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اطاريح الدكتوراه لفرع علم المواد

Evaluation of the Effect of Sisal Fibers on Some Physical Properties of Heat Cured Acrylic Denture Base

By:Teba Mageed Hameed   Supervised By:Prof .Dr. Balqees AL-Dabbagh & Prof Dr. Raghdaa K. Jassim    year:2022

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Poly methyl methacrylate (PMMA) is commonly used for the construction of removable partial or complete dentures. This materials is frequently used because it has various advantages. In spite of its advantages, PMMA has several limitations, one of these disadvantages is its poor mechanical properties that causes denture base to break easily. The aim of this study was to evaluate the effect of natural sisal fibers, micro sisal powder and Nano sisal powder on the mechanical properties) and physical properties of denture base materials. The present study was design to make (560) specimens and divided into seven groups depended on the form and concentrations of reinforcing materials, the first group for control group (without additives) and other groups for sisal fibers, micro powder and Nano powder, each groups further subdivided into seven subgroups for the experimental test (impact strength, flexural strength, tensile strength, surface hardness, surface roughness, thermal conductivity and water sorption and solubility test) . Statistical analysis of data was performed using descriptive and interfacial statistics. Data was considered statistically significant at level of < 0.05. FTIR results showed a chemical changes have occurred after treatment. A new absorption band was developed after sialne treatment. Results showed a highly significant increase in impact strength of composite of PMMA/ sisal fibers as compared with control groups, yet there was no significant effect in impact strength of micro and Nano powder reinforced PMMA. Interestingly significant increase was observed in flexural strength for groups of micro and Nano powder reinforced PMMA groups, yet non-significant in flexural strength of specimens reinforced with sisal fibers. Clear increase was noticed in tensile strength mean values of all specimens reinforced with sisal fibers, micro powder and Nano powder as compared with control group. Reinforcement of PMMA with micro sisal powder result in increase in surface roughness and decrease in surface hardness. The incorporation of Nano sisal powder into resin result in decrease in surface hardness and surface roughness. The addition of sisal fibers into PMMA resulted in non-significant differences in surface properties. Thermal conductivity decreased at (5% and 10%) wt of sisal fibers. Non- significant effect in thermal conductivity of specimens reinforced with micro and Nano powder. A statistically highly increase in water sorption and solubility of all specimens reinforced with sisal fibers, micro powder and Nano powder.

Foamed Concrete Properties Enhancement by Some Additives

By:Ruqaya Falah Hamada Alhammadi   Supervised By: Prof. Dr. Awham Mohammed Hameed   year:2021

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Building materials and technologies in the world have evolved in line with the new requirements for construction, which have spread throughout the world to reduce damage to the environment and reduce energy consumption, and rely on renewable energy sources. This work was prepared at identifying the possibility of using Foamed concrete. The mechanical and physical properties of this concrete were investigated compared with normal concrete. Two types of foams were used to prepare the foam concrete to obtain high quality with target density was nearly 1600kg/m3. The standard samples were designed by employing two types of foaming agent (FA), the first one is commercially named (EABSSOC foam agent, FA) while the second is the foam of detergent liquid (D). The added foam percentage was (1 and 0.8) wt. % to fabricate the foam concrete. Glass fibers, silica fume were used as synthetic fillers with proportion 1, 3, 5 wt. % of cement. The using recycled materials such as glass powder; rubber waste was utilized as recycled fillers with different ratios. The amounts of rubber waste and glass powder used as additive in foam concrete were 1, 3, 5 wt. % of rubber waste and 1, 0.7 wt. % of glass powder. The 624 samples were prepared according to the standard specifications of each tests. The fresh tests included (flow test and setting time). Some mechanical and physical properties tests were performed including (compressive strength, flexural strength, splitting tensile strength, thermal conductivity, porosity, water absorption, Ultrasonic Pulse Velocity (UPV) and Acoustic Impedance (AI) and Scanning Electron microscope (SEM). All samples were cured in (water, air) for various durations included (7,14 and 28) days. The results showed that the perfect composition which involved 1wt. % of (D) gave higher values of the compressive and flexural strength (F.S), splitting tensile strength compared to the samples that involved 1,0.8wt. % of foam agent (FA). It is obvious that the addition of foam to the cement mortar paste imparts great characteristics as lightweight with flowability. The mechanical properties were decreased with increasing the percentage of foam agent (FA) and detergent (D) of the mixture design. Foam concrete reinforced with 1wt. %glass fiber Abstract II (GF), silica fume (SF), rubber waste (RW) and 0.7wt. % glass powder (GP) with 0.8wt% detergent (D) have the better compressive strength, flexural strength (F.S) and splitting tensile strength then that samples which contained the same percentage of reinforcement with 0.8wt. % foam agent(FA). The results showed that FA sample records the lower bulk density compared to the (D) sample. It is found that the best value of thermal insulation is equal (0.42668 W/m. ºC) for the sample contained 1wt.% FA and (0.4096 W/m. ºC) of 1wt.%FA+1wt.% glass powder(GP), while the sample of 0.8wt.%FA with enhancement 3wt.%glass fibers (GF) gave (0.5583 W/m. ºC) but the other additive 5wt.% silica fume (SF) recorded (0.60047W/m.ºC). The porosity was improved with decreased (FA) content and the increasing of addition of glass powder, glass fiber, rubber waste lead to decrease the porosity value, but it increases with increasing the content of glass fibers of 0.8wt.% (D) sample. The best ultrasonic pulse velocity and acoustic impedance values were obtained for the samples cured at 28days into air and water. It can be concluded for that the values of (UPV) (AI) increased with increasing FA to 1wt. % and also when the content of FA and D decreased to 0.8wt. % with reinforcement 1wt. % of GP, SF, RW and 1,5wt. % of GF. The foam concrete samples that contain 1,0.8 wt.% FA and after adding 1wt.%GP, GF, RW and 5wt.% SF have lowest values of water absorption than that contain of detergent sample. Hybrid reinforcement was prepared by mixing 1wt.% of GF and SF together and then it was added to each sample of 0.8wt.%FA and D respectively. It is noticed that the properties of hybrid (FA)concrete are lower than the properties of hybrid (D) concrete, but the first recorded better thermal insulation and the lowest water absorption values. Finally, the finding of this study is encouraging to use the reinforced foamed concrete with some additives and recycled waste for some applications such as thermal and acoustic insulation purposes, non-structural section, floor leveling and filling of voids.

Synthesis and Characterization of Nano Alumina toughened Zirconia - Glass Composites

By:Sara Nabil Ibrahim   Supervised By:Prof. Dr. Shihab A. Zaidan & Assist. Prof. Dr. Mudhafar A. Mohammed    year:2021

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Yttria stabilized tetragonal zirconia polycrystalline/Alumina (3Y-TZP/Al2O3) - glass composite were prepared by adopting a new method (melt-infiltration process) to preparing ceramic composite bodies for technical and medical applications, most notably the dental industry such as crowns and bridges. First of all, two groups of cylindrical porous (Zirconia-Alumina) composite specimens were prepared using two weight percentages of nano alumina Additives (10 and 20 wt.%) through powder compaction method. A graphite powder (0,10,20,30 and 40 wt.%) was added as an additive to produce porous Alumina toughened zirconia (ATZ). The composite specimens were sintered in air at 1500 °C for 1:30 hrs. followed by glass infiltration method. Glass powder mixture was prepared by mixing 18%wt lithium hydroxide with 72 wt. % feldspar, and 10 wt.% Nano titanium dioxide. The glass slurry prepared from glass powder and water has been uniformly pasted by a brush on the surface of sintered porous alumina toughened zirconia specimen, then dried in oven at 50 ºC. Specimens then heated in an electric furnace in air at 1185 ºC for 2hrs. the melted glass infiltrated into the porous matrix by capillarity action. The glass application on specimens was repeated 5 times so that glass penetrated through higher amount of porosities. The total 10 ATZ specimens where tested before and after glass infiltration. The effect of porosity on Physical, mechanical, structural and surface properties have been investigated before glass infiltration. The results showed that porosity and water absorption increased while bulk density decreased with the increase of graphite additives. The Linear firing shrinkage of ATZ specimens was increased with decreasing porosity ranging from 11.2 to 19.16 % for 3Y-TZP/10 wt.% Al2O3 and from 8.12 to 16.2% for 3Y-TZP/20wt.% Al2O3 specimens. The elastic modulus and diametrical strength values decreased with increasing porosity, these values ranged from 141 to 24 GPa and from 50.3 to 7.1 MPa respectively for 3Y-TZP/Al2O3 while for 3Y-TZP/20 wt.% specimens these values ranged from 159.6 to 27.2 GPa and 74.7 to 8.7 MPa respectively. XRD test performed for structural analysis of ATZ Page | XIV specimens. It showed that as porosity increased the crystallite size.. AFM test was used to determine ,Grain size and roughness of ATZ specimens. The results showed increment in grain size and roughness with increasing porosity content, and decreament with increasing alumina additive. Another physical, mechanical and microstructural tested were performed after glass infiltrated into porous ATZ specimen .Linear firing shrinkage values have been calculated, it was found that shrinkage values ranged between (0.12-0.53)%. Young modulus and diametrical strength values also calculated. These values were (183-95GPa) and (57-24.3MPa) respectively for 3Y-TZP/10wt.% Al2O3 while it shows higher values for 3Y-TZP/20 wt.%Al2O3 (195-109 GPa) and (80.1-26.7 MPa) respectively. Microhardness indentation test was used to determine hardness and fracture toughness of ATZ-Glass specimens, the results showed that hardness value decreased with increasing in alumina additives. The fracture toughness also calculated from the parameters obtained by microhardness test, fracture toughness values wereranged from (0.53 to 1.03 MPa .m1/2) for 3Y-TZP/10 wt.% Al2O3 and it increased forTZP/10 wt.% Al2O3 s from (0.53-1.54) MPa . The enhancing of ATZ properties by infiltrating A lithium silicate glass into the structure of porous ATZ was demonstrated in this work. Glass infiltration led to the removal of surface defects andflaws, thereby improves the reliability of the specimen. the increment percentage of strength depends on porosity content in ATZ before infiltration. The advantage of adding glass through glass infiltration process summarized by obtaining materials distribution in low temperature below 1200 °C, with preserving the final structure without deformation.

Preparation of Glass-Ceramic Systems and Studying Their Properties

By:Duraid Fawzi Mahdi   Supervised By: Prof. Dr.Shihab A. Zaidan & Ass. Prof. Dr.Muthafar F. Al-Hilli    year:2021

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The lithium metasilicate glass-ceramic Li2SiO3 was prepared from glass binary system Li2O-SiO2 with composition percentages 45 wt% Li2O and 55 wt% SiO2 which is a eutectic non-stoichiometric mixture. The preparation technology method of lithium metasilicate glass-ceramic was the powder method. The nano-frit was produced with melting – quenching method by melt the glass batch in the platinum crucible (90Pt – 10Rh) at 1195 OC for 2 hr. The glass melton was quenched in cold water at temperature 3OC and then the produced frit was milled by agate mortar. Once again, these steps were repeated for more homogeneity of the produced nano-frit. Four groups of glass-ceramic were prepared, in each group included five specimens. The weight for every specimen was 0.5 g with dimensions 10 diameter × 2.5 thickness mm formed by biaxial pressing at 5 ton pressure for 30 sec. The change in temperatures of the heat treatment as indicating 750, 800, 850, 900, and 950OC at constant time equal to 4 hr was studied in the GLS-C group. Also the change in time of the heat treatment as indicating 2, 4, 6, 8, and 10 hrs at constant temperature equal to 800OC was studied in the GLS-H group. These two groups were formed without any addition of the nucleating agents. Two types of nucleating agents were added to the nano-frit and studied their effects at constant temperature 800OC and time 4 hrs of the heat treatment. The changes in addition percentage of P2O5 as indicating 4, 7, 11, 14, and 18 wt% as the first type of nucleating agent were studied in the group GLSp. The second type of nucleating agent was a mixture of P2O5 and TiO2 with addition percentages in wt% as follows: 3 P2O5+ 1 TiO2, 5.25 P2O5+ 1.75 TiO2, 8.25 P2O5+ 2.75 TiO2, 10.5 P2O5+ 3.5 TiO2, and 13.5 P2O5+ 4.5 TiO2 were investigated in the group GLSpt. The investigations about the change effect on the four parameters mentioned above had been done such as XRD, AFM, FESEM, bulk density, volume shrinkage, and loss of ignition. Two software were used, one for structural analysis as abbreviated name EXPGUI within software system GASA used for refinement and calculate the percentages of crystalline phases and glass phase. The other was Image J 5.2i software used for calculation of mass fraction and density for the crystalline phases within the glass-ceramic. All the investigations appeared the crystalline phase's formation within the nano-frit. The best results were the highest value of the crystalline phase density (CPD) and a mass fraction (MF) equal to 910 No/mm2 and 11% respectively at a heat treatment temperature of 950OC. The highest value of the bulk density and volume shrinkage was 1.95 g/cm3 and 19.7% respectively also at a heat treatment temperature of 950OC. The lowest value of loss of ignition (LOI) was 13% at nucleating agent percentage 3% P2O5+1% TiO2 equal to 4%. The best parameters were obtained a desired quantity of the crystalline phases, bulk density, high volume shrinkage, and low LOI were temperature 950OC, time 6 hrs of the heat treatment, and nucleating agent percentage 3 wt% P2O5+1 wt% TiO2. Four glass-ceramic specimens were prepared according to the above best parameters and the same composition 45 wt% Li2O and 55 wt% SiO2. One with 0% CuO addition LSGC and the rest with 1 wt% LC1S, 2 wt% LC2S, and 3 wt% LC3S of CuO addition. The specimens formed compact discs with dimensions 18 diameter × 2.58 thickness mm by the same previous method. The breakdown voltage test was done executed at 10 different spots in each specimen and Weibull modulus was used to know the homogeneity of dielectric strength property. It got a good match between Weibull modulus results and FESEM images which indicating that Weibull modulus is the active tool that can be used for knowing the homogeneity of any property. The high average dielectric strength is 9.116 kV/mm for LC1S while the lowest average dielectric strength is 7.101 kV/mm for LSGC. The high value of Weibull modulus is 9.0792 for LC2S which means good homogeneity for the dielectric strength while the lowest Weibull modulus value is 4.0932 (lower homogeneity) for LSGC.

Preparation and Characterization of Bioco mpatible PVA/Starch , PVA/PEG and PVA/Starch/ PEG Polymeric Blends

By:Bushra Hosni Musa   Supervised By:Prof. Dr. Nahida J o umaa Hameed    year: 2021

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The present work aimed to study the chemical crosslinking effect by using glutaraldehyde (GA) at various weight ratios (5, 8, and 10) % on the biological, mechanical, thermal, structural, and physical properties of polyvinyl alcohol/starch (PVA/St) blends, poly(vinyl alcohol)/ poly(ethylene glycol) (PVA/PEG) blends, and (PVA/St/PEG) blend films. PVA/St, and PVA/PEG blends at different ratios (25, 30, 35, 40, and 50) wt % of St and PEG as well as PVA/St/PEG ternary blend at (12.5/12.5) wt% of St/PEG were prepared by conventional solvent casting technique. The results of mechanical properties verified a decrease in the ultimate tensile strength with St and PEG ratios increase. The highest tensile strength was (28.2 MPa) for (PVA/ 25 wt% St), (20.95 MPa) for (PVA/25 wt% PEG), and (32.87 MPa) for (PVA/St/PEG), also with increasing GA from (5) to (10) %, the value of tensile strength of crosslinked (PVA/25% St) blends, (PVA/25% PEG) blends, and ternary blends increased from (33-41.19 MPa), (26.66-35.15 MPa), and (38-42.5MPa) respectively compared to PVA and its blend before crosslinking, while the elongation at break % decreased for all blends before and after crosslinking. FTIR results proved that the possibility of PVA and starch, as well as PVA and PEG, can interact physically with one another and formation of H-bond in the films which may increase the compatibility of the components. Also, it showed a chemical cross-linking reaction that happens between (PVA/St) blend and glutaraldehyde. DSC results demonstrated that PVA had glass transition temperature Tg (83oC), and a sharp maximum endothermic peak at (224oC) due to a melting transition (Tm), while starch had Tg (85 oC) and Tm (130 oC), also PEG had Tg (52 oC) and Tm (172 oC). One Tg value was found for PVA, St, PEG, (25, and 30) wt% of St blends, and (25, and 30) wt% of PEG blends owing to a good blend miscibility whereas, two Tg values were found for (35,40,50) wt% St, (35, 40, 50) wt% PEG and ternary blend owing to blend immiscibility. Also, it elucidated an increase in Tg, and reduction in Tm of (PVA/St) blends but a decrease in Tg, and a reduction in Tm of (PVA/PEG) blends as compared to the pure PVA. Abstract In thermogravimetric analysis "TGA", the weight loss happened in three stages of all blends, while in starch and 50 wt% PEG, it occurred in two stages and one stage in PEG. The water absorption outcomes proved that there was an increase in swelling ratios with increasing starch and PEG ratio as a function of time. The lowest swelling ratio was for PVA, whereas the PVA/St (50/50 wt/wt %) and PVA/PEG (50/50 wt/wt %) had the highest values. The swelling behavior of the crosslinked polymer blends samples was investigated in several media, including neutral, acidic, and alkaline (pH7.3, pH2 and pH5.5, and PH8), as well as distilled water. The swelling ratio of the crosslinked polymer blends increased with the pH buffers increase as (pH8 > pH7.3 > distilled water> pH5.5> pH2), and the water absorption of all blends decreased with increasing GA concentration because of an increase in crosslinking in the polymers blends. The rate of the release of drug in pH7 was more than that of pH2. FESEM results indicated that the (PVA/25 wt% St) blend and (PVA/25 wt% PEG) blend had a nearly homogeneous and smooth surface with some voids and with no signs of phase separation. The (PVA/25 wt% St) blend+10 %GA and (PVA/ 25 wt% PEG) blend+10% GA samples offered less homogeneity with one another, and an apparent phase separation took place. The PVA/St/PEG ternary blend image manifested that non-uniform surface and there some aggregates of St and PEG in the PVA matrix. While, many irregular aggregates were detected on the surface of the (PVA/St/PEG) blend +10% GA sample. It can be observed from the phase structures of (PVA/25wt % PEG) blend with 10% GA and 150 mg of Erythromycin drug that there is a much lesser agglomeration of PEG particles and also a very little formation of voids due to the drug. Cytoxicity test results evinced that there are good viability percentages; therefore there is no toxic effect of blends on the WRL 68 cells. The current study proved that the prepared crosslinked samples (PVA/25%St, and PVA/25% PEG blends) could be used for drug delivery applications.

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اطاريح الدكتوراه لفرع الفيزياء التطبيقية

Fabrication of Perovskite Ferroelectric (Ba, Sr) TiO3 Nanorods films for Photovoltaic Applications

By:Thamir Hassen Ali   Supervised By: Prof. Dr. Mukhlis M. Ismail Asst.Prof. & Dr. Odai N. Salman    year:2022

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In this study, barium strontium titanate Ba1−xSrxTiO3 (BST) where, (x = 0.2, 0.25 and 0.3) nanostructures were effectively produced on TiO2 nanorod films formed on fluorine tin oxide (FTO) substrates using the hydrothermal process, which is a high-velocity, simple, and economical technology. To identify the optimal condition, the growth characteristics (reaction time and varied concentrations) were studied in this research. The electrical, structural, and optical characteristics of TiO2 and BST films have been widely explored and characterized under a variety of circumstances. X-ray diffraction and field emission scanning electron microscopy measurements were used to analyze the structure and surface morphology of TiO2 and BST nanorod. At 4 hours, BST nanorod films with varied concentrations (0.2, 0.25, and 0.3) were prepared. The production of rutile TiO2 and BST nanorods was verified by X-ray analysis, and the nanorods were orientated in the [002] and [100] directions, with the grown axis perpendicular to the FTO and TiO2 substrate. The crystallinity of TiO2 film was raised by increasing the growing period from 4 to 30 hours, while the crystallinity of BST film was increased by increasing the concentration from 0.2 to 0.3. The film with a concentration of 0.3 exhibited well crystallization. FESEM tests revealed that the nanorods were tetragonal in form, and that the morphology (density, length, and diameter) of the nanorods may be modified by modifying the development period and using varied concentrations of TiO2 and BST. The optical characteristics of TiO2 and BST films, such as transmittance, absorption coefficient, and energy gap, were investigated for a variety of growth times and concentrations. With varying reaction time, the optical energy band gap of TiO2 reduced from (3.14 to 3.0) eV. The optical energy band gap of BST changed from (3.22 to 3.06) eV with various concentration. TiO2 and BST conductivity has been studied. For the various parameters, hall measurements revealed that the TiO2 nanorod is n-type semiconductor. At proper circumstances (10 hours and 0.3) highly ordered vertically aligned TiO2 and BST nanorods may be formed. Solid-state dye-sensitized solar cells (ss-DSSC) and recently developed perovskite solar cells (PSCs) have attracted a great attention in the scientific field of photovoltaics due to their low cost, absence of solvent, simple fabrication and promising power conversion efficiency (PCE) . In these types of solar cell, the dye molecule or the perovskite can harvest the light on the basis of electron excitation. Afterwards, the electron and hole are collected at the charge transport Materials. The effect of Spiro-OMeTAD on the solar cell performance was observed and characterized. The increased conductivity of the Spiro-OMeTAD layer and enhanced charge transfer at the Au/Spiro-OMeTAD interface facilitated the solar cell performance.The solid-state dye-sensitized solar cell (ss-DSSC) demonstrated an overall photoelectric conversion efficiency of 3.14%.

Synthesis of ZnO-Au nanoparticles and study their biomedical applications

By: Taha Mohsin Rashid   Supervised By: Prof. Dr. Uday M. Nayef & Prof. Dr. Majid S. Jabir   year:2021

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There are many methods for preparing nanoparticles but the safety, easy, and low-cost methods, become more important and useful. Therefore, Pulse laser ablation in liquid (PLAL) it’s one of an important method distinguished by low cost, safety, and easy. Au NPs and ZnO NPs, and Au/ZnO NPs have been prepared by PLAL as a colloidal solution by different energies with different structures once [email protected] as a core/shell nanoparticle (CSNPs) and other Au/ZnO as a nanocomposite (NCs). The characterization for nanoparticles confirms the internationality of materials, XRD results show the phase of Au NPs is cubic and crystallite size is (40.5, 32.78, and 30.94) nm according to energies (400, 600, 800) mJ, respectively. While the phase of ZnO NPs is hexagonal and crystallite size is (38.5, 20.92, and 27) nm according to energies (400, 600, 800) mJ, respectively. Transmitted electronic microscopic (TEM) is used to check the morphology of particles, and UV-Visible Spectroscopy is used to show the absorption peaks, while, Fourier-transform infrared spectroscopy (FTIR) is used to study the types of binding bonds. In this study, antioxidant activity, antibacterial, and anticancer activity have been studied, the result of Au/ZnO CNs is more effective as an antioxidant than Au NPs and ZnO NPs as an individually. The biomedical applications in one of more important filed, therefore, the activity of Au NPs, ZnO NPs, and Au/ZnO NCs as antibacterial appears large inhibition zones for Au/ZnO NCs against S. aureus than E. coli, and also it’s more effective than Au NPs, ZnO NPs as an individually. The cytotoxicity of nanoparticles against two types of cell lines has been studied, first against breast cancer (AMJ13) and second, against oesophagal cancer (SK-GT-4), the percent of kills of AMJ13 is more than SK-GT-4. the cytotoxicity of Au NPs is 78.33 ± 2.404, and the ZnO NPs are 69.67 ± 1.453. While the cytotoxicity of Au/ZnO NCs is more effective than individually of Au NPs and ZnO NPs, and more efficient for penetrated the membrane of the cell line, therefore, increased percent of kills, it was 88.67 ± 1.764. While, the cytotoxicity effect of Au NPs, ZnO NPs, and Au/ZnO NCs against SK-GT-4 cell, Au NPs is 80.00 ± 2.082, and the ZnO NPs is 70.67 ± 1.764. And for Au/ZnO NCs is more effective than individually Au NPs and ZnO NPs, it was 87.67± 1.

Synthesis and Characterization of ZnO nanoparticles for antimicrobial applications

By:Shaymaa Noaman Ismail AL-Jaafari   Supervised By: Dr. Ahmed N. Abd & Dr. Osama Abdul Azeez Dakhil   year:2020

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Zinc Oxide Nanoparticles has been prepared at difference methods for antimicrobial applications, also, this study deal with the relationship between the concentration of ZnO NPs (0.01, 0.02, 0.04, and 0.06) mg\ml and their activity in different Bactria and fungi. The first part has been prepared ZnO NPs by (electrolysis method, chemical methods, and aqueous hydrolysis methods), moreover, the standard zinc oxide nanoparticles are used for comparison. The second part is colloidal deposit on a glass by drop casting method with thickness (1 µm100 nm), the ZnO thin film study the characteristics of prepared samples (electrolysis method, chemical methods, and aqueous hydrolysis methods) and a standard zinc oxide nanoparticles. XRD data were useful to calculate the mean crystal size by Scherer equation. The AFM images indicated that the shapes for all samples are spherical shapes furthermore, SEM images with EDX to confirm ZnO form. The optical properties for the freshly ZnO collided were study by The UV-Visible spectroscopy, the results shows the ZnO nanoparticles have a high transparent at the visible range, also the optical energy gap is around (4.3, 5.7) eV due to quantum size effects. The third part has been focused on studying the antimicrobial activity of Zinc Oxid nanoparticles was studied against human pathogenic Microorganisms including Escherichia coli, Staphylococcus aureus, Bacillus subtilis, and Pseudomonas aeruginosa; in addition to Candida albicans. The best preparation of zinc oxide nanoparticles according to characterization and medical application (antibacterial and aticandida) was electric methods; the results showed that the best concentration in the inhibition zone is (40) mm in Bactria (E.coli and S. aureus) at the concentration of (0.04) mg/ml, whereas in Candida was (45) mm at concentration of ZnO NPs (0.04) mg/ml.

Synthesis and Characterization of Fe3O4 and Fe3O4 Capped PEG Magnetic Nanoparticles and Study Its Medical Applications

By:Waleed Kamil Abdulkadhim   Supervised By:Prof.Dr. Uday M. Nayef & Prof.Dr.Majid S. Jabir    year:2019

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The magnetite nanoparticles (Fe3O4) capped with polyethylene glycol (PEG) were prepared by hydrothermal method, the successful coating of PEG molecules on the surface of (PEG–Fe3O4).These nanoparticles exhibited excellent dispersibility and dissolvability in physiological condition. The obtained nanoparticles were characterized via X-ray diffraction (XRD), Transmission electron microscopy (TEM), Fourier transform infrared (FTIR) spectroscopy, vibrating sample magnetometer (VSM) and thermogravimetry (TG). The average diameter of bare Fe3O4 and PEG- Fe3O4 (Low, medium and high concentrations) magnetic nanoparticles diameter was (9,5,3 and 8)nm respectively and exhibited superparamagnetism and high saturation magnetization at room temperature. Biological effect was studied on two bacterial strains: Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Most of modified magnetite nanoparticles had a significant effect and more on S. aureus and less on E. coli, where as PEG- Fe3O4 magnetic nanoparticles displayed significant effect on the growth rate of bacteria. The present study aimed at investigation of (bare Fe3O4 and PEG–Fe3O4) toxicity using both morphological and functional criteria. The biochemical parameters were assessed by laboratory mice for 7, 14, 21 and 28 days after administration of MNPs. Furthermore, the histological structure of liver, spleen, kidney samples were analyzed. Intravenous infusion of (bare Fe3O4 and PEG–Fe3O4) (1 mg/kg) was not associated with significant changes in biochemical parameters. The histological remained unchanged through the entire observation period. The body weight was non-significant changed through long period after administration of MNPs. The magnetic nanoparticles (bare Fe3O4 and PEG–Fe3O4) under effected induction heating or photothermal are investigated for cancer therapy of in vitro experiments, was measured by MTT assay. The ability of (bare Fe3O4 and PEG–Fe3O4) in induction of apotosis have been done using Acridine orange/ Ethedium bromide stains. Cytotoxicity effect of (bare Fe3O4 and PEG–Fe3O4) against SKOV-3 cells in the presence and absence of laser photothermal therapy and alternating magnetic field (AMF) has been done. Treated of SKOV-3 cells with (bare Fe3O4 and PEG–Fe3O4) significantly increased ROS formation. The heat is found to be rapidly generated by induction heating or near-infrared (NIR) range laser irradiation of magnetic nanoparticles with spherical shape. Both (bare Fe3O4 and PEG–Fe3O4) can be examined by SKOV-3 cancer cells and obviously little affect on cell structure and viability. Where, in another examinations induction heating and laser irradiation at 808 nm was used, however, the SKOV-3 cancer cells viability were effectively suppressed, and the cellular organelles were obviously damaged when incubated with the magnetic nanoparticles after exposure to NIR laser irradiation or (AMF)induction heating. The morphological examination revealed that after a induction heating or photothermal therapy, the SKOV-3 cancer cells structure exhibited discontinue, the cells were significantly wilted and some cells have finals scrappily. Where, PEG-Fe3O4 showed higher cytotoxicity in SKOV-3 cancer cells as compared to bare Fe3O4 , which obviously the more of inhibitions when magnetic nanoparticles treated SKOV-3 cancer cells were exposed to(AMF) induction heating and less of this at exposure to NIR laser irradiation .

Effect of doped Au, Ag with rGO/PS for sensing applications.

By:Haitham Talib Hussein   Supervised By:Prof. Dr. Uday Muhsin Nayef & Assistant.Prof. Dr. Adi M. Abdul Hussien    year:2019

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In this work, p-type silicon wafer (111) orientation was used for preparing porous silicon (PS) layers by electrochemical etching (ECE) method, with resistivity of silicon wafer of about 1.5-4Ω.cm.The etching solution consists of hydrofluoric acid and high purity ethanol (C2H5OH) by electrolyte solution concentration HFc=15%. PS samples were prepared at different current densities 2, 4 and 6mA/cm2, and fix time of etching 15min. structural, morphological, chemical, optical and electrical properties are studied by X-ray diffraction (XRD), atomic force microscopy (AFM), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, photoluminescence (PL) and J-V measurements respectively. The PL experiences are conducted in air and different organic vapor like ethanol, n-hexane, chloroform and H2O vapor. These results showed that the higher PL intensity was at etching current density 4mA/cm2. Synthesis of reduced Graphene oxide (rGO) layers was done by electrochemical exfoliation technique, The SEM, FE-SEM, XRD, Raman spectroscopy and UV-Visible spectroscopy are used for investigation of rGO properties. The SEM images showed the thin sheets of rGO layers. While the Raman test illustrated the D, G and 2D that spectrum peaks at 1350cm-1, 1587cm-1 and 2703cm-1 respectively. The experience of UV-Visible clarified the high transparent of rGO layers. The rGO suspension at concentration was 0. 5 mg/ml was deposited on PS were prepared at different current density 2, 4 and 6mA/cm2 (3 drops). The rGO/PS characteristics were investigated by SEM, AFM, and XRD. While the FTIR examine was investigate the presence of Si-C, C=C, C-O, C-H bonds. The current-voltage measurements features were done in dark and with white light illumination at different power intensities, these results indicated that the rGO layers lead to increase of electrical current. Also the rGO/PS samples showed that the PL intensity increase compare with only PS layer. The higher PL was at etching current 4mA/cm2 which depends on amount of rGO layers inside and on the surface of PS. and affected by organic vapors n-hexane, chloroform, ethanol and H2O vapor. The PL intensity decreased when exposed to this vapors. The amount of decrease was significant when compared with PS layer alone. As the result of PS surface was improved as a vapors sensor. The gold (Au) and silver (Ag) nanoparticles were prepared by laser ablation method. The gold and silver targets were immersed in double distilled deionized water (DDW) using Nd:YAG laser with laser energy 400mJ, number of pulses was 500 and laser wavelength 1064nm. These nanometals were used as doping materials for rGO by ratio 1:9. The FESEM and UV-Visible tests were used for studying the properties of AuNPs, AgNPs and for rGO:nanometals. The suspension of rGO:AuNPs and rGO:AgNPs was deposited on surface of PS (3drops). The characteristics of rGO: MetalNPs/PS was obtained by SEM, AFM, XRD and the FTIR techniques. The PL measurements were done for all rGO:metal nanoparticles samples, they were conducted in air and different organic vapors, these results shown obviously that the PL intensity in air was higher than only PS layer and rGO/PS samples, the quenching of PL when exposed to organic solvents vapors was greater than other samples (PS layer and rGO/PS), the PL quenching value of chloroform was lower than ethanol and greater than n-Hexane.

Spectroscopic Analysis of (Cu, Al and Ag) Plasma Produced by Nd: YAG Laser

By:Noor Malik Saadoon Al-Musawi    Supervised By: Dr.Sabah Habeeb Sabeeh & Dr.Naseer Mahdi Hadi    year:2019

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In this work, metallic nanoparticle was prepared by an efficient and size –controlled. Structure and surface morphology of Nanoparticles were characterized by X-ray diffraction (XRD), Atomic Force Microscope and Scanning Electron Microscopy measurements were investigated. Annealing proses was in air at a specifics temperature of 300º C and at a constant time of 75 min the XRD for Cu - NPs technique that showed these films are monoclinic structure with a preferred orientation. Lattice parameters are (a = 4.84, b = 3.47 and c = 5.33) Å. Corresponding to plane (002) and (111), (222) ,(113) the XRD profile of Al-NPs was shown with diffraction peaks of (111), (200), (220) and (311), where the peaks at 111 and 200 were the most intense. The estimated average size corresponding to the most intense crystallographic plane (111) was determined to be 40 nm. The AFM Analysis suggested the size of Al-Ps as 45 nm. Four sharp peaks appeared at 2θ = 38.5º, 44.7º, 64.7º and 77.6º which can be assigned to the (111), (200), (220), and (311) planes of the face centered cubic (FCC) structure of metallic silver. In the second part for diagnosis the metal sample for Al, Ag Cu emission spectroscopy with different laser energy of 81.5,134.5,221 , 240 and 319 mj with a specific distance between the fiber optic and the target with 5mm, where the experiment was in air. Identification for emission spectrum line was analyzed based on the NIST data base. It is noticed that the intensity of spectrum lines, which is in (a.u) , increases with laser energy increase; in addition, the plasma parameter for electron temperature and electron density number also increase that for bulk material .For the enhancement of the LIBS technique we diagnosis the nanoparticles emission spectroscopy and calculated the plasma parameters. It was found the intensity increases in different values higher than for bulk material with the same position for peaks, plasma parameter also increases for electron temperature also reached to saturation value but the values electron density number decrease for NE-LIBS.

Modification and Characterization Carbon Nanomaterials and Hybrid Materials for Antibacterial and Anticancer Activities

By:Mustafa K. A. Mohammed   Supervised By:Dr. M. R. Mohammad & Dr. Duha S. Ahmed    year: 2019

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In this study, raw single wall carbon nanotubes (R-SWCNTs) and raw multi wall carbon nanotubes (R-MWCNTs) were chemically functionalized with sulfuric acid (H2SO4) and nitric acid (HNO3) to produce functionalized-SWNTs (F-SWNTs) and functionalized-MWNTs (F-MWNTs). The improving of dispersion ability was investigated with ultraviolet-visible (UV-Vis) spectrophotometer and Zeta potential analysis. The results showed higher absorption band for F-SWNTs and F-MWNTs compared with R-SWNTs and R-MWNTs. In addition, the Zeta potential values were increased from -7 to -42 mV for SWNTs, while for MWNTs from -9 to -51 mV. This indicates that the dispersion ability of SWNTs and MWNTs has been enhanced after acid treatment. The formation of oxygen functional groups (-OH, -COOH) onto the surface of SWNTs and MWNTs after acid treatment was verified by the Fourier transform infrared (FTIR). The X-ray diffraction (XRD) and Raman spectroscopy results showed that the structure of SWNTs and MWNTs was intact after being treated with strong acids. The (002) diffraction peaks for SWNTs and MWNTs were appearing before and after functionalization process. Moreover, the crystalline structure of SWNTs and MWNTs have been observed in the Raman spectra with the D-band, G-band, 2D-band, which are characteristic bands for carbon nanotubes (CNTs) structure. The field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), and energy dispersive spectroscope (EDS) exhibited that the short tubes with less aggregation of SWNTs and MWNTs were observed after being treated in H2SO4/HNO3 mixture. After functionalization and characterization of SWNTs and MWNTs, the preparation of hybrid materials was carried out. The ZnO/Ag-SWNTs, ZnO/Ag-MWNTs, ZnO/Au-SWNTs and ZnO/Au-MWNTs hybrids were prepared by using co-precipitation method. Zinc acetate dehydrate (ZnC4H10O6) and silver nitrate (AgNO3) were used to prepare ZnO/Ag nanoparticles (NPs). While, gold chloride trihydrate (HAuCl4.3H2O) and zinc acetate dehydrate were used to prepare ZnO/Au NPs. The TiO2/Ag-SWNTs and TiO2/Ag-MWNTs hybrids were synthesized by using the sol-gel technique. Titanium isoproproxide (TTIP) and AgNO3 were used as precursors to prepare TiO2/Ag NPs. Higher Zeta potential values were observed for all hybrids in comparison with R-SWNTs and R-MWNTs, but lower than F-SWNTs and F-MWNTs. The UV-Vis measurements suggest that the optical band gap for all hybrids was decreased after loading NPs. The FTIR and Raman spectroscopy results for hybrid materials confirmed the formation of ZnO/Ag, ZnO/Au, and TiO2/Ag NPs with SWNTs and MWNTs. The crystalline structure of hybrid materials was characterized with XRD. The hexagonal wurtzite structure of ZnO was appeared for ZnO/Ag-SWNTs, ZnO/Ag-MWNTs, ZnO/Au-SWNTs and ZnO/Au-MWNTs hybrids. Whereas, the anatase phase of TiO2 was appeared for TiO2/Ag-SWNTs and TiO2/Ag-MWNTs hybrids. The (002) diffraction peaks of CNTs were showed in all hybrid materials. The electron microscopy (FESEM & TEM) images and qualitative analysis of EDS verified loading of ZnO/Ag, ZnO/Au, and TiO2/Ag NPs onto the SWNTs and MWNTs walls. The antibacterial activity of raw-(SWNTs & MWNTs), functionalized-(SWNTs & MWNTs), and hybrid materials were evaluated by using the colony forming assay, and fluorescence microscope. Escherichia coli (E. coli) as Gram-negative and Staphylococcus aureus (S. aureus) as Gram-positive were employed as the target bacteria. The hybrid materials were reported to possess highest antibacterial ability towards E. coli and S. aureus bacteria after incubation for 24 h. Besides, the antibacterial efficiency of hybrid materials was increased after incubation under UV radiation for 2h. The photocatalytic properties of NPs were played an important role for inhibiting bacterial growth. The fluorescence and FESEM images demonstrated that the hybrid materials had the strongest effects on the membrane integrity of E. coli and S. aureus bacteria. The anticancer activity of hybrid materials against human cervical cancer (SiHa) cells and human hepatic (WRL68) cells was assessed by using MTT assay. The cell viability was found to decrease in concentration dependent manner after incubation for 24 h. The SWNTs exhibited higher toxic effect on cancer cells than MWNTs because of difference in physicochemical properties. The hybrid materials have potential to selectively kill cancer cells with less affecting normal cells.

Photothermal Therapy of Cancer Cells Using Direct Coated Gold NPs

By:Lamyaa Fadhil AL-Barram   Supervised By:Dr. Selma M.H. AL-Jawad & Dr. Ali A. Taha    year: 2019

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In this study, small-sized gold nanoparticles < 5 nm, coated with two different natural ligand; Bovine Serum Albumin (BSA) and Glutathione (GSH) were applied in cancer treatment, by exploiting the physiochemical properties of them (size, surface charge and the chemistry of the coating ligand). Gold nanoparticles were prepared and characterized using Transmission Electron Microscopy (TEM), Scanning Electron Microscopy (SEM), Dynamic Light Scattering (DLS), Zeta potential, and UV–Vis spectrophotometer. The nano-complex (BSA- & GSH-AuNPs) was applied against three types of cancer cell lines; Rhabdomyosarcoma (RD), Murine fibroblast (L20B), and RAW 264.7 monocyte-macrophage (MQ), in addition to the normal line; Lymphocytosis cell, in vitro. The cytotoxicity effect of the complex was evaluated by MTT assay, after cells incubation with different concentrations of AuNPs (0.125, 0.25, 0.5, 1 mg/ml) for 24 & 48 h. Cells have been irradiated with continuous low power lasers; green (532 nm , 3.5 W/cm2) and Near-Infrared (NIR) (800 nm, 2.5 W/cm2) at 0.5, 1, 2 and 3 min separately, as photothermal therapy (PTT). One of the primary goals of successful treatment is reducing as possible as the risk and toxicity of the gold nanoparticles introduced into the human body. These goals can be realized by the active targeting of these nanoparticles directly to the cancer rather than normal cells. This targeting have been achieved by exploiting the GSH & BSA coatings as a [pH]-sensitive surfaces. They exhibit fast and reversible response to the [pH] variation conditions between normal (~ 7.4) and cancer cell (6 - 6.5). They would switch their charges from negative carboxylate to positive amine charges when penetrate the cancer cell, leading to localization and aggregation of AuNPs inside the cellular content. Results showed a considerable toxic impact via BSA- & GSH-AuNPs accumulation in cancer cells, alone and in combination with both the green and NIR laser irradiation, where toxicity more than 70% has been attained. Moreover, the results demonstrated that the smaller sized GSH-AuNPs (~3nm) exhibit more selective targeting and toxicity effect in cancer cells than BSA-AuNPs (≥ 3nm) at all nanoparticles concentrations, by the impact of the isoelectric point (IP) impact of GSH (~ 6) that is a near value of the [pH] of the cancer cell, in comparison with that of BSA (~ 5). Whereas no toxic effect has been investigated for normal cells. Another substantial targeting for cancer cells was by conjugating trans-acting activator of transcription TAT-Cell Penetrating Peptide (TAT-CPP) with BSA- & GSH-AuNPs. The binding efficiency of TAT-AuNPs was tested using Dynamic Light Scattering (DLS), UV–Vis spectrophotometer and Zeta potential. The nano-complex TAT-CPP (BSA- & GSH-AuNPs) was applied against cancer lines, in vitro. Cytotoxicity effect was evaluated again by MTT assay after 24 and 48 h incubation time for 0.125, 0.25, 0.5 and 1 mg/ml concentration. Results demonstrated that TAT-(BSA-AuNPs) exhibit significant toxicity for cancer cell lines. The effects of TAT-CPP have improved cancer cell reduction, where cytotoxicity more than 80% has been achieved. While after they irradiated by the two lasers, the toxicity reached to 90% especially at 3 min. TAT-AuNPs are emerging as a promising agent in the specific delivery and off-target eliminating. A proportionally relation of cellular death to AuNPs concentration, exposure time, incubation period and Light-to-heat conversion efficiency have been demonstrated. The efficiency of the cellular killing was featured distinctly at 1 mg/ml concentration, 3 min irradiation time & 48 h incubation period, at all experiment conditions. As a result , the small-sized AuNPs was a serious agent for developing the safety issues of photothermal cancer treatment by:  the selective targeting of the cancer rather than normal cells.  reducing the NPs toxicity by size overlapping with the renal clearance barrier of kidney filtration (~ 5.5 nm).  and promoting the photothermal performance in the NIR region, by the influence of size increasing via the self-assembly of the small AuNPs into large clusters, in which light penetration into deep cancer regions have more interested. This study promises to achieve the simplicity and facility in cancer therapy, where the small-sized AuNPs acts as a simple therapeutic tool for cancer diseases that target the deep, irregular, and complicated cancer regions in the human body, and could replace other cancer treatment techniques, even dispense the laser irradiation in the phototherml therapy.

Fabrication of Perovskite Solar Cell and Studying Some of Its Properties

By:Ali Kadim Hantoosh   Supervised By: Dr. Mohammed S. Mehde & Dr. Abdulnasser M. Al-Gebori   year: 2019

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In this work, compact Titanium dioxide (c-TiO2), meso-porous Titanium dioxide (mp-TiO2) and Methylammonium Lead Tri-Iodide (CH3NH3PbI3) films were prepared by spin coating method under different fabrication parameters of the CH3NH3PbI3 films. The aim of fabricating these films was to make perovskite solar cell. Many characterization measurements were achieved on the deposited CH3NH3PbI3 films in order to study the change that resulted from different parameters. The X-ray diffraction (XRD) measurements revealed that the lattice constants of the fabricated CH3NH3PbI3 films were close to the standard values when the films prepared at these parameters (annealing temperature of 100oC, rotation speed of 4000 rpm, spinning time of 60s and the anti-solvent was diethyl ether). The Atomic Force Microscope (AFM) measurements were conducted in order to study the morphology of the fabricated CH3NH3PbI3 films at different scale, these results showed that the grain size of the CH3NH3PbI3 films is in the range between about 160nm to 210nm. Moreover, AFM images showed that the most surface of the films had high degree of regularity and full coverage area. The field emission-scanning electron microscope (FE-SEM) results of the fabricated CH3NH3PbI3 films were well agreed to the AFM result especially in the grains shape and distribution. Absorption measurements have been done to determine the variation of the energy gap and absorption coefficient at different fabrication conditions of the CH3NH3PbI3 films. The structure form of the perovskite solar cells were FTO/c-TiO2/mp-TiO2/CH3NH3PbI3/Au. The capacitance-Voltage (C-V) measurements were achieved to determine the built-in potential, which found to have the highest value when using the Toluene as an anti-solvent during the synthesis of the perovskite layer. In addition, the Current density-Voltage (J-V) measurements in dark conditions have been conducted to compute the ideality factor and the saturation current, which are considered important parameters that influence the characteristics of the solar cells. The best solar cell efficiency was obtained at annealing temperature of 100oC, spinning time of 60s, spinning speed of 4000 rpm and anti-solvent of Diethyl ether with these parameters: Jsc= 12.188 mA/cm-2, Voc= 0.859 V, , FF= 0.57 and efficiency 5.85%.

Preparation and Characterization of Nano - Graphene Oxide by Hummer Method for Antibacterial Activity

By: Russel Rushdi Ghanim   Supervised By: Dr. Mohammad R. Mohammad & Dr. Adi M. Abdul Hussien   year:2019

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The graphene oxide (GO) nanosheets have been prepared by Hummer's method, which represents an easy and efficient technique. Alternations have been done to simplify this method to prepare the GO nanosheets with a novel way without a need to add sodium nitrate (NaNO3). Also this preparation has been achieved at room temperature without a need to water bath at temperatures of 35 °C and 98 °C. The structural, spectral, and morphological properties of the synthesis GO nanosheets were characterized by using XRD, EDS, Raman, FTIR, UV-Vis, FE-SEM, and AFM techniques. The x-ray diffraction (XRD) has been used to study the crystal structure of GO nanosheets, orientations, number of layers (sheets), and grain size. The GO nanosheets were observed, and identified by energy dispersive spectroscopy (EDS) analysis, which consist of carbon and oxygen atoms. Raman spectroscopy has been used to identify the ordered and disordered structure of GO nanosheets (functional groups). Fourier transform-infrared spectroscopy (FTIR) has confirmed the existence of the oxygen containing functional groups of the GO nanosheets. The ultraviolet-visible (UV-Vis) absorption spectrum shows two peaks, one in UV region and the other band in visible region, belong to the electronic transitions π→π*, and n→π*, respectively. In addition, the field emission-scanning electron microscope (FE-SEM) shows the morphology and the cross section of GO, which indicates that the nanomaterial takes the sheet shape (layer structure (2D)). II Moreover, the grain size of GO nanosheets has been measured by atomic force microscope (AFM) to be about 67.38 nm. The antibacterial activity of GO nansheets against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) were investigated for Gram-negative and Gram-positive bacteria, respectively. The well diffusion method, the colony forming units (CFUs) assay, minimum inhibitory concentration (MIC), morphological change, and the cell viability analysis by using florescent microscope, have been studied. It has been found that the lowest concentration inhibited the bacterial growth, were 125 μg ml-1 for E. coli and 62.5 μg ml-1 for S. aureus. The cell viability analysis was confirmed the damage, which has been occurred on bacterial nucleic acid for the two types of bacteria. The results of the present work offer a novel assay to prepare GO nanosheets, which could be used as novel antibacterial agent in future.

Wire Explosion Technique for Synthesis of Cu Nano Powder

By:Mustafa Mohammed Ridha Sabhan Al-waeli   Supervised By: Assistant Professor Dr. Sabah Habeeb Sabeeh & Chief Researchers Dr. Naseer Mahdi Hadi    year:2019

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In this thesis, for the first time in Iraq wires explosion technique for copper nanopowder production was constructed and developed, using Q-switch Nd:YAG laser with wavelength of (1064 nm) and pulse energy of (500 mJ) for ignited the explosion system. The technique has various features that make it different and superior to other techniques, it’s consume less time, high product rate, ecologically safe, efficient for prepared of nanopowders with high purity and large scale product. The development of ignition switch by laser ignition led to stabilization of pulsed current form through electrical discharge, improving instantaneous discharge and disposal of partial discharge phenomenon in capacitor, thereby improving characteristics of the nanopowder by this way, unlike the traditional method that used electric ignited in explosion technique. A nanopowder has been produced via this system using high purity copper wire (99%) with the dimensions (0.2 mm diameter, 30 mm length), under (2.25, 4, 4.5, 7, 8.3, 9.5, 9.6 kV) of explosion voltages and capacitors of (2.2, 4.4, 20 and 40 µF), inside evacuated chamber with ultimate pressure of (10-2 mbar) and then chamber filled with argon gas with ultimate pressure of (2 bar). The structural characteristics of the prepared copper nanopowder was characterized using X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Atomic Force Microscopy (AFM) and Energy Dispersed X-Ray Spectroscopy (EDS). X-Ray Diffraction (XRD) inspection was performed to obtain the structural information of the samples. The XRD results showed that the copper nanopowder has a polycrystalline structure with cubic system and the obtained peaks were a matching with standard values card. Scanning Electron Microscopy (SEM) inspection was also employed to study the surface morphology of the samples. The SEM results revealed the formation of homogeneous spherical and semi spherical nanoparticles with regular forms compacted with each other within very simple agglomeration levels which express the ideal state of particles shapes and sizes. These results were obtained only via dependence of the developed wires explosion technique with laser ignited in this thesis. Atomic Force Microscopy (AFM) inspection results showed existence of compacted small clusters of the prepared copper nanopowder. The highest value of roughness was (500 nm) for the Cu NPs sample which prepared by laser ignited wire explosion technique with 150 J and 8.3 kV, while the lowest value was (60 nm) for the Cu NPs sample which prepared by laser ignited wire explosion technique with 100 J, and 2.25 kV. The highest value of average diameter was (95 nm) for the Cu NPs sample which prepared by laser ignited wire explosion technique with 200 J and 9.6 kV and the lowest value was (21 nm) for the Cu NPs sample which prepared by laser ignited wire explosion technique with 200 J and 4.5 kV. Energy Dispersed X-Ray Spectroscopy (EDS) results showed that the produced copper nanopowder percentages at different energies were (98% at 100 J, 96.7% at 150 J, 97% at 200 J and 95.39%. at 490 J). The maximum absorption range (200-1100 nm) of Cu NPs was (52%) at explosion energy of 490 J and wavelength of 280 nm. The prepared Cu nanopowders had excellent reliability after one year of inspection.

Preparation and Characterization of PAni / Ferromagnetic/ Ferroelectric Composites for Electromagnetic Shielding Behavior

By:Jameel Mohammed Ameen Sulaiman   Supervised By: Assistant professor Dr. Sewench N. Rafeeq & Assistant professor Dr.Mukils M. Ismail    year: 2018

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The study search include preparing three components; conducting polymer (Polyaniline doped with Para toluene sulphonic acid) prepared by substance oxidative polymerization of aniline in aqueous medium with ammonium peroxydisulphate as an oxidant, ferrimagnetic cobalt ferrite (CoFe2O4) & cobalt-zinc ferrites (CoxZn1-xFe2O4) at (x= 0.5, 0.6, 0.7) prepared by (sol-gel) method and ferroelectric barium titanate (BaTiO3) performed in co-precipitation (wet-chemical) preparation method. The three components were thoroughly mixed in different ratios (9:1, 3:1, 1:1, 1:3, 4.5:4.5:1, 1.5:1.5:1, 1:1:2, 1:1:3) which is called ananocomposite, are widely used in favor useful of the absorption of large number microwaves in frequency range (8-12) GHz The as-synthesized light nanocomposites matter was characterized by X- Ray Diffraction (XRD), Atomic Force Microscope (AFM), Fourier transform infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM) and recently a microwave vector network analyzer (VNA) at 8-12 GHz. The mechanism of microwave absorption was obviously described with the help of real and imaginary parts of permittivity and permeability therefore the Nicholson–Ross–Weir method was applied to determine the real and imaginary parts of complex relative permittivity (εr'-jεr'') and permeability (μr'-jμr''). Results, of the samples with ratio weight (1:1) showed maximum absorption at frequency range (8-12) GHz. The reflection loss (R.L) showed for (cobalt ferrite / polyaniline) was (-28.35 dB) (>99.6 % power absorption) at 8.1 GHz, which was able to utilize as advanced radar IV absorbing materials. This value was decreased to (-9.1 dB) ( 88% power absorption) at 9.1 GHz and to (-9.6 dB) (>90% power absorption) at 11.2 GHz. i.e., the composite (cobalt ferrite / polyaniline) was suitable in life application for building or cell phone above 9 GHz. Result, of the (R.L) for the composite (cobalt-zinc ferrite / polyaniline) with ratio (1:1) was reversed from the previous one (-2.3 dB) (>40% power absorption) at 8.1 GHz, (-17.08 dB) (98 % power absorption) at 9 GHz, and (-24.86 dB) (99.73 % power absorption) at 10.9 GHz, therefore the composite (cobalt-zinc ferrite / polyaniline) was more useful in military applications as a shielding material. Results, for the composite (cobalt ferrite / barium titanate / polyaniline) with ratio (1:1:3) was the best than other their subgroup, (-5.47 dB) (>70% power absorption) at 8.1 GHz, (-8.37 dB) (>87 % power absorption) at 9 GHz and (-8.87 dB) (>90 % power absorption) at 11.6 GHz, but these results were still more less in power absorption than the composite (cobalt -zinc ferrite) with ratio (1:1). Results, of the composite (cobalt-zinc ferrite / barium titanate / polyaniline) with ratio (1:1:2) are completely different and the (R.L) have best values than all other samples research, it was (-5.56 dB) (>74% power absorption) at 8.1 GHz, (-17.75 dB) (>98 % power absorption) at 9 GHz and (-33.27 dB) (99.95 % power absorption) at 11.3 GHz, and these significance recorded maximum power absorption in microwave X-band which can be depended in different and wide application shielding; military applications such as radar absorption materials, in medical field, communications …etc. The means of microwave absorption is mostly owing to the dielectric loss quite than magnetic loss.

Characterization of doped and undoped Ni-Zn ferrite for super paramagnetic approach

By:Nasma A. Jaber   Supervised By: Dr. Mukhlis M. Ismail    year:2018

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In this thesis, there are two parts of preparation nickel ferrite nano-powder using Sol-gel auto combustion method. First: Zinc ions is substituted nickel ferrite according to the formula Ni1-xZnxFe2O4 where x was the ratio of zinc ions Zn2+ (x = 0, 0.1, 0.2, 0.3, 0.4 and 0.5). Second: lithium doped nickel-zinc ferrite with formulas {Ni0.9−2y Zn0.1LiyFe2+yO4, Ni0.8−2y Zn0.2LiyFe2+yO4 and Ni0.7−2y Zn0.3LiyFe2+yO4} where y is the ratio of lithium ions Li+ (y = 0, 0.01, 0.02, 0.03 and 0.04). The structure, morphology, elastic, dielectric and magnetic properties were studied via X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), Fourier transform infrared spectroscopy (FTIR), Inductance-Capacitance-Resistance (LCR) meter and vibrating sample magnetometer (VSM). X-ray diffraction results showed that the prepared spinel ferrite had cubic spinel structure with space group Fd-3m. The experimental values of the lattice constant (aexp) were increases from 8.34 to 8.397 Å with the addition of zinc ions but it was decreases with doped Li ions. It was found the decreasing of the crystallite size with addition of zinc and lithium ions concentration. The radius of tetrahedral (rtet) and octahedral (roct) site, oxygen position parameter (U) and jump length (J) were computed from cation distribution. FTIR measurement exhibit two absorption bands (ʋ1 and ʋ2) around 400-600 cm-1 which confirms the existence of tetrahedral and octahedral sites of ferrite. The force constant, elastic wave velocity, bulk modulus and young's modulus are reported. It was found that the values of the calculated elastic constant for Ni-Zn ferrite nanoparticle in a good agreement compared with those of bulk material. The dielectric parameters [dissipation factor (Df), the dielectric constant (Ԑ') and ac conductivity (σac)] of spinel ferrite nano-powder had been measured. There were decreases by increasing frequency for spinel composite. The saturation of magnetization, remiensis, coersivity, the magnetic moment, anisotropy constant and permeability were found from hysteresis loop. It was found that the value of saturation magnetization for nickel ferrite is equal to (Ms =46.8 emu/gm). This value increases when addition zinc ions and became maximum at x = 0.3 (Ms =59.64 emu/gm) and then decrease. The saturation magnetization and coercivity varied from (Ms= 13.9 to 67.56 emu/gm) and (Hc=65 to 133 Oe) for lithium doped Ni-Zn ferrite. The obtained values of squareness ratio (Mr/Ms) were varied from 0.09 to 0.36 this means that the preparation material have single domain structures. The prepared sample (Ni-Zn ferrite with x=0.5) and (Li-Ni-Zn ferrite at x=0.3, y=0.04) suitable for superparamagnetic applications which have low coersivity and crystallite size.

Synthesis and Study the Structural and Optical Properties of TiO2 Nanorod Arrays Decorated with CdS Nanoparticle

By:Natheer Jamal Imran   Supervised By: Prof. Dr.Mohammad R. Mohammad & Asst. Prof. Dr.Selma M.H. Al-Jawad   year:2017

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In this work TiO2 nanostructure thin films were prepared using different deposition methods (chemical bath deposition, hydrothermal, and anodization). Many growth parameters have been considered in this work to specify the optimum condition, for CBD namely (pH, deposition time, and concentration), different deposition times for hydrothermal method, and for anodization technique different electrolytes solutions were used. Annealing in air at different temperatures of (400,500, and 600) °C at constant time (1 hour) were achieved for all films deposited by different methods. The structure and morphology of (XRD, SEM, EDX, and AFM), and optical (UV-Visible spectroscopy, PL spectroscopy, and Spectral Response), properties of nanostructures TiO2 films were investigated and analyzed. XRD analysis of all deposited films has confirmed the formation of polycrystalline-tetragonal phase (anatase, and rutile) with increasing in crystalline size, with increasing annealing temperatures. As a result; it has been found that all films have nanostructures nature. SEM measurements of all TiO2 films show nanostructure shaped (films deposited by CBD show nanorods shapes, films deposited by hydrothermal method show nanofibers shapes, and films deposited by anodizatin technique show nanotubes shapes. EDX analysis confirmed the stoichiometry ratio between Ti, and O to be 1:2 to produced TiO2 film. Optical measurements (absorbance, and energy band gap) were carried out. All absorption edges are located at UV-region, and Eg has higher values compared with Eg for bulk TiO2 film. PL measurement results show two peaks one located at UV-region pointing to energy band gap for TiO2 films; second one is located at visible region pointing to impurities in films. Spectral response measurements show photocurrent peaks for all TiO2 structure films deposited by different methods centered at UV-region. Second step is depositing (decorated) CdS NPs layers on TiO2 films deposited by two methods CBD, and successive ionic layer adsorption and reaction (SILAR) (with 1, and 10 cycles), to synthesize TiO2/CdS core-shell composite films. XRD analysis of all deposited films has confirmed the formation of two phases one is tetragonal phase (anatase, and rutile) for TiO2, and second hexagonal phase which belong to CdS layer. SEM images show change in morphology of CdS from rose like shape to spherical grained CdS particle. And for all films the nanoparticles cover all TiO2 films. For optical measurements, all absorption edge values for TiO2/CdS films showed red-shifted towards visible region, and Eg has decrease in values compared with TiO2 nano structure films. An example of the value of Eg for TiO2/CdS (CBD/CBD) was about (2.9) eV, and this mean film absorbs in visible region besides UV-region. PL measurement results of TiO2/CdS core-shell show two peaks, one is located at UV-region pointed to energy band gap for TiO2 nano films, and second one is located at visible region pointing to recombination of photogenerated electron–hole pairs within CdS layers. Spectral response measurements show photocurrent peaks for all TiO2/CdS films deposited by different method have red-shift to visible region and this result improves of successive composites between TiO2 and CdS. Finally using TiO2, and TiO2/CdS core-shell nano composite films prepared by different methods as photoelectrods device. This application was performed by using a standard three-electrode photoelectrocatalytic cell, the PEC measurements involves current-voltage (I-V) characteristics under darkness and under illumination (with UV-light source, and UV-Visible light source). The result for TiO2 films shows that all prepared films by different methods highly responses to UV-light source. And the higher response to UV-light was getting by using TiO2 film prepared by anodization technique with (HNO3+HF) electrolyte solution. For TiO2/CdS core-shell films we find that all films highly responses when illuminated of UV-Visible light source. This result is ensured the successful composite between TiO2 nanostructure and CdS NPs, because the film become absorbance the incident light located in visible region besides UV region. The higher response to UV- Visible light was getting by using TiO2 NRAs/CdS NPs film prepared by (CBD/CBD).

Synthesis of (Au) Nanoparticles with Porous Silicon for Sensor Application by Different Methods

By:Intisar Mohammed Khudhair   Supervised By: Prof. Dr. Uday Muhsin Nayef    year: 2017

Abstract

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In this work, porous silicon (PS) layer is prepared by electrochemical etching (ECE) approach using p-type silicon (100) orientation, with resistivity 1.5-5Ω.cm. The etching solution consists of HF (20%) and ethanol, at different current densities 5, 15 and 25 mA/cm2, and etching time of 15min. Morphology, structural and chemical properties studied by Atomic Force Microscopy(AFM), X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy respectevely. XRD investigation is appeared broad a diffraction peak when the size of crystal becomes inside nanometer . Reflectivity for bulk Si and PS layer prepared at 15 mA/cm2, etching time 15 min and HFc 20% is investigated. The photoluminescence PL for the sample is determined in air and different organic chemical vapor such as Ethanol, n-Hexane and Trichloroethylene and CO2 gas. Gold nanoparticles (AuNPs) have been prepared by laser ablation technique of gold target submerged in double distilled deionized water (DDDW) at different laser energies 160, 300, 460 and 600 mJ at 500 pulses number of pulse, using Nd:YAG laser at 1046 nm . AuNPs deposited on PS were prepared at 15 mA/cm2, with etching time 15 min and HFc 20%, by drop casting (5 drop). The Morphology and structural properties for AuNPs/PS is studied by AFM and XRD respectevely while, FTIR techniques confirmed the presence of Si-Au bond AuNPs were prepared by chemical reduction (seed-growth-methods) . The size of nanoparticle depends on the amount of seed added to growth solution. after that using solution by adding to solution etching where the solution consist of (HF+Ethanol+AuNPs) also PS prepare by electrochemical etching.the properties of samples AuNPs:PS such as The morphology characteristics investigated by AFM and the structural properties by using XRD, FTIR characterization techniques proved Si-Au bond. PL spectroscopy for AuNPs/PS and AuNPs:PS revealed that the intensity increase compare with PS layer alone where is depends on amount of AuNPs and effected by organic vapor chemical and CO2 gas where the PL intensity decreased (PL quenching) when exposed to this organic vapor and gas. [ii] PL quenching in the presence of organic vapor was found by decreasing radiative recombination of exciton that happen under the effect of the dielectric constant of the medium, and in CO2 PL is quenched because the absorption of CO2 increase the concentration of holes at surface. The injection of hole into valance band of porous silicon cause nonradiative decay of the excitation responsible for the extent of PS PL. Sensitivity of samples PS , AuNPs/PS and AuNPs:PS for CO2 gas study by the effect of the gas on electrical properties curve I-V found the current increased when exposed to gas because of the increase of the hole. The sensitivity of samples contained AuNPs is higher than samples of PS alone.

Detection of Some Dangerous Materials Via Raman Spectroscopy Technique

By: Haider Gheni Abdulzahra   Supervised By: Prof. Dr. Mohammad R. Mohammad & Dr. Naseer M. Hadi   year:2017

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In this work a standoff Raman spectroscopy system has been designed to detect dangerous materials (Cyclotrimethylene-trinitramine C4, ammonium nitrate AN, trinitrotoluene TNT and urea nitrate UN) in dark laboratory at 4 m distance. The standoff Raman spectroscopy system employs frequency doubled Nd:YAG laser at 532 nm excitation with laser power of 250 mW and integration time of 2 s. The telescope was coupled to the Raman spectrometer using a fiber optics cable, and notch filter which is used to attenuate Rayleigh scattered light. The Raman scattered light is collected by a telescope and then transferred via fiber optics cable to the spectrometer and finally directed into CCD detector. In order to test standoff Raman spectroscopy system, it has been used to detect the spectra of toxic industrial compounds (TIC) such as acetone, toluene, and carbon tetrachloride. The standoff Raman results were compared with conventional Raman microscopy results using a bench top Bruker SENTERRA Raman instrument. The effect of integration time and laser power on Raman signal is studied. Standoff Raman detection of C4 substance at 4 m distance under partially illuminated environment was achieved and hence the effect of higher integration time was studied under the same condition. In order to test the capability of standoff Raman system of detecting explosives trace, detection of C4 and AN explosives have been achieved with limit of detection (LOD) of 20 µg for C4 and 40 µg for AN. Solid explosive samples were located on glass slides, aluminum plates and aluminum foil, while liquid samples were transferred into 3.5 mL quartz cuvette. Both types of samples were placed at a distance of 4 m from the telescope.

Preparation and Investigation Study on (CuO/H2O) Nanofluid for Improving the Performance of (PV/T) Hybrid System

By:Hadia Kadhim Judran   Supervised By:Assist. Prof. Dr. Sabah H. Sabeeh & Assist. Prof. Dr. Hashim A. Hussein    year:2016

Abstract

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Nanofluids are innovative and efficient class of heat transfer fluids. These fluids have unique thermal properties over the conventional fluids or base fluids such as water and ethylene glycol with long- term stability. The main goal of this study is synthesis of advanced coolant of nanofluid with enhanced thermal conductivity, high stability, low cost, different volume concentrations, and suitable for using it in cooling technique to improve the electrical and thermal performance of photovoltaic/thermal (PV/T) hybrid system. Therefore, CuO/deionized water nanofluid was synthesized via two-step technique. This technique is selected based on its good features, where it is economical and suitable for the production of oxide nanofluids in outsized scale. In first step, CuO nanopowder is prepared by a coupled chemical method using sol-gel/hydrothermal processes. The Sol-gel stage is carried out at room temperature in alkaline medium at pH=9. The product of first stage of coupled chemical method namely sol-gel process is treated hydrothermally through second stage in stainless steel autoclave at temperature of 160˚C for 3 hours. The products of two stages were characterized by using different techniques. The results of XRD technique proved that the product of sol-gel process (first-stage) is a nanocomposite of Cu(OH)2/SDS. High degree of crystallinity is obtained after hydrothermal treatment of Cu(OH)2/SDS. According to the XRD patterns, this nanocomposite material is totally converted to pure phase of polycrystalline copper oxide with monoclinic crystal structure by dehydration reaction during the second stage. The same results are confirmed by FT-IR measurements. Formation of two components is also confirmed by EDX quantitative analysis. FE-SEM measurements explained that the nanocomposite of Cu(OH)2/SDS has irregular layer-like structure, while CuO morphology is revealed a unique complex nanostructure. CuO nanopowder with prolate spheroid morphology is constructed from numerous numbers of very tiny nanoparticles as nano building units. The size range of these nano building units was (15-25nm). Based on the above results, growth mechanism of CuO nanopowder was demonstrated. The effect of Cu precursor molarity is studied in the range of (0.02-0.25M). The results showed that the impact of this parameter is related to size of prolate spheroid, purity of the yield, and quantity of the produced CuO nanopowder, but it has a slight impact on the average particle size of nano building units. II The optimum sample of CuO nanostructure was obtained by SDS concentration and Cu precursor molarity of 0.25M and 0.2M, respectively. FE-SEM analysis of optimum sample revealed that the size of complex nanostructure of CuO prolate spheroid was about (160-630nm) according to the measurement of major axis and about (125-325nm) according to the minor axis of prolate spheroid shape. The stability of CuO nanofluid was tested by two techniques; Zeta potential measurement and sedimentation or visual test. The results showed that the good stability of the optimum sample is devoted via surface electrical charge of (-48.29mV) and stability of dispersion behavior over more than 3 months. TEM and HRTEM results confirmed that the nano building units of CuO prolate spheroid have narrow distribution of nanoparticle sizes. The average particle size of (15.473nm) agreed very well with that calculated by structural information from XRD spectrum using Scherrer formula. In the second step, the mechanical approach was used to confirm the stability of CuO nanofluid with different volume concentrations. Thermophysical properties namely thermal conductivity, viscosity, specific heat capacity, and density were measured for CuO/deionized water with volume concentrations of 0.05, 0.1, 0.15, 0.2, and 0.25vol.%. The obtained results showed that all thermal properties of CuO nanofluid are improved with increased solid content of CuO nanopowder within the base fluid. The important property in heat transfer applications viz thermal conductivity revealed evident enhancement with increasing volume concentration of CuO nanofluid. The ratio of thermal conductivity enhancement (Knf %) is ranged from 4.49% to 32.945% for both lower volume concentration (i.e. 0.05 vol. %) and high volume concentration (i.e. 0.25 vol. %), respectively. The water cooling technique was designed for cooling the solar panel with surface area of about (1.81m2), which consisted of a heat exchanger and deionized water circulating through copper pipes with different mass flow rates of 1, 2, 3(L/min). The electrical performance of PV panel was recorded over a period of time from 7:30AM to 2:30PM as a function of solar irradiation intensity and temperature of PV panel surface. The results indicated that the electrical efficiency decreases from 9.1% to 2.7% when the PV temperature increased from 37.2˚C to 69˚C, respectively. By using deionized water as working fluid in PV/T system it was found that the optimum mass flow rate is 3(L/min) and the thermal gain is 3.9˚C at the end of period time of 2:30PM. Efficient cooling was III obtained by using CuO nanofluid as working fluid in PV/T hybrid system with different concentrations namely (0.05, 0.1, 0.15, 0.2, and 0.25vol. %) at mass flow rate of 3(L/min). The operating temperature of PV panel dropped significantly from 64.2˚C with deionized water cooling to 55˚C with cooling by CuO nanofluid at concentration ratio of 0.25vol.%. All the electrical characteristics of PV panel were linearly improved with increases in the volume concentrations ratios of CuO nanofluid. At optimum volume concentration of 0.25vol.%, the maximum enhancement in electrical efficiency of solar panel relative to that in case of water cooling about 47.65%. All the unique results are attributed to the high ratio of surface area to volume of CuO prolate spheroid within the base fluid. It is worth noting that up to now, preparation of pure phase with unique morphology as flower-like and prolate spheroid of CuO nanostructure without the need to the heat treatment after preparation process is very limited. Using the advanced and complex nanostructure for production of oxide nanofluid is a new contribution in the field of nanofluids synthesis. In addition, for the first time that CuO nanofluid is used in cooling system of PV panel. These aspects of this work are novel.

PREPARATION AND STUDY NANOMAGNETIC PROPERTIES OF Co-FERRITE

By:ZAHRAA SALAH AHMED   Supervised By: Asst. Prof. Dr. SABAH H.SABEEH   year:2016

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In this work the Nano-magnetic materials (cobalt ferrite) with formula (CoFe2O4) as nano- powder was prepared from (Ferric Nitrite, Cobalt Nitrite and Citric Acid) by utilizing sol-gel auto combustion method, with different pH(3,5,7), then the powder were calcined at different temperatures(300,500,700)°C, and the samples sintered at different temperatures(1000,1100) °C. The structure, physical, mechanical, dielectric, and the magnetic properties of these samples were studied. The crystallite size (D) and the lattice factor (a) rise as the temperature rise, while X- ray density (ρx) decreases when the temperatures increase ,this word is compatible on samples with pH (3,7) ,but this behavior is different at pH (5). The images of (AFM) showed that a uniform structure without any valleys was observed and all the particles are aliened vertically due to the homogenously distribution of the ferrite particles. The dielectric constant of all samples which sintered at temperatures (1000, 1100) °C decreases with increasing frequency and also we show that the dielectric constant is highest at the frequency of (25) kHz and it lowering with the growing of hesitation in whole the specimens. The saturation magnetization (Ms) , Residual Magnetization (Mr), and Remanence Ratio(R) seem to increase with the increasing calcining and sintering temperatures ,at the same pH(7),while the coercivity (Hc) decreases with the decrease in the particle size, because there is a direct relationship between the coercive force and the particle size. The Relative permeability (µr) increases with increasing the calcining and sintering temperatures except the samples with pH (5). Finally, It is found that the samples with pH (7), at calcining temperature (700) °C, and at sintering temperature (1100)°C, have a good properties, which can be utilized in many applications.

EFFECTS OF DOPING, ANNEALING, AND DIFFERENT CHEMICAL METHODS ON THE CHARACTERISTIC OF NANO-STRUCTURED SnO2 THIN FILMS FOR GAS SENSOR APPLICATIONS

By:AMEL SAJIT SABER   Supervised By: Asst. Prof. Dr. SELMA MOHAMMED H.AL-JAWAD, Dr. ABDULHUSSAIN K. ELTTAYEF    year:2016

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In this work nanostructured SnO2 thin films were prepared by using sol-gel (dip and spin) coating and chemical bath deposition techniques on glass substrate with (300 ± 20) nm thickness, which are simple and inexpensive techniques suitable for deposition of large area in different shapes. To indicate the best condition many parameters have been considered, namely annealing temperatures (300, 400, and 500ºC) at constant time of 60 minutes and Cu-doping concentration (2, 4, and 6) wt.%. Structural, optical and electrical properties of nanostructured SnO2 thin films were investigated and analyzed briefly at different conditions. Structure and surface morphology of nanostructured SnO2 films were characterized by using X-ray diffraction, atomic force microscope and scanning electron microscope measurements and transmission electron microscope. The optical properties of nanostructured SnO2 thin films were studied, such as transmittance, absorption coefficient, photoluminescence, and optical energy gap for different annealing temperatures and doping concentrations. The electrical properties of SnO2 thin films include D.C electrical conductivity and Hall effect which shows that the type of films is (n- type) semiconductors for different parameters, it is noted that the electrical conductivity increase with increase in annealing temperature and doping concentration for all films prepared. The gas-sensing SnO2 films fabricated via these techniques (dip, spin coating and chemical bath deposition ) for CO and NO2 gases in concentration of 50 ppm at R.T and 50 ºC were measured, the value of sensitivity is (23, 32) %, (28.5, 36.5) %, (32.83, 40.22) % respectively . The results show that the films prepared by CBD technique with 6% Cu doping. The undoped and doped tin dioxide films are a good sensor for CO and NO2 gas. The sensitivity proportional directly with the annealing temperature for limited range. In general the sensitivity increases by increasing the concentration of Cu. The results revealed that the procedure of film preparation plays an essential role in the design of sensors and getting high sensitivity.

Synthesis and Study the Structural and Physical Properties of Nano-BaTiO3

By:Mojahid Mohammed Najim   Supervised By:Asst.Prof.Dr.Sabah M. Ali Ridha    year:2013

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At room temperature and normal pressure, Barium titanate (BaTiO3) and Barium Lanthanum titanate (BaLaTiO3) powders were prepared via a semi-oxalate method that uses barium oxalate and TiO2 precursors, instead of titanyl oxalate, in a solution pH adjusted around 5.5, the precursor this completely transforms into BaTiO3 at 920 oC. Nanometer size BaTiO3 crystallites are produced during this synthesis due to the lower calcination temperature. Nanoparticles of Barium titanate powder having a diameter of about 65 nm, was studied using several experimental techniques for the determination of the crystalline phases and purity of synthesized BaTiO3. The results of XRD ,FTIR and SEM spectroscopy analysis were contradictory with respect to the nature of the formed phase for the barium titanate nanocrystals. The first indicated the formation of a cubic phase and the second indicated that it was tetragonal. Thus, we use a combination of both (pseudo cubic and slightly tetragonal phases). The doping effects of La3+ on BaTiO3 powder ( Ba1-XLaXTiO3 , where ( x = 0.005, 0.015, 0.02, 0.025 ), where ( x ) was the volume ratio with respect to the structural were studied (XRD, FTIR and SEM spectroscopy analysis) . Owing to the replacement of Ba2+ of larger ionic radius with the dopant La3+ of smaller ionic, lattice parameter decreased slightly with increasing La content. The electric and dielectric properties for polymer/nanoceramic composites, polymer/BaTiO3 and polymer/Ba1-XLaXTiO3 where ( x = 0.005, 0.015, 0.02, 0.025 ), where ( x ) was the volume ratio and polymer(unsaturated polyester resin(UPE)), were studied in order to see the Interaction ferroelectric material(BT) and rare earth element (La) with the polymer component (UPE). Both the permittivity and energy loss of the encapsulated -BT or B1-XLXT composites showed lower values because the polarity of the hydroxyl groups on BT or B1-XLXT were suppressed physically by the UPE molecules. Therefore, polymer encapsulation of BT or B1-xLxT plays an important role in controlling the dielectric constants of the composites. We used the Bruggeman rule of Mixture to calculate eff ε which is the effective permittivity of the nanocomposite. Real dielectric constant decrease with increase (x) value for B1-xLxT, because the doping by La3+ brings more electrons into the system, increases the dielectric constant up to a critical doping level and the material changes from insulator to n-type semiconductor and back to insulator, means that the electronic contribution induced by La-doping can be charge compensated by B cation vacancy and/or reduction while creating oxygen vacancies and thus should be responsible for semi-conductivity.

Synthesis and Characterization of Graphene

By:Adi M. Abdul Hussein    Supervised By: Dr. Salam H. Ali & Dr. Hilal S. Wahab    year: 2013

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Graphene, a single atomic layer of hexagonally arranged sp2–hybridized carbon atoms, with a thickness of only 0.34 nm, exhibits unique properties. The current interest in graphene can be attributed to three main reasons. Firstly, various forms of graphite, nanotubes, buckyballs and others can all be viewed as derivatives of graphene. Secondly, the scalability of graphene devices to nanodimensions makes it a promising candidate for applications in nano-devices. Thirdly, its electron transport properties are described by the Dirac equation which allows access to quantum electrodynamics in a simple condensed matter experiment. Among the different methods to produce graphene sheets by exfoliation of graphite, the electrochemical route has been very scarcely investigated. The electrochemical exfoliation of graphite represents a simple one-step method to produce graphene sheets in ionic liquid/water mixtures where hydroxyl and oxygen radicals produced by anodic oxidation of water start the oxidation of the edge planes of graphite, facilitating intercalation of an ions from the ionic liquid. The resulting graphene samples were characterized by, light optical microscopy, TEM, XRD, Raman spectroscopy, Ultraviolet and visible absorption spectroscopy. The XRD pattern of graphene film contains a sharp and intensive peak at 2θ = 26.1782°. The basal spacing of the graphite was increased from 3.35Å to 4.301 Å in the reduction of graphene oxide. This result indicates that the direct reaction of graphite particles with aqueous solution can be proposed as another route for the exfoliated graphite having excellent physical properties. Raman spectroscopy is employed to study various samples. Our calculations show that the, the lateral sizes La = 6.324nm, The intensity ratio IG/I2D of the product is ~1.59 and I(D)/I(G) ratio ~0.6957. As in the absorption spectrum has been calculated energy gap delegation was identical to our theoretical in Annex.

Studying Some Physical Properties Of Zn2xCu1-xIn1-xS2 thin Films Prepared by Chemical Spray Pyrolysis

By: Yousif Abid AL -Shaabani   Supervised By: Prof. Dr. Ala Alden Al-Naimi & Assist . Prof.Dr.Hamid Al-Jumaili    year:2009

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Thin films of Zn2xCu1-xIn1-xS2 (ZCIS) with various values of X ={0,0.1,0.2,….and 1} , have been prepared by spray pyrolysis on glass slides (25mm ×25mm) substrate at temperature (Ts) of 350 ±10oC . The thickness of thin films are 400 ±20nm . The obtained results of x-ray diffraction (XRD) structure analysis was polycrystalline for all values of X. When an amount of Zn atoms added to the compound a new phase structure was formed which is a mixture of chalcopyrite and zinc blende . This new phase continues until x=0.5 , after that it shifted toward zinc blend structure . The morphology of the prepared thin film surface showed a superstructure when Zn was added and gives more roughness . The optical characteristics of Zn2xCu1-xIn1-xS2 thin films have been investigated by UV – VIS spectrophotometer in the wavelength range (300 -1000nm ) . The films have a direct allow electronic transition with optical energy gap ( Eg ) values varied between 1.58- 3.5eV depending on X value. Therefore the ZCIS films are promising in thin film solar cell applications . The maximum value of the refractive index (n) for all thin films is obtained to be 2.7 in the visible region . The dependence of extinction coefficient (K ) value on the film structure was found. So it gives two minimum value at two wave lengths , this means there are different absorption mechanisms . The maximum value of real dielectric constant is about 7 for all values of X . But the value of imaginary part ( Є2 ) was changed with X value. Also the tail width ( Et ) in the energy band is calculated to give a maximum value at X =0 , which equal 0.45 eV and decreased to 0.18 eV , this means that Zn gives good crystallinity and different structure than CuInS2 . The electrical properties of Zn2xCu1-xIn1-xS2 thin films were investigated . Hall experiment results an evidence of a p-type conductivity from X =0 to X =0.8 and n-type conductivity for X =0.9 and X =1 . The D.C conductivity ( σ D.C) was increased to a discrete limit temperature and then it becomes nearly constant with temperature . The films appeared to have one or more activation energy ( Ea) depending on X values . This means that there are many mechanisms the conductivity . The I-V characteristics at dark and illumination of ZCIS thin films were investigated , it was found that Id and Iph increase with (V),and the values of Iph were greater than Id for all films . Also Id and Iph found to depend on X value . The variation of Id and Iph with wave length ( λ ) gives Iph greater than Id for all thin films and the maximum value of Iph was at X=0.5 . The maximum photosensitivity occurs in the wave length between (500-580) nm . The ZCIS thin films are photosensitivity with laser He-Ne and semiconductor laser.

Modeling of Organic Solar Cells Parameters for Efficient Performance

By:Wisam Abdullah Latif   Supervised By: Assist. Prof. Dr. Dayah. N. Raouf   year: 2009

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Although the efficiency of organic solar cells is not yet high enough to be competitive with inorganic solar cells, but it has certainly increased significantly to reach about 5% at present. To gain better insight into the interplay of the various critical parameters that influence the performance of organic solar cells, we have built up a numerical model for the electrical characteristics of bulk heterojunction (BHJ) solar cells relating their performance to basic physics and material properties such as charge carrier mobilities. This model is based on the metal-insulator-metal (MIM) picture, as it describes the generation and transport processes in the BHJ as if occurring in one virtual semiconductor. Drift and diffusion of charge carriers, the effect of charge density on the electric field, bimolecular recombination, and a temperature- and field-dependent generation mechanism of free charges are incorporated. By using values as close as possible to published experimental ones, the experimental current-voltage characteristics are regained. We demonstrate, using our model, that the balance between the carrier losses by extraction and recombination leads to a distinct optimum in the carrier mobility with regard to the efficiency of organic solar cells. For low mobilities recombination losses limit the performance, whereas the efficient extraction at high mobilities leads to a reduction of the open-circuit voltage (V_oc) and consequently drop in the efficiency. Space charge limitations in organic solar cells have been studied, on bases of which an analytical relation for the conversion efficiency is predicted. Numerical modeling on suitable BHJ system have confirmed that the intensity dependence of the short circuit current (J_sc) is governed by space charge rather than by bimolecular recombination alone. Calculations based on the model presented in this work confirm that decreasing polymer's band gap, which leads to an increase of the amount of photons absorbed by the film, would indeed increase the performance of solar cells. However, we demonstrated that combining this effect with the effect of minimizing the energy loss in the electron transfer from the polymer to the acceptor phase would enhance the performance even more. We concluded that the efficiency of BHJ solar cells can reach a value of more than 10%, provided that; the band gap of the polymer is between 1.9 and 2.0 eV, balanced carrier transport(μ_p≅μ_n ), and an active layer thickness is between 150-200 nm.

Crystal Structure and Morphology of Nano Ba(Zr,Ti)O3 Prepared Using Hydrothermal Method

By:Mukhlis M. Ismail   Supervised By: Dr. Sabah M. Ali & Dr. Ziyad S. Ahmed    year: 2009

Abstract

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Nanocrystalline Barium Zirconate Titanate BaZrxTi1-xO3 (x=0 (BaTiO3 or BT), x=0.001 (BZT1), x=0.008 (BZT2), x=0.027 (BZT3), x=0.064 (BZT4) and x=0.125 (BZT5)) were prepared hydrothermally using TiCl4, ZrOCl2.8H2O, Ba(OH)2.8H2O and NH4OH as starting materials at 150oC for 2h. The structure of the prepared nanocrystalline BT and BZT powders were a metastable cubic perovskite according to XRD, DSC and HRTEM analysis, while FT Raman spectra showed that BT and BZT with Zr content less than 0.8% have a tetragonal structure. The volume of unit cell of the prepared powders were 64.96, 65.013, 65.086, 65.3, 65.59Å3, and 66.28 for BT, BZT1, BZT2, BZT3, BZT4 and BZT5, respectively while it shrinked after annealing powders at 500 and 700oC and became close to standard at 1000oC. Hydroxyl and carbonate groups were observed in all prepared powders that showed in FTIR spectroscopy as a vibrational band at 3200-3600cm-1 and 1447cm-1, respectively. Most of hydroxyl groups which were observed in TG analysis refer to surface absorbed water, therefore the amount of hydroxyl groups which was shown in TG (1.725%) was greater than that shown in XRF (0.3638%) results. The crystallite size of BT powders have increased with the increase of annealing temperature from 19nm at room temperature to 70nm at 1000oC, while for BZT this range reduces with the increased Zr content. According to FTIR spectroscopy at different annealing temperatures, the hydroxyl groups were expelled less than 600oC while carbonate groups needed more than 700oC. The prepared powders have converted to a tetragonal phase after annealing at 700oC for BT and more than 700oC for BZT1 and BZT2 only. Contrast variations across particles were observed by TEM images which indicated the presence of high strain inside the BZT lattice. TEM image showed a dendrites shape for BT and showed spherical shape for BZT. Well- crystallized, and single crystal nature was shown in all powders as revealed by a SAED and HRTEM analyses. These analyses showed also that the surrounding edges of the particle are very smooth with no surface steps. For prepared BT powders, small nucleated islands with thickness about 5nm were observed at the edge of the particle.

Characteristics of Polymer Composite Materials Waveguide

By:Latef Mohamed Ali   Supervised By:Dr. Mahdi Hassan Suhail & Dr. Nabeil Ibrahim Fawaz    year:2009

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Finding suitable polymer composite materials for the transmitting of X-band frequencies in the range 8-12 GHz, are useful for communications. In this work, we describe the simulation characterization of composite waveguide components, PS/Alumina , ABS /Barium titanate ,Barium titanate/ EPDM and zirconium tin titanate / epoxy. The detection limit of a complete numerical solution of Helmholtz equation for composite waveguide has been determined. A computer program was used to calculate the propagation constant and field patterns of the modes in a waveguides. The effect of the slab thickness and applied frequencies on the propagation characteristics and the number of the modes were investigated. The electric fields within the dielectric slab waveguide, were used to calculate the transmission coefficient of the dominant and fundamental modes. This was implemented in MATLAB program, and the numerical values for the modes of propagation were obtained. A good correspondence between number the of modes and the cut off thickness was found. The transmission of microwave depend on the slab thickness and the frequencies was investigated, and the calculation of the transmission coefficients was obtained. It has been found that varying the refractive index and the frequency has a much large effect on transmittance. It should be mentioned, that the normal-incident transmission coefficients have been calculated in this work. The transmission for the samples under the study were varied from zero to a maximum value (100% ) . This study demonstrates the feasibility of obtaining composite waveguide as a low-loss, single-mode transmission and useful for designing a waveguide filter. Ultralow-loss lines are possible by reducing the thickness of the slab of the samples.

Preparation and Studying Some Physical Properties of Polycrystalline PbI2 Films

By:Shatha Shammon Batros Jamil   Supervised By: Dr.Ali M. Mousa. Alzuhery   year: 2008

Abstract

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Lead iodide is one of the most important materials which is used in x- ray detectors. It is prepared from the chemical reaction of (0.01M) Pb(NO3)2 with (0.05M) KI . Some of tests have been carried out to determine the presence of other materials in lead iodide. Thick films were deposited from lead iodide on glass by solution method. This method has a low cost and fast preparation which is produce a large area with appropriate designed thickness without need to complex techniques or assistant agents in a comparison with other methods. The present study of deposited film focused on structural, electrical and optical properties. Also this research studies the effect of doping on the physical properties of lead iodide with different dopants at different weights, annealing temperatures, where it used with dopant material which are Barium nitrate and Holmium oxide with (0.002gm,0.005gm,0.007gm) weight and in annealing temperature from 50oC to 200oC. The x-ray diffraction diagram shows polycrystalline hexagonal structure with four peaks which correspond to (001),(002),(003),(004) reflection planes. It is found that peaks intensity change with doping and annealing processes, Some structural properties such as grain size, micro strain ,shape factor, number of layers as a function of dopant weights and annealing temperatures were calculated. The electrical measurement shows that the electrical conductivity of lead iodide films is (0.99*10-9 Ω-1.cm-1) at dark , and (1.34*10-7 Ω-1cm-1) under light. The ratio of light conductivity to dark conductivity =135 at room temperature and at 100oC for one hour it increases to reach 331.08, then decreases sharply with increasing dopant weight and annealing temperature to reach 150 oC to 164 and 82.66 for both Ba , Ho respectively .The activation energy was calculated and its values between 0.0493 to 1.125 eV. The Hall measurements show the influence of compensation effect of dopant weight and annealing temperature and it was found that Barium of great effect in compensate than Holmium . The optical data were analyzed and interpreted in terms of direct electrical transitions. Transmission spectrum of undoped lead iodide exhibits a sharp increment starting from around (520nm) and becomes sharper with doping and annealing processes. It is found that absorption coefficient has a high values. It was observed that pure lead iodide has a wide direct band gap of values (2.305eV), This energy gap is affected by doping and annealing. The higher spectral response for PbI2 is at wavelength between 480-500nm.

Preparation and characterization of some physical properties for Copper and Copper alloys –SiC Composites

By:Samir Bahjet younis   Supervised By:Dr. Ziyad S. Ahamed & Dr.Ali M. Mousa    year:2009

Abstract

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Copper powder and its alloys reinforced with SiCp ( 0- 10 wt%) were prepared using powder Metallurgy technique for a composite in which aluminum powder of ( 2 wt%) was added for improving wettability of the ceramic phase. . The mixture were blended with a ball mill for one hour to ensure a homogenous distribution on the composite .Green compacts pressed at (350MPa) using stainless steel die of (11) mm radius are then sintered at (900 °C) for two hours in an electric furnace, with argon atmosphere .Physical measurements like density, porosity, XRF, XRD, and Optical microscopy have been preformed . The microstructure of the composite presented a uniform distribution of SiCp in the matrix and good interfacial integrity. The density found to be decreased gradually with SiC content in three types (green, sintered and apparent density) especially from 4 wt% and above . Mechanical properties of the composites are investigated ,like Vicker’s hardness, compressive strength, and a dry sliding wear at constant speed ,under applied loads (5,10,15)N for two periods (10,20)min tests are then conducted for the sintered samples. The hardness , compressive strength of the composites has been increased with increasing SiC content, but at the cost of ductility. Wear performance will be enhanced with SiC content, compared with pure Cu alloys. This is due to the reinforcing SiC particles being effective to reduce the extent of wear deformation in the subsurface region during sliding. Finally electrical tests are prepared to measure electrical resistivity.It was found that more SiC content mean more electrical resistivity ,however it remains at fairly high level compared with the pure Cu alloys.

Deposition and Study Some Physical Properties of PbI2 Thick Films

By:Randa Kamel Hussain ALJubori   Supervised By:Assistant Proff.Dr. Ali M. M Alzuhery & Assistant Proff.Dr. Najat J. Saleh    year: 2006

Abstract

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In this work, simple and low cost method is adopted to prepare thick layers of lead iodide (PbI2); solution deposition method provides a chance to deposit large area with appropriate designed thickness, not needing complex techniques or assistance agents. Layers prepared by this method have the same properties of layers deposited in other methods. This work studies the influence of doping and annealing conditions (temperature and time) on the properties of lead iodide; three types of dopants were used with three different weights (0.0025, 0.005 and 0.0075gm), namely: AgNO3, CdSO4 and CaCl2. While annealing influence is studied in range (75-200 0C) for 1hour and 2 hours. The present study focused on the structural, electrical and optical properties of films prepared under different conditions. The experimental results of XRD showed polycrystalline hexagonal structure with four main peaks which correspond to (001), (101), (003), and (004) at d=6.807, 3.505, 2.304 and 1.713 respectively. It is found that the peak intensity changed with doping and annealing, and some shifts of peak positions accompanied the doping and annealing. The electrical measurements showed the electrical conductivity of PbI2 was (4.163x10-14 S.cm-1) and it increased when the film is illuminated by white light to (1.701x10-12 S.cm-1). The best ratio of photoconductivity to dark conductivity ( ) obtained from annealed undoped PbI2 at 200 0C for 2 hour (68.34). This ratio sharply decreased by doping, where the dark current is increased with increasing doping weight and with increasing annealing temperature; Ag and Cd dopants cause increment in dark conductivity ( ) 76.8 and 66.13 times when doped by (0.005gm) respectively. While adding the same amount of Ca caused dramatic decrease in dark conductivity with 6.7 times. Also the activation energies determined for different samples and their values changed within the range (0.0307 – 1.115 eV). According to linearity properties, it is found at voltage (> 350 V) and power (> 15x10-5 W) it is close to the superlinear behavior, while the behavior is more or less linear in the voltages (250-300V). For lower applied voltage (< 200 V) the behavior is sublinear. The linearity of PbI2 is enhanced by doping, where the photocurrent is superlinear at (> 250 V) and for incident power > 0.3 mW, that is clear in 0.0025gm of Ag, 0.005gm Cd and 0.0075 gm Ca doping case. The optical data were analyzed and interpreted in term of direct electronic transitions. Transmission spectrum of undoped lead iodide exhibit a sharp increment start around (~520 nm) and it becomes sharper with doping, and shifts occur by doping or by annealing. It was observed that lead iodide has wide direct band gap (2.36 eV), the energy gap is affected by doping and annealing; it decreased as the doping weight increased and as annealing temperature increased.

Study of Some Physical Properties of CdS Films Prepared by Chemical Bath Deposition

By:Selma Mohammed. H. Al-Jawad   Supervised By:Dr. Ali M. Mousa & Dr. Adawiya J. Haider    year:2006

Abstract

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In this work CdS films were prepared by using chemical bath deposition, which is a simple and inexpensive technique suitable for large deposition area. Many growth parameters have been considered in this work to specify the optimum condition, namely (temperature of solution, pH, thiourea ion concentration and deposition time). Structure, optical and electrical properties of CdS films are investigated and analyzed extensively with respect to growth conditions. Annealing in air at different temperatures (300, 350, 400, 450, and 500) at constant time of (30 min), also for different times (15, 30, 45, 60, and 90) min at constant temperature (300CO) is achieved. X-Ray analysis has confirmed the formation of cadmium oxide (CdO) with slight increase in grain size, shift towards lower scattering angle due to relaxation in the tensile strain for deposition films, and structure change from cubic and hexagonal to the hexagonal. From electrical properties, significant increase in electrical conductivity appeared in samples annealed at (300 ) for 60 min, and at (350 ) for 30 min. High quality films are achieved by adding chelating agent EDTA and buffer solution of to the deposition bath, leading to increase in transmission for films and increasing ratio of photo current to dark current. A high value of = using EDTA obtained, conforms the use of CdS as a photoconductive detector with high spectral responsivity of 0.257 A/W at 520 nm. Nanocrystalline CdS have been deposited, the band gap changes from 2.58 eV to 2.8 eV as compared to the bulk CdS band gap of 2.42 eV , as a result of quantum confinement. Nano crystalline CdS is deposited on the p- type silicon formation heterojunction, with high spectral responsivity of 0.41 A/W, quantum efficiency 90% , and specific detectivity 2.9 * cm . Also the shape of the spectrum of nano CdS/p-Si is extended into the blue region, due to widening of the window band gap. In addition, bulk CdS films deposited on p-type silicon, show increase in the spectral responsivity for the detector after annealing and also after adding chelating agent EDTA compared to the as- deposited films. High performance rectifying contact with a rectification ratio exceeding 20 is obtained by depositing nano crystalline CdS on p-type silicon. Annealing causes enhancement in the rectification ratio due to relaxation in the film structure.

Preparation and Investigation of Conductivity and Dielectric Behavior of Some Ferri-Ferro Composites

By: Inaam Mohammed Abdul Majeed Al-Obaidi   Supervised By:Dr. Khalid T. Mahdi & Dr. Sabah M. A.Ridha    year: 2005

Abstract

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Magnetoelectric composites are prepared in this work; these are containing ferrimagnetic and ferroelectric phases. The magnetoelectric effect couples two field effects. The first, magnetization due to application of electric field and the second, electric polarization due to the application of magnetic field. These materials are applied in the field of electronic technology. In this work, the ferroelectric phases BaTiO3 and SrTiO3 were prepared, while the ferrimagnetic-preparing phase was NiFe2O4, by using the conventional ceramic method. All formation phases were identified by X-ray diffraction pattern. In addition, particle size was measure for all the prepared phases. Dry pressing forming technique has been used to prepare three different ceramic compacts systems of (BaTiO3-NiFe2O4), (BaTiO3-Fe2O3), and (SrTiO3-Fe2O3) with different molar ratios. All compacts were fire at 1200 C˚ for 12 hrs, then all phases identified by using XRD. After grinding, polishing and etching, the microstructure of the samples were studied by using optical microscope. Results showed that, the increment in the bulk density with the content of BaTiO3 for (BaTiO3-NiFe2O4) system reaches at about 4.47 gm/cm3 with molar ratio of 75% BaTiO3 content. While for (BaTiO3-Fe2O3), the bulk density reaches about 4.88 gm/cm3 with molar ratio 75% Fe2O3, but for (SrTiO3-Fe2O3), the bulk density is 4.1 gm/cm3 with molar ratio 75% Fe2O3. Electrical investigations were carried out for all the prepared samples in the range of frequency of about (100 Hz-5MHz).The ac electrical conductivity increases while the dielectric constant and dielectric loss factor decrease as frequency applied electric field increases, then it reaches a constant value for all composites. It was observe the value of dielectric constant for the first system (BaTiO3-NiFe2O4) is (30-660). However, the dielectric constant in the range of (30-580) for the second system (BaTiO3-Fe2O3), while for the third system (SrTiO3-Fe2O3) in the range of about (40-730). The loss factor productions in the same range of frequency as mentioned above, for the first system acquire in the range (0.01-0.45). However, for the second system it was in the range (0.1-1.9). Finally, in the third system was in the range (0.01-1). The dc resistivity increases with increasing the temperature ranged between (300-500) K for all the samples. Finally, the variation in the thermoelectric power with temperature for the (BaTiO3-NiFe2O4) system decreases with increasing the temperature up to about 400 K˚ and remains constant for above that temperature, the majority of the charge carriers over the whole ranges of temperature are holes. However, for (BaTiO3-Fe2O3) and (SrTiO3-Fe2O3) systems, at lower temperature all the sample show positive seebeck coefficients and there is p-n transition observed in all composites at higher temperature.

Analytical Study for Ceramic – Metal Coatings Prepared By Plasma Spraying Technique

By:Ihsan Ali Abdul Kareem   Supervised By:Dr. Ala Alden Alnaimi & Dr. Khalid Taha Alrasoul    year:2005

Abstract

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The top coat 24MgO-ZrO2 and Al2O3 thermal barrier composite ceramic was sprayed using atmospheric plasma spraying technique on a NiCrAlY layer as the bond coat layer, deposited on a stainless steel 304 substrate. Fully stabilized zirconia base powder with three mixtures of 24MgO-ZrO2 and Al2O3 powders were used, with (80/20, 60/40, and 40/60) wt% (24MgO-ZrO2)/Al2O3 powder mixtures ratio. The visualization of the coating topography showed a variation and enhancement in porosity of the coating surface with the increased alumina ratio in the composite. The measured apparent porosity was 7.75% for the highest alumina content coatings. The adhesion strength of the coating was ~ 21.4 MPa. measured using test method (ASTM C633-01). The composite coatings also exhibited increasing in measured hardness values (3412-5387 MPa.) as a function of alumina content By subjecting the coatings to different heat treatment conditions (500-1000˚C) the thickness of the coatings decreased by (50, 16, 42 and 58%) for coatings produced from 24MgO-ZrO2, 80/20, 60/40, 40/60 wt% premixed ZrO2/Al2O3 powders respectively. The microstructure features were investigated via X-Ray diffraction. The analysis showed that the major coating phase was cubic zirconia with the minor magnesia phase; the alumina phase was identified as γ-alumina. The XRD pattern showed broadening diffraction lines with some shift in maximum peak position, due to small crystallite size and lattice micro-strain of zirconia. Various methods for size evaluations have been proposed for extraction of the size information in coating material. The crystallite size was calculated using four methods of crystallite size evaluation; Scherrer formula, FW1/5/4M, Integral Breadth and Fourier analysis methods. The convolution model was utilized with Gaussian, Lorentzian and Pearson7 functions. Due to overlapped diffraction lines, this study was confined to single line analysis with the focus being on the (111) reflection of cubic zirconia. The size analysis results showed that heat treatment promotes crystallite growth. The comparison showed that size results are dependent upon the character of diffraction peak shapes. One of the major objectives of this project is to study the thermal conductivity of the prepared coatings. Thermal conductivity measurements of the prepared coatings showed increasing values as the alumina ratio in the premixed powders increases, where the coatings produced from 20wt% alumina, showed an increase in the overall thermal conductivity of the composite coating by as much as a factor of two. Which are due to the anisotropic composite coating combined with the large difference in thermal conductivity between ZrO2 and Al2O3 will alter the thermal behavior of the coating.

اطاريح الدكتوراه لفرع الرياضيات وتطبيقات الحاسوب

Numerical Treatments of The Multi-dimensional Integral Equations

By:Rwayda Hazim Hassan   Supervised By:Asst. Prof. Dr. Ahlam J. Khaleel / Al-Nahrain University & Asst. Prof. Dr. Shatha A. Salman / University of Technology    year:2010

Abstract

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The main aim of this work is to give further studies for the multi-dimensional integral equations. This work includes the following aspects: Discuss the existence of the unique solution for special types of the multi-dimensional integral equations, namely the multi-dimensional Volterra non-linear integral equations of the second kind via Picard iterative procedure and Banach fixed point theorem. Devote the multi-dimensional differential transform for functions of multiple independent variables with some of its properties. Solve special types of the multi-dimensional Volterra non-linear integral equations of the second kind via the multi-dimensional differential transform method. Apply the homotopy perturbation method for solving special types of the multi-dimensional Volterra non-linear integral equations of the second kind.

Numerical Solutions On Integral-Algebraic Equations

By:Abdul Khaleq Owaid Mezaal AL-Jubory    Supervised By:Ass. Prof. Dr. Sahib K. JasimAss. & Prof. Dr. Ahlam J.Khaleel    year:2010

Abstract

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The main purpose of this work is to study integral and integro-differential equations that contain two different types of integral operators, these equations named as Volterra-Fredholm integral and integro-differential equations. This study includes the following aspects: (1) Discuss the existence and the uniquness theorem of solution of solution of the non-linear Volterra- Fredholm integral and integro-differential equations of the second kind via Banach fixed point theorem. (2) Gives some approximation methods for solving linear Volterra-Fredholm integral and integro-differential equations of the second kind, namely the expansion methods via Bernestain polynomials, Neumann series and the power series method. (3) Uses the power series method to solve special types of non-linear Volterra-Fredholm integral and integro-differential equations of the second kind.

Mathematical Modeling and Analysis Technique of Stream Cipher Cryptosystems

By:Ayad Ghazi Naser Al-Shammari   Supervised By: Professor Dr. Abdul Monem S. Rahma & Asst.Professor Dr. Shatha A. Salman    year:2009

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The Periodicity, Linear Complexity, Randomness and Correlation Immunity used as basic criterions to measure Key Generator Efficiency. The key generator depends basically on LFSR which is considered as one of the basic units, beside the combining function, of stream cipher systems. Through this thesis, these basic criterions can be calculated theoretically for any key generator before it be implemented or constructed (software or hardware). The implementation of the basic efficiency criterions on keygenerator reduces the time and the cost since the implementation of these tests applied before the final practical construction of the keygenerator. To approach efficient keygenerator, some conditions, which must be available in any keygenerator, are introduced. The Linear, Product and Brüer cryptosystems are chosen to be our study cases. This work introduces the mathematical proof of the good efficiency of the Linear and Brüer keygenerator deterministically. In the same time, we introduce the fail of the Product keygenerator to pass the basic efficiency criterions tests. Lastly this thesis introduce the theoretical and practical evolution of the three study cases and the evolution results appear that Brüer keygenerator is the best among the other keygenerator.

Solvability of Non-Linear Unbounded Optimal Control Operator Equations in Hilbert Space Via One Parameter Semigroup Approach

By:Samir Kasim Hassan   Supervised By:Asst.Prof.Dr.Radhi Ali Zboon / Al-Mustansiriyah University & Asst.Prof.Dr.Jehad Ramadhan Kider / University of Technology    year:2009

Abstract

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The main aim of this thesis is to study and develop some mathematical properties of some classes of non-linear dynamical control problems in infinite dimensional space with bounded perturbation and unbounded linear control operator using the concept of one-parameter family of strongly continuous semigroups generated by some unbounded linear generators. The necessary background for this approach has also been presented and supported by some useful concluding remarks. The mild principles, spectral conditions for stability and unstability have also been discussed and developed for certain class of non-linear dynamical control system in the presence of input in some infinite dimensional space, by using the principle of composite perturbation strongly continuous semigroup generated by some infinitesimal unbounded generator. Finally, -optimal control problem in infinite dimensional spaces are also presented. Some optimal control problems and solvability, controllability, null controllability, perturbed Recatti operator equation as well as some of its properties are discussed and developed via evolution perturbed strongly continuous semigroup generated by the linear unbounded perturbed generators.

Lie Algebras and Stability of Switched Linear-Nonlinear Systems

By:Kuther Abood Nemaa    Supervised By: Asst.Prof.Dr.Fadhel Subhi Fadhel / Al-Nahrain University & Asst.Prof.Dr.Jehad Ramadhan Kider / University of Technology    year: 2009

Abstract

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The main objective of this thesis is to study the stability of switched non-linear systems and to find the conditions for stability under arbitrary switching. Also, this work consist of analyzing stability for switched systems which are composed of both continuous and discrete time subsystems by considering a Lie algebra generated by all subsystems of matrices, we showed that if all subsystems are Hurwitz-Schure stable and this Lie algebra is solvable, then there is a common quadratic Lyapunov function for all subsystems and thus the switched system is exponentially stable under arbitrary switching. If some subsystems are unstable while the same Lie algebra is solvable, then we had prove that there is a common quadratic Lyapunov-like function for all subsystems and the switched system is exponentially stable under a dwell time scheme.

About the Generalized Spline Functions and its Generalization for Two-Dimensional Spaces

By:Nabaa Najdi Hasan   Supervised By: Dr. Fadhel Subhi Fadhel & Dr. Suha N. Al-Rawi    year: 2009

Abstract

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The first objective of this thesis, is oriented towards function approximation using special type of spline functions, which is called the generalized spline functions including its basic theory. General formula for each type of generalized spline is derived. The second objective of this work is the generalization of generalized spline functions for two-dimensional spaces by tensor product methods. The properties of tensor product are used in this generalization to get the two dimensional approximation function. Finally, applications of the generalized spline functions method in solving ODE and PDE problems are given.

Complete Arcs and Surfaces in Three Dimensional Projective Space Over Galois Field

By:Amal Shihab Al-Mukhtar   Supervised By:Prof.Dr.Mohammed Serdar I.Kirdar    year: 2008

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The purpose of this thesis is to construct surfaces and complete arcs in the projective 3 – space PG(3,q) over Galois fields GF(q), q = 2, 3 and 5. A(k,n) – arc in PG(3,q) is a set of k points, no n + 1 of them are coplanar. A(k,n) – arc is complete if it is not contained in a (k + 1,n) – arc. In this work the (k,r) – caps and (k, ) – spans are constructed in PG(3,2) and PG(3,3) and it is found that the maximum (k,2) – cap, which is called an ovaloid, exists in PG(3,2) when k = 5 and also exists in PG(3,3) when k = 8. Moreover, the maximum (k, ) – span, which is called a spread, is found to exist in PG(3,2) when k = 5 and exists in PG(3,3) when k = 10.

On Approximated Solutions of Partial Integro –Differential Equations of Fractional Order

By:Sajeda Kareem Radhi   Supervised By:Ass.Prof.Dr.Omar M.Faour    year: 2007

Abstract

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الاهتمام الاساسي في هذه الاطروحة ينصب على تأسيس خلفية نظرية لتعريف ريمان-ليوفيل Riemann-Liouville) ) للاشتقاق والتكامل الكسري لدالة لمتغيرين وكذلك حل نوع معين من معادلات فريدهولم(Freadholm) الخطية الجزئية التكاملية التفاضلية ومعادلات فريد هولم الخطية الجزئية التكاملية التفاضلية ذات الرتب الكسرية بأستخدام بعض الطرق التقريبية، حيث تم أستخدام نظرية النقطة الثابتة (Banach Fixed Point Theorem) لبرهان وجود ووحدانية الحل لهذه النوعية من المعادلات. تم استخدام طريقتين من طرق البواقي الموزون (Weighted Residual Method) وهما طريقة التجميع(Collocation) وطريقة كاليركين(Galerkin) لمعالجة هذه المعادلات بصورة تقريبية وايضا" تم استحداث طريقة الفروق المنتهية الصريحة وتم استخدامها لتقريب الحل لكلتا المعادلتين(PIDE) و(FPIDE) . أضافة الى ذلك فقد تم مناقشة تقارب واستقرارية الطرق التقريبية الثلاث. وفي النهاية تم كتابة برنامج لكل واحدة من الطرق بأستخدام Matlab(v.7) .

ON HIGHER DERIVATIONS AND HIGHER HOMOMORPHISMS OF PRIME RINGS

By:Anwar k. Faraj    Supervised By:    year: 2006

Abstract

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Let R be a ring not necessarily with an identity element. A wellknown result proved by I.N.Herstein concering derivations in prime rings have been extensively studied by many authors like, M.Bresar, N.M.Shammu and M.Ashraf and N.Rehman. Also, C. Haetinger and M.Ferro extended this result to higher derivations. The main purpose of this work is i. Extend N.M.Shamm's theorem to higher N-derivations by giving the concept of higher N-derivation. A higher Nderivation of a ring R is defined as a family of additive mappings of R into itself such that d (ur su) d (u)d (r) d (s)d (u) i j i j n n + = ∑ i j + + = , for all u ∈U , r,s∈R , n ∈ N,where U is a Jordan ideal of R. ii. We answer the question of C.Haetinger and W.Cortes whether the result of C.Haetinger and M.Ferro is also true for Jordan generalized triple higher derivations. iii. We introduce the concept of (U,R) derivations and generalized (U,R) derivations. Then we extend Awatar's theorem and we extend this result to higher (U,R) derivations and generalized higher (U,R) derivations by giving corresponding definitions. A well-known result of I.N.Herstein concerning Jordan homomorphism and Jordan triple homomorphism has been extensively extended by M. Bresar. Also R.C. Shaheen extended these results to generalized Jordan homomorphism and generalized Jordan triple homomorphism iv. We introduce the concepts of higher homomorphism, Jordan homomorphism and generalized Jordan triple homomorphism and their generalization and we extend the above results and study these concepts onto 2-torsion free prime ring.

Approximate Solutions for Singular Integral Equation with Cauchy Kernel

By: Abdulbaset Muhsen Aial   Supervised By: Dr. Mohamed S. Ismail & Dr. Omar M. Al-Faour   year:2006

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The aim behind this thesis is to find out the approximate solutions of the singular integral equation with Cauchy kernel. These equations embrace singular points. To do away with these singular points, special types of approximation must be found owing to the fact that direct methods cannot be applied. The approximate solutions for these equations have been arrived at by the use of the following methods:- Collocation method: In this method the solution is represented as a power series with unknown coefficients multiplied by a weighted function and then Chebyshev zeros are used as collocation points to find unknown coefficients. Gaussian-quadrature method: In this method a new approximation technique has been used in which the required unknown function is represented as a result of multiplying two orthogonal functions including (Chebysheve polynomials of first and second kinds and Jacobi polynomials). The properties of this function have been employed to eliminate the effect of the singular points. Trigonometric polynomials method: by the use of the same methods, a special type of approximation, then trigonometric functions and orthogonality properties, to find a system of linear algebraic equations which can be solved numerically. All these employed methods have yielded reliable and stable results even in the case of using a large-scale node. Algorithms and programs have been written in Fortran language for all the above-mentioned methods.

ON PRIMARY SUBMODULES

By:Lemeas J. Mohammed   Supervised By: Dr. Adil G.Naoum    year: 2005

Abstract

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Let R be a commutative ring with identity and let M be a unitary left R-module. A proper submodule N of M is said to be Prime if re ∈ N for r ∈ R, e ∈ M implies that either e ∈ N or r ∈ [N : M]. prime submodules have been studied extensively by many authors, like S.A.Saymeh, C.P.Lu, R.L.McCasland, M.E.Moore, P.F.Smith, K.Divaani-Aazar and M.A.Esmkhani. primary submodules are generalizations of prime submodules. The main goal of this thesis is to look for generalizations of results on prime submodules to primary submodules. A proper submodule N of an R-module M is said to be Primary if re ∈ N for r ∈ R and e ∈ M implies that either e ∈ N or r ∈ p [N : M]. One of our goals of this work is to give some useful properties and characterizations of primary submodules. Furthermore we generalize the concept of the prime radical of a submodule to the primary radical. The primary radical of a submodule N , pradM(N ) is defined as the intersection of all primary submodules of M which contain N , and if no such submodule exists, we put pradM(N ) = M. And we give a characterization of the primary radical of a submodule N as: pradM(N ) = \ K(N ,P n )| P is a prime ideal of R, n ∈ Z + . Then we describe the elements of pradM(N ) for a finitely generated submodule of a free module. One of our important results is the Primary Avoidance Theorem, as a generalization of the Prime Avoidance Theorem. We introduce the concepts of p-compactly packed , strongly p-compactly packed, coprimarily packed and strongly coprimarily packed submodule. We investigate their vii properties, and discuss the relations between them. Finally, we give the definitions of associated and supported primary ideals of a module M and a characterization for each of them and study some of their fundamental properties. Also we define the associated and supported primary submodules of M and give some results about them.

حول الحلول التقريبية لمنظومة معادلات فولتيرا التكاملية اللاخطية

By:برهان فخرالدين جمعة   Supervised By: د. عمر محمد عبد المجيد الفاعور   year: 2005

Abstract

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الهدف الرئيسي لهذه الاطروحة هو دراسة وتطوير بعض الطرق التحليلية والتقريبية مع عرض بعض الخوارزميات الجديدة لمعالجة منظومة معادلات فولتيرا التكاملية اللاخطية من النوع الثاني. بالنسبة للمعالجات التحليلية تم تطوير احدى الطرق لحل معادلة فولتيرا اللاخطية وهي طريقة التقريبات المتتالية والتي تسمى أيضا (طريقة بيكرد) والتي أستخدمت لحل منظومة أعلاه. كذلك تم تعميم نظريات الوجود والوحدانية الخاصة بالمعادلة تكاملية اللاخطية الى منظومة معادلات تكاملية اللاخطية. أضافة الى ذلك , تم أستخدام ثلاث أنواع مختلفة من دوال الثلمة (التقليدية, التوصيلية وكاتمول-رام) لحل المنظومة أعلاه عدديا. ثلاث أنواع مختلفة من دوال الثلمة التقليدية(الخطية, التربيعية, التكعيبية) طورت وطبقت لاول مرة لمعالجة المنظومة أعلاه. خمس رتب مختلفة من دوال الثلمة التوصيلية (الأول, الثاني, الثالث, الرابع, الخامس) طورت وطبقت لاول مرة لمعالجة المنظومة أعلاه. نوعيين مختلفين لنوع جديد من دوال الثلمة وهي كاتمول-رام (ألاول و الثاني) طورت وطبقت لاول مرة لمعالجة المنظومة أعلاه. الصيغة العامة لمشتقة الصيغة الجديدة لدوال الثلمة التوصيلية أشتقت وطبقت لمعالجة المنظومة أعلاه عدديا. تم مناقشة أستقرارية وأقتراب ألانواع المختلفة لدوال الثلمة. أخيرا, تم كتابة الخوارزميات والبرمجيات بلغة (MATLAB\R14 ) لكل من الطرق الأنفة الذكر.

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