Munirah Abdullah Almessiere

Microstructural and Thermal Properties of Porous Aluminum Filled with Nanocrystalline Silicon

In this work, the structural, thermal and optical properties of porous aluminum thin film carried out with various intensities of the anodization current in sulfuric acid. The obtained pores at the surface are filled by nanocrystalline silicon (nc-Si) thin films deposited by plasma enhancement chemical vapor deposition (PECVD), which the role is to improving its optical absorption and thermal properties. The prepared sample is an assembly of three different media such as Al sample/ Porous aluminum layer filled with silicon (PAS)/ nanocrystallite silicon layer (nc-Si). The effect of anodization current on the microstructure of porous aluminium and the effect of the deposited silicon layer were systematically studied by atomic force microscopy (AFM), X-ray diffraction (XRD) and Raman spectroscopy. The thermal properties such as the thermal conductivity (K) and thermal diffusivity (D) were determined by the photo-thermal deflection (PTD) technique, which is a non-destructive technique. Based on this full characterization, it is demonstrated that the thermal and optical characteristics of this films are directly correlated to their microstructural properties.

Excess conductivity analysis in YBa2Cu3O7−d added with SiO2 nanoparticles and nanowires: Comparative study

The effect of nanosized silicon oxide nanoparticles (denoted NP-SiO2) and nanowires (denoted NW-SiO2) additions during the final processing stage on electrical fluctuation conductivity of polycrystalline YBa2Cu3Oy (Y-123 for brevity) in the mean field region has been reported. Series of samples were synthesized in air using a standard solid-state reaction technique by adding nanosized entities up to 0.5 wt.%. Phases, microstructure and superconductivity properties have been systematically investigated using X-ray diffraction (XRD), transmission electron microscopy (TEM) and electrical measurements. TEM investigations show the presence of inhomogeneities embedded in the superconducting matrix along with the presence of columnar defects in the case of SiO2 nanoparticles added samples, however nanowires tend to agglomerate by entangling with each other in the intergrain regions. The fluctuation conductivity was analyzed as a function of reduced temperature using the Aslamazov–Larkin model. Using the Lawrence–Doniach equations, the Ginzburg–Landau (GL) number (NG) and equations, the coherence length, the effective layer thickness, the lower critical field Bc1(0), the upper critical field Bc2(0) and the critical current density Jc(0) were estimated. It was found that the addition of an optimum concentration of SiO2 nanomaterials, that depends on the shape, effectively controlled the microstructure, the grains coupling and hence improved the physical properties of Y-123 compound.

High Thermoelectric Figure of Merit of Ag 8 SnS 6 Component Prepared by Electrodeposition Technique

A new thermoelectric material Ag8SnS6, with ultra-low thermal conductivity in thin film shape, is prepared on indium tin oxide coated glass (ITO) substrates using a chemical process via the electrodeposition technique. The structural, thermal and electrical properties are studied and presented in detail, which demonstrate that the material is of semiconductor type, orthorhombic structure, with a band gap in the order of 1.56 eV and a free carrier concentration of 1.46 × 1017 cm−3. The thermal conductivity, thermal diffusivity, thermal conduction mode, Seebeck coefficient and electrical conductivity are determined using the photo-thermal deflection technique combined with the Boltzmann transport theory and Cahills model, showing that the Ag8SnS6 material has a low thermal conductivity of 3.8 Wm−1K−1, high electrical conductivity of 2.4 × 105 Sm−1, Seebeck coefficient of − 180 μVK−1 and a power factor of 6.9 mWK−2m−1, implying that it is more efficient than those obtained in recently experimental investigations for thermoelectric devices.

Au, Ag, and Tio2 green synthesis and applications as antibacterial for both Gram positive and Gram negative strains

Method & Materials: Total 8 rabbits (male, older than 16 weeks) were divided into two groups of early cranioplasty group (EG, 4 rabbits) and delayed cranioplasty group (DG, 4 rabbits). The rabbits of each group were performed cranioplasty via frozen autologous bone flaps 4 weeks (EG) and 8 weeks (DG) after craniectomy. In order to obtain control data, the cranioplasty immediate after craniectomy were made on the contralateral cranial bone of the rabbits (control group, CG). The bone fusion and new bone formation were evaluated by micro-CT scan and histological examination 8 weeks after cranioplasty on both groups was done.S processed thin-film photovoltaic (PV) solar technologies, such as polymer and perovskite solar cells (PSCs), may provide low-cost electricity generation. These technologies suffer from insufficient light absorption due to thin absorbers. Metallic nanoparticles (NPs) exhibit a localized surface plasmon resonance (LSPR) and act as scattering centers and subwavelength antennas, so metallic NPs can be incorporated into thin-film solar cells to effectively improve the light absorption of light harvesting devices. We have embedded various metallic nanocomposites into the electron transport layer (ETL) or the hole transport layer (HTL) of polymer and perovskite solar cells to investigate the photovoltaic effects of the PV cells with metallic nanostructures. The PSC device achieved a significant enhancement of the UV stability and 34.2% improvement of the power conversion efficiency (PCE) by combinational use of Au NPs and insulating MgO in mesoporous TiO2. The polymer PV device demonstrated improved stability and 14.5% improvement of PCE by embedding AgAl nanostructures into the HTL. Solar cell performance observations and results indicate that the LSPR and electrical effects of metallic nanostructures enhance the photovoltaic response of both kinds of PV cells, by causing an incredible improvement in the photocurrent density as a dominant factor. The fundamental optics and physics behind the plasmonic polymer and perovskite solar cell was studiedI this study LTA, zeolite was prepared from Saudi white silica as a main source of silica. The effect of ultrasonic irradiation on the crystal structure and ability to ion exchange of some heavy metals were studied. Many techniques were used to characterize the prepared zeolite includes XRD with crystal lattice analysis, EPR and finally ion exchange isotherm of some heavy metal ions. The results showed that the ultra-sonicated zeolite exhibits different behavior towards ion exchange with increasing its capacity. The ultra-sonicated zeolite showed little increase in the lattice parameters with increasing in the crystal size. Fitting adsorption isotherms on the metal adsorbed showed an observable change in the behavior of ultra-sonicated zeolite towards the metals exchanged.T binding of the receptor activator of nuclear factor kappa-B ligand (RANKL) to the receptor activator of nuclear factor kappa-B (RANK) on pre-osteoclast is essential for osteoclast maturation and activity. Osteoproteogerin (OPG) is a soluble decoy receptor for RANKL. Its binding to RANK prevents binding of RANKL to RANK and subsequent hinders activation of osteoclast. Various in vivo studies and clinical trials have investigated the systemic use of OPG in treatment of bone diseases. Chitosan is a cationic polymer derived from chitin. This material has antimicrobial activity, biodegradability, and mucoadhesive properties, making it an ideal material for biomedical applications. It also promotes cell adhesion, proliferation and differentiation. It is suggested that the local application of new formulated OPG-chitosan preparation may have similar osteogenic potential in the bone defect. The objectives of this study are: (i) to formulate of different forms of OPG-chitosan gels from different molecular weights of water-soluble chitosan (10, 25, 50 kDa), (ii) to evaluate the gels biodegradation, (iii) to determine amount of OPG protein release from gels and (iv) to evaluate the cytotoxicity of gels by Alamar Blue assay and scanning electron microscope. (iv) Efficacy of gel on bone regeneration in rabbit. From our studies we conclude that our gels are (i) non-toxic (ii) biodegradable and (iii) exhibits sustained release property. (iv) OPG-chitosan has a positive effect on bone formation. Therefore, we have proven that OPG-chitosan gel is evidently viable to be used locally for potential bone defect application.This Article is Available in: https://www.imedpub.com/archives-in-chemistry/ Polymer nano-composites have received immense attention in the recent years, as many of these materials present promising properties like high flexural strength, improved pressure barrier properties and depleting flammability. Polycarbonate is one of the most interesting ones, due to characteristic properties like high toughness and strength, excellent ballistic strength and good visual clarity. It could be expected that the addition of relatively low percentages of nano-reinforcements will result into remarkable improvements in mechanical and thermal properties. In this work, (Cloisite 25A) nano clay, Araldite LY 556 epoxy, HY 951 hardener were used to prepare the matrix at various blends 0%, 4%, 8%, and 10% by using hand layup method. And further detailed analysis was performed to study the tribological property of various percentage nano-clay (Cloisite 25A) loaded epoxies, with inclusion of jute fiber using Taguchi’s technique. For this purpose, the test samples were prepared according to the ASTM: G99 standard, and the test was carried out with the assistance of Pin-onDisc machine. For this experimentation L16 orthogonal array was used to evaluate the tribological property with four control variables such as % of nano-clay content, normal load, sliding velocity and sliding distance at each level on friction co-efficient along with wear rate. From the obtained results the combination of factors greatly influenced the process to achieve the minimum wear and coefficient of friction for jute fiber reinforced laminates were analyzed. The microstructure behavior of the fabricated samples were investigated with assistance of Scanning Electron Microscope (SEM), particle distribution was analyzed throughout the matrix by Transmission Electron Microscopy (TEM) analysis before and after the wear test. ANOVA analysis revealed the nano clay contribution on coefficient of friction and wear of the jute fiber laminate composites.I the present study, isotactic polypropylene (PP)/local organoclay (OC) nanocomposites were prepared by two different methods, namely extrusion and casting method. Cationic surfactant, Hexadecylpyridiniumchloride(CPC) is used to modify the Khulays clay from Saudi Arabia after saturating its surface with Na+ ions. The crystalline structure and properties of OC and PP /OC were investigated by FTIR, XRD, DSC, TEM, SEM to establish the correlation between the preparation method and the degree of clay intercalation/exfoliation in PP matrix. Using simple combustion apparatus, the effect of organoclay content on the flammability behavior of the PP/organoclay was investigated by horizontal burning tests for HB classification, Underwriters Laboratories (UL94). The above investigations reveal that PP/OC nanocomposites prepared by extrusion have the most extensive dispersion of OC particles and high levels of exfoliation compared to that prepared by casting method. The vertical burning tests results showed increase in the ignition time and significant reduction of flame propagation rate of PP/ organoclay nanocomposites compared to neat PPD the emergency of competing materials carbon nanotubes remain at the fore-front of the promising materials for organic electronics like field-effect transistors. Due to their properties, are among the most suitable structure to support the current advancements goals in flexible electronics. However, very few are the ways to make stable single walled carbon nanotubes (SWNT) dispersions for simple processing. To further push the adoption of this kind of devices in everyday life applications, high-throughput dispersion and fabrication methods must be adopted. In this work, we highlight how a simple process for chirality selection and dispersion of semiconducting SWNT may be used for the realization of all-printed Field Effect Transistors. Chirality selection is operated by polymer-wrapping of the s-SWNTs with poly [(9, 9-dioctylfluorenyl-2,7diyl)-alt-co-(6,6’-{2,2’-bipyridine})] in common organic solvents, with a process optimized for the [6,5] chirality selection. After solution purification, wrapped nanotubes can be dispersed in those solvents suitable for printing. The printing process was performed in ambient air and at room temperature, and the SWNT ink was dispense using a nozzle with an orifice diameter of 60μm over pre-patterned source and drain electrodes. The devices exhibit ambipolarity, with a slight prevalence of the n-type behavior. For both electron and hole accumulations, at VDS = ± 5V (linear regime) 10 6 on-off ratios can be observed, with mobilities (μlin) around 0,3 cm2V -1s-1 for both carrier types. In saturation regime (VDS = ± 60 V) mobility values (μsat) up to 0.8 cm2V-1s-1 for electrons and 0.65 cm2V-1s-1 for holes are reached. The study also highlights the effects of different solvents on the carbon nanotube network formation and transistor performances with best results with those solvents that tend to form polymer pre-aggregates in the printed solution.A groundwater, used as drinking water, has been creating several problems in different countries around the World. The present existing reports of diverse countries showed arsenic concentrations in drinking water is much higher than those proposed by the World Health Organization (10 μg/L). Nanomaterials and nanotechnologies inspire new possible solutions to major environmental issues nowadays. It has been reported that adsorption strategies using nanoparticles turned beneficial as hematite proved to be very efficient for the removal of arsenic in drinking water. However, the adsorption mechanism is not yet clear. In order to shed light on this subject, we attempt to study the interactions between arsenic species and α-Fe2O3 nanoparticles in aqueous medium. The iron oxide nanoparticles were prepared using a solvothermal method. Synthesized hematite nanoparticles were put in contact with As2O3 solutions at room temperature and at pH 4 and 7. The nanoparticles were characterized by FTIR, XRD, UV-vis, XRF and XPS. The results showed that synthesized nanoparticles had an average diameter of crystallite of 30 nm and from XRD pattern also was confirmed a rhombohedra hexagonal closepacked phase for the powders obtained (α-Fe2O3). From optical studies was evidenced that hematite nanoparticle obtained, have semiconductor properties due to band gap value, in this case 2.2 eV. The presence of arsenic on particles surface was confirmed, which is more remarkable when pH=7 condition is employed. On the other hand, after adsorption experiment, it was evident from FTIR and XPS that once arsenic species interact with the nanoparticles, they form mono and bi-dentate surface complexes. The developed methodology could be implemented in the water treatment industries, reducing the costs of the processes and making them more environmental friendly.N natural fibers form an interesting alternative for the most widely applied fiber in the composite technology. Natural biodegradable polymers are called biopolymers. There are two main renewable sources of biopolymers, i.e. (i) starch, polysaccharides and cellulose and (ii) proteins. To improve the mechanical properties of such polymers or to enrich their degradation rate, natural polymers are modified using chemicals. The use of hemp fibers as reinforcement in composite materials has increased in recent years as a response to the increasing demand for developing biodegradable, sustainable, and recyclable materials. Hemp fibers are found in the stem of the plant which makes them strong and stiff, a primary requirement for the reinforcement of composite materials. In the present work, Hemp composites are developed under chemical treatment (Alkaline, Acrylonitrile and Benzoylation treatments) and their mechanical properties are evaluated. Mechanical properties of Hemp/polymer are compared with glass fiber/epoxy. These results indicate that Hemp can be used as a possible reinforcing material for creating low load bearing thermoplastic composites.A series of semi-interpenetrating polymer network (semi-IPN) hydrogel based on poly (vinyl alcohol) (PVA) and poly (N-isopropylacrylamide) (PNIPAAm) were prepared by emulsion polymerization. There were 5 samples composed of different amount of initiators and catalysts for emulsion polymerization. The changes of particle sizes of each hydrogel were monitored at temperatures 30oC, 35oC 40oC and 45oC respectively. The optimal hydrogel was coated onto cotton fabrics and then the coated fabrics were investigated by swelling experiment, scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy. The thermo-behavior of the semi-IPN hydrogel is observed. Experimental data indicates the amount of initiators and catalysts added is an influential factor for the formation of optimal hydrogels while the concentration of hydrogel is not. The coated fabric is able to change the swelling ratio by 10.1% at the Lower Critical Solution Temperature (~35oC), which means the fabric is sensitive to the change of temperature. SEM results indicate that the semi-IPN hydrogel affects the surface appearance of the cotton fabric. Further confirmation of chemical structure is completed by FTIR spectroscopy.

Using Deionized Water with Ethanol as a Solvent of CuS EGFET as pH Sensor

In this research work, copper sulphide was deposited on glass substrate using spray pyrolysis deposition. The precursors were dissolved in deionized water (DIW) and ethanol, mixed at a ratio of 7:3. The distance between nozzle and substrate was 30 cm and the substrate temperature was maintained at 200 °C. XRD spectra analysis showed four distinctive peaks of high intensity, which indicate pure CuS covellite phase with average crystallite size of 28.3 nm. FESEM characterization of the thin film structure showed a mixture of very small nanoplates and larger square-and triangular-shaped particles. The application of the film as pH sensor showed it has exceptional qualities that include sensitivity and linearity of 22.9 mV/pH and 93.8%, hysteresis of 23.75 mV, repeatability (C.V.) of 0.11% for pH7, stability and reliability (C.V.) of 0.13%, 0.12% and 0.08% for pH 4, 7 and 10, respectively. This research work confirms the feasibility of using CuS thin film as extended membrane in pH sensor and biosensor applications.

Fabrication, characterization of ZnO nanorods on the flexible substrate (Kapton tape) via chemical bath deposition for UV photodetector applications

One dimensional ZnO nanorods have been synthesized on flexible substrate. The substrate is Kapton Tape (KT). ZnO Nanorods are produced by using low cost chemical bath deposition method at low temperature. The investigation of the effect of substrate on the morphological, elementary composition, structural characteristics and Raman spectroscopy of ZnO nanorods has been done. Field emission scanning electron microscopy (FESEM), Energy Dispersive analysis (EDX), X-ray diffraction (XRD) and Raman spectroscopy measurements are employed to examine the morphological, compositional and structural characteristics with hexagonal wurtzite structure of the ZnO nanorods arrays. The results found that the average diameter of ZnO nanorods is found to be closely related to the substrate nature. It is concluded that the substrate can effect on the ZnO nanorods growth remarkably and the selective growth of ZnO nanorods is possible through the choice of the substrate. The crystallite size and the lattice constants of the sy...