Structural and Optical Properties of Tin Doped Zinc Oxide Fibres Prepared By Electrospinning Technique

The study synthesized ZnO fibers using electrospinning technique. It also characterized and determined the effects of Sn2+ dopant on the optical properties of the fibers synthesized. This was with a view to exploring the potential of improving the performance ZnO semiconductor material in industrial applications. Polyvinyl Alcohol (PVA) solution was prepared and mixed with ZnO source. Zinc acetate was used as the ZnO source while Tin Acetate was used as Sn2+ dopant source. Viscous electrospinning solutions of PVA/Zinc Acetate and three different compositions of Tin Acetate were prepared. The compositions of dopants used were 5, 7 and 9-wt. %. Samples of the depositions from the electrospinning process were annealed at 600o C at a rate of 4o C per minute for 6 hours. Scanning electron microscopy (SEM) was employed to reveal the morphology of the depositions. The structural analysis of the fibers was carried out using x-ray diffractometry (XRD) while the optical properties of the fibers were investigated using ultra violet visible spectrophotometry. The SEM results showed the depositions to be web of fibers. The XRD confirmed the crystallization of undoped and doped ZnO fibers from the acetates. The crystal sizes of the fibers were in the range of 5.566 to 7.202 nm. Furthermore, wide bandgap energy values ranging from 3.26 to 3.46 eV were obtained from the results of the optical properties of the fibers. The results showed that the average crystal sizes of Sn2+ doped ZnO fibers were larger than those of the undoped fibers. However, it was observed that the average crystal size decreases with increase in Sn2+ content. The results also showed that the bandgap energy values of the fibers increase with dopant concentration. The study established the viability of fabricating doped and undoped ZnO structure in form of fibers in order to enhance its performance in industrial applications. Also, the results showed that the optical properties of the fibers improved with increase in Sn2+ dopant concentration. Keywords: ZnO fibers; Electrospinning technique; Structural analysis; Optical properties;  Sn2+ Dopant; Band gap energy value; Crystal siz

Electro-chemical deposition of zinc oxide nanostructures by using two electrodes

One of the most viable ways to grow nanostructures is electro deposition. However, most electrodeposited samples are obtained by three-electrode electrochemical cell. We successfully use a much simpler two-electrode cell to grow different ZnO nanostructures from common chemical reagents. Concentration, pH of the electrolytes and growth parameters like potentials at the electrodes, are tailored to allow fast growth without complexity. Morphology and surface roughness are investigated by Scanning Electron and Air Force Microscopy (SEM and AFM) respectively, crystal structure by X-Ray Diffraction measurements (XRD) and ZnO stoichiometry by core level photoemission spectroscopy (XPS)

Optical Nanoantennas for Multiband Surface-Enhanced Infrared and Raman Spectroscopy

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Accountability issues in basic schools of Ilorin Metropolis, Kwara State, Nigeria

Concern for improvement in the quality of education in Nigeria, as in other countries, in recent years has raised demands for accountability from schools and particularly teachers. Using the descriptive survey design, this study examined the level of accountability among basic education teachers, strategies for promoting accountability at the basic education level and likely challenges against holding teachers responsible for their students’ learning. Twenty five officials in charge of basic education in Kwara State Ministry of Education (MOE) and State Universal Basic Education Board (SUBEB) and 30 teachers each at the primary and junior secondary schools in Ilorin Metropolis were selected as the study participants, using stratified random sampling technique. Evaluation and Accountability Questionnaire (EAQ) with reliability coefficient of .78 was used for data collection. Descriptive statistics of percentage, mean and rank-ordering were used to answer the five research questions raised in the study, while chi-square was used to test for significant difference on issues relating to accountability between educational administrators and teachers, at .05 level of significance. Findings revealed that teachers felt moderately responsible for their students’ academic performance, especially in Mathematics. Thorough supervision and use of rewards were the best measures of promoting accountability while lack of sufficient instructional aids was seen as the greatest obstacle to teachers’ accountability. It was recommended that: effective accountability policies be formulated for basic education in Nigeria with explicit rewards and sanctions; meaningful support needs to be provided for the schools, educators and students; and supervision should be all-encompassing, focused on teaching, examinations and overall students’ needs.tasty’s vide

Rutherford Backscattering Spectrometry Analysis and Structural Properties of ZnxPb1-xS Thin Films Deposited by Chemical Spray Pyrolysis

Zinc lead sulphide ternary thin films were prepared by chemical spray pyrolysis on soda lime glass substrates using zinc acetate, lead acetate, and thiourea sources precursor. The films were characterized using Rutherford backscattering (RBS) spectrometry, energy dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM), and X-ray diffractometry (XRD). RBS studies revealed variation in thickness and stoichiometry of the films with respect to compositional substitution between Zn and Pb, thereby giving effective composition ZnxPb1-xS, where x=0, 0.035, 0.069, 0.109, 0.176, and 0.217. Film thickness obtained by length conversion ranged from 81.02 nm to 90.03 nm. Microstructural analyses also indicated that the growth and particle distribution of the films were uniform across substrate’s surface. Diffraction studies showed that the films possess FCC crystalline structure. Crystallite size reduced from 14.28 to 9.8 nm with increase in Zn2+ in the ZnxPb1-xS samples

Computer-based tests: a system of assessing academic performance in university of Ilorin, Ilorin, Nigeria

This paper examined the nature, structure, and scope of computer based test (CBT). Specifically, it dealt with the use of CBT for conducting General Studies’ papers usually coded as GNS with particular focus on the University of Ilorin. The mode of use, scope, coverage and the nature of assessment were discussed. In addition, the organization of the course contents in relation to the needs of the learner were explained, however only GNS 311 was sampled being the highest point of the evolutionary trend of the course structure. Finally, the problems associated with the conduct of CBT and recommendations for ease of administration and future use were highlighted

Spray Pyrolysis Deposition and Characterisation of Dielectric SnO2 Thin Films

Dielectric and optical dispersion properties of thin films of SnO2 deposited via spray pyrolysis were investigated. These properties are fundamental to new applications of SnO2 in energy storage and pressure sensing. The composition and thickness of the films were determined using the Rutherford Backscattered Spectroscopic mode of the Pelletron Tandem Accelerator. X-ray diffraction (XRD) technique and scanning electron microscope (SEM) were used to examine the crystal structure and surface morphology of the films. Optical transmission data were analyzed to obtain the optical band gap, dispersion parameters, and dielectric constants. The analyses showed that the films were polycrystalline in nature with the tetragonal rutile crystal structure. It was also observed that annealed films increased in thickness compared to the asdeposited samples. The Urbach tail width of the annealed sample also decresed from 293 to 252 meV indicating an improvement in crystallinity with heat treatment. The refractive index dispersion in the visible region analyzed in terms of long wavelength single-oscillator Sellmier approximation was in the range 1.9 -3.0. The zero and high-frequency dielectric constants were evaluated. The values of these constants could be a justification for further exploration of SnO2-based materials for charge storage and capacitive pressure sensing. Keywords: pyrolysis, dielectric, refractive index, thin film

<span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#252525;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">Influence of <span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#0F0F0F;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">nutritional <span style="font-size:14.0pt;line-height: 115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#3B3B3B;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">supp<span style="font-size:14.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#0F0F0F;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">lements <span style="font-size:14.0pt;line-height:115%; font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#252525;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">on keratinolysis by <i>Am</i><i><span style="font-size: 14.0pt;line-height:115%;font-family:"Times New Roman";mso-fareast-font-family: "Times New Roman";color:#4C4C4C;mso-ansi-language:EN-IN;mso-fareast-language: EN-IN;mso-bidi-language:HI" lang="EN-IN">yc<span style="font-size:14.0pt; line-height:115%;font-family:"Times New Roman";mso-fareast-font-family:"Times New Roman"; color:#252525;mso-ansi-language:EN-IN;mso-fareast-language:EN-IN;mso-bidi-language: HI" lang="EN-IN">olatopsis keratinophila</span></span></i></span></span></span></span></span>

870-874Keratinolytic potential of A. keratinophila (DSM 44409T) , a newly described  Amycolatopsis sp. isolated from cultivated soil in Kuwait, was demonstrated using keratinazure as the sole source of carbon and nitrogen as estimated by gel diffusion assay . Effects of 12 various nutritional supplements on the keratinolytic and azocollytic activities were determined .NH4H2PO4 and KNO3 in the medium supported a significantly higher keratinolytic activity than other supplements. However, azocollytic activities in all the supplemented media and the control were same. Best combination of carbon and nitrogen supplements (galactose and NH4H2PO4 respectively) used to evaluate the dynamics of growth and enzymes (keratinase and protease) activities of the isolate revealed a luxuriant growth with optimal keratinolytic activity occurring during the log phase. Other parameters of the fermentation medium, including pH, biomass accumulation, total protein and free amino acid concentrations were also studied

Study of Surface Modification of Electrospun Polyethylene Oxide Composite Fibre

Functionalization of polymers had gained attention because of advance applications as sensor, energy devices, membrane, etc. This present study is aimed at studying surface modification as a result of electrospinning functionalized polyethylene oxide (PEO) with zinc ion Zinc chloride was added in various proportions to PEO solution then electrospun at various voltage. Fibres resulted into various shapes; belt, rod, mat and thread which differs from the primary PEO. The mechanism for the morphology modification was studied and the optimum conditions which retain the fibrous morphology were noted. This functionalized PEO can be used as energy device. Keyword: Polyethylene oxide, Modification, Fibre, Composite, Functionalize

Tuning the optical properties and some surface structure of Cd-O thin film electrodeposited by two-electrode: An effect of Cobalt incorporation

The tuning of optical and dielectric parameters, structural and microstructural properties of CdO synthesized via a solution growth two-electrode cell arrangement under ambient environment, with the incorporation of Co ion into its matrix was investigated. The energy band gaps of the films was estimated in the range of 1.69 eV</=Eg</= 1.96 eV. The extinction coefficient, k for all the samples decreases as the incident photon energy increases. The films exhibit considerably high optical conduction across the photon energy with estimated power of 1013 (Omega m)-1. The elemental composition of the samples was determined using the energy dispersive x-ray spectrometry technique. The micrograph images from scanning electron microscopy technique shown that the films are polycrystalline and well-adhered to the substrates with their crystal grains evenly dispersed across the substrates’ surface. The x-ray diffraction analysis confirmed that the deposited films are of polycrystalline in nature. The films show preference for orientation along the (111) plane