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Search Results: 1 - 10 of 144569 matches for " F. Opara "
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Effect of Concentration on the Optical and Solid State Properties of ZnO Thin Films Deposited by Aqueous Chemical Growth (ACG) Method  [PDF]
S. L. Mammah, F. E. Opara, F. B. Sigalo, S. C. Ezugwu, F. I. Ezema
Journal of Modern Physics (JMP) , 2012, DOI: 10.4236/jmp.2012.39124
Abstract: Thin films of Zinc Oxide (ZnO) having different concentrations were deposited using the Aqueous Chemical Growth (ACG) method. The films were characterized using Rutherford Back Scattering (RBS) spectroscopy for chemical composition and thickness, X-Ray Diffraction (XRD) for crystallographic structure, a UV-VIS spectrophotometer for the analysis of the optical and solid state properties which include spectral absorbance, transmittance, reflectance, refractive index, direct band gap, real and imaginary dielectric constants, absorption and extinction coefficients and a photomicroscope for photomicrographs. The average deposited film thickness was 100 nm. The results indicate that the values of all the optical and solid state properties investigated vary directly with concentration except transmittance which is the reverse. Thus, the optical and solid state properties of ZnO thin film deposited by the Acqueous Chemical Growth method can be tuned by deliberately controlling the concentration of the precursors for various optoelectronic applications including its application as absorber layer in solar cells.
Annealing Effect on the Solid State and Optical Properties of αFe2O3 Thin Films Deposited Using the Aqueous Chemical Growth (ACG) Method  [PDF]
S. L. Mammah, F. E. Opara, F. B. Sigalo, S. C. Ezugwu, F. I. Ezema
Materials Sciences and Applications (MSA) , 2012, DOI: 10.4236/msa.2012.311115
Abstract: Thin films of hematite (α-Fe2O3) were deposited by heteronucleation through the process of hydrolysis and condensation of an aqueous solution of 0.1 M Fe (NO3)3.9H2O, 1 M NaNO3, 50 ml H2O in addition with five drops of HCl at 90℃. One of the samples was kept as prepared while the others were annealed at different temperatures in order to determine the effect of annealing on their solid state and optical properties. The films were characterized using Rutherford Back Scattering (RBS), spectroscopy for chemical composition and thickness, X-Ray Diffraction (XRD) for structural analysis, UV-VIS Spectrophotometer for the analysis of other solid state and optical properties and a photomicroscope for photomicrographs. The results indicate that while the absorbance and absorption coefficient decreases with increasing annealing temperature, the direct band gap and refractive index increases with increasing annealing temperature in the direction of increasing photon energy in the visible range. Also, there is a high infrared transmittance which increases with increasing annealing temperature and a shift/decrease in peak value of all the optical properties except transmittance in the direction of increasing photon energy as annealing temperature increases. The results further indicate that ACG hematite thin film annealed at 632K is a suitable metal oxide semiconductor material for photocatalytic applications. It is also suitable for use in the construction of poultry houses for the rearing of chicks because of its high infrared transmittance including other opto-electronic applications.
Model of Radiation Transport at Cosmic Ray Shocks
F.B. Sigalo,F.E. Opara
Research Journal of Applied Sciences , 2012, DOI: 10.3923/rjasci.2012.391.396
Abstract: Using a framework of the radiation approximation followed by a two-term perturbation expansion for cosmic ray transport in the spherical polar coordinates (r, θ, φ) researchers identify the effect of cosmic ray radiation on shock dominated transport. When the buoyancy parameter Fr is negligible, researchers find that the cosmic ray density at shock boundary (En) decreases with increasing temperature. It is also observed that the variation of radiation parameter N in cosmic ray transport has no significant effect in the temperature distribution. Thus, even when radiation is significant, it does not really modify the temperature within the cosmic ray region. However, for increases in the density at shock boundaries say (En), the temperature distribution decreases.
Performance of Some Plant Extracts and Pesticides in the Control of Bacterial Spot Diseases of Solanum
E.U. Opara,F.T. Obani
Agricultural Journal , 2013, DOI: 10.3923/aj.2010.45.49
Abstract: Pot trials were conducted at Michael Okpara University of Agriculture Umudike, Abia State, Nigeria to investigate the performance of four plant extracts (Azadirachta indica, Garcinia kola, Zingiber officinale and Allium sativum) and three synthetic pesticides (furadan, benomyl and streptomycin sulphate) for the control of bacterial leaf spot of two varieties of Solanum (S. gilo and S. torvum). The experiment was laid out in a Completely Randomized Design (CRD) and replicated three times. The results showed that A. indica and Z. officinale at 5 g L-1 were as good as the synthetic pesticides such as benomyl (0.1 g L-1) in reducing bacterial leaf spot disease severity of the two varieties; S. gilo (2.52) and S. torvum (3.48) in contrast with the control experiment, water (4.94-5.52). In this study, some plant extracts can serve as alternatives to the synthetic pesticides in the control of bacterial leaf spot disease of Solanum without any adverse effect on crop yield and yield parameters. The use of plant extracts therefore can be recommended to farmers considering their environmentally friendliness and availability.
Performance of Some Plant Extracts and Pesticides in the Control of Bacterial Spot Diseases of Solanum
E.U. Opara,F.T. Obani
Agricultural Journal , 2013,
Abstract: Pot trials were conducted at Michael Okpara University of Agriculture Umudike, Abia State, Nigeria to investigate the performance of four plant extracts (Azadirachta indica, Garcinia kola, Zingiber officinale and Allium sativum) and three synthetic pesticides (furadan, benomyl and streptomycin sulphate) for the control of bacterial leaf spot of two varieties of Solanum (S. gilo and S. torvum). The experiment was laid out in a Completely Randomized Design (CRD) and replicated three times. The results showed that A. indica and Z. officinale at 5 g L-1 were as good as the synthetic pesticides such as benomyl (0.1 g L-1) in reducing bacterial leaf spot disease severity of the two varieties; S. gilo (2.52) and S. torvum (3.48) in contrast with the control experiment, water (4.94-5.52).
Studies and Characterization of Bacterial Spot Pathogen of Tomato Xanthomonas campestris PV Vesicatoria
E.U. Opara,F.J.C. Odibo
Journal of Molecular Genetics , 2013,
Abstract: Investigation was conducted in the laboratory to characterize, identify and determine the strains of bacteria responsible for bacterial spot disease of tomato in humid tropics of South Eastern Nigeria. The bacteria were isolated from infected tomato plant; leaf, fruit and seed and subjected to some standard bacteriological tests. The results of the cultural, physiological and biochemical analyses obtained showed that the bacteria isolated from bacterial spot lesions of tomato fruits, leaves and seed were gram negative, yellow aerobic rod shaped bacteria with a polar flagella. The bacteria colonies exhibited strong starch hydrolysis, metabolized glucose and produced acid from arabinose, sucrose and cellobiose but not from ducitol or sorbitol. Also nitrite was not reduced to nitrite based on bacteriological characteristics, the bacteria strains were identified as Xanthomonas campestris pv. vesicatoria (ex Doidge). The pathogens were found to be influenced by temperature with optimum temperature of 30-32°C but little or no growth at 20 and 45°C.
DEVELOPMENT OF EMBEDDED SOFTWARE FOR FLOWSTATION METERING USING VB.NET WITH MCCDAQ BOARD: A CASE STUDY OF PETROLEUM TRAINING INSTITUTE (PTI) DEMONSTRATION FLOWSTATION
F. K. Opara,G. N. Okorafor.,C. S. Ikpeazu
Academic Research International , 2012,
Abstract: This paper presents a case study of converting an old pneumatic metering system of a Flowstation to a new system for digital display on a large screen. An analysis of the existing instrumentation system was carried out, and appropriate hardware and software platforms were selected. The system software was developed with MS Visual Studio 2010 and MS Access 2007. The Software system was tested with McDaq demo Board and the result was successful and satisfactory.
A REVIEW OF DIVERSITY TECHNIQUES FOR WIRELESS COMMUNIATION SYSTEMS
C. K. Agubor,F. K. Opara,G. N. Eze
Academic Research International , 2013,
Abstract: Wireless communication technology is now popular worldwide and has made mobile communication very attractive and in high demand. For higher data rates to meet the ever increasing demands in mobile communications, multiple-input multiple-output (MIMO) technology has been standardized as the 4G communication systems. MIMO, a wireless communication system which utilises multiple antennas at bothsides of the transmission link, has received high attention in the last few decades due to its ability to achieve high data rate transmission. Several papers have presenteddifferent techniques in the implementation of MIMO wireless systems which include diversity methods. Physical diversity is one of these methods that is well known and can be used to combat multipath fading, a common problem in wireless communications. This paper summarizes physical diversity as well as virtual diversity techniques. The paper shows that unlike the former, virtual diversity methods such asco-operative diversity and multiuser diversity are techniques that are implementable at the network or link layer of a wireless communication system.
INTELLIGENT SYSTEMS, MODELLING, SIMULATIONS AND THE APPLICATIONS
Opara F. Kelechi,Nwaogwugwu, C. Nnanyereugo,Okorafor G. Nwaji
Academic Research International , 2013,
Abstract: The need for Intelligent Systems (ISs) in the world today cannot be overemphasized. An intelligent system is a system that learns how to act in order to reach its main objectives. Its action usually gears towards maximizing the probability of success and minimizing the probability of failure. Modeling an intelligent system usually involves studying a natural system which it intends to mimic and designing the model based on related parameters. This report presents a general overview of intelligent systems, a simple block diagram model of an intelligent system, a flow of its internal processes, the simulation overview, and then some applications.
Sex Variability in Pediatric Leukemia Survival: Large Cohort Evidence
L. Holmes,J. Hossain,M. desVignes-Kendrick,F. Opara
ISRN Oncology , 2012, DOI: 10.5402/2012/439070
Abstract:
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