oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 70 )

2018 ( 462 )

2017 ( 452 )

2016 ( 589 )

Custom range...

Search Results: 1 - 10 of 285828 matches for " F. E. Opara "
All listed articles are free for downloading (OA Articles)
Page 1 /285828
Display every page Item
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.
Thermal Conductivity of Reinforced Cement Stabilized Lateritic Brick
V.B. Omubo-Pepple,F.E. Opara,C. Ogbonda
Journal of Engineering and Applied Sciences , 2012, DOI: 10.3923/jeasci.2010.178.180
Abstract: This study presents an experimental study carried out to determine the thermal conductivity of reinforced cement used as construction materials. The thermal conductivity was determined using the Resistance to Thermal Shock method. It was shown that the effect of incorporation of periwinkle shell (sea shells) results to the decreasing of the thermal conductivity and density. It was also obtained that the thermal conductivity as a function of time increases slightly between 11.00-12.00 pm in a sunny day for the lateritic brick.
Inhibition of Pathogenic Microorganisms by Ethnobotanical Extracts of Fruit Peels of Musa paradisiaca
Okechukwu R. I., Onyedineke N. E., Mgbemena I. C., Opara F. N. and Ukaoma A. A.
Journal of Applied Pharmaceutical Science , 2012,
Abstract: Ethanolic and water extracts of fruit peels of Musa paradisiaca were investigated for antimycotic activities and phytochemical properties on Trichophyton rubrum, T. mentagrophytes,Microsporum canis, Microsporum audouninii and Epidermophyton floccosum. The phytochemial analysis revealed that saponins, alkaloids, phenols, flavonoids and tannins were the active compounds. The agar diffusion method was used to assay for the antifungal properties on the test isolates the standard drug used was fluconazole. The results showed that the extract at different concentrations inhibited the growth of all the test isolates. The ethanolic extract was more effective than the water extract of the plant and zones of inhibition increased with increasein concentration of extract the result of this investigation demonstrate the potentials of Musa paradisiaca extracts as a source of chemotherapeutic agent that could be harnessed for use inhealth care delivery. This work also authenticates the use of Musa paradisiaca in traditional soap production which is used by some people to treat skin infections.
Choice of skin incision for a massive ovarian cyst  [PDF]
H. Annamraju, R. Rehman, E. Opara
Open Journal of Obstetrics and Gynecology (OJOG) , 2013, DOI: 10.4236/ojog.2013.37A1003
Abstract:

We present a case of a very large ovarian cyst extending up to the patient’s xiphisternum, which was managed through a Pfannensteil incision. The cyst was excised without any spill of fluid, using a5 mmlaparoscopic port under suction, through a Pfannensteil incision. By this method, the operating time and the post-operative in-patient stay were reduced. Also, as our patient had a very high BMI, the associated morbidity was significantly reduced.

Petrology and Geochemistry of Basement Complex Rocks in Okom-Ita Area, Oban Massif, Southeastern Nigeria  [PDF]
Kelechi Denis Opara, Young E. Obioha, Samuel Okechukwu Onyekuru, Chikwendu Okereke, Sabinus Ikechukwu Ibeneme
International Journal of Geosciences (IJG) , 2014, DOI: 10.4236/ijg.2014.54038
Abstract:

The determination of the mineralogical composition of rocks that underlie Okom-Ita area, in Oban Massif became necessary for the interpretation of the petrogenesis and protoliths of rocks in the area. Twelve representative rock samples were selected for thin section petrography and bulk rock geochemical analysis. The results reveal that the dominant intrusive rocks in Okom-Ita area are pegmatites, quartz veins and dolerites emplaced within gneisses, schists and phyllites host rocks. The quartz veins and pegmatites are leucocratic consisting predominantly of quartz, plagioclase and subordinate amount of Muscovites. The dolerite is dark grey, fine to medium grained and texturally ophitic and consists dominantly of pyroxenes, olivine and opaques. Three varieties of gneisses were recognized: feldspathic, banded and biotite gneisses. The gneisses, schists, and phyllites are dominated by SiO2 in the range of (60% - 75%). The rocks exhibit higher molecular concentration {Al2O3 > (CaO + Na2O + K2O)}, high alkali concentration with Na2O > K2O, high Al2O3 to alkali ratios and low TiO2, CaO and MgO concentrations. These distribution trends suggest a compensation for the high silica and alumina concentrations and support a granitic protolith for the pegmatites and their host gneisses and schists. The dolerites and amphibolites are impoverished in SiO2, but relatively enriched in

Page 1 /285828
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.