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Search Results: 1 - 10 of 111875 matches for " Ephrem O. Chukwuocha "
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Theoretical Studies on the Effect of Confinement on Quantum Dots Using the Brus Equation  [PDF]
Ephrem O. Chukwuocha, Michael C. Onyeaju, Taylor S. T. Harry
World Journal of Condensed Matter Physics (WJCMP) , 2012, DOI: 10.4236/wjcmp.2012.22017
Abstract: Quantum confinement effect in semiconductor quantum dots (QD's) of CdSe, ZnS and GaAs has been studied using the Brus Equation. It is found that the simple models obtained for the three different semiconductor nanocrystals exhibit the size dependence predicted by the particle-in-a-box model. The result shows that ground state confinement energy is inversely proportional to the size (radius). Thus, as one increases the radius (size), the confinement energy decreases, but never reaches zero. i.e., the lowest possible energy for the quantum dot sample is not zero.
New Trends in Corrosion Analysis of Al-Sn Alloy Duplex System  [PDF]
Chinedu Ekuma, Eziaku Osarolube, Ephraim O. Chukwuocha, Michael C. Onyeaju
World Journal of Condensed Matter Physics (WJCMP) , 2011, DOI: 10.4236/wjcmp.2011.12006
Abstract: The corrosion characterization of binary Al – Sn alloy systems has been statistically analyzed in the light of developed model equations. It was observed that the modeled corrosion penetration rate values generated using the developed model equations are in tandem with the experimental values.
Optoelectronic Characterization of Chemical Bath Deposited CdxCo1-xS Thin Film  [PDF]
Chinedu E. Ekuma, Mishark N. Nnabuchi, Eziaku Osarolube, Ephraim O. Chukwuocha, Michael C. Onyeaju
Journal of Modern Physics (JMP) , 2011, DOI: 10.4236/jmp.2011.29119
Abstract: Cadmium Cobalt Sulphide (CdxCo1-xS) thin film was deposited on microscopic glass substrate using chemical bath deposition technique at room temperature from aqueous solutions of Cadmium Chloride, Cobalt Chloride and Thiourea in which ammonium solution was used as complexing agents. The optical properties were characterized using the absorbance and transmission measurement from Unico UV-2102 PC spectrophotometer, at normal incidence of light in the wavelength range of 200 - 1000 nm. We report the deposition and optimization of the growth parameter with respect to time which showed that the band gap energy and the composition verified from the extended Vegard’s law are highly dependent on deposition time. The average transmittance of the film in VIS-NIR region ranges between 30% and 78% with absorbance range of 0.15 - 0.47 within the same wavelength range. The film was also observed to exhibit poor reflectance (11 < R% < 20) which declined albeit exponential within the entire studied wavelength range. From absorbance and transmittance spectra, the band gap energy determined for the film deposited at various time: 19 h, 21 h and 24 h are 2.25 eV, 2.17 eV and 2.05 eV respectively, in that order. The composition of the ternary system for 19 h; 21 h, and 24 h were found to be (x = 0.75; 0.83 and 0.94), respectively. Other optical and dielectric properties of the films were also characterized. Based on the exhibited properties of the film, it can be concluded that it is a promising material for selective coatings for solar cells; effective coatings for poultry houses; use as antireflective coating materials, and for fabrication of optoelectronic devices.
A Model Third Order Phase Transition in Fe-Pnictide Superconductors
Ekuma C. E.,Chukwuocha E. O.
Progress in Physics , 2012,
Abstract: By identifying the orders of phase transition through the analytic continuation of the functional of the free energy of the Ehrenfest theory, we have developed a theory for studying the dependence of the local magnetic moment, M on the Fe – As layer separation in the third order phase transition regime. We derived the Euler – Lagrange equation for studying the dynamics of the local magnetic moment, and tested our model with available experimental data.
Vulnerability Studies of Sensitive Watershed Areas of Owerri South East Nigeria Using Digital Elevation Models  [PDF]
Ngozi AC-Chukwuocha, Sabastine Amauche Ngah, Akajiaku C. Chukwuocha
Journal of Geoscience and Environment Protection (GEP) , 2017, DOI: 10.4236/gep.2017.510001
Abstract: The impact of human activities on sensitive watershed terrains is a critical consideration in the management of urban ecosystems. Degradation of sensitive ecosystem features such as watershed land areas is often irreversible due to the extent and intensity. The vulnerability of 150 m watershed management zone of Otamiri river Owerri Imo State, Nigeria was studied by topographic analysis using 1977 digital elevation model (DEM), 1977 aerial photos, Shuttle Radar Topographic Mission DEM of 2000, 2012 satellite imagery and the 2016 Master Plan of the study area. The impact of human activities in elevation change was observed in the parts of substantial human activities while topographical stability was recorded for areas of very low human activities.
Comparative properties of ceramic-based roofing sheets from local raw materials synthetic products after heat treatment
E. Chukwuocha
Journal of Applied Sciences and Environmental Management , 2002,
Abstract: Ceramic roofing sheets were fabricated in the laboratory by using ideal raw materials. The fabricating materials are coiled coconut fibre, palm fruit fibre, fresh water, river sand, polymeric dust, saw dust and cement. The resulting product was compared with factory -produced ceramic-based roofing sheets that are easily available in the Nigerian market. Both materials were of similar compositions except the mode of introduced polymeric materials. Samples of both materials were characterized in terms of rate of water absorption, density and breaking load. The properties of the materials show that the introduction of the polymeric dust at the fabrication stage and heat-treatment within the polymeric organic solution tremendously improved the quality of the ceramic-based roofing sheets. There was no significant difference on the quality of both samples. However, the total cost of production for the heat-treated finished production was relatively higher than the samples that were directly fabricated with polymeric dust as the dopant. (Journal of Applied Sciences & Environmental Management: 2002 6(2): 33-36)
Rapid assessment of home management of malaria among caregivers in parts of south eastern Nigeria
U Chukwuocha
Pan African Medical Journal , 2011,
Abstract: Background: This study was carried out to rapidly access the practice of home management of malaria by caregivers and community health workers in a rural part of South Eastern Nigeria between March and October, 2010. Methods: Structured, pretested questionnaires, focus group discussions and oral interviews were used to collect data from 300 consenting individuals. Results: Most of the participants/respondents were civil servants/teachers (44.3%). About 88.3% of them recognized malaria as an illness, 81.0% perceived it was transmitted by mosquito bites. Malaria diagnosis at home was mainly by noticing fever, headache, cough, and pains (86.0%). Most primary action was sought by going to hospitals/health centers (62.3%) and choroquine (46.7%) was the preferred antimalarial drug. Some of the factors hindering effective home management of malaria in the area included ignorance (13.0%); use of fake drugs (50%) and wrong diagnosis (19.1%). Conclusion: This study shows that there is some awareness about malaria and its management in the study area. There is however need to improve and sustain the strategy, placing more emphasis on educating the people on current drug protocols to achieve better results in controlling and combating malaria especially at the local levels.
$C^*$-algebra of the $\mathds{Z}^n$-tree
Menassie Ephrem
Mathematics , 2011,
Abstract: Let $\Lambda = \mathbb{Z}^n$ with lexicographic ordering. $\Lambda$ is a totally ordered group. Let $X = \Lambda^+ * \Lambda^+$. Then $X$ is a $\Lambda$-tree. Analogous to the construction of graph $C^*$-algebras, we form a groupoid whose unit space is the space of ends of the tree. The $C^*$-algebra of the $\Lambda$-tree is defined as the $C^*$-algebra of this groupoid. We prove some properties of this $C^*$-algebra.
Characterizing Liminal And Type I Graph C*-Algebras
Menassie Ephrem
Mathematics , 2002,
Abstract: We prove that the C*-algebra of a directed graph $E$ is liminal iff the graph satisfies the finiteness condition: if $p$ is an infinite path or a path ending with a sink or an infinite emitter, and if $v$ is any vertex, then there are only finitely many paths starting with $v$ and ending with a vertex in $p$. Moreover, C*(E) is Type I precisely when the circuits of $E$ are either terminal or transitory, i.e., $E$ has no vertex which is on multiple circuits, and $E$ satisfies the weaker condition: for any infinite path $\lambda$, there are only finitely many vertices of $\lambda$ that get back to $\lambda$ in an infinite number of ways.
Invasive neuroendocrine tumor of the kidney: a case report
Ephrem O. Olweny,Michael H. Hsieh,Jill C. Buckley,Jack W. McAninch
Rare Tumors , 2009, DOI: 10.4081/rt.2009.e37
Abstract: Neuroendocrine tumors (NETs) involve the genitourinary system in less than 1% of cases, with primary renal carcinoids comprising only 19% of reported genitourinary NETs (56 cases worldwide). We report a case of a renal NET presenting as a large renal mass with extensive local invasion, requiring definitive radical en bloc resection via a thoracoabdominal approach.
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