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Wavelength Dependent Nonlinear Spectroscopic Study of Third Harmonic Generation Probed by Rotational Maker Fringes Method

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Open Journal of Microphysics 2024年第2期14卷 13-23页

作者： Calford odhiambo Otieno Department of Physics Kisii University Kisii Kenya

Efficient third-order nonlinearities of the Zinc Oxide and Al-doped Zinc Oxide were studied by Third Harmonic Generation (Third Harmonic Generation) Maker fringes to establish the effect Aluminum of Aluminum doping (Al-doping) on the cubic nonlinearities. Adding the Al-dopant to the Zinc Oxide crystal structure results in changes that affect the optical and nonlinear characteristics. Presented results indicate that the magnitude of X(3) was enhanced at single experimental wavelengths;however, across the broadband experimental spectrum, the effect of Al-doping remained relatively constant. The observed enhancement of third-order nonlinearity was purely from the bound electronic response. The observation is attributed to increased charge carriers and spontaneous polarization in the Zinc Oxide and Al-doped Zinc Oxide crystal structure.

关键词： Nonlinear Optics Harmonic Generation Maker Fringes Zinc Oxide

Assessment of Groundwater Stability Using Corrosion and Scaling Tendency Indices on Selected Springs in the Manga Region in Nyamira County, Kenya

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Open Journal of Microphysics 2024年第3期14卷 79-88页

作者： Calford odhiambo Otieno Alice Makonjo Wekesa Physics Department Kisii University Kisii Kenya

We present the result of groundwater stability assessment on three major springs in the Manga region in Nyamira County found in Kenya in 2018. These springs are Kiangoso (SP1), Kerongo (SP2) and Tetema (SP3). The corrosion and scaling tendency indices were obtained using the Langelier saturation index (LSI), Ryznar stability index (RSI), and Puckorius scaling index (PSI). The LSI values obtained for SP1, SP2, and SP3 are −3.93, −4.71, and −4.17, respectively, while using RSI, the values obtained for SP1, SP2, and SP3 are 14.15, 14.53, and 13.74, respectively. Using PSI, the values of SP1, SP2, and SP3 are 5.58, 5.45, and 5.58, respectively. From the interpretation of the indices, the groundwater from the three springs in the Manga region using LSI and RSI showed intolerable corrosion;hence, it is unlikely to scale as obtained from PSI.

关键词： Langelier Saturation Index Ryznar Stability Index Puckorius Scaling Index

Spatio-Temporal Agricultural Drought Quantification in a Rainfed Agriculture, Athi-Galana-Sabaki River Basin

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Journal of Geographic Information System 2024年第4期16卷 201-226页

作者： Joe Ndundi Tete Godfrey Ouma Makokha Oscar Owino Ngesa John Ngugi Muthami Bonface Wabwire odhiambo Department of Informatics and Computing Taita Taveta University Voi Kenya Department of Finance and Economic Planning County Government of Kilifi Kilifi Kenya

This study employs a quantitative approach to comprehensively investigate the full propagation process of agricultural drought, focusing on pigeon peas (the most grown crop in the AGS Basin) planting seasonal variations. The study modelled seasonal variabilities in the seasonal Standardized Precipitation Index (SPI) and Standardized Agricultural Drought Index (SADI). To necessitate comparison, SADI and SPI were Normalized (from −1 to 1) as they had different ranges and hence could not be compared. From the seasonal indices, the pigeon peas planting season (July to September) was singled out as the most important season to study agricultural droughts. The planting season analysis selected all years with severe conditions (2008, 2009, 2010, 2011, 2017 and 2022) for spatial analysis. Spatial analysis revealed that most areas in the upstream part of the Basin and Coastal region in the lowlands experienced severe to extreme agricultural droughts in highlighted drought years. The modelled agricultural drought results were validated using yield data from two stations in the Basin. The results show that the model performed well with a Pearson Coefficient of 0.87 and a Root Mean Square Error of 0.29. This proactive approach aims to ensure food security, especially in scenarios where the Basin anticipates significantly reduced precipitation affecting water available for agriculture, enabling policymakers, water resource managers and agricultural sector stakeholders to equitably allocate resources and mitigate the effects of droughts in the most affected areas to significantly reduce the socioeconomic drought that is amplified by agricultural drought in rainfed agriculture river basins.

关键词： Agricultural Drought Food Security Standardized Precipitation Index Standardized Agricultural

Wavelength Dependent Nonlinear Spectroscopic Study of Third Harmonic Generation Probed by Rotational Maker Fringes Method

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Metallocene Catalyzed Homopolymerization of Propylene with a <i>C</i><sub>2</sub>Symmetric Isospecific Zirconecene/MMAO Catalysts under Different Polymerization Conditions

Open Journal of Microphysics（微观物理学期刊） 2024年第2期 13页

作者： Calford odhiambo Otieno

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Open Journal of Organic Polymer Materials 2020年第3期10卷 27-34页

作者： benard Oloo Nyangoye benard odhiambo Obondo Donghua University Shanghai China Masinde Muliro University of Science and Technology Kakamega Kenya

In this work, homopolymerization of propylene for synthesis of different molecular weights polypropylene was done using an isospecific metallocene catalyst by changing the polymerization conditions such as Al/Zr (Aluminium/Zirconium) ratio, temperature, pressure and polymerization time. The effects of the polymerization conditions on the molecular weight and other polymer properties have been discussed according to the results obtained. The results indicate that the activity of polymerization increased with increasing the Al/Zr mole ratio and reached a maximum value at a ratio of 2000. In relation to the mole ratio, the molecular weight also followed the same trend. The activity was also seen to increase with increase in temperature. The molecular weight increased with increasing the polymerization time at both 0°C and 25°C, but reduced with increase in time at 40°C. The increase of pressure also increased activity but lowered the molecular weight, indicating β-H elimination to the monomer.

关键词： Homo-Polymerization Activity Molecular Weight Molecular Weight Distribution (MWD)

Electrophoretic Deposition of TiO2/Nb2O5 Composite Electrode Thin Films for Photovoltaic Application

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Journal of Energy and Power Engineering 2014年第4期8卷 757-764页

作者： John Njagi Nguu Bernard odhiambo aduda Francis Wanjala Nyongesa Robinson Juma Musembi Department of Physics University of Nairobi Nairobi P.O.Box 30197-00100 Nairobi Kenya

Nano sized powders of TiO2 （titanium dioxide） and Nb2O5 （Niobium （V） oxide） were used to fabricate TiO2/Nb2O5 composites thin films by EPD （electrophoretic deposition） technique. The metal oxide powders, together with magnesium nitrate hexahydrate pellets, were suspended in propan-2-ol inside an EPD cell. The electrodes, placed 1.2 cm apart, were partially immersed in the suspension and a DC potential applied across them. Key EPD process parameters, which include applied DC electric field, deposition time and solid concentration in suspension, were optimized through visual inspection and from UV-Vis-NIR spectrophotometer spectra. The highest （55%） transmittance was obtained for films with deposition time of 90 s, powder concentration of 0.01 g/40 mL, and 35 V DC （direct current） voltage. XRD micrographs confirmed that TiO2 and Nb2O5 particles were presented in the composite film. SEM （scanning electron microscope） micrographs of the composite electrode thin films showed that porous films of high quality with well controlled morphology were deposited by using the EPD technique.

关键词： Electrophoretic deposition TiO2/Nb2O5 composite electrode thin films.

Organochlorine pesticide and heavy metal residues in some edible biota collected from Quanzhou Bay and Xinghua Bay,Southeast China

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Journal of Environmental Sciences 2010年第2期22卷 314-320页

作者： Mangala Yatawara odhiambo Joshua Owago Julia E Burnet Key Laboratory of Biogeology and Environmental Geology of Ministry of Education

In order to assess the contamination of edible marine organisms in Quanzhou and Xinghua Bays, Fujian Province, China, concentrations of organochlorine pesticides （hexachlorocyclohexane isomers or HCHs and dichlorodiphenyltrichloroethane isomers/derivatives or DDTs） and heavy metals （Cu, Pb, Zn, As, Cr, Cd, Ni and Hg） in 13 species collected from different sites in the hays were analyzed by GC-ECD and ICP-MS. The concentration of the sum of DDTs exceeded that the sum of HCHs in the samples. Most of the organisms showed higher levels of DDTs than the first level criterion （10 ng/g） for marine biological quality in China （GB 18421-2001） but conformed to the first level criterion （20 ng/g） for HCHs. The estimated mean daily uptake of pesticides was below the level for minimal risk to the consumers. The levels of Cd, As and Pb in most organisms from both bays were markedly elevated and above the recommended legal limits for human consumption. Our results showed the need for routine monitoring of marine species contamination to ensure public and environmental health.

关键词： organochlorine pesticides residue levels technical HCH heavy metals Fujian Province

The Role of the United Nations in Conflict Resolution of the Syrian War (2011-2020)

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The Role of the United Nations in Conflict Resolution of the...

作者： VALERIE ATIENO odhiambo 华中师范大学

学位级别：硕士

由于阿拉伯春季抗议活动,叙利亚的内战于2011年3月开始。这些是在阿拉伯国家发生的一系列抗议活动,反对当前政权。这些抗议活动始于2010年在突尼斯。然后后来到达叙利亚。叙利亚的政治稳定是有问题的,即使在战争爆发之前,前阿萨德接替...

由于阿拉伯春季抗议活动,叙利亚的内战于2011年3月开始。这些是在阿拉伯国家发生的一系列抗议活动,反对当前政权。这些抗议活动始于2010年在突尼斯。然后后来到达叙利亚。叙利亚的政治稳定是有问题的,即使在战争爆发之前,前阿萨德接替了他已故的父亲哈菲兹·阿萨德。叙利亚国防部长哈菲兹·阿萨德(Hafez al-Assad)于1970年被推翻为国家元首。他父亲去世后,他于2000年被巴沙尔·阿萨德(Bashar al-Assad)继任。在阿萨德(Assad)的统治下,叙利亚人民希望建立一个更好的国家,因为他们将阿萨德(Assad)视为朝着正确方向迈出的一步。但是,这被缩短了。结社和言论自由受到政府的压制。禁止聚会。经济走下坡路,只青睐精英阶层,而中产阶级则选择生存。然后是干旱,导致食物和水的短缺。那些以农业为生的人没有生计,被迫搬到市区谋生。这些都是引发战争的原因之一。到2011年3月,一群年轻人进行了反阿萨德涂鸦,后来被政府逮捕。政府官员对人民的虐待促使抗议活动流血。叙利亚战争随后引起了国际社会的注意。联合国成立于1945年,其宗旨是维持国际社会的和平与安全。该组织是国际联盟失败的结果。多年来,联合国在不同大陆的不同国家开展了维持和平行动,以恢复和平。联合国确保和平与安全的机构是维护和平并采取必要措施的机构。这符合《联合国宪章》第四十一条和第四十二条的规定。联合国对叙利亚战争的干预使国际社会有保证立即看到叙利亚战争的结束。然而,十年后,叙利亚内战仍在继续。这场战争需要这么长的时间才能解决,但采取了哪些错误措施?有流血事件。许多人丧生。一些叙利亚人为了安全起见不得不逃亡,现在他们是黎巴嫩等国家的难民。叙利亚国的未来尚不清楚。叙利亚人民正在逐渐失去对更美好明天的希望。显然,国际社会使叙利亚失败了。纵观战争,冲突中有许多参与者。伊朗火鸡;我们;俄罗斯。冲突未解决的原因之一。参与叙利亚冲突的国家只为自己的利益蒙蔽双眼,而不是为战争遗弃的国家寻求恢复和平的眼光。除此之外,在叙利亚问题上,联合国安理会成员也有利益冲突。美国和俄罗斯相互竞争,因为它们在冲突中支持冲突双方。俄罗斯支持阿萨德政府,而美国则支持反对派。这使叙利亚问题更加复杂。当联合国安理会,特别是常任理事国没有共同目标时,很难达到界限。本研究主题的原因;联合国在解决叙利亚内战冲突中的作用。本文试图理解为什么叙利亚战争已经持续了多年而没有任何解决的迹象。该论文考察了战前和战后叙利亚的历史。它定义了叙利亚和国际冲突中每一个参与者在国际冲突中所扮演的角色。然后,论文讨论了联合国对战争的干预及其所扮演的角色。对联合国在冲突中所发挥作用的评价将有助于我们找出为什么和平尚未恢复。联合国在处理冲突方面的效力值得怀疑。但是,一切并没有丢失。至少还没有。

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Size,efficiency,market power,and economies of scale in the African banking sector

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Financial Innovation 2019年第1期5卷 54-75页

作者： Simplice A.Asongu Nicholas M.odhiambo Department of Economics University of South AfricaP.O.Box 392Pretoria 0003South Africa Department of Economics&Development Studies Covenant UniversityOtaNigeria

There is a growing body of evidence that interest rate spreads in Africa are higher for big banks compared to small *** concern is that big banks might be using their market power to charge higher lending rates as they become larger,more efficient,and *** contrast,several studies found that when bank size increases beyond certain thresholds,diseconomies of scale are introduced that lead to *** that case,we also would expect to see widened interest *** study examines the connection between bank size and efficiency to understand whether that relationship is influenced by exploitation of market power or economies of *** a panel of 162 African banks for 2001–2011,we analyzed the empirical data using instrumental variables and fixed effects regressions,with overlapping and non-overlapping thresholds for bank *** found two key ***,bank size increases bank interest rate margins with an inverted U-shaped ***,market power and economies of scale do not increase or decrease the interest rate margins *** main policy implication is that interest rate margins cannot be elucidated by either market power or economies of *** implications are discussed.

关键词： Sub-Saharan Africa Banks Lending rates Efficiency Quiet life hypothesis Competition