Browsing by Author "Odhiambo, J.O."

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Effect of CuO2 plane on the thermodynamic properties of double Tl-O layered cuprate based on an interaction between cooper pair and an electron
(2016) Odhiambo, J.O.; Sakwa, T.W.; Rapando, B.W.; Ayodo, Y.K.
Electron interaction near the critical temperature is viewed as a contributor to the establishment of the energy gap which of late is projected to be a harbinger to explaining microscopic mechanism behind High temperature superconductivity. This study investigated the effects of the number of planes of CuO2 on the thermodynamic properties of double Tl-O layered compounds: Tl2Ba2CaxCuyOz (Tl22XY) High temperature superconducting cuprates due to an interaction between a Cooper Pair and an electron. The energy of interaction at the critical temperature (Tc) was seen to increase with increase in the number of CuO2 planes. The specific heat per unit mass, Sommerfeld coefficient as well as the entropy per unit mass, decreased with an increase in the number of CuO2 planes. The peak Sommerfeld coefficient temperature (T’) was noted to be approximately 0.66Tc in all considered cases of Tl22XY.
The effectiveness of coccinellids as natural enemies of aphids in maize, beans and cowpeas intercrop
(2012) Nyukuri, Robert W.; Kirui, Stella C.; Wanjala, Fred M.E.; Odhiambo, J.O.; Cheramgoi, Evelyne
Abstract: A field study was conducted in Busia district of Kenya to elucidate the dynamics of ladybirds in mixed stands of maize, beans and cowpeas to determine their efficacy as sole control measures for Aphids. Maize, beans and cowpeas were intercropped using conventional husbandry practices and the general Coccinellid quantified as follows: Colonies of four Coccinellids, starved for 12 hours to enhance feeding on Aphids were assessed. The effects of weather on the abundance of Coccinellids were also investigated and involved collection of meteorological data from the Busia District Agricultural Office (BDAO) and from Busia Farmers Training Centre (BFTC) and relating them to the abundance and predation values. The predator population was most abundant in the mixed stands of maize and beans (2.33 predators/30 Aphids) as compared to their occurrence in pure stands of cowpeas (0.85 predators/30 Aphids). The genus Cheilomenes spp. was the most ubiquitous predator with a mean of 4.00 individuals/30 Aphids while Hippodamia variegata was the least abundant predator species with a mean of 0.92 individuals/30 Aphids in all the agro-ecosystems. The larvae of Hippodamia variegata were the most bio-efficient, consuming 32.44 Aphids while their adults were the least bio-efficient, consuming 4.22 individuals for a period of 12 hours. The Coccinellids consumed more Aphids at higher aphid densities (24.05 Aphids) than at lower aphid densities (9.44 Aphids) over the same period of time. Rainfall and relative humidity had significant (F = 3.675; P < 0.05) effects on the abundance of Coccinellids. Temperature had significant (F = 3.58; P < 0.05) effect on the abundance of Coccinellids though at a lower level. Rainfall (r = -0.162) and relative humidity (r = - 0.084) were both inversely correlated with the abundance of Coccinellids. On the other hand, temperature was positively correlated (r = 0.159) with the prevalence of Coccinellids indicating that warmer and drier conditions favoured their multiplication. Key words: Efficacy, Coccinellids, Aphids, natural enemies, ecological factors, crops.
Effects of different agroecosystems on prevalence of different species of pests and coccinellid predators
(2012) Nyukuri, Robert W.; Wanjala, Fred M.E.; Cheramgoi, Evelyn; Odhiambo, J.O.; Kirui, Stella C.
Abstract: This study was aimed at determining the effects of mixed and single cropping agroecosystems on the prevalence of different species of insect pests and coccinellids. It involved six growing crops: maize Zea mays L., beans Phaseolus vulgaris L. and cowpeas Vignaunguiculata L. Walp in single and mixed stands and sampling throughout the phenology of the crops. Eight insect pest species were recorded on maize grown alone, while thirty seven insect species were endemic on cowpea mono cropped and were of six orders whereas twenty two insect pest species occurred on beans. The predator population was most abundant in the mixed stands of maize and beans (2.33 predators per 30 aphids) as compared to their occurrence in pure stands of cowpeas (0.85 predators per 30 aphids) as there were numerous aphids on beans at pre-flowering phase that supported a higher population level of coccinellids. Also, predator population was at the peak during the tussling stage of maize as they fed on the pollen grains while aphids on cowpeas co-existed mutualistically with black ants that protected them against predation. The genus Cheilomenes spp. was the most ubiquitous predator with a mean of 4.00 individuals per 30 aphids while Hippodamiavariegata was the least abundant predator species with a mean of 0.92 individuals per 30 aphids in all the agroecosystems as the Cheilomenes spp. had a faster discovery rate, range of perception, effective capture efficiency and a shorter handling time of a prey. Key words: Phenology, stands, Zea mays L., Phaseolus vulgaris L., Vignaunguiculata L. Walp, agroecosystem.
Effects of static electromagnetic fields at 24 hours incubation on the germination of rose coco beans (phaseolus vulgaris)
(2009-05) Odhiambo, J.O.; Ndiritu, F.G.; Wagara, I.N.
This study evaluates the percent germination of Rose coco beans (Phaseolus vulgaris L.) seeds, when exposed to static electromagnetic fields under laboratory conditions incubated for 24 h. This can be replicated in the field to aid short period production of beans, hence higher yield. For a given set of sample, germinating bean seeds were exposed to field generated by Helmholtz coil, North Pole or the South Pole with constant magnetic fields of 5 mT, 10 mT, 30 mT and 60 mT. The exposure period was fixed at 3, 4.5 and 6 h and exposed after 12 h incubation. The germinating seeds were counted after 24 h. Certain trends could be observed; statistical analysis has shown that there is statistical influence (p < 0.05, ANOVA test) of the magnetic treatment on germination of rose coco beans. Maximum seed germination occurred when exposed to South Pole field inducing percent germination of approximately 73% compared to 52% of the control at field strength of 30 mT at exposure period of 4.5 h. The research achieved its aim of proving the influence of static electromagnetic field to germination of seeds in addition to, challenging seed companies to come up with magnetized seeds that will germinate faster.
Gender disparity in education
(Oakland Books, 2004) Odhiambo, J.O.; Kirui, H.W.; Ndiritu, F.G.U.
Quality education is a fundamental right enshrined in the 1948 universal declaration of human rights. It is estimated that about 18% eligible children have never been enrolled in schools; about 62% of these eligible children are girls. Female gender (53%) outnumbers male gender and this should be reflected in the enrolment of students in schools countrywide. This is not the case because for instance in 1999, 48% of eligible girls were enrolled in primary school compared to 52% boys. At secondary school level, 46% of students enrolled were girls. In Kenya s six public universities, ladies comprise only 30% of the total student's population. There is a direct proportionality between development of a country and the education of its citizen. In the job market world wide, science still remains bastion of masculinity, the percentage of physicists who are women is hovering around 4%, ofchemists 8%, of engineers 2% and of biologists is 20%. This paper will attempt to explain the reasons behind gender disparity in science education and its effects in development of various sectors from political, agricultural, industrial, cultural and socio-economic point of view.
Optical characterization of atmospheric aerosols via airborne spectral imaging and self-organizing map for climate change diagnostics
(2018-08-03) Makokha, John W.; Odhiambo, J.O.
Self-Organizing Map (SOM) analysis is used to perform optical characterization of both Aerosol Optical Depth (AOD) and Ångström Exponent (ÅE) retrieved from Moderate-resolution Imaging Spectroradiometer (MODIS) in relation to Precipitation Rate (PR) from Tropical Rainfall Measurement Mission (TRMM) over selected East African sites from 2000 to 2014 and further diagnose climate change over the region if any. SOM reveals a marked spatial variability in AOD and ÅE that is associated to changing aerosol transport, urban heat islands, diffusion, direct emission, hygroscopic growth and their scavenging from the atmosphere specific to each site. Temporally, all sites except Mbita and Kampala indicate two clusters in AOD that are associated to prevailing dry and wet seasons over East Africa. Moreover, all sites except Mbita and Mount Kilimanjaro show two clusters in ÅE that are related to aerosol mode of generation and composition over the region. The single cluster in AOD and ÅE over Mbita indicate that aerosol characteristics over the site are influenced by biomass burning and local air circulation rather than the monsoon precipitation throughout the study period.
Quantum thermodynamics of a strongly interacting bose-fermi mixture in a three-dimensional anharmonic potential
(Researchgate, 2016) Mumali, O.W.; Ayodo, Y.K.; Ndinya, B.O.; Odhiambo, J.O.
Thermodynamic properties of Bose-Fermi mixture at ultra-low temperatures were studied using perturbation theory in three Cartesian coordinates. The Hamiltonian for the mixture was developed in terms of boson-boson, boson-fermion and fermion-fermion interactions. In both first and second excited states the mixture had about 150 joules of energy at about 40 kelvins. In both first and third excited states, the mixture had energy value of about 200 joules at a temperature of about 48 kelvins. The mixture had energy value of about 240 joules at about 58 kelvins in both the second and the third excited states. The specific heat capacity versus temperature curves showed sharp turning points with peak values of specific heat capacity being 11.58J/mol/ at about 6.9 kelvins for first excited state, 7.88J/mol/ at about 13.7 kelvins for second excited state and 6.758J/mol/ at about 20.9 kelvins for third excited state. Entropy of the BF mixture in an excited state was found to increase with temperature and became constant at higher temperatures.
Seasonal variability in aerosol microphysical properties over selected rural, urban and maritime sites in Kenya
(2018) Khamala, Geoffrey W.; Odhiambo, J.O.; Makokha, John W.
Atmospheric aerosols are posing a great threat to the already stressed climate with the effects being felt more on African continent. Their presence and interaction with the clouds contribute to the strongest uncertainty in aerosol characteristics and Earth’s energy budget hence; calling for a long term assessment to be done. The present study analyses long term spatiotemporal microphysical aerosol characteristics (namely: effective radius (eff r) and surface-area concentration), using AErosolROboticNETwork (AERONET) framework over Kenyan urban atmosphere (Nairobi-1 S, 36 E), rural atmosphere (ICIPE-Mbita-0 S, 34 E) and maritime atmosphere (CRPSM-Malindi-2 S, 40 E). AERONET framework was used due to its availability over the selected sites; it is also located in sites that provided contrasting aerosols type, source and characteristics and due to its synergism with other frameworks. The findings indicated a spatial and temporal variability in microphysical properties over CRPSM-Malindi, Nairobi and ICIPE-Mbita. CRPSM-Malindi is dominated with coarse aerosols in all seasons while Nairobi with coarse mode in the DJF and MAM seasons. ICIPE-Mbita is on the other hand dominated with fine aerosols in all season. In terms of size distribution, the three AERONET sites displayed a bimodal distribution inflecting at 0.44 µm and fine mode radius of 0.15 µm while CRPSM-Malindi recorded a coarse mode of 3.86 µm and Nairobi and ICIPE-Mbita with 5.06 µm. The coarse aerosols have a higher concentration than the fine aerosols in all AERONET sites because of aerosol coagulation and dominance of certain type of aerosols that are coarse.
Spatial-temporal characterization of atmospheric aerosols via airborne spectral imaging and growing hierarchical self-organizing maps
(Scientific Research Publishing, 2018-06-25) Makokha, John W.; Odhiambo, J.O.
Neural network analysis based on Growing Hierarchical Self-Organizing Map (GHSOM) is used to examine Spatial-Temporal characteristics in Aerosol Optical Depth (AOD), Ångström Exponent (ÅE) and Precipitation Rate (PR) over selected East African sites from 2000 to 2014. The selected sites of study are Nairobi (1˚S, 36˚E), Mbita (0˚S, 34˚E), Mau Forest (0.0˚ - 0.6˚S; 35.1˚E - 35.7˚E), Malindi (2˚S, 40˚E), Mount Kilimanjaro (3˚S, 37˚E) and Kampala (0˚N, 32.1˚E). GHSOM analysis reveals a marked spatial variability in AOD and ÅE that is associated to changing PR, urban heat islands, diffusion, direct emission, hygroscopic growth and their scavenging from the atmosphere specific to each site. Furthermore, spatial variability in AOD, ÅE and PR is distinct since each variable corresponds to a unique level of classification. On the other hand, GHSOM algorithm efficiently discriminated by means of clustering between AOD, ÅE and PR during Long and Short rain spells and dry spell over each variable emphasizing their temporal evolution. The utilization of GHSOM therefore confirms the fact that regional aerosol characteristics are highly variable be it spatially or temporally and as well modulated by PR received over each variable.
Thermodynamic properties of an interaction between cooper pairs and electrons in bismuth based cuprate superconductivity
(KIBU, 2017-06-15) Odhiambo, J.O.; Sakwa, W.T.; Ayodo, K.Y.; Makokha, J.W.
A theoretical study considering Bi2201, Bi2212 and Bi2223 bismuth based cuprates whose critical Temperatures (TC) are 20K, 95K and 110K with one, two and three CuO2 planes respectively; based on an interaction of Cooper pair and an electron in Bismuth based cuprates oxide shows that there is a direct correlation between energy of interaction and the number of CuO2 planes at the TC. The specific heat for a mole of Bismuth based cuprates at TC was found to be 7.471×10 −24J𝐾 −1 regardless of the number of CuO2 planes; though the specific heat per unit mass, Sommerfeld coefficient as well as entropy per unit mass decreased with an increase in the number of CuO2 planes. The entropy of a mole of Bismuth based cuprates at TC was found to be 5.603×10−24𝐽𝐾−1 irrespective of the TC or mass. The peak Sommerfeld coefficient temperature was noted to occur at the ratio T/TC=0.66 in the bismuth based cuprates.
Thermodynamic properties of mercury based cuprate due to Cooper pair-electron interaction
(JMEST, 2016-07) Odhiambo, J.O.; Sakwa, T.W.; Ayodo, Y.K.; Rapando, B.W.
Interaction between electrons at the critical temperature that culminates into formation of Cooper pair holds the key in explaining cuprates high temperature superconductivity. We study the effects of the number of copper oxide planes on thermodynamic properties of Mercury based high temperature superconductivity due to an interaction between cooper pair and electrons. We noted that the energy of interaction at the critical temperature was seen to increase with increase in the number of copper oxide planes. The specific heat, Sommerfeld coefficient and the entropy per unit mass, decreased with an increase in the number of copper oxide planes. The peak Sommerfeld coefficient temperature was noted to be approximately 0.66 times critical temperature in all considered cases of mercury based cuprates.