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Recent Submissions

Effect of Product Design on Operational Performance of Sugar Firms in Kenya.
(International Journal of Scientific Research and Engineering Development, 2023-07-04) Joseph, K. O.; Washington, Albert; Tambo, Ochung; Aliata, Victor L.
Product design is a key indicator of a successful operational performance realization and is gaining robust momentum among Sugar Firms as a survival and growth strategy. The Sugar Firms in Kenya contribute approximately 26% directly to the Gross Domestic Product (GDP) and an additional 25% indirectly through agro-based and associated industries linkages. However, they have experienced a significant decline of milled sugar production from about 635,700 tonnes in 2015 to 491,100 tonnes in 2018 according to Kenya National Bureau of Statistics in 2019. This decline was mainly attributed to the high cost of production stemming from inefficiencies across the value chain from inadequate research and extension leading to the design of production systems that are inefficient. Despite the vast contribution of the Sugar Firms to the economy, this problem of inefficient production system has not been solved and thus the Sugar Firms performance continues to spiral downward leading to the dissolution of some firms, downscaling of operations etc. Reviewed the studies also, established a weak relationship between product design and operational performance and warrants investigation. It is in this regard that this study purposes to establish the effect of product design on operational performance of Sugar Firms in Kenya. The research was guided by the resource-based view theory and transaction cost theory. A census survey was conducted targeting all 164 managers and assistant managers of Sugar Firms in Kenya. A pilot study was conducted of 14 participants constituting of managers and assistant managers of seven departments in Transmara Sugar Company to test for reliability using Cronbach‘s alpha, with a threshold of 0.70, indicating satisfactory instrument reliability. The Cronbach's Alpha reliability coefficient obtained in this study was 0.849. Primary data was collected using questionnaires. A multiple linear regression model was applied to establish the association among explanatory variables in this study. The results established that product design significantly affects operational performance (β =0.742, p=.000), hence, adoption of a one-standard deviation increase in product design yields a significant 0.742 unit increase in operational performance for Sugar Firms. Indicating a positive and significant association between the two variables. Hence, the study offers a products design model that can assist in enhancing operational performance
Thermodynamics of a Grand-canonical Binary System at Low Temperatures
(The Centre for Info Bio Technology, 2013-06) Sakwa, Thomas W.; Ayodo, Y. K.; Sarai, K.; Khanna, K. M.; Rapando, B. W.; Mukoya, A. K.
The ground state properties of trapped atomic Boson-Fermion mixture at near absolute zero temperature Kelvin is studied using second quantization techniques. An effective Hamiltonian for the Binary system is developed in terms of the magnitude of fluctuations to bring out the interplay between boson-boson, boson-fermion & fermion-fermion interactions and their implications on the thermodynamics properties of the system. The study focused on a Grand Canonical Binary system of 3He4He isotopes whose thermodynamic properties have been determined by distinctively singling out the boson-boson, bosonfermion, and fermion-fermion interactions from which the energy density is established algebraically. The specific heat and the entropy of the system were consequently established and analyzed. The total energy of the system is found to increase with increase in occupation number of the system. The jump in the specific heat seems to suggest a phase-like transition at temperature of about 0.4K. Entropy decreases with temperatures.
Computer Modeling for Science, Technology, Engineering and Mathematics Curriculum in Kenya: A Simulation-Based Approach to Science Education
(Science Publishing Group, 2016-01-09) Sifuna, James; Manyali, George; Sakwa, George W.; Mukasia, Alima
Developed countries have appreciated the importance of Science, Technology, Engineering and Mathematics (STEM) for scientific and technological development. STEM subjects have been posting low results in the Kenya Certificate of Secondary Examinations over the years and we have linked the deteriorating standards to the inappropriate teaching approaches that mainly tend to be teacher-centered and hence compromising the learner-centered approach. Due to the poor teaching methods, we ought to incorporate simulation in science education to foster good grades and this formed the basis of this research. Computation techniques have been applied in many subject areas in tertiary institutions with promising results that tend to be in agreement with experimental data. Our research is a quasi-experimental study and thus we have employed the Solomon-Four-Quasi-Experimental design that enabled us to involve a comparison between two computational groups and two control groups. The control groups served to reduce the influence of confounding variables and allowed us to test whether the pre-test had an effect on our objective. Purposive sampling technique was used to select three schools (A boy school, a girl school and a mixed sex school). Each school was expected to have a computer for simulation. The three schools were further split into four groups (single boy’s school, single girl’s school, boys from the mixed and girls from the mixed school). Each school provided the form one class and a total of 150 students participated. We taught the concept of the periodic table to all the students, the computational groups were taught using the simulations while the control groups were taught using the regular methodology. After we had taught for a period of one month, all the four groups were tested using a tool verified by Kurder-Richardson 21 Formula and the data analyzed using t-test, ANOVA and Origin 9.0. The results showed that the computation groups posted higher scores in the concept of the periodic table. This research points to the fact that there is an urgent need to re-design the teaching of Science, technology, Engineering and Mathematics fields, by incorporating computation techniques to enhance STEMs.
Structural and Mechanical Properties of Bulk Scandium Trifluoride Investigated by First-principles Calculations
(2017-02-28) Sifuna, James; Manyali, George; Sakwa, Thomas W.; Kitui, Manasse
Cubic Scandium Triflouride (ScF3) is a material that contracts when exposed to heat. Not many materials are known to behave this way. Such a material has many interesting technological applications yet some of its properties are yet to be fully explored using ab initio methods. This paper engaged the state-of-the-art ab initio methods to study the Structural and Mechanical properties of ScF3 at ambient conditions. All calculations were done within the Density Functional Theory (DFT) framework and a plane wave basis set as implemented in the QUANTUM ESPRESSO computer code. A comparison with previous DFT and Experimental studies was done. The Projector Augmented Wave pseudo-potentials were used to describe the core-valence electron interactions with the GGA (PBE,PBEsol,PW91,WC) and LDA chosen for the exchange –correlations. The cubic ScF3 was modeled using 4-atoms. The calculated lattice parameters for cubic ScF3 were found to be in good agreement with previous studies and differed by -1.17% to 1.07% from the experimental value. The calculated elastic constants (C11=231.65GPa to 280.15GPa, C12=16.41GPa to 18.18GPa and C44=17.74GPa to 18.61GPa) were also in agreement with the existing cited data. This paper points out the fact that ScF3 is a ductile material at ambient conditions and will deform under tensile stress.
Compositional Analysis and Optical Properties of Co Doped TiO2 Thin fFlms Fabricated by Spray Pyrolysis Method for Dielectric and p Hotocatalytic Applications
(Urban & Fischer, 2017-01-01) Wafula, Henry B.; Musembi, Robinson J.; Juma, Albert O.; Tonoi, Patrick; Simiyu, Justus; Sakwa, Thomas W.; Prakash, Deo; Verma, K. D.
Cobalt doped TiO2 thin films (CTF) deposited by spray pyrolysis has been studied. The compositional analysis has been done using RBS method, while optical spectroscopy has been done by measuring the transmittance and reflectance of the films. The CTF thin films were prepared by doping TiO2 at different concentration levels of Co which was varied between 0 and 4.51 at.%. The optical transmittance of the thin film has been found to be about 80% in the visible and near infra red regions. The calculated optical band gap has been observed to shift by about 0.22 eV, this shows a high potential for application as a dielectric and a Photocatalyst material.