ABSTRACT The CdS and PbS are of great research interest due to their outstanding electronics and optical properties such as winder energy band gap phase and good antireflective properties respectively. CdS has been earlier doped by Zn and used as a window layer combined with PbS as the absorber material using the CBD method. It realised an efficiency of 0.9. It is for this reason in my research, I doped CdS with Se in the fabrication of CdxSe1-xS/PbS PN junction for solar cell application to...
ABSTRACT Cavitation in a centrifugal pump has a significant effect on pump performance. Cavitation degrades the performance of a pump, resulting in a fluctuating flow rate and discharge pressure, that reduces pumps efficiency and the operating life of the pump, In this research the effects of cavitation on pump performance was studied on the power required ,efficiency , volume flow rate ,and the head , using a 3-D simulation by ANSYS (fluent flow) software for two phase flow (the water and i...
ABSTRACT Forced convection grain dryers are more efficient and achieve greater drying rates than natural convection dryers. However, it is necessary to provide an appropriate solar air heater in order to achieve the required drying air temperature. Well sized fan and drying cabinet, as well as an optimal combination of air velocity, temperature and grain layer thickness are also essential for improved performance of such a dryer. In order to predict variation of moisture content with time dur...
ABSTRACT Biomass energy in the form of woodfuel and charcoal contributes close to 68% of the total energy demand in Kenya. The continued depletion of biomass resources has led to the use of agricultural residue to supplement energy needs for domestic cooking. Biomass stoves used to burn these fuels in Kenya are characterized by high inefficiencies and high emissions that pose environmental and health risks to the users. This research aimed to reduce biomass fuels consumption, reduce fuel indo...
ABSTRACT The rapid population growth in Kenya and the world in general has led to very high energy demands; this has necessitated urgent exploration of other alternative energy sources. Solar energy is one such alternative that has not been fully utilised hence many researchers have developed much interest in them. Solar cells absorb light from the sun and convert it in to useful electrical energy however the challenge has been how to harness it as well as the very low efficiencies recorded b...
ABSTRACT Solar photovoltaic (PV) energy has been widely used for decades especially where connection to a national grid is seldom possible and other sources such as fossil fuel and others are either unavailable or uneconomical. Solar PV energy owing to its free, natural availability and environmental friendliness has found demand for use in industries, homes and institutions. However, very little research has been carried out to precisely establish its effectiveness, reliability and adequacy....
ABSTRACT Communication systems require development of low cost, low profile and minimal weight. Microstrip antennas (MSA) are capable of maintaining high performance over a wide spectrum. Technological trends have focused much effort on the design of the microstrip patch antennas. In this study, square, circular and rectangular patches were designed and analyzed using two different substrates. High Frequency Structure Simulator (HFSS) software was used to simulate, model and analyze the MSAs....
ABSTRACT Microstrip patch antenna(MSA) has become very vital in communication system due to its attractive features such as its light weight, small size, low cost, low profile, ease of installation and its conformability to planar and non planar surfaces, when a particular mode and shape is selected. MSA are versatile in terms of resonant frequency, impedance, polarization and electromagnetic wave pattern. However, MSA have been found to suffer from relatively narrow bandwidths. The consumers...
ABSTRACT Students’ performance in Kenya Certificate of Secondary Education (KCSE) mathematics in secondary schools has been poor for many years in Kenya, particularly in Tana River County. Despite the various attempts by the Ministry of Education to put in place measures such as in-servicing mathematics teachers through Strengthening of Mathematics and Sciences in Secondary Education (SMASSE) project, review of the syllabus and subsidizing fees for the students, the KCSE mathematics mean s...
ABSTRACT Climate uncertainties pose a challenge to the production of food to feed the growing billions on the globe. Climatic conditions can change abruptly ruining farming efforts and leading to food shortages. Greenhouses attempt to solve this problem by enclosing crops in a climatically controlled environment. Crop production in greenhouse environment has the advantage of obtaining reliable and continuous output throughout the year. Each greenhouse has distinct characteristics. Data on the...
ABSTRACT Graffiti takes the form of written language whose authorship always remains anonymous. It precisely refers to any wall writing, pictures and symbols or markings of any kind on any surface anywhere no matter what motivates the writer. Most graffiti are viewed as illegal or vandalism of property by those in authority. Secondary school students use graffiti as a form of communication when they feel other channels to express themselves, have been blocked by those in authority. This study...
ABSTRACT Micro hydropower generated electricity can function as an effective tool for rural development. One of the barriers to smooth implementation of community/village micro hydropower schemes in the country is lack of appropriate hydraulic turbines, thus making the site specific costs of micro hydropower rather high, hence not easily affordable by the rural communities. The purpose of the study was to investigate the use of a vehicle live axle-propeller shaft system to replace conventiona...
ABSTRACT Greenhouse technology should be embraced as a way of minimizing food insecurity in Kenya. The insecurity is brought about by climate uncertainties. Greenhouses have attempted to solve this problem by enclosing crops in a climatically controlled environment. Each greenhouse has distinct parameters. Data on these parameters need to be collected at regular intervals. Depending on the type of crop, these parameters need to be controlled within the specified limits to achieve the maximum...
ABSTRACT Environmental pollution caused by the Municipal Solid Waste (MSW) incinerators has raised concerns about the quality of incinerators and the incineration process in Tanzania. Engineers and Scientists in general have appreciated that the installation of functional incinerators will increase the incineration process efficiency. Among the methods to achieve this is the application of mathematical modeling for the incineration process. Literatures have showed that related study in i...
ABSTRACT Audio noise monitoring and control has been a subject of research for several decades. Researchers have developed audio noise monitoring systems which rely on computers, internet and mobile telephone services which are costly and bulky and whose output is not easy to associate with any medical or psychological effects of noise. Active noise control has been explored using digital signal processors and field programmable gate arrays which are more costly than microcontrollers. Complex...