MST-School of Engineering and Technology

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This collections contains bibliographic information and abstracts of Master theses and dissertation in the School of Engineering and Technology held in Kenyatta University Library

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Utilization of energy saving Cookstove Technology: The case of improved institutional cookstoves in Kisii and Nyamira Districts of Kenya
(Kenyatta University, 1999) Mosomi, Evans Nyamweya; Laichena, Justus K.
The main objective of this study was to determine the factors that influence the adoption and utilization of improved institutional cookstoves, which have a higher thermal efficiency, are safer to use, and are more user-friendly than the traditional cookstoves. Evaluation of the utilization, operation, and maintenance of the improved cookstoves, by those using them, was another major objective of the study. The study was carried out in institutions that offer catering services in Kisii and Nyamira Districts of Kenya. These included schools, colleges, hospitals and hotels. The study area falls under the highly populated regions of the country, where the shortage of fuelwood is currently acute. Institutions used in the study were randomly selected and constituted 61% all of the institutions offering catering services in the study area. These included 53 schools, 4 colleges, 10 hospitals, 10 hotels and restaurants. Three manufacturers-cum-disseminators of improved institutional cookstoves were also interviewed, two of which were based in Nairobi and one in the study area. The study was conducted by use of questionnaire and interview method. By use of three different sets of questionnaires, responses from the interviewee and observations by the interviewer were recorded. The first set of questionnaires was for cateresses and/or administrators of the study institutions, the second for kitchen staff, and the third for the cookstove manufacturers-cum-disseminators. Only 57% of the sample institutions were found to have adopted and were using the improved cookstoves. This is rather low considering the acute shortage of fuelwood in the study area, hence the need for use of energy-saving devices. The study established the main factors causing hindrance to the adoption of institutional improved cookstoves as the lack of awareness, among the non-users, on the existence and advantages of the improved cookstoves and the lack of information on where to acquire them. A reasonable number of the non-users knew about the improved cookstoves, had interest of acquiring them, but did not know where to buy them from. The initial cost of the improved cookstove was also reported as a limiting factor, though not rated very high. Reduction in the fuelwood used for a given cooking activity was generally acknowledged as being attainable with usage of the improved cookstoves. Such fuelwood saving translated directly to monetary gain through reduced expenditure on the cost of purchasing fuelwood. The study also found that the most desired characteristics of the improved cookstoves, by the kitchen staff, are that they provide a smoke-free and cool kitchen environment, are safer to work with, cook faster and keep the food hot for a long period after cooking. They however did not like their lack of tilting mechanism. In spite of the numerous advantages cited, the study showed that there were some users of the same cookstoves who did not realise their advantages. This was due to misuse of the cookstove through improper operation, poor preparation of fuelwood, poor or no maintenance of the cookstove system, and failure to repair or replace broken or damaged parts of the cookstove. This was mainly due to lack of training on the operation, repair, and maintenance of the improved cookstoves. Manufacturers-cum-disseminators of improved cookstoves by conceded that they had not marketed the cookstoves widely. This was actually the cause of the lack of awareness to potential buyers. There is, therefore, a clear need for better promotion strategies by the disseminators of the improved cookstoves since there is an existing large market.
Modern technology adoption trends of small and medium electrical/electronics manufacturing enterprises registered in Nairobi
(2011-12-01) Magu, David M.
Growth in the manufacturing sector is widely considered a great vehicle for economic development, a fact taken up by Kenyan policy makers by setting a policy of ensuring industrialization by the year 2020. However, as evidenced by the case of newly developed countries, meaningful industrial development is preceded by technological advancement. In Kenya, performance of the manufacturing sector has been on a decline in the last decade. This has been attributed to lack of adequate technical and entrepreneurial skills coupled with inadequate research and development, which constrained technological advancement. In the Electric and Electronic sub-sector, most of the enterprises have engaged in production of traditional electrical products such as electric cables, lamps, electrodes and fans. Only a few have been involved in the manufacture of the more modern and high growth potential products such as computation, automation and communication equipment. Yet, studies in more successful economies, such as USA and South Korea, have shown manufacture of modern and dynamic electric and electronic products to be the growth vessel in the subsector. This study focused on modern technology adoption efforts by the Small and Medium Electrical and Electronics Manufacturing Enterprises (SMEEMEs) in Nairobi. The main objective was to find out how the SMEEMEs in Nairobi, and by extension, Kenya, can build up their technological capabilities which would in turn raise their product quality, productivity, product variety and engage in production of the modern high growth potential products. The study was carried out between May and December 2004, in Nairobi industrial area, Parklands and Baba Dogo road, among fourteen electric and electronic manufacturers that employed between 10 and 249 workers. The researcher, through face-to-face interviews, conducted data, collection with the entrepreneurs, using interview guides. Descriptive statistics were used for data analysis and presentations. All the SMEEMEs were found to be engaged in the manufacture of the earlier generation products, except 14% who were also manufacturing the modern generation products. Though some firms in the manufacture of the earlier generation products were equally doing well as those in both the earlier and the modern generation, it came out clearly that those firms that were encroaching on modern technology practices as indicated in the status of their machinery, their new products, their product development methods and their skills upgrading approaches, were thriving and had high plans and hopes for future growth. However, 43% of SMEEMEs showed little or no tendency towards improved technological activity and were just coping and others struggling in the globalized market where `survival for the fittest' bluntly applies. Of the constraints facing the SMEEMEs, competition from imports was cited as the number one most severe constraint by 8_5.7% of the SMEEMEs, while lack of adequate financial resources was ranked second by a similar. percentage. Poor utilities were ranked third by 71.43% of the firms. However, 14% of the SMEEMEs that were more technologically advanced highlighted the problems of lack of markets for the high technology products and lack of trained manpower. Taking the sub-sector as a whole, the study found out that the technology upgrading methods that had spurred tremendous growth in the sub-sector in the newly developed countries, such as joint ventures, foreign direct investment and hire of technical licenses/contracts, were hardly exploited. Most of the firms emphasized on research and development, and acquisition of hardware for their new technology requirements, which were in turn limited by the constraints mentioned above. Recommendations from the study were that, first, further improvement of the enabling environment be done, especially through macro-economic interventions, and establishment of more deliberate technology upgrading initiatives such as a national technology foresight programme and establishment of technology parks. Secondly, individual firm initiatives are required to take advantage of the enabling environment and following conventional best manufacturing practices such as new product development and agility.
Design of a solar tracking concentrator system for process heat generation
(2011-12-07) Githuku, Simon Mwangi
In Kenya, biomass energy accounts for 75% of the energy consumed for domestic heating and industrial process applications. This has lead to massive deforestation and environmental degradation. In seeking solutions, this project was undertaken to develop a solar concentrating system for process heat generation in Kenya. The goal of the study was to design, construct and evaluate the thermal performance of the solar tracking concentrator for process heat generation. The solar tracking concentrator was designed, constructed and tested under field conditions in Kenya from February to August 2004. About 70 trials were conducted to investigate its thermal performance. The system components included rotating support structure, tracking unit with cylinders loaded with evaporative solvents, collector assembly (parabolic concentrator and receiver) and heat recovery unit. Locally available materials (including shock absorbers, solvents, square metal tubes & plywood) were used to construct the system. The measured parameters included solar radiation, ambient temperature, wind speed, tracking cylinders temperatures, water inlet and outlet temperatures, water flow, air inlet and outlet temperatures, airflow and tracking angle. The tracking unit utilized solvents for its operation. Three types of solvents used included chloroform, carbon tetrachloride and methylated spirit. The tracking angle was read and recorded manually at a regular interval of 10 minutes. Average process temperature ranging between 41.8 ± 9.7°Cand 59.3 ± 147.7°C was generated with an average insolation of 665 ± 302.1 W/m2 and 684.4 ±147.7 W/m2 for the non-tracking and the solar tracking systems respectively. From 70 field tests conducted in Kenya with system loaded with methylated spirit, chloroform and carbon tetrachloride the following was concluded: (a) Chloroform solvent with an average tracking accuracy of 82+13.2% proved to be better than that of carbon tetrachloride that had tracking accuracy of 74.1± 2.5%. (b) The use of mirrors on the solar concentrator's surface and integration of a solar tracking system increased the thermal efficiency by an average of 9.0 ± 1.5%. (c) Concentrating system loaded with chloroform showed potential to generate 82.5± 5kWh per day when operating with averaged solar radiation of 644.3 ± 30.5 kW/m2. (d) The solar tracking concentrator loaded with chloroform solvent demonstrated great potential for use in process heat generation, industrial and agricultural drying operations in sunny countries.
Performance of a 2-element plane reflector augmented flat plate collectors for solar water pasteurisation
(2011-12-07) Ako, Elias Onyango
Access to safe and adequate water supply and improved sanitation is a fundamental need and a basic human right vital for health and dignity of all people. The situation has therefore called for concerted effort which has been expressed in the global commitments reiterated in the Millennium Development Goal (MDG), to reduce to half the population of people who lack access to safe and adequate water supply by 2015 and provide safe and adequate water for all by the year 2025. There are various techniques that have been used ,to disinfect water and make it safe to drink. These include: chlorination, ultra-violet disinfection, use of ozone gas, pasteurization and mixed-oxidant gaseous systems which is the most recent technology. Conventional water treatment methods rely heavily on chemicals, high energy consumption, use of expensive equipments and huge capital investments. Although they are suitable where large amount of water is required, they are not suitable for most rural settings existing in Kenya today that are normally scattered making centralized system a very expensive venture. Direct application of heat is one of the oldest and most reliable method of water disinfection. This study has pursued the concept of heating water using solar thermal energy to kill disease causing organisms, mainly E. coli which is one of the major indicator of fecal pollution in water. The direct heating of water was investigated using a 2m2 flat plate collector with a 2- element plane mirror reflector used to concentrate solar radiation from an aperture area of 4m2. Two experimental collectors were investigated; one having 20mm diameter galvanized pipe with a 26 gauge stainless steel absorber sheet and the other with 18mm diameter copper pipe with a 32 gauge aluminum absorber sheet. In both investigations, collector without reflectors was used as control experiment. Thermal performance tests have been conducted using continuous flow operation at controlled flow-rate (30±31/hr and 40±31/hr) and using pasteurization tests with thermostatic valve installed with a valve opening temperature of 82°C. In both the experimental systems under investigation it was observed that the use of mirror increased the day average instantaneous efficiency by up to 10% during continuous flow operation and up to 100% in output of pasteurized water discharged via the thermostatic valve. Water quality tests were done for both raw and pasteurized water samples using presumptive test for total coliform and Eijkman test for confirmation of E. coli in water. There was no E. coli found in pasteurized water. Data analysis was done using both descriptive and inferential statistic. An economic analysis of the solar pasteurization system has indicated an annual saving of up to 5tonnes of wood for collector with reflectors and an aperture area of 4m2 having a daily pasteurization output of up to 1001iters for a day under clear sky condition with an average solar radiation of 720W/m2, ambient temperature of 28°C and average wind speed less than 2m/s. Thus, the adoption of this study would not only reduce the number of uses of water borne diseases such as cholera and typhoid which have been identified as major cause of morbidity in Kenya by the Health Sub-sector Strategic Plan (19992004) but also lead to a reduction in environmental degradation, green-house gas emissions and health effects associated with inhaling smoke.
Performance of a photovoltaic module with an integrated compound parabolic concentrator and a cooling system
(2012-01-19) Tanui, Jeremiah Kiplagat
In recent years, Photovoltaic (PV) power generation has been receiving considerable attention as one of the promising energy alternatives for rural areas in developing countries. However, their widespread adoption has been hampered by the high capital cost and low conversion efficiencies of the available systems. Incorporation of a solar concentrator has been found by a number of researchers to increase the electrical power output of a PV module. However it exceedingly raises the module temperature, consequently lowering further its conversion efficiency. The study was carried out to improve the conversion efficiency of an amorphus silicon PV module and to reduce the cost per unit output of the energy generated. This was done by incorporating a Cooling Unit (CU) and a Compound Parabolic Concentrator (CPC) to the PV module, forming a Combined Heat and Power (CHP) system generating electricity and hot water. By circulating a fluid with a lower inlet temperature at the back surface of a PV module, heat is extracted from the PV module, thus maintaining the module cell temperatures at a lower level. This improves the electrical conversion efficiency of the cells. The extracted heat can be directed into useful purposes. This forms a Combined Heat and Power (CHP) PV system. Use of low cost concentrators on a CHP system increases the radiant energy available per unit surface of the module resulting in lower cost per unit of energy generated. Four experimental system were investigated: (i) Plain PV module (ii) PV module with cooling unit (PV/CU) (iii) PV module with a CPC (PV/CPC) and (iv) PV module with a CPC and a Cooling Unit (PV/CPC+CU). Water was used as the cooling agent at a controlled flow rate. Three flow rates of 20 l/hr and 40 l/hr were tested in the study. Data collected were: current, voltage, solar radiation, ambient temperature, module temperature, and the inlet and outlet cooling water temperatures. A data logger (model Fluke 2286 series, U.K) was used to record data continuously at regular intervals from 9.00AM to 5.00PM. The power output, electrical and thermal efficiencies for the various study modules were computed and compared. Financial evaluation was performed by comparing the Levelized Energy Cost (LEC) of the systems tested. The results obtained indicated that the cooling of a 51Wp PV module increases its electrical conversion efficiency. The PV module was cooled by an average of 14°C from 48.5°C to 34.4°C, which increased the electrical power output and efficiency by 45.6% and 37.5% respectively. Combined CPC and cooling showed better electrical performance on the PV system than either the CPC or cooling alone. In total, an integrated CPC/CU had the best performance at a colling water flow rate of 40 l/hr, which increased the electrical power output and efficiency by 118.74% and 120.0% respectively in comparison to PV Plain. The 25% truncated CPC also increased the thermal energy output of the combined heat and Power (CHP) PV system. The maximum thermal energy output was observed at a cooling water flow rate of 30 l/hr. At this point the thermal energy output was 3.018 KWh/day. This study has shown that a CHP-PV system with added CPC increased the electrical power output of conventional PV modules with the benefit of generating useful heat energy in the process. These findings are important contributions in the research efforts aimed at increasing the acceptability and affordability of solar technology in the rural areas of developing countries.
Potential of using maize stalks for fuel ethanol production.
(2012-02) Mwangi, Lucy K.
In Kenya, a country that has not been successful in getting its own fossil fuel deposits, the main material used for ethanol production has been molasses but its supply compared to demand is becoming limited. There is need for alternative materials to produce ethanol without affecting food supply. This study investigated the potential of juice from maize stalks grown locally and normally a byproduct of maize farming, for production of fuel ethanol. Selected Kenyan maize varieties were grown in two seasons, March and September of year 2008. This was done under typical field conditions and sampled at three growth stages, the silking, the milk stage and dry maize stage. Maize varieties for three agroecological zones in Kenya were used, the low dry lands, the medium altitude and the highlands varieties. The juice was extracted by crushing the stalks with a 3- roller mill sugarcane crusher and analyzed for total sugars using a digital refractometer (NR-151, China) and specific sugars using a high performance liquid chromatography (HPLC) with a reverse phase column and refractive index detector (RID). The juice was then fermented using baker's yeast (Saccharomyces cerevisiae) at constant temperature of 27DC and a pH range of 4-5, distilled at 78 DC and the yield of alcohol determined. The ethanol obtained was tested in a Chinese wick stove (wheel brand model 62) for fuel properties (specific fuel consumption, fire power, burning rate and thermal efficiency) for domestic cooking application. Its performance was compared to that of kerosene fuel. The highest juice yield obtained was 176.67mllstalk (18840litres/hectare) for maize variety HB625 at the green maize stage, while the lowest was 8.33ml/stalk (616Iitres/hectare) for variety Katumani in the dry maize stage. The two varieties also had the highest and lowest ethanol yields at 1445.5litres/hectare and 42litres/hectare respectively. Hybrids had the highest juice and ethanol yields per hectare. The three main sugars identified in the maize stalk juice were sucrose, glucose and fructose. The trend for the sugars was a decrease for fructose and glucose and an increase in sucrose as the maize plant matured. Ethanol obtained burnt with a blue flame compared to the yellow flame of kerosene, with a power output of 1.08kW and a thermal efficiency of 38.2%. However, about 2 times the quantity of fuel and heating time was required for ethanol compared to kerosene to bring to boiling point the same amount of water at the same conditions. The average cost of producing llitre of ethanol (93%v/v) from the maize stalks was found to be KSh.63.56 (about 1USD). The study has contributed positively to the search for a clean sustainable energy resource and consequently reduction of dependence on the fossil petroleum fuels in Kenya and other countries. Use of maize stalks as feedstock for ethanol production gives a renewable source of energy for the motor industry and for domestic cooking. Maize grows in plenty in Kenya and this can boost energy security for the country and also contribute to economic growth for the country, specifically the rural economy through diversification of the agro-industry.
Performance of a modified vehicle drive system in generating hydropower
(2012-04-03) Muriithi, James Muchira
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 axlepropeller shaft system to replace conventional turbines for micro hydropower generation. There are axle-propeller shafts of many vehicles that have fallen into disuse and are commonly found in many motor vehicle scrap yards. New ones are also entering the Kenyan market with the small vehicles (saloon cars; station wagons; panel Vans, Pick-ups, lorries/trucks, buses/coaches and minibuses/matatus) comprising the biggest percentage, for example in the year 2008, out of 121,831 newly registered vehicles 65,556 (53.8%) belongs to this category. The study was carried out mainly to investigate and establish the performance of the live rear vehicle axle-propeller shaft as a micro hydropower electricity generation system with the objective of lowering the unit cost of hydropower generation in small water streams. This was done by modifying a vehicle axle propeller shaft system by fixing designed buckets on the wheel rim to take the role of a turbine runner and replacing the propeller shaft right from the rear universal joint with a solid bright steel shaft where mechanical power is generated and tapped. A wheel rim/turbine casing with a nozzle for creating a water jet was fabricated and together with a mounting frame for the axle formed a complete Vehicle Propeller-Axle as a Turbine (PAA T). A jet of water from the nozzle strikes the buckets and the kinetic energy is converted into rotating shaft power by the wheel rim and the rear axle. The power is transmitted through the differential box with an accompanying speed increase to the rear universal joint where a shaft is fixed for eventual mechanical power take off. The power can be used to drive mechanical equipments or an alternator to generate electricity. The performance of the propeller-Axle as a turbine was tested at a community hydropower site in Kirinyaga, constructed for this purpose. The tests were conducted to determine the power output and efficiency under a constant head and different discharges. The final result of the study was a low cost vehicle axle-propeller shaft system operating as a turbine cost of USD 274.4), generating 1.18 kW of shaft power at an optimum flow rate ofO.0238 m /s at a gross head of 21.874 m and at an optimum loaded runner speed of 500 rpm. The specific speed of the modified vehicle system as a hydraulic turbine was 12. The energy cost from a hydropower scheme using a vehicle axle-propeller shaft as a turbine is 10 times cheaper than that of a similar scheme using a diesel generator as its source of power. These research findings are an important contribution to providing a solution to increasing use of micro hydropower for rural electrification by making the technology available and affordable to individual and communities in the rural areas. Vehicle drive systems are available as dumped materials in most metal scrap yards and car garages scattered across the country and they are an environmental hazard as there are no vehicle parts re-cycling facilities in the country.
Determinants of Soil Water Conservation and Nutrient Flow Management in Bufundi Sub-Catchment.Kabale District,Uganda
(2013-03-20) Kaliisa, Robert
Soilerosion and declining soil productivity still continue to manifest in most of the agricultural systemsfound in Sub-Sahara Africa and this has threatened the agricultural productivity, biodiversity,water quality and availability as well as the livelihoods of the poor who depend on land.In Uganda, this has been attributed to poor land use practices with inadequate SWC measuresand persistent nutrient mining of the soils with little or no replenishment. Highland areasofKabale are reported to be severely affected by soil erosion and declining soil fertility despitecontinued efforts by farmers to conserve soil and water resources. The study examined thedeterminants for SWC and nutrient flow management in Bufundi sub-catchment. The study waspremised on analyzing physical, institutional and social economic factors as they were perceivedto stronglyinfluence'SwC and nutrient flows within the different farm slope positions ofBufundi sub-catchment. Ni~ety five (9S) structured questionnaires, key informant interviews andtransects were conducted in the month of January 2011. Also 30 soil samples were collected fromagricultural fields on the predominant SWC measures (terrace benches) in addition to nutrientmonitoring using the NUTMON questionnaires, transfer functions and a NUTMON monitoringguide. Data analysis was done using SPSS 17.0, E-view 3.0 and NUTMON 3.6 softwarefor the different types of data. The results of the survey show that family size, age, land , . tenure,perception of soil erosion, sources of income, formation of Innovation Platforms (IPs), farmsize, collective marketing under IP, slope, collective action and training in SWC are among themajor factors that positively and significantly influence adoption and use of soil and water conservationmeasures. Education, sex, off-farm activities, visits by extension agent, showed no significantinfluence on adoption and use of soil and water conservation measures. Soil data in thepredominant SWC measures (terrace benches) revealed that: pH, organic matter, and nitrogen werebelow the critical values on all the"t~rrace farms. It was revealed that organic manure (IN2) wassignificant at (p
Calcium Chloride Supported on Purified Spent Bleaching Earth as Potential Adsorptive Material for Air Dehumidification Application
(2013-03-22) Mathaga, Kihara John
Thecosmic limitation of high humid environment in tropic regions spurs a lot of interest to the developmentof low cost desiccants. Calcium chloride has been indicated as the oldest adsorbent desiccant among chemicals and gas dehydration industries. However, calcium chloride dissolution behaviour makes it difficult to be utilized well as desiccant. The first attempt to suppressdeliquescence behavior for dehumidification purpose was in 1976 where silt loam was usedas the host material. Further work has been presented to achieve the same goal using pure clay.The pollution effect of the spent bleaching earth (SBE) necessitated an investigation to determinewhether SHE could be used to eradicate the deliquescence behaviour of calcium chloride.The spent bleaching earth was purified to remove the entrained hydrocarbons through three steps; solvent extraction using hexane, oxidation of the hexane residues using 30% hydrogenperoxide and thermal oxidation. The ratio of 1 gram spent bleaching earth to 5 ml hexane and reactivation temperature of 550 DC in thermal oxidation were established as the optimalconditions for reactivation of spent bleaching earth. Hexane was found to remove about 25% of the entrained hydrocarbons mainly oil which was characterized. The results for the characterization indicated that the oil recovered could be utilized in non-food applications such as bio-lubricant, detergents, soap and other oleochemicals. Hydrogen peroxide removed about 10%of the remaining hydrocarbons after hexane extraction and thermal treatment about 5% after the two preceding steps. Laboratory studies were conducted to assess the mixing ratio of the inorganic salt, auxiliary binder and purified spent bleaching earth in the development of the composite adsorbent. Samples with different ratios were subjected to a humid environment of 88%relative humidity, by preparing a saturated solution of potassium chromate in a sealed beaker.The samples which recorded.minirnum surface wetting, spalling and cracking as well as high water uptake were further subjected to multiple sorption cycle tests. For all the tests performed, sample ratio of 3 :1 :0.25 of PSBE :CaCb :starch recorded the best results and was furthertested for its sorption properties at different relative humidity's. Sorption properties were carried out in a humidity chamber at 11.3, 32.78, 43.16, 52.89, 75.5 and 93.58% relative humidity where the sorption capacity recorded 14.88, 17.60, 20.95, 24.40, 33.40 and 45.55% water uptake respectively. The desiccant developed was found to be effective in high moisture content and thus viable in tropic regions where such environs are common. The sorption data obtained were subjected to the Langmuir, Freundlich and Brunaeur-Emmett- Teller (BET) adsorption models in order to determine the type of adsorption isotherm that best interpreted . water sorption by the material. Results indicated that, water adsorption onto adsorbent developed followed BET and Langmuir type III isotherm which indicated the formation of multilayer. The sorption capacity of the adsorbent matrix developed recorded 40 to 45% water uptake which cohered with commercially available desiccant such as silica gel. Since the SBE is normally disposed on potential land and limitations for this method of disposal is enormous, it is recommended that, oil manufacturing industries should emphasis on regenerating and re-using this waste in making products such as desiccants which they can use to preserve their products as well as sell to other consumers.
Utilization and conservation of papyrus plants for sustainable livelihoods in Kusa swamp, Lake Victoria, Kenya
(2013-03-25) Auma, Janet Atieno
Kusa swamp has been adversely affected by degradation due to increase in human and livestock population coupled with poor farming methods, overgrazing and harvesting of papyrus which endangers the livelihood of the community. This study hypothesizes that there is no significant relationship between quantities of papyrus harvested per day and change in the area covered by papyrus; papyrus bundles used per day to make mats and those used to make baskets and ropes; and opinion the community hold on conservation of the swamp and, the number of community members involved in awareness creation, planned harvesting 'of papyrus and institutional arrangements. The main objective was to assess the utilization and conservation of papyrus in Kusa Swamp. To achieve this, Geographic Information Systems (GIS) was used where Google Land Cover Facility (GLCF) was used to download aerial images of Kusa swamp between the years 1985 and 2008; and a household survey comprising 96 households of respondents in the study area was carried out. Interviews were also administered to selected key informants. The research instruments. included questionnaires, Key Informant Interviews (KII), direct observation, Focus Group Discussion (FGD). Data were analyzed using descriptive statistics. To test the hypotheses, correlation analysis was used. Remote Sensing (RS) and GIS software (Integrated Land and Water Information System (1LWIS)) was used to analyze the RS images to show the change in area covered by papyrus. The area covered by papyrus in 1985, 1988, 1995, 2000 and 2008 was 66.7 km (41%), 68.9 km2 (43%), 51.7 krn2 (32%), 41.6 km2 (26%) and 37.7 krn2 (23%) respectively. Papyrus utilization is dominated by females (53.1%) and it is high among those with low or no educational attainment (80.2%). Papyrus utilization has resulted in papyrus habitat decline where the overall loss in area covered by papyrus between 1985 and 2008 was 43%, but a larger area was lost between 1988 and 2000 (37%). This trend shows that 86% of the area might be lost by 2031. It has also resulted in reduction in papyrus availability (67%), migration (75%) and death (22.9%) of animals; and change in fish diversity (36.5%). Majority (70%) of the respondents use papyrus for mat making while 30% use it for basket weaving, thatching houses, chair making, partitioning houses and ceiling. Baskets and ropes are widely used in the area. About 79% are in favour of swamp conservation while only 4.2% are currently involved in conservation activities. Initially, the community used institutional arrangements (21%), planned harvesting (31%) and awareness creation (48%) as conservation measures but they were discouraged due to lack of internal and external support. The riparian communities proposed new measures to be implemented for sustainability of the ecosystem. Kusa community continues to depend on the swamp for their livelihoods which include papyrus harvesting, farming, grazing and water. To meet these benefits against increasing population and poverty, there is need for a management strategy that accounts for both peoples' livelihoods balanced with conservation initiatives. This calls for consideration of alternative sustainable livelihood and development options by stakeholders which include recreation, research and educational sites and irrigated terrestrial agriculture where agro-forestry is practiced to help compensate for loss of papyrus. Sensitization through multi-media approach on importance of natural ecosystems will help enhance conservation efforts.
Socio-economic factors influencing household wetland resources conservation and use in Ngaciuma sub-catchment, upper Tana, Kenya.
(2013-03-26) Kithinji, Felix Muthomi
Wetland ecosystems provide a wide range of goods and services that are important in supporting the livelihood of many rural communities. Despite their importance, overexploitation and in the absence of conservation measures, wetlands continue to be degraded by human activities. Population growth pressure and .subsequent food insecurity have lead to the communities living near the wetland areas to reclaim the wetlands, thereby threatening the existence of the ecosystem. Factors responsible for wetland degradation in sub-catchments are many and varied. They include lack of understanding of the factors influencing people's access and decisions on use of wetland resources. There is minimal or no research conducted to understand the factors influencing rural household decisions on use of wetland resources in the sub-catchment. In order to understand and improve management of wetland this study sought to identify and analyse types of wetlands, assess the various households socioeconomic factors influencing wetlands resources use and conservation methods used within the Ngaciuma sub-catchment. To achieve this, a combination of key informant interviews, transect walk, observations and household survey were used to collect data. A structured questionnaire was administered to 96 households to solicit data on the households' socio-economic characteristics and wetland use patterns. SWOT analysis was used to analyze the conservations methods and sources of threats to wetland resources. A stratified random sampling technique was used to select households for interview. The data generated was coded and entered into the Statistical Package for Social Science (SPSS) and analyzed using descriptive statistics and cross tabulation to describe various patterns influencing households use of wetland resources. Correlation analysis was used to determine the relationship between the household factors and use of wetland resources. Chi square was also used to compare the relationship between the expected and the observed wetland use. The results revealed that marshes are the most common type of wetlands which are dominated by tyha species vegetation. The findings also revealed that education, income levels, household size and proximity to wetlands influence the use of wetland resources at (p< 0.05) chi-square test. The most common methods used in conservation were planting of water friendly trees and soil conservation. Major challenges of wetland conservation include insufficient information and destruction of wetlands by wild animals. The study recommends formulation of comprehensive management plans, which have legal backing, to be used to govern the use of wetlands resources. There is also need for' co-management of wetlands between the state and the communities.
Assessment of water resources utilization and management in chahi sub-catchment, Kisoro district, Uganda
(2013-07-23) Tera, Marahi Moses
There is a growing global concern over the future of the world‟s water resources due to the preceding vulnerability. Some of the factors contributing to the increase in water resources vulnerability include population growth and poor land use practices. This study assessed the local uses and management of water resources and the local coping mechanisms, identified the drivers of water resources scarcity and evaluated the opportunities and challenges of managing water resources in Chahi sub-catchment, Kisoro District, Uganda. To achieve the objectives of the study, the following empirical tools were used; a structured questionnaire, key informant interviews and field observation guides. A total of 100 households and 20 key informants were interviewed. Numerical tools for data analysis comprised descriptive statistics and non-parametric test. SWOT analysis tool was used to examine the challenges and opportunities. The study identified pipe borne water (89%), stream (58%), rain (40%) through roof catchment and vendors (8%) as the major sources of water in the sub-catchment, with domestic (100%) and agricultural (24%) being the major local uses of water. Women played a key role in the management of water sources, making use of the water and fetching of water from the water sources. Construction of water points, maintenance of available water points, fencing of the water source, participatory planning in water management, equitable distribution of water tanks and training on water management were identified by households as interventions to ensure sustainable water supply and management in the sub-catchment. Drivers of water resources scarcity in the sub-catchment included climate change (98%), poverty among the households (80%), population growth (77%), pollution (41%), inadequate information on water management (33%), land use practices (20%) and deforestation (16%). Various coping mechanisms; domestic rainwater harvesting (DRWH), water storage during plenty, water pricing, use of earthen pots, moving long distances and innovative agricultural practices were being used by the households. However, not any of all these coping mechanisms considered depicted a significant relationship with the households‟ longevity in the sub-catchment. Major challenges hindering water resources management (WRM) in the sub-catchment are; low coverage of rainwater harvesting technology at household level, lack of internal training on WRM technologies and inadequate support of water initiatives by the households. Conversely, the opportunities established include; location, support from the Central Government through the District Local Government and involvement of different stakeholders in water management. The study concludes that water shortage appears as a powerful incentive to change, eliciting major adaptations and coping strategies from users. This study recommends focus on building more water infrastructure and involvement of the households in the planning and allocation of water resources. This will contribute to improved understanding of the need for efficient water resources utilization and management on household livelihoods and also help design appropriate WRM strategies for the poor peasant farmers and provide guidance for policy makers for similar situations in Uganda and beyond.
Enhancing efficiency of biomass carbonization for high Quality and quantity charcoal production by using Metallic clay insulated kiln
(Kenyatta University, 2014) Mulei, Fredrick Mwange; Laichena, Justus K.; Okwach, Silvester
The main objective of this study was to construct a metallic clay insulated kiln to enhance charcoal yield in quality and quantity. This research project aims at improving the charcoal quality in terms of calorific value and smoke - free, and maximum yield of charcoal (per kilogram of biomass substrate loaded). The quantity of charcoal harvested per kilogram of primary four biomass materials loaded as substrates was determined in four tests in each substrate. The main objective was to develop metallic clay insulated kiln with high efficiency, economical and environmentally friendly. metallic clay insulated kiln would offer solution to the problems of low efficiencies of existing charcoal kilns, for example, Traditional Earth Mould Kiln, Mark V. Kiln, Beehive kiln, and Half Orange kiln, among others. These kilns have efficiency of 10%, 31%, 32% and 28.8%, respectively, compared to the achieved 40.85 ± 5.04 % for this metallic clay insulated kiln. In this research a metallic clay insulated kiln was constructed and tested. The major aspect is that a proto type 0.15 m' drum was used to provide feedstock housing. This was tightly covered such that no fraction of feedstock was burned to provide carbonization heat. Clay insulation housing was constructed while the drum was provided with metallic stands and each of the substrates was loaded in the drum. Insulation wall made of clay/mud was constructed to prevent heat loss from the drums and combustion area. The quantity of charcoal produced from the metallic clay insulated kiln was compared with the quantity of wood substrate used. To determine the quality of the charcoal (in terms of calorific value and smoke), universal standard charcoal testing method was used that is Water Boiling test. The quality of charcoal produced from the kiln was then compared with charcoal produced from other different existing kilns in the literature. The data analysis was done by the help of statistical package for social science (SPSS) and Microsoft Excel. In conclusion, efficiency of charcoal production should be emphasized so as to make the practice of charcoal production sustainable by use of metallic clay insulated kiln. It was also found that metallic clay insulated improved kiln had higher efficiency (40.85 ± 5.04 %) than existing kilns such as Beehive, Mark V, Half Orange, Traditional Earth Mould, drum kilns adopted by FAO and others. Adoption! utilization of the metallic clay insulated kiln (with high efficiency as obtained in this research project (40.85 ± 5.04 %)) will reduce/cut-off the problems experienced in use of the _existing low - efficiency kilns. It is both an economical benefit, and environmental friendly. Charcoal production using improved charcoal kilns with high efficiency would give much higher yields of charcoal of excellent quality (in sense of HHV and smoke-free). This can make the practice very profitable, and users will have motivation for sustainable production of charcoal.
Performance of a Double Reflector Solar Box Cooker with Phase Change Material Energy Storage
(2014-02-19) Mwaura, Margaret Muria; Thoruwa, T. F. N.; Okwach, Silvester
The use of solar energy for cooking offers an alternative source of energy to the high cost of petroleum products and the diminishing wood fuel products for cooking and heating applications. An effective solar cooker is the one that can be used throughout the day and in the evening when there is no sunshine. Most areas in Kenya can be considered as a high potential solar energy area because Kenya is located on the equator. Most of the solar cooker designs do not have thermal storage systems and can be used for cooking when there is sunshine and cannot be used during cloudy weather or in the evening. The aim of this study was to design and assess the performance of a double reflector solar box cooker with an energy storage unit. The use of phase change materials (PCMs) as a technique of storing energy was used to overcome the time mismatch between solar availability and demand. The PCM used in this study is acetanilide with a melting point ranging from 113 to 116 °C. The box cooker was designed so that the length to width ratio for the reflector and the glass window was 4:1. This eliminated the azimuth tracking towards the sun. Three sets of experiments were carried out, one without loading the cooking pot of the cooker, one with water as the cooking load and one with different actual cooking loads in the School of Engineering and Technology Demonstration Center, Kenyatta University. The measured parameters included, the solar radiation, ambient air temperature, temperatures of the different components of the solar cooker, load temperature and wind speed. The data values were read and recorded by use of a data logger at regular intervals of 10 minutes. Data analysis was done using statistical measures. An average stagnation temperature of 85.9 ± 24.0 °C and 82.7 ± 24.3 °C was achieved in the two pots. The average solar radiation was 637.1 ± 212.0 W/m2. The cooking power tests achieved a coefficient of performance of 0.754. The results showed that the double reflector solar cooker with energy storage can be used to cook meals throughout the day and in the evening. Noon cooking does not affect evening cooking. The adoption of this study will be beneficial to Kenyans as it will increase the acceptability of the solar cookers hence reduce the consumption of wood fuel and petroleum products. This will reduce the rate of depletion of wood resources, save time and reduce expenses for the user which could be diverted to increased productivity and monetary gains thus raising the living standards and a clean environment devoid of hazardous emissions associated with wood and fossil fuel combustion.
Characterization Of Snse-Cdo:Sn P-N Junction For Solar Cell Applications
(2014-08-26) Nyakundi, Makori Evans
Energy crisis occasioned by a decline in the availability of fossil fuels and increasing carbon dioxide emissions that are causing global warming has enhanced interest in the development of clean and renewable sources of energy. Solar energy has a great potential of meeting a large fraction of energy needs using photovoltaics. While most PV cells in use today are Silicon-based, cells of other semiconductor materials have been manufactured. Considerable research has been focused in search of thin-film PV cells with high conversion efficiency. In this study, SnSe and CdO:Sn thin films were optimised for photovoltaic applications. SnSe and CdO:Sn thin films were successfully deposited by thermal and reactive thermal evaporation respectively using Edward’s Auto 306 Magnetron Sputtering System . Their optical and electrical properties were studied using Solid Spec-3700 DUV Spectrophotometer and Keithley 2400 Source Meter respectively. Transmittance of the SnSe thin films deposited had transmittance ranging between 19-50% while reflectance ranged between 10-50%. The band gap values of SnSe thin films obtained were in the range of 1.71-1.76eV. SnSe thin films showed decrease of resistivity from 181-120Ωcm with increase in film thickness from 112-148nm. The optical properties of CdO:Sn showed high transparency in the visible region which varied with Sn doping, this makes CdO:Sn an excellent candidate for optoelectronic applications as a window layer. CdO and CdO:Sn had a transmittance of 70-85% and 50-89% respectively within the visible range of the electromagnetic spectrum. Reflectance of doped and undoped CdO was between 19-28%. Band gap energy for undoped CdO was 2.43eV while that of tin doped CdO ranged between 3.19-3.29eV for tin doping of 1-7%. Resistivity of CdO and CdO:Sn ranged between 16-93Ωcm. The optimised thin films were used to fabricate SnSe-CdO:Sn P-N junction. The I-V characteristics obtained were; Isc=0.993mA, Voc=273mV, Imax=0.905mA, Vmax=207mV, FF=0.69 and η = 0.59%.
Design, development and testing of a liquefied petroleum gas powered tomato dryer with water energy stotage
(Kenyatta University, 2015) Njoroge, John Kamindo
Development of Biomass Wastes Briquette Stove for Domestic Use
(Kenyatta University, 2015-11) Mulindi, Humphrey M.
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 indoor air pollution and deforestation. The project was carried out in two phases. First, in 2010 there was a survey of the status of bio-waste fuel briquetting technology in Nairobi and peri- urban Nairobi area. Secondly, a semi-gasification stove that uses briquettes derived from solid organic waste material was developed. The survey involved an interview of 63 briquette producers identified from desktop research within Nairobi and its per-urban areas, out of which 40, 15 and 8 were community based groups, NGOs and briquette producing companies respectively. A total 175 briquette users were randomly selected and interviewed from a list of briquette consumers given by briquette producers interviewed. Based on the results of the field survey, a semi- gasifier stove was designed and constructed. The semi-gasifier stove construction took place at Kenyatta University Engineering workshops. Tests were done to determine the thermal efficiency, specific fuel consumption and power of the stove. Standard stove emission test were conducted using KANE 455. About 33% of the briquettes made were from a mixture of charcoal dust and paper. Characterization of briquettes was based on their calorific value, percentage moisture, volatile matter, ash content, fragility of briquettes and burning characteristics. The calorific value of briquettes was between 14.21kJ/g and 24.64kJ/g for water hyacinth based and carbonized baggasse briquettes respectively. Moisture content of the briquettes ranged from 5.8% to 14% for carbonized baggase briquettes and for charcoal with bean stocks plus paper respectively. Carbonized coffee husks with starch binder had the lowest volatile matter of 10.1% while coffee husks with paper had the highest volatile matter of 71.2%. Briquettes made from sawdust and paper had the lowest ash content of 8.8% whereas briquettes from charcoal dust and clay had ash content of 66.8%. The percentage fragility of the briquettes sampled ranged from 0.1% to 80.4% for charcoal with clay and sawdust with paper respectively. The semi-gasifier stove had an average thermal efficiency of 30%±3 and an average fire power of 2.5kW±1.5. The emission testing of the stove using KANE 455 gas analyzer for CO, CO2 and CO/CO2 ratios showed the average values of 0.2067 ± 0.0259ppm, 2.6771 ± 0.13307ppm and 2.31374 ± 0.13184 respectively. Economic analysis show that if a family were to invest in the stove, they would save about Ksh 30($ 0.35), Ksh 1000 ($11.7) and Ksh 2200 ($25.8) ,if their initial cooking stove is open fire, kerosene stove and charcoal stove respectively. If a family claimed carbon credits by using the stove, it would be entitled to up to Ksh 8,000 ($94.1) during its entire life. For mass production the stove would retail at an average of Ksh 800 ($9.4). The prototype stove developed was found to meet the intended need for being used by fuel briquettes.
Optimization of Co-Fermentation Ratio of Water Hyacinth (Eichornia Crassipes) and Cow Dung Feedstock for Production of Biogas
(Kenyatta University, 2017) Ayub, Mjomba Samwel
Water hyacinth (WH) Eichornia crassipes, is a water weed that thrives in polluted water bodies. It has wreaked havoc in Kenyan water bodies due to its negative environmental, social and economic impacts. Despite its great potential as a source of biogas, optimization of the quantity and quality of the gas produced remains a challenge as individuals adopt do-it-yourself approach without carefully addressing the key issues that govern production. The study sought to determine the best biogas yield using cow dung (CD) as a eo-fermentation feedstock. The following proportions ofCD:WH were studied: 1:0 (no hyacinth), 1:1, 1:2, 1:3 and 1:5. Analysis of the conductivity, Total Dissolved Solids (TDS), pH, temperature, gas yields and composition were done. The experiments were conducted in a 6m3 flexible bag batch digester using different CD: WH ratios. Results showed that various ratios did not show any specific trend in electrical conductivity, however average biogas yield (in m') for ratios 1:0, 1:1, 1:2, 1:3 and 1:5 were 3.32, 6.58, 5.18, 4.1and 3.56 respectively. A similar trend was observed in the total dissolved solids (TDS).,The initial pH was between 7.0 and 7.4 while the anaerobic digestion temperature during the study ranged between 23.8-33.6 °C for all the ratios tested. The maximum biogas production rate was highest at 30.7 "C, whereas the highest gas yield were realized with ratio 1:1 while ratio I' 1:5 had the lowest yield. When the biogas was scrubbed with 15% w/v NaOH there was an increase of methane content which ranged from, 52.7% - 58.4% before scrubbing to 71.2% - 74.2% after scrubbing. The ratio of 1:1 CD:WH produced the highest volume of gas hence best eo fermentation for the ratios tested. The study has demonstrated that the potential of water hyacinth- as a biogas substrate can be enhanced by eo-fermenting with cow dung and can be utilized as a sustainable renewable energy source.
Application of mobile phone in crime prevention within Central division, Nairobi city County
(Kenyatta University, 2017-08) Wambugu, Paul M.
ABSTRACT The study sought to establish application of mobile phones applications by police officers in crime prevention in Central Police Division, Nairobi City County. Application of mobile phone in the police service is underutilized making the organization not to fully benefit from its usage. Understanding use of mobile phone applications by the police officers may assist the organization in crime prevention efforts. Due to its ability to engage consumers in a timely and direct manner at low costs, mobile phone applications are relevant for the police organization. The study was guided by the Mobile Technology Acceptance Model (M-TAM) as the success of the mobile phone implementation depends on perceived usefulness (PU) and perceived ease of use (PEOU).The targeted population in this study was police officers serving at Central Division of Nairobi County (782). A sample of 155 police officers was recruited using random stratified sampling procedure for this study. Questionnaires were used for data collection for both qualitative and quantitative data. Qualitative data was coded and analysed thematically after interpretation of theme while descriptive data was analysed using descriptive statistics by use of Statistical Package for Social Sciences (SPSS version 20.0). Mobile phone was found to be effective tool in prevention of crime in Nairobi Central. Mobile phone applications such as Facebook, Whatsapp, Twitter, emails and short text messages were found through adapted technology acceptance model (TAM) as to effectively contribute to crime prevention based on respondents’ perspective. Police effort to use mobile technology was found to have significant effects on crime prevention. Based on these findings, the study recommends development of customised police mobile phone applications and enhancement of applications use through capacity building among police officers.
Design and Fabrication of a Greenhouse Monitoring and Control System Based on Global System for Mobile Communication and Bluetooth
(Kenyatta University, 2020) Nyaga, Stephen Gitonga
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 efficiency and yields. In the past, greenhouses utilized electromechanical devices such as thermostats to monitor and control the environment. Mechanical systems lack the flexibility and precision required for greenhouse control. Some modern greenhouses use computers to control the environment. Computers based controllers are station based, bulky and costly. In this study a wireless prototype greenhouse monitoring and control system that is flexible, cheap, easy to maintain and easy to assemble was developed and implemented. The general objective of this research work was to design, fabricate and implement a microcontroller-based prototype to monitor and control greenhouse parameters using sensors, SMS technology and Bluetooth signals. The hardware consisted of ATmega328 microcontroller, Global System for Mobile communication (GSM) SIM800L module, HC05 Bluetooth module, HD44780U Liquid Crystal Display (LCD) module, 5 volt 4 channel relay module, Light dependent resistor (LDR) sensor and digital humidity and temperature (DHT11) sensor. The LDR sensor was utilized to measure light intensity while the DHT11 sensor was utilized to measure humidity and temperature levels in the prototype greenhouse. The DHT11 and LDR sensors, the relay, the LCD, the GSM and the Bluetooth modules were interfaced to the ATmega328 microcontroller. Through Arduino software, a program was written in C language, developed and uploaded to the ATmega328 microcontroller to run the greenhouse prototype. The program is designed to operate in automatic or manual mode. In automatic mode, the microcontroller constantly monitors the digitized values from the sensors and compares them with the optimized values and checks if any control procedures needs to be taken. In manual mode, the system could be operated wirelessly by use of GSM or Bluetooth module. The designed prototype greenhouse system is able to measure temperature, humidity and illuminance levels in the prototype greenhouse and display the values on the LCD. The system transmits the sensor measured values to owner’s phone via Bluetooth or a GSM and keeps these parameters at optimum levels by use of two fans, heater, bulb and a sprinkler. The GSM module is used for remotely monitoring and controlling the devices via a smart phone by sending and receiving Short Messaging Service via GSM network. If the user is in the vicinity of the prototype, the Bluetooth and a software installed in the smart phone provides a wireless link between the prototype and the cell phone. This project therefore provides a cost effective and efficient means of monitoring and controlling greenhouse parameters. In addition the system allows mobility during monitoring and control process. The reliability of the designed system can be exploited to build a network of such monitoring and control systems for several greenhouses. A website can be incorporated in the designed system to monitor the actual greenhouse values and save the data in an online database for future reference. The designed prototype greenhouse can be applied in the agricultural sector in the design and implementation of greenhouses.

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