http://hdl.handle.net/20.500.12283/358 Fri, 03 Apr 2026 21:29:18 GMT 2026-04-03T21:29:18Z http://hdl.handle.net/20.500.12283/4402 Weighted Mean Temperature Models for Estimating Global Navigation satellite system precipitable water vapor over East Africa Peter Mbayo The weighted mean temperature ( Tm ) is an important parameter in deriving accurate and reliable Global Navigation Satellite System (GNSS) Precipitable Water Vapor (PWV) values especially in tropical regions. However, the accuracy of GNSS - PWV in the East African region is limited by the availability of precise and reliable meteorological data for computing accurate Tm values. To address this limitation, this study developed site-specific and regional Tm models for East Africa (E.A) using radiosonde and Ozonesonde profiles from 1971 to 2019. The models were validated using radiosonde profiles from two stations 63741 (Dagoretti) and 63894 (Dares-salaam) based on Root Mean Square Error (RMSE) and Mean Bias Error (MBE) values of Tm . The Tm values from the established models were compared with the two global (Bevis and Yao) and one Tropical regional (Raju) Tm models in order to assess their performance. At station 63741, the RMSE of the E.A model, the site-specific Tm model, the Bevis, Yao, and Raju Tm models are 2.01 K, 1.76 K, 1.79 K, 2.54 K, 2.74 K, and 2.47 K, respectively. At station 63894, the RMSE of the E.A model, the site-specific Tm model, the Bevis, Yao, and Raju Tm models are 1.66 K, 1.63 K, 1.70 K, 2.52 K and 2.64 K, respectively. At both stations, the site-specific Tm models have higher accuracy followed by the E.A model as compared to Raju Tm model and the two global Tm models (Bevis and Yao). The study further evaluated the accuracy of Tm models in the retrieval of PWV by computing PWV values at three GNSS sites (ARSH, DODM, and RCMN). The GNSS - PWV values computed from different Tm models were compared with PWV values derived using Tm from ERA5 reanalysis dataset from 2013 to 2020. The use of GNSS-PWV from ERA5-Tm as the reference values was due to the limited Tm values from Radiosonde during the same periods of available GNSS data required for PWV estimation. In terms of RMSpwv, the site-specific models exhibit values ranging from 0.107 mm to 0.11 mm, with a mean value of 0.109 mm, which is the lowest among the five models. This is followed by, the E.A regional model with mean value of 0.127 mm, Yao Tm with a mean value of 0.129 mm, Bevis with a mean value of 0.130 mm, and Raju with a mean value of 0.148 mm.The results show that the E.A regional Tm model and site-specific models perform better than the global and other tropical regional Tm models. Therefore, the established Tm models are the preferred choices for estimating Tm for GNSS - PWV retrieval in the East African region. Overall, the study provides improved Tm models for accurate estimation of GNSS - PWV in the East African region, which could improve weather and climate forecasts. The ward of master of Science in physics of Busitema University Wed, 06 Mar 2024 00:00:00 GMT http://hdl.handle.net/20.500.12283/4402 2024-03-06T00:00:00Z http://hdl.handle.net/20.500.12283/3910 Effects of impurities on the heat absorption and retention capacity of freshwater: Opolot, Timothy The effect of impurities on the heat retention and absorption of freshwater was investigated with a view on identifying which impurity gave freshwater the best heat retention and absorption ability. The effect of concentrations of impurities on the heat absorption and retention capacity of water was also investigated. Two methods were used each for the determination of both heat retention and absorption of freshwater. Measured values (10g, 20g and 30g) of sugar samples was dissolved in a 100ml polypropylene beaker of water and kept in a freezer simultaneously till the solutions attained freezing point, with the temperature drop recorded at intervals of fifteen minutes with a digital thermometer. The beakers were removed simultaneously from the freezer with the temperature rise recorded till room temperature was attained. Measured values (10g, 20g and 30g) of sugar were each added to 100ml of water, and the solution heated to boiling point. This was done for samples of Salt. Time taken for each sample to reach boiling point was also recorded. A cooling system was setup with the aid of a copper calorimeter and stirrer, to enable uniform temperature during the cooling process. A digital thermometer was used to record temperature drop at each fifteen-minute interval till room temperature was attained. Graph of temperature against time was plotted using Microsoft Excel Spreadsheet, in which the rate of heat retention and absorption of impurity solutions and freshwater was determined. The results showed that salt water has the highest capacity to retain and absorb more heat than sugar water and fresh water respectively, and generally the concentration of impurities in solution also determines the rate of heat retention and absorption ability. Dissertation Sun, 01 Jan 2023 00:00:00 GMT http://hdl.handle.net/20.500.12283/3910 2023-01-01T00:00:00Z http://hdl.handle.net/20.500.12283/3905 The design and construction of simple home inverter Okal, Peter As a result of lack of reliable and affordable power in villages, sensitive appliances are not in use since most of them uses A.C power supply Then, this project is to provide affordable and reliable power supply of to power home with enough light, power for charging phone, use other appliances which uses A.C power which is not available in rural areas. Dissertation Sun, 01 Jan 2023 00:00:00 GMT http://hdl.handle.net/20.500.12283/3905 2023-01-01T00:00:00Z http://hdl.handle.net/20.500.12283/3901 Incorporation of a water level indicator in the design and construction of septic tanks Odema, Robert Moris Septic tank blockages and overflows have always been a common problem. Mitigation of this problem would require an automatic sensing mechanism which would always help to alert people early in advance. This project was therefore intended to incorporate a water level indicator in these systems to curb the above problem. A circuit was designed and its sensors installed at different depths of the septic tank such that when the level of wastes rose and reached these preset levels, different warning lights glowed and a buzzer sounded at the last level. This therefore gave early warnings so that the manholes of the septic tank could not burst open to ooze out foul wastes which would disrupt normal activities of man. This project is geared towards improving hygiene in private homes, residential facilities and public places of convenience where septic tanks not connected to sewage lines are used. Dissertation Sun, 01 Jan 2023 00:00:00 GMT http://hdl.handle.net/20.500.12283/3901 2023-01-01T00:00:00Z