Abstract. We report on the longitudinal, local time and seasonal occurrence of equatorial plasma bubbles (EPBs) and L band (GPS) scintillations over equatorial Africa. The measurements were made in 2010, as a first step toward establishing the climatology of ionospheric irregularities over Africa. The scintillation intensity is obtained by measuring the standard deviation of normalized GPS signal power. The EPBs are detected using an automated technique, where spectral analysis is used to extract and identify EPB events from the GPS TEC measurements.Overall, the observed seasonal climatology of the EPBs as well as GPS scintillations in equatorial Africa is adequately explained by geometric arguments, i.e., by the alignment of the solar terminator and local geomagnetic field, or STBA hypothesis (Tsunoda, 1985(Tsunoda, , 2010a. While plasma bubbles and scintillations are primarily observed during equinoctial periods, there are longitudinal differences in their seasonal occurrence statistics. The Atlantic sector has the most intense, longest lasting, and highest scintillation occurrence rate in-season. There is also a pronounced increase in the EPB occurrence rate during the June solstice moving west to east. In Africa, the seasonal occurrence shifts towards boreal summer solstice, with fewer occurrences and shorter durations in equinox seasons. Our results also suggest that the occurrence of plasma bubbles and GPS scintillations over Africa are well correlated, with scintillation intensity depending on depletion depth. A question remains about the possible physical mechanisms responsible for the difference in the occurrence phenomenology of EPBs and GPS scintillations between different regions in equatorial Africa.

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We investigated longitudinal advancement of the peak Total Electron Content (TEC) within the equatorial anomaly region of Kenya, based on the data from the two Scintillation Network Decision Aid (SCINDA) Global Positioning System (GPS) receivers at Jomo Kenyatta University of Agriculture & Technology (JKUAT): latitude −1.095, longitude 37.015, and at the University of Nairobi: latitude −1.274, longitude 36.808; and the two Geographical Information System (GIS) stations at Malindi: latitude −2.996, longitude 40.194, and at the Regional Center for Mapping of Resources for Development (RCMRD): latitude −1.221, longitude 36.893. The retrieved archived data from these stations were for 17 th December 2009; and for 26 th , 27 th and 28 th August 2010 -just after the solar minimum period of 2008. They were subjected to analysis by the GPS-TEC analysis application software provided by Boston College Research Institute (USA). Results reveal that the peak TEC within the region of study occurs between 8 a.m. and 10 a.m. The Coastal region experiences peak TEC earlier than Nairobi region. Slight variations were also observed on the TEC plots from various stations. It can be concluded that the peak TEC advances westwards within the equatorial anomaly region; these variations are due to plasma bubbles that take place from the east to west within the equatorial region.

This study investigates the variability and periodicity of minimum temperature, maximum temperature and sunspot number-a solar activity index in selected synoptic stations across Nigeria from 1946 to 2010. Annual and semiannual effect of solar activity on minimum temperature was observed in all the six stations. This was indicated in the occurrence of modal periodicities of 6-month and 12-month observed across the six synoptic stations. The synoptic stations are Sokoto (13.01˚N, 5.15˚E), Ilorin (8.29˚N, 4.35˚E), Ikeja (6.35˚N, 3.20˚E), Enugu (6.28˚N, 7.33˚E), Port-Harcourt (4.51˚N, 7.01˚E) and Maiduguri (11.51˚N, 13.05˚E). Similarly, the trends of inter-decadal variability of minimum and maximum temperature show a non-uniformity increase over the analyzed period with a slight decrease before 1960. The long term behavior of minimum and maximum temperature shows a warming rate which ranges from 0.1˚C/decade to 0.2˚C/ decade across the six stations except for maximum temperature at Ilorin and minimum temperature at Sokoto which is at −0.2˚C/decade and 0.3˚C/decade respectively.

The study sought to determine effects of occupational safety and health awareness among on work environment in the Kenyan Kisumu County Water Service industry. The study utilized a descriptive research design. The target population consisted of employees of Kisumu Water and Sewerage Company (KIWASCO) and Lake Victoria South Water Service Board (LVSWSB) working in water treatment works, waste water treatment plants and construction sites. From population of 410, Sample size was determined using standard formula by Fisher (1983). Since the population was <10,000, the formula by Mugenda & Mugenda, (2003) was applied and 81 number of Questionnaires used to obtain primary data finally analyzed using quantitative techniques. A simple random sampling was employed to draw the respondents from each site and selfadministered semi-structured questionnaire was used to acquire data. The data was analyzed using Statistical Package for Social Sciences version 21. Frequencies and percentages were obtained and correlations done using Spearman's correlation coefficients. On the respondents organizations, majority at 57(75%) worked at KIWASCO, 12(15.79%) worked at LVSWSB while the minority at 7(9.21%) worked at GULF. Preponderance of the respondents at 61(80.3%) were males while the least at 15(19.7%) females. Most of the respondents at 28(36.6%) were between 29-39 years of age while the same number of respondents forming the minority at 24(31.6%) were both between 18-28 years and 40-50 years of ages. Preponderance of the respondents at 61(80.3%) had attained college level of education as their highest, 9(11.8%) attained secondary while the minority at 6(7.9%) had attained primary level of education as their highest. On the number of years worked for the organization, majority at 27(35.5%) had worked for 4 years, 24(31.6%) had worked 1 year, 15(19.7%) had worked for 3 years while the least number of respondents at 10 (13.2%) had worked for 2 years for their organization. Preponderance of the respondents at 49(64.5%) stated that water supply was their nature of work, 14(18.4%) stated construction as their nature of work while the minority at 13(17.1%) stated waste water as their nature of work. This research found that awareness of existence of Safety and Health Act of 2007 was to a large extent, mean =3.80, SD=1.200. It was critical for staff to master occupational safety regulations to a large extent, mean= 4.36, SD=0.948, same applying to the importance of knowing and following safe work procedures mean=4.49, SD=0.931. Majority of the respondents were aware of the instructions to follow for safe working practices, mean of 4.38, SD=0.879. The mean of mean was 4.12 denoting that the respondents were aware of occupational safety and health to a large extent. The study analyzed the relationship between staff awareness of occupational safety and health and work environment using Spearman's rho coefficient ,Confidence Level (CL) = 95%, It was established that there is a significant moderate positive relationship between staff awareness...

Among the Concentrated Solar Collector (CSC) technologies, Parabolic Trough Collector (PTC) is the most mature and commercialized CSC technology today. Currently, solar PTC technology is mainly used for electricity generation despite its huge potential for heating, especially in industrial process heat (IPH) applications. Though the technology is well-developed and successfully used in many developed countries, there is barely any development in Kenya. This paper studies the techno-economic feasibility of a solar PTC-assisted tea drying process in one tea factory that currently relies on biomass for process heat, in the tea producing area of Kericho, Kenya. The plant integrating parabolic troughs is modelled and a yearly simulation performed using System Advisor Model (SAM) software. The weather data are derived from ground measurements at Kericho meteorological weather station. SAM is used to model the impact of the principal design parameters, i.e., solar multiple (SM), thermal energy storage (TES) and hybridization percentages, on solar–biomass plant configurations, and to reveal the optimum case. The studied impacts are linked to the annual energy production and the optimal size which minimizes the levelized cost of heat (LCOH). Analysis of monthly variations of energy production by the solar PTC reveals that even when the solar system is designed to its maximum capacity (SM of 3 and TES of 24 h), some months will still require hybridisation with biomass to fully meet the energy demand. TES must also be incorporated in the solar PTC design to maximise on energy production. The hybrid solar–biomass plant with TES provides optimal performance when SM is 1.8 and TES is 24 h. This results in LCOH of 1.85 US cents/kWh, which is 25% cheaper than using biomass only as is the current practice. Furthermore, integration of solar PTC has a positive impact on carbon footprint and considerably reduces annual greenhouse gas (GHG) emissions by 9817 tons of CO2-eq, and annual fuel wood consumption by 16,462 m3 (equivalent to 23.51 acres of mature grown trees).

Fisher (1983). Since the population was <10,000, the formula by Mugenda & Mugenda, (2003)