8 research outputs found

    Studying the variability in the diurnal and seasonal variations in GPS total electron content over Nigeria

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    The study of diurnal and seasonal variations in total electron content (TEC) over Nigeria has been prompted by the recent increase in the number of GPS continuously operating reference stations (CORSs) across Nigeria as well as the reduced costs of microcomputing. The GPS data engaged in this study were recorded in the year 2012 at nine stations in Nigeria located between geomagnetic latitudes – 4.33 and 0.72° N. The GPS data were used to derive GPS TEC, which was analysed for diurnal and seasonal variations. The results obtained were used to produce local GPS TEC maps and bar charts. The derived GPS TEC across all the stations demonstrates consistent minimum diurnal variations during the pre-sunrise hours 04:00 to 06:00 LT, increases with sharp gradient during the sunrise period (∼ 07:00 to 09:00 LT), attains postnoon maximum at about 14:00 LT, and then falls to a minimum just before sunset. Generally, daytime variations are found to be greater than nighttime variations, which range between 0 and 5 TECU. The seasonal variation depicts a semi-annual distribution with higher values (∼ 25–30 TECU) around equinoxes and lower values (∼ 20–25 TECU) around solstices. The December Solstice magnitude is slightly higher than the June Solstice magnitude at all stations, while March Equinox magnitude is also slightly higher than September Equinox magnitude at all stations. Thus, the seasonal variation shows an asymmetry in equinoxes and solstices, with the month of October displaying the highest values of GPS TEC across the latitudes

    Effectiveness of Azadirachta indica A. Juss (Neem) Seed Oil in Controlling Wood Termite

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    The protection of wood against biodeteriorating agents like termite during processing or in service has call for serious possible approach using new safer, environmental friendly preservatives hence this study therefore evaluated Azadirachta indica seed oil against termite attack on Gmelina arborea and Triplochiton scleroxylon wood. The seed oil was obtained using a soxhlet apparatus and N-hexane as the solvent. The wood was dimensioned into 20x20x20 mm and the seed oil was applied by brushing, dipping and soaking and exposed to termitarium while the absorption rate and weight loss to termite attack were determined. Data collected was analyzed using simple statistics and analysis of variance at \u3b10.05. The antimicrobial properties of the need seed oil are due to the availability of phytochemicals which promote antimicrobial activity. The maximum wood protection against termite of all the methods of application was obtained from soaking. The absorption and weight loss ranged from 11.20 - 43.88 % and 56.50 -61.58 % for G. arborea and T. scleroxylon respectively. However, all the application methods used for the wood treatment proved to be effective over the untreated wood
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