Indication of pollution in a teaching and research farm reservoir

The production and productivity of a water body is largely dependent on its quality. One major source of water pollution is from the agrochemicals from nearby farmlands. The quality of water in the Obafemi Awolowo University Teaching and Research Farm Reservoir (Ile-Ife, Nigeria) was monitored between October, 1993 and March, 1994. Structured questionnaires were administered to obtain information on the types of agrochemicals in use on the farm. Water samples were collected fortnightly for analyses of the physico-chemical parameters and ionic content of the water. Investigation revealed that 21 agrochemicals had been in use on the farm. The physico-chemical parameters of the water showed that the water was very poor in nutrient. The high concentration of ammonium ion contents of the water shows an indication that the residues of certain agrochemicals got into the water to pollute it. Agrochemicals should be used with great caution on farmlands especially in areas close to water bodies from which man obtains fish and other proteinous foods. This paper also suggests a regular monitoring of water quality of reservoirs in order to pick the earliest signs of pollutio

Five-parameter potential box with inverse square singular boundaries

Using the Tridiagonal Representation Approach, we obtain solutions (energy spectrum and corresponding wavefunctions) for a new five-parameter potential box with inverse square singularity at the boundaries.Comment: 7 pages, 2 figures, 1 tabl

Survivorship Of Anopheles gambiae In Relation To Malaria Transmission In Ilorin, Nigeria

For the first time in Africa, an entomological study went beyond the conventional practice of determining parity and survival rates of field-collected adult anopheline mosquitoes but also related these variables to duration of Plasmodium sporogony and estimated the expectation of infective life. Blood-seeking female mosquitoes were collected in Ilorin, Nigeria, from January 2005 to December 2006, and dissected for ovarian tracheations following WHO recommended techniques. The results indicated an annual mean parous rate of 70.92%, and significantly higher parous rates in the rainy than dry season, which also had very low densities. Mean probability of daily survival of the mosquitoes was 0.80, with annual mean life expectancy of 12.24 days. The probability of surviving the sporogonic cycle was low (< 0.4) but the expectation of infective life was long, especially in the rainy season (mean = 8.31 days). The epidemiological implications of these results were discussed. The An. gambiae population in Ilorin is dominated by older mosquitoes with high survival rates thus, suggesting a high vector potential for the species in the area. These information on the survival rates of An. gambiae in relation to malaria transmission would enhance the development of a more focused and informed vector control interventions

Numerical simulation of turbulent heat transfer and fluid flow in different tube designs

Numerical simulation was carried out to study the heat transfer, friction factor and thermal performance of water inside different tubes induced with different twisted tapes. The purpose is to ascertain which of the tube designs gives the best performance when compared with the plain tube. The tubes were under uniform wall heat flux condition and Reynolds number in the range 5000 ≤ Re ≤ 20000 were considered. RNG &#954; − &#949; equation model was selected for the numerical simulations and RANS equations were employed to render the Navier-Stokes equations tractable. The best performance was obtained when the tube was fitted with alternate-axis triangular cut twisted tape. Its Nusselt number and friction factor are respectively 2.07 – 3.33 and 10.65 – 13.1 times better than that of a plain tube and its thermal performance factor is 1.35 – 1.43 times better than that of the tube with plain twisted tape