LES Modelling of Propagating Turbulence Premixed Flames using a Dynamic Flame Surface Density Model

A Dynamic flame surface density (DFSD) model, developed recently from experimental images for transient turbulent premixed flames, is implemented and tested using the large eddy simulation (LES) modelling technique. Numerical predictions from DFSD model are compared with those predicted using the flame surface density (FSD) sub-grid scale (SGS) model for reaction rate. In the SGS-DFSD model, dynamic formulation of the reaction rate is coupled with the fractal analysis of the flame front structure. The fractal dimension is evaluated dynamically from an empirical formula based on the sub-grid velocity fluctuations. A laboratory scale combustion chamber with inbuilt solid obstacles is used for model validation and comparisons. The flame is initiated from igniting a stichiometric propane/air mixture from stagnation. The results obtained with the DFSD model are in good comparisons with experimental data and the essential features of turbulent premixed combustion are well captured. It has also been observed that the SGS-DFSD model for reaction rate found to capture the unresolved flame surface density contributions. Further investigations are planned to examine and validate of the SGS-DFSD for different flow geometries

Adsorption and Biodegradation of 1-Methyl Naphthalene Using Immobilized Pseudomonas macerans and Bacillus subtilis on Burnt Kaolin

This work is aimed at assessing the effect of incorporating Pseudomonas macerans and Bacillus subtilis on burnt kaolin (BK) during the biodegradation of 1-methyl naphthalene. The biodegradation was monitored by determining the concentration of CO2 released. Immobilized Pseudomonas macerans on BK released CO2 in the range of 0.72 - 0.83 mg/L, while this was 0.68 - 0.78 mg/L with Bacillus subtilis; for the degradation alone the range was 0.39 - 0.46 mg/L after 72 h. Generally, the concentration of carbon (IV) oxide released by the immobilized Pseudomonas macerans was more than that by Bacillus subtilis. Therefore, immobilization using BK resulted to better removal of the organic pollutant. The FTIR indicated presence of new peaks within the regions 3272-3265cm-1 and 1647-1640cm-1 attributed to overlapping of hydroxyl (-OH) and carbonyl (C=O) stretching in carboxylic acid. The absorptions within 1114-1088 cm-1, and at 1408cm-1 are due to C-O stretching and O-H in plane bending of carboxylic acid respectively. The use of kaolin for environmental clean-up of organic pollutants will enhance the value chain of solid minerals in Nigeria

Household Expenditure on Treatment of Presumptive Malaria in a Rural Community of North-western Nigeria

Background: Malaria is endemic in Nigeria and there is a vicious cycle between it and poverty. It contributes towards poverty, while poverty influences the risk of its infection. Majority of Nigerians, 70%, live in rural areas, below poverty line. They earn less than $1.25 a day. Subsistence farming is their main occupation. The cost of malaria treatment represents a significant portion of their income.Objective: This study was conducted to assess the direct cost of presumptive malaria treatment on households in Gimba Village of Soba Local Government Area of Kaduna State, Nigeria.Methodology: A cross-sectional descriptive study conducted during community diagnosis posting of final year medical students of Ahmadu Bello University, Zaria in July 2012. An interviewer- administered questionnaire was used to collect data from household heads.Results: Most of the respondents (69.7%) were farmers. A large proportion of the respondents (47.3%) earned between N10,000.00 to N20,000.00. monthly. The average household size was 6 while the average number of presumptive malaria cases per household per year was 13. On average, the direct cost of presumptive malaria treatment alone, consumes 4.9 % of the annual income of household heads. There was a statistically significant association between cost of treatment and place of seeking treatment (p <0.001).Conclusion: The direct cost of presumptive malaria treatment alone consumed a large proportion of the meagre annual income of households in the study area. For effective malaria control in Nigeria, free or subsidized malaria treatment and rural health insurance scheme are recommended.Keywords: Household, expenditure, Treatment, presumptive malaria, Gimba Community, Nigeria

Ipomea asarifolia (Desr), A Potential Cover Crop for Soil Fertility Improvement in The Sudan Savanna Region, Nigeria

The effect of Ipomea asarifolia on physico - chemical properties of the soils at Usmanu Danfodiyo University, Sokoto main campus, in the Sudan Savanna of Nigeria was investigated. The study determined the effect of the plant on some physical and chemical properties of soils, found out the nutrient retention ability of the plant in the soils and the variation of the effect with distance within the plants’ canopy. A total of 48 samples were collected from four different sites within Usmanu Danfodiyo University main Campus; VC complex area, University stadium area, Behind new library area and opposite IBB centre area and four distances from the plant (control, plant base, 0.5 m and 1 m from the plant base). Samples were collected for use in a randomized complete block design (RCBD) experiment with three replicates. Soil pH, Organic C, CEC, total N, available P, K, Ca and Mg concentrations were determined, particle size analysis was also carried out. The results were subjected to analysis of variance (ANOVA), where significant F values were obtained, the means were separated by Duncan multiple range tests (DMRT). The difference among the sites and the distances were found to be statistically significant (P VC complex area > New library area > IBB centre area. On the other hand, the effect on all the parameters was found to decrease with distance from the plant with the base of the plant having the highest organic C, CEC, total N, available P and exchangeable K, Ca and Mg; 6.83 g kg-1, 5.00 cmol kg-1, 0.42 g kg-1, 10.82 mg kg-1 and 0.26, 0.50 and 0.97 cmol kg-1 respectively, while the control soils had the least values; 3.46 g kg-1, 4.00 cmol kg-1, 0.12 g kg-1, 7.43 mg kg-1, 0.21, 0.38, and 0.45 cmol kg-1 respectively. The effect was attributed to the accumulation of organic matter around the plant and its ability to prevent erosion by both water and wind thus retaining nutrients making it a suitable cover crop for soil fertility improvement

Fasting of Ramadan in peoples with diabetes in Benghazi, Libya: an exploratory study

Background: The epidemiology of diabetes and Ramadan fasting was reported from many Muslim countries, but not from Libya. Methodology: We interviewed 493 consecutive diabetic patients at Benghazi Diabetes and Endocrine Center for the potential complications of fasting during Ramadan. Results: We found 70% of diabetic patients completed the 30 days of Ramadan fasting. Hypo- and hyperglycemia was the most commonly reported complications especially during the first two weeks of Ramadan month. Conclusion: It seems majority of diabetic patients in Libya manage to fast during Ramadan month. Patient education and early planned adjustment of diabetic medication is needed to decrease the frequency of diabetic complication during Ramadan month

Large perturbations in CO2 flux and subsequent chemosynthesis are induced in agricultural soil by the addition of elemental sulfur

The microbial contribution to soil organic matter has been shown to be much larger than previously thought and thus it plays a major role in carbon cycling. Among soil microorganisms, chemoautotrophs can fix CO2 without sunlight and can glean energy through the oxidation of reduced elements such as sulfur. Here we show that the addition of sulfur to soil results in an initial surge in production of CO2 through microbial respiration, followed by an order of magnitude increase in the capture of carbon from the atmosphere as elemental sulfur is oxidised to sulfate. Thiobacillus spp., take advantage of specific conditions to become the dominant chemoautotrophic group that consumes CO2. We discern the direct incorporation of atmospheric carbon into soil carbohydrate, protein and aliphatic compounds and differentiate these from existing biomass. These results suggest that chemoautotrophs can play a large role in carbon cycling and that this carbon is heavily influenced by land management practises

Brown macroalgae as bio-indicators for heavy metals pollution of Al-Jubail coastal area of Saudi Arabia

Wastes from both industrial and domestic sources, as well as habitat destruction have a substantial impact on the coastal environments. It causes serious problems in many countries and for several seas and oceans which leads to the extinction of several plant and animal species. Many water resources are no longer suitable for drinking or for agriculture as a result of pollution. The main aim of this study was to investigate the efficiency of four brown macroalage as bioindicators for toxic heavy metals (manganese (Mn), copper (Cu), zinc (Zn), arsenite (As), cadmium (Cd), and lead (Pb)) along Al-jubail industrial city coast at Persian Gulf (Saudi Arabia). Brown macroalage samples were collected from three different sites in three time points, January, March and May, 2010. The four collected brown macroalgae were identified as Sargassum angustifolium, Sargassum boveanum, Sargassum latifolium, and Padina gymnospora. The algal samples were cleaned using sea water and distilled water, dried, and the concentrations of various toxic metals were determined. The average concentrations of Mn, Co, Ni and Cd were within the expected limits of un-contaminated areas. However, the results indicate the high level of Zn ion accumulation in all tested brown algae, showing highest concentration in S. angustifolium > P. gymnospora > S. latifolium > S. boveanum with highest Zn concentration of 991 ± 49.1, 988 ± 47.5, 980 ± 44.2, and 911 ± 39.7 µg g-1 dry weights, respectively. In addition, Cu was detected at high concentration of 92.1 ± 3.7 ìg g-1 dry weight in S. boveanum. These results clearly indicate the high pollution levels of Al-jubail industrial city coast with Zn and Cu toxic heavy metals, which is mostly due to uncontrolled disposal of industrial waste into coastal area. Furthermore, the consistency of Zn concentrations in all tested brown algae indicated the efficiency of the tested algae, including P. gymnospora, S. angustifolium, S. latifolium, and S. boveanum, for bioaccumulation and bio-monitoring studies of Zn.Key words: Brown algae, heavy metals, bio-indicators, Sargassum sp., Padina sp