Structure and Transport Coefficients of Liquid Argon and Neon using Molecular Dynamics Simulation

Molecular dynamics simulation was employed to deduce the dynamics property distribution function of Argon and Neon liquid. With the use of a Lennnard-Jones pair potential model, an inter-atomic interaction function was observed between pair of particles in a system of many particles, which indicates that the pair distribution function determines the structures of liquid Argon. This distribution effect regarding the liquid structure of Lennard-Jones potential was strongly affected such that its viscosity depends on density distribution of the model. The radial distribution function, g(r) agrees well with the experimental data used. Our results regarding Argon and Neon show that their signatures are quite different at each temperature, such that their corresponding viscosity is not consistent. Two sharps turning points are more prominent in Argon, one at temperature of 83.88 Kelvin (K) with viscosity of -0.548 Pascal second (Pa-s) and the other at temperature of 215.64 K with viscosity of -0.228 Pa-s. In Argon and Neon liquid, temperature and density are inversely and directly proportional to diffusion coefficient, in that order. This characteristic suggests that the observed non linearity could result from the non uniform thermal expansion in liquid Argon and Neon, which are between the temperature range of 21.98 K and 239.52 K

Exercise-induced bronchospasm and its associated factors among secondary school students in an urban community

Introduction: Exercise-induced bronchospasm (EIB) is a transient narrowing of the airway that usually occurs shortly after exercise. It occurs commonly in people with asthma; however EIB has also been reported in individuals without clinical asthma. The study aimed to determine the prevalence and factors associated with EIB among secondary school students. Methods: It was a descriptive cross-sectional school- based study involving secondary school students aged between 10 and 17 years without previous history of asthma. Subjects undertook a six-minute running test, spirometry was done and the best of three FEV1 readings were obtained pre-exercise, at 5, 10, 15 and 30 minutes post exercise. The diagnosis of EIB was made when there was a decrease in FEV1 of ≥10% from baseline after exercise. Results: Of the 265participants studied, 34 (12.8%) had EIB at 5 minutes post exercise. EIB was significantly more in the 10–13 years age group (χ2 = 18.416, p = <0.001), there was no significant gender difference. The presence of allergic (vernal) conjunctivitis and rhinitis were both significantly associated with the development of EIB (χ2 = 13.574, p < 0.001 and 0.011 respectively). There was no significant association with previous history of wheeze and exposure to indoor air pollution such as cooking with biomass fuel and parental cigarette smoking. Conclusion: EIB exist among non-asthmatic school children, and it is more frequent in the early adolescent age-group. Students with allergic conjunctivitis and rhinitis are more likely to manifest exercise induced bronchospasm

An evaluation of the phytotoxicity of municipal solid waste during co-composting with different animal manures

Composting is a bioxidative process carried out under controlled conditions which utilizes naturally occurring microorganisms for organic waste recycling. In this study, a 60 days cocomposting experiment of different treatment consisting of municipal solid wastes and plant wastes with cow dung, poultry dropping and swine manure were investigated.Compost maturity parameters and phytotoxicity, during co-composting of municipal solid waste (MSW) with different animal manures (3:1 w/w) were evaluated. Four composting treatment set-ups: MSW (control), MSW+Swine Manure (SM), MSW+Poultry Manure (PM) and MSW+Cattle Manure (CM) were prepared and composting carried out for 60 days. Changes in temperature and pH were measured daily while Electrical Conductivity, Organic Matter, Total Organic Carbon, Total Kjedahl Nitrogen, and carbon/nitrogen ratios were assessed at day 0 and day 60. Humification process and phytotoxicity of the treatments were assessed at days 0, 10, 20, 30, 40, 50 and 60, using maize seeds germination bioassays. MSW+PM treatment showed the highest temperature of 63ºC during the thermophilic phase while the control showed the least. The pH at the end of composting in all treatments exhibited alkaline values with MSW+CM showing the highest value of 8.6. Maturity indices showed that there were significant decreases in organic matter, C/N and NH4+ -N/NO3- -N ratios in all the treatments when compared with the control. At the end of   composting, Germination index( GI) values varied from 52.56 to 97.23% with MSW+PM showing the highest germination index (GI?) of 97.23±6.08% followed by MSW+CM and MSW+SM with GI values of 88.4±6.3 and 84.8±5.3% respectively. The germination index indicated that there were significant reductions in the phytotoxicity of the treatments. Keywords: Composting, municipal solid waste, phytotoxicity, poultry manure, seed germination tes

Economic evaluation of the impact of the privatisation policy on animal health delivery services in africa: a case study of Zimbabwe

In many countries in Africa, the delivery of animal health services, especially in rural areas, is far from adequate. These services therefore need restructuring. An analysis of these systems indicates that the development of an appropriate analytical framework for evaluating them would prove to be extremely valuable. Such a framework should be able to identify, qualify and quantify, the various segments of the population, their spatial distribution, and specific health care needs, as well as permit the prediction and evaluation of the socio-economic impact of policies and interventions on the delivery system. In order to develop such a framework, a project was undertaken using the concept of Precision Service Delivery (PSD), with the objective of developing a robust analytical framework which is universally applicable to all health care delivery systems. PSD is aimed at adjusting and "fine-tuning" the delivery of services, so as to meet the specific health care needs of the different segments of the population, in the context of their geographical location. The animal health care delivery system in Zimbabwe was used as a case study. The PSD framework was used in this study, to analyse the economic and social impact of different scenarios of the current privatisation oriented policy reforms. This involved the use of statistical techniques, a geo-spatial modelling technique and Linear Programming mathematical models. A questionnaire survey of 145 livestock producers was conducted with representation from all four livestock production systems in Zimbabwe. The objective was to evaluate the socio-economic and health care variables that characterise the production systems. From fourteen putative variables identified, eight were extracted using Principal Component Analysis, as a bases for characterising the existing livestock production systems. Using Multiple Discriminant Analysis, the validity of the different production systems as distinct classes was confirmed

OPTIMIZATION AND PROGNOSTIC MODEL FOR SPLITTING TENSILE STRENGTH OF CONCRETE PRODUCED FROM GRANITE AND RECYCLED CONCRETE AGGREGATE

 Using recycled concrete aggregates from structural demolition wastes is presenting a potential application in the building industry as a substitute for natural aggregates. It preserves natural resources and brings about a reduction in the space needed as landfill disposal sites. This research was aimed at developing a prognostic model for splitting tensile strength of concrete produced from granite and recycled concrete aggregate. Thirteen rounds of experiments were considered utilizing the Central Composite Response Surface method. Granite was replaced with Recycled Concrete Aggregate (RCA) in varying proportions from 0% to 100% while the water-cement ratio (w/c) was varied from 0.3 to 0.7. Samples were subjected to test after 7, 14 and 28 days curing. It was observed that with a surge in the fraction of RCA, the splitting tensile strength reduced at all levels of w/c ratio. 30% RCA at 0.5 w/c gave the optimum combination that resulted in the highest splitting tensile strength of 2.11  at 28 days. This result is 7.9 % lesser than the control splitting tensile strength of 2.2

Resistance of strains of rice weevil, Sitophilus oryzae (Coleoptera: Curculionidae) to pirimiphos methyl

Insecticidal resistance of five strains of Sitophilus oryzae (L.) to pirimiphos methyl (Actellic®) was investigated in the laboratory at 28 ± 2oC and 89 ± 5% relative humidity. Rice infested by S. oryzaewas sampled from Nigerian stores in Akure (Ondo state), Ibadan (Oyo state), Ikotun (Lagos state) and Ilesha (Osun state) and a laboratory culture (in Akure). Twenty adult weevils from each location were exposed to filter papers impregnated with liquid pirimiphos methyl at one of seven concentrations ranging from 0.0 to 5.0%. Mortality rates of the rice weevils were observed at 3, 6 and 24 h after treatment. The mortality of weevils increased with increasing concentration and period of exposure. Irrespective of the strain, 100% mortality was observed in all the treatments at 24 h after exposure to pirimiphos methyl. Weevils sampled from Ibadan were the most resistant, while laboratory strains were the least resistant at 2 and 5% concentrations.Keywords: Strains, insecticide, Pirimiphos methyl, Resistance, Sitophilus oryzae

PHYSICOCHEMICAL PROPERTIES, PROXIMATE COMPOSITION AND SENSORY EVALUATION OF PINEAPPLE FRUIT (Ananas comosus) STORED IN DIFFERENT MEDIA

Provision of adequate storage facility enhances the postharvest quality and shelf-life of fruits. An experiment was carried out in the laboratory of the Department of Horticulture, Federal University of Agriculture, Abeokuta (FUNAAB) to determine the postharvest quality and sensory acceptability of pineapple fruits stored in different media. Pineapple fruits from the Directorate of Farms at FUNAAB were harvested at colour break stage and stored in the evaporative cooling structure (ECS) - pots in pot design and ventilated wooden boxes (VWB) while fruits stored in the open shelf served as the control. The experiment was laid out in completely randomised block design, replicated four times. Shell and pulp colour, physiological weight loss (PWL), total soluble solids (TSS), total titratable acidity, pH, proximate contents and sensory acceptability of the fruits were evaluated at pre-storage and after storage at 11 days (DAS). Quality and sensory attributes of pineapple fruits were affected by storage media. Fruits TSS contents increased with storage time while PWL and vitamin C contents reduced with storage time, across the media. Fruits stored in the ECS had comparable vitamin C content with pre stored fruits. Crude protein, crude fibre and carbohydrate contents were comparable in fruits stored in all media. Shell colour change from green to full yellow was reduced in fruits stored in the ECS and had better sensory acceptability when compared with fruits stored in VWB and open shelf. Pineapple fruit stored in the ECS retained fruit quality with better sensory acceptability     &nbsp

Investigating the optimal combination for gravel and granite in blended palm oil fuel ash concrete

Global production of palm oil in 2022 was estimated at 73 million metric tonnes. The processing of palm oil generates a huge quantity of waste which is often left unprocessed leading to environmental pollution. Gravels are obtained from weathered rocks and are readily available and cheaper than granite as coarse aggregate in concrete. An innovative way of transforming waste into wealth is by incorporating these materials into concrete for construction purposes. Thus, this study was done to obtain an ideal combination of gravel and granite in palm oil fuel ash (POFA)-blended concrete. A water/cement (w/c) ratio of 0.5 in a nominal concrete mix ratio of 1:2:4 was adopted to achieve a strength of 20 N/mm2. The central composite method of optimization was utilized in designing the experiments. The best combination was determined to be 67% gravel, 33% granite and 32% POFA. This combination produced concrete with compressive strength of 23.80 N/mm2 which is 19% higher than the 20 N/mm2 target strength