Factors Affecting Biogas Production during Anaerobic Decomposition of Brewery effluent- wastewater in a Fluidized Bed Digester.

This  work determined the dependency of biogas and carbon (iv) oxide production on microbial concentration X (Cfu/l), hydraulic retention time (HRT), ratio of total volatile fatty acid (TVFA) and total alkalinity K, during anaerobic decomposition of brewery effluent wastewater in a fluidized-bed reactor system. The volume of biogas and carbon (iv) oxide produced were monitored as the treatment time progressed. For  brewery waste water volume of 2 litres treated in the bioreactor, the volume of biogas rich in methane, produced in this work was described as s-curve with initial volume of biogas produced as 0.003l  at 4h HRT and maximum volume of 0.0045l at 8 h HRT.Similarly,0.0033l of carbon(iv)oxide was recorded at 2 h HRT and it achieved its maximum of 0.0042l at 8 h HRT. Total microbial count was conducted on the reactor sample water. The maximum concentration of the gases recorded at 8 h HRT corresponded to the favourable operating environment and good system stability ratio  (VFA/Alkalinity)<0.5 achieved. Key words: Anaerobic decomposition, brewery wastewater, fluidized-bed reactor, Biogas, carbon (iv) oxide

Psychosocial Predictors of Drug Involvement Among Secondary School Students

Predictors of drug involvement among secondary school students in Ibadan were examined in this study. Two hundred and four (204) students comprising 113 males and 91 females, whose age ranged between 13 and 25 years (M = 16.32, S.D. = 1.81) participatedin the study. Data collected with a structured questionnaire were subjected to independent sample t-test, and regression analysis. Psychosocial factors (life purpose, need for achievement and self-esteem) significantly predicted drug abuse [F (6, 113) = 7.75; p < .01, R2 = .29]. Participants with low score on life purpose reported higher substanceabuse than those with high score on life purpose, t (161) = 2.62, p <.05 ; those with low score on the need for achievement reported higher substance abuse than those with high score on the need for achievement, t (162) = 4.09, p < .01 ; those with low score on the need for achievement reported higher substance abuse than those with high scoreon the need for achievement t (162) = 2.62, p <.05; female participants reported higher substance abuse than male counterparts, t (176) = - 4.05, p <.01). In conclusion, it is expedient that efforts be intensified on actions that will reawaken the strive for excellence and sense of self worth through engagement in self development activities, thereby minimizingthe prevalence of substance abuse among Nigerian youths

Radiation Shielding Properties of Synthetic Ca-Al2O3 Polymer Based Composites

Ionizing radiation exposure from medical diagnostic equipment, industries, nuclear research facilities, and nuclear weapon development has led to health impacts such as cancer and acute radiation syndrome, necessitating the use of proper radiation shielding. The optical and radiation shielding capabilities of Ca-Al2O3 polymer-based composites were explored in this article. The composites were made by combining synthesized Aluminum oxide (Al2O3) with calcium (Ca) formed from Periwinkle shells, Snail shells, and Seashells and calcining them at 1000 oC for 13 hours. The synthesized Ca-Al2O3 powders were dispersed into polymeric materials in a ratio of 1:1 using an effective melt-mixing process, then cast in a 10 cm by 10 cm square Mold with a thickness of 10 mm and allowed to set overnight at ambient temperature. The composite samples obtained were transferred to the Nigerian Nuclear Regulatory Agency (NNRA) in Ibadan for radiographic examinations and analyses. X-ray transmission through the manufactured composites samples was investigated using a well-collimated point source. The produced x-rays' initial intensity (Io) was determined. With the sample in front of the detector, the transmitted x-ray beam (I) was measured. The measurements were repeated three times for each composite sample, and the average value was calculated. Using relevant and referenced equations, the linear attenuation coefficient, half-value layer, relaxation length, and absorbance for each sample were calculated. The radiation shielding composites' x-ray photon absorptions were determined using transmission data by Beer's Lambert law. The XRF results revealed that the calcined samples were mostly calcium with only a few traces of other elements, with percentage calcium quantities of approximately 32, 37, and 34 for snail shells, seashells, and periwinkle shells, respectively, and the XRD result confirmed the Al2O3 polymorphs at approximately 32o and 57 o and the Aluminum phase at 46 o. For the three radiation shielding composites under investigation, the x-ray photon transmittance is quite low at 40 keV to 60 keV and comparatively high at 100 keV to 200 keV. From 100 keV to 200 keV, the transmittance of periwinkle shells and snail shell calcium sources polymer-based composites was similar, and their differences became significant at lower energies. For Ca-Al2O3 polymer-based composites with calcium contents sourced from seashells, periwinkle shells, and snail shells, the maximum linear attenuation coefficients were 1.0 cm-1, 0.79 cm-1, and 0.65 cm-1, respectively. At 60 keV and below, the radiation shielding composites have the highest attenuation coefficient. The half-value layer (HVL) of all the samples under investigation reduced abruptly at 40 and 60 keV and grew linearly as the energy increased from 100 to 200 keV. The relaxation length is comparatively low at 40 and 60 keV compared to other x-ray sources utilized at higher energies. Each radiation shielding composite's properties are determined by the amount of calcium present in the samples. Over a certain photon energy range (40 keV–200 keV), the Ca-Al2O3 polymer-based composites with calcium contents sourced from seashells were found to have higher x-ray attenuating characteristics than other composites. The attenuating capacity of all the composites under this study can be enhanced by increasing the radiation shielding composite thickness.     &nbsp

Energy neutral protocol based on hierarchical routing techniques for energy harvesting wireless sensor network

Recently, researchers in the field of wireless sensor networks have resorted to energy harvesting techniques that allows energy to be harvested from the ambient environment to power sensor nodes. Using such Energy harvesting techniques together with proper routing protocols, an Energy Neutral state can be achieved so that sensor nodes can run perpetually. In this paper, we propose an Energy Neutral LEACH routing protocol which is an extension to the traditional LEACH protocol. The goal of the proposed protocol is to use Gateway node in each cluster so as to reduce the data transmission ranges of cluster head nodes. Simulation results show that the proposed routing protocol achieves a higher throughput and ensure the energy neutral status of the entire network

An improved ant colony optimization algorithm with fault tolerance for job scheduling in grid computing systems.

The Grid scheduler, schedules user jobs on the best available resource in terms of resource characteristics by optimizing job execution time. Resource failure in Grid is no longer an exception but a regular occurring event as resources are increasingly being used by the scientific community to solve computationally intensive problems which typically run for days or even months. It is therefore absolutely essential that these long-running applications are able to tolerate failures and avoid re-computations from scratch after resource failure has occurred, to satisfy the user's Quality of Service (QoS) requirement. Job Scheduling with Fault Tolerance in Grid Computing using Ant Colony Optimization is proposed to ensure that jobs are executed successfully even when resource failure has occurred. The technique employed in this paper, is the use of resource failure rate, as well as checkpoint-based roll back recovery strategy. Check-pointing aims at reducing the amount of work that is lost upon failure of the system by immediately saving the state of the system. A comparison of the proposed approach with an existing Ant Colony Optimization (ACO) algorithm is discussed. The experimental results of the implemented Fault Tolerance scheduling algorithm show that there is an improvement in the user's QoS requirement over the existing ACO algorithm, which has no fault tolerance integrated in it. The performance evaluation of the two algorithms was measured in terms of the three main scheduling performance metrics: makespan, throughput and average turnaround time

Average makespan for varied Gridlets.

<p>Average makespan for varied Gridlets.</p

Average makespan time for varied number of faults (total number of Gridlets = 3,000).

<p>Average makespan time for varied number of faults (total number of Gridlets = 3,000).</p

Average turnaround time for varied number of Gridlets.

<p>Similar experiments were carried out by keeping the number of Gridlets constant and varying the number of resources. Figs <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0177567#pone.0177567.g006" target="_blank">6</a>, <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0177567#pone.0177567.g007" target="_blank">7</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0177567#pone.0177567.g008" target="_blank">8</a> gives the results obtain as the number of Gridlets is kept constant with varied number of resources. In this experiment, 3,000 jobs are sent to the Grid with varying number of resources from 50 to 3,050, and as can be seen, increasing the number of resources has a decreasing exponential effect on the execution time. The proposed algorithms perform better when there is a small number of resources and a large number of jobs.</p

Average throughput time for varied resources.

<p>Average throughput time for varied resources.</p