Journal of Scientific and Engineering Research

8-18

Authors: Akpado KA, Umeh OA, Onwujei AI, Obi OC

The last decade has witnessed rapid growth in the deployment of wireless Local Area Networks (WLANs) based on the IEEE 802.11 standard. The IEEE 802.11 Wireless LAN (WLAN) has become a dominant technology for the (indoor) broadband wireless networking. The popularity of IEEE 802.11 networks comes with its low cost, high data rate and seamless handoff. Along with its success, there have been demands to enhance the performance of the IEEE 802.11b. To meet such needs, the IEEE 802.11 Working Group (WG) has been developing new protocols to amend the existing protocols. In general, IEEE 802.11b networks operate on either PCF (Point co-ordination function) or DCF (Distributed co-ordination function) mode. This research work mainly focuses on DCF mode for IEEE 802.11b standard. Real time measurement of an existing network performance (throughput) was carried out. WLAN performance analysis was presented. The study was carried out to establish the influence of number of workstations and traffic distribution/patterns on IEEE802.11b QoS parameters. WLAN network model was developed and simulated using MATLAB Simulink environment. The result showed that the performance of IEEE 802.11b WLAN deteriorate as the traffic loading increases and that Gamma Traffic Distribution has the best performance in terms of throughput than the Exponential and Geometric Traffic Distributions. The Real time measurement of throughput result was used to validate our proposed Matlab model.

27-34

Authors: Araviadis Romanos-Vasileios

The use of treated urban wastewater as a resource for irrigation water is a practice widely employed in arid and semi-arid regions of the world but also one that is expected to become more diffuse due to the reduction of water resources and the climax in the competition for water. Researchers’ interests are, thus, focused on investigating the effects of the method under question on the crops on which it is applied. This review presents the main research findings on the topic with a special reference to research carried out in Greece. The general conclusion of the present review is that the use of treated urban wastewater in irrigation can have beneficial effects on most crop yields, provided that quality characteristics of both treated wastewater and crops are sufficiently monitored.

40-44

Authors: Sayantani Ghosh, Samir Kumar Bandyopadhyay

Anthropology describes the scientific study of the origin, the behaviour, and the physical, social, and cultural development of humans. Forensic anthropologists are trained physical anthropologists who apply their knowledge of biology, science, and culture to the legal process. They identify human remains, along with pathologists, homicide detectives and other specialists. Age determination of unknown human bodies is important in the setting of a crime investigation or a mass disaster because the age at death, birth date, and year of death as well as gender can guide investigators to the correct identity among a large number of possible matches. Traditional morphological methods used by anthropologists to determine age are often imprecise.

55-63

Authors: Abalaka M Enemaduku, Idakwoji K, Daniyan S Yahaya

This study was conducted to determine the effects of pesticide application on soil microbial spectrum using a herbicide (Glyphosate; the active ingredient in Roundup) and an insecticide (Chlorpyrifos). The control soil samples had no pesticide application. Soil samples taken at the depth of 0-20cm from the Biological Garden was taken to the laboratory. The soil was sieved through a 2mm mesh to remove stones and plant debris. One kilogram of the soil samples was weighed and transferred into different containers into which 150ml of the dissolved pesticides were applied. The numbers of colony forming units (CFU) of respective groups of microorganisms were determined on Nutrient Agar and Sabouraud Dextrose Agar media by pour plate method. After 1, 7, 14 and 21 days of experiment, the number of bacteria and fungi were estimated. At the end of the study, results revealed that pesticide applications caused reduction in microbial population present in the soil when compared with the control. Also, despite the reductions, bacterial species like Bacillus subtilis developed tolerance possibly due to its characteristic spore formation, others like Pseudomonas aeruginosa disappeared immediately after pesticide treatment only to reappear and start multiplying after some days. This may be due, in part, to evolution and development of metabolic mechanisms to use the pesticides as a carbon and energy source. Using a paired t-Test, calculated value of 14.9 for Glyphosate and 24.1 for Chlorpyrifos is greater than t-tabulate value at 0.05 confidence level, indicating that there is a great difference between microbial population in pesticide treated soil and non-treated soil confirming the effects of microbial population reduction and possible extinction due to pesticide application on the soil.

71-77

Authors: Udonne JD, Odunlami MO, Akinyemi OP

The effects of corrosion and the inhibitive effects of plants extract were investigated on samples of mild steel immersed in Hydrochloric acid. Findings have shown that inorganic chemicals used to inhibit corrosion of some organic material, are also suitable for corrosion inhibition of metals and their alloys. Extracts of mango and sweet orange were investigated for their inhibitive effects. In this study, corrosion inhibition of mild steel coupons was carried out on 1.0M solution of hydrochloric acid media through the application of mango peel extract (Mangifera indica) and orange peels extract (Citrus sinensis) which are organic materials. The method of mass loss test experiment was employed for ten days, at room temperature. Energy dispersed x-ray spectrometer (EDX 3600B) was used to analyze a coupon of the mild steel used before the commencement of the experiment. The results confirm that mango (Mangifera indica) is capable of inhibiting corrosion of steel in inorganic acids. The results further show that inhibition by the inhibitors of steel in inorganic acid environment depends on the relative concentration of the inhibitors applied. For example, 1.0 g per litre of each of the inhibitors inhibits better than 0.2 g per litre of same. Mango peel extract has proved to be slightly more effective in HCl solution for mild steel inhibition as revealed by the results.

85-91

Authors: Oginni OI

The paper examines the body components as determinants of academic achievement of students in mathematics. Ex-post facto research design was adopted for the study; the population for the study comprises of all the Senior Secondary school (SSS3) students, while the sample for the study was made up of 1800 students randomly selected by using multi-stage technique across five states in the South-Western part of Nigeria. The instruments used for the study consisted (i) Achievement Test in Mathematics (ATM) (ii) Standardized Body Measuring devices (SBMD) (iii) Students Body Parameters and Bio-data Inventory (SBPBI). The face, content and construct validity of the instruments were ensured. The reliability of the instruments was estimated using the split half and Crombach Alpha formula and yielded 0.89 and 0.76 reliability coefficients respectively. The findings of the study revealed that there was a positive significant multiple relationships between performance in Mathematics and body components. Also the better the sizes of the head circumference, height, arm length, neck circumference, hip circumference and BAI the better the contribution to the performance of students in Mathematics. The study further revealed that the head circumference is the best determinant of academic achievement of students in Mathematics while the BMI is the worst determinant academic performance in Mathematics. Based on the findings, it was recommended that pregnant women should henceforth continually be placed on balance diet by the medical personnel in order to enhance proper development of all the organs and bodily parts of fetuses.