LINEARISATION TECHNIQUES: THE KEY TO THE USE OF MORE EFFICIENT MODULATION SCHEMES AND RF POWER AMPLIFIERS

This paper gives a brief description of linear modulation schemes and how they are more efficient for data communication. Different classes of RF power amplifiers with respect to their efficiencies are also discussed, as well as different linearisation techniques presently in use and those at the research and developmental stage. This paper illustrates with examples how more efficient modulation schemes and more efficient classes of RF power amplifiers can be adopted for use in data communications, if the inherent problem of spectral spreading ,which results from non-linear output of RF power amplifiers at the front end of devices can be effectively handled

Experimental Validation of a Best-Fit Model for Predicting Radio Wave Propagation through Vegetation

In this study, a model for predicting radio wave propagation through vegetation at 900 and 1800MHz is proposed. An integrated model comprising of ground and foliage induced effects is evaluated with respect to experimental data obtained through drive test in and around a vegetation environment, using Test Mobile System (TEMS) investigation tools. Measured path loss was compared against predictions made by four empirical vegetation models. Results indicate that the European Cooperation in Science and Technology (COST) 235 model gives the best prediction and compare favourably with measured path loss in areas where vegetation is dominant. Although, this model showed the most accurate prediction of foliage loss in the investigated area, there is a need to modify it for enhanced signal prediction. The modified model was found to predict the measured path loss with Root Mean Square Errors (RMSEs) of 6.98dB and 10.00dB at 900 and 1800MHz, respectively. Overall, findings revealed that these RMSEs are within the acceptable range of up to 15.00dB, for quality signal prediction in related environment

Capacity Integration into a Microgrid, a Tool for Electrical Energy Supply Cost Reduction in Nigeria- Covenant University as a Case Study

The cost implication of running a cluster of stand-alone power generating plants was investigated using the generating capacities of the generators and consumption (load) profile obtained from a campus based substation. Analysis of the results revealed a lot of unused available capacity within the system which invariably increases the operating cost of power generation within the campus. Integrating the power generators into a microgrid was suggested where there will be a common pool of energy sources and all loads attached to the network. The proposed network model seeks to reduce power plant engagement by integrating the generating power plants into a microgrid system. To overcome the challenge of synchronization in the AC platform as the power generators are dissimilar, the network is designed to operate as a DC microgrid where the AC generating plants and loads will be interfaced by converters (rectifiers) and inverters respectively. This method reduced the unused capacity being wasted by reducing power plant engagement and consequently reducing the running cost of power generation in the campus

Effect of egg sizes on egg qualities, hatchability and initial weight of the hatched-chicks

The study evaluates the relationship of egg weights with other egg qualities, hatchability and hatchling weights. One thousand eight hundred eggs from marshal broiler chicken were categorized into small (50 – 59 g), medium (60 – 69 g) and large (≥70 g) of 600 eggs per group in a completely randomized design. Hundred eggs from each group were subjected to quality analysis and the remaining incubated for hatchlings production. The egg length of of large group was the highest (4.71 cm) and lowest in small (4.22 cm). The relationship revealed 32.86% yolk in small size, while 33.71 and 30.99% was observed for medium and large respectively. Also, albumen ranged from 50.85% in small to 55.38% in large. Hatchability result revealed 74.50% for small egg and reduced as sizes increased. Hatchling weight was highest in large (49.19 g) and lowest in small (38.79 g). The regression equations showed that albumen weight and egg size were best predictors of chick's weight through their R2 values (0.68 and 0.57 respectively) compared to yolk weight with R2 of 0.28. It was therefore be inferred that breeder eggs size could affect egg quality parameters and chick's weight

Determinants of skilled care utilization among pregnant women residents in an urban community in Kwara State, Northcentral Nigeria

Background: Skilled attendant at delivery (SBA) is one of the key indicators used in assessing progress towards improved maternal health. This study aimed at identifying factors influencing SBA utilization in Ilorin, Nigeria.Methods: This cross-sectional study was carried out using multi-stage sampling technique among 400 participants in Ilorin, Northcentral Nigeria. A pre-tested questionnaire was used for data collection, and data analysis was done using descriptive and inferential statistics.Results: SBA supervised 73.8% births. Determinants of skilled birth attendance at delivery include higher education (AOR; 10.94, 95% CI; 3.60-33.26), having only one child (AOR; 4.33, 95% CI; 1.18-15.82), having at least 4 ANC attendance (AOR; 18.84, 95% CI; 8.95-55.82) and residing near delivery sites (AOR; 11.49, 95% CI; 2.43-55.56).Conclusion: The proportion of births supervised by SBA needs improvement in Northcentral Nigeria. Full implementation of reproductive health policies will enhance skilled births in Nigeria.Keywords: Skilled birth attendants, Antenatal care, utilizatio

CORROSION PERFORMANCE OF 1014 MILD AND 304 STAINLESS STEELS IN ACIDIC MEDIA

Corrosion is a degradation of metallic materials under the action of the environment which requires oxygen and moisture to occur. This research work determined the corrosion performance of 1014 low carbon and 304 austenitic stainless steels in different concentration of acidic media. Corrosion tests were carried out using gravimetric technique. One hundred and eighty samples of the metals were prepared and immersed in containers of sulphuric acid (H2SO4), hydrochloric acid (HCl) and nitric acid (HNO3) at 1, 2 & 3 M. The samples were then removed every three days for a period of 15 days to measure the weight loss. These were used to calculate the corrosion rates. The chemical analysis was determined using an Energy Dispersive X-ray (EDX).  Scanning Electron Microscope (SEM) was used to determine the texture of the samples. The results showed that the corroded samples had pitting corrosion damage and cracks propagated generally on the sample surfaces. The corrosion rates of the samples increased with increase in molarities of the reagents, Stainless steel samples had the least corroded surfaces. The study concluded that the higher the level of concentration of acidic media (1 to 3 M), the higher the corrosion rates of samples in increasing order of HNO3, HCl and H2SO4 especially for mild steel sample (4.35 to 17.90, 0.21 to 2.90 and 10.37 to 0.64 mm/y) after 360 hours of immersion respectively. &nbsp

Knowledge of and Attitude Towards Epilepsy Among Women in Ile-Ife, Nigeria

Background: Epilepsy is a non-contagious chronic disease with sufferers experiencing embarrassments amidst other challenges. Family caregivers are mainly women with some of them suffering from the disease. This study assessed the knowledge and attitude of women residents in an urban community towards epilepsy. Materials and methods: This descriptive cross-sectional study recruited 400 randomly selected women in Ile-Ife. The data was collected with the use of a pre-tested interviewer-administered questionnaire on knowledge of and attitude to epilepsy. Data was analysed using descriptive and inferential statistics. Results: Most respondents (99.3%) were aware of the disease with their main sources of information from their parents, friends, and neighbours. Only 15.3% of respondents had good knowledge of epilepsy, while 35% had positive attitude to epilepsy. Factors associated with good knowledge of epilepsy among respondents include having higher education (OR = 3.154, 95%CI = 1.574–6.323, p = 0.001) and higher income (OR = 3.055, 95%CI = 1.404–6.651, p = 0.005), while factors associated with positive attitude towards epilepsy include older age group (OR = 1.943, 95%CI = 1.281–2.945,p = 0.002) and higher income (OR = 2.932, 95%CI = 1.345–6.386, p = 0.007). Conclusions: Although the level of awareness is high, respondents’ knowledgeand attitude were inadequate. There is a need for a community education about epilepsy, targeting women who are major stakeholders with the aim of improving their knowledge and attitude towards the disease

Direct bioleaching of Zinc using manihot esculenta crantz (cassava) extract without additives

Abstract: The advent and development of new technologies that will provide better yields, cleaner and a safer environment is a global challenge for the researchers. Traditional solvents used in extraction of minerals are at many times hazardous thereby constituting threats to the ecology. The work reports the direct bioleaching of zinc sourced from Abakaliki-Ishiagwu complex zinc sulphide ore deposit. The sphalerite ore is predominant in Zn with other associated metals Pb, Cu, Fe, Ni, Sb, As, Cd, Au, V, Co, Ag, K, Al and Ca. It covers the pre extraction processes of mineral comminution (crushing and grinding); separation by froth flotation; and roasting. Agro-cyanide was extracted from cassava plant (Manihot esculenta Crantz) leaves and was used as leachant without any additive. The result of atomic absorption spectrometry (AAS) analysis of the leached liquor (pregnant solution) shows that lead, copper and iron in addition to Zinc, were obtained from the leached ore roast at 149.25 ppm (Zn), 79.25 ppm (Pb), 0.25 ppm (Cu) and 4.25 ppm (Fe) extraction after 21 days. Elongated contact of ZnO ore is not encouraging for Zn extraction as there is a decline in the quantity of Zn, Fe and Cu as the leaching time (days) increases. The mechanism of the Leach next faction is yet to be fully ascertained, hence the need for further work in the area