Equal Channel Angular Extrusion Characteristics on Mechanical Behavior of Aluminum Alloy

Materials strengthened by conventional methods such as strain hardening, solute additions, precipitation and grain size refinement are often adopted in industrial processes. But there is limitation to the amount of deformation that these conventional methods can impact to a material. This study focused on the review of major mechanical properties of aluminum alloys in the presence of an ultrafine grain size into polycrystalline materials by subjecting the metal to an intense plastic straining through simple shear without any corresponding change in the cross-sectional dimensions of the sample. The effect of the heavy strain rate on the microstructure of aluminum alloys was in refinement of the coarse grains into ultrafine grain size by introducing a high density of dislocations and subsequently re-arranging the dislocations to form an array of grain boundaries. Hence, this investigation is aimed at gathering contributions on the influence of equal channel angular extrusion toward improving the mechanical properties of the aluminum alloys through intense plastic strain

Qualitative Assessment of Effects of Encroachment on Water Resources of Agba Dam, Ilorin Nigeria

The city of Ilorin in Nigeria has experienced high population growth and rapid urbanization. Agba Dam is one of the major sources of potable water in Ilorin, and currently been threatened by anthropogenic induced encroachment activities, with potential for significant derogatory effects on its quality. Therefore, this paper assesses the qualitative impact of encroachment on the water resources regime of Agba Dam, Ilorin, Nigeria. Field survey was carried out to scope proximal anthropogenic activities and to delineate historical and current extent of the encroachment area of the dam. Representative water samples were collected from locations within the dam catchment, and subsequently analyzed for alkalinity, dissolved carbondioxide, chloride, total iron, copper, sulphate, colour, calcium, dissolved oxygen and turbidity. In addition, historical physical and chemical data of water samples obtained from the dam were also acquired, and analyzed to determine temporal variation in the quality. The results show a reduction of 0.89 km2 or 63% in the historical buffer boundary of the dam. The values of the measured physico-chemical parameters were generally similar to that obtained for the historical values and therefore suggest limited impact of the anthropogenic activities on the water quality. However, slight increases were observed in the measured concentrations of the alkalinity, dissolved carbondioxide, chloride, iron, copper and sulphate, and this indicates possibilities of water quality alteration, with potential consequences for ecosystem and aquatic life if the trend is unabated. Keywords: Anthropogenic, Water quality, Agba dam, Ilorin Nigeri

Material Selection for Gas Turbine Blade Coating Using GRANTA Material Selector

This paper presents the selection of suitable candidate materials for thermal barrier coating of gas turbine blade using GRANTA software. There have been reported cases of gas turbine blade failure in service due to the extreme service conditions. Such failure could possibly have occurred due to poor material selection for thermal barrier coatings on the turbine blade thereby exposing the blade to harsh condition over time. The major adverse effects on these blades are thermal fatigue, high temperature oxidation, hot corrosion, interdiffusion, high cycle fatigue and creep

Impact of activated–flux tungsten inert gas (a-tig) welding on weld joint of a metal – Review

Welding is applied in every industry and it’s a major method of manufacturing and revamping metal products because its generally economical, efficient and reliable as a means of joining together metals. Various ways have been proposed to improve the process ranging from adjusting the various welding parameters like welding current, voltage, arc length, width, type of shielding gas used, to using arc pulsing. The method that has however gained the most attention is the Activated-flux TIG welding process which utilizes welding flux to help reduce the bead width and increase the weld penetration. In order to improve the TIG welding process’s industrial efficiency and penetration ability, one method commonly applied is the use of activating flux with the welding process. This review provides insight to the impact of Activated - Flux Tungsten Inert Gas Welding on weld joint of a materials metal

Radiation Effects: Recommendations for Safe Plasma/Flame Cutting Operation

Plasma cutting has been a revolutionary method of processing metals as it provides precision cutting with a smooth finish. The Plasma Arc Cutting machine is an important machine used for producing fine cuts and creating shapes in materials. In addition to high energy radiation (ultraviolet and visible) which plasma arc cutting generates, the intense heat of the arc also generates substantial quantities of fumes and smoke from vaporizing metal in the kerf. With a reflection on a case study, this paper examines the working processes of the machine and the effect on the health of operators or any unsuspecting member of the public. With the safety regulations and recommendations from certified bodies, recommendations are made to ensure safety and limitations of health hazards during the use of the machine

Morphological characterization and physio-chemical properties of nanoparticle - review

The discovery by researchers that the physio-chemical properties of a substance can be influenced by size led to a realization of the importance of Nano particles. Due to its excellent characteristics, these materials have been a source of interest for researchers in multidisciplinary fields. The morphological features of nanoparticles always garner prodigious attention because of the influence morphology has over most of the Nanoparticles’ properties. This review provides insight to the morphological characterization and physio-chemical of its properties

The Challenges and Panaceas to Power Distribution Losses in Nigeria

Energy losses in the distribution network and its subsystems have been issues of great concerns in Nigeria’s power sector. For decades, several studies have been conducted on the challenges facing the power sector in Nigeria with most focus directed on the distribution subsystems. The major challenge in the distribution system is the high energy losses which are detrimental to the techno-economic benefits of the power systems. However, details of the distribution system challenges and the probable solutions have not been efficiently presented. In this study, some of these challenges are presented and the potential solutions are proposed. The features of the Nigeria distribution network, the technical and non-technical sources of losses as well as the identified challenges are presented before discussing the potential solutions. The panaceas so provided were from the understanding of some published works and other related materials as well as the in-depth understanding of the authors. This article can serve as a guide for the utilities and stakeholders in the power sector for efficient management operations and improved customer service delivery

Screening for diabetes mellitus in a Nigerian family practice population

Background Diabetes mellitus is a non-communicable disease with a rising prevalence worldwide. Most of the increase in prevalence is projected to be in the developing countries. As it is recognised that the onset of the disease and its complications predate the symptoms, it is expedient that screening procedures are undertaken to diagnose the disease in the individual as early as possible to minimise the risk of complications. Diabetes mellitus is a chronic disease necessitating life-long therapy, usually with drugs. This creates a life-long financial burden on the family, especially in low socio-economic communities in West Africa, where the majority of the population still lives on less than one dollar a day. This affects the wellbeing of the entire family, hence the need for early detection, prompt and adequate management of the disease and avoidance of its complications. Methods The study is an incidental screening to determine the prevalence of diabetes mellitus, its risk factors and the clinical characteristics of diabetics in a Nigerian family practice population. Four hundred and twenty subjects aged 15 years or older were recruited by systematic random sampling in a family practice in South West Nigeria over a three-month period. Data collected include the subjects\' socio-demographic data, family history of diabetes mellitus and hypertension, and history of tobacco and alcohol use. The subjects\' weight and height were measured and their body mass index (BMI) calculated. Each subject was examined for peripheral neuropathy, lens opacity and hypertension. Fasting blood glucose was measured using a glucometer and urine was tested for albumin. Those with a fasting blood glucose of greater than 6.1 had a fasting blood glucose determination by the standard spectrophotometric method. Results Ten (2.38%) subjects were known diabetics, while 57 (13.6%) were known hypertensives. Ten (2.38%) new diabetics were identified, and 7.5% of the females compared to 5.8% of the males were diabetic. Alcohol intake, obesity, age above 44 years and a positive parental history of diabetes were the significant risk factors (p < 0.01) for diabetes in the study. Proteinuria and peripheral neuropathy were the significant complications (p < 0.01). Conclusions It is concluded that diabetes is a common problem in our practice, with a prevalence of 4.76%, half of which was previously undiagnosed. Alcohol intake, obesity, positive parental history and age over 44 years were the identified risk factors. Peripheral neuropathy, proteinuria and high blood pressure were the identified complications. It is recommended that routine screening of people at high risk of diabetes mellitus in family practice be commenced. The glucometer, a relatively cheap item of equipment in the practice, is a highly useful, sensitive and specific tool for this purpose. South African Family Practice Vol. 49 (8) 2007: pp. 1

ASSESSMENT OF IN-TRICYCLE EXPOSURE TO CARBON MONOXIDE EMISSION ON ROADS IN NIGERIAN URBAN CENTRES

This research project investigates in-tricycle exposure to carbon monoxide emission on roads in Nigerian urban centres. Pollution was discussed with air pollution as priority, carbon monoxide a criteria air pollutant was used as case study. The minor and adverse effects of carbon monoxide exposure were buttressed, including its sources, majorly from incomplete combustion of fuel in automobile. This research displays a basic audit of overall research work led to portray CO exposure inside tricycles. Specific sampling roads were selected in urban areas, majorly areas with high traffic congestion, measurement methods for field testing are exhibited alongside levels of exposure of the passengers to the measured carbon monoxide. Using the results obtained from this research statistical and graphical analysis were carried out, five out of the six sampling routes were identified to have concentrations that exceed standards of environmental and regulatory bodies. Governmental and environmental limits for carbon monoxide, range between the values of 9-10ppm. The control road showed an ideal in-tricycle carbon monoxide level due to less traffic, therefore was considered safe. This research also proved that the level of exposure to carbon monoxide on roads is relative to the extent of traffic congestion. Extrapolation was carried out to obtain 8- hour and 24-hour averaging periods to determine the exposure level over time, even if the traffic disperses, the out of the six roads still showed high concentration values after 8 hours and 24 hours. This research proved that passengers are exposed to carbon monoxide in tricycles. The level of exposure can also be present in concentrationsenough to harm the health of passengers. Recommendations were made to help reduce high carbon monoxide concentrations in tricycles

Effect of TiC addition on the mechanical properties and microstructure of Al-Si alloy

This study is focused on the development and characterization of a stir cast Al-Si alloy reinforced with titanium carbide nano-particles. The composite was developed using the stir casting method and the casted samples were prepared with TiC nano-particle at 0.4 (B1), 0.8 (B2), 1.2 (B3), 1.6 (B4) and 2.0 (B5) wt. % of the entire composition, as well as a control sample, and thereafter subjected to tensile and hardness tests. It was noticed that none of the samples at the chosen concentrations brought about a greater hardness value than that of the control sample (Sample A), however they all show a positive trend with an increase in the % wt. of reinforcement bringing about a possibility of increase in the hardness value. This suggests that a further increase above 2.0% of the reinforcement should bring about an increase in hardness above that of the base Al-Si alloy. On the other hand, the tensile strength was significantly increased upon reinforcement. B5 exhibited the highest tensile strength by displaying a transition from needles/plate-like to globular/fibrous morphology