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Search Results: 1 - 10 of 260648 matches for " G. I. Lawal "
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Adaptable Technologies for Life – Cycle Processing of Tantalum Bearing Minerals  [PDF]
M. O. H. Amuda, D. E. Esezobor, G. I. Lawal
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2007, DOI: 10.4236/jmmce.2007.61006
Abstract: Nigeria is richly endowed in convertible natural resources of which solid minerals are a member of the endowments. However, the country is basically a mono-product economy based on its vast oil deposit accounting for over 84% of foreign earnings and 25% of GDP. The triple challenges of the volatile nature of global oil politics, achieving the objectives of the millennium development goals and the national economy empowerment and development strategies calls for diversification into hitherto neglected solid mineral deposits to open a window of opportunities. One of the widely reported mineral deposits in the country with strong international influence is tantalum-bearing mineral. The mineral had in the past few decades experienced a strong growth in demand averaging 10% per annum since 1992 with total world consumption estimated at over 38 thousand tonne in 2005. The total annual supply of the ore concentrate in 2001 was 720 tonnes when demand was 26 thousand tonnes. Thus, pushing the price of the concentrate to an all time high of $165 / kg in 2001. This paper outlines the characteristics of the Nigerian tantalum reserves. It also presents the evaluation of the competing technologies for complete cycle processing of tantalum bearing minerals for adoption in the Nigeria solid mineral industry.
Review of Green Polymer Nanocomposites  [PDF]
Samson O. Adeosun, G. I. Lawal, Sambo A. Balogun, Emmanuel I. Akpan
Journal of Minerals and Materials Characterization and Engineering (JMMCE) , 2012, DOI: 10.4236/jmmce.2012.114028
Abstract: Recently, attention has been drawn to the use of bio-reinforced composites in automotive, construction, packaging and medical applications due to increased concern for environmental sustainability. Green polymer nanocomposites show unique properties of combining the advantages of natural fillers and organic polymers. Plant fibers are found suitable to reinforce polymers. They have relatively high strength and stiffness, low cost of acquisition, low density and produce low CO2 emission. They are also biodegradable and are annually renewable compared to other fibrous materials. Organic polymers on the other hand, are desirable because they are either recyclable or biodegradable without causing environmental hazards. This paper reviews current research efforts, techniques of production, trends, challenges and prospects in the field of green nanocomposites.
Mechanical Response of Al-1.09Mg2Si Alloy under Varying Mould and Thermal Ageing Conditions
O. I. Sekunowo,G. I. Lawal,S. O. Adeosun
Journal of Metallurgy , 2012, DOI: 10.1155/2012/921235
Abstract:
Mechanical Response of Al-1.09Mg2Si Alloy under Varying Mould and Thermal Ageing Conditions
O. I. Sekunowo,G. I. Lawal,S. O. Adeosun
Journal of Metallurgy , 2012, DOI: 10.1155/2012/921235
Abstract: Samples of the 6063 (Al-1.09Mg2Si) alloy ingot were melted in a crucible furnace and cast in metal and sand moulds, respectively. Standard tensile, hardness, and microstructural test specimens were prepared from cast samples, solution treated at 520°C, soaked for 6?hrs, and immediately quenched at ambient temperature in a trough containing water to assume a supersaturated structure. The quenched specimens were then thermally aged at 175°C for 3–7?hrs. Results show that at different ageing time, varied fractions of precipitates and intermetallics evolved in the specimens’ matrices which affect the resulting mechanical properties. The metal mould specimens aged for four hours (MTA-4) exhibited superior ultimate tensile strength of 247.8?MPa; microhardness, 68.5?HV; elongation, 28.2% . It is concluded that the extent of improvement in mechanical properties depends on the fractions, coherence, and distribution of precipitates along with the type of intermetallics developed in the alloy during ageing process. 1. Introduction Casting is one of the most versatile methods of producing structural aluminium alloy components. However, the rather large preponderance of defects in cast aluminium components often limits their performance and adversely impacts their commercial values. Hence there is the need for a novel processing approach to improve the cast microstructure for enhanced performance. Generally, the poor mechanical properties of cast aluminium alloys can be improved through either alloy addition or various forms of heat treatment [1]. During the heat treatment of cast aluminium alloys, an advantage is made of the characteristic decrease in solubility at low temperature of magnesium (Mg) and silicon (Si) which are the main alloying elements in Al-Mg-Si alloy. Further, Keist [2] confirms that the appreciable decrease in concentration of the alloying elements at room temperature is the fundamental phenomenon that provides the basis for increasing substantially the hardness and strength of aluminium alloys through isothermal treatment. Similarly, Siddiqui et al. [3] have shown that improved ductility can be achieved by process annealing at 415°C, soaked between two and three hours coupled with a cooling rate 30°C per hour. Generally, strength improvement of most 6063 aluminium alloys can be effected in a three-pronged approach comprising solution heat treatment, quenching, and precipitation of solute atoms [4]. However, the greatest challenge usually encountered with this approach is effective control of the second-phase precipitates. Lumley et al. [5]
A Survey for Biting Flies in three Local Government Areas of Taraba State, Nigeria
SN Karshima, I Ajogi, G Mohammed, AI Lawal
Sokoto Journal of Veterinary Sciences , 2011,
Abstract: This study was carried out to determine the prevalence of biting flies from Gashaka, Ibi and Karim Lamido Local Government Areas (LGA) of Taraba State between July and August, 2010 using biconical traps, and identify them using morphological characteristics. Of the 908 biting flies collected from the traps 37.9% (344/908) were Tabanus, 25.9% (235/908) were Haematopota, 24.5% (223/908) were Chrysops, and 11.7% (106/908) were Glossina. Based on the LGAs sampled, the distribution of the flies in Gashaka, Ibi, and Karim Lamido (K/Lamido) were 44.6% (419/908), 21.9% (199/908), and 33.5% (290/908) respectively (p<0.05). An infection rate of 1.89% (2/106) was observed among the tsetse flies trapped. Two species of tsetse flies were identified as Glossina palpalis representing 67.9% (72/106) and Glossina tachinoides 32.1% (34/106). In conclusion, Tabanids had the highest distribution while Glossina had the lowest distribution across the three (3) LGAs of the State.
The level of awareness of Human African Trypanosomosis (HAT) in Taraba state, Nigeria
SN Karshima, I Ajogi, G Mohammed, AI Lawal
Sokoto Journal of Veterinary Sciences , 2010,
Abstract:
Anti-retroviral therapy induced diabetes in a Nigerian
A G Bakari, F Sani-Bello, M S Shehu, A Mai, I S Aliyu, I I Lawal
African Health Sciences , 2007,
Abstract: Background:Anti-retroviral therapy (ART) using Highly Active Anti-retroviral Therapy (HAART) has led to considerable reduction in morbidity and mortality associated with human Immune deficiency virus (HIV) infection.This has led to increased life expectancy in HIV infected individuals on one hand, and side effects of chronic administration of these drugs on the other. One of such untoward effects is the association of anti-retroviral drugs especially the protease inhibitors (PI\'s) with metabolic derangements such as dyslipidaemia, lipodystrophy, insulin resistance and rarely Diabetes mellitus. Although there is extensive literature on this dysmetabolic syndrome in the Western World; there is to our knowledge no previous report from Nigeria. Objective: to report a case of diabetes mellitus following the initiation of anti-retroviral therapy. Methods: a case report of diabetes mellitus induced by anti-retroviral therapy in a 48 year old Nigerian male. Conclusion: Awareness and high index of suspicion is required to identify the metabolic complications of ART.
Reactive airway and anaesthesia: challenge to the anaesthetist and the way forward
I Lawal, AG Bakari
African Health Sciences , 2009,
Abstract: Background: Patients with concurrent medical conditions such as Reactive airway disease presenting for anaesthesia, and surgery have potentially increased risk of perioperative morbidity and mortality if not well managed. Objective: To highlight the need for adequate perioperative care and review the evidence for selection of techniques in the anesthesia for such cases Materials and methods: An illustrative case is presented. Conclusion: The main goal of the anaesthetist is to administer safe and sufficient anaestheia without precipitating bronchospasm. Keyword: Reactive airway, anaesthesia, presentation, management and constraints. African Health Sciences 2009; 9(3): 167-169
Serum Proteins, Thyroid Hormones and Alkaline Phosphatase Concentrationsin Acute Experimental Trypanosoma congolense Infection in Yankasa Sheep Immunomodulated with Levamisole
M. Bisalla,K.A.N. Esievo,N.D.G. Ibrahim,I.A. Lawal
Journal of Animal and Veterinary Advances , 2012,
Abstract: Serum proteins, thyroid hormones and alkaline phosphatase concentrations were measured in Yankasa sheep experimentally infected with T. congolense. Parasitemia occurred in the T. congolense infected sheep immunomodulated with levamisole two days earlier than the infected group without immunodulation.Packed cell volume decreased significantly(p< 0.05) in the infected groups with and without immunomodulation when compared to the controls from the first week of infection up to the end of the experiment. Serum total protein, albumin, Thyroxine (T4) and Triiodothyronine (T3) decreased significantly (p< 0.05) in the infected sheep with and without immunodulation when compared to the controls. Serum Thyrotopin (TSH) and Alkaline Phosphate (AP) did not alter significantly (p>0.05) in the infected sheep with and without immunomodulation when compared to the controls throughout the period of the experiment. In general, levamisole administration did not appear to alter the infection when compared to the infected group without immunomodulation.
Gas Phase Electroformation of Polypyrrole
A.T. Lawal,G.G. Wallace
Journal of Applied Sciences , 2008,
Abstract: Gas phase electrochemical polymerization of pyrrole was investigated in which platinum electrode coated with Nafion dopant was exposed to pyrrole vapour. Homogeneous and thin conductive films were uniformly fabricated at nano level thickness. The polypyrrole obtained were characterized by cyclic voltammetry. Experimental parameters such as the Nafion concentration, polymerization time and current density were investigated. The parametric study has been investigated in order to synthesize homogeneous film in a reproductive manner.
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