60 research outputs found

    Anterior bilateral temporomandibular joint dislocation: an emergency presentation

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    Anterior dislocation of the temporomandibular joint (TMJ) though an infrequent presentation at the emergency department; often demands an immediate reduction to relieve discomfort and prevent adverse long-term sequelae. A simple and effective technique to reduce the dislocation is successfully demonstrated by putting the operator\u27s thumbs over the molar teeth of the patient and pushing the dislocated jaw downward and backward. We report the case of a patient who presented at our accident and emergency department with bilateral anterior TMJ dislocation and was successfully reduced with this simple technique

    Effect of Weed Control Methods and Canopy Characteristics on Weed Biomass, Yield and Yield Components of Two Contrasting Cassava Varieties in the Rainforest Zone of Nigeria

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    Weed infestation is one of the reasons why the average cassava yield is low in Nigeria. This study was conducted in 2010 at the Teaching and Research Farm, Obafemi Awolowo University, Ile-Ife to evaluate the impact of different cassava canopy structures on (i) weed biomass and (ii) yield and its components. The treatments consist of hand-weeded, herbicidal treatment, and unweeded checks in the main plot. The sub-plots constituted the cassava cultivars (TMS 30572 and TME 1) laid out in a randomized complete block with a split-plot arrangement in three replications. TMS 30572 reduced weed biomass by 59% when compared to TME 1 in the unweeded plot. However, there was no significant difference in the weed biomass between the hand-weeded and herbicide-treated where TMS 30572 and TME 1 were cultivated. Root dry matter of TMS 30572 was higher by 72% when compared to TME 1 in the untreated field. However, there was no significant difference between the yield of TMS 30572 and TME 1 in both hand-weeded and herbicide-treated plots. In conclusion, TME 30572 is recommended for cultivation in regions with similar agroecological patterns coupled with Integrated Weed Management (IWM) especially, when planting TME 1 to obtain optimum yield. Keywords: Weed biomass, TMS 30572, TME 1, Yield, and Integrated Weed Management. DOI: 10.7176/JNSR/12-14-05 Publication date:July 31st 202

    Effect of Coolant Temperature on Machining Characteristics of High Carbon Steel

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    This paper reports on the effect of coolant temperature on machining of high carbon steels. The development of a cooling system to reduce the temperature of water soluble coolant to 7.9oC from ambient temperature was employed in this work to improve the machining performance. The experiments were performed using cooled and ambient temperatures by employing Taguchi L18 orthogonal array to design the experimental runs. The cutting speed, feed rate and depth of cut were the machining parameters used; while the tool-work piece interface temperature was monitored using a digital thermometer with k-type thermocouple wire. The selected control factors are material removal rate and surface roughness. The experimental results were analyzed using Minitab 16. The main effects and percentage contributions of various parameters affecting surface roughness and material removal rate were discussed, and the optimal cutting conditions were determined. It was observed that surface finish improved by 65% with the use of the developed cooled system. The reduction in coolant temperature played a vital role in improving surface finish during machining high carbon steels

    Nigeria’s Phosphate and Uranium Mineral Occurrences: Implication for Mineral Investment

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    The main aim of this paper is to review the occurrences of phosphate and uranium in Nigeria with a view to encourage local and international investors to develop and exploit these deposits. Nigeria is located on latitude 100 North and longitude 80 East surrounded in the north by Niger and Chad and in the east by Cameroun and in the west by Benin Republic. Available data indicated the viability of mineral investment in the Nigerian phosphate and uranium resources. With the current economic reforms and investment incentives in Nigeria, interested investors are highly welcome to take advantage of developing these mineral resources. Keywords: phosphate, uranium, mineral resources, mineral investment, geochemical mappin

    The Effects of Heat Generation on Cutting Tool and Machined Workpiece

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    Metal cutting processes usually cause heat generation at the cutting zone (around the workpiece-tool intersection). The heat generated during these processes may cause different effects on both the workpiece and tool, this in turn may affect the finished product and the general performance of the machined piece. In this study, a review was done on various types of machining conditions available, effects of heat generated on the workpiece and tool, and the approaches adopted to reduce this heat at cutting zones. This study also focuses on the simulation of percentage ratio of heat removal. To handle the simulation, various approaches of heat removal methods were used to get the percentage ratio using the ansys version 19.1 software. It was discovered that heat generation causes two major types of wear on the tool, crater and flank wear, resulting in the reduction of cutting tool life as well as dimensional inaccuracy, surface damage and severe corrosion cases on the workpiece. Various heat reduction methods and coolant application types were as well studied and their merits and demerits were discussed

    Wear characteristics, reduction techniques and its application in automotive parts – A review

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    Wear phenomenon impact the operating efficiency and service life of engineering materials due to the influence of surface interaction at different working conditions. Successive tribological studies on wear-resistant materials in the last decade is estimated at approximately 40 of friction and wear, including laboratory tests. Most locally improvised wear testers in accordance with American Society for Testing and Materials (ASTM) and European (EN) standards, though, achieves 95-97 parametric accuracies with reduced cost, they hardly harmonize degradation and Archard’s coefficients for all possible wear factors, providing little data for simulation of mechanical and chemical wears which are responsible for non-uniform aggregation of wear patterns in practice. Complexities of intermeshing factors which combine to influence the effectiveness of developed test devices span over loads, speeds, temperature, pressures and ambience for various applications. This study highlights the techniques of wear characterization, test standards and wear reduction with emphasis on surface texturing for improved eta/beta phase re-arrangements at low working temperatures in the enhancement of grain contraction during high bias-voltage cathodic substrate multi-phase coating, phosphating during pretreatments using peening techniques, residual stress reduction during cryogenic heat treatments as well as the impact of suitable architectural matrix composite strengthening, microstructures and material reinforcements as suitable factors to influence improved tribological behaviors in materials. Optimal additive manufacturing (AM‐fabricating) techniques with pretreatments, thermal cycling and tempering can engineer enhanced anti-tribocorrrosion in Automotive components
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