Browsing by Author "Aremo, Bolaji"
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- ItemOpen AccessAdverbial-Tense Relationships in the Written English of Selected University of Ife Students.(Obafemi Awolowo University, 1986) Fabusuyi, Mojisola Ajibike; Aremo, BolajiAdverbial-tense relationships are an important area of English grammar. It is indeed generally felt that there is the need for learners of English as a second language to master these relationships adequately if they must use the language for effective communication. The present study is an attempt at examining the mastery of the relationships by Nigerian learners and users of English. It would seem clear from the findings that, compared with native speakers, the Nigerian students selected for the study were grossly deficient in their adverbial-tense usage. Thus, it was found that of the 48 temporal meanings identified by David Crystal in a study on adverbial-tense relationships in native English, only 18 were expressed by the students. In the light of the findings, suggestions are made for improvement in the teaching of the relevant areas of English to Nigerian students.
- ItemOpen AccessDesign and Construction of a Vacuum Casting Equipment for Aluminium Alloys(2015-06-19) Aremo, BolajiThis work reports the design and construction of an apparatus for the vacuum casting of aluminium alloys, production of cast components using the apparatus and evaluation and comparison of the quality of cast components produced by vacuum casting. This is with a view to alleviating the problems of poor castability and produce inclusions-free castings. Melting and vacuum requirements of the equipment were determined based on a furnace capacity of 15 kg of aluminium. The heating power requirement was calculated for this mass while refractory requirements necessary for a 15 kg mass and non-slagging application was determined. Low-cost clay-based refractory and insulating bricks were specifically developed from locally-available raw materials and novel production routes were used for their production. The vacuum system was made from locally available materials designed for optimal efficiency required for vacuum casting. Computer Aided Design software was integrated into both sheet metal forming and refractory mould design. The equipment was used to melt and cast small-sized specimens using the lost-wax technique and compared with green sand and ceramic mould cast specimens. Tensile and shrinkage tests and microstructural examination were carried out on all specimens. The results of the tensile strength of the vacuum cast, green sand cast and ceramic mould cast specimens of the aluminium alloy were 123.23, 98.83 and 113.56 MPa respectively. Furthermore, shrinkage defect which was common to both green sand and ceramic mould casting was eliminated in vacuum casting. The continual replenishment of the mould cavity by molten metal from the furnace effectively eliminates shrinkage in the cast component during vacuum casting. In conclusion, the aluminium alloys cast from the designed and constructed vacuum casting apparatus showed improved properties when compared with those from the traditional green sand and ceramic mould.