NUMERICAL SIMULATION OF OUTER DIE ANGLE OF EQUAL CHANNEL ANGULAR EXTRUSION PROCESS

The study of the simulation of effect of outer die angle in Equal Channel Angular Extrusion (ECAE) process was investigated. The simulation was carried out on 6063 aluminium alloy with a view to achieve ultra-fine grain structures. ADINA user interphase Version 8.6 (900 modes) was used for the simulation. The unextruded parameters of the 6063 aluminium alloy were used as input codes and some basic assumptions were made in designing the model on 2-Dimensional scale. The billet was meshed by dividing the vertical and horizontal geometry into 30 and 4 elements respectively. The die angle was varied from 0o to 90o and the simulation results were displayed. The results showed that the force of 27.5X106 N, 27.5X106 N, 27.6X106 N and 31.2 X106 N was required to deform when the outer die angle was 0o, 22.5o, 45o and 90o respectively. Also, the strains achieved were 0.61, 0.62, 0.66 and 0.69 respectively. Thus, highest force is required at 90o and the strain achieved at 0o is the lowest. Based on the results, it was recommended that it is more economical to extrude at an outer angle between 22.5o and 45o as a relatively higher effective strain will be induced

NUMERICAL SIMULATION OF OUTER DIE ANGLE OF EQUAL CHANNEL ANGULAR EXTRUSION PROCESS

The study of the simulation of effect of outer die angle in Equal Channel Angular Extrusion (ECAE) process was investigated. The simulation was carried out on 6063 aluminium alloy with a view to achieve ultra-fine grain structures. ADINA user interphase Version 8.6 (900 modes) was used for the simulation. The unextruded parameters of the 6063 aluminium alloy were used as input codes and some basic assumptions were made in designing the model on 2-Dimensional scale. The billet was meshed by dividing the vertical and horizontal geometry into 30 and 4 elements respectively. The die angle was varied from 0o to 90o and the simulation results were displayed. The results showed that the force of 27.5X106 N, 27.5X106 N, 27.6X106 N and 31.2 X106 N was required to deform when the outer die angle was 0o , 22.5o , 45o and 90o respectively. Also, the strains achieved were 0.61, 0.62, 0.66 and 0.69 respectively. Thus, highest force is required at 90o and the strain achieved at 0o is the lowest. Based on the results, it was recommended that it is more economical to extrude at an outer angle between 22.5o and 45o as a relatively higher effective strain will be induced

Mathematical Modelling of Aluminiun Surface when Dipped in Molten Metal

A mathematical model is presented to describe the undulating surface of aluminium casting during an industrial process involving the dipping of the mould, at a particular velocity, into the molten metal. The problem of air gap formation between the mould and the casting was also considered. Below certain value of the mould velocity the shape of the casting as well as its thickness remain practically unchanged with changes in mould velocities. The undulating surface disappears when the mould temperature is in excess of 120oC. (Nigeria Journal of Pure and Applied Physics: 2003 2 (1): 36-39

Study of Surface Modification of Electrospun Polyethylene Oxide Composite Fibre

Functionalization of polymers had gained attention because of advance applications as sensor, energy devices, membrane, etc. This present study is aimed at studying surface modification as a result of electrospinning functionalized polyethylene oxide (PEO) with zinc ion Zinc chloride was added in various proportions to PEO solution then electrospun at various voltage. Fibres resulted into various shapes; belt, rod, mat and thread which differs from the primary PEO. The mechanism for the morphology modification was studied and the optimum conditions which retain the fibrous morphology were noted. This functionalized PEO can be used as energy device. Keyword: Polyethylene oxide, Modification, Fibre, Composite, Functionalize

Re-usable low density polyethylene arm glove for puerperal intrauterine exploration

Objective: To design a long arm glove that can be used within a puerperal uterus to prevent the health-care worker contracting HIV from an infected patient. The designed long arm glove should be cheap (affordable) and readily available in low resource centres and must have proven sterilityassurance and tensile strength to confer protection for the health worker.Design: Prospective study.Setting: Obafemi Awolowo University Teaching Hospitals Complex, Ile-Ife, Nigeria from 1st December 2006 to 31st May, 2007.Subjects: Fifty medical students of both sexes were selected randomly and the average length from the styloid process to the mid upper-arm of each was measured and the average length was later determined. This was to determine the length of the low density polyethylene long arm gloves tobe made from virgin polyethylene material. Consecutive cases of patients with retained placentae in the puerperium who were scheduled for manual removal of the placenta within the period.Results: Packs of low density polyethylene (LDPE ) long arm gloves were made from virgin polyethylene material. When subjected to bacteriological analysis, three out of four glove packs were contaminated with Staphylococcus, Bacillus and Klebsiella species of bacteria. Gamma irradiation ranging from 28.133 to 83.35 kiloGray of gamma-irradiation (kGy) sterilised all the gloves as postirradiation glove specimens showed no bacterial contamination. However, at doses up to 50 kGy gamma irradiation caused “strengthening” of the polyethylene gloves. While at doses greaterthan 50 kGy, gamma irradiation caused “embrittlement” of the material. Thus, 50 kGy of gamma irradiation was found to be an ideal dose to strengthen and to sterilise the glove for usage. The sterilized gloves were found to be effective when used in consecutive cases of retained placentain protecting the health care workers (HCW) from contamination by possibly HIV contaminated blood.Conclusion: There is a risk of contracting HIV for the health-care worker while carrying out a procedure within the puerperal uterus. The low density polyethylene arm glove was designed to prevent this in low resource centres as it would be affordable, available, with proven sterility assurance and mechanical properties to confer protection for the healthcare worker