Advanced Materials Research Vols. 62-64

Abstract: The paper work is aimed at using Microsoft Visual Basic 6.0 to develop window based design software that combines flexibility with adequate users interface for the design of chain drives as an engineering transmission element. The chain drives considered are of two types; silent and roller. The calculations are programmed either through ‘known torque’ or ‘through guess pitch value’. The design software combines computational with sketch template in a single process to generate the required parameters of the chain drives. The package was tested with a number of case studies and the results obtained were quite satisfactory.

Abstract: This paper demonstrates the possibility of developing skill in producing sound metal casting from a four-cavity die production mould by assessing the riser design criteria and the castings. The assessment takes into account the location of the casting’s hot spots, casting modulus, liquid metal mass in the risers and the principle of directional solidification. The mould flask is oriented in such a way that a riser is placed directly on top of the casting’s hot spots for proper feeding during solidification. The assessment result of casting modulus shows that the feeder modulus Mf = 5.85 x 10-3 M and the casting hot spot modulus Mh = 1.88 x 10-3 M .The assessment result of castings solidification time shows that the castings solidify within 12 seconds while the feeders solidify within 30 seconds. From the assessment results it is observed that the risers hold liquid metal, feed the castings to full solidification and solidify later than the castings which they feed. Examinations at the cross sections of the finished castings revealed the absence of void formation which is a clear indication of effective and functional risers. Thus, the risers have achieved the desired requirement.

Abstract: Sorting of palm nuts from palm fruit cake, a byproduct obtained after palm oil has been extracted from the batch of digested palm fruit, is burdensome especially to small-scale entrepreneurs involved in palm oil processing business in Africa. This paper has triumphed over the perceived difficulties by using the knowledge of processing engineering to design pilot nut/fibre separator that can efficiently and speedily sort out nuts from nut/fibre mesh. Basic design considerations necessary to achieve reliability of the machine are discussed. Performance evaluation data from the machine obtained were related to its industrial correlate and, in particular, the van der Waerden Normal Scores test carried out inclined us to accept, at a p-value of 0.941, the null hypothesis of no significant difference in processing time between the pilot nut/fibre separator and its industrial counterpart.

Abstract: The results of a study into the design for manufacture of a chemical batch reactor for the synthesis of alkyd resin destined for surface-coating production is presented. The procedures for determining the key geometrical parameters of the reactor are explained. This paper presents the application of fertile innovation to the design and development of chemical batch reactor that uses boiler steam in conjunction with heat from efficient wood stove to achieve constant supply of heat, sustained at about 2500C. The design concept is governed by an analytical model developed and which specifies the optimal reactor geometries that would afford efficient heat and mass transfer. Residence time for our reactor is five (5) hours as against eight (8) hours associated with laboratory scale reactors. The performance of the chemical batch reactor during a preliminary test-run was evaluated in terms of the well over 3000C processing temperature achieved and from the result rises hope eternal.

Abstract: Shell and tube heat exchangers in their various construction modifications are probably the most widespread and commonly used basic heat exchanger configuration in the process industries. There are many modifications of the basic configuration which can be used to solve special problems. Baffles serve two functions: Most importantly, they support the tubes in the proper position during assembly and operation and prevent vibration of the tubes caused by flow-induced eddies, and secondly, they guide the shell-side flow back and forth across the tube field, increasing the velocity and the heat transfer coefficient. The objective of this paper is to find the baffle spacing at fixed baffle cut that will give us the optimal values for the overall heat transfer coefficient. To do this Microsoft Excel 2003 package was employed. The results obtained from previous studies showed that to obtain optimal values for the overall heat transfer coefficient for the shell and tube heat exchangers a baffle cut of 20 to 25 percent of the diameter is common and the maximum spacing depends on how much support the tubes need. This was used to validate the results obtained from this study.

Abstract: This paper focuses on the design of a sub-press mould mounted on a 100-Tonne hydraulic press during compression moulding of composite materials manufacturing process. The sub-press consisting of platens, punch and mould, and guide columns were designed using Microsoft Visual Basic software to minimize time wastages in trail-and-error procedures and mould modifications resulting after the mould is manufactured. Graphical representations of variables which were used in the design such as: platen thickness, guide pin dimensions, clamping force, heat supply, heat losses, and heating element were obtained. The program developed was tested on a solved example in a standard textbook and the result obtained compared well with the result in the book.

Abstract: Hand tools sold in Nigeria have become increasingly unreliable due to critical failures during use. The objective of this study is to test samples of these tools vis-à-vis manufacturer’s claims. A total of fifteen (15) hand tools from six (6) different countries available on the Nigerian market were tested for their quality characteristics. The tested tools included spanners, hammers, screwdrivers, pliers and chisels. Three samples of each of the groups of hand tools were ranked in accordance to their impact energy which is a major property of percussion tools. The results showed that built-in mechanical properties of these hand tools were largely controlled by their alloying elements, manufacturing processes and heat-treatment. Five (5) of the fifteen (15) selected hand tools conformed to BS 876, 1981 and were adjudged safe and reliable.

Abstract: A low cost heat-conserving stove that uses palm waste briquette (substitute for fuel wood) has been developed. It has a furnace size of 400mm diameter and a height of 400mm with a 90mm inner cylindrical burner. The heating surface of the stove generated about 966 kilojoules of heat. A natural draught of 6m/s (efflux velocity) was used to determine the chimney size. The stove which was designed and fabricated mostly from 3mm low carbon steel (mild steel) material can accommodate different sizes of briquette for both domestic and industrial cooking. The air inlet has a regulating duct that controls the burning of the briquette. The burning rate of the palm waste briquette using the briquette stove was estimated to be approximately 3.0kg/hr. This value was found to be lower than values obtained when the same quantity of briquette was burnt in the open air. The technology is recommended for adoption by women preparing snacks (such as roasted yam. plantain and corn) in market places and along commercial roads.

Abstract: An alternative source of heat energy to firewood called, palm waste briquette, has been developed from oil palm fruit process wastes. These wastes (sludge, shell, fibre) are compounded in a volumetric ratio of 1:2:3 and moulded into briquettes. The performance evaluation of a low cost women friendly palm waste briquette moulding machine was carried out. The evaluation showed that the machine designed and fabricated using readily available low carbon steel (mild steel) and employing the vertical screw thread mechanism in its operation, produces three different sizes of briquette (industrial sizes, medium sizes and domestic sizes). It requires only two unskilled operators and has a daily throughput of about 1,300kg briquettes (i.e. 400 pieces-industrial size or 800 pieces-medium size or 1,600 pieces-domestic size) unlike a modified brick moulding machine which has a daily throughput of 120 pieces industrial size

Abstract: Fuzzy-based Solid Waste Management involves the application of fuzzy set theory to formulate a solid waste management algorithm by taking into account a large criterion set and an extensive number of alternatives for various levels of uncertainty in Solid Waste Management. Fuzzy method of solid waste management allows consideration of multicriteria to better manage the inherent uncertainties. The fuzzy-based approach involve determination of solid waste management alternatives, selection of basic criteria, assignment of linguistic variables, construction of membership functions, assignment of membership degree values to each criterion, determination of the best criteria combination for alternatives and the choice of the best alternative. The result shows that alternative 2 has highest degree of membership function to the decision function and therefore is the chosen option.