Mechanical Engineering

Refrigeration is the applied science which deals with reducing the temperature of a confined space and its content to a predetermined level that is below the ambient temperature. The design of a cooling table is presented. The cooling table is an innovative application in refrigeration system design. The table is a multipurpose table for maintaining a low product temperature whilst still being able to carry out other activities on the table like a conventional table. The design covers thecompressor, condenser, evaporator, table frame, table top, cabinet volume and the covers. The prototype design requires a 70W compressor for three participants.

A simple Okra threshing machine was designed, fabricated and tested to alleviate the problems associated with Okra processing in Nigeria. It is consists mainly of five units namely, the feeding assembly, the threshing unit, separation unit, power transmission unit. The overall mean threshing and cleaning efficiencies obtained were 93.95 and 99.56% respectively. Drum speed 500rpm combine with 55mm concave clearance gave the highest Threshing efficiency of 99.99%. All speeds, concave clearance combinations gave clearing efficiency above 98%. The machine threshing and cleaning efficiencies increased with increase in drum speed and decrease with increase in concave clearance. The machine is simple to operate and maintain without formal training.

This research deals with Low Cycle Fatigue (LCF) tests for three types of polymers, polyvinylchloride (PVC), polyoxymethy (POM), and polyamide (PA). The tensile test results showed that advantage cannot be taken from u y ratio and strain hardening coefficient (n) to estimate polymers behaviour under LCF test. There was a similarity in polymers behaviour with metals in the aspect of total strain, elastic strain and plastic strain curves with total cyclic number (2N). Fatigue strength exponent (b) and fatigue ductility exponent (c) for the polymers recorded values within metals limits. POM polymer showed less softening and greater transition life (NT). PA polymer exhibits sensitivity to external stress concentration in terms of reduction of transition life (NT). Softening behaviour of PA polymer increases with lower value of the notch radius.

Surface texturing by fabricating micro dimple on a surface have been proven to be very effective to improve tribological performances of sliding surfaces. Studies and research shown that micro-dimple reduced friction coefficient significantly and increase the service life of artificial hip replacement. This study aim to investigate and to compare the wear factor between four different micro-dimpled dimensions which comprise diameter, depth and pitch. The main objectives are firstly to determine parameter to fabricate micro-dimple surface, secondly to optimise surface micro-dimple pattern and finally to determine surface characterisation. Four samples have been chosen with different dimple parameter. In this experiment, pin-on-plate wear test machine was used. The result shown that wear factor at the pin for pattern 1 (1.53905 x 10-6 mm3/Nm), pattern 2 (1.50764 x 10-6 mm3/Nm) and pattern 3 (1.61234 x 10-6 mm3/Nm) were compatible with result done at the same test rig at Newcastle University, where else result for pattern 4 (3.66440 x 10-6 mm3/Nm) slightly off for varies reasons. On the other hand, there are no significant mass loss at the plates although the surface roughness of the plates have record changes. Conclusion from the experiment is wear factor from less dense micro-dimple is lower than wear factor in denser micro-dimple.

Field experiment conducted to measured Slippage, Effective field capacity, Field Efficiency, Soil Volume Disturbed and Specific Productivity Tillage in silt clay loam soil with depth 18 cm in Baghdad- Iraq. Split – split plot design under randomized complete block design with three replications using Least Significant Design 5 % was used. Three factor used in this experiment included Two types of plows included Chisel and Disk plows which represented main plot , Three Tires Inflation Pressure was second factor included 1.1 ,1.8 and 2.7 Bar, and Three forward speeds of the tillage was third factor included 2.35 , 4.25 and 6.50 km/hr. Result show chisel plow recorded best parameters performance.

Electric discharge machine (EDM) is a modern machining process with various advantages, as a result of which, its use is becoming more and more widespread.Thispaperconcernswith the influence of EDM input parameters (type of electrodes, peak current, pulse-on time and powder mixing concentration) on the induced surface residual stresses. The silicon carbide powder is mixed with the kerosene dielectric in powder mixing EDM (PMEDM) process. The experimental work was designed by using the response surface methodology (RSM). The analysis of variance (ANOVA) was used and regression models were built to predict the surface residual stresses as a response of the process for AISI D2 die steel.Empirical equationswereobtained for predicting the performance of the process.Two type of electrodes were used, the copper and graphite electrodes.The results showed that the minimum tensile surface residual stresses obtained when using the copper electrodeswith pulse current (22 A) and pulse on duration (120 µs). It is concluded that the use of graphite electrodes and kerosene dielectric alone induced minimum residual stresses with pulse current (22 A) and pulse on duration (40 µs) and with(120 µs) when using the kerosene dielectric with SiC powder mixing. The copper electrodes with kerosene dielectric alone induced residual stresses about (5%) lower than when using kerosene dielectric with 5g/l SiC powder and about (14%) lower than with graphite electrodes and (8%) when using the kerosene dielectric alone and with SiC powder, respectively.

The present paper addresses the concept of CSF in the development of new products. More specifically, the aim of this research is to study how performance is perceived and measured within the companies, and how this can be improved. The target respondents are Indian SMEs. 18 critical factors are identified and with the help of semi structured questionnaire the data is collected. The collected data is being analyzed in SPSS software. The results show that the identified factors are related to success of new product in the Indian SMEs.

This review describes the concept of Sustainable Development with emphasis on company’s approaches towards improving environmental performance and the effect of environmental legislation on the company’s performance. A proactive approach towards improving environmental performance often leads to improvement in company’s performance because resources are optimally utilised, and there is diversification in business activities through the creation of vital products from waste. Other benefits include excellent public image, reduction in the cost of landfill or landfill tax, avoidance of environmental fines, and availability of sufficient time to plan for the possible changes in the future. Environmental Management Systems and Life Cycle Analysis/Assessment of products are some of the fundamental measures required to take a proactive approach towards improving environmental performance and company’s performance. With various evidence obtained from some multinational corporations, this review confirms that the benefits of a proactive approach towards improving environmental performance of any organisation outweighs its cost.

The use of non edible oils blend in direct injection diesel engine shows its potential to reduce or control the NOx emissions. Combustion analysis of non edible and non edible blends revealed that the blends had a shorter ignition delay than diesel alone, at both full and light load, and a lower premixed burn fraction at full load. However, the diffusion burn rates were similar. The shorter ignition delay due to high cetane number of non edible oil blends has been suggested as being one of the causes of NOx increase the peak pressure and temperature increase in flame temperature in either pre mixed or diffusion burn has been followed by subsequent increase in NOx emission. This was due to reduction of carbonaceous soot concentration. The performance characteristics of an engine such as brake thermal efficiency, brake specific fuel consumption, brake power and engine torque were not much affected, up to a blend of 20% with neat diesel. The Co and particulate emissions were found to be decreasing with the % increase in blend with a subsequent increase of NOx. Thus the blending of fuel is being limited to 20% in majority of cases to obtain optimum performance and emission characteristics. This paper suggests about by using various types of non edible oils as fuel and blends directly in diesel engines by modifying properties by injecting or Trans-esterification.

The use of nanofluids as the operating fluid in the TPCT (two phase closed thermosyphon) significantly improves the heat transfer. In the present study, the performance enhancement of 6063 AA TPCT container material with cerium IV oxide nanofluid is investigated by RSM using Box-Behnken Design (BBD). According to BBD design, the process parameters are heat input (A), inclination angle of TPCT (B), and the flow rate of pure water in the condenser section (C). This work resulted in identifying the optimized set of input parameters and output response of the 6063 AA TPCT.