LINEAR PROGRAMMING APPROACH TO MODELING FOUNDRY CUPOLA FURNACE CHARGE

In order to control the specifications of the cast iron produced by the cupola furnace, it is necessary to estimate the proportions of the contents of the furnace charge. Traditionally, knowing the percentage of elements present in each constituent of charge and the loss or gain of each element, the final analysis of cast iron can be estimated by trial and error approach - a common approach in most Nigerian foundry workshops. This study presents a programming model technique used to obtain the optimum cupola furnace charge. The objective function was to minimize total cost of raw material and processing costs. The model was developed and implemented using the hypothetical process data of a Foundry workshop. The model was analysed using MATLAB Software Version 7.0. The results obtained using the model is significantly superior to the conventional trial and error approach. It is faster and brings about satisfying a lot of requests at the most minimal expense.&nbsp

Road transport accidents in Nigeria and the role of automotive active safety system

Analysis of road traffi c accidents revealed that most accidents are as a result of drivers’ errors. Over the years, active safety systems (ASS) were devised in vehicle to reduce the high level of road accidents, caused by human errors, leading to death and injuries.This study however evaluated the impacts of ASS inclusions into vehicles in Nigeria road transportation network. The objectives was to measure how ASS contributed to making driving safer and enhanced transport safety. Road accident data were collected, for a period of eleven years, from Lagos State Ministry of Economic Planning and Budget, Central Offi ce of Statistics. Quantitative analysis of the retrospective accident was conducted by computing the proportion of yearly number of vehicles involved in road accident to the total number of vehicles for each year. Results of the analysis showed that the proportion of vehicles involved in road accidents decreased from 16 in 1996 to 0.89 in 2006, the injured persons reduced from 15.58 in 1998 to 0.3 in 2006 and the death rate diminished from 4.45 in 1998 to 0.1 in 2006. These represented 94.4 %, 95 % and 95 % improvement respectively on road traffi c safety. It can therefore be concluded that the inclusions of ASS into design of modern vehicles had improved road safety in Nigeria automotive industry

Tricycles for Nigerian public transport unit: assessment of ergonomics design considerations

Tricycles are becoming more popular commercial means of transport across all Nigerian cities. This study evaluated ergonomics status of this development. Measurement of seven variables comprising, seats’ height, width and cushion inclination as well as space available for legs, back rest inclination, access/exit doors and circulation corridors, were carried out on the sampled Tricycle. The measured variables were compared with both the standard recommended for urban transport unit and the corresponding anthropometric data of users from Southwest and Eastern parts of Nigeria (SW/EN). Data were collected from 175 passengers through questionnaire to measure the degree of comfort/discomfort derived using the transit unit. Microsoft Office Excel 2007 was used for statistical analysis. About 59% of the total passengers reported discomfort using Tricycle. Among these, 26.6% complained of strains at hips/upper legs, 22.9% neck pains and 21.0% knees/lower legs. More than 23% of the affected attributed this to lack of space for legs’ adjustment. All seats’ dimensions deviated from the required standard. The z-test result also showed significant differences for 87.5% of the total measured in-element parameters when compared with corresponding 95th anthropometric data of users from SW/EN. The study showed that passengers using Tricycles are susceptible to injuries connected with awkward postures, vibrations and external contact stress. Improving design with the recommended standards for urban transport, as suggested by the finding, may help in overtaking these challenges

Enhanced proactive planning approach: a crucial to an improved workers’ safety in Western Nigeria small scale industry

This study evaluated managements’ proactive planning approach (PPA) to enhance safety among workers in South-western Nigeria small scale industry (SSI). The main objective was to rate the managements’ efforts at eliminating risk among their employees. By worker participatory and psychological survey approach, three tools were used; workplace observation (visual), management safety culture (questionnaire) and managers interviews (oral). The survey included 200 workers, 120 supervisors and 80 managers, in 82 SSI. Four steps to a safety proactive action plans (PAP), (looking for clues, prioritization of identified potential hazard, making improvements to eliminate the risk and follow up), were rated by employees on a scale from 0 to 5. Paired t-test was used to appraise the significant difference between the managers’ mean scores rated by the supervisors and other workers. 77.1% of workers and 64.2% supervisors rated their managers as either “not done at all” or “poorly done”. Workers’ scores for managers PPA had statistically significantly lower ratings (mean = 1.09, SEM = 0.22) compared to that of the supervisors rating (mean = 1.55, SEM = 0.32), with t (14) = −1.185, p = 0.784. There is a closed poor performance perception gaps, of managers’ PPA, of the two groups of employees. It can be concluded that safety is not emphasized, by managers of SSI, as overriding priority and this may have contributed to high reported injuries among their workforce. Courses to enhance managements’ understanding for inclusion of safety among the leading priorities becomes necessary. This will reduce work-related risks and promotes occupational safety and health among the group of workers

A Shoveling-related Pain Intensity Prediction Expert System for Workers’ Manual Movement of Material

In this study, a fuzzy-based expert system called the Pain Intensity Prediction Expert System (PIPES) was developed to predict pain severity risk (PSR) in shoveling-related tasks. The primary objective was to develop a non-changing rating risk assessment ergonomics tool that both efficient and comparable with those obtained from human ergonomics experts in the field of application. PIPES used fuzzy set theory (FST) to make decisions about the level of pain associated with a selected worker base on the measured task variables, namely scooping rate, scooping time, shovel load, and throw distance as input and PSR as the result. Values obtained from variable measurements from a sand shoveling task were run with PIPES, and the results were compared with the workers’ self-reported pain (WSRP) intensity using a numeric rating scale (NRS) tool. The result of validation showed that there was a strong positive relationship between WSRP NRS and PIPES NRS, with a correlation coefficient of 0.70. The independent sample t-test for mean difference showed that WSRP had a statistically significantly lower level of NRS (4.35 ± 2.1) compared to PIPES (4.75 ± 2.2), t (38) = - 0.591, p = 0.558. With a significance level of 0.001 at 95% confidence, the groups’ means were not significantly different. The study developed an expert system, PIPES, which can be used as a computerized representation of ergonomics experts, who are scarce. PIPES can be applied to construction industries, sand mine locations, and any workplace where materials are manually moved using a shovel

Review of Method Study Approach to Productivity Gain: A Multi-case Study of Portable Water Producing Factory

This study evaluated level of work-study approach (wsa) to productivity advancement in Southwest-Nigeria Portable Water Producing Factories (PWPF). Objectives were to, measure productivity trend (PT) and, evaluate managers’ recognition and contribution(s) of wsa to productivity growth. PT was measured from 4 years records provided by 50 employers in 50 PWPF. Questionnaires were used on the employers and 120 employees to measure adopted wsa and impacts with responses reported on the scale of 1 to 5. Data was analyzed using t-test statistical analysis. The best performed PWPF was rated 43.75%. Disloyalty, low remuneration, lack of trainings and unsafe workplace were the major factors reported to have influenced the PT. Machinery Utilization (MeU) maximization was the commonly adopted approach. The employers’ ratings of MeU statistically significantly lower (mean=3.6364, SEM= 0.06913) to that of employees (mean=3.7333 SEM=0.6645) t(169) =0.641, p=0.522. Human resources management (p=0.235) and workers’ performance evaluation (p=0.906) were also significant and rated above average. However, work-method, safe work-practices and work-demands reviews, which were key attributes of ergonomic techniques and workers-related factors (wrf), were not significant, rated below average. The author concluded that neglects of wrf in wsa, must have greatly contributed to the weak PT of the industry and should be properly addressed to enhance productivity growth. Keywords— ergonomic, industry, productivity, water, work-stud

Evaluation of Inhibitive Performance of Acidic Extract of Eichornia Crassipeson Corrosion of Low Carbon Steel in 1M Sulphuric Acid Solution

Corrosion inhibition potential of Eichhornia crassipes extract on low carbon steel in 1 M sulphuric acid solution was investigated using gravimetric method and corrosion rate. The experiment was carried out for 3 hours at different concentration of Eichhornia crassipes extract and temperatures of 26.6°C, 40°C and 60°C. Arrhenius and improved Arrhenius equations were used to determine the thermodynamics properties of the reaction while the nature of the reaction was proposed by adsorption isotherms. The results showed that corrosion rate decreased in the presence of the extract except in 60oC. Inhibition efficiency also increased with extract concentration with the highest (82%) occurring at room temperature and 5% concentration. Inhibition efficiency decreased with increase in temperature with almost no inhibition at 60oC, this is associated with physisorption. Activation energy () and activation enthalpy () both had positive values and they increased in the presence of Eichhornia crassipes extract, those for inhibited solution were higher than those for uninhibited solution, these can also be attributed to physisorption. Inhibition  reaction obeyed Langmuir adsorption isotherm. Gibbs free energy () calculated for the reaction is -8.509 to -11.767 kJ mol-1

Inhibitive Action of Water Extract of Spondias Mombin on Corrosion of Low Carbon Steel in 0.5 M Sulphuric Acid

Corrosion inhibition of water extract of Spondias mombin on low carbon steel in 0.5 M sulphuric acid was investigated in this paper. Fresh leaves, fruits and bark of this plant, washed properly, ground separately using small amount of distilled water to extract the juice at a ratio of 500 ml (distilled water) to 1 kilogram of plant were used for this experiment. Corrosion inhibitors of 0.4 g/ml, 1 g/ml and 2 g/ml were made from the filterate. Low carbon steel coupons suspended with twine inside 250 ml container of 0.5 M sulphuric acid in the presence of different concentrations of the extracts at room temperature for 35 days. The coupons were retrieved at 7 days interval, and the initial and final weights were recorded.  Inhibition efficiency for the leaves extract increased with concentration and got to its peak on the 7th day, that of the fruits extract initially increased with concentration until 1 g/ml after which there was a decline, its highest value was also recorded on the 7th day. The best inhibition efficiencies (in the range of 76.32% to 83.21%) for Spondias mombin water extract were observed in 0.4 g/ml bark extract throughout the days of the experiment, the highest being recorded on the14th day. It can be concluded that Spondias mombin water extract is a good corrosion inhibitor of low carbon steel in 0.5 M sulphuric acid at room temperature, with the best being the bark extract which inhibited for up to 35 days