Smart and strategic procurement, use and maintenance partnerships in engineering equipment for sustainable development and training in Sub-Saharan Africa using a systems thinking approach

Abstract: Most engineering institutions in Sub-Saharan Africa generally suffer from the persistent shortage and lack of accessibility to modern engineering equipment for the training of engineers. The old and obsolete equipment available, invariably pose challenges on the caliber of engineers being churned out to run industries in these developing countries. Based on research carried out at four engineering institutions in Sub-Saharan Africa through data collection and analysis, a smart procurement, use and maintenance strategy in the form of strategic partnerships with industry was formulated using a systems thinking approach. This paper looks at the development of this strategy and how the proposed partnerships can help in sustainable development, capacity building and ultimately bridging the gap between industry and academia. The implementation of this novel approach at the University of Zimbabwe has brought immense benefits such as students and staff access to modern equipment and technology

Design of a 10-digit inventory codification system for a tube and pipe manufacturing company in Zimbabwe

Abstract: Lack of proper inventory control usually leads to high stock-outs resulting in ‘firefighting’. This paper looks at the engineering and technical services required to maintain smooth production with the aim of developing an inventory control system for the efficient utilization of resources. A work study was carried out at a tube and pipe manufacturing company in Zimbabwe followed by an analysis outlining the operations, limitations and process flows. An inventory audit provided some insights on the company’s inventory control status. A 10-digit inventory codification system was designed based on 7 rules for generic application and capability for ‘make or buy’ decisions on spare parts. A cost benefit analysis revealed that although the project would initially be costly, a reduction in inventory can be realized through removal of slow moving and obsolete stock, realizing some annual savings in the long run, coupled with an improvement in record keeping and accountability.Lack of proper inventory control usually leads to high stock-outs resulting in ‘firefighting’. This paper looks at the engineering and technical services required to maintain smooth production with the aim of developing an inventory control system for the efficient utilization of resources. A work study was carried out at a tube and pipe manufacturing company in Zimbabwe followed by an analysis outlining the operations, limitations and process flows. An inventory audit provided some insights on the company’s inventory control status. A 10-digit inventory codification system was designed based on 7 rules for generic application and capability for ‘make or buy’ decisions on spare parts. A cost benefit analysis revealed that although the project would initially be costly, a reduction in inventory can be realized through removal of slow moving and obsolete stock, realizing some annual savings in the long run, coupled with an improvement in record keeping and accountability

Modelling, simulation and optimization of the materials flow of a multi-product assembling plant

Abstract: Various dynamic factors impact the movement of materials within a manufacturing environment, increasingly becoming complex for multi-product assembling plants owing to the multiplicity and interconnectedness of these factors. Analyzing these factors can be equally complex, requiring modelling and simulation tools. This paper looks at the modelling and simulation of the materials flow of a multi-product furniture assembling plant to develop an efficient system that accomplishes timely product deliveries at minimal cost. Generic simulation models based on 2 products were developed and constructed using Arena® Simulation Software. Following the simulation experiments and implementation of the results, the average hourly throughput was significantly increased and additional space to store materials prior to processing at workstations was created. The generic models were compatible with the company's other products and hence useful for the company’s production planning and scheduling

Process mapping and optimization of the process flows of a furniture manufacturing company in Zimbabwe using machine distance matrices

Abstract: Appropriate arrangement of machinery in a manufacturing environment can have a positive impact on the productivity of a company. A detailed work study carried out at a furniture manufacturing company revealed that parts travelled long distances before the final product is produced owing to the positions of machinery and crisscrossing process flows. This paper looks at how the plant layout was re-organized by mapping process flows and regrouping of the machinery according to their functions and products using machine distance matrices. Challenges relating to the plant layout, process flows, materials handling and transportation as well as assembly procedures were established, coupled with grouping machines according to functions and the least distance between interacting workstations. Using the machine distance matrices, processes were mapped and equipment reorganized to allow for continuous flow of production, resulting in significant reductions in transportation distances among interacting workstations and elimination of crisscrossing process paths

Spatial Variation in Fish Density at Three Petroleum Platforms as Measured with Dual-Beam Hydroacoustics

Despite the number and ubiquitous placement of petroleum platforms in the northern Gulf of Mexico, little information exists on associated fisheries resources due to the difficulties of sampling these sites with traditional fish census methods. From 1994 to 1996 dual-beam hydroacoustics were employed on quarterly research trips to measure the density and in situ target strengths of fishes associated with petroleum platforms in 20, 60, and 219 m of water. Density varied significantly with platform, distance from the platform, depth, and platform side. Platforms on the continental shelf had a near-field area of influence of approximately 18 m, whereas the near-field are of influence for the site on the continental slope was 10 m, although the relationship was not as well defined as the other sites. Average estimated abundance over the study period was 26,347 at the 60-m site, 13,444 at the 20-m site and 11,224 at the 219-m site. Fishes were distributed throughout the water column at the sites on the continental shelf, whereas on the continental slope (water depth 219m), over 88% of the fishes were found in the upper 60 m of the site

Nonlinear finite element program for reinforced concrete structural control

Abstract: Proprietary softwares are often used for structural control in engineering. Nonlinear structural control researches often uses nonlinear finite element toolbox (NLFET) code which was specifically developed for coding and simulations of structures. This paper provides an overview of the use of NLFET including the data structures and algorithms used to develop a nonlinear finite element program for reinforced concrete structural control. In order to make use of the nonlinear routines, powerful control and NLFET toolboxes, NFLET are implemented in MATLAB. The data of the structure is stored in MATLAB structures for maximum flexibility and to improve the readability of the code. Object oriented design is used to define element types so that new elements (both linear and nonlinear) can be added easily and without necessitating changes in the core analysis code. Solidworks was the software in this paper

A Spectroscopic Survey of the Fields of 28 Strong Gravitational Lenses: The Group Catalog

With a large, unique spectroscopic survey in the fields of 28 galaxy-scale strong gravitational lenses, we identify groups of galaxies in the 26 adequately-sampled fields. Using a group finding algorithm, we find 210 groups with at least five member galaxies; the median number of members is eight. Our sample spans redshifts of 0.04 $\le z_{grp} \le$ 0.76 with a median of 0.31, including 174 groups with $0.1 < z_{grp} < 0.6$. Groups have radial velocity dispersions of 60 $\le \sigma_{grp} \le$ 1200 km s$^{-1}$ with a median of 350 km s$^{-1}$. We also discover a supergroup in field B0712+472 at $z =$ 0.29 consisting of three main groups. We recover groups similar to $\sim$ 85% of those previously reported in these fields within our redshift range of sensitivity and find 187 new groups with at least five members. The properties of our group catalog, specifically 1) the distribution of $\sigma_{grp}$, 2) the fraction of all sample galaxies that are group members, and 3) the fraction of groups with significant substructure, are consistent with those for other catalogs. The distribution of group virial masses agrees well with theoretical expectations. Of the lens galaxies, 12 of 26 (46%) (B1422+231, B1600+434, B2114+022, FBQS J0951+2635, HE0435-1223, HST J14113+5211, MG0751+2716, MGJ1654+1346, PG 1115+080, Q ER 0047-2808, RXJ1131-1231, and WFI J2033-4723) are members of groups with at least five galaxies, and one more (B0712+472) belongs to an additional, visually identified group candidate. There are groups not associated with the lens that still are likely to affect the lens model; in six of 25 (24%) fields (excluding the supergroup), there is at least one massive ($\sigma_{grp} \ge$ 500 km s$^{-1}$) group or group candidate projected within 2$^{\prime}$ of the lens.Comment: 87 pages, 8 figures, a version of this was published in Ap

Development of an electric drive train for cycles as a sustainable means of transportation for a green environment

Abstract: A reliable and sustainable means of human transportation is vital for the world’s increasing pollution emissions and congestions on the motorways. The research aimed at and focused on developing an affordable electric drive train for cycles using the principle of Continuously Variable Transmission (CVT) to provide an interminable number of speed ratios by varying the pulley diameters. The planetary gears designed and installed within the CVT chamber provided a locking mechanism for the ring gear to provide forward transmission to the rear wheel where motion was stepped up through an open differential gear to propel the cycle forward. For stability and ease of manufacture and assembly, a tricycle concept was chosen and developed as a sustainable and alternative means of transportation. The developed electric drive train provides a ‘green’ and affordable means of human transportation in a world geared towards the elimination of pollution