Feasibility study of the materials handling and development of a sustainable conveying system in plastics recycling and manufacture
- Chinguwa, Simon, Nyemba, Wilson R., Boora, Kudzai, Mbohwa, Charles
- Authors: Chinguwa, Simon , Nyemba, Wilson R. , Boora, Kudzai , Mbohwa, Charles
- Date: 2019
- Subjects: Conveyor , Materials handling , Plastic manufacturing
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/295162 , uj:32133 , Citation: Chinguwa, S. et al. 2019. Feasibility study of the materials handling and development of a sustainable conveying system in plastics recycling and manufacture.
- Description: Abstract: The appropriate handling of materials in manufacturing is essential for the realization of reductions in direct and indirect costs. This research was carried out at a plastic manufacturing company in Zimbabwe where polymer pellets are used to produce plastic packaging. An in-depth work study was carried out at the plant followed by the feasibility, review and analysis of available and affordable conveying systems. A semi-automated pneumatic conveyor system comprising of a prime mover, feeder, and mixer was designed to replace the manual handling of materials. The analysis and eventual development of the optimal conveying system assisted the company in not only freeing up space for the uninterrupted movement of materials, but also improvements in safety and reduction in transportation and operational costs for the sustainable recycling and manufacture of plastic packaging. The research also contributed to the company’s product quality and variability.
- Full Text:
- Authors: Chinguwa, Simon , Nyemba, Wilson R. , Boora, Kudzai , Mbohwa, Charles
- Date: 2019
- Subjects: Conveyor , Materials handling , Plastic manufacturing
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/295162 , uj:32133 , Citation: Chinguwa, S. et al. 2019. Feasibility study of the materials handling and development of a sustainable conveying system in plastics recycling and manufacture.
- Description: Abstract: The appropriate handling of materials in manufacturing is essential for the realization of reductions in direct and indirect costs. This research was carried out at a plastic manufacturing company in Zimbabwe where polymer pellets are used to produce plastic packaging. An in-depth work study was carried out at the plant followed by the feasibility, review and analysis of available and affordable conveying systems. A semi-automated pneumatic conveyor system comprising of a prime mover, feeder, and mixer was designed to replace the manual handling of materials. The analysis and eventual development of the optimal conveying system assisted the company in not only freeing up space for the uninterrupted movement of materials, but also improvements in safety and reduction in transportation and operational costs for the sustainable recycling and manufacture of plastic packaging. The research also contributed to the company’s product quality and variability.
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Production planning and control of a master churn mixer for the manufacture of margarine using fuzzy logic at an oil company in Zimbabwe
- Nyemba, Wilson R., Mushiri, Tawanda, Mugwindiri, Kumbi, Mushonga, Roy, Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Mushiri, Tawanda , Mugwindiri, Kumbi , Mushonga, Roy , Mbohwa, Charles
- Date: 2018
- Subjects: Fuzzy logic , Master churn mixer , Production planning and control
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/270488 , uj:28751 , Citation: Nyemba, W.R. 2018. Production planning and control of a master churn mixer for the manufacture of margarine using fuzzy logic at an oil company in Zimbabwe. 2017 ACRID European Alliance for Innovation (EAI) Conference. DOI 10.4108/eai.20-6-2017.2270631 , ISBN: 9781631901607
- Description: Abstract: Process and chemical companies have to continually monitor and control their mixing equipment to ensure that production matches requirements and meets recommended standards especially in food processing. The oil company in this research faced challenges in meeting required specifications in some of their batches, prompting the need to look at more efficient ways to control and monitor the master churn mixer. This paper looks at how intelligent fuzzy logic was used to automate the production planning and control of the master churn mixer of the margarine plant. MATLAB 7.12 was used in developing the control algorithm that enabled all the inputs to be monitored closely before they entered the master churn, while maintaining vegetable oil at 80%, water at 20% and operating temperature at 38oC. This was enabled by sensors and programmable logic controllers which monitored all parameters using fuzzy logic to produce margarine of acceptable quality and standards.
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- Authors: Nyemba, Wilson R. , Mushiri, Tawanda , Mugwindiri, Kumbi , Mushonga, Roy , Mbohwa, Charles
- Date: 2018
- Subjects: Fuzzy logic , Master churn mixer , Production planning and control
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/270488 , uj:28751 , Citation: Nyemba, W.R. 2018. Production planning and control of a master churn mixer for the manufacture of margarine using fuzzy logic at an oil company in Zimbabwe. 2017 ACRID European Alliance for Innovation (EAI) Conference. DOI 10.4108/eai.20-6-2017.2270631 , ISBN: 9781631901607
- Description: Abstract: Process and chemical companies have to continually monitor and control their mixing equipment to ensure that production matches requirements and meets recommended standards especially in food processing. The oil company in this research faced challenges in meeting required specifications in some of their batches, prompting the need to look at more efficient ways to control and monitor the master churn mixer. This paper looks at how intelligent fuzzy logic was used to automate the production planning and control of the master churn mixer of the margarine plant. MATLAB 7.12 was used in developing the control algorithm that enabled all the inputs to be monitored closely before they entered the master churn, while maintaining vegetable oil at 80%, water at 20% and operating temperature at 38oC. This was enabled by sensors and programmable logic controllers which monitored all parameters using fuzzy logic to produce margarine of acceptable quality and standards.
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Modelling, simulation and optimization of the materials flow of a multi-product assembling plant
- Nyemba, Wilson R., Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2017
- Subjects: Arena® , Materials flow , Modelling
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/225005 , uj:22715 , Citation: Nyemba, W.R. & Mbohwa, C. 2017. Modelling, simulation and optimization of the materials flow of a multi-product assembling plant. 14th Global Conference on Sustainable Manufacturing, GCSM 3-5 October 2016, Stellenbosch, South Africa. DOI: 10.1016/j.promfg.2017.02.007. , ISSN: 2351-9789
- Description: 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.
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- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2017
- Subjects: Arena® , Materials flow , Modelling
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/225005 , uj:22715 , Citation: Nyemba, W.R. & Mbohwa, C. 2017. Modelling, simulation and optimization of the materials flow of a multi-product assembling plant. 14th Global Conference on Sustainable Manufacturing, GCSM 3-5 October 2016, Stellenbosch, South Africa. DOI: 10.1016/j.promfg.2017.02.007. , ISSN: 2351-9789
- Description: 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.
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Nonlinear finite element program for reinforced concrete structural control
- Mushiri, Tawanda, Nyemba, Wilson R., Mbohwa, Charles
- Authors: Mushiri, Tawanda , Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2016
- Subjects: Nonlinear control theory , Finite element method , Reinforced concrete - Quality control
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217238 , uj:21615 , Citation: Mushiri, T., Nyemba, W.R & Mbohwa, C. 2016. Nonlinear finite element program for reinforced concrete structural control.
- Description: 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.
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- Authors: Mushiri, Tawanda , Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2016
- Subjects: Nonlinear control theory , Finite element method , Reinforced concrete - Quality control
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217238 , uj:21615 , Citation: Mushiri, T., Nyemba, W.R & Mbohwa, C. 2016. Nonlinear finite element program for reinforced concrete structural control.
- Description: 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.
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Equipment maintenance challenges and solutions for capacity building and sustainability in the training of engineers : the case for the University of Zimbabwe
- Nyemba, Wilson R., Mashamba, Able, Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Mashamba, Able , Mbohwa, Charles
- Date: 2016
- Subjects: Industrial capacity , Engineering equipment - Maintenance and repair , Engineers - Training of - Zimbabwe
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/223373 , uj:22459 , Citation: Nyemba, W.R., Mashamba, A. & Mbohwa, C. 2016. Equipment maintenance challenges and solutions for capacity building and sustainability in the training of engineers : the case for the University of Zimbabwe. International Conference on Sustainable Materials Processing and Manufacturing, SMPM 2017, 23-25 January 2017, Kruger National Park. , ISSN: 2351-9789
- Description: Abstract: Engineering equipment in some Higher Education Institutions (HEIs) in Sub-Saharan Africa is underutilized, obsolete or in poor working condition owing to lack of expertise, aging or maintenance-related challenges respectively. A research initiated by the Network of Users of Scientific Equipment in Eastern and Southern Africa (NUSESA) and funded by the Swedish International Development Cooperation Agency (Sida) was carried out by 4 faculties of engineering in Southern Africa to establish common challenges, their causes and to propose solutions. The study revealed that the faculties shared similar problems such as no proper maintenance documentation, no local suppliers for spares and inadequate expertise. The importation of spares usually leads to prolonged lead times and delays in timely repairs to malfunctioning equipment and thus obsolescence. This paper proposes smart procurement partnerships between industry and HEIs, based on the findings from the University of Zimbabwe (UZ). Following the survey and analysis of data obtained, recommendations were made and implemented and have assisted in building capacity in acquisition, maintenance and management of laboratory equipment and sustaining these in the training of engineers.
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- Authors: Nyemba, Wilson R. , Mashamba, Able , Mbohwa, Charles
- Date: 2016
- Subjects: Industrial capacity , Engineering equipment - Maintenance and repair , Engineers - Training of - Zimbabwe
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/223373 , uj:22459 , Citation: Nyemba, W.R., Mashamba, A. & Mbohwa, C. 2016. Equipment maintenance challenges and solutions for capacity building and sustainability in the training of engineers : the case for the University of Zimbabwe. International Conference on Sustainable Materials Processing and Manufacturing, SMPM 2017, 23-25 January 2017, Kruger National Park. , ISSN: 2351-9789
- Description: Abstract: Engineering equipment in some Higher Education Institutions (HEIs) in Sub-Saharan Africa is underutilized, obsolete or in poor working condition owing to lack of expertise, aging or maintenance-related challenges respectively. A research initiated by the Network of Users of Scientific Equipment in Eastern and Southern Africa (NUSESA) and funded by the Swedish International Development Cooperation Agency (Sida) was carried out by 4 faculties of engineering in Southern Africa to establish common challenges, their causes and to propose solutions. The study revealed that the faculties shared similar problems such as no proper maintenance documentation, no local suppliers for spares and inadequate expertise. The importation of spares usually leads to prolonged lead times and delays in timely repairs to malfunctioning equipment and thus obsolescence. This paper proposes smart procurement partnerships between industry and HEIs, based on the findings from the University of Zimbabwe (UZ). Following the survey and analysis of data obtained, recommendations were made and implemented and have assisted in building capacity in acquisition, maintenance and management of laboratory equipment and sustaining these in the training of engineers.
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Design of a 10-digit inventory codification system for a tube and pipe manufacturing company in Zimbabwe
- Nyemba, Wilson R., Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2017
- Subjects: Inventory control , Manufacturing , Maintenance
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/224997 , uj:22714 , Citation: Nyemba, W.R. & Mbohwa, C. 2017. Design of a 10-digit inventory codification system for a tube and pipe manufacturing company in Zimbabwe. 14th Global Conference on Sustainable Manufacturing, GCSM 3-5 October 2016, Stellenbosch, South Africa. DOI: 10.1016/j.promfg.2017.02.064. , ISSN: 2351-9789
- Description: 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.
- Full Text:
- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2017
- Subjects: Inventory control , Manufacturing , Maintenance
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/224997 , uj:22714 , Citation: Nyemba, W.R. & Mbohwa, C. 2017. Design of a 10-digit inventory codification system for a tube and pipe manufacturing company in Zimbabwe. 14th Global Conference on Sustainable Manufacturing, GCSM 3-5 October 2016, Stellenbosch, South Africa. DOI: 10.1016/j.promfg.2017.02.064. , ISSN: 2351-9789
- Description: 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.
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Conceptualization of a new product development framework for eddy current braking systems for heavy vehicles in Zimbabwe
- Nyemba, Wilson R., Pote, Chris, Chikuku, Tauyanashe, Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Pote, Chris , Chikuku, Tauyanashe , Mbohwa, Charles
- Date: 2017
- Subjects: Brakes , Conceptualization , Eddy current
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/257789 , uj:27091 , Citation: Nyemba, W.R. et al. 2017. Conceptualization of a new product development framework for eddy current braking systems for heavy vehicles in Zimbabwe. Proceedings of the 2017 International Symposium on Industrial Engineering and Operations Management (IEOM) Bristol, UK, July 24-25, 2017.
- Description: Abstract: One of the most critical requirements for safety in vehicles is the availability of reliable braking systems. Most heavy vehicles in Zimbabwe employ the conventional hydraulic braking system. However changes and improvements in technology have seen the introduction of retarders that make use of magnets and eddy currents. The new technology is friction free but still deemed expensive and thus not yet readily acceptable to vehicle manufacturers for fears of reliability and cost. Hydraulic brakes are equally expensive in the long run owing to maintenance and frequent replacement of brake pads and rotors, particularly in Zimbabwe where the road infrastructure has deteriorated significantly over the years. A case study was carried out at a Zimbabwean company which specializes in the sales, service and backup of Scania heavy vehicles, with a special focus on the braking systems. The aim of the research was to conceptualize and compare various options and concepts of the eddy current retarders. Analysis for the chosen option were made for reliability and efficiency using an industrial engineering approach, with the objective of supplementing hydraulic brakes and recommending the sustainable use of such technology to the company and thereby dispelling any fears of reliability and cost.
- Full Text:
- Authors: Nyemba, Wilson R. , Pote, Chris , Chikuku, Tauyanashe , Mbohwa, Charles
- Date: 2017
- Subjects: Brakes , Conceptualization , Eddy current
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/257789 , uj:27091 , Citation: Nyemba, W.R. et al. 2017. Conceptualization of a new product development framework for eddy current braking systems for heavy vehicles in Zimbabwe. Proceedings of the 2017 International Symposium on Industrial Engineering and Operations Management (IEOM) Bristol, UK, July 24-25, 2017.
- Description: Abstract: One of the most critical requirements for safety in vehicles is the availability of reliable braking systems. Most heavy vehicles in Zimbabwe employ the conventional hydraulic braking system. However changes and improvements in technology have seen the introduction of retarders that make use of magnets and eddy currents. The new technology is friction free but still deemed expensive and thus not yet readily acceptable to vehicle manufacturers for fears of reliability and cost. Hydraulic brakes are equally expensive in the long run owing to maintenance and frequent replacement of brake pads and rotors, particularly in Zimbabwe where the road infrastructure has deteriorated significantly over the years. A case study was carried out at a Zimbabwean company which specializes in the sales, service and backup of Scania heavy vehicles, with a special focus on the braking systems. The aim of the research was to conceptualize and compare various options and concepts of the eddy current retarders. Analysis for the chosen option were made for reliability and efficiency using an industrial engineering approach, with the objective of supplementing hydraulic brakes and recommending the sustainable use of such technology to the company and thereby dispelling any fears of reliability and cost.
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A new product development framework for a timber processing company
- Nyemba, Wilson R., Mushiri, Tawanda, Mbohwa, Charles, Shoniwa, Kuda J.
- Authors: Nyemba, Wilson R. , Mushiri, Tawanda , Mbohwa, Charles , Shoniwa, Kuda J.
- Date: 2016
- Subjects: New product development , Quality function deployment , Stage-Gate modelling.
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/91902 , uj:20160 , Citation: Nyemba, W.R. et al. 2016. A new product development framework for a timber processing company.
- Description: Abstract: Customer perceptions of products continuously change over time. Marketing specialists are generally tasked with the responsibility of rebranding and product changes. However this is normally technology driven, with inputs from engineering designers and manufacturers providing the designs and feasibilities for either modifying existing designs or developing new ones. An opportunity arose at a timber processing company where a variety of products such as domestic and commercial furniture are manufactured. This paper reports on the development of a framework for formulating new products using the wide array of hard and soft wood that the company processes. A work study was conducted, focusing on the company’s production capacity, sales history of their twenty-three products, market trends and interviews with current customers. The research set out to develop innovative and new product platforms (product families) that are unique and represent the company while satisfying customer needs and requirements. A stage-gate model of the New Product Development (NPD) framework was formulated. Coupled with Quality Function Deployment (QFD) and weighted objectives, the use of the stage-gate model was demonstrated in the development of a four wheeler coffee table into a prototype. Implementation of the stage-gate model and further research into the four-wheeler coffee table were recommended as well as other areas related to NPD.
- Full Text:
- Authors: Nyemba, Wilson R. , Mushiri, Tawanda , Mbohwa, Charles , Shoniwa, Kuda J.
- Date: 2016
- Subjects: New product development , Quality function deployment , Stage-Gate modelling.
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/91902 , uj:20160 , Citation: Nyemba, W.R. et al. 2016. A new product development framework for a timber processing company.
- Description: Abstract: Customer perceptions of products continuously change over time. Marketing specialists are generally tasked with the responsibility of rebranding and product changes. However this is normally technology driven, with inputs from engineering designers and manufacturers providing the designs and feasibilities for either modifying existing designs or developing new ones. An opportunity arose at a timber processing company where a variety of products such as domestic and commercial furniture are manufactured. This paper reports on the development of a framework for formulating new products using the wide array of hard and soft wood that the company processes. A work study was conducted, focusing on the company’s production capacity, sales history of their twenty-three products, market trends and interviews with current customers. The research set out to develop innovative and new product platforms (product families) that are unique and represent the company while satisfying customer needs and requirements. A stage-gate model of the New Product Development (NPD) framework was formulated. Coupled with Quality Function Deployment (QFD) and weighted objectives, the use of the stage-gate model was demonstrated in the development of a four wheeler coffee table into a prototype. Implementation of the stage-gate model and further research into the four-wheeler coffee table were recommended as well as other areas related to NPD.
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Unlocking the economic value and potential of design for manufacture and assembly in a developing country for sustainability
- Nyemba, Wilson R., Muzoroza, R. K., Chikuku, T., Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Muzoroza, R. K. , Chikuku, T. , Mbohwa, Charles
- Date: 2017
- Subjects: DFMA , Economic analysis , Product development
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/258923 , uj:27232 , Citation: Nyemba, W.R. 2017. Unlocking the economic value and potential of design for manufacture and assembly in a developing country for sustainability.
- Description: Abstract: Design for Manufacture and Assembly (DFMA) principles are aimed at ‘doing it right the first time’ in the minimum possible time with the least or optimal number of parts. However, this depends on the operating environment and thus differs from place to place. This normally presents challenges to engineers tasked with product development, compounded by poor macro-economic conditions. Research carried out at a boilermaking company in Zimbabwe at a time when the country was facing an economic crisis revealed that due to inadequate infrastructure, the company would have lost the potential to supply ethanol storage tanks. The research was aimed at exploring the potential and maximizing the economic value of DFMA by modifying them to suit the environment and in so doing, helped the company to secure the business opportunity for the sustainable production and supply of storage tanks.
- Full Text:
- Authors: Nyemba, Wilson R. , Muzoroza, R. K. , Chikuku, T. , Mbohwa, Charles
- Date: 2017
- Subjects: DFMA , Economic analysis , Product development
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/258923 , uj:27232 , Citation: Nyemba, W.R. 2017. Unlocking the economic value and potential of design for manufacture and assembly in a developing country for sustainability.
- Description: Abstract: Design for Manufacture and Assembly (DFMA) principles are aimed at ‘doing it right the first time’ in the minimum possible time with the least or optimal number of parts. However, this depends on the operating environment and thus differs from place to place. This normally presents challenges to engineers tasked with product development, compounded by poor macro-economic conditions. Research carried out at a boilermaking company in Zimbabwe at a time when the country was facing an economic crisis revealed that due to inadequate infrastructure, the company would have lost the potential to supply ethanol storage tanks. The research was aimed at exploring the potential and maximizing the economic value of DFMA by modifying them to suit the environment and in so doing, helped the company to secure the business opportunity for the sustainable production and supply of storage tanks.
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Customization of the CAD software in a typical drawing office for a power and electricity distribution company in Zimbabwe
- Nyemba, Wilson R., Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2016
- Subjects: Computer-aided design , AutoCAD , Electric power distribution - Zimbabwe - Computer-aided design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217213 , uj:21612 , Citation: Nyemba, W.R. & Mbohwa, C. 2016. Customization of the CAD software in a typical drawing office for a power and electricity distribution company in Zimbabwe.
- Description: Abstract: Computer Aided Design (CAD) packages are normally bought off-the-shelf for a wide range of engineering disciplines. However, a single system cannot possibly meet requirements of different users as these packages are normally provided with basic primitives but no blocks for quick generations. A case study carried out at a power enterprise in Zimbabwe revealed delays in attending to faults and installations at their substations partly because of delays in the provision of working drawings. Although the company migrated from manual to CAD drawings, the techniques they employed resulted in duplications and delays. An in-house software development strategy was employed in this research to customize their AutoCAD software through an industrial engineering approach aimed at lowering man-hours by generating and storing symbols of their equipment for retrieval and use in future drawings, resulting in lead time reductions and integration with their maintenance management system to avoid duplication of tasks and information.
- Full Text:
- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2016
- Subjects: Computer-aided design , AutoCAD , Electric power distribution - Zimbabwe - Computer-aided design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217213 , uj:21612 , Citation: Nyemba, W.R. & Mbohwa, C. 2016. Customization of the CAD software in a typical drawing office for a power and electricity distribution company in Zimbabwe.
- Description: Abstract: Computer Aided Design (CAD) packages are normally bought off-the-shelf for a wide range of engineering disciplines. However, a single system cannot possibly meet requirements of different users as these packages are normally provided with basic primitives but no blocks for quick generations. A case study carried out at a power enterprise in Zimbabwe revealed delays in attending to faults and installations at their substations partly because of delays in the provision of working drawings. Although the company migrated from manual to CAD drawings, the techniques they employed resulted in duplications and delays. An in-house software development strategy was employed in this research to customize their AutoCAD software through an industrial engineering approach aimed at lowering man-hours by generating and storing symbols of their equipment for retrieval and use in future drawings, resulting in lead time reductions and integration with their maintenance management system to avoid duplication of tasks and information.
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Process mapping and optimization of the process flows of a furniture manufacturing company in Zimbabwe using machine distance matrices
- Nyemba, Wilson R., Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2017
- Subjects: Machine distance matrix , Optimisation , Plant layout
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/225013 , uj:22716 , Citation: Nyemba, W.R. & Mbohwa, C. 2017. Process mapping and optimization of the process flows of a furniture manufacturing company in Zimbabwe using machine distance matrices. 14th Global Conference on Sustainable Manufacturing, GCSM 3-5 October 2016, Stellenbosch, South Africa. DOI: 10.1016/j.promfg.2017.02.057. , Citation: 2351-9789
- Description: 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.
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- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2017
- Subjects: Machine distance matrix , Optimisation , Plant layout
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/225013 , uj:22716 , Citation: Nyemba, W.R. & Mbohwa, C. 2017. Process mapping and optimization of the process flows of a furniture manufacturing company in Zimbabwe using machine distance matrices. 14th Global Conference on Sustainable Manufacturing, GCSM 3-5 October 2016, Stellenbosch, South Africa. DOI: 10.1016/j.promfg.2017.02.057. , Citation: 2351-9789
- Description: 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.
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Process mapping, modelling and optimization of plant layouts and materials handling in manufacturing
- Nyemba, Wilson R., Mbohwa, Charles, Nyemba, L. E. N.
- Authors: Nyemba, Wilson R. , Mbohwa, Charles , Nyemba, L. E. N.
- Date: 2018
- Subjects: Manufacturing , Materials handling , Modelling
- Language: English
- Type: Book chapter
- Identifier: http://hdl.handle.net/10210/270495 , uj:28752 , Citation: Nyemba, W.R., Mbohwa, C. & Nyemba, L.E.N. 2018. Process mapping, modelling and optimization of plant layouts and materials handling in manufacturing. In Book: Transactions on Engineering Sciences.
- Description: Abstract: Documenting process flows in a manufacturing environment provides a guide to understanding how processes are interconnected and how materials are handled, thus forming the basis for modelling and optimization in order to simplify the otherwise complex systems particularly in multi-product manufacturing. Research was carried out at a furniture manufacturing company specializing in the production of a wide range of furniture from hardwood. Owing to the multiplicity of processes and the movement of materials in manufacturing environments, the factors affecting such setups increasingly become complex, equally requiring complex techniques to analyze and optimize them. A work study carried out at the company established inherent problems that affected production and were used as the basis for modelling and optimizing the processes, focusing on grouping of workstations depending on functions, predicting performance using simulation and machine distance matrices for a reorganized plant layout. Results obtained after modelling and optimizing the plant layout were useful for production planning and control as well as enhancing the company’s productivity and efficiency.
- Full Text:
Process mapping, modelling and optimization of plant layouts and materials handling in manufacturing
- Authors: Nyemba, Wilson R. , Mbohwa, Charles , Nyemba, L. E. N.
- Date: 2018
- Subjects: Manufacturing , Materials handling , Modelling
- Language: English
- Type: Book chapter
- Identifier: http://hdl.handle.net/10210/270495 , uj:28752 , Citation: Nyemba, W.R., Mbohwa, C. & Nyemba, L.E.N. 2018. Process mapping, modelling and optimization of plant layouts and materials handling in manufacturing. In Book: Transactions on Engineering Sciences.
- Description: Abstract: Documenting process flows in a manufacturing environment provides a guide to understanding how processes are interconnected and how materials are handled, thus forming the basis for modelling and optimization in order to simplify the otherwise complex systems particularly in multi-product manufacturing. Research was carried out at a furniture manufacturing company specializing in the production of a wide range of furniture from hardwood. Owing to the multiplicity of processes and the movement of materials in manufacturing environments, the factors affecting such setups increasingly become complex, equally requiring complex techniques to analyze and optimize them. A work study carried out at the company established inherent problems that affected production and were used as the basis for modelling and optimizing the processes, focusing on grouping of workstations depending on functions, predicting performance using simulation and machine distance matrices for a reorganized plant layout. Results obtained after modelling and optimizing the plant layout were useful for production planning and control as well as enhancing the company’s productivity and efficiency.
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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
- Nyemba, Wilson R., Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2018
- Subjects: Capacity building , Engineering equipment , Maintenance
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/270481 , uj:28750 , Citation: Nyemba, Wilson R. & Mbohwa, Charles. 2018. 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. 2017 ACRID European Alliance for Innovation (EAI) Conference. DOI 10.4108/eai.20-6-2017.2270632. , ISBN: 9781631901607
- Description: 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.
- Full Text:
- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2018
- Subjects: Capacity building , Engineering equipment , Maintenance
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/270481 , uj:28750 , Citation: Nyemba, Wilson R. & Mbohwa, Charles. 2018. 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. 2017 ACRID European Alliance for Innovation (EAI) Conference. DOI 10.4108/eai.20-6-2017.2270632. , ISBN: 9781631901607
- Description: 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.
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Development of an effective self-cleaning system to minimize fouling in heat exchangers
- Nyemba, Wilson R., Chinguwa, Simon, Zimba, Isheanesu, Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Chinguwa, Simon , Zimba, Isheanesu , Mbohwa, Charles
- Date: 2018
- Subjects: Condenser , Fouling , Foulant
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/285603 , uj:30889 , Citation: Nyemba, W.R. et al. 2018. Development of an effective self-cleaning system to minimize fouling in heat exchangers.
- Description: Abstract: Power plant steam condensers use cooling water for condensation of exhaust steam from turbines. Depending on the concentration of cations in the cooling water, changes in temperature result in the precipitation of insoluble metal salts on the tube walls hence impeding heat transfer, leading to fouling, a threat on the heat transfer efficiency of the condenser. The research was carried out at a power station in Zimbabwe where offline mechanical methods used to clean the tubes were observed to be slow and inefficient, hence increasing downtimes. The use of spherical rubber balls was proposed where they were injected into the cooling water to scrub off dirt on the tube surfaces as well as creating turbulence to prevent the dirt from settling on the tube walls. Ball sizes of diameter less than the tube sizes were preferred in order to cater for possible thermal expansion of the rubber material on exposure to elevated temperatures. A magnetic water treatment unit was added to facilitate the formation of weak precipitates of the metal salts for ease of removal on cleaning. The design and implementation of the research results had the potential of saving the company on downtimes during condenser cleaning.
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- Authors: Nyemba, Wilson R. , Chinguwa, Simon , Zimba, Isheanesu , Mbohwa, Charles
- Date: 2018
- Subjects: Condenser , Fouling , Foulant
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/285603 , uj:30889 , Citation: Nyemba, W.R. et al. 2018. Development of an effective self-cleaning system to minimize fouling in heat exchangers.
- Description: Abstract: Power plant steam condensers use cooling water for condensation of exhaust steam from turbines. Depending on the concentration of cations in the cooling water, changes in temperature result in the precipitation of insoluble metal salts on the tube walls hence impeding heat transfer, leading to fouling, a threat on the heat transfer efficiency of the condenser. The research was carried out at a power station in Zimbabwe where offline mechanical methods used to clean the tubes were observed to be slow and inefficient, hence increasing downtimes. The use of spherical rubber balls was proposed where they were injected into the cooling water to scrub off dirt on the tube surfaces as well as creating turbulence to prevent the dirt from settling on the tube walls. Ball sizes of diameter less than the tube sizes were preferred in order to cater for possible thermal expansion of the rubber material on exposure to elevated temperatures. A magnetic water treatment unit was added to facilitate the formation of weak precipitates of the metal salts for ease of removal on cleaning. The design and implementation of the research results had the potential of saving the company on downtimes during condenser cleaning.
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Software development of a catalogue of engineering symbols as an add-on facility for use in CAD
- Nyemba, Wilson R., Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2016
- Subjects: Computer-aided design , AutoCAD , Engineering drawings - Computer-aided design , Industrial engineering symbols
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217200 , uj:21611 , Citation: Nyemba, W.R. & Mbohwa, C. 2016. Software development of a catalogue of engineering symbols as an add-on facility for use in CAD.
- Description: Abstract: Production of engineering drawings have evolved from manual to Computer Aided Design (CAD), primarily for the speed and accuracy presented by CAD. Unlike modelling and simulation packages that are equipped with building blocks, CAD packages are generally supplied with no pre-drawn symbols. From best practices in industrial engineering and working for companies that make use of CAD systems, evidently a lot of time is spent in repetitive tasks in the development of engineering drawings. An industrial engineering approach was adopted in this research where programming was used as a separate process from any specific application to an organization through the creation of a catalogue of almost 500 commonly used engineering symbols and storing them in a database, coupled with an addon facility for AutoCAD for easy retrieval, aimed at avoiding these repetitive tasks, hence facilitating the rapid production of drawings to improve productivity and efficiency when using CAD systems.
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- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2016
- Subjects: Computer-aided design , AutoCAD , Engineering drawings - Computer-aided design , Industrial engineering symbols
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217200 , uj:21611 , Citation: Nyemba, W.R. & Mbohwa, C. 2016. Software development of a catalogue of engineering symbols as an add-on facility for use in CAD.
- Description: Abstract: Production of engineering drawings have evolved from manual to Computer Aided Design (CAD), primarily for the speed and accuracy presented by CAD. Unlike modelling and simulation packages that are equipped with building blocks, CAD packages are generally supplied with no pre-drawn symbols. From best practices in industrial engineering and working for companies that make use of CAD systems, evidently a lot of time is spent in repetitive tasks in the development of engineering drawings. An industrial engineering approach was adopted in this research where programming was used as a separate process from any specific application to an organization through the creation of a catalogue of almost 500 commonly used engineering symbols and storing them in a database, coupled with an addon facility for AutoCAD for easy retrieval, aimed at avoiding these repetitive tasks, hence facilitating the rapid production of drawings to improve productivity and efficiency when using CAD systems.
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Optimization of a plant layout and materials handling system for a furniture manufacturing company
- Nyemba, Wilson R., Mbohwa, Charles, Nyemba, Lloyd E.N.
- Authors: Nyemba, Wilson R. , Mbohwa, Charles , Nyemba, Lloyd E.N.
- Date: 2016
- Subjects: Materials handling , Plant layout , Process mapping
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/92044 , uj:20179 , Citation: Nyemba, W.R. Mbohwa, C. & Nyemba, L.E.N. 2016. Optimization of a plant layout and materials handling system for a furniture manufacturing company
- Description: Abstract: The proper layout and efficient utilization of resources; human, machinery and space can have a positive bearing on the productivity of manufacturing companies. A case study was carried out at a furniture manufacturing plant in Harare, Zimbabwe and this paper presents the findings and proposals for an optimized plant layout and materials handling system. Inherent problems within the manufacturing setup were identified through the use of questionnaires and the company’s available documentation. These ranged from crisscrossing process flows, undocumented production plans and inadequately planned materials processing and handling. Following a detailed work study, production planning and control techniques for materials handling, processing and assembly were introduced to improve production throughput times. Three alternative models were conceptualized and the best model was selected using the payback period method while optimization of the plant was achieved through a novel approach of process mapping of the layout, available space and materials handling machinery. Results obtained from the assessment of the selected model revealed that transportation distances can be reduced significantly while production throughput time decreases.
- Full Text:
- Authors: Nyemba, Wilson R. , Mbohwa, Charles , Nyemba, Lloyd E.N.
- Date: 2016
- Subjects: Materials handling , Plant layout , Process mapping
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/92044 , uj:20179 , Citation: Nyemba, W.R. Mbohwa, C. & Nyemba, L.E.N. 2016. Optimization of a plant layout and materials handling system for a furniture manufacturing company
- Description: Abstract: The proper layout and efficient utilization of resources; human, machinery and space can have a positive bearing on the productivity of manufacturing companies. A case study was carried out at a furniture manufacturing plant in Harare, Zimbabwe and this paper presents the findings and proposals for an optimized plant layout and materials handling system. Inherent problems within the manufacturing setup were identified through the use of questionnaires and the company’s available documentation. These ranged from crisscrossing process flows, undocumented production plans and inadequately planned materials processing and handling. Following a detailed work study, production planning and control techniques for materials handling, processing and assembly were introduced to improve production throughput times. Three alternative models were conceptualized and the best model was selected using the payback period method while optimization of the plant was achieved through a novel approach of process mapping of the layout, available space and materials handling machinery. Results obtained from the assessment of the selected model revealed that transportation distances can be reduced significantly while production throughput time decreases.
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Waste heat and energy recovery system from smelter off-gas for a platinum processing plant
- Nyemba, Wilson R., Mushanguri, Innocent, Chinguwa, Simon, Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Mushanguri, Innocent , Chinguwa, Simon , Mbohwa, Charles
- Date: 2017
- Subjects: Energy , Heat , Recovery
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/257785 , uj:27088 , Citation: Nyemba, W.R. et al. 2017. Waste heat and energy recovery system from smelter off-gas for a platinum processing plant. Proceedings of the 2017 International Symposium on Industrial Engineering and Operations Management (IEOM) Bristol, UK, July 24-25, 2017.
- Description: Abstract: Most mineral processing companies are energy intensive especially if smelting is used in extraction. After processing, the energy is correspondingly dissipated as heat and toxic gases, requiring stringent controls for sustainability and safety. In recent years, Southern Africa has grappled with power shortages resulting in the scaling down of company operations. Increases in manufacturing activities demand for more energy but this has evidently outstripped supply due to the depletion of natural resources. Mineral processing industries are probably the worst affected due to fluctuations in world metal prices. These challenges require sustainable production strategies to remain in business. This research was carried out at a platinum processing company in Zimbabwe which uses smelting in extractive metallurgy, consuming millions of dollars in energy but also dissipating this as heat and furnace exhaust gases. The focus of the research was on finding ways to turn these challenges into opportunities by recovering the heat and using it for other purposes. A waste heat and energy recovery system was designed to work in conjunction with the smelters and electrostatic precipitator. The proposed system is expected to increase furnace efficiency by 8.5% with an anticipated output of 1.033 MW and an overall plant efficiency of 22.7%.
- Full Text:
- Authors: Nyemba, Wilson R. , Mushanguri, Innocent , Chinguwa, Simon , Mbohwa, Charles
- Date: 2017
- Subjects: Energy , Heat , Recovery
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/257785 , uj:27088 , Citation: Nyemba, W.R. et al. 2017. Waste heat and energy recovery system from smelter off-gas for a platinum processing plant. Proceedings of the 2017 International Symposium on Industrial Engineering and Operations Management (IEOM) Bristol, UK, July 24-25, 2017.
- Description: Abstract: Most mineral processing companies are energy intensive especially if smelting is used in extraction. After processing, the energy is correspondingly dissipated as heat and toxic gases, requiring stringent controls for sustainability and safety. In recent years, Southern Africa has grappled with power shortages resulting in the scaling down of company operations. Increases in manufacturing activities demand for more energy but this has evidently outstripped supply due to the depletion of natural resources. Mineral processing industries are probably the worst affected due to fluctuations in world metal prices. These challenges require sustainable production strategies to remain in business. This research was carried out at a platinum processing company in Zimbabwe which uses smelting in extractive metallurgy, consuming millions of dollars in energy but also dissipating this as heat and furnace exhaust gases. The focus of the research was on finding ways to turn these challenges into opportunities by recovering the heat and using it for other purposes. A waste heat and energy recovery system was designed to work in conjunction with the smelters and electrostatic precipitator. The proposed system is expected to increase furnace efficiency by 8.5% with an anticipated output of 1.033 MW and an overall plant efficiency of 22.7%.
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A systems thinking approach to collaborations for capacity building and sustainability in engineering education
- Nyemba, Wilson R., Carter, Keith F., Mbohwa, Charles, Chinguwa, Simon
- Authors: Nyemba, Wilson R. , Carter, Keith F. , Mbohwa, Charles , Chinguwa, Simon
- Date: 2019
- Subjects: Capacity building , Industry-academia partnerships , Engineering education
- Language: English
- Type: Articles
- Identifier: http://hdl.handle.net/10210/295135 , uj:32129 , Citation: Nyemba, W.R. et al. 2019. A systems thinking approach to collaborations for capacity building and sustainability in engineering education.
- Description: Abstract: Please refer to full text to view abstract.
- Full Text:
- Authors: Nyemba, Wilson R. , Carter, Keith F. , Mbohwa, Charles , Chinguwa, Simon
- Date: 2019
- Subjects: Capacity building , Industry-academia partnerships , Engineering education
- Language: English
- Type: Articles
- Identifier: http://hdl.handle.net/10210/295135 , uj:32129 , Citation: Nyemba, W.R. et al. 2019. A systems thinking approach to collaborations for capacity building and sustainability in engineering education.
- Description: Abstract: Please refer to full text to view abstract.
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Data collection and statistical data analysis in preparation for simulation of a furniture manufacturing company
- Nyemba, Wilson R., Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2016
- Subjects: Data collection , Manufacturing , Statistical analysis
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/91956 , uj:20166 , Citation: Nyemba, W.R. & Mbohwa, C. 2016. Data collection and statistical data analysis in preparation for simulation of a furniture manufacturing company
- Description: Abstract: Systems that are simulated are generally made up of one or more elements that have some uncertainty associated with them. These systems may eventually evolve in a manner that is not completely predictable and thus become stochastic in nature. Simulation of stochastic systems requires that the variability of the elements in the system be characterized by probability distributions or concepts. An 'As- Is-Analysis' of the plant layout and product process flows was carried out at a furniture manufacturing company. Process data for four of their main products namely, pallets, baby tenders bunk beds and standard coffins was collected using a specially designed data sheet. An analysis of the product flow times was carried out by grouping the data into four time variables namely, material movement, processing and waiting (idle) times before and after processing at the active workstation. The distributions of these variables were obtained using graphical methods in which smooth distribution curves were generated. The gamma distribution with shape parameters of α= 3 and α=2 characterized the baby tenders while the product flow times for pallets were characterized by both the gamma distribution, α=3 and the exponential distribution with the mean varying between 14.95 and 271.78 seconds. All the data and analysis carried out produced useful information for input to the design of experiments for simulation.
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- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2016
- Subjects: Data collection , Manufacturing , Statistical analysis
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/91956 , uj:20166 , Citation: Nyemba, W.R. & Mbohwa, C. 2016. Data collection and statistical data analysis in preparation for simulation of a furniture manufacturing company
- Description: Abstract: Systems that are simulated are generally made up of one or more elements that have some uncertainty associated with them. These systems may eventually evolve in a manner that is not completely predictable and thus become stochastic in nature. Simulation of stochastic systems requires that the variability of the elements in the system be characterized by probability distributions or concepts. An 'As- Is-Analysis' of the plant layout and product process flows was carried out at a furniture manufacturing company. Process data for four of their main products namely, pallets, baby tenders bunk beds and standard coffins was collected using a specially designed data sheet. An analysis of the product flow times was carried out by grouping the data into four time variables namely, material movement, processing and waiting (idle) times before and after processing at the active workstation. The distributions of these variables were obtained using graphical methods in which smooth distribution curves were generated. The gamma distribution with shape parameters of α= 3 and α=2 characterized the baby tenders while the product flow times for pallets were characterized by both the gamma distribution, α=3 and the exponential distribution with the mean varying between 14.95 and 271.78 seconds. All the data and analysis carried out produced useful information for input to the design of experiments for simulation.
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Challenges and opportunities in adopting and implementing sustainability plans in engineering, mining and processing companies in Zimbabwe
- Nyemba, Wilson R., Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2018
- Subjects: Capacity utilization , Decision making , Sustainability planning
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/260422 , uj:27421 , Citation: Nyemba, W.R. & Mbohwa, C. 2018. Challenges and opportunities in adopting and implementing sustainability plans in engineering, mining and processing companies in Zimbabwe.
- Description: Abstract: Zimbabwe is endowed with a plethora of natural resources sufficient to provide raw materials and inputs to its engineering, mining and processing companies. Despite having inherited functional industries at independence, over the last 15 -20 years, the country has been grappling with recession, low capacity utilization, liquidation of companies and failure to export, let alone meeting local requirements. Although political instability has been largely attributed to this failure, ongoing research through surveys, interviews and direct observations at five companies involved in different business portfolios namely, furniture manufacturing, general engineering and foundry, assembly and manufacture of bus and truck bodies, backup and service of heavy vehicles as well as mineral processing, similarly revealed not only the lack of sustainability plans but also lack of involvement of all stakeholders in decision making in a systems thinking approach to ensure business continuity in different situations. The research also revealed that the failure to meet current needs without compromising the needs of the future could have contributed a great deal to low capacity utilization and eventual liquidations. Recommendations made to the companies were welcomed as clear opportunities to learn from the past and these are helping the companies to gradually recover and regain economic value in spite of the difficult operating environment.
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- Authors: Nyemba, Wilson R. , Mbohwa, Charles
- Date: 2018
- Subjects: Capacity utilization , Decision making , Sustainability planning
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/260422 , uj:27421 , Citation: Nyemba, W.R. & Mbohwa, C. 2018. Challenges and opportunities in adopting and implementing sustainability plans in engineering, mining and processing companies in Zimbabwe.
- Description: Abstract: Zimbabwe is endowed with a plethora of natural resources sufficient to provide raw materials and inputs to its engineering, mining and processing companies. Despite having inherited functional industries at independence, over the last 15 -20 years, the country has been grappling with recession, low capacity utilization, liquidation of companies and failure to export, let alone meeting local requirements. Although political instability has been largely attributed to this failure, ongoing research through surveys, interviews and direct observations at five companies involved in different business portfolios namely, furniture manufacturing, general engineering and foundry, assembly and manufacture of bus and truck bodies, backup and service of heavy vehicles as well as mineral processing, similarly revealed not only the lack of sustainability plans but also lack of involvement of all stakeholders in decision making in a systems thinking approach to ensure business continuity in different situations. The research also revealed that the failure to meet current needs without compromising the needs of the future could have contributed a great deal to low capacity utilization and eventual liquidations. Recommendations made to the companies were welcomed as clear opportunities to learn from the past and these are helping the companies to gradually recover and regain economic value in spite of the difficult operating environment.
- Full Text: