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.
- Full Text:
Cleaner production : theory and applications, case for Zimbabwe
- Mugwindiri, Kumbi, Mushiri, Tawanda
- Authors: Mugwindiri, Kumbi , Mushiri, Tawanda
- Date: 2016
- Subjects: Clean energy industries - Zimbabwe
- Language: English
- Type: Book
- Identifier: http://hdl.handle.net/10210/217634 , uj:21664 , Citation: Mugwindiri, K. & Mushiri, T. 2016. Cleaner production : theory and applications, case for Zimbabwe. , ISBN: 978-1-77920-114-0
- Description: Abstract: Regardless of its size or nature, industry generates waste and is responsible for implementing the practices of pollution prevention and waste management in its day-to-day operations. Whether it is dirty water or toxic wastes, industrial pollution is all the same in one way: it reduces a business’s profitability. Implementation of Cleaner Production (CP) urges environmental, health and safety department managers, industrial environmental consultants and personnel across all industries to employ a forwardthinking and tested technology of process improvements that will reduce waste generation, reduce the resources requirements to manufacture a product, and, most important to the life a business, increase revenues. Successful implementation of cleaner production improves their productivity, profitability, competitiveness, environmental compliance and working conditions of shop floor employees with minimum financial inputs. This book starts by explaining CP concepts, techniques and strategies. It further gives CP methodologies and case studies of those industries in which CP was successfully implemented. The authors also usher you through all sorts of exercises to test your understanding. I hope the book will encourage all stakeholders to think about what they can do to tackle the rising generation and inappropriate management of waste. Both producers and consumers of goods much work on the betterment of waste management. Every organization must strive to have the tools, technologies and financial resources to adopt CP. All sectors of society need to engage into an integrated life-cycle management of goods. The more efficient and less wasteful manufacturing and consumption processes will be, the less pressure there will be on essential resources and the better human health and the environmental will be protected. As a fellow veteran production engineer, I encourage you to recognise that this field is changing and improvements are being made that empower today’s business leader to minimize waste management generation. This book can be used as a guide if you wish to adopt CP technologies in your organizations.
- Full Text:
- Authors: Mugwindiri, Kumbi , Mushiri, Tawanda
- Date: 2016
- Subjects: Clean energy industries - Zimbabwe
- Language: English
- Type: Book
- Identifier: http://hdl.handle.net/10210/217634 , uj:21664 , Citation: Mugwindiri, K. & Mushiri, T. 2016. Cleaner production : theory and applications, case for Zimbabwe. , ISBN: 978-1-77920-114-0
- Description: Abstract: Regardless of its size or nature, industry generates waste and is responsible for implementing the practices of pollution prevention and waste management in its day-to-day operations. Whether it is dirty water or toxic wastes, industrial pollution is all the same in one way: it reduces a business’s profitability. Implementation of Cleaner Production (CP) urges environmental, health and safety department managers, industrial environmental consultants and personnel across all industries to employ a forwardthinking and tested technology of process improvements that will reduce waste generation, reduce the resources requirements to manufacture a product, and, most important to the life a business, increase revenues. Successful implementation of cleaner production improves their productivity, profitability, competitiveness, environmental compliance and working conditions of shop floor employees with minimum financial inputs. This book starts by explaining CP concepts, techniques and strategies. It further gives CP methodologies and case studies of those industries in which CP was successfully implemented. The authors also usher you through all sorts of exercises to test your understanding. I hope the book will encourage all stakeholders to think about what they can do to tackle the rising generation and inappropriate management of waste. Both producers and consumers of goods much work on the betterment of waste management. Every organization must strive to have the tools, technologies and financial resources to adopt CP. All sectors of society need to engage into an integrated life-cycle management of goods. The more efficient and less wasteful manufacturing and consumption processes will be, the less pressure there will be on essential resources and the better human health and the environmental will be protected. As a fellow veteran production engineer, I encourage you to recognise that this field is changing and improvements are being made that empower today’s business leader to minimize waste management generation. This book can be used as a guide if you wish to adopt CP technologies in your organizations.
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Condition based maintenance monitoring of gear box using fuzzy logic systems
- Mushiri, Tawanda, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Mbohwa, Charles
- Date: 2014
- Subjects: Fuzzy logic , Krones machinery , Condition based maintenance , Gearboxes
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/372086 , uj:4983 , http://hdl.handle.net/10210/13115
- Description: The purpose of this research was to come up with an intelligent monitoring tool to reduce the number of breakdowns of a beverage company bottle washer. The Fuzzy Logic system was derived among other artificial intelligent systems to be best appropriate to solve the breakdown challenges of the bottle washer. A gearbox is always jamming and it’s not easy to troubleshoot the breakdown cause and fuzzy logic is a tool that was used for monitoring. The researchers carried out a company audit, interviews and administered questionnaires in order to gather relevant data. The results were used in intelligent condition-based-maintenance modelling to solve the problem using fuzzy logic system and it was found that oil level should be always above 40% otherwise the gearbox will be made to stop. Torque is supposed to have a range of values accepted from 0-8 000Nm beyond that we consider the stoppage of the gearbox.
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- Authors: Mushiri, Tawanda , Mbohwa, Charles
- Date: 2014
- Subjects: Fuzzy logic , Krones machinery , Condition based maintenance , Gearboxes
- Type: Article
- Identifier: http://ujcontent.uj.ac.za8080/10210/372086 , uj:4983 , http://hdl.handle.net/10210/13115
- Description: The purpose of this research was to come up with an intelligent monitoring tool to reduce the number of breakdowns of a beverage company bottle washer. The Fuzzy Logic system was derived among other artificial intelligent systems to be best appropriate to solve the breakdown challenges of the bottle washer. A gearbox is always jamming and it’s not easy to troubleshoot the breakdown cause and fuzzy logic is a tool that was used for monitoring. The researchers carried out a company audit, interviews and administered questionnaires in order to gather relevant data. The results were used in intelligent condition-based-maintenance modelling to solve the problem using fuzzy logic system and it was found that oil level should be always above 40% otherwise the gearbox will be made to stop. Torque is supposed to have a range of values accepted from 0-8 000Nm beyond that we consider the stoppage of the gearbox.
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Design of a bench saw cutting machine for wood with automatic braking system
- Mushiri, Tawanda, Masarakufa, Fortune, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Masarakufa, Fortune , Mbohwa, Charles
- Date: 2016
- Subjects: Circular saws - Design and construction , Brake mechanisms - Design and construction , Circular saws - Safety measures
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217224 , uj:21614 , Citation: Mushiri, T., Masarakufa, F. & Mbohwa, C. 2016. Design of a bench saw cutting machine for wood with automatic braking system. Proceedings of the 2016 International Conference on Industrial Engineering and Operations Management, Detroit, Michigan, USA, September 23-25, 2016
- Description: Abstract: This research paper explores the design of an automatic safety brake mechanism on a manual circular table saw machine which stops the blade from rotating when human flesh is detected in the blade proximity. Fatal injuries are occurring, human thumbs and entire hand cutting during operation when operator accidentally touches the spinning blade. It has become a matter of concern to develop the safety mechanism which can be retrofitted on old-model table saw machines used to train students at a university wood workshop. The researchers made use of capacitive proximity sensors to detect human flesh and then automatically activate the brake pawl to the rotating blade, D.C. injection brake voltage which abruptly stop the running motor. The design procedure confirmed the quick release of the safety mechanism within 0.25 seconds as revealed from the simulation of circuits in Proteus software. With this design it is possible to stop the spinning blade in 0.25 seconds, before the operator touches the spinning blade and also the mechanism is adoptable to all circular saw machines (panel saw, bench saws), thus making a work-safe environment on the circular saws.
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- Authors: Mushiri, Tawanda , Masarakufa, Fortune , Mbohwa, Charles
- Date: 2016
- Subjects: Circular saws - Design and construction , Brake mechanisms - Design and construction , Circular saws - Safety measures
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217224 , uj:21614 , Citation: Mushiri, T., Masarakufa, F. & Mbohwa, C. 2016. Design of a bench saw cutting machine for wood with automatic braking system. Proceedings of the 2016 International Conference on Industrial Engineering and Operations Management, Detroit, Michigan, USA, September 23-25, 2016
- Description: Abstract: This research paper explores the design of an automatic safety brake mechanism on a manual circular table saw machine which stops the blade from rotating when human flesh is detected in the blade proximity. Fatal injuries are occurring, human thumbs and entire hand cutting during operation when operator accidentally touches the spinning blade. It has become a matter of concern to develop the safety mechanism which can be retrofitted on old-model table saw machines used to train students at a university wood workshop. The researchers made use of capacitive proximity sensors to detect human flesh and then automatically activate the brake pawl to the rotating blade, D.C. injection brake voltage which abruptly stop the running motor. The design procedure confirmed the quick release of the safety mechanism within 0.25 seconds as revealed from the simulation of circuits in Proteus software. With this design it is possible to stop the spinning blade in 0.25 seconds, before the operator touches the spinning blade and also the mechanism is adoptable to all circular saw machines (panel saw, bench saws), thus making a work-safe environment on the circular saws.
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Design of a ferrochrome – slag mechanical separator : case study
- Gudukeya, Loice Keresia, Mushiri, Tawanda, Mbohwa, Charles
- Authors: Gudukeya, Loice Keresia , Mushiri, Tawanda , Mbohwa, Charles
- Date: 2017
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/241716 , uj:24915 , Citation: Gudukeya, L.K., Mushiri, T. & Mbohwa, C. 2017. Design of a ferrochrome – slag mechanical separator : case study.
- Description: Abstract: This research focused on the design of a ferrochrome – slag mechanical separator for a company in Harare, Zimbabwe. The company’s current production is 420 tonnes of alloy per month. The aim of project is to raise the production from 420 to 500 tonnes of ferrochrome production per month by introducing a mechanical separator at metal recovery plant that produces 80 tonnes. The difference in specific gravities of ferrochrome and slag is the key principle applied in achieving separation of the two products. The densities of ferrochrome and slag are 6800 kg/ mand 2800kg/ m respectively hence gravity separation method in water medium can be done.
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- Authors: Gudukeya, Loice Keresia , Mushiri, Tawanda , Mbohwa, Charles
- Date: 2017
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/241716 , uj:24915 , Citation: Gudukeya, L.K., Mushiri, T. & Mbohwa, C. 2017. Design of a ferrochrome – slag mechanical separator : case study.
- Description: Abstract: This research focused on the design of a ferrochrome – slag mechanical separator for a company in Harare, Zimbabwe. The company’s current production is 420 tonnes of alloy per month. The aim of project is to raise the production from 420 to 500 tonnes of ferrochrome production per month by introducing a mechanical separator at metal recovery plant that produces 80 tonnes. The difference in specific gravities of ferrochrome and slag is the key principle applied in achieving separation of the two products. The densities of ferrochrome and slag are 6800 kg/ mand 2800kg/ m respectively hence gravity separation method in water medium can be done.
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Design of a fuzzy logic control system for monitoring gearbox jamming in a bottle washer machine
- Mushiri, Tawanda, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Mbohwa, Charles
- Date: 2015-03-03
- Subjects: Fuzzy logic , Gearbox jamming
- Type: Article
- Identifier: uj:5154 , http://hdl.handle.net/10210/14286
- Description: The purpose of this research was to come up with an intelligent monitoring tool to reduce the number of breakdowns of a beverage company bottle washer. The Fuzzy Logic system was derived among other artificial intelligent systems to be best appropriate to solve the breakdown challenges of the bottle washer. A gearbox is always jamming and it is not easy to troubleshoot the breakdown cause and fuzzy logic is a tool that was used for monitoring. The researchers carried out a company audit, interviews and administered questionnaires in order to gather relevant data. The results were used in intelligent condition-based-maintenance modelling to solve the problem using fuzzy logic system and it was found that oil level should be always above 40% otherwise the gearbox will be made to stop. Torque is supposed to have a range of values accepted from 0-8 000Nm beyond that we consider the stoppage of the gearbox. Very higher torques above 10000Nm damages the machinery.
- Full Text:
- Authors: Mushiri, Tawanda , Mbohwa, Charles
- Date: 2015-03-03
- Subjects: Fuzzy logic , Gearbox jamming
- Type: Article
- Identifier: uj:5154 , http://hdl.handle.net/10210/14286
- Description: The purpose of this research was to come up with an intelligent monitoring tool to reduce the number of breakdowns of a beverage company bottle washer. The Fuzzy Logic system was derived among other artificial intelligent systems to be best appropriate to solve the breakdown challenges of the bottle washer. A gearbox is always jamming and it is not easy to troubleshoot the breakdown cause and fuzzy logic is a tool that was used for monitoring. The researchers carried out a company audit, interviews and administered questionnaires in order to gather relevant data. The results were used in intelligent condition-based-maintenance modelling to solve the problem using fuzzy logic system and it was found that oil level should be always above 40% otherwise the gearbox will be made to stop. Torque is supposed to have a range of values accepted from 0-8 000Nm beyond that we consider the stoppage of the gearbox. Very higher torques above 10000Nm damages the machinery.
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Design of a mechanical cleaning device P.I.G (pipeline intervention gadget) connecting two transfer lines in Zimbabwe
- Mushiri, Tawanda, Ndlovu, Stephen, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Ndlovu, Stephen , Mbohwa, Charles
- Date: 2016
- Subjects: Pipeline intervention gadget , Pipeline , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/213988 , uj:21222 , Citation: Mushiri, T., Ndlovu, S & Mbohwa, C. 2016. Design of a mechanical cleaning device P.I.G (pipeline intervention gadget) connecting two transfer lines in Zimbabwe.
- Description: Abstract: In the Oil and Gas Industry, maintenance is done using a device or tool called a pig, chiefly to remove solids, dirt, and liquids from the pipelines. The aim of this work is to design and retrofit a pig which will clean 3 identical underground transfer pipelines linking 2 depots The movement of this tool is basically through the action of the fluid in the pipeline pushing it along as it is pumped from one point to another, hence no external power is needed in the device to help in its movement. Calculation based model analysis of the tool together with Solidworks simulations and results are included in detail, with all assumptions and limitations clearly stated and listed. The results show that the pig will move inside the pipe at a lower speed than the mean flow velocity which is good for the performance of the electronic systems installed on its body for pipeline inspection. Bypass hole is added on the central part of the pig body to control the speed as well as keep the cleaned dirt stirred and moving, being pushed by the pig as it performs its cleaning process.
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- Authors: Mushiri, Tawanda , Ndlovu, Stephen , Mbohwa, Charles
- Date: 2016
- Subjects: Pipeline intervention gadget , Pipeline , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/213988 , uj:21222 , Citation: Mushiri, T., Ndlovu, S & Mbohwa, C. 2016. Design of a mechanical cleaning device P.I.G (pipeline intervention gadget) connecting two transfer lines in Zimbabwe.
- Description: Abstract: In the Oil and Gas Industry, maintenance is done using a device or tool called a pig, chiefly to remove solids, dirt, and liquids from the pipelines. The aim of this work is to design and retrofit a pig which will clean 3 identical underground transfer pipelines linking 2 depots The movement of this tool is basically through the action of the fluid in the pipeline pushing it along as it is pumped from one point to another, hence no external power is needed in the device to help in its movement. Calculation based model analysis of the tool together with Solidworks simulations and results are included in detail, with all assumptions and limitations clearly stated and listed. The results show that the pig will move inside the pipe at a lower speed than the mean flow velocity which is good for the performance of the electronic systems installed on its body for pipeline inspection. Bypass hole is added on the central part of the pig body to control the speed as well as keep the cleaned dirt stirred and moving, being pushed by the pig as it performs its cleaning process.
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Design of a paper slitting and rewinding machine for a developing country, Zimbabwe
- Mushiri, Tawanda, Mashana, Godfrey, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Mashana, Godfrey , Mbohwa, Charles
- Date: 2016
- Subjects: Papermaking machinery - Zimbabwe - Design and construction , Paper industry - Machinery - Zimbabwe - Design and construction
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217217 , uj:21613 , Citation: Mushiri, T., Mashana, G. & Mbohwa, C. 2016. Design of a paper slitting and rewinding machine for a developing country, Zimbabwe. Proceedings of the 2016 International Conference on Industrial Engineering and Operations Management, Detroit, Michigan, USA, September 23-25, 2016
- Description: Abstract: This paper is on the design of a paper slitting and rewinding machine for a developing economy which targets small to medium enterprises (SMEs). The current problem is the high cost of such machines on the market hence most SMEs in a developing economy cannot afford them. Through careful analysis of current machines, use of alternative cheaper materials and use of more energy efficient drive mechanisms, it was possible to come up with a low cost and efficient solution. Research on the paper slitting and rewinding industry was conducted on the internet, published scholarly articles and industrial visits to local companies in the same business. The implementation of this design has major positive benefits to the development of the economy.
- Full Text:
- Authors: Mushiri, Tawanda , Mashana, Godfrey , Mbohwa, Charles
- Date: 2016
- Subjects: Papermaking machinery - Zimbabwe - Design and construction , Paper industry - Machinery - Zimbabwe - Design and construction
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217217 , uj:21613 , Citation: Mushiri, T., Mashana, G. & Mbohwa, C. 2016. Design of a paper slitting and rewinding machine for a developing country, Zimbabwe. Proceedings of the 2016 International Conference on Industrial Engineering and Operations Management, Detroit, Michigan, USA, September 23-25, 2016
- Description: Abstract: This paper is on the design of a paper slitting and rewinding machine for a developing economy which targets small to medium enterprises (SMEs). The current problem is the high cost of such machines on the market hence most SMEs in a developing economy cannot afford them. Through careful analysis of current machines, use of alternative cheaper materials and use of more energy efficient drive mechanisms, it was possible to come up with a low cost and efficient solution. Research on the paper slitting and rewinding industry was conducted on the internet, published scholarly articles and industrial visits to local companies in the same business. The implementation of this design has major positive benefits to the development of the economy.
- Full Text:
Design of a power saving industrial conveyor system
- Mushiri, Tawanda, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Mbohwa, Charles
- Date: 2016
- Subjects: Conveying machinery - Design and construction
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217269 , uj:21619 , Citation: Mushiri, T. & Mbohwa, C. 2016. Design of a power saving industrial conveyor system.
- Description: Abstract: This paper looked at the design of a power saving conveyor system which involves sizing, selection and cost benefit analysis of its installation. This paper focuses on factors that cause high belt power consumption and costs which are high starting torque and more operating hours hence there is design of drive control system consisting of soft starters and variable speed drives to reduce starting torque and load detecting switching system to reduce number of operating hours. The average power savings considering all the factors of reducing the system operating hours to the average of 12 hours a day and drive control system that reduces the starting power were calculated to be 47%. The annual costs of power consumption were reduced from $86212 to $40520 resulting in the payback period after investing to be 8 months. After doing cost benefit analysis it was ascertained that installation, operation and maintenance costs of the designed system are less than that occur on the initial system hence the design is worthy to install since it results in cost savings and increase in system life. The are some recommendations for the designed system which are clean ventilated environment to promote adequate cooling, belt protection against overload to avoid stops and also soft starters , variable speed drives and sensors protection against overvoltage and overcurrent so that the drive control system will not fail.
- Full Text:
- Authors: Mushiri, Tawanda , Mbohwa, Charles
- Date: 2016
- Subjects: Conveying machinery - Design and construction
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217269 , uj:21619 , Citation: Mushiri, T. & Mbohwa, C. 2016. Design of a power saving industrial conveyor system.
- Description: Abstract: This paper looked at the design of a power saving conveyor system which involves sizing, selection and cost benefit analysis of its installation. This paper focuses on factors that cause high belt power consumption and costs which are high starting torque and more operating hours hence there is design of drive control system consisting of soft starters and variable speed drives to reduce starting torque and load detecting switching system to reduce number of operating hours. The average power savings considering all the factors of reducing the system operating hours to the average of 12 hours a day and drive control system that reduces the starting power were calculated to be 47%. The annual costs of power consumption were reduced from $86212 to $40520 resulting in the payback period after investing to be 8 months. After doing cost benefit analysis it was ascertained that installation, operation and maintenance costs of the designed system are less than that occur on the initial system hence the design is worthy to install since it results in cost savings and increase in system life. The are some recommendations for the designed system which are clean ventilated environment to promote adequate cooling, belt protection against overload to avoid stops and also soft starters , variable speed drives and sensors protection against overvoltage and overcurrent so that the drive control system will not fail.
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Design of a rice transplanter for Zimbabwean farmers
- Mushiri, Tawanda, Gutsa, Brighton, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Gutsa, Brighton , Mbohwa, Charles
- Date: 2017
- Subjects: Rice transplanter , Musculosketal disorders , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/239109 , uj:24558 , Citation: Mushiri, T., Gutsa, B. & Mbohwa, C. 2017. Design of a rice transplanter for Zimbabwean farmers.
- Description: Abstract: Rice is a crop of growing importance in Zimbabwe but with a production of only 700 metric tonnes. This is because in wetlands it is largely grown by broadcasting of seeds and seedlings; and manual transplanting of seedlings. In practicing the said method however, farmers are exposed to musculosketal disorders as well as back problems due to the repetitive bending as well as the awkward posture needed in performing the task. Though manual transplanting gives uniform crop stand it is quite expensive and requires lot of labour besides involving lot of drudgery. Singh et al., 1985 reported that transplanting takes about 250-300 man hours/ha which is roughly 25 per cent of the total labour requirement of the crop. The rice production in Zimbabwe has also been very low because the common rice types were affected by the local climatic conditions however in 2014 businessman and farmer struck a deal with renowned Chinese agricultural scientist for National Hybrid Rice Research and Development Centre in Changsha in Hunan Province to start a pilot hybrid rice production exercise that could easily transform Zimbabwe into a major rice growing hub in the SADC region using varieties suitable to local conditions. This paper aims to design an ergonomic rice transplanter suited for the Zimbabwean climate and terrain. The mechanical transplanting of rice has been considered the most promising option, as it saves labour, ensures timely transplanting and attains optimum plant density that contributes to high productivity. Mechanization of rice sector will lead to higher productivity with releasing of work force to other sectors.
- Full Text:
- Authors: Mushiri, Tawanda , Gutsa, Brighton , Mbohwa, Charles
- Date: 2017
- Subjects: Rice transplanter , Musculosketal disorders , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/239109 , uj:24558 , Citation: Mushiri, T., Gutsa, B. & Mbohwa, C. 2017. Design of a rice transplanter for Zimbabwean farmers.
- Description: Abstract: Rice is a crop of growing importance in Zimbabwe but with a production of only 700 metric tonnes. This is because in wetlands it is largely grown by broadcasting of seeds and seedlings; and manual transplanting of seedlings. In practicing the said method however, farmers are exposed to musculosketal disorders as well as back problems due to the repetitive bending as well as the awkward posture needed in performing the task. Though manual transplanting gives uniform crop stand it is quite expensive and requires lot of labour besides involving lot of drudgery. Singh et al., 1985 reported that transplanting takes about 250-300 man hours/ha which is roughly 25 per cent of the total labour requirement of the crop. The rice production in Zimbabwe has also been very low because the common rice types were affected by the local climatic conditions however in 2014 businessman and farmer struck a deal with renowned Chinese agricultural scientist for National Hybrid Rice Research and Development Centre in Changsha in Hunan Province to start a pilot hybrid rice production exercise that could easily transform Zimbabwe into a major rice growing hub in the SADC region using varieties suitable to local conditions. This paper aims to design an ergonomic rice transplanter suited for the Zimbabwean climate and terrain. The mechanical transplanting of rice has been considered the most promising option, as it saves labour, ensures timely transplanting and attains optimum plant density that contributes to high productivity. Mechanization of rice sector will lead to higher productivity with releasing of work force to other sectors.
- Full Text:
Design of a sawdust pelleting machine
- Mushiri, Tawanda, Mugodo, Peterson, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Mugodo, Peterson , Mbohwa, Charles
- Date: 2017
- Subjects: Pelleting , Saw dust , Pelleting machine
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/239127 , uj:24559 , Citation: Mushiri, T., Mugodo, P. & Mbohwa, C. 2017. Design of a sawdust pelleting machine.
- Description: Abstract: This paper seeks to carry out the design of a pelleting machine with a capacity of 900kg per hour for the Company X. Apparently the boilers at the plant are using wood chips, a by-product from the milling operations as their source of fuel but off late the plant has been experiencing a serious fuel shortage. The fuel crisis emanated from low plant availability caused by old and dilapidated machinery. Major breakdowns that brings the plant to a halt for long hours are abrupt and rampant and during that time no wood chips are produced resulting in a fuel shortage. Following this fuel shortage the boiler operators have resorted to rationing the fuel input into the boiler as it has to run continuously regardless of whether the plant is moving or not. This rationing has resulted in poor boiler performance and low efficiency which has in turn affected the timber drying kilns. The boilers are producing poor quality steam which has had the effect of doubling the timber drying cycles. As a result of doubled timber drying cycles half of the timber produced is sold as wet off sawn at a relatively low price which is a loss to the company. The management and the engineering team in a bid to do away with this problem proposed the use of sawdust as additional boiler fuel. After a consideration of the type of boiler fire grates at the plant it was found that raw sawdust cannot be used as it has a tendency of choking the grates blowing out combustion so it has to be pelletized. With this problem at hand this project zeroed in at the design and development of a pelleting machine that will specifically meet the pellets need at the wattle company. Literature review was done on several types of pelleting machines’ operating mechanisms and from this literature three possible concepts were generated. These concepts were evaluated and the best was chosen and developed into a finished design ready for fabrication with all working drawings available for each component. The machine was designed with a constraint budget of USD $10 000 and it will provide a backup and additional boiler fuel to the already being used wood chips.
- Full Text:
- Authors: Mushiri, Tawanda , Mugodo, Peterson , Mbohwa, Charles
- Date: 2017
- Subjects: Pelleting , Saw dust , Pelleting machine
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/239127 , uj:24559 , Citation: Mushiri, T., Mugodo, P. & Mbohwa, C. 2017. Design of a sawdust pelleting machine.
- Description: Abstract: This paper seeks to carry out the design of a pelleting machine with a capacity of 900kg per hour for the Company X. Apparently the boilers at the plant are using wood chips, a by-product from the milling operations as their source of fuel but off late the plant has been experiencing a serious fuel shortage. The fuel crisis emanated from low plant availability caused by old and dilapidated machinery. Major breakdowns that brings the plant to a halt for long hours are abrupt and rampant and during that time no wood chips are produced resulting in a fuel shortage. Following this fuel shortage the boiler operators have resorted to rationing the fuel input into the boiler as it has to run continuously regardless of whether the plant is moving or not. This rationing has resulted in poor boiler performance and low efficiency which has in turn affected the timber drying kilns. The boilers are producing poor quality steam which has had the effect of doubling the timber drying cycles. As a result of doubled timber drying cycles half of the timber produced is sold as wet off sawn at a relatively low price which is a loss to the company. The management and the engineering team in a bid to do away with this problem proposed the use of sawdust as additional boiler fuel. After a consideration of the type of boiler fire grates at the plant it was found that raw sawdust cannot be used as it has a tendency of choking the grates blowing out combustion so it has to be pelletized. With this problem at hand this project zeroed in at the design and development of a pelleting machine that will specifically meet the pellets need at the wattle company. Literature review was done on several types of pelleting machines’ operating mechanisms and from this literature three possible concepts were generated. These concepts were evaluated and the best was chosen and developed into a finished design ready for fabrication with all working drawings available for each component. The machine was designed with a constraint budget of USD $10 000 and it will provide a backup and additional boiler fuel to the already being used wood chips.
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Design of an automatic tyre pressure inflation system for small vehicles
- Mushiri, Tawanda, Muzhanje, Allan T., Mbohwa, Charles
- Authors: Mushiri, Tawanda , Muzhanje, Allan T. , Mbohwa, Charles
- Date: 2016
- Subjects: Automobiles - Tyres - Inflation pressure
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217266 , uj:21620 , Citation: Mushiri, T., Muzhanje, A.T. & Mbohwa, C. 2016. Design of an automatic tyre pressure inflation system for small vehicles. Proceedings of the 2016 International Conference on Industrial Engineering and Operations Management, Detroit, Michigan, USA, September 23-25, 2016
- Description: Abstract: The advent of the tyre/automotive industry brought to a halt the savage days of long journeying by foot and suddenly introduced quick inter-city visits whilst the traveler is seated. In a bid to improve and perfect this modern way of journeying this paper focuses on the optimization of the automobile, subject matter being the effective and proper maintenance of the tyre so as to curb the disappointment of failing to travel due to underinflated tyres. The design presented in the report herein functions to restore the tyre pressure on vehicles so that they are kept at optimum pressure levels, thus extending their life time at the same time saving the owner from fuel costs and maintenance cost incurred with underinflated tyres. It constitutes of a wind driven turbine-compressor unit which uses drag wind as source of drive to a turbine and quickly converts it to rotational energy which powers a small compressor that feeds the tyre with pressurized air whenever the need arises. The system is monitored and controlled by a Java/Android program which detects low pressure and initiates compressor ON / OFF states. The system is environmentally friendly releasing zero gases and is self-sustaining using independent power source from that of the vehicle itself.
- Full Text:
- Authors: Mushiri, Tawanda , Muzhanje, Allan T. , Mbohwa, Charles
- Date: 2016
- Subjects: Automobiles - Tyres - Inflation pressure
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217266 , uj:21620 , Citation: Mushiri, T., Muzhanje, A.T. & Mbohwa, C. 2016. Design of an automatic tyre pressure inflation system for small vehicles. Proceedings of the 2016 International Conference on Industrial Engineering and Operations Management, Detroit, Michigan, USA, September 23-25, 2016
- Description: Abstract: The advent of the tyre/automotive industry brought to a halt the savage days of long journeying by foot and suddenly introduced quick inter-city visits whilst the traveler is seated. In a bid to improve and perfect this modern way of journeying this paper focuses on the optimization of the automobile, subject matter being the effective and proper maintenance of the tyre so as to curb the disappointment of failing to travel due to underinflated tyres. The design presented in the report herein functions to restore the tyre pressure on vehicles so that they are kept at optimum pressure levels, thus extending their life time at the same time saving the owner from fuel costs and maintenance cost incurred with underinflated tyres. It constitutes of a wind driven turbine-compressor unit which uses drag wind as source of drive to a turbine and quickly converts it to rotational energy which powers a small compressor that feeds the tyre with pressurized air whenever the need arises. The system is monitored and controlled by a Java/Android program which detects low pressure and initiates compressor ON / OFF states. The system is environmentally friendly releasing zero gases and is self-sustaining using independent power source from that of the vehicle itself.
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Design of an electrically powered bending machine : case of Zimbabwe
- Mushiri, Tawanda, Shumba, Definite, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Shumba, Definite , Mbohwa, Charles
- Date: 2017
- Subjects: Bending machine , Case study , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/239089 , uj:24554 , Citation: Mushiri, T., Shumba, D. & Mbohwa, C. 2017. Design of an electrically powered bending machine : case of Zimbabwe.
- Description: Abstract: This paper seeks to carry out design of a small scale electrically powered bending machine for a developing nation, case for Zimbabwe. The bending of metal is of great importance in the manufacture of products such as nut shelling machines and maize shelling machines. Currently being used at Company X engineering is a manual bending machine with a single operation hence this design will help to increase the number of metals being bent, an increase in the efficiency and production. The paper deals with manufacturing or bending of sheet metal by using power operated sheet bending machine. Especially discussion made the productivity analysis of manually or power operated sheet bending machine. Considering manual operation is replaced by power operated devices. It also gives information about limitation of manually operated sheet bending machine and power operated sheet bending machine. The existing machines are limited to a single operation. The aim of the research is to increase the number of bent parts and to place an adjustable table to suit the height of the user thereby reducing back pain internal injuries in the long run. The researchers visited the Company X to gather information concerning the problems faced by the employees. Material tests which are of great value were carried out and the use of software. A Plate Rolling Machine is a machine that will roll different kinds of metal sheet into a round or conical shape and a rod bending machine will roll or bend different kinds of metal sheet into right angles or circular shapes. The research aims at making it possible to do the operations on a single machine. We recommend the machine to be automated and the use of a servo motor to reduce human injuries at the workshop. Use of oils and maintenance is of great value to increase the life span of the machine.
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- Authors: Mushiri, Tawanda , Shumba, Definite , Mbohwa, Charles
- Date: 2017
- Subjects: Bending machine , Case study , Design
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/239089 , uj:24554 , Citation: Mushiri, T., Shumba, D. & Mbohwa, C. 2017. Design of an electrically powered bending machine : case of Zimbabwe.
- Description: Abstract: This paper seeks to carry out design of a small scale electrically powered bending machine for a developing nation, case for Zimbabwe. The bending of metal is of great importance in the manufacture of products such as nut shelling machines and maize shelling machines. Currently being used at Company X engineering is a manual bending machine with a single operation hence this design will help to increase the number of metals being bent, an increase in the efficiency and production. The paper deals with manufacturing or bending of sheet metal by using power operated sheet bending machine. Especially discussion made the productivity analysis of manually or power operated sheet bending machine. Considering manual operation is replaced by power operated devices. It also gives information about limitation of manually operated sheet bending machine and power operated sheet bending machine. The existing machines are limited to a single operation. The aim of the research is to increase the number of bent parts and to place an adjustable table to suit the height of the user thereby reducing back pain internal injuries in the long run. The researchers visited the Company X to gather information concerning the problems faced by the employees. Material tests which are of great value were carried out and the use of software. A Plate Rolling Machine is a machine that will roll different kinds of metal sheet into a round or conical shape and a rod bending machine will roll or bend different kinds of metal sheet into right angles or circular shapes. The research aims at making it possible to do the operations on a single machine. We recommend the machine to be automated and the use of a servo motor to reduce human injuries at the workshop. Use of oils and maintenance is of great value to increase the life span of the machine.
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Development of a fuzzy logic power optimization system for a refrigeration plant
- Mushiri, Tawanda, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Mbohwa, Charles
- Date: 2014
- Subjects: Compressor capacity control , Power optimization , Fuzzy controlled synchronous motors , Power factor correction , Industrial refrigeration plants
- Type: Article
- Identifier: uj:5023 , http://hdl.handle.net/10210/13166
- Description: Despite the fact that electrical power is a major overhead in industrial refrigeration plants, this resource still lacks full utilization in some plants of some organizations in developing countries. An unfortunate consequence of this predicament is that these organizations end up paying for more power than they have actually consumed or even necessarily need. This research however addresses solutions to the above concerns through the development of a power optimization system. Since power optimization is a broad subject the scope was only limited to power factor correction and compressor capacity control. The developed optimal design consisted of replacing part of the inductive load by a fuzzy controlled synchronous motor. The torque angle at the synchronous motor shaft was continuously regulated by the automatic compressor capacity control schematic. Simulations carried out using MATLAB RB2010 are also presented.
- Full Text:
- Authors: Mushiri, Tawanda , Mbohwa, Charles
- Date: 2014
- Subjects: Compressor capacity control , Power optimization , Fuzzy controlled synchronous motors , Power factor correction , Industrial refrigeration plants
- Type: Article
- Identifier: uj:5023 , http://hdl.handle.net/10210/13166
- Description: Despite the fact that electrical power is a major overhead in industrial refrigeration plants, this resource still lacks full utilization in some plants of some organizations in developing countries. An unfortunate consequence of this predicament is that these organizations end up paying for more power than they have actually consumed or even necessarily need. This research however addresses solutions to the above concerns through the development of a power optimization system. Since power optimization is a broad subject the scope was only limited to power factor correction and compressor capacity control. The developed optimal design consisted of replacing part of the inductive load by a fuzzy controlled synchronous motor. The torque angle at the synchronous motor shaft was continuously regulated by the automatic compressor capacity control schematic. Simulations carried out using MATLAB RB2010 are also presented.
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Fuzzy logic and condition-based maintenance approaches to machine failure analysis
- Authors: Mushiri, Tawanda
- Date: 2017
- Subjects: Fuzzy logic , Fuzzy systems - Industrial applications , System failures (Engineering) , Reliability (Engineering)
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/243068 , uj:25088
- Description: D.Ing. (Engineering Management) , Abstract: When the complexity of the controller plant is a non-linear system, the production process cannot be fulfilled by the control effect and it is not easy to manipulate the parameters on Proportional-Integral-Derivative Controller. The major objective under study is simulating and modelling machinery then come up with a suitable intelligent Condition Based Maintenance system (i.e to develop a suitable intelligent system using fuzzy logic and artificial intelligence). The area under study of Fuzzy Logic came as a concern of nonlinear systems which fail to give correct information since machines use conventional Proportional-Integral-Derivative and hence this is for linear systems. Considering vibrations and continuous failure of machines, this will cause incorrect data portraying. Three companies were done in this thesis and all were analysed using fuzzy logic and some finite element analysis of components to monitor the parameters. Root cause analysis was also done to determine what was failing on different equipments. Three companies in a developing country were used as case studies for testing fuzzy logic approaches and models to machinery failure analysis. The three companies are designated as follows: Beverages Production Company, Hydro Power Generating Company and Water Distributing Company. The overall effectiveness of the companies were heavily affected due to many breakdowns. The main problem was found to be resulting from failure to monitor nonlinear systems that naturally exist in such environments. On the bottle washer at Beverages Production Company, fuzzy logic with Model Reference Adaptive Control to prevent failure on the bottle washer and introduce an intelligent Condition Based Maintenance program was done, a solution to come up with a control system that monitors water in the dam as well as protecting the equipment from failure and do stability control of machinery for Water Distributing Company as well as apply the concept of Maintenance Free Operating Period reliability metric to determine maintenance intervals as opposed to Mean Time Between Failure to the Hydro-Power Generation Company and also do a Simulink control on the governor. The results of the simulation of the control strategy of Fuzzy Logic Proportional-Integral-Derivative Controller have much preferred performance as compared to the general Proportional-Integral-Derivative Controller. This was done in the Simulink/Matlab simulation environment. The innovations behind this thesis at Beverages Production Company, the pneumatic valve of the bottle washer which controls the discharge of clean bottles was occasionally sticking or failing resulting in significant loss of production in the plant since all the other processes which follow depend on the bottle washer. The main causes of failure were caused by poor control of temperature and pressure. Excessive moisture and abrasive particles also caused failures. In order to solve this problem a Model Reference Adaptive Fuzzy Controller was designed for the pneumatic valve using the Matlab software. The error resulting from the difference between the actual system output and that of the reference model was executed by the Fuzzy Logic Controller. At company Hydro-Power Generation Company, the administering system of a 150 Megawatts Francis Turbine was developed using fuzzy logic. The representative framework parameters were mirrored with the real information accessible in the power plant. At Water Distributing Company the problem of corroding gates and failure was solved using solid works, Matlab, Programmable Logic Controller and Simulink. The sluice gate valve was controlled and done stability by Matlab to avoid failure. After fuzzy logic is applied in each and every company under study, the breakdowns will be less and machinery can be diagnosed and prognosis is easy to foresee the failures. A new gate was designed by the researcher. The research has shown that fuzzy logic being intelligent, machinery can last longer and production is high. The limitations are that although it is good in monitoring but in some machinery and companies may not work well because of environment like in the water gates. It is also expensive to implement and difficult to convince management to do the research for a start.
- Full Text:
- Authors: Mushiri, Tawanda
- Date: 2017
- Subjects: Fuzzy logic , Fuzzy systems - Industrial applications , System failures (Engineering) , Reliability (Engineering)
- Language: English
- Type: Doctoral (Thesis)
- Identifier: http://hdl.handle.net/10210/243068 , uj:25088
- Description: D.Ing. (Engineering Management) , Abstract: When the complexity of the controller plant is a non-linear system, the production process cannot be fulfilled by the control effect and it is not easy to manipulate the parameters on Proportional-Integral-Derivative Controller. The major objective under study is simulating and modelling machinery then come up with a suitable intelligent Condition Based Maintenance system (i.e to develop a suitable intelligent system using fuzzy logic and artificial intelligence). The area under study of Fuzzy Logic came as a concern of nonlinear systems which fail to give correct information since machines use conventional Proportional-Integral-Derivative and hence this is for linear systems. Considering vibrations and continuous failure of machines, this will cause incorrect data portraying. Three companies were done in this thesis and all were analysed using fuzzy logic and some finite element analysis of components to monitor the parameters. Root cause analysis was also done to determine what was failing on different equipments. Three companies in a developing country were used as case studies for testing fuzzy logic approaches and models to machinery failure analysis. The three companies are designated as follows: Beverages Production Company, Hydro Power Generating Company and Water Distributing Company. The overall effectiveness of the companies were heavily affected due to many breakdowns. The main problem was found to be resulting from failure to monitor nonlinear systems that naturally exist in such environments. On the bottle washer at Beverages Production Company, fuzzy logic with Model Reference Adaptive Control to prevent failure on the bottle washer and introduce an intelligent Condition Based Maintenance program was done, a solution to come up with a control system that monitors water in the dam as well as protecting the equipment from failure and do stability control of machinery for Water Distributing Company as well as apply the concept of Maintenance Free Operating Period reliability metric to determine maintenance intervals as opposed to Mean Time Between Failure to the Hydro-Power Generation Company and also do a Simulink control on the governor. The results of the simulation of the control strategy of Fuzzy Logic Proportional-Integral-Derivative Controller have much preferred performance as compared to the general Proportional-Integral-Derivative Controller. This was done in the Simulink/Matlab simulation environment. The innovations behind this thesis at Beverages Production Company, the pneumatic valve of the bottle washer which controls the discharge of clean bottles was occasionally sticking or failing resulting in significant loss of production in the plant since all the other processes which follow depend on the bottle washer. The main causes of failure were caused by poor control of temperature and pressure. Excessive moisture and abrasive particles also caused failures. In order to solve this problem a Model Reference Adaptive Fuzzy Controller was designed for the pneumatic valve using the Matlab software. The error resulting from the difference between the actual system output and that of the reference model was executed by the Fuzzy Logic Controller. At company Hydro-Power Generation Company, the administering system of a 150 Megawatts Francis Turbine was developed using fuzzy logic. The representative framework parameters were mirrored with the real information accessible in the power plant. At Water Distributing Company the problem of corroding gates and failure was solved using solid works, Matlab, Programmable Logic Controller and Simulink. The sluice gate valve was controlled and done stability by Matlab to avoid failure. After fuzzy logic is applied in each and every company under study, the breakdowns will be less and machinery can be diagnosed and prognosis is easy to foresee the failures. A new gate was designed by the researcher. The research has shown that fuzzy logic being intelligent, machinery can last longer and production is high. The limitations are that although it is good in monitoring but in some machinery and companies may not work well because of environment like in the water gates. It is also expensive to implement and difficult to convince management to do the research for a start.
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Method of lines based on finite element technique to analyse electromagnetic problems
- Mushiri, Tawanda, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Mbohwa, Charles
- Date: 2015-03-03
- Subjects: Method of lines , Computational electromagnetics , Variational analysis , Finite element method
- Type: Article
- Identifier: uj:5159 , http://hdl.handle.net/10210/14291
- Description: A hybrid scheme called finite element method of lines is described and proposed for modelling and analysis of generalized computational electromagnetic problems with emphasis on a number of irregular waveguide. This finite element based method of lines is developed by combining finite element method and the method of lines, so that it not only has high flexibility to treat geometrically and compositionally complex problems but also maintains high accuracy of semi-analytical technique. Analytical and numerical algorithmic building blocks of this new scheme are discussed such as geometry discretization, element mapping, element trial functions, reformulation and computational issues of non-linear ordinary differential equations. The results therefore show that this new technique is able to efficiently solve complex problems as compared with the conventional method of lines. MATLAB was used to compute the solutions of various problems.
- Full Text:
- Authors: Mushiri, Tawanda , Mbohwa, Charles
- Date: 2015-03-03
- Subjects: Method of lines , Computational electromagnetics , Variational analysis , Finite element method
- Type: Article
- Identifier: uj:5159 , http://hdl.handle.net/10210/14291
- Description: A hybrid scheme called finite element method of lines is described and proposed for modelling and analysis of generalized computational electromagnetic problems with emphasis on a number of irregular waveguide. This finite element based method of lines is developed by combining finite element method and the method of lines, so that it not only has high flexibility to treat geometrically and compositionally complex problems but also maintains high accuracy of semi-analytical technique. Analytical and numerical algorithmic building blocks of this new scheme are discussed such as geometry discretization, element mapping, element trial functions, reformulation and computational issues of non-linear ordinary differential equations. The results therefore show that this new technique is able to efficiently solve complex problems as compared with the conventional method of lines. MATLAB was used to compute the solutions of various problems.
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Modelling, simulation and optimization of the comminution and flotation circuits of platinum for sustainable mineral processing
- Nyemba, Wilson R., Kapumha, Zvikomborero B., Mushiri, Tawanda, Mbohwa, Charles
- Authors: Nyemba, Wilson R. , Kapumha, Zvikomborero B. , Mushiri, Tawanda , Mbohwa, Charles
- Date: 2020
- Subjects: Comminution , Modelling , Flotation
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/438718 , uj:38142 , Citation: Nyemba, W.R. et al. 2020. Modelling, simulation and optimization of the comminution and flotation circuits of platinum for sustainable mineral processing.
- Description: Abstract: The quantum of minerals extracted from ore is critical for the success of mineral processing, hence the necessity to optimize the process flows in order to recover as much minerals as possible. The aim of this research was to identify bottlenecks and recovery-hampering factors within the comminution and flotation circuits of the concentrator plant at a platinum processing company in Zimbabwe. Modelling and simulation of the circuits were carried using Arena and Limn simulation software to optimize the process flows for improved throughput, maximum mineral recovery and enhanced efficiency and productivity. Alternative configurations of the layout of equipment were experimented on and compared with the original setup. The recommended reconfiguration of the circuits achieved increases of 2.97% in mineral recovery and 4 grams/ton in productivity resulting in a maximized output for the sustainable processing of platinum ore.
- Full Text:
- Authors: Nyemba, Wilson R. , Kapumha, Zvikomborero B. , Mushiri, Tawanda , Mbohwa, Charles
- Date: 2020
- Subjects: Comminution , Modelling , Flotation
- Language: English
- Type: Article
- Identifier: http://hdl.handle.net/10210/438718 , uj:38142 , Citation: Nyemba, W.R. et al. 2020. Modelling, simulation and optimization of the comminution and flotation circuits of platinum for sustainable mineral processing.
- Description: Abstract: The quantum of minerals extracted from ore is critical for the success of mineral processing, hence the necessity to optimize the process flows in order to recover as much minerals as possible. The aim of this research was to identify bottlenecks and recovery-hampering factors within the comminution and flotation circuits of the concentrator plant at a platinum processing company in Zimbabwe. Modelling and simulation of the circuits were carried using Arena and Limn simulation software to optimize the process flows for improved throughput, maximum mineral recovery and enhanced efficiency and productivity. Alternative configurations of the layout of equipment were experimented on and compared with the original setup. The recommended reconfiguration of the circuits achieved increases of 2.97% in mineral recovery and 4 grams/ton in productivity resulting in a maximized output for the sustainable processing of platinum ore.
- Full Text:
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.
- Full Text:
- 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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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.
- Full Text:
- 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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The use of autonomous maintenance in the fertilizer industry in Zimbabwe
- Mushiri, Tawanda, Mugwindiri, Kumbirayi, Mbohwa, Charles
- Authors: Mushiri, Tawanda , Mugwindiri, Kumbirayi , Mbohwa, Charles
- Date: 2016
- Subjects: Autonomous maintenance , Manufacturing industries - Zimbabwe - Automatic control , Fertilizer industry - Zimbabwe - Automatic control
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217249 , uj:21617 , Citation: Mushiri, T., Mugwindiri, K. & Mbohwa, C. 2016. The use of autonomous maintenance in the fertilizer industry in Zimbabwe.
- Description: Abstract: The paper seeks to give a guideline on the implementation of Autonomous Maintenance in a typical manufacturing facility. It details the chronic and perennial problems besetting typical developing countries maintenance regime scenarios. It then proffers a simple but concise paradigm shift toward the adoption and use of Autonomous Maintenance. A thorough literature exposé is articulated which it is hoped should cement the benefits of Autonomous Maintenance. Autonomous Maintenance is a dynamic, teambased methodology for involving all employees in identifying and eliminating equipment related losses such as equipment failure, lengthy set-up time, inconsistent adjustment procedures, idling and minor stoppages, reduced production yields, processing defects, etc. The importance of teams in goal attainment is highlighted and finally the paper concludes by articulating the World famous 5’s due to Nakajima and incorporates these in the implementation of Autonomous Maintenance.
- Full Text:
- Authors: Mushiri, Tawanda , Mugwindiri, Kumbirayi , Mbohwa, Charles
- Date: 2016
- Subjects: Autonomous maintenance , Manufacturing industries - Zimbabwe - Automatic control , Fertilizer industry - Zimbabwe - Automatic control
- Language: English
- Type: Conference proceedings
- Identifier: http://hdl.handle.net/10210/217249 , uj:21617 , Citation: Mushiri, T., Mugwindiri, K. & Mbohwa, C. 2016. The use of autonomous maintenance in the fertilizer industry in Zimbabwe.
- Description: Abstract: The paper seeks to give a guideline on the implementation of Autonomous Maintenance in a typical manufacturing facility. It details the chronic and perennial problems besetting typical developing countries maintenance regime scenarios. It then proffers a simple but concise paradigm shift toward the adoption and use of Autonomous Maintenance. A thorough literature exposé is articulated which it is hoped should cement the benefits of Autonomous Maintenance. Autonomous Maintenance is a dynamic, teambased methodology for involving all employees in identifying and eliminating equipment related losses such as equipment failure, lengthy set-up time, inconsistent adjustment procedures, idling and minor stoppages, reduced production yields, processing defects, etc. The importance of teams in goal attainment is highlighted and finally the paper concludes by articulating the World famous 5’s due to Nakajima and incorporates these in the implementation of Autonomous Maintenance.
- Full Text: