Showing items 1 - 20 of 1676

Causes and impact of human error in maintenance of mechanical systems

- Nkosi, Mfundo, Gupta, Kapil, Mashinini, Madindwa

  • Authors: Nkosi, Mfundo , Gupta, Kapil , Mashinini, Madindwa
  • Date: 2020
  • Subjects: Failure , Human error , Human factor
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/411127 , uj:34536 , Citation: Nkosi, M., Gupta, K. & Mashinini, M. 2020. Causes and impact of human error in maintenance of mechanical systems.
  • Description: Abstract: The concept of minimizing human error in maintenance is progressively gaining attention in various industries. The incorporation of human factors when solving engineering problems, particularly in maintenance, can no longer be ignored where high standards of performance are expected. The journey of improving maintenance performance through the reduction of human error begins with the understanding of causes and impact of human error in maintenance. This paper evaluates previous scholarly writings on human errors, to specifically establish the causes and impact of human error in maintenance. This study relies predominantly on the existing literature on human error in maintenance derived from published and unpublished research. The primary findings emerging from the research exhibit a number of key factors that cause a human error in maintenance such as poor management and supervision, organizational culture, incompetence, poorly written procedures, poor communication, time pressure, plant and environmental conditions, poor work design and many more. The literature review also revealed that human errors have a negative impact on safety, reliability, productivity and efficiency of the equipment. It was further discovered that equipment failures leading to accidents, incidents, loss of life and economic losses are the major effects of human error. Human error in mechanical systems’ maintenance is a serious problem which needs adequate attention in order to develop corrective and preventive measures. This review paper serves as a basis for maintenance practitioners and interested parties to develop corrective and preventive measures for minimizing human error in the maintenance of mechanical systems.
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Enhanced process parameters using TOPSIS method during Wire electro discharge machining of TiNiCo shape memory alloy

- Soni, Hargovind, Narendranath, S., Ramesh, M.R., Mashinini, P.M.

  • Authors: Soni, Hargovind , Narendranath, S. , Ramesh, M.R. , Mashinini, P.M.
  • Date: 2020
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/411143 , uj:34538 , Citation: Soni, H. et al. 2020. Enhanced process parameters using TOPSIS method during Wire electro discharge machining of TiNiCo shape memory alloy.
  • Description: Abstract: Shape memory alloys (SMAs) are most usable material in the field of biomedical, aerospace and robotics applications due to their unique class of properties. Super elasticity, shape memory effect and two phase transformation behaviour of these alloys make unique material. Machining of such kind of material is quite difficult through conventional machining process hence non-conventional machining of these materials is suitable. Ti50Ni40Co10 shape memory alloy was developed through Vacuum arc melting furnace for the present study. Wire electro discharge machining (A Non-conventional Machining) was used for machining of Ti50Ni40Co10 shape memory alloy. Moreover Topsis method implemented for the parametric optimization of wire electro discharge machining (WEDM). Pulse on time, Pulse off time, Servo voltage, wire speed and servo feed were considered as process parameters and productivity rate and surface quality (average roughness) were consider as output process parameters of WEDM. To see the effect of machining on the machined component EDX analysis has been carried out of optimal process parameters setting. 4.72 mm3 /min productivity rate and 1.26 µm average roughness was found at optimal combination of process parameters of WEDM. Moreover, during the EDX analysis Cu, Zn, O and C were noticed on the machined surface including the parent material.
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Evaluation of South African Chromite sand sintering behaviour

- Kabasele Jonathan K, Nyembwe Didier K, Ochonogor Franklin

  • Authors: Kabasele Jonathan K , Nyembwe Didier K , Ochonogor Franklin
  • Date: 2020
  • Subjects: Sintering temperature , Turbidity , Silica content
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/410552 , uj:34458 , Citation: Kabasele J. K., Nyembwe, D. K., Ochonogor F.: Evaluation of South African Chromite sand sintering behaviour.
  • Description: Abstract: This research was conducted on 6 different supplies of South African chromite sand samples: Lil sales, Insimbi, S11594, Rand York, Pentagon and Mineral Loy. The aim of the experiment was to determine the foundry properties of chromite sand that affect its sintering temperature. Three foundry properties of chromite sand were studied: turbidity or the amount of impurities, the percentage of fine particles and percentage of silica content. The approach selected to perform the sintering test was the VDG procedure 26 from the German foundry association. The test observes the sintering behaviour of chromite sand over a range of temperature and is able to identify its sintering temperature. Using simple linear regression analysis, it was concluded that the presence of impurities, high silica content and fine particles decreases significantly the sintering temperature of chromite sand which contributed to an increase in the occurrence of casting defects.
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Machinability studies on abrasive water jet machining of low alloy steel for different thickness

- Khan, Adam M., Gupta, Kapil

  • Authors: Khan, Adam M. , Gupta, Kapil
  • Date: 2020
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/411264 , uj:34553 , Citation: M Adam Khan and Kapil Gupta 2020 IOP Conf. Ser.: Mater. Sci. Eng. 709 044099 , DOI: 10.1088/1757-899X/709/4/044099
  • Description: Abstract: This paper reports some results of experimental investigation conducted on abrasive water jet machining (AWJM) of medium carbon low alloy (EN24) steel. EN24 steel samples of different thickness have been machined at various combinations of AWJM parameters. Three important AWJM parameters namely water jet pressure, nozzle traverse speed, and stand-off distance have been varied at three levels each. Three important responses i.e. material removal rate, kerf wall inclination, and surface roughness (average roughness) have been considered as the machinability indicators. The variation of these machinability indicators with a range of thicknesses of EN24 steel samples has been investigated. It is found that AWJM is capable to machine EN24 steel at very high MRR even at the increased thickness. But, surface finish deterioration is prominent with sample having higher thickness. Moreover, nozzle traverse speed is identified as the most significant parameter. It is concluded that the jet pressure of 240MPa with traverse speed of 20mm/min can produce good machinability for AWJM of EN24 Steel.
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On productivity of abrasive water jet machining for miniature gear manufacturing

- Gupta, Kapil

  • Authors: Gupta, Kapil
  • Date: 2020
  • Subjects: Quality , Productivity , Sustainability
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/411272 , uj:34554 , Citation: Kapil Gupta 2020 IOP Conf. Ser.: Mater. Sci. Eng. 709 044100 , DOI:10.1088/1757-899X/709/4/044100
  • Description: Abstract: Quality, productivity, and sustainability are three major indicators to evaluate the performance of any manufacturing process. Abrasive water jet machining (AWJM), which is an advanced or nonconventional machining process possess numerous benefits over conventional and other advanced processes for manufacturing of precision engineering components. Material removal rate directly indicates about the process productivity, and often finds contradictory to quality and sustainability. This paper reports the productivity of AWJM process while manufacturing miniature gears of brass. It is a part of experimental investigation conducted to manufacture high quality miniature brass gears using AWJM process. Taguchi L9 orthogonal array based experimental study where a total of nine experiments with two replicates each was conducted to evaluate the effect of AWJM parameters on miniature gear quality, process productivity and sustainability. AWJM parameters were optimized to enhance material removal rate and an optimum value of 18.80 mm3 /min was obtained. Furthermore, AWJM was identified as a superior to conventional machining processes for manufacturing of miniature gears.
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Optimization of the surface quality in illing achine using PVC composite plate

- Ahirwar, Yashwant, Soni, Hargovind, Mashinini, P.M.

Past and present spatial precipitation variability in the upper middle catchment of the Olifants River basin

- Nkhonjera, German K., Dinka, Megersa O.

  • Authors: Nkhonjera, German K. , Dinka, Megersa O.
  • Date: 2020
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/411208 , uj:34546 , Citation: German K. Nkhonjera and Megersa O. Dinka 2020 IOP Conf. Ser.: Earth Environ. Sci. 467 012212 , DOI :10.1088/1755-1315/467/1/012212
  • Description: Abstract: Within the context of catchment hydrology, using the Soil and Water Assessment Tool (SWAT) model, this paper attempts to assess the past and present spatial precipitation variability in the upper middle catchment (UMC) of the Olifants River basin. The study shows a strong decreasing trend of east-to-west direction of spatial precipitation with most rainfall concentrated in the eastern part of the area. Within the western part of the UMC, we also noted another decreasing trend of precipitation from south to north with northern areas of the study area receiving the least amount of rainfall. This localized spatial precipitation variability in the area, from past and present, underlines the importance of studies targeting localized areas within a larger and wider river basin like the Olifants where such variations could otherwise been overlooked.
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A Block Diagonal Markov model for indoor software-defined power line communication

- Familua, Ayokunle Damilola

  • Authors: Familua, Ayokunle Damilola
  • Date: 2019
  • Subjects: Baum-Welch Algorithm , Block Diagonal Markov Model , PLC
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/398582 , uj:33188 , Citation: Familua, A.D. 2019. A Block Diagonal Markov model for indoor software-defined power line communication.
  • Description: Abstract: A Semi-Hidden Markov Model (SHMM) for bursty error channels is defined by a state transition probability matrix A, a prior probability vector Π, and the state dependent output symbol error probability matrix B. Several processes are utilized for estimating A, Π and B from a given empirically obtained or simulated error sequence. However, despite placing some restrictions on the underlying Markov model structure, we still have a computationally intensive estimation procedure, especially given a large error sequence containing long burst of identical symbols. Thus, in this paper, we utilize under some moderate assumptions, a Markov model with random state transition matrix A equivalent to a unique Block Diagonal Markov model with state transition matrix Λ to model an indoor software- defined power line communication system. A computationally efficient modified Baum-Welch algorithm for estimation of Λ given an experimentally obtained error sequence from the indoor PLC channel is utilized. Resulting Equivalent Block Diagonal Markov models assist designers to accelerate and facilitate the procedure of novel PLC systems design and evaluation.
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A comparison of strategies for missing values in data on machine learning classification algorithms

- Makaba, T., Dogo, E. M.

A correlation between nano and micro-hardness properties of TiN nanoparticles strengthened SAF 2205

- Oke, S R, Ige, O O, Falodun, O E, Obadele, B A, Olubambi, P A, Shongwe, M B, Mphahlele, M R

A cost-effective low-voltage moulded-case circuit breaker test jig

- Venter, Johan, Van Niekerk, Daniel Rodrigues

  • Authors: Venter, Johan , Van Niekerk, Daniel Rodrigues
  • Date: 2019
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/409666 , uj:34351 , Citation: Venter, J., Van Niekerk, D.R. 2019: A cost-effective low-voltage moulded-case circuit breaker test jig.
  • Description: Abstract: A practical method to test post-manufactured mechanical thermal and thermal-magnetic low voltage Moulded Case Circuit Breakers (MCCBs) is presented in this paper. Many standards pertaining to the ratings of low voltage MCCBs exist, but little literature exists on how to verify its specified rating post-manufacturing. In this work, a variable voltage over fixed cable and MCCB switch contact resistance test method is used to verify ratings. This method uses two variable transformers driven by two separate stepper motors controlled by a microcontroller with a final step-down toroid transformer. To measure the circuit breaker, trip current level an accurate Hall-Effect current sensor was used and the trip time is determined by a microcontroller-based peripheral timer. Testing was conducted on four different types of circuit breakers, namely: C6, D10, C16, and C20 in order to verify the test jig functionality with good results.
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A country’s growth-aspiring entrepreneurship : a three-way interaction between corporate taxation, venture capital availability and social legitimacy

- Reddy, Colin David

A factor analysis of transportation infrastructure feasibility study factors : a study among built environment professionals in South Africa

- Okoro, Chioma Sylvia, Musonda, Innocent, Agumba, Justus Ngala

A factor analysis of transportation infrastructure feasibility study factors : a study among built environment professionals in South Africa

- Okoro, Chioma Sylvia, Musonda, Innocent, Agumba, Justus Ngala

A model for efficient consumption of electricity in residential buildings

- Olatunji, Obafemi O, Ayo, Olayinka O, Akinlabi, Stephen A, Ishola, Felix, Madushele N, Adedeji, Paul A

A novel approach for the identification of influential node in an electric power grid

- Adebayo, Isaiah G., Sun, Yanxia

  • Authors: Adebayo, Isaiah G. , Sun, Yanxia
  • Date: 2019
  • Subjects: Influential node, Power network, Centrality measure
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/396397 , uj:32910 , Citation : Adebayo, I.G. 2019. A novel approach for the identification of influential node in an electric power grid @ Sun, Y.
  • Description: Abstract : The continuous occurrence of blackouts due to cascading failures and voltage instability which has the effect of damaging several components within the grid has of recent been traced to sudden disconnection of influential node in a power network. How to identify this node has become a crucial issue to power system utilities. In this paper, an approach which is based on the network topological properties of an electric power system is investigated for the identification of influential node in a power network. First, we established a matrix which capture information between an electrical interconnection that exist between load to load nodes in a power network. Next, the suggested network structurally based eigenvector centrality measure (NSECM) is formulated based on the established matrix. A comparison analysis with a conventional eigenvector centrality measure is also performed to determine the significance of the proposed method. The effectiveness of all the approaches presented is tested on both practical 26-bus and the IEEE 14-bus power systems. Results obtained show that identification of influential node in a power network is better done using the NSECM method as it reduces the computational burden.
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A recipe for national innovate entrepreneurial activity : finance and industry with a dose of self-confidence

- Reddy, C.D.

A reverse order life cycle approach to enhance systems engineering education at undergraduate level

- Meyer, J., Von Solms, S.

  • Authors: Meyer, J. , Von Solms, S.
  • Date: 2019
  • Subjects: Engineering education , Industry 4.0 , Reverse Life Cycle
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/404177 , uj:33885 , Citation: Meyer, J. & Von Solms, S. 2019. A reverse order life cycle approach to enhance systems engineering education at undergraduate level.
  • Description: Abstract: The advances of Industry 4.0 lead the transition into the era of complex systems, requiring systems solutions for complex problems, increasing the interest in the development of systems engineers. However, traditional systems thinking may lose its effectiveness in this new context, which leads to a challenge in systems engineering education. This research aims to better prepare systems engineers of the future by addressing the disconnect which exist between systems engineering education at undergraduate level, and the real-life complex systems seen in society today though the implementation of a reverse order life cycle approach. By following the reverse order life cycle approach with a familiar electrical appliance, such as the electric kettle, in the classroom, undergraduate systems engineering students were able to gain the necessary insight and understanding regarding the dynamics of complex systems the underlying systems engineering concepts.
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A review of communication technologies for efficient communication in the smart grid of the 4IR era

- Damilola, Ayokunle

  • Authors: Damilola, Ayokunle
  • Date: 2019
  • Subjects: Power Line Communication , Wired Communication Technologies , Wireless Communication Technologies
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/398543 , uj:33184 , Citation: Damilola, A. 2019. A review of communication technologies for efficient communication in the smart grid of the 4IR era.
  • Description: The conventional radial topology of the electrical power system poses a less reliable power system should there be system failure, thus, resulting into the disruption of electrical power delivery in the network. Increased security threats, theft of electrical energy, and current technological advancements in the information and communications technology (ICT) are factors that ushered in the advent of Smart Grid (SG). The SG, is a modernized electrical grid that utilizes digital or analog ICT to collect and take action on information in an automated fashion to enhance the reliability, efficiency, economics, and sustainability of electricity generation and distribution. For accurate functionality, the SG system has different subsystems, amongst which is the communication subsystem. This subsystem plays an essential role in providing high-speed, reliable and secured real-time transfer and communication of data amongst system devices and other sub-systems interconnected in the SG network so as to effectively and intelligently manage the complex power systems. This paper reviews communication technologies (wired and wireless), that are strong prospects for deployment in a SG, while also highlighting their benefits and challenges.
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A Review of Critical Project Management Techniques to Enhance Construction SMEs Project Performance

- Emere, Chijioke, Musonda, Innocent, Okoro, Chioma

  • Authors: Emere, Chijioke , Musonda, Innocent , Okoro, Chioma
  • Date: 2019
  • Subjects: Construction SMEs , Project performance , Project management techniques
  • Language: English
  • Type: Conference proceedings
  • Identifier: http://hdl.handle.net/10210/396774 , uj:32951 , Citation: Emere, C., Musonda, I. & Okoro, C. 2019. A Review of Critical Project Management Techniques to Enhance Construction SMEs Project Performance.
  • Description: Abstract: Performance is linked with implementation of project management techniques. Lit- erature suggests that problems such as inefficiency, poor budgetary issues, improper planning, scheduling and control in projects execution are associated with inadequate implementation of the essential techniques for meeting project deliverables. These shortcomings are prevalent among Small and Medium Enterprises (SMEs) in the developing countries including South Af- rica. Hence, the primary objective of this paper is to review the critical project management tech- niques for the improvement of construction project performance especially among SMEs in South Africa. The study is based on previous literature on construction SMEs project performance as well as project management techniques implementation. The literature review centered on both international and South African context. The study revealed that critical path method, work breakdown structure, and earned value management analysis were the most occurring project management techniques from the sampled literature. Findings from this study are envisaged to be beneficial to construction stakeholders in developing relevant project management techniques to improve the performance of SMEs.
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