The increasing customers＇ demands in terms of speed of service and reduced cost at higher quality has generated a new platform on which manufacturing companies compete. This heightened challenge is virtually driving ...The increasing customers＇ demands in terms of speed of service and reduced cost at higher quality has generated a new platform on which manufacturing companies compete. This heightened challenge is virtually driving all manufacturing companies to introducing lean manufacturing principles into their production systems. This paper focuses on the analysis of the current state mapping of a case study and then proposes a future state mapping to the company. The extruder 60 production line of Denki wires and cables limited, Akure, Nigeria was carefully evaluated. Data were collected from actual operators on the shop floor and feedbacks from the customers at the Gemba. Denki＇s extruder 60 production line production lead time was massively reduced from 38.42 days to 5.16 days with a 12.86% waste reduction. At the end, a practical way of implementing this aspect of lean manufacturing was suggested.展开更多
Broadband PLC （power line communication） technology is a main factor of the development of digital convergence in the indoor network. It uses the already existing power cable infrastructure for communication purpose...Broadband PLC （power line communication） technology is a main factor of the development of digital convergence in the indoor network. It uses the already existing power cable infrastructure for communication purposes. The EM （electromagnetic） field radiating from the cable could, however, disturb other communication systems, and thus should be evaluated. The MoM （method of moment） and the FEM （finite element method） have been studied to estimate the EVI field emitted from the power cable. However, the M oM is difficult to treat the dielectric material of the cable and the FEM is time consuming. This paperpresents a new approach to estimate the radiated EM fields caused by PLC sy stems from the CM current along the cable, based on the transmission line theory. The proposed model has the advantage of using the measured primary parameters of the cable. An experimental analysis of the EM radiation distribution is also presented. A comparison showed that the model results agree quite well with the measurements performed in this study.展开更多
Holistic tin-plating on the outer conductor is one of the key processes in the manufacture of semi-flexible coaxial cable, which is widely applied to the third generation (3G) mobile communication system. However, in ...Holistic tin-plating on the outer conductor is one of the key processes in the manufacture of semi-flexible coaxial cable, which is widely applied to the third generation (3G) mobile communication system. However, in the traditional horizontal tin-plating process, disadvantages such as the pinhole defects and low productivity effect cannot be avoided. In this paper, a vertical tin-plating process was proposed to reduce the pinhole defects and improve the tincoating quality. Compared with the traditional horizontal tin-plating process, the immersion length was reduced from 300-400 mm to 10-100 mm and the tin-plating time was reduced from 7 s to 3 s in the proposed method. The experimental results indicate that immersion length and time are key parameters for the tin-plating quality. With this new tin-plating process, the experimental results show that the pinhole defects can be eliminated effectively by controlling the immersion depth below 100 mm and tin-plating time at 3 s. The thickness of tin-coating increased from not more than 5 μm to 12.3 μm with the proposed vertical tin-plating process. Meanwhile, the thickness of the intermetallic compounds (IMCs) layer between the tin-coating and copper wires was reduced from 3.26 μm to 0.62 μm if the immersion time decreased from 30 s to 1 s. Besides, a self-developed flux, which possesses a boiling point or decomposed temperature of active components over 300℃, exhibits a better efficiency in reducing the pinhole formation.展开更多
An improved method to install high voltage cables into ducts using water flow is described. Instead of using a single pig, a number of （dividable） MultiPigs are mounted around the cable, exerting a distributed force...An improved method to install high voltage cables into ducts using water flow is described. Instead of using a single pig, a number of （dividable） MultiPigs are mounted around the cable, exerting a distributed force resulting from the equally shared pressure differences over each pig. Because the capstan effect is reduced, the installation lengths are increased considerably, while pulling forces on the cable remain small. The MultiPigs can also be used for FreeFloating, flowing cable lengths to any desired location, loose from the cable insertion equipment. This is especially of use in difficulty to reach （for cable drums and other equipment） places, e.g. tunnels.展开更多
In South Africa, electricity is supplied through thousands-of-kilometers of overhead power cables, which is owned by Eskom the national energy supplier. Currently monitoring of these overhead power cables are done by ...In South Africa, electricity is supplied through thousands-of-kilometers of overhead power cables, which is owned by Eskom the national energy supplier. Currently monitoring of these overhead power cables are done by means of helicopter inspection flights and foot patrols, which are infrequent and expensive. In this paper, the authors present the design of a prototype power line crawler （inspection robot） for the monitoring of these overhead power lines in South Africa. The designed prototype power line crawler is capable of driving on the wire, balancing on the wire and is capable of maneuvering past certain obstacles found on the overhead power cables. The prototype power line crawler is designed to host a monitoring system that monitors the power line as the inspection robot drives on it. Various experimental tests were performed and are presented in this paper, showing the capability of performing these tasks. This prototype inspection robot ensures a platform for future development in this area.展开更多
A cable circuit of a substation in the United Kingdom showed high level of PD activities during a survey using hand hold PD testing equipment. The authors were invited to carry out on-site PD testing experiment to fur...A cable circuit of a substation in the United Kingdom showed high level of PD activities during a survey using hand hold PD testing equipment. The authors were invited to carry out on-site PD testing experiment to further diagnose and locate the potential problem of the cable system. This paper presents the experience of the present authors carrying out the cable test. Following a brief introduction to the experiment equipments and physical connections, the paper analyses the data collected from the testing, including PD pulse shape analysis, frequency spectrum analysis and phase resolved PD pattern analysis. Associated with PD propagation direction identification, PD source diagnosis and localisation was made. Four different types of sensors, which were adapted during the testing, are shown to have different frequency bandwidths and performed differently. Aider comparing the parameters of the sensor and the PD signals detected by individual sensor, optimal PD monitoring bandwidth for cable system is suggested.展开更多
Three "double-cable" conjugated polymers with thienopyrroledione-based backbone and perylene bisimide as side units were designed as electron acceptor for polymer-polymer solar cells. The polymers show broad...Three "double-cable" conjugated polymers with thienopyrroledione-based backbone and perylene bisimide as side units were designed as electron acceptor for polymer-polymer solar cells. The polymers show broad absorption spectra and low-lying frontier energy levels due to both aromatic backbone and side units. The new double-cable polymers can be used as electron acceptor to combine with several electron donors, in which power conversion efficiencies above 3% could be achieved.展开更多
文摘The increasing customers＇ demands in terms of speed of service and reduced cost at higher quality has generated a new platform on which manufacturing companies compete. This heightened challenge is virtually driving all manufacturing companies to introducing lean manufacturing principles into their production systems. This paper focuses on the analysis of the current state mapping of a case study and then proposes a future state mapping to the company. The extruder 60 production line of Denki wires and cables limited, Akure, Nigeria was carefully evaluated. Data were collected from actual operators on the shop floor and feedbacks from the customers at the Gemba. Denki＇s extruder 60 production line production lead time was massively reduced from 38.42 days to 5.16 days with a 12.86% waste reduction. At the end, a practical way of implementing this aspect of lean manufacturing was suggested.
文摘Broadband PLC （power line communication） technology is a main factor of the development of digital convergence in the indoor network. It uses the already existing power cable infrastructure for communication purposes. The EM （electromagnetic） field radiating from the cable could, however, disturb other communication systems, and thus should be evaluated. The MoM （method of moment） and the FEM （finite element method） have been studied to estimate the EVI field emitted from the power cable. However, the M oM is difficult to treat the dielectric material of the cable and the FEM is time consuming. This paperpresents a new approach to estimate the radiated EM fields caused by PLC sy stems from the CM current along the cable, based on the transmission line theory. The proposed model has the advantage of using the measured primary parameters of the cable. An experimental analysis of the EM radiation distribution is also presented. A comparison showed that the model results agree quite well with the measurements performed in this study.
基金Supported by Science and Technology Support Project of Tianjin Science and Technology Commission (No.10ZCKFGX3500)
文摘Holistic tin-plating on the outer conductor is one of the key processes in the manufacture of semi-flexible coaxial cable, which is widely applied to the third generation (3G) mobile communication system. However, in the traditional horizontal tin-plating process, disadvantages such as the pinhole defects and low productivity effect cannot be avoided. In this paper, a vertical tin-plating process was proposed to reduce the pinhole defects and improve the tincoating quality. Compared with the traditional horizontal tin-plating process, the immersion length was reduced from 300-400 mm to 10-100 mm and the tin-plating time was reduced from 7 s to 3 s in the proposed method. The experimental results indicate that immersion length and time are key parameters for the tin-plating quality. With this new tin-plating process, the experimental results show that the pinhole defects can be eliminated effectively by controlling the immersion depth below 100 mm and tin-plating time at 3 s. The thickness of tin-coating increased from not more than 5 μm to 12.3 μm with the proposed vertical tin-plating process. Meanwhile, the thickness of the intermetallic compounds (IMCs) layer between the tin-coating and copper wires was reduced from 3.26 μm to 0.62 μm if the immersion time decreased from 30 s to 1 s. Besides, a self-developed flux, which possesses a boiling point or decomposed temperature of active components over 300℃, exhibits a better efficiency in reducing the pinhole formation.
文摘An improved method to install high voltage cables into ducts using water flow is described. Instead of using a single pig, a number of （dividable） MultiPigs are mounted around the cable, exerting a distributed force resulting from the equally shared pressure differences over each pig. Because the capstan effect is reduced, the installation lengths are increased considerably, while pulling forces on the cable remain small. The MultiPigs can also be used for FreeFloating, flowing cable lengths to any desired location, loose from the cable insertion equipment. This is especially of use in difficulty to reach （for cable drums and other equipment） places, e.g. tunnels.
文摘In South Africa, electricity is supplied through thousands-of-kilometers of overhead power cables, which is owned by Eskom the national energy supplier. Currently monitoring of these overhead power cables are done by means of helicopter inspection flights and foot patrols, which are infrequent and expensive. In this paper, the authors present the design of a prototype power line crawler （inspection robot） for the monitoring of these overhead power lines in South Africa. The designed prototype power line crawler is capable of driving on the wire, balancing on the wire and is capable of maneuvering past certain obstacles found on the overhead power cables. The prototype power line crawler is designed to host a monitoring system that monitors the power line as the inspection robot drives on it. Various experimental tests were performed and are presented in this paper, showing the capability of performing these tasks. This prototype inspection robot ensures a platform for future development in this area.
文摘A cable circuit of a substation in the United Kingdom showed high level of PD activities during a survey using hand hold PD testing equipment. The authors were invited to carry out on-site PD testing experiment to further diagnose and locate the potential problem of the cable system. This paper presents the experience of the present authors carrying out the cable test. Following a brief introduction to the experiment equipments and physical connections, the paper analyses the data collected from the testing, including PD pulse shape analysis, frequency spectrum analysis and phase resolved PD pattern analysis. Associated with PD propagation direction identification, PD source diagnosis and localisation was made. Four different types of sensors, which were adapted during the testing, are shown to have different frequency bandwidths and performed differently. Aider comparing the parameters of the sensor and the PD signals detected by individual sensor, optimal PD monitoring bandwidth for cable system is suggested.
基金supported by the National Key R&D Program of China(2017YFA0204702)the National Natural Science Foundation of China(51773207,21574138,51603209,91633301)+3 种基金the Strategic Priority Research Program of the Chinese Academy of Sciences(XDB12030200)Open Research Fund of State Key Laboratory of Polymer Physics and Chemistry,Changchun Institute of Applied Chemistry of Chinese Academy of Sciencesthe Recruitment Program of Global Youth Experts of Chinathe Director,Office of Science,Office of Basic Energy Sciences,of the US Department of Energy(DE-AC02-05CH11231)
文摘Three "double-cable" conjugated polymers with thienopyrroledione-based backbone and perylene bisimide as side units were designed as electron acceptor for polymer-polymer solar cells. The polymers show broad absorption spectra and low-lying frontier energy levels due to both aromatic backbone and side units. The new double-cable polymers can be used as electron acceptor to combine with several electron donors, in which power conversion efficiencies above 3% could be achieved.
