The Office of the Leading Team of Product Quality and Food Safety of the State Council held its third meeting on September 10. Li Changjiang, Minister of AQSIQ, presided over the meeting, and Pu Changcheng, Deputy... The Office of the Leading Team of Product Quality and Food Safety of the State Council held its third meeting on September 10. Li Changjiang, Minister of AQSIQ, presided over the meeting, and Pu Changcheng, Deputy Director of AQSIQ, also attended.……展开更多
Firstly an overview of the potential impact on work-in-process (WIP) and lead time is provided when transfer lot sizes are undifferentiated from processing lot sizes. Simple performance examples are compared to thos...Firstly an overview of the potential impact on work-in-process (WIP) and lead time is provided when transfer lot sizes are undifferentiated from processing lot sizes. Simple performance examples are compared to those from a shop with one-piece transfer lots. Next, a mathematical programming model for minimizing lead time in the mixed-model job shop is presented, in which one-piece transfer lots are used. Key factors affecting lead time are found by analyzing the sum of the longest setup time of individual items among the shared processes (SLST) and the longest processing time of individual items among processes (LPT). And lead time can be minimized by cutting down the SLST and LPT. Reduction of the SLST is described as a traveling salesman problem (TSP), and the minimum of the SLST is solved through job shop scheduling. Removing the bottleneck and leveling the production line optimize the LPT. If the number of items produced is small, the routings are relatively short, and items and facilities are changed infrequently, the optimal schedule will remain valid. Finally a brief example serves to illustrate the method.展开更多
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
The production of π^(0),η,andφin the most central(0%-5%)Xe+Xe collisions at √s_(NN)=5.44 TeV is investigated in the framework of the perturbative QCD(pQCD)improved parton model at an accuracy of next-toleading ord...The production of π^(0),η,andφin the most central(0%-5%)Xe+Xe collisions at √s_(NN)=5.44 TeV is investigated in the framework of the perturbative QCD(pQCD)improved parton model at an accuracy of next-toleading order(NLO).The jet quenching effect is effectively incorporated by medium-modified fragmentation functions via the higher-twist approach.Predictions of the nuclear modification factors of π^(0),η,and φ as functions of the transverse momentum p_(T) are made with the jet transport parameter q_(0),which is extracted from the available experimental data of charged hadrons provided by ALICE and CMS.The particle ratios η/π^(0),φ/π^(0) as functions of p_(T) in Xe+Xe collisions at √s_(NN)=5.44 TeV as well as in 0%-5% Pb+Pb collisions at √s_(NN)=5.02 TeV are also presented.The numerical simulations of the scaled ratios of charged hadron production in the Xe+Xe 5.44 TeV system over those in the Pb+Pb 5.02 TeV system give a good description of the CMS data,and the scaled ratios of π^(0),η,and φ production coincide with the curve of charged hadron production.展开更多
文摘 The Office of the Leading Team of Product Quality and Food Safety of the State Council held its third meeting on September 10. Li Changjiang, Minister of AQSIQ, presided over the meeting, and Pu Changcheng, Deputy Director of AQSIQ, also attended.……
基金This project is supported by National Natural Science Foundation of China (No.70372062, No.70572044)Program for New Century Excellent Talents in University of China (No.NCET-04-0240).
文摘Firstly an overview of the potential impact on work-in-process (WIP) and lead time is provided when transfer lot sizes are undifferentiated from processing lot sizes. Simple performance examples are compared to those from a shop with one-piece transfer lots. Next, a mathematical programming model for minimizing lead time in the mixed-model job shop is presented, in which one-piece transfer lots are used. Key factors affecting lead time are found by analyzing the sum of the longest setup time of individual items among the shared processes (SLST) and the longest processing time of individual items among processes (LPT). And lead time can be minimized by cutting down the SLST and LPT. Reduction of the SLST is described as a traveling salesman problem (TSP), and the minimum of the SLST is solved through job shop scheduling. Removing the bottleneck and leveling the production line optimize the LPT. If the number of items produced is small, the routings are relatively short, and items and facilities are changed infrequently, the optimal schedule will remain valid. Finally a brief example serves to illustrate the method.
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.
基金Supported by the Guangdong Major Project of Basic and Applied Basic Research(2020B0301030008)the Natural Science Foundation of China with Project(11935007,11805167)。
文摘The production of π^(0),η,andφin the most central(0%-5%)Xe+Xe collisions at √s_(NN)=5.44 TeV is investigated in the framework of the perturbative QCD(pQCD)improved parton model at an accuracy of next-toleading order(NLO).The jet quenching effect is effectively incorporated by medium-modified fragmentation functions via the higher-twist approach.Predictions of the nuclear modification factors of π^(0),η,and φ as functions of the transverse momentum p_(T) are made with the jet transport parameter q_(0),which is extracted from the available experimental data of charged hadrons provided by ALICE and CMS.The particle ratios η/π^(0),φ/π^(0) as functions of p_(T) in Xe+Xe collisions at √s_(NN)=5.44 TeV as well as in 0%-5% Pb+Pb collisions at √s_(NN)=5.02 TeV are also presented.The numerical simulations of the scaled ratios of charged hadron production in the Xe+Xe 5.44 TeV system over those in the Pb+Pb 5.02 TeV system give a good description of the CMS data,and the scaled ratios of π^(0),η,and φ production coincide with the curve of charged hadron production.