External Supply System Research Articles

Coordination Performance Evaluation of Supply Logistics in JIT Environment

In JIT assembly system, any supplier’s postponement of delivery or incorrect delivery quantity will result in the manufacturer’s incapability of assembling on schedule, which will not only damage the interests of other suppliers but also jeopardize the interests of enterprises and reduce the competitiveness of the supply chain. In this article, coordination of the upstream supply logistics from internal and external aspects is taken as the research object. In external supply system, three aspects of cost, quality and time are used to evaluate the coordination of supply logistics in JIT environment. From the internal aspect, reliability, flexibility, responsiveness, customer service and system suitability are selected for the performance evaluation. The eight indexes construct an index system and each performance index is described and analyzed. Finally, Analytic Hierarchy Process is used to evaluate the coordinated performance of supply logistics in JIT environment. An example is provided, which illustrate the method used in this paper is feasible and meaningful.

Design of step dynamic voltage regulator for power quality enhancement

The design of step dynamic voltage regulator is considered for the purpose of restoring load voltage without incurring excessive phase angle shift. As a type of custom power device devoid of any significant energy-storage capability, the process of voltage restoration by the regulator has to depend on the power in-feed from an external supply system. As a consequence, the analysis shows that there are inherent limits imposed on the device for achieving successful voltage restoration. Pertinent expressions are derived which relate the limits to the parametric values describing the supply system and loads. When the expressions are used in conjunction with a proposed computational procedure, a method to determine suitable regulator design for the purpose of power quality enhancement is obtained.

Design of Step Dynamic Voltage Regulator for Power Quality Enhancement

The design of a step dynamic voltage regulator is considered for the purpose of restoring load voltage without incurring excessive phase angle shift. As a type of custom-power device devoid of any significant energy-storage capability, the process of voltage restoration by the regulator has to depend on the power in-feed from external supply system. As a consequence, the analysis shows that there are inherent limits imposed on the device for achieving successful voltage restoration. Pertinent expressions are derived which relate the limits to the parametric values describing the supply system and loads. When the expressions are used in conjunction with a proposed computational procedure, a method to determine suitable regulator design for the purpose of power quality enhancement is obtained.

Improved Method for Numerical Solutions of the General Incompressible Fluid Film Lubrication Problem

A numerical analysis for determining performance characteristics of hydrodynamic, hydrostatic, or hybrid bearings with arbitrary clearance distribution is presented. Solution of the Reynolds lubrication equation for incompressible fluids is achieved by formation of coefficient matrices that act upon column vectors of the pressures progressively from one boundary to the other without requiring an iterative scheme. Multiple recesses are handled by component solutions. The external supply system is included and solved for an arbitrary type of individual recess compensation and supply circuit network. Sample results are indicated.