Remanufacturing production planning considering quality cost and demand substitution

Aiming to minimize the total production costs in a single planning period, a nonlinear integer programming model for remanufacturing production plans is established considering the influence of different qualities of returns acting on production cost. Three different remanufacturing and discarding strategies are adopted to analyze the change rules of the total production costs. The results returns is greater than indicate that when the number of remanufacturing returns of high the demand, preferentially quality and discarding those of low quality can bring better economic benefits due to manufacturing cost reduction. However, when the number of returns is smaller than the demand, there is no need to consider grading of returns, whereas new demand of remanufacturing. parts are required to satisfy the

VPLS Based Quality and Cost Control for Tennessee Eastman Process

Product quality and operation cost control obtain increasing emphases in modern chemical system engineering. To improve the fault detection power of the partial least square (PLS) method for quality control, a new QRPV statistic is proposed in terms of the VP (variable importance in projection) indices of monitored process variables, which is significantly advanced over and different from the conventional Q statistic. QRPV is calculated only by the residuals of the remarkable process variables (RPVs). Therefore, it is the dominant relation between quality and RPV not all process variables (as in the case of the conventional PLS) that is monitored by this new VP-PLS (VPLS) method. The combination of QRPV and T2 statistics is applied to the quality and cost control of the Tennessee Eastman (TE) process, and weak faults can be detected as quickly as possible. Consequently, the product quality of TE process is guaranteed and operation costs are reduced.

Comparison on Commercial Application of Two Types of C_8 Aromatics Isomerization Catalysts

The results of commercial application of two types of C_8 aromatics isomerization catalysts under different feed conditions were compared to gain an insight in the techno-economical basis for selecting proper technological route at the plant.The comparison reveals differences in every aspect of feed consumption,unit capacity,product output,product distribution,and unit process parameters depending upon which catalyst type is adopted by the integrated PX complex.The type of aromatics isomerization catalyst has its influence on the plant scale,the construction cost,the process unit capacity and the product cost,with the magnitude of its impact varying with changing feed conditions.

Development of a group support system to support collaborative works in value management workshops

Value Management (VM) is a rigorous and systematic approach to improve the value and optimise the overall cost of a facility. It identifies opportunities to remove unnecessary costs while assuring that quality, reliability, performance, and other critical factors will meet or exceed the customers’ expectations. It has been widely used in the construction industry in a number of countries. A recent survey, however, revealed several problems that hinder the wider use of this methodology in the industry. To overcome these problems, a feasibility study has been conducted to investigate whether or not a Group Support System (GSS) can support collaborative works in VM workshops. This paper introduces the development and structure of a prototype GSS which is designed to support the collaborative works of stakeholders in VM workshops. It begins with an introduction to the conceptual GSS framework and job plan, illustrating what GSS supports can be provided to VM workshops. This is followed by a detailed description of the GSS prototype system to demonstrate how these supports can be performed as an integrated computer system. The testing of the system is also discussed. The research findings provide strong evidence in supporting the notion of using GSS to improve VM implementation. The information support of GSS has been ranked to be the most useful GSS functions and most of the practitioners interviewed are highly interested in applying GSS to support VM workshops in the future.

Multi-objective optimization of rolling schedule based on cost function for tandem cold mill

In terms of tandem cold mill productivity and product quality, a multi-objective optimization model of rolling schedule based on cost fimction was proposed to determine the stand reductions, inter-stand tensions and rolling speeds for a specified product. The proposed schedule optimization model consists of several single cost fi.mctions, which take rolling force, motor power, inter-stand tension and stand reduction into consideration. The cost function, which can evaluate how far the rolling parameters are from the ideal values, was minimized using the Nelder-Mead simplex method. The proposed rolling schedule optimization method has been applied successfully to the 5-stand tandem cold mill in Tangsteel, and the results from a case study show that the proposed method is superior to those based on empirical formulae.

Study of Synthetic Process of Vitamin C

[ Objective] The aim was to find optimum reaction conditions for synthetic process of Vitamin C. [ Method] Vitamin C sodium was used as raw material to prepare vitamin C through acidification, separation, desalination, recovery and purification. The impact of reaction time, tempera-ture, feedstock molar ratio and water content on the yield of vitamin C were investigated in the experiment. [Result] The optimum reaction condi- tions for synthetic process of Vitamin C were as follows： in the acidification test, reaction time 120 min, temperature 20 -30 ℃, the molar ratio be-tween hydrochloric acid and Vitamin C sodium 1 ： 1 and water content 41.0%. Under the above condition, the purity and yield of vitamin C reach 99.80% and 94.74% respectively. [Conclusion] The process can decrease consumption, enhance quality and recover of the product, improve the environmental pollution, shorten processing periods and reduce production cost. Thus, the process is suitable for industrialization. Key words Vitamin C; Vitamin C sodium; Acidification; China

An Empirical Study on the Relationship Between China's Maize Price and Maize Import and Export Trade

Based on the time series of China’s maize trade and domestic maize price,the article analyzes the relationship between domestic maize price and China’s maize international trade by using empirical methods.The results show that there is a connection between domestic maize prices and China's maize international trade,but the link is not very close.Domestic maize price is the cause of China’s maize international trade change,but its impact is very limited;China's maize international trade also can make some difference on the domestic maize price.Based on the results of research,the article brings three suggestion and expectation to adjust China’s maize international trade and the cost control reasonably in order to stabilize domestic maize price and maize yield,and to protect domestic grain security.

Prospect of the Seawater Desalination Technology

This article classifies the seawater desalination technology into four types of hot method, membrane method, electric field method and solvent method. Electric field method and solvent method still remain experimental stage, while hot method and membrane method have been realized in commercialization but are difficult to be promoted. The problem lies in high water-producing cost. It is difficult for membrane method seawater desalination technology to reduce the water-producing cost. The heat utilization efficiency is not high for the current hot method seawater desalination technology and there is large amount of heat lost with the emission of concentrated seawater. The new hot method seawater desalination technology and new solar-powered seawater desalination technology can divide the seawater into fresh water and solid salt without any emission of concentrated seawater so that the heat utilization efficiency can reach theoretical limit to multiply reduce the water-producing cost. They will become the mainstream technology for seawater desalination and can totally eliminate the global water crisis.

High χ polystyrene-b-polycarbonate for next generation lithography

Over the past half century,the semiconductor chips have deeply influenced our everyday life through increasingly sophisticated electronic products.The central driving force underlying the remarkable evolution in semiconductor industry is Moore’s Law,nowadays referring to a doubling of transistor counts per chip every 18 months.Sustaining Moore’s Law is economically beneficial;while the manufacturing cost per chip has been held constant,

A maximum a posteriori super resolution algorithm based on multidimensional Lorentzian distribution

This paper presents a threshold-free maximum a posteriori (MAP) super resolution (SR) algorithm to reconstruct high resolution (HR) images with sharp edges. The joint distribution of directional edge images is modeled as a multidimensional Lorentzian (MDL) function and regarded as a new image prior. This model makes full use of gradient information to restrict the solution space and yields an edge-preserving SR algorithm. The Lorentzian parameters in the cost function are replaced with a tunable variable, and graduated nonconvexity (GNC) optimization is used to guarantee that the proposed multidimensional Lorentzian SR (MDLSR) algorithm converges to the global minimum. Simulation results show the effectiveness of the MDLSR algorithm as well as its superiority over conventional SR methods.