Step-wise synthesis of work exchange networks involving heat integration based on the transshipment model

Due to the deterioration of serious energy dilemma,energy-conservation and emission–reduction have been the strategic target in the past decades,thus people have identified the vital importance of higher energy efficiency and the influence of lower carbon development.Since work exchange network is a significant part of energy recovery system,its optima design will have dramatically significant effect on energy consumption reduction in chemical process system.With an extension of the developed transshipment model in isothermal process,a novel step-wise methodology for synthesis of direct work exchange network(WEN)in adiabatic process involving heat integration is first proposed in this paper,where a nonlinear programming(NLP)model is formulated by regarding the minimum utility consumption as objective function and optimizing the initial WEN in accordance with the presented matching rules to get the optimized WEN configuration at first.Furthermore,we focus on the work exchange network synthesis with heat integration to attain the minimal total annual cost(TAC)with the introduction of heat-exchange equipment that is achieved by the following strategies in sequence:introducing heat-exchange equipment directly,adjusting the work quantity of the adjacent utility compressors or expanders,and approximating upper/lower pressure limits consequently to obtain considerable cost savings of expanders or compressors and work utility.Finally,a case taken from the literature is studied to illustrate the feasibility and effectiveness of the proposed method.

Making Efforts to Open up New Prospects for Jiangsu's Foreign Economic Work

The Eighth Five-year Plan period wasa fast growing period for Jiangsu’sforeign economic and technical co-operation. Guided by the policy of seizingopportunities, expanding the opening driveand promoting development, all the staff atthe provincial foreign economic front madeevery effort to fulfill the goal of the sus-tained, fast and healthy development in for-

Minister Wang Zhongyu on Economic and Trade Work in 1996

1996 is the first year of the 9th Five-Year Plan,a key year for the newstage of China’s economic system reform and economic development,said Mr.Wang Zhongyu,Minister of the State Economic and TradeCommission,at the national economic and trade conference recently.In1996,with the increase of economic efficiency as the core,attention shallbe paid to four aspects:identifying enterprise reform as the central linkof the economic system reform:taking the technological progress ofenterprises as the main way for the change of the economic growth mode:further strengthening the comprehensive coordination of economic operation:and improving enterprises’ economic performance by raising the productionand marketing rate.increasing the velocity of circulation of funds,improving product quality and reducing costs.

Economic“Activity-Silent”Synaptic Mechanisms of Working Memory

Working memory（WM）allows humans to hold necessary information in temporary storage and manipulate such information online for higher-order cognitive functions,such as language understanding,decision making,and problem solving.Since its first appearance in the science of psychology in the 1960s,many theories have sought to elucidate the nature of WM.The most accepted model is