Applied Mechanics and Materials Vol. 472

Abstract: Currently, boiler efficiency evaluation system is always established on the method of heat balance based on the first law of thermodynamics as the main indicator, it is imperfect. Using Exergy method, which is based on the first and the second law of thermodynamics, not only focus on energy consumption, but also take the useful energy utilization levels into account, combined with evaluation of environmental indicators, the evaluation index system is established for energy-efficient of boilers. Then, in view of the structural characteristics of the index system, using fuzzy comprehensive evaluation method evaluates the energy efficiency of boilers. Finally, by using this evaluation method, energy efficiency was studied.

Abstract: This paper approaches the microgrid concept from a systemic and cybernetics viewpoint, as a viable sustainable energy system (SES) for supplying electricity and heat to small, rural communities in Chile. As such the microgrid may be viewed as a complex adaptive system (CAS) when connected to the grid and operating without energy storage, only with the grid as back-up power source. From an exergy and homeostatic control (HC) standpoint, one may analyze the microgrid as a socio-technical CAS when it is coupled with a set of homes and also connected to the grid; capable of supplying close to 80% of the daily residential consumer needs on average. Thus, under these conditions homes may draw inexpensive renewable electricity and heat from the microgrid if they are thrifty and efficient in their energy consumption, and they may also consume from the utility grid, yet at an expensive price. Based on this an exergy and HC approach is proposed to develop such SES for rural and remote communities in Chile and South America, aiming to enhance energy efficiency (EE) and energy sustainability (ES). Under this scheme, renewable power (RP) being a scarce resource that must be managed efficientlyis supplied only to homes which comply with a specific criterion in an effort to curtail demand to ensure ES overtime. Simulation shows as expected that indeed certain criteria produce much better results than others in incentivizing thrifty, efficient energy consumption for small-size communities without the need for expensive and sometimes polluting and forbidden energy storage systems.

Abstract: Unidirectional circulation-type material handling system on a single loop with a shortcut is a typical and basic unit in a flexible manufacturing system (FMS). It is widely used in the FMSs. Superposition efficiency of the basic unit often determines the one of the whole system. In this system, a fleet of AGVs circulates along a loop with short-cut unidirectionally. After AGVs load jobs, jobs are sent to process at a processing station set along the path, and then unload at an unloading station. AGVs continue to circulate until all jobs are processed. The AGVs can't be overtaken except in the cross point. So it is difficult to avoid the interference between AGVs. Different scheduling rules have an important effect on the unidirectional circulation-type material handling system on a single loop with a shortcut. To decrease the interference and improve performance of the system, this paper makes a mathematical model of this system and put forward optimal scheduling rules. Experiment results show that the optimal rules can decrease the interference time and improve efficiency, so as to achieve the optimal performance.

Abstract: Quality of import goods is possibly not up to standard in letter of credit settlement. In order to control the quality of import goods and to prevent exporter from fraudulent credit, importer takes some of the most effective terms that will be considered as soft term fraud by exporter. This paper analyzed the reason for the existence of such risks, and proposed innovative ideas on how to effectively control the quality of import goods in letter of credit settlement. Letter of credit (hereinafter referred as L/C) settlement serves as a more effective, timely and safe transaction way for both sellers and buyer in international trade, but there is still the risk of fraud [. Fraud risk is the greatest one in letter of credit settlement. Buyers will attach great importance to the quality of import goods, but exporter fraud will lead import goods not up to standard. In order to prevent such a quality risk, the importer will set some terms in the L/C, but these terms may be considered as soft term fraud by exporter. Research of risk management in L/C settlement will help importer effectively control the quality of import goods, and promote the L/C settlement.

Abstract: The capability to damp sub-synchronous oscillations of single-phase TCSC, two-phase TCSC, three-phase TCSC is comparatively studied in this paper. SVR (Synchronous Voltage Reversal) is used as the control strategy of these three schemes. And IEEE first benchmark model is taken as the simulation example. Generator power, torques and LVUR (Line Voltage Unbalanced Voltage) are simulated. The results show that all the three schemes can effectively suppress SSO, but compared with single-phase and three-phase TCSC, the convergence rate of generator torques in the two-phase TCSC scheme is slower, thus its damping effect is worse, while single-phase and three-phase nearly has equal damping capacity. After the three-phase fault, the steady value of LVUR under three schemes can all meet the requirements of national standard in China. Through the comparison between these three schemes, it can be concluded that single-phase TCSC is a new structure which has great potential to apply to practical projects, but further theoretical analysis and much more simulation should be done to verify.

Abstract: In order to evaluate the energy-saving effect of Distributed Cooling System (DCS) analytically, the heat balance model of DCS in a TBS is established and then dynamic simulation is employed. The numeral results show that DCS has much better energy-saving effect than traditional air conditioning (AC) and the energy-saving effect is steady all year round.

Abstract: For evaluating the performance of combined heat and power district heating (CHP-DH) system, some thermodynamic indicators of CHP system, include energy efficiency, exergy efficiency, RPES and RAI, are introduced in this paper. Based on two condensed and heating dual purpose plants, the values of these indicators are calculated with different extraction ratio. The results show that RAI and RPES are more reasonable to be used to assess CHP-DH system and there is a minimum extraction ratio for each unit, which is 0.4 for given plants in this paper, to keep CHP-DH beneficial compared with separate heat and power (SHP) system. Besides, the minimum heat demand of CHP-DH system should be larger than the supplied heat correspond to minimum extraction ratio.

Abstract: Integrated construction technology is in developing quickly in Chinas civil engineering community. With its space saving and heat insulation properties, people both in cold and hot region both need the thin wall settled structure to avoid burning hot or extremely cold. This article proposed an innovative integrating construction technology that has gained more and more popularity in construction project by adoption of thin wall thermal insulation board. The detail of the anchorage of the structure surface and the board, bond together with a special nail, and the whole system was controlled by the fastening system. It is one type vertical integration strategy and will gain more competition advantages for the construction enterprises.

Abstract: This paper using data of China's Industrial Sector in 1996 -2010, selecting the stochastic frontier production function model, estimating the rate of change of total factor productivity in various industries, gets the level of technological progress in various industries. On this basis, domestic and foreign investment in 1996 -2010 data, were used based on the panel data model to study the impact of the level of domestic and foreign investment in industrial sectors of technological progress. The empirical results show that the industrial technological progress in the vast majority of the industry comes from domestic investment or foreign investment, the individual industry even at the same time by the dual effects of domestic and foreign investment, When the industry is characterized by high degree of market competition and foreign investment to domestic investment proportion is higher, technological progress is more inclined to come from domestic investment, the contrary is more inclined to come from foreign investment.

Abstract: This According to discount asset function and double convex portfolio, the attainability of the asset optimization was discussed under the market models with transaction costs,. By virtue of stochastic analysis and the maximal value properties confined in some convex region, the attainability of asset optimization was given under discount function form and corresponding to utility function and expectation of utility function in this paper.