Advanced Materials Research Vols. 347-353

Abstract: This paper presents an algorithm for two-stage homogenous strip patterns for rectangular pieces. The algorithm is appropriate for the shearing and punching process. It proposes the two-stage homogenous strip patterns that can be cut into homogenous strips in two stages, with another two stages being required to cut the strips into pieces. Firstly vertical cuts divide the stock sheet into segments, and then horizontal cuts divide the segments into homogenous strips. A homogenous strip contains pieces of the same type. The algorithm uses a dynamic programming recursion to determine the strip layout on each segment, solves knapsack problems to obtain the segment layout on the sheet. The algorithm is tested through benchmark problems, and compares with two famous algorithms. The pattern value and the computation speed of this paper’s algorithm are better than that of the classic two-stage algorithm. What’s more, this paper’s algorithm can give solutions very close to optimality.

Abstract: A new type of rotary Stirling engine for exhaust energy recovery is introduced in this paper. This engine is constructed by two eccentric cylinders with displaced centers. The space between these two circles is divided into four chambers. The outside cylinder is stationary while the inside cylinder rotates at a constant speed. The volume of each chamber would vary during the rotation. Part of the wall of the outside cylinder in the circumferential direction is heated with hot gas and the other part of the wall is otherwise cooled with atmosphere air such that the engine could deliver work as heat transfer occurs during rotation. A thermodynamic model of this engine was developed in this paper, and the effect of some parameters, including rotation speed, mass of air inside chamber, compression ratio and different heating temperatures, on the output power as well as thermal efficiency was investigated. It was found that the highest efficiency can reach 10.8% and the maximum output power can reach 0.3684W. The compression ratio of 4 was found to have the highest efficiency, and the compression ratio of 6 was found to have the maximum power output. Besides, it was found that as heating temperature increases the efficiency and power increase too

Abstract: The blended latex of natural rubber (NR) and styrene butadiene rubber (SBR) at dry weight ratio of 80/20 (NR/SBR) was reinforced with a very low loading level of either carbon nanotube (CNT) or nanosilica (nano-SiO2) (0.1-0.4 phr). The CNT and nano-SiO2 were compounded with NR/SBR rubber blend and other chemicals necessary for vulcanization in the latex state. The obtained nanocomposite latex was cast into thin sheet on a glass mold and then cured in an oven at 80°C for 3 h. The cured samples were subjected to the tensile, dynamic mechanical and thermal tests. The results revealed that the nanofillers have improved their tensile strength, modulus at 300% strain, dynamic mechanical properties and thermal stability but reduced the elongation at break. It was also observed that at similar nanofiller loadings the reinforcing effects of CNT are more noticeable than that of nano-SiO2.

Abstract: The vast majority of photosynthetic organisms utilize monovinyl chlorophyll for their photosynthetic reactions. For the biosynthesis of monovinyl chlorophyll, the reduction of the 8-vinyl group which is located on the B-ring of the macrocycle is essential. 3,8-Divinyl protochlorophyllide a 8-vinyl reductase (DVR) catalyzes the reduction of 8-vinyl group on the tetrapyrrole to an ethyl group, which is necessary for monovinyl chlorophyll (Chl) synthesis. The former studies indicated the DVR could enhance photosynthesis. The full-length cDNA encoding DVR was obtained from oleaginous microalgae Dunaliella parva, which include 1326 bp open reading frame (ORF), 22 bp 5′-untranslated sequence and 383 bp 3′-untranslated sequence. Dunaliella parva DVR showed the highest sequence similarity with the DVR from Chlamydomonas reinhardtii and Volvox carteri. The Dunaliella parva DVR also showed wide similarity with other species.

Abstract: To investigate the mixing uniformity between tracer gas and gas stream in the duct, numerical simulations of the CO tracer gas and air mixing in a 300mm diameter and 90 degree elbow duct were performed on the commercial CFD software FLUENT, and the comparisons between the simulation results and experimental data were analyzed. Tracer gas is injected by 5-point discharge, the mixing uniformity between tracer gas and air is better than that of 1-point discharge. The results indicated that the tracer gas concentrations of simulations were agreed with the experimental data. Simulation results could provide a valuable guidance for gas flow rate measurement and online calibration for gas flowmeter with tracer gas technique.

Abstract: A new sliding mode variable structure controller is proposed. First, aiming at improving the convergence speed, a new nonlinear sliding mode surface is proposed. Then, the initial error speed is designed to make the initial state of the system to be just on the sliding mode surface which is to impair the chattering and improve the robustness of the controller. Finally, a mobile manipulator with two arms is taken as an example to simulate the trajectory tracking with the proposed controller. It is found that system shows high convergence speed and strong robustness against disturbance. The chattering is also impaired greatly.

Abstract: The traditional opinions regard energy as the main factor for the economic development, but not the key one, because there are different conclusions from the practical researches on the relationship between the energy consumption and economic development. The article utilizes the Granger casual test and Cointegration test to analyze the dynamic relationship between energy consumption and economic development in China. Based on our conclusion that economic development relies on energy consumption, some suggestions are given for energy saving and development in the long-term.

Abstract: In-situ combustion (fire flooding) is one of important methods to improve heavy oil recovery ratio, utilizing the reservoir itself heavy component burning as dynamic displacement of crude oil, improving the crude oil character, flooding efficiency is high, applicability is extensive, and other recover techniques can not match. But the technical support is difficult and broad, and is the key in restricting the effect of in-situ combustion, especially for the effectiveness of development. With the increase of fire flooding development, flowing wells turns to artificial lifting wells, the gas production increases deeply, and the lifting technology faces a lot of new problems. Aiming at the problems of combustion in-situ, the relevant technologies were researched, then some methods and measures suiting to heavy oil fire flooding technology were proposed. And it provided reference for researching of deep heavy oil fire flooding lifting technology in the future.

Abstract: Variable structure control (VSC) has the ability of overcoming chattering and external disturbance. In this paper the temperature control based of Variable Structure Control is presented for the molten carbonate fuel cell (MCFC) which is a promising device for stationary power and heat supply. The parameters of VSC are obtained by Particle Swarm Optimization (PSO). Numerical results demonstrate the effectiveness and advantages of this approach. The simulation and the results showed that the VSC and the PSO receding optimization applied to the MCFC temperature control yielded good performance.

Abstract: The most commonly used Micro tubular solid oxide fuel cell (MT-SOFC) anode material is a two phase nickel and yttria stabilized zirconia (Ni/YSZ) cermet. And the mechanical stability of anode support layer, in anode-supported electrolyte designs, is very important for large scale applications. During the assembly of stack and normal operation, MT-SOFC is easy to crack under the residual stress induced by manufacture and thermal stress due to multi-physics coupling. In this work, MT-SOFC model was founded on the background of MT-SOFC stack of electric vehicle and was analyzed by finite element method, based on theories of multi-physical field coupling. In order to find out which is the main reason for cracking, the residual stress due to manufacture and work were investigated separately. Thermal stress based on residual stresses of operating are studied for further research of life of MT-SOFC. It concluded that the failure of the MT-SOFC occurs mainly because of the residual stress due to the mismatch between the coefficients of thermal expansion of the materials of the electrode assembly, thermal stress will increase the mismatch in some partial areas. The results are important for studying the life and final spallation of MT-SOFC of electric vehicle.