Advanced Materials Research Vols. 472-475

Abstract: Flow boiling heat transfer performances of refrigerant R410A in the horizontal micro-fin tubes with different geometric parameters were investigated. The dependencies of forced flow boiling heat transfer coefficient of R410A on mass flow rate, heat flux and were studied and the mechanism of flow boiling heat transfer under different working conditions were discussed. For a comparison, the influences of fin number and fin height of micro-fin tubes on heat transfer were also studied. The differences of heat transfer coefficient between R22 and R410A were analyzed. It is found that the heat transfer coefficients were nearly same for R22 and R410A and, in fact, the heat transfer coefficient of R22 was just a little higher than that of R410A by 4-7%.

Abstract: This article inherits a paper themed as Cationic modification process's depth exploration of cotton fibers. In this paper, we will primarily discuss cotton fibers’ strength, fineness and other aspects of performance compared between before and after modification, as well as their usability.

Abstract: It is difficult to cool high thermal flux electronics by traditional methods such as air cooling, common liquid cooling and so on. However, vapor compressor refrigeration system is an efficient approach to solve this problem. Heat sink is important equipment in system, so the goal of this paper is to design a heat sink which is similar to an evaporator in vapor compression system with head load 100W. Mathematical model of heat sink is set up. Different heat flux, pressure drop, heat transfer area and weight with different micro-channel width are obtained finally.

Abstract: The utilisation of phase change material (PCM) for thermal energy storage (TES) can significantly enhance the energy savings achievable with renewable thermal systems. Sphere based packed bed systems have been used as TES for many years. However, due to the thermal resistance within these systems, the heat transfer is limited and not all the PCM can be used effectively. This study focuses on heat transfer enhancement options for single PCM sphere in a TES system. An experimental investigation has been conducted using water as the PCM. The thermal performance of plain plastic sphere containing PCM has been compared to plastic sphere encapsulated with conducting pins. The heat transfer rate of the sphere with conducting pins was more than 34% that of the sphere without pins.

Abstract: Ocean atmospheric transmittance is an important factor to influence detecting distance of infrared system. The influence efficiency of infrared detection is studied by using modtran, on the basis of studying the character of infrared transmission. Firstly, major absorption band of vapor, carbon dioxide, ozone and vapor continuum and the change of transmittance in boundary layer, troposphere and stratosphere are analyzed. Secondly, atmospheric window transmittance of navy maritime aerosol in horizontal path and slant path is analyzed, and the influence of four types of maritime aerosol is also analyzed for navy maritime aerosol. Lastly, the influence of five model atmospheres to total transmittance is analyzed.

Abstract: This paper reviews the monitoring diagnostic methods for the sliding main engine bearing wear. Those methods by oil, temperature, vibration, strain and other surveillance means are in more engineering applications. Moreover, this paper expounds a kind of new diagnostic method for main bearing wear monitoring - the thermoelectric power monitoring method.

Abstract: This research was aimed at studying the effects of heating the paddy for insect killing and thereby improving subsequently milled rice quality. The experimental temperatures were in the range of 120-200°C, the paddy feeding rates were 60, 120, and 180 kg/h and the heights of the vibration screen were 5, 6, and 8 mm. The findings indicated that when the feeding rates increased between 120 and 180 kg/h, the insect death rate increased for nearly all temperature levels, whereas the feeding rate of 60 kg/h and the vibration screen height of 6 mm were found to give 100% insect killing efficiency. The resulting head rice yield increased by 0.3-0.7% for a screen height of 8 mm. The quantity of broken rice decreased whereas the total rice quantity did not vary significantly; the milled rice had a whiteness index slightly increased when compared to the reference rice.

Abstract: Abstract:Seepage is an important issue in geotechnical engineering projects such as dams, levees, canals, reservoirs, etcetera, and has made researchers and specialists to pay special attention to this problem. Lots of destructions in buildings, towers, dams, tunnels, slopes, and etcetera have been reported in history which, have been caused by liquefaction, ground water movement or other related seepage problems. In this article, seepage in soil-water systems and their related problems are studied using Element Free Galerkin Method (EFGM). For time dependent problems, implied finite difference method is used. A program is also written for both stable and time dependent cases. With estimation of a function and comparing the results with the exact function, the quantity of the errors is calculated and the accuracy of the method is evaluated. Based on this method, various geotechnical engineering problems are solved and analyzed. The results showed that not only is the EFGM more exact and accurate in comparison with other conventional methods but the time and costs for network production is omitted. With variations in boundaries, the application of EFGM is easier than that of Finite Element Method (FEM). Also, the ability of solving seepage problems without any limitation is a preference of EFGM in comparison with other approximate methods.

Abstract: Microstructure and electrochemical characteristics of La0.35Ce0.65Ni3.8-xCo0.8MnxAl0.4 alloys have been investigated. X-ray diffraction results indicate that the alloys consist of a single phase with CaCu5-type structure, and the lattice parameters a, c and cell volume V increase with increasing x value. The maximum discharge capacity of the alloy electrodes first increases from 217.9 (x = 0) to 290.1 mAh/g (x = 0.3), and then decreases to 271.3 mAh/g (x = 0.5). The high-rate dischargeability at the discharge current density of 1200 mA/g first increases from 58.4% (x = 0) to 78.2% (x = 0.3), and then decreases to 75.2% (x = 0.5). Both the charge-transfer reaction at the electrode/electrolyte interface and the hydrogen diffusion in the bulky alloys are responsible for the high-rate dischargeability. Cycling stability first increases with increasing x from 0 to 0.3 and then decreases when x increases to 0.5.

Abstract: Periodic economic fluctuation has become a common phenomenon in contemporary society, which is inevitable in both state-controlled economy countries and market economy countries. Since more and more countries realize the importance of keeping fingers on the pulse of the trend of macroeconomic situation, a variety of macroeconomic evaluation methods and indexes ,such as CPI，PPI and GDP are developed to describe and predict the regulate operation of the macro-economy. Nevertheless, those indexes have such many criteria due to different emphases that they even form an enormous and yet complex system. Consequently, efficient and effective research methods still remain unsettled. This conceptual paper puts forward a new research method---cluster composite index evaluation method, which can directly and accurately reflect the operation of macro-economy. Two case analyses of applying this method in macro-economy corroborate the method to be scientific and accurate.