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51.
The mechanism of the suppression of vapor explosions by adding inversely soluble polymers in water is studied. Vapor explosion experiments and quench experiment are conducted using a silver test piece. Polymetric solution (polyethylene oxide), of concentrations from 0 to 500 wppm, whose normalized viscosity (by water) varies from 1.00 to 2.00, is used. No vapor explosion is observed in the aqueous polymer solution at a concentration higher than 200 wppm. Quench experiments using the silver test piece submerged in the polymer solution and water are performed in order to examine the stability of film boiling. The suppression of the vapor film collapse is attributed to the precipitation of polyethylene as a gel around the vapor film. © 2002 Wiley Periodicals, Inc. Heat Trans Asian Res, 31(4): 297–306, 2002; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/htj.10037 相似文献
52.
A bright electroless Ni-P deposition on AM50 magnesium alloy in a sulfate plating bath was proposed by using direct plating process with non-chromate pretreatment. The electroless Ni-P plating on AM50 magnesium alloy has an admirable appearance and good adhesion. The results indicate that the electroless Ni-P deposition with non-chromate pretreatment has better adhesion than that of zinc immersion coating. Anodic polarization curves indicate that the electroless Ni-P deposition obtained from the sulfate bath has similar corrosion-resistance to that obtained from basic nickel carbonate bath. The deposition process generates less pollutant by a non-chromate plating bath and is suitable for the magnesium alloys manufacture because of its low cost. The hardness of the electroless Ni-P plated AM50 is about HV 720.6 and HV 969.7 after heat treatments at 180℃ for 2 h. The wear resistance of Ni-P plated magnesium alloy specimens is about 5 to 9 times as high as that of bare magnesium alloys. 相似文献
53.
54.
等离子喷涂燃料电池连接板LSM薄膜的性能研究 总被引:2,自引:2,他引:0
采用等离子喷涂法在SUS 430连接板基体上制备了LSM(La0.8 Sr0.2 MnO3)薄膜。用X射线衍射仪、扫描电镜和电子探针分别研究了喷涂前后LSM的相组成、薄膜的表面形貌和元素分布。用图像分析法计算了薄膜的孔隙率。二支点法测量了有与无LSM薄膜的SUS 430基体在130~800℃时的电导率。结果发现,薄膜与基体结合良好,薄膜孔隙细小,均匀分布,且非连通;LSM的相组成在喷涂前后保持一致;当温度<330℃时,有LSM保护膜的连接板的电导率小于无LSM薄膜的连接板的电导率;温度>330℃,结果相反。有LSM保护膜的连接板在空气中,130~800℃下,最大电导率为0.60Ω-1·cm-1。 相似文献
55.
PHILIP M KELLY 《International Journal of Dairy Technology》2006,59(2):70-75
Global trade in preserved milks is on the increase as new markets open up in regions of the world that have not been traditionally associated with milk consumption. Equally, a rise in world milk production is forecasted to continue, and the indications are that significant quantities of the extra milk produced will be converted to commodity products such as butter and powders. Consequently, on-going investment in new spray drying capability is likely to track geographical shifts in milk production. Successful application of advanced process control to the operation of large scale drying plant is both a priority and a challenge.
Meanwhile, opportunities for the exploitation of milk as a source of functional ingredients are being availed of by the dairy industry as it continues to achieve added value and unique key selling points. Recent research on the role of spray drying, along with other processes in the development of dairy ingredients for applications in chocolate and the preparation of microencapsulated powders, is reviewed. 相似文献
Meanwhile, opportunities for the exploitation of milk as a source of functional ingredients are being availed of by the dairy industry as it continues to achieve added value and unique key selling points. Recent research on the role of spray drying, along with other processes in the development of dairy ingredients for applications in chocolate and the preparation of microencapsulated powders, is reviewed. 相似文献
56.
57.
The effect of reducing the reactor air pressure on the morphology of spray dried magnesium sulphate powders is investigated, experimentally. A reactor, capable of drying and pyrolyzing solution sprays at low pressures, is designed and manufactured. A vibrating mesh nebulizer is employed to generate the spray. Four different pressures, starting from 60 Torr to the atmospheric pressure, and two different reactor air temperatures of 130°C and 420°C, are considered. In addition, two different concentrations of magnesium sulphate solutions are tested. The results are explained based on the effect of reactor air pressure on the droplet evaporation rate. 相似文献
58.
Alumina coatings have been deposited by combustion flame pyrolysis on amorphous silica and stainless steel substrates with the objective to study the effect of solvent composition, Fe3+ addition and determine the thermal fatigue lifetime. The effect of solvent composition on crystallinity, transformation temperature and hardness are studied, three different solvent compositions are chosen for preparing the aluminium nitrate solution. Using 100% water, as-deposited films are amorphous and transform to α-alumina only upon annealing, while this equilibrium phase is directly obtained but with a porous microstructure by using 100% methanol. The hardness of the coatings varies with the flammability of the solvents. The effect of Fe3+ addition on the crystallization of alumina is studied by combustion pyrolysis of aqueous solutions of Al3+ and Fe3+ nitrates. Small amount of ferric nitrate reduced the transformation temperature by 100 °C. Thermal cycling of as-deposited amorphous alumina on stainless steel substrate is carried out at different temperatures to determine the thermal fatigue lifetime. 相似文献
60.
Semiconducting molybdenum trioxide thin films have been prepared by employing simple and inexpensive spray pyrolysis technique.
Films are found to be polycrystalline in nature with hexagonal phase. Optical band gap energy (direct) and room temperature
electrical resistivity are of the order of 2·9 eV and 108 ohm-cm, respectively. These films exhibit cathodic electrochromism. 相似文献