膨胀型钢结构防火涂料分段等效热阻的确定

在总结分析膨胀型防火涂料隔热性能评价方法的基础上,提出了分段等效热阻的概念,即用热阻值的大小综合反应涂料的导热系数和膨胀厚度的变化,根据膨胀型防火涂料的反应特点,将涂料的热阻分为膨胀前和膨胀后两个阶段分别进行计算,并提出了计算分段等效热阻的方法。对2种型号的膨胀型防火涂料进行了标准条件实验,用分段等效热阻模拟的试件温升与实验结果相一致。分段等效热阻可以作为不同型号防火涂料隔热性能的评价依据,为更准确地进行钢构件的防火设计提供数据参考,并可以辅助分析防火涂料的防火机理。     

Synthesis and characterization of the carbon nanotube-based composite materials with poly(3,4-ethylenedioxythiophene)

We report a procedure to prepare a conducting nano-composites composed of multi-walled carbon nanotubes (MWNTs) and PEDOT by using a poly(sodium 4-styrenesulfonate) (PSSNa) as a inter-linking molecule between MWNT and PEDOT. When PSSNa chains are introduced on the MWNTs via physicochemical interaction, the surface of MWNT becomes negatively charged, and PSS-modified MWNTs promote the effective association of the positively charged PEDOT chains. The resulting MWNT-PSS/PEDOT composites are characterized by a better interconnection between MWNT and PEDOT components.     

The effect of LED irradiation on the quality of cabbage stored at a low temperature

The effects of light emitting diode (LED) irradiation on maintaining freshness and nutrition in cabbage during low temperature storage were investigated. Cabbage, ‘Dongdori’ was stored at 4–5°C for 18 days under white, green, blue, and red LED light. On day 15 of storage, the total chlorophyll content of cabbage was highest for green, followed by white, red, blue, and a nonirradiated control group. The vitamin C content was highest for blue, followed by white, green, red, and the control. On day 18 of storage, the total polyphenolic content in cabbage was highest for blue followed by white, red, green, and the control. LED irradiation is effective for enriching the chlorophyll, vitamin C, and polyphenol contents of cabbage stored at a low temperature and results suggest that LED colors have different effects.     

A hybrid interval-parameter fuzzy robust programming method and its application to filter management strategy in fluid power systems

An interval-parameter fuzzy robust programming (IFRP) method is developed for the assessment of filter allocation and replacement strategies in a fluid power system (FPS) under uncertainty. The developed IFRP can effectively handle the uncertainties expressed as fuzzy sets, interval values, and their combinations, which exist in contaminant ingression/generation of the system and contaminant-holding capacity of filter without making assumptions on their probabilistic distributions. The fuzzy decision space can be delimited into a more robust one with the uncertainties being specified through dimensional enlargement of the original fuzzy constraints, leading to enhanced robustness for the optimization process. Results indicate that the developed IFRP can not only help decision-maker to identify optimal filter allocation and replacement strategies to control the contamination level of FPS with a minimized system-cost and system-failure risk under multiple uncertainties, but also mitigate uncertainties through abating interval widths of the replacement periods and service life under different contamination ingression/generation rates.     

Self‐assembled structures in polystyrene‐block‐polyisoprene‐blend‐polystyrene and polystyrene‐block‐poly(methyl methacrylate)‐blend‐polystyrene or ‐blend‐poly(methyl methacrylate) in the strong segregation regime

This study deals with the investigation of microphase‐separated morphology and phase behaviour in blends of polystyrene‐block‐polyisoprene with homopolystyrene and blends of polystyrene‐block‐poly(methyl methacrylate) with homopoly(methyl methacrylate) or homopolystyrene in the strong segregation regime using small‐angle X‐ray scattering and transmission electron microscopy as a function of composition, molecular weight of homopolymers, r_M and temperature. Parameter r_M = M_H/M_C (where M_H is the molecular weight of homopolymer and M_C that of the corresponding block copolymer) was selected to encompass behaviour of the chains denoted as a ‘wet brush’ (i.e. r_M < 1). The relative domain spacing D/D_o increases in the regime 0 < r_M?1 with increasing concentration of homopolymer w_P and increasing r_M but depends on the specific implemented morphology. We tested a new approximate D/D_o versus w_P relation in the strong segregation regime using block copolymers of high molecular weights. It is shown that the parameters r_M and χ^3/2N determine the slope of the D/D_o versus w_P relation in the strong segregation regime and the new approximation generally matches the experimental data better than the approximations used so far. Copyright © 2010 Society of Chemical Industry     

Analysis of Methanol Production from Biomass Gasification

A biomass‐based methanol production process was investigated. The process consists of a biomass gasifier, steam reformer, and methanol synthesis reactor as the main units. Reactors were simulated by applying the kinetic models previously developed and the process was analyzed based on the simulation results. The key parameters, the equivalence ratio in biomass gasification, the temperature in steam reforming, and the recycle of hydrogen in methanol synthesis were identified. These parameters affect the methanol production. The process analysis indicates that the optimal combinations of the parameters can greatly enhance the methanol production and the thermodynamic efficiency. Finally, the elemental analysis for carbon and hydrogen along the process was carried out.     

Calculation of alcohol‐acetone‐cellulose acetate ternary phase diagram and their relevance to membrane formation

ABSTRACT Alcohol‐acetone‐cellulose acetate phase diagrams incorporated with methanol, ethanol, and isopropanol as nonsolvents are calculated according to a new form of the Flory–Huggins equation. Nonsolvent–cellulose acetate interaction parameters are measured by swelling experiments. Concentration‐dependent nonsolvent–solvent interaction parameters are obtained by vapor–liquid equilibrium and the Wilson equation. It is shown that alcohol is a week coagulant compared with water, and water > methanol > ethanol > isopropanol for cellulose acetate. The phase diagrams characteristic of acetone‐cellulose acetate combined with water, methanol, ethanol, and isopropanol as nonsolvents is different, which leads to the different morphological structure of a cellulose acetate membrane. The structure of a water coagulated membrane has large macrovoids from liquid–liquid phase separation. A methanol coagulated membrane has a honeycomb‐like structure from spinodal microphase separation. An ethanol or isopropanol coagulated membrane has a thicker, dense top layer from the delay time phase separation. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1650–1657, 2001     

Influence of isomer ratio and ring substituents in decomposition activation energies of α,α,α′,α′‐tetrasubstituted dibenzyls

Diethyl‐2,3‐dicyano‐2,3‐di‐(X‐substituted phenyl) succinates (X = p‐OCH₃, p‐CH₃, p‐Cl, H, p‐NO₂) can initiate the free‐radical polymerization of styrene. The decomposition rate constant and activation energy were measured by means of a dilatometer, and the results showed that they were strongly dependent on the ratio of meso‐ and dl‐isomers in the polysubstituted dibenzyl compounds and the properties of the ring substituents. On the other hand, it was found that the polystyrenes, which were obtained by initiation with hydrogen, had a much larger average molecular weight than that with p‐OCH₃ and p‐CH₃. The experimental phenomena were correlated with the structure of the radical resulting from hydrogen. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 2964–2971, 2001     

同层排水系统的应用浅析

对比分析了同层排水与传统排水分式存在的优点和缺点,以及目前常见的同层排水施工中存在的应注意问题,介绍了宁波地区两个应用同层排水系统的实例及其效果。     

Effect of heat treatments and homogenisation pressure on the acid gelation properties of recombined whole milk

The homogenisation pressure and the order of heating and homogenisation were varied in the preparation of recombined whole milks. The fat globule sizes decreased from ∼2 to 0.2 μm as the homogenisation pressure increased from 50 to 850 bar for samples heated before (HEHO) or after (HOHE) homogenisation. For acid gels prepared from the milks, small increases in elastic modulus of the set gels were observed with decreasing fat globule size. The yield strain of the acid gels increased linearly with decreasing fat globule size, and HOHE gels had higher yield strains than HEHO gels. The yield stress of the set gels increased with decreasing fat globule size, and the yield stress for HOHE gels were higher than the HEHO gels. Confocal micrographs of the gels revealed an almost continuous protein network structure without pores for gels from milks treated at low homogenisation pressures, and the large fat globules did not actively interact with the strands in the gel network. In contrast, a porous protein network structure with distinct strands was observed for the samples treated at high homogenisation pressures, and the small fat globules were intimately involved in the strands in the network structure. The HOHE gels had a more porous protein network with thicker strands than the HEHO gels. The size of the fat globules and their incorporation in the protein network during acidification is proposed to affect the acid gel structure and properties.