琼脂、丙烯酸钠-丙烯酰胺高吸水性复合材料的合成及性能研究

采用水溶液聚合法制备了琼脂、丙烯酸钠-丙烯酰胺高吸水性复合材料。考察了琼脂用量、交联剂、引发剂和单体质量比等因素对复合材料吸液倍率的影响,并对琼脂用量及丙烯酰胺用量对吸液倍率的影响进行线性回归分析,对材料的反复吸液性能和在不同盐中的吸液性能进行了测试研究。结果表明:在优化条件下制备的复合材料的吸水倍率和吸0.9%NaCl溶液分别可达到1150g/g与88g/g,一定范围内,丙烯酰胺占单体总质量的质量分数对吸液倍率的影响作用更大,且材料具有良好的反复吸液性和耐盐性。     

无N2下合成钠基膨润土/P(AA-AM)复合吸水树脂的研制

以N,N'-亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,丙烯酸(AA)和丙烯酰胺(AM)为单体,采用水溶液聚合法合成出钠基膨润土复合聚丙烯酸钠-丙烯酰胺复合吸水树脂.研究了钠基膨润土的添加量、交联剂用量、引发剂用量、中和度及AM的用量对吸水倍率的影响.结果表明,钠基膨润土用量为40%,交联剂用量为0.025%,引发剂用量为0.3%,AM用量为12%及AA的中和度为80%时,吸蒸馏水倍率与吸收0.7%NaCl溶液倍率分别为422.28 g/g和65.80 g/g.     

淀粉/膨润土复合高吸水树脂的制备工艺研究

以淀粉、膨润土、丙烯酸、丙烯酰胺等为原料,采用微波辐射法制备复合高吸水树脂。研究了膨润土用量、丙烯酰胺用量、引发剂用量、交联剂用量等对高吸水树脂吸液率性能的影响。实验结果表明,不同比例下的原材料制得的树脂吸水倍率差异很大。在交联剂为0.045%,引发剂0.32%,中和度70%,膨润土10%,磷酸酯淀粉3%,丙烯酸与丙烯酰胺质量比为2∶1,微波功率为800W辐射15min时吸蒸馏水倍率为796g/g,当丙烯酸与丙烯酰胺质量比为1∶1时,吸0.9%NaCl溶液倍率达95g/g。     

坡缕石/聚丙烯酸钠高吸水保水复合材料的制备与性能研究

采用水溶液聚合法,以丙烯酸为单体,过硫酸钾为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,制备出了坡缕石/聚丙烯酸(钠)高吸水保水复合材料,并采用筛网法测试了产品的吸液性能.通过单因素实验,系统地研究了矿物含量、交联剂用量、引发剂用量、单体中和度等聚合条件对复合材料吸蒸馏水倍率和0.9%NaCl溶液倍率的影响.制备出的坡缕石/聚丙烯酸(钠)复合材料具有较高的吸液倍率及良好的耐盐性.     

聚(丙烯酸盐共聚丙烯酰胺)/膨胀蛭石高吸水性复合材料的制备

以N,N'-亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,丙烯酸和丙烯酰胺为单体,采用新型溶液聚合法制备了聚(丙烯酸盐共聚丙烯酰胺)/膨胀蛭石高吸水性复合材料.考察了交联剂用量、引发剂用量、单体浓度、中和度、反应温度、膨胀蛭石含量及单体质量比对吸水倍率的影响,试验结果表明:当膨胀蛭石含量为20 wt%时,交联剂用量为0.04 wt%,引发剂为1.3 wt%,中和度为80%,单体浓度为50 wt%,反应温度为80℃,吸水倍率与吸收0.9wt%的NaCl溶液倍率分别为1262 g/g和92 g/g.探讨了添加矿物提高其耐盐性的机理.     

膨胀蛭石/聚(丙烯酸钾-丙烯酰胺)高吸水性复合材料的制备、性能及表征

以N,N'-亚甲基双丙烯酰胺为交联剂,过硫酸钾为引发剂,丙烯酸和丙烯酰胺为单体,采用新型水溶液聚合法合成了膨胀蛭石/聚(丙烯酸钾-丙烯酰胺)高吸水性复合材料.考察了交联剂用量、引发剂用量、单体浓度、中和度、反应温度、单体质量比及膨胀蛭石含量对吸水倍率的影响,试验结果表明,当蛭石含量为30%(相对单体质量,下同)时,交联剂用量为0.04%,引发剂为1.1%,中和度为75%(相对丙烯酸物质的量),单体浓度为50%,反应温度为75℃,吸水倍率最高可达1048g/g.最后,采用SEM、IR对其结构及组成进行了表征.     

耐盐性魔芋葡甘聚糖吸水树脂的制备

以魔芋葡甘聚糖(KGM)为原料接枝丙烯酰胺、丙烯酸制备耐盐性吸水树脂,研究了接枝共聚反应单体及KGM质量配比、中和度、交联剂浓度、引发剂浓度、乙二胺四乙酸(EDTA)质量分数对吸水树脂吸液倍率的影响,通过Box-Behnken实验设计对制备条件进行优化。结果表明,丙烯酰胺与丙烯酸质量比为0.192,交联剂浓度为0.067g/mol,引发剂浓度为0.439g/mol,中和度为90%,乙二胺四乙酸(EDTA)质量分数为12.2%时,该耐盐性树脂吸生理盐水倍率达125g/g,吸纯水倍率达700g/g。     

高岭土复合聚(丙烯酸-co-丙烯酰胺)高吸水树脂的制备及性能研究

采用水溶液聚合法制备高岭土复合聚(丙烯酸-co-丙烯酰胺)高吸水树脂,用红外光谱对树脂的结构进行表征。在将聚合反应与树脂的干燥同时进行的基础上探讨了交联剂用量、引发剂用量、单体配比、丙烯酸中和度、高岭土添加量等条件对树脂吸液性能的影响。结果表明:当丙烯酸中和度75%、单体配比3.5:1、高岭土添加量15%、交联剂用量0.02%、引发剂用量0.8%时,树脂的吸液性能整体最好,吸水倍率达698g·g-1、吸盐水倍率110g·g-1。红外光谱结果表明,丙烯酸、丙烯酰胺单体与高岭土的-OH发生了接枝共聚反应。     

膨润土复合甲基丙烯酸高强度吸水剂的制备及性能表征

以膨润土和甲基丙烯酸为原料,N′N-亚甲基双丙烯酰胺为交联剂,过硫酸铵为引发剂,采用溶液聚合法制备了膨润土复合甲基丙烯酸聚合物高强度吸水剂,通过红外光谱对其结构进行了表征。研究了吸水剂中膨润土加入量、单体中和度、交联剂用量等对吸水性和强度的影响,并测试了吸水剂的吸水性能和压缩强度。结果表明,当膨润土用量为10%,氢氧化钠浓度为2mol/L,单体中和度为80%,交联剂用量为0.75%时,制备的吸水剂在室温下对蒸馏水吸水倍率达382g/g,对自来水吸水倍率可达216g/g;地0.9%的Na2SO4溶液中吸水倍率为76g/g,压缩强度为16.73MPa,说明制备的吸水剂具有较好的强度和吸水性能。     

机械活化淀粉接枝丙烯酸高吸水树脂的制备与性能研究

以机械活化木薯淀粉、丙烯酸为主要原料,过硫酸铵为引发剂,采用反相乳液聚合法制备了机械活化淀粉接枝丙烯酸高吸水树脂,考察了引发剂用量、交联剂用量、丙烯酸(AA)中和度和单体淀粉质量比等因素对吸液性能的影响。结果表明:制备机械活化淀粉接枝丙烯酸高吸水树脂的最适宜工艺条件为引发剂用量为0.6%,交联剂用量为0.12%,丙烯酸中和度为80%,单体淀粉质量比为10∶1。在此条件下,树脂吸去离子水倍率为930.67g/g,吸生理盐水倍率为90.57g/g。对产物进行红外分析的结果表明活化木薯淀粉与丙烯酸发生了接枝共聚反应。     

Insertion of triangulated surfaces into a meccano tetrahedral discretization by means of mesh refinement and optimization procedures

In this paper, we present a new method for inserting several triangulated surfaces into an existing tetrahedral mesh generated by the meccano method. The result is a conformal mesh where each inserted surface is approximated by a set of faces of the final tetrahedral mesh. First, the tetrahedral mesh is refined around the inserted surfaces to capture their geometric features. Second, each immersed surface is approximated by a set of faces from the tetrahedral mesh. Third, following a novel approach, the nodes of the approximated surfaces are mapped to the corresponding immersed surface. Fourth, we untangle and smooth the mesh by optimizing a regularized shape distortion measure for tetrahedral elements in which we move all the nodes of the mesh, restricting the movement of the edge and surface nodes along the corresponding entity they belong to. The refining process allows approximating the immersed surface for any initial meccano tetrahedral mesh. Moreover, the proposed projection method avoids computational expensive geometric projections. Finally, the applied simultaneous untangling and smoothing process delivers a high‐quality mesh and ensures that the immersed surfaces are interpolated. Several examples are presented to assess the properties of the proposed method.     

From Industry 4.0 to Research 4.0. Development of High Performance Fibers in the Light of Digitization

We associate a variety of innovations with the term ＂Industry 4.0＂. The pioneer of many 4.0 modifications forms the basisfor the trend towards the integrated di...     

Roman iron and steel: A review

ABSTRACT

The production of ferrous metal increased during the Roman Late Republican period, Principate and Empire. The direct bloomery process was used to extract the metal from its ores using slag-tapping and slag-pit furnaces. The fuel was charcoal and an air blast was introduced by bellows-operated tuyères. Iron formed as a bloom, often as a spongy mass of metal, which contained impurities from the smelting process, including unreacted ore, fuel, slag and fragments from the furnace walls, while the metal was often inhomogeneous with varied carbon contents. Blooms were either smithed directly into bars or ingots or they were broken up, which also allowed the removal of gross impurities and a selection of pieces with similar properties to be made. These could then be forge-welded together and formed into characteristically shaped ingots. Making steel in the furnace seems to have been achieved: it depended on the ore and the furnace and conditions within it. Surface carburization was also carried out. Iron and steel were used extensively in construction and for tools and weapons. Fire welding was often used to add pieces of steel to make the edges of tools and weapons, which could be heat-treated by quenching to harden them.     

The Research of Anti-Wear Properties of Organomolybdenum Compounds in the Engine Oils

A four-ball tester was used to evaluate the anti-wear performance of three kinds of organomolybdemun compounds in the engine oils, i. e., molybdenum dialkyldithiophosphate (MoDDP), molybdenum dialkyldithiocarbamate ( MoDTC), and sulphur and phosphorus freeorganomolybdeum (Molybdate). The results indicate that a low concentration of MoDDP doesn' t improve the anti-wear properties of the commercial engine oils, but a high concentration of MoDDP can obviously improve the anti-wear properties and the load-carrying capacity of the engine oils. MoDTC doesn' t improve the antiwear properties of the engine oils, but worsens the anti-wear properties of the oils. Signifi can timprove ment of frictional and wear characteristics is obtained with Molybdate added in the commercial engine oils and the formulated oils.     

Certification Institutions Expected to Update and Transfer Information on Present Standards

Standards are the basis for production enterprises to organize production, ex-factory inspection, trade (delivery) and technical exchanges, product certification, quality arbitration and supervision.……     

Flow calorimeter for enthalpy increment measurements on condensed gases

A flow calorimeter for enthalpy increment measurements on condensed gases is presented. A better knowledge of the properties of the liquefied natural gas is needed, and therefore a liquid loop has been designed for our flow calorimeter. The fluid loop in the calorimeter is designed in order to avoid the two-phase region, since two phases would give compositional disturbances in the measurements. The avoidance of the two-phase region is made possible by increasing the pressure of the test fluid after the measurement section, then heating the fluid at super-critical pressure past the critical point. Finally, the fluid is throttled to the low-pressure gas state at the inlet condition of the compressor that circulates the fluid. To perform the pressure increase, a new cryogenic pump has been designed. To evaluate the new equipment, measurements were taken on liquid ethane over the temperature range 146–256 K at pressure between 0.9 and 5.1 MPa.     

Synthesis of Alumina-Zirconia Nanocomposites by Solgel Process

Al₂O₃-ZrO₂ nanocomposites were developed starting with the solgel process. Composite alumina-zirconia nanopowders were synthesized from metallorganic precursors (Aluminium secondary butoxide and zirconium Iso propoxide) using the solgel process. The parameters affecting the synthesis—solvent, concentration of precursor, R/H ratio (i.e., dilution of water in solvent)—were varied as also the temperature and pH. BET and TEM were used to measure nanosize. Diffuse reflectance spectroscopy and also qualitative optical absorption led to identical particle size estimate. The variation of process parameters was used to study the effect and interdependence of process parameters. Artificial Neural Networks was used to rigorously analyze the process. Although this led to confirmation of interdependence of parameters, the presence of a single overwhelming solvent variable was also established. Then the optimal process was used to synthesize more nanopowder. To produce bulk nanocomposite the nanopowders were sintered by varying the temperature and time period. The sintered lithoids were probed with a vickers hardness tester to measure elastic modulus, hardness, and fracture toughness. The results showed high elastic modulus, modest hardness, and very high fracture toughness.     

Refrigerators Enter a New Era of Health Preservation Frestech initiates the establishment of China's first standard for household sterilization refrigerators

On November 30, 2007, the China Association for Standardization (CAS) held a press conference at Beijing Diaoyutai State Guest House. Leaders from the China Household Electric Appliance Research Institute, the China Household Electric Appliance Association, and the China Consumers' Association attended and made speeches.……     

Friction Stir Processing Strategies for Uniform Distribution of Reinforcement in a Surface Composite

Friction stir processing (FSP) is an important technique for preparing surface composites. Fabricating defect-free surface composites with uniform particle distribution by FSP is a challenging task. In this study, silicon carbide particles reinforced AA5083 alloy surface composites was fabricated using different FSP strategies including variation in process parameters, dual-tool processing and tool offset overlapping. Material flow of the processed material with reinforcement particles demonstrated that the distribution of particles was influenced by the stirring action of the probe as well as the extrusion of the plasticized material due to the movement of the tool. Process parameters, particularly rotational speed, showed a dominant influence on the distribution of silicon carbide particles.