CMS-g-PAA高吸水性复合材料的制备及性能研究

以废弃全棉面膜基布(CMS)和丙烯酸(AA)为原料,采用自由基溶液聚合法制备CMS-g-PAA复合高吸水性材料,并用红外光谱(FTIR)进行表征。研究了吸水性、保水性及反复吸放液性能,采用准一级、二级动力学模型对其吸水溶胀过程进行模拟研究。结果表明,全棉面膜基布和丙烯酸单体之间发生了接枝共聚反应,所合成的CMS-g-PAA复合材料在去离子水和0.9%(质量分数)NaCl溶液的吸水倍率分别可达211.3g/g和45.5g/g,且溶胀过程符合准二级动力学吸附模型。在较高温度和一定压力下,CMS-g-PAA均具有良好的保水性能。反复吸放液性能测试表明循环8次后,去离子水和0.9%(质量分数)NaCl溶液的吸水倍率分别保持了最大吸水倍率的64.9%和44.4%。     

聚（丙烯酸-CO-丙烯酰胺）／腐殖酸钠／高岭土复合高吸水性树脂的制备及溶胀行为

以N,N′-亚甲基双丙烯酰胺为交联剂、过硫酸铵为引发剂,采用水溶液聚合法合成了聚(丙烯酸-co-丙烯酰胺)/腐殖酸钠/高岭土多功能复合高吸水性树脂。研究了腐殖酸钠和高岭土含量对吸水倍率的影响,同时考察了该树脂的吸水速率及溶液pH值和不同阴阳离子对吸水倍率的影响。结果表明,在腐殖酸钠∶高岭土=2∶3(质量比)时树脂具有最高的吸水倍率,其吸蒸馏水和0.9%(质量分数)NaCl溶液分别达到450 g/g和39 g/g。     

水体系中制备改性聚天冬氨酸/聚丙烯酸复合吸水性树脂

以改性聚天冬氨酸(MKPAsp)为交联剂,丙烯酸(AA)为单体,过硫酸钾(KPS)为引发剂,通过水溶液聚合法制得可生物降解的聚天冬氨酸/聚丙烯酸(MKPAsp/PAA)复合吸水性树脂,探讨了组成、交联剂和引发剂用量对复合吸水性树脂吸水性能的影响。结果表明:当AA与改性聚琥珀酰亚胺(KPSI)的质量比为5∶1、乙烯基三乙氧基硅烷(A151)用量为0.42%(摩尔分数)、KPS用量为0.2%(质量分数)时,MKPAsp/PAA的吸液性能最好,在去离子水和0.9%NaCl盐溶液中吸液倍率分别为886.7和120.3g/g,比未复合的KPAsp树脂分别提高了3.8和1.1倍。采用红外光谱、扫描电镜和热重等手段对复合吸水性树脂进行了表征,结果表明:PAA的加入不仅能够改善吸水性树脂的孔道结构,使孔径更加规则均匀,而且能够提高吸水性树脂的热稳定性。     

椰糠粉/聚丙烯酸-丙烯酰胺复合吸水材料的制备及其吸保水性能

以椰糠粉为基体材料,丙烯酸和丙烯酰胺为单体,N,N-亚甲基双丙烯酰胺(MBA)为交联剂,过硫酸钠为引发剂,采用水溶液聚合法制备了椰糠粉/聚丙烯酸-丙烯酰胺复合吸水材料。较优的合成条件是:单体与椰壳粉质量比为8∶1,丙烯酸的中和度为70%,引发剂用量是单体质量的0.8%,交联剂N,N-亚甲基双丙烯酰胺用量是单体质量的0.2%,反应时间4h,温度50℃。对最佳条件下制备的吸水材料进行了FTIR和SEM表征及吸水性、保水性、重润胀性等测试,并且对该材料在去离子水和0.9%NaCl溶液中的吸水性进行对比。此外,用分子扩散方程及一级、二阶动力学模型对其吸水溶胀过程进行模拟研究。结果表明,该复合吸水材料在去离子水和盐溶液中的吸水倍率分别是273.54g/g和44.54g/g;吸水动力学表明水分扩散满足Fickian扩散,且一级动力学方程能描述润胀吸水过程;该材料重润胀3次后仍具有很好的吸水性。     

PAM/凹凸棒粘土复合高吸水性树脂的吸水性能

系统考察了金属离子的价态、种类以及溶液的pH值对聚丙烯酰胺/凹凸棒粘土复合高吸水性树脂吸水倍率的影响。结果表明,复合高吸水性树脂的吸水倍率随着金属离子盐溶液浓度的增大而减小,在不同价态金属离子盐溶液中,树脂的吸水倍率顺序为N a >M g2 >C a2 >F e3 。通过红外光谱探讨了金属离子与复合高吸水性树脂的作用方式;同时还考察了交联剂含量对其吸水倍率、吸水速率和反复吸水性能的影响。     

鱼蛋白接枝聚合丙烯酸高吸水树脂的制备

用溶液聚合法制备了鱼蛋白基丙烯酸(FP-g-AA)高吸水性树脂。采用单因素法改变组分配比分别进行合成试验。并通过对产品的吸(盐)水性能的测试,优化合成配方及用红外光谱仪对产物进行表征。结果表明,当过硫酸钾、N,N′-亚甲基双丙烯酰胺、鱼蛋白用量分别为丙烯酸的1.0%、0.07%、10.0%,丙烯酸的中和度和在溶液中的质量分数分别为80%和18%时,该高吸水性树脂的吸水倍率达981g/g,吸生理盐水(0.9%NaCl)倍率达127g/g。红外光谱也显示,产品为鱼蛋白接枝聚合丙烯酸树脂。     

微波辐射交联羧甲基纤维素接枝丙烯酰胺制备高吸水性树脂及溶胀性能

以交联羧甲基纤维素(CCMC)、丙烯酰胺(AM)为原料,过硫酸钾(KPS)为引发剂,N,N′-亚甲基双丙烯酰胺(NMBA)为交联剂,通过微波辐射法制备了高吸水性树脂AM-g-CCMC。探讨了NMBA、KPS和CCMC用量对树脂吸水倍率的影响;采用IR,TG-DTA和SEM对树脂进行了表征。结果表明,在最佳制备条件AM∶CCMC∶NMBA∶KPS=50∶5∶0.15∶2.5(wt,质量比),微波功率130W,反应时间200s下制备的树脂对去离子水和浓度为0.154mol/L的NaCl、CaCl_2和FeCl_3溶液的吸水倍率分别为1821、165、82和43g/g。     

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.     

响应面法优化HB/PAA复合高吸水性材料的制备

以废弃沙棘枝条(HB)和丙烯酸(AA)为原料,采用自由基溶液聚合法制备沙棘枝条/聚丙烯酸(HB/PAA)复合高吸水性材料。采用Box-Behnken响应面法,就引发剂、交联剂、中和度3个因素对吸水材料吸水性能的影响进行分析。结果显示,最佳的合成条件是:中和度为72.5%,引发剂和交联剂的用量分别为单体质量的1.3%(wt,质量分数,下同)、0.5%。在此条件下,HB/PAA的吸水倍率实际值为273.5g/g,与理论值相近。同时通过场发射扫描电镜表征所制备的高吸水性材料。     

淀粉/NaAA/CR吸水复合材料的性能在去离子水和盐溶液中的差异

采用机械共混法制备了淀粉/丙烯酸钠(NaAA)/氯丁橡胶(CR)吸水复合材料,考察了去离子水和3.5%(质量分数)NaCl溶液两种吸水介质对其力学性能和吸水性能的影响,并且观察了复合材料吸水前后的微观形貌。结果表明浸水后,随吸水量的增加,材料力学性能的降低;复合材料在盐溶液中的吸水率远小于在去离子水中的吸水率;在反复使用过程中,能够很好地保持其原有的吸水性能,具有优异的反复使用性能;通过扫描电子显微镜(SEM)观察了复合材料吸水前后的微观形态结构,吸水组分聚NaAA颗粒吸水干燥后表面发生褶皱。     

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.     

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.……     

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...     

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.     

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.……     

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.     

Optimum-Simulation von Ernteprozessen

Zusammenfassung Bei der Gestaltung von Ernteprozessen — beispielsweise des Prozesses Mähdrusch, Körnertransport und -abnahme — als transportverbundene Fließarbeitsverfahren mit mindestens zwei verschiedenen Arbeitsmitteln gibt es einen großen Optimierungsspielraum. Solche Prozesse sind mehrstufige Bedienungsprozesse mit gemischter Anordnung der Bedienungseinrichtungen. Außerdem besitzen sie stark ausgeprägte räumliche Aspekte. Es wird vor allem gezeigt, welche Merkmale solcher Prozesse in Simulationsmodellen abgebildet sein müssen, welche Zielgrößen in Abhängigkeit von welchen Einflußgrößen unter Berücksichtigung welcher Prozeßbedingungen ermittelt werden sollten und wie der Bewertungsprozeß zur Ermittlung der gewünschten Informationen gestaltet werden muß.     

A study of centrifugal cast high boron high speed steel

In the present study a high‐boron high speed steel (HSS) roll material was designed. Many expensive alloy elements have been substituted by cheap boron alloy, and high‐boron high speed steel roll has been manufactured by centrifugal casting method. The microstructures, mechanical properties and wear resistance of centrifugal casting high‐boron high speed steel roll have been investigated by optical microscopy (OM), scanning electron microscopy (SEM), and X‐ray diffraction (XRD) analysis, hardness test, impact test and wear test. The results indicated that the solidification microstructures of high‐boron high speed steel roll consisted of M₂(B,C), (W,Mo)₂(B,C), M₃(B,C), M₂₃(B,C)₆ type borocarbides and martensite, a small amount of retained austenite. Borocarbides were continuously distributed over the grain boundary. After quenching from 1050 °C, local broken network appeared in partial borocarbides, and fine secondary borocarbide precipitated from the matrix. After tempering from 525 °C, the amount of precipitated borocarbide increased significantly. After heat treatment, the hardness of high‐boron high speed steel roll excelled 60 HRC, and its impact toughness excelled 8.0 J/cm². The single groove steel rolling amount of high‐boron high speed steel rolls increases by 500% than that of bainite cast iron roll, when the rolls are used in K₁ mill housing of bar mill.     

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.