废弃ACQ防腐杉木的苯酚液化工艺及残渣表征的研究

通过分析废弃ACQ防腐杉木在苯酚中的液化情况,通过正交试验方法研究了单因素变量对液化反应效率的影响,得出ACQ防腐木苯酚液化试验优化条件为:液化温度150℃,液化时间2.5h,液比为3.5,硫酸加入量为9％,得到残渣率为3％.4个因素的影响主次关系为:硫酸加入量＞液比＞液比时间＞液化温度.并对液化残渣结构进行了表征分析...     

水稻秸杆的液化研究

以苯酚和甘油为液化试剂,在浓硫酸催化作用下对水稻秸秆进行液化,讨论了固液比、m苯酚:m甘油、稻秆粒径、催化剂用量、液化时间和温度等因素对液化残渣率的影响.通过正交实验得出最优反应条件:即当固液比为1∶6,浓硫酸用量为3％,在180℃下反应120min,所得残渣率为2.3％.羟值、酸值的测定和红外分析结果表明:液化过程中羟值和酸值都呈现了先增大后减小的趋势,并在反应后期出现酯缩合反应;液化残渣主要为木质素及其衍生物.     

橡胶籽壳无机-有机催化液化及产物的结构表征

以苯酚为液化剂,对橡胶籽壳进行了液化,分析了反应温度,液料比(苯酚与橡胶籽壳的比),催化剂的种类和用量及液化时间对液化反应的影响,同时利用响应曲面设计进行了优化。结果表明:采用V(硫酸)∶m(对甲苯磺酸)=1∶1为催化剂,在反应时间84min,液料比4.0∶1mL/g,液化温度155℃,催化剂的用量为8%时,残渣率为0.48%,液化率为99.52%,几乎完全液化。FTIR分析表明,橡胶籽壳在苯酚的作用下发生了化学反应,致使分子组成(纤维素,半纤维素,木质素等)发生了变化,生成了具有活性官能团的醇类以及酚类物质,同时,伴有新的化合物的生成。     

废纸苯酚液化物制备工艺的研究

采用单因素试验和正交试验研究了废纸的苯酚液化工艺.结果表明:在硫酸催化剂的作用下,废纸可以很好地在苯酚中液化.液化过程的四个影响因素中,液比对液化效果的影响最显著,其次分别为液化时间、催化剂用量和液化温度.废纸苯酚液化的优化工艺为:反应温度150℃、催化剂用量10%、液化时间2.5h、苯酚与废纸质量比(液比)为4.5;在此工艺条件下,液化效率可以达到99.9%.     

一种多胺型纤维素吸附剂的制备

以天然纤维素为原料,制备重金属离子吸附材料.秸秆纤维经过碱化、环氧化、烯胺化,制备了多胺型纤维素,对制备该多胺型纤维素的影响因子如温度、时间、碱浓度、环氧氯丙烷用量、二乙烯三胺用量等进行了分析研究,确定了环氧化的最优条件为:反应温度40℃,环氧氯丙烷与秸秆纤维的质量比5:1,二次碱浓度8%,反应时间15h;烯胺化的最优...     

摩擦材料用线性酚醛树脂的合成工艺研究

以苯酚、甲醛为原料,草酸为催化剂,设计合成摩擦材料基体用线性酚醛树脂。通过正交试验和对比试验,考察线性酚醛树脂的数均分子量、玻璃化转变温度、残炭率等性能,获得其最佳合成工艺条件:苯酚与甲醛物质的量比为1:0.9,催化剂用量为(2.0%按苯酚质量计算),反应时间为4h,反应温度为95℃。     

BPA-PA酚醛环氧树脂导电胶的合成与性能研究

以双酚A多聚甲醛酚醛树脂(BPA-PA酚醛树脂)和环氧氯丙烷为原料,通过亲核取代反应得到BPA-PA酚醛环氧树脂.采用FT-IR、1 HNMR进行结构确证.通过单因素和正交实验得到BPA-PA酚醛环氧树脂的最佳合成工艺条件:在环氧氯丙烷用量为80 g,催化剂用量为0.5 g,反应温度为80℃,反应时间为3 h,10％(...     

竹材废料多元醇液化的工艺研究

对竹材废料在多元醇中的液化反应进行了研究,结果表明,液固比、液化剂组成、液化温度、反应时间及催化剂用量等条件对竹材废料的液化反应具有重要影响。以聚乙二醇-400和丙三醇为混合液化剂,在液固比4∶1、浓硫酸用量为体系质量的4%、温度150℃、时间90min时,液化率可达到95%以上,所得液化产物羟值为350mgKOH/g,黏度750mPa·s,满足制备中强度硬质聚氨酯泡沫的要求。     

四种生物质废弃物环氧树脂的合成及表征

分别以四种生物质废弃物———木粉、榛子壳、稻草和玉米秆苯酚液化物为原料,与环氧氯丙烷反应,制备出以四种生物质液化物为基材的环氧树脂,采用凝胶渗透色谱(GPC)对比分析了四种生物质液化物及其环氧树脂的相对分子量分布。以聚酰胺(PA-650)为固化剂进行固化,并利用热失重分析(TGA)、差热分析(DSC)和剪切强度测试等手段对固化物的热力学性能进行了测试。结果表明,木粉液化物及其树脂的-Mw和-Mn最高分别为532、759和249、308,木粉基树脂胶粘剂的剪切强度最大为5.7MPa,且它的热稳定性最好。     

R-122基环硫树脂的合成与表征

以R-122环氧树脂与硫脲为原料,马来酸酐为催化剂,在水溶液中反应制备R-122基环硫树脂的工艺.研究了反应时间、反应温度对环硫树脂的合成影响规律,确定适合的工艺合成条件为反应温度50℃,催化剂质量为环氧树脂的0.06％,环氧树脂与硫脲的摩尔比为5∶1,反应时间3h,环硫树脂的收率为69.9％.红外光谱和核磁共振分析表...     

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.     

Thixotropy of Systems with Shear Thinning and Plastic Flow Behavior

The definition of the thixotropy is a decrease in viscosity with time in shear and a subsequent recovery of viscosity after the shear deformation is removed.We ...