质子化交联壳聚糖对甲基橙的吸附研究

研究了吸附剂投加量、甲基橙初始浓度、pH值、吸附时间等条件对甲基橙脱色效果的影响。结果表明,在质子化壳聚糖用量为3.6g/L条件下,对质量浓度低于200mg/L甲基橙溶液的吸附率不低于90%。拟二级动力学模型能很好地描述其吸附过程;吸附等温线符合Langmuir模型。质子化壳聚糖在较宽的pH值范围内对甲基橙具有较好的脱色效果,可提高壳聚糖的利用价值。     

硅藻土负载壳聚糖对铬黑T的吸附研究

在静态条件下,研究了硅藻土负载壳聚糖复合吸附剂对铬黑T的吸附性能。通过单因素试验,探讨了吸附剂的用量、吸附时间、负载比、溶液质量浓度以及溶液的pH值等因素对铬黑T吸附效果的影响。在单因素试验的基础上,进行四因素三水平的正交试验。实验结果表明,复合吸附剂中壳聚糖质量分数为19.4%,其吸附效果最好;该材料对pH=5、初始浓度为20mg/L的铬黑T溶液的脱色率可达98.19%,出水色度为2,小于《纺织染整工业水污染物排放标准》(GB 4287—2012)中色度的直接排放限值;吸附模式符合Freundlich公式。     

微波法交联壳聚糖/活性炭复合膜的制备及其吸附性能

采用微波辐射技术制备了交联壳聚糖/活性炭复合膜(CCTS),通过红外光谱和扫描电镜对产物结构进行了表征,研究了该吸附剂的主要性能、吸附机理和对铜离子的吸附条件。结果表明,CCTS复合膜表面粗糙,比表面积较大。壳聚糖的氨基参与了交联反应,CCTS对铜离子的吸附是CCTS的—NH2和—OH与Cu2+发生了配位反应,其吸附符合Langmuir等温方程,属于单分子层吸附。CCTS对铜离子的吸附条件是25℃,pH值为5.5,在50mL浓度为200mg/L Cu2+溶液中,投加0.05g吸附剂,吸附6h,吸附量为117.4mg/g。与水浴法制备的吸附剂相比,该吸附剂的吸附量大大提高,且操作方法简单,工艺条件易于控制。     

APTES改性羧甲基壳聚糖微球对铅离子吸附性能及机理研究

以羧甲基壳聚糖(CMCS)为基体,3-氨基丙基三乙氧基硅烷(APTES)作为改性剂,制备了用于吸附铅离子的改性羧甲基壳聚糖微球(A-CMCS)。使用扫描电子显微镜(SEM)、能谱仪(EDS)、傅里叶红外光谱仪(FT-IR)对吸附剂的表面形貌以及化学组成及结构进行了表征。研究了初始溶液的pH值、吸附温度以及铅离子的初始浓度对A-CMCS吸附性能的影响,结果表明当pH值为5、吸附温度为303 K时吸附剂对铅离子的吸附浓度达到最大为275.2 mg/g,比未改性之前的交联微球的吸附量提升43%。并使用吸附动力学以及等温吸附模型、FT-IR和X射线光电子能谱(XPS)对吸附机理进行了探究,其结果发现A-CMCS微球对铅离子的吸附过程是一个以化学吸附为主的单分子层吸附过程,其中氨基基团在整个吸附过程的起主导作用。     

粉煤灰负载壳聚糖吸附剂处理水中Cr(Ⅵ)的研究

将粉煤灰与壳聚糖复合得到一种负载吸附剂,研究了其对水溶液中Cr(Ⅵ)的吸附,详细探讨了固体吸附剂吸附Cr(Ⅵ)的最佳工艺条件.结果表明,该吸附刺对Cr<Ⅵ)具有较好的吸附性能,最佳吸附条件是:温度为25℃,pH=5,Cr(Ⅵ)初始质量浓度为20mg/L,吸附剂用量为10g/L,吸附时间为1h,Cr(Ⅵ)的去除率可以达到90%以上.     

活性白土/壳聚糖对铜离子吸附作用研究

以活性白土和壳聚糖为原料,通过简单的工艺制得了活性白土/壳聚糖。利用傅里叶红外光谱仪(FT-IR)、热重分析仪(TGA)和X射线衍射仪(XRD)对活性白土/壳聚糖的结构和热稳定性能进行了分析。结果显示,活性白土与壳聚糖形成了稳定结构的复合物,活性白土的层间距增大,说明壳聚糖填充到活性白土的层间结构中,有利于提高吸附作用。以活性白土/壳聚糖为吸附剂,铜离子(Cu2+)溶液为吸附液,研究了吸附条件对吸附剂吸附性能的影响。结果表明,在活性白土与壳聚糖质量比为1∶0.03,吸附时间为30min,吸附剂投加量为0.5g,吸附温度为50℃,溶液pH为6.0的条件下,活性白土/壳聚糖对初始浓度为10mg/L的Cu2+溶液的吸附效果较好,吸附率达到83.2%,显示了活性白土/壳聚糖良好的吸附性能。     

交联黄原酸化壳聚糖树脂对水溶液中棒曲霉素的吸附

以壳聚糖为吸附剂,戊二醛作为交联剂,采用反相悬浮交联法制备球状壳聚糖树脂,利用二硫化碳作为改性剂,在碱性条件下对壳聚糖树脂进行黄原酸化改性,制备成交联黄原酸化壳聚糖树脂(crosslinked xanthated chitosan resin,CXCR)。对CXCR进行红外表征,并研究了其对水溶液中棒曲霉素的吸附性能。结果表明,CXCR在棒曲霉素初始浓度为8 mg/L,CXCR用量为1 g/L,溶液p H值=4,25℃下吸附16 h,吸附量可达6.53 mg/g,可有效地吸附水溶液中的棒曲霉素。CXCR对棒曲霉素的吸附符合拟二级动力学模型;吸附热力学符合Freundlich吸附等温线模型。CXCR有望作为一种新型的材料用于棒曲霉素的吸附,具有广阔的应用前景。     

胶原纤维对水中Cr(Ⅵ)的吸附性能研究

胶原纤维(CF)作为吸附剂去除水中Cr(Ⅵ),研究了CF去除Cr(Ⅵ)时溶液pH值、温度、吸附剂用量和Cr(Ⅵ)初始浓度对去除效率的影响。结果显示,CF对Cr(Ⅵ)的去除率随溶液pH值降低而升高,在pH值为2.0时达到最大,随吸附剂用量增大而增大,随Cr(Ⅵ)初始浓度增加而减小,CF对Cr(Ⅵ)的吸附量随吸附剂用量增加而减小;随Cr(Ⅵ)初始浓度增加而增加,最后趋于稳定。吸附平衡时间为6h,最佳吸附温度为40℃。测定了吸附等温线和吸附动力学曲线,结果表明,Freundlich等温方程能更好地描述CF对Cr(Ⅵ)的吸附,吸附动力学符合伪二级吸附速率方程。FT-IR和SEM-EDS分析表明,CF表面含有大量氨基羧基及羟基等活性官能团,CF对Cr(Ⅵ)的吸附过程存在铬酸根阴离子与质子化活性官能团的静电吸附作用和离子交换作用。     

KCl改性海藻酸钠微球的吸附性能

目的 为了提高海藻酸钠微球的吸附容量和脱色率。方法 以海藻酸钠为原料，共混聚乙烯醇、沸石制备得到一种海藻酸钠微球，在此基础上进行KCl改性，制备得到海藻酸钠微球吸附剂KSPZ(KCl?SA?PVA?zeolite Microsphere)。通过单因素试验得到最佳吸附条件，对吸附前、后样品进行表征，并探究其吸附机理。结果 得到KSPZ的最佳吸附条件，即pH值为9，吸附剂添加量为1 g/L，吸附时间为6 h，亚甲基蓝(Methylene blue，MB)的初始质量浓度为500 mg/L，此时吸附容量为426.63 mg/g，脱色率为85.33%。通过扫描电子显微镜观察到MB被成功吸附在KSPZ表面，其傅里叶红外光谱说明KSPZ与MB之间存在氢键和静电相互作用，且吸附过程符合准二级动力学、Langmuir型等温吸附模型，表明其吸附过程为物理扩散，并伴随着化学吸附。结论 KSPZ是一种稳定性好、脱色率高的吸附剂，为海藻酸钠复合材料在染料废水处理中的应用提供了理论指导。     

UiO-66/壳聚糖的制备及其对U(VI)的吸附机制

铀矿开采和冶炼等工艺产生大量低浓度铀废水,危害着生态环境和人类健康,从含铀废水中去除铀(VI)迫在眉睫。本文以UiO-66、壳聚糖(CS)为原料,采用交联法制备UiO-66/CS新型复合材料,通过静态吸附实验,考察不同pH值、吸附剂投加量、吸附时间及铀初始浓度等外部因素对U(VI)去除率的影响。通过SEM、FTIR、XPS等对UiO-66/CS材料进行表征分析,揭示吸附剂去除U(VI)的机制。结果表明：在铀初始浓度为5 mg/L,温度为298 K,p H为5,投加量为0.15 g/L,吸附时间120 min条件下,UiO-66/CS对U(VI)的去除率可达90.24%。吸附过程符合准二级动力学模型和Freundlich等温吸附模型。U(VI)吸附去除机制主要是-NH、-COOH、Zr-O、-OH等官能团与U(VI)发生络合作用。     

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.……     

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.     

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...     

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 ...