一种模压代木包装材料的制备工艺及性能研究

利用速生杨树木材加工剩余物,制备了一种用于运输包装的代木材料,并研究其物理、机械性能。采用正交试验设计方法制备了不同代木包装材料试样,并利用极差分析方法分析了不同工艺参数对代木包装材料物理、机械性能的影响。试验结果表明,制备代木包装材料的较佳模压工艺参数如下:热压温度为120~125℃、热压时间为10 min、热压压力为10 MPa、胶黏剂的添加质量分数为10%,在此工艺条件下制备的代木包装材料,其静曲强度、内结合强度、吸水厚度膨胀率、密度分别为17.7 MPa,1.61 MPa,6.1%,0.73 g/cm3。所制备的代木包装材料满足国家标准(GB/T4897—1992)的A类刨花板一等品物理力学性能要求,是一种绿色环保的包装材料。     

玉米秸秆纤维缓冲包装材料制备条件优化

针对制备玉米秸秆缓冲包装材料的11个工艺参数,以材料的强度为响应目标,采用Plackett-Burman(PB)与Central Composite Design(CCD)相结合的方法进行筛选优化。PB实验设计与分析表明:纤维粒度、纤维目数与胶粘剂含量为制备工艺的3个关键因素。经过CCD设计及响应面法优化分析得到的制备玉米秸秆纤维缓冲包装材料的最优条件为:纤维粒度224.62目,纤维体积分数22.78%,胶粘剂质量分数35%,材料强度可达1.758 MPa。     

混合植物纤维微波发泡缓冲材料的制备工艺研究

为了探究瓦楞废纸混合纤维与秸秆微波发泡缓冲包装材料制备工艺的关键,以秸秆粉末和B型瓦楞废纸板为基材,通过微波发泡研制出了一种新型环保缓冲包装材料。通过秸秆与瓦楞废纸纤维质量比为变量的单因素试验研究,以及对发泡剂偶氮二甲酰胺(AC)用量、发泡剂碳酸氢铵(NH_4HCO_3)用量、成膜剂聚乙烯醇(PVA)用量3个参数的正交优化试验研究,制备了新型缓冲包装材料。并利用静态压缩试验的方法 ,对该新型缓冲材料的弹性比能的影响因素进行了分析。结果表明:以秸秆与瓦楞废纸纤维质量比为3/5(秸秆纤维15g,瓦楞废纸纤维25g)的原料为主,与约0.5g的PVA,约3g的NH_4HCO_3,约1g的AC进行混合,制成的包装材料的静态压缩缓冲性能较好,且泡孔较均匀。此配方制备的混合植物纤维微波发泡缓冲材料性能优良。     

响应面法优化稻草模塑材料热压工艺参数

目的 探讨热压过程中压力、温度和湿纸胚含水率等因素对稻草秸秆纤维模塑包装材料主要力学性能的影响,确定各因素的权重及最佳工艺参数。方法 采用单因素试验法和响应曲面法,以裂断长和弯曲强度为评价指标,确定最佳工艺条件。结果 最佳热压工艺条件,热压温度为175 ℃,热压压力为6.9 MPa,湿纸胚含水率为70%,此时得到的平均裂断长为7697.93 m,弯曲强度为72.36 MPa,与理论裂断长7712.62 m、弯曲强度71.44 MPa接近,优化结果可信。热压过程中各因素对模塑包装材料裂断长和弯曲强度影响的大小为湿纸胚含水率＞热压压力＞热压温度。结论 过高的温度会造成半纤维素的热解,过高的压力会导致纤维的压溃,过高的含水率产生的能耗过高。适当的热压工艺参数能够降低能耗,保证模塑包装材料的品质及性能。     

挤出法制备生物质包装材料

目的在挤出工艺条件下,以废纸纤维和农作物秸秆为主要原料制备生物质包装材料,研究影响其试样力学性能的主要因素并确定较优配方。方法在废纸和农作物秸秆原料中加入一定量的淀粉、甘油、PVA,经搅拌混合均匀后,通过单螺杆挤出机连续挤出,以实现环保生物质包装材料的连续生产。在单因素实验的基础上,通过正交实验探讨秸秆含量、淀粉含量、PVA含量、甘油含量对材料力学性能的影响。结果在85℃下水浴加热15 min时,混合物料和淀粉之间具有良好的相容性。试样抗压性能的影响因素及主次顺序为淀粉含量PVA含量基材比例甘油含量,试样抗弯性能的影响因素及主次顺序为淀粉含量基材比例PVA含量甘油含量。结论物料分散的均匀性和粘度是以废纸、农作物秸秆为主要原料通过挤出法制备生物质包装材料的关键。当基材比例(秸秆与废纸的质量比)为2︰3,PVA质量分数为2.5%,淀粉质量分数为9%,甘油质量分数为5%时,可获得较优的力学性能。     

环保生物质包装材料的制备及性能研究

目的研究一种环保生物质包装材料的热压成形制备工艺,并对其性能进行评价。方法将凤眼莲作为生物质原材料,通过磨浆并经水浴处理之后,添加助剂配方并经热压成形制备了环保生物质包装材料。将助剂配方、热压温度、热压压力作为影响因素,进行正交试验,选取尺寸稳定性、力学性能、防水性能作为指标,对其性能进行检测和综合评价。结果加入海藻酸钠(0.8%),CMC-Na(0.4%),琼脂(0.8%)作为胶黏剂,尿素(2%)作为增塑剂,乳化石蜡(1%)作为防水剂,在热压温度为150℃,压力为10 MPa条件下制得的生物质包装材料具有较好的综合性能。结论通过加入环保助剂配方,采用热压工艺可以制备出性能良好的生物质包装材料。     

添加花生秸秆的无胶纤维板的制备工艺及优化

目的为了提高花生秸秆的回收利用率,并为花生秸秆纤维提供一种可行的处理方式,将其与木纤维一起热压制备无胶纤维板。方法不添加胶黏剂,用热压成型技术将花生秸秆制备纤维板。分别以热压温度、压力、时间和花生秸秆添加量等4个因素进行单因素试验,再通过三因素三水平响应面实验进行工艺优化。结果响应面模型P0.01,失拟项P=0.48960.05,模型回归系数R~2=0.9867;响应面优化得到了最佳工艺条件,即热压温度为170℃、热压压力为8MPa、热压时间为6min、花生秸秆质量分数为20%,此条件下静曲强度值最大,为10.1815 MPa。结论回归模型达到极显著水平,模型失拟度不显著,表明模型相关度好。在最佳工艺条件下进行验证试验得到的静曲强度数值为(10.182 33±0.157)MPa,与预测值接近,表明优化工艺可靠。     

微米木纤维形成轻质人造板材MLFB的实验研究

利用微米级长木纤维在实验室成功地压制了轻质人造板材,所得板材外观呈现木本色,其某些物理力学性能达到<日本轻质刨花板工业标准JISA5908>,从而验证了微米级木纤维形成高强度纤维板的细胞裂解理论,并通过对热压过程中影响板材力学性能的主要因子的分析,得到实验室的较佳工艺参数:热压温度120℃,热压压力2.5MPa,热压时间0.3min/mm,施胶量15%(质量分数).     

木基免拆保温建筑模板制备及其性能研究

以木材加工剩余物碎料和自制无机胶粘剂为原料,通过热压工艺制备木基免拆保温建筑模板。研究了施胶量、热压时间、热压温度及板材密度对其性能的影响。结果表明,试验范围内,随着施胶量、密度的增大,木基免拆保温建筑模板的抗折强度、弹性模量、软化系数、导热系数逐渐增大,抗冻性能增强;随着热压温度、热压时间的增加,木基免拆建筑模板的抗折强度、弹性模量、软化系数先增大后减少,导热系数逐渐下降,抗冻性能先上升后下降。通过分析获得木基免拆保温建筑模板优化制板工艺参数:密度为0.9g/cm3,施胶量为65%,热压温度为120℃,热压时间为12min。     

基于老化性能的稻壳/木刨花复合包装箱板的优化工艺

目的 为了提高我国农林剩余物资源的利用率,解决我国绿色包装材料的市场需求,研究外包装箱板材料的制备工艺与组分参数。方法 以稻壳和木质刨花为主要原料,以酚醛树脂和异氰酸酯为胶粘剂,采用热压方法制备外包装箱用复合板;采取WCAMA六循环老化方法对试件进行处理,并对老化处理后的复合板进行内结合强度、静曲强度和弹性模量等力学性能的宏观分析和材料组分变化的微观分析。结果 当表层施胶量质量分数为8%、芯层施胶量质量分数为11%、密度为0.9 g/cm3和防水剂含量为0.6%时,复合板的内结合强度、静曲强度和弹性模量保留率在50%以上,具有良好的耐老化性能。结论 基于老化性能得出的制备工艺及组分参数可对绿色环保、经济性好、可持续发展的稻壳-木刨花外包装箱板材料的开发提供理论与实践支撑。     

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 ...