乳化炸药不合格品再处理敏化参数的研究

为了研究敏化剂添加量及敏化温度对乳化炸药不合格品处理的影响，建立了独立的乳化炸药不合格品处理生产线，对乳化炸药不合格品进行了返工处理试验及生产运行。根据试验及生产运行结果,确定了返工乳化炸药不合格品处理过程中的敏化工艺参数:发泡剂和促进剂尿素添加质量分别占混合基质质量的0.20%~0.26%和0.06%~0.10%，敏化温度控制在44~54 ℃，敏化后样品密度控制在1.10~1.24 g/cm³。为了验证敏化工艺参数的合理性，对返工后的乳化炸药的爆速、猛度及殉爆距离进行了试验测试。测试结果表明，返工后乳化炸药的性能均符合乳化炸药的质量要求。     

乳化炸药的高原环境适应性研究

通过模拟高原环境,研究温度与气压的变化对乳化炸药爆速、猛度的影响,并通过显微镜观察乳化炸药的微观结构,研究其性能改变的原因,以利于指导高原地区乳化炸药的使用以及爆破参数的设计。实验结果表明:若温度为0 ℃不变时,海拔不超过2 500 m,乳化炸药的性能基本保持不变;海拔为2 500 m以上时,乳化炸药性能会迅速降低。而若温度随着海拔高度的增加而降低时,乳化炸药的爆速、猛度会迅速降低。在海拔为2 500~3 500 m时,化学敏化的乳化炸药敏化气泡开始转变为无效气泡。     

树脂微球敏化乳化炸药技术研究

对比了乳化炸药敏化技术的现状,提出了树脂微球可作为乳化炸药的物理敏化剂,并通过试验数据分析了采用树脂微球敏化的乳化炸药密度、爆炸性能、黏度、泵送稳定性、储存稳定性,来评价树脂微球作为乳化炸药敏化剂的敏化效果。结果表明:树脂微球的质量占乳胶基质质量的0.35%~0.45%时,制备的乳化炸药密度为1.09~1.15 g/cm3,爆速为5 200~5 400 m/s,殉爆距离为6~9 cm;高温80℃左右时,树脂微球敏化的乳化炸药黏度略高于化学敏化的乳化炸药,远小于膨胀珍珠岩敏化的乳化炸药;树脂微球敏化的乳化炸药泵送稳定性优于化学敏化及膨胀珍珠岩敏化的乳化炸药。     

不同敏化材料的乳化炸药抗深水压力性能的实验研究

对化学敏化、珍珠岩敏化、玻璃微球敏化的3种乳化炸药进行了抗深水压力的实验研究,在压力值达到0．2MPa,3种炸药的爆速分别下降了74．81％、33．28％、11．75％,猛度分别下降了49％、27．49％、17．95％,在压力值达到0．3MPa,测试珍珠岩敏化和化学敏化乳化炸药的爆速时就出现了半爆或拒爆。实验结果表明：在开始阶段,3种炸药爆炸性能随水深的增加下降幅度都较大;随着水深的继续增加,玻璃微球和珍珠岩敏化的乳化炸药的爆炸性能下降幅度变缓,而化学敏化的乳化乳化炸药爆炸性能下降幅度继续增大;3种炸药抗压性能由优到劣的大致顺序是玻璃微球敏化,珍珠岩敏化,化学敏化的乳化炸药。     

添加复合稀释剂的低爆速乳化炸药的制备及性能

以玻璃微球和滑石粉共同作为稀释剂制备一种低爆速乳化炸药。观察不同质量分数的玻璃微球和滑石粉对乳化炸药形貌的影响,并对乳化炸药的爆速、猛度、空中爆炸冲击波压力及储存稳定性进行测试。实验结果表明,随着滑石粉质量分数的增加,乳化炸药的形貌由乳胶状逐渐向颗粒状转化,爆速呈线性下降,对玻璃微球质量分数为5%、10%、15%的乳化炸药,测得最低爆速分别为3 440、2 740、2 188 m/s。而随着滑石粉质量分数的增加,猛度、空中爆炸冲击波峰值超压均呈非线性下降,当滑石粉控制在一定量时,冲击波正压作用时间变化不大,乳化炸药储存稳定性较好。这种低爆速乳化炸药成本低廉、爆轰性能可调、储存稳定性好,具有较好的实用性。     

低爆速炸药破碎混凝土块的试验

用低爆速炸药与乳化炸药对两种尺寸的混凝土块进行了爆破实验,并对破碎效果进行了比较。结果表明,低爆速炸药的猛度和爆力都明显小于乳化炸药。这印证了低爆速炸药所具备的低猛度、低爆力的性能特点,有利于在复杂环境中用于爆破拆除基础等构筑物。     

低爆速炸药破碎混凝土块的试验

用低爆速炸药与乳化炸药对两种尺寸的混凝土块进行了爆破实验,并对破碎效果进行了比较。结果表明,低爆速炸药的猛度和爆力都明显小于乳化炸药。这印证了低爆速炸药所具备的低猛度、低爆力的性能特点,有利于在复杂环境中用于爆破拆除基础等构筑物。     

发泡剂及促泡剂对乳化炸药爆速的影响

为了研究发泡剂和促泡剂含量对乳化炸药发泡速度和爆速的影响,对不同含量下发泡剂和促泡剂进行了密度测量和爆速实验。结果表明:在相同含量促泡剂和相同发泡时间下,乳化炸药爆速随着发泡剂含量的减小而减小,发泡速度同样减小;在发泡剂含量相同时,随着发泡时间的不同,促泡剂的含量对乳化炸药爆速及发泡速度的影响不同。当促泡剂含量在一定范围内,发泡时间不充足时,乳化炸药爆速随促泡剂含量增加而增加,发泡速度也增加;当发泡时间充足时,乳化炸药爆速不随促泡剂含量的变化而变化。当促泡剂含量超过一定范围时,乳化炸药爆速不随促泡剂含量的变化而变化,发泡速度同样没变化。     

发泡剂及促泡剂对乳化炸药爆速的影响

为了研究发泡剂和促泡剂含量对乳化炸药发泡速度和爆速的影响,对不同含量下发泡剂和促泡剂进行了密度测量和爆速实验。结果表明:在相同含量促泡剂和相同发泡时间下,乳化炸药爆速随着发泡剂含量的减小而减小,发泡速度同样减小;在发泡剂含量相同时,随着发泡时间的不同,促泡剂的含量对乳化炸药爆速及发泡速度的影响不同。当促泡剂含量在一定范围内,发泡时间不充足时,乳化炸药爆速随促泡剂含量增加而增加,发泡速度也增加;当发泡时间充足时,乳化炸药爆速不随促泡剂含量的变化而变化。当促泡剂含量超过一定范围时,乳化炸药爆速不随促泡剂含量的变化而变化,发泡速度同样没变化。     

模拟高原环境下黏度对乳化炸药性能影响

为研究乳化基质黏度对乳化炸药在高原地区的性能影响,选取4种高黏度蜡制备乳化炸药,经过不同海拔高度的模拟储存,测试了乳化基质黏度、粒径、电导率及敏化气泡变化并对模拟后爆速与猛度进行分析。实验结果表明,在海拔高度500 m以下时,乳化炸药性能几乎不发生变化;海拔高度在2 500 m以上时,乳化炸药开始明显析晶,爆炸性能显著下降。当模拟储存环境从海拔高度0 m上升到4 500 m时,4种乳化基质的粒径没有发生显著变化,化学敏化的乳化炸药的敏化气泡扩散聚集程度与黏度呈负相关。微晶蜡、白蜂蜡、混合蜡、5#复合蜡所制备的乳化炸药的电导率增长率分别为：68.18%、18.18%、13.64%、4.55%,猛度分别下降：21.87%、8.72%、6%、13.56%,爆速分别下降：19.21%、4.43%、3.23%、10.82%。表明在高原地区乳化炸药生产时,在一定范围内提高乳化基质黏度,能够有效提升乳化炸药稳定性。     

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.……     

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.     

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.     

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 ...