Numerical simulation of brittle fracture of thin-walled structures1

The model of brittle material, allowing for the determination of initiation and growth of cracks in thin-walled structures up to their destruction, is offered. Solutions of some problems are submitted: destruction of a plate at a homogeneous stress state; destruction of a beam at a pure bending; dynamic deformation and destruction of a plate with the concentrated mass having various initial speeds. Destruction of part of the material of the plate is shown to result in dynamic loss of stability of the solution.     

On the strength of a body at temperatures close to its melting point

On the example of frozen soils and ice existing at temperatures close to the melting point, the existence of two mechanisms (types) of destruction related to the phase transitions of water is shown. The first mechanism that operates near the melting point is plastic destruction, it gradually converts an ice body into a liquid-like state. The second mechanism operating far from the melting point is brittle destruction, disintegration into parts, with a slight preliminary deformation. For both types of destruction equations of long-term strength and of the behavior of deformation in time have been obtained.     

基于MATLAB技术的LPG储罐重大事故动态模拟评价系统开发与应用

为提高人们对LPG储罐重大事故预测、预防水平和抗灾害能力,根据LPG储罐泄漏、扩散、着火、爆炸等事故的发生和发展,建立一套LPG储罐重大事故动态模拟评价方法,在此基础上进行软件系统的功能、模块和数据设计,应用VC与MATLAB可视化面向对象接口技术实现事故后果模拟评价及特征参数随时间、距离变化过程的可视化。该软件能够脱离MATLAB环境运行,实现了评价结果通过图形直观动态显示,可预测特定位置的破坏情况,评价事故影响范围和危害程度。工程应用表明,该评价系统软件用于LPG储罐重大事故的安全评价是可行的,并可用于其他具有着火和爆炸危险性、毒性的重气或液化气体的生产和贮存企业的安全评价。     

废旧炮弹销毁设计与施工

为彻底消除安全隐患、稳定社会治安,某市集中销毁了各类收缴的废旧炮弹。本文阐述了弹药销毁的设计和施工组织过程,包括待销毁炸弹种类鉴定、销毁场地选择、炸弹运输、诱爆药量计算、布弹装药、起爆网路、安全措施、施工组织等内容。经过精心设计和运作,废旧炸弹销毁获得圆满成功,为类似工作提供了有益的经验。     

废旧炮弹销毁设计与施工

为彻底消除安全隐患、稳定社会治安,某市集中销毁了各类收缴的废旧炮弹。本文阐述了弹药销毁的设计和施工组织过程,包括待销毁炸弹种类鉴定、销毁场地选择、炸弹运输、诱爆药量计算、布弹装药、起爆网路、安全措施、施工组织等内容。经过精心设计和运作,废旧炸弹销毁获得圆满成功,为类似工作提供了有益的经验。     

Novel hybrid ultrahard material

A novel hybrid ultrahard polycrystalline composite material has been produced by the reinforcement of the polycrystalline diamond composite thermostable material with a CVD grown polycrystalline diamond. It has been found that a thermal treatment of a polycrystalline diamond grown at high pressure ensures an increase of the CVD diamond hardness from 77 to 140 GPa. Tests of drilling tools have shown that in turning granite of the XI drillability index the wear intensity of rock destruction elements of the hybrid ultrahard material is lower than that of rock destruction elements of polycrystalline diamond composite thermostable material by a factor of 14.     

Stimulation of the diamond nucleation on silicon substrates with a layer of a polymeric precursor in deposition of diamond films by microwave plasma

It has been shown that layers of a certain type of polymers applied to silicon substrates at the thermal destruction form (in parallel with sp² coordinated carbon) diamond nanoparticles, which act as nucleation centers of crystallites in the subsequent chemical vapor deposition of diamond. Microcrystalline diamond films have been synthesized from methane-hydrogen mixtures by microwave plasma using poly(naphthylhydrocarbyn) and poly(hydrocarbyn) preceramic polymers.     

Current-induced destruction of type I superconductivity: The role of the one- and two-dimensional mixed state

New experimental and theoretical results on the current-induced phase transition in cylindrical wires (tin) are presented: The London model for the intermediate state of current-carrying superconductors has been modified, taking into account magnetoresistance, and has been extended to hollow cylinders. Evidence for the one- and two-dimensional mixed state first proposed by Landau has been obtained from the study of the quasistatic voltage-current curves of solid and hollow cylindrical specimens, respectively. The kinetic phenomena during the current-induced destruction of superconductivity in solid cylindrical wires have previously been studied by Posada and Rinderer, but only measurements on hollow wires of high purity presented in this paper confirm the isothermal electromagnetic theory of Rothen and Bestgen for a current-induced phase transition. For currents close to Silsbee's critical current, in pure specimens as well as for impure specimens, for any current above the critical, the dynamic destruction of superconductivity in wires is no longer isothermal. For these cases the nonisothermal theory of Posada and Rinderer has been extended to the case of hollow cylinders and successfully compared with experiments.This work was supported financially by the Fonds National Suisse pour la Recherche Scientifique.     

Peculiarities of formation of phase composition,porous structure,and catalytic properties of tungsten oxide-based macroporous materials fabricated by sol–gel synthesis

The method of template sol–gel synthesis of tungsten oxide-based macroporous materials using ‘core–shell’ latex particles as colloid templates is described. The chemical composition and structural characteristics of the synthesized macroporous oxide systems have been investigated. The peculiarities of formation of material phase composition and macroporous structure under different template thermal destruction conditions have been revealed. An optimal method of a targeted synthesis of the crystalline tungsten(VI) oxide having a defect-free macroporous structure (average pore size 160 nm) and efficient catalytic properties under organic liquid phase oxidation conditions has been suggested. The prospects of the fabricated material application as catalysts of hydrothermal oxidation of radionuclide organic complexes at radioactive waste decontamination have been demonstrated.     

Multi-objective optimization of a cooling tower assisted vapor compression refrigeration system

A cooling tower assisted vapor compression refrigeration machine has been considered for optimization with multiple criteria. Two objective functions including the total exergy destruction of the system (as a thermodynamic criterion) and the total product cost of the system (as an economic criterion), have been considered simultaneously. A thermodynamic model based on energy and exergy analyses and an economic model according to the Total Revenue Requirement (TRR) method have been developed. Three optimized systems including a single-objective thermodynamic optimized, a single-objective economic optimized and a multi-objective optimized are obtained. In the case of multi-objective optimization, an example of decision-making process for selection of the final solution from the Pareto frontier has been presented. The exergetic and economic results obtained for three optimized systems have been compared and discussed. The results have shown that the multi-objective design more acceptably satisfies generalized engineering criteria than other two single-objective optimized designs.     

沥青路面早期破坏研究

沥青路面的破坏形式是多种多样的，而沥青路面的早期破坏是指路面在尚未达到使用年限之前发生的破坏，这种现象越来越具有普遍性。本文归纳了沥青路面早期破坏的类型、分析其破坏原因并探讨了防治措施。     

Remediation of TCE contaminated soils by in situ EK-Fenton process

The treatment performance and cost analysis of in situ electrokinetic (EK)-Fenton process for oxidation of trichloroethylene (TCE) in soils were evaluated in this work. In all experiments, an electric gradient of 1V/cm, de-ionized water as the cathode reservoir fluid and a treatment time of 10 days were employed. Treatment efficiencies of TCE were evaluated in terms of the electrode material, soil type, catalyst type, and catalyst dosage and granular size if applicable. Test results show that graphite electrodes are superior to stainless steel electrodes. It was found that the soil with a higher content of organic matter would result in a lower treatment efficiency (e.g. a sandy loam is less efficient than a loamy sand). Experimental results show that the type of catalyst and its dosage would markedly affect the reaction mechanisms (i.e. "destruction" and "removal") and the treatment efficiency. Aside from FeSO4, scrap iron powder (SIP) in the form of a permeable reactive wall was also found to be an effective catalyst for Fenton reaction to oxidize TCE. In general, the smaller the granular size of SIP, the lower the overall treatment efficiency and the greater the destruction efficiency. When a greater quantity of SIP was used, a decrease of the overall treatment efficiency and an increase of percent destruction of TCE were found. Experimental results have shown that the quantity of electro-osmotic (EO) flow decreased as the quantity of SIP increased. It has been verified that the treatment performances are closely related to the corresponding EO permeability. Results of the cost analysis have indicated that the EK-Fenton process employed in this work is very cost-effective with respect to TCE destruction.     

On the structure formation of diamond-containing composites used in drilling and stone-working tools (A review)

The publications on the studies of structures and properties of diamond-containing composites (diamond–(WC–Co), diamond–(Fe–Cu–Ni–Sn), diamond–(Co–Cu–Sn) and diamond–hard alloy plates used to produce tools for drilling oil and gas wells as well as stone-working tools have been analyzed. Particular attention has been given to the structure formation of the diamond–matrix transition zone, mechanical and operating properties of the composites. The promising lines of the development of the materials science of diamond-containing composites used in rock destruction tools have been defined.     

A life cycle assessment of destruction of ammunition

The Swedish Armed Forces have large stocks of ammunition that were produced at a time when decommissioning was not considered. This ammunition will eventually become obsolete and must be destroyed, preferably with minimal impact on the environment and in a safe way for personnel. The aim of this paper is to make a comparison of the environmental impacts in a life cycle perspective of three different methods of decommissioning/destruction of ammunition, and to identify the environmental advantages and disadvantages of each of these destruction methods: open detonation; static kiln incineration with air pollution control combined with metal recycling, and a combination of incineration with air pollution control, open burning, recovery of some energetic material and metal recycling. Data used are for the specific processes and from established LCA databases. Recycling the materials in the ammunition and minimising the spread of airborne pollutants during incineration were found to be the most important factors affecting the life cycle environmental performance of the compared destruction methods. Open detonation with or without metal recycling proved to be the overall worst alternative from a life cycle perspective. The results for the static kiln and combination treatment indicate that the kind of ammunition and location of the destruction plant might determine the choice of method, since the environmental impacts from these methods are of little difference in the case of this specific grenade. Different methods for destruction of ammunition have previously been discussed from a risk and safety perspective. This is however to our knowledge the first study looking specifically on environmentally aspect in a life cycle perspective.     

The limiting state of force systems and processes of damage of them. Report 1. Energy criteria of failure

A composite energy criterion of failure of a force system in relation to test temperature and level of normal and frictional stresses is proposed and a method has been developed for separation from the full mechanical and thermal energy of their effective portions expended on formation and accumulation of damages. The concept has been introduced of the parameters of interaction of different constituents of the effective energy and a method is given for evaluation of them. Particular criteria of thermal force failure have been obtained and understandings of the limits of (mechanical) destruction and of temperature destruction have been introduced. On the basis of experimental results satisfactory correspondence to the test data of the thermal force criterion in the 4 K to T _melt range has been established for nickel and aluminum and an analysis has also been made of the change in mechanisms of damage of these materials in connection with varying of the level of stresses and test temperature.Translated from Problemy Prochnosti, No. 1, pp. 11–23, January, 1993.     

Technologies for the removal of phenol from fluid streams: a short review of recent developments

The available technologies for the abatement of phenol from water and gaseous streams are briefly reviewed, and the recent advancements summarized. Separation technologies such as distillation, liquid–liquid extraction with different solvents, adsorption over activated carbons and polymeric and inorganic adsorbents, membrane pervaporation and membrane–solvent extraction, have been discussed. Destruction technologies such as non-catalytic, supercritical and catalytic wet air oxidation, ozonation, non-catalytic, catalytic and enzymatic peroxide wet oxidation, electrochemical and photocatalytic oxidation, supercritical wet gasification, destruction with electron discharges as well as biochemical treatments have been considered. As for the abatement of phenol from gases, condensation, absorption in liquids, adsorption on solids, membrane separation, thermal, catalytic, photocatalytic and biological oxidation have also been considered. The experimental conditions and the performances of the different techniques have been compared.     

利用抗爆小间销毁雷管的方法

介绍了在抗爆小间内引爆方式销毁雷管的技术和安全事项。用该法销毁了 7万余发成品或半成品雷管。该法与常规方法略有不同 ,适合销毁数量较大但没有销毁场地的销毁作业。作者结合参加中日两国在黑龙江省北安市清理挖掘日军在二战期间遗弃化学武器的作业实践 ,对销毁弹药的环境保护提出了思考 ,认真研究销毁技术并借鉴国外的先进技术 ,尽可能减少销毁作业对环境的破坏是非常必要的     

利用抗爆小间销毁雷管的方法

介绍了在抗爆小间内引爆方式销毁雷管的技术和安全事项。用该法销毁了 7万余发成品或半成品雷管。该法与常规方法略有不同 ,适合销毁数量较大但没有销毁场地的销毁作业。作者结合参加中日两国在黑龙江省北安市清理挖掘日军在二战期间遗弃化学武器的作业实践 ,对销毁弹药的环境保护提出了思考 ,认真研究销毁技术并借鉴国外的先进技术 ,尽可能减少销毁作业对环境的破坏是非常必要的     

Progress in cryosurgery

Cryosurgery (in situ freezing), the controlled cryogenic destruction of tissues in situ rather than their removal by conventional surgical excision, has been efficaciously employed for the treatment of numerous benign and malignant neoplasms. Studies have indicated the participation of an immunologic response to antigens of the frozen tissue, ie cryoimmunization, as contributing to cryodestruction. Following a cursory overview of the background and rationale for studies of the immunologic phase of cryodestruction, consideration is given to recent experimental and clinical studies contributing to our further understanding and application of cryoimmunization as a therapeutic modality.     

层压减振复合钢板的拉伸剪切特性

本文选用1.67×10-2、1.67×10-3、1.67×10-4、1.67×10-5s-1四种形变速率,在20～150℃试验温度范围内研究了用酚醛树脂氯丁胶作夹层的层压减振复合钢板的拉伸剪切特性。结果指出,在较低温度和较高形变速率下,层压减振复合钢板具有较高的拉伸剪切强度,其破坏形态呈高聚物撕裂和界面破坏的混合破坏特征;在80℃附近,拉伸剪切强度最低,其破坏形态为具有滑移特征的高聚物内聚破坏;在80～150℃温度范围内,随温度升高,拉伸剪切强度增加,这是由于高聚物夹层材料中的氯丁橡胶发生了交联反应的缘故。