注流孔结构对中间包流场影响的物理模拟

针对某钢厂十流中间包紊流抑制器注流孔结构不合理引起流场分布差、各流铸坯质量不均的问题,运用相似原理,使用相似比为1:3的物理模型进行水模型实验,设计不同的注流孔结构研究流体在中间包的平均停留时间曲线及流场显示特征,明晰注流孔结构对中间包流场的影响规律,优化紊流抑制器注流孔结构,达到中间包流场优化及浸入式水口各流一致性提高的目标。结果表明,长距离多流中间包在无堰坝结构条件下,紊流抑制器的注流孔内径尺寸、数量及开孔方向对中间包流场都有影响,注流孔内径的影响最为显著,数量次之。设计的最佳注流孔内径由原型的53 mm缩小至30 mm,死区比例由54.05%降至34.69%,F曲线最大标准差由0.0154降低至0.0035,中间包流场得到改善,各流一致性显著提高。当注流孔数量由1个增加至3个,死区比例由34.69%增大至46.05%,F曲线最大标准差由0.0035增大到0.0062,注流孔数目越多,流场死区比例反而越大,各水口流场的一致性越差。对长距离多流中间包,建议主要通过适当改变注流孔内径及减少孔数来改善中间包流场,提高各流一致性。     

Influence of capillary condensation on heat and mass transfer in the grain of a Fischer-Tropsch synthesis catalyst

A mathematical model of heat and mass transfer processes in the grain of the Fischer-Tropsch synthesis catalyst is presented that takes into account the effect of the capillary condensation of the products of the synthesis in the pores of the catalyst. The influence of capillary condensation on the processes of the diffusion transfer of heat and mass in the catalyst grain is analyzed using the proposed model. Dependences of the efficiency factor of the grain on the pressure and temperature of the process and the partial pressure of various components of a mixture are presented. The possibility of determining the optimum pressure and temperature of carrying out the process for the catalyst of a certain structure is shown.     

含缩水甘油基／氨基丙烯酸酯共聚物乳液的聚合稳定性

研究了乳胶粒组成对含有缩水甘油基,羧基和胺基的丙烯酸酯多层核壳型乳液聚合稳定性的影响规律,探讨了聚合过程的凝聚机理。研究表明：官能团间的交联凝聚作用和水溶性聚合物的架桥凝聚作用是本体系凝聚物形成的主要原因。     

An increase in thermodynamic efficiency and compactness of contact apparatuses via spatially organized structure of the active material bed

The possibility of filling the hollow input (diffuser) and output (confuser) sections of contact apparatuses by an active material is analyzed. The equation determining the distribution function of the sizes of material particles along the axis of a conelike apparatus, which provides the minimum volume of the bed of particles at the specified values of the total surface area of the interfacial contact in the bed and total flow resistance of the bed, is derived. It is shown that the change in the conventional shape of the apparatus to a construction in the form of a junction of two truncated cones filled with the active material allows one to decrease the total volume of the apparatus by 30%. The dependence of the thermodynamic efficiency and compactness of the regenerative facility on the particle size of the active material bed is numerically analyzed. The existence of a critical particle size which determines the minimum necessary volume of the bed providing high thermodynamic efficiency of the process is shown.     

Manifestation of the Urbach rule in the fundamental electronic absorption spectra of halide salt melts: I. Tails of the absorption edge of alkali metal halide melts

The long-wavelength tails of the fundamental electronic absorption spectra of alkali metal halide melts have been investigated. The obtained values of the absorption characteristics of the alkali metal halide melts have confirmed the assumption that, over a wide temperature range (600–900°C), the exponential tail of the absorption coefficient of these disordered systems is associated with the presence of the spectrum of fluctuating electronic levels extended to the band gap in the melts under investigation. The fulfillment of the Urbach rule is the limiting case of the general exponential dependence of the optical absorption coefficient in the ultraviolet region of the fundamental absorption edge. In the studied series of melts of alkali metal halide salts, the absorption coefficient in the region of tails of the spectral curves of the halide systems decreases from LiCl to CsCl and from LiCl to LiI. An analysis of the results obtained from the investigation of alkali metal halides has revealed an interrelation between the main parameters of the Urbach rule and between these parameters and the temperature coefficient of the band gap.     

玻璃纤维增强制件注射成型过程的模具磨损原因及规律

玻璃纤维增强聚醚酰亚胺（PEI）薄壁制件注射成型过程中,易对模具型芯产生磨损,从而严重影响制件成型品质。以某型号手机听筒薄壁制件为例,根据生产实践分析了型芯表面的微观磨损特性,采用数值计算方法研究了型腔近壁面的熔体流动行为以及型芯表面材料的冲蚀破坏形式与磨损规律。结果表明,注塑过程中型芯表面材料发生冲蚀磨损形成月牙形凹槽,型腔近壁面上的熔体流速决定了月牙形凹槽的形貌和尺寸,玻璃纤维粒子的入射角和倾角决定了型芯表面材料的冲蚀破坏形式,冲蚀磨损量随着玻璃纤维粒子侧倾角的增大不断增加,随着入射速度的增大呈指数型增加。     

The electrochemistry of alloys

The features of the dissolution of the components of alloys forming solid solutions were examined. It was shown on the example of the anodic dissolution of alpha-brass that the process of the selective dissolution of zinc observed in the initial period is limited by the stage of its non-stationary diffusion from the bulk of the alloy and is subsequently replaced by uniform dissolution. During prolonged corrosion of brass, secondary selective dissolution is observed, which is due to the re-deposition of copper.It was established that intensive preferential dissolution of iron from Fe-Cr alloys takes place in the passive region and leads to the enrichment of the passivating chromium film. The results obtained from an investigation of the dissolution of the components of Fe-Cr-Mo alloys in the active region permit the conclusion that the favourable effect of small additions of molybdenum on the corrosion stability of alloys is due to the fact that this element, in view of its great inclination to passivation, blocks the most active centres of the surface in the process of its dissolution.In order to establish the mechanism of the active dissolution of Fe-Cr, alloys, the effect of the potential and pH of sulphate solutions on the partial dissolution rates of iron and chrome from these alloys in the active state was established. It was shown that the Tafel slopes and the order of magnitude of the reaction for the H⁺ ions for both components were the same and close to the corresponding values for pure iron (at low concentrations of chromium in the alloy) or for pure chromium (when the chrome content in the alloys was 13% or more). A mechanism was suggested for the active dissolution of alloys that explained the discovered regularities.     

Mathematical description of the synthesis of butadiene rubber with allowance for the branching of a polymer under conditions of the separate supply of a reaction mixture to the reactors of a cascade

Mathematical modeling of the synthesis of butadiene rubber on a neodymium-based catalytic system under conditions of the separate supply of a reaction mixture to the apparatuses of a cascade is performed. Expressions are derived for calculating the characteristics of the branching of the polymer with allowance for the additional supply of the reaction mixture to the second apparatus of the cascade. An analysis of the influence of the flow rate of an additional stream of the reaction mixture to the second apparatus of the cascade and operating parameters on the molecular weight characteristics and branching of the polymer is performed.     

水泥预粉磨装备及技术发展现状的分析

重视预粉磨装备及技术的发展,就是重视水泥联合(半终)粉磨工艺系统的粉磨效果。联合(半终)粉磨系统中充分利用了料床预粉磨段粗处理的技术特性,同时发挥了管磨机段独有的磨细与整形功能,真正实现了“分段粉磨”过程中两段之间的优势互补。预粉磨段主机的吸收功耗越大,管磨机段主电机电耗降低越多,系统的总节电效果越显著。随着预粉磨段主电机功率与管磨机主电机装机功率比值的增加,预粉磨段处理能力进一步增大,投入的功耗越多,整个粉磨系统电耗降低的幅度也更大。在水泥粉磨生产线改造过程中,将高压力多辊外循环立磨用于预粉磨段,是降低粉磨电耗的发展方向之一。辊压机联合(半终)水泥粉磨系统中辊压机的吸收功耗至少应≥9.0 kWh/t,高值可以达到12.0 kWh/t,在此范围内越高越好。辊压机联合(半终)粉磨系统中,辊压机运行常常表现为不够平稳、时有偏辊现象发生、液压系统压力输出不稳定、操作不灵敏、液压系统现场“跑冒滴漏”严重、控制关键元器件购置困难等。建议采用辊压机SPC控制系统进行改造,以确保辊压机应保持稳定和较高的工作压力,确保良好的挤压做功能力,确保有更多的细粉产出,有利于系统高效低耗运行。     

Die differentielle Doppelschichtkapazität an der Phasengrenze Quecksilberanorganischer Elektrolyt—II. Das Kapazitätsminimum

In the negative range of charge, the differential double-layer capacitance at the interface of mercury and an inorganic electrolyte solution shows a characteristic minimum. This minimum is independent of the nature of the ion, of the concentration of electrolyte and of the temperature. However, the solvent strongly influences the capacitance of the minimum. The metal charge at which the minimum occurs is uninfluenced only by the temperature. Changes of the concentration of the electrolyte as well as of the nature of the anion are able to cause a shift of the minimum.     

硼酸钙对铜渣中夹杂铜沉降效果的影响

考察了添加剂CaB2O3对转炉铜渣中夹杂铜沉降效果的影响，并结合铜渣的粘度测试及红外光谱表征，研究其影响机理，采用FactSage软件计算了添加剂对铜渣液相线温度的影响。结果表明，随添加剂含量增大，铜渣中夹杂铜的沉降效果逐渐增强，添加剂含量由0增至6wt%时，底部渣含铜量由4.10wt%增至6.85wt%，这是由于添加剂可有效降低铜渣粘度。随添加剂含量增大，渣粘度降低，但降低效果随温度增大而趋于平缓。随添加剂含量增大，铜渣的硅酸盐结构趋于简化，添加剂通过破坏铜渣复杂的硅酸盐结构降低铜渣粘度。铜渣的液相线温度随添加剂含量增大而减小，添加剂通过减少渣中固体颗粒的方式降低铜渣粘度。     

填充型NBR/EPDM导电复合材料的研究

研究了石墨/炭黑填充的NBR/EPDM导电复合材料力学性能、动态力学性能和压阻、温阻特性。结果表明,随NBR用量的减少,复合材料拉伸强度、撕裂强度和拉断伸长率均降低;与纯胶相比,填料在NBR/EPDM中分散性变差,复合材料Payne效应和损耗因子都增大。电阻率测试结果表明,NBR/EPDM并用胶电阻率明显低于纯胶;恒温下其电阻率随压力的增大先减小后增大;恒压下其电阻率随温度的升高而减小;NBR/EPDM并用比不同时,复合材料电阻率随压力、温度的变化趋势不尽相同。     

Viscosity of cottonseed meal dispersions

Summary It has been shown that the apparent viscosities of cottonseed meal dispersions depend on the concentration of meal in the dispersion, the concentration of sodium hydroxide in the dispersion, and the addition of trichloroacetate ion and that the viscosities of the glue dispersions are independent of the nitrogen solubilities of the protein contained in the meal and, for the processes evaluated, independent of the method of removal of the oil to produce the meal. One of the laboratories of the Bureau of Agricultural and Industrial Chemistry, Agricultural Research Administration, U. S. Department of Agriculture.     

Scientific foundations of preparation and technologies of production of the catalysts of reforming of gasoline fractions: Development of the process technology

The article summarizes the results of development of the scientific foundations of preparation of the catalysts, and of the experimental development works on creation of the new technologies of their production with the use of physical models, which were previously created on the basis of fundamental research. The results of the adoption of the new production technologies of the reforming catalysts of the PR series at the domestic plants are presented. The adoption consisted in creation and approbation of the fundamentally new technologies of production of the aluminum hydroxide (AHO) by means of the continuous method, modification of AHO by the elements of IV group, plasticization and forming of AHO in the production of the support, application of H₂PtCl₆ using the reactions of the ligand substitution of C⁻ by the functional groups of the support, and reduction and activation of the catalyst, which provide the optimal chemical com- position. Their operation during the 15-year period is analyzed. The reasons of high selectivity (up to 90%) of the new catalysts are found; the new technologies of the combined processing of mixture of C₃-C₄ alkanes with C₅₊ are developed and tested for the production of the high-octane catalysts with selectivity approaching 100%. The main effect of the C₅₊ yield increase of the end products is achieved by the transformation of the C₃-C₄ alkanes into the more high-molecular aromatic hydrocarbons. New processes of the combined processing of the mixtures of C₃-C₄ and gasoline fractions can be considered to be an alternative technology, which solves the important task of broadening the source of raw materials of the motor fuels by the inclusion of the C₃-C₄ alkanes of little value into the processing.     

Application of thermogravimetric analysis to study the thermal degradation of solid and liquid organic wastes

In this work, the thermolysis of composite binary mixtures of refinery or coal-processing waste with waste biomass and D-grade (long-flame) coal was analyzed in order to increase the efficiency of the cothermolysis of chemically different organic wastes mainly because of the synergism of the thermolysis of mixture components and, correspondingly, the selectivity of formation of high-quality by-products (solid, gaseous, or liquid). A new approach to the analysis of thermogravimetric data was proposed and developed as applied to complex binary mixtures of carbon-containing materials. This approach was based on (1) the preliminary separation of the thermal degradation of individual carbon-containing mixture components into individual structural constituents and (2) the monitoring of the conversion of each particular structure fragment as a constituent of the mixtures in the course of the cothermolysis of the mixtures of starting components. Based on the approach developed, data on the main synergism effects in the course of cothermolysis in the binary test systems were obtained: the temperature regions of the appearance of these effects were distinguished, the main conclusions were made with respect to particular structure fragments in complex organic wastes responsible for the interaction of components in composite systems, and the directions (positive or negative) of changes in the yields of solid by-products and the degrees of effects (difference between the yields of cothermolysis by-products in each particular region of the appearance of synergistic effects in the systems) were determined. Additionally, the influence of alkali metal carbonate additives on synergistic effects in the interaction between binary system components under the process conditions of cothermolysis was analyzed.     

桩-桩帽-系梁复合结构加固路基特性研究

高强预应力混凝土管桩(PHC管桩)加固深厚软土地基时,桩帽偏心会降低桩承式路基的整体加固效果,影响路堤稳定性。本文以某高速公路桩承式路堤工程为依托,利用有限元软件ABAQUS建立桩承式路堤三维数值模型,研究了桩帽向路基外侧不同偏心距对路堤边坡稳定性的影响,并提出桩-桩帽-系梁复合结构改进措施。研究结果表明:桩帽偏心时桩体荷载分担降低,地基沉降和侧向位移显著增大,桩土差异沉降增大,边坡稳定性降低,桩帽极限偏心距离为10cm;桩帽用系梁相连后,地基土沉降和差异沉降均明显减小,边坡稳定性提高,桩-桩帽-系梁复合结构改进措施有效。     

Effect of a change in the temperature of the drying agent on the heat treatment of a material

The process of heat and substance transfer between phases in drying a material is considered and ways to in tensify the internal transfer are indicated. The nature of the dependence of the temperature of the drying agent and the moist material at various points chosen for calculation on the technological parameters of the process is discussed. The method gives the effect of the independent variables of the process on the temperature of the used-up drying agent and the moisture content of the moist material. A control system that allows for a change in the energy stored by the lining of the furnace and the gas duct for automatic optimum adjustment of the regulator of the temperature of the drying agent is described.     

Effect of the addition of aramid-CTBN block copolymer on adhesive properties of cured epoxy resins modified with CTBN

To improve the bond strength of carboxy-terminated butadiene acrylonitrile (CTBN)-modified epoxy resin, aramid-CTBN block copolymer was used as an additive to a bisphenol-A-type epoxy resin modified with CTBN. With the addition of aramid-CTBN block copolymer, the fracture energy values of the adhesive joints were more than twice that of the CTBN-modified system and about twelve times that of the unmodified system. Observations of the adhesive layers using an optical microscope revealed that the width of the damage zone near the crack-tip in the double cantilever specimen increased with the addition of the aramid-CTBN block copolymer. TEM micrographs showed that the diameter of the CTBN-dispersed phases decreased and a number of fine CTBN phases were dispersed in the epoxy matrix with the addition of the block copolymer. It is concluded that addition of the block copolymer leads to an increase in the dispersibility of the CTBN elastomer into the epoxy matrix and thus the bond strength of the block copolymer-added system is increased due to the increase in the area of the damage zone and the occurrence of shear deformation of the epoxy matrix.     

Principles for Hydrodynamical and Geometrical Design of Vibrated Bed Driers

Processing in vibrated beds is characterized by the versatility and the easy controlability through parameters of vibration (amplitude, frequency and intensity). The main task of the control of processing is the synchronization of the residence time of particles in the processing area with the duration of drying. The drying time depends on the physical properties of the processed material, on the thermal parameters of the bed and on the operational parameters. The residence time depends on the mechanical properties of the particles, on the intensity of transport and on the eometrical parameters of the equipment. Since most of the parameters of the vibrational processing depend on the intensity of vibration, synchronization of the drying time with the residence time of particles, optimization of the process and optimal design of the vibrational equipment in general must be performed by the control of this operational parameter. Therefore a sophisticated algorithm and software for optimal control and design of vibrational processing equipment is needed. Such an algorithm based on the "Classification Scheme of Vibrated Systems" is described in this paper. The design algorithm has been tested using experimental data measured in a laboratory scale aerovibrofluidized bed dryer.