Thermal Energy Accumulation during Passage of a Combustion Wave through a Wedge-Shaped Obstacle

Combustion, Explosion, and Shock Waves - A computational and experimental study of the passage of a gasless combustion wave through a wedge-shaped inert obstacle was performed. The stability of the...     

Passage of Trojan Peptoids into Plant Cells

Efficient drug delivery is essential for many therapeutic applications. In this context, Trojan peptoids have attracted attention as powerful tools to deliver bioactive molecules into living cells. Certain cell‐penetrating peptides, peptide mimetics, and peptoids have been shown to be endowed with a transport function and the structural features of this function have been characterized. However, most of the research has been done by using mammalian cell cultures as model organisms and the actual cellular mechanism of membrane passage has not been elucidated. Plant cells, which are encased in a cellulosic cell wall and differ in membrane composition, represent an alternative experimental system to address this issue, but so far, have attracted only little attention for both peptide‐ and peptoid‐based carrier systems. Moreover, efficient delivery of nonproteinaceous bioactive macromolecules into living plant cells could complement genetic engineering in biotechnological applications, such as metabolic engineering and molecular farming. In the present study, we investigated carrier peptoids with or without guanidinium side chains with regard to their uptake into plant cells, the cellular mechanism of uptake, and intracellular localization. We can show that in contrast to polyamine peptoids (polylysine‐like) fluorescently labeled polyguanidine peptoids (polyarginine‐like) enter rapidly into tobacco BY‐2 cells without affecting the viability of these cells. A quantitative comparison of this uptake with endocytosis of fluorescently labeled dextranes indicates that the main uptake of the guanidinium peptoids occurs between 30–60 min after the start of incubation and clearly precedes endocytosis. Dual visualization with the endosomal marker FM4‐64 shows that the intracellular guanidinium peptoid is distinct from endocytotic vesicles. Once the polyguanidine peptoids have entered the cell, they associate with actin filaments and microtubules. By pharmacological manipulation of the cytoskeleton we tested whether the association with the cytoskeleton is necessary for uptake, and observed that the actin inhibitor latrunculin B as well as the microtubule inhibitor oryzalin impaired uptake and intracellular spread of the guanidinium carrier to a certain extent. These findings are discussed with respect to the potential mechanisms of uptake and with respect to the potential of Trojan peptoids as tools for metabolic engineering in plant biotechnology.     

降液膜波动的影响因素分析

建立了溴化锂溶液沿平板降膜的流动模型。利用VOF方法捕捉降液膜的自由流动表面,利用CSF模型考虑表面张力对降液膜流动的作用,研究了入口扰动频率、降膜Re和平板倾斜角对降膜波动演化过程的影响。模拟结果表明,入口处的低频率扰动发展为孤波,随着频率的增加,波长减小,孤波与孤波通过他们之间的波后、衬底和毛细波相互影响,而高频率扰动演变成毛细波。随着Re的增加,波幅和波长增加,同时波峰处的循环流动强度增加。随着倾斜角的增加,重力沿流动方向的分力增加,波发展速度增加。同时分析了波内的速度场和壁面切应力等动力学特性。     

Liquid diffusion into epoxy resin composites

Dynamic sorption behavior of four epoxy resin matrix composites derived from fly ash, jute, mica, or vermiculite was studied in water and salt solution at 24°, 35°, and 45°C. The mass of water uptake per mass of sample was determined as a function of time. Diffusion coefficients were higher for distilled water than those for salt solution. The diffusion parameters were computed from the Arrhenius plots and the results analyzed in terms of a Fickian model. The results as obtained from weight gain assays are consistent with the view that the activation energy of diffusion is associated with the energy required to produce a space of sufficient cross-section for the diffusing molecule to pass.     

Analyzing Biomass Conversion into Liquid Hydrocarbons

Variants of the Fischer–Tropsch producer-gas conversion into liquid hydrocarbons are analyzed under the assumption that thermodynamic equilibrium is attained in the reactions occurring in the biomass gasification. When the raw material is wood waste, the optimum variant of the process involves partial biomass oxidation by atmospheric oxygen with tail-gas recycling after the separation of liquid hydrocarbons. Before mixing with fresh producer gas, the hydrocarbons contained in the tail gas are reformed on a nickel catalyst.     

Factors Affecting the Significance of Gravity on the Infiltration of a Liquid into a Porous Solid

A mathematical model is formulated to illustrate the significance of gravity on the infiltration of a liquid in a porous solid. The result indicates that the relative significance of gravity on the infiltration depth depends on the infiltration time as well as the properties of the permeating liquid and the porous solid. The effect of gravity can be neglected for a short infiltration time, and for infiltration systems with the infiltrating liquid having a large value of surface energy, a small value of wetting angle on the solid, and a low density, and the porous solid having a small equivalent capillary radius and a small tortuosity.     

Hydrodynamics and Heat Transfer in the Bubbling of Steam Entrained by Liquid Jets Falling through a Steam Medium and Plunging into a Liquid

The hydrodynamics and heat transfer are studied in a layer of subcooled water into which vertical liquid jets plunge from a steam medium above the liquid and entrain steam from the steam space. The studies are performed as applied to the operating conditions of direct-contact jet condensers and deaerators. An equation is obtained for calculating the heat transfer in the receiving layer in the case of complete condensation of steam entrained by jets.__________Translated from Teoreticheskie Osnovy Khimicheskoi Tekhnologii, Vol. 39, No. 4, 2005, pp. 362–372.Original Russian Text Copyright © 2005 by Trofimov.     

马丁-侯状态方程向液相发展

1955年发表的气体状态方程式经过改进后,其应用范围扩展到液相。在原方程中增加了一个常数,B_4,即: P=RT/(V-b)+(A_2+B_2T+C_2e~(-5.475Tr))/(V-b)~2+(A_3B_3T+C_3e~(-5.475Tr))+(A_4+B_4T)/(V-b)~4+(B_5T)/(V-b)~5并且使方程式满足一个条件,integral from n=V_1 to V_0(PdV)=P_0(V_0-V_1),就可以求出常数B_4的数值。 改进后的方程对一般物质,如二氧化碳、正丁烷、氩、甲烷及氮等,在对比温度Tr约从0.65到临界温度,计算的饱和液相的摩尔容积与文献数据比较,平均偏差不到5％。同时,气相的摩尔容积基本上保持原来的精确度（偏差在1％以内）。并且,不须要增加所需的数据。     

Liquid Phase Sintering of Alumina, II. Penetration of Liquid Phase into Model Microstructures

Alumina preforms containing artificial pores were sintered at 1630°C in air and vacuum. Glass penetration into the alumina preforms was conducted at 1600°C in air. It was found that the trapped gases in alumina preforms sintered in air caused the random and incomplete filling of the smaller and larger artificial pores. In contrast, the pores in the alumina preform sintered in vacuum were completely filled during glass penetration.     

Characteristics of Liquid Penetration into Undoped and Magnesia-Doped Alumina

Liquid-forming impurities (CaO + SiO₂) were placed on the top of undoped and MgO-doped Al₂O₃ powder compacts, and the microstructural evolution and the extent of liquid penetration during heat treatment were investigated. Compared with the undoped specimen, abnormal grain growth was limited and the impurities penetrated more deeply in the MgO-doped specimen. The homogenization of the microstructure and the enhanced liquid penetration in MgO-doped specimens could be explained in terms of an interface roughening or a modification of the liquid-(glass-) phase characteristics, such as viscosity.     

Exit of a Heterogeneous Detonation Wave into a Channel with Linear Expansion. II. Critical Propagation Condition

Propagation of a detonation wave in monodisperse suspensions of reacting particles (based on the model of the suspension of aluminum particles in oxygen) in channels with linear expansion is studied within the framework of mechanics of heterogeneous reacting media. Reduced kinetics is described with allowance for the transitional (from diffusion to kinetic) regime of combustion of micron-sized and submicron-sized spherical aluminum particles. The effects of the channel width, particle diameter, and expansion angle on propagation conditions and detonation regimes are determined. The critical channel width is found to be a nonmonotonic function of the expansion angle, which is associated with qualitatively different wave patterns behind an oblique step. Flow charts are constructed, and the results are compared with solutions of problems of heterogeneous detonation wave propagation in channels with a backward-facing step and with sudden expansion.     

Direct Transfer of Gas-Borne Nanoparticles into Liquid Suspensions by Means of a Wet Electrostatic Precipitator

The direct transfer of flame-synthesized aerosols of silica nanoparticles into aqueous suspensions is investigated. Silica nanoparticle aerosols with production rates of 0.5 g/h and different mean diameters and degrees of agglomeration are transferred into liquid suspensions by means of a novel wet electrostatic precipitator. Particle collection efficiencies above 99.999% were measured. The influence of the transfer on the particle size distribution was investigated by comparison of aerosol and suspensions size measurements. Aerosol sizes were measured with the scanning mobility particle sizer (SMPS), and suspension size measurements were conducted by dynamic light scattering (DLS) and by SMPS measurements of the aerosolized suspension employing a novel nebulizer. Depending on the aerosol and stabilization conditions, particle transfer with nearly no influence on the particle size distribution is possible. Suspensions generated from the same particle aerosol by direct transfer and by sonication of the respective powder were compared. In contrast to the direct transfer, the aerosol particle size distribution could not be restored by ultrasonication.

Copyright © 2015 American Association for Aerosol Research     

动力波湿式洗涤器的液体喷射高度及阻力损失的计算

通过理论分析及试验研究,得出了动力波湿式洗涤器的液体喷射高度及阻力损失的计算式,且计算值与实测值非常接近,为动力波湿式洗涤器的设计及放大提供可靠依据。     

超声波对氯代1-烯丙基-3-甲基咪唑离子液体合成的强化

采用超声波辅助加热回流的方法合成了氯代1–烯丙基–3–甲基咪唑离子液体([AMIM]Cl),并对其进行了紫外光谱(UV)和傅利叶红外光谱(FT–IR)表征。考察了反应物摩尔比、反应时间和超声波功率对离子液体的收率和纯度的影响,探讨了超声波对合成反应的强化效应。实验结果表明超声波能强化[AMIM]Cl的合成,明显缩短合成时间,且其强化效应受反应物摩尔比的影响较小,而与超声波功率紧密相关。[AMIM]Cl适宜的合成条件为反应温度50℃、反应时间2h、氯丙烯与1–甲基咪唑的摩尔比1.4、超声波功率100W,此时离子液体的收率和纯度分别为94.4%和99.2%。     

热粘液中引入挥发性冷剂进行汽化冷却的传热研究

研究了热粘液中引入挥发性冷剂进行汽化冷却的传热过程。在一垂直圆形循环管中,引入冷剂酒精液滴于热浓糖溶液中,获得了糖液的汽化冷却曲线：分析了冷剂通入量对瞬间主体温度及容积传热速率的影响,并以“界面汽化热阱”的概念对传热机理进行了分析。冷剂在热粘液中汽化,是以泡滴的形态进行的。由于酒精与糖液是互溶的,在圆形管中对于泡滴的形态以及酒精与浓糖溶液间的界面难以观察清楚,因而设计了一套便于观察、拍照和分析的由两块玻璃板组成的窄缝且外侧带有保温夹套的实验设备(类似于Hele．Shaw盒)。在该设备中,对不互溶冷剂及可互溶冷剂在热浓糖溶液中汽化时形成泡滴的状态进行了比较,并分析了它们具有不同状态的原因。     

Passage of SHS wave through a gap: Mathematical modeling

Stability of combustion wave during its passage through a gaseous gap between two reactive layers was studied by mathematical modeling. The character of transient processes in the gap was explored as a function of thermophysical parameters of the layers, kinetic parameters, and gap width at a predominant role of radiative heat transfer. The passage of combustion wave through the gap was found to be accompanied by the attainment of superadiabatic temperatures within the transition zone. A critical temperature for burning failure at the interface was determined.     

液态醇催化氧化制醛或酮的研究进展

对液态醇催化氧化制醛或酮按照均相催化、液固多相催化和有机相－水相两相催化、催化剂分金属类别进行了回顾，认为液固多相催化剂和有机相－水相两相催化有着诱人的发展前景。     

液体复混肥料生产技术初步探讨

我国发展液体肥料起步较晚,随着我国叶面喷施和喷滴灌技术的开发和应用,液体复混肥料得到迅速发展.为适应液体复混肥料的发展形势,对生产液体复混肥料种类、生产原料和生产工艺做了初步研究和简单探讨.