炭基固体酸催化废油脂合成生物柴油动力学研究(英文)

The kinetics of simultaneous transesterification and esterification with a carbon-based solid acid catalyst was studied.Two solid acid catalysts were prepared by the sulfonation of carbonized vegetable oil asphalt and petroleum asphalt.These catalysts were characterized on the basis of elemental analysis,acidity site concentration,the Brunauer-Emmett-Teller(BET)surface area and pore size.The kinetic parameters with the two catalysts were determined,and the reaction system can be described as a pseudo homogeneous catalyzed reaction.All the forward and reverse reactions follow second order kinetics.The calculated concentration values from the kinetic equations are in good agreement with experimental values.     

Prediction of curved oil–water interface in horizontal pipes using modified model with dynamic contact angle

In this study, interface shapes of horizontal oil–water two-phase flow are predicted by using Young-Laplace equation model and minimum energy model. Meanwhile, the interface shapes of horizontal oil–water twophase flow in a 20 mm inner diameter pipe are measured by a novel conductance parallel-wire array probe(CPAP). It is found that, for flow conditions with low water holdup, there is a large deviation between the model-predicted interface shape and the experimentally measured one. Since the variation of pipe wetting characteristics in the process of fluid flow can lead to the changes of the contact angle between the fluid and the pipe wall, the models mentioned above are modified by considering dynamic contact angle. The results indicate that the interface shapes predicted by the modified models present a good consistence with the ones measured by CPAP.     

空气与水逆流直接接触热质交换过程模型计算及分析

Based on reasonable model hypotheses and the energy analysis of heat and mass transfer of air and water in a direct contact counter flow, a set of general equations that can describe the internal relationship between the state parameters of air and water and dimensionless parameters of transfer process are given. A method utilizing MATLAB to solve these general equations is also proposed. Calculations and analysis with the model of a cooling- dehumidifying process give a consistent result with that of previous experiment. A new method for designing equipment such as evaporating cooler and cooling tower, and for analyzing experiment data of heat and mass transfer of air and water in a direct contact counter flow can be derived from this study.     

铜表面超疏水界面的构建与调控(英文)

Super hydrophobic copper wafer was prepared by means of solution immersion and surface self-assembly methods. Different immersion conditions were explored for the best hydrophobic surface. Scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and water contact angle measurements were used to investigate the morphologies, microstructures, chemical compositions and hydrophobicity of the produced films on copper substrates, respectively. Results show that the super hydrophobic surface is composed of micro structure of Cu 7 S 4 . The films present a high water contact angle larger than 150°, a low sliding angle less than 3°, good abrasion resistance and storage stability. The molecular dynamics simulation confirms that N-dodecyl mercaptan molecules link up with Cu 7 S 4 admirably, compared with Cu, which contributes to the stable super hydrophobic surface.     

Mass transfer performance of structured packings in a CO2 absorption tower

This paper studies the mass transfer performance of structured packings in the absorption of CO2 from air with aqueous NaOH solution. The Eight structured packings tested are sheet metal ones with corrugations of different geometry parameters. Effective mass transfer area and overall gas phase mass transfer coefficient have been measured in an absorption column of 200 mm diameter under the conditions of gas F-factor in 0.38–1.52 Pa0.5 and aqueous NaOH solution concentration of 0.10–0.15 kmol·m?3. The effects of gas/liquid phase flow rates and packing geometry parameters are also investigated. The results show that the effective mass transfer area changes not only with packing geometry parameters and liquid load, but also with gas F-factor. A new effective mass transfer area correlation on the gas F-factor and the liquid load was proposed, which is found to fit experiment data very well.     

Removal of diclofenac from aqueous solution with multi-walled carbon nanotubes modified by nitric acid☆

Modified multi-walled carbon nanotubes (MWCNTs) were used as adsorbents for removal of diclofenac. The re-action conditions were examined. Langmuir, Freundlich, Temkin, and Dubinin–Radushkevich isotherm models were applied to determine appropriate equilibrium expression. The results show that the experimental data fit the Freundlich equation well. Thermodynamic parameters show that the adsorption process is spontaneous and exothermic. The kinetic study indicates that the adsorption of diclofenac can be well described with the pseudo-second-order kinetic model and the process is controlled by multiple steps.     

An Improved Three-Dimensional Non-Equilibrium Mixing Pool Model

This paper presents an improved three-dimensional non-equilibrium mixing pool model.It is a simplified form of the original model and is more practical for applications.The simulation re-sults show that the industrial scale distillation tray columns can be described closely by the improvedmodel.The effects of model parameters,such as the number of mixing pools,the point efficiencyand flow pattern,on separation are analyzed quantitatively.     

AB-8树脂吸附反式1,2环己二醇热力学和动力学(英文)

AB-8 resin was used as an adsorbent for the removal of trans-1,2-cyclohexandiol(CHD) from aqueous solutions.Batch experiments were carried out to investigate the effect of contact time and temperature on sorption efficiency.The adsorptive thermodynamic properties and kinetics of CHD from water onto AB-8 resin were studied.The Langmuir and Freundlich isotherm models were employed to discuss the adsorption behavior.Thermodynamic parameters such as G,H and S were calculated.The results indicate that the equilibrium data are perfectly represented by Langmuir isotherm model.Thermodynamic study reveals that it is an exothermic process in nature and mainly physical adsorption enhanced by chemisorption with a decrease of entropy process.The kinetics of CHD adsorption is well described by the pseudo second-order model.The adsorbed CHD can be eluted from AB-8 resin by 5% ethanol aqueous solution with 100% elution percentage.     

高速滚动子午线轮胎变形和接地印痕预测方法

In this research，the tire deformations due to rotation are divided into three parts：tread，belt and carcass.Tread deformation is obtained by using a rotating hollow cylinder model，belt expansion is calculated according to the laminated composite shell theory，and a formula of dynamic equilibrium profile is built to investigate carcass deformation.Moreover，a simple method is used to predict the footprint changes caused by tire deformation.Results show that a large deformation is occurring at tire shoulder，a smaller one at tread centre，and the shoulder deformations are mostly caused by carcass.Length of footprint side edges increases with tire rolling speed increasing.The predicted tread，belt，carcass deformations and footprint changes are in good agreement with finite element analysis（FEA） results.The proposed method and the results will offer a helpful guidance to tire and vehicle engineers.     

废轮胎二氧化碳活化借助析因设计的系统分析(英文)

In this study,waste tire was used as raw material for the production of activated carbons through pyrolysis.Tire char was first produced by carbonization at 550℃ under nitrogen.A two factorial design was used to optimize the production of activated carbon from tire char.The effects of several factors controlling the activation process,such as temperature(850-950 ℃),time(2-6 h) and percentage of carbon dioxide(70%-100%) were investigated.The production was described mathematically as a function of these three factors.First order modeling equations were developed for surface area,yield and mesopore volume.It was concluded that the yield,BET surface area and mesopore volume of activated carbon were most sensitive to activation temperature and time while percentage of carbon dioxide in the activation gas was a less significant factor.     

载重子午线轮胎接地特性的有限元分析

采用Abaqus有限元分析软件建立11.00R20载重子午线轮胎与地面接触的三维有限元模型,研究轮胎的接地特性。结果表明:充气压力越高,轮胎接地区域应力出现中心低、边缘高翘曲现象的负荷值越大;下沉量增大,轮胎接地印痕从椭圆变为矩形,高压区由胎冠处移动到胎肩处;在各种工况中,轮胎静态接地面积最大;自由滚动时随着速度提高,轮胎接地印痕纵轴变长、横轴变短,但是接地面积增大,总接地反力也增大;摩擦因数对轮胎的自由滚动半径影响较小,但摩擦因数越大,纵向剪切应力越大,胎面越容易磨损;随着侧偏角增大,接地高压区逐渐向一边移动,接地印痕变为三角形。     

滚动轮胎侧倾侧偏接地性能有限元分析

建立了子午线轮胎滚动分析的三维有限元模型,在模型中充分考虑到轮胎材料和结构的复杂性,轮胎与轮辋过盈配合以及轮胎与轮辋、地面的摩擦等状况,研究了轮胎左侧倾、侧偏滚动状态下的变形情况、帘线的应力分析、接地区应力分布规律以及带束层帘线排列角度和侧倾角度对轮胎接地性能的影响,侧倾与侧偏的联合作用改善了接地区应力分布的不均匀性,不仅可以提高轮胎接地性能,而且使轮胎在纯侧倾状态下的偏磨得以缓解,体现了侧倾和侧偏的相互补偿作用.     

免充气轮胎与子午线轮胎有限元分析对比*

通过ABAQUS建立特殊结构的免充气轮胎有限元模型,对其静态加载和侧倾工况下进行了模拟,并将计算结果与同规格11.00R20载重子午线轮胎的实测数据作对比分析。研究表明：静载工况下,两者的静刚度曲线基本吻合,下沉量和接地面积接近,免充气胎最大接地压力较小;侧倾工况下,两者的接地面积和静刚度曲线的变化趋势接近。表明该免充气轮胎可以达到同规格子午线轮胎的性能要求。     

子午线轮胎负荷性能试验研究

对子午线轮胎195／60R14进行了试验研究。采用连续加载、卸载方式，开展了轮胎准静态负荷性能试验，同时还进行了轮胎静负荷性能试验。实时记录了试验中轮胎受力与变形关系，并采用压力敏感膜测量了轮胎在垂直状态及侧倾状态接地区域内的压力分布状况。给出了在准静态及静态负荷作用下轮胎与地面接触过程中轮胎的变形情况、接地面积、接触压力分布、载荷-变形关系等结果，     

轮胎特性对载重汽车性能的影响

研究轮胎滚动阻力、静态转向力矩和侧偏特性等因素对载重汽车性能的影响.结果表明,滚动阻力是载重汽车行驶阻力的主要部分;汽车动力转向系统匹配时应充分考虑轮胎的静态转向力矩,它随轮胎尺寸的增大而增大;轮胎特性不能用于调整汽车的稳态转向特性,横向稳定杆主要用于调整前后轴处的侧倾角.     

轮胎接触问题的分析与研究

简要地综述了轮胎接触问题分析的发展过程及所使用的一些方法，着重介绍了三维有限元法在轮胎接触问题中的应用，同时也概括了弹性力学理论及实验测试在轮胎接触问题中的应用。本文对轮胎接触问题的分析主要是围绕静态接触和滚动接触两方面展开论述的，列出了轮胎接触问题中轮胎变形、接触区形状大小、接触压力分布、应力分布、载荷变形关系、内轮廓形状等结果     

滚动轮胎耐久性有限元分析

为了研究子午线轮胎耐久试验后的破坏规律，建立了滚动轮胎三维非线性有限元模型。在模型中考虑了轮胎的几何非线性、材料非线性以及轮胎接触非线性，计算了滚动速度和侧倾角度对子午线轮胎195／60R14的变形及应变能密度分布的影响，并对影响轮胎耐久性的脱层现象进行了分析，从而可为提高轮胎耐久性能提供理论依据。     

侧倾滚动轮胎带束层受力状态有限元分析

建立了子午线轮胎滚动分析的三维有限元模型,在模型中充分考虑到轮胎材料和结构的复杂性,轮胎与轮辋过盈配合以及轮胎与轮辋、地面的摩擦等状况,研究了轮胎侧倾滚动状态下的变形情况以及侧倾角度对带束层应力分布的影响。     

435/50R19.5全钢载重子午线轮胎钢丝帘线受力分析

以435/50R19.5全钢载重子午线轮胎为例,采用有限元方法分析轮胎在充气、静负荷、侧倾、侧偏和驱动工况下带束层和胎体钢丝帘线的受力状况.结果表明,在充气和静负荷工况下,带束层和胎体钢丝帘线受力对称,在侧倾、侧偏及驱动工况下受力不对称;在各种工况下胎体钢丝帘线受力曲线形态差异较小,而带束层钢丝帘线差异较大.     

胎面花纹对轮胎性能影响的仿真研究

以ABAQUS有限元软件为平台,建立光面轮胎、周向沟槽轮胎和花纹轮胎的三维有限元模型,分析3种轮胎不同工况下的应力分布。结果表明:静负荷下3种轮胎等效应力分布基本相同,带束层端部受力最大,花纹轮胎整体应力水平最高,光面轮胎最低,但光面轮胎第1带束层应力较高;在静负荷、稳态滚动和侧偏滚动状态下,光面轮胎高应力区均在胎肩部位,而周向沟槽轮胎和花纹轮胎在静负荷和稳态滚动状态下高应力区主要分布在胎肩和胎面中心部位,侧偏滚动状态下在中心沟槽的边缘。