Gluten–starch interface characteristics and wheat dough rheology—Insights from hybrid artificial systems

Referring to the total surface existing in wheat dough, gluten–starch interfaces are a major component. However, their impact on dough rheology is largely unclear. Common viewpoints, based on starch surface modifications or reconstitution experiments, failed to show unambiguous relations of interface characteristics and dough rheology. Observing hybrid artificial dough systems with defined particle surface functionalization gives a new perspective. Since surface functionalization standardizes particle–polymer interfaces, the impact on rheology becomes clearly transferable and thus, contributes to a better understanding of gluten–starch interfaces. Based on this perspective, the effect of particle/starch surface functionality is discussed in relation to the rheological properties of natural wheat dough and modified gluten–starch systems. A competitive relation of starch and gluten for intermolecular interactions with the network-forming polymer becomes apparent during network development by adsorption phenomena. This gluten–starch adhesiveness delays the beginning of non-linearity under large deformations, thus contributing to a high deformability of dough. Consequently, starch surface functionality affects the mechanical properties, starting from network formation and ending with the thermal fixation of structure.     

Optimal operating conditions to maximize the net power of polymer electrolyte membrane fuel cells: The stack-system interface of a commercial 18 kW module

A new, experimental method based on air flow rate rather than current is presented to optimize operating parameters for the stacks and systems of proton exchange membrane fuel cells (PEMFCs) for maximizing their net power. This approach is illustrated for a commercial 18 kW PEMFC module. The impact of contamination pressure drop across the cathode air filter is also investigated on the compressor behavior. It is further shown that a 4V reduction in the compressor voltage reduces its power consumption by 9.1%. Using the 3D graphs of the power-pressure-flow data, it is found that the stack pressure of 180 kPaa is superior to the higher tested pressures as it enhances the net power by 7.0 and 13.7% at different conditions. Application of the present study will lead to the development of PEMFCs with higher power output by optimizing stack pressure, stoichiometry and air flow to properly deliver the system design specifications.     

基于可供性的文化意象交互式智能音箱设计研究

目的 探索将文化民俗有效融入现代产品中的技术思路，保留并延续中华传统文化的生命力，有助于提升用户体验。方法 分析可供性与文化意象之间的主客观互通性;挖掘交互式智能音箱中的可供性触点;构建形态、感官、认知及情境四类可供性的设计框架;以楚文化意象为例进行设计实践，对智能音箱的产品造型与交互操作方式进行设计，并进行设计评价。结果 在可供性理论指导下的楚文化意象交互式智能音箱产品外观及交互体验设计较好地满足了设计目标和用户需求。结论 可供性有助于文化意象的正确提取与转化，可将意象抽象为具有实际意义的设计要素，帮助用户在生理与认知两个层面理解产品的使用方法，同时进一步回味、体验文化内涵和文化精髓。     

异种铁素体耐热钢接头界面组织及其影响

综述了铁素体与铁素体异种金属焊缝（dissimilar metal welds，DMWs）接头界面组织及其影响。结果表明，在焊后热处理或运行温度下的铁素体钢DMWs接头的不均匀界面组织中，通常会形成脱碳层和增碳层。在铁素体钢DMWs焊接接头界面组织影响因素中，焊缝金属的化学成分有重要影响；焊后热处理规范（温度和时间）、工作温度下运行时间的影响较为突出；焊接工艺参数的影响亦不可忽略。异种钢接头界面处近缝区裂纹的产生，以及接头的蠕变强度随Larson Miller 参数增大而下降等不利影响，均为异种钢界面碳迁移行为所导致。焊缝成分控制法是接头界面组织控制或改善的必要条件，而脱碳层部位转移法能有效防止裂纹发生，亦是接头安全运行的重要工艺措施之一。     

高压水射流对白云鄂博矿单体解离度的影响

矿物的单体解离是其能被高效选别的关键因素之一，粉碎方法对矿物单体解离度有很大的影响。白云鄂博稀土矿含十几种稀土矿物，矿物共生密切，嵌布类型复杂，其中稀土主要富集在氟碳铈矿与独居石矿中。分析表明矿物因相互包裹穿插和交代而形成毗连、网脉、溶蚀和环状嵌布。为提高矿物的单体解离度，通过自主研发水射流矿物解离装置，探究了水射流速度对白云鄂博矿稀土单体解离度的影响。在同等粒度分布下，对高压水射流粉碎与常规球磨(铁介质)实验结果进行了对比，分析了两种粉碎方式对稀土矿物解离状态及颗粒界面的影响。激光共聚焦显微镜、矿物特征自动定量分析系统(AMICS)分析表明，高压水射流粉碎白云鄂博稀土矿物单体解离度优于球磨，具有解离度高、粒度相对均匀等特点；矿物颗粒天然界面保持较好、表面较光洁，稀土矿物集中在0.038 mm以下颗粒中，有益于稀土的浮选分离，对白云鄂博矿的矿石粉碎具有一定的指导意义。     

射流卷吸边界层内相干结构的实验研究

在轴对称水射流实验台上，采用单帧长曝光图像法，测量了出口Reynolds数在1849~2509范围内的卷吸边界层内流场结构。发现在流向距离L=2D~3.5D，径向距离H=D~1.25D的区域内，流场中吞噬作用和侵蚀作用两种卷吸模式交替出现。分析得到，当Re>1915时，吞噬作用所占的比例随着Re的增大而增大，当Re>2311之后，Reynolds数对该结构发生概率的影响降低；通过快速傅里叶变换得到该相干结构发生的频率在10～19Hz之间；吞噬作用发生的同时在流场中观测到一些特殊涡结构。同时采用运动单帧长曝光图像法对射流流场进行拉格朗日法观测，发现射流流场中的涡结构一般存在于湍流与非湍流界面附近。     

环烷基NiFe2O4磁流体的制备及有磁场沉降稳定性

目前，磁流体的制备方法多为化学共沉淀法，关于磁流体微乳化制备工艺及有磁场沉降稳定性的研究较少。采用单因素和均匀实验设计方法，判定分散剂及其质量分数对环烷基NiFe₂O₄磁流体沉降稳定性的影响。本文采用微乳化法制备环烷基NiFe₂O₄磁流体，通过样品沉降系数和黏度特性，研究分散剂种类与其质量分数、NiFe₂O₄纳米磁性颗粒质量分数、乳化剂种类及温度对磁流体有磁场沉降稳定性的影响，得到制备环烷基NiFe₂O₄磁流体的较佳参数值。研究结果表明：当十二烷基苯磺酸钠（SDBS）、十二烷基硫酸钠（SDS）与油酸（OA）的质量分数在1%～6%范围内，环烷基NiFe₂O₄磁流体的沉降稳定性较好，并且SDBS与OA的含量对其稳定性的影响大于SDS；当分散剂定量时，随着NiFe₂O₄纳米磁性颗粒质量分数的增加，磁流体先表现出较好的稳定性，后逐渐出现团聚；在一定温度时，乳化剂Surf CA20有利于磁流体内部形成液晶相，减小液珠间吸引势能并且降低磁性颗粒的聚结速度，提高磁流体的有磁场沉降稳定性。     

Interface-based crystal particle autoselection via membrane crystallization: From scaling to process control

Accurate crystallization control is an essential aspect for chemical engineering and separation processes. Herein, we demonstrated the novelty of membrane crystallization (MCr) on the interfacial based-crystal particle autoselection aimed for nucleation regulation and process control. With the proposed model based on a van der Waals-friction-hydrodynamic force field and classical nucleation theory, the motion mechanisms of heterogeneously induced nucleation were illustrated. The defined particle detachment criterion K revealed the control mechanism of the crystal particle motion behavior: temporary adherence, detachment, and perpetual adherence (scaling) at the membrane interface. For the first time, the function region of MCr (nucleation detection, scaling control, and crystallization regulation) was systematically illustrated and validated with the directly observed laboratory demonstration. These findings also demonstrate the potential applications of the uniform size distribution, morphology modified particle manufacture, and in situ nucleation detection. © 2018 American Institute of Chemical Engineers AIChE J, 65: 723–733, 2019     

Ordinary Gasoline Emissions Induce a Toxic Response in Bronchial Cells Grown at Air-Liquid Interface

Gasoline engine emissions have been classified as possibly carcinogenic to humans and represent a significant health risk. In this study, we used MucilAir™, a three-dimensional (3D) model of the human airway, and BEAS-2B, cells originating from the human bronchial epithelium, grown at the air-liquid interface to assess the toxicity of ordinary gasoline exhaust produced by a direct injection spark ignition engine. The transepithelial electrical resistance (TEER), production of mucin, and lactate dehydrogenase (LDH) and adenylate kinase (AK) activities were analyzed after one day and five days of exposure. The induction of double-stranded DNA breaks was measured by the detection of histone H2AX phosphorylation. Next-generation sequencing was used to analyze the modulation of expression of the relevant 370 genes. The exposure to gasoline emissions affected the integrity, as well as LDH and AK leakage in the 3D model, particularly after longer exposure periods. Mucin production was mostly decreased with the exception of longer BEAS-2B treatment, for which a significant increase was detected. DNA damage was detected after five days of exposure in the 3D model, but not in BEAS-2B cells. The expression of CYP1A1 and GSTA3 was modulated in MucilAir™ tissues after 5 days of treatment. In BEAS-2B cells, the expression of 39 mRNAs was affected after short exposure, most of them were upregulated. The five days of exposure modulated the expression of 11 genes in this cell line. In conclusion, the ordinary gasoline emissions induced a toxic response in MucilAir™. In BEAS-2B cells, the biological response was less pronounced, mostly limited to gene expression changes.