Evaluating the commercial airliner cabin environment with different air distribution systems

Ventilation systems for commercial airliner cabins are important in reducing contaminant transport and maintaining thermal comfort. To evaluate the performance of a personalized displacement ventilation system, a conventional displacement ventilation system, and a mixing ventilation system, this study first used the Wells‐Riley equation integrated with CFD to obtain the SARS quanta value based on a specific SARS outbreak on a flight. This investigation then compared the three ventilation systems in a seven‐row section of a fully occupied, economy‐class cabin in Boeing 737 and Boeing 767 airplanes. The SARS quanta generation rate obtained for the index patient could be used in future studies. For all the assumed source locations, the passengers’ infection risk by air in the two planes was the highest with the mixing ventilation system, while the conventional displacement ventilation system produced the lowest risk. The personalized ventilation system performed the best in maintaining cabin thermal comfort and can also reduce the infection risk. This system is recommended for airplane cabins.     

Homogeneous dispersion of boron nitride nanoplatelets in powder feedstocks for plasma spraying

Hexagonal Boron nitride nanoplatelet (BNNP) with the combination of excellent mechanical properties, high-temperature thermal stability, and self-lubrication is a promising strengthening agent in plasma-sprayed composite coatings. However, it is a significant challenge to produce plasma sprayable feedstocks with homogeneously dispersed BNNPs owing to the intrinsic agglomeration of BNNPs. In this research, three powder preparation processes (electrostatic interaction, ball milling, and shear mixing) were employed to disperse BNNPs in Ni-Cr-Cr₂O₃ (NCCO) powders. The shear mixing process presents a competitive advantage in powder preparation, providing stable shear force and achieving exfoliated BNNPs homogeneous distribution in the composite powders. The spray drying technique was finally utilized to obtain spherical agglomerated BNNP-NCCO feedstocks with characteristics of relatively smooth surface and uniform size distribution. Hence, shear mixing and spray drying processes are expected to produce large-scale spherical composite powders with a homogeneous distribution of 2D layered nanomaterials for industrial application.     

高抛免振自密实混凝土施工技术的应用

通过对某新建火车站局部站台高抛免振自密实混凝土方案的介绍,制定了该方案的施工工艺流程,并对其施工方法及施工质量控制措施作了阐述,说明了高抛免振自密实混凝土施工技术是一项能满足复杂构件混凝土浇筑要求,且技术可靠,操作简便,成本低的先进的混凝土施工新技术。     

Molecular dynamics simulations and thermodynamic modeling of NaCl–KCl–ZnCl2 ternary system

The NaCl–KCl–ZnCl₂ ternary system is examined and modeled using the CALPHAD methodology in conjunction with molecular dynamics (MD) simulations. In particular, MD simulations are used for calculating liquid enthalpies of mixing as a function of composition for the ternary and its binary sub-systems. In addition, key structural features are obtained from MD that is then used for informing the employed two-sublattice ionic liquid model (Na⁺¹, K⁺¹: Cl⁻¹, ZnCl₂), which describes the ternary liquid phase. The structure of the simulated liquid systems show that Zn⁺² cations primarily exhibit 4-fold coordination in addition to a smaller percentage of 5-fold followed by 3-fold coordination; in contrast, the coordination of both Na+ and K+ cations are distributed between 2- and 4-fold states. The optimized self-consistent thermodynamic model parameters show good agreement with MD data obtained in this work and available experimental literature data.     

An experimental analysis on the evolution of the transient tip penetration in reacting Diesel sprays

Schlieren imaging has helped deeply characterize the behavior of Diesel spray when injected into an oxygen-free ambient. However, when considering the transient penetration of the reacting spray after autoignition, i.e. the Diesel flame, few studies have been found in literature. Differences among optical setups as well as among experimental conditions have not allowed clear conclusions to be drawn on this issue. Furthermore, soot radiation may have a strong effect on the image quality, which cannot be neglected.     

Mixing of low-dose cohesive drug and overcoming of pre-blending step using a new gentle-wing high-shear mixer granulator

The objective of this study was to examine the influence of drug amount and mixing time on the homogeneity and content uniformity of a low-dose drug formulation during the dry mixing step using a new gentle-wing high-shear mixer. Moreover, the study investigated the influence of drug incorporation mode on the content uniformity of tablets manufactured by different methods. Albuterol sulfate was selected as a model drug and was blended with the other excipients at two different levels, 1% w/w and 5% w/w at impeller speed of 300?rpm and chopper speed of 3000?rpm for 30?min. Utilizing a 1?ml unit side-sampling thief probe, triplicate samples were taken from nine different positions in the mixer bowl at selected time points. Two methods were used for manufacturing of tablets, direct compression and wet granulation. The produced tablets were sampled at the beginning, middle, and end of the compression cycle. An analysis of variance analysis indicated the significant effect (p?mixing of low-dose cohesive drug and provides tablets with acceptable content uniformity with no need for pre-blending step.     

Interactions of mixing and reaction kinetics of depolymerization of cellulose to renewable fuels

As the biofuel industry is heavily depend on technological advancement to remain competent, creation of new process techniques becomes inevitable to replace the existing under-performed operations. Mixing in the reactor requires enormous amount of energy to achieve required homogeneity. Reduction in the energy consumption and ultimately the cost of the product is possible by devising smart mixing strategies. In this review, interactions of mixing and reaction kinetics of enzymatic hydrolysis, fermentation, and cellulosic depolymerization in ionic solvents are discussed. When the processes are operated under various mixing conditions, changes in the reaction kinetics and dynamics of the processes occur. Therefore, analyzing the mixing effects at various levels (micro to macro) is crucial to decide best operating mixing conditions that drive the reaction kinetics toward the increased product yield. The review is helpful to identify a suitable mixing strategy that maximizes the production of biofuels—ethanol, 5-hydroxymethylfurfural, etc.     

Evaluation of iron–epoxy metal nanocomposite in glass fibre and Kevlar

This paper deals with the enrichment of the both mechanical and electrical properties of Kevlar and glass fibres, not including mounting the weight of the structure by adding the iron (Fe) nanocomposites with the epoxy resin. The Fe is mixed well with the epoxy to increase the mechanical constancy and the electrical property of the fibre by a non-covalent approach. The synthesis of metal nanocomposite with epoxy is done by the direct mixing method. The Kevlar and the glass fibre were taken as the samples for this study. The zinc oxide and epoxy were mixed simultaneously using a mechanical stirrer to give appropriate dispersion and adhesion without disturbing the hydrophobic performance of the epoxy, and the Fe powder and epoxy are added with a hardener in the ratio of 1:1:0.1. The results show that the mechanical property of the fibre increased with the decrease in the weight of the laminate when they are treated with the metal nanocomposite.     

Phase equilibria calculation of LaI3-MI （M=Na, K, Cs） binary systems

The Gibbs energies of liquid phases in the LaI3-MI (M=Na, K, Cs) systems were described by the modified quasi-chemical model. From the measured phase equilibrium data of these binary systems, a set of thermodynamic functions were optimized by using the CAL-PHAD technique. The enthalpy of mixing and the interaction parameter of the liquid phase were predicted from known data for the LaI3-MI systems.     

集中供暖换热站扩容供热方式的选择

通过对某换热站新增区域的供热方式与原采暖用户进行系统分析,建议新增区采用间接连接和混水直接连接两种方案,并对两种方案给出详细的设计说明;通过对两种方案进行整体比较分析,综合得出混水直供换热方式运行经济,供热效果良好,尤其是区域供热新增区或新建区采暖用户的供热选择方式。