Separation of multicomponent aromatic/aliphatic mixtures by simulated moving bed adsorption: Modeling and experiments

Simulated moving bed (SMB) adsorption has potential for efficient separation of many valuable chemical mixtures, but considerably less attention has been devoted to multicomponent feeds relative to binary mixtures. We take a rigorous experimental and modeling approach to study multicomponent separation of aromatics and aliphatics with a mesoporous silica adsorbent, which is relevant in many petrochemical applications such as separation of reformate and distillate streams. Our approach involves refining multicomponent adsorption, mass transfer, and SMB process parameters based upon detailed experimental inputs, with progressive addition of components. We develop a robust model that quantitatively predicts the influence of key operating parameters such as stream flow rates, desorbent/feed ratio, and switch time on the separation results and concentration profiles. The model is validated as a function of feed complexity by SMB experiments and column concentration profile measurements in a 16-column mini-plant. Furthermore, conditions for clear separation of each mixture are developed.     

Design of a Mobile Robot Controller using Esterel Tools

Robot controllers are often programmed using either standard sequential programming languages or a robot-specific language, which are then compiled to assembly language specific to the robot. Modern real-time programming languages, on the other hand, are more appropriate to program robots, as they better fit the real-time reactive model of robots. This paper reports on a project to program a non-trivial robot, the Rug Warrior, in the Artificial Intelligence Laboratory of UNSW, using Esterel, which is a real-time programming language. The approach is illustrated by simulation of a colony of Siberian ants using a group of Rug Warriors.     

印度：新兴炼油中心

全球的炼化工业正经历着需求与供给不平衡的时期。在欧洲和北美这些发达地区,最近三十年来都没有出现过什么新的炼油厂,考虑到环境因素和公众反对,估计未来也不会有什么变化。而与此相反,印度现在的炼油能力已经接近每年1亿5千万吨（100万吨=733万桶），并且还在继续增加，预计到201年将达到每年2．1亿桶。国内需求的增长是这个国家正成为炼油中心的重要原因，同时印度正在快速弥补着国际市场上精炼产品的不足。     

Influence of fiber orientation on abrasive wear of unidirectionally reinforced carbon fiber–polyetherimide composites

A composite with continuous carbon fibers (CF) (80% by vol.) and high performance thermoplastic polyetherimide (PEI) matrix was developed and evaluated for various mechanical properties as a function of fiber orientation angle (0°, 30°, 45°, 60° and 90°). It was observed that Young's modulus, Poisson's ratio, toughness and % strain decreased with the increase of fiber orientation angle with respect to loading direction. In-plane shear modulus was highest for fibers with 45°. Overall, unidirectional (UD) CF reinforcement enhanced all strength properties of PEI significantly. Composites with fibers in 0° (parallel to loading direction) proved best in almost all the properties. Tribological evaluation in abrasive wear mode under different loads and fiber orientations indicated that coefficient of friction (μ) and specific wear rate (K₀) decreased with load, in general. Comparatively low specific wear rate (K₀), (in the order of 0.7 1×10^?9 m³/Nm) was observed for 0° fiber orientation, while fibers in 90° showed almost three times higher wear rate. Overall fiber reinforcement in 0° orientations proved beneficial from both strength and tribological performance point of view. SEM proved useful to correlate wear rate with surface topography.     

Analysis of a Chiral Dielectric Supported Broadband Helix Slow-Wave Structure for Millimeter-Wave TWTs

A novel technique of broadbanding a helical slow-wave structure through negative dispersion shaping is proposed. The model considers a simple continuous chiral dielectric support for the helix inside a metallic barrel, unlike conventional helix slow-wave structures with three discrete dielectric supports at 120⁰ apart. The dispersion relation of the slow-wave structure was derived following sheath-helix abstraction, suitably benchmarked for special cases, and was used for analyzing the dispersion behavior of a typical slow-wave structure. Chiral dielectric loading could easily provide negative dispersion characteristics (required for broadband operation) by merely controlling the chirality parameter alone. The scheme with its simple geometric configuration is expected to be useful for millimeter-wave devices providing better thermal management.     

Prolonged Exposure to Simulated Microgravity Changes Release of Small Extracellular Vesicle in Breast Cancer Cells

Breast cancer is the leading cause of cancer incidence worldwide and among the five leading causes of cancer mortality. Despite major improvements in early detection and new treatment approaches, the need for better outcomes and quality of life for patients is still high. Extracellular vesicles play an important role in tumor biology, as they are able to transfer information between cells of different origins and locations. Their potential value as biomarkers or for targeted tumor therapy is apparent. In this study, we analyzed the supernatants of MCF-7 breast cancer cells, which were harvested following 5 or 10 days of simulated microgravity on a Random Positioning Machine (RPM). The primary results showed a substantial increase in released vesicles following incubation under simulated microgravity at both time points. The distribution of subpopulations regarding their surface protein expression is also altered; the minimal changes between the time points hint at an early adaption. This is the first step in gaining further insight into the mechanisms of tumor progression, metastasis, the education of the tumor microenvironments, and preparation of the metastatic niche. Additionally, this may lighten up the processes of the rapid cellular adaptions in the organisms of space travelers during spaceflights.     

Influence of Plasma Treatment on Carbon Fabric for Enhancing Abrasive Wear Properties of Polyetherimide Composites

Interfacial adhesion between matrix and fiber plays a crucial role in controlling performance properties of composites. Carbon fibers have major constraint of chemical inertness and hence limited adhesion with the matrix. Surface treatment of fibers is the best solution of the problem. In this work, cold remote nitrogen oxygen plasma (CRNOP) was used for surface treatment. Twill weave carbon fabric (CF) (55–58 vol%) was used with and without plasma treatment with varying content of oxygen (0–1%) in nitrogen plasma to develop composites with Polyetherimide (PEI) matrix. The composites were developed by compression molding and assessed for mechanical and tribological (abrasive wear mode) properties. Improvement in tensile strength, flexural strength, and interlaminar shear strength (ILSS) was observed in composites due to treatment. Similarly, improvement in wear resistance (W _R) and reduction in friction coefficient (μ) were observed in treated fabric composites when slid against silicon carbide (SiC) abrasive paper under varying loads. A correlation between wear resistance and tensile strength was slightly better than that in Lancaster–Ratner plot indicating that ultimate tensile strength (S) and elongation to break (e) were contributing to control the W _R of the composites. It was concluded that enhanced adhesion of fibers with matrix was responsible for improvement in performance properties of composites, as evident from SEM, Fourier Transform Infrared spectroscopy-Attenuated Total Reflectance (FTIR-ATR) technique.     

Formation of Calcium Titanate During Electroreduction of TiO2 in Molten CaCl2 Bath

The direct electrochemical reduction of a TiO₂ cathode in a molten CaCl₂ bath to produce titanium metal invariably results in the formation of CaTiO₃ as an intermediate product. To obtain even more insight into the formation of CaTiO₃, experiments are performed in open-circuit conditions as well as at a cell voltage of 2?V for different time periods. In this study, we examine the conversion of TiO₂ to CaTiO₃ in the molten CaCl₂ bath. Prolonged electrolysis experiments are conducted and the newly transformed phases are analyzed using X-ray diffraction (XRD). The formation of CaTiO₃ and its subsequent transformation to different species during reduction is discussed. An approach for preparing CaTiO₃ chemically by treating the TiO₂ electrode in CaCl₂ bath and subsequently reducing it by electrochemical means to produce titanium metal has been proposed.