Optimal synthesis of refrigeration cycles and selection of refrigerants

The optimal synthesis of the refrigeration configuration and the selection of the best refrigerants that satisfy a set of process cooling duties at different temperatures is addressed. This approach simultaneously selects refrigerants and synthesizes refrigeration structures by minimizing a weighted sum of investment and operating costs. A superstructure representation considers the majority of refrigeration cycle features encountered in real complex multistage refrigeration cycles such as economizers, multiple refrigerants, and heat integration. A novel theoretical treatment of modeling representations and algorithmic improvements is introduced. Results, for example, involving multiple refrigerants, cooling loads, and heat sinks are obtained. Complex, nonintuitive topologies typically emerge as the optimal refrigeration configurations that are better than those obtained when refrigeration synthesis is performed after refrigerant selection.     

Super‐resolution Imaging of Amyloid Structures over Extended Times by Using Transient Binding of Single Thioflavin T Molecules

Oligomeric amyloid structures are crucial therapeutic targets in Alzheimer's and other amyloid diseases. However, these oligomers are too small to be resolved by standard light microscopy. We have developed a simple and versatile tool to image amyloid structures by using thioflavin T without the need for covalent labeling or immunostaining. The dynamic binding of single dye molecules generates photon bursts that are used for fluorophore localization on a nanometer scale. Thus, photobleaching cannot degrade image quality, allowing for extended observation times. Super‐resolution transient amyloid binding microscopy promises to directly image native amyloid by using standard probes and record amyloid dynamics over minutes to days. We imaged amyloid fibrils from multiple polypeptides, oligomeric, and fibrillar structures formed during different stages of amyloid‐β aggregation, as well as the structural remodeling of amyloid‐β fibrils by the compound epi‐gallocatechin gallate.     

A mathematical optimization framework for the design of nanopatterned surfaces

The recent explosion of capabilities to fabricate nanostructured materials to atomic precision has opened many avenues for technological advances but has also posed unique questions regarding the identification of structures that should serve as targets for fabrication. One material class for which identifying such targets is challenging are transition‐metal crystalline surfaces, which enjoy wide application in heterogeneous catalysis. The high combinatorial complexity with which patterns can form on such surfaces calls for a rigorous design approach. In this article, we formalize the identification of the optimal periodic pattern of a metallic surface as an optimization problem, which can be addressed via established algorithms. We conduct extensive computational studies involving an array of crystallographic lattices and structure‐function relationships, validating patterns that were previously known to be promising but also revealing a number of new, nonintuitive designs. © 2016 American Institute of Chemical Engineers AIChE J, 62: 3250–3263, 2016     

盐度对新型生物脱氮技术影响的研究进展

近年来,新型生物脱氮技术处理高盐含氮废水引起广泛关注,可耐受一定盐度的同时去除废水中的氮素,克服了传统生物脱氮存在的反应器占地面积大、工艺流程长和运行成本偏高等问题。本文综述了盐度对基于硝化-反硝化生化过程的新型脱氮技术（同步硝化反硝化技术和短程硝化反硝化技术）和基于厌氧氨氧化反应的新型脱氮技术[厌氧氨氧化技术、部分硝化-厌氧氨氧化技术、全程自养脱氮工艺（CANON）、限氧亚硝化与厌氧氨氧化相耦合（OLAND）]的影响。通过综述发现在盐度耐受范围内,新型技术脱氮性能影响较小,甚至会促进新型工艺脱氮,而超过一定范围后会显著抑制新型技术的脱氮性能,这主要是新型技术中多种微生物的相互作用及其自身活性受到盐度影响所致,在反应器中添加嗜盐菌和经过一定盐度驯化的微生物可处理更高盐度的含氮废水。最后文章指出加强盐度对新型脱氮技术中微生物群落结构及代谢模式的影响分析、耐盐脱氮微生物的筛选应用及微生物耐盐响应机制的研究是改进和提高自身技术处理性能的根本,已成为高盐含氮废水处理的研究方向。     

Additive Manufacturing of Polymer-Based Lubrication

The fast growth of 3D printing technology gives designers many ways to make structures that are hard to see. 3D printing lets you customize complex structures in any way you want and make rapid prototypes of materials. It enables you to simulate things more effectively. So far, experiments with polymer-based lubrication have been done on atomically smooth surfaces, under dynamic conditions, and on the nano- or micro-scale. Polymer-based lubrication in 3D printing has been studied in depth, which has made it possible to make significant, multifunctional 3D structures with microscale accuracy. It is a crucial way to approach lubrication and has sparked much scientific interest. A thorough literature review is done to keep track of the latest advances in 3D printing for structural polymer-based lubrication simulation. The design and lubrication performance quality of bio-inspired, different-sized simulation structures is given much attention. The material requirements, skills, and representative applications of various 3D printing technologies are summarized. The efficient directions for future research in designing and making 3D-printed lubrication structures are also pointed out.     

电凝聚水处理技术的新进展

首先简介了电凝聚法处理废水的基本原理，其过程和机理与化学混凝法基本相同。并着重阐述了近年来电凝聚技术在废水处理和给水净化方面的应用现状。其主要用于处理印染废水。在处理油乳胶、去除悬浮物及有机物等方面也取得了良好的效果。电凝聚可同时除去水中的有机物、细菌、浊度、重金属及其他毒物，是一种有前途的净水方法。人们还从改进电源技术、采用新型电极和改进电解槽设计等方面着手，以降低其处理能耗，这些正成为电凝聚研究的热点。     

Imaging of Small Animal Peripheral Artery Disease Models: Recent Advancements and Translational Potential

Peripheral artery disease (PAD) is a broad disorder encompassing multiple forms of arterial disease outside of the heart. As such, PAD development is a multifactorial process with a variety of manifestations. For example, aneurysms are pathological expansions of an artery that can lead to rupture, while ischemic atherosclerosis reduces blood flow, increasing the risk of claudication, poor wound healing, limb amputation, and stroke. Current PAD treatment is often ineffective or associated with serious risks, largely because these disorders are commonly undiagnosed or misdiagnosed. Active areas of research are focused on detecting and characterizing deleterious arterial changes at early stages using non-invasive imaging strategies, such as ultrasound, as well as emerging technologies like photoacoustic imaging. Earlier disease detection and characterization could improve interventional strategies, leading to better prognosis in PAD patients. While rodents are being used to investigate PAD pathophysiology, imaging of these animal models has been underutilized. This review focuses on structural and molecular information and disease progression revealed by recent imaging efforts of aortic, cerebral, and peripheral vascular disease models in mice, rats, and rabbits. Effective translation to humans involves better understanding of underlying PAD pathophysiology to develop novel therapeutics and apply non-invasive imaging techniques in the clinic.     

芳纶浆粕纤维在橡胶制品中的应用

随着欧美等地区开展禁止使用石棉的环境保护运动，芳轮浆粕纤维得到了迅速发展，它在橡胶制品领域中也得到了广泛应用，如在胶管、动力传送带、运输带、胶鞋鞋底等方面。与此同时，芳纶浆粕纤维在橡胶制品中的分散技术也得到了发展。可以预言，随着浆粕在橡胶料中分散性问题的解决，必将为橡胶制品领域工作者提供广阔的设计空间。     

含多重结构包覆载体技术的研究进展

概述了多重结构乳状液的结构类型、制备方法及其在药品、化妆品等领域的应用,综述了含多重结构的包覆载体,包括了脂质体、微胶囊和固体脂质纳米粒及其制备方法与研究现状,阐述了含多重结构的包覆载体的特性。     

Vinyl carbonate photopolymers with improved mechanical properties for biomedical applications

Recently, vinyl carbonates have been demonstrated to be a versatile alternative to acrylates and methacrylates in biomedical applications as they exhibit photoreactivity and mechanical properties on a level or even above (meth)acrylates. Furthermore, much lower cytotoxicity as well as degradation via a surface erosion mechanism qualify them for medical use. However, it is highly desirable to improve the mechanical properties of vinyl carbonates to reach the performance of PLA. Thus, the main focus of this study lies on designing vinyl carbonates with suitable functional groups that are capable of augmenting mechanical properties of vinyl carbonates, e.g. cyclic structures or urethane groups, and implementing them into the vinyl carbonate structures. Resulting monomers were tested regarding their photoreactivity and cytotoxicity. Furthermore, cured specimens were investigated concerning their mechanical properties. In addition, the thiol-ene reaction was utilized to further improve photoreactivity. The new vinyl carbonates exhibit excellent biocompatibility and photoreactivity that can be significantly enhanced through the addition of thiols onto the level of highly photoreactive acrylates. Most importantly, results showed that the mechanical properties could be improved onto the level of PLA and above.     

充分开拓小型可编程控器的潜能

采用了德国西门子公司Ｓ７－２００型ＰＬＣ，实现了六套电镀程序，三部引车，六个吊钩，４２个缸位的多工位工艺控制要求，长西门子公司ＳＴＥＰ７－ＭＩＣＲＯ／ＤＯＳ的强大编程功能，采用了模块化的子程序结构，公用了３．５Ｋ的内存空间，就成功地进行了３７次循环和１４５子程序的多重嵌套和反复用。     

炼油与化工一体化 有效利用原油资源--从多种化学反应剖析多产石化产品途径

介绍了炼油过程中多产石油化工原料的有关工艺技术,从化学结构转化角度阐明了理论依据.由于原油特别是重油中丰富的烷基碳、环烷碳和芳碳资源均能通过一定途径转化为低碳烯碳以及芳碳,其潜在资源超过单纯依靠石脑油所能提供的数量,因而在经济合理和技术可行的原则下尽量提高其转化率成为当前炼油-化工一体化的研究热点.     

用夹紧区原理确定多元恒回流比分批精馏最小回流比

夹紧区是精馏塔内出现的浓度几乎不变的区域,对于三元物系来说,根据夹紧区在塔内出现的位置可分为：上、中和下加紧区.在无穷板数和任一瞬时釜浓下选择不同的回流比可使分批精馏处于不同夹紧区下操作.文中讨论了三元恒回流比分批精馏过程中夹紧区的演变,在Rayleigh方程的基础上建立了应用夹紧区原理确定多元恒回流比分批精馏最小回流比的方法.该方法并不要求相对挥发度为常数,并且能准确计算顶浓,克服了通常所采用的Underwood公式法的缺陷,为多元分批精馏的简捷设计奠定了基础.     

使用FRP的乐器用代替材料的设计(一)乐器用代替材料的振动特性

对于乐器用代替材料的设计，通过振动测试系统测定了一些木质乐器材料的比动态模量和对数衰减系数等振动特性。将乐器用木材的振动特性同通用木材运行了比较。通常，从以上参数可以计算出各种音响特性，发现了乐器用木材的特点，与通用木材相比，具有高比动态模量和低对数衰减系数的特点。但从单向ＣＦＲＰ和ＣＦＲＰ的测试结果发现，这些材料不具备乐器用代替材料的特性。因此，仅用ＦＲＰ作为乐器用代替材料是不可能的。我们试制了     

A New Model for Solvent Extraction in Columns

Abstract

A new model is proposed for analyzing solvent extraction processes carried out in any type of column. Each column is treated as a series of well-defined equilibrium stages where the backmixing (other-phase carryover) between stages can be large. It is assumed that mass transfer effects can be modeled by a proper choice for stage height and backmixing. With this model, the same number of stages can be used for all extracted chemical components no matter what their distribution coefficients. Thus, this model greatly simplifies the calculations required when evaluating multicomponent solvent extraction processes and so, is more appropriate than either the Height of an Equivalent Theoretical Stage (HETS) or the Height of a Transfer Unit (HTU). Initial evaluation shows that the new model works as well as the HTU method and better than the HETS method when correlating actual pulse column data.     

Computerized generation of technological structures

This paper introduces an algorithm which can determine the technology structure containing given chemical technological steps and producing given final products from given initial inlet materials.

With the aid of the algorithm all solutions of the problem or the solution with minimal sum of weights can be obtained. In the latter the user assigns weight factors to the different technological steps. It is also possible to determine all solutions haveing a sum of weights not greater than a limit given by the user. The algorithm and the datastructure introduced provide grounds for designing technologies with multi-component materials and recirculations.     

MXenes and MXene-based (nano)structures: A perspective on greener synthesis and biomedical prospects

Generally, MXenes have been widely prepared using hazardous/harmful etchants or fluoride-containing reagents through laborious protocols without environmentally-friendly features. Thus, greener and eco-friendly techniques with mild conditions and safer agents/materials for the synthesis and functionalization of these structures should be focused to reduce or avoid the utilization of toxic and hazardous chemical agents, enhancing the biocompatibility and biosafety criteria. The manufacturing of high-quality MXenes and their derivatives with up-scalability, simplicity, high yields, and cost-effectiveness advantages for clinical and biomedical purposes should be a priority for research in this field. MXenes with unique electronic/electric, mechanical, thermal, optical and magnetic properties can be applied to improve the efficacy and functionality of intelligent nanosystems targeted for biomedical purposes. However, in addition to the up-scalability and environmentally-benign criteria, other critical aspects regarding the stability and cost-effectiveness as well as optimized conditions and functionalization processes should be addressed. Herein, recent advances of greener synthesis approaches for designing MXenes as well as their biomedical potentials are deliberated, focusing on important challenges and future perspectives.     

Control of morphology and electrical properties of self-organized graphenes in a plasma

The possibility of effective control of morphology and electrical properties of self-organized graphene structures on plasma-exposed Si surfaces is demonstrated. The structures are vertically standing nanosheets and can be grown without any catalyst and any external heating upon direct contact with high-density inductively coupled plasmas at surface temperatures not exceeding 673–723 K. Study of nucleation and growth dynamics revealed the possibility to switch-over between the two most common (turnstile- and maze-like) morphologies on the same substrates by a simple change of the plasma parameters. This change leads to the continuous or discontinuous native oxide layer that supports self-organized patterns of small carbon nanoparticles on which the structures nucleate. It is shown that by tailoring the nanoparticle arrangement one can create various three-dimensional architectures and networks of graphene nanosheet structures. We also demonstrate effective control of the degree of graphitization of the graphene nanosheet structures from the initial through the final growth stages. This makes it possible to tune the electrical resistivity properties of the produced three-dimensional patterns/networks from strongly dielectric to semiconducting. Our results contribute to enabling direct integration of graphene structures into presently dominant Si-based nanofabrication platform for next-generation nanoelectronic, sensor, biomedical, and optoelectronic components and nanodevices.     

Towards Efficient Nonenzymatic DNA Ligation: Comparing Key Parameters for Maximizing Ligation Rates and Yields with Carbodiimide Activation**

Chemical ligation is an important tool for the generation of synthetic DNA structures, which are used for a wide range of applications. Surprisingly, reported chemical ligation yields can range from 30 to 95 % for the same chemical activating agent and comparable DNA structures. We report a systematic study of DNA ligation by using a well-defined bimolecular test system and a water-soluble carbodiimide (EDC) as a phosphate-activating agent. Our results emphasize the interplay between template-substrate complex stability and the rates of the chemical steps of ligation, with 3′ phosphate substrates providing yields near 100 % after 24 hours for particularly favorable reaction conditions. Ligation rates are also shown to be sensitive to the identity of the base pairs flanking a nick site, with as much as threefold variation. Finally, the observation that DNA substrates are modified by EDC at rates that can be comparable with ligation rates emphasizes the importance of considering side reactions when designing protocols to maximize ligation yields.     

Analysis and optimization of continuous organic solvent nanofiltration by membrane cascade for pharmaceutical separation

The major part of the production costs of pharmaceuticals can be imputed to the downstream processing, where membrane technologies have to deal with some challenges as separations involving solutes with similar sizes or solvent recovery and recycling. This work contributes to the progress in the design of continuous organic solvent nanofiltration systems for this purpose and includes the configuration of dual membrane cascades, sensitivity analysis of the operation variables, and economic optimization as innovations. Analyzed configurations include multistage cascades up to three stages, and dual membrane cascades up to five stages. The total costs (TC) were chosen as the formulated objective function to minimize in the economic optimization strategy. The treatment of the residual stream leaving the system resulted the main cost of the process (more than 85% for dual cascades), but the solvent recovery units can significantly reduce the TC (64–77% depending on the required solvent quality). © 2014 American Institute of Chemical Engineers AIChE J, 60: 931–948, 2014