Crossflow microfiltration modelling and mechanical means to prevent membrane fouling

The definition, history and applications of Microfiltration (MP) are briefly reviewed in Chapter 1. The physical mechanisms and mathematical models of the filtration process including concentration polarization (CP), gel polarization (GP) and pore blocking are given in Chapter 2. Crossflow microfiltration membrane fouling and the deposition of solids onto the filter surface have been investigated using a process fluid (seawater), latex and a ground mineral. The performance of various membrane materials has also been studied, including: acrylonitrile, polypropylene, PTFE, ceramic and stainless steel. The seawater filtration work showed in Chapter 3 that good filtrate flux rates can be maintained if material fouling or depositing on the membrane can be prevented from entering the membrane structure. A surface deposit may be removed by mechanical means such as backflushing with permeate or compressed air. This aspect of the work indicated that a more comprehensive study of fouling was required. Existing crossflow filtration membrane models did not adequately represent even the simplest filtration when penetration of the membrane structure applied. Such conditions occurred during latex filtration in Chapter 4. Latex of varying sizes and density were manufactured and filtrations using acrylonitrile membranes were performed. Considerable deposition of latex inside the membrane pores occurred despite the nominal rating of the membrane being less than the latex particle diameter. Thus the membranes relied on a depth filtration mechanism rather than a surface straining mechanism for filtration effectiveness. A standard filtration blocking model was modified for use in crossflow microfiltration, coupled with a mass balance on the amount of material filtered. This mathematical model was then used to predict and correlate the rate of filtration flux decay with respect to filtration time during crossflow filtration. The model provided acceptable accuracy and is an improvement on existing empirical models for the flux decay period. Under the circumstances of membrane penetration it is advisable to minimise the amount of material entering the membrane structure. Mechanical means to achieve this were investigated and a novel anti-fouling method using a centrifugal field force and enhanced shear stress at the membrane surface was developed. The filtration of limestone slurries with three different tubular filters are presented in Chapter 5, in which one filter was conventional, the other two novel ones were specially designed for the separation of particles with a density different from that of the liquid, one used a helical channel around the filter, and the other had tangential inlet and outlet endcaps. The centrifugal force produced by the spinning flow around these two filters retarded the approach of particles towards the membrane surface so that the particle deposition was reduced. The results showed such a system was energy efficient, saving 20 % of the energy required to effect a separation of mineral material compared with using the membrane in a more conventional way

Interconnecting bilayer networks

A typical complex system should be described by a supernetwork or a network of networks, in which the networks are coupled to some other networks. As the first step to understanding the complex systems on such more systematic level, scientists studied interdependent multilayer networks. In this letter, we introduce a new kind of interdependent multilayer networks, i.e., interconnecting networks, for which the component networks are coupled each other by sharing some common nodes. Based on the empirical investigations, we revealed a common feature of such interconnecting networks, namely, the networks with smaller averaged topological differences of the interconnecting nodes tend to share more nodes. A very simple node sharing mechanism is proposed to analytically explain the observed feature of the interconnecting networks.Comment: 9 page

临床压疮管理简易方法探究

To guarantee the fulfilling of nursing for pressure sores patients efficiently and normatively, we established "The quality evaluation standard of pressure score management", in which the content were comprehensive and the standard were definite.It is widely applied for clinical supervision, unified examination method, to guide clinical work, narrow the difference of evaluation, popularize the knowledge of pressure scores, improve the ability of would disposal, reported compliance rates of high risk of pressure scores increased as well as the rate of cure and nursing care of patients with pressure scores. Nursing care of patients with pressure sore was from passive to active, measures are effectively implemented, the management level of the skin was improved so that it turns out to be a simple and effective method. 为保证压疮护理各项措施的有效、规范落实，制定了《压疮管理质量评价标准》，其涵盖内容全面，工作标准明确。并依此进行临床督导，统一检查方法，指引临床工作，缩小评估差异，普及压疮知识，提高了创面处置能力，高危压疮上报符合率及压疮治愈好转率提高，压疮护理由被动变主动，措施得到有效落实，提高了皮肤管理水平，方法简单有效

Model Checking Quantum Continuous-Time Markov Chains

Verifying quantum systems has attracted a lot of interests in the last decades. In this paper, we initialise the model checking of quantum continuous-time Markov chain (QCTMC). As a real-time system, we specify the temporal properties on QCTMC by signal temporal logic (STL). To effectively check the atomic propositions in STL, we develop a state-of-the-art real root isolation algorithm under Schanuel's conjecture; further, we check the general STL formula by interval operations with a bottom-up fashion, whose query complexity turns out to be linear in the size of the input formula by calling the real root isolation algorithm. A running example of an open quantum walk is provided to demonstrate our method

(Bis{2-[3-(2,4,6-trimethyl­benz­yl)imid­azolin-2-yliden-1-yl-κC 2]-4-methyl­phenyl}amido-κN)chloridopalladium(II)

The coordination geometry about the Pd centre in the title compound, [Pd(C40H42N5)Cl], is approximately square-planar. The CNC pincer-type N-heterocyclic carbene ligand binds to the Pd atom in a tridentate fashion by the amido N atom and the two carbene atoms and generates two six-membered chelate rings, completing the coordination

Synthesis of two novel chiral building blocks for anti- and syn-1,3-diols

844-84

Distances and classification of amino acids for different protein secondary structures

Window profiles of amino acids in protein sequences are taken as a description of the amino acid environment. The relative entropy or Kullback-Leibler distance derived from profiles is used as a measure of dissimilarity for comparison of amino acids and secondary structure conformations. Distance matrices of amino acid pairs at different conformations are obtained, which display a non-negligible dependence of amino acid similarity on conformations. Based on the conformation specific distances clustering analysis for amino acids is conducted.Comment: 15 pages, 8 figure