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Influence of entrainer recycle for batch heteroazeotropic distillation

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Frontiers of Chemical Science and Engineering 2018年第4期12卷 643-659页

作者： Laszlo Hegely peter Lang Department of Building Service and Process Engineering Faculty of Mechanical Engineering Budapest University of Technology and EconomicsMuegyetem rkp.3-9Hungary

Dehydration of isopropanol applying batch heteroazeotropic distillation with toluene as entrainer (E) is investigated. The composition of the feed is near to that of the isopropanol (A)-water (B) azeotrope. The effects of recycling the entrainer and the off-cut are studied by dynamic simulation with a professional flow-sheet simulator. Three consecutive batches (one production cycle) is studied. Both operational modes (Mode I: decantation after distillation and Mode II: decantation during distillation) are simulated. For Mode II, calculations are performed both for Strategy A (distillate from the aqueous (E-lean) phase only) and Strategy B (partial withdrawal of the organic (E-rich phase), as well). The E-rich phase, the final column hold-up and the off-cut (Mode II only) are recycled to the next batch. The influence of the following parameters are determined: quantity of entrainer, reflux ratios of the steps. The variations caused by the recycling in the 2nd and 3rd batches are also shown. The best results (lowest specific energy demand and highest recovery of A) are obtained by Mode II, Strategy A. Recycling increases the recovery, and drastically diminishes the entrainer consumption. However, it makes the production slower and decreases the quantity of fresh feed that can be processed.

关键词： batch distillation heteroazeotropic distillation operational policies off-cut recycle entrainer

Disentangling confusions in inflorescence morphology:Patterns and diversity of reproductive shoot ramification in angiosperms

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Journal of Systematics and Evolution 2010年第4期48卷 225-239页

作者： peter K.ENDRESS Institute of Systematic Botany University of Zurich

Terminology of inflorescence diversity has often been used in a confusing way in the literature,partly because it was based on uncritical and outdated *** particular,the terms cyme,thyrse,and panicle have been *** a more critical classification worked out by several authors is available,it is unfortunately not in general use because most of the relevant publications are written in *** addition,some terms have not been used in the same way by morphologists and developmental *** present review attempts to remedy the situation with a simple outline of a classification based on:(i)different branching patterns;(ii)differential elongation of axes of different orders;and(iii)repetition of basic ramification patterns in different *** and cymose branching are two extreme patterns;the former with limitation of axial orders to two,the second with limitation of lateral axes of each order to *** a branching system,a sequence of racemose→cymose and,within the cyme,of dichasial→monochasial is common,but the reverse sequence generally does not *** and evolutionary aspects of inflorescences are briefly *** patterns are often stable in larger *** of mutants studied in developmental genetic studies are mainly altered in flower or branch numbers or relative branch length,but not in branching *** is also a contribution towards the goal of a unified terminology for the different fields of biology dealing with inflorescences.

关键词： branching patterns cymose inflorescence panicle racemose reproductive shoot thyrse

PRECONDITIONING BLOCK LANCZOS ALGORITHM FOR SOLVING SYMMETRIC EIGENVALUE PROBLEMS

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Journal of Computational Mathematics 2000年第4期18卷 365-374页

作者： Hua Dai peter Lancaster Nanjing University of Aeronautics and Astronautics Naming210018China University of Calgary CalgaryCanada

A preconditioned iterative method for computing a few eigenpairs of large sparse symmetric matrices is presented in this paper. The proposed method which combines the preconditioning techniques with the efficiency of block Lanczos algorithm is suitable for determination of the extreme eigenvalues as well as their multiplicities. The global convergence and the asymptotically quadratic convergence of the new method are also demonstrated. [ABSTRACT FROM AUTHOR]

关键词： eigenvalue eigenvector sparse matrices Lanczos method preconditioning

FUNCTIONAL POLYHYDROXYALKANOATES SYNTHESIZED BY MICROORGANISMS

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Chinese Journal of Polymer Science 2000年第5期18卷 389-396页

作者： peter H.Yu Open Laboratory of Chiral Technology Hong Kong Polytechnic University Hong Kong China

Many bacteria have been found to synthesize a family of polyesters termed polyhydroxyalkanoate, abbreviated as PHA. Some interesting physical properties of PHAs such as piezoelectricity, non-linear optical activity, biocompatibility and biodegradability offer promising applications in areas such as degradable packaging, tissue engineering and drug delivery. Over 90 PHAs with various structure variations have been reported and the number is still increasing. The mechanical property of PHAs changes from brittle to flexible to elastic, depending on the side-chainlength of PHA. Many attempts have been made to produce PHAs as biodegradable plastics using various microorganisms obtained from screening natural environments, genetic engineering and mutation. Due to the high production cost, PHAs still can not compete with the nondegradable plastics, such as polyethylene and polypropylene. Various processes have been developed using low cost raw materials for fermentation and an inorganic extraction process for PHA purification. However, a super PHA production strain may play the most critical role for any large-scale PHA production. Our recent study showed that PHA synthesis is a common phenomenon among bacteria inhabiting various locations, especially oil-contaminated soils. This is very important for finding a suitable bacterial strain for PHA production. In fact, PHA production strains capable of rapid growth and rapid PHA synthesis on cheap molasses substrate have been found on molasses contaminated soils. A combination of novel properties and lower cost will allow easier commercialization of PHA for many applications.

关键词： polyhydroxybutyrate polyhydroxyalkanoate biopolymer polyester

The effect of inlet conditions on the flow and heat transfer in multiple rotating cavity with axial throughflow

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航空动力学报 2007年第5期22卷 683-693页

作者： Christopher Long peter Childs TFMRC Department of Engineering and Design University of Sussex Brighton BN1 9QT UK

This paper discusses experimental results from two different build configurations of a heated multiple rotating cavity test rig. Measurements of heat transfer from the discs and tangential velocities are presented. The test rig is a 70% full scale version of a high pressure compressor stack of an axial gas turbine engine. Of particular interest are the internal cylindrical cavities formed by adjacent discs and the interaction of these with a central axial throughflow of cooling air. Tests were carried out for a range of non-dimensional parameters representative of high pressure compressor internal air system flows (Reφup to 5×106 and ReΦup to 2×105).Two different builds have been tested. The most significant difference between these two build configurations is the size of the annular gap between the (non-rotating) drive shaft and the bores of the discs. The heat transfer data were obtained from thermocouple measurements of surface temperature and a conduction solution method. The velocity measurements were made using a two component, LDA system. The heat transfer results from the discs show differences between the two builds. This is attributed to the wider annular gap allowing more of the throughflow to penetrate into the cavity. There are also significant differences between the radial distributions of tangential velocity in the two builds of the test rig. For the narrow annular gap, there is an increase of non-dimensional tangential velocity Vφ/Ωr with radial location to solid body rotation Vφ/Ωr=*** the wider annular gap, the non-dimensional velocities show a decrease with radial location to solid body rotation.

关键词：轴向直流热转移旋转式孔进口接头

Spatially-Structured Sharing Technique for Multimodal Problems

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Journal of Computer Science & Technology 2008年第1期23卷 64-76页

作者： Grant Dick peter Whigham Department of Information Science University of OtagoDunedin

Spatially-structured populations are one approach to increasing genetic diversity in an evolutionary algorithm （EA）. However, they are susceptible to convergence to a single peak in a multimodal fitness landscape. Niching methods, such as fitness sharing, allow an EA to maintain multiple solutions in a single population, however they have rarely been used in conjunction with spatially-structured populations. This paper introduces local sharing, a method that applies sharing to the overlapping demes of a spatially-structured population. The combination of these two methods succeeds in maintaining multiple solutions in problems that have previously proved difficult for sharing alone （and vice-versa）.

关键词： evolutionary algorithm multimodal problem domain sharing spatially-structured population

DECAGONAL QU ASICRYSTALLINE ELLIPTICAL INCLUSIONS UNDER THERMOMECHANICAL LOADING

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Acta Mechanica Solida Sinica 2014年第5期27卷 518-530页

作者： Xu Wang peter Schiavone School of Mechanical and Power Engineering East China University of Science and Technology Department of Mechanical Engineering University of Alberta 4-9 Mechanical Engineering Building Edmonton

In this work, an elegant method is proposed to derive the thermoelastic field in- duced by thermomechanical loadings in a decagonal quasicrystalline composite composed of an infinite matrix reinforced by an elliptical inclusion. The thermomechanical loadings include a uniform temperature change, remote uniform in-plane heat fluxes and remote uniform in-plane stresses. The corresponding boundary value problem is ultimately reduced to the solution of two independent sets of four coupled linear algebraic equations, each of which involves four complex constants characterizing the internal stress field. The solution demonstrates that a uniform tem- perature change and remote uniform stresses will induce an internal uniform stress field, and that uniform heat fluxes will result in a linearly distributed internal stress field within the elliptical inclusion. The induced uniform rigid body rotation within the inclusion is given explicitly.

关键词： elliptical inclusion thermomechanical loadings decagonal quasicrystal complexvariable method

PSA screening-for whom and when?

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Asian Journal of Andrology 2019年第1期21卷 3-5页

作者： peter Albers Department of Urology Dusseldorf University HospitalHeinrich-Heine-UniversityMoorenstr.5 D-40225DusseldorfGermany.

Reasons for and against screening of,prostate cancer have been discussed widely over the last *** 2014,the European Randomized Trial for Screening of Prostate Cancer(ERSPC)has reported a relative reduction of the cancer-specific survival of 27%in participants who definitely followed the *** relative advantage has proven to be stable from year 7 to year 13 after the beginning of ***,the disadvantages of overdiagnosis and overtreatment are the downsides of a population-based screening *** given the overall advantage of screening,a risk-adapted prostate-specific antigen(PSA)screening using a baseline PSA value at ages 45-50 may significantly reduce the number needed to diagnose maintaining the benefits of *** is a randomized risk-adapted screening trial currently ongoing in Germany to answer this important question.

关键词： PSA ERSPC

Carbohydrate malabsorption in patients with non-specific abdominal complaints

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World Journal of Gastroenterology 2007年第43期13卷 5687-5691页

作者： peter Born Department of Internal Medicine Tirschenreuth District Hospital Tirschenreuth 95643 Germany

Non-specific abdominal complaints are a considerable problem worldwide. Many patients are affected and many differential diagnoses have to be considered. Among these, carbohydrate malabsorption seems to play an important role. However, so far, only incomplete absorption of lactose is broadly accepted, while the malabsorption of fructose and sorbitol is still underestimated, although in many parts of the world it is much more frequent. Despite the success of dietary interventions in many patients, there are still a lot of unanswered questions that make further investigations

关键词： Non-specific abdominal disorders Carbohydrate malabsorption Fructose Sorbitol Lactose Dietary intervention