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Numerical analysis of hydroabrasion in a hydrocyclone

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Petroleum Science 2016年第2期13卷 304-319页

作者： Mehdi Azimian Hans-Jorg bart Department of Mechanical and Process Engineering University of Kaiserslautern 67663 Kaiserslautern Germany

The velocity profiles and separation efficiency curves of a hydrocyclone were predicted by an Euler-Euler approach using a computational fluid dynamics tool ANSYS-CFX 14.5. The Euler-Euler approach is capable of considering the particle-particle interactions and is appropriate for highly laden liquid-solid mixtures. Pre- dicted results were compared and validated with experi- mental results and showed a considerably good agreement. An increase in the particle cut size with increasing solid concentration of the inlet mixture flow was observed and discussed. In addition to this, the erosion on hydrocyclone walls constructed from stainless steel 410, eroded by sand particles （mainly SiOz）, was predicted with the Euler-La- grange approach. In this approach, the abrasive solid particles were traced in a Lagrangian reference frame as discrete particles. The increases in the input flow velocity, solid concentration, and the particle size have increased the erosion at the upper part of the cylindrical body of the hydrocyclone, where the tangential inlet flow enters the hydrocyclone. The erosion density in the area between the cylindrical to conical body area, in comparison to other parts of the hydrocyclone, also increased considerably. Moreover, it was observed that an increase in the particle shape factor from 0.1 to 1.0 leads to a decrease of almost 70 % in the average erosion density of the hydrocyclone wall surfaces.

关键词： Hydrocyclone Computational fluiddynamicS (CFD) Separation efficiency - Erosion rateErosion impact parameters

From Single Droplet to Column Design

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Tsinghua Science and Technology 2006年第2期11卷 212-216页

作者： Hans-Jrg bart Institute of Thermal Process Engineering TU Kaiserslautern D-67653 Kaiserslautern Germany

The technique state to design counter-current extraction columns is based on the performance of pilot plant experiments. The modelling is then either with the equilibrium or dispersion model, whereas in the latter the dispersion coefficient accounts for all hydrodynamic non-idealities. A new approach uses single droplet experiments to obtain the basic laws and functions governing droplet breakage, coalescence, relative velocity, and axial dispersion when using droplet populance balance models （DPBM）. The hydrodynamics simulation results show that the mean Sauter diameter, hold-up, and concentration profiles could be well predicted, which promotes the use of DPBM models for further applications in industrial scale.

关键词： single droplet column design countercurrent extraction droplet populance balance model

New insights into the regulation of cholesterol eft from the sperm membrane

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Asian Journal of Andrology 2015年第4期17卷 561-567页

作者： Tamara Leahy bart M Gadella Faculty of Veterinary Science University of Sydney 2006 Sydney Australia Department of Farm Animal Health and of Biochemistry and Cell Biology Faculty ofVeterinary Medicine Utrecht University Yalelaan 2 3584 CM Utrecht The Netherlands.

Cholesterol is an essential component of the mammalian plasma membrane because it promotes membrane stability without comprising membrane fluidity. Given this important cellular role, cholesterol levels are tightly controlled at multiple levels. It has been clearly shown that cholesterol redistribution and depletion from the sperm membrane is a key part of the spermatozoon＇s preparation for fertilization. Some factors that regulate these events are described （e.g., bicarbonate, calcium） but the mechanisms underlying cholesterol export are poorly understood. How does a hydrophobic cholesterol molecule inserted in the sperm plasma membrane enter the energetically unfavorable aqueous surroundings？ This review will provide an overview of knowledge in this area and highlight our gaps in understanding. The overall aim is to better understand cholesterol redistribution in the sperm plasma membrane, its relation to the possible activation of a cholesterol transporter and the role of cholesterol acceptors. Armed with such knowledlze, sl）erm handlin~ techniques can be adapted to better prepare spermatozoa for in vitro and in vivo fertilization.

关键词： ATP binding cassette transporters albumin high-density lipoprotein lipid rafts membrane fluidity membranemicrodomains membrane packing oxysterols reverse cholesterol transport sterol transporters

Plasma-based CO_(2) conversion:How to correctly analyze the performance?

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Journal of Energy Chemistry 2023年第11期86卷 180-196,I0005页

作者： bart Wanten Rani Vertongen Robin De Meyer Annemie Bogaerts Research Group PLASMANT Department of ChemistryUniversity of AntwerpUniversiteitsplein 12610 AntwerpBelgium Research group EMAT Department of PhysicsUniversity of AntwerpGroenenborgerlaan 1712020 AntwerpBelgium

Plasma-based CO_(2)conversion is promising for carbon capture and ***,inconsistent reporting of the performance metrics makes it difficult to compare plasma processes systematically,complicates elucidating the underlying mechanisms and compromises further development of this ***,this critical review summarizes the correct definitions for gas conversion in plasma reactors and highlights common errors and inconsistencies observed throughout *** is done for pure CO_(2)splitting,dry reforming of methane and CO_(2)*** demonstrate that the change in volumetric flow rate is a critical aspect,inherent to these reactions,that is often not correctly taken into *** dry reforming of methane and CO_(2)hydrogenation,we also demonstrate inconsistent reporting of energy efficiency,and through numerical examples,we show the significance of these ***,we discuss how to measure changes in volumetric flow rate,supported by data from two experimental examples,showing that the sensitivity inherent to a standard component and a flow meter is essential to consider when deriving the performance ***,some general recommendations and good practices are *** paper aims to be a comprehensive guideline for authors,to encourage more consistent calculations and stimulate the further development of this technology.

关键词： Plasma CO_(2) Dry reforming of methane CO_(2) hydrogenation Conversion Performance

Preliminary assessment of growth and survival of green alder(Alnus viridis), a potential biological stabilizer on fly ash disposal sites

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Journal of Forestry Research 2015年第1期26卷 131-136页

作者： Marcin Pietrzykowski Wojciech Krzaklewski bartomiej Wo Department of Forest Ecology Forest FacultyUniversity of Agriculture in Krakow

This paper presents preliminary assessment of seedling survival and growth of green alder（Alnus viridis（Chaix） DC. in Lam. ＆ DC.） planted on fly ash disposal sites. This kind of post-industrial site is extremely hard to biologically stabilize without top-soiling. The experiment started with surface preparation using NPK start-up mineral fertilizer at 60–36–36 kg ha-1followed by initial stabilization through hydro-seeding with biosolids（sewage sludge 4 Mg ha-1dry mass） and a mixture of grasses（Dactylis glomerata L. and Lolium multiflorum Lam.）（200 kg ha-1）. Subsequently, three-years-old green alder seedlings were planted in plots on two substrate variants：the control（directly on combustion waste） and plots with3 dm3 lignite culm from a nearby mine introduced into the planting pit. Five years of preliminary monitoring show good survival seedling rates and growth parameters（height（h）, average increase in height（Dh）, number of shoots（L o）and leaf nitrogen supply in the fly ash disposal *** of the site with a combination of lignite culm in planting pits and preliminary surface preparation by hydroseeding and mineral fertilization had the most positive effect on green alder seedling parameters. The results indicate that it is possible and beneficial to use green alder for biological stabilization on fly ash disposal sites.

关键词： Fly ash Green alder Seedlings survival Growth Biological stabilisation

On Some Families of Smooth Affine Spherical Varieties of Full Rank

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Acta Mathematica Sinica,English Series 2018年第3期34卷 563-596页

作者： Kay PauLUS Guido PEZZINI bart VAN STEIRTEGHEM Department Mathematik FA U Erlangen-Niirnberg 91058 Erlangen Germany Dipartimento di Matematica 'Sapienza' Universith di Roma 00185 Roma Italy Department Mathematik FA U Erlangen-Niirnberg & Department of MathematicsMedgar Evers College-City University of New York Brooklyn New York 11225 USA

Let G be a complex connected reductive group. Losev has shown that a smooth affine spherical G-variety X is uniquely determined by its weight monoid, which is the set of irreducible representations of G that occur in the coordinate ring of X. In this paper we use a combinatorial characterization of the weight monoids of smooth affine spherical varieties to classify：（a） all such varieties for G = SL（2） × C~×and（b） all such varieties for G simple which have a G-saturated weight monoid of full rank. We also use the characterization and Knop＇s classification theorem for multiplicity free Hamiltonian manifolds to give a new proof of Woodward＇s result that every reflective Delzant polytope is the moment polytope of such a manifold.

关键词： Affine spherical variety weight monoid multiplicity free Hamiltonian manifold moment polytope

Reflection and Critique： Philosophy＇s Hope for Education

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Frontiers of Philosophy in China 2013年第2期8卷 266-272页

作者： bart Raymaekers Institute of Philosophy Katholieke Universiteit Leuven 3000 Leuven Belgium

1 IntroductionUniversities still, today, enjoy a specific type of respectability. Undoubtedly, this could be explained by the fact that universities, from medieval times onwards, have belonged to the cultural and intellectual landscape in general and to educational heritage in particular. From a distance, it looks like they are braving, with obvious confidence, every day＇s delusions; most people look at universities as quite stable institutions. Of course, there are good reasons for this： Universities have been and still are offering programs and training, consisting of individual courses, offered by professors. At the end, in exchange for ongoing efforts, students can get a degree, most likely opening the door to interesting, meaningful jobs with decent pay.

关键词： Universities Higher education Hope Social evolution Public authorities Educational research Educational philosophies Critical thinking

Defining the Value of Extracorporeal Liver Support in Acute and Acute-on-chronic Liver Failure

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Journal of Clinical and Translational Hepatology 2023年第3期11卷 517-520页

作者： bart van Hoek Department of Gastroenterology and Hepatology C4-Pand Transplantation CenterLeiden University Medical CenterLei denthe Netherlands

Next to acute liver failure(ALF)without previous liver dis-ease,the concept of acute-on-chronic liver failure(ACLF)has been developed.1,2 In most cases patients developing ACLF first have acute decompensation(AD)of cirrhosis,of-ten with ascites,hepatic encephalopathy,variceal bleeding,or hepatorenal *** can be induced by infection or other factors,like hepatitis *** ALF and ACLF develop rapidly,ALF within 26 weeks of onset,ACLF in 2-4 weeks,and both conditions share the symptoms of a fail-ing *** detoxification with jaundice and hepatic encephalopathy,and impaired synthetic capacity of the liver with changes in coagulation parameters are part of these *** both ALF and ACLF multi-organ failure can de-velop,including hemodynamic instability,respiratory failure and acute kidney injury,and patients become susceptible to *** standard medical treatment(SMT)in the intensive care unit has improved over the years,2,3 both con-ditions often lead toward death,unless a timely liver trans-plantation(LT)is possible.4,5.

关键词： acute impaired Acute

Transition Modelling with the k-Ω Turbulence Model and an Intermittency Transport Equation

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Journal of Thermal Science 2004年第3期13卷 220-225页

作者： Koen LODEFIER bart MERCI Chris De LANGHE Erik DICK Ghent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent BelgiumGhent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent BelgiumGhent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent BelgiumGhent University Dept. of Flow Heat and Combustion Mechanics Sint-Pietersnieuwstraat 41 B-9000 Gent Belgium

In gas turbine engines, laminar-turbulent transition occurs. However, generally, the turbulence models to describe such transition results in too early and too short transition. Combining a turbulence model with a description of intermittency, i.e. the fraction of time the flow is turbulent during the transition phase, can improve it. By letting grow the intermittency from zero to unity, start and evolution of transition can be imposed. In this paper, a method where a dynamic equation of intermittency combining with a two-equation k-ωturbulence model is described. This intermittency factor is a premultiplicator of the turbulent viscosity computed by the turbulence model. Following a suggestion by Menter et al.[1], the start of transition is computed based on local variables.

关键词： bypass transition intermittency SST turbulence model.