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Solution of shallow-water equations using least-squares finite-element method

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Acta mechanica Sinica 2008年第5期24卷 523-532页

作者： S.j. Liang j,-H, Tang m.-S. Wu Department of marine Environmental Informatics National Taiwan Ocean UniversityKeelung 20224 Taiwan China Department of Bioenvironmental Engineering Chung-Yuan Christian University Chung-Li 32023 Taiwan China Department of Geographic Information Systems Feng Chia University Taichung 40724 Taiwan China

A least-squares finite-element method （LSFEm） for the non-conservative shallow-water equations is presented. The model is capable of handling complex topography, steady and unsteady flows, subcritical and supercritical flows, and flows with smooth and sharp gradient changes. Advantages of the model include：（1） sources terms, such as the bottom slope, surface stresses and bed frictions, can be treated easily without any special treatment; （2） upwind scheme is no needed; （3） a single approximating space can be used for all variables, and its choice of approximating space is not subject to the Ladyzhenskaya-Babuska-Brezzi （LBB） condition; and （4） the resulting system of equations is symmetric and positive-definite （SPD） which can be solved efficiently with the preconditioned conjugate gradient method. The model is verified with flow over a bump, tide induced flow, and dam-break. Computed results are compared with analytic solutions or other numerical results, and show the model is conservative and accurate. The model is then used to simulate flow past a circular cylinder. Important flow charac-teristics, such as variation of water surface around the cylinder and vortex shedding behind the cylinder are investigated. Computed results compare well with experiment data and other numerical results.

关键词： Least-square finite-element method,Shallow-water equations Dam-break Vortex shedding

magnetically actuated glaucoma drainage devicefor regulating intraocular pressure afterimplantation

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microsystems & Nanoengineering 2023年第4期9卷 91-105页

作者： Inês C.F.Pereira Ralph j.S.van mechelen Hans m.Wyss Leonard Pinchuk Henny j.m.Beckers jaap m.j.den Toonder microsystems Department of Mechanical EngineeringEindhoven University of Technology5600MB EindhovenThe Netherlands Institute for Complex molecular Systems(ICmS) Eindhoven University of Technology5600MB EindhovenThe Netherlands University Eye Clinic maastricht Maastricht University Medical Centre+(MUMC+)6202AZ MaastrichtThe Netherlands InnFocus Inc.a Santen CompanyMiamiFlorida 33186USA Ophthalmic Biophysics Center Bascom Palmer Eye InstituteUniversity of Miami Miller School of MedicineMiamiFlorida 33136USA

The key risk factor for glaucoma is increased intraocular pressure (IOP). Glaucoma drainage devices implanted in theeye can reduce IOP and thus stop disease progression. However, most devices currently used in clinical practice arepassive and do not allow for postsurgical IOP control, which may result in serious complications such as hypotony (i.e.,excessively low IOP). To enable noninvasive IOP control, we demonstrate a novel, miniature glaucoma implant that willenable the repeated adjustment of the hydrodynamic resistance after implantation. This is achieved by integrating amagnetic microvalve containing a micropencil-shaped plug that is moved using an external magnet, thereby openingor closing fluidic channels. The microplug is made from biocompatible poly(styrene-block-isobutylene-block-styrene)(SIBS) containing iron microparticles. The complete implant consists of an SIBS drainage tube and a housing elementcontaining the microvalve and fabricated with hot embossing using femtosecond laser-machined glass molds. Usingin vitro and ex vivo microfluidic experiments, we demonstrate that when the microvalve is closed, it can providesufficient hydrodynamic resistance to overcome hypotony. Valve function is repeatable and stable over time. Due to itssmall size, our implant is a promising, safe, easy-to-implant, minimally invasive glaucoma surgery device.

关键词： enable implantation overcome

Photoluminescence characteristics of soft PZT 53/47 ceramic doped at A and/or B sites

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journal of Advanced Ceramics 2018年第2期7卷 109-116页

作者： m.D.DURRUTHY-RODRíGUEZ j.j.GERVACIO-ARCINIEGA m.HERNáNDEZ-GARCíA j.m.YánEZ-LImóN Universidad Nacional Evangélica Departamento de Física Aplicada Instituto de CibernéticaMatemáticay FísicaCITMA Catedrático CONACYT-Facultad de Ciencias Físico matemáticas Benemérita Universidad Autónoma de Puebla CINVESTAV-Unidad Querétaro del IPN Libramiento Norponiente 2000Fracc.Real de Juriquilla

This study presents the photoluminescence characteristics of the PZT 53/47 system doped at A and/or B sites, with Nb(PZTN), La(PLZT), and Nb–La(PLZTN) in the concentration range from 0.2 to 1.0 molar fraction. The intensity of the emission bands of the system PZTN is two orders higher than the intensity of the emission bands of the systems PLZT and PLZTN, and these emission bands are located at 1.73 eV(718 nm), 2.56 eV(485 nm), and 2.93 eV(424 nm). The origin of the luminescence in these systems is associated with lead and oxygen vacancies produced during the sintering process. The results from X-ray diffraction(XRD) show a mixture of rhombohedral and tetragonal phases. The system PZTN shows a higher tetragonal phase concentration, while PLZT and PLZTN systems show a higher rhombohedral phase concentration. The cell volume shows an increase with dopant concentration only in the case of the PLZTN system. The band gap energy shows a small variation in the PZTN and PLZTN cases around 3.0 eV, a close value to the band gap energy of the pure PZT 53/47 sample. The system PLZT shows an increasing behavior until 4.41 eV for the higher dopant concentration.

关键词： photoluminescence PZT ceramics band structure X-ray diffraction(XRD)

Recycling of spent lithium-ion batteries as a sustainable solution to obtain raw materials for different applications

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journal of Energy Chemistry 2023年第4期79卷 118-134页

作者： V.m.Leal j.S.Ribeiro E.L.D.Coelho m.B.j.G.Freitas Federal University of Espírito Santo Department of ChemistryLaboratory of Electrochemistry and ElectrochemistryAv.Fernando Ferrari514VitóriaES 29075-910Brazil

Lithium-ion batteries(LIBs)containing graphite as anode material and LiCoO_(2),Limn_(2)O_(4),and LiNi_(x)mn_(y)Co_(z)O_(2) as cathode materials are the most used worldwide because of their high energy density,capacitance,durability,and ***,such widespread use implies the generation of large amounts of electronic *** is estimated that more than 11 million ton of LIBs waste will have been generated by *** recycling can contribute to minimizing environmental contamination and reducing production costs through the recovery of high-value raw materials such as lithium,cobalt,and *** most common processes used to recycle spent LIBs are pyrometallurgical,biometallurgical,and *** the current scenario,it is necessary to develop environmentally friendly methods to recycle batteries and synthesize materials with multiple technological *** study presents a review of industrial and laboratory processes for recycling spent LIBs and producing materials that can be used in new batteries,energy storage devices,electrochemical sensors,and photocatalytic reactions.

关键词： Li-ion batteries Recycling Cathode Battery Hydrometallurgical Pyrometallurgical

Gas exchange and water relations of young potted loquat *** under progressive drought conditions

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journal of Integrative Agriculture 2018年第6期17卷 1360-1368页

作者： A.Stellfeldt m.A.maldonado j.j.Hueso j.Cuevas Department of Agronomy University of AlmeriaceiA3 Almeria 04120Spain Experimental Station of Cajamar Las Palmerillas ceiA3 Almeria 04710Spain

Relationships between plant water status and gas exchange parameters at increasing levels of water stress were determined in Algerie loquats which grown in 50 I pots. Changes in soil water content and stem water potential and their effects on stomatal conductance （Gs ） and net photosynthesis （Pn） rate were followed in control plants and in plants without irrigation until the latter reached near permanent wilting point and some leaf abscission took place. Then, the irrigation was restarted and the comparison repeated. Soil water content and stem water potential gradually diminished in response to drought reaching the minimum values of 0.9 mm and -5.0 mPa, respectively, 9 days after watering suspension. Compromised plant water status had drastic effects on Gs values that dropped by 97％ in the last day of the drought period. Pn was diminished by 80％ at the end of the drought period. The increasing levels of water stress did not cause a steady increase in leaf temperature in non-irrigated plants. Non-irrigated plants wilted and lost some leaves due to the severity of the water stress. However, all non-irrigated plants survived and reached similar Pn than control plants just a week after the irrigation was restarted, confirming drought tolerance of loquat and suggesting that photosynthesis machinery remained intact.

关键词： Eriobotrya japonica deficit irrigation stem water potential net photosynthetic rate stomatal conductance

ON THE IDENTIFICATION OF RESIDUAL ImPACT PROPERTIES OF mATERIALS BY ACOUSTO-ULTRASONICS——A PATTERN RECOGNITION APPROACH

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Acta mechanica Sinica 1995年第1期11卷 34-43页

作者： G.j.molina Y.m.Haddad Dept.of mechanical Engineering University of OttawaOttawaCanada K1N 6N5

This paper deals with the application of Acousto-ultrasonics,in con- junction with Pattern Recognition and Classification techniques,to the identification of residual impact properties of a class of polymeric material,namely,Polyvinylchlo- ride(PVC).PVC specimens of different low-energy repeated impact damage states are processed by Acousto-ultrasonics(AU)to retrieve AU signals in the form of dig- italized *** AU signals are grouped as distinct classes,each pertaining to a known level of repeated impact *** features of these AU signals are used to build Pattern Recognition(PR)*** classifiers are used to identify unknown damage states in other PVC specimens by classifying the re- trieved AU signals as belonging to one of the *** obtained results indicate that Acousto-ultrasonics in combination with Pattern Recognition and Classification techniques can be used for the quantitative non-destructive identification of damage states in PVC specimens of unknown low-energy repeated impact conditions.

关键词： pattern recognition acousto-ultrasonics impact damage quantitative non-destructive examination

Effects of grid size on predictions of bed expansion in bubbling fluidized beds of Geldart B particles： A generalized rule for a grid-independent solution of TFm simulations

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Particuology 2017年第5期15卷 61-69页

作者： m. Helal Uddin Charles j. Coronella Department of Chemical and materials Engineering University of Nevada Reno NV 89557 USA

Numerical simulations of gas-solid fluidized beds based on the kinetic theory of granular flow exhibit a significant dependence on domain discretization. Bubble formation, bubble size and shape all vary greatly with the discretization, and the use of an inappropriate scale resolution leads to inaccurate predictions of fluidization hydrodynamics. In this study, grid-independent solutions of the two fluid model were examined by comparing the bed expansions obtained from numerical simulations with experimental results and empirical predictions, based on bubbling fluidized beds of Geldart B particles. Grid indepen- dence was achieved with a grid resolution equal to 18 times the particle diameter. The simulation results were compared with previously published data for verification purposes. The results of this work should provide a guideline for choosing the appropriate grid size and thereby minimize the time and expense associated with large simulations.

关键词： mesh effectHydrodynamicsComputational fluid dynamicsEuler-Euler method mFIX

Surface modification of stratum corneum for drug delivery and skin care by microplasma discharge treatment

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Plasma Science and Technology 2019年第6期21卷 1-8页

作者： j KRISTOF T AOSHImA m BLAjAN K SHImIZU Graduate School of Science and Technology Shizuoka University 432-8561 Hamamatsu Japan Department of Electrical and Electronic Engineering Shizuoka University 432-8561 Hamamatsu Japan Organization for Innovation and Social Collaboration Shizuoka University 432-8561 Hamamatsu Japan

Human skin is the largest organ and also the main barrier that prevents foreign substances from entering the *** surface properties of the skin are relevant for transdermal drug delivery and *** micropig skin is used as a substitute for human skin.A microplasma electrode is used for surface modification of the skin epidermal layer of the Yucatan *** dielectric barrier discharge has a thin dielectric as a barrier (~50 μm) and a frequency of 25 *** surface properties of the epidermal layer were characterized by the measurement of the contact angle of the water *** effects of different gases such as air,nitrogen,oxygen,helium or argon were *** change of the contact angle is temporal and it is returned to its initial state after several *** the gases used for plasma ignition,oxygen and argon were the most effective for skin *** distance of the skin from the electrode and the treatment time played a crucial roles in the increasing water contact *** of surface atomic concentration were determined by x-ray photoelectron *** microplasma treatment,the oxygen and nitrogen concentration increased at the skin surface.

关键词： microplasma contact angle skin stratum corneum XPS

Biological transformation,kinetics and dose-response assessments of bound musk ketone hemoglobin adducts in rainbow trout as biomarkers of environmental exposure

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journal of Environmental Sciences 2008年第7期20卷 878-884页

作者： m A mottaleb j H Zimmerman T W moy Department of Chemistry and Biochemistry Baylor UniversityP.O.Box 97348WacoTX 76798USA. U.S.Environmental Protection Agency National Exposure Research LaboratoryEnvironmental Sciences Division944 East Harmon AveLas VegasNV 89119USA

Low levels (ng/g) of musk ketone (mK),used as a fragrance additive in the formulation of personal care products,are frequently detected in the water and other ***,aquatic organisms can be continuously exposed to *** this study,kinetics and dose-response assessments of 2-amino-mK (AmK) metabolite,bound to cysteine-hemoglobin (Hb) in rainbow trout,formed by enzymatic nitro-reduction of mK have been *** were exposed to a single exposure of 0.010,0.030,0.10,and 0.30 mg mK/g ***...

关键词： biotransformation kinetics hemoglobin adducts dose-response nitro musks biomarker fish