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Energy dissipation on stepped spillways and hydraulic challenges—Prototype and laboratory experiences

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Journal of Hydrodynamics 2022年第1期34卷 52-62页

作者： hubert Chanson School of Civil Engineering The University of QueenslandBrisbaneAustralia

Stepped cascades, chutes and spillways have been in use for more than three millennia. With the introduction of new construction materials and techniques, the staircase chute design has regained some interest within the last forty years. The stepped invert increases significantly the energy dissipation occurring above the steep chute and reduces the size of the required downstream stilling structure. The application of stepped chutes further encompasses in-stream re-aeration and water treatment plant cascades, to enhance the air-water transfer of atmospheric gases and of volatile organic components. However, the engineering design of stepped spillways is not simple because of the hydrodynamic challenges, with several markedly different flow regimes, some complicated two-phase air-water fluid dynamics and massive rate of energy dissipation above the stepped chute. Simply, the technical challenges in the hydraulic design of stepped spillways are massive. This review paper examines the hydraulic characteristics of stepped chute flows and develops a reflection on nearly three decades of active hydraulic research, including recent field measurements during major flood events. The author aims to share his passion for the complicated hydraulic engineering, as well as some advice for engineering professionals and researchers.

关键词： Stepped spillways hydraulic modeling field measurements energy dissipation and design multiphase air-water flows

Deterministic Homogenization of Nonlinear Degenerate Elliptic Operators with Nonstandard Growth

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Acta Mathematica Sinica,English Series 2014年第9期30卷 1621-1654页

作者： hubert NNANG University of Yaounde I Ecole Normale Suprieure de Yaound

We study the deterministic homogenization of nonlinear degenerate elliptic equations with nonstandard growth. One fundamental in this topic is to extend the classical compactness results of the E-convergence method to the Orlicz spaces. We also show that one can homogenize nonlinear Dirichlet problems in a general way by leaning on a simple abstract hypothesis contrary to what has been done in the determinstic homogenization theory.

关键词： Determinstic homogenization degenerate operator H-algebras Orlicz-Sobolev spaces

Bubble entrainment, spray and splashing at hydraulic jumps

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2006年第8期7卷 1396-1405页

作者： CHANSON hubert Division of Civil Engineering The University of Queensland Brisbane QLD 4072 Australia

The sudden transition from a high-velocity, supercritical open channel flow into a slow-moving sub-critical flow is a hydraulic jump. Such a flow is characterised by a sudden rise of the free-surface, with some strong energy dissipation and air entrainment, waves and spray. New two-phase flow measurements were performed in the developing flow region using a large-size facility operating at large Reynolds numbers. The experimental results demonstrated the complexity of the flow with a developing mixing layer in which entrained bubbles are advected in a high shear stress flow. The relationship between bubble count rates and void fractions was non-unique in the shear zone, supporting earlier observations of some form of double diffusion process between momentum and air bubbles. In the upper region, the flow consisted primarily of water drops and packets sur-rounded by air. Visually significant pray and splashing were significant above the jump roller. The present study is the first com-prehensive study detailing the two-phase flow properties of both the bubbly and spray regions of hydraulic jumps, a first step towards understanding the interactions between bubble entrainment and droplet ejection processes.

关键词： Hydraulic jump Air bubble entrainment Spray and splashing physical modelling Particle chord time distributions

Two-phase air-water flows: Scale effects in physical modeling

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Journal of Hydrodynamics 2014年第2期26卷 291-298页

作者： PFISTER Michael CHANSON hubert Ecole Polytechnique Fédérale de Lausanne (EPFL) Laboratory of Hydraulic Constructions (LCH) The University of Queensland School of Civil Engineering

Physical modeling represents probably the oldest design tool in hydraulic engineering together with analytical approaches. In free surface flows, the similitude based upon a Froude similarity allows for a correct representation of the dominant forces, namely gravity and inertia. As a result fluid flow properties such as the capillary forces and the viscous forces might be incorrectly reproduced, affecting the air entrainment and transport capacity of a high-speed model flow. Small physical models operating under a Froude similitude systematically underestimate the air entrainment rate and air-water interfacial properties. To limit scale effects, minimal values of Reynolds or Weber number have to be respected. The present article summarizes the physical background of such limitations and their combination in terms of the Morton number. Based upon a literature review, the existing limits are presented and discussed, resulting in a series of more conservative recommendations in terms of air concentration scaling. For other air-water flow parameters, the selection of the criteria to assess scale effects is critical because some parameters （e.g., bubble sizes, turbulent scales） can be affected by scale effects, even in relatively large laboratory models.

关键词： air entrainment hydraulic structures physical modeling scale effects two-phase flow Morton number

Hepatocellular carcinoma: Therapy and prevention

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World Journal of Gastroenterology 2005年第47期11卷 7391-7400页

作者： hubert E Blum Department of Medicine Ⅱ University of FreiburgD-79106 FreiburgGermany

Hepatocellular carcinoma (HCC) is one of the most common malignant tumors worldwide. The major etiologies and risk factors for the development of HCC are well defined and some of the multiple steps involved in hepatocarcinogenesis have been elucidated in recent years. Despite these scientific advances and the implementation of measures for the early detection of HCC in patients at risk, patient survival has not improved during the last three decades. This is due to the advanced stage of the disease at the time of clinical presentation and limited therapeutic options. The therapeutic options fall into five main categories: surgical interventions including tumor resection and liver transplantation, percutaneous interventions including ethanol injection and radiofrequency thermal ablation, transarterial interventions including embolization and chemoembolization, radiation therapy and drugs as well as gene and immune therapies. These therapeutic strategies have been evaluated in part in randomized controlled clinical trials that are the basis for therapeutic recommendations. Though surgery, percutaneous and transarterial interventions are effective in patients with limited disease (1-3 lesions, ＜5 cm in diameter) and compensated underlying liver disease (cirrhosis Child A), at the time of diagnosis more than 80% patients present with multicentric HCC and advanced liver disease or comorbidities that restrict the therapeutic measures to best supportive care. In order to reduce the morbidity and mortality of HCC, early diagnosis and the development of novel systemic therapies for advanced disease, including drugs, gene and immune therapies as well as primary HCC prevention are of paramount importance. Furthermore, secondary HCC prevention after successful therapeutic interventions needs to be improved in order to make an impact on the survival of patients with HCC. New technologies, including gene expression profiling and proteomic analyses, should allow to further elucida

关键词： HCC resection Liver transplantation Percutaneous ethanol injection Radiofrequency thermal ablation Transarterial embolization or chemoembolization Chemotherapy Gene therapy Immune therapy Prevention

Diagnosing Battery Degradation via Gas Analysis

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Energy & Environmental Materials 2022年第3期5卷 688-692页

作者： Michael Metzger hubert A.Gasteiger Department of Physics and Atmospheric Science Dalhousie UniversityHalifax Nova Scotia B3H 4R2Canada Department of Chemistry Dalhousie UniversityHalifax Nova Scotia B3H 4R2Canada Chair of Technical Electrochemistry Department of Chemistry and Catalysis Research CenterTechnical University of MunichD-85748Garching Germany

Interfacial reactions in lithium-ion batteries often involve gaseous reaction *** investigation of material degradation processes requires a technique to identify and quantify these gases in battery *** electrochemical mass spectrometry(OEMS)is an operando gas analysis method that continuously samples the headspace of a custom battery ***-time gas analysis by quantitative OEMS was used to create mechanistic understanding of battery degradation reactions,some of which will be highlight in this article.

关键词： aging mechanisms batteries energy storage gas analysis in situ and operando characterization

Influence of irritable bowel syndrome on treatment outcome in gastroesophageal reflux disease

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World Journal of Gastroenterology 2011年第27期17卷 3235-3241页

作者： hubert Mnnikes Robert C Heading Holger Schmitt hubert Doerfler Department of Medicine Martin-Luther HospitalAcademic Teaching Hospital of CharitéUniversitts-medizin14193 BerlinGermany Edinburgh EH10 7ARScotlandUnited Kingdom Nycomed GmbH 78467 ConstanceGermany Nycomed International Management GmbH 8152 ZurichSwitzerland

AIM: To investigate the influence of irritable bowel syndrome (IBS)-like symptoms on treatment outcomes with pantoprazole in gastroesophageal reflux disease (GERD) in a real life setting. METHODS: For this prospective, open-label, multinational, multicentre study, 1888 patients assessed by the investigators as suffering from GERD were recruited. The patients were additionally classified as with or without IBS-like symptoms at baseline. They were treated with pantoprazole 40 mg once daily and completed the Reflux Questionnaire (ReQuest) short version daily. Response rates and symptom scores were compared after 4 and 8 wk of treatment for subgroups defined by the subclasses of GERD [erosive(ERD) and non-erosive reflux disease (NERD)] and the presence of IBS-like symptoms. RESULTS: IBS-like symptoms were more prevalent in NERD than in ERD (18.3% vs 12.7%, P = 0.0015). Response rates after 4 and/or 8 wk of treatment were lower in patients with IBS-like symptoms than in patients without IBS-like symptoms in both ERD (Week 4: P < 0.0001, Week 8: P < 0.0339) and NERD (Week 8: P = 0.0088). At baseline, ReQuest "lower abdominal com- plaints" symptom scores were highest in NERD patients with IBS-like symptoms. Additionally, these patients had the strongest symptom improvement after treatment compared with all other subgroups. CONCLUSION: IBS-like symptoms influence treatment outcome and symptom burden in GERD and should be considered in management. Proton pump inhibitors can improve IBS-like symptoms, particularly in NERD.

关键词： Pantoprazole ReQuestTM Clinical practice Irritable bowel syndrome Gastroesophageal reflux disease

Vacuum Furnace - Integrated“Sub zero” Treatment

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材料热处理学报 2004年第5期25卷 588-590页

作者： B. Zieger hubert Schulte SCHMETZ GmbH Menden GermanySCHMETZ GmbH Menden Germany

The vacuum heat treatment with overpressure gas quenching is more and more accepted due to considerable advantages compared to the traditional oil and salt bath processes. Continuous further developments and new concepts like multi-directional cooling systems, a separate quenching chamber and "sub zero" systems lead towards an oxidation free and low distortion vacuum heat treatment for a broad range of parts and materials. Short and energy saving processes guarantee a high economic efficiency and environmental compatibility. The "sub zero" system which is integrated into the standard vacuum furnace achieves a heat treatment result with a high conversion of retained austenite in fully automatic hardening and tempering processes.

关键词：真空炉真空热处理深度冷冻过压气体流淬火

The Plastics Industry:Worldwide and European Overview

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塑料工业 2013年第S1期41卷 34-52页

作者： hubert SIMON ISO/TC(Plastics)