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Contribution of Fluid Dynamics to Woodwind Instruments Investigations of Timbre and Pitch of Bassoon Bocals

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Journal of Thermal Science 2005年第3期14卷 264-266页

作者： roger GRUNDMANN Johannes BAUMGART Andreas RICHTER Hans KRüGER Technische Universitt Dresden Institute for Aerospace Engineering D-01062 Dresden Germany ProfessorTechnische Universitt Dresden Institute for Aerospace Engineering D-01062 Dresden GermanyTechnische Universitt Dresden Institute for Aerospace Engineering D-01062 Dresden GermanyTechnische Universit?t Dresden Institute for Aerospace Engineering D-01062 Dresden Germany

The discussed topic of isolating certain parameters which describe the timbre in connection with bocals of bassoons is of major interest for manufacturers and artist likewise since a reduction in the overall shear stress of these kinds of technical diffusors is very helpful but not sufficient. The timbre seen from the side of the musician has to be the same. Up to now two criteria have been isolated which have a deep influence on the easier blowing of the bassoon and on the comparable timbre due to geometrical reasons. If the geometrical outer contour is designed carefully, it is possible to modify the shape and preserve the timbre.

关键词： musical instrument bocal bassoon timbre principal component analysis

Two-step fast microwave-assisted pyrolysis of biomass for bio-oil production using microwave absorbent and HZSM-5 catalyst

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Journal of Environmental Sciences 2016年第7期28卷 240-247页

作者： Bo Zhang Zhaoping Zhong Qinglong Xie Shiyu Liu roger Ruan Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education Southeast University Center for Biorefining and Department of Bioproducts and Biosystems Engineering University of Minnesota

A novel technology of two-step fast microwave-assisted pyrolysis（f MAP） of corn stover for bio-oil production was investigated in the presence of microwave absorbent（Si C） and HZSM-5catalyst. Effects of f MAP temperature and catalyst-to-biomass ratio on bio-oil yield and chemical components were examined. The results showed that this technology, employing microwave, microwave absorbent and HZSM-5 catalyst, was effective and promising for biomass fast pyrolysis. The f MAP temperature of 500°C was considered the optimum condition for maximum yield and best quality of bio-oil. Besides, the bio-oil yield decreased linearly and the chemical components in bio-oil were improved sequentially with the increase of catalyst-to-biomass ratio from 1：100 to 1：20. The elemental compositions of bio-char were also determined. Additionally, compared to one-step f MAP process, two-step f MAP could promote the bio-oil quality with a smaller catalyst-to-biomass ratio.

关键词： Two-step Microwave Pyrolysis HZSM-5 zeolite catalyst Catalytic upgrading

Skyline-join query processing in distributed databases

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Frontiers of Computer Science 2016年第2期10卷 330-352页

作者： Mei BAI Junchang XIN Guoren WANG roger ZIMMERMANN Xite WANG College of Information Science and Engineering Northeastern University Shenyang 110819 China School of Computing National University of Singapore Singapore 117417 Singapore

The skyline-join operator, as an important variant of skylines, plays an important role in multi-criteria decision making problems. However, as the data scale increases, previous methods of skyline-join queries cannot be applied to new applications. Therefore, in this paper, it is the first attempt to propose a scalable method to process skyline-join queries in distributed databases. First, a tailored distributed framework is presented to facilitate the computation of skyline-join queries. Second, the distributed skyline-join query algorithm （DSJQ） is designed to process skyline-join queries. DSJQ contains two phases. In the first phase, two filtering strategies are used to filter out unpromising tuples from the original tables. The remaining tuples are transmitted to the corresponding data nodes according a partition function, which can guarantee that the tuples with the same join value are transferred to the same node. In the second phase, we design a scheduling plan based on rotations to calculate the final skyline-join result. The scheduling plan can ensure that calculations are equally assigned to all the data nodes, and the calculations on each data node can be processed in parallel without creating a bottleneck node. Finally, the effectiveness of DSJQ is evaluated through a series of experiments.

关键词： skyline-join distributed filtering strategy scheduling plan rotation

Rotational Forms of Large Eddy Simulation Turbulence Models:Modeling and Mathematical Theory

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Chinese Annals of Mathematics,Series B 2021年第1期42卷 17-40页

作者： Luigi C.BERSELLI roger LEWANDOWSKI Dinh Duong NGUYEN Universita di Pisa Dipartimento di MatematicaVia Buonarroti 1/c1-56127 Pisa Italy IRMAR UMR CNRS 6625University of Rennes 1 and FLUMINANCE TeamINRIA RennesFrance

In this paper the authors present a derivation of a back-scatter rotational Large Eddy Simulation model,which is the extension of the Baldwin&Lomax model to nonequilibrium *** model is particularly designed to mathematically describe a fluid filling a domain with solid walls and consequently the differential operators appearing in the smoothing terms are degenerate at the *** the derivation of the model,the authors prove some of the mathematical properties coming from the weighted energy estimates,which allow to prove existence and uniqueness of a class of regular weak solutions.

关键词： Fluid mechanics Turbulence models Rotational Large Eddy Simulation models Navier-Stokes equations

Reduction of NO by CO using Pd–CeTb and Pd–CeZr catalysts supported on SiO_2 and La_2O_3–Al_2O_3

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Journal of Environmental Sciences 2015年第1期27卷 87-96页

作者： Victor Ferrer Dora Finol roger Solano Alexander Moronta Miguel Ramos Instituto de Superficies y Catálisis Facultad de Ingeniería Universidad del Zulia Instituto Zuliano de Investigaciones Tecnológicas km 15 carretera Vía a la Ca?ada Apartado 331 Venezuela

The catalytic activity of Pd catalysts supported on Ce0.73Tb0.27Ox/SiO2, Ce0.6Zr0.4Ox/Si O2,Ce0.73Tb0.27Ox/La2O3–Al2O3and Ce0.6Zr0.4Ox/La2O3–Al2O3was studied using the reduction of NO by CO. The catalysts were characterized by X-ray fluorescence, surface area, X-ray diffraction, temperature-programmed reduction, CO chemisorption and oxygen storage capacity. Temperature-programmed reduction results indicated that Tb or Zr incorporation improves the reducibility and oxygen storage capacity. CO chemisorption data suggested the presence of large Pd O particles due to the low CO/Pd ratio. No significant differences were obtained in light off temperatures（T Light off） for all Pd catalysts and the most active was1.5%Pd/Ce0.6Zr0.4Ox/SiO2.

关键词： Mixed oxides OSC Reduction of NO by CO Three way catalysts

Dual targeting nano-approaches for Alzheimer’s disease etiology

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Neural Regeneration Research 2021年第1期16卷 119-120页

作者： Sajini D.Hettiarachchi roger M.Leblanc Department of Chemistry University of Miami Coral GablesFLUSA

Alzheimer’s disease(AD)is the most common progressive neurodegenerative disorder of *** characteristic features of AD begin as mild cognitive dysfunctions,which gradually progress to the fatal delirium through a total loss of cognition and executive motor functions(Pimplikar et al.,2010).Three decades later from now,more than 100 million people will suffer from AD worldwide by making it the most expensive disease(Prince et al.,2013;Bloom,2014).The major pathological hallmarks of the AD is the extracellular amyloid-beta(Aβ)plaques deposition and the intracellular neurofibrillary tangle-aggregation of hyperphosphorylated *** the fact that Aβand tau-phosphorylation is the primary etiology for the AD,the recent concern developed on anti-amyloid mechanisms,such as cholinergic dysfunction and reactive oxygen species(ROS)*** current most prevalent clinical arena is,treating amyloid or non-amyloid hypothesis ***,the intercorrelated nature of amyloid and non-amyloid hypothesis governs the need of the intervention of combined diagnostic approaches.

关键词： Alzheimer spite aggregation

Measurements of coupled fluid and sediment motion over mobile sand dunes in a laboratory flume

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International Journal of Sediment Research 2008年第4期23卷 329-337页

作者： Daniel G.WREN roger A.KUHNLE Research Hydraulic Engineer USD A-ARS-National Sedimentation LaboratoryPh.D Research Hydraulic Engineer USD A-ARS-National Sedimentation Laboratory

The relationship between turbulent fluid motions and sediment particle motions over mobile sand dunes was investigated by using a laser Doppler velocimeter and an acoustic backscatter system in laboratory experiments performed at the USDA-ARS-National Sedimentation Laboratory. Profiles of acoustic backscatter from particles and at-a-point turbulence data were collected while translating both measurement devices downstream at the speed of mobile dune bedforms. The resulting data set was used to examine the frequency (recurrence frequency) at which the fluctuating backscatter and fluid velocity signals exceeded magnitude thresholds based on the standard deviation (σ) of the local velocity and the magnitude the acoustic signal resulting from backscatter from suspended particles. The slope of the downstream and vertical velocity recurrence frequencies generally indicated a gradually increasing recurrence time with increasing elevation. The recurrence frequency for acoustic backscatter data was not strongly variable with elevation. The closest correspondence between the recurrence frequencies of sediment backscatter and vertical velocities at the 1σ magnitude threshold was in a region defined by X/L<0.4 and y<6 cm. The downstream velocity was most closely related to backscatter in a small region at 0.4

关键词： Turbulence Suspended sediment Acoustic backscatter Dunes

Xom interacts with and stimulates transcriptional activity of LEFI/TCFs: implications for ventral cell fate determination during vertebrate embryogenesis

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Cell Research 2007年第4期 345-356页

作者： roger Giese Boston USA Department of Pharmaceutical Sciences Northeastern University MA

LEF1/TCFs are high mobility group box-containing transcriptional factors mediating canonical Wnt/β-catenin sig-naling during early embryogenesis and tumorigenesis.β-Catenin forms a complex with LEF1/TCFs and transactivatesLEF1/TCF-mediated transcriptions during *** LEF-mediated transcription is also implicated inventralization,the underlying molecular mechanism is not well *** the vertebrate Xenopus Iaevis modelsystem,we found that Xom,which is a ventralizing homeobox protein with dual roles of transcriptional activation andrepression,forms a complex with LEF 1/TCF through its homeodomain and transactivates LEF 1/TCF-mediated transcrip-tion through its N-terminal transactivation domain(TAD).Our data show that Xom lacking the N-terminal TAD failsto transactivate ventral genes,such as BMP4 and Xom itself,but retains the ability to suppress transcriptional activationof dorsal gene promoters,such as the Goosecoid promoter,indicating that transactivation and repression are separablefunctions of *** has been postulated that Xom forms a positive re-enforcement loop with BMP4 to promote ventral-ization and to suppress dorsal gene *** with an essential role of Xom transactivation of LEF1/TCFsduring early embryogenesis,we found that expression of the dominant-negative Xom mutant that lacks the TAD fails tore-enforce the ventral signaling of BMP4 and causes a catastrophic effect during *** data suggest that thefunctional interaction of Xom and LEF 1/TCF-factors is essential for ventral cell fate determination and that LEF1/TCFfactors may function as a point of convergence to mediate the combined signaling of Wnt/β-catenin and BMP4/Xompathways during early embryogenesis.

关键词： Xom Vent Wnt BMP4 β-catenin LEF1/TCFs dorsoventral patterning

Transition from wavelets to ripples in a laboratory flume with a diverging channel

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International Journal of Sediment Research 2008年第1期23卷 1-12页

作者： William B. RAUEN roger A. FALCONER Hydro-environmental Research Centre School of Engineering Cardiff University

An experimental investigation on the initiation and development of bed forms on a bed of fine silica sand was conducted under alluvial flow conditions in a laboratory flume with a diverging channel. The main aims of the study were to assess: i) the steepness of bed forms in the transition stage of development; and ii) the threshold height of wavelets (ηt) that triggered the start of ripple development. Detailed bed profile measurements were carried out using an acoustic Doppler probe, traversed longitudinally over the sediment bed at various experimentation times. The bed form dimensions were extracted from such bed profile records and analysed for the wavelet, transition and equilibrium stages. It was found that the steepness of ripples in the transition and equilibrium stages were similar, confirming predictions of previous mathematical model simulations. A lognormal distribution fitted the wavelet length data. The wavelet threshold height was estimated as ηt≈ 7 mm, or y+ ≈ 80 in wall units. Such a height magnitude suggested that ripple development could be triggered by the wavelets reaching the outer flow zone of a turbulent boundary layer. The ηt value obtained corresponded generally to the intersection point between two predictive equations for bed form dimensions. A formulation was developed to predict ηt as a function of the sediment grain size, which was confirmed for the fine sand used in this study.

关键词： Bed form Bed ripple Doppler sonar Scale model Wave height Wavelength