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Approximation Properties of Vectorial Exponential Functions

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Communications on Applied Mathematics and Computation 2024年第3期6卷 1801-1831页

作者： Christophe buet Bruno Despres Guillaume Morel CEA DAMDIF91297 ArpajonFrance Laboratoire en Informatique Haute Performance Pour le Calcul et la Simulation CEAUniversitéParis-Saclay91680 Bruyeres-le-ChatelFrance Laboratoire Jacques-Louis Lions UMR 7598Sorbonne Universite75005 ParisFrance IMT Atlantique 29238 BrestFrance

This contribution is dedicated to the celebration of Rémi Abgrall’s accomplishments in Applied Mathematics and Scientific Computing during the conference“Essentially Hyperbolic Problems:Unconventional Numerics,and Applications”.With respect to classical Finite Elements Methods,Trefftz methods are unconventional methods because of the way the basis functions are *** discontinuous Galerkin(TDG)methods have recently shown potential for numerical approximation of transport equations[6,26]with vectorial exponential *** paper focuses on a proof of the approximation properties of these exponential *** show that vectorial exponential functions can achieve high order *** fundamental part of the proof consists in proving that a certain rectangular matrix has maximal rank.

关键词： Trefftz method Transport equation Vectorial exponential functions

Effect of Recycling Cycles on the Mechanical and Damping Properties of Short Alfa Fibre Reinforced Polypropylene Composite

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Journal of Renewable Materials 2019年第3期7卷 253-267页

作者： Fatima Ezzahra El Abbassi Mustapha Assarar Rezak Ayad Hamid Sabhi stephane buet Nouzha Lamdouar Department of Civil Engineering University of Cadi AyyadMorocco Laboratory of Engineering and Material Sciences University of Reims Champagne-ArdenneFrance Laboratory of Simulation Instrumentation and MeasurementUniversity of Mohammed VMorocco

This paper aims at studying the effect of recycling on the static and dynamic properties of short alfa fibre reinforced *** this purpose,alfa fibres reinforced composites were elaborated by an injection moulding process and were subjected to different mechanical recycling ***,non-recycled and recycled materials were subjected to static tests and Dynamic Mechanical Analysis(DMA)to evaluate the effect of recycling on their ***,the effects of alkali and salt water treatments on the static and dynamic properties of the alfa composite were also *** obtained results show that tensile and flexural properties of alfa fibres reinforced composites decrease during recycling ***,the recycling induces a drop in the storage modulus and enhances the loss factor of these *** composites with alfa fibre especially the alkali treated composite show the same resistance to recycling as composites with hemp ***,SEM observations indicate a decrease in the fibres dimension with the recycling cycles,especially for alfa fibres,which can explain the decrease in the properties of the alfa composite during recycling operations.

关键词： Alfa fibre hemp fibre eco-composites recycling mechanical properties dynamic properties

A Multinomial Theorem for Hermite Polynomials and Financial Applications

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Applied Mathematics 2015年第6期6卷 1017-1030页

作者： Francois buet-Golfouse Department of Mathematics Ecole Normale Superieure de Cachan Cachan France

Different aspects of mathematical finance benefit from the use Hermite polynomials, and this is particularly the case where risk drivers have a Gaussian distribution. They support quick analytical methods which are computationally less cumbersome than a full-fledged Monte Carlo framework, both for pricing and risk management purposes. In this paper, we review key properties of Hermite polynomials before moving on to a multinomial expansion formula for Hermite polynomials, which is proved using basic methods and corrects a formulation that appeared before in the financial literature. We then use it to give a trivial proof of the Mehler formula. Finally, we apply it to no arbitrage pricing in a multi-factor model and determine the empirical futures price law of any linear combination of the underlying factors.

关键词： Hermite Polynomials Multi-Factor Model Hilbert Space Mehler Formula

Numerical Prediction of Fluid Flow and Heat Transfer in a Wavy Pipe

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Journal of Thermal Science 2001年第2期10卷 133-138,147页

作者： Shohel Mahmud A.K.M. Sadrul Islam Prodip Kumar Das Department of Mechanical Engineering, Bangladesh University of Engineering & Technology, buet, Dhaka-1000, Bangladesh Department of Mechanical Engineering Bangladesh University of Engineering & Technology BUET Dhaka Bangladesh

Hydrodynamic and thermal characteristics in a pipe with sinusoidal wavy surface for steady laminar flow are invdtigted numerically in the present study. The integral forms of governing equations are discretized using control volume based Finite Volume method with collocated variable arrangement, SIMPLE algorithm is used and TDMA solver is applied for solution of system of equations. A pipe of length equal to 4λ is considered. Effect of surface waviness, determined by wavelength-amplitude ratio λ/a (=L), on flow and thermal field is presented. The simulation work has been carried out for L’=11.0 -30.0 for a Reynolds number range50 to 2000. Results are presented in the form of streamfunction, isothermal lines, velocity and vorticity profiles, change of mean friction factor, variation in skin fiction. local and average Nusselt number with Reynolds number, wave number (n) and L’. For a particular geometry. length of circulation zone increases with Reynolds number and approaches a limiting value for higher Reynolds number. Wall shear stress in the bulge part of the chancel shows smaller values that affect largely the be of heat transfer and Nusselt number shows minimum values in this region. This circulation zone drastically increases with the increase of surface waviness showing high mean friction factor per wavelength. Mean friction factor inversely varies with Reynolds number. A correlation is proposed for calculating friction factor in the form f=C/(Re)m, where ’C and ’m’ represents two polynomials of degree 4 and 2 respectively and are function of L. Higher waviness of the surface shows the higher heat transfer rate than lower waviness. Heat transfer rate falls almost exponentially along the axial direction with the increase of wave number.

关键词： Nusselt number separation bubble surface wavomess wall vorticity

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Natural Convection Heat Transfer From a Hot Rectangular and a Square Corrugated Plate to a Cold Flat Plate

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Journal of Thermal Science 2000年第3期9卷 243-248页

作者： M. A. R. Akhanda F. M. Chowdhury (Department of Mechanical Engineering, Bangladesh University of Engineering and Technology (buet), Dhaka- 1000, Bangladesh) Department of Mechanical Engineering Bangladesh University of Engineering and Technology (BUET) Bangladesh

Experimental study of natural convection heat transfer across air layers bounded by a lower hot rectangular and a square corrugated plates to an upper cold flat plate has been carried out. The surroundings of this space are adiabatic. The effect of the angle of inclination, the aspect ratio, the temperature potential and the Rayleigh number on average heat transfer coefficients are investigated within a range of 0°≤75°,, 2.33≤A≤6.33, 10°≤T ≤35°, and 3.29xl04≤RaL≤ 2.29x106. The developed correlation predicts well the experimental data within an error of ±15%.

关键词： natural convection heat transfer corrugation.

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Clinical significance of the loss of CD20 antigen on tumor cells in patients with relapsed or refractory follicular lymphoma

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Cancer Drug Resistance 2021年第3期4卷 710-718页

作者： Jean-Marie Michot Alice buet-Elfassy Maxime Annereau Julien Lazarovici Alina Danu Clémentine Sarkozy Claude Chahine Camille Bigenwald Jacques Bosq Julien Rossignol Patricia Romano-Martin Capucine Baldini David Ghez Peggy Dartigues Christophe Massard Vincent Ribrag Gustave Roussy UniversitéParis-SaclayDépartement des Innovations Thérapeutiques et Essais PrécocesVillejuif 94800France Gustave Roussy UniversitéParis-SaclayPharmacy DepartementVillejuif 94800France Gustave Roussy UniversitéParis-SaclayDepartement of HematologyVillejuif 94800France Gustave Roussy UniversitéParis-SaclayDepartement of PathologyVillejuif 94800France

Aim:Anti-CD20 monoclonal antibody is a cornerstone therapy for follicular *** anti-CD20 therapy,a potential decrease in CD20 antigen,and therefore a loss of the tumor target might be ***,the incidence and clinical significance of CD20 loss on tumor cells in patients with relapsed or refractory follicular lymphoma are *** study aims to investigate the incidence and outcome of patients with relapsed or refractory follicular lymphoma patients harboring the loss of the tumor target,***:All consecutive adult patients with relapsed or refractory follicular lymphoma referred to the Early Drug Department at Gustave Roussy were *** main objectives were to assess the incidence and prognosis of the loss in expression of CD20 antigen on the surface of tumor cells on patient ***:Over the study period 2013-2018,131 patients were screened for clinical trials with B-cell malignancies in the early drug department of Gustave Roussy in ***-four patients presented with relapsed or refractory follicular lymphoma and 32 had tumor biopsies at the time of relapse that were retained for *** median(range)age was 67.5 years(55.3-75.3)and the median number of prior anti-cancer systemic therapies was 3(2-4).At the time of relapse,CD20 expression was positive in 84%of tumors(n=27)and negative in 16%of tumors(n=5).At a median follow-up of 18.3(0.6-83.3)months,CD20 negativity was associated with a poorer prognosis with a median overall survival of 8.9 months(95%CI:2.4-19.1)in comparison to CD20 positive patients(28.3 months,95%CI:25.1-75.3 months,P=0.019).Conclusion:The loss of the tumor target antigen,CD20,occurred in 16%of patients with relapse or refractory follicular *** to confounding factors in patients who received anti-CD20 immunotherapy,it was not possible to formally establish the prognostic significance of CD20 ***,we suggest that a check for CD20 antigen positivity nevertheless

关键词： Follicular lymphoma CD20 tumor antigen anti-CD20 monoclonal antibody cancer drug resistance

LOCAL SCOUR EstIMATION AT BRIDGE SITE: MODIFICATION AND APPLICATION OF LACEY FORMULA

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International Journal of Sediment Research 2003年第4期18卷 333-339页

作者： Md. Munsur RAHMAN,iwfm.buet.ac.bd at present: Post Doctoral Research fellow, Ujigawa Open Laboratory, Disaster Prevention Research Institute, Kyoto University, Shimomisu, Yoko-Oji, Fushimi-Ku, Kyoto 612-8235, Japan ,M. Anisul HAQUE Assistant Professor Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (buet) Dhaka-1000 Bangladesh E-mail: mmrahman Associate Professor Institute of Water and Flood Management (IWFM) Bangladesh University of Engineering and Technology (buet) Dhaka-1000 Bangladesh

In the recent years, it has been established that b/h or h/b (b = length of the structure in the lateral direction and h = approach flow depth) is the dominant factor for the estimation of local scour depth around abutments and piers. One of the major limitations of the Lacey formula is that it predicts only one value of the scour depth for a specific river because of the absence of important parameters b and h. Therefore, its application is quite uncertain for variable b and h. Considering its limitations and experimental facts of flow concentration and shear stress amplification close to above structures, the original Lacey formula is modified introducing the parameters b and h. The applicability of the original as well as modified Lacey formula is tested to the data collected from major rivers in Bangladesh.

关键词： Local scour depth Piers and abutments Lacey formula Bangladesh

EXPERIMENTAL stUDY ON SEDIMENT DIstRIBUTION AT CHANNEL BIFURCATION

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International Journal of Sediment Research 2002年第2期17卷 124-136页

作者： G.M. Tarekul ISLAM1, M.R. KABIR2 and Ainun NISHAT3 1 Institute of Flood Control and Drainage Research, Bangladesh University of Engineering and Technology, Dhaka 1000, Bangladesh, E-mail: tarek@ifcdr.buet.ac.bd 2 Department of Water Resources Engineeri Institute of Flood Control and Drainage Research Bangladesh University of Engineering and Technology Dhaka 1000 Bangladesh Department of Water Resources Engineering Bangladesh University of Engineering and Technology Dhaka 1000 Bangladesh International Union for Conservation of Nature Dhaka Bangladesh

This paper presents the experimental results on the distribution of sediments at channel bifurcation. The experiments have been conducted in a physical model of channel bifurcation. It consists of a straight main channel which bifurcates into two branch channels of different widths. The test rig is a mobile bed with fixed bank. Four different noses have been used to study the phenomenon. For each nose, three upstream discharges viz. 20 l/s, 30 l/s and 40 l/s have been employed. From the measured data, discharges and sediment transport ratios per unit width are calculated in the downstream branches. These data have been set to the general nodal point relation and a set of equations has been developed to describe the distribution of sediments to the downstream branches for different nose angles.

关键词： Bifurcation Distribution of sediment Nose angle Nodal point relation