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A kinetic model for a single step biodiesel production from a high free fatty acid (FFA) biodiesel feedstock over a solid heteropolyacid catalyst

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Green Energy & Environment 2019年第3期4卷 328-341页

作者： Aashish Gaurav Stéphane Dumas Chau t.Q.Mai Flora t.t.Ng Department of Chemical Engineering University of Waterloo

Production of biodiesel from yellow grease(waste cooking oil and waste animal fats) is fast emerging as a promising alternative to address the twin challenges before the biodiesel industry today-fluctuation in prices of vegetable oil and the food versus fuel debate. Yellow grease has a high percentage of free fatty acids(FFA) and proves to be an unsuitable feedstock for biodiesel production from commercially viable alkalicatalyzed production systems due to saponification problems.'Green' methodologies based on heterogeneous solid acid catalyzed reactions have the potential to simultaneously promote esterification and transesterification reactions of yellow grease to produce biodiesel without soap formation and offer easy catalyst separation without generation of toxic streams. this paper presents kinetic studies for the conversion of model yellow grease feeds to biodiesel using a heteropolyacid supported on alumina(HSiW/Al2O3) using a batch autoclave. three model yellow grease feeds were prepared using canola oil with added FFA such as palmitic, oleic and linoleic acid. A pseudo homogeneous kinetic model for the parallel esterification and transesterification was developed. the rate constants and activation parameters for esterification and transesterification reactions for the model yellow grease feeds were determined. the rate constants for esterification are higher than the transesterification rate constants. the kinetic model was validated using the experimental biodiesel data obtained from processing a commercial yellow grease feed. the kinetic model could be used to design novel processes to convert various low-value waste oils, fats and non-food grade oils to sustainable biodiesel.

关键词： Yellow grease Canola oil Free fatty acids Heteropolyacid Kinetics for esterification and transesterification

Breather solutions of modified Benjamin-Bona-Mahony equation

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Chinese Physics B 2021年第2期30卷 220-226页

作者： G t Adamashvili technical University of Georgia Kostava Street 77Tbilisi0179Georgia

New two-component vector breather solution of the modified Benjamin-Bona-Mahony(MBBM)equation is *** the generalized perturbation reduction method,the MBBM equation is reduced to the coupled nonlinear Schr¨odinger equations for auxiliary *** analytical expressions for the profile and parameters of the vector breather oscillating with the sum and difference of the frequencies and wavenumbers are *** two-component vector breather and single-component scalar breather of the MBBM equation is compared.

关键词： modified Benjamin-Bona-Mahony equation generalized perturbation reduction method vector breather nonlinear waves

Real-time per-pixel focusing method for light field rendering

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Computational Visual Media 2021年第3期7卷 319-333页

作者： t.Chlubna t.Milet P.Zemcík Faculty of Information technology Brno University of Technology61200 BrnoCzech Republic

Light field rendering is an image-based rendering method that does not use 3 D models but only images of the scene as input to render new *** field approximation,represented as a set of images,suffers from so-called refocusing artifacts due to different depth values of the pixels in the *** information about depths in the scene,proper focusing of the light field scene is limited to a single focusing *** correct focusing method is addressed in this work and a real-time solution is proposed for focusing of light field scenes,based on statistical analysis of the pixel values contributing to the final *** existing techniques,this method does not need precomputed or acquired depth *** requirements and streaming bandwidth are reduced and real-time rendering is possible even for high resolution light field data,yielding visually satisfactory *** evaluation of the proposed method,implemented on a GPU,is presented in this paper.

关键词： image-based rendering light field plenoptic function computational photography

Prediction model for the diffusion length in silicon-based solar cells

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Journal of Semiconductors 2009年第7期30卷 3-6页

作者： Cheknane A Benouaz t Laboratoire d'Etude et Dveloppement des Matriaux Semiconducteurs et Dilectrques Universit Amar Telidji de Laghouat Laboratoire de Modlisation UniversitAbou BakarBelkaid de Tlemcen Algrie

A novel approach to compute diffusion lengths in solar cells is presented. thus, a simulation is done; it aims to give computational support to the general development of a neural networks （NNs）, which is a very powerful predictive modelling technique used to predict the diffusion length in mono-crystalline silicon solar cells. Furthermore, the computation of the diffusion length and the comparison with measurement data, using the infrared injection method, are presented and discussed.

关键词： diffusion length minority-cartier lifetime infrared injection solar cell prediction modelling

Review of Sodic Soil Reclamation with a Snapshot of Current Research Activity

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Chinese Geographical Science 2022年第6期32卷 1099-1109页

作者： tÓtH tibor Institute for Soil Sciences Centre for Agricultural ResearchBudapest 1022Hungary

For centuries, reclamation of sodic soils has been an essential part of cropping practices in several parts of the world. Parallel to increasing population, the need for new cropland constantly re-evaluates land suitability concepts. therefore, the importance of sodic soils as potential croplands is increasing worldwide. Although theoretically farmers can choose from a wide variety of reclamation options, according to profitability, business plans, and human and financial resources, in practice, few reclamation methods are applied at large scale. this article touches on the early history, 20th Century intensive research, and current trends of sodic soil reclamation. New approaches such as leaching, chemical amendments, addition of organic material, and biological and microbial improvements are discussed, and also brand-new approaches are reviewed. the early history is reviewed using historical books, the achievements of the last hundred years using basic technical literature, mostly books, and the current approaches of our time with fresh publications, mostly papers and two very recent conferences published in English.

关键词： gypsuming liming chemical reclamation new technology sodic soil

the Effect of Intraband transitions on the Optical Spectra of Metallic Carbon Nanotubes

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Chinese Physics Letters 2013年第7期30卷 172-175页

作者： t.Movlarooy Department of Physics University of ShahroodShahroodIran

First-principles calculations of the electronic structure and linear optical properties of metallic carbon nanotubes are carried out using the full-potential linear-augmented plane-wave *** effect of intraband transition and electric-field polarization on the optical spectra of(5,2)chiral,(15,0)zigzag,and(8,8)armchair metallic carbon nanotubes are *** optical spectra are calculated for both electric-field polarizations,parallel and perpendicular to the axis of the *** is revealed that the optical spectra are anisotropic along these two *** the parallel polarization to the tube axis,adding the intraband transition contributions shows that the dielectric function has singularity at zero frequency due to the screening effect in metallic carbon nanotubes.

关键词： polarization metallic band

Control of seismic and operational vibrations of rotating machines using semi-active mounts

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Earthquake Engineering and Engineering Vibration 2004年第1期3卷 85-100页

作者： R.Rana t.t.Soong Ove Arup & partners Department of Civil Structural.and Environmental EngineeringState University of New York

A dual isolation problem for rotating machines consists of isolation of housing structures from the machine vibrations and protection of machines during an earthquake to maintain their functionality. Desirable characteristics of machine mounts for the above two purposes can differ significantly due to difference in nature of the excitation and performance criteria in the two situations. In this paper, relevant response quantities are identified that may be used to quantify performance and simplified models of rotating machines are presented using which these relevant response quantities may be calculated. Using random vibration approach with a stationary excitation, it is shown that significant improvement in seismic performance is achievable by proper mount design. Results of shaking table experiments performed with a realistic setup using a centrifugal pump are presented. It is concluded that a solution to this dual isolation problem lies in a semi-active mount capable switching its properties from ‘operation-optimum’ to ‘seismic-optimum’ at the onset of a seismic event.

关键词： rotating machines simple modeling seismic control operational control semi-active control

Effects of gamma-ray irradiation on electronic and non-electronic equipment of Large Helical Device

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Plasma Science and technology 2017年第2期19卷 95-100页

作者： K OGAWA t NISHItANI M ISOBE M SAtO M YOKOtA H HAYASHI t KOBUCHI t NISHIMURA National Institute for Fusion Science National Institutes of Natural Sciences322-6 0roshi-choToki 509-5292Japan SOKENDAI(the Graduate University for Advanced Studies) School of Physical Sciences322-6 Oroshi-choTold 509-5292Japan

In a deuterium operation on the Large Helical Device, the measurement and control equipment placed in the toms hall must survive under an environment of radiation, to study the effects of gamma-ray irradiation on the equipment, an irradiation experiment is performed at the Cobalt-60 irradiation facility of Nagoya University. transient and permanent effects on a personal computer, media converters, programmable logic controllers, isolation amplifiers, a web camera, optical flow meters, and water sealing gaskets are experimentally surveyed. transient noise appears on the web camera. Offset of the signal increases with an increase of the integrated dose on the programmable logic controller. the DeviceNet module on the programmable logic controller is broken at the integrated dose of 72 Gy, which is the expected range of the integrated dose of the toms hall. the other equipment can survive under the gamma-ray field in the toms hall.

关键词： large helical device gamma-ray irradiation radiation effect

Stochastic framework for modeling the linear apparent behavior of complex materials:Application to random porous materials with interphases

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Acta Mechanica Sinica 2013年第6期29卷 773-782页

作者： J.Guilleminot t.t.Le C.Soize Universit Paris-Est Laboratoire Modlisation et Simulation Multi EchelleMSME UMR8208 CNRS5 Bd Descartes77454 Marne la ValleFrance

this paper is concerned with the modeling of randomness in multiscale analysis of heterogeneous materials. More specifically, a framework dedicated to the stochastic modeling of random properties is first introduced. A probabilistic model for matrix-valued second-order random fields with symmetry propertries, recently proposed in the literature, is further reviewed. Algorithms adapted to the Monte Carlo simulation of the proposed representation are also provided. the derivations and calibration procedure are finally exemplified through the modeling of the apparent properties associated with an elastic porous microstructure containing stochastic interphases.

关键词： Apparent properties MaxEnt Probabilistic model