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A numerical investigation of CO2 dilution on the thermochemical characteristics of a swirl stabilized diffusion flame

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Applied Mathematics and Mechanics(English Edition) 2020年第2期41卷 327-348页

作者： S.VAKILIPOUR Y.TOHIDI J.AL-ZAILI R.RIAZI Faculty of New Sciences and Technologies University of TehranNorth Kargar StreetTehranIran Department of Mechanical Engineering University of ManitobaWinnipegMB R3T 5V6Canada Department of Mechanical Engineering&Aeronautics CityUniversity of LondonNorthampton SquareLondon EC1V 0HBU.K.

The turbulent combustion flow modeling is performed to study the effects of CO_2 addition to the fuel and oxidizer streams on the thermochemical characteristics of a swirl stabilized diffusion flame. A flamelet approach along with three well-known turbulence models is utilized to model the turbulent combustion flow field. The k-ω shear stress transport(SST) model shows the best agreement with the experimental measurements compared with other models. Therefore, the k-ω SST model is used to study the effects of CO_2 dilution on the flame structure and strength, temperature distribution, and CO concentration. To determine the chemical effects of CO_2 dilution, a fictitious species is replaced with the regular CO_2 in both the fuel stream and the oxidizer stream. The results indicate that the flame temperature decreases when CO_2 is added to either the fuel or the oxidizer stream. The flame length reduction is observed at all levels of CO_2 dilution. The H radical concentration indicating the flame strength decreases, following by the thermochemical effects of CO_2 dilution processes. In comparison with the fictitious species dilution, the chemical effects of CO_2 addition enhance the CO mass fraction. The numerical simulations show that when the dilution level is higher, the rate of the flame length reduction is more significant at low swirl numbers.

关键词： swirl stabilized flame CO2 dilution methane-air chemical effect turbulent flame structure steady flamelet model

Optimizing the ratio of the spike to sample for isotope dilution analysis:a case study with selenium isotopes

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Acta Geochimica 2020年第2期39卷 192-202页

作者： Decan Tan Wenpo Xu Zuochen Zhu Shehong Li Guangliang Wu Haibo Qin State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China University of Chinese Academy of Sciences Beijing 100049China Beijing 21st Century International School Beijing 100014China State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesBeijing 100083China

Isotope dilution(ID)method has been widely applied to studies of elemental speciation and certification of the concentrations of geological reference *** of the key factors restricting the application of the ID method is the difficulty in identifying the optimal ratios of the isotope tracer(spike)to sample(S/N)and in estimating the error ***,using Se isotope as an example and employing a Monte Carlo method,we found that the optimal choice of spike and S/N are^(77)Se(spike)and 0.7,*** S/N in the range from 0.1 to 4 can produce sufficiently low errors(<0.4%).Extending this method to other elements such as Cr,Fe,Ni,Sr,Cd and etc.,their optimal spike and S/N were also *** to the optimized parameters of Se,we determined the Se concentrations of geological reference materials(GRMs)by thiol cotton fiber(TCF)-hydride generation *** relative standard deviation is<5%,and the detection limit is reduced to0.1 ng/*** of the measured concentrations are consistent with those recommended by IGGE or reported *** some GRMs,discrepancies(e.g.6.90%for GSS-5)exist between our measurements and previous ones,which can be explained by the inhomogeneity of GRMs and/or the different digestion,purification and measurement methods among laboratories.

关键词： Isotope dilution method Error propagation Mento Carlo Se concentration Geological reference materials

PREDICTION OF THE TEMPERATURE DEPENDENCE OF LIQUID DIFFUSION COEFFICIENTS AT INFINITE dilution BY A GROUP CONTRIBUTION METHOD

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Chinese Journal of Chemical Engineering 1997年第4期5卷 85-88页

作者：何潮洪俞永盛 Department of Chemical Engineering Zhejiang University

1 INTRODUCTIONSince experimental determination of the mutual liquid diffusion coefficients atinfinite dilution is rather complicated,it is important,therefore,to be able to esti-mate the coefficients under various temperatures from one available coefficient ata certain temperature such as *** equations for this purpose are avail-able in many *** examples are the Wilke-Chang equation and the Tynequation,given

关键词： diffusion coefficients infinite dilution group contribution method

Application of Response Surface Methodolody to Prediction of dilution in Plasma Transferred Arc Hardfacing of Stainless Steel on Carbon Steel

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Journal of Iron and Steel Research International 2009年第1期16卷 44-53页

作者： V Balasubramanian A K Lakshminarayanan R Varahamoorthy S Babu Centre for Materials Joining and Research (CEMAJOR) Department of Manufacturing EngineeringAnnamalai UniversityAnnamalai Nagar 608002Tamil NaduIndia

The application of response surface methodology was highlighted to predict and optimize the percentage of dilution of iron-based hardfaced surface produced by the PTA （plasma tratisferred arc welding） process. The experiments were conducted based on five-factor five-level central composite rotatable design with full replication technique and a mathematical model was developed using response surface methodology. Furthermore, the response surface methodology was also used to optimize the process parameters that yielded the lowest percentage of dilution.

关键词： plasma transferred arc hardfacing dilution response surface methodology

Lysozyme refolding at high concentration by dilution and size—exclusion chromatography

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Journal of Zhejiang University Science 2003年第2期4卷 136-141页

作者：高永贵关怡新姚善泾 CHOMan-gi CollegeofLifeScience ZhejiangUniversityHangzhou310027China DepartmentofChemicalandBiochemicalEngineering EngineeringResearchCenter Dong-SeoUniversity69-1Jurea-dongSasangguBusan617-716Korea

This study of renaturation by dilution and size exclusion chromatogra phy (SEC) addition of urea to improve yield as well as the initial and final pro tein concentrations showed that although urea decreased the rate of lysozyme ref o lding, it could suppress protein aggregation to sustain the pathway of correct r efolding at high protein concentration; and that there existed an optimum urea c oncentration in renaturation buffer. Under the above conditions, lysozyme was su ccessfully refolded from initial concentration of up to 40 mg/mL by dilution and 100 mg/mL by SEC, with the yield of the former being more than 40% and that of the latter being 34.8%. Especially, under the condition of 30 min interval time, i.e. τ>2(t_R2 -t_R1 ), the efficiency was increased by 25% and the renaturation buffe r could be recycled for SEC refolding in continuous operation of downstream proc ess.

关键词： Lysozyme refolding Downstream process dilution Size exclusion chromatography Urea

Performance improvement of n-i-p μc-Si:H solar cells by gradient hydrogen dilution technique

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Science China(Technological Sciences) 2009年第6期52卷 1756-1761页

作者： YUAN YuJie HOU GuoFu ZHANG JianJun XUE JunMing CAO LiRan ZHAO Ying GENG XinHua Key Laboratory of Optoelectronic Information Science and Technology of Ministry of Education Key Laboratory of Photo-Electronics Thin Film Devices and Technique of TianjinInstitute of Photo-Electronics Thin Film Devices and TechniqueNankai UniversityTianjin 300071China

High pressure radio frequency plasma enhanced chemical vapor deposition(RF-PECVD)process was adopted to investigate the effect of constant hydrogen dilution technique and gradient hydrogen dilu-tion technique on the structural evolution of intrinsic films and the performance of n-i-p microcrystal-line silicon solar *** experiment results demonstrated that the grain size and crystalline volume fraction along the growth direction of intrinsic films can be controlled and the performance of solar cells can be greatly improved by gradient hydrogen dilution *** initial active-area efficiency of 5.7%(Voc=0.47V,Jsc=20.2mA/cm2,FF=60%)for the μc-Si:H single-junction n-i-p solar cells and an initial active-area efficiency of 10.12%(Voc=1.2V,Jsc=12.05mA/cm2,FF=70%)for the a-Si:H/μc-Si:H tandem n-i-p solar cells has been achieved.

关键词： gradient hydrogen dilution technique microcrystalline silicon n-i-p solar cells

N_(2)and Ar dilution on the premixed biogas jet flame under external acoustic enforcement

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Propulsion and Power Research 2023年第4期12卷 486-504页

作者： Bugrahan Alabas Ilker Yılmaz YakupÇam Department of Aeronautical Engineering Faculty of Aeronautics and AstronauticsErciyes UniversityKayseri 38039Turkey Department of Energy Systems Engineering Faculty of TechnologyGazi UniversityAnkara 06560Turkey Department of Aircraft Maintenance and Repair Faculty of Aeronautics and AstronauticsErciyes UniversityKayseri 38039Turkey

In this study,combustion instabilities and flue gas emission changes under different dilutions of N_(2)(nitrogen)and Ar(argon)of a promising biogas mixture(70%CH4-30%CO_(2))in the fight against greenhouse gas emissions were *** the experiments,additions were made from 0%to 50%at intervals of 10%for both *** order to detect the instability of the flame,external acoustic enforcements at different frequencies was applied through the speakers placed in the combustion chamber *** dynamic pressure fluctuation values were *** results showed that low dilution ratios were effective in reducing flame instability for both inert ***,as the dilution ratio increased,the fuel/air mixture became leaner and blowoff *** the case of comparing two different gases,it has been observed that the effect of argon gas on reducing dynamic pressure fluctuation is *** outlet temperature and brightness values of the flame decreased in both Ar and N_(2)*** and NOx emissions increased with increasing diluent volume for all dilution *** the emissions of the two diluent gases are compared,the CO emission,which was 3134 ppm in the undiluted condition,increased up to 4949 ppm in 50%Ar dilution,while it increased to 4521 ppm in 50%N_(2)dilution.

关键词： Biogas Combustion instabilities Pollutant emissions Gas turbine combustor dilution

dilution OF HORIZONTAL RADIAL JET IN A CURRENT

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Journal of Hydrodynamics 1992年第3期4卷 34-42页

作者： Guo Zhen-ren Xu Zhen-cheng Lin Kui Jiang Wei-qiang South China Institute for Environmental Sciences,Guangzhou 510655,P.R.China

A type of port with a movable cover is designed to increase initial dilution and prevent sea water and sediments from intruding into outfall *** radial jets pro- duced by this type of port in a current are investigated experimentally and *** analysis based on Reynolds'equations and self-similarity hypothesis shows that the maximum ve- locity of radial jets decays with r^(-1.5).The relationships between the width,thickness,average di- lution of a submerged wastefield along flow,and the parameters of the port,jet and ambient are established quantitatively and verified by *** is demonstrated that the dilution of horizontal radial jets is much higher than that of vertical round jets and the surface boil point of the former is much more distant than that of the latter.

关键词： dilution jet wastewater treatment turbulent mixing

NEW ACCURATE METHOD FOR MEASURING VENTRICULAR VOLUME WITH INDICATOR dilution

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Chinese Science Bulletin 1990年第4期35卷 348-350页

作者：徐明瑜 Department of Mathematics Shandong University Jinan 250100 PRC

On the basis of the mass conservation law and in consideration of the rheological and pulsatile properties of blood in the aorta, we greyed the ideal displacement model and gave out a new accurate method for measuring the ventricular volume with indicator dilution. Based on the ideal displacement model a certain amount of indicator q was

关键词： rheological conservation aorta indicator dilution mentioned slightly formulae virtue downstream