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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

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Analytical characterization and structure elucidation of metabolites from Aspergillus ochraceus MP2 fungi

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Asian Pacific journal of Tropical Biomedicine 2011年第5期1卷 376-380页

作者： Meenupriya j Thangaraj M Department of Biotechnology Sathyabama University CAS in Marine biology Annamalai university

Objective:To isolate and characterize the bioactive secondary metabolites from Aspergillus ochraceus(***)MP2 ***:The anti bacterial activity of marine sponge derived fungi *** MP2 was thoroughly investigated against antagonistic human *** optimum inhibitory concentration of the fungi in the elite solvent was also *** promising extracts that showed good antimicrobial activity were subjected to further analytical separation to get individual distinct metabolites and the eluants were further identified by GC MS instrumental *** molecular characterization of the elite fungal strains were done by isolating their genomic DNA and amplify the internal transcribed spacer(US)region of 5.8s rRNA using specific ITS *** novelty of the strain was proved by homology search tools and elite sequences was submitted to ***:Three bioactive compounds were characterized to reveal their identity,chemical formula and *** first elutant was identified asα-Campholene aldehyde with chemical fonnula C_(10)H_(16)O and molecular weight 152 *** second elutant was identified as Lucenin-2 and chemical fonnula C_(27)H_(30)O_(16)and molecular weight *** third elutant was identified as 6-Ethyloct-3-yl-2-ethylhexyl ester with Chemical fonnula C_(26)H_(42)O_4 with molecular weight 418 ***:The isolated compounds showed significant antimicrobial activity against potential human *** secondary metabolites represent a large source of compounds endowed with ingenious structures and potent biological activities.

关键词： Marine sponge derived fungi Aspergillus ochraceus Bioactive metabolites Antibacterial activity Analytical characterization Fungi Apergillus Bioactive secondary metabolite Antagonistic human pathogen Antimicrobial activity Bioactive compounds

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Performance assessment of borehole arrangements for the design of rectangular shallow foundation systems

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journal of Rock Mechanics and Geotechnical Engineering 2023年第12期15卷 3291-3304页

作者： Marcin Chwała Danko j.j.rez Hector A.jensen Michael Beer Wrocław University of Science and Technology Poland Institute for Risk and Reliability Leibniz University HannoverGermany Departamento de Obras Civiles Universidad Técnica Federico Santa MaríaChile International joint Research Center for Resilient Infrastructure&International joint Research Center for Engineering Reliability and Stochastic Mechanics Tongji UniversityShanghai200092China Institute for Risk and Uncertainty and School of Engineering University of LiverpoolUnited Kingdom

This study proposes a framework to evaluate the performance of borehole arrangements for the design of rectangular shallow foundation systems under spatially variable soil conditions. Performance measures are introduced to quantify, for a fixed foundation layout and given soil sounding locations, the variability level of the foundation system bearing capacities in terms of their mean values and standard deviations. To estimate these measures, the recently proposed random failure mechanism method (RFMM) has been adopted and extended to consider any arrangement of rectangular foundations and boreholes. Hence, three-dimensional bearing capacity estimation under spatially variable soil can be efficiently performed. Several numerical examples are presented to illustrate the applicability of the proposed framework, including diverse foundation arrangements and different soil correlation structures. Overall, the proposed framework represents a potentially useful tool to support the design of geotechnical site investigation programs, especially in situations where very limited prior knowledge about the soil properties is available.

关键词： Foundations Geotechnical engineering Bearing capacity Optimal borehole placement Soil spatial variability

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Prediction of TBM jamming risk in squeezing grounds using Bayesian and artificial neural networks

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journal of Rock Mechanics and Geotechnical Engineering 2020年第1期12卷 21-31页

作者： Rohola Hasanpour jamal Rostami jürgen Schmitt Yilmaz Ozcelik Babak Sohrabian Institute for Tunneling and Construction Management Ruhr-University BochumBochumGermany Department of Mining Engineering Colorado School of MinesGoldenUSA Department of Civil Engineering Darmstadt University of Applied ScienceDarmstadtGermany Department of Mining Engineering Hacettepe UniversityAnkaraTurkey Faculty of Mining and Metallurgical Engineering Urmia University of TechnologyUrmiaIran

This study presents an application of artificial neural network(ANN)and Bayesian network(BN)for evaluation of jamming risk of the shielded tunnel boring machines(TBMs)in adverse ground conditions such as squeezing *** analysis is based on database of tunneling cases by numerical modeling to evaluate the ground convergence and possibility of machine *** results of initial numerical analysis were verified in comparison with some case studies.A dataset was established by performing additional numerical modeling of various scenarios based on variation of the most critical parameters affecting shield *** includes compressive strength and deformation modulus of rock mass,tunnel radius,shield length,shield thickness,in situ stresses,depth of over-excavation,and skin friction between shield and *** the dataset,an ANN was trained to predict the contact pressures from a series of ground properties and machine ***,the continuous and discretized BNs were used to analyze the risk of shield *** results of these two different BN methods are compared to the field observations and summarized in this *** developed risk models can estimate the required thrust force in both *** BN models can also be used in the cases with incomplete geological and geomechanical properties.

关键词： Bayesian network(BN) Artificial neural network(ANN) Shielded tunnel boring machine(TBM) jamming risk Numerical simulation Squeezing ground

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Does a shift in shade tolerance as suggested by seedling morphology explain differences in regeneration success of northern red oak in native and introduced ranges?

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journal of Forestry Research 2022年第3期33卷 949-962页

作者： Peter Nosko Kerri Moreau Christian Kuehne Kelly C.Major jürgen Bauhus Department of Biology and Chemistry Nipissing UniversityNorth BayONP1B 8L7Canada Chair of Silviculture Freiburg University79085FreiburgGermany Division of Forestry and Forest Resources Norwegian Institute of Bioeconomy ResearchP.O.Box 1151431ÅsNorway Tulloch Engineering 1942 Regent StUnit LSudburyONP3E 5V5Canada

Across North America, forests dominated by Quercus rubra L. (northern red oak), a moderately shade-tolerant tree species, are undergoing successional replacement by shade-tolerant competitors. Under closed canopies, Q. rubra seedlings are unable to compete with these shade-tolerant species and do not recruit to upper forest strata. In Europe, natural regeneration of introduced Q. rubra is often successful despite the absence of fire, which promotes regeneration in the native range. Considering that understorey light availability is a major factor affecting recruitment of seedlings, we hypothesized that Q. rubra seedlings are more shade tolerant in the introduced range than in the native range. Morphological traits and biomass allocation patterns of seedlings indicative of shade tolerance were compared for Q. rubra and three co-occurring native species in two closed-canopy forests in the native range (Ontario, Canada) and introduced range (Baden-Württemburg, Germany). In the native range, Q. rubra allocated a greater proportion of biomass to roots, while in the introduced range, growth and allocation patterns favored the development of leaves. Q. rubra seedlings had greater annual increases in height, diameter and biomass in the introduced range. Q. rubra seedlings in the introduced range were also younger;however, they had a mean area per leaf and a total leaf area per seedling that were five times greater than seedlings in the native range. Such differences in morphological traits and allocation patterns support the hypothesis that Q. rubra expresses greater shade tolerance in the introduced range, and that natural regeneration of Q. rubra is not as limited by shade as in the native range. The ability of Q. rubra seedlings to grow faster under closed canopies in Europe may explain the discrepancy in regeneration success of this species in native and introduced ranges. Future research should confirm findings of this study over a greater geographical range in native

关键词： Alien species Cross-continental study Forest regeneration Introduced species Seedling morphology Plant functional traits Quercus rubra

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An equivalent dipole analysis of PZT ceramics and lead-free piezoelectric single crystals

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journal of Advanced Dielectrics 2016年第2期6卷 56-60页

作者： Andrew j.Bell Institute for Materials Research School of Chemical and Process Engineering University of LeedsLeedsLS29JTUK

The recently proposed Equivalent Dipole Model for describing the electromechanical properties of ionic solids in terms of 3 ions and 2 bonds has been applied to PZT ceramics and lead-free single crystal piezoelectric materials,providing analysis in terms of an effective ionic charge and the asymmetry of the interatomic force *** PZT it is shown that,as a function of composition across the morphotropic phase boundary,the dominant bond compliance peaks at 52%ZrO_(2).The stiffer of the two bonds shows little composition dependence with no anomaly at the phase *** effective charge has a maximum value at 50%ZrO_(2),decreasing across the phase boundary region,but becoming constant in the rhombohedral *** single crystals confirm that both the asymmetry in the force constants and the magnitude of effective charge are equally important in determining the values of the piezoelectric charge coefficient and the electromechanical coupling *** are apparently temperature dependent,increasing markedly on approaching the Curie temperature.

关键词： Piezoelectricity ferroelectricity modeling

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The developmental changes in intestinal epithelial cell proliferation,differentiation,and shedding in weaning piglets

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Animal Nutrition 2022年第2期9卷 214-222页

作者： Min wang Lixia wang Xian Tan Lei wang Xia Xiong Yancan wang Qiye wang Huansheng Yang Yulong Yin Hunan International joint Laboratory of Animal Intestinal Ecology and Health Laboratory of Animal Nutrition and Human HealthCollege of Life SciencesHunan Normal UniversityChangsha 410081HunanChina Hunan Provincial Key Laboratory of Animal Nutritional Physiology and Metabolic Process Hunan Provincial Engineering Research Center for Healthy Livestock and Poultry ProductionKey Laboratory of Agro-ecological Processes in Subtropical RegionInstitute of Subtropical AgricultureChinese Academy of SciencesChangsha 410125HunanChina

Intestinal epithelial homeostasis plays an important role in intestinal morphology and ***,the developmental changes in intestinal epithelial cell turnover in piglets during early weaning are unknown so ***,the aim of this work was to detect changes in piglet gut development from weaning to post-weaning d ***,40 piglets were used in the present study,and 8 piglets were randomly selected for sampling at d 0,1,3,7 and 14 post-weaning,*** results showed that weaning stress significantly affected small intestinal morphological architecture,and this impact was the worst on d 3,and then returned to normal on d ***,the number of the marker of proliferation Ki-67(Ki67)positive cells was decreased on d 1 and 3,and then recovered on d 14(Pj.j.nal epithelial cell shedding on d 1 to 7 compared on d 0(P<0.05).Moreover,weaning remarkably affected the number of small intestinal enterocytes,goblets and endocrine cells(P<0.05),and there were also significant differences in genes expression related to proliferation and differentiation(P<0.05).Additionally,the mechanistic target of rapamycin(mTOR)phosphorylation level was higher on d 3(P<0.05).However,the Wingless/Int1(WNT)/b-catenin pathway was not influenced by post-weaning *** together,weaning induced noteworthy changes in intestinal epithelial cell proliferation,differentiation and shedding,and the mTOR signaling pathway was involved in this *** findings provide a cellular mechanism for intestinal developmental changes during weaning *** may provide nutritionists with better insight into designing efficient in-feed alternatives for preventing the unfavorable gut development in weaning piglets.

关键词： Intestinal epithelial cell Proliferation Differentiation Shedding Weaning piglet

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Experimental determination of grain density function of AZ91/SiC composite with different mass fractions of SiC and undercoolings using heterogeneous nucleation model

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China Foundry 2011年第1期8卷 101-106页

作者： j.Lelito P.Zak j.S.Suchy W.Krajewski A.L.Greer P.Darlak Department of Foundry Engineering Processes AGH University of Science and Technology Department of Materials Science & Metallurgy University of Cambridge Foundry Institute

The grain density,Nv,in the solid state after solidification of AZ91/SiC composite is a function of maximum undercooling,ΔT,of a liquid *** type of function depends on the characteristics of heterogeneous nucleation sites and number of SiC present in the *** aim of this paper was selection of parameters for the model describing the relationship between the grain density of primary phase and *** model in connection with model of crystallisation,which is based on chemical elements diffusion and grain interface kinetics,can be used to predict casting quality and its *** models have parameters,which exact values are usually not known and sometimes even their physical meaning is under *** parameters can be obtained after mathematical analysis of the experimental *** composites with 0,1,2,3 and 4wt.% of SiC particles were *** AZ91 alloy was a matrix of the composite reinforcement SiC *** composite was cast to prepare four different thickness *** were taken from the region near to the thermocouple,to analyze the undercooling for different composites and thickness plates and its influence on the grain *** microstructure and thermal analysis gave set of values that connect mass fraction of SiC particles,and undercooling with grain *** values were used to approximate nucleation model adjustment *** model can be very useful in modelling composites microstructure.

关键词： heterogeneous nucleation mass fraction of SiC particles AZ91/SiC composite grain density mathematical modelling

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A novel approach to determine residual stress field during FSW of AZ91 Mg alloy using combined smoothed particle hydrodynamics/neuro-fuzzy computations and ultrasonic testing

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journal of Magnesium and Alloys 2021年第4期9卷 1311-1335页

作者： A.R.Eivani H.Vafaeenezhad H.R.jafarian j.Zhou School of metallurgy and materials engineering iran university of science and technology^nartnaktehraniran department of biomechanical engineering delft university of technologymekehveg 22628 cd delftthe netherlands

The faults in welding design and process every so often yield defective parts during friction stir welding(FSW).The development of numerical approaches including the finite element method(FEM)provides a way to draw a process paradigm before any physical *** is not practical to simulate all possible designs to identify the optimal FSW practice due to the inefficiency associated with concurrent modeling of material flow and heat dissipation throughout the *** study intends to develop a computational workflow based on the mesh-free FEM framework named smoothed particle hydrodynamics(SPH)which was integrated with adaptive neuro-fiizzy inference system(ANFIS)to evaluate the residual stress in the FSW *** integrated SPH and ANFIS methodology was established and the well-trained ANIS was then used to predict how the FSW process depends on its *** verify the SPH calculation,an itemized FSW case was performed on AZ91 Mg alloy and the induced residual stress was measured by ultrasonic *** suggested methodology can efficiently predict the residual stress distribution throughout friction stir welding of AZ91 alloy.

关键词： Friction stir welding(FSW) Smoothed particle hydrodynamics(SPH) Adaptive neuro-fuzzy inference system(ANFIS) Ultrasonic Residual stress

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Ultra-sensitive bioanalysis of the therapeutic peptide exenatide for accurate pharmacokinetic analyses at effective plasma concentrations utilizing UPLC-MS/MS

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journal of Pharmaceutical Analysis 2020年第3期10卷 233-239页

作者： Max Sauter Philipp Uhl jürgen Burhenne Walter E.Haefeli Department of Clinical Pharmacology and Pharmacoepidemiology Heidelberg University HospitalIm Neuenheimer Feld 41069120HeidelbergGermany

Exenatide is the first approved glucagon-like peptide 1 receptor agonist subcutaneously or intramuscularly injected for the treatment of type 2 diabetes *** therapeutic plasma concentrations are in the low pg/mL range,therefore requiring ultra-sensitive *** enable the accurate evaluation of pharmacokinetic studies,we established a UPLC-MS/MS assay with a lower limit of quantification(LLOQ)of 5 pg/mL(1.2 pM)using 200μL of plasma,validated acco rding to FDA's and EMA's pertinent *** was isolated from plasma with solid phase extraction utilizing anionexchange *** was performed with positive electrospray ionization tandem mass spectrometry in the selected reaction monitoring *** calibrated concentration range of 5-10,000 pg/mL was linear showing co rrelation coefficients>*** and intraday accuracy ranged from 97.5%to 105.4%with corre sponding precision of<10.9%.Accuracy at the LLOQ ranged from 93.0%to 102.5%with corresponding precision of<15.9%.Because of the validity of a 10-fold dilution QC(accuracy 111.2%),the assay is suitable for exenatide quantification up to 100,000 pg/*** ultra-sensitive assay's applicability was demonstrated by the quantification of exenatide plasma concentrations and pharmacokinetics after intravenous and nasal administration to beagle dogs.

关键词： Exenatide Nasal Intravenous UPLC Tandem mass spectrometry Pharmacokinetics

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