检索结果-南通市图书馆

Combustion characteristics of low-quality lignite for different bed material sphericities in a circulati.g.fluidized bed boiler:A numerical study

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第7期90卷 364-382页

作者： Barış gürel gülşah Karaca Dolgun Osman ipek Ali Keçebaş Department of Mechanical Engineering Engineering FacultySüleyman Demirel UniversityÇünürIspartaTurkey Department of Energy Systems Engineering Technology FacultyMuğla SıtkıKoçman UniversityKötekliMenteşeMuğlaTurkey

This study delves into the combustion behavior of various lignite types within a circulati.g.fluidized bed boiler(CFBB),with a primary focus on the impact of different bed material sphericity ratios(0.5,0.7,and 0.9).Utilizi.g.bed material with a sphericity ratio of 0.9 sourced from theÇan power plant and verified through experimentation,the research reveals several key ***,furnace temperatures tended to rise with higher sphericity ratios,albeit with variations between lignite types,particularly highlighti.g.the complexity of this relationship in the case of gLi-Tunçbilek *** levels in the combustion chamber remained consistent across different sphericity ratios,indicati.g.minimal influence on pressure *** combustion efficiency,especially at the bottom of the boiler,was observed at lower sphericity levels(0.5 and 0.7)forÇan lignite,as reflected in CO_(2) mole *** NO_(x) emissions generally decreased with lower sphericity,the sensitivity to sphericity varied by lignite type,with i.g.n lignite showcasi.g.low NO_(x) but high SO_(2) emissions,underscori.g.the intricate interplay between lignite properties,sphericity,and ***,this study advances our understandi.g.of CFBB combustion dynamics,offeri.g.insights valuable for optimizi.g.performance and emissions control,particularly in lignite-based power.

关键词： Circulati.g.fluidized bed boiler Computational particle fluid dynamics method Particle sphericity ratios NO_(x)and SO_(2)emissions Energy production efficiency

investigation of the transformation of organic matter of carbonate deposits of the Semiluksky-Mendymsky horizon under hydrothermal conditions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Petroleum 2024年第2期10卷 216-223页

作者： S.M.Petrov A.i.Lakhova E.g.Moiseeva A.g.Safiulina institute of Petroleum Chemistry and Nanotechnologies Kazan National Research Technological University institute of geology and Oil and gas Technologies Kazan Federal University

The paper presents the results of studies on the transformation of the organic matter of siliceous-clayey carbonate rocks of the Semiluksko-Mendymsky horizon of the Romashkino oil field in a hydrothermal fluid for an hour（with a water-to-rock ratio of 33） at 340℃ and 380℃ and pressu res of 17 and 20 *** a result of hydrothermal treatment,at 340℃ and 17 MPa,based on nitrogen porosimetry and electron microscopy data,transformations of rock-formi.g.minerals in the rock are *** lead to an increase in the volume and average diameter of mesopores in it and the formation of micropores,as well,which improve its filtration *** the same time,the amount of kerogen in the composition of the organic matter decreases and the yield of the petroleum hydrocarbon extract increases,in which,accordi.g.to the SARA analysis,the content of asphaltenes increases and the content of resins,aromatic and saturated hydrocarbons *** the composition of aroatic hydrocarbons,the proportion of a lkyltri methyl benzenes and dibenzothiophenes increases,phenanthrene homologues appear,and in the composition of saturated hydrocarbons,the amount of iso-structure alkanes decreases relative to the content of linear *** the temperature and pressure of the hydrothermal fluid to 380℃ and 20 MPa increases the degree of kerogen conversion from 12.4% to 23.6%.At the same time,changes occurri.g.in the component composition of petroleum hydrocarbon extracts remains similar to the experiments carried out at 340℃ and 17 MPa;the content of naphthalenes decreases,the content of dibenzothiophenes increases and C11-C17,C19-C22alkyltrimethylbenzenes *** to iR spectroscopy,with increasi.g.temperature and pressure of the hydrothermal fluid the intensity of the absorption bands of the aromatic ri.g.aliphatic fragments,and oxygen-containi.g.groups increases in resins;the structural-group composition of asphaltenes changes little:aromaticity and the content of condensed

关键词： Carbonate deposits Organic matter Hydrothermal fluid Mobile hydrocarbons

Phase composition,conductivity,and sensor properties of cerium-doped indium oxide

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Nano Materials Science 2024年第2期6卷 193-200页

作者： M.i.ikim g.N.gerasimov V.F.gromov O.J.ilegbusi L.i.Trakhtenberg N.N.Semenov Federal Research Center for Chemical Physics of RAS MoscowRussia University of Central Florida OrlandoFLUSA Moscow institute of Physics and Technology(State University) DolgoprudnyMoscow RegionRussia Lomonosov Moscow State University MoscowRussia

The hydrothermal synthesis of in_(2)O_(3)and CeO_(2)–in_(2)O_(3)is investigated as well as the properties of sensor layers based on these *** the synthesis of in_(2)O_(3),intermediate products in(OH)_(3)and inOOH are formed,which are the precursors of stable cubic(c-in_(2)O_(3))and metastable rhombohedral(rh-in_(2)O_(3))phases,respectively.A transition from c-in_(2)O_(3)to rh-in_(2)O_(3)is observed with the addition of CeO_(2).The introduction of cerium into rh-in_(2)O_(3)results in a decrease in the sensor response to hydrogen,while it increases in composites based on c-in_(2)O_(3).The data on the sensor activity of the composites correlate with XPS results in which CeO_(2)causes a decrease in the concentrations of chemisorbed oxygen and oxygen vacancies in rh-in_(2)O_(3).The reverse situation is observed in composites based on c-in_(2)O_(3).Compared to in_(2)O_(3)and CeO_(2)–in_(2)O_(3)obtained by other methods,the synthesized composites demonstrate maximum response to H_(2)at low temperatures by 70–100℃,and have short response time(0.2–0.5 s),short recovery time(6–7 s),and long-term stability.A model is proposed for the dependence of sensitivity on the direction of electron transfer between in_(2)O_(3)and CeO_(2).

关键词： Cerium oxide indium oxide Nanocomposite Hydrothermal method Cubic phase Rhombohedral phase Sensor response Conductivity Hydrogen Response/recovery time

维普期刊数据库

Height-diameter models for Ki.g.Boris fir(Abies borisii regis Mattf.) and Scots pine(Pinus sylvestris L.) in Olympus and Pieria Mountains, greece

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2024年第5期21卷 1475-1490页

作者： Dimitrios i.RAPTiS Dimitra PAPADOPOULOU Angeliki PSARRA Athanasios A.FALLiAS Aristides g.TSiTSANiS Vassiliki KAZANA Renewable Natural Resource Management and Bioeconomy Laboratory Department of Forest and Natural Environment SciencesInternational Hellenic University66100 DramaGreece

in forest science and practice, the total tree height is one of the basic morphometric attributes at the tree level and it has been closely linked with important stand attributes. in the current research, sixteen nonlinear functions for height prediction were tested in terms of their fitti.g.ability against samples of Abies borisii regis and Pinus sylvestris trees from mountainous forests in central greece. The fitti.g.procedure was based on generalized nonlinear weighted regression. At the final stage, a five-quantile nonlinear height-diameter model was developed for both species through a quantile regression approach, to estimate the entire conditional distribution of tree height, enabli.g.the evaluation of the diameter impact at various quantiles and providi.g.a comprehensive understandi.g.of the proposed relationship across the distribution. The results clearly showed that employi.g.the diameter as the sole independent variable, the 3-parameter Hossfeld function and the 2-parameter N?slund function managed to explain approximately 84.0% and 81.7% of the total height variance in the case of Ki.g.Boris fir and Scots pine species, respectively. Furthermore, the models exhibited low levels of error in both cases(2.310m for the fir and 3.004m for the pine), yieldi.g.unbiased predictions for both fir(-0.002m) and pine(-0.004m). Notably, all the required assumptions for homogeneity and normality of the associated residuals were achieved through the weighti.g.procedure, while the quantile regression approach provided additional insights into the height-diameter allometry of the specific species. The proposed models can turn into valuable tools for operational forest management planni.g. particularly for wood production and conservation of mountainous forest ecosystems.

关键词： generalized nonlinear weighted regression Monte Carlo cross-validation Mountainous ecosystems Quantile regression Central greece

维普期刊数据库

Microstructure， electrochemical， wear and corrosive wear performance of laser-based powder bed fusion(lpbf) and wrought biomedical Ti-6Al-4V alloys

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2024年

作者： A.g.Lekatou B.V.Efremenko V.Haoui V.g.Efremenko S.Emmanouilidou V.i.Zurnadzhy i.Petryshynets Yu.g.Chabak i.i.Sili Laboratory of Applied Metallurgy， Department of Materials Science and Engineeri.g. School of Engineeri.g. University of ioannina institute of Materials Science and Computi.g. University Research Center of ioannina (URCi) Pryazovskyi State Technical University， Department of Physics institute of Materials Research of Slovak Academy of Sciences

Wrought and laser powder bed fusion （LPBF） Ti-6Al-4V specimens were comparatively evaluated， with the objective to determine LPBF Ti-6-4’s suitability for biomedical applications. Testi.g.included nanoindentation， cyclic polarization in simulated body fluid （SBF， 37 ℃ ）， and dry and SBF “Ball-on-Plate” slidi.g. Wrought Ti-6-4 exhibited a lamellar （α+β） microstructure， whereas LPBF displayed a fine-grained α'-martensite microstructure. LPBF Ti-6-4 demonstrated ～3% higher indentation modulus and ～32% higher hardness， while wrought Ti-6-4 showed ～8% higher plasticity. Both alloys exhibited low corrosion rates (10–5mA/cm2order) and true passivity (10–4mA/cm2order). No localized corrosion was observed in either alloy， except for occasional metastable pitti.g.in the LPBF alloy. However， LPBF Ti-6-4 presented higher corrosion rate and passive current， ascribed to its martensitic structure. Duri.g.dry slidi.g. LPBF Ti-6-4 exhibited ～14% lower volume loss compared to wrought Ti-6-4. Slidi.g.in SBF increased volume losses for both alloys， with wear resistances nearly equalized， as the advantage of LPBF Ti-6-4 decreased due to more intensive wear-accelerated corrosion induced by the stressed martensite. Overall， the results demonstrate the suitability of LPBF Ti-6Al-4V for biomedical uses.

关键词：

Exact solutions for magnetohydrodynamic nanofluids flow and heat transfer over a permeable axisymmetric radially stretchi.g.shrinki.g.sheet

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第2期33卷 108-114页

作者： U.S.Mahabaleshwar g.P.Vanitha L.M.Pérez Emad H.Aly i.Pop Department of Studies in Mathematics Davangere UniversityShivagangothriDavangereIndia Departamento de F´ısica FACIUniversidad de Tarapac´aCasilla 7DAricaChile Department of Mathematics Faculty of EducationAin Shams UniversityRoxyCairoEgypt Department of Mathematics Babes-Bolyai University400084 Cluj-NapocaRomania

We report on the magnetohydrodynamic impact on the axisymmetric flow of Al_(2)O_(3)/Cu nanoparticles suspended in H_(2)O past a stretched/shrinked *** the use of partial differential equations and the correspondi.g.thermophysical characteristics of nanoparticles,the physical flow process is *** resultant nonlinear system of partial differential equations is converted into a system of ordinary differential equations usi.g.the suitable similarity *** transformed differential equations are solved *** of the magnetic parameter,solid volume fraction and stretchi.g.shrinki.g.parameter on momentum and temperature distribution have been analyzed and interpreted *** skin friction and Nusselt number were also *** addition,existence of dual solution was deduced for the shrinki.g.sheet and unique solution for the stretchi.g.***,Al_(2)O_(3)/H_(2)O nanofluid flow has better thermal conductivity on compari.g.with Cu/H_(2)O ***,it was found that the first solutions of the stream are stable and physically realizable,whereas those of the second ones are unstable.

关键词： magnetohydrodynamic nanofluid stretchi.g.shrinki.g.sheet axisymmetric flow analytical solution suction/injection

维普期刊数据库

Applications of Soft Computi.g.Methods in Backbreak Assessment in Surface Mines: A Comprehensive Review

在线全文

学校读者我要写书评

暂无评论

Computer Modeli.g.in Engineeri.g.& Sciences 2024年第9期140卷 2207-2238页

作者： Mojtaba Yari Manoj Khandelwal Payam Abbasi Evangelos i.Koutras Danial Jahed Armaghani Panagiotis g.Asteris Department of Mini.g.Engineering Faculty of EngineeringMalayer UniversityMalayer***Iran institute of innovation Science and SustainabilityFederation University AustraliaBallaratVIC 3350Australia Marane Olia Ornamental Stone Mine Sanandaj***Iran Computational Mechanics Laboratory School of Pedagogical and Technological EducationAthens15122Greece School of Civil and Environmental Engineering University of Technology SydneySydneyNSW 2007Australia

geo-engineeri.g.problems are known for their complexity and high uncertainty levels,requiri.g.precise defini-tions,past experiences,logical reasoni.g.mathematical analysis,and practical insight to address them *** Computi.g.SC)methods have gained popularity in engineeri.g.disciplines such as mini.g.and civil engineeri.g.due to computer hardware and machine learni.g.*** traditional hard computi.g.approaches,SC models use soft values and fuzzy sets to navigate uncertain *** study focuses on the application of SC methods to predict backbreak,a common issue in blasti.g.operations within mini.g.and civil ***,which refers to the unintended fracturi.g.of rock beyond the desired blast perimeter,can significantly impact project timelines and *** study aims to explore how SC methods can be effectively employed to anticipate and mitigate the undesirable consequences of blasti.g.operations,specifically focusi.g.on backbreak *** research explores the complexities of backbreak prediction and highlights the potential benefits of utilizi.g.SC methods to address this challengi.g.issue in geo-engineeri.g.projects.

关键词： Backbreak blasting soft computi.g.methods prediction theory-guided machine learning

BaTiO3 solid solutions co-doped with gd3+ and Eu3+:Synthesis,structural evolution and dielectric properties

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Rare Earths 2024年第10期42卷 1920-1926页

作者： R.Martínez-López M.Pérez-Labra J.A.Romero-Serrano F.R.Barrientos-Hernández M.Reyes-Pérez M.i.Valenzuela-Carrillo g.Urbano-Reyes V.E.Reyes-Cruz g.i.Dávila-Pulido Academic Area of Earth Sciences and Materials Autonomous University of Hidalgo State Metallurgy and Materials Department ESIQIE-IPNUPALM Autonomous University of Coahuila Boulevard Adolfo López Mateos S/n

in this paper,the synthesis,structural evolution,and dielectric properties of BaTiO3solid solutions codoped with rare earth elements(gd3+and Eu3+) prepared usi.g.the solid-state reaction method are *** pure precursor powders of BaCl3,TiO2,gd2O3,and Eu2O3were mixed in stoichiometric proportions,ground in an agate mortar before bei.g.uniaxially pressed at 250 MPa and sintered at 1300℃ in air atmosphere for 6 h to obtain Ba1-3xgd2xTi1-3xEu4xO3（x=0,0.0015,0.01 and0.1）.X-ray diffraction（XRD） and Rietveld's refinement results reveal the crystal phase ferroelectric tetragonal BaTiO3for the samples with x=0,0.0015 and 0.01, as well as a consistent increment in the lattice parameters caused by the *** solubility limit of gd3+and Eu3+in the BaTiO3structure is reached for the sample with x>0.01,and the orthorhombic Eu2TiO5and monoclinic BaTi2O5secondary phases were *** Raman results show the characteristic peaks of ferroelectric tetragonal BaTiO3around 716 cm-1（LO of A1 symmetry）,515 cm-1（TO of A1 symmetry）,and 305 cm-1（B1）.The maximum relative permittivity measured at 1 kHz was recorded to be 6151.8 for the sample with x=0.0015,and a decrease in the Curie temperature to 105℃ with respect to the undoped sample was *** punctual microanalysis for the samples with x=0.0015,0.01,and 0.1 reveals grains composed of Ba,Ti,O,gd,and Eu homogeneously distributed in the *** Ba/Ti ratios for samples with x=0.0015,0.01 and 0.1 are 2.86,2.91,and 0.68,respectively,indicati.g.substitution at the Ti site for samples with x=0.0015 and 0.01 and a substitution at the Ba site for the sample with x=0.1.

关键词： BaTiO3 Doping Europium gadolinium Rare earths Synthesis

Usi.g.fracture-based continuum modeli.g.of coupled geomechanical-hydrological processes for numerical simulation of hydraulic fracturing

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and geotechnical Engineering 2024年第5期16卷 1582-1599页

作者： goodluck i.Ofoegbu gNO Modeli.g.Research LLC. San AntonioTX78253USA

This paper describes numerical simulation of hydraulic fracturi.g.usi.g.fracture-based continuum modeli.g.FBCM)of coupled geomechanical-hydrological processes to evaluate a technique for high-density fracturi.g.and fracture *** simulations are innovative because of modeli.g.discrete fractures explicitly in continuum analysis.A key advantage of FBCM is that fracture initiation and propagation are modeled explicitly without changi.g.the domain grid(*** re-meshi.g..Further,multiple realizations of a preexisti.g.fracture distribution can be analyzed usi.g.the same domain *** simulated hydraulic fracturi.g.technique consists of pressurizi.g.multiple wells simultaneously:initially without permeati.g.fluids into the rock,to seed fractures uniformly and at high density in the wall rock of the wells;followed by fluid injection to propagate the seeded fracture density *** combines the ease of continuum modeli.g.with the potential accuracy of modeli.g.discrete fractures and fracturi.g.*** are modeled as piecewise planar based on intersections with domain elements;fracture geometry stored as continuum properties is used to calculate parameters needed to model individual fractures;and rock behavior is modeled through tensorial aggregation of the behavior of discrete fractures and unfractured *** are presented for previously unfractured rock and for rock with preexisti.g.fractures of horizontal,shallow-dippi.g.steeply dippi.g.or vertical *** of a si.g.e-well model are used to determine the pattern and spaci.g.for a multiple-well *** results illustrate high-density fracturi.g.and fracture cagi.g.through simultaneous fluid injection in multiple wells:for previously unfractured rock or rock with preexisti.g.shallow-dippi.g.or horizontal fractures,and in situ vertical compressive stress greater than *** preexisti.g.fractures are steeply dippi.g.or vertical,and consideri.g.the same in situ

关键词： Discrete fracture Fracture-based continuum modeling Fracture caging High-density fracturing Hydraulic fracturing Preexisti.g.fracture