检索结果-南通市图书馆

Tree growth is more limited by drought in rear-edge forests most of the times

Forest Ecosystems 2021年第2期8卷 330-344页

作者： J.Julio Camarero Antonio Gazol Gabriel Sangüesa-Barreda marta Vergarechea Raquel Alfaro-Sánchez Nicolás Cattaneo sergio m.vicente-serrano Instituto Pirenaico de Ecología(IPE-CSIC) Avda.Montañana 1005E-50192 ZaragozaSpain Ei FAB-iu FOR University of ValladolidCampus Duques de SoriaE-42004 SoriaSpain NIBIO Norwegian Institute of Bioeconomy ResearchPostboks 155NO-1431ÅsNorway Department of Biology Wilfrid Laurier UniversityN2L 3C575 Univ.Avenue WWaterlooOntarioCanada

Background:Equatorward,rear-edge tree populations are natural monitors to estimate species vulnerability to climate *** to biogeographical theory,exposition to drought events increases with increasing aridity towards the equator and the growth of southern tree populations will be more vulnerable to drought than in central ***,the ecological and biogeographical margins can mismatch due to the impact of ecological factors(topography,soils)or tree-species acclimation that can blur large-scale geographical imprints in trees responses to drought making northern populations more drought ***:We tested these ideas in six tree species,three angiosperms(Fagus sylvatica,Quercus robur,Quercus petraea)and three gymnosperms(Abies alba,Pinus sylvestris and Pinus uncinata)by comparing rear-edge tree populations subjected to different degrees of *** used dendrochronology to compare the radial-growth patterns of these species in northern,intermediate,and southern tree populations at the continental rear *** and conclusions:We found marked variations in growth variability between species with coherent patterns of stronger drought signals in the tree-ring series of the southern populations of ***,***,and *** was also observed in species from cool-wet sites(*** and ***),despite their limited responsiveness to ***,in the case of *** the intermediate population showed the strongest relationship to *** drought-sensitive species as *** and ***,southern populations presented more variable growth which was enhanced by cool-wet conditions from late spring to *** found a trend of enhanced vulnerability to drought in these two *** response of tree growth to drought has a marked biogeographical component characterized by increased drought sensitivity in southern populations even within the species distribution rear ***,the relationship

关键词： Climate change Dendroecology Latitudinal gradient mediterranean forests Standardized evapotranspiration precipitation index(SPEI)

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Decoupled Photovoltaic Power Ramp-rate Calculation method for Perturb and Observe Algorithms

引用

Journal of modern Power Systems and Clean Energy 2022年第4期10卷 932-940页

作者： Jose miguel Riquelme-Dominguez Francisco m.Gonzalez-Longatt sergio martinez Electrical Engineering Department Escuela Tecnica Superior de Ingenieros IndustrialesUniversidad Politecnica de Madrid28006 MadridSpain Department of Electrical Engineering Information Technology and CyberneticsUniversity of South-Eastern Norway3918 PorsgrunnNorway

As photovoltaic energy increasingly penetrates in power systems,transmission system operators have started to request its participation in providing ancillary *** of the demanded services is the power ramp-rate control(PRRC),which attempts to limit the power ramps produced by intermittent irradiance *** order to achieve the desired objective,solutions based on storage systems or modifying the maximum power point tracking(mPPT)in perturb and observe(P&O)algorithms are commonly *** starting point in PRRC is the determination of the instantaneous power ramprate,and different methods have been proposed in the literature for its ***,the accuracy and computational speed of existing procedures can be improved,which may be critical in situations with rapid irradiance *** this paper,a decoupled photovoltaic power ramp-rate calculation method is presented,in which the effect of variable irradiance and the P&O algorithm are computed *** proposed method has been theoretically demonstrated and tested through simulation and experimental *** results show that it can improve the previous methods in terms of accuracy and computation *** validation with hardware-inthe-loop demonstrates the suitability of the proposed method for real-time applications,even in presence of noisy measurements.

关键词： Hardware-in-the-loop maximum power point tracking perturb and observe photovoltaic power ramp-rate control ramp-rate calculation method

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Optimal microgrid planning for enhancing ancillary service provision

引用

Journal of modern Power Systems and Clean Energy 2019年第4期7卷 862-875页

作者： sergio F.CONTRERAS Camilo A.CORTES Johanna m.A.mYRZIK Institute of Automation Technology University of BremenOtto-Hahn-Allee 1 NW1/M1050(70)28359 BremenGermany Department of Electrical and Electronics Engineering Universidad Nacional de ColombiaCarrera 30 Calle 45.Ciudad Universitaria Edificio 453Bogota′Colombia

microgrids have presented themselves as an effective concept to guarantee a reliable,efficient and sustainable electricity delivery during the current transition era from passive to active distribution ***,microgrids could offer effective ancillary services(AS)to the power utility,although this will not be possible before the traditional planning and operation methodologies are ***,a probabilistic multi-objective microgrid planning(POmmP)methodology is proposed in this paper to contemplate the large number of variables,multiple objectives,and different constraints and uncertainties involved in the microgrid *** planning methodology is based on the optimal size and location of energy distributed resources with the goal of minimizing the mismatch power in islanded mode,while the residual power for AS provision and the investment and operation costs of the microgrid in grid-connected mode are maximized and minimized,*** that purpose,probabilistic models and a true multi-objective optimization problem are implemented in the *** methodology is tested in an adapted PG&E 69-bus distribution system and the non-dominated sorting genetic algorithmⅡ(NSGA-Ⅱ)optimization method and an analytic hierarchy process for decision-making are used to solve the optimization problem.

关键词： microgrid Ancillary services(AS) Planning multi-objective optimization Decision-making

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Fast prediction of rain erosion in wind turbine blades using a data-based computational tool

引用

Journal of Hydrodynamics 2024年第3期36卷 504-518页

作者： Juan m.Gimenez sergio R.Idelsohn Eugenio Oñate Centre Internacional de mètodes Numèrics en Enginyeria(CImNE) Edifici C1 Campus Nord UPC C/Gran CapitàS/NBarcelonaSpain

Wind turbines(WTs)face a high risk of failure due to environmental factors like erosion,particularly in high-precipitation areas and offshore *** this paper we introduce a novel computational tool for the fast prediction of rain erosion damage on WT blades that is useful in operation and maintenance decision making *** approach is as follows:Pseudo-Direct Numerical Simulation(P-DNS)simulations of the droplet-laden flow around the blade section profile are employed to build a high-fidelity data set of impact statistics for potential operating *** this database as training data,a machine learning-based surrogate model provides the feature of the impact pattern over the 2-D section for given wind and rain *** this information,a fatigue-based model estimates the remaining lifetime and erosion damage for both homogeneous and coating-substrate blade *** prediction is done by quantifying the accumulated droplet impact energy and evaluating operative conditions over time periods for which the weather at the installation site is *** this work,we describe the modules that compose the prediction method,namely the database creation,the training of the surrogate model and their coupling to build the prediction ***,the method is applied to predict the remaining lifetime and erosion damage to the blade sections of a reference *** evaluate the reliability of the tool,several site locations(offshore,coastal,and inland),the coating material and the coating thickness of the blade are *** few minutes we are able to estimate erosion after many years of *** results are in good agreement with field observations,showing the promise of the new rain erosion prediction approach.

关键词： Wind turbine blades leading edge erosion fatigue Pseudo-Direct Numerical Simulation(P-DNS) machine learning eblader

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

multi-temporal NDVI analysis using UAV images of tree crowns in a northern mexican pine-oak forest

引用

Journal of Forestry Research 2023年第6期34卷 1855-1867页

作者： JoséLuis Gallardo-Salazar marcela Rosas-Chavoya marín Pompa-García Pablito marcelo López-serrano Emily García-montiel Arnulfo meléndez-Soto sergio Iván Jiménez-Jiménez Instituto de Investigaciones Agropecuarias y Forestales Universidad Michoacana de San Nicolás de Hidalgo(UMSNH)58330 MoreliaMichoacánMexico Programa Institucional de Doctorado en Ciencias Agropecuarias y Forestales Universidad Juárez del Estado de DurangoRío Papaloapan y Blvd.DurangoValle del Sur s/n34120 DurangoDurangoMéxico Facultad de Ciencias Forestales Universidad Juárez del Estado de DurangoRío Papaloapan y Blvd.DurangoValle del Sur s/n34120 DurangoDurangoMéxico Instituto de Silvicultura e Industria de la madera Universidad Juárez del Estado de DurangoBoulevard del Guadiana 501Ciudad UniversitariaTorre de Investigación34120 DurangoMéxico INIFAP-CENID RASPA Centro Nacional de Investigación Disciplinaria en Relación Agua-Suelo-Planta-Atmósfera Margen derecha canal Sacramento km 6.5Zona industrial35140 Gómez PalacioDurangoMexico

The use of unmanned aerial vehicles(UAV)for forest monitoring has grown significantly in recent years,providing information with high spatial resolution and temporal *** with multispectral sensors allow the use of indexes such as the normalized difference vegetation index(NDVI),which determines the vigor,physiological stress and photo synthetic activity of *** study aimed to analyze the spectral responses and variations of NDVI in tree crowns,as well as their correlation with climatic factors over the course of one *** study area encompassed a 1.6-ha site in Durango,mexico,where Pinus cembroides,Pinus engelmannii,and Quercus grisea *** images were acquired with UAV and information on meteorological variables was obtained from NASA/POWER *** ANOVA explored possible differences in NDVI among the three *** correlation was performed to identify the linear relationship between NDVI and meteorological *** differences in NDVI values were found at the genus level(Pinus and Quercus),possibly related to the physiological features of the species and their *** grisea had the lowest NDVI values throughout the year which may be attributed to its sensitivity to relative humidity and *** the use of UAV with a multispectral sensor for NDVI monitoring allowed genera differentiation,in more complex forest analyses hyperspectral and LiDAR sensors should be integrated,as well other vegetation indexes be considered.

关键词： multispectral images Normalized diff erence Vegetation index Phenology Unmanned aerial vehicles multitemporal analysis

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Critical minimum temperature limits xylogenesis and maintains treelines on the southeastern Tibetan Plateau

引用

Science Bulletin 2017年第11期62卷 804-812页

作者： Xiaoxia Li Eryuan Liang Jozica Gricar sergio Rossi Katarina Cufar Aaron m. Ellison Key Laboratory of Alpine Ecology and Biodiversity Key Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100101 China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing 100101 China Sloven ian Forestry Institute Department of Yield and Silviculture Vecna pot 2 S1-1000 Ljubljana Slovenia University of Quebec in Chicoutimi Departement des Sciences Fondamentales 555 Boulevard de l'Universite Chicoutimi (QC) G7H2B1 Canada Key Laboratory of Vegetation Restoration and management of Degraded Ecosystems Guangdong Provincial Key Laboratory of Applied Botany South China Botanical Garden Chinese Academy of Sciences Guangzhou 510650 China University of Ljubljana Biotechnical Faculty Department of Wood Science and Technology Jamnikarjeva 101 S1-1000 Ljubljana Slovenia Harvard Forest Harvard University 324 North Main St. Petersham MA 01366 USA

Physiological and ecological mechanisms that define treelines are still debated. It has been suggested that the absence of trees above the treeline is caused by low temperatures that limit growth. Thus, we hypothesized that there is a critical minimum temperature （CTmin） preventing xylogenesis at treeline. We tested this hypothesis by examining weekly xylogenesis across three and four growing seasons in two natural Smith fir （Abies georgei var. srnithii） treeline sites on the southeastern Tibetan Plateau. Despite differences in the timing of cell differentiation among years, minimum air temperature was the dominant climatic variable associated with xylem growth; the critical minimum temperature （CTmin） for the onset and end of xylogenesis occurred at 0.7 ±0.4 ℃. A process-based modelling chronology of tree-ring formation using this CTmin was consistent with actual tree-ring data. This extremely low CTmin permits Smith fir growing at treeline to complete annual xylem production and maturation and provides both support and a mechanism for treeline formation.

关键词： Cambial activity Critical minimum temperature Timberline Xylem Vaganov-Shashldn model

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

RANS feasibility study of using roughness to mimic transition strip effect on the crossflowseparation over a 6:1 prolate-spheroid

引用

Journal of Hydrodynamics 2019年第3期31卷 570-581页

作者： mojtaba m. Amiri marcelo A. Vitola sergio H. Sphaier, Paulo T. Esperanza Ocean Technology Laboratory (LabOceano-COPPE) Federal University of Rio de Janeiro Rio de Janeiro RJ 21941-907 Brazil

An axisymmetric body at incidence experiences the three-dimensional crossflow separation. This separation is attributed to the adverse circumferential pressure gradient. However, the separation pattern is also dependent upon the structure of the boundary layer. In this regard, utilization of transition strip devices in experiments on axisymmetric bodies may modify this structure, and consequently the crossflow separation pattern. The main objective of the present research is to mimic numerically the transition strip effect on the crossflow separation over a 6:1 prolate-spheroid up to a = 30° incidence and ReL = 4.2 x 10&. However, to avoid direct modeling of the strip, which would increase the computational cost, an attempt was made to add roughness over the body surface. To estimate the roughness that simulates closely the transition strip effect, three different roughness values were considered. The numerical model is based on RANS and a Reynolds stress turbulence model implemented in STARCCm+. The simulations have been evaluated based on the local and global variables and validated against the available experimental data. The results demonstrate the effectiveness of using a proper roughness value to mimic the transition strip effect. They also show the importance of modeling the transition strip effect, which is normally not taken into account, to capture the crossflow separation pattern.

关键词： Axisymmetric body crossflow separation transition strip device CFD RANS equations

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nickel phosphonate mOF as efficient water splitting photocatalyst

引用

Nano Research 2021年第2期14卷 450-457页

作者： Pablo Salcedo-Abraira sergio m.F.Vilela Artem A.Babaryk maria Cabrero-Antonino Pedro Gregorio Fabrice Salles sergio Navalon Hermenegildo Garcia Patricia Horcajada ImDEA Energy Advanced Porous Materials Unit(APMU)Avda.Ramon de Ia Sagra 3E 28935 MostolesMadridSpain Deparrtamento de Quimica Inorginica I.Fac.CC.Quimicas Universidad Complutense de MadridAvda.Complutense s/n28040 MadridSpain Departamento de Quimica and Instituto de Tecnologia Quimica(CSIC-UPV) Universitat Politecnica de ValenciaC/Camino de Veras/n46022 ValenciaSpain Institut Charles Gerhardt montpellier UMR 5253 CNRS UM ENSCMUniversite MontpellierPlace E.Bataillon34095 Montpellier Cedex 05France

A novel microporous two-dimensional(2D)Ni-based phosphonate metal-organic framework(mOF;denoted as IEF-13)has been successfully synthesized by a simple and green hydrothermal method and fully characterized using a combination of experimental and computational *** resolution by single-crystal X-ray diffraction reveals that IEF-13 crystallizes in the triclinic space group Pi having bi-octahedra nickel nodes and a photo/electroactive tritopic phosphonate ***,this material exhibits coordinatively unsaturated nickel(II)sites,free-P0_(3)H_(2)and-P0_(3)H acidic groups,a C0_(2)accessible microporosity,and an exceptional thermal and chemical ***,its in-deep optoelectronic characterization evidences a photoresponse suitable for *** this sense,the photocatalytic activity for challenging H_(2)generation and overall water splitting in absence of any co-catalyst using UV-Vis irradiation and simulated sunlight has been evaluated,constituting the first report for a phosphonate-mOF ***-13 is able to produce up to 2,200 fimol of H_(2)per gram using methanol as sacrificial agent,exhibiting stability,maintaining its crystal structure and allowing its *** more,170μmol of H_(2)per gram were produced using IEF-13 as photocatalyst in the absence of any co-catalyst for the overall water splitting,being this reaction limited by the 0_(2)*** present work opens new avenues for further optimization of the photocatalytic activity in this type of multifunctional materials.

关键词： metal-organic framework phosphonates photocatalysis water splitting

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acyclic Complexes and Gorenstein Rings

引用

Algebra Colloquium 2020年第3期27卷 575-586页

作者： sergio Estrada Alina Iacob Holly Zolt Departamento de matematicas Universidad de MurciaMurcia 30100Spain Department of mathematical Sciences Georgia Southern University StatesboroGA 30460-8093USA

For a given class of modules A,let A be the class of exact complexes having all cycles in A,and dw(A)the class of complexes with all components in *** by GL the class of Gorenstein injective *** prove that the following are equivalent over any ring R:every exact complex of injective modules is totally acyclic;every exact complex of Gorenstein injective modules is in every complex in dw(GL)is dg-Gorenstein *** analogous result for complexes of flat and Gorenstein flat modules also holds over arb计rary *** the ring is n-perfect for some integer n≥0,the three equivalent statements for flat and Gorenstein flat modules are equivalent with their counterparts for projective and projectively coresolved Gorenstein flat *** also prove the following characterization of Gorenstein *** R be a commutative coherent ring;then the following are equivalent:(1)every exact complex of FP-injective modules has all its cycles Ding injective modules;(2)every exact complex of flat modules is F-totally acyclic,and every R-modulc m such that m^(+)is Gorenstein flat is Ding injective;(3)every exact complex of injectives has all its cycles Ding injective modules and every R-module m such that is Gorenstein flat is Ding *** R has finite Krull dimension,statements(1)-(3)are equivalent to(4)R is a Gorenstein ring(in the sense of Iwanaga).

关键词： totally acyclic complex Gorenstein injective module Gorenstein projective module Gorenstein flat module Ding injective module

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Approximate Expressions to Evaluate the Performance in Butene-1 Purification Units

引用

Chinese Journal of Chemical Engineering 1998年第3期6卷 87-92页

作者： sergio P.Bressa Nestor O.Ardiaca Osvaldo m.martinez Guillermo F.Barreto Depto.de Ing.Qca. Fac.de Ing.U.N.L.P.l esq.47(1900)La PlataDepto.de Ing.Qca.Fac.de Ing.U.N.L.P.l esq.47(1900)La PlataDepto.de Ing.Qca.Fac.de Ing.U.N.L.P.l esq.47(1900)La PlataDepto.de Ing.Qca.Fac.de Ing.U.N.L.P.l esq.47(1900)La Plata

1 INTRODUCTIONSelective hydrogenatioll of small amounts of butynes and butadiene is industrially employedfor obtaining high purity butene-l used as co-monomer in the production of linear *** this purpose,the content o... 详细信息

关键词： selective hydrogenation butene-1 1 3-butadiene trickle bed reactor

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：