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computational fluid dynamics simulation of the wind flow over an airport terminal building

Journal of Zhejiang University-science A(Applied Physics & Engineering) 2010年第6期11卷 389-401页

作者： chun-ho LIU Dennis Y.c.LEUNG alex c.s.man P.W.cHAN Department of Mechanical Engineering The University of Hong Kong Hong Kong Observatory

Turbulence in the wake generated by wind flow over buildings or obstacles may produce complex flow patterns in downstream *** include the recirculating flow and wind deficit areas behind an airport terminal building and their potential impacts on the aircraft landing on nearby runways.A computational fluid dynamics(cFD) simulation of the wind flow over an airport terminal building was performed in this study of the effect of the building wake on landing *** normal meteorological conditions,the studied airport terminal building causes limited effects on landing aircraft because most of the aircraft have already landed before entering the turbulent wake *** simulating the approach of a tropical cyclone,additional cFD sensitivity tests were performed to study the impacts of building wake under extreme meteorological *** was found that,in a narrow range of prevalent wind directions with wind speeds larger than a certain threshold value,a substantial drop in wind speed(>3.6 m/s) along the glide path of aircraft was observed in the building *** cFD results also showed that under the most critical situation,a drop in wind speed as large as 6.4 m/s occurred right at the touchdown point of landing aircraft on the runway,an effect which may have a significant impact on aircraft *** study indicated that a comprehensive analysis of the potential impacts of building wake on aircraft operations should be carried out for airport terminals and associated buildings in airfields to ensure safe aviation operation under all meteorological conditions and to facilitate implementation of precautionary measures.

关键词： Aviation safety Building aerodynamics computational fluid dynamics (cFD) k-e turbulence model Tropicalcyclone

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Brain-derived neurotrophic factor signaling in the neuromuscular junction during developmental axonal competition and synapse elimination

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Neural Regeneration Research 2025年第2期20卷 394-401页

作者： Josep Tomàs Víctor cilleros-Mañé Laia Just-Borràs Marta Balanyà-segura Aleksandra Polishchuk Laura Nadal Marta Tomàs carolina silvera-simón manel M.santafé Maria A.Lanuza Unitat d’Histologia i Neurobiologia(UHNeurob) Facultat de Medicina i Ciències de la SalutUniversitat Rovira i VirgiliReusSpain

During the development of the nervous system,there is an overproduction of neurons and *** competition between neighboring nerve endings and synapses performing different activity levels leads to their elimination or *** have extensively studied the involvement of the brain-derived neurotrophic factor-Tropomyosin-related kinase B receptor neurotrophic retrograde pathway,at the neuromuscular junction,in the axonal development and synapse elimination process versus the synapse *** purpose of this review is to describe the neurotrophic influence on developmental synapse elimination,in relation to other molecular pathways that we and others have found to regulate this *** particular,we summarize our published results based on transmitter release analysis and axonal counts to show the different involvement of the presynaptic acetylcholine muscarinic autoreceptors,coupled to downstream serine-threonine protein kinases A and c(PKA and PKc)and voltage-gated calcium channels,at different nerve endings in developmental *** dynamic changes that occur simultaneously in several nerve terminals and synapses converge across a postsynaptic site,influence each other,and require careful studies to individualize the mechanisms of specific *** describe an activity-dependent balance(related to the extent of transmitter release)between the presynaptic muscarinic subtypes and the neurotrophin-mediated TrkB/p75NTR pathways that can influence the timing and fate of the competitive interactions between the different axon *** downstream displacement of the PKA/PKc activity ratio to lower values,both in competing nerve terminals and at postsynaptic sites,plays a relevant role in controlling the elimination of supernumerary ***,calcium entry through L-and P/Q-subtypes of voltage-gated calcium channels(both channels are present,together with the N-type channel in developing nerve terminals)contributes to red

关键词： acetylcholine release adenosine receptors axonal competition brain-derived neurotrophic factor calcium channels motor end-plate muscarinic acetylcholine receptors postnatal synapse elimination serine kinases tropomyosin-related kinase receptorB

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Improvement strategies for Ni-based alcohol steam reforming catalysts

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Journal of Energy chemistry 2023年第11期86卷 447-479,I0010页

作者： alex Desgagnés Ommolbanin Alizadeh sahraei Maria c.Iliuta UniversitéLaval Département de Génie Chimique1065 Avenue de la MédecineQuébecQC G1V 0A6Canada

steam reforming(sR)of fossil methane is already a well-known,documented and established expertise in the industrial sector as it accounts for the vast majority of global hydrogen *** a sustainable development perspective,hydrogen production by sR of biomass-derived feedstock represents a promising alternative that could help to lower the carbon footprint of the traditional *** this regard,bio-alcohols such as methanol,ethanol or glycerol are among the attractive candidates that could serve as green hydrogen carriers as they decompose at relatively low temperatures in the presence of water compared to methane,allowing for improved H_(2)***,significant challenges remain regarding the activity and stability of nickel-based catalysts,which are most widely used in alcohol sR processes due to their affordability and ability to break c–c,O–H and c–H bonds,yet are prone to rapid deactivation primarily caused by coke deposition and metal particle *** this state-of-the-art review,a portfolio of strategies to improve the performance of Ni-based catalysts used in alcohol sR processes is unfolded with the intent of pinpointing the critical issues in catalyst *** examination of the literature reveals that the efforts tackling these recurring issues can be directed at the active metal,either by tuning Ni dispersion and Ni-support interactions or by targeting synergistic effects in bimetallic systems,while others focus on the support,either by modifying acid-base character,oxygen mobility,or by embedding Ni in specific crystallographic *** review provides a very useful tool to orient future work in catalyst development.

关键词： H2 production Alcohol steam reforming Ni-based catalysts catalyst development sintering coke formation

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Mapping land subsidence over the eastern Beijing city using satellite radar interferometry

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International Journal of Digital Earth 2018年第5期11卷 504-519页

作者： Zheyuan Du Linlin Ge alex Hay-man Ng Li Xiaojing Liyuan Li Geoscience and Earth Observing system Group(GEOs) School of Civil and Environmental EngineeringUNSW AustraliaSydneyAustralia Department of surveying Engineering Guangdong University of TechnologyGuangzhouPeople’s Republic of China

Beijing city has suffered from groundwater-induced subsidence since the late 1930s and the over-exploration of groundwater could lead to subsidence as much as−12.0 cm yr−*** studies on the ground deformation at Beijing city mainly focused on the period before the year of 2014 when a mega-engineering project was launched to reduce water shortage in *** study the most recent ground deformation,19 L-band ALOs-1 PALsAR images(June 2007–January 2011),24 c-band sentinel-1 sAR images(June 2015–November 2016)together with 9 ALOs-2 PALsAR acquisitions(september 2014–February 2017)were analysed in this *** measurements were exploited to verify the ALOs-1-based time series InsAR(Ts-InsAR)result while sentinel-1 and ALOs-2 result were cross-verified with each ***,the whole study area was divided into four sub-zones,and the result indicated that the subsidence rates over five townships,cuigezhuan,Jinzhan,Liyuan,songzhuang and Yanjiao were accelerating and more attentions should be *** the contrary,the town centre of Douge Zhuang township experienced a decreasing trend between these two ***,the time series measurements with respect to five selected measurement points and the profile line along the subsidence hot spots were analysed.

关键词： subsidence Beijing groundwater sAR interferometry

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Monitoring of ground deformation in Liulin district,china using InsAR approaches

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International Journal of Digital Earth 2018年第3期11卷 264-283页

作者： Zheyuan Du Linlin Ge alex Hay-man Ng Xiaojing Li Liyuan Li Geoscience and Earth Observing system Group(GEOs) School of Civil and Environmental EngineeringUNSW AustraliaSydneyAustralia Department of surveying Engineering Guangdong University of TechnologyGuangzhouPeople’s Republic of China

coalbed methane(cBM)exploration generally refers to a technique that extracts natural gas from coal *** development of cBM in Liulin,china,has experienced a significantly growth period during the past two *** research mainly focused on the coal geological background or cBM technique itself,while time series InsAR(Ts-InsAR)technique was conducted in this work to study the potential land deformation induced by cBM extraction from 2003 to *** total,21 ALOs-1 PALsAR images(acquired from 22 December 2006 to 2 January 2011)and 14 ENVIsAT AsAR scenes(captured between 29 October 2003 and 7 November 2007)were *** Ts-InsAR outcome revealed that the annual deformation rates were ranging from 15 to−40 mm yr−1 over the study *** the time series deformation evolutions were analysed over 8 cBM sites(No.4 coal seam)out of 20,and the subsidence rates between 1.9 and−6.5 mm yr−1 were *** addition,the average subsidence rate and standard deviation among these eight measurements were−3.0 and 2.6 mm yr−1 respectively,suggesting that these cBM extraction sites were quite stable and no obvious subsidence had been observed during this eight-year period.

关键词： Ts-InsAR subsidence measurement cBM

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searching For(2+1)-dimensional nonlinear Boussinesq equation from(1+1)-dimensional nonlinear Boussinesq equation

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communications in Theoretical Physics 2023年第7期75卷 58-61页

作者： man Jia s Y Lou school of Physical science and Technology Ningbo UniversityNingbo315211China

A novel(2+1)-dimensional nonlinear Boussinesq equation is derived from a(1+1)-dimensional Boussinesq equation in nonlinear schr?dinger type based on a deformation *** integrability of the obtained(2+1)-dimensional Boussinesq equation is guaranteed by its Lax pair obtained directly from the Lax pair of the(1+1)-dimensional Boussinesq *** of the effects of the deformation,the(2+1)-dimensional Boussinesq equation admits a special travelling wave solution with a shape that can be deformed to be asymmetric and/or multivalued.

关键词： (2+1)-dimensional Boussinesq equation deformation algorithm lax integrable an implicit travelling wave solution

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Plant communities and Factors Responsible for Vegetation Pattern in an Alpine Area of the Northwestern Himalaya

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Journal of Mountain science 2011年第6期8卷 817-826页

作者： man s.RANA s.s.sAmanT Y.s.RAWAT Department of Plant science Government Degree College G.B.Pant Institute of Himalayan Environment & Development Department of Botany D.S.B.CampusKumaun University

The study intended to describe the alpine vegetation of a protected area of the northwestern Himalaya and identify the important environmental variables responsible for species *** placed random plots covering different habitats and altitude to record species composition and environmental *** was classified using hierarchical cluster analysis and vegetation-environment relationships were evaluated with canonical correspondence *** communities,each in alpine shrub and meadows were delineated and well justified in the ordination *** species for the different communities were *** species richness and diversity were found in community IV among shrub communities and community II among the *** environmental variables explained 61.5% variation in shrub vegetation and 59.8% variation in *** variables explained higher variability (～35%) than spatial variables (～21%) in both shrubs and ***,among the spatial variables and carbon/nitrogen ratio and nitrogen among the soil variables explained maximum *** 40% variations left *** and species diversity among the other variables had significant correlation with ordination *** showed that altitude and c/N ratio played a significant role in species *** sampling efforts and inclusion of other non-studied variables are also suggested for better understanding.

关键词： species diversity Indicator species Environmental variable Ordination Explainedvariation

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Evolution of seismic risk management for insurance over the past 30 years

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Earthquake Engineering and Engineering Vibration 2018年第1期17卷 11-18页

作者： Haresh c.shah Weimin Dong Pane stojanovski alex chen stanford University CA USA Risk management solutions Inc Newark CA USA Asia Risk Transfer solutions Pte Ltd Singapore DWMconsulting Palo Alto CA USA Institute for catastrophe Risk management Nanyang Technological University Singapore cat Risk Reasearch LLC-Cupertino CA USA

During the past 30 years, there has been spectacular growth in the use of risk analysis and risk management tools developed by engineers in the financial and insurance sectors. The insurance, the reinsurance, and the investment banking sectors have enthusiastically adopted loss estimation tools developed by engineers in developing their business strategies and for managing their financial risks. As a result, insurance/reinsurance strategy has evolved as a major risk mitigation tool in managing catastrophe risk at the individual, corporate, and government level. This is particularly true in developed countries such as Us, Western Europe, and Japan. Unfortunately, it has not received the needed attention in developing countries, where such a strategy for risk management is most needed. Fortunately, in the last five years, there has been excellent focus in developing ＂Insur Tech＂ tools to address the much needed ＂Insurance for the Masses＂, especially for the Asian Markets. In the earlier years of catastrophe model development, risk analysts were mainly concerned with risk reduction options through engineering strategies, and relatively little attention was given to financial and economic strategies. such state-of-affairs still exists in many developing countries. The new developments in the science and technologies of loss estimation due to natural catastrophes have made it possible for financial sectors to model their business strategies such as peril and geographic diversification, premium calculations, reserve strategies, reinsurance contracts, and other underwriting tools. These developments have not only changed the way in which financial sectors assess and manage their risks, but have also changed the domain of opportunities for engineers and *** paper will address the issues related to developing insurance/reinsurance strategies to mitigate catastrophe risks and describe the role catastrophe risk insurance and reinsurance has played in managing finan

关键词： catastrophe risk management loss estimation risk modeling insurance for the masses

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Volcano video data characterized and classified using computer vision and machine learning algorithms

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Geoscience Frontiers 2020年第5期11卷 1789-1803页

作者： alex J.c.Witsil Jeffrey B.Johnson Department of Geosciences Boise State UniversityBoiseIDUSA

Video cameras are common at volcano observatories,but their utility is often limited during periods of crisis due to the large data volume from continuous acquisition and time requirements for manual *** cameras to serve as effective monitoring tools,video frames must be synthesized into relevant time series signals and further analyzed to classify and characterize observable *** this study,we use computer vision and machine learning algorithms to identify periods of volcanic activity and quantify plume rise velocities from video *** were collected at Villarrica Volcano,chile from two visible band cameras located^17 km from the vent that recorded at 0.1 and 30 frames per second between February and April *** these two months,Villarrica exhibited a diverse range of eruptive activity,including a paroxysmal eruption on 3 *** to and after the eruption,activity included nighttime incandescence,dark and light emissions,inactivity,and periods of cloud *** quantify the color and spatial extent of plume emissions using a blob detection algorithm,whose outputs are fed into a trained artificial neural network that categorizes the observable activity into five *** shifts from primarily nighttime incandescence to ash emissions following the 3 March paroxysm,which likely relates to the reemergence of the buried lava *** periods exhibiting plume emissions are further analyzed using a row and column projection algorithm that identifies plume onsets and calculates apparent plume horizontal and vertical rise *** onsets are episodic,occurring with an average period of^50 s and suggests a puffing style of degassing,which is commonly observed at ***,the lack of clear acoustic transients in the accompanying infrasound record suggests puffing may be controlled by atmospheric effects rather than a degassing regime at the *** presented here offer a generalized toolset for volcano monito

关键词： Volcano monitoring Plume exit velocity Volcano webcam Image processing Machine learning Villarrica

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Automated segmentation of Left Ventricle Using Local and Global Intensity Based Active contour and Dynamic Programming

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International Journal of Automation and computing 2018年第6期15卷 673-688页

作者： G.Dharanibai Anupama chandrasekharan Zachariah c.alex school of Electronics Engineering Vellore Institute of Technology (VIT) University Department of Radiology Sri Ramachandra University

The aim of this work is to develop an improved region based active contour and dynamic programming based method for accurate segmentation of left ventricle （LV） from multi-slice cine short axis cardiac magnetic resonance （MR） images. Intensity inhomogeneity and weak object boundaries present in MR images hinder the segmentation accuracy. The proposed active contour model driven by a local Gaussian distribution fitting （LGDF） energy and an auxiliary global intensity fitting energy improves the accuracy of endocardial boundary detection. The weightage of the global energy fitting term is dynamically adjusted using a spatially varying weight function. Dynamic programming scheme proposed for the segmentation of epicardium considers the myocardium probability map and a distance weighted edge map in the cost matrix. Radial distance weighted technique and conical geometry are employed for segmenting the basal slices with left ventricle outflow tract （LVOT） and most apical slices. The proposed method is validated on a public dataset comprising 45 subjects from medical image computing and computer assisted interventions （MIccAI） 2009 segmentation challenge. The average percentage of good endocardial and epicardial contours detected is about 99%, average perpendicular distance of the detected good contours from the manual reference contours is 1.95 mm, and the dice similarity coefficient between the detected contours and the reference contours is 0.91. correlation coefficient and the coefficient of determination between the ejection fraction measurements from manual segmentation and the automated method are respectively 0.9781 and 0.9567, for LV mass these values are 0.9249 and 0.8554. statistical analysis of the results reveals a good agreement between the clinical parameters determined manually and those estimated using the automated method.

关键词： cardiovascular magnetic resonance left ventricle endocardium epicardium myocardium segmentation active contour dynamic programming.

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