检索结果-南通市图书馆

Sediment balances in the Blue Nile River Basin

在线全文

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2014年第3期29卷 316-328页

作者： Yasir S.A.ALI Alessandra CROSATO Yasir A.MOHAMED Seifeldin H.ABDALLA nigel g.wright UNESCO-IHE Westvest 72601 DA Delftthe Netherlands and Hydraulics Research CenterMinistry of Water Resources and ElectricityP.O.Box 318Wad MedaniSudan UNESCO-IHE Westvest 72601 DA Delft and Profat Hydraulics Research CenterMinistry of Water Resources and Electricity School of Civil Engineering University of LeedsFaculty of EngineeringLeeds LS2 9JT.United Kingdom Water Resources Technical Organ Ministry of Water Resources and ElectricityKhartoumSudan UNESCO-IHE Westvest 72601 DA Delft and Research Associate at Civil Engineering and Geosciences Delft University of TechnologyStevin weg 12628 CN Delftthe Netherlands

Rapid population growth in the upper Blue Nile basin has led to fast land-use changes from natural forest to agricultural *** resulted in speeding up the soil erosion process in the highlands and increasing sedimentation further downstream in reservoirs and irrigation *** present,several dams are planned across the Blue Nile River in Ethiopia and the grand Ethiopian Renaissance Dam is currently under construction near the border with *** will be the largest hydroelectric power plant in *** objective of this paper is to quantify the river flows and sediment loads along the Blue Nile River *** Soil and Water Assessment Tool was used to estimate the water flows from un-gauged *** assess model performance,the estimated sediment loads were compared to the measured ones at selected *** the gauged sub-basins,water flows and sediment loads were derived from the available flow and sediment *** fill in knowledge gaps,this study included a field survey in which new data on suspended solids and flow discharge were collected along the Blue Nile and on a number of *** comparison between the results of this study and previous estimates of the sediment load of the Blue Nile River at El Deim,near the Ethiopian Sudanese border,show that the sediment budgets have the right order of magnitude,although some uncertainties *** gives confidence in the results of this study providing the first sediment balance of the entire Blue Nile catchment at the sub-basin scale.

关键词： Blue Nile basin Sediment balance Field data Rating curve SWAT model

Multiple effects of sediment transport and geomorphic processes within flood events:Modelling and understanding

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

International Journal of Sediment Research 2015年第04期 371-381页

作者： Mingfu guan nigel g.wright P.Andrew Sleigh University of Leeds

Flood events can induce considerable sediment transport which in turn influences flow *** study investigates the multiple effects of sediment transport in floods through modelling a series of hydraulic scenarios,including small-scale experimental cases and a full-scale glacial outburst flood.A non-uniform,layer-based morphodynamic model is presented which is composed of a combination of three modules:a hydrodynamic model governed by the two-dimensional shallow water equations involving sediment effects;a sediment transport model controlling the mass conservation of sediment;and a bed deformation model for updating the bed *** model is solved by a second-order godunov-type numerical *** the modelling of the selected sediment-laden flow events,the interactions of flow and sediment transport and geomorphic processes within flood events are *** is found that the inclusion of sediment transport increases peak flow discharge,water level and water depth in dam-break flows over a flat *** a partial dam breach,sediment material has a blockage effect on the flood *** comparison with the 'sudden collapse' of a dam,a gradual dam breach significantly delays the arrival time of peak flow,and the flow hydrograph is changed *** bed erosion and deposition occur within the rapid outburst flood,which scours the river channel *** is noted that the flood propagation is accelerated after the incorporation of sediment transport,and the water level in most areas of the channel is reduced.

关键词：

Microstructure and Mechanical Properties of Cold Metal Transfer Welding Similar and Dissimilar Aluminum Alloys

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2015年第6期28卷 715-724页

作者： Ahmed Elrefaey nigel g.Ross LKR Leichtmetallkompetenzzentrum Ranshofen gmbH Austrian Institute of Technology

Integrating structures made from aluminum alloys in automotive industry requires a large amount of joining. As a consequence, the properties of the joints have a significant influence on the overall performance of the whole structure. Robot cold metal transfer welding is a relatively new joining technique and has been used in this work to join 6082-T4 and 5182-O aluminum alloy sheets by using ER5356 and ER4043 filler metals. Microstructure characterization was performed by optical microscopy and energy dispersive X-ray spectroscopy, and the mechanical properties were measured by tensile and hardness tests. A correlation is made between welding variables, mechanical properties and the microstructure of welded joints. Results indicate that robot cold metal transfer welding provides good joint efficiency with high welding speed, good tensile strength, and ductility. Owing to the low heat input of robot cold metal transfer welding process, the heat affected zone microstructure was quite similar to base metals, and weld metal microstructure was the controlling factor of joint efficiency. The best performing were the 5182/5182 joints welded with ER5356 and these had mechanical property coefficients of 100%, 98%, and 85% for yield strength, ultimate tensile strength, and elongation, respectively.

关键词： Aluminum CMT Welding Microstructure Tensile property

Vegetation composition of old extensive green roofs(from 1980s germany)

在线全文

学校读者我要写书评

暂无评论

Ecological Processes 2014年第1期3卷 225-235页

作者： Christine E Thuring nigel Dunnett Department of Landscape Floor 9The Arts TowerWestern BankSheffieldSouth Yorkshire S102TNUK

Introduction:Since their development in the late 1970s in germany,extensive green roofs(EgR)have become increasingly popular as mitigation tools for urban environmental issues around the *** are planted with select species,which ensure consistent cover and performance over *** research presented herein is part of a systematic re-evaluation of EgR technology since the german industry ***:given the opportunity to access a small sample of old EgRs installed over 20 years ago in south-west germany,this research surveyed the vegetation and substrate with an interest in describing these parameters with time-through-space ***:Similar to previous studies,this preliminary work found correlations between roof age with vegetation(cover abundance and species diversity)and substrate properties(e.g.,depth,organic content,pH,and nutrients).Roof age had positive relationship with soil organic content(Corg),and negative relationships with substrate depth and soil *** soil variables are inter-related,as shallow acidic substrates create unfavourable conditions for decomposition and thereby the accumulation of *** variables correlated with EgR vegetation,suggesting a trend of simplified species composition over ***,Corg had a negative relationship with cover and species diversity of most life forms;only Sedum species had positive associations with ***:Considering the dynamics associated with shallow mineral substrates,and the greater floristic diversity of younger roofs,simple Sedum-based vegetation may represent a steady state for conventional EgRs.

关键词： Biodiversity Extensive green roofs germany Long-term performance Plant life forms Sedum Species diversity Substrate depth

A simpliied fatigue assessment method for transverse illet welded joints

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2017年第2期30卷 198-208页

作者： Wei Shen Renjun Yan nigel Barltrop Kai Qin Feng He Key Laboratory of High Performance Ship Technology (Wuhan University of Technology) Ministry of EducationWuhan 430063 China State Key Laboratory of Ocean Engineering Shanghai University Tong University Shanghai 200240 China Department of Naval Architecture and Marine Engineering University of Strathclyde Glasgow G4OLZ UnitedKingdom

Under the as-welded condition the fatigue crack initiation period was considered nonexistent and Linear Elastic Fracture Mechanics（LEFM） was used to calculate fatigue strength for a range of weld geometries. Fracture mechanics assessment of welded joints requires accurate solutions for stress intensity factor（SIF）. However, the solutions for the SIF of complex welded joints are dificult to determine due to the complicated correction factors. Three methods for SIF prediction are discussed on illet welded specimens containing continuous or semi-elliptical surface cracks, including the traditional correction method Mk, the approximate correction method Kt, and the suggested additional crack size method（ac＋ae）.The new additional crack parameter ae is used to replace the stress concentration effect of weld proile Mk, which simpliies the calculation process. Experimental results are collected to support fatigue strength assessment of the additional crack size method.

关键词： Fillet welded joints Stress intensity factor(SIF) Additional crack size(ae) Fatigue strength

genetic Diversity and Population Structure Analysis of Barley Landraces from Shanghai Region Using genotyping-by-Sequencing

在线全文

学校读者我要写书评

暂无评论

Phyton-International Journal of Experimental Botany 2023年第4期92卷 1275-1287页

作者： Luli Li nigel g.Halford Huihui Wang Yingjie Zong Zhenzhu guo Ruiju Lu Chenghong Liu Zhiwei Chen Shanghai Key Laboratory of Agricultural genetics and Breeding Biotechnology Research InstituteShanghai Academy of Agricultural SciencesShanghai201106China College of Fisheries and Life Science Shanghai Ocean UniversityShanghai201306China Rothamsted Research HarpendenAL52JQUK Qingdao OE Biotechnology Company Limited Qingdao266100China

Barley(Hordeum vulgare L.)is an important economic crop for food,feed and industrial raw *** the present research,112 barley landraces from the Shanghai region were genotyped using genotyping-by-sequencing(gBS),and the genetic diversity and population structure were *** results showed that 210,268 Single Nucleotide Polymorphisms(SNPs)were present in total,and the average poly-morphism information content(PIC)was *** diversity and population structure analyses suggested that these barley landraces were differentiated and could be divided into three sub-groups,with morphological traits of row-type and adherence of the hulls the main distinguishing factors between *** with similar or duplicated names were also investigated according to their genetic backgrounds and seed *** study provided valuable information on barley landraces from the Shanghai region,and showed that all these barley landraces should be protected and used for future breeding programs.

关键词： Hordeum vulgare L cluster analysis population structure SNP markers

COMPARISON OF OPTICAL POLARIMETRY AND DIFFUSION TENSOR MR IMAgINg FOR ASSESSINg MYOCARDIAL ANISOTROPY

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 Innovative Optical Health Sciences 2010年第2期3卷 109-121页

作者： MARIKA A.WALLENBURg MIHAELA POP MICHAEL F.g.WOOD NIRMALYA gHOSH gRAHAM A.wright I.ALEX VITKIN Ontario Cancer Institute Division of Biophysics and Bioimaging University Health Network and University of Toronto Department of Medical Biophysics610 University Avenue TorontoOntarioCanada M5G 2M9 Department of Medical Biophysics University of Toronto Sunnybrook Health Sciences Center2075 Bayview Avenue TorontoONCanadaM5N 3M5 IISER Kolkata Mohanpur CampusP.O.BCKV Campus Main Office Mohanpur 741252West BengalIndia Ontario Cancer Institute Division of Biophysics and Bioimaging University Health Network and University of Toronto Departments of Medical Biophysics and Radiation Oncology 610 University AvenueTorontoOntarioCanada M5G 2M9

We have recently proposed an optical method for assessing heart structure that uses polarized light measurement of birefringence as an indicator of tissue *** highly aligned nature of healthy cardiac muscle tissue has a detectable effect on the polarization of light,resulting in a measurable phase shift(“retardance”).When this organized tissue structure is perturbed,for example after cardiac infarction(heart attack),scar tissue containing disorganized collagen is formed,causing a decrease in the measured retardance ***,these are dependent not only on tissue anisotropy,but also on the angle between the tissue’s optical anisotropy direction and the beam interrogating the *** remove this experimental ambiguity,we present a method that interrogates the sample at two different incident beam angles,thus yielding enough information to uniquely determine the true magnitude and orientation of the tissue optical *** use an infarcted porcine heart model to compare these polarimetryderived anisotropy metrics with those obtained with diffusion tensor magnetic resonance imaging(DT-MRI).The latter yields the anisotropy and the direction of tissue water diffusivity,providing an independent measure of tissue *** optical and MR results are thus directly compared in a common ex vivo biological model of interest,yielding reasonable agreement but also highlighting some technique-specific differences.

关键词： Birefringence Mueller matrix decomposition fractional anisotropy diffusion tensor magnetic resonance imaging myocardial infarction

Ciliated hepatic foregut cyst:an increasingly diagnosed condition

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2008年第6期7卷 581-589页

作者： Sharad Sharma Amanda g.Dean Ayumi Corn Vivek Kohli Harlan I wright Anthony Sebastian Nicolas Jabbour Methodist University Hospital Transplant Institute 1265 Union Avenue Nazih Zuhdi Transplant Institute 3300 North West Expressway

BACKgROUND:Ciliated foregut cysts of the liver are rare, with only 96 cases diagnosed since the first description in *** are being increasingly diagnosed recently;the majority of the cases have been reported in the last 15 years. Although they bear a close resemblance to the simple cyst of the liver which has essentially a benign course,ciliated hepatic foregut cysts(CHFCs)can progress to malignancy with devastating *** is imperative that this group of conditions be diagnosed and treated adequately. DATA SOURCES:This review includes discussion of the data from all the 96 reported cases from English and non-English *** of the incidence rates, embryogenesis,growth,clinical features,risk of malignancy and the prognosis are highlighted *** roles of various diagnostic modalities including ultrasound, CT,MRI,fine needle aspiration cytology(FNAC), immunohistochemistry and surgery are further discussed. RESULTS:The mean age of patients with CHFC was 48± 12 *** male/female ratio was 1.1∶*** majority of patients with CHFC(62%)were asymptomatic,and the common mode of presentation was right upper abdominal *** cysts occurred in the left lobe in 51 patients, with sole location in segmentⅣin 44,and in the right lobe in *** average size of the cysts was 3.6±2.12 cm. The majority of the cysts were unilocular,and only 7 cases were *** contents were described as viscous or mucinous in 73 patients,whereas bilious fluid was noted in *** cysts having squamous carcinoma were cited in 3 patients,and 2 had extensive squamous metaplasia without *** had benign histopathology. CONCLUSIONS:Clinicians have become increasingly aware of *** alone is not diagnostic per se, but when considered in the context of the global picture does provide important clues to the *** is diagnostic by the presence of the ciliated columnar aspirate but lacks *** presentation is usua

关键词： ciliated hepatic foregut cyst squamous cell carcinoma cystic liver disease

Observation or resection of pancreatic intraductal papillary mucinous neoplasm:An ongoing tug of war

在线全文

学校读者我要写书评

暂无评论

World Journal of gastrointestinal Oncology 2019年第12期11卷 1092-1100页

作者： Jan Rune Aunan nigel B.Jamieson Kjetil Sφreide Department of gastrointestinal Surgery HPB UnitStavanger University HospitalStavanger 4068Norway Wolfson Wohl Cancer Research Centre Institute of Cancer SciencesUniversity of GlasgowGlasgow G611BDUnited Kingdom West of Scotland Pancreatic Unit Glasgow Royal InfirmaryGlasgow G40SFUnited Kingdom gastrointestinal Translational Research Unit Laboratory for Molecular MedicineStavanger University HospitalStavanger 4068Norway Department of Clinical Medicine University of BergenBergen 5003Norway

An increasing number of patients are being referred to pancreatic centres around the world due to often incidentally discovered cystic neoplasms of the *** evaluation and management of pancreatic cystic neoplasms is a controversial topic and with existing guidelines based on a lack of strong evidence there is discordance between centres and guidelines with regard to when to offer surgery and when to favour *** frequency,duration and modality of surveillance is also controversial as this is resource-consuming and must be balanced against the perceived benefits and risks *** there is consensus that the risk of malignancy should be balanced against the lifeexpectancy and comorbidities,the indications for surgery and surveillance strategies vary among the ***,the tug of war between surveillance or resection *** we discuss the recommendations from guidelines with further accumulating data and emerging reports on intraductal papillary mucinous neoplasm in the literature.

关键词： Neoplasia Pancreatic cancer Pancreatic cyst Diagnosis Resection Surveillance Mutation Biomarker