检索结果-南通市图书馆

Three-way Subsynchronous Torsional Interactions Between LCC HVDC,MMC HVDC and a Thermal Generator

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

现代电力系统与清洁能源学报(英文) 2023年第4期11卷 1331-1340页

作者： Stefan Kovacevic Dragan Jovcic Pierre Rault Olivier Despouys School of Engineering University of AberdeenAberdeen AB243UEU.K. Réseau de Transport d’Électricité ParisFrance

This paper performs a study on three-way subsynchronous torsional interactions(SSTI)between a hybrid dual-infeed high-voltage direct current(HVDC)system and a nuclear *** test case is based on the French IFA2000 line commutated converter(LCC)HVDC(2 GW)and the new Eleclink modular multilevel converter(MMC)HVDC(1 GW)interacting with the Gravelines generator(1 GW).The analysis is performed by the means of the eigenvalue stability assessment on an analytical model,while the accuracy of the conclusions is verified using the detailed non-linear electromegnetic transient program(EMTP)*** study shows that the dual-infeed system may introduce higher risk of the SSTI compared with the point-to-point HVDC *** shows that MMC operating as static synchronous compensator(STATCOM)may further reduce the torsional damping at 6.3 Hz *** conclusion may be unexpected since it is known fact from literature that STATCOM has a beneficial impact on the transient performance of *** studies show that in a sequential HVDC loading,it may be beneficial to load the MMC HVDC ***,the risk of the SSTI may be minimized by changing HVDC controller gains,in particular,by increasing phaselocked-loop(PLL)gains on the LCC rectifier.

关键词： Subsynchronous torsional interaction(SSTI) eigenvalue stability hybrid dual-infeed high-voltage direct current(HVDC) line commutated converter(LCC) modular multilevel converter(MMC) nuclear generator

Resistant starch: Implications of dietary inclusion on gut health and growth in pigs:a review

在线全文

学校读者我要写书评

暂无评论

Journal of Animal Science and Biotechnology 2022年第3期13卷 613-627页

作者： Felina P.Y.Tan Eduardo Beltranena Ruurd T.Zijlstra Department of Agricultural Food and Nutritional ScienceUniversity of AlbertaEdmontonAB T6G 2P5Canada

Starch from cereal grains,pulse grains,and tubers is a major energy substrate in swine rations constituting up to 55%of the *** pigs,starch digestion is initiated by salivary and then pancreaticα-amylase,and has as final step the digestion of disaccharides by the brush-border enzymes in the small intestine that produce monosaccharides(glucose)for *** starch(RS)is the proportion of starch that escapes the enzymatic digestion and absorption in the small *** undigested starch reaches the distal small intestine and hindgut for microbial fermentation,which produces short-chain fatty acids(SCFA)for *** in turn,influence microbial ecology and gut health of *** fermentative metabolites exert their benefits on gut health through promoting growth and proliferation of enterocytes,maintenance of intestinal integrity and thus immunity,and modulation of the microbial community in part by suppressing the growth of pathogenic bacteria while selectively enhancing beneficial ***,RS has the potential to confer prebiotic effects and may contribute to the improvement of intestinal health in pigs during the post-weaning *** these benefits to the well-being of pigs,RS has a contradictory effect due to lower energetic efficiency of fermented *** starch absorption *** varying amount and type of RS interact differently with the digestion process along the gastrointestinal tract affecting its energy efficiency and host physiological responses including feed intake,energy metabolism,and feed *** of research indicate that the use of RS as prebiotic may improve gut health and thereby,reduce the incidence of post-weaning diarrhea(PWD)and associated *** review summarizes our current knowledge on the effects of RS on microbial ecology,gut health and growth performance in pigs.

关键词： Growth performance Gut health Resistant starch Swine

Study of vibrating foundations considering soil-pile-structure interaction for practical applications

在线全文

学校读者我要写书评

暂无评论

Earthquake Engineering and Engineering Vibration 2008年第3期7卷 321-327页

作者： Han Yingcai Fluor Calgary AB Canada

An investigation of soil-pile-structure interaction is carried out, based on a large reciprocating compressor installed on an elevated concrete foundation （table top structure）. A practical method is described for the dynamic analysis, and compared with a 3D finite element （FE） model. Two commercial software packages are used for dynamic analysis considering the soilpile-structure interaction （SPSI）. Stiffness and damping of the pile foundation are generated from a computer program, and then input into the FE model. To examine the SPSI thoroughly, three cases for the soil, piles and superstructure are considered and compared. In the first case, the interaction is fully taken into account, that is, both the superstructure and soil-pile system are flexible. In the second case, the superstructure is flexible but fixed to a rigid base, with no deformation in the base （no SSI）. In the third case, the dynamic soil-pile interaction is taken into account, but the table top structure is assumed to be rigid. From the comparison beteen the results of these three cases some conclusions are made, which could be helpful for engineering practice.

关键词： soil-pile-structure interaction soil dynamics structural dynamics vibrating foundation

Bayesian modeling of dynamic behavioral change during an epidemic

在线全文

学校读者我要写书评

暂无评论

Infectious Disease Modelling 2023年第4期8卷 947-963页

作者： Caitlin Ward Rob Deardon Alexandra M.Schmidt Division of Biostatistics University of MinnesotaMinneapolisMNUSA Faculty of Veterinary Medicine University of CalgaryCalgaryABCanada Department of Mathematics and Statistics University of CalgaryCalgaryABCanada Department of Epidemiology Biostatisticsand Occupational HealthMontrealQCCanada

For many infectious disease outbreaks,the at-risk population changes their behavior in response to the outbreak severity,causing the transmission dynamics to change in *** change is often ignored in epidemic modeling efforts,making these models less useful than they could *** address this by introducing a novel class of datadriven epidemic models which characterize and accurately estimate behavioral *** proposed model allows time-varying transmission to be captured by the level of“alarm”in the population,with alarm specified as a function of the past epidemic *** investigate the estimability of the population alarm across a wide range of scenarios,applying both parametric functions and non-parametric functions using splines and Gaussian *** model is set in the data-augmented Bayesian framework to allow estimation on partially observed epidemic *** benefit and utility of the proposed approach is illustrated through applications to data from real epidemics.

关键词： Bayesian inference Compartmental model SIR SEIR Transmission modeling

Can changes in midsole bending stiffness of shoes affect the onset of joint work redistribution during a prolonged run?

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

Journal of Sport and Health Science 2022年第3期11卷 293-302页

作者： Sasa Cigoja Jared R.Fletcher Benno M.Nigg Human Performance Laboratory Faculty of KinesiologyUniversity of CalgaryCalgaryAB T2N 1N4Canada Department of Health and Physical Education Mount Royal UniversityCalgaryAB T3E 6K6Canada

Purpose This study aimed to investigate if changing the midsole bending stiffness of athletic footwear can affect the onset of lower limb joint work redistribution during a prolonged *** Fifteen trained male runners(10-km time ofabolic cost when running in stiff *** results contribute to the notion that footwear with increased stiffness likely results in reductions in metabolic cost by delaying joint work redistribution from distal to proximal joints.

关键词： Fatigue Footwear Mechanics Performance Running

GIScience research challenges for realizing discrete global grid systems as a Digital Earth

在线全文

学校读者我要写书评

暂无评论

Big Earth Data 2022年第3期6卷 358-379页

作者： Majid Hojati Colin Robertson Steven Roberts Chiranjib Chaudhuri Department of Geography and Environmental Studies Wilfrid Laurier UniversityWaterlooONCanada Coldwater Laboratory University of SaskatchewanCanmoreABCanada

Increasing data resources are available for documenting and detecting changes in environmental,ecological,and socioeconomic ***,data are distributed across a wide variety of sources(*** silos)and published in a variety of formats,scales,and semantic representations.A key issue,therefore,in building systems that can realize a vision of earth system monitoring remains data *** global grid systems(DGGSs)have emerged as a key technology that can provide a common multi-resolution spatial fabric in support of Digital Earth ***,DGGSs remain in their infancy with many technical,conceptual,and operational *** renewed interest in DGGS brought on by a recently proposed standard,the demands of big data,and growing needs for monitoring environmental changes across a variety of scales,we seek to highlight current challenges that we see as central to moving the field(s)and technologies of DGGS *** each of the identified challenges,we illustrate the issue and provide a potential solution using a reference DGGS *** articulation of these challenges,we hope to identify a clear research agenda,expand the DGGS research footprint,and provide some ideas for moving forward towards a scaleable Digital Earth *** such challenges helps the GIScience research community to achieve the real benefits of DGGS and provides DGGS an opportunity to play a role in the next generation of GIS.

关键词： DGGS discrete global grid systems GIScience Digital Earth

A new approach for determining GND and SSD densities based on indentation size effect:An application to additive-manufactured Hastelloy X

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

Journal of Materials Science & Technology 2022年第1期96卷 295-307页

作者： Luqing Cui Cheng-Han Yu Shuang Jiang Xiaoyu Sun Ru Lin Peng Jan-Erik Lundgren Johan Moverare Division of Engineering Materials Department of Management and EngineeringLinköping UniversityLinköping SE-58183Sweden Siemens Energy ab Finspång SE-61231Sweden

Dislocation plays a crucial role in controlling the strength and plasticity of bulk ***,determining the densities of geometrically necessary dislocations(GNDs)and statistically stored dislocations(SSDs)is one of the classical problems in material research for several ***,we proposed a new approach based on indentation size effect(ISE)and strengthening *** approach was performed on a laser powder bed fused(L-PBF)Hastelloy X(HX),and the results were verified by the Hough-based EBSD and modified Williamson-Hall(m-WH)***,to better understand the new approach and essential mechanisms,an in-depth investigation of the microstructure was *** distribution of dislocations shows a clear grain orientation-dependent:low density in largepreferentially orientated grains while high density in fineorientated *** increment of strengthening in L-PBF HX is attributed to a huge amount of *** slip is the main operative deformation mechanism during indentation tests,and the slip step patterns depend mostly on grain orientations and stacking fault *** study provides quantitative results of GND and SSD density for L-PBF HX,which constructs a firm basis for future quantitative work on other metals with different crystal structures.

关键词： Microstructure characterization Indentation size effect Hastelloy X Geometrically necessary dislocation Statistically stored dislocation

Seismic evaluation of the destress blasting efficiency

在线全文

学校读者我要写书评

暂无评论

Journal of Rock Mechanics and Geotechnical Engineering 2022年第5期14卷 1501-1513页

作者： Krzysztof Fuławka Piotr Mertuszka Witold Pytel Marcin Szumny Tristan Jones Research and Development Centre KGHM Cuprum Ltd.Wrocław53-659Poland Luossavaara-Kiirunavaara ab(LKab) MalmbergetSE-98381Sweden

In this paper, selected methods of destress blasting efficiency assessment are presented, and novel quantitative methods based on in situ seismic measurements are proposed. The newly formulated solution combines two different approaches. The first, which is useful mostly for the near-field seismic analyses, is based on the analysis of seismic amplitude characteristics, and the second, relevant for farfield evaluation, is extended by the duration and frequency of the seismic wave. Both approaches are based on the seismic analyses of the waveforms generated by blasting recorded by the local seismic network. The proposed solutions are tested and validated in deep underground mines in Poland in which the room-and-pillar mining method is applied. Based on performed analysis, it is shown that both methods may be used as a rockburst hazard control in underground mines. However, developed methods may also be successfully implemented in other engineering practices, including the assessment of seismic vibrations in open pits and quarries.

关键词： Rockburst hazard Destress blasting Induced seismicity Seismic events Dominant frequency

Iterative photonic processor for fast complexvalued matrix inversion

在线全文

学校读者我要写书评

暂无评论

Photonics Research 2022年第11期10卷 2488-2501页

作者： MINJIA CHEN QIXIANG CHENG MASAFUMI AYATA MARK HOLM RICHARD PENTY Department of Engineering Centre for Photonic SystemsElectrical Engineering DivisionUniversity of CambridgeCambridge CB30FAUK Huawei Technologies(Sweden)ab 16440 KistaSweden

An N×N iterative photonic processor is proposed for the first time, we believe, for fast computation of complexvalued matrix inversion, a fundamental but computationally expensive linear algebra operation. Compared to traditional digital electronic processing, optical signal processing has a few unparalleled features that could enable higher representational efficiency and faster computing speed. The proposed processor is based on photonic integration platforms–the inclusion of Ⅲ-V gain blocks offers net neutral loss in the phase-sensitive loops. This is essential for the Richardson iteration method that is adopted in this paper for complex linear systems. Wavelength multiplexing can be used to significantly improve the processing efficiency, allowing the computation of multiple columns of the inverse matrix using a single processor core. Performances of the key building blocks are modeled and simulated, followed by a system-level analysis, which serves as a guideline for designing an N×N Richardson iteration processor. An inversion accuracy of>98%can be predicted for a 64×64 photonic processor with a>80times faster inversion rate than electronic processors. Including the power consumed by both active components and electronic circuits, the power efficiency of the proposed processor is estimated to be over an order of magnitude more energy-efficient than electronic processors. The proposed iterative photonic integrated processor provides a promising solution for future optical signal processing systems.

关键词： valued matrix iteration