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A Hybrid Immersed Interface Method for driven Stokes Flow in an Elastic Tube

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Numerical Mathematics(Theory,Methods and Applications) 2013年第4期6卷 600-616页

作者： Yi Li Sarah A.williams Anita T.Layton department of Mathematics Duke UniversityDurhamNC 27708-0320USA

We present a hybrid numerical method for simulating fluid flow through a compliant,closed tube,driven by an internal source and *** is assumed to be highly viscous with its motion described by Stokes *** geometry is assumed to be axisymmetric,and the governing equations are implemented in axisymmetric cylindrical coordinates,which capture 3d flow dynamics with only 2d *** solve the model equations using a hybrid approach:we decompose the pressure and velocity fields into parts due to the surface forcings and due to the source and sink,with each part handled separately by means of an appropriate *** the singularly-supported surface forcings yield an unsmooth solution,that part of the solution is computed using the immersed interface *** conditions are derived for the axisymmetric cylindrical *** velocity due to the source and sink is calculated along the tubular surface using boundary *** results are presented that indicate second-order accuracy of the method.

关键词： Stokes flow interface tracking immersed interface methods axisymmetric cylindrical coordinates boundary integrals

FREEZE/THAW EFFECTS ON RILL ANd GULLY EROSION IN THE NORTHWESTERN WHEAT ANd RANGE REGION

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International Journal of Sediment Research 2005年第3期20卷 48-56页

作者： d. K. MCCOOL,J. d. williams Supervisory Agricultural Engineer Land Management and Water Conservation Research USdA-ARS Pullman WA USA Hydrologist Columbia Plateau Conservation Research Center USdA-ARS Pendleton OR.

Hydrology of the Northwestern Wheat and Range Region (NWRR) of the Pacific Northwest USA is dominated by winter events. Fifty-five to sixty-five percent of the precipitation occurs from November through March, and formation of impermeable frost, intensified by excessive tillage and tillage pans, has long been a major factor in rill and gully formation in the region. Saturated zones can form above tillage pans, freeze solid, and significantly reduce infiltration. Frost heaved surface soils thaw and weaken with warming temperatures or rain. Under these conditions, runoff from rain or snowmelt or a combination of the two is inevitable, concentrating in rills and channels, and carrying with it the loosened soil. Slopes are frequently quite steep and there may be little deposition above the toe slope. Classical over-fall head-cut gullies are uncommon. Concentrated flow channels form because of collection of water from impervious areas such as conventionally tilled fall seeded small grains and bare grass seed fields. In some soils, gullies are created by seepage from saturated layers above permanent restrictive layers in the soil. Gullies can also result from terrace failures due to rodent burrows and low compaction at the time of construction. In naturally unconsolidated soil, rodent activity can lead to piping failures that remove large quantities of subsurface soil and can become gullies. Rill measurements on conventionally tilled fields in Oregon, Washington, and Idaho were used to determine coefficients for relationships between slope length and steepness and size of rills. This paper describes these studies and the results as well as analysis of long-term erosion and weather records from southeastern Washington.

关键词： Erosion Slope length Slope steepness Topography Pacific Northwest Frozen soil Thawing soil

Assessment of the Factor Influencing the Corporate Culture of Employees Satisfaction on the Example of "The Ritz-Carlton Beijing" Hotel

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Assessment of the Factor Influencing the Corporate Culture o...

作者： Kavul Sabu williams 浙江工商大学

学位级别：硕士

研究课题的相关性取决于企业文化的概念是全面的,需要在任何组织中密切关注。在酒店业务中创建和实施企业文化需要管理层的密切关注,因为通过它公司有机会影响其员工的活动。评估企业文化有效性的过程非常有趣,因为并非每种文化在单独... 详细信息

研究课题的相关性取决于企业文化的概念是全面的,需要在任何组织中密切关注。在酒店业务中创建和实施企业文化需要管理层的密切关注,因为通过它公司有机会影响其员工的活动。评估企业文化有效性的过程非常有趣,因为并非每种文化在单独的组织中都可行,而且并非所有员工都愿意接受并遵循这些价值观。不幸的是,与酒店和餐厅业务相关的现代问题是员工的情绪疲惫和倦怠,这与他们的专业活动和与大量人员一起工作的需要有关。论文的目的是以酒店综合体“北京丽思卡尔顿酒店”为例,识别影响企业文化有效性的因素,确定企业文化与员工情绪耗竭之间的联系。为了评估企业文化,建议使用修改后的模型OCAI（修改）-组织文化评估工具（Macey＆Fink,2020,第144页）。为了评估当前的企业文化质量,使用了OCAI（组织文化评估工具）模型。该模型的目的是根据各种标准评估员工满意度:（1）企业最重要的特征;（2）企业领导的总体风格;（3）员工管理所依据的原则;（4）凝聚员工的价值观和理念;（5）战略目标和成功标准;（6）员工在其专业职责过程中的自我评估;（7）存在过度劳累和职业倦怠迹象。本研究采用问卷调查法;问卷结果采用SPSS统计分析。根据研究结果,得出以下结论:（1）调研结果表明,在调研过程中,北京丽思卡尔顿酒店拥有完善的企业文化和企业社会责任体系。特别是,员工对酒店企业文化的几乎所有组成部分都给予了积极的反馈。酒店员工对薪酬奖金制度、职业培训制度和企业社会责任表示赞赏。正如第一个假设所示,北京丽思卡尔顿酒店的员工将他们在酒店工作的愿望与酒店向正式员工提供的大量偏好和奖金联系起来。研究结果让我们证实了研究的第一个假设:如果工资水平、奖金、社会保障水平、晋升机会和职业培训质量往往较高,那么工作愿望往往表现出较高水平。（2）同时,调查结果可以断言,北京丽思卡尔顿酒店的员工希望达到职业和事业的高度,经常过度工作,这对他们的健康产生负面影响。许多员工抱怨头痛、高度疲劳、高血压或低血压。（3）北京丽思卡尔顿酒店员工对社会保障体系、工资水平和社会福利感到满意;然而,为了在职业阶梯上更上一层楼,他们必须以几乎不间断的速度不断学习和努力。北京丽思卡尔顿酒店的许多员工没有时间正常休息和恢复,下班后他们会非常疲倦,其中许多人都出现了健康问题。基本上,接触区域的员工在更大程度上遇到健康问题,在酒店餐厅工作,在酒店水疗中心工作,是女佣,因为他们必须不断与大量的人交流。酒店经理也因为必须密切关注酒店运营而精神疲惫。虽然北京丽思卡尔顿酒店的企业管理为员工提供了多种社交选择,但北京丽思卡尔顿酒店的最高价值是酒店客人,而不是员工。酒店员工被迫努力工作并不断接受持续的专业培训,这会造成很大的压力并影响健康。为解决职业疲劳问题,提出为每位员工制定职业生涯规划,在职业发展和个人生活之间取得平衡,最大限度地降低情绪疲劳水平。

关键词：企业文化酒店业务情绪耗竭职业规划

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温差电材料热导率的激光脉冲测试法

红外技术 1993年第6期15卷 9-14页

作者：高敏 S.G.K.williams d.M.Rowe 昆明物理研究所昆明650223 英国威尔士大学

简要地介绍了热导率激光脉冲法的测量原理和实际装置,着重对该方法在半导体温差电材料热导率测试中的问题和解决途径进行了详细的讨论。

关键词：热导率测量温差材料激光脉冲

β-Octafluorinated tetrakis(ethoxycarbonyl)porphyrin

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Chinese Chemical Letters 2015年第5期26卷 529-533页

作者： Hua-Hua Wang Yi-Yu Jiang Mian HR Mahmood Hai-Yang Liu Herman H.Y.Sung Ian d.williams Chi K.Chang department of Chemistry South China University of Technology department of Chemistry Hong Kong University of Science and Technology department of Chemistry Michigan State University

Tetrakis（alkoxycarbonyl）porphyrin and its β-octafluoro-substituted derivatives were synthesized via Lindsey method and transformed to their zinc complexes. Single crystal X-ray structures of corresponding Zn（II） porphyrins revealed that β-octafluorination will give more compactness of porphyrin moieties in the crystal structure owing to the hydrogen bonding interactions involving β- fluorine atoms. An unusual six-coordinated Zn（II） was found via intramolecular coordination of oxygen atom of meso-substituents with central Zn（II）.

关键词： Tetraalkyl porphyrin Zinc Ethyl glyoxylate 3 4-difluoropyrrole

diel and seasonal patterns of variation in the singing behaviour of Savannah Sparrows (Passerculus sandwichensis)

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Avian Research 2019年第3期10卷 336-343页

作者： Ines G.Moran Katrina C.Lukianchuk Stephanie.M.doucet Amy E.M.Newman Heather williams d.Ryan Norris daniel J.Mennill department of Biological Sciences University of WindsorWindsorON N9B3P4Canada department of Integrative Biology University of GuelphGuelphON N1G2W1Canada Biology department Williams CollegeWilliamstownMD 01267USA

Background:The vocalizations of birds are dynamic traits that often vary in output with time of day and time of *** quantifying patterns of diel and seasonal variation in vocal output,we can gain insight into the ecology and evolution of birds and the function of their *** this investigation,we quantified diel and seasonal variation in song output by studying a breeding population of Savannah Sparrows (Passerculus sandwichensis).Methods:We used autonomous recorders to collect extensive recordings across the breeding season in a long-term, colour-marked study population of Savannah Sparrows in eastern *** described diel and seasonal variation across five different breeding stages based on recordings of more than 50,000 songs from 34 ***:during the pre-breeding stage, prior to female arrival, males sang a pronounced dawn chorus with a peak in song output during the early *** the breeding stage,in contrast,the dawn chorus was diminished and males instead exhibited a pronounced dusk chorus with a peak in song output during the *** the breeding season,the highest levels of song output occurred in late April and early May,soon after males arrived on the breeding grounds,and the lowest levels occurred in August,prior to the departure of birds for the wintering ***:These patterns suggest that Savannah Sparrows' early-season dawn choruses are directed at males and serve a territorial defense ***-season dusk choruses,in contrast, appear to play a role in attracting mates and possibly acoustic mate guarding.

关键词： Bird song Breeding activities Circadian rhythms Seasonal variation in song

Quiet in the nest:The nest environment attenuates song in a grassland songbird

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Avian Research 2023年第4期14卷 623-629页

作者： Sarah L.dobney Mikayla M.K.Bornais d.Ryan Norris Amy E.M.Newman Heather williams Stéphanie M.doucet daniel J.Mennill department of Integrative Biology University of WindsorWindsorOntarioN9B 3P4Canada department of Integrative Biology University of GuelphGuelphOntarioN1G 2W1Canada Biology department Williams CollegeWilliamstownMA01267USA

The nest environment may limit the ability of nest-bound birds to hear sounds from the outside *** vocal learning species,such as humans and songbirds,it is vital for young animals to hear the voices of conspecific animals early in *** songbirds,nest structure varies considerably across species,and the resulting impact on sound transmission may have consequences for vocal learning in *** this study,we tested the hypothesis that the nest environment attenuates song of Savannah Sparrows(Passerculus sandwichensis),grassland songbirds that build nests on the ground under cover of dense *** recorded live Savannah Sparrows singing at variable distances from 21 *** recorded songs using one microphone inside the nest(the typical position of a nestling)and another placed 1 m directly above the nest(a typical position of an adult).We found a substantial reduction in signal-to-noise ratio,where songs recorded inside the nest were an average of 11 dB lower than songs recorded directly above the *** estimate that the attenuation imposed by the nest reduced the maximum acoustic environment from 117.7 m(for recordings above the nest),to 78.6 m(for recordings within the nest),which is analogous to listening from a position 39.1 m farther away from the *** research estimated that song transmits up to 100 m in this species,so any adult male within 100 m of a young bird was previously considered a potential vocal *** reducing the nestling acoustic environment from 100 m to 78.6 m,the number of male tutors available to nestlings is reduced by an average of 27%.Given the growing evidence that song learning begins very early in life,future research on vocal development should account for how the structural properties of the natal environment affect the songs that nestlings hear.

关键词： Acoustic environment Nest environment Songbird Sound attenuation Vocal learning

Water flow simulation and analysis in HMA microstructure

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Journal of Traffic and Transportation Engineering(English Edition) 2014年第5期1卷 362-370页

作者： Can Chen R.Christopher williams Graniterock Construction Company department of Civil Constructionand Environmental EngineeringIowa State University

This paper introduces a new method for reconstructing virtual two-dimensional （2-d） micro- structure of hot mix asphalt （HMA）. Based on the method, the gradation of coarse aggregates and the film thickness of the asphalt binder can be defined by the user. The HMA microstructure then serves as the input to the computational fluid dynamic （CFd） software （ANSYS-FLUENT） to investigate the water flow pattern through it. It is found that the realistic flow fields can be simulated in the 2-d micro- structure and the flow patterns in some typical air void structures can be identified. These flow patterns can be used to explain the mechanism that could result in moisture damage in HMA pavement. The one-dimensional numerical permeability values are also derived from the flow fields of the 2-d HMA microstructure and compared with the measured values obtained by the Karol-Warner permeameter. Be- cause the interconnected air voids channels in actual HMA samples cannot be fully represented in a 2-d model, some poor agreements need to be improved.

关键词： hot mix asphalt microstructure simulation water flow

Evaluation of fall armyworm resistance in maize germplasm lines using visual leaf injury rating and predator survey

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Insect Science 2014年第5期21卷 541-555页

作者： Xinzhi Ni Wenwei Xu Michael H. Blanco W. Paul williams USdA-ARS Crop Genetics and Breeding Research Unit University of Georgia-Tifton Tifton GA 31793 Agricultural Research &Extension Center Texas A&M University Lubbock TX 79403 USdA-ARS Plant Introduction Research Unit Iowa State UniversityAmes IA 50011 Corn Host Plant Resistance Research Unit USDA-ARS Mississippi State MS 39762 USA

After examining ear-colonizing pest resistance, 20 maize lines from the USdA- ARS Germplasm Enhancement of Maize （GEM） Program were evaluated for whorl-feeding fall armyworm （FAW）（Spodopterafrugiperda） resistance using 4 maize inbred lines as the resistant and susceptible controls. Both FAW injury ratings at 7- and 14-d after infestation, and predator abundance and diversity at whorl stage （V6-V8） were recorded in 2009 and 2010. The survey of the diversity and abundance of predators in each experimental plot were conducted 7 d after the FAW infestation. Of the 20 germplasm lines examined, 3 of them （i.e., entries 9, 15, and 19 that were derived from tropical maize germplasm lines were originated from Uruguay, Cuba, and Thailand, respectively） were identified as the best FAW-resistant germplasm lines using the leaf injury ratings and predator survey data. In addition, the abundance and diversity of the predators were greater in 2010 than in 2009, which might have caused the low level of the FAW injury ratings on all lines examined in 2010. The 2-year data showed that the FAW injury ratings were negatively correlated to the predator abundance and diversity, which is also influence by genotype × environment interactions. The findings suggested that tropical germplasm is an important source of native resistance to the FAW and the corn earworm. At the same time, the maize genotype x environment interaction （e.g., predator attractiveness, and varying weather conditions） should be included in the multiple-year evaluations of insect and disease resistance of maize germplasm lines under field conditions.

关键词： field screening genotype × environment interactions multiple insect resistance predator abundance and diversity whorl-feeding