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Utilizing dimensional Analysis with Observed data to determine the Significance of Hydrodynamic Solutions in Coastal Hydrology

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Computational Water, Energy, and Environmental Engineering 2014年第2期3卷 57-77页

作者： Eric d. Swain Jeremy d. decker Joseph d. Hughes US Geological Survey Florida Water Science Center Fort Lauderdale USA US Geological Survey Florida Water Science Center Tampa USA

In this paper, the authors present an analysis of the magnitude of the temporal and spatial acceleration (inertial) terms in the surface-water flow equations and determine the conditions under which these inertial terms have sufficient magnitude to be required in the computations. data from two South Florida field sites are examined and the relative magnitudes of temporal acceleration, spatial acceleration, and the gravity and friction terms are compared. Parameters are derived by using dimensionless numbers and applied to quantify the significance of the hydrodynamic effects. The time series of the ratio of the inertial and gravity terms from field sites are presented and compared with both a simplified indicator parameter and a more complex parameter called the Hydrodynamic Significance Number (HSN). Two test-case models were developed by using the SWIFT2d hydrodynamic simulator to examine flow behavior with and without the inertial terms and compute the HSN. The first model represented one of the previously-mentioned field sites during gate operations of a structure-managed coastal canal. The second model was a synthetic test case illustrating the drainage of water down a sloped surface from an initial stage while under constant flow. The analyses indicate that the times of substantial hydrodynamic effects are sporadic but significant. The simplified indicator parameter correlates much better with the hydrodynamic effect magnitude for a constant width channel such as Miami Canal than at the non-uniform North River. Higher HSN values indicate flow situations where the inertial terms are large and need to be taken into account.

关键词： Hydrodynamic dimensional Analysis Coastal Numerical Modeling

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Structural and corrosion characterization of biodegradable Mg-RE (RE=Gd, Y, Nd) alloys

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Transactions of Nonferrous Metals Society of China 2013年第5期23卷 1215-1225页

作者： J.KUBSEK d.VOJTěCH department of Metals and Corrosion Engineering Institute of Chemical Technology

Binary Mg-Gd （up to 5% Gd in mass fraction）, Mg-Nd （up to 9% Nd in mass fraction） and ternary Mg-Gd-Y （up to 5% Gd, 1% Y） alloys with precisely determined contents of cathodic impurities （Fe, Ni, Cu, Co） were studied. The alloys were studied in the as-cast state （cooling rate of 500 K/min） and after solution heat treatment （T4）. Structures were investigated by optical and scanning electron microscopy, energy dispersive spectrometry, X-ray diffraction and glow discharge spectrometry. Structural investigation was completed by Vickers hardness measurements. Corrosion behavior in the simulated physiological solution （9 g/L NaCl） was assessed by immersion tests and potentiodynamic measurements. It was found that the structures of the as-cast alloys were dominated by fine a-Mg dendrites and eutectic Mg-RE phases. The dendrites exhibited RE-concentration gradients which were most pronounced in the Mg-Gd alloys. For this reason, the T4 heat treatment of the Mg-Gd alloy led to the formation of a new cuboidal Mg5Gd phase. The corrosion resistance was significantly improved by Gd. The effect of Nd was weak and the addition of Y to Mg-Gd alloys had harmful effect on the corrosion resistance. The T4 heat treatment strongly accelerated the corrosion of Mg-Gd alloys. Its effect on the corrosion of Mg-Nd alloys was not significant. The observed corrosion behavior of the alloys was discussed in relation to their structural states and contents of cathodic impurities.

关键词： biodegradable material magnesium rare earths Mg-RE alloy structure corrosion

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One and Two Photon Excitation of Radiofrequency Trapped Ca

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Chinese Journal of Chemical Physics 2009年第2期22卷 119-122页

作者： C. Zumsteg C. Champenois d. Guyomarc'h G. Hagel M. Houssin M. Knoop Physique des Interactions Ioniques et Moléculaires (CNRS UMR 6633) Université de Provence Centre de Saint Jérome Case C21 13397 Marseille Cedex 20 France

Radiofrequency （rf） trapped ions are versatile candidates for a large panel of applications ranging from quantum information to the creation of cold molecules. Sample size can range from a single to 10^6 ions, and the internal and external energy states of the atoms can be controlled with high precision. In the experiment, we focus on different protocols related to frequency metrology using rf trapped Ca.

关键词： Radiofrequency trapped ion Frequency metrology Laser stabilisation

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Molecular dynamics Simulation of Porous Layer-enhanced dislocation Emission and Crack Propagation in Iron Crystal

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Journal of Materials Science & Technology 2011年第11期27卷 1025-1028页

作者： d. Li F.Y. Meng X.Q. Ma L.J. Qiao W.Y. Chu department of Physics University of Science and Technology Beijing Beijing 100083 China Corrosion and Protection Center Key Lab of Environmental Fracture （Ministry of Education） University of Science and Technology Beijing Beijing 100083 China

The internal stress induced by a porous layer or passive layer can assist the applied stress to promote dislocation emission and crack propagation, e.9. when the pipeline steel is buried in the soil containing water, resulting in stress corrosion cracking （SCC）. Molecular dynamics （Md） simulation is performed to study the process of dislocation emission and crack propagation in a slab of Fe crystal with and without a porous layer on the surface of the crack. The results show that when there is a porous layer on the surface of the crack, the tensile stress induced by the porous layer can superimpose on the external applied stress and then assist the applied stress to initiate crack tip dislocation emission under lowered stress intensity KI, or stress. To respond to the corrosion accelerated dislocation emission and motion, the crack begins to propagate under lowered stress intensity KI, resulting in SCC.

关键词： Molecular dynamics simulation dislocation emission Crack propagation Porouslayer Stress intensity

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A solution to unit commitment problem using invasive weed optimization algorithm

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Frontiers in Energy 2013年第4期7卷 487-494页

作者： B. SARAVANAN E. R. VASUdEVAN d. P. KOTHARI School of Electrical Engineering Vellore Institute of Technology University Vellore 632014 India JB Group of Educational Institutions Hyderabad 500 034 India

Unit commitment （UC） is one of the most important aspect of power generation in the world today. Though, there is no method to find the exact optimized solution, there exists several meta-heuristic algorithms to determine the close to exact solution. This paper proposes a novel solution to effectively determine UC and generation cost using the technique of invasive weed optimization （IWO）. The existing technique distributes the load demand among all the generating units. The method proposed here utilizes the output of UC obtained by using the Lagrangian relaxation （LR） method and calculates the required generation from only the plants that are ON discarding the OFF generator units and thereby giving a faster and more accurate response. Moreover, the results show the comparison between the LR-particle swarm optimization （PSO） and LR-IWO, and prove that the cost of generation for a 4 unit, 8 hour schedule is much less in the case of IWO when compared to PSO.

关键词： Lagrangian relaxation (LR) invasive weed optimization (IWO) economic dispatch optimization fuel cost seed fitness

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Spatial variation and prediction of forest biomass in a heterogeneous landscape

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Journal of Forestry Research 2012年第1期23卷 13-22页

作者： S. Lamsal d. M. Rizzo R. K. Meentemeyer department of Geography and Earth Sciences University of North Carolina Charlotte NC U. S. A department of Plant Pathology University of California Davis CA U. S. A.

Large areas assessments of forest bioinass distribution are a challenge in heterogeneous landscapes, where variations in tree growth and species composition occur over short distances. In this study, we use statistical and geospatial modeling on densely sample.d forest biomass data to analyze the relative importance of ecological and physiographic variables as determinants of spatial variation of forest biomass in the environmentally heterogeneous region of the Big Sur, California. We estimated biomass in 280 forest Plots （one plot per 2.85 km2） and meas- ured an array of ecological （vegetation community type, distance to edge, amount of surrounding non-forest vegetation, soil properties, fire history） and physiographic drivers （elevation, potential soil moisture and solar radiation, proximity to the coast） of tree growth at each plot location. Our geostatistical analyses revealed that biomass distribution is spatially structured and autocorrelated up to 3.1 kin. Regression tree （RT） models showed that both physiographic and ecological factors influenced bio- mass distribution. Across randomly selected sample densities （sample size 112 to 280）, ecological effects of vegetation community type and distance to forest edge, and physiographic effects of elevation, potential soil moisture and solar radiation were the most consistent predictors of biomass. Topographic moisture index and potential solar radiation had apositive effect on biomass, indicating the importance of topographically- mediated energy and moisture on plant growth and biomass accumula- tion. RT model explained 35% of the variation in biomass and spatially autocorrelated variation were retained in regession residuals. Regression kriging model, developed from RT combined with kriging of regression residuals, was used to map biomass across the Big Sur. This study dem- onstrates how statistical and geospatial modeling can be used to dis- criminate the relative importance of physiographic and ecologic effect

关键词： forest biomass landscape heterogeneity spatial variation semivariogram regression tree regression kriging Big Sur California

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Experimental Study on the Uniaxial Cyclic deformation of 25CdV4.11 Steel

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Journal of Materials Science & Technology 2005年第1期21卷 5-9页

作者： Guozheng KANG, Qianhua KAN and Juan ZHANGdepartment of Applied Mechanics and Engineering, Southwest Jiaotong University, Chengdu 610031, ChinaProf., Ph.d., dept. of Appl. Mech. and Eng. Southwest Jiaotong Univ. Chengdu 610031 China

The strain cyclic characteristics and ratcheting behavior of 25CdV4.11 steel were studied by the experiments under uniaxial cyclic loading with relatively high cyclic number and at room temperature. The cyclic hardening/softening feature of the material was first observed under the uniaxial strain cycling with various strain amplitudes. Then, the ratcheting behavior of the material was researched in detail, and the effects of stress amplitude and mean stress on the ratcheting were discussed under uniaxial asymmetrical stress cycling. Comparing with the experimental results of SS316L stainless steel, it is concluded that the material exhibits remarkable cyclic softening feature, and then a special ratcheting behavior is caused. Some conclusions useful to establish corresponding constitutive model are obtained.

关键词： Ratcheting Cyclic softening Cyclic plasticity Uniaxial loading

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Laser cladded AlCuFe+Sn quasicrystalline composite coatings

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中国有色金属学会会刊：英文版 2005年第2期15卷 432-436页

作者：冯莉萍邵天敏金永吉 E.Fleury d.H.Kim 陈大融魏悦广 State Key Laboratory of Tribology Tsinghua University Beijing 100084 China State Key Laboratory of Non-Linearity Mechanics Insititute of Mechanics Chinese Academy of Sciences Beijing 100080 China Korea Institute of Science and Technology Seoul 130-650 Korea Center for Noncrystalline Materials Yonsei University Seoul 120-749 Korea

Al-Cu-Fe+Sn quasicrystalline(QC) composite coatings with different volume fractions of Sn, i.e.(12%,) (20%) (and 30%,) were prepared by laser cladding technique. The effects of soft phase Sn and processing parameters on the microstructure, microhardness and frictional behavior of the coatings were investigated. The results show that after laser cladding, i-phase existing in the powder is decomposed and element Sn reacts with Cu, forming β-CuSn. The volume fraction of Sn addition has less obvious effect on the microstructure, microhardness and friction performance than that of plasma sprayed coatings. The best performance in terms of microhardness and friction are (obtained) for the coating containing 20% Sn additions prepared with the laser power of 950 W and scanning velocity of 3 mm/s.

关键词：激光覆层电镀工艺铝铜铁锡复合材料摩擦性质

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Influence of free fatty acid content and degree of fat saturation on production performance,nutrient digestibility,and intestinal morphology of laying hens

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Animal Nutrition 2023年第2期13卷 313-323页

作者： María Palomar Carlos Garces-Narro Olga Piquer Roser Sala Alba Tres Jose AGarcía-Bautista María d.Soler AviFeed Science Department of Animal Production and HealthFacultad de VeterinariaUniversidad CEU Cardenal Herrera e CEU UniversitiesE-46115Alfara de PatriarcaValenciaSpain Animal Nutrition and Welfare Service Department of Animal and Food ScienceFacultat de VeterinariaUniversitat Autonoma de BarcelonaE-08193BellaterraBarcelonaSpain departament de Nutrici Ciencies de l’Alimentaci i GastronomiaFacultat de Farmacia i Ciencies de l’AlimentaciUniversitat de BarcelonaE-08921Santa Coloma de GramenetBarcelonaSpain

This study was conducted to evaluate the effects of dietary free fatty acid(FFA)content and degree of fat saturation on production performance,lipid and calcium digestibility,and intestinal function of laying *** a 15-week period,a total of 144 laying hens(19 weeks old)were randomly assigned to 8 dietary treatments,which were obtained by gradually replacing crude soybean oil with soybean acid oil(AO),or crude palm oil with palm fatty acid distillate(FAd).Thus,there were 4 soybean and 4 palm diets with 6%added fat varying in their FFA percentage(10%,20%,30%,and 45%),following a 2×4 factorial *** treatment included 6 replicates with 3 birds per *** daily feed intake and final body weight were significantly higher in palm diets(Pdifferences were found in egg mass and feed conversion *** levels of FFA in soybean diets resulted in lower egg production and higher egg weight(linear,Pding the degree of fat saturation,hens fed soybean diets presented higher digestibility of ether extract(EE),fatty acids,and calcium than palm diets(Pdietary FFA percentage negatively affected the digestibility of EE and calcium(Pd in soybean diets as the dietary FFA percentage increased(linear,Pdiets remained *** experimental diets had little effect on gastrointestinal weight and ***,the jejunum of soybean diets showed higher villus height and higher villus height-to-crypt depth ratio than palm diets(Pd the dietary FFA percentage increased the crypt depth and decreased the villus height-to-crypt depth ratio(linear,Pded that varying dietary FFA content did not affect fat utilization as much as the degree of saturation did,supporting the use of AO and FAd as alternative fat ingredients.

关键词： Acid oil Fat by-product Fatty acid distillate Lipid Calcium

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Performance evaluation of operational energy use in refurbishment, reuse, and conservation of heritage buildings for optimum sustainability

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Frontiers of Architectural Research 2016年第3期5卷 371-382页

作者： O.K. Akande d. Odeleye, A. Coday C.Jimenez Bescos department of Engineering & the Built Environment Anglia Ruskin University Chelmsford United Kingdom

The operational phase of a building project has increasingly gained importance with their energy performance becoming valuable and determining their operational excellence. In most heritage building projects （HBPs）, the operational energy use aspects are less considered, and a systematic way of analyzing their energy performance following project delivery is often lacking, The aim of this study is to evaluate the operational performance of refurbishment and reuse of UK listed church projects. The objective is to assess the operational energy use with a view to optimizing their sustafnabie performance. The methodology includes eight selected case study buildings refurbished and converted for multipurpose use. The case study approach provided qualitative insights into how the study contributes to a more structured requirements for energy management in HBPs with specific attention to energy-efficient building operations. The findings show the need to focus on fundamental areas of operational management （i.e. by developing and implementing more focused policy on operational energy performance of heritage buildings） to minimize the energy required to operate them. The challenges of implementing changes in operational energy performance improvement of heritage buildings are addressed in the form of recommendations that could Lead to real results. The study concludes that leveraging these areas requires commitment from all heritage building stakeholders because they all have substantial roles in harmonizing the requirement for the project＇s sustainability and not just the building operators. Meanwhile, baseline project planning, periodic updating, monitoring, and managing the energy use pattern are suggested as measures that could greatly facilitate better energy performance to optimizing their sustainable reuse compared with the traditional approach of trying to improve their thermal performance.

关键词： Heritage buildings Listed churches Operational energy Performance Refurbishment Sustainabitity

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