bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal Transportation Solution to International Project Logistics Based on Decision Network Planning
Authors: Yang Hua Long , Ji Ying Feng , Cao Hui , Wang Liang Liang
Published: August 2011

To succeed in uncertain and constantly changing international business environment, firms need to adopt international project logistics. This paper explores the characteristics and analyzes the current situation related to the concept of international project logistics. The optimization model for transportation solution to international project logistics was established based on decision network planning technique and uncertainty theory. Stochastic programming theory was also applied to solve the model which allows decision-makers to reduce the total cost to as low as possible, guaranteed by a certain probability. Finally, an empirical study on international project logistics was conducted to verify the validity of the model. The knowledge gained from findings of this research can be used as framework for the development of international project logistics.
Research on Manufacturing Supply Chain Information Platform Architecture Based on Internet of Things
Authors: Sun Zheng Wu , Li Wen Feng , Song Wei , Jiang Peng
Published: August 2011

The means of gathering information of manufacturing supply chain information sharing platform at the present stage are traditional and affect the speed of real-time sharing of information. Therefore, with the new rising technology of Internet of Things (IOT), this thesis establishes information real-time sharing platform architecture of manufacturing industry supply chain based on IOT in order to improve the efficiency of information collection and sharing. This thesis also provides a new solution for the information transparency construction of the supply chain.
Extracting the Rules of KPIs for Equipment Management Based on Rough Set Theory
Authors: Wang Jia Wen , Cheng Ching Hsue
Published: August 2011

This paper practically collects manufacturing supplier dataset in Taiwan. The dataset includes production records, and there are 18 attributes such as production scheduling, scheduled downtime, process, etc. For comparison, decision tree, naive bayesian, and multi-layer perceiving are utilized to compare with the proposed procedure in classification accuracy. The results show that the correct rate of rough set theory is not only superior to decision trees, naive bayesian, and multi-layer perceiving (MLP), and the proposed procedure can be easy to understand and produce fewer rules. In managerial implication, the results can generate predictive model, and classifiable rule which can help manufacturing to find out key related factors in equipment throughput and use the rules generated as a capacity planning assessment.
Jet Performance Testing of High-Pressure Waterjet Descaling Nozzles
Authors: Ma Fei , Li Yong , Song Zhi Ming
Published: August 2011

Descaling nozzles, generator of high-speed waterjets, are key components in high-pressure waterjet descaling system. Jet performance of the nozzle has great effect on hot-rolling steel billet descaling. Most domestic manufactures provide nozzle structural data and impact force scale with rated pressure, such as orifice diameter, injecting angle and scattering angle. However, jet distribution shape and jet impact force distribution and strength, which are major parameters affecting steel billet descaling quality, are not available from manufactures. A jet performance test device for nozzles was developed in this paper. Two and three dimensional graphs of jet impact force distribution with different standoff distance were obtained. Shape of jet distribution area was indicated in two dimensional graphs while jet impact strength and distribution were given in three dimensional graphs, providing evidence for jet performance judgement. Injecting angle, scattering angle and flow volume coefficient could also be measured with the device. A fan-type nozzle used for scale removal was tested. Results obtained were presented and discussed.
Effect of Atomic Oxygen Exposure on Si Implanted Siloxane Coatings in Low Earth Orbit Environment
Authors: Duo Shu Wang , Song Mi Mi , Liu Ting Zhi , Li Mei Shuan
Published: August 2011

To improve the AO erosion resistance of siloxane coating, the Si ion implantation with nominal dosage of 7×1016 ions/cm2 in siloxane coatings on the polyimide substrate was carried out by using the plasma immersion ion implanter. The Si implanted siloxane coatings before and after AO exposure in the ground-based AO simulation facility were investigated by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS). The results of mass measurement shown that, in initial stage of AO exposure the implanted sample had a small mass change, and then was stabilized. The erosion yield of the implanted siloxane coating decreased by a factor of more than two orders of magnitude compared with that of the polyimide film, and decreased by a factor of more than an order of magnitude than that of unimplanted siloxane coatings. The results through SEM and XPS indicated that a continuous high-quality protective SiO2 surface layer was formed on the implanted siloxane coatings after the AO exposure. It can prevent further degradation of the underlying polymer with increased exposure to the AO flux and provide high-quality erosion protection for these materials. The Si implanted materials have a markedly increased erosion resistance than unimplanted siloxane coatings in AO environment.
Study on Cutting Force and Cutting Temperature of Coated Carbide Turning Inserts with 3D Chip-Breaker
Authors: He Yun , Xiao Min , Ni Hao , Bian Yi Chuan , Wang Min
Published: August 2011

In this paper, four types P turning insert groove with 3D chip-breaker are investigated for the influence of cutting force, cutting temperature and chip deformation. The experimental result shows that cutting force and total cutting heat corresponding different insert type are not the same between each other. These experiments also show that the arrangement sequence of chips deformation is consistent with that of cutting temperature for four kind of turning insert. The greater chip deformation indicates more work done, thus the more cutting heat taken away.
Vibration Frequency Analytical Formula and Parameter Sensitivity Analysis for Rocking Mass Gyroscope
Authors: Wang Xiong , Xiao Ding Bang , Wu Xue Zhong , Li Sheng Yi
Published: August 2011

Rocking-Mass Gyroscope (RMG) is a dual-axial symmetry vibrating mass gyroscope, whose operational modes are completely uniform, and values of frequency are equal. RMG has the potential to be the gyroscope with high sensitivity. Predicting the frequencies for the operational modes of RMG is critical. The natural frequency analytical formula of RMG is developed by using the assumed modal method and vector composition method. The FEM simulations and experiments validate the analytical formula. The sensitivities of natural frequency to different parameters are also analyzed. The presented results provide references for optimization design of RMG.
Research for RBF Neural Networks Modeling Accuracy of Determining the Basis Function Center Based on Clustering Methods
Authors: Zhu Jian Min , Du Peng , Fu Ting Ting
Published: August 2011

The radial basis function (RBF) neural network is superior to other neural network on the aspects of approximation ability, classification ability, learning speed and global optimization etc., it has been widely applied as feedforward networks, its performance critically rely on the choice of RBF centers of network hidden layer node. K-means clustering, as a commonly method used on determining RBF center, has low neural network generalization ability, due to its clustering results are not sensitive to initial conditions and ignoring the influence of dependent variable. In view of this problem, fuzzy clustering and grey relational clustering methods are proposed to substitute K-means clustering, RBF center is determined by the results of fuzzy clustering or grey relational clustering, and some researches of RBF neural networks modeling accuracy are done. Practical modeling cases demonstrate that the modeling accuracy of fuzzy clustering RBF neural networks and grey relational clustering RBF neural networks are significantly better than K-means clustering RBF neural networks, applying of fuzzy clustering or grey relational clustering to determine the basis function center of RBF neural networks hidden layer node is feasible and effective.
Design and Analysis of a Distributed Multi-Leaves and Large-Deformation Flexible Hooke Hinge
Authors: Sun Wei , Zhang Xian Min , Wang Nian Feng , Chen Liang , Liang Ji Min
Published: August 2011

Flexible hinge is a typical flexible element in compliant mechanisms. But in the micro area, the design of flexible Hook hinge is rare. Compared with the traditional gap-type flexure hinges, flexure hinges with curve leaf are more prone to large deformation in functions direction under the load. And through the rational design, overall error of whole body with flexure hinges with curve leaf would be reduced to a minimum. So this article uses the curve leaf as the basic unit to construct a distributed multi-leaves and large-deformation flexible Hooke hinge. In view of the hinge structure is complex and very difficult to get accurate model, the model of flexible hinge Hook is establish by pseudo-rigid method to analysis the deformation of flexible hinge Hook under pure torque load. Theoretical analysis and nonlinear finite element analysis results are very close, proved that the construction of pseudo-rigid body model is correct. The results also show that this new type of distributed multi-leaves and large-deformation flexible Hooke hinge can provide the larger two-dimensional rotating schedule, and center drift of rotation is small. So this flexible Hooke hinge is a new type of large deformation flexible Hook hinge and line with the basic rotation characteristics of Hooke hinge.
Analysis about the Independent College Students are Examined in Using the Library
Authors: Wang Yan Hong
Published: August 2011

We don’t pay attention to this question that library hasn’t been used by the College students in the university. From the situation of the independent college students in using library, this article elaborated the necessity and practicability about the college students use library will be examined. The ultimate aim is to cultivate the habits and ability of independent college students in using the library. The overall quality of college students can be raised at the same time.
A High–G Metal Capacitive Microaccelerometer with Round Proof Mass Supported by Multi-Beam
Authors: Zhang Yun Kui , Cui Feng , Wan Zhen , Li Kai , Liu Wu , Zhang Wei Ping
Published: August 2011

In this paper, differential capacitors sandwiched structure of a high-G capacitive microaccelerometer with round metal proof mass supported by multi-beam and its characteristic are presented. The operation principle and built-in self-calibration and self-test functions are described. The fabrication process and the fabricated chip of the microaccelerometer based on UV-LIGA technology are reported. The detection and closed-loop control circuits of the microaccelerometer are designed and calibrated. The range of the detection channel is ±6pF, the sensitivity is 89.3mV/pF, and the linearity is 2.59%.
Numerical Simulation of Gasoline Blending with Two Different Mixing Systems
Authors: Chen Song Ying , Xie Fu Chao , Mao Jun Jie
Published: August 2011

Based on two different mixing systems: Rotary Jet Mixing (RJM) system and side-entering agitator, two kinds of three-dimensional gasoline components mixing models are established. The incompressible Reynolds equation is selected as the momentum equation and the algorithm of SIMPLE is used to simulate the jet facility. To get the mixing time, moving mesh and the standard k-ε turbulent model has been employed in the multiphase unsteady flow. The results show that the dead areas of RJM are less than side-entering agitator, and the mixing effects are much better. Furthermore, the mixing time of RJM is only 58.2s, which is 69.7% of Side-entering Agitator.
Study of Material Motion Law in Horizontal Circling Vibrating Dryer
Authors: Zhang Zhen Wei , Zhang Hong Bo , Zhang Cheng
Published: August 2011

This article focuses on the topic of material real running mode in order to put forward the theoretical reference for the structure optimization and equipment commissioning. The authors analyzed the operational regularity of loose material in horizontal circling vibrating dryer, and then established the mathematical model of the material running law and time in the single layer plate. The thesis simulated the material operational time to any position by programming, and represented that the simulation result had the good agreement with the measured data. The conclusions of this thesis have great significance for the practical structure design of this series of equipment, which can reduce the commissioning time and optimize the structure to a large extent.
The Core of Engineering Education Is to Cultivate the Students’ Engineering Practical Ability
Authors: Miao Xian Wen , Yuan Gen Fu
Published: August 2011

The higher engineering education of our country facing the challenge of Manufacturing Globalization, the urgent mission Is to cultivate the engineers who has international vision. Considering this, engineering universities reform of personnel training mode one after another, actively learn from the advanced experience of foreign countries, promoting practical teaching to the important position. Considering the objective of cultivation of our university which is to cultivate the high-quality applied talents, putting the CDIO engineering education philosophy as a guide, this article researches the problems such as practice teaching position and how to cultivate the Engineering consciousness, engineering practice and innovative ability of students in each teaching process of engineer training.
Orthogonal Test and Multi-Element Linear Regression Analysis of Compressive Strength of Nanometer Silicon Cemented Soil
Authors: Wang Li Feng
Published: August 2011

Cement-stabilized soil has been widely used to ground treatment, tracing of foundation pit, water resistance. Additives in cemented soil play an important role in improving its basic properties of cemented soil. In this paper, a new kind of additive, Nanometer Silicon Oxide (SiO2-x), was incorporated into cemented soil. Undrained triaxial compression tests were performed to discuss the reinforced effect of the nanometer silicon on the strength property of the cemented soil. Four main factors that influence the compressive strength of the nanometer silicon cemented soil (NCS) are considered: cement content, nanometer material content, confining pressure, and water\cement ratio. Based on orthogonal tests, the paper analyzed quantitatively the main influence factors of the compression strength of NCS and presented the optimum mix combination. A linear regression model for the compression strength were proposed. Finally, some conclusions have been achieved.
Research on Parallel Computation Architecture Based on Object Computing Network
Authors: Cao Zhen Nan , Shen Bo
Published: August 2011

In this paper, a multi-body system dynamics problem is considered as a complex system modeling and computation problem. A parallel programming model and its execution environment are designed to reduce model complexity and to improve computational speed. In this architecture, the problem is divided into two levels: 1. Find a parallel mathematical algorithm to describe the behavior of this multi-body system. 2. Build a unified programming language that could leverage many different pieces of computational resources, such as symbolic computing, and numerical libraries. To tackle the first level, Space-Time Finite Element Method (FEM) is applied. The Space-Time FEM formats of Newton-Euler formula is given, as well as its constraint formula. This algorithm has avoided the loop operation during the time field solving. To tackle the second level, a network-based functional programming language - Object Computing Network (OCN) is designed. OCN is inspired by Object-Process Methodology (OPM). In OCN, every computation behavior is treated as a function, which is constructed by a three element set: {Var, Rule. Condition}. Three basic patterns - Branching, Synchronizing, Merging are given in OCN to prove the flexibility of OCN. An communication interface is designed in OCN to connect different programming languages together. Two multi-body system dynamics computing models - Semi-discretization method and Space-Time discretization method - are constructed with OCN, and a significant contrast in task parallelization is shown by different OCN models.
Synthesis and Properties of Butyl Rubber Produced by Solution Polymerization
Authors: Li Shu Xin , Wu Yi Bo , Shang Yu Wei , Guo Wen Li , Lian Hui Qin
Published: August 2011

Butyl rubber was synthesis by solution process in hexane-chloromethane mixed solvent using ethylaluminium sesquichloride/water as initiating system The product has comparable properties with BK1675(solution process) and EXXON268（slurry process）in terms of molecular, molecular distribution, unsaturated degree as well as processing properties of Mooney viscosity, vulcanization, tensile properties. The solution method will open up a new way to produce butyl rubber in China.
Research on Underwater Target Tracking Based on Contour Detection
Authors: Zhang Ming Jun , Wan Yuan Yuan , Chu Zhen Zhong
Published: August 2011

The traditional centroid tracking method over-relies on the accuracy of segment, which easily lead to loss of underwater moving target. This paper presents an object tracking method based on circular contour extraction, combining region feature and contour feature. Through the correction to circle features, the problem of multiple solutions causing by Hough transform circle detection is avoided. A new motion prediction model is constructed to make up the deficiency that three-order motion prediction model has disadvantage of high dimension and large calculation. The predicted position of object centroid is updated and corrected by circle contour, forming prediction-measurement-updating closed-loop target tracking system. To reduce system processing time, on the premise of the tracking accuracy, a dynamic detection method based on target state prediction model is proposed. The results of contour extraction and underwater moving target experiments demonstrate the effectiveness of the proposed method.
Nanoscale Particles Enhanced Gold Plating
Authors: Song Jian , Koch Christian , Wang Liang Liang , Stopic Srecko , Bogovic Jelena , Friedrich Bernd , Möbius Andreas , Fuhrmann Axel
Published: August 2011

Using precious metals as plating materials is an effective measure to avoid failures of electrical contacts caused by fretting. When using precious metals, such as gold, one of the limitations to their lifetime is the wear resistance. In order to improve the wear resistance of gold plates, gold alloy is usually used. Instead of alloying elements, nanoscale particles of metal oxides were used for the modification of plates in our investigation. Some of the nanoscale particles show considerable impact on the performance of plates for electrical contacts. This paper shows the first results and new challenges when using nanoscale particles for electroplating.
A Security Scheme Research of the Internet of Things Based on the SA/NIA Architecture
Authors: Sun Hong Feng , Li Ying , Yang Yan Chun , Feng Liang , Zhang Hong
Published: August 2011

This paper analyses the traditional three-layer architecture of the Internet of things, proposes the SA/NIA five-layer architecture from the perspective of security based on two lower layers (Sensing layer, Access layer) and three higher layers (Network layer, Intermediary layer, Application layer), investigates security threats of all layers on the basis of SA/NIA and puts forward corresponding security schemes, so as to construct a safe and reliable system of the Internet of things.
A GPU Accelerated Continuous-Based Discrete Element Method for Elastodynamics Analysis
Authors: Ma Zhao Song , Feng Chun , Liu Tian Ping , Li Shi Hai
Published: August 2011

This paper presents a GPU computing algorithm, used to accelerate the Continuous-based Discrete Element Method (CDEM). Using a NVIDIA GTX VGA card, the computing speed achieved an average 650 times speedup ratio vs. Intel Core-Dual 2.66 GHz CPU. To parallelize the CDEM algorithm, the clone node force refreshing process is separated from the elemental calculation, and is replaced by a “Node Group” force assignment process, which ensures the data independence in parallel execution.
Preparation of IPNs SBS/PBMA-b-PMA and Effect of Compatibility with PVC
Authors: Wang Zhi Chao , Liu Huan , Hou Hua , Yang Zhen Xing , Wei Zhong
Published: August 2011

Interpenetrating polymer networks (IPNs) Poly(styrene-butadiene-styrene)/Poly(n-butyl methacrylate-b-methyl acrylate) (SBS/PBMA-b-PMA) was prepared by atom transfer radical polymerization (ATRP) and characterized by FT-IR, 1H NMR and TEM. The TEM photos illustrated that SBS/PBMA-b-PMA formed an obvious core-shell structure, with cross-linked SBS/PBMA core and linear PMA shell. The compatibility of IPNs with PVC was studied using SEM and DSC instruments. The mixed polymers displayed one Tg (Tg=79.4°C, ΔTg=32.5°C) and showed good compatibility. The SEM fracture surface morphologies displayed partial feature of ductile fracture different form neat PVC.
A Novel MAC Protocol with Different QoS for WMSNs Materials
Authors: Su Xiao Qin , Pan Xu Hua , Lei Zhao Ming
Published: August 2011

The adoption of wireless multimedia sensor networks (WMSNs) by applications that require complex operations, ranging from health care to industrial monitoring, has brought forward a new challenge of fulfilling the quality of service (QoS) requirements of these applications. Since the requirements depend on the applications, it would be difficult to design a single MAC that satisfies the wide range of applications. This calls for a suitable MAC protocol capable of achieving application-specific QoS. In this paper, we have proposed a novel MAC protocol with different QoS for WMSNs, which not only adapts to application oriented QoS, but also attempts to conserve energy without violating QoS-constraints. Simulation results demonstrate that the proposed protocol is capable of providing a bound latency including real-time and better throughput, at the cost of reasonable energy consumption, in comparison to other existing MAC protocols.
Analytical Method on Contact Stress of Helical Gear with Asymmetric Involutes
Authors: Li Ning , Li Wei , Liu Ning , Liu Hua Gang
Published: August 2011

Helical gear with asymmetric involutes is a new kind gear which driving side surface is large pressure angle profile. The numbers of meshing tooth are discussed during helical gear pair meshing process, thus the length of total contact lines is determined easily. It is difficult to calculate contact stress by existing formula because this kind gear is non-standard. A calculating formula is derived which can calculate contact stress of helical gear with asymmetric involutes in this paper. A computer’s software is written in order to calculate instantaneous contact stress of contact line. Contact stress is compared between symmetric helical gear and asymmetric helical gear.
Finite Element Stress Analysis on Structure of Hydraulic Support
Authors: Cao Lian Min , Zeng Qing Liang , Xiao Xing Yuan , Cui Jing
Published: August 2011

This paper mainly has stress analysis on the structure of hydraulic support, the analysis results largely reflect the force characteristics of support. The method using the finite element can deal with the structure strength question that the conventional mechanical method can not deal with and makes the result more safe and reliable.
Influences of Doping Mg Ion on Luminescent Properties of Tb Complex Material
Authors: Tai Xi Shi
Published: August 2011

A new Tb (III) complex luminescent material has been synthesized. And it was characterized by infrared spectrum. The luminescent properties of the above luminescent material were investigated in solid and in ethanol, methanol and DMSO solutions. The solvent factors and the doping different concentration of Mg (II) ion influencing the fluorescent intensity are discussed. The results show that both the solvents and the doping different concentration of Mg (II) ion could weaken the luminescent intensity of Tb (III) complex luminescent material.
Dynamic Transmission Experiment Research of Underground Heat Storage
Authors: Wang Xi , Liu Bin Chao , Guan Hong Yu , Cheng Zhi Wen , Li Hong Ren , Jiang Yan
Published: August 2011

The circular layout of the heat transfer soil tank experiments on the dynamic transmission of underground storage mechanism. By analyzing and comparing the dynamic and static, with or without heat shield of the storage conditions, explore ways to make a favorable energy storage ,which has better effect on energy injected and preservation. The results show that, compared to the static continuous loading , intermittent loading and storage with heat shield are more conducive to the storage of energy injected and improve the ability of cohesion of temperature field; controlling the ratio of the heat for the heat shield to the total load is the key issues on application of heat screen.
Synthesis and Luminescent Properties of Magnesium Complex with Schiff-Base Ligands
Authors: Du Lian Cai
Published: August 2011

Two new Schiff-base ligands and their magnesium complexes were prepared by the reaction of magnesium ion with 2-acetyl-1-naphthol-1,2-diaminopropane (complex 1) and 2-acetyl-1-naphthol-N,N-bis(3-aminopropyl)methylamine (complex 2) in ethanol solution, respectively. The luminescent properties of two novel magnesium complexes were studied in solid and in ethanol, methanol and DMSO solutions. The results show that both complex 1 and complex 2 have strong blue luminescence. The organic solvent could influence the luminescence of complex (1) and a complex (2).
Discussing on Biochemical Pathway of Anaerobic Fermentation for Hydrogen and Methane Producition by Eupatorium Adenophorum Spreng Based on Biochemical Materials
Authors: Yin Fang , Zhang Wu Di , Liu Shi Qing , Li Jian Chang , Xu Rui , Chen Yu Bao
Published: August 2011

The biochemical pathway of fermentation for methane and hydrogen production by Eupatorium adenophorum Spreng （E. adenophorum） is different from only methane production, only hydrogen production, or methane production followed by hydrogen production. This paper is focused on biochemical metabolic mechanism of relationship between methane and hydrogen production, in order that it provide theoretical basis for utilization of biomass anaerobic fermentation in the future.
Light Trapping in Monocrystalline Si Solar Cells Using Back–Side Diffraction Gratings
Authors: Rothemund Ralph , Umundum Thomas , Meinhardt Gerald , Hingerl Kurt , Fromherz Thomas , Jantsch Wolfgang
Published: August 2011

Back–side diffraction gratings enhance a solar cell’s near–band–gap response by diffracting light into higher orders and thereby reducing front–side escape losses. The resulting increased photon absorption and carrier generation improves short–circuit current densities and solar cell efficiencies. Combining rigorous coupled–wave analysis and ray tracing yields a three–dimensional, polarization sensitive optical model to calculate Si absorbance, front–side and back–side losses. For industrially used, pyramidally textured, 180 μm Si solar cells with 85 nm SiNxanti–reflection coating, the application of an optimized back–side grating enhances the short–circuit current density by ≈ +1 mA/cm2, a relative increase of ≈ +2.7 %.
Application of Double Crucible in Cz Si Crystal Growth
Authors: Prostomolotov A.I. , Verezub N.A.
Published: August 2011

The numerical modeling of melt flow, heat transfer and impurity (phosphorus) diffusion in the double crucible of "Redmet-90M" Cz puller was carried out in an application to a 200 mm diameter Si single crystal growth. The double crucible consists of two coaxial crucibles having different sizes: 490 mm (external) and 300 mm (internal) inner diameters. The bottom of internal crucible has a central hole of Do = 6 and 12 mm diameter for melt inflow from the external crucible. During crystal pulling the granulated Si was added in the external crucible and a melt of the internal crucible was doped by phosphorus. Three-dimensional features of a rotating melt flow affecting on heat transfer and impurity diffusion in the internal crucible were analyzed. In particular, the melt precession and thermal asymmetry near the liquid-solid interface (LSI) in the internal crucible are discussed. It is shown that a significant phosphorus losses caused by its evaporation from a melt surface may be compensated by additional phosphorus doping in the internal crucible.
Geographic determinants of copper and molybdenum concentrations in serum at the end of the grazing season and associations with reproductive performance in beef cows from western Canada
Authors: Van De Weyer Leanne , Waldner Cheryl
Published: August 2011

Van De Weyer, L. M. and Waldner, C. L. 2011. Geographic determinants of copper and molybdenum concentrations in serum at the end of the grazing season and associations with reproductive performance in beef cows from western Canada. Can. J. Anim. Sci. 91: 423–431. Serum concentrations of Cu and Mo were measured at the end of the summer grazing season in an observational field study of 783 breeding females from 66 cow-calf herds located in western Canada. The mean Cu concentration was 0.82 ppm (S, 0.30 ppm) and the mean Mo concentration was 0.056 ppm (S, 0.055 ppm). Serum Cu concentration differed across ecoregions (P=0.013). Serum Mo concentrations varied by ecoregion (P =0.002), soil type (P =0.011), soil color (P=0.018), and total precipitation during the growing season (P =0.004). Copper and Mo serum concentrations at the end of the grazing season were not associated with reproductive outcomes. Herd location is an important determinant of the risk of primary and secondary Cu deficiency and can inform the need for trace mineral testing of feed samples as well as supplementation.
Estudos cognitivos em ciência da informação
Authors: Borges Mônica Erichsen Nassif , Cabral Ana Maria Rezende , Lima Gercina Ângela Borem de Oliveira , Dumont Lígia Maria Moreira , Naves Madalena Martins Lopes
Published: August 2011

O estudo da influência das Ciências Cognitivas na Ciência da Informação. A Ciência da Informação, que tem como objetos de estudo a informação e o conhecimento, discute-os sob vários pontos de vista, sendo um deles, o cognitivo. Observa-se que os conceitos não têm sido adequadamente discutidos à luz das Ciências Cognitivas, apesar da Ciência da Informação sofrer muitas influências daquela disciplina. Em função dessas questões, estruturou-se, na Escola de Ciência da Informação – ECI da Universidade Federal de Minas Gerais - UFMG, o Grupo de Pesquisa “Estudos Cognitivos em Ciência da Informação” – GECCI. Neste trabalho, marco inicial das discussões do grupo, tem-se o objetivo de discutir as relações da Ciência da Informação com as Ciências Cognitivas. Para melhor compreensão desse relacionamento, serão apresentadas as principais vertentes das ciências cognitivas, contextualizados os seus aspectos que têm influenciado a Ciência da Informação e as perspectivas futuras para o relacionamento entre as duas disciplinas.
Thermodynamics and kinetics of the hydrolysis of atmospherically relevant organonitrates and organosulfates
Authors: Hu K. S. , Darer A. I. , Elrod M. J.
Published: August 2011

Abstract. The presence of alcohol, organonitrate, and organosulfate species related to the gaseous precursor isoprene in ambient secondary organic aerosol (SOA) has stimulated investigations of the nature of SOA-phase chemical processing. Recent work has suggested that certain isoprene-derived organonitrates are able to efficiently convert to organosulfates and alcohols on ambient SOA. In order to better understand the structure activity relationships previously observed for the isoprene-derived organonitrates and organosulfates, the hydrolysis reactions of a number of monofunctional and difunctional organonitrates and organosulfates with varying carbon substitution properties were investigated. Nuclear magnetic resonance techniques were used to study the bulk phase aqueous reactions of these organonitrates and organosulfates in order to determine hydrolysis reaction rate and, in some cases, thermodynamics information. Electronic structure calculations were also carried out to determine the enthalpy of hydrolysis for these species, and for the previously studied isoprene-derived species. The results suggest that while organonitrates and organosulfates are thermodynamically unstable with respect to the corresponding alcohols at standard state, only the tertiary organonitrates (and perhaps some tertiary organosulfates) are able to efficiently hydrolyze on SOA timescales and acidities.
Ozone-driven daytime formation of secondary organic aerosol containing carboxylic acid groups and alkane groups
Authors: Liu S. , Day D. A. , Shields J. E. , Russell L. M.
Published: August 2011

Abstract. Carboxylic acids are present in substantial quantities in atmospheric particles, and they play an important role in the physical and chemical properties of aerosol particles. During measurements in coastal California in the summer of 2009, carboxylic acid functional groups were exclusively associated with a fossil fuel combustion factor derived from factor analysis of Fourier transform infrared spectroscopic measurements and closely correlated with oxygenated organic factors from aerosol mass spectrometry measurements. The high fraction of acid groups and the high ratio of oxygen to carbon in this factor suggest that this factor is composed of secondary organic aerosol (SOA) products of combustion emissions from the upwind industrial region (the ports of Los Angeles and Long Beach). Another indication of the photochemically-driven secondary formation of this combustion-emitted organic mass (OM) was the daytime increase in the concentrations of acid groups and the combustion factors. This daytime increase closely tracked the O3 mixing ratio with a correlation coefficient of 0.7, indicating O3 was closely associated with the SOA maximum and thus likely the oxidant that resulted in acid group formation. Using a pseudo-Lagrangian framework to interpret this daytime increase of carboxylic acid groups and the combustion factors, we estimate that the carboxylic acid groups formed in a 12-h daytime period of one day ("Today's SOA") accounted for 25–33 % of the measured carboxylic acid group mass, while the remaining 67–75 % (of the carboxylic acid group mass) was likely formed 1–3 days previously (the "Background SOA"). A similar estimate of the daytime increase in the combustion factors suggests that "Today's SOA" and the "Background SOA" respectively contributed 25–50 % and 50–75 % of the combustion factor (the "Total SOA"), for a "Total SOA" contribution to the OM of 60 % for the project average. Further, size-resolved spectrometric and spectroscopic characterization of the particle OM indicate that the majority of the OM formed by condensation of gas-phase oxidation products. This unique set of measurements and methods to quantify and characterize photochemically and ozone-linked carboxylic acid group formation provide independent and consistent assessments of the secondary fraction of OM, which could result from second generation products of the oxidation of gas-phase alkane (molecules).
Hygroscopic properties of the ambient aerosol in southern Sweden – a two year study
Authors: Fors E. O. , Swietlicki E. , Svenningsson B. , Kristensson A. , Frank G. P. , Sporre M.
Published: August 2011

Abstract. The hygroscopic growth of the atmospheric aerosol is a critical parameter for quantifying the anthropogenic radiative forcing. Until now, there has been a lack of long term measurements due to limitations in instrumental techniques. In this work, for the first time the seasonal variation of the hygroscopic properties of a continental background aerosol has been described, based on more than two years of continuous measurements. In addition to this, the diurnal variation of the hygroscopic growth has been investigated, as well as the seasonal variation in CCN concentration. These physical properties of the aerosol have been measured with a Hygroscopic Tandem Differential Mobility Analyzer (H-TDMA), a Differential Mobility Particle Sizer (DMPS), and a Cloud Condensation Nuclei Counter (CCNC). The results show that smaller particles are generally less hygroscopic than larger ones, and that there is a clear difference in the hygroscopic properties between the Aitken and the accumulation mode. A seasonal cycle was found for all particle sizes. In general, the average hygroscopic growth is lower during wintertime, due to an increase in the relative abundance of less hygroscopic or barely hygroscopic particles. Monthly averages showed that the hygroscopic growth factors of the two dominating hygroscopic modes (one barely hygroscopic and one more hygroscopic) were relatively stable. The hygroscopic growth additionally showed a diurnal cycle, with higher growth factors during day time. CCN predictions based on H-TDMA data underpredicted the activated CCN number concentration with 7 % for a 1 % water supersaturation ratio. The underprediction increases with decreasing s, most likely due to a combination of measurement and modeling uncertainties. It was found that although the aerosol is often externally mixed, recalculating to an internal mixture with respect to hygroscopicity did not change the CCN concentration as a function of supersaturation significantly.
The comparison of MODIS-Aqua (C5) and CALIOP (V2 & V3) aerosol optical depth
Authors: Redemann J. , Vaughan M. A. , Zhang Q. , Shinozuka Y. , Russell P. B. , Livingston J. M. , Kacenelenbogen M. , Remer L. A.
Published: August 2011

Abstract. We assess the consistency between instantaneously collocated level-2 aerosol optical depth (AOD) retrievals from MODIS-Aqua (C5) and CALIOP (Version 2 & 3), comparing the standard MODIS AOD (MYD04_L2) data to the AOD calculated from CALIOP aerosol extinction profiles for both the previous release (V2) and the latest release (V3) of CALIOP data. Based on data collected in January 2007, we investigate the most useful criteria for screening the MODIS and CALIOP retrievals to achieve the best agreement between the two data sets. Applying these criteria to eight months of data (January, April, July, October 2007 and 2009), we find an order of magnitude increase for the CALIOP V3 data density (by comparison to V2), that is generally accompanied by equal or better agreement with MODIS AOD. Differences in global, monthly mean, over-ocean AOD (532 nm) between CALIOP and MODIS range between 0.03 and 0.04 for CALIOP V3, with CALIOP generally biased low, when all available data from both sensors are considered. Root-mean-squares (RMS) differences in instantaneously collocated AOD retrievals by the two instruments are reduced from values ranging between 0.14 and 0.19 using the unscreened V3 data to values ranging from 0.09 to 0.1 for the screened data. A restriction to scenes with cloud fractions less than 1 % (as defined in the MODIS aerosol retrievals) generally results in improved correlation (R2 > 0.5), except for the month of July when correlations remain relatively lower. Regional assessments show hot spots in disagreement between the two sensors in Asian outflow during April and off the coast of South Africa in July.
A new multi-gas constrained model of trace gas non-homogeneous transport in firn: evaluation and behavior at eleven polar sites
Authors: Witrant E. , Martinerie P. , Hogan C. , Laube J. C. , Kawamura K. , Capron E. , Montzka S. A. , Dlugokencky E. J. , Etheridge D. , Blunier T. , Sturges W. T.
Published: August 2011

Abstract. Insoluble trace gases are trapped in polar ice at the firn-ice transition, at approximately 50 to 100 m below the surface, depending primarily on the site temperature and snow accumulation. Due to the different time scales for snow accumulation versus diffusion of gases through the snowpack, age differences between gases and the ice in which they are "trapped" can be large; e.g. several thousand years in central Antarctica (a low snow accumulation area). Models of trace gas diffusion in polar firn are used to relate firn air and ice core records of trace gases to their atmospheric history. We propose a new diffusion model based on the following contributions. First, the airflow transport model is revised in a poromechanics framework with specific emphasis on the non-homogeneous properties (convective layer, depth-dependent diffusivity and lock-in zone) and an almost-stagnant behavior described by Darcy's law (gravity effect). We then derive a non-linear least square multi-gas optimization scheme to calculate the effective firn diffusivity (automatic diffusivity tuning). The improvements associated with the additional constraints gained by the multi-gas approach are investigated (up to eleven gases for a single site are included in the optimization process). The model is applied to measured data from four Arctic (Devon Island, NEEM, North GRIP, Summit) and seven Antarctic (DE08, Berkner Island, Siple Dome, Dronning Maud Land, South Pole, Dome C, Vostok) sites and the depth-dependent diffusivity profiles are calculated. Among these different sites, a relationship between an increasing thickness of the lock-in zone defined from the isotopic composition of molecular nitrogen in firn air (denoted δ15N) and the snow accumulation rate is obtained, in accordance with observations. It is associated with reduced diffusivity depth-gradients in deep firn, which decreases gas density depth-gradients, at high accumulation rate sites. This has implications for the understanding of δ15N of N2 records in ice cores, in relation with past variations of the snow accumulation rate. Although the extent of layering is clearly a primary control on the thickness of the lock-in zone, our new approach that allows calculation of an estimated lock-in depth may lead to a better constraint on the age difference between the ice and entrapped gases.
Black carbon fractal morphology and short-wave radiative impact: a modelling study
Authors: Kahnert M. , Devasthale A.
Published: August 2011

Abstract. We investigate the impact of the morphological properties of freshly emitted black carbon aerosols on optical properties and on radiative forcing. To this end, we model the optical properties of fractal black carbon aggregates by use of numerically exact solutions to Maxwell's equations within a spectral range from the UVC to the mid-IR. The results are coupled to radiative transfer computations, in which we consider six realistic case studies representing different atmospheric pollution conditions and surface albedos. The spectrally integrated radiative impacts of black carbon are compared for two different fractal morphologies, which brace the range of recently reported experimental observations of black carbon fractal structures. We also gauge our results by performing corresponding calculations based on the homogeneous sphere approximation, which is commonly employed in climate models. We find that at top of atmosphere the aggregate models yield radiative impacts that can be as much as 2 times higher than those based on the homogeneous sphere approximation. An aggregate model with a low fractal dimension can predict a radiative impact that is higher than that obtained with a high fractal dimension by a factor ranging between 1.1–1.6. Although the lower end of this scale seems like a rather small effect, a closer analysis reveals that the single scattering optical properties of more compact and more lacy aggregates differ considerably. In radiative flux computations there can be a partial cancellation due to the opposing effects of differences in the optical cross sections and asymmetry parameters. However, this cancellation effect can strongly depend on atmospheric conditions and is therefore quite unpredictable. We conclude that the fractal morphology of black carbon aerosols and their fractal parameters can have a profound impact on their radiative forcing effect, and that the use of the homogeneous sphere model introduces unacceptably high biases in radiative impact studies. We emphasise that there are other potentially important morphological features that have not been addressed in the present study, such as sintering and coating of freshly emitted black carbon by films of organic material.
Simulating Southern Hemisphere extra-tropical climate variability with an idealized coupled atmosphere-ocean model
Authors: Kurzke H. , Kurgansky M. V. , Dethloff K. , Handorf D. , Olbers D. , Eden C. , Sempf M.
Published: August 2011

Abstract. The design and implementation of a simplified coupled atmosphere-ocean model over mid and high Southern Hemisphere latitudes are described. The development of the model is motivated by the clear indications of important low-frequency variability of extratropical origin in atmosphere-only models and the crucial role of atmosphere-ocean interaction in altering and shaping the climate variability on decadal and multidecadal time-scales. The basic model consists of an idealized quasi-geostrophic model of Southern Hemisphere's wintertime atmospheric circulation coupled to a general ocean circulation model with simplified physics. Model spin-up is described, some basic descriptors of the model climatology are discussed, and it is argued that the model exhibits skill in reproducing essential features of decadal and multi-decadal climate variability in the extratropical Southern Hemisphere. Notably, 1000 yr long coupled model simulations reveal sea surface temperature fluctuations on the timescale of several decades in the Antarctic Circumpolar Current region.
Natural factors of technological accidents: the case of Russia
Authors: Petrova E. G.
Published: August 2011

Abstract. The data base of technological accidents and disasters that have occurred in Russia has been created. More than 13 000 information units have been collected and analyzed. The proportion of accidents triggered by natural events (natural-technological accidents or NTA) in the total number of technological accidents as well as a part of every NTA type in the total number of NTA was estimated. About 10 percent of all accidents registered in the data base were caused by natural events; among some types of accidents this proportion is even higher. Transmission facilities with more than 90 percent of overhead lines are the most vulnerable to the impact of natural hazards. The contribution of different natural hazards was evaluated. Regions with the greatest NTA risk were revealed. The influence of natural events on the technosphere is stronger in the South of the European Russia and in the Russian Far East, which are more exposed to hurricanes, snowstorms, rainfalls, icing and other natural hazards producing NTA. The critical infrastructure needs special protection and modernization in these regions. The problem of the relationship between natural hazards and the technosphere is very complicated and needs further investigation, especially taking the expected climate changes into consideration.
Exchange Rate Misalignment and International Law
Authors: Zimmermann Claus D.
Published: August 2011

History is replete with examples where states have interfered with foreign exchange markets in order to influence exchange rates. The trade conflicts between the two world wars, for instance, were fought not only via the imposition of tariffs, but also via competitive devaluations. Since then, straightforward competitive devaluations have become a rare phenomenon; contemporary scenarios, in which exchange rate policies are criticized for their potentially protectionist impact, tend to be much more sophisticated. The exchange rate policy followed by China is certainly the outstanding, yet not exclusive, example. In recent years policymakers worldwide have criticized China for maintaining an undervalued real exchange rate as part of its strategy of export-led growth.