bluuebunny/crossref_metadata_2025 huggingface dataset:
Validity in a Jiffy: How Synthetic Validation Contributes to Personnel Selection
Authors: Oswald Frederick L. , Hough Leaetta M.
Published: August 2010

Conclusions about the effectiveness of selection systems require gathering, evaluating, weighting, and interpreting validity data, but these conclusions are obviously challenged to the extent that this process is suspect. Local validity information within the organization may be desirable but not available, and conducting a local validity study may be practically infeasible because of limited time, resources, and small sample sizes. Specific validity studies outside the organization may also be problematic if they are based on jobs or settings of questionable relevance, small sample sizes, range-restricted incumbent samples, and unreliable or content-deficient predictor and criterion measures. It is usually an understatement to say that sifting through a pile of such studies to make educated guesses about the validity of selection measures within of a specific organizational setting could be an idiosyncratic, time-consuming, and frustrating process, resulting in little confidence in any summary conclusions.
Synthetic Validity: A Great Idea Whose Time Never Came
Authors: Murphy Kevin R.
Published: August 2010

Synthetic validity is very much like monogamy. It is an idea that is universally admired but not widely practiced. The concept of synthetic validity has been around for almost 60 years (Lawshe, 1952) and it is described in virtually every testing and measurement book and every industrial and organizational (I-O) psychology textbook I have ever read. I still vividly remember my undergraduate Psychological Testing professor dismissing synthetic validity as “made-up validity.” I thought he was wrong then, and I still do. Nevertheless, it is worth asking why synthetic validity studies are so rare.
ANALYSIS ON THE EFFICIENCY OF STATISTICAL MEASURES TO IDENTIFY NETWORK STRUCTURE OF CHAOS COUPLED SYSTEMS
Authors: UEOKA YUTA , SUZUKI TOMOYA , YAMAMOTO SEIICHI
Published: August 2010

Real systems often show complex behavior due to interaction among many elements composing a large-scale network. To model and predict these systems, it is desired to estimate network structures by using only time-series data observed as behavior of systems. Although several kinds of estimation techniques have been proposed, the optimum technique might be different according to properties of systems. To analyze the possibility, we estimate interactions of chaos coupled systems by four typical types of estimation techniques. For numerical simulations, we adopt the coupled map lattice, which is a model of large-scale complex systems, and we modify it so as to control the degree of synchronization and the instability of systems by changing the coupling strength and the topology of interaction among elements. As results, we can confirm that the optimum technique depends on properties of system, and then we clarify the reason from the viewpoint of synchronization and the Lyapunov exponents. Moreover, as an application, we predict future behavior of each element with new prediction model based on estimated interactions, and we demonstrate the efficiency of this prediction method.
EFFECTS OF VEHICLE NUMBER FEEDBACK IN MULTI-ROUTE INTELLIGENT TRAFFIC SYSTEMS
Authors: DONG CHUANFEI , MA XU , WANG BINGHONG
Published: August 2010

We first study dynamics of traffic flow with real-time information and the influence of a new feedback strategy named Vehicle Number Feedback Strategy (VNFS) in a multi-route scenario in which dynamic information can be generated and displayed on the board (the board refers to a variable message sign where information on the routes is displayed) to guide road users to make a choice. In a multi-route scenario, our model incorporates the effects of adaptability into the cellular automaton models of traffic flow and simulation results adopting vehicle number feedback strategy have demonstrated high efficiency in controlling spatial distribution of traffic patterns compared with the other three information feedback strategies, i.e. Travel Time Feedback Strategy (TTFS), Mean Velocity Feedback Strategy (MVFS) and Congestion Coefficient Feedback Strategy (CCFS). We also discuss the influence of expected arrival rate (Vp) at the entrance on the average flux of each route, and we find that the flux adopting VNFS is always the largest at each Vp value among these four feedback strategies.
A STUDY ON THERMAL DEFORMATION OF AC4C ALUMINUM ALLOY CASTING MATERIAL FOR TIRE MOLD IN METAL CASTING METHOD
Authors: OH YOOL KWON , YOON HEE SUNG , YANG HO DONG
Published: August 2010

This study investigated on thermal deformation of AC4C aluminum alloy casting material for tire mold built in metal casting method. In this study, temperature, displacement and stress distributions of AC4C casting material occurred inside the mold were numerically calculated by finite element analysis (FEA). Also, temperature profiles of AC4C were experimentally measured to investigate the temperature characteristics during the solidification process in metal casting device. The result of this study revealed that the numerical result of temperature profiles predicted a rapid cooling from initial state to about 25 minutes, but the experimental result of it uniformly occurred from initial state to about 15 minutes by the phase change. However, the cooling patterns of two cases were almost similar results in the whole cooling process. Also, thermal deformation was generated by the difference of cooling temperature between the surface and inside of the casting from the results of displacement and stress distribution predicted by FEA.
EFFECT OF POROSITY ON THE FATIGUE LIFE OF CAST AC4C-T6 ALLOY FOR LCD GLASS TRANSFER ROBOT
Authors: SHIM HEE-JIN , KIM JUNG-KYU
Published: August 2010

Aluminium has good corrosion properties and a high strength to weight reduction which makes it favourable in many applications. The increased use of aluminium casting in the automotive industry does also imply that the need for design data for aluminium increases. Especially for castings, the influences of casting defects are always an issue. For this reason fatigue properties for as-cast sand and permanent mould specimens with different contents of porosity have been studied. The cast aluminium specimens of two different porosities were fatigue tested in cyclic axial test at R =-1. Prior to fatigue test specimens were examined by CT-scan and sorted into two quality groups depending on the porosity level.

The aim of this work was to investigate the fatigue life for cast AC4C-T6 alloy with different amounts of inherent porosity. An additional aim was to predict the durability for cast components with defect constrained in a specified volume of components, by using a commercial program MSC. Fatigue.
SIZE-DEPENDENT BAND-GAP AND DIELECTRIC CONSTANT OF SI NANOCRYSTALS
Authors: LI M. , LI J. C. , JIANG Q.
Published: August 2010

Based on the consideration on size-dependent temperature Tm(D) where D denotes the diameter of nanoparticles and nanowires or the thickness of thin films, the size-dependent band-gap ΔEg(D) and dielectric constant ε(D) of low dimensional materials are modeled without any adjustable parameter. The model predicts an increase of the band-gap and a decrease of dielectric constant with drop of Si nanocrystals' size. The predicted results correspond to experimental and computer simulation results of Si nanocrystals.
EFFECT OF PROCESSING CONDITION AND COMPOSITION ON THE MICROHARDNESS OF Cu-(2.5-10)vol.%Al2O3 NANOCOMPOSITE POWDER PARTICLES PRODUCED BY HIGH ENERGY MECHANICAL MILLING
Authors: MUKHTAR AAMIR , ZHANG DELIANG , KONG CHARLIE , MUNROE PAUL
Published: August 2010

Nanostructured Cu -(2.5-10 vol. %) Al 2 O 3 nanocomposites were produced using high energy mechanical milling. For the as-milled Cu - Al 2 O 3 composite powder particles having Al 2 O 3 volume fractions of 2.5% and 5%, the increase in average microhardness is significant with the increase of milling time from 12 hours to 24 hours. With the increase of the content of Al 2 O 3 nanoparticles the microhardness increases and in the range of 255HV-270HV. The milled nanocomposite powders were heat treated at 150, 300, 400 and 500°C for 1 hour, respectively, to determine the thermal stability of the powder particles as a function of annealing temperature. The average microhardness increased/decreased for the Cu - Al 2 O 3 composites after annealing at 150°C due to the dislocation density, while increasing the annealing temperature to 300°C and 400°C the average microhardness almost remained mostly unchanged. Further increasing the annealing temperature to 500°C causes significant decrease in average microhardness due to reduction in dislocation density and coarsening of Cu grains of the Cu- Al 2 O 3 composite powders produced after 24 hours of milling. This paper is to report and discuss the changes of the microhardness of the material, caused by the compositions and processing conditions, used to fabricate the Cu -(2.5-10) vol. % Al 2 O 3 nanocomposite powders.
FORMATION OF ICOSAHEDRAL CLUSTERS IN AMORPHOUS Ni-Zr ALLOY
Authors: YANG QUANWEN , ZHANG CHANGQING , PANG SHUJIE , MA CHAOLI , ZHANG TAO
Published: August 2010

Formation of icosahedral clusters in Ni 66.7 Zr 33.3 alloy during rapid solidification is studied with molecular dynamics simulations. It is found that the growth rate of the smallest icosahedral cluster (Ih13) in Ni 66.7 Zr 33.3 alloy reaches its maximum at glass transition temperature region. The Ih13 in Ni 66.7 Zr 33.3 alloy contain the retained from the higher temperatures and the new grown, which reach its maximum at about 900K as well as the new grown vertex atoms of Ih13. The ratio of new grown center atoms to the new grown vertex atoms increases with decreasing temperatures, which implies that the new Ih13 form beside original Ih13 and the icosahedral clusters coalesce to the larger ones during solidification. The stabilities of center atoms and vertex atoms of Ih13 increase with decreasing temperatures, and the stability of the center atoms becomes larger than that of vertex atoms blow 900K because of its rapid increase at glass transition temperatures. The results show that the evolutions of atomic arrangement during cooling change abruptly at glass transition region.
EFFECT OF C2H2 FLOW RATE ON THE DEPOSITION OF TI-TIC-TIC/DLC GRADIENT NANO-COMPOSITE FILM ON NITI ALLOY
Authors: MA FUQIU , LIU XILIANG , LIU DONG , LI LI , ZHANG HUAFANG , ZHENG YUFENG
Published: August 2010

Ti - TiC - TiC / DLC gradient nano-composite films have been prepared on the NiTi substrates by the technique of plasma immersion ion implantation and deposition (PIIID) combining with plasma-enhanced chemical vapor deposition (PECVD). The influence of C 2 H 2 flow rate ranging from 30sccm to 50sccm on the chemical structure, microstructure, mechanical properties and corrosion resistance of resulting thin films are investigated by XPS, XRD, friction coefficient test, nano-indentation, electrochemical corrosion test and atomic absorption spectrometry. XPS and XRD results indicate that on the outmost layer, the Ti ions are mixed with the DLC film and form TiC phase, the binding energy of C 1s and the composition concentration of TiC depend heavily on the C 2 H 2 flow rate. With the increase of C 2 H 2 flow rate, the content of TiC and the ratio of carbon sp 3/ sp 2 decreases. The nano-indentation and friction experiments indicate that the gradient composite film at 30 sccm has a higher hardness and lower friction coefficient compared with that of the bare TiNi alloy. The microscratch curve tests indicate that Ti - TiC - TiC / DLC gradient composite films have an excellent bonding property with the substrate. Based on the electrochemical measurement and ion releasing tests, we have found that the Ti - TiC - TiC / DLC gradient composite films exhibit better corrosion resistance property and higher depression ability for the Ni ion releasing from the NiTi substrate in the Hank's solution at 37°C.
EFFECT OF PRE-DEFORMATION ON DAMPING CAPACITY OF TINI/NBTI COMPOSITE
Authors: JIANG JIANG , CUI LISHAN , ZHENG YANJUN , XING TINGYONG , ZHAO XINGQING , LI YAN
Published: August 2010

The present work aims to investigate the internal friction and effect of pre-deformation on damping capacity of Nb 60 Ti 25 Ni 15 alloy, which could be considered as TiNi / NbTi metal matrix composite. The internal friction results showed that this composite possesses excellent damping behavior, which is associated with the movement of a set of abundant interfaces, such as those between the TiNi and NbTi phases, those between martensitic variants and those between martensite and parent phase. Meanwhile, the peak temperature and the width of the internal peak increased with increasing of prestrain level. It appears to be due to the release of the stored elastic strain energy, or the pinning effect by the deformed structures. Furthermore, the height of internal friction peak decreased as the prestrain level increased.
INFLUENCES OF HEAT TREATMENT ON TRANSFORMATION BEHAVIORS OF NEAR-EQUIATOMIC POROUS NITI SHAPE MEMORY ALLOY
Authors: JIANG H. C. , CHEN Y. , LIU S. W. , RONG L. J.
Published: August 2010

The pore characteristics and pore size distribution of porous near-equiatomic NiTi shape memory alloy fabricated by self-propagating high-temperature synthesis (SHS) are described in detail. The effects of different heat treatments on the transformation of porous NiTi alloy were investigated by differential scanning calorimetry (DSC), x-ray diffraction (XRD), and scanning electron microscopy (SEM). The results indicate that heat treatment had strong influences on the transformation temperatures and latent heats of transformation. When the porous alloy was annealed at 648K and 748K for 3.6ks, two steps transformation including R transformation occurred during cooling and heating and the R transformation temperatures are lower than B 2↔ B 19' transformation temperatures. However, no transformation was detected within the experimental temperature range if the porous alloy was solution treated at 1133K for 2.4ks. This novel phenomenon was the results of extensive Ti2Ni intermetallic compound precipitation. The transformation temperatures of porous NiTi alloy after annealing at 1323K for 3.6ks were much lower than those of the untreated alloy.
ESTIMATION OF MIXING EFFICIENCY OF MODEL CONCRETE MIXED IN BI-AXIAL FORCED-MIXING TYPE MIXER BY THE FLUCTUATION OF PRESSURE MEASURED ON THE BLADE
Authors: YOSHIDA MOTOAKI , HASHIMOTO CHIKANORI , WATANABE TAKESHI , MIZUGUCHI HIROYUKI
Published: August 2010

The concrete mixer possesses the basic performance "mixing efficiency", and is one of the most important construction machines on the step that manufactures concrete. The bi-axial forced-mixing type of the mixer is high and the mixing efficiency is the highest. The flow patterns of this type mixer are divided into two: the locally crossing flow and the globally circulating flow. The globally circulating flow uniformly mixes fine particle materials that differ greatly the grain size turned on and are various and cement active. The locally crossing flow contributes to "Knead" to improve the contact frequency of the cement particle and water.

In the research, concrete was assumed to be a viscous model of one phase system for the model mixer of two types with different area of the locally crossing flow, the mixing efficiency curve of the model concrete of the high viscosity and the low viscosity was a process of becoming uniform with the axial rotation, and quantification was attempted. The second research tried the quantification of the crossing flow around the blade generated when two circulating flows crossed by the pressure fluctuation of the pressure sensor installed in the surface of the blade of the mixer was attempted, and the magnitude of the crossing Flow generated in the model mixer of two types and the correlation of the mixing efficiency curve were considered.
FATIGUE DAMAGE FORMATION PROCESS OF ULTRAFINE GRAINED OXYGEN-FREE AND DEOXIDIZED LOW-PHOSPHOROUS COPPER
Authors: TESHIMA NORIHIRO , YAKUSHIJI TERUTOSHI , GOTO MASAHIRO , ANDO YOSHINORI , HAN SEUNG-ZEON , KAWAGOISHI NORIO
Published: August 2010

In order to study the fatigue damage formation process of ultrafine grained copper, fatigue tests were carried out for two samples: oxygen-free copper and deoxidized low-phosphorous copper. After the processing by equal channel angular pressing (ECAP) using eight passes, equiaxed grains with an average size of 300 nm were formed for both the samples. The formation behavior of surface damage was monitored. The effects of trace impurities on surface damage formation behavior were discussed from the viewpoints of change in surface morphological feature during stressing.
FATIGUE PROPERTIES OF ALUMINUM ALLOY (A6061-T6) WITH ULTRASONIC NANO-CRYSTAL SURFACE MODIFICATION
Authors: LEE CHAN JOO , MURAKAMI RI-ICHI , SUH CHANG MIN
Published: August 2010

The corrosion resistance of aluminum can be improved by adding alloy elements or using a surface heat treatment process. The machine quality can be confirmed by analyzing the surface roughness, the surface hardness and the residual stress. In this paper, the fatigue characteristics of A6061-T6 aluminum specimens were obtained and compared with those of the treated specimens with the UNSM (Ultrasonic Nano-Crystal Surface Modification) technology and the untreated ones by using a multi-spindle rotating bending fatigue testing machine.

The fatigue crack initiation and fatigue lives of the treated specimens with the UNSM technology was delayed and extended by the UNSM effects that are the increase of surface hardness, and the reduction of the surface roughness.
EFFECT OF FRICTIONAL HEATING ON THE PROPAGATION OF SURFACE CRACK UNDER HERTZIAN CONTACT LOADING
Authors: KIM SANG-WOO , KIM SEOCK-SAM
Published: August 2010

In this paper the frictional heating effect on the propagation of surface crack under Hertzian contact loading based on the fracture mechanics is investigated. For the theoretical analysis of this effect, we estimated stress intensity factor of surface crack -tip in shear mode under Hertzian contact sliding friction. Theoretical results showed those thermal loads (Th), Peclet number (Pe) and crack angle (β) are very important factors on the propagation of surface crack under Hertzian contact loading. When thermal load(Th) and Peclet number(Pe) are constant, maximum variable range of stress intensity factor, ΔKII, is located in the range of surface crack angle 130°~150°. Non-dimensional parameter T consisting of thermal load and peclet number for evaluating ceramic wear behavior is introduced.
AN EXPERIMENTAL STUDY AND FINITE ELEMENT ANALYSIS OF CIRCULAR DISK SHAPE OF SMC
Authors: SUH CHANG-MIN , KIM SEONG-YOUN , KIM KYUNG-RYUL
Published: August 2010

An experimental study on material characterization of SMC (Sheet Molding Compounds) compression molded parts was carried out by 3-point bending tests and creep tests. And computer simulation of optimum condition of SMC design was carried out by finite element analysis. The thicknesses of SMC specimen were 6.5, 7, 7.5 and 8mm and the angles of inclination were 0°, 2.5°, 5°, 7.5° and 10°. After static load test, the stress of SMC was different at the each condition. The influence of angles of inclination was important. The maximum stress occurred at 0°. But the more angle of inclination was big, the more maximum stress was small. The decrement was big at the range of 0° to 2.5°. The influence of thicknesses also was important. The more thickness was large, the more maximum stress was small.
DEVELOPMENT OF THE HIGH TEMPERATURE FRETTING WEAR SIMULATOR FOR STEAM GENERATOR
Authors: LEE CHOON YEOL , KIM JOONG HO , BAE JOON WOO , CHAI YOUNG SUCK
Published: August 2010

In nuclear power plant, fretting wear due to a combination of impact and sliding motions of the U-tubes against the supports and/or foreign objects caused by flow induced vibration, can make a serious problem in steam generator. A test rig, fretting wear simulator, is developed to elucidate fretting wear mechanism qualitatively and quantitatively. The realistic condition of steam generator of high temperature up to 320°C, high pressure up to 15 MPa, and water environment could be achieved by a test rig. The fretting wear simulator consists of main frame, water loop system, and control unit. Actual contact region under a realistic condition of steam generator was isolated using autoclave. Effects of various parameters such as the amounts of impact and sliding motions, applied loads and initial gaps and so forth are considered in this research. After the experiment, wear damage was measured by a three-dimensional profiler and the surface was also studied by SEM microscopically. Initial results were also presented.
FATIGUE CRACK PROPAGATION BEHAVIOR ACCORDING TOFIBER ARRAYING DIRECTION FOR LOAD DIRECTION INWOVEN CFRP COMPOSITE
Authors: CHOI JUNG-HUN , KANG MIN-SUNG , KOO JAE-MEAN , SEOK CHANG-SUNG , KIM HYUNG-ICK
Published: August 2010

The fatigue crack propagation of CFRP (carbon fiber reinforced composite material) laminates is of current interest, particularly with regard to their durability under fatigue loading. Recently, carbon fiber reinforced composite materials (Woven fabric) are widely used in various fields of engineering because of its advanced properties. Then, many researchers have studied woven fabric CFRP materials but fatigue crack propagation behaviors for composites have not been still standardized . It shows the different crack propagation behavior according to load and fiber direction. Therefore, there is a need to consider fatigue crack propagation behavior in conformity with fiber arraying direction to load direction at designing structure using woven CFRP materials. In this study, therefore, the fatigue crack propagation for plain woven CFRP composite materials was investigated under two different fiber array direction (fiber arraying direction to load : 0°, 45°). Fatigue crack propagation tests of the woven CFRP composite were conducted under sinusoidal wave-form with stress ratios of 0.3 at a frequency of 10Hz, respectively. As a result of test, fatigue crack propagation rates (da/dN) were plotted against the stress-intensity factor amplitude (ΔK) and other factor. Also we compared ΔK with other factor that considering in-plain anisotropy. All of tests of fatigue crack propagation were carried out under mode I opening loading by using compact tension specimens.
A STRUCTURAL ANALYSIS AND TOPOLOGY OPTIMIZATION ON CYLINDER BLOCK OF HEAVY DUTY DIESEL ENGIN
Authors: LEE HYUN-SEUNG , LEE YOUNG-SHIN , KIM JAE-HOON , JUN JOON-TAK , LEE JAE-OK , KIM CHUL-GOO
Published: August 2010

The heavy duty diesel engine must have a large output for maintaining excellent mobility. In this study, a three-dimensional finite element model of a heavy-duty diesel engine was developed to conduct the stress analysis by using property of CGI. The compacted graphite iron (CGI) is a material currently under study for the engine demanded for high torque, durability, stiffness, and fatigue. The FE model of the heavy duty diesel engine section consisting of four half cylinders was selected. The heavy duty diesel engine section includes a cylinder block, a cylinder head, a gasket, a liner, a bearing cap, bearing and bolts. The loading conditions of engine are pre-fit load, assembly load, and gas load. A structural analysis on the result was performed in order to optimize on the cylinder block of the diesel engine.
SURFACE CHEMICAL MODIFICATION OF CIIR RUBBER BY HIGH DENSITY PLASMA TREATMENT
Authors: KIM JONG-HYOUNG , UMEHARA NORITSUGU , KOUSAKA HIROYUKI , SHIMADA MAMORU , HASEGAWA MITSURU
Published: August 2010

This paper has reported the effect of oxygen and argon plasma treatments of CIIR rubber using Attenuated Total Reflectance (ATR) and surface energy measurements. Plasma treatment led to changes in the surface energy from 31 to 45.7 mN/m. Plasma treatment conditions influenced both the changes in surface energy and stability, and they also became more difficult to obtain good contact angle measurements. However, plasma treatments made the interfacial properties to be stabilized. ATR measurements revealed that changes in surface energy with treatment time are due mostly to increased oxygen functionality.
EFFECT OF NI/TI RATIO ON THE MICROSTRUCTURE AND MECHANICAL PROPERTIES OF MO-DOPED NITIAL INTERMETALLICS
Authors: SONG XIAOYUN , LI YAN , LI SHUSUO
Published: August 2010

The microstructures and mechanical properties of Ni 50- x Ti 43+ x Al 6 Mo 1 ( x = 0.5, 1, 1.5, 3.5, 5.5 and 7 at. %) alloys have been investigated by X-ray diffraction (XRD), scanning electron microscope (SEM) and compressive tests. We found that the variation of Ni / Ti ratio is the predominant reason for affecting the yield stress. The yield stress at room temperature of Ni -rich and Ti -rich alloys was higher than that of the equi-atomic alloy due to the strong solid solution hardening caused by the variation of Ni / Ti ratio. The size and volume fraction of Ti 2 Ni phase decreased with increasing Ni / Ti ratio. The yield stress at 600°C and 700°C increased with the increasing volume fraction of Ti 2 Ni phase due to the precipitation hardening effect. The precipitation hardening effect was weakened with increasing temperature. For the Ti -rich alloy deformed at 800°C, the yield stress deceased with the increasing of Ni / Ti ratio due to the reduced strength and unfavorable distribution of Ti 2 Ni .
MULTISCALE SIMULATION OF MICROCRACK BASED ON A NEW ADAPTIVE FINITE ELEMENT METHOD
Authors: Xu Yun , Chen Jun , Chen Dong Quan , Sun Jin Shan
Published: August 2010

In this paper, a new adaptive finite element (FE) framework based on the variational multiscale method is proposed and applied to simulate the dynamic behaviors of metal under loadings. First, the extended bridging scale method is used to couple molecular dynamics and FE. Then, macro damages evolvements of those micro defects are simulated by the adaptive FE method. Some auxiliary strategies, such as the conservative mesh remapping, failure mechanism and mesh splitting technique are also included in the adaptive FE computation. Efficiency of our method is validated by numerical experiments.
SURFACE RELAXATION INDUCED STABILITY OF LOW-SYMMYTRIC STRUCTURES OF AG CLUSTERS
Authors: LIU D. , JIANG Q.
Published: August 2010

The cohesive energies of Ag nanoclusters E c (N) in truncated octahedron (TO), icosahedron (IH) and truncated decahedron (DH) structures are evaluated through both theory and Density Function theory (DFT) simulation where N denotes the atom number. In the theoretical calculation, through relating E c (N) values to the total bond numbers of clusters, E c (N) value of IH structure is found to be the lowest at any N. In DFT simulation, E c (N) values are separately evaluated before and after geometry optimization. IH structure is always favorable to exist when clusters are un-relaxed, agreed with the theoretical calculation. When the clusters are relaxed, the structural stability becomes selective and low-symmetric TO and DH structures are respectively stable at some specific size. The reason of the difference on E c (N) values between two methods is compared. Both methods indicate that Ec(N) values of the clusters are larger than those of the corresponding bulk crystals E cb .
PHASE FIELD SIMULATION OF EQUIAXED DENDRITIC GROWTH DURING NON-ISOTHERMAL POLYCRYSTALLINE SOLIDIFICATION
Authors: LI J. J. , WANG J. C. , WU L. Y. , YANG G. C.
Published: August 2010

The non-isothermal polycrystalline solidification of a binary alloy is simulated by employing a phase field model which takes into account the heat transition and the random crystallographic orientation. The stochastic nucleation is taken into account in the simulation through the Poisson seeding algorithm and a kinetic calculation for binary melts based on the classical nucleation theory. Different microstructures are obtained under various cooling conditions. It is found that the grain structure becomes finer with increasing the cooling rate, which agrees with experimental result.
THE EFFECT OF CARBON MONOXIDE ON THE HYDROGEN PERMEABILITY OF A PALLADIUM MEMBRANE
Authors: KATOH MASAHIRO , NISHIHARA KATSUNORI , KINOUCHI KOJI , CHOHAMA KOICHI , HORIKAWA TOSHIHIDE , TOMIDA TAHEI , SOTOWA KEN-ICHIRO
Published: August 2010

Plating thin Palladium ( Pd ) film on the outer surface of a porous stainless steel tube enables very rapid hydrogen permeation with an absolute selectivity. Methane steam reforming for hydrogen production is performed in a Pd membrane reactor. In this reaction, carbon monoxide ( CO ) synthesized is known to affect hydrogen permeability. The effect on hydrogen permeability and the membrane stability were investigated. After hydrogen was flowed through Pd membrane for 1 hour, CO (1%, 10%, 100% diluted by helium) was flowed on the membrane for 1 hour, and hydrogen was re-permeated through the membrane. Under the all experiment, the temperature, the differential pressure and the flow rate of non-permeation side were 823K, 0.1 MPa and 10 ml·min-1, respectively. After the re-permeating hydrogen, the hydrogen permeation rate increased gradually. Finally the rate arrived at the constant value before CO was flowed. But the necessary time was depend on the concentration of CO . The necessary time for three concentration of CO 1%, 10%, and 100% were 30min, 60min, and 180min, respectively. The reason was that depositing carbon from CO affected to hydrogen permeability. The carbon was changed to methane by hydrogen flow and the membrane was recycled.
ANALYSIS OF OXYGENATED COMPONENT (BUTYL ETHER) AND EGR EFFECT ON A DIESEL ENGINE
Authors: CHOI SEUNG-HUN , OH YOUNG-TAIG
Published: August 2010

Potential possibility of the butyl ether (BE, oxygenates of di-ether group) was analyzed as an additives for a naturally aspirated direct injection diesel engine fuel. Engine performance and exhaust emission characteristics were analyzed by applying the commercial diesel fuel and oxygenates additives blended diesel fuels. Smoke emission decreased approximately 26% by applying the blended fuel (diesel fuel 80 vol-% + BE 20vol-%) at the engine speed of 25,000 rpm and with full engine load compared to the diesel fuel. There was none significant difference between the blended fuel and the diesel fuel on the power, torque, and brake specific energy consumption rate of the diesel engine. But, NOx emission from the blended fuel was higher than the commercial diesel fuel. As a counter plan, the EGR method was employed to reduce the NOx . Simultaneous reduction of the smoke and the NOx emission from the diesel engine was achieved by applying the BE blended fuel and the cooled EGR method.
TGA CHARACTERISTIC AND FABRICATION OF POROUS SiC CERAMICS
Authors: KIM SEONG HOON , YOON HAN KI , KIM SEON JIN , PARK YI HYUN
Published: August 2010

The long-range aim of this research is to develop porous ceramics with high strength, excellent thermal resistance and chemical stability at high temperature in environmental industry. The C f / SiC was made by hot pressing method with SiC powder whose particle size is 50nm and less on the average also Al 2 O 3, Y 2 O 3 and SiO 2 as additive. The carbon fibers of oxidation property are investigated by TGA for finding out decarburization point. As a result, decarburization point selected the specific temperature of TGA curve and the C f/ SiC composites occurred perfectly decarburization at carbon fibers so the clearly porous SiC ceramics were formed many holes of 3-5µm diameters through length direction by its reaction.
RECRYSTALLIZATION OF A NICKEL-BASE SINGLE CRYSTAL SUPERALLOY UNDER COMPRESSION
Authors: MENG J. , JIN T. , SUN X.F. , HU Z.Q.
Published: August 2010

Recrystallization behavior of a nickel-base single crystal superalloy cold-deformed by compression has been investigated. The effects of plastic strain, annealing temperature and annealing time have been studied, and recrystallization diagram has been obtained. It has been found that a very strong dependence upon temperature is evident. For the single crystal superalloy with 4.5% strain, full recrystallization has been observed when annealing at 1300°C for 1h, surface recrystallization at 1250°C for 1h, cellular recrystallization at 1150°C for 1h and no recrystallization at 1100° for 1h. With the drop of temperature, the volume fraction of γ′ phase increases, which incrementally restricts recrystallized boundary migration. With the increasing of annealing time or strain, the sensitivity of recrystallization increases. Recrystallization tendency of standard- heat-treated superalloy is weaker than that of as-cast single crystal superalloy, because standard heat treatment reduces the microsegregation, lowers the eutectic amount and forms homogeneous γ1 phase distribution, which decrease preferential nucleation site of recrystallized grain and increase the resistance of boundary migration of recrystallization.
HIGH-CYCLE FATIGUE BEHAVIOR OF AM3 NICKEL-BASE SINGLE CRYSTAL SUPERALLOY AT HIGH TEMPERATURE
Authors: SHUI L. , JIN T. , SUN X.F. , HU Z.Q.
Published: August 2010

A single crystal nickel-base superalloy with ‹001› orientation was subjected to high cycle fatigue loading at temperature of 700°C and 870°C. The tests were performed in ambient atmosphere under load control at a stress ratio R =σ min /σ max =0.1 and a frequency of 83.3 Hz on smooth specimens. In this paper, the premature initiation and rapid propagation of cracks to failure due to high frequency cyclic loading were explored. The dislocation characteristics and fracture surface observation were evaluated through scanning electron microscopy and transmission electron microscopy, respectively. The results showed that the fatigue strength at 700°C was higher than that at 870°C. At 700°C the interaction of cyclic stress with high temperature induced the precipitation of homogeneous hyperfine secondary γ′ particles, that is beneficial to fatigue strength. At 870°C, the cyclic stress led to the formation of persistent slip bands moving through the γ matrix channels and the γ′ precipitates. The morphology change of γ′ phase was not notable during the deformation at high frequency cyclic loading.
HIGH TEMPERATURE LOW CYCLE FATIGUE AND FRACTURE CHARACTERISTIC IN TWO SINGLE CRYSTAL SUPERALLOYS
Authors: YU J. J. , WANG Z. H. , SUN X. F. , JIN T. , GUAN H. R. , HU Z. Q.
Published: August 2010

Total strain controlled low cycle fatigue tests were conducted at 1173K for DD32 and SRR99 alloys. With the increase of total strain range, the stress amplitude of DD32 alloy improved more fleetly than that of SRR99 alloy. At total strain ranges less than or equal to 1.0%, the low cycle fatigue life of DD32 alloy was greater than that of SRR99 alloy. It was shown that the higher content of refractory elements in DD32 alloy resulted in a remarkable improvement of LCF properties compared to SRR99 alloy. The crack propagation perpendicular to the stress axis occurred in transgranular mode in both alloys. DD32 alloy presented more ductile character than SRR99 alloy.
CRACK-HEALING BEHAVIOR AND BENDING STRENGTH OF Al2O3/SiC COMPOSITE CERAMICS ACCORDING TO THE AMOUNT OF ADDITIVE Y2O3
Authors: NAM KI WOO
Published: August 2010

Three Al 2 O 3/ SiC composite ceramics were prepared, which included 1, 3 or 5 wt. % Y 2 O 3, and their high-temperature bending strengths and in-situ crack-healing behaviors examined. A surface elliptical-crack of about 100 µm in diameter was introduces on the specimens using a Vickers hardness indenter. From in-situ observations, the Al 2 O 3/ SiC composite ceramic with 3 wt.% Y 2 O 3 showed superior crack-healing ability than the 1 and 5 wt.% Y 2 O 3 ceramics. The as-cracked specimen with 3 wt.% Y 2 O 3 showed strength recovery on healing for 1 hr at 1473 K in air, which may have been due to the lower crack-healing temperature on the addition of 3 wt.% Y 2 O 3. The heat-resistance limit temperatures of the crack-healed Al 2 O 3/ SiC composite ceramics were 1073, 1373 and 873 K for 1, 3 and 5 wt.% Y 2 O 3, respectively.
THE EFFECT OF RESIDUAL STRESS ON THE WEAR PROPERTIES OF DLC COATINGS
Authors: JANG YOUNG-JUN , KIM SEOCK-SAM , RHA JONG-JOO
Published: August 2010

Multi-layer diamond-like carbon (DLC) coating, 150 and 220 nm thick were deposited by negative pulsed d.c. bias induced with magnetron sputtering. The objective of this research is to resolve a wear resistance in terms of DLC coating residual stress and mechanical properties. The bias was controlled from - 200 to 0 V during 10 second with point contacting controller. The surface structure was continuously fabricating to soft and hard-layer during deposition. It was shown that the compressive residual stress and hardness were 0.09, 18 GPa under multi-layer coating condition. The as-deposited DLC coating has a relatively higher wear resistance than unmodified DLC under nanoabrasive wear. It also showed that multi-layer DLC coating had no wear until 400 nN. The decreased residual stress and increased film hardness in the multi-layer coating gave a rise to increase wear resistance.
NOVEL SOL-GEL METHODS FOR PREPARATION OF CERAMIC-OXIDE COATINS
Authors: HE YEDONG , GAO WEI
Published: August 2010

This paper reviews several innovative techniques that have been developed in our labs to overcome the shortages of conventional sol-gel techniques, and discusses the technical details of preparing these ceramic coatings with controllable thickness, microstructure, composition and improved properties.
INVESTIGATION ON HIGH-TEMPERATURE OXIDIZATION OF MIRROR-QUALITY GROUND STAINLESS STEEL
Authors: KATAHIRA KAZUTOSHI , OHMORI HITOSHI , MIZUTANI MASAYOSHI , KOMOTORI JUN
Published: August 2010

To investigate the possibility of developing a new surface modification method by the combined process of ELID grinding and high-temperature oxidization, we treated ELID finished specimens and polished specimens by high-temperature oxidization in the atmosphere and performed detailed analysis to determine how the treatment would change the specimen surfaces. The ELID-series showed high quality surface roughness and excellent tribological characteristics as compared with the polished-series. The improved surface properties of the ELID-series seem to result from formation of fine, uniform structures of spinel-type multiple oxides FeCr 2 O 4 and Cr 2 O 3 on the surface by high-temperature oxidization.
EFFECTS OF COUNTERPART MATERIALS ON WEAR BEHAVIOR OF THERMALLY SPRAYED Ni-BASED SELF-FLUX ALLOY COATINGS
Authors: KIM KYUN TAK , KIM YEONG SIK
Published: August 2010

This study aims at investigating the wear behavior of thermally sprayed Ni -based self-flux alloy coatings against different counterparts. Ni -based self-flux alloy powders were flame-sprayed onto a carbon steel substrate and then heat-treated at temperature of 1000 °C. Dry sliding wear tests were performed using the sliding speeds of 0.2 and 0.8 m/s and the applied loads of 5 and 20 N. AISI 52100, Al 2 O 3, Si 3 N 4 and ZrO 2 balls were used as counterpart materials. Wear behavior of Ni -based self-flux alloy coatings against different counterparts were studied using a scanning electron microscope(SEM) and energy dispersive X-ray spectroscopy (EDX). It was revealed that wear behavior of Ni -based self-flux alloy coatings were much influenced by counterpart materials.
SHELL MATERIAL'S PERFORMANCE OF THE MICROCAPSULE FOR ELECTROLYTIC CO-DEPOSITION
Authors: LIU HUI CONG , XU XIU QING , LI WEI PING , GUO YAN HONG , ZHU LI-QUN
Published: August 2010

The shell material of microcapsules has an important effect on the electrolytic co-deposition behavior, the release of core material and the surface performance of composite coating. This paper discussed the tensile property and the stability of three shell materials including polyvinyl alcohol (PVA), gelatin and methyl cellulose (MC). It is found that these three shell materials have good mechanical strength and flexibility which are favorable to electrolytic co-deposition and stability of microcapsules in composite coating and that MC has well permeability and porosity which has a positive effect on the release of the core material in composite coating. Moreover, the study of the thermal properties and water vapor permeability of the three shell materials showed that their permeability improved with increase of temperature and humidity. In addition, the composite copper coating containing microcapsules with PVA, gelatin or MC as shell material was prepared respectively.
A LIFE PREDICTION MODEL OF THERMAL BARRIER COATINGS
Authors: NI LIYONG , LIU CHAO , ZHOU CHUNGEN
Published: August 2010

The durability and reliability of thermal barrier coatings(TBCs) have become a major concern of hot-section components due to lack of a reliable life prediction model. In this paper, it is found that the failure location of TBCs is at the TBC/TGO interface by a sequence of crack propagation and coalescence process. The critical crack length of failure samples is 8.8mm. The crack propagation rate is 3-10µm/cycle at the beginning and increases largely to 40µm/cycle near coating failure. A life prediction model based a simple fracture mechanics approach is proposed.
DEVELOPMENT AND OXIDATION RESISTANCE OF PLASMA SPRAYED Mo(Si,Al)2 COATING ON Nbss/Nb5Si3 IN SITU COMPOSITES
Authors: YAO DENDZUN , WEI HAIXIA , ZHOU CHUNGEN
Published: August 2010

A Mo ( Si , Al )2 coating is developed to protect Nb ss/ Nb 5 Si 3 in situ composite by plasma spraying. The binary layers of this coating consist of an inner interdiffusion layer surrounded by Mo ( Si , Al )2 layer with C40 crystal structure. After oxidation at 1250°C for 100h, Mo ( Si , Al )2 coating exhibited an excellent protection against oxidation and good adherence to substrate. The oxidation curve followed parabolic law and even after oxidation at high temperature for 100h, the weight gain per unit area of Mo ( Si , Al )2 coating is 8.24mg/cm2. No evident spalling of coating to substrate was observed but a continuous and compact layer of Al 2 O 3 was formed on coating surface to prevent oxidation below coating and substrate.
PREPARATION AND CHARACTERISTICS OF NIXZN(1-X)FE2O4-ENCAPSULATED HOLLOW GLASS SPHERES BY ERRITE PLATING
Authors: YU MEI , WANG CHENG , LIU JIANHUA , LI SNOGMEI , HUANG LIJIE
Published: August 2010

Hollow glass spheres was encapsulated with a layer of Ni x Zn (1- x ) Fe 2 O 4 film without using ultrasound by ferrite plating at a temperature of 80°C. The films were characterized by X-ray diffraction (XRD), optical microscopy, scanning electron microscopy (SEM) and energy dispersion spectroscopy (EDS). XRD patterns indicated the films had spinel structure. The atom ratio of nickel to iron in the films was affected by the proportion of reactants and the synthetic conditions. The saturation magnetization of the composite spheres was enhanced from 24emu/g to 60emu/g with the increase of reactants solution concentration.
PREPARATION AND LUMINESCENCE PROPERTIES OF Eu2+-ACTIVATED Ba-Six-O-N PHOSPHORS
Authors: ZHANG RUILI , NUMATA MANAKA , MAEDA TOMONORI , AKAZAWA YUJI , MURAI KEI-ICHIRO , MORIGA TOSHIHIRO
Published: August 2010

A series of oxonitridosilicates phosphors Ba - Si x - O - N / Eu 2+ ( x = Si / Ba =1~8, 5atom% Eu 2+) were synthesized using traditional solid-state reaction. For x = 2~8, the main phase of the obtained samples was Ba 3 Si 6 O 12 N 2. All Ba - Si x - O - N / Eu 2+( x = 1~8) materials could be efficiently excited in the UV to visible region(310~450 nm ) and had a green emission at 508~522 nm , making them attractive as conversion phosphors for white LED applications. With increasing x values, the emission peaks shifted to the longer wavelength region, while the emission intensity had a maximum at x = 6. The influence of the firing times was also discussed, after twice fired, there was a tendency of single-phased formed of the obtained materials and the emission intensity was greatly improved.
THERMAL BEHAVIOR OF PHOSPHATE INTERCALATED Mg/Al-LAYERED DOUBLE HYDROXIDES
Authors: SHIMAMURA AKIHIRO , KURASHINA MASASHI , KANEZAKI EIJI
Published: August 2010

The thermal behavior of Mg and Al layered double hydroxide with interlayer hydrogen phosphate (abb. as Mg / Al - HPO 4- LDH ) is investigated below 1273 K by means of XRD, TG-DTA, SEM and FT-IR. The basal spacing of Mg / Al - HPO 4- LDH decreases with increasing heating temperature stepwise in two stages; from 1.07 nm at 293 K to 0.85 nm at 333 K in the first stage and to 0.73 nm between 373 K and 443 K in the second one. The LDH becomes amorphous above 443 K until Mg 3 ( PO 4)2, MgO and MgAl 2 O 4 (spinel) appear at 1273 K. SEM images of the LDH show plate-like crystallites both before and after heating at 473 K.
ANIONIC EMULSION-MEDIATED SYNTHESIS OF ZEOLITE BETA
Authors: JIN CHAO , ZHANG YING , GAO WEI , CUI LISHAN
Published: August 2010

Well-crystallized zeolite beta is first synthesized in the anionic emulsion systems of cyclohexane/sodium dodecylbenzenesulfonate(SDBS)/pentanol/zeolite synthesis mixture. Beta materials are then characterized by XRD, SEM, and N 2-adsorption techniques. Compared to beta samples grown using the same synthesis mixture in the absence of the anionic emulsion, the as-synthesized beta presents uniform and well-defined larger crystals. Interestingly, N 2-adsorption results show that such beta sample possesses both ordered mesopores at 3.9 nm and macropores centered at 60.5 nm. These pores combined with the intricate micropores of the Beta crystal comprise the hierarchical porosity. The hierarchical pore-structured zeolite beta may have potential catalysis application in reactions involving large molecules. Additionally, control experiments are also performed to ascertain the effects of the individual emulsion components. Further synthesis study finds the transformation of zeolite beta to ZSM-5 through increasing oil contents, crystallization temperature and time.
A NAÏVE BAYES CLASSIFIER FOR WEB DOCUMENT SUMMARIES CREATED BY USING WORD SIMILARITY AND SIGNIFICANT FACTORS
Authors: PERA MARIA SOLEDAD , NG YIU-KAI
Published: August 2010

Text classification categorizes web documents in large collections into predefined classes based on their contents. Unfortunately, the classification process can be time-consuming and users are still required to spend considerable amount of time scanning through the classified web documents to identify the ones with contents that satisfy their information needs. In solving this problem, we first introduce CorSum, an extractive single-document summarization approach, which is simple and effective in performing the summarization task, since it only relies on word similarity to generate high-quality summaries. We further enhance CorSum by considering the significance factor of sentences in documents, in addition to using word-correlation factors, for document summarization. We denote the enhanced approach CorSum-SF and use the summaries generated by CorSum-SF to train a Multinomial Naïve Bayes classifier for categorizing web document summaries into predefined classes. Experimental results on the DUC-2002 and 20 Newsgroups datasets show that CorSum-SF outperforms other extractive summarization methods, and classification time (accuracy, respectively) is significantly reduced (compatible, respectively) using CorSum-SF generated summaries compared with using the entire documents. More importantly, browsing summaries, instead of entire documents, which are assigned to predefined categories, facilitates the information search process on the Web.
BLOCH-TYPE CONJECTURES AND AN EXAMPLE A THREE-FOLD OF GENERAL TYPE
Authors: PETERS CHRIS
Published: August 2010

The hypothetical existence of a good theory of mixed motives predicts many deep phenomena related to algebraic cycles. One of these, a generalization of Bloch's conjecture says that "small Hodge diamonds" go with "small Chow groups". Voisin's method [19] (which produces examples with small Chow groups) is analyzed carefully to widen its applicability. A three-fold of general type without 1- and 2-forms is exhibited for which this extension yields Bloch's generalized conjecture.
THE ALEKSANDROV–BAKELMAN–PUCCI ESTIMATES FOR SINGULAR FULLY NONLINEAR OPERATORS
Authors: JUNGES MIOTTO T.
Published: August 2010

The main scope of this paper is to obtain Aleksandrov–Bakelman–Pucci estimates (ABP estimates) for viscosity solutions of singular fully nonlinear operator, which includes the p-Laplacian operator, p > 1.