bluuebunny/crossref_metadata_2025 huggingface dataset:
EFFECT OF MULTI-WALLED CARBON NANOTUBES ON THE BIODEGRADABLE BEHAVIOR OF POLY (L-LACTIDE) IN VITRO
Authors: FENG JIANGTAO , SUI JIEHE , CHAKOLI ALI NABIPOUR , CAI WEI
Published: April 2009

Composites based on multi-walled carbon nanotubes (MWCNTs)s and poly(L-lactide) (PLLA) were prepared by using solvent casting method. Both carboxylated MWCNTs and pristine MWCNTs were considered in order to investigate the interactions between PLLA and MWCNTs and to understand the role of the filler in the biodegradability. In vitro degradation studies were performed by measurement of weight loss, FT-IR, DSC and SEM over a 30 weeks period. Pristine MWCNTs and carboxylated MWCNTs had a different effect on the degradation of PLLA. Thermal properties of MWCNTs based PLLA composites changed compared to neat PLLA. A possible mechanism of MWCNTs effect on the degradation of PLLA was discussed.
MECHANICAL PROPERTIES OF SQUEEZE INFILTRATED AS52 MAGNESIUM MATRIX COMPOSITES
Authors: PARK YONG-HA , PARK YONG-HO , PARK IK-MIN , CHO KYUNG-MOX , OAK JEONG-JUNG , KIMURA HISAMICHI
Published: April 2009

Aluminum borate whisker (9( Al 2 O 3)·( B 2 O 3)) reinforced AS52(with and without strontium modification) metal matrix composites (MMC) were fabricated by the squeeze infiltration method. Creep rupture test was carried out at 150°C and 100 MPa condition. Results showed that Alborex reinforcement and modified polygonal shape Mg 2 Si phase contributed to the enhancement of mechanical properties and creep resistance. Creep rupture time was increased 11% and minimum creep rate was decreased 17% in the composite. At the Alborex/matrix interface, uniform thin layer of MgO was formed. The initiation of micro-voids at the reinforcement/matrix or Mg 2 Si /matrix interface was followed by their growth and coalescence to macro-cracks.
MC3T3-E1 CELL RESPONSE TO PURE TITANIUM, ZIRCONIA AND NANO-HYDROXYAPATITE
Authors: LEE DONG-HWAN , HAN JUNG-SUK , YANG JAE-HO , LEE JAI-BONG , KIM DAE-JOON
Published: April 2009

Titanium, zirconia and HAp were known as good biocompatible materials for tissue engineering. Osteblastic cell response is influence by the surface topography of material and its chemical composition as well. To evaluate the influence of different chemical compositions on osteoblast-like cells the specimens were polished until they have almost identical surface roughness. The commercially pure titanium, zirconia/alumina composite and nano-sized hydroxyapatite (HAp) specimens synthesized by hydrothermal method were used to evaluate the cell attachment, proliferation and differentiation. Confocal laser microscopy was used measurement of surface roughness, and flourescence microscopy and SEM were used to evaluate initial cell attachment and morphology after 3 hours. MTS assay was performed for cell proliferation after 1, 3, 7 days and ALP assay was used for cell differentiation after 7, 10, 14 days of cell culture period. Surface topography of nano-HAp specimen was almost identical compared with those of titanium and zirconia specimen. Under this condition, proliferation and differentiation of MC3T3-E1 cells was not significantly different with those on titanium and zirconia specimen. However, cells on Nano-HAp specimen showed quicker and more active cellular reaction for attachment when measured by the expression of adhesion proteins through confocal laser microscopy. The results suggested that the new nano-sized HAp can be applied as a suitable material for skeletal tissue engineering.
THE BULK NANOCRYSTALLINE ZN PRODUCED BY MECHANICAL ATTRITION
Authors: ZHU X. K. , ZHAO K. Y. , LI C. J. , TAO J. M. , CHAN T. L. , KOCH C. C.
Published: April 2009

The purpose of experiment was to produce bulk nanocrystalline Zn by mechanical attrition. The bulk nanocrystalline Zn produced by mechanical attrition was studied. The microstructural evolution during cryomilling and subsequent room temperature milling was characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). In this paper, Nanocrystalline Zn was produced by insitu consolidation of Zn elemental powder using mechanical attrition at liquid nitrogen and room temperature. For the samples studied, the longest elongation of 65% and highest stress of 200 MPa is obtained in nanocrystalline Zn during tensile testing at the condition of strain rate (10-3 sec-1) and 20°C which is equal to 0.43 Tm (Tm is the melting temperature of pure Zn ).
MODIFICATION OF PHASE STABILITY AND MECHANICAL PROPERTIES BY THE ADDITION OF O AND Fe INTO β-Ti ALLOYS
Authors: ABDEL-HADY MOHAMED , MORINAGA MASAHIKO
Published: April 2009

Two alloy systems were designed across the β/β+α"–phase boundary. The small addition of O and Fe was found to be very effective in stabilizing the β–phase and modifying the mechanical properties. The cold rolling effect on the mechanical properties was different between the β+α" alloys and the single β–phase alloys. The presence of 20% Zr in the alloys was a reason behind the severe change of mechanical properties with β–phase stability and with cold working.
EFFECT OF SUBSTRATE THICKNESS ON NANOSTRUCTURE AND MECHANICAL PROPERTIES OF BULK NANOCRYSTALLINE Fe3Al PREPARED BY ALUMINOTHERMIC REACTION
Authors: LA PEIQING , WANG LI , ZHAO YANG , CHEN CHUNJIE
Published: April 2009

Bulk nanocrystalline Fe 3 Al materials were prepared by aluminothermic reaction on the substrates with different thickness of 5~15 mm . Grain size of the materials was measured by transmission electron microscopy (TEM) and X-ray diffraction (XRD). Compressive strength and hardness of the materials were tested. The results showed the materials consisted of amorphous and nanocrystalline phases. With the substrate thickness increasing, amount of the nanocrystalline phase increased and that of the amorphous decreased and grain size of the nanocrystalline increased and a few grains in micrometer appeared in part areas of the materials. Yield strength and hardness of the materials remarkably decreased with the substrate thickness.
MULTISCALE MODELING OF THE VACUUM ARC REMELTING PROCESS FOR THE PREDICTION ON MICROSTRUCTURE FORMATION
Authors: YUAN LANG , DJAMBAZOV GEORGI , LEE PETER D. , PERICLEOUS KOULIS
Published: April 2009

The final solidification structures of Vacuum Arc Remelting (VAR) ingots depend on the temperature distribution and fluid motion within the molten pool. In this paper, a three-dimensional multi-physics macroscale model for VAR is developed, based on the modular CFD software PHYSICA. This model is used to provide estimates of process parameters and to study complex physical phenomena, such as liquid metal flow with turbulence, heat transfer, solidification, and magnetohydrodynamics in the VAR process. The macromodel is coupled to a microscale solidification model. The micromodel combines stochastic nucleation and a modified decentred square/octahedron method to describe dendritic growth with a finite difference computation of solute diffusion. The resulting multiscale model allows prediction of the formation of microstructures in the solidifying mushy zone. This gives a better understanding of the whole VAR process from operational conditions to final ingot microstructures, as well as an essential first step in defect prediction.
FINITE ELEMENT ANALYSIS OF DEFORMATION CHARACTERISTICS IN HEAVY SLAB ROLLING
Authors: JI YO-HAN , PARK JONG-JIN , MOON CHANG-HO , CHUN MYUNG-SHIK , PARK HAE-DOO
Published: April 2009

Plastic deformation that occurs in a heavy slab during plane-strain rolling was investigated by the finite element analysis. A cylindrical pore was assumed to be located along the transverse direction of a slab. The effective strain was found to be the largest at the sub-surface layer and the smallest at the middle layer, where the shear strain developed the least. Pore closure was most difficult at the middle layer. This is where hydrostatic stress in addition to effective strain developed the least. Rolling torques, rolling forces and pressure distributions at the roll/slab interface were investigated as well, under various conditions.
STUDY ON EFFICIENT NUMERICAL SIMULATION TECHNOLOGY OF MOLD FILLING PROCESS OF CASTING
Authors: YANG LIUSHUAN , WANG XIAO , HUANG JINLIANG , ZHANG SHAOLI
Published: April 2009

The paper based on the SOLA-VOF, depended on the meaning of the equation result in the algebra and geometry, brings forward a new idea and the rapid iterative arithmetic. According to the rapid iterative arithmetic, a program of the rapid calculating method of flow field and the numerical simulation experiment using the standard casting have been made by the author. The result showed that the calculating efficiency has increased by 3~4 times than before, the accuracy equals to the SOLA-VOF, which can meet the requirements of the application.
NUMERICAL SIMULATION ON FATIGUE CRACK GROWTH OF METAL SHEET INDUCED BY LASER SHOT PEENING
Authors: ZHAO JIANFEI , ZHOU JIANZHONG , HUANG SHU , JIANG SUQIN , FAN YUJIE
Published: April 2009

Based on theoretical analysis, finite element software ABAQUS and MSC.Fatigue were used to establish the forecasting model of fatigue life for laser shot peening (LSP) process. By using a standard stretch test sample of 6061-T6 aluminium alloy, the residual stress field induced by LSP was analyzed with ABAQUS code firstly, and then the stress field model was imported into MSC.Fatigue code for the crack growth analysis. The residual stress distribution and its effect on crack propagation life induced by LSP are numerical studied, and the fatigue life is predicted. The results show that numerical simulation approach is valuable for analyzing the fatigue crack growth and influence of process parameters on fatigue life.
THE EXCHANGE-BIASING IN THE TOP-CONFIGURATION Ni80Fe20/Ir20Mn80 SYSTEM
Authors: CHEN YUAN-TSUNG
Published: April 2009

In this work, top-configuration exchange-biasing NiFe ( y )/ IrMn (90Å) systems have been investigated with three different conditions: (a) the substrate temperature ( T s ) was kept at room temperature (RT) only, (b) T s at RT with an in-plane field ( h ) = 500 Oe deposition during deposition, and (c) T s = RT with h during deposition and postdeposition annealing in the field at T A = 250° C for 1h, with the samples field cooled to RT. High resolution electron cross-sectional transmission electron microscopy (HR X-TEM) and x-ray results reveal that the IrMn (111) texturing plays a key role in the exchange-biasing field ( H ex ) and interfacial energy ( J k ). The H ex versus y result shows that H ex increases when y decreases. Since J k = H ex M s y , where M s is NiFe magnetization, it is easy to derive H ex = J k /( M s y ). Therefore, if H ex is inversely proportional to y , with J k / M s constant, we find H ex y = constant. In short, the y dependence of J k is similar to that of M s for each curve. The H c is inversely proportional to y because of the surface pinning effects from the Ta / NiFe and NiFe / IrMn interfaces. Finally, the optimal values for H ex and J k are 220 Oe and 0.075 erg/cm2, respectively.
ENHANCED NUCLEATION AND SMOOTHNESS OF NANOCRYSTALLINE DIAMOND FILMS VIA W-C GRADIENT INTERLAYER
Authors: WEI QIUPING , YU ZHIMING , MA LI , YIN DENGFENG
Published: April 2009

CVD diamond coating was deposited on to 13%wt. Co -containing tungsten cemented carbide surfaces using a hot filament chemical vapor deposition (HFCVD) to improve wear properties and performance of WC -13% wt . Co . Prior to the deposition of the diamond films, a W - C gradient intermediate layer had been sputtered on WC -13% wt . Co . The surface and cross-section morphology, phase transformation, and grain size distribution of the samples were investigated by means of field emission scanning electron microscope (SEM), X-ray diffractometer (XRD), and atomic force microscope (AFM), respectively. The results show that W - C gradient intermediate layers can effectively reduce the diffusion of Co in cemented carbide substrates during diamond deposition process, resulting high nucleation density and ultra smooth nanocrystalline diamond films.
ELECTRONIC AND ELASTIC PROPERTIES OF MgAl2O4 SPINEL AT HIGH ISOSTATIC PRESSURE: FIRST PRINCIPLE STUDY
Authors: LI MEILING , SUN FENGJIU , ZHANG PING
Published: April 2009

The calculations of mechanic and electronic properties for MgAl 2 O 4 spinel under pressure are presented by first principle. The lattice constants and internal parameters are in good agreement with the available experimental results. The calculations for bulk modulus, elastic constants, energy gaps, bond lengths for the nearest neighbor cation- O anion and their pressure dependence show an increase of bulk modulus, elastic constants, energy gaps in high symmetry and a decrease of cation- O anion bond lengths. A transition from indirect gap material to direct one is found due to applying pressure. Up to 70GPa, there is no sign of structural instability.
MICROSTRUCTURE AND MECHANICAL PROPERTIES OF ZNO FILMS ON SILICON SUBSTRATE WITH ITO BUFFER LAYER
Authors: ZOU C.-W. , GAO W.
Published: April 2009

ZnO thin films were prepared by an unbalanced magnetron sputter on silicon substrates and glass slides. An ITO layer was applied on Si substrate as a buffer layer. Microstructure and mechanical deformation behaviors of the ZnO films were investigated by XRD, SEM and nanoindentation methods. Results showed that ITO buffer layer plays an important role for ZnO heteroepitaxy growth on Si substrates. The strains at the interface induced by the lattice mismatch of Si and ZnO are repressed. As a result, ZnO films with the buffer layers showed larger grain size and better crystallinity. The hardness and modulus of ZnO films with buffer layer decreased. Continuous stiffness measurement (CSM) technique was also used to investigate the effects of buffer layer and substrate materials on the mechanical performance of the prepared ZnO films. The relationship between microstructure and mechanical properties of ZnO films are discussed based on the experimental results.
FAILURE BEHAVIORS OF FLIP CHIP SOLDER JOINTS UNDER VARIOUS LOADING CONDITIONS OF HIGH-SPEED SHEAR TEST
Authors: HA SANG-SU , HA SANG-OK , JANG JIN-KYU , KIM JONG-WOONG , LEE JONG-BUM , JUNG SEUNG-BOO
Published: April 2009

The failure behaviors of flip chip solder joints under various loading conditions of the high-speed shear test (H-SST) were investigated with an experimental and non-linear 3-dimensional finite element modeling study. The solder composition used in this study was Sn -3.0 Ag -0.5 Cu ( in wt .%). The shear forces were far greater by H-SST than by low-speed shear test (L-SST). The shear force further increased with increasing shear speed, mainly due to the high strain-rate sensitivity of the solder alloy. Brittle interfacial fractures were more easily achieved by H-SST, especially at the higher shear speed. This was discussed in terms of the relationship between the strain-rate and work-hardening effect and the resulting stress concentration at the interfacial regions
LIQUID PHASE MIGRATION IN EXTRUSION OF AQUEOUS ALUMINA PASTE FOR FREEZE-FORM EXTRUSION FABRICATION
Authors: LIU HONGJUN , LEU MING C.
Published: April 2009

Freeze-form Extrusion Fabrication (FEF) is an additive manufacturing technique that extrudes highly ceramic loaded aqueous paste along 3D contours for complex ceramic part fabrication. The phenomenon of liquid phase migration (LPM) in paste extrusion process will result in variation of liquid content in paste and consequently problems in processing and non-uniform properties of ceramic parts. It is necessary to understand the LPM phenomenon in FEF process. In this paper, the effect of liquid phase migration on extrusion of aqueous alumina paste was investigated for FEF process. The water content and extrusion force data were collected for a series of ram velocities. According to the extrusion force profiles, the extrusion process can be divided into four stages: compaction stage, transient stage, steady stage and dead zone stage. The results show that ram velocity is the key parameter for occurrence of liquid phase migration phenomenon and there is a velocity threshold above which the liquid phase migration will not happen.
DEVELOPMENT OF HOT DRAWING PROCESS FOR NITINOL TUBE
Authors: CHEN WEI , WANG H. , ZHANG LEI , TANG XIUSHAN
Published: April 2009

In recent years, Nitinol, near-equiatomic nickel-titanium alloys, have found growing applications in medical technology and joining technology, due to their special characteristics such as shape memory, superelasticity and biocompatibility. The production of Nitinol tube cost-effectively remains a technical challenge. In this paper, we describe a hot drawing process for Nitinol tube production. A Nitinol tube blank and a metal core are assembled together. The assembly is hot drawn for several passes to a final diameter. The metal core is then plastically stretched to reduce its diameter and removed from the tube. Hot drawing process has been applied to Ni 50.7 Ti and Ni 47 Ti 44 Nb 9 alloys. Nitinol tubes of 13.6 mm outer diameter and 1 mm wall thickness have been successfully produced from a tube blank of 20 mm outer diameter and 3.5 mm thickness.
LEGENDRIAN RIBBONS IN OVERTWISTED CONTACT STRUCTURES
Authors: BAADER SEBASTIAN , CIELIEBAK KAI , VOGEL THOMAS
Published: April 2009

We show that a null-homologous transverse knot K in the complement of an overtwisted disk in a contact 3-manifold is the boundary of a Legendrian ribbon if and only if it possesses a Seifert surface S such that the self-linking number of K with respect to S satisfies sl (K, S) = -χ(S). In particular, every null-homologous topological knot type in an overtwisted contact manifold can be represented by the boundary of a Legendrian ribbon. Finally, we show that a contact structure is tight if and only if every Legendrian ribbon minimizes genus in its relative homology class.
LOCAL MOVE IDENTITIES FOR THE ALEXANDER POLYNOMIALS OF HIGH-DIMENSIONAL KNOTS AND INERTIA GROUPS
Authors: OGASA EIJI
Published: April 2009

As analogues of the well-known skein relations for the Alexander and the Jones polynomials for classical links, we present three relations that hold among invariants of high dimensional knots differing by "local moves". Two are for the Alexander polynomials and the other is for the Arf-invariants, the inertia group and the bP-subgroup.
REDUCIBLE DEHN SURGERY AND THE BRIDGE NUMBER OF A KNOT
Authors: SAYARI NABIL
Published: April 2009

Let K be a knot in S3 and suppose that K(r) is a reducible manifold. Howie has proved that the number of connected summands is at most 3 [10, Corollary 5.3]. Furthermore, he showed that if K(r) is the connected sum of exactly three irreducible 3-manifolds, then K(r) = L(p1, q1)♯L(p2, q2)♯M, where L(p1, q1) and L(p2, q2) are a lens spaces and M is a ℤ-homology sphere. In this paper we study this specific case and we show that |r| ≤ (b-2)(b-1), for any knot with bridge number b.
THERMAL BUCKLING OF LAMINATED COMPOSITE PLATES WITH RANDOM GEOMETRIC AND MATERIAL PROPERTIES
Authors: VERMA VIPIN K. , SINGH B. N.
Published: April 2009

In this paper, a C o finite element has been employed for deriving an eigenvalue problem using higher order shear deformation theory. The uncertain material and geometric properties are modeled as basic random variables. A mean-centered first order perturbation technique is used to find the mean and standard derivation of the buckling temperature of laminated composite plates — subjected to a uniform temperature rise — with random material and geometric properties. The effects of the modulus ratio, fiber orientation, length-to-thickness ratio, aspect ratio and various boundary conditions on the critical temperature are examined. It is found that small variations in material and geometric properties of the composite plate significantly affect the buckling temperature of the laminated composite plate. The results have been validated with independent Monte Carlo simulation and those available in the literature.
ABOUT THE STABILITY OF NONCONSERVATIVE UNDAMPED ELASTIC SYSTEMS: SOME NEW ELEMENTS
Authors: LERBET JEAN , ABSI ELIE , RIGOLOT ALAIN
Published: April 2009

It is well-known that the domains of static stability and dynamic stability (even for a linear approach) do not match each other when the system is no more conservative and the dynamic approach is usually privileged, meaning that the dynamic stability domain is included in the static one. Following previous works proposing a new criterion of static stability of nonconservative systems and prolonging a paper of Gallina devoted to linear dynamic instability (flutter), we show in this paper some remarkable relations between the two approaches: contrary to the common thought, the new static stability criterion implies partially the dynamic one.
IMPLEMENTATION OF NON-LOCAL TOFFOLI GATE VIA CAVITY QUANTUM ELECTRODYNAMICS
Authors: LIU CHUAN-LONG , WANG YAN-WEI , ZHENG YI-ZHUANG
Published: April 2009

A scheme for realizing the non-local Toffoli gate among three spatially separated nodes through cavity quantum electrodynamics (C-QED) is presented. The scheme can obtain high fidelity in the current C-QED system. With entangled qubits as quantum channels, the operation is resistive to actual environment noise.
NONLOCALITY IMPROVES DEUTSCH ALGORITHM
Authors: NAGATA KOJI , LEE SANGKYUNG , AHN JAEWOOK
Published: April 2009

We show that the Bell inequalities lead to a new type of linear-optical Deutsch algorithms. We have considered the use of entangled photon pairs to determine probabilistically two unknown functions. The usual Deutsch algorithm determines one unknown function and exhibits a two to one speed up in a certain computation on a quantum computer rather than on a classical computer. We found that the violation of Bell locality in the Hilbert space formalism of quantum theory predicts that the proposed probabilistic Deutsch algorithm for computing two unknown functions exhibits at least a [Formula: see text] to one speed up.
EXTRACTION OF VALUE OF FUNCTION f(x) IN DEUTSCH ALGORITHM AND DEUTSCH–JOZSA ALGORITHM
Authors: DENG LI , CHEN AIXI , XU YANQIU , ZHOU SUYUN
Published: April 2009

Deutsch algorithm or Deutsch–Jozsa algorithm only needs one query to determine whether the function f(x) is constant or balanced. That is, the global property of the function f(x) is rapidly known. But these algorithms do not give the concrete value of function f(x). For the f(x), its value is also of interest. Here we propose a scheme in which the value of function f(x) can be determined. We use an entangled state as the input state and send it into quantum black box. Through performing measurement on the output state, we can exactly determine the value of f(x). Its value plus its global property enables us to thoroughly understand elementary information of f(x). Based on these informations, we can determine unitary transformations on the input state walking through quantum black box. The quantum black box becomes quantum white box to a certain extent.
FABRICATION OF 3D MICROELECTRODES FOR LITHIUM ION BATTERIES BY ELECTROPHORETIC DEPOSITION
Authors: MUNAKATA HIROKAZU , SUGIURA TAKASHI , KANAMURA KIYOSHI
Published: April 2009

An integrated array of thick Li 4 Ti 5 O 12 electrodes was fabricated by electrophoretic deposition (EPD). A precisely controlled electric field distribution by the three-electrode EPD system enabled the formation of Li 4 Ti 5 O 12 electrodes on the lines selected in the interdigitated microarray Au current collectors. The array of Li 4 Ti 5 O 12 electrodes exhibited good rate capability with larger discharge capacities than those of the electrode prepared by the sol–gel method, due to the increment of electrode thickness (0.6 μm → 4.2 μm) and the simultaneous deposition of conducting and binding materials with Li 4 Ti 5 O 12 particles. A cell consisting of the microarray Li 4 Ti 5 O 12, lithium metal anode, and poly(methyl methacrylate) gel electrolyte was successfully operated at 1.55 V and had the discharge capacity of 105.4 μ A h cm-2.
NANOCOMPOSITE ELECTRODES CONSISTING OF 3DOM CARBON WITH BIMODAL POROUS STRUCTURE AND CONDUCTING POLYMERS FOR ELECTROCHEMICAL CAPACITORS
Authors: KANAMURA KIYOSHI , WOO SANG-WOOK , DOKKO KAORU
Published: April 2009

Three-dimensionally ordered macroporous (3DOM) carbon with mesoporous walls was prepared by the colloidal crystal templating method using polystyrene (PS) and silica particles. Colloidal crystals consisting of monodispersed PS sphere (204 nm diameter) and silica particles (4–6 nm) were carbonized in Ar , and the silica was removed by etching in HF, and then 3DOM carbon with bimodal pore structure was obtained. Conducting polymers of polyaniline (PAn) and polypyrrole (PPy) were electrochemically deposited on the internal surface of macropores in 3DOM carbons. The mesopores were not closed after the deposition of the polymers. The composites were utilized as electrodes for electrochemical capacitors. The specific capacitances of prepared carbon– PAn and carbon– PPy composites were found to be 237 and 152 F g-1, respectively. The incorporation of the conducting polymers dramatically increased the charge storage capacities of the 3DOM carbon electrodes.
Magnetostratigraphy of early–middle Miocene deposits from east–west trending Alaşehir and Büyük Menderes grabens in western Turkey, and its tectonic implications
Authors: Sen Sevket , Seyitoğlu Gürol
Published: April 2009

In western Turkey, the Alaşehir and Büyük Menderes grabens form east–west trending major tectonic structures. Their sedimentary fill is important for regional tectonic models for the late Cenozoic evolution of the Aegean region. These deposits are divided into four units dated between the early Miocene and Quaternary. We studied the magnetostratigraphy of two sections in the Alaşehir graben and one in the Büyük Menderes, partly covering the first and second sedimentary units. Detailed palaeomagnetic analysis allowed us to determine ChRM component for these rocks. The Zeytinçayı river and road sections (Alaşehir graben) record several polarity reversals, which are tentatively correlated to the interval C5Cn.3n–C5ADr (approximately between 14.6–16.6 Ma) of the ATNTS2004. This correlation is also supported by palaeontology and radiometric dating of syn-extensional intrusions. In the Eycelli section (Büyük Menderes graben) only three polarity zones are recorded, and their tentative correlation with the interval of C5Bn.1r–C5Br (14.88–15.97 Ma) is in overall in agreement with the record of Eskihisar sporomorph association in this formation. These results place the initiation of the Alaşehir and Büyük Menderes grabens in the early Miocene. The palaeomagnetic declinations from the Alaşehir graben indicate about 25° anticlockwise rotation, whereas that of the Büyük Menderes graben indicate a clockwise rotation of about 30–40°. These contradictory vertical-axis rotations might be explained by detachment faults in the region. In Tertiary formations of western Turkey, contradictory block rotations are common and likely reflect thin-skinned deformation in the area rather than rigid crustal movements. Therefore, average anticlockwise rotations in western Turkey cannot be used as evidence for the model of back-arc spreading in the Aegean region.
A Silurian-Devonian marine platform-deltaic system in the San Rafael Block, Argentine Precordillera-Cuyania terrane: lithofacies and provenance
Authors: Manassero M. J. , Cingolani C. A. , Abre P.
Published: April 2009

The San Rafael Block is included as a part of the pre-Andean region, in the southern sector of the Argentine Precordillera–Cuyania terrane, within the western Gondwana margin. The Río Seco de los Castaños Formation (Upper Silurian–Lower Devonian) is one of the major marine-siliciclastic pre-Carboniferous units, and is interpreted as a distal to proximal silty platform-deltaic system. The dominant sedimentary processes were wave and storm action and the source areas were located to the east, close to the study area. The rocks are mainly of immature arkosic sandstones showing both recycled orogen and continental block provenances. Sedimentological characteristics of conglomerate-filled channels and an organic-matter-rich bed are described. X-ray diffraction analyses of the clay minerals from the sequences show that very low-grade metamorphic conditions acted during the Early Carboniferous. Geochemical analyses indicate moderate to strong weathering, and potassium metasomatism. Zr/Sc ratios lower than 22, no important enrichments of Zr, Th/Sc ratios, high Sc and Cr concentration and the Eu-anomalies indicate a provenance from a less evolved upper continental crust. T
DM
ages and ε
Nd
are within the range of the Mesoproterozoic basement and Palaeozoic supracrustal rocks from the Precordillera–Cuyania terrane. Probable sources, tectonic setting and land–sea interactions are discussed.
The Devonian System of China, with a discussion on sea-level change in South China
Authors: P. Ma Xueping , Liao Weihua , Wang Deming
Published: April 2009

Based on tectonic, lithological and biotic features, 11 regions may be recognized in the Devonian Period of China. The Junggar and Hinggan regions are characterized by thick sequences of clastic rocks associated with volcanic rocks; carbonate deposits were only local, sometimes consisting of isolated reefs. The Tarim region was characterized by intertidal sandstones on the platform and deeper water deposits in its marginal areas. The North China region was mostly barren of Devonian deposits except in some marginal areas, and the Qilian–Qaidam region was a mountainous region mostly with Middle and Upper Devonian continental sediments. Qinling Region was closely related with the South China Region in terms of faunal affinity, probably being a marginal area of the South China Plate. Western Yunnan and the major part of Xizang (including northern Xizang and the northern slope of the Himalayas) featured continuous Silurian–Devonian deposition, generally with carbonates in the Lower Devonian, and different lithologies in different regions for the Middle and Late Devonian. Qinling and Hoh Xil-Bayan Har regions were closely related with the South China Region, yielding common fossils such as brachiopods
Stringocephalus
and
Yunnanella
(=
Nayunnella
) faunas. The Devonian Period of South China comprised deposits of two large transgressive–regressive cycles: Lochkovian to Eifelian and late Eifelian to about the end of the Devonian Period.
Parasites in Emsian-Eifelian
Favosites
(Anthozoa, Tabulata) from the Holy Cross Mountains (Poland): changes of distribution within colony
Authors: Zapalski M. K.
Published: April 2009

Organisms of unknown biological affinities, assigned to the genus
Chaetosalpinx
, are known to infest Palaeozoic tabulate corals and stromatoporoids. Analysis of distribution of these parasites, performed on Emsian–Eifelian material of
Favosites goldfussi
(Anthozoa, Tabulata) from the Northern Region of the Holy Cross Mountains (Poland), shows that parasites were absent in the early astogenetical stages, and that during astogeny both the absolute number of parasites per colony and the number of parasites per polyp were increasing. The latter can reach 2.7 parasites per polyp. Preferred settling places are in corallite corners (junction of three individuals), but dense infestation also produced settlement in the corallite walls (between two individuals). Probable causes of the increase are insufficient protection by host's cnidae, insufficient immune system response, and parasite ability to adapt to the host's defences.
Upper Devonian miospore and conodont zone correlation in western Europe
Authors: Streel M.
Published: April 2009

The stratigraphical occurrence of 38 Upper Devonian miospore taxa is compared to some miospore and conodont zones in 28 intercalibrated levels. The accurate position of 15 miospore First Occurrence Biohorizons and one Last Occurrence Biohorizon in terms of the conodonts available in a few regions of western Europe is discussed in detail and their correlation evaluated.
Learning goes global
Authors: Greengard Samuel
Published: April 2009

In a world that's increasingly global and interconnected, international education is growing, changing, and evolving.
Law and technologyThe network neutrality debate hits Europe
Authors: Larouche Pierre
Published: April 2009

Differences in telecommunications regulation between the U.S. and the European Union are a key factor in viewing the network neutrality discussion from a European perspective.
ViewpointProgram committee overload in systems
Authors: Birman Ken , Schneider Fred B.
Published: April 2009

Conference program committees must adapt their review and selection process dynamics in response to evolving research cultural changes and challenges.
Debugging AJAX in production
Authors: Schrock Eric
Published: April 2009

Lacking proper browser support, what steps can we take to debug production AJAX code?
Spending Moore's dividend
Authors: Larus James
Published: April 2009

Multicore computers shift the burden of software performance from chip designers and processor architects to software developers.
Computing needs time
Authors: Lee Edward A.
Published: April 2009

The passage of time is essential to ensuring the repeatability and predictability of software and networks in cyber-physical systems.
Algorithmic systems biology
Authors: Priami Corrado
Published: April 2009

The convergence of CS and biology will serve both disciplines, providing each with greater power and relevance.
Scalable synchronous queues
Authors: Scherer William N. , Lea Doug , Scott Michael L.
Published: April 2009

In a thread-safe
concurrent queue
, consumers typically wait for producers to make data available. In a
synchronous queue
, producers similarly wait for consumers to take the data. We present two new nonblocking, contention-free synchronous queues that achieve high performance through a form of
dualism
: The underlying data structure may hold both data and, symmetrically,
requests
.

We present performance results on 16-processor SPARC and 4-processor Opteron machines. We compare our algorithms to commonly used alternatives from the literature and from the Java SE 5.0 class
java.util.concurrent.SynchronousQueue
both directly in synthetic microbenchmarks and indirectly as the core of Java's
ThreadPoolExecutor
mechanism. Our new algorithms consistently outperform the Java SE 5.0
SynchronousQueue
by factors of three in unfair mode and 14 in fair mode; this translates to factors of two and ten for the
ThreadPoolExecutor
. Our synchronous queues have been adopted for inclusion in Java 6.
Liskov wins Turing award
Authors: CACM Staff
Published: April 2009

MIT's Barbara Liskov is the 55th person, and the second woman, to win the ACM A.M. Turing Award.
Virtual machines
Authors: Bratanov Stanislav , Belenov Roman , Manovich Nikita
Published: April 2009

This article addresses a problem of performance monitoring inside virtual machines (VMs). It advocates focused monitoring of particular virtualized programs, explains the need for and the importance of such an approach to performance monitoring in virtualized execution environments, and emphasizes its benefits for virtual machine manufacturers, virtual machine users (mostly, software developers) and hardware (processor) manufacturers. The article defines the problem of in-VM performance monitoring as the ability to employ modern methods and hardware performance monitoring capabilities inside virtual machines to an extent comparable with what is being done in real environments. Unfortunately, there are numerous reasons preventing us from achieving such an ambitious goal, one of those reasons being the lack of support from virtualization engines; that is why a novel method of 'cooperative' performance data collection is disclosed. The method implies collection of performance data at physical hardware and simultaneous tracking of software states inside a virtual machine. Each statistically visible execution point of the virtualized software may then be associated with information on real hardware events. The method effectively enables time-based sampling of virtualized workloads combined with hardware event counting, is applicable to unmodified, commercially available virtual machines, and has competitive precision and overhead. The practical significance and value of the method are further illustrated by studying a parallel workload and uncovering virtualization-specific performance issues of multithreaded programs.
FlexDCP
Authors: Moreto Miquel , Cazorla Francisco J. , Ramirez Alex , Sakellariou Rizos , Valero Mateo
Published: April 2009

Current multicore architectures offer high throughput by increasing hardware resource utilization. As the number of cores in a multicore system increases, providing Quality of Service (QoS) to applications in addition to throughput is becoming an important problem.

In this work, we present FlexDCP, a framework that allows the Operating System (OS) to guarantee a QoS for each application running in a chip multiprocessor. FlexDCP directly estimates the performance of applications for different cache configurations instead of using indirect measures of performance like the number of misses. This information allows the OS to convert QoS requirements into resource assignments. Consequently, it offers more flexibility to the OS as it can optimize different QoS metrics like per-application performance or global performance metrics such as fairness, weighted speed up or throughput.

Our results show that FlexDCP is able to force applications in a workload to run at a certain percentage of their maximum performance in 94% of the cases considered, being on average 1:48% under the objective for remaining cases. When optimizing a global QoS metric like fairness, FlexDCP consistently outperforms traditional eviction policies like LRU, pseudo LRU and previous dynamic cache partitioning proposals for two-, four- and eightcore configurations. In an eight-core architecture FlexDCP obtains a fairness improvement of 10:1% over Fair, the best policy in the literature optimizing fairness.
PROPHET
Authors: Woo Dong Hyuk , Lee Hsien-Hsin S.
Published: April 2009

In this article, we propose PROPHET, a goal-oriented provisioning infrastructure based on execution history profile gathered from the cloud of distributed heterogeneous computing environment. It can autonomously tune the efficiency of a data center or satisfy the end-users' need when running network-based applications. With more tunable features provided by future multicore and many-core processors, we envision that PROPHET can be easily integrated into today's network infrastructure to provide value-added service to many of us.
HIDS
Authors: Wang Xiaoyu , Liu Hongyan , Er Daoxin
Published: April 2009

In the research of high-speed data streams, large amounts of synthetic data are needed. These days, more and more researchers focus on hierarchical multi-dimensional data streams or data sets, which is beyond the ability of traditional synthetic data generators. In this paper we propose a two-phased method to generate hierarchical multi-dimensional data streams, in which a tree-like structure is built first, and then an unlimited number of items chosen among the tree leaves according to a distribution are inserted into the stream. Our generator, HIDS, integrates all of the functions of existing data generators, and can customize the tree structure according to usersý requirements, producing tree structures such as equal-depth trees, equal-fan-out trees, balanced trees and different-fan-out trees. An experimental study using real data streams shows that HIDS can generate data streams tailored to specific applications.
Algorithm of mining sequential patterns for web personalization services
Authors: Wei Cui , Sen Wu , Yuan Zhang , Lian-Chang Chen
Published: April 2009

This paper focuses on the requirements of web personalization service for sequential patterns and sequential mining algorithms. Previous sequential mining algorithms treated sequential patterns uniformly, but individual patterns in sequences often have different importance weights. To solve this problem, we propose a new algorithm to identify weighted maximal frequent sequential patterns. First, frequency of frequent single items is used to calculate the weights of frequent sequences. Then, the frequent weighted sequence is defined, leading not only to the discovery of important maximal sequences, but the property of anti-monotony. Web usage mining has been used effectively to inform web personalization and recommender systems, and this new algorithm provides an effective method for optimizing these services. A variety of recommendation frameworks have been proposed previously, including some based on non-sequential models such as association rules, as well as sequential models. In this paper, we present a hybrid web personalization system based on clustering and contiguous sequential patterns. Our system clusters log files to determine the basic architecture of websites, and for each cluster, we use contiguous sequential pattern mining to further optimize the topologies of websites. Finally, we propose two evaluating parameters to test the performance of our system.
Pressure activates epidermal growth factor receptor leading to the induction of iNOS via NFκB and STAT3 in human proximal tubule cells
Authors: Broadbelt Nalini V. , Chen Jie , Silver Randi B. , Poppas Dix P. , Felsen Diane
Published: April 2009

Ureteral obstruction leads to increased pressure and inducible nitric oxide synthase (iNOS) expression. This study examined the involvement of epidermal growth factor (EGF) receptor (EGFR), nuclear factor-κB (NFκB), and signal transducers and activators of transcription 3 (STAT3) in iNOS induction in human proximal tubule (HKC-8) cells in response to pressure or EGF. HKC-8 cells were subjected to 60 mmHg pressure or treated with EGF for 0–36 h. iNOS was more rapidly induced in response to EGF than pressure. The addition of EGFR, NFκB, and STAT3 inhibitors significantly suppressed pressure- or EGF-stimulated iNOS mRNA and protein expression. Analysis of the activated states of EGFR, NFκB p65, and STAT3 after exposure to both stimuli demonstrated phosphorylation within 2.5 min. Anti-EGF antibody inhibited iNOS induction in pressurized HKC-8 cells, providing evidence that endogenous EGF mediates the response to pressure. In ureteral obstruction, when pressure is elevated, phosphorylated EGFR was detected in the apical surface of the renal tubules, validating the in vitro findings. These data indicate that EGFR, NFκB, and STAT3 are required for human iNOS gene induction in response to pressure or EGF, indicating a similar mechanism of activation.
Signaling of Grasp Dimension and Grasp Force in Dorsal Premotor Cortex and Primary Motor Cortex Neurons During Reach to Grasp in the Monkey
Authors: Hendrix Claudia M. , Mason Carolyn R. , Ebner Timothy J.
Published: April 2009

A fundamental question is how the CNS controls the hand with its many degrees of freedom. Several motor cortical areas, including the dorsal premotor cortex (PMd) and primary motor cortex (M1), are involved in reach to grasp. Although neurons in PMd are known to modulate in relation to the type of grasp and neurons in M1 in relation to grasp force and finger movements, whether specific parameters of whole hand shaping are encoded in the discharge of these cells has not been studied. In this study, two monkeys were trained to reach and grasp 16 objects varying in shape, size, and orientation. Grasp force was explicitly controlled, requiring the monkeys to exert either three or five levels of grasp force on each object. The animals were unable to see the objects or their hands. Single PMd and M1 neurons were recorded during the task, and cell firing was examined for modulation with object properties and grasp force. The firing of the vast majority of PMd and M1 neurons varied significantly as a function of the object presented as well as the object grasp dimension. Grasp dimension of the object was an important determinant of the firing of cells in both PMd and M1. A smaller percentage of PMd and M1 neurons were modulated by grasp force. Linear encoding was prominent with grasp force but less so with grasp dimension. The correlations with grasp dimension and grasp force were stronger in the firing of M1 than PMd neurons and across both regions the modulation with these parameters increased as reach to grasp proceeded. All PMd and M1 neurons that signaled grasp force also signaled grasp dimension, yet the two signals showed limited interactions, providing a neural substrate for the independent control of these two parameters at the behavioral level.
Acute Cholecystitis Caused by Ceftriaxone Stones in an Adult
Authors: Becker Christian D. , Fischer Robert A.
Published: April 2009

Acute cholecystitis is a major health problem. There are multiple etiologies to be considered and early recognition of the condition is important to optimize management and outcome. We report the first case in the medical literature of symptomatic acute cholecystitis triggered by ceftriaxone-associated gallbladder sludge formation and, importantly, solid ceftriaxone gallstone formation in an adult patient with underlying mineral and pigment cholecystolithiasis, necessitating cholecystectomy. This case serves as a reminder for physicians to keep this uncommon cause of cholecystolithiasis and cholecystitis in mind in patients who receive prolonged ceftriaxone therapy. These patients should be cautioned to promptly report to their physicians any signs or symptoms of cholecystitis in order to ensure timely and appropriate evaluation.
Bifurcation Analysis in a Kind of Fourth‐Order Delay Differential Equation
Authors: Cui Xiaoqian , Wei Junjie
Published: April 2009

A kind of fourth‐order delay differential equation is considered. Firstly, the linear stability is investigated by analyzing the associated characteristic equation. It is found that there are stability switches for time delay and Hopf bifurcations when time delay cross through some critical values. Then the direction and stability of the Hopf bifurcation are determined, using the
normal form method and the center manifold theorem. Finally, some numerical simulations are carried out to illustrate the analytic results.
The Staircase Structure of the Southern Brazilian Continental Shelf
Authors: Baptista M. S. , Conti L. A.
Published: April 2009

We show some evidences that the Southeastern Brazilian Continental Shelf (SBCS) has a devil′s staircase structure, with a sequence of scarps and terraces with widths that obey fractal formation
rules. Since the formation of these features is linked with the sea‐level variations, we say that the
sea level changes in an organized pulsating way. Although the proposed approach was applied in
a particular region of the Earth, it is suitable to be applied in an integrated way to other shelves
around the world, since the analyses favor the revelation of the global sea‐level variations.
The Protective Effects of Ultraviolet A1 Irradiation on Spontaneous Lupus Erythematosus-Like Skin Lesions in MRL/lpr Mice
Authors: Mikita Naoya , Kanazawa Nobuo , Yoshimasu Takashi , Ikeda Takaharu , Li Hong-jin , Yamamoto Yuki , Furukawa Fukumi
Published: April 2009

We investigated the effects of ultraviolet A1 (UVA1) irradiation on spontaneous lupus erythematosus- (LE-) like skin lesions of MRL/lpr mice, using a disease prevention model. UVA1 irradiation significantly inhibited the development of LE-like skin lesions, without obvious changes of the disease including renal disease and serum antinuclear antibody levels. Besides the massive infiltration of mast cells in the LE-like skin lesions, in the nonlesional skins, more mast cells infiltrated in the UVA1-irradiated group compared with the nonirradiated group. Although apoptotic cells were remarkably seen in the dermis of UVA1-irradiated mice, those cells were hardly detectable in the dermis of the nonirradiated mice without skin lesions. Further analysis showed that some of those apoptotic cells were mast cells. Thus, UVA1 might exert its effects, at least in part, through the induction of the apoptosis of pathogenic mast cells. Our results supported the clinical efficacy of UVA1 irradiation for skin lesions of lupus patients.