bluuebunny/crossref_metadata_2025_split huggingface dataset:
Implementation of Mechanical Twinning in a Grain Interaction Model: Application to Magnesium Alloys
Authors: Mu Sijia , Al‐Samman Talal , Mohles Volker , Gottstein Günter 
Published: June 2010

AbstractIn many materials with low crystal symmetry or low stacking fault energies, plastic deformation is accomplished not only by crystallographic slip, but also by twinning. During deformation, twinning plays two important roles. On one hand, it changes the texture evolution associated with reorientation of the twinned portion of the grains. On the other hand, the twin boundaries act as barriers to the propagation of slip and other twin systems. Therefore, to constitutively describe deformation texture evolution of the materials mentioned above, these two effects of twinning must be taken into account. The grain‐interaction (GIA) model is one of the most advanced cluster type Taylor models, and has been successfully applied to predict deformation texture evolution of cubic materials, especially of Al and its alloys. The GIA model considers the next‐neighbor grain interaction, but it only takes crystallographic slip as deformation mechanism, without twinning. In recent years, various attempts have been made to introduce twinning into deformation texture models. For example the Monte‐Carlo approach proposed by Von Houtte and advanced by Tomé as a predominant twin reorientation scheme (PTR), which reorients the selected grains fully by twinning. In the volume fraction transfer (VFT) scheme, the Euler space is partitioned into equal cells, and the volume fractions are assigned to the respective cells and their evolution is recorded with progressing deformation. Recently, the PTR scheme has been further developed as the “meso‐scale composite grain (CG)” approach, in which the twins are treated as inclusions, and secondary twins and slip are allowed to be activated inside the primary twins. In this study, we apply the PTR approach to handle twinning in the GIA model and compare the simulation results with that of the experimental data. To simply the problem we firstly ignored the hardening effect caused by twinning, which will be considered in the further work.
Influence of Texture and Grain Size on Martensitic Transformations Occurring During Low‐Cycle Fatigue of a Fine‐Grained Austenitic Stainless Steel
Authors: Poulon Angeline , Brochet Stéphanie , Glez Jean‐Christophe , Mithieux Jean‐Denis , Vogt Jean‐Bernard 
Published: June 2010

AbstractThe influence of grain size and texture on microstructural changes occurring during low‐cycle fatigue of an austenitic stainless steel are investigated (grain size of 2 and 20 µm). All the materials exhibited a strong secondary hardening at high strain range as a result of a fatigue‐induced martensitic transformation. α′ martensite is found to nucleate in austenitic grains containing a high density of dislocations but not at slip band intersections, as is usually reported for austenitic stainless steels. Considering the unstable composition of the steel studied and the decrease of the grain size, dislocations structures inside austenite grains are unchanged but cyclic solicitation promotes the induced transformation of austenitic phase. Localization of the martensite grains formed depends on the grain texture and the grain size inside which nucleus are formed.
Interaction Between Dislocations and Grain Boundaries Role in Plastic Deformation
Authors: Priester Louisette , Couzinié Jean‐Philippe , Décamps Brigitte 
Published: June 2010

AbstractSeveral proceedings have been applied to improve metals and metallic alloys mechanical properties: change of composition, microstructure, and texture changes following various thermo‐mechanical treatments. One new hope, based on the different behaviors of grain boundaries under mechanical solicitation, is emerging. The researches in this field are still in their infancy, but the present paper attempts to demonstrate that macroscopic behavior changes are likely to occur due to the modification of the grain boundary distribution in a polycrystal. This requires first to investigate the answer of individual grain boundaries to strains coming mainly from their interactions with the lattice dislocations.
The β‐to‐γ Transition in BiFeO3: A Powder Neutron Diffraction Study
Authors: Arnold Donna C. , Knight Kevin S. , Catalan Gustau , Redfern Simon A. T. , Scott James F. , Lightfoot Philip , Morrison Finlay D. 
Published: June 2010

AbstractHigh‐temperature powder neutron diffraction experiments are conducted around the reported β–γ phase transition (∼930 °C) in BiFeO3. The results demonstrate that while a small volume contraction is observed at the transition temperature, consistent with an insulator–metal transition, both the β‐ and γ‐phase of BiFeO3 exhibit orthorhombic symmetry; i.e., no further increase of symmetry occurs during this transition. The γ‐orthorhombic phase is observed to persist up to a temperature of approximately 950 °C before complete decomposition into Bi2Fe4O9 (and liquid Bi2O3), which subsequently begins to decompose at approximately 960 °C.
Nitrogen‐Doped Carbon Materials Prepared by Ammoxidation as Solid Base Catalysts for Knoevenagel Condensation and Transesterification Reactions
Authors: Kan‐nari Naokatsu , Okamura Shuhei , Fujita Shin‐ichiro , Ozaki Jun‐ichi , Arai Masahiko 
Published: June 2010

AbstractNitrogen‐doped carbon materials were prepared by ammoxidation of commercial carbon sources (carbon black and activated carbon) and applied as base catalysts for Knoevenagel and transesterification reactions. It was shown that these carbon materials were active and the activities were different depending on the ammoxidation conditions (temperature and ammonia concentration in air) and carbon sources used. The bulk, textural, and surface properties of the nitrogen‐doped carbon materials were examined by several methods to clarify possible factors determining their final catalytic activities. The activated carbon‐derived catalysts were more active than the carbon black‐derived ones. The surface area and porosity were not responsible for this difference between the two carbon sources but the difference in the reactivity with oxygen was important. The reactivity of carbon sources with oxygen should influence the doping of nitrogen onto their surfaces by ammoxidation with ammonia and air and the resulting activities as base catalysts. The catalytic activity increases with the amount of nitrogen doped and, therefore, the nitrogen doped should be responsible for the catalytic activities. In addition, the activities are maximal at a ratio of nitrogen to oxygen of around 1, suggesting the importance of cooperative functions of nitrogen and oxygen on the surface of carbons.
Examination of the Aromatic Amination Catalyzed by Palladium on Charcoal
Authors: Komáromi Anna , Novák Zoltán 
Published: June 2010

AbstractThe Buchwald–Hartwig amination of aryl halides with secondary amines and functionalized aromatic amines catalyzed by solid‐supported palladium is reported. The choices of ligand, base and solvent are crucial for the successful coupling. The amination of aromatic iodides, bromides and chlorides can be easily achieved with palladium on charcoal in the presence of a biphenylphosphane‐type ligand at 80–110 °C. In addition, the palladium on charcoal catalyst is easily separable after the reaction, and reusable several times with only small activity loss.
Copper‐Catalyzed Cross‐Dehydrogenative Coupling (CDC) of Alkynes and Benzylic CH Bonds
Authors: Correia Camille A. , Li Chao‐Jun 
Published: June 2010

AbstractThe activation of benzylic CH bonds and subsequent coupling with terminal alkynes in the presence of 2,3‐dichloro‐5,6‐dicyanoquinone (DDQ) and a catalytic amount of copper(I) triflate is presented. Good to moderate yields of disubstituted alkynes are obtained for this cross‐dehydrogenative coupling (CDC) reaction between a variety of aromatic alkynes and diphenylmethane derivatives.
A General Approach to the Synthesis of β2‐Amino Acid Derivatives via Highly Efficient Catalytic Asymmetric Hydrogenation of α‐Aminomethylacrylates
Authors: Guo Yujuan , Shao Guang , Li Lanning , Wu Wenhao , Li Ruihong , Li Jingjing , Song Jian , Qiu Liqin , Prashad Mahavir , Kwong Fuk Yee 
Published: June 2010

AbstractA new strategy was developed for the synthesis of a valuable class of α‐aminomethylacrylates via the Baylis–Hillman reaction of different aldehydes with methyl acrylate followed by acetylation of the resulting allylic alcohols and SN2′‐type amination of the allylic acetates. Asymmetric hydrogenation of these diverse olefinic precursors using rhodium(Et‐Duphos) catalysts provided the corresponding β2‐amino acid derivatives with excellent enantioselectivities and exceedingly high reactivities (up to >99.5% ee and S/C=10,000). The first hydrogenation of (Z)‐configurated substrates was studied for the synthesis of β2‐amino acid derivatives. The high influence of the substrate geometry and steric hindrance on the reactivity and enantioselectivity was also disclosed for this reaction. This protocol provides a highly practical, facile and scalable method for the preparation of optically pure β2‐amino acids and their derivatives under mild reaction conditions.
Michael Reaction of Nitroalkanes with β‐Nitroacrylates under a Solid Promoter: Advanced Regio‐ and Diastereoselective Synthesis of Nitro‐Functionalized α,β‐Unsaturated Esters and 1,3‐Butadiene‐2‐carboxylates
Authors: Palmieri Alessandro , Gabrielli Serena , Ballini Roberto 
Published: June 2010

AbstractA new class of nitro‐functionalized α,β‐unsaturated esters has been prepared by a regio‐ and diastereoselective Michael addition of nitroalkanes to β‐nitroacrylates, performed at room temperature, under carbonate on polymer as promoter, and in the presence of ethyl acetate as eco‐friendly solvent. Moreover, by the modular choice of the reaction conditions the method allows the synthesis of 1,3‐butadiene‐2‐carboxylates.
Metalloporphyrin/Iodine(III)‐Cocatalyzed Oxygenation of Aromatic Hydrocarbons
Authors: Yoshimura Akira , Neu Heather M. , Nemykin Victor N. , Zhdankin Viktor V. 
Published: June 2010

AbstractHypervalent iodine species have a pronounced catalytic effect on the metalloporphyrin‐mediated oxygenations of aromatic hydrocarbons. In particular, the oxidation of anthracene to anthraquinone with Oxone readily occurs at room temperature in aqueous acetonitrile in the presence of 5–20 mol% of iodobenzene and 5 mol% of a water‐soluble iron(III)‐porphyrin complex. 2‐tert‐Butylanthracene and phenanthrene also can be oxygenated under similar conditions in the presence of 50 mol% of iodobenzene. The oxidation of styrene in the presence of 20 mol% of iodobenzene leads to a mixture of products of epoxidation and cleavage of the double bond. Partially hydrogenated aromatic hydrocarbons (e.g., 9,10‐dihydroanthracene, 1,2,3,4‐tetrahydronaphthalene, and 2,3‐dihydro‐1H‐indene) afford under these conditions products of oxidation at the benzylic position in moderate yields. The proposed mechanism for these catalytic oxidations includes two catalytic redox cycles: 1) initial oxidation of iodobenzene with Oxone producing the hydroxy(phenyl)iodonium ion and hydrated iodosylbenzene, and 2) the oxidation of iron(III)‐porphyrin to the oxoiron(IV)‐porphyrin cation‐radical complex by the intermediate iodine(III) species. The oxoiron(IV)‐porphyrin cation‐radical complex acts as the actual oxygenating agent toward aromatic hydrocarbons.
Start‐up transients in a pneumatic foam
Authors: Shaw Ryan , Evans Geoffrey M. , Stevenson Paul 
Published: June 2010

AbstractIn the current work, transient features of initiation in a gas‐liquid pneumatic foam are investigated by measuring the evolution of volumetric liquid fraction as a function of height within the column. The addition of wash water to a flotation froth is only effective when the foam liquid fraction has reached a steady state. This makes start‐up transients in pneumatic foam worthy of study. For the conditions adopted in the experiments, an approximately steady state was achieved after typically 500s, but there was significant fluctuation in liquid fraction after this time. In general, three possible regimes in the start‐up transient (induction, growth and evolution) have been identified and a tentative mathematical model has been described for the last two. However, because it has been demonstrated that the method of obtaining bubble size distributions by analysing images taken through the column wall is deficient, no comparison of these models with the data has been attempted. Copyright © 2010 Curtin University of Technology and John Wiley & Sons, Ltd.
The efficacy and safety of abatacept in patients with non–life‐threatening manifestations of systemic lupus erythematosus: Results of a twelve‐month, multicenter, exploratory, phase IIb, randomized, double‐blind, placebo‐controlled trial
Authors: Merrill J. T. , Burgos‐Vargas R. , Westhovens R. , Chalmers A. , D'Cruz D. , Wallace D. J. , Bae S. C. , Sigal L. , Becker J.‐C. , Kelly S. , Raghupathi K. , Li T. , Peng Y. , Kinaszczuk M. , Nash P. 
Published: June 2010

AbstractObjectiveTo evaluate abatacept therapy in patients with non–life‐threatening systemic lupus erythematosus (SLE) and polyarthritis, discoid lesions, or pleuritis and/or pericarditis.MethodsIn a 12‐month, multicenter, exploratory, phase IIb randomized, double‐blind, placebo‐controlled trial, SLE patients with polyarthritis, discoid lesions, or pleuritis and/or pericarditis were randomized at a ratio of 2:1 to receive abatacept (∼10 mg/kg of body weight) or placebo. Prednisone (30 mg/day or equivalent) was given for 1 month, and then the dosage was tapered. The primary end point was the proportion of patients with new flare (adjudicated) according to a score of A/B on the British Isles Lupus Assessment Group (BILAG) index after the start of the steroid taper.ResultsA total of 118 patients were randomized to receive abatacept and 57 to receive placebo. The baseline characteristics were similar in the 2 groups. The proportion of new BILAG A/B flares over 12 months was 79.7% (95% confidence interval [95% CI] 72.4, 86.9) in the abatacept group and 82.5% (95% CI 72.6, 92.3) in the placebo group (treatment difference −3.5 [95% CI −15.3, 8.3]). Other prespecified flare end points were not met. In post hoc analyses, the proportions of abatacept‐treated and placebo‐treated patients with a BILAG A flare were 40.7% (95% CI 31.8, 49.5) versus 54.4% (95% CI 41.5, 67.3), and the proportions with physician‐assessed flare were 63.6% (95% CI 54.9, 72.2) and 82.5% (95% CI 72.6, 92.3), respectively; treatment differences were greatest in the polyarthritis group. Prespecified exploratory patient‐reported outcomes (Short Form 36 health survey, sleep problems, fatigue) demonstrated a treatment effect with abatacept. The frequency of adverse events (AEs) was comparable in the abatacept and placebo groups (90.9% versus 91.5%), but serious AEs (SAEs) were higher in the abatacept group (19.8 versus 6.8%). Most SAEs were single, disease‐related events occurring during the first 6 months of the study (including the steroid taper period).ConclusionAlthough the primary/secondary end points were not met in this study, improvements in certain exploratory measures suggest some abatacept efficacy in patients with non–life‐threatening manifestations of SLE. The increased rate of SAEs requires further assessment.
Extracellular calreticulin is present in the joints of patients with rheumatoid arthritis and inhibits FasL (CD95L)–mediated apoptosis of T cells
Authors: Tarr Joanna M. , Winyard Paul G. , Ryan Brent , Harries Lorna W. , Haigh Richard , Viner Nick , Eggleton Paul 
Published: June 2010

AbstractObjectiveThe binding of FasL (CD95L) to its receptor, Fas (CD95), induces apoptosis. Studies have shown that in patients with rheumatoid arthritis (RA), T lymphocytes are resistant to FasL‐induced apoptosis in vivo but are susceptible to FasL‐induced apoptosis in vitro. Dysfunction in this mechanism may be an important contributor to the pathophysiology of RA. Thus, the present study was undertaken to determine which factors might inhibit FasL–Fas binding in vivo and those that would inhibit apoptosis of T lymphocytes in an in vitro model system.MethodsHuman Jurkat T cells rendered apoptotic by FasL exposure were analyzed by flow cytometry. Necrosis was determined according to measurement of lactate dehydrogenase release. Quantification of calreticulin in plasma and synovial fluid and of calreticulin–FasL binding was performed by enzyme‐linked immunosorbent assay. Measurement of nitrite/nitrate in the plasma and synovial fluid was carried out by chemiluminescence assay.ResultsExtracellular calreticulin was present at a significantly higher concentration in the plasma (median 10.3 ng/ml, interquartile range [IQR] 14.8 ng/ml) and synovial fluid (median 10.3 ng/ml, IQR 12.0 ng/ml) of RA patients (each P < 0.05) compared with the plasma (median 3.1 ng/ml, IQR 1.3 ng/ml) and synovial fluid (median 2.9 ng/ml, IQR 0.9 ng/ml) of patients with psoriatic arthritis and the plasma of healthy control subjects (median 2.9 ng/ml, IQR 0.9 ng/ml). Calreticulin concentrations in the synovial fluid correlated with the tender and swollen joint counts and the activity scores on the 28‐joint Disease Activity Score assessment. Calreticulin also bound directly to FasL. In vitro, calreticulin (2–16 ng/ml) inhibited FasL‐induced apoptosis of Jurkat T cells.ConclusionCalreticulin was present at higher concentrations in the plasma and synovial fluid of RA patients. Calreticulin had the capacity to bind directly to FasL and to inhibit FasL‐mediated apoptosis of Jurkat T cells, and thus might play a role in inhibiting apoptosis of inflammatory T cells in RA.
Comparison of visual sensitivity to human and object motion in autism spectrum disorder
Authors: Kaiser Martha D. , Delmolino Lara , Tanaka James W. , Shiffrar Maggie 
Published: June 2010

AbstractSuccessful social behavior requires the accurate detection of other people's movements. Consistent with this, typical observers demonstrate enhanced visual sensitivity to human movement relative to equally complex, nonhuman movement [e.g., Pinto & Shiffrar, 2009]. A psychophysical study investigated visual sensitivity to human motion relative to object motion in observers with autism spectrum disorder (ASD). Participants viewed point‐light depictions of a moving person and, for comparison, a moving tractor and discriminated between coherent and scrambled versions of these stimuli in unmasked and masked displays. There were three groups of participants: young adults with ASD, typically developing young adults, and typically developing children. Across masking conditions, typical observers showed enhanced visual sensitivity to human movement while observers in the ASD group did not. Because the human body is an inherently social stimulus, this result is consistent with social brain theories [e.g., Pelphrey & Carter, 2008; Schultz, 2005] and suggests that the visual systems of individuals with ASD may not be tuned for the detection of socially relevant information such as the presence of another person. Reduced visual sensitivity to human movements could compromise important social behaviors including, for example, gesture comprehension.
Vertikale Schwingungen von Blockfundamenten bei linearer Dichtezunahme des Baugrunds
Authors: Scheiter Siegfried 
Published: June 2010

AbstractAuf einem Sandvorkommen werden sechs Blockfundamente zu stationären Schwingungen angeregt. Die Scherwellengeschwindigkeit im Baugrund nimmt linear mit der Tiefe zu. Das Schwingungssystem wird durch ein Modell aus einer Feder, Masse und Dämpfung nachgebildet, dessen Elemente frequenzunabhängig sind. Für die wirksame Baugrundtiefe ist die doppelte Kantenlänge des Fundaments repräsentativ. Im Resonanzfall ist die Länge der abgestrahlten Wellen unabhängig von der Scherwellengeschwindigkeit. Sie vergrößert sich linear mit der Kantenlänge und der Quadratwurzel aus dem Quotient der am Schwingungsvorgang beteiligten Gesamtmasse und der Feder.Vertical vibrations of block foundations with linear increase in density of the soil. On a sand stratum six block foundations are activated to stationary oscillations. The shear wave velocity in the soil increases linearly with depth. The oscillating system is replicated by a model of a spring, mass and damping, whose elements are frequency independent. The effective soil depth is represented by the double edge length of the foundation. In the case of resonance, the length of the radiated waves is independent of the shear wave velocity. It increases linearly with the edge length and the square root of the ratio of the total mass, involved in the oscillation process, and of the spring.
Empfehlung Nr. 5 “Punktlastversuche an Gesteinsproben“ des Arbeitskreises 3.3 “Versuchstechnik Fels“ der Deutschen Gesellschaft für Geotechnik
Authors: Thuro Kurosch 
Published: June 2010

AbstractDer Arbeitskreis AK 3.3 “Versuchstechnik Fels“ der Deutschen Gesellschaft für Geotechnik e. V. erarbeitet Empfehlungen für felsmechanische Labor‐ und Feldversuche sowie Messungen im Gebirge und an Bauwerken. Die vorliegende Neufassung der Empfehlung Nr. 5 behandelt den Punktlastversuch an Gesteinsprobekörpern und berücksichtigt die Weiterentwicklung der Versuchstechnik und ‐auswertung seit der gleichnamigen Empfehlung Nr. 5 von 1982. Es werden die Anforderungen an die Prüfeinrichtung und die Probekörper sowie die Vorgehensweisen für die Durchführung und Auswertung von Punktlastversuchen festgelegt. Die wesentliche Neuerung besteht darin, dass nicht mehr der Lastpunktabstand allein, sondern die Probekörperfläche zur Berechnung des Punktlastindex verwendet wird.Beim Punktlastversuch wird ein Indexwert für die Festigkeit eines Gesteins bestimmt, indem ein zylinderförmiger, quaderförmiger oder unregelmäßig geformter Probekörper zwischen zwei Lasteinleitungsspitzen bis zum Bruch belastet wird. In dieser Empfehlung werden der Zweck, die Begriffe, die Prüfeinrichtung, die Anforderungen an den Probekörper und die Versuchsdurchführung erläutert. Drei mögliche Optionen der Versuchsauswertung werden aufgezeigt, die Darstellung der Ergebnisse beschrieben und mit Hilfe von Beispielen illustriert. Abschließend wird erläutert, wie die einaxiale Druckfestigkeit aus der Punktlastfestigkeit abgeleitet werden kann.Recommendation No. 5 (revised) of the Commission on Rock Testing of the Deutsche Gesellschaft für Geotechnik e.V. — “point load tests on rock samples”. The Commission on Rock Testing of the Deutsche Gesellschaft für Geotechnik e.V. (German Geotechnical Society) is compiling instructions for rock tests conducted in the laboratory and in‐situ, and for performing monitoring of rock masses and civil engineering structures. The revised version of recommendation No. 5 deals with the point load test on rock samples and incorporates recent developments in testing machines and testing procedures since the first version from 1982. The requirements for the testing machines and the specimens are given, as well as the procedures to perform the tests and evaluate the data. The essential modification is the use of the sample area instead of the platen tip distance alone.The point load test is used to derive an index value for rock strength. Therefore rock specimens in the form of core, cut blocks or irregular lumps are loaded until failure between a pair of load tips. In this recommendation, scope, terms, apparatus, specimen requirements and procedure of the test are explained. Three possible options of test evaluation are given, the reporting of results described and illustrated by examples. Finally it is shown, how the uniaxial compressive strength can be derived by the point load strength.