bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bauschinger effect in thin metal films simulated by the continuum dislocation-based model
Authors: Sedláček Radan , Schwarz Cornelia , Wesenjak Robert , Bensimon Adrien 
Published: March 2009

Abstract
The continuum dislocation-based model is applied to cyclic deformation of thin constrained crystalline strips. The simulated size effect upon loading as well as the size-dependent Bauschinger effect upon unloading are caused by the line tension of the curved dislocations that bow out between the impenetrable edges of the strip.
Alloying behaviour of binary transition metal systems
Authors: Paidar Václav , Duparc Olivier Hardouin 
Published: March 2009

Abstract
The properties of A – B binary alloys are controlled by the mixed AB interaction potentials. The interfaces between two different metals are investigated for fictive mixed potentials spreading from A-type to B-type nature. The elemental AA and BB potentials are fixed. The tendencies towards formation of ordered structures on one side, and separation of phases on the other side are discussed. A description of interatomic forces respecting metallic bonding character in many-body potentials is used. This approach can be helpful for applications of alloy potentials in models with complex structures of extended defects such as dislocations and grain boundaries and in the assessment of their behaviour.
Surface composition of a Ag-5.1Cu (mass%) alloy
Authors: Vaníčková Jaroslava , Kovač Janez , Děd Jirí , Lejček Pavel , Samardžija Zoran , Zalar Anton 
Published: March 2009

Abstract
X-ray photoelectron spectroscopy was applied to study the evolution of surface composition in a polycrystalline Ag-5.1Cu mass% alloy during in-situ annealing in ultra-high vacuum at temperatures ranging between 300 °C and 600 °C. The results show an enrichment of copper on the free surface. The results imply that the compositional changes at the surface of this alloy are dominated by copper segregation at grain boundaries.
Quantitative characterization of the orientation spread within individual grains in copper after tensile deformation
Authors: Krog-Pedersen Stine , Bowen Jacob R. , Pantleon Wolfgang 
Published: March 2009

Abstract
By means of electron backscatter diffraction, orientations are determined on a regular grid on a polished section of a copper specimen after tensile deformation to 25 %. Individual grains separated by boundaries with disorientation angles above 7 are identified and the microtexture in the form of the orientation distribution function of each individual grain is analyzed. Extent and shape of the disorientation distribution in orientation space are quantified by the tensor of the second-order central moments, its principal values and directions. The latter characterize the main rotation axes of the orientation spread and the former the extent of the distribution in orientation space along these principal axes allowing a classification of the disorientation distribution into archetypical shapes. The disorientation distributions developed in grains with tensile axes close to [001] or [011] are more anisotropic than expected from their eight possibly activated slip systems indicating a mutual suppression of possibly activated slip systems.
Comparative study of the high-temperature behaviour of Mg–Al and Mg–Zn wrought alloys
Authors: Mehtedi Mohamad El , Spigarelli Stefano , Evangelista Enrico , Rosen Gady 
Published: March 2009

Abstract
The high-temperature workability of AZ31 has been extensively investigated in recent years, since this alloy is considered the best candidate for production of wrought components in Mg. While peak flow stresses, and thus working loads during rolling, extrusion or forging, seem to weakly depend on the initial microstructure, the same conclusion does not hold for the ductility of the alloy. Fewer studies have considered the high temperature workability of Mg – Zn alloys. This study aims at relating the mechanical response of the materials, in term of flow stresses and strain to fracture, with the chemical composition and the prior microstructure. The results of mechanical testing in torsion, carried out in the same regime of temperature and strain rates were then analysed and discussed. Constitutive equations relating flow stresses to straining conditions were obtained for each tested alloy, and the differences in strain-to-fracture were closely analysed.
Influence of the dynamic crystallization conditions on the martensitic transformation in the Ti40.7Hf9.5Ni39.8Cu10 shape memory alloy
Authors: Resnina Natalia , Belyaev Sergey , Shelyakov Alexander 
Published: March 2009

Abstract
The article deals with the problem of the influence of the dynamic crystallization conditions on the structure and on the martensitic transformation in amorphous Ti40.7 Hf9.5 Ni39.8 Cu10 thin ribbons. The crystallization was realized in a DSC apparatus by heating the samples at different heating rates. DSC and X-ray diffraction were employed to study the martensitic transformation and the structure of the crystallized ribbons. The data show that increasing heat rate resulted in an increase in the crystallization temperature, a decrease in the B2 ↔ B19′ transformation temperature and an extension of the halfwidth of (110) reflections of the B2 phase. It is concluded that the increase in the heating rate decreases the grain size of the crystalline phase. As the temperature of the B2 ↔ B19′ transition depends sensitively on the grain size the heating rate could be used for controlling the characteristics of the phase transformations.
Very high cycle fatigue behaviour of as-extruded AZ31, AZ80, and ZK60 magnesium alloys
Authors: Nový František , Janeček Miloš , Škorík Viktor , Müller Julia , Wagner Lothar 
Published: March 2009

Abstract
The very high cycle fatigue properties of extruded AZ31, AZ80, and ZK60 magnesium alloys were investigated. Fatigue tests were performed at ultrasonic cyclic frequency and at a load ratio of R = – 1 at ambient temperature using smooth electropolished specimens. Fatigue failures were observed at lifetimes above 109 cycles. The fatigue life was found to increase with decreasing stress amplitude. The fracture surfaces and fracture profiles of selected specimens cycled until failure were examined. The purpose of the study was to determine the role of the microstructure on the fatigue crack nucleation and growth. Furthermore, the fatigue properties were discussed on the basis of microstructure and the presence of inclusions which are known as crack initiation sites. In AZ31 and AZ80 alloys only surface-induced fatigue cracks were observed. On the other hand, in the ZK60 alloy both surface- and interior-induced fatigue cracks were observed. Both mechanisms operate in the ZK60 also at a lifetime of around 1010 cycles. Interior-induced fatigue cracks were accompanied by clear fish-eye marks on the fracture surfaces of the ZK60 alloy.
Isostructural phase transition in hexagonal Ce1–x
Y
x
PdAl compounds
Authors: Rusňák Martin , Prchal Jiří , Daniš Stanislav 
Published: March 2009

Abstract
The Ce1 – x
Y
x
PdAl pseudoternaries belong to the ternary RTX compounds (where R stands for rare-earth, T for transition metal, X for a p-metal). We have studied three compounds with compositions x = 0.2, 0.5, and 0.8 by means of X-ray diffraction at room temperature. Moreover, Ce0.5 Y0.5 PdAl was also studied in the temperature range from 70 K to 500 K. The existence of a gap of forbidden values of the c/a ratio was confirmed. The compounds with x = 0.2 and 0.8 have different phases. The compound with x = 0.5 exhibits coexistence of both the x = 0.2 and x = 0.8 phases. The diffraction patterns and the calculated lattice parameters indicate that the Ce0.5 Y0.5 PdAl sample undergoes a phase transition towards the single-phased state at both high and low temperatures.
Temperature and strain rate dependent flow criterion for bcc transition metals based on atomistic analysis of dislocation glide
Authors: Gröger Roman , Vitek Vaclav 
Published: March 2009

Abstract1/2111 screw dislocations that possess non-planar cores and thus a high lattice friction (Peierls) stress control the plastic deformation of pure bcc metals. In this paper we formulate an analytical flow criterion based on the recognition that at finite temperatures the screw dislocations glide via formation and subsequent propagation of pairs of kinks. This development employs first an atomistically calculated dependence of the Peierls stress on the applied loading to construct the Peierls potential that depends on the applied stress tensor. This Peierls potential is then used to evaluate the activation enthalpy for the kink-pair formation employing mesoscopic dislocation models and its dependence on the applied stress tensor is then approximated by a relatively simple analytical form. Using the standard transition state theory to ascertain the dislocation velocity and related strain rate allows us to formulate the temperature and strain rate dependent flow criterion. Implications of this criterion are then compared with available experimental data demonstrating its excellent predictive value.
Deformation behaviour of microcrystalline magnesium reinforced by alumina nano- and microparticles
Authors: Drozd Zdeněk , Trojanová Zuzanka 
Published: March 2009

Abstract
Mg-based micro- and nanocomposites were prepared by the powder metallurgical route. Specimens were deformed in tension and in compression at temperatures between RT and 300 °C at a constant crosshead speed giving an initial strain rate of 5.5 × 10– 5 s– 1. Both a yield stress and an ultimate stress improvement were observed in the composites in comparison with the unreinforced microcrystalline Mg. A different deformation behaviour in tension and in compression was observed. The changes in the deformation behaviour can be attributed, among others, to twinning, which occurs in the composites at higher stages of deformation. Various contributions to the composite strengthening are discussed.
Long-range internal stresses in monotonically and cyclically deformed metallic single crystals
Authors: Kassner M. E. , Geantil P. , Levine L. E. , Larson B. C. 
Published: March 2009

Abstract
Selected experimental measurements and theoretical predictions for the magnitude of long-range internal stress in monotonically and cyclically deformed metals are assessed and recently developed, spatially-resolved X-ray micro-beam techniques for direct measurements of long-range internal stress are discussed. The results of previously reported differential-aperture X-ray microscopy spatially-resolved measurements of long-range internal stress in dislocation-cell interiors in monotonically deformed copper are compared with predictions and analyses associated with the composite model of deformation. In addition, the results of volume-integrating X-ray line-profile measurements and spatially-resolved differential-aperture X-ray microscopy measurements of strains in <100> oriented copper single crystals that were cyclically deformed to pre-saturation (without persistent slip bands) are presented.
High-rate plastic deformation of a copper single crystal under loading by spherical converging shock waves
Authors: Dobromyslov Arkadiy , Taluts Nina , Kozlov Evgeniy 
Published: March 2009

Abstract
A copper single crystal was deformed by spherical converging shock waves. The structure of the recovered specimen was studied by X-ray diffraction analysis (including back-reflection Laue technique), optical and transmission electron microscopy as well as by the measurement of microhardness along the radius in some radial directions. It is established that the high-rate plastic deformation of a copper single crystal under such loading proceeds mainly by both crystallographic and non-crystallographic slip.
Fe–Al materials for structural applications at high temperatures: Current research at MPIE
Authors: Palm Martin 
Published: March 2009

Abstract
Fe – Al-based materials possess a number of properties which make them highly interesting for the development of new light-weight structural materials. However, lack of strength at high temperatures and limited ductility at ambient temperatures so far has hindered any wider application of these materials. Recent progress achieved within an inter-departmental research initiative at the Max-Planck-Institut für Eisenforschung GmbH is reviewed here. Based on a sound knowledge of physical and thermodynamic properties and careful analysis of the phase equilibria, various alloy systems have been investigated which offer different mechanisms for strengthening Fe – Al-based materials at high temperatures. By applying these mechanisms Fe – Al-based alloys with sufficient strength for structural applications at least between 650 – 800 °C have been developed. For these alloys processing routes such as rolling and forging have been demonstrated. Low ductility is still a crucial issue, but measures exist for improving ductility, e. g. by refining the microstructure through thermo-mechanical treatment. It has also been shown that iron aluminides not only show superior corrosion resistance in oxidising and sulphidising atmospheres but also in other hostile environments like carburising atmospheres and under molten salts.
Enhanced estimation of glacier mass balance in unsampled areas by means of topographic data
Authors: Carturan Luca , Cazorzi Federico , Dalla Fontana Giancarlo 
Published: March 2009

AbstractA new method was developed to estimate the mass balance in unsampled areas from existing datasets. Three years of mass-balance data from two glaciers in the central Italian Alps were used to develop and test a multiple-regression method based exclusively on a 10m resolution digital terrain model. The introduction of a relative elevation attribute, which expresses the degree of wind exposure of the gridcells, notably increased the amount of explainable variance in winter balance with respect to altitude itself. The summer balance is highly correlated with elevation, but, in order to obtain reliable extrapolations, the clear-sky shortwave radiation and the diurnal cloud-cover cycle had to be taken into account. The net annual mass balance on a glacier system comprising the two monitored glaciers was calculated by applying both a single regression of winter and summer balance with altitude and the new regression method. The consistency of results was assessed against measured net balances and snow-cover maps drawn in the ablation season. The results of the new method were in close agreement with observations and proved to be less sensitive to the spatial representation of the sampled areas.
Geodetic mass balance of the western Svartisen ice cap, Norway, in the periods 1968–1985 and 1985–2002
Authors: Haug Torborg , Rolstad Cecilie , Elvehøy Hallgeir , Jackson Miriam , Maalen-Johansen Ivar 
Published: March 2009

AbstractThe geodetic mass balance of the western Svartisen ice cap in northern Norway is determined, in this work, from photogrammetry on vertical aerial photographs taken in 1968, 1985 and 2002. The existing 1968 digital terrain model (DTM) was generated using analogue photogrammetry, and the 1985 and 2002 DTMs are newly generated using digital photogrammetry. The geodetic mass balance for 1968–85 is –2.6±0.8mw.e., and for 1985–2002 it is –2.0±1.6mw.e. The area of western Svartisen decreased from 190 km2 in 1968, to 187 km2 in 1985 and to 184 km2 in 2002. The outlet glacier Flatisen in the southeast retreated 1700 m over the two periods. The geodetic mass balance is also determined for Engabreen drainage basin, as –2.1±0.9mw.e. for the first period, and –0.3±2.4mw.e. for the second. The results for Engabreen are compared to traditional mass balances, and the large deviations cannot be explained from uncertainties determined for the geodetic method. The assessed errors contributing to the uncertainty in the geodetic mass balance are elevation errors, uncertainties from the applied melt correction, and the use of Sorge’s law, assuming constant snow thickness and density.
After six decades of monitoring glacier mass balance we still need data but it should be richer data
Authors: Braithwaite Roger J. 
Published: March 2009

AbstractThis paper reviews data on glacier mass balance together with extra metadata on topography and climate to put the data into context. The 2007 Intergovernmental Panel on Climate Change (IPCC) estimates of global average glacier mass balance may not be much different from simple averages. A more mathematically correct approach is to analyse long and continuous mass-balance series measured in different regions, but there are few long series and they do not cover the globe in any representative way. However, 30 year series from 30 glaciers confirm a recent (1996–2005) trend to very negative mass balance after two decades of nearly zero mass balance. Climate data from a global gridded climatology are applied to datasets for global glacier cover, for 318 glaciers with mass-balance data for at least 1 year and for 30 glaciers with 30 year series of measurements. Results show that mean precipitation is relatively low in the global glacier-cover dataset and much higher for the observed glaciers. This shows that current mass-balance measurements are biased towards wetter conditions than are typical for global glacier cover. We urgently need to find better ways of analysing sparse datasets with ‘complex spatial and temporal patterns’ like the present mass-balance dataset.
Six decades of glacier mass-balance observations: a review of the worldwide monitoring network
Authors: Zemp M. , Hoelzle M. , Haeberli W. 
Published: March 2009

AbstractGlacier mass balance is the direct and undelayed response to atmospheric conditions and hence is among the essential variables required for climate system monitoring. It has been recognized as the largest non-steric contributor to the present rise in sea level. Six decades of annual mass-balance data have been compiled and made easily available by the World Glacier Monitoring Service and its predecessor organizations. In total, there have been 3480 annual mass-balance measurements reported from 228 glaciers around the globe. However, the present dataset is strongly biased towards the Northern Hemisphere and Europe and there are only 30 ‘reference’ glaciers that have uninterrupted series going back to 1976. The available data from the six decades indicate a strong ice loss as early as the 1940s and 1950s followed by a moderate mass loss until the end of the 1970s and a subsequent acceleration that has lasted until now, culminating in a mean overall ice loss of over 20mw.e. for the period 1946–2006. In view of the discrepancy between the relevance of glacier mass-balance data and the shortcomings of the available dataset it is strongly recommended to: (1) continue the long-term measurements; (2) resume interrupted long-term data series; (3) replace vanishing glaciers by early-starting replacement observations; (4) extend the monitoring network to strategically important regions; (5) validate, calibrate and accordingly flag field measurements with geodetic methods; and (6) make systematic use of remote sensing and geo-informatics for assessment of the representativeness of the available data series for their entire mountain range and for the extrapolation to regions without in situ observations; and (7) make all these data and related meta-information available.
Surface mass-balance changes of the Greenland ice sheetc since 1866
Authors: Wake L.M. , Huybrechts P. , Box J.E. , Hanna E. , Janssens I. , Milne G.A. 
Published: March 2009

AbstractMass loss from the Greenland ice sheet over the past decade has caused the impression that the ice sheet has been behaving anomalously to the warming of the 1990s. We have reconstructed the recent (1866–2005) surface mass-balance (SMB) history of the Greenland ice sheet on a 5 × 5 km grid using a runoff-retention model based on the positive degree-day method. The model is forced with new datasets of temperature and precipitation patterns dating back to 1866.We use an innovative method to account for the influence of year-on-year surface elevation changes on SMB estimates and have found this effect to be minor. All SMB estimates are made relative to the 1961–90 average SMB and we compare annual SMB estimates from the period 1995–2005 to a similar period in the past (1923–33) where SMB was comparable, and conclude that the present-day changes are not exceptional within the last 140 years. Peripheral thinning has dominated the SMB response during the past decade, as in 1923–33, but we also show that thinning was not restricted to the margins during this earlier period.
Implications for the dynamic health of a glacier from comparison of conventional and reference-surface balances
Authors: Harrison W.D. , Cox L.H , Hock R. , March R.S. , Pettit E.C. 
Published: March 2009

AbstractConventional and reference-surface mass-balance data from Gulkana and Wolverine Glaciers, Alaska, USA, are used to address the questions of how rapidly these glaciers are adjusting (or ‘responding’) to climate, whether their responses are stable, and whether the glaciers are likely to survive in today’s climate. Instability means that a glacier will eventually vanish, or at least become greatly reduced in volume, if the climate stabilizes at its present state. A simple non-linear theory of response is presented for the analysis. The response of Gulkana Glacier is characterized by a timescale of several decades, but its stability and therefore its survival in today’s climate are uncertain. Wolverine seems to be responding to climate more slowly, on the timescale of one to several centuries. Its stability is also uncertain, but a slower response time would make it more susceptible to climate changes.
Ground-based gravimetry for measuring small spatial-scale mass changes on glaciers
Authors: Breili Kristian , Rolstad Cecilie 
Published: March 2009

AbstractGravity change on a glacier surface is a composite of several effects (e.g. melting and accumulation of snow and ice, redistribution of mass with depth by refreezing of meltwater and height and thickness changes of the snow and ice layers). Models and equations necessary to estimate the measured gravity change due to different effects are presented, and the propagation of observational errors is evaluated. The paper presents experiences with ground-based gravity measurements carried out on Hardangerjøkulen, Norway, in spring and autumn 2007. It was found that the vertical gradient of gravity contributes most to the uncertainty in the determined mass change. With present instrumentation, gravity can be measured with the required accuracy to determine the mass loss to ∼10% of the loss determined by conventional mass-balance measurements. Improvements in field procedures to achieve the required accuracy for measuring the mass/density changes directly, combining gravity measurements and GNSS (Global Navigation Satellite Systems), are discussed.
Glacier changes in Alaska: can mass-balance models explain GRACE mascon trends?
Authors: Arendt Anthony A. , Luthcke Scott B. , Hock Regine 
Published: March 2009

AbstractTemperature and precipitation data from three weather stations in the St Elias Mountains of Alaska and northwestern Canada were used to drive one-dimensional (1-D) (elevation-dependent) and 0-D degree-day mass-balance models. Model outputs were optimized against a 10 day resolution time series of mass variability during 2003–07 obtained from Gravity Recovery and Climate Experiment (GRACE) mass concentration (mascon) solutions. The models explained 52–60% of the variance in the GRACE time series. Modelled mass variations matched the phase of the GRACE observations, and all optimized model parameters were within the range of values determined from conventional mass-balance and meteorological observations. We describe a framework for selecting appropriate weather stations and mass-balance models to represent glacier variations of large regions. There is potential for extending these calibrated mass-balance models forwards or backwards in time to construct mass-balance time series outside of the GRACE measurement window.