bluuebunny/crossref_metadata_2025_split huggingface dataset:
Neutron Texture Investigations on Natural Mt. Isa Chalcopyrite Ore – Part II: Preferred Orientation of Chalcopyrite After Different Experimental Deformation Conditions
Authors: Jansen E. M. , Brokmeier H.-G. , Siemes H. 
Published: April 2008

Natural chalcopyrite samples from Mt. Isa, Australia were axially shortened at a constant confining
pressure of 300 (400) MPa, at different temperatures from 25–450°C, in the strain rate range of
3 · 10−5 − 6 · 10−8sec−1. Neutron diffraction texture analyses of all deformed samples were carried out and compared to the preferred orientation before the experimental deformation.The preferred orientation of the experimentally undeformed samples consists of three main orientation components, which become weaker with deformation at temperatures to 200°C. One or two new components (A, B) develop with the c‐axes perpendicular to the principal strain direction. At a deformation temperature of 250°C and to slower strain rates at 200°C the relics of the original components are stronger. After deformation at temperatures of 300°C to 450°C in general two different types of preferred orientation were detected. One type (2NF) shows two different new components (A*, C), the original components are completely dissolved. The other type (IN) shows the original components partially more concentrated, especially to slower strain rates, and shifting into the directions of the new components of the type 2NF.
Effect of the Grain Shape on the Elastic Constants of Polycrystalline Materials
Authors: Kiewel H. , Bunge H. J. , Fritsche L. 
Published: April 2008

We examine the influence of the grain shape on the effective elastic moduli of polycrystalline materials. For that purpose the real material is simulated by a cluster of Wigner‐Seitz cells. For clarity each aggregate consists of grains with only one type of shape. Therefore we can classify each cluster by the coordination number of its grains. To determine the elastic moduli a homogeneous deformation is subjected to the surface of the cluster. The solution of this boundary value problem yields the average stress and strain governing inside the material whose interconnection by Hooke′s law leads to the sought‐for effective constants.The most important result is that with increasing coordination number the elastic moduli decrease.
Influence of Texture on Powder Diffraction
Authors: Bunge H. J. 
Published: April 2008

Classical Powder Diffraction usually assumes samples with
completely random orientation distribution of the crystallites. It
can be generalized to non‐random orientation distribution
(texture) by introducing a texture factor which enters the
expression of the integral intensity directly and serves as a
weight function in expressions of peak shift or peak broadening.
Hence, all methods of powder diffraction, for instance, phase
analysis, crystal structure analysis, stress analysis, particles
size analysis, can also be carried out with textured samples.Textured polycrystalline samples may be considered as being
intermediate between single crystals and random powder samples.
Hence, they contain information about the directions of reciprocal
lattice vectors which are “averaged out” in random polycrystals,
the measured intensities of which depend only on the absolute
values . This information can be used, for instance, to separate overlapped structure factors or to index powder diffraction diagrams.
High Temperature Texture Goniometer for in Situ Measurements of Transformation Textures
Authors: Brückner G. , Reher F. R. , Gottstein G. 
Published: April 2008

A high temperature stage was designed for mounting onto a computer controlled four
circle X‐ray texture goniometer. This technique allowed to conduct in situ texture measurement,
i.e. the determination of the texture evolution during rather than subsequent to
annealing. The device was employed for temperatures up to 1000°C.The furnace consisted of a resistance wire of Pt30Rh, which was isolated against the
specimen with Al2O3 glue. The furnace with the specimen was covered by a hemispherical
KaptonTM foil. Inside the hemisphere a reducing gas atmosphere was used to avoid
oxidation of the sample surface.
New Possibilities of Phase, Texture, and Stress Analysis Using Energy Dispersive Detectors
Authors: Moras K. , Arnhold R. 
Published: April 2008

For angular dispersive and energy dispersive phase, texture, and stress analysis of compact samples (TiAl) and thin TiN layers, an electroluminescence detector and a Si(Li) semiconductor detector were applied. The parameters and application properties of the detectors are described. For angular dispersive measurements higher reflection intensities and better peak‐to‐background ratios can be attained, in comparison to conventional methods, by using multichannel pulse accumulation and mathematical spectrum evaluation.In energy dispersive texture and stress measurements, reflection data from several lattice planes can be obtained simultaneously. In stress measurement, variations of lattice spacings in the order of 10-3 are reliably detectable. In principle, texture and stress
information can be received from one measurement.
Comments to a Publication of T.I. Savyolova Concerning Domains of Dependence in Pole Figures
Authors: Matthies S. , Esling C. 
Published: April 2008

A questionable publication of T.I. Savyolova is analysed. The paper claims, that it is possible to determine Ph(y) pole figure values for y ∈ Y(h; h0, Y0) using only data from y ∈ Y0 of a single pole figure . The contradiction to the common knowledge can be resolved well understanding that there is a general difference between the term solutions
(or continuation of solutions) of an ultrahyperbolic equation (satisfied by the axis distribution function A(h, y)) and the term pole figure. Pole figures considered in texture analysis are two‐dimensional projections of a three‐dimensional object (the ODF f(g)). For limited data sets the equation ΔhA(h, y) = ΔyA(h, y) bears only a necessary, but not sufficient character in order to get solutions of interest, i.e. it cannot be guaranteed that a h‐specific continuation of a starting solution will be a “h‐projection” of the same ODF, which belongs to a concrete sample and possesses the “h0‐projection” .Consequently, to name such a h‐specific continuation “pole figure” is incorrect. The consideration of formal (unambiguous only by artificial conditions) continuations of solutions may be mathematically interesting, but is of no practical importance for texture analysis. Examples (already considered by the authors about twenty years ago) are given, how to construct in a much more simple way continuations of solutions of the same useless type like in the paper under discussion.
Oxidation of Zirconium Alloys. Crystallographic Texture of Zirconia: Interpretation and Mechanical Consequences
Authors: Parise M. , Touet I. , Sicardy O. 
Published: April 2008

In order to have a better knowledge of the mechanical behaviour of the oxide layers growing on zirconium alloys in pressurized water reactors, the textures of different zirconium alloys and their oxide layers are studied. The results show that the texture of the oxide layers present a feature common to all the layers: the tilt angle of the maximum intensities of the pole figures obtained on the layers is almost quite identical for all the studied substrates. The azimuthal reinforcements depend on the metallurgical state of the substrate.The crystallographic direction of monoclinic zirconia common to all the oxide grains is identified. A computation based on mechanical issues is presented: considering the anisotropic elastic properties of the monoclinic monocrystal, it is shown that the particular crystallographic direction is linked to an isotropic state of strains in the plane of the metal–oxide interface.
A Simulation of Recrystallization Textures of Al‐Alloys WithConsideration of the Probabilities of Nucleation and Growth
Authors: Engler O. 
Published: April 2008

The characteristic recrystallization texture components of cold rolled Al‐alloys can be
traced back to a growth selection of grains with an approximate 40º 〈111〉
orientation
relationship out of a limited spectrum of preferentially formed nucleus orientations.
Accordingly, recrystallization textures can be modeled by the multiplication of a function
f(g)nucl describing the probability of nucleation of the various orientations and a function
f(g)grow representing their growth probability.Whereas the growth probability can be accounted for by a 40 111 transformation of the
rolling texture, the nucleation probability of the respective grains is given by the distribution
of potential nucleus orientations, which is known from local texture analysis for the most
important nucleation sites in cold rolled Al‐alloys, cube‐bands, grain boundaries and
second‐phase particles. If several nucleation sites are active simultaneously, the nucleation
probabilities have to be weighted according to their respective proportions. For that purpose,
the numbers of nuclei forming at the various nucleation sites were calculated according
to a model approach proposed by Vatne et al. (Acta Mater 44, 1996, 4463–4473).The paper describes the model for recrystallization texture simulation in Al‐alloys and
gives examples of recrystallization textures simulated regarding a variation of different
microstructural parameters to demonstrate the predictive power of the model.
Influence of the Texture on the Al–6%Mg Alloy Deformation
Authors: Lychagina T. A. , Nikolayev D. I. 
Published: April 2008

The influence of the texture on material mechanical properties and deformation behaviour was widely discussed. (refer to Bunge, H.J. (1982). Texture Analysis in Materials Science Mathematical Methods). Butterworths, London. In this work elastic properties (Young′s modulus) of cold rolled Al–6%Mg alloy sheet were estimated taking into account lattice preferred orientations, which can be described by the orientation distribution function (ODF). The ODF was reconstructed from pole figures measured by means of neutron diffraction and was approximated by normal distributions (Savyolova, T.I. (1994)Zavodskaya Laboratoria 50, N5, 48–52). The method used for calculation is able to express explicitly the polycrystalline elastic property via the single crystal property and the texture parameters.Stress–strain dependenc (deformation curves) was measured by means of uniaxial tensile tests for Al–6%Mg alloy samples with different tensile axis directions. Samples for uniaxial tests were cut at different angles to the rolling direction. The conformity between experimental and computed results is discussed.
Advances in Neutron Diffraction for Engineering Residual Stress Measurements
Authors: Ezeilo A. N. , Webster G. A. 
Published: April 2008

The increasing awareness amongst engineers and designers, of the significance of residual stresses in influencing the useful lifetimes of engineering components, has resulted in more demanding expectations being placed on the methods used to obtain these stresses. The neutron diffraction technique is emerging as the most attractive measuring method as the residual stresses can usually be obtained non‐destructively to depths of up to 40 mm in some common engineering materials. Although it is a relatively new technique it has been used to measure the residual stresses in a range of engineering materials introduced by a wide variety of manufacturing processes such as welding, quenching, machining, shot peening, cold hole expansion and autofrettage.In this paper the neutron diffraction technique for non‐destructive residual stress measurements will be described including methods used to validate the measurements. Precautions that should be taken in order to obtain reliable measurements are outlined. Procedures being investigated in order to produce a code of practice will be presented.
A representative selection of stress distributions developed by a range of manufacturing processes is examined. Some comparisons are made with strain gauge, X‐ray and numerical predictions. It is shown how the results can be of benefit in engineering stress analysis.
Optimization of Texture Measurements—Part I: Method: Optimal GridParameter
Authors: Luzin V. 
Published: April 2008

In texture experiments one always measures a sample with some constrained number of grains N (see the discussion in Bunge (1996). Proc. of Workshop ‘Math. Methods of Texture Analysis’, Textures and Microstructures 25, 71–108). It is clear that the orientation distribution function (ODF) and pole figures (PFs) measured for this limited N may differ from actual ones. How well do texture measurements reproduce the actual distribution densities? The statistical relevance of such measurements is the main area of interest in the present paper.In this article the RP‐value is adopted as the value quantitatively characterizing this relevance. From this point of view the problem of evaluation of true distribution densities means the minimization of the RP‐value over some variables. For evaluation of the pole density (for some PF), we consider the parameter of the measurement grid as the variable of the minimization problem. The number of grains N and the sharpness of the texture are the additional parameters of the problem.Two approaches to solve the mentioned problem are proposed. One is the numerical simulation of the given distribution as the normal (Gaussian) distribution. The other is based on some estimation of the expected RP‐value between the actual and experimental PFs.It turns out that for the given type of the measurement grid (an equidistant grid) the optimal measurement grid parameter exists. This is one that minimizes the RP‐value in dependence on the number of grains N in the sample and sharpness of the texture.
Optimization of Texture Measurements—Part II: Further Applications:Optimal Smoothing
Authors: Luzin V. 
Published: April 2008

In our previous paper (Luzin, 1997. Proc. of Workshop ‘Neutron Textures and Stress Analysis’) the basic principles of the quantitative approach to optimize the texture measurements were outlined. This paper is the report of advances in this direction.The quantitative approach is used to solve the smoothing problem. Smoothing by singular integrals with an integral kernel used by Nikolayev and Ullemeyer (1996). Proc. of Workshop ‘Math. Methods of Texture Analysis’, Textures and Microstructures25, 149– 158 is used in this paper. It is shown how the optimal smoothing parameter depends on the grain statistics, i.e. the number of grains in the sample. The algorithm for optimal smoothing of real pole density data (pole figures) is proposed.Also, the application of optimal smoothing for solving the central problem of quantitative texture analysis (QTA), i.e. orientation distribution function (ODF) reproduction, is discussed.
On the Stress Dependence of Subgrain Size
Authors: Edward G. H. , Etheridge M. A. , Hobbs B. E. 
Published: April 2008

A simple model of the dynamic balance between deformation induced dislocation generation and climb controlled dislocation annihilation in subgrain walls is outlined. This results in a stress‐subgrain size relationship which involves various material properties, including the creep stress exponent and the creep diffusivity.Assuming a fixed slip distance for mobile dislocations, the theory predicts that the subgrain
size (d) depends on the stress (σ) as d4 ∝ σ−n, where n is the creep exponent, and the proportionality constant is dependent on material properties, temperature, and other environmental variables. This theoretical prediction is satisfactorily compared with published experimental results for
a variety of materials.The implications of the environmental dependence of the stress‐subgrain size relation with
regard to its use as a palaeopiezometer in naturally deformed minerals are discussed.
Improvement of Yield Locus Calculation From Pole Figures of Zircaloy Tubes
Authors: Matucha K. H. , Wincierz P. 
Published: April 2008

Improvement of yield locus calculation, i.e. better fit with experimental results, was
achieved for Zircaloy tubes with deformation and recrystallization textures in
the following way: (1) Replacement of information from {}‐ and (0001)‐pole
figures by identification of preferred orientation parallel to the tube axis in
combination with the basal pole density distribution in the plane between radial and
tangential direction as a function of the tilt angle γi. (2) Calculation of those parts of
the yield locus which are independent of mechanical twinning. For uniaxial tensile
stress parallel to the tube axis the slope m of the yield locus line for prismatic glide is
given by mi = cos2γi. (3) Calculation of yield locus parts depending on mechanical
twinning using experimentally well established ratios of critical resolved shear
stresses for prismatic slip and several twinning systems.Mechanical twinning on {}‐planes was confirmed by texture analysis of
plastically deformed tubes after yield locus investigation.
Diurnal refuge-site selection by Brown Treesnakes (Boiga irregularis) on Guam
Authors: Coupe Brad , Anderson Nancy , Hetherington Thomas , Perry Gad , Williams Joseph 
Published: April 2008

AbstractDiurnal refuge-site selection was studied in eleven free-ranging brown tree snakes (Boiga irregularis) in tropical forest on the island of Guam. These nocturnal and mostly arboreal snakes were tracked using implanted radio-transmitters. A vegetation survey of the study site was performed to determine if brown treesnakes non-randomly select certain plants for refuge-sites, and thermal profiles of representative refuge sites were obtained with Hobo data loggers. Brown treesnakes preferentially used Pandanus crowns for refuge-sites. Although Pandanus represents a small proportion (3.6%) of the forest, most snakes used Pandanus most of the time for refuge. The thermal characteristics of Pandanus were comparable to those of other refuge-sites. We speculate that features of Pandanus that provide basking opportunities and moist microhabitats may be important for brown treesnakes. As Pandanus is widely distributed throughout the natural range of the brown treesnake, this genus may represent an important refuge-site for this species.
Hydrometeor Detection Using Cloudsat—An Earth-Orbiting 94-GHz Cloud Radar
Authors: Marchand Roger , Mace Gerald G. , Ackerman Thomas , Stephens Graeme 
Published: April 2008

Abstract
In late April 2006, NASA launched Cloudsat, an earth-observing satellite that uses a near-nadir-pointing millimeter-wavelength radar to probe the vertical structure of clouds and precipitation. The first step in using Cloudsat measurements is to distinguish clouds and other hydrometeors from radar noise. In this article the operational Cloudsat hydrometeor detection algorithm is described, difficulties due to surface clutter are discussed, and several examples from the early mission are shown. A preliminary comparison of the Cloudsat hydrometeor detection algorithm with lidar-based results from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite is also provided.
On Deriving Vertical Air Motions from Cloud Radar Doppler Spectra
Authors: Shupe Matthew D. , Kollias Pavlos , Poellot Michael , Eloranta Edwin 
Published: April 2008

Abstract
A method for deriving vertical air motions from cloud radar Doppler spectrum measurements is introduced. The method is applicable to cloud volumes containing small particles, in this case liquid droplets, which are assumed to trace vertical air motions because of their limited size. The presence of liquid droplets is confirmed using multiple ground-based remote sensors. Corrections for Doppler spectrum broadening due to turbulence, wind shear, and radar beamwidth are applied. As a result of the turbulence broadening correction, the turbulent dissipation rate can also be estimated. This retrieval is demonstrated using measurements from the Department of Energy (DOE) Atmospheric Radiation Measurement Program’s (ARM) site in Barrow, Alaska, during the Mixed-Phase Arctic Cloud Experiment (MPACE) of autumn 2004. Comparisons of the retrievals with measurements by research aircraft near Barrow indicate that, on the whole, the retrievals perform well. A small bias in vertical velocity between the retrievals and aircraft measurements is found, based on a statistical comparison of four cases comprising nearly 6 h of data. Turbulent dissipation rate comparisons suggest that the radar-retrieved vertical velocity might be slightly underestimated because of an underestimate of the turbulence broadening correction. However, large uncertainties in aircraft vertical velocity measurements likely impact the comparison.
A New Method for Time Series Filtering near Endpoints
Authors: Arguez Anthony , Yu Peng , O’Brien James J. 
Published: April 2008

Abstract
Time series filtering (e.g., smoothing) can be done in the spectral domain without loss of endpoints. However, filtering is commonly performed in the time domain using convolutions, resulting in lost points near the series endpoints. Multiple incarnations of a least squares minimization approach are developed that retain the endpoint intervals that are normally discarded due to filtering with convolutions in the time domain. The techniques minimize the errors between the predetermined frequency response function (FRF)—a fundamental property of all filters—of interior points with FRFs that are to be determined for each position in the endpoint zone. The least squares techniques are differentiated by their constraints: 1) unconstrained, 2) equal-mean constraint, and 3) an equal-variance constraint. The equal-mean constraint forces the new weights to sum up to the same value as the predetermined weights. The equal-variance constraint forces the new weights to be such that, after convolved with the input values, the expected time series variance is preserved. The three least squares methods are each tested under three separate filtering scenarios [involving Arctic Oscillation (AO), Madden–Julian oscillation (MJO), and El Niño–Southern Oscillation (ENSO) time series] and compared to each other as well as to the spectral filtering method—the standard of comparison. The results indicate that all four methods (including the spectral method) possess skill at determining suitable endpoints estimates. However, both the unconstrained and equal-mean schemes exhibit bias toward zero near the terminal ends due to problems with appropriating variance. The equal-variance method does not show evidence of this attribute and was never the worst performer. The equal-variance method showed great promise in the ENSO project involving a 5-month running mean filter, and performed at least on par with the other realistic methods for almost all time series positions in all three filtering scenarios.
Hurricane Katrina Winds Measured by a Buoy-Mounted Sonic Anemometer
Authors: Howden Stephan , Gilhousen David , Guinasso Norman , Walpert John , Sturgeon Michael , Bender Les 
Published: April 2008

AbstractThe eye of Hurricane Katrina passed within 49 n mi of an oceanographic observing system buoy in the Mississippi Bight that is part of the Central Gulf of Mexico Ocean Observing System. Although a mechanical anemometer failed on the buoy during the hurricane, a two-axis sonic anemometer survived and provided a complete record of the hurricane’s passage. This is the first reported case of a sonic anemometer surviving a hurricane and reporting validated data, and it demonstrates that this type of anemometer is a viable alternative to the mechanical anemometers traditionally used in marine applications. The buoy pitch and roll record during the storm show the importance of compensating the anemometer records for winds oblique to the horizontal plane of the anemometers. This is made apparent in the comparison between the two wind records from the anemometers during the hurricane.