Different Types Of Textures Research Articles

Cooling kinetics experiments on different Stromboli lavas: Effects on crystal morphologies and phases composition

Controlled cooling experiments at atmospheric pressure and fO 2 of the NNO buffer were performed on three Stromboli lavas of calcalkaline (CA), high-K calcalkaline (HKCA) and shoshonitic (SHO) affinities. The experiments were conducted at cooling rates of 900 °C/h (fast cooling rate—FCR) and 1 °C/h (slow cooling rate—SCR), respectively, to investigate the kinetic factors governing textural and compositional features such as phase growth morphology, phase relations and phase compositions. The experiments produced different types of textures as both the cooling rate and the quenching temperatures were varied. In general, FCR experiments show a decrease of crystal size as well as a change in crystal shape from euhedral, to granular, to skeletal up to dendritic morphology with decreasing temperatures. SCR experiments produce less variable crystal size and crystal morphology. Measurements of plagioclases indicate that the crystal size and calculated crystal growth are functions of cooling rate; crystal growth rates are about two orders of magnitude higher in FCR experiments than SCR ones. Such textural responses are in agreement with the empirical calibration based on the plagioclase size dependence on cooling rate developed by Cashman (1993). Experimental phase relations display three main features of the crystallization process: (1) the delay in the crystallization of the liquidus phase in the FCR experiments with respect to the SCR ones; (2) crystallization, controlled by the multiphase cotectic relations (plagioclase + pyroxenes ± olivine), is more enhanced for FCR experiments compared to that of SCR ones at the lowest experimental temperature (1100 °C); (3) crystallization of augite and pigeonite is sensitive to cooling rate and system compositions; pigeonite, not found in the natural rocks, crystallizes in the CA sample across SCR and FCR runs, and in the HKCA sample just in the SCR experiments. FCR and SCR experiments produce similar liquid lines of descent for both CA and HKCA starting materials suggesting that the processes of nucleation and growth play reciprocal roles through mass balance as cooling rate varies. This is not true for the SHO composition where the trends of melt composition appear to be especially influenced by the different amounts of olivine crystallization at the different cooling rates. Data on mineral compositions show that plagioclase and clinopyroxene are the phases more strongly affected by the cooling gradients; crystals from SCR experiments and, to a lesser extent, from FCR experiments, show zoning patterns mainly at the lowest experimental temperature.

Recent applications of image texture for evaluation of food qualities—a review

Texture is an important image feature and has been applied greatly in the food industry for quality evaluation and inspection. Recent applications of texture-analysis techniques in the food industry were reviewed in the current paper. There are four different types of texture, i.e. statistical texture, structural texture, model-based texture, and transform-based texture. Statistical texture can be obtained using statistical approachs from the higher-order of pixel grey values of images while structural texture is acquired through some structural primitives constructed from grey values of pixels. Transform-based texture can be obtained by using statistical measurements from the images transformed with certain methods. Model-based texture can be attained by calculating coefficients from a model based on the relationship of the grey values between a pixel and its neighboring pixels. Among them, statistical texture is the most widely used one in the food industry for its high accuracy and less computation time. Transform-based texture and model-based texture are also used, although not as popular as statistical texture. However, structural texture is rarely used in the food industry. Due to the limited understanding of image texture up to now, it is difficult to identify which kind of method is the best for certain application. Therefore, it is expected that by employing different methods together, final results can be improved.

The Control of Texture and Grain Boundary Microstructure by Magnetic Annealing

This paper gives an overview of our recent works on the effect of magnetic annealing, i.e. annealing in a magnetic field, on the evolution of texture and grain boundary microstructure in ultra-fine grained and nanocrystalline magnetic materials differently produced; rapidly solidified Fe-6.5mass%Si ribbons, electrodeposited nanocrystalline nickel, and nanocrystalline Fe78Si9B13 alloy ribbon crystallized from the amorphous state. It was found that the effect of magnetic annealing was powerful and useful for controlling grain growth resulting in the evolution of different types of texture and grain boundary microstructure, depending on the condition of magnetic annealing. In particular, the magnetic crystallization of amorphous Fe78Si9B13 alloy was found to be powerful for producing a nanocrystalline material with a sharp texture and a special grain boundary microstructure.

Fitting of Reciprocal Space Maps of Thin Films with Texture and Stress

Textured thin film of PbTiO3 on glass and both textured and stressed films of TiB2 on iron substrate were investigated by two-dimensional reciprocal space mapping. The texture and residual stress parameters were found by fitting of the measured intensity in the reciprocal space map by the simulated data. Two different types of texture were found in TiB2 for different values of residual stress. The relevance of resulting parameters was checked using different models. Simulation of the data involved a proper empirical texture correction, the Pearson VII profile function, the irradiated volume correction giving a possibility of the film thickness determination, the background, and other correction factors (Lorentz, polarisation).

The perception of doubly curved surfaces from anisotropic textures.

Most existing computational models of the visual perception of three-dimensional shape from texture are based on assumed constraints about how texture is distributed on visible surfaces. The research described in the present article was designed to investigate how violations of these assumptions influence human perception. Observers were presented with images of smoothly curved surfaces depicted with different types of texture, whose distribution of surface markings could be both anisotropic and inhomogeneous. Observers judged the pattern of ordinal depth on each object by marking local maxima and minima along designated scan lines. They also judged the apparent magnitudes of relative depth between designated probe points on the surface. The results revealed a high degree of accuracy and reliability in all conditions, except for a systematic underestimation of the overall magnitude of surface relief. These findings suggest that human perception of three-dimensional shape from texture is much more robust than would be reasonable to expect based on current computational models of this phenomenon.

RHEOLOGICAL PROPERTIES, MICROSTRUCTURE AND SENSORY PERCEPTION OF HIGH‐AMYLOSE STARCH‐PECTIN MIXED GELS

ABSTRACTDifferent types of textures were generated by mixing amylose‐rich HYLON VII maize starch, LM pectin with different Ca contents, with or without saccharose and maltitol. Before mixing, HYLON VII was heated to 150C, which allowed the dispersion of starch amylose and amylopectin. Pectin started to form a gel below 50C and HYLON VII at 20C. The magnitude of G’ and the gelling rate were higher in mixed gels than in the corresponding single gels, at higher calcium contents, and in the presence of saccharose. A dramatic loss of G’ was observed during the reheating of the gels, within the temperature range of 25‐90C for pectin and 55‐90C for HYLON VII. In mixed and saccharose‐containing gels, pectin and starch did not lose gel structure completely. The microstructure of single gels was homogenous, whereas starch aggregates were observed in mixed gels. The sensory profile of single HYLON VII gel differed significantly from other gels; it was smooth, less firm, soft and melted easily in the mouth. The addition of LM pectin to the HYLON VII made the gel less smooth and harder, and structure changed less during reheating. The mixed gel with the lowest Ca content was very smooth, elastic and firm and differed considerably in sensory profile from other mixed gels. The correlation of maximum force of gels in compression with perceived hardness was r=0.89 and that of G’ at 37C with smoothness was r = ‐0.77. The smoothness of the gels was related to the absence of aggregated starch particles.

Microtextural Evolution during Superplastic Deformation in AA8090 Al-Li Alloy

Evolution of microtexture during superplastic deformation (SPD) of an AA8090 SPF grade sheet was investigated. The SPD was performed by tensile testing at 530°C and at a strain rate of 1x10 - 3 /sec, and the microtexture was analyzed by electron back scatter diffraction technique based Orientation Imaging Microscopy (OIM). Prior to the onset of SPD, there was a variation in distribution of different types of textures across the thickness of the sheet. The center location had a predominantly brass-type texture, whereas the surface location had a copper-type texture. The subsequent microtextural determination in samples deformed to various strain levels showed that, there occurred grain growth, grain shape change and textural weakening. The magnitude of these three microstructural changes continuously increased with the amount of SPD. However, there was no evidence of a development of any new type of texture following the deformation. A sample was also statically heated at a higher temperature of 570°C and for a longer time of one hour to simulate the grain growth to the same level as occurred during SPD. It was observed that without deformation the original grain morphology and textures did not change. Therefore, it was concluded that discontinuous recrystallization did not occur during static annealing, and the texture weakening that occurred during SPD was the result of deformation itself and not due to grain growth.

When Texture Takes Precedence over Motion in Depth Perception

Both texture and motion can be strong cues to depth, and estimating slant from texture cues can be considered analogous to calculating slant from motion parallax (Malik and Rosenholtz 1994, report UCB/CSD 93/775, University of California, Berkeley, CA). A series of experiments was conducted to determine the relative weight of texture and motion cues in the perception of planar-surface slant when both texture and motion convey similar information. Stimuli were monocularly viewed images of planar surfaces slanted in depth, defined by texture and motion information that could be varied independently. Slant discrimination biases and thresholds were measured by a method of single-stimuli binary-choice procedure. When the motion and texture cues depicted surfaces of identical slants, it was found that the depth-from-motion information neither reduced slant discrimination thresholds, nor altered slant discrimination bias, compared to texture cues presented alone. When there was a difference in the slant depicted by motion and by texture, perceived slant was determined almost entirely by the texture cue. The regularity of the texture pattern did not affect this weighting. Results are discussed in terms of models of cue combination and previous results with different types of texture and motion information.

Texture Development in Electrodeposited Nanocrystalline Ni-Mn-Fe Alloys

SUMMARYNi-Mn-Fe alloys were electrodeposited from three compositionally altered Ni-Mn electrolytes containing a small amount of FeSO4.(NH4)2SO4.6H2O (10gl−1) Texture development in the resultant codeposits was investigated with opticical colour polarisation microscopy. Addition of Fe in the electrodeposited Ni-Mn system results in the development of additional textures. Most of the samples show three different types of textures though the texture types are characteristic of the bath composition and deposition CD.

Discrimination of planar surface slant from texture: human and ideal observers compared.

In order to quantify the ability of the human visual system to use texture information to perceive planar surface orientation, I measured subjects' ability to discriminate planar surface slant (angle away from the fronto-parallel) for a variety of different types of textures and in a number of different viewing conditions. I measured the subjects' discrimination performance as a function of surface slant, field of view size and surface texture structure. I compared the subjects' performance with that of ideal observers derived for each of the available texture cues--texel position, scaling and foreshortening. The results can be summarized by four points: (i) subjects' discrimination performance improves dramatically with increasing surface slant, tracking the performance of the ideal observers; (ii) subjects can integrate texture information over a large range of visual angles; (iii) comparisons between human subjects and ideal observers show that the human observers rely to some degree on foreshortening information; and (iv) similar comparisons show that in using foreshortening information, subjects rely to some extent on a prior assumption of isotropy.

Remote sensing of sheet metal texture in aluminum alloys

Metal forming operations such as deep drawing, stretching, bending, hemming, etc. are all significantly influenced by the degree of crystallographic anisotropy (texture) present within the workpiece. An effort is underway at Sandia National Laboratories/CA to develop two noncontact ultrasonic systems for the measurement of texture in aluminum sheets. Although the effect of stress wave velocities on elastic anisotropy is well known, its ability to predict plastic behavior has yet to be firmly established. Ultrasonic measurements, which hold the potential for remote, in-process screening, will be shown to exhibit a high degree of correlation with current techniques for measuring texture, which are off-line, destructive, and often inaccurate. Results from an electromagnetic acoustic transducer (EMAT) system are used as a baseline comparison for a more promising noncontact technique involving the optical generation and detection of ultrasound, commonly referred to as laser ultrasonics (LU). In addition to displaying the level of anisotropy, slowness curves obtained from these systems suggest the ability to distinguish between different types of texture, as predicted from theory.

On anisotropic finite deformation plasticity Part II. A two-component model

The anisotropic plastic behavior of materials during finite deformation is partly due to the development of different types of textures or substructures. In order to describe phenomenologically this behavior, a two-component model of finite plasticity is proposed based on the scale invariance approach earlier advanced by Aifantis and co-workers. Each component follows its own evolution and rotation rules to account for the different textures occurring during the deformation process. A direct extension of this framework to consider viscoplastic effects is also developed. The model is applied to simulate the anisotropic deformation behavior of materials under tension, compression and torsion. The results are compared with available experimental data and related predictions of polycrystalline plasticity models. It is shown that the present continuum model has the advantages of both accuracy and simplicity as compared to polycrystalline calculations.

Texture characterization using robust statistics

The purpose of texture characterization is to produce a set of measurements which identify different types of textures. It is desirable to use measurements which produce unique characteristics for each type of texture. This allows a texture class to be described by a set of parameters or features which can be used by a segmentation algorithm to partition an image into homogeneous texture regions. Since texture features ultimately find their use in segmentation algorithms, it is more appropriate to consider those features which can effectively characterize the textures in the images being segmented. In many applications, particularly medical imaging, the types of textures are known a priori. It is unnecessary to make invalid assumptions about the types of textures which the features can effectively detect. In this paper, a new framework is presented to evaluate a given set of texture features, based on the set of textures they are to characterize. The textures are sampled from “real” images which are to be segmented, rather than the commonly used Brodatz textures. Using robust statistics, the number of outliers produced by each feature is used to determine its effectiveness in characterizing the set of textures. The proposed framework is applied to a set of textures sampled from a sequence of diagnostic ultrasound images of an ovary in vitro. Thirty-two spatial and frequency domain texture features are evaluated. Numerous experiments are performed to evaluate the ability of the texture characterization framework to characterize the textures present in ultrasound images. It is found that the texture classes present in the ultrasound images could be uniquely characterized at all resolutions, independent of orientation. The experimental results suggest that the proposed framework, together with the use of robust statistics, can provide a ranking on the effectiveness of the features and thus can determine better features for a latter segmentation process.

Microstructural study of the crystallization product of the Co100−xPx amorphous system

The crystallization process of amorphous electrodeposited samples of composition Co100–xPx (10 < x < 25) has been monitored by differential scanning calorimetry (DSC) and the resulting microstructure has been studied by scanning electron microscopy (SEM) and x-ray diffraction (XRD). Samples of composition given by x 21 crystallize through a single one. Depending on the composition and crystallization stage, activation energies varying from 1.76 to 2.02 eV and frequency factors of the order of 1013–1014 s–1 have been evaluated. The DSC measurements are compatible with the coexistence of two amorphous phases with different compositions in the regions that are located near the edges of the samples. The analysis of the microstructure resulting from crystallization has shown the existence of two different types of texture for samples with values of x respectively above and below 21, as well as the presence of linear structures oriented perpendicular to the plane of the samples. The development of these features can be attributed to the fundamental role that the polarization, due to magnetization, plays in the crystallization process of this system. A gradual variation of the grain size has also been observed, indicating that crystallization takes place by an inhomogeneous nucleation and growth mechanism.

Texture distribution through-the-thickness after cold-rolling of 3% silicon steel

A simple laboratory technique was used to produce cold-rolled specimens with various reductions from 40 to 80% at a 10% interval starting with commercial hot band of 3% silicon steel. The quantitative and sensitive Orientation Distribution Function (ODF) method was applied to analyze the evolution of texture from hot-rolled to cold-rolled through-thickness. The results indicated that there are two different types of texture in hot sheet which are called recrystallization type texture and deformation type texture. The developed texture at each level of cold sheet specimens was inherited from the texture at respective level of hot sheet. The Goss texture memory effect at subsurface level was discussed. The conclusions indicated that it is important to get suitable hot band which has strong recrystallization type texture at its surface level and use appropriate cold rolling reduction for producing cold band which has a texture distribution of strong {111}〈112〉, weak {001}〈110ång; and some {110}〈001〉 components at its subsurface level and is beneficial to forming sharp Goss texture during recrystallization. The appropriate reduction is about 70%.

Growth of the Bi-Sb superlattice

Bi-Sb multilayered thin films described in the paper were produced by evaporation in a diffusion vacuum system. X-ray diffraction measurements were the main method of investigating the structure of the films. Depending on the substrate temperature during the preparation of the samples, different types of texture were observed: (110) or/and (111). The samples produced at 170 K (showing strong (110) texture) were subjected to a detailed scrutiny. Computer-simulated X-ray spectra based on a statistical model of the superlattice structure were applied in the analysis.

Texture and its Influence on the Mechanical and Ballistic Properties of Steel Armor Plates

By appropriate thermomechanical processing treatment in the austenite region of a medium carbon 5Ni steel, three different types of textures, each with various degrees of intensity, have been produced in the quenched‐and‐tempered high‐hardness steel armor plates. The various mechanical properties, including tension, through‐thickness tension and compression, impact, fatigue, and fracture toughness, together with the ballistic performance of the plates as a function of the intensity of the texture, in particular the (112)+(111) type, are presented and discussed.