Radial Texture Research Articles

Evolution of Radial Texture and Microhardness of Cu-Nb Composite Wires

Evolution of Radial Texture and Microhardness of Cu-Nb Composite Wires

Wood board image processing based on dual-tree complex wavelet feature selection and compressed sensing

In order to identify wood surface types and carry out board grading, a collaborative classification method without image segmentation is proposed to sort four wood surface types: radial texture, tangential texture, live knot and dead knot. Firstly, three-level dual-tree complex wavelet decomposition is applied to the board image and 40-dimensional feature vector is obtained; secondly, particle swarm optimization (PSO) algorithm is used for feature selection and dimension reduction, and after optimization 11 key features are chosen; finally, the surface types are identified by compressed sensing classifier based on the features optimized by PSO. Four types of Xylosma samples are used for the experiment. The classification accuracy of the above four types are 100, 86.7, 96.7 and 86.7 %, respectively. Theoretical and experimental results show that the direction property of dual-tree complex wavelet can express the complex information of wood surface and the classification realized by compressed sensing is effective.

Using computer vision and compressed sensing for wood plate surface detection

Aiming at detecting the random and complicated characteristic of wood surface, we proposed a comprehensive detection algorithm based on computer vision and compressed sensing. First, integral projection method was used to trace and locate the position of a wood plate; then surface images were obtained by blocks. Second, multiscaled features were extracted from image to express the surface characteristic. Third, particle swarm optimization algorithm was used for multiscaled features selection. Finally, the defects and textures were detected by compressed sensing classifier. Five types of wood samples, including radial texture, tangential texture, wormhole, live knot, and dead knot, were used for tests, and the average classification accuracy was 94.7%.

Evolution of Drawing Texture for A6 Aluminum Conductor

Evolution of drawing texture for A6 aluminum conductor with the drawing process was investigated by macro and micro-texture analysis. The results show that the fiber-like deformation texture of 111 and 100 formed in the drawing process, and 100 texture reduced while 111 texture enhanced with the increasing strain. The distribution of deformed texture was of homogeneity along the radial direction of wire: the deform texture transformed from strong 100 texture(~52% volume fraction) in the surface to strong 111 texture(~55%) in the center by moderate strains; the radial gradient texture was weakened and a strong 111 texture(70%) formed in the overall wire by high strains. Moreover,the core hardness of the wire was higher than that of the surface, which attributed to the texture gradient distribution along the radial. Adjusting the drawing process to optimize the dislocation density and texture as well as their distribution in the wire is an effective route to improve the strength and conductive properties of the A6 aluminum conductor.

The effect of pressure pulses on isotactic polypropylene crystallization

High hydrostatic pressure pulses, up to 80MPa, have been imposed for different time and at various temperatures on molten iPP during cooling. The absence of any effect on the crystallization behavior after pressure release and further cooling demonstrates either that no nucleation precursor is produced by this thermo-mechanical history or that the lifetime of pressure-induced precursors is extremely short, as if no crystallization occurs during pressurization. Even when crystals develop during the pressurized stage, when high pressure is released, subsequent crystallization takes place in the same temperature range in which the polymer crystallizes at atmospheric pressure.Structure and morphology of samples partially crystallized under pressure were investigated. WAXD show that, as expected, the fraction of γ-crystallinity firstly increases with increasing the time under pressure up to impinging of γ-spherulites and then levels off at a constant value. Morphological investigation performed on microtomed samples reveals that the γ-spherulites formed under high pressure exhibit positive birefringence and that their skeleton continues to grow during cooling when pressure is released. On heating, these spherulites melted first, but incompletely: the radial lamellar texture is still present up to relatively high temperature. These features seem to be consistent with the spherulitic architecture described by Lotz: infilling γ-lamellae grow by epitaxy on a skeleton of α-lamellae. Under the adopted experimental conditions, pre-imposed pressure pulses do not promote formation of extra nuclei, while they largely affect the crystal structure and the morphology of melt crystallized isotactic polypropylene.

Current-induced Orbital and Spin Magnetizations in Crystals with Helical Structure.

We theoretically show that in a crystal with a helical lattice structure, orbital and spin magnetizations along a helical axis are induced by an electric current along the helical axis. We propose a simple tight-binding model for calculations, and the results can be generalized to any helical crystals. The induced magnetizations are opposite for right-handed and left-handed helices. The current-induced spin magnetization along the helical axis comes from a radial spin texture on the Fermi surface. This is in sharp contrast to Rashba systems where the induced spin magnetization is perpendicular to the applied current.

Direct Carbonization of High-performance Aromatic Polymers and the Production of Activated Carbon Fibers

For expanding the utilization of several high-performance aromatic polymeric fibers, e.g., poly p-phenylene benzobisoxazole (PBO, Zylon®), poly p-phenylene terephthalamide (PTA, Kevlar 29®), and polyarylate (PA, Vectran®), direct carbonizing and graphitizing behaviors have been investigated. The PBO-based carbon fiber showed a typical radial texture on its fracture surface, and the graphitization degree (P1) reached 0.35 and crystallite sizes of Lc(002), La(110) after graphitization exceeded 30 nm. On the other hand, the P1 indices of the graphitized carbon fibers from PTA and PA were no more than 0.15. However, a low P1 value is preferable for the production of activated carbon fibers (ACF). In addition, on the surface of the PA-based carbon fibers produced at 900°C, some fine mesh-like morphologies were observed indicating the formation of a porous carbon structure. In contrast, for the PTA-based carbon fibers the development of radial texture could be seen only partially on the fracture surface, and porous morphologies were not recognizable. It was confirmed that the direct carbonization was enough to convert PA fibers into ACF. The BET surface area of the PA-based carbon fibers increased up to 900~1,000 m2/g after the direct carbonization at 900 oC, and exceeded 1,000 m2/g easily when activated.

Modified Approach for Quantitative Texture Evaluation in Case of Transverse Textured Zirconium Alloy Tubes

Abstract The crystallographic texture of fabricated components from zirconium alloy has a significant effect on their in-service performance because of texture-dependent properties. Quantitative characterization of this texture in various zirconium alloy tube samples was conducted using pole figure technique and Kearns methodology. Corresponding texture parameters were calculated for both the methods and were found to be similar for samples with strong radial texture. However, the same was not true for samples with transverse texture because of a defocusing error coming due to the geometry of a conventional pole figure technique. Hence, a modified method for such samples by pole figure method was developed which, in addition, solved the difficulties associated with both sample preparation and experiment for the Kearns method or complete pole figure method to a great extent.

A lumen detection-based intestinal direction vector acquisition method for wireless endoscopy systems.

This paper proposes a novel method for acquiring an intestinal direction vector (IDV) based on a single static wireless endoscopic image. The IDV can be used for navigation of wireless capsule endoscopy, and for multicamera microball system, this information can help to select cameras to capture images of the region of interest. Our proposal is based on lumen detection, which involves Bayer-format downsample, adaptive threshold segmentation, and radial texture detection. Then, an IDV calculation method with only one single static image by modeling the small intestine and image capture process is put forward. The performance of the proposed method is verified with experiments based on real digestive tract images and the microball demo system. The lumen detection method achieves 95.5% precision and 98.1% sensitivity. The experimental results in pig intestine show that the error of IDV is limited by a sphere with center (-0.00629, 0.00097, 0.00061) and radius 0.085.

КОЛЬЦЕВЫЕ МАГНИТЫ С РАДИАЛЬНОЙ ТЕКСТУРОЙ ДЛЯ ДИНАМИЧЕСКИ НАСТРАИВАЕМЫХ ГИРОСКОПОВ

КОЛЬЦЕВЫЕ МАГНИТЫ С РАДИАЛЬНОЙ ТЕКСТУРОЙ ДЛЯ ДИНАМИЧЕСКИ НАСТРАИВАЕМЫХ ГИРОСКОПОВ

Radial crystalline texture in a lyocell fibre revealed by synchrotron nanofocus wide-angle X-ray scattering

Within-fibre variability of the degree of preferred orientation of cellulose crystals and crystallinity was studied in lyocell. Wide-angle X-ray scattering experiments were performed with whole single fibres and thin axial fibre sections at the synchrotron nanofocus beamline at the European Synchrotron Radiation Facility. Experimental evidence demonstrates that skin–core differences in the degree of preferred orientation of crystals in lyocell are more pronounced than experiments with whole single fibres are capable of revealing. Similar differences in crystallinity are detected in thin sections whereas they remain obscured in whole single fibres due to averaging. Finally, substantial evidence for a radial crystal texture in lyocell is provided.

Environmental and sequence stratigraphic implications of anhydrite textures: A case from the Lower Triassic of the Central Persian Gulf

The Lower Triassic Kangan Formation in the Persian Gulf (South Pars Gas Field) and its adjacent areas are composed of carbonate–evaporite sequences. These sediments were deposited in a shallow marine homoclinal ramp. Study of the anhydrite-bearing intervals shows various structures and textures. The anhydrite structures are mainly bedded, massive, chicken-wire and nodular type and the main textures are felted, sparse crystal, needle shape, lath shape, equant and fibrous. Pervasive and poikilotopic cement together with replacement and porphyroblastic gypsum are accounted as the most common diagenetic features in anhydrite. Evaluation of anhydrite occurrences and features support both primary and secondary formations. The nodular to chicken-wire anhydrite formed under synsedimentary sabkha conditions, whereas anhydrite cements occurred during the late stages of diagenesis (shallow burial stage). Massive to bedded anhydrite could have been formed under subaqueous conditions or originated by coalescing and continued growth of anhydrite nodules in the sabkha zone. Anhydrite fabrics impose a significant control on the reservoir quality of the Kangan carbonates at the South Pars Gas Field. Thick massive and bedded anhydrite could have been formed as an intraformational seals and anhydrite cements occluded pore spaces and reduced the poroperm values. The sequence stratigraphic analysis revealed two depositional sequences in the studied intervals, which are composed of TST and HST. Investigation of anhydrite throughout depositional sequences indicates a change in the content and style of anhydrite texture. Anhydrite content (volume) decreases upward through transgressive system tract (sea-level rise) whereas, it enhances during highstand system tract (sea-level fall). Pervasive and poikilotopic anhydrite cements together with replacement by anhydrite are prevalent features during transgressive and early highstand system tract. At the late HST, with a progradational stacking pattern, anhydrite value increases and felted, radial, equant, crystalline and mosaic texture are the most common anhydrite fabrics. Sequence boundaries that indicate maximum sea level fall and exposure of successions are marked by the broad anhydrite deposits with massive to bedded and chicken-wire structures and various textures that located in late HST package. There is an unambiguous relationship between the microfacies associations, the evaporite textures, and the sea-level fluctuations. This relationship could lead to a predictable pattern that can be of use as a general guide for the sequence stratigraphic interpretations in the area.

Carbon black modification of mesophase pitch-based carbon fibers

The effects of carbon black (CB) on the microstructural development within mesophase pitch-based carbon fibers are reported. Unlike carbon nanotubes, which were previously studied for modifying fiber microstructure, CB represents a significantly lower cost alternative making it more favorable for industrial application. Additionally, the aspect ratio of CB is much closer to unity than carbon nanotubes, which have an aspect ratio ∼100 to 1000. Fibers were produced by first dispersing CB into a synthetic mesophase pitch at a dilute concentration of 0.3wt%. These precursor materials were spun and then processed into carbon fibers. Unmodified (0wt%) carbon fibers exhibited a severe radial texture with increasing orientation of graphitic pleats away from the fiber core. Carbon fibers modified with CB showed a strong flat layer structure, with only a slight increase in pleat folding away from the core. This difference in structure was also accompanied by a decrease in the number of fibers that exhibited “pac-man” splitting. No discernable reduction was observed in the graphitic crystallinity (interplanar spacing and crystallite size) or axial orientation of crystallites within the fiber, as a result of nanomodification.

Statistical analysis on morphology development of some semialicyclic polyimides using atomic force microscopy

The morphological features and surface texture parameters of some polyimide films prepared from a flexible and alicyclic dianhydride, in combination with five aromatic diamines, were evaluated by atomic force microscopy (AFM) in order to determine their applicability in electronics. By means of the surface roughness, shape of the surface height distribution, and angular and radial texture, a precise description of the actual surface topographies at the interface with other materials was made. The polyimide structures led to the development of different surface morphologies (from granular to porous and from bumpy to spiky). The relief diversity was described by the entropy of morphology, which had a similar trend with the root mean square roughness, which presents low values, i.e. 0.5-1.8 nm. Three-dimensional AFM images and the corresponding angular spectra, together with texture aspect ratio and texture direction index (close to 1), indicate that no predominant orientation exists on the investigated surfaces. The redundancy in the morphology was associated with the concept of fractals, the maximum redundancy being achieved for the polyimide with the most complex polymer chain conformation. These results provide useful insights in selecting the polyimide structure, which has the optimal morphology, roughness, orientation, bearing properties, or self-similarity for microelectronic applications such as: substrate for display backplanes, planar technology, microelectronic packaging, etc.

Prelamination of Radial Forearm Free Flap with Buccal Mucosa

Reconstruction of extripative defects in the head and neck with vascularized free tissue transfer has become the standard of care. In order to overcome disadvantages of the traditional radial forearm free flap (RFFF), e.g., color and texture difference, bulk, and donor site morbidity, the concept of prelamination of the RFFF with mucosa was developed. The term prelamination, introduced in 1994, is a process in which tissue is implanted into a vascular flap prior to transfer [1]. Prelamination with oral mucosa has been implemented in the reconstruction of a variety of intraoral and facial defects [2–4]. With their high cell renewal rate, morcelized buccal mucosal grafts can spread over a vascularized fascial bed and become functional in 3 weeks [2]. The resultant mucosa resembles the native oral mucosa both macroscopically and histologically [5], providing lubrication. Fasicomucosal flaps are thinner than fasciocutanous flaps since no subcutaneous tissue is included. This allows for better tongue mobility and rehabilitation [2]. We studied patients who underwent reconstruction with a prelaminated radial forearm fasciomucosal flap (RFFMF) to describe surgical technique and report multi-institutional outcomes.

Tailings Reservoir Recognition Factors of the High Resolution Remote Sensing Image in Southeastern Hubei

Tailings with the characteristics of very small particles determine their high reflectivity of each band in remote sensing images.The accumulation process of the tailings determines their unique surface texture,including parallel zoning texture features and radial texture features.The authors mainly studied spectral features,texture features and some other features such as roads,mine buildings,reservoirs distribution and their geographical position which are associated with the tailings reservoir,and established the comprehensive recognition factors of the tailings reservoir in high resolution remote sensing image in this paper.On the basis of these factors,the tailings reservoirs can be identified and their scales can be preliminary determined from WorldView-2 images.

A comparison of the effect of graphitization on microstructures and properties of polyacrylonitrile and mesophase pitch-based carbon fibers

Polyacrylonitrile (PAN) and mesophase pitch (MPP)-based carbon fibers were heat treated in the temperature range of 1300–2700°C. After high-temperature heat treatment (HHT), the microstructures and mechanical properties of PAN and MPP-based carbon fibers were investigated. For both series of carbon fibers, the Young’s modulus increased with heat treatment temperature increasing. The tensile strength of PAN-based carbon fibers decreased, while that of MPP-based carbon fibers increased. After HHT at 2700°C, the tensile strength of MPP-based carbon fibers exceeded that of PAN-based carbon fibers. The results could be ascribed to the variously original structures and the different routines of structural evolution. The physical entanglements and covalent cross-links of carbon ribbons in PAN-based carbon fibers contributed to a higher shear stress between the graphene layers, however, tended to generate voids and cracks during HHT due to an extensive transformation from turbostratic to ordered structure along with nitrogen removing. For MPP-based carbon fibers, they displayed a radial texture with ordered and parallel packing of layers in the transverse section. Thus, it was easier for the graphene layers to stack and bond to the adjacent ones without strong rotations, leading to fewer voids and cracks.

The Effect of Microstructure on Delayed Hydride Cracking Behavior of Zircaloy-4 Fuel Cladding—An International Atomic Energy Agency Coordinated Research Program

Abstract The rate of delayed hydride cracking (DHC) has been measured in Zircaloy-4 fuel cladding in several metallurgical conditions using the pin-loading tension technique. In light water reactor (LWR) cladding in the cold-worked and cold-worked and stress-relieved conditions, the cracking rate followed Arrhenius behavior up to about 280 °C, but at higher temperatures the rate declined with no cracking above 300°C. Non-LWR cladding appeared to behave in the same manner. In LWR cladding in the recrystallized condition, the cracking rate was highly variable because it depended on KI within the test range up to 25 MPa√m, whereas in the other LWR claddings, cracking rate was independent of KI, indicating that KIH was below 11 MPa√m. The main role of microstructure was to control the material strength; the cracking rate increased as the strength increased. Although all the claddings had a radial texture, it did not protect the cladding from DHC. The DHC fracture surface consisted of flat broken hydrides, often in arcs, but no striations were observed, except in one specimen subjected to thermal cycles.

Anisotropic thermal creep of internally pressurized Zr–2.5Nb tubes

The anisotropy of creep of internally pressurized cold-worked Zr–2.5Nb tubes with different crystallographic textures is reported. The stress exponent n was determined to be about three at transverse stresses from 100 to 250 MPa with an activation energy of ∼99.54 kJ/mol in the temperature range 300–400 °C. The stress exponent increased to ∼6 for transverse stresses from 250 to 325 MPa. From this data an experimental regime of 350 °C and 300 MPa was established in which dislocation glide is the likely strain-producing mechanism. Creep tests were carried out under these conditions on internally pressurized Zr–2.5Nb tubes with 18 different textures. Creep strain and creep anisotropy (ratio of axial to transverse steady-state creep rate, ε ˙ A / ε ˙ T ) exhibited strong dependence on crystallographic textures of the Zr–2.5Nb tubes. It was found that the values of ( ε ˙ A / ε ˙ T ) increased as the difference between the resolved faction of basal plane normals in the transverse and radial directions ( f T − f R ) increases. The tubes with the strongest radial texture showed a negative axial creep strain and a negative creep rate ratio ( ε ˙ A / ε ˙ T ) and tubes with a strong transverse texture exhibited the positive values of steady-state creep rate ratio ( ε ˙ A / ε ˙ T ) and good creep resistance in the transverse direction. These behaviors are qualitatively similar to those observed during irradiation creep, and also to the predictions of polycrystalline models for creep in which glide is the strain-producing mechanism and prismatic slip is the dominant system. A detailed analysis of the results using polycrystalline models may assist in understanding the anisotropy of irradiation creep.

Mechanism of formation of texture and its influence on the strength of thermoelectric p-Bi0.5Sb1.5Te3

It is established that, in preparing p-Bi0.5Sb1.5Te3 by vertical zone melting, in addition to the directional texture (characteristic of materials exhibiting a highly anisotropic growth rate) in which the cleavage planes of crystal grains are parallel to the direction of propagation of the crystallization front, other texture types can arise, in which the orientation of grain cleavage planes is ordered in a cross-sectional plane of the ingot. Two types of such textures, “radial” and “circular,” were observed. In a radial texture, the lines of intersection of grain cleavage planes with a cross-sectional plane of the ingot are oriented along radii of this cross section and, in a circular texture, these lines of intersection are oriented approximately perpendicular to a radius crossing the grain. The formation of a radial texture is associated with rotation of the ampoule with the crystallizing substance about its vertical axis causing centrifugal flows of the melt. The formation of a circular texture is associated with the orientation effect of the ampoule walls and with circular motion of the melt during torsional oscillations of the ampoule about the vertical axis. Ingots with a radial texture exhibit much lower resistance to splitting along their axis than ingots with a circular texture do. An explanation is provided for this fact.