Oblique Component Research Articles

Texture Formation and Swift Effect in High Strain Torsion of NiAl

Texture formation and Swift effect were investigated in torsion deformed NiAl. High-strain torsion of solid bars was done with a Paterson rock deformation machine at temperatures between 700 K and 1300 K under a confining pressure of 400 MPa. The maximum shear strains and shear strain rates applied were 19×10−4 s−1 and 2.2×10−4 s−1, respectively. Textures were measured by diffraction of neutrons, electrons, and synchrotron radiation. The textures consist of an oblique cube and Goss component, the intensity of which depends on the initial texture and deformation temperature. The axial lengthening and shortening observed are related to the Goss and the oblique cube components, respectively. There is qualitative agreement between experiment and simulation at low temperature and low shear strains. With increasing temperature, continuous and discontinuous dynamic recrystallization take place, strongly influencing the development of texture and Swift effect.

Steeply-dipping extension fractures in the Newark basin, New Jersey

Late Triassic and Early Jurassic bedrock in the Newark basin is pervasively fractured as a result of Mesozoic rifting of the east–central North American continental margin. Tectonic rifting imparted systematic sets of steeply-dipping, en échelon, Mode I, extension fractures in basin strata including ordinary joints and veins. These fractures are arranged in transitional-tensional arrays resembling normal dip-slip shear zones. They contributed to crustal stretching, sagging, and eventual faulting of basin rift deposits. Extension fractures display progressive linkage and spatial clustering that probably controlled incipient fault growth. They cluster into three prominent strike groups correlated to early, intermediate, and late-stage tectonic events reflecting about 50– 60° of counterclockwise rotation of incremental stretching directions. Finite strain analyses show that extension fractures allowed the stretching of basin strata by a few percent, and these fractures impart stratigraphic dips up to a few degrees in directions opposing fracture dips. Fracture groups display three-dimensional spatial variability but consistent geometric relations. Younger fractures locally cut across and terminate against older fractures having more complex vein-cement morphologies and bed-normal folds from stratigraphic compaction. A fourth, youngest group of extension fractures occur sporadically and strike about E–W in obliquely inverted crustal blocks. A geometric analysis of overlapping fracture sets shows how fracture groups result from incremental rotation of an extending tectonic plate, and that old fractures can reactivate with oblique slip components in the contemporary, compressive stress regime.

Prediction of postoperative astigmatism in cataract surgery

Background: The purpose of this study was to predict postoperative astigmatism using refraction, keratometry, and other preoperative information after phacoemulsification with posterior chamber intraocular lens (IOL) implantation. Methods: A retrospective study was conducted of 176 eyes of 161 patients undergoing phacoemulsification for visually significant cataract with capsular bag or sulcus IOL fixation at the Hunter Holmes McGuire Veterans Administration Medical Center, Richmond, Va. Eyes with complications and final-corrected visual acuity of less than 20/60 were excluded. Keratometric and refractive astigmatism were described by Jackson cross-cylinder with-the-rule (J 0) and oblique (J 45) components. Preoperative predictors of postoperative refractive J 0 and J 45 were determined by univariate and multivariate regression analysis. Results: The final multivariate model to predict postoperative with-the-rule astigmatism was J 0Postoperative = 0.24 × J 0Preoperative 0.46 × J 0Keratometic − 0.08 (coefficient of determination [r 2] = 0.51, all p < 0.001). The multivariate model based on expected predictors of oblique astigmatism was J 45Postoperative = 0.10 × J 45Preoperative + 0.23 × J 45Keratometric + 0.01, (r 2 = 0.05, p = 0.09 for J 45Preoperative and 0.03 for J 45Keratometric). Temporal clear cornea (as opposed to superior scleral tunnel) incisions, and use of sutures in scleral tunnel incisions, were not predictive of postoperative astigmatism. Interpretation: Postoperative astigmatism can be estimated from preoperative astigmatism using the following weighted average: two-thirds keratometric and one-third refractive astigmatism. Preoperative refraction may predict postoperative astigmatism independent of keratometry because keratometry reflects only the paracentral anterior (not posterior) corneal curvature.

Quantification of sphero-cylindrical defocus using refractive data

Purpose To compare various indices calculated using refractive data to quantify defocus. Methods Subjective refraction, pupil diameter (Colvard) and asphericity (Orbscan) were prospectively recorded in 200 healthy eyes (including ametropia) of 121 patients. Refractive data were expressed by a sinusoidal curve in one plane (power / meridian) and by a vector in a 3D dioptric power space. The three Cartesian coordinates of the vector respectively represented the spherical equivalent, WTR/ATR component (0°/90° Jackson), and oblique component (45°/135° Jackson). The defocus was quantified by the root-mean-square (RMS) value of the power curve and the length of the vector. Correlations between uncorrected visual acuity (UCVA) in LogMAR units and principal parameters including defocus indices and refractive parameters were analyzed. Results The length of the power vector and the RMS index provided the highest correlation with UCVA (rs=0.90 p<0.001 and rs=0.88 p<0.001, respectively), whereas the correlation was less strong for subjective spherical equivalent (rs=0.70 p<0.001) and subjective cylinder (rs=0.30 p<0.001). Correlation was poor for the pupil diameter (rs=0.20, p<0.001); sex and asphericity coefficient showed no significant correlation (rs<0.08 p>0.20) with UCVA. Conclusion The length of the sphero-cylindrical vector is clinically relevant to quantify the defocus with the aid of a single index using both spherical and astigmatic components of refraction. The UCVA is mainly explained by the ametropia.

Quantification of sphero‐cylindrical defocus using refractive data

Abstract Purpose To compare various indices calculated using refractive data to quantify defocus. Methods Subjective refraction, pupil diameter (Colvard) and asphericity (Orbscan) were prospectively recorded in 200 healthy eyes (including ametropia) of 121 patients. Refractive data were expressed by a sinusoidal curve in one plane (power / meridian) and by a vector in a 3D dioptric power space. The three Cartesian coordinates of the vector respectively represented the spherical equivalent, WTR/ATR component (0°/90° Jackson), and oblique component (45°/135° Jackson). The defocus was quantified by the root‐mean‐square (RMS) value of the power curve and the length of the vector. Correlations between uncorrected visual acuity (UCVA) in LogMAR units and principal parameters including defocus indices and refractive parameters were analyzed. Results The length of the power vector and the RMS index provided the highest correlation with UCVA (rs=0.90 p&lt;0.001 and rs=0.88 p&lt;0.001, respectively), whereas the correlation was less strong for subjective spherical equivalent (rs=0.70 p&lt;0.001) and subjective cylinder (rs=0.30 p&lt;0.001). Correlation was poor for the pupil diameter (rs=0.20, p&lt;0.001); sex and asphericity coefficient showed no significant correlation (rs&lt;0.08 p&gt;0.20) with UCVA. Conclusion The length of the sphero‐cylindrical vector is clinically relevant to quantify the defocus with the aid of a single index using both spherical and astigmatic components of refraction. The UCVA is mainly explained by the ametropia.

Resolving Milankovitchian controversies: The Triassic Latemar Limestone and the Eocene Green River Formation

Although orbital forcing is commonly proposed as the driver of ancient sedimentary rhythms, the lack of adequate independent time control (radio isotopic data) to calibrate these cycles has stood as a major challenge to evaluation of the hypothesis. Here I apply a new statistical approach to evaluate cyclicity in two historically important rhythmic units for which orbital forcing has been proposed: the Triassic Latemar Limestone (Dolomites, Italy) and the Eocene Green River Formation (Wyoming, USA). A major advance of the new method is its explicit evaluation of the null hypothesis of no orbital signal. The null hypothesis can be rejected with a high degree of confi dence in the Latemar Limestone (probability <0.30%) and Green River Formation (probability <0.07%). The analyses also resolve controversies about the specifi c orbital calibrations at each site. Both data series reveal the expected precession, obliquity, and eccentricity orbital components, and yield astrochronologies that are consistent with proposed radio isotopic based time scales.

Effect of three‐dimensional slab geometry on deformation in the mantle wedge: Implications for shear wave anisotropy

Shear‐wave splitting observations from many subduction zones show complex patterns of seismic anisotropy that commonly have trench‐parallel fast directions. Three‐dimensional flow may give rise to trench‐parallel stretching and provide an explanation for these patterns of seismic anisotropy. Along‐strike variations in slab geometry produce trench‐parallel pressure gradients and are therefore a possible mechanism for three‐dimensional flow. In this study we quantify the effects of variable slab dip, curved slabs, oblique subduction, and slab edges on flow geometry and finite strain in the mantle wedge of subduction zones. Temperature, dynamic pressure, velocity, and strain are calculated with high‐resolution three‐dimensional finite element models. These models include temperature‐ and stress‐dependent rheology and parameterized slab and trench geometry. Thick layers (20–60 km) with strong trench‐parallel stretching are observed in the mantle wedge when slab geometry involves a transition to slab dip less than 15° or strong curvature in the slab. In these cases, strong trench‐parallel stretching develops when flow lines have an oblique to trench‐normal orientation. This suggests that trench‐parallel seismically fast directions may not indicate trench‐parallel flow lines in systems with large along‐strike variations. An oblique component of stretching is confined to a 20–30 km layer above the slab in systems with oblique subduction. The effects of slab edges include strong toroidal flow and focusing in the mantle near slab edges and trench‐parallel flow that extends 50–100 km into the core of the mantle wedge.

Influence of Dynamic Recrystallisation on Texture Formation in ECAP deformed Nickel

3N nickel has been deformed by equal channel angular pressing (ECAP) at 400°C up to 3 passes using route A. The texture with respect to position in the deformed billet, i.e. from top to bottom, has been measured with high-energy synchrotron radiation. It is characterized by texture components typical for simple shear in the intersection plane of the square-shaped 90° bent channel. Besides, an oblique cube component is observed. Orientation imaging microscopy clearly shows that this component is due to partial recrystallization. Intensities of the texture components as well as deviations from their ideal shear positions vary from the top to the bottom of the billet and with the number of passes. The change of the intensity of texture components and the texture gradient investigated is discussed. Special emphasis is put on the influence of dynamic recrystallization on texture and microstructure formation during ECAP of fcc metals.

A cognitive and an affective dimension of alexithymia in six languages and seven populations

The Dutch Bermond–Vorst Alexithymia Questionnaire (BVAQ) is translated into various languages. The aim of this research was to establish the factor structure of subscales on seven cultural groups. The BVAQ consists of five subscales of eight items each: Emotionalising, Fantasising, Analysing, Identifying, and Verbalising emotions. The BVAQ was administered to a group of Dutch students (n=375), a group of English students (n=175), a group of Australian students, university employees and visitors (n=216), a group of French speaking Belgian students (n=175), a group of Italian people (n=791; a mix of various clinical groups), a group of Polish people (n=427; also a mix of various clinical groups) and a group of Russian people (n=141; general population). The hypothesised two-factor structure of an affective alexithymia dimension (Emotionalising, Fantasising) and a cognitive alexithymia dimension (Insight and Verbalising), with “Analysing emotions” loading on both factors, was clearly supported by confirmatory factor analyses (CFA). Both orthogonal and oblique principal components analyses (PCA), without restriction concerning the number of factors, provided the same two-factor solution in all groups explaining between 55% and 64% of the variance. Oblique rotation further demonstrated that the correlations between these two factors were low in all populations. The combined CFA and PCA results, therefore, indicated that a model with two independent factors has to be preferred over the model assuming two correlated factors.

Coevolution of continental ice cover and permafrost extent over the last glacial‐interglacial cycle in North America

The bed thermal characteristics of a glacial systems model that has been calibrated against a large set of relative sea level, geodetic, and strandline observations are examined for the previously glaciated sector of the North American continent. The model compares favorably against the present‐day extent of permafrost and against the observed temperature profiles from three deep boreholes when appropriate bed thermal conductivities are employed. Estimates for the present‐day depth field of the lower permafrost boundary are presented. We find a significant disequilibrium in the lower permafrost boundary for most of the Arctic region, with present‐day depth as much as 250 m shallower than the equilibrium value for present‐day climate forcing. This is largely due to the ongoing response to the loss of ice cover from the glacial period. The time evolution of the subglacial warm‐based area fraction is also presented together with calibration‐derived confidence intervals. A peak warm‐based fraction of 50% ± 6% is obtained at Last Glacial Maximum. The timing of the three largest ice volume maxima that were produced in response to the obliquity component of orbital forcing during the last glacial cycle matches that of the maxima for the warm‐based area fraction with no significant phase delay. Warm‐based conditions are required to enable ice streaming (fast flow) in the model. It is therefore hypothesized that the expansion of the area covered by warm‐based ice played a critical role in producing a highly dynamic ice sheet during both the most intense growth and recession phases.

Recrystallization of high-purity aluminium during equal channel angular pressing

Aluminium with 5N purity were deformed at room temperature by equal channel angular pressing following Route A up to three passes. The microstructure and the crystallographic texture were investigated by orientation imaging microscopy and electron backscatter diffraction, respectively. The microstructure showed complete recrystallization after the first ECAP pass onwards. The grain size decreased slightly with increasing number of passes. The corresponding texture consisted of an oblique cube component. The oblate grains and the cube texture were rotated anticlockwise about the transverse direction. The inclination of grains with respect to the direction of ECAP was dependent on the distance from the top of the billet and changed from pass to pass. The mechanism of formation of the microstructure and texture is discussed in the light of the physical phenomena involved.

Indigenized conceptual and empirical analyses of selected Chinese psychological characteristics

An academic movement to switch from Westernized Chinese psychology to an indigenized Chinese psychology in Chinese societies (Taiwan, Hong Kong, and China) has existed for about three decades. Indigenous‐oriented Chinese psychologists have conducted serious indigenized research on about 50 different broad topics. Kuo‐Shu Yang's conceptual and empirical analyses on 3 of them are briefly reviewed in this article: (a) Chinese familism, familization and pan‐familism; (b) Chinese psychological traditionality and modernity; and (c) theoretical and empirical analyses of the Chinese self. On the first topic, an indigenized conceptual scheme for the psychological components of Chinese familism at the cognitive, affective, and intentional levels was proposed. On the basis of the framework, standardized familism scales were constructed and used to study the relationships among the major components at each psychological level, using Taiwan students and adults as participants. In addition, the process of familization, an important aspect of Chinese familism, and its ability to form pan‐familism in outside‐family organizations, is briefly analysed. On the second topic, Yang empirically found that Chinese psychological traditionality (T) and modernity (M) were two independent psychological syndromes, each with five factor‐analytically identifiable oblique components. Two separate standardized assessment tools were developed and applied in various empirical studies involving T and M. One study revealed that most T factors only negligibly correlated with most M factors, indicating a general trend for the two sets of components to coexist with each other during the process of societal modernization. Finally, on the third topic, Yang developed a four‐part theory of the Chinese self from an indigenized perspective, based upon his conception of social vs individual orientation. The theory proposed that the Chinese self is composed of four self subsystems, viz., individual‐, relationship‐, familistic(group)‐, and other‐oriented selves, differing from each other in many respects. Yang and associates have conducted a series of empirical studies to examine a number of testable hypotheses derived from the theory. Findings from these studies are basically supportive.

Dependence of Illusory Motion on Directional Consistency in Oblique Components

Pinna and Brelstaff (2000 Vision Research 40 2091-2096) reported a motion illusion on viewing two concentric circles consisting of quadrangular components with black and white sides on a grey background. Our results suggest that the illusion is based on the integration of motion signals derived from oblique components, and on the consistency in the direction among those components. Furthermore, arrays of these oblique components can elicit the perception of motion not only for the oblique components themselves, but also for other objects in the picture. We propose that the motion illusion depends not only upon detection of the illusory motion signal at each local oblique component, but also upon the accumulation of the signal all over the stimulus configuration.

Effect of inertia on film flow over oblique and three-dimensional corrugations

The gravity-driven flow of a liquid film down an inclined plane wall with small-amplitude two-dimensional oblique or three-dimensional doubly periodic corrugations is investigated for finite Reynolds numbers. The film surface may exhibit constant or variable surface tension due to an insoluble surfactant. The key idea is to express the wall geometry as a Fourier series, and then reconstruct the three-dimensional flow in terms of the individual two-dimensional transverse and unidirectional flows over the constituent oblique two-dimensional corrugations. Three-dimensional corrugations may either reduce or amplify the surface deformation with respect to their two-dimensional counterparts due to the simultaneous effect of the constituent oblique components on the effective wave number, capillary number, and Reynolds number.

Plio-Pleistocene Ice Volume, Antarctic Climate, and the Global δ 18 O Record

We propose that from approximately 3 to 1 million years ago, ice volume changes occurred in both the Northern and Southern Hemispheres, each controlled by local summer insolation. Because Earth's orbital precession is out of phase between hemispheres, 23,000-year changes in ice volume in each hemisphere cancel out in globally integrated proxies such as ocean delta18O or sea level, leaving the in-phase obliquity (41,000 years) component of insolation to dominate those records. Only a modest ice mass change in Antarctica is required to effectively cancel out a much larger northern ice volume signal. At the mid-Pleistocene transition, we propose that marine-based ice sheet margins replaced terrestrial ice margins around the perimeter of East Antarctica, resulting in a shift to in-phase behavior of northern and southern ice sheets as well as the strengthening of 23,000-year cyclicity in the marine delta18O record.

SCALE MODEL TESTS OF A FISHING VESSEL IN ROLL MOTION PARAMETRIC RESONANCE

This paper presents a description and some experimental results concerning the problem of parametric destabilization and roll motion resonant oscillation of ship moving in longitudinal encountering waves. This induced roll motion of a ship is of interest since it appears when moving in longitudinal waves, despite the fact that there is not any other oblique wave component to directly excite the transverse oscillation and the crew is not waiting anything like that in such a short time. The experiments were carried out on a reduced scale model of a small fishing vessel tested at the Naval Hydrodynamic Laboratory, Austral University of Chile * . The results show how those longitudinal encountering waves can develop big roll motion angles in a short time.

An Anatomical and Electrophysiological Study of Vastus Medialis - How Distinct Is its Distal Oblique Component?

An Anatomical and Electrophysiological Study of Vastus Medialis - How Distinct Is its Distal Oblique Component?

Changes in Corneal Power and Refraction Due to Sequential Suture Removal Following Nonmechanical Penetrating Keratoplasty in Eyes With Keratoconus

To assess the changes in corneal power and refraction due to sequential suture removal after penetrating keratoplasty (PK). Retrospective consecutive case series. setting: Clinical practice. study population: We studied 67 phakic keratoconus eyes (central excimer laser trephination, primary keratoplasty, graft/recipient diameter 8.1/8.0 mm; double running suture) in this longitudinal study. main outcome measures: Zeiss keratometry (equivalent power (KEQ), astigmatism (KAST)), corneal topography (equivalent power (TEQ), astigmatism (TAST)) and subjective refractometry (spherical equivalent (SEQ), refractive cylinder (RAST)) were assessed with sutures in place (interval 1), with one suture out (interval 2), and with all sutures out (interval 3). observation procedure: Corneal power and refraction was decomposed into vector components and the changes were derived between time stages. The mean follow-up period was 3.9+/-1.7 years. At interval 1, the axes of KAST/TAST/RAST were almost randomly distributed. At interval 2, the with/against the rule component of KAST/TAST/RAST decreased slightly and the oblique component increased significantly, so that the axes tended to have a preferred oblique direction. At interval 3, the with/against the rule component of KAST/TAST/RAST increased slightly and the oblique component decreased significantly, so that the with/against the rule component exceeded the oblique component by approximately 23%/28%/25%. Median KEQ/TEQ/SEQ changed by 0.64/0.62/-1.11 diopters (interval 1 to interval 2) and by -0.85/-0.90/1.56 diopters (interval 2 to interval 3). As a result of removal of the first running suture, corneal astigmatism as well as the refractive cylinder tend to oblique axes. As a result of removal of the second running suture, the final corneal astigmatism and refractive cylinder tend to orientation axes with/against the rule.

Interaction between normal faults and pre-existing thrust systems in analogue models

Abstract The influence of pre-existing thrusts on the development of later normal faults was investigated using scaled laboratory analogue models. Experiments consisted of a phase of shortening followed by extension at variable angles of obliquity (α) to the shortening direction. Results suggest that the angle α has a major influence on the surface fault pattern and on the interaction between shortening-related structures and later extensional structures. Three different modes of interactions were identified depending upon the extension kinematics. (1) For orthogonal extension (α = 0°), shortening-related fold and thrust structures strongly influence the development of normal faults: graben structures nucleate within anticlines and the normal faults reactivate thrusts at depth ( branching at depth mode of interaction ). (2) For highly oblique extension (α ≥ 45°), shortening-related structures exert no influence on normal faults as extension-related steeply-dipping faults (characterized by an oblique component of movement) displace early thrusts ( no interaction mode ). (3) For intermediate obliquity angles (α = 15°, 30°), an intermediate mode of interaction characterizes the experiments, where the no interaction and branching at depth modes coexist in different regions of models. Modelling results can be used to infer regional extension directions as is shown for the Northern Appenines (Italy).

Experimental and simulated angular profiles of fluorescence and diffuse reflectance emission from turbid media

Given the wavelength dependence of sample optical properties and the selective sampling of surface emission angles by noncontact imaging systems, differences in angular profiles due to excitation angle and optical properties can distort relative emission intensities acquired at different wavelengths. To investigate this potentiality, angular profiles of diffuse reflectance and fluorescence emission from turbid media were evaluated experimentally and by Monte Carlo simulation for a range of incident excitation angles and sample optical properties. For emission collected within the limits of a semi-infinite excitation region, normalized angular emission profiles are symmetric, roughly Lambertian, and only weakly dependent on sample optical properties for fluorescence at all excitation angles and for diffuse reflectance at small excitation angles relative to the surface normal. Fluorescence and diffuse reflectance within the emission plane orthogonal to the oblique component of the excitation also possess this symmetric form. Diffuse reflectance within the incidence plane is biased away from the excitation source for large excitation angles. The degree of bias depends on the scattering anisotropy and albedo of the sample and results from the correlation between photon directions upon entrance and emission. Given the strong dependence of the diffuse reflectance angular emission profile shape on incident excitation angle and sample optical properties, excitation and collection geometry has the potential to induce distortions within diffuse reflectance spectra unrelated to tissue characteristics.