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The simultaneous increase in strength and plasticity of aluminum and its alloys at cryogenic temperatures has been shown in previous research, but the deformation mechanism was still unclear. Therefore, the purpose of this investigation was to reveal the relationship between slip behavior and mechanical response at low temperatures. A quasi-in situ scanning electron microscope was used to observe the evolution of slip bands in the selected aluminum single crystals with two typical orientations at 25 °C, −100 °C, and −180 °C. The results showed that irrespective of orientation, the density of the slip plane was increased with the decline in temperature, which inhibited slip localization and significantly improved plasticity and work hardening. In detail, at RT, the slip bands were widening until the micro-cracks were generated, causing early failure during deformation. When the temperature was decreased to −180 °C, the slip plane density was increased, and the deformation was more homogenous. Moreover, the slip mode was influenced by orientation and temperature. In particular, a single slip system was activated in the sample with the [112] orientation at all the temperatures investigated. Multiple slip systems were found to activate at 25 °C and −100 °C, and only the primary slip system was activated in the sample with [114] orientation at −180 °C. These findings deepen the understanding of slip behavior at cryogenic temperatures, providing new insights into the deformation mechanism of aluminum and its alloys. [ABSTRACT FROM AUTHOR]

This review aims to provide a literature overview as well as the authors' personal account to the studies of Laponite® (Lap)/Polyethylene‐oxide (PEO) based composite materials and their applications. These composites can be prepared over a wide range of their mutual concentrations, they are highly water soluble, and have many useful physico‐chemical properties. To the readers' convenience, the contents are subdivided into different sections, related with consideration of PEO properties and its solubility in water, behavior of Lap systems(structure of Lap‐platelets, properties of aqueous dispersions of Lap and aging effects in them), analyzing ofproperties LAP/PEO systems, Lap platelets‐PEO interactions, adsorption mechanisms, aging effects, aggregation and electrokinetic properties. The different applications of Lap/PEO composites are reviewed. These applications include Lap/PEO based electrolytes for lithium polymer batteries, electrospun nanofibers, environmental, biomedical and biotechnology engineering. Both Lap and PEO are highly biocompatible with living systems and they are non‐toxic, non‐yellowing, and non‐inflammable. Medical applications of Lap/PEO composites in bio‐sensing, tissue engineering, drug delivery, cell proliferation, and wound dressings are also discussed. [ABSTRACT FROM AUTHOR]

Discrete dislocation dynamics (DDD) simulations reveal the evolution of dislocation structures and the interaction of dislocations. This study investigated the compression behavior of single-crystal copper micropillars using few-shot machine learning with data provided by DDD simulations. Two types of features are considered: external features comprising specimen size and loading orientation and internal features involving dislocation source length, Schmid factor, the orientation of the most easily activated dislocations and their distance from the free boundary. The yielding stress and stress-strain curves of single-crystal copper micropillar are predicted well by incorporating both external and internal features of the sample as separate or combined inputs. It is found that the machine learning accuracy predictions for single-crystal micropillar compression can be improved by incorporating easily activated dislocation features with external features. However, the effect of easily activated dislocation on yielding is less important compared to the effects of specimen size and Schmid factor which includes information of orientation but becomes more evident in small-sized micropillars. Overall, incorporating internal features, especially the information of most easily activated dislocations, improves predictive capabilities across diverse sample sizes and orientations.

It is considerably harder to generalize identity across different pictures of unfamiliar faces, compared with familiar faces. This finding hints strongly at qualitatively distinct processing of unfamiliar face stimuli—for which we have less expertise. Yet, the extent to which face selective versus generic visual processes drive outcomes during this task has yet to be determined. To explore the relative contributions of each, we contrasted performance on a version of the popular Telling Faces Together unfamiliar face matching task, implemented in both upright and inverted orientations. Furthermore, we included different age groups (132 British children ages 6 to 11 years [69.7% White], plus 37 British White adults) to investigate how participants' experience with faces as a category influences their selective utilization of specialized processes for unfamiliar faces. Results revealed that unfamiliar face matching is highly orientation-selective. Accuracy was higher for upright compared with inverted faces from 6 years of age, which is consistent with selective utilization of specialized processes for upright versus inverted unfamiliar faces during this task. The effect of stimulus orientation did not interact significantly with age, and there was no graded increase in the magnitude of inversion effects observed across childhood. Still, a numerically larger inversion effect in adults compared to children provides a degree of support for developmental changes in these specialized face abilities with increasing age/experience. Differences in the pattern of errors across age groups are also consistent with a qualitative shift in unfamiliar face processing that occurs some time after 11 years of age. Public Significance Statement: This study supports a contribution of specialized processing mechanisms for unfamiliar face processing that operate selectively for faces presented upright, compared to inverted in a similar manner to those seen for familiar faces. Observed orientation effects did not increase between 6 and 11 years of age, but were much stronger in adults, which provides a degree of support for developmental changes in specialized unfamiliar face abilities with increasing age/experience. [ABSTRACT FROM AUTHOR]

Two-photon absorption has been systematically studied in Ca3(VO4)2 and Ca2.7Sr0.3(VO4)2 crystals, both of which are prospective nonlinear optical and laser host materials. A strong dependence of the two-photon absorption coefficients on the orientation of the laser beam polarization with respect to the optical c-axis of the crystals is revealed. The measured coefficients for perpendicular and parallel orientations were 50 ± 10 cm/TW and 19 ± 4 cm/TW in Ca3(VO4)2, and 18 ± 3 cm/TW and 10 ± 2 cm/TW in Ca2.7Sr0.3(VO4)2, respectively. Thus, to minimize optical losses caused by two-photon absorption, an orientation of Ca2.7Sr0.3(VO4)2 crystals with the laser beam polarization parallel to the crystal optical c-axis is preferred. [ABSTRACT FROM AUTHOR]

Raman spectroscopy is widely used to examine the carbonate content within bone apatite, but Raman spectra are also sensitive to orientation effects between the polarisation of the incoming laser light and the sample orientation. This may lead to discrepancies when using Raman spectroscopy to evaluate the carbonate content as the extent of crystal organisation can change depending on the type of bone, age, and presence of mineralisation disorders in the organism. It is experimentally very challenging to evaluate the effect of orientation using individual bone crystals. Therefore, we have used density functional theory to examine the effect of orientation in apatitic materials. We examined hydroxyapatite and three different types of carbonated apatite: A‐type where the carbonate ion substitutes the two OH groups in the unit cell, B‐type where co‐substitution occurs between carbonate in a phosphate position and Na+ for Ca2+ to maintain charge balance, and AB‐type where carbonate sits in both A‐site and B‐site. Our simulations show that the OH group in hydroxyapatite has a strong orientation dependence, consistent with previous literature. In addition, the phosphate and carbonate bands of the apatitic structures are predicted to be orientation dependent, where the maximum scattering efficiency occurs in configurations in which the laser polarisation is parallel to the crystallographic axes of the material. The intensity changes of the phosphate and carbonate bands are not consistent upon changing orientations and thus may lead to an underestimation of carbonate contents if insufficient sampling points are used during bone analysis. [ABSTRACT FROM AUTHOR]

Recent studies have reported functional MRI (fMRI) activation within cerebral white matter (WM) using blood-oxygenation-level-dependent (BOLD) contrast. Many blood vessels in WM run parallel to the fibre bundles, and other studies observed dependence of susceptibility contrast-based measures of blood volume on the local orientation of the fibre bundles relative to the magnetic field or B0 axis. Motivated by this, we characterized the dependence of gradient-echo BOLD fMRI on fibre orientation (estimated by the local diffusion tensor) relative to the B0 axis to test whether the alignment between bundles and vessels imparts an orientation dependence on resting-state BOLD fluctuations in the WM. We found that the baseline signal level of the T2*-weighted data is 11% higher in voxels containing fibres parallel to B0 than those containing perpendicular fibres, consistent with a static influence of either fibre or vessel orientation on local T2* values. We also found that BOLD fluctuations in most bundles exhibit orientation effects expected from oxygenation changes, with larger amplitudes from voxels containing perpendicular fibres. Different magnitudes of this orientation effect were observed across the major WM bundles, with inferior fasciculus, corpus callosum and optic radiation exhibiting 14–19% higher fluctuations in voxels containing perpendicular compared to parallel fibres. [ABSTRACT FROM AUTHOR]

We present a generalization of a scalar nonlinear damage rheology model of a brittle solid to the case of a tensor damage parameter. The main values of damage tensor describe the reduction in the cross-sectional area of the material in three orthogonal directions. The introduced damage tensor allows decribing the orthotropy of the elastic properties of the material caused by the development of microfractures during the deformation. For the case of traditional triaxial compression, two general problems are considered: the orientation of damage (microfractures) in the entire material and the orientation of the localized damage zone, ensuring the maximum rate of its growth. The solution of the first problem shows that, the degree of disorientation of the original fracturing and the growth rate of new fracturing depend on the damage anisotropy parameter. The solution of the second problem demonstrates that the optimal angle of inclination of the localized damage zone is the Mohr-Coulomb angle with microfractures inside the zone oriented either strictly vertically or at an angle close to the Mohr-Coulomb angle. [ABSTRACT FROM AUTHOR]

Two-photon absorption has been systematically studied in Ca3(VO4)2 and Ca2.7Sr0.3(VO4)2 crystals, both of which are prospective nonlinear optical and laser host materials. A strong dependence of the two-photon absorption coefficients on the orientation of the laser beam polarization with respect to the optical c-axis of the crystals is revealed. The measured coefficients for perpendicular and parallel orientations were 50 ± 10 cm/TW and 19 ± 4 cm/TW in Ca3(VO4)2, and 18 ± 3 cm/TW and 10 ± 2 cm/TW in Ca2.7Sr0.3(VO4)2, respectively. Thus, to minimize optical losses caused by two-photon absorption, an orientation of Ca2.7Sr0.3(VO4)2 crystals with the laser beam polarization parallel to the crystal optical c-axis is preferred.

• Orientation & coating uniformity effects on bloodstained fabrics using DRIFTS. • Limits of detection determined for blood dilution on forensically relevant fabrics. • Detection limits decreased significantly by controlling for orientation of samples. • Natural variations in blood spectra acquired from non-uniform circumstances. • LOD for fabric found to be ~200× diluted blood under controlled conditions. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to analyze four types of forensically relevant fabrics coated with varying dilutions of blood. The blood was applied in two manners, dip coating with a smooth and uniform layer and drip coating with droplets from pipettes. Spectra of neat and dip coated fabrics were acquired using controlled orientations, and these were compared to spectra collected on samples with random orientations. The improved reproducibility seen in visual inspection of the spectra is confirmed by principal component and linear discriminant projections of the spectra, as well as by statistical hypothesis testing. Principal component regression (PCR), using the regions of the IR spectra associated with the amide A/B, I, II, and III vibrational bands (3500–2800, 1650, 1540, and 1350 cm−1), was employed on the more uniform dip coated spectra to estimate limits of detection for blood on two of the four fabrics – acrylic and nylon. These results demonstrate that detection limits for blood on fabrics can be decreased significantly by controlling for the orientation and face of the fabric samples while collecting spectra. Limits of detection for acrylic and nylon were found to be 196 × and 227 × diluted blood, respectively. [ABSTRACT FROM AUTHOR]

[Display omitted] The crystal plasticity finite element method (CPFEM) is a widely used technique for resolving macroscopic stress and strain onto the physically relevant length scales of grains and slip systems in ductile crystalline materials like structural metals. Here, the calibration of a CPFEM model for single crystal applications was found to depend critically on loading orientation, with an effect significant even at an angle of 0.1˚. Slight misorientation from high symmetry loading affected lattice rotation during tensile deformation, changing the number of active slip systems, and, as a result, the overall stress–strain behavior. The strongest misorientation effects occurred around the multi-slip orientations of [0 0 1], [1 1 1], [1 0 1], and [1 0 2], while the single slip orientation of [2 1 3] showed a negligible effect, as expected, and the double slip orientation of [1 1 2] showed less of an effect than [1 0 2] due to its relative lattice orientation stability. The magnitude of the misorientation effect increased dramatically with the strength of slip system interaction, which, in the chosen hardening framework, is represented by the latent hardening coefficient. In a case study on [0 0 1] Cu, offsets of 0.3–2.0˚ gave stress values at an engineering strain of 0.25 that were lower by 15–18% relative to the direct loading values, highlighting the importance of exact orientations for single crystal plasticity parameterization and application. [ABSTRACT FROM AUTHOR]

The effect of orientation on the laminar natural convection heat transfer from branching fins attached to a rectangular plate has been numerically investigated. The orientations are termed 'vBvF' (vertical Base vertical Fin) and 'hBvF' (horizontal Base vertical Fin) when the base plate is vertical and horizontal respectively and the branching fins are attached orthogonally on the base plate. The third orientation is 'vBhF' (vertical Base horizontal Fin) when the fins are arranged horizontally on a vertical base plate. Besides orientation effect, the investigation also involves the effect of fin dimensions on the heat dissipation performance. Optimum branching angle of a 'single' branching fin is determined in each orientation. Fin size influences the optimum angle only in hBvF orientation. By studying the characteristics of buoyant fluid flow over the heat sinks, we have observed 'vortex motion', 'geometry induced acceleration' for certain sizes and orientations of the fins. These flow features are specific to the branching fins in natural convection. The dependency of the average heat transfer coefficient on the fin dimensions is explained and correlations to predict the Nusselt number in terms of non-dimensional parameters are developed. Highest thermal performance is obtained in vBvF orientation followed by hBvF and vBhF orientations. A comparison test has indicated that the branching fins have more effectiveness and efficiency than rectangular fins of equal mass and equal base area in all orientations. [ABSTRACT FROM AUTHOR]

Functional magnetic resonance imaging (fMRI) is now capable of sub-millimetre scale measurements over the entire human brain, however with such high resolutions each voxel is influenced by the local fine-scale details of the cerebral cortical vascular anatomy. The cortical vasculature is structured with the pial vessels lying tangentially along the grey matter surface, intracortical diving arterioles and ascending venules running perpendicularly to the surface, and a randomly oriented capillary network within the parenchyma. It is well-known that the amplitude of the blood-oxygenation level dependent (BOLD) signal emanating from a vessel depends on its orientation relative to the B 0 -field. Thus the vascular geometric hierarchy will impart an orientation dependence to the BOLD signal amplitudes and amplitude differences due to orientation differences constitute a bias for interpreting neuronal activity. Here, we demonstrate a clear effect of cortical orientation to B 0 in the resting-state BOLD-fMRI amplitude (quantified as the coefficient of temporal signal variation) for 1.1 mm isotropic data at 7T and 2 mm isotropic at 3T. The maximum bias, i.e. the fluctuation amplitude difference between regions where cortex is perpendicular to vs. parallel to B 0 , is about + 70 % at the pial surface at 7T and + 11 % at 3T. The B 0 orientation bias declines with cortical depth, becomes progressively smaller closer to the white matter surface, but then increases again to a local maximum within the white matter just beneath the cortical grey matter, suggesting a distinct tangential network of white matter vessels that also generate a BOLD orientation effect. We further found significant (negative) biases with the cortex orientation to the anterior-posterior anatomical axis of the head: a maximum negative bias of about − 30 % at the pial surface at 7T and about − 13 % at 3T. The amount of signal variance explained by the low frequency drift, motion and the respiratory cycle also showed a cortical orientation dependence; only the cardiac cycle induced signal variance was independent of cortical orientation, suggesting that the cardiac induced component of the image time-series fluctuations is not related to a significant change in susceptibility. Although these orientation effects represent a signal bias, and are likely to be a nuisance in high-resolution analyses, they may help characterize the vascular influences on candidate fMRI acquisitions and, thereby, may be exploited to improve the neuronal specificity of fMRI. • The BOLD rs-fMRI fluctuation amplitude depends on cortical orientation to B0. • Perpendicular vs. parallel orientation induces up to 70% signal bias in 1.1 mm isotropic 7T data. • Perpendicular vs. parallel orientation induces up to 11% signal bias in 2 mm isotropic 3T data. • BOLD orientation effects exist below the GM-WM border, implying vascular influence in WM. [ABSTRACT FROM AUTHOR]

Highlights • Experiments investigate pressure and temperature oscillations in flow condensation. • Amplitude of oscillations evaluated for vertical and horizontal orientations. • Flow regimes identified for the different orientations. • Key differences seen when comparing results across orientations. • Recent flow regime maps evaluated for predictive accuracy. Abstract While many prior works in the field relied upon direct optical access to determine condensation flow regimes, the present work outlines a new methodology utilizing temperature and pressure measurements to identify condensation flow regimes. For vertical upflow condensation, amplitude of dynamic temperature and pressure oscillations are shown to clearly indicate transition from counter-current flow regimes (i.e., falling film , oscillating film , flooding) to annular, co-current flow (climbing film flow regime). In horizontal flow condensation, standard deviation between multiple thermocouple measurements distributed around the tube circumference was calculated at all axial (stream-wise) measurement locations. High values of standard deviation are present for stratified flow (stratified flow, wavy-stratified, plug flow), while axisymmetric flow regimes (i.e., slug flow , annular flow) yield significantly lower values. Successful development of this technique represents a valuable contribution to literature as it allows condensation flow regime to be identified without the often-costly restriction of designing a test section to allow optical access. Identified flow regimes in both vertical upflow and horizontal flow orientations are compared to regime maps commonly found in the literature in pursuit of optimum performing maps. [ABSTRACT FROM AUTHOR]

Refractory multi-principal element alloys (RMPEAs) are promising candidate materials for use in high temperature structural applications and other extreme environments. Recent experiments and simulations have highlighted the unusual deformation behavior of an equiatomic MoNbTi alloy, which exhibits slip on higher order planes and sluggish edge dislocation mobility. In this work, we utilize micropillar compression and postmortem transmission electron microscopy to elucidate the orientation dependent deformation behavior of MoNbTi. Our results suggest that deformation in this system is largely mediated by kink-migration of screw dislocations, as evidenced by the presence of long screw dislocations and significant dislocation debris in postmortem observations, and the absence of twinning/anti-twinning asymmetry. Moreover, we report an unusual orientation dependence of the yield strength, owing to the high stress required to facilitate slip on {110} type planes. These results further demonstrate the unconventional plasticity in BCC RMPEAs, and provide experimental verification that kink-migration is the rate limiting feature in this alloy at low temperatures. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper is the second part of a two-part study on pool boiling critical heat flux (CHF) from flat surfaces. While the first part reviewed different CHF models and associated mechanisms and parametric trends, the present part is dedicated to the assessment of both models and correlations. The assessment is based on a new consolidated CHF database consisting of 800 data points amassed from 37 sources, and includes 14 working fluids, pressures from 0.0016 to 5.2 MPa, orientation angles from 0 to 180°, and contact angles from 0 to 113°. It is shown that a modified hydrodynamic instability model and the interfacial lift-off model provide the best predictions for CHF from horizontal, upward-facing surfaces. Modified with a correlation for surface orientation effects, the same models also provide the best predictions for inclined surfaces. However, all models and correlations lose accuracy at or near the downward-facing orientation, which points to the need for more data and improved understanding of near-wall interfacial behavior for these orientations. Finally, recommendations are provided for prediction of contact angle effects. [ABSTRACT FROM AUTHOR]

Body force effects in flow condensation vary depending on channel orientation and fluid mass velocity, making the design of systems intended to operate in multiple orientations more complicated than those at a fixed orientation. This study examines the effects of body force on liquid film development for flow condensation of FC-72 in horizontal, vertical upflow, and vertical downflow orientations. Two test sections are utilized, one capable of providing high-speed imaging of liquid film development, and the other designed to allow detailed measurements of flow condensation heat transfer coefficient. High speed imaging shows that for low FC-72 mass velocities, flow regimes differ significantly among the three orientations, with vertical upflow exhibiting falling film behavior, horizontal flow showing stratification, and vertical downflow displaying annular co-current flow. For the case of low mass velocity horizontal flow, interfacial disturbances in the form of a sinusoidal wave are clearly visible with wavelengths on the order of 1–10 mm. As mass velocity is increased, the liquid film is seen to exhibit similar behavior for all three orientations due to interfacial shear stress negating body force effects. Heat transfer measurements reinforce these trends, with circumferential variations in heat transfer coefficient present for horizontal flow at low mass velocities, and differences in the axial variations in heat transfer coefficient seen when comparing vertical upflow to vertical downflow. As mass velocity is increased, differences in heat transfer coefficient are reduced, with the highest mass velocities exhibiting almost no variation with orientation. This convergence of values indicates the ability of interfacial shear stress to mitigate body force effects at sufficiently high mass velocities. [ABSTRACT FROM AUTHOR]

This study concerns the development of a set of mechanistic criteria capable of predicting the flow conditions for which gravity independent flow condensation heat transfer can be achieved. Using FC-72 as working fluid, a control-volume based annular flow model is solved numerically to provide information regarding the magnitude of different forces acting on the liquid film and identify which forces are dominant for different flow conditions. Separating the influence of body force into two components, one parallel to flow direction and one perpendicular, conclusions drawn from the force term comparison are used to model limiting cases, which are interpreted as transition points for gravity independence. Experimental results for vertical upflow, vertical downflow, and horizontal flow condensation heat transfer coefficients are presented, and show that, for the given test section, mass velocities above 425 kg/m 2 s ensure gravity independent heat transfer. Parametric evaluation of the criteria using different assumed values of mass velocity, orientation, local acceleration, and exit quality show that the criteria obey physically verifiable trends in line with those exhibited by the experimental results. As an extension, the separated flow model is utilized to provide a more sophisticated approach to determining whether a given configuration will perform independent of gravity. Results from the model show good qualitative agreement with experimental results. Additionally, analysis of trends indicate use of the separated flow model captures physics missed by simpler approaches, demonstrating that use of the separated flow model with the gravity independence criteria constitute a powerful predictive tool for engineers concerned with ensuring gravity independent flow condensation heat transfer performance. [ABSTRACT FROM AUTHOR]

This study explores the influence of a 316 L stainless steel substrate on growth of CoCrFeMnNi coatings deposited using magnetron sputtering at different substrate bias. The study was carried out on a polycrystalline 316 L substrate where the growth behavior of the coating could be investigated on grains with different orientations. By combining electron backscatter diffraction (EBSD) before and after deposition and characterization of the same area, it was possible to determine growth behavior and surface morphologies on individual substrate grains. No strong influence of the substrate was observed at a floating bias. At a bias of -100 V, however, the coating was strongly influenced by the orientation of the individual substrate grains. Epitaxial growth with a smooth coating grain surface was observed on the <102>-oriented grains while a more columnar growth was observed on <111>-oriented substrate grains. Furthermore, a small difference in growth rate was observed on different substrate orientations. The growth behavior could be related to differences in energy transfer from incoming ions and diffusion rates during growth on different orientations. • EBSD was used to investigate the influence of substrate grain orientations on the growth of CoCrFeMnNi coatings. • A strong relationship was observed between substrate grain and coating orientations. • A high density of twins was observed in the coating growing on <111> oriented substrate grains. • The substrate effect on the growth is partly attributed to variation in energy transfer on different surface orientations. [ABSTRACT FROM AUTHOR]

Lack of understanding of flow boiling behavior in reduced gravity poses a major challenge to the development of future space vehicles utilizing two-phase thermal control systems (TCSs). A cost effective method to investigating the influence of reduced gravity on flow boiling is to perform ground experiments at different orientations relative to Earth gravity. This paper is the first part of a two-part study aimed at exploring flow boiling mechanisms of FC-72 in a rectangular channel heated along one wall or two opposite walls. Experiments are performed in vertical upflow, vertical downflow and horizontal flow, subject to large variations in mass velocity, inlet quality and wall heat flux. Detailed measurements are used to investigate the influences of orientation, and therefore gravity, on boiling curve, local and average heat transfer coefficients, and pressure drop, and their relationship with interfacial behavior is captured with high-speed video. For horizontal flow, the effects of gravity are reflected in appreciable stratification across the channel at low mass velocities, with gravity aiding vapor removal from, and liquid return to the bottom heated wall, while accumulating vapor along the top heated wall. For vertical upflow and vertical downflow, with both single-sided and double-sided heating, there is far better symmetry in vapor formation along the channel. The heat transfer coefficient shows significant variations among the different orientations and heating configurations at low mass velocities, but becomes insensitive to orientation above 800 kg/m 2 s, proving inertia around this mass velocity is effective at negating any gravity effects. For low mass velocities, pressure drops are fairly equal for vertical upflow and vertical downflow, but greater than for horizontal flows. However, fairly equal pressure drops are achieved at high mass velocities for all orientations. Overall, this study proves that gravity effects on two-phase pressure drop and two-phase heat transfer are dictated mostly by mass velocity and, to a lesser extent, by inlet quality. [ABSTRACT FROM AUTHOR]

This study is the second part of a two-part study exploring flow boiling of FC-72 along a rectangular channel with either one wall or two opposite walls heated for saturated inlet conditions. While the first part examined flow boiling interfacial behavior, boiling curves, local and average heat transfer coefficients, and pressure drops, this part is focused entirely on CHF measurement, flow visualization and modeling. Both single-sided and double-sided heating configurations are tested in horizontal flow, vertical upflow, and vertical downflow. For low mass velocities, high speed video analysis shows gravity has a dominant influence on interfacial behavior, with single-sided top-wall heating yielding the lowest CHF values, and bottom-wall heating the highest. For both single-sided heating and double-sided heating, increasing mass velocity decreases the influence of orientation on CHF, with identical CHF values achieved at high mass velocities irrespective of orientation, and increasing inlet quality serves to decrease the mass velocity value required for inertia to completely overcome gravity effects. A separated flow model for two-phase inlet conditions is proposed to predict key flow variables necessary for CHF modeling. With a MAE ⩽ 14%, this study proves that the combination of separated flow model and Interfacial Lift-off Model is highly effective at predicting CHF for saturated inlet conditions as it did in prior studies for subcooled inlet conditions. [ABSTRACT FROM AUTHOR]

We investigated how twin modes in hexagonal close packed materials can affect large inelastic strain behavior and fracture. We considered the two twin mode systems of ( 11 2 ¯ 1 ) [ 1 ¯ 1 ¯ 26 ] and (0001) [ 1 ¯ 1 ¯ 20 ] in zircaloy-2, with each mode having 24 unique twin systems. We then incorporated these twin and parent slip systems with a dislocation-density crystalline plasticity, a non-linear finite-element, and fracture framework that accounts for crack nucleation and propagation. We investigated how these twin modes affect the interrelated effects of crack nucleation and propagation, dislocation density and inelastic slip evolution, stress accumulation, and lattice rotation. The predictions indicate that twin modes significantly affect local deformation and fracture behavior, and, therefore, are essential for the accurate representation of behavior at different physical scales in heterogeneous crystalline hexagonal close packed systems. [ABSTRACT FROM AUTHOR]

In this work, a continuum model is presented for size and orientation dependent thermal buckling and post-buckling of anisotropic nanoplates considering surface and bulk residual stresses. The model with von-Karman nonlinear strains and material cubic anisotropy of single crystals contains two parameters that reflect the orientation effects. Using Ritz method, closed form solutions are given for buckling temperature and post-buckling deflections. Regarding self-instability states of nanoplates and their recovering at higher temperatures, an experiment is discussed based on low pressurized membranes to verify the predictions. For simply supported nanoplates, the size effects are lowest when they are aligned in [100] direction. When the edges get clamped, the orientation dependence is ignorable and the behavior becomes symmetric about [510] axis. The surface residual stress makes drastic increase in buckling temperature of thinner nanoplates for which a minimum thickness is pointed to stay far from material softening at higher temperatures. Deflection of [100]-oriented buckled nanoplates is higher than [110] ones but this reverses at higher temperatures. The results for long nanoplates show that the buckling mode numbers are changed by orientation which is verified by FEM. [ABSTRACT FROM AUTHOR]

• This study investigates subcooled flow boiling in a rectangular channel at three flow orientations. • Databases from prior experiments are compiled into single consolidated database for two-phase heat transfer coefficient. • Prior seminal correlations for subcooled flow boiling are assessed for predictive performance. • A new correlation is proposed which is shown to outperform all prior seminal correlations. This study explores subcooled flow boiling of n-Perfluorohexane in a rectangular channel of 5.0 mm height, 2.5 mm width (heated), and 114.6 mm heated length. This Flow Boiling Module (FBM) is part of the Flow Boiling and Condensation Experiment (FBCE), which is a long-term collaborative effort to study the effects of gravity on flow boiling and condensation for their implementation in future space missions besides other applications. Datasets obtained from subcooled-inlet experiments performed using the FBM prior to its launch to the International Space Station (ISS) are examined and local subcooled flow boiling datapoints compiled to form a consolidated database. The consolidated 2589 datapoints cover broad ranges of operating conditions (mass velocity: 172.79 – 3200.00 kg/m2s, pressure: 102.16 – 238.44 kPa, subcooling: 0.13 – 34.93°C, quality: -0.560 – -0.000, heat flux: 1.80 – 49.99 W/cm2), flow orientations (vertical upflow, vertical downflow, and horizontal flow in Earth gravity), and partial heating configurations (single- and double-sided heating). Prior seminal correlations for subcooled flow boiling heat transfer are assessed for their predictive performance. Each local flow boiling curve is analyzed and manually demarcated into three regimes: partially developed boiling (PDB), fully developed boiling (FDB), and nucleate boiling degradation (NBD). A simple, yet very effective correlation based on dimensionless groups and having a fully explicit functional form, is developed. The new correlation well predicts both the subcooled flow PDB and FDB regimes with overall mean absolute errors (MAEs) of 9.59% and 6.91%, respectively. Although predictions for the NBD regime are much higher than observed with an overall MAE of 41.71%, they can be treated as upper limits to heat transfer here. The correlation is independent of both flow orientation and heating configuration. Overall, the new correlation clearly outperforms all prior seminal correlations for the entire consolidated database, with excellent predictions for both partially and fully developed subcooled flow boiling, i.e., for heat fluxes ranging from onset of nucleate boiling to onset of nucleate boiling degradation. [ABSTRACT FROM AUTHOR]

The objective of this study is to examine whether manipulating the orientation of a rating scale impacts on the perceived intensity of the verbal qualifiers. An experiment is designed to assess the perception of intensities of verbal qualifiers in an agreement scale. A first finding is that participants seem to adopt one of two response strategies. Those who show the ’extreme null-point strategy’ report perceived intensities that monotonically increase along with the scale from ’fully disagree’ to ’fully agree’. However, other respondents seem to adopt a ’middle null-point strategy’, where the highest perceived intensity coincides with both extreme qualifiers of the scale and the lowest intensity is experienced for qualifiers near the middle. An orientation effect is supported for the ’extreme null-point strategy’ group, and manifests itself in less agreement about the intensity of the qualifiers when placed on a decremental scale (e.g. fully agree - rather agree - neutral - rather disagree - fully disagree) as opposed to an incremental scale (e.g. fully disagree - rather disagree - neutral - rather agree - fully agree). Next, the existence of a primacy-effect, an orientation effect found in previous research, was tested by means of a web survey-experiment and is rejected in favour of a more differentiated effect.

Abstract: The nucleus–nucleus interaction potentials for the fusion reactions 16O+ 208Pb, 64Ni+ 64Ni, 58Ni+ 58Ni and 16O+ 154Sm are extracted from the improved isospin-dependent quantum molecular dynamics model. The shell correction effects are discussed. The negative shell correction energies lower potential barriers of a certain reaction. The incident energy dependence of the potential barrier is investigated for each system. A complex phenomenon of energy dependence is observed. It is also found that incident energy dependence of the barrier radius and barrier height shows opposite behaviors. The Coulomb potential shows weak energy dependence when distance of two colliding nuclei is lower than the touching distance. The isospin effects of the potential barrier are investigated. The orientation effects of the potential barrier is also discussed for the system 16O+ 154Sm. The fusion cross sections that correspond to the equatorial orientation of 154Sm are very low in sub-barrier region because of the high fusion barriers and the shallow potential pockets. [Copyright &y& Elsevier]

Abstract: We present a secondary ionization mass spectrometry (SIMS) technique for U–Pb geochronology of rutile at high spatial resolution and sensitivity using an O2 + primary ion beam coupled with surficial O2 gas deposition (O2 flooding). The O2 + beam is ~10× more intense than conventionally applied O− or O2 − beams at the same lateral resolution. Natural and synthetic rutile was determined to be conductive under O2 + bombardment, permitting higher excavation (sputter) rates than conventional SIMS using negatively charged O-beams without detrimental effects of sample charging. The main advantage of O2 + is rapid sputtering at shallow primary ion penetration depths. This minimizes the contribution of surface-derived common Pb, and generates a high secondary ion flux at high sensitivity with useful yields (UY=detected ions/atoms removed from target) for Pb in rutile of ~4 and 3% for O− and O2 +, respectively. In addition, O2 flooding reduces spread in the Pb+/U+ vs. UO2 +/U+ calibration by mitigating crystal orientation dependent variability of sputter yields. Calibrated against primary rutile standard R10b (1090Ma), O2 +-generated SIMS U–Pb and Pb–Pb age averages are accurate within <1% for Early Paleozoic to Archean rutile, without evidence for significant crystal orientation bias. We propose that O2 + bombardment can also be advantageous for SIMS analysis of other conductive minerals such as cassiterite, columbite–tantalite, hematite, ilmenite, and magnetite. [Copyright &y& Elsevier]

Abstract: Formability of four magnesium AZ31B sheet materials, produced either by direct chill or twin roll continuous casting, was investigated at 400°C and 5×10−3 s−1 using pneumatic stretching. Sheet specimens were deformed through a series of four elliptical die inserts, with aspect ratios ranging between 1.0 and 0.4, producing ellipsoidal domes with different biaxial strain combinations. Testing was carried out in two scenarios, i.e. with the major strains aligned either along or across the rolling direction of the material. Circle grid analysis was then used to map the planar strains of the deformed specimens; the latter were used to generate comprehensive material forming limits curves (FLCs) that bound the safe, marginal and failure deformation zones. Orientation effects were quantified by constructing a “composite FLD” for each of the four sheets; the diagrams collectively showed that greater formability limits are achieved along the material''s rolling direction. Furthermore, detailed comparisons between the four sheets were carried out based on formability limits, deformation uniformity, maximum dome height prior to failure, and fracture surface morphology and chemistry. Disparities in formability were linked to differences in grain structure and material inhomogeneities. [Copyright &y& Elsevier]

Abstract: In situ high precision U–Pb analysis of rutile by secondary ion mass spectrometry (SIMS) reveals that instrumental bias for isotope ratios and count rates vary due to crystal orientation. Electron backscatter diffraction (EBSD) techniques have been combined with SIMS data to show consistent and systematic crystal orientation effects, whilst confirming that all analyses are on single crystals and that there is random variation from grain to grain. The result of the orientation effect is to produce an extremely large calibration slope, more than an order of magnitude larger than for other minerals, which can result in highly inaccurate and spurious U–Pb ages from rutile if not taken into account. We present a large standard dataset to highlight this effect and show that by collecting good standard data, from grains in multiple orientations, these effects can be negated and accurate U–Pb SIMS data for rutile can be obtained using a standard calibration slope of ln(Pb+/U+) vs ln(UO2 +/UO+)=1.12. Examples from the Anantangiri region, Eastern Ghats, India are used to show the magnitude of these effects on the calibration of unknowns. Evidence is presented to show that the cause of these orientation effects is most likely a combination of channelling of primary ions into the crystal and preferential emission of secondary ions along preferred lattice directions. [Copyright &y& Elsevier]

The formability curves of AZ31B magnesium and 5083 aluminum alloy sheets were constructed using the pneumatic stretching test at two different sets of forming conditions. The test best resembles the conditions encountered in actual hydro/pneumatic forming operations, such as the superplastic forming (SPF) and quick plastic forming (QPF) techniques. Sheet samples were deformed at (400 °C and 1 x 10-3 s-1) and (450 °C and 5 x 10-3 s-1, by free pneumatic bulging into a set of progressive elliptical die inserts. The material in each of the formed domes was forced to undergo biaxial stretching at a specific strain ratio, which is simply controlled by the geometry (aspect ratio) of the selected die insert. Material deformation was quantified using circle grid analysis (CGA), and the recorded planar strains were used to construct the forming limit curves of the two alloys. The aforementioned was carried out with the sheet oriented either along or across the direction of major strains in order to establish the relationship between the material's rolling direction and the corresponding limiting strains. Great disparities in limiting strains were found in the two orientations for both alloys; hence, a "composite FLD" is introduced as an improved means for characterizing material formability limits. [ABSTRACT FROM AUTHOR]

The article presents a study that uses carbon K-edge X-ray spectroscopy to a wide range of organic samples specifically carbonate minerals. It mentions that the identification of such minerals in the samples can be accomplished through the pattern of resonances in the energy region. It affirms that the relative strengths of the carbonate resonances vary with crystal orientation to the polarized X-ray beam.

Abstract: Experiments were performed on natural convection heat transfer from circular pin fin heat sinks subject to the influence of its geometry, heat flux and orientation. The geometric dependence of heat dissipation from heat sinks of widely spaced solid and hollow/perforated circular pin fins with staggered combination, fitted into a heated base of fixed area is discussed. Over the tested range of Rayleigh number, 3.8×106 ≤Ra≤1.65×107 , it was found that the solid pin fin heat sink performance for upward and sideward orientations shows a competitive nature, depending on Rayleigh number and generally shows higher heat transfer coefficients than those of the perforated/hollow pin fin ones in both arrangement. For all tested hollow/perforated pin fin heat sinks, however, the performance for sideward facing orientation was better than that for upward facing orientation. This argument is supported by observing that the augmentation factor was around 1.05–1.11, depending on the hollow pin diameter ratio, Di/Do . Meanwhile, the heat sink of larger hollow pin diameter ratio, Di /Do offered higher heat transfer coefficient than that of smaller Di/Do for upward orientation, and the situation was reversed for sideward orientation. The heat transfer performance for heat sinks with hollow/perforated pin fins was better than that of solid pins. The temperature difference between the base plate and surrounding air of these heat sinks was less than that of solid pin one and improved with increasing Di/Do . [Copyright &y& Elsevier]

Abstract: The objective of this research was to generate zein ribbons on an extruder in which physical property analyses can be performed to determine whether physical properties were dependent on the testing direction. The extruded zein ribbon samples had between 10 and 15% triethylene glycol (TEG) and were conditioned at relative humidities between 23 and 70% before testing to determine the impact of sample testing direction on physical properties. Tensile strengths in the machine direction were between 18 and 64% higher than in the transverse direction. Elongations in the machine direction were between 33 and 291% higher than in the transverse direction. The magnitude of the difference between the machine and transverse direction was dependent on relative humidity and formulation. The impact of relative humidity was larger when the samples were tested in the machine direction; for example, tensile strength was reduced by 36% in the transverse direction and by 49% in the machine direction for the 15% TEG formulation when relative humidity was increased from 23 to 70%. With increased amounts of TEG, the magnitude of these differences was increased. The transverse direction tensile strength was reduced by 22% for a 10% TEG formulation, and by 36% for a 15% TEG formulation when relative humidity was increased from 23 to 70%. Polarized IR spectra of zein ribbons displayed differences between the spectra taken in the machine direction versus that taken in the transverse direction. Examination of the ribbons using polarizing light microscopy demonstrated that the ribbon was birefringent (δn=0.0004). These results demonstrate that molecular orientation occurred during extrusion and that orientation impacts physical properties. [Copyright &y& Elsevier]

Abstract: In situ atomic force microscopy is used to observe the structure and evolution of slip bands on the surface of plastically deformed aluminum single crystals. Both the structure and evolution of the slip bands are observed to be a function of the tensile axis. Near the [001] tensile axis, slip bands are observed to grow to a height of approximately 250nm over 2% plastic strain and then cease operation. Toward the stable [112] orientation, slip bands are observed to evolve continuously. Near the [111] tensile axis, wavy slip bands in which multiple systems are active in the same crystal region are observed. Other behavior, such as the operation of unpredicted slip systems, is also discussed. [Copyright &y& Elsevier]

Abstract: This paper presents the orientation effects on residual stress release by pulsed magnetic field treatment. Specimens are produced by tungsten inert gas (TIG) welding and the initial residual stresses in them are measured by the hole-drilling method. With different orientations these specimens are treated in the same magnetic field and the residual stresses are measured for the second time. By comparing the stress values before and after treatment it is obvious that magnetic field treatment effects are related to orientations. Based on a referred ferromagnetics formula, a supposition is proposed and a further survey of the magnetostriction constant is carried out. All experimental results support the proposed model and a prescription is given for pulsed magnetic field treatments. [Copyright &y& Elsevier]

Abstract: The ion scattering and sputtering processes at low energy grazing N+ and Ne+ ion bombardment of clean and oxygen covered Ag(110) surface have been investigated by computer simulation in the binary collision approximation. The spatial, angular and energy distributions of scattered, sputtered particles and desorbed molecules of oxygen as well as their yields versus the angle of incidence have been calculated. In these distributions the some characteristic peaks were observed and analysed. It was found that an adsorption layer plays a role of the additional surface barrier, i.e. it reflects leaving target atoms back to crystal. The azimuth angular dependencies of Ag sputtering yield and non-dissociative O2 desorption yield at grazing incidence have been calculated. It was shown that these dependencies correlate the crystal orientation. [Copyright &y& Elsevier]

Antibody 34E4 catalyzes the conversion of benzisoxazoles to salicylonitriles with high rates and multiple turnovers. The crystal structure of its complex with the benzimidazolium hapten at 2.5-Å resolution shows that a combination of hydrogen bonding, π stacking, and van der Waals interactions is exploited to position both the base, GluH50), and the substrate for efficient proton transfer. Suboptimal placement of the catalytic carboxylate, as observed in the 2.8-Å structure of the GluH50Asp variant results in substantially reduced catalytic efficiency. In addition to imposing high positional order on the transition state, the antibody pocket provides a highly structured microenvironment for the reaction in which the carboxylate base is activated through partial desolvation, and the highly polarizable transition state is stabilized by dispersion interactions with the aromatic residue TrpL91 and solvation of the leaving group oxygen by external water. The enzyme-like efficiency of general base catalysis in this system directly reflects the original hapten design, in which a charged guanidinium moiety was strategically used to elicit an accurately positioned functional group in an appropriate reaction environment and suggests that even larger catalytic effects may be achievable by extending this approach to the induction of acid- base pairs capable of bifunctional catalysis. [ABSTRACT FROM AUTHOR]

The spectral–angular distribution of the radiation of relativistic electrons in a crystal is very sensitive to the radiation mechanism. The results of an experimental research of the orientation effects in ultrarelativistic electron radiation in Si single crystals are presented in this work. The orientation dependences of the radiation angular distributions measured in the conditions of the axis effect manifestation are interpreted. The contribution of abovebarrier electrons in the radiation angle distribution is shown. The effect of “capture” of the radiation beam by crystal axis observed in the experiment has been explained by features of abovebarrier electron movement. [Copyright &y& Elsevier]

Bone, dentine and enamel samples were treated with a gas-propelled jet of an abrasive, NaHCO, which is physically much softer than any of these tissues in their fully mineralised condition. It was nevertheless found that they are all eroded by this treatment, which can therefore be used as a new kind of qualitative test of physical properties relating to wear resistance. General correlations were found between both degree of mineralisation and between structure orientation and erosion rate, surface-parallel-feature zones being worn more rapidly. Bone domains with surface-parallel collagen were eroded faster than those with perpendicular lamellae even if they were more densely mineralised. Rates of dentine wear depended on both density and tubule orientation, with peritubular zones and better mineralised incremental layers being more resistant. Enamel tufts wear more rapidly than the surrounding well mineralised regions. Enamel diazones wear less than parazones (areas with surface parallel prisms). At the prism scale, enamel is removed more rapidly near prism boundary discontinuities and in tubular enamel, at tubule walls. As regards the common orientation dependent effects seen in these three tissues, a cohesive explanation would be that structure discontinuities can be better exploited in a wear process if they allow cleavage from the surface; which tendency will increase with parallelism to the surface. [ABSTRACT FROM AUTHOR]

The growth of CdTe buffer layers on (211)B GaAs substrates by organometallic vapor phase epitaxy (OMVPE) was studied, and it was found that, depending on the growth conditions, either the (211) or (133) epitaxial orientation could be formed. In some cases, an epilayer showing a mixed (211) and (133) orientation was also observed. The influence of several growth parameters on the orientation of the CdTe layer was investigated, and it was found that the Te/Cd ratio, together with the growth temperature, have the most significant effect in determining the epilayer orientation. From these results, it was then possible to select nominally optimized growth conditions for CdTe buffer layers of both orientations. (Hg,Cd)Te layers of the same orientations could then be grown and characterized. Although double crystal x-ray diffraction measurements indicated a somewhat better crystalline perfection in the (133) (Hg,Cd)Te layers, these layers showed a poor surface morphology compared to the (211) orientation. Measurement of etch pit densities also indicated defect densities to be typically half an order of magnitude higher in the (133) orientation. Diodes were formed by ion implantation in both orientations and significantly better results were obtained on the (211) (Hg,Cd)Te layers. [ABSTRACT FROM AUTHOR]