Miracle-dz/UniFAR-FTUs huggingface dataset:
MECHANISM OF GRAIN REFINEMENT IN UNDERCOOLED CU30NI70

It was found that remelting is the origin of grain refinement in undercooled Cu30Ni70 specimens. It was also demonstrated that composition difference across a dendrite is the cause of remelting. The critical undercooling, ΔT* for grain refinement is 145 K for undercooledCu30Ni70.
Extended fluid models: Pressure tensor effects and equilibria

We consider the use of “extended fluid models” as a viable alternative to computationally demanding kinetic simulations in order to manage the global large scale evolution of a collisionless plasma while accounting for the main effects that come into play when spatial micro-scales of the order of the ion inertial scale di and of the thermal ion Larmor radius ϱi are formed. We present an extended two-fluid model that retains finite Larmor radius (FLR) corrections to the ion pressure tensor while electron inertia terms and heat fluxes are neglected. Within this model we calculate analytic FLR plasma equilibria in the presence of a shear flow and elucidate the role of the magnetic field asymmetry. Using a Hybrid Vlasov code, we show that these analytic equilibria offer a significant improvement with respect to conventional magnetohydrodynamic shear-flow equilibria when initializing kinetic simulations.
A heterogeneous system based on GPU and multi-core CPU for real-time fluid and rigid body simulation

Computational fluid dynamics in simulation has become an important field not only for physics and engineering areas but also for simulation, computer graphics, virtual reality and even video game development. Many efficient models have been developed over the years, but when many contact interactions must be processed, most models present difficulties or cannot achieve real-time results when executed. The advent of parallel computing has enabled the development of many strategies for accelerating the simulations. Our work proposes a new system which uses some successful algorithms already proposed, as well as a data structure organisation based on a heterogeneous architecture using CPUs and GPUs, in order to process the simulation of the interaction of fluids and rigid bodies. This successfully results in a two-way interaction between them and their surrounding objects. As far as we know, this is the first work that presents a computational collaborative environment which makes use of two different paradigms of hardware architecture for this specific kind of problem. Since our method achieves real-time results, it is suitable for virtual reality, simulation and video game fluid simulation problems.
Soldering to a single atomic layer

The standard technique to make electrical contact to nanostructures is electron beam lithography. This method has several drawbacks including complexity, cost, and sample contamination. We present a simple technique to cleanly solder submicron sized, Ohmic contacts to nanostructures. To demonstrate, we contact graphene, a single atomic layer of carbon, and investigate low- and high-bias electronic transport. We set lower bounds on the current carrying capacity of graphene. A simple model allows us to obtain device characteristics such as mobility, minimum conductance, and contact resistance.
Reduction of spurious resonance peaks in microcantilever tuning through substrate contact surface reduction

The tuning capabilities of otherwise similar tapping mode atomic force microscope (AFM) cantilever probes, for use in air, can be improved by patterning the backside of the respective probe substrate. Three designs were tested and rated against a standard unpatterned substrate. It was shown that lowering the probe substrate contact surface area decreased the occurrence of spurious resonance peaks and resulted in cleaner tuning curves as compared to probes with higher contact surface areas.
On the Mean Meridional Mass Motions of the Stratosphere and Mesosphere

Abstract Using a simplified, approximate “Lagrangian-mean” dynamical formulation, the mean meridional mass circulation of the stratosphere and mesosphere is discussed. Under solstice conditions, it is shown that this Lagrangian-mean circulation may be inferred, as a first approximation, from the Eulerian-mean diabatic heating. Diabatic heating rates for the solstices, originally derived by Murgatroyd and Goody (1958), result in Lagrangian-mean rising motion at the tropical tropopause, subsidence across the extratropical tropopause, and a very strong summer-to-winter pole flow in the mesosphere. This circulation is exactly that obtained by Murgatroyd and Singleton (1961) for the solstices. Those authors, however, attempted to identify this circulation as the Eulerian-mean motion, and were later criticized for their neglect of the meridional eddy heat flux in the calculation, which proved to be extremely important in the winter hemisphere. The present study, nevertheless, indicates that Murgatroyd and Singl.
Gas flows and the chemical evolution of galaxies - III. Graphical analysis and secondary elements

ABSTRA C T The general structure of the solutions of the chemical-evolution equations of a galaxy undergoing an arbitrary time-dependent accretion of metal-free gas is studied with graphical analysis. The behaviour is determined by the time evolution of the ratio a of accretion to star formation rate. This gives rise to two distinct regimes. (a) If a decreases monotonically with time, the properties are always between those predicted from the Simple Model and a Linear Accretion Model; the stellar mean metallicity and the abundance ratio of secondary and primary elements are thus restricted to a narrow range of a factor of 2. (b) Lower gas metallicities, larger secondary/primary ratios and stellar metallicities than expected from the Linear Accretion Models can only be reached if the accretion rate increases rapidly to a value larger than the star formation rate, e.g. by sudden massive accretion of gas into highly evolved gas-poor galaxies.
Modified temporal difference method for change detection

There is a tradeoff between effective and computational costs in traditional change detection methods. Reducing the computational cost of the processing time results in loss of quality of detection results. We propose a new change detection method based on the temporal difference principle. The new method combines the connected component labeling, closing operation of image morphology, and human structure analysis to remove shading and noise in consecutive frames. A closed object boundary and region can be extracted with only a small additional cost in processing times. Additionally, this new method recovers the disadvantages of traditional temporal difference methods. Comparative results, in terms of computational complexity, completeness of the object and the object's outline, robustness against noise and shadow, with currently popular methods and the proposed method are also displayed. The experimental results show that the proposed method is robust in varied illuminations and effective in several predefined environments for change detection.
The Life Cycle of a Thunderstorm in Three Dimensions

Abstract The results of an isolated three-dimensional thunderstorm simulation are reported. An initial wind shear of 1.54 m sec−1 km−1 is specified in the x direction and symmetry is assumed in the y direction about the central x-z plane. An erect cloud develops from an initial 3.7 km radius impulse as the updraft core is fed from all directions by moist and warm low-level air. After some time rain begins to fall and a downdraft developes downshear of the updraft core cutting off the major low-level supply of warm and moist air. Subsequently, the updraft core begins to tilt downshear and the center of the lower part of the updraft core is shifted away from the central x–z plane. At middle cloud levels wind features reminiscent of flow about a cylinder are present. Both the hydrostatic and dynamic pressure appear to be important in decelerating flow upwind of the cloud. Comparison with a similar two-dimensional simulation indicates that the three-dimensional cloud develops faster, grows taller, lasts longe.
Percolation and ripening in Si1-xGex/Si(001) islands: effect of misfit strain

We study the island size distributions of Xi1-xGex/Si(001) (x equals 0.4 - .07) islands of varying Ge fractions and thicknesses by ultrahigh vacuum chemical vapor deposition. The island size distributions of the percolating islands obey a dynamic scaling hypothesis admitting only one length scale governing the growth, in the limit of large island sizes. Although bimodal distributions are found in coherent islands at large misfit strain, due to the large stress concentration at island perimeters; faulted dislocation loops forming as islands grow remove this stress concentration. This re-establishes a unimodal distribution,, reclaiming the scaling hypothesis. We show that the misfit strain is renormalized and, thus, is not essential in determining the size distribution. We also demonstrate evidence for Smoluchowski ripening mechanism occuring during growth. Finally, we discuss implications of these issues on achieving a uniform Xi1-xGex/Si(001) island distribution, which is crucial for technological applications.
Local coordination structure and electronic structure of the large electron mobility amorphous oxide semiconductor In-Ga-Zn-O: Experiment and ab initio calculations

Ionic amorphous oxide semiconductors (IAOSs) are new materials for flexible thin film transistors that exhibit field-effect mobilities of $\ensuremath{\sim}10\phantom{\rule{0.3em}{0ex}}{\mathrm{cm}}^{2}\phantom{\rule{0.2em}{0ex}}{\mathrm{V}}^{\ensuremath{-}1}\phantom{\rule{0.2em}{0ex}}{\mathrm{s}}^{\ensuremath{-}1}$ [K. Nomura et al., Nature 488, 432 (2004)]. The local coordination structure in an IAOS, In-Ga-Zn-O ($a$-IGZO), was examined using extended x-ray absorption fine structure analysis combined with ab initio calculations. The short-range ordering and coordination structures in $a$-IGZO are similar to those in the corresponding crystalline phase, $\mathrm{In}\mathrm{Ga}\mathrm{Zn}{\mathrm{O}}_{4}$, and edge-sharing structures consisting of In-O polyhedra remain in the amorphous structure. The ${\mathrm{In}}^{3+}$ $5s$ orbitals form an extended state with a band effective mass of $\ensuremath{\sim}0.2{m}_{e}$ at the conduction band bottom.
Intermolecular Relaxation Energies in Anthracene

A type of angle-dependent uv photoemission measurement has been used to study variations in the intermolecular polarization effect at the surface of thin condensed anthracene films. The top molecular layer exhibits a 1.2-eV relaxation energy in response to the polarization of the hole state created in photoemission event. The second and subsequent layers exhibit a different value of about 1.5 eV. This result corresponds to the observation of a surface electronic molecular-ion state on a molecular solid.
Coercive inequalities for certain classes of bounded regions

In this paper, sufficient conditions are given for the coerciveness of formally positive integrodifferential forms over complex-valued functions satisfying zero boundary conditions in certain bounded domains in R2; the boundaries need not be smooth. This work extends results given by the author in Comm. Pure Appl. Math., November 1969. In addition, sufficient conditions and partial necessity conditions are given for coercive-type inequalities involving differential operators in the Holder norm; here the results hold for complexvalued functions with no boundary conditions; the regions are bounded subdomains of R. having the cone property. Introduction. In a previous paper [6] the author stated and proved two sufficient conditions for coerciveness of formally positive, constantcoefficient, homogeneous integrodifferential forms over complex-valued functions defined on sectors in the plane. The first part of this paper extends these results to the nonconstant nonhomogeneous case and certain types of bounded subdomains on R2. In the second part of this paper, some coerciveness-type results are derived for the Holder norm. I. L2-inequalities. 1.0. DEFINITIONS. If Q is a domain in R2, let C (Q) be the class of all complex-valued functions defined and continuous on Q2 and m times continuously differentiable on Q, and all of whose derivatives of order <t vanish on MQ, the boundary of Q. Let Q, be an open sector (which may be a half-plane, but not a halfline) in R2 with vertex at x0, and let Be be the open ball of radius 8 about x0. We will say that a domain Q * is of special type if it is of the form Q,) nBR Presented to the Society, April 17, 1970; received by the editors November 2, 1970. AMS 1970 subject classifications. Primary 31B45; Secondary 31A10, 31B10, 31J50.
Radar Determination of Snowfall Rate and Accumulation

Abstract A unique method that provides for relating radar-measured reflectivity factors to snowfall rates at the ground is presented. Data were provided by a CPS-9, 3.2 cm radar from six 1978 Massachusetts snowstorms A best-fit power-law relationship between hourly-averaged snowfall rate (depth) and radar reflectivity factor is determined. This derived relationship is found to be Z = 5.07S1. 65 with a correlation coefficient of 0.91. With this relationship hourly snowfall rates are found to be accurate to within +41 to −29% and total storm snowfall accumulation to within +44 to −31%.
Measurements of osmotic permeability in the Malpighian tubules of an insect, Rhodnius prolixus Stål

(i) With use of a novel experimental method, an improved estimate has been obtained for the value of the osmotic permeability (Pos) of RhodniusMalpighian tubules, 4.3 x 10-3 cm s-1 osmol-1 l. Corrections for unstirred layer effects permit a further 35% increase in the value of Pos, to 5.8 x 10-3 cm s-1 osmol-1 l. (ii) In the lower Malpighian tubule, Pos decreases from 3.4 x 10-3 cm s-1 osmol-1 l at the junction with the upper Malpighian tubule to 0.4 x 10-3 cm s-1 osmol-1 l at the junction with the gut. In lower tubules stimulated with 5-HT, Pos is reduced over most of their length by about 50% . It is suggested that reduced values of Pos in the lower portions of the lower tubule prevent water movements accompanying 5-HT-stimulated KCl resorption over the same area of the tubule. (iii) Values of Pos in the upper segment of the upper tubule are discussedin relation to proposed mechanisms for coupling water movements to ion transport during isosmotic secretion by the tubule.
Evolution of wavelike disturbances in shear flows : a class of exact solutions of the Navier-Stokes equations

New classes of exact solutions of the incompressible Navier-Stokes equations are presented. The method of solution has its origins in that first used by Kelvin (Phil. Mag. 24 (5), 188-196 (1887)) to solve the linearized equations governing small disturbances in unbounded plane Couette flow. The new solutions found describe arbitrarily large, spatially periodic disturbances within certain two- and three-dimensional ‘ basic ’ shear flows of unbounded extent. The admissible classes of basic flow possess spatially uniform strain rates; they include two- and three- dimensional stagnation point flows and two-dimensional flows with uniform vorticity. The disturbances, though spatially periodic, have time-dependent wavenumber and velocity components. It is found that solutions for the disturbance do not always decay to zero ; but in some instances grow continuously in spite of viscous dissipation. This behaviour is explained in terms of vorticity dynamics.
HEAD ROTATION EFFECTS ON THE FLOW AND HEMODYNAMICS OF THE HUMAN CAROTID BIFURCATION

The use of realistic anatomic human carotid artery bifurcation (CB) models with a realistic blood waveform leads to physiologically relevant numerical simulations. To study the effects of head posture on the geometry and hemodynamics of the CB, Magnetic resonance imaging (MRI) was used on six healthy volunteers in two different head postures: 1) the supine neutral (N) and 2) the prone with rightward head rotation (P) up to 80°. Geometric differences with posture change in both the left (LCA) and right (RCA) carotid arteries were reported before [1]. The blood velocity waveform for each individual was obtained using phase-contrast MRI (PCMRI) at five diameters upstream of CB. Results have shown that peak systolic blood flow rate is reduced, in the prone position for both RCA and LCA in all six volunteers. To investigate the effects of the reduced peak systolic flow on the hemodynamics of the CB, numerical simulations were performed for a volunteer that exhibited the most geometric changes for the prone position in comparison to the other five based on specific geometric parameters [1, 2]. For the two investigated head postures the observed measured input waveforms were used.Copyright © 2013 by ASME
Reflexion of an oblique shock wave by a turbulent boundary layer

Measurements are presented of the reflected wave field produced by a plane oblique shock wave impinging on a turbulent boundary layer at an initial Mach number of 2·5. The outgoing waves are either a single shock, with the same deflexion as the incident shock, or a shock of approximately 10° deflexion followed by a region of compression in which is embedded an expansion fan having the same turning as the incident shock. The transition between these two types of wave field was not studied, but it is fairly abrupt and appears to be closely linked to the onset of boundary-layer separation. The observed wave systems broadly agree with the suggestions of a number of previous workers, but not with a recent theoretical treatment. Surface-pressure measurements and oil flow photographs are used to determine the onset of separation, and from these it is found that the overall pressure rise associated with incipient separation is rather smaller than previous work would suggest.
Terminal Sliding Mode Control of Mobile Wheeled Inverted Pendulum System with Nonlinear Disturbance Observer

A terminal sliding mode controller with nonlinear disturbance observer is investigated to control mobile wheeled inverted pendulum system. In order to eliminate the main drawback of the sliding mode control, “chattering” phenomenon, and for compensation of the model uncertainties and external disturbance, we designed a nonlinear disturbance observer of the mobile wheeled inverted pendulum system. Based on the nonlinear disturbance observer, a terminal sliding mode controller is also proposed. The stability of the closed-loop mobile wheeled inverted pendulum system is proved by Lyapunov theorem. Simulation results show that the terminal sliding mode controller with nonlinear disturbance observer can eliminate the “chattering” phenomenon, improve the control precision, and suppress the effects of external disturbance and model uncertainties effectively.
Optically thick lines in a quiescent prominence - Profiles of Lyman-alpha, Lyman-beta /H I/, K and H /Mg II/, and K and H /Ca II/ lines with the OSO 8 LPSP instrument

A full set of observations of the resonance lines of Mg II, Ca II, H I (and O VI) and the Ly.beta. (H I) line has been obtained with the LPSP instrument on OSO 8. The observing modes (images, profiles) and the procedures of analysis are described, and special attention is paid to the intensity calibrations. Typical line profile parameters (widths,intensities) are summarized in Table 1. The Ca II lines have a low opacity: in the K line center it varies from 1.4 to 3.2. Nonthermal velocities range from 5 to 9 km s/sup -1/, and line shifts are small but reach 8 km s/sup -1/ at the edges. Intensities are lower than the incident chromospheric intensities multiplied by the dilution factor. The ratio of K/sub 3/ and H/sub 3/ intensities (K/sub 3//H/sub 3/) is approx.1.4. The Mg II lines are measured in the whole prominence only. Departures from Gaussian profiles may result from the integration of many elements with different velocities along the line of sight and also from line saturation. However, we observe an intensity ratio k/h of approx.1. 6, higher than the K/H ratio (as it is in the chromosphere). This result can be understood if the source functionmore » of resonance lines of Mg II and Ca II is dominated by the incident radiation, but the important width of Mg II lines, as compared to Ca II lines, is not explained. The full profiles of Ly.cap alpha. and Ly.beta. (H I) lines are observed for the first time in a quiescent prominence. Both are reversed, with a separation of 0.35-0.40 A for Ly.cap alpha. and 0.33 A for Ly.beta. Intensities are about equal to the incident chromospheric intensities multiplied by the dilution factor. Opacities are very high, and the radiation transfer is dominated by the scattering of chromospheric Ly.cap alpha. and Ly.beta. photons. The Ly.cap alpha. /Ly.beta. ratio is lower than the chromospheric one. The ratio of ly.cap alpha. to Ca K intensities does not vary very much. Both features indicate that the ionizing Lyman continuum penetrates fully in the prominence. « less
Solutions of the d'Alembert and Klein-Gordon equations confined to a region with one fixed and one moving wall

General solutions of the Klein-Gordon equation satisfying the Dirichlet boundary conditions on one fixed wall and the other wall moving with a constant velocity are derived. These solutions are specified by an arbitrary periodic function whose period is equal to twice the value of the rapidity of the moving wall. Choosing this function as a combination of trigonometric functions one obtains the solutions derived recently by Koehn. The method is also tested in the case of the d'Alembert equation where it reproduces in a simple manner well-known results.
The Hochschild Cohomology Ring of a One Point Extension

Abstract This paper studies the ring structure of the Hochschild cohomology ring of an algebra. The first main result gives a ring homomorphism from the Hochschild cohomology ring of an algebra A to the Ext-algebra of an A-module. Then, for a one point extension B of a finite dimensional algebra A, we relate the ring structures of the Hochschild cohomology rings of A and B thus giving a method of constructing algebras with non-trivial ring structure on the Hochschild cohomology ring.
Applications of spectral imaging using a tunable laser source

Hyperspectral reflectance imaging in the visible and NIR spectral ranges has considerable utility for revealing spatial and chemical complexity in both biological systems and manufactured products. Conventional imaging systems are based on broad-band illumination in tandem with a spectrometer or tunable filter placed between the sample and the detector. These systems are typically slow (require seconds of integration per wavelength step), and the CW broad-band source can cause significant heating of the sample. An alternative method is to use a tunable, pulsed, high-peak-power (low average power) source coupled with a broad-band detector. This approach offers a reduction in data acquisition time, the inherent ability to stop motion, and data collection at ambient temperature. An integrated system based on a 5- ns pulsed laser tunable from 430 nm to 2150 nm has been used to obtain hyperspectral images in both the visible and NIR spectral ranges. A number of camera/lens options allow for varied spectral bandwidths and the FOV, ranging from 11 × 15 mm2 to 15 × 20 cm2. An entire hyperspectral image stack can be collected in as little as 20 s. This method, allowing fast, room-temperature data acquisition, has sufficient sensitivity to produce data that can be successfully processed using spectral derivatives and multivariate analysis. We discuss several applications, both in vivo and otherwise, of this alternative approach to visible/NIR hyperspectral imaging.