Miracle-dz/UniFAR-FTUs huggingface dataset:
A Brunn-Minkowski Type Theorem on the Minkowski Spacetime

Abstract In this article, we derive a Brunn-Minkowski type theorem for sets bearing some relation to the causal structure on the Minkowski spacetime ${{\mathbb{L}}^{n+1}}$ . We also present an isoperimetric inequality in the Minkowski spacetime ${{\mathbb{L}}^{n+1}}$ as a consequence of this Brunn-Minkowski type theorem.
Mapping potential‐vorticity dynamics on Jupiter. I: Zonal‐mean circulation from Cassini and Voyager 1 data

Maps of Ertel potential vorticity on isentropic surfaces (IPV) and/or quasi‐geostrophic potential vorticity (QGPV) are well established in dynamical meteorology as powerful sources of insight into dynamical processes involving ‘balanced’ flow. In the present study, we derive maps of zonal‐mean IPV and QGPV in Jupiter's upper troposphere and lower stratosphere by making use of a combination of velocity measurements, derived from the tracking of cloud features in images from the Voyager 1 and 2 and Cassini missions, and thermal measurements from the Voyager 1 IRIS and Cassini CIRS instruments. IPV and QGPV are mapped and compared for the entire globe between latitudes ±55°. Profiles of zonally averaged PV show some evidence for a step‐like pattern suggestive of local PV homogenization, separated by strong PV gradients in association with eastward jets, though on differing scales in the northern and southern hemispheres. The northward gradient of PV (IPV or QGPV) is found to change sign in several places in each hemisphere, even when baroclinic contributions are taken into account. The relationship of lateral gradients of IPV and QGPV with the corresponding mean zonal flows indicate that the northern hemisphere may be closer to marginal stability with respect to Arnol'd's second stability theorem than the southern hemisphere. Copyright © 2006 Royal Meteorological Society
Effect of Brief Loud Noise on Decision Making

An experiment was designed to investigate whether irrelevant loud bursts of low‐frequency noise affected decision‐making unfavorably. Analysis of the results revealed a significant decrement in performance due to the noise distraction. Scores for the whole of a 4‐min test were unimpaired because only those responses immediately following the noise were affected. A second experiment demonstrated that effects were related to intensity.
Persistence under relaxed point-dissipativity (with application to an endemic model)

An approach to persistence theory is presented which focuses on the concept of uniform weak persistence. By using the most elementary dynamical systems concepts only, it can be shown that uniform weak persistence implies uniform strong persistence. This even holds under relaxed point dissipativity. Uniform weak persistence can be proved by the method of fluctuation or by analyzing the boundary flow for acyclicity with point dissipativity being only required in a neighborhood of the boundary. The approach is illustrated for a model describing the spread of a fatal infectious disease in a population that would grow exponentially without the disease. Sharp conditions are derived for both host and disease persistence and for host limitation by the disease.
A differential-capacitance transducer for measuring small displacements

Although three-terminal capacitors have been used to measure accurately small displacements in air and vacuum, it is usually impractical to use them in dielectric liquids, due to the strong dependence of the permittivity on purity and temperature. A differential-capacitance transducer in the form of a guarded disk between parallel plates was only slightly affected by variation in temperature over the range 18 to 90? C, and was unaffected by variation in the relative permittivity of air or liquid dielectric from 1 to 49. Displacements up to 2? 5 mm could be measured with a precision better than 0? 01 ? m.
A Property of Maximum Likelihood Estimators of Location and Scale Parameters

It is shown that the maximum likelihood estimators (m.l.e.'s) $\hat \alpha $ and $\hat \beta $ of the location and scale parameters $\alpha $ and $\beta $ have the property that ${{\hat \beta } / \beta }$, ${{(\hat \alpha - \alpha )} / \beta }$ and ${{(\hat \alpha - \alpha )} / {\hat \beta }}$ are pivotal functions with distributions independent of both parameters. Similar results are seen to hold for other types of distributions by making suitable transformations.
Improving Large-Eddy Simulation of Neutral Boundary Layer Flow across Grid Interfaces

AbstractIncreasing computational power has enabled grid resolutions that support large-eddy simulation (LES) of the atmospheric boundary layer. These simulations often use grid nesting or adaptive mesh refinement to refine the grid in regions of interest. LES generates errors at grid refinement interfaces, such as resolved energy accumulation, that may compromise solution accuracy. In this paper, the authors test the ability of two LES formulations and turbulence closures to mitigate errors associated with the use of LES on nonuniform grids for a half-channel approximation to a neutral atmospheric boundary layer simulation. Idealized simulations are used to examine flow across coarse–fine and fine–coarse interfaces, as would occur in a two-way nested configuration or with block structured adaptive mesh refinement. Specifically, explicit filtering of the advection term and the mixed model are compared to a standard LES formulation with an eddy viscosity model. Errors due to grid interfaces are evaluated by.
On Turbulent Flows Dominated by Curvature Effects

A technique for improving the numerical predictions of turbulent flows with the effect of streamline curvature is developed. Separated flows and the flow in a curved duct are examples of flowfields where streamline curvature plays a dominant role. New algebraic formulations for the eddy viscosity incorporating the k-epsilon turbulence model are proposed to account for various effects of streamline curvature. The loci of flow reversal of the separated flows over various backward-facing steps are employed to test the capability of the proposed turbulence model in capturing the effect of local curvature.
Silicon nanowire piezoresistance: Impact of surface crystallographic orientation

We investigate piezoresistance in lithographically defined silicon nanowires of various cross-sectional aspect ratios. Both ⟨110⟩- and ⟨100⟩-oriented nanowires are investigated under ⟨110⟩-oriented strain. The nanowire thickness is varied from 23 to 45 nm and the nanowire width is varied from 5 to 113 nm. Our data shows piezoresistance in silicon nanowires being a surface induced effect with {110} surfaces inducing a much larger piezoresistance than {100} surfaces. This is consistent with a higher density of surface states on {110} surfaces than on {100} surfaces. Our experimental findings support recent computational work pointing toward surface states being the source of giant piezoresistance in silicon nanowires.
Non-linear design for cost of feedback reduction in systems with large parameter uncertainty †

Feedback systems containing linear, minimum-phase plants with large parameter uncertainty may be designed to achieve specified performance tolerances over the entire range of parameter uncertainty. The principal ‘cost of feedback’ is in the feedback loop bandwidth, which is generally much larger than that of the system as a whole. This makes the system very sensitive to sensor noise and high-frequency parasitics. It is shown how a non-linear ‘first-order reset element’ (FORE) may be used to drastically decrease the feedback loop transmission bandwidth. One is logically led to FORE by simple, linear feedback frequency response concepts. The paper assumes that the primary design problem is to satisfy quantitative response tolerances to command inputs. However, disturbances at the plant are not neglected, but the specification on such disturbances is in the damping of the step response. An important feature of the non-linear design is that the system response to command inputs is almost exactly that of a lin.
Convective Transport Around a Rotating Square Cylinder at Moderate Reynolds Numbers

Two-dimensional numerical simulation is performed to analyze the thermofluidic transport around a rotating square cylinder in an unconfined medium. The convective transport originates as a consequence of the interaction between a uniform free-stream flow and the flow evolving due to the rotation of the sharp-edged body. A finite volume-based method and a body-fitted grid system along with the moving boundaries are used to obtain the numerical solution of the incompressible Navier–Stokes and energy equations. The Reynolds number based on the free-stream flow is considered in the range 10 ≤ Re ≤ 200, and the dimensionless rotational speed of the cylinder is kept 0 ≤ Ω ≤ 5. Depending on the Reynolds number and the rotational speed of the cylinder, the transport characteristics change. For the range 10 ≤ Re < 50, the flow remains steady irrespective of the rotational speed. In the range 50 ≤ Re ≤ 200, regular low-frequency Kármán vortex shedding (VS) is observed up to a critical rate of rotation (Ωcr ). Beyond Ωcr , the global convective transport shows a steady nature. The rotating circular cylinder also shows likewise degeneration of Kármán VS at some critical rotational speed. However, the heat transfer behavior varies significantly with a rotating circular cylinder. Such thermofluidic transport around a spinning square in an unconfined free-stream flow is reported for the first time.
High-current electric-discharge light sources

This review presents systematically the results of investigations of the physics of high-current discharges in dense low-temperature plasmas and it is based, to a considerable extent, on the results of theoretical and experimental investigations carried out since 1967 at the Lebedev Physics Institute and in the Physics Department of the Moscow State University. The prime aim of these investigations was to determine the possibility of using high-current discharges in dense plasmas as radiation sources for the pumping of modern high-power lasers. It was found that the physics of high-current light-emitting discharges went well beyond the utilitarian task of providing high-power light sources, and covered little known branches of the physics of dense plasmas at relatively low temperatures, when the radiation dominated the energy balance and transfer processes. This general approach to the physics of plasmas is adopted in the present review. It comprises a theoretical part (Chap. I), which deals with the results of theoretical analyses of the formation, equilibrium, and stability of plasmas in high-current light-emitting discharges, and a part (Chap. II) which gives the results of an experimental investigation of the physical processes in such discharges and analyzes their characteristics as light sources. The review is intended for physicists and engineers investigating high-power light sources, magnetohydrodynamics, and physics of dense low-temperature plasmas. The review covers papers which appeared up to the beginning of 1973.
The Effect of Coverings on Heat Transfer from a Window to a Room

Abstract The presence of a blind adjacent to a window affects the natural convective and radiant heat transfer from the window to the room. As a result, the use of a shading device will change the heat transmission and solar heat gain through the window. A number of numerical and experimental studies of the effects of blinds on the heat transfer from a window have therefore been undertaken, with some of the main features of these studies being described here. In these studies, attention has been given to Venetian, vertical, and plane blinds, although the major attention has been given to Venetian blinds. Initial studies examined the effect of all three types of blinds on the natural convective heat transfer at an indoor glazing surface when there is no solar irradiance. Supporting experimental studies using mainly interferometry were then undertaken, particularly for the Venetian blind case. The numerical and experimental work was then extended to include the effects of solar radiation, in particular the effect of heat generation in the blind resulting from absorbed solar radiation. In addition to providing basic information on the effects of blinds on the heat transfer process, the studies described here will assist in expanding available software for predicting window heat transfer to include the effect of window coverings and assist in the selection of energy-efficient window coverings.
Finite volumes for 2D shallow-water flow with bed-load transport on unstructured grids

In this work, two-dimensional (2D) bed-load transport simulations based on the depth-averaged shallow-water equations and the Exner equation are presented. The Exner equation is written assuming that bed-load transport is governed by a power law of the depth-averaged flow velocity and by a flow/sediment interaction parameter acting as a calibration coefficient. Uncoupled and coupled numerical resolutions of the global problem are considered. A Roe-type first-order upwind scheme has been applied as approximate Riemann solver for the discretization on 2D unstructured meshes. The uncoupled resolution is presented as a simple extension of a previous 2D shallow-water model. The details of the new implementation in the coupled system problem are provided. The models are tested comparing with exact solutions of 2D cases as well as experimental laboratory data.
Case studies and generalizability: grounded theory and research in science education

'Grounded theory' may be used to bridge between case studies and large-scale surveys, which enables the strengths of both to be combined in the same research programme. Starting with detailed in-depth studies of individual cases, a general model may be constructed through the key processes of 'theoretical sensitivity', 'theoretical sampling' and 'theoretical saturation'. Unlike most qualitative methodology, the grounded theory approach claims to produce testable outcomes: grounded theory is intended to lead to predictions which may be subject to traditional experimental and statistical testing. This paper describes one example of the application of a grounded theory approach to research into the learning of science, and considers the generalizability of the research results.
PIC‐MCC Model of a Plasma in the Vicinity of a Cylindrical Langmuir Probe

A full kinetic model of an argon plasma in the vicinity of a cylindrical Langmuir probe is developed and presented. The model is one‐dimensional in the radial direction and three‐dimensional in velocity space. The model simulates the plasma transition from the bulk to the probe surface and particle collection by the probe. Monte Carlo particle‐neutral collisions are considered in the model to account for collisional effects on the probe particle collection. Particles are loaded at the plasma bulk boundary with Maxwellian velocity distribution functions. The model output includes space potential and particle density profiles as a function of radius. The model also reproduces typical Langmuir probe current‐voltage characteristics at different pressures, plasma parameters and probe dimensions. Modelled electron and ion currents at different pressures for similar plasma parameters are presented, analysed and compared. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Temperature and Density Measurements in Free Jets and Shock Waves

The fluorescence stimulated by a 17.5‐kV electron beam probe was used to obtain measurements of rotational temperature and gas density in supersonic nitrogen jets expanding from room temperature. The parameter P0d (where P0 is the stagnation pressure in Torricelli and d is the orifice exit diameter in millimeters) was varied from 15 to 480 Torr‐mm. Density measurements were made using an interference filter‐photomultiplier combination. The experimental density data follow the axial isentropic density distribution in regions of rotational nonequilibrium. Rotational temperature measurements were obtained from rotational spectra of the 0–0 band of the N2+ first negative system. The experimentally determined rotational temperatures, which initially follow the axial isentropic temperature distribution in a free jet, depart from the isentropic curve at low temperatures and freeze at a constant value, indicating a substantial degree of nonequilibrium in the expansion. A shock holder was inserted in the jet and a.
Impact of different initial conditions on the growth of polar lows: idealised baroclinic channel simulations

The development of a polar low is simulated in an ideal baroclinic channel with the objective of studying the relative influence of different initial conditions on certain characteristics of the polar low. The basic state in the channel has a baroclinic jet at the tropopause level superposed by potential vorticity anomalies. The upper‐level perturbation leads to the genesis of a polar low through baroclinic instability. During its growth, the polar low is driven by a combination of baroclinic and convective processes as the vertical motion associated with the polar low is found to be forced simultaneously by the adiabatic and diabatic omega‐forcing terms in the quasi‐geostrophic omega equation. The degree of baroclinicity, surface heating and the scale of the upper‐level anomaly were each reduced, and static stability increased separately in a series of sensitivity experiments. The results show that the pattern of the vertical motion, the growth rate and phase speed of the polar low are highly sensitive to the modifications in the background conditions. In particular, the surface temperature and baroclinicity appear to be crucial in determining the strength of the vertical motion associated with the polar low. The scale and structure of the polar low are more vulnerable to the scale of the upper‐level anomaly and initial baroclinicity than to the rest of the parameters tested. In all the sensitivity experiments, the formation of the polar low gets delayed and its intensity, in terms of the surface pressure, reduced due to the modified initial conditions. The reduced intensity suppresses the tendency for a vertical coupling of upper‐ and lower‐level features of the polar low. Copyright © 2011 Royal Meteorological Society
Femtosecond spontaneous parametric upconversion and downconversion in a quadratic nonlinear medium

Spontaneous parametric upconversion (SPUC) and spontaneous parametric downconversion (SPDC) have been observed in the β-barium borate (BBO) crystal, and their mechanisms are experimentally and theoretically investigated. SPUC, tuned from 530 to 600 nm with a FWHM of about 25 nm, can be attributed to the sum frequency between the quantum noise and the fundamental laser pulse in the type II phase matching condition (e+o→e). SPDC, tuned from 480 to 520 nm with a FWHM of about 15 nm, can be attributed to the difference frequency between the quantum noise and the fundamental laser pulse in the type I phase matching condition (e→o+o).
Automorphism groups of Ree type Deligne-Lusztig curves and function fields.

This paper studies and proves uniqueness of a family of curves and corresponding function fields associated to Ree groups [9]. The curves are particular in two senses. First of all, they have the largest possible number of irrational points curves ofthat genera can have according to Weil's explicit formulas. Secondly, they have very large groups of automorphisms compared to their genera their sizes exceed by far the Hurwitz upper bound 84(g— 1) valid in characteristic zero [6].
Damping phenomena in Co90Fe10/Ni multilayers and alloys

We used perpendicular ferromagnetic resonance to measure the damping parameter in Co90Fe10/Ni multilayers over a wide range of layer thicknesses. The magnetic anisotropy within this range varied from in-plane to out-of-plane. We measured (Co90Fe10)xNi1−x alloys of identical thicknesses over the same compositional range of Co90Fe10 and Ni in order to isolate the influence of the multilayer structure. The damping parameter varied from 0.004 to 0.030 and depended only on the relative amounts of Co90Fe10 and Ni and was independent of the magnetic anisotropy and layer structure.
Dielectric relaxation of atomic-layer-deposited HfO2 thin films from 1kHzto5GHz

The dielectric relaxation of HfO2 thin films grown by atomic-layer deposition (ALD) was studied as a function of frequency from 1kHzto5GHz. The dielectric relaxation of the ALD HfO2 films followed a power-law dependence known as the Curie–von Schweidler relaxation law both in the kHz and GHz ranges, and the relaxation exponents were consistent with the measured dielectric losses. The behavior of the dielectric response for the HfO2 thin films may be attributed to defect sites in the HfO2 layer and∕or interface.
Seasonal albedo of an urban/rural landscape from satellite observations

Abstract The spatial distribution and seasonal variation of surface reflectance and albedo in a heterogeneous urban/rural landscape (Hartford, Conn.) was examined using 27 calibrated Landsat observations. Atmospheric effects were removed by a target calibration procedure using 22 urban targets (building rooftops and parking lots) whose reflectance has been measured by a radiometer. Landsat bands 4 and 7, representing the visible and near-infrared portions of the spectrum, are calibrated using linear regression analysis to relate the measured surface reflectance of the target to its satellite-observed radiance. The visible and near-infrared reflectance were integrated into a measure of albedo by the use of a weighted average formula which incorporates the spectral reflectivity of the surface of interest and the spectral distribution of solar radiation. Three distinct formulae were employed for vegetated surfaces, nonvegetated surfaces, and snow-covered surfaces. Visible reflectance, near infrared reflectan.
Piezoelectric properties of low-temperature sintered Li-modified (Na, K)NbO3 lead-free ceramics

LiNbO3-doped (Na, K)NbO3 lead-free piezoceramics were prepared by conventional sintering at a temperature as low as 950 °C using excess Na2O additives. The crystal structure changed from orthorhombic to tetragonal with increasing LiNbO3 amount since the phase transition temperature TO−T shifted downward. In the region of two-phase coexistence, enhanced piezoelectric constant d33 (280 pC/N) and electromechanical coupling factor kp (48.3%) with a high Curie temperature TC (475 °C) were obtained in the nominal composition 0.92(Na0.535K0.48)NbO3–0.08LiNbO3. Our results open up the way to low-temperature sintering of (Na, K)NbO3-based lead-free piezoceramics with high performance.
Temporal Effects in Simultaneous Masking by White‐Noise Bursts

The motivation of the research described was to investigate the behavior of a masking transient that indicates that masking of a short signal pulse by a longer white‐noise burst is stronger at the beginning of the masker burst than later. The threshold of signal pulses masked by masker bursts was measured as a function of different variables such as bandwidth and center frequency of the signal, delay between onset of masker and onset of signal, duration of signal and masker, level of masker, and repetition rate. The results reveal very little “overshoot” of the threshold of short pulses as a function of the ON time of the masker if the signal and the masker have the same or similar broad spectra. The overshoot increases up to 13 dB as the bandwidth of the signal decreases down to that of a tone. The size of the “overshoot” and the prior excitation seem to be related to each other. Taking this in account, the thresholds under different conditions can be calculated on the basis of detection models. The meas.