Miracle-dz/UniFAR-FTUs huggingface dataset:
Numerical study of a coastal fog event over Casablanca, Morocco

This numerical study focuses on a dense fog event that occurred during the night of 21–22 January 2008 in the Grand Casablanca region, on the northwestern coast of Morocco. This fog event, which lasted for 15 h, is simulated by the mesoscale non‐hydrostatic model Meso‐NH and analyzed using conventional meteorological observations from two synoptic stations of the region, Meteosat Second Generation (MSG) satellite imagery and the European Centre for Medium‐Range Weather Forecasts (ECMWF) ERA‐Interim reanalysis. Results demonstrate that this fog event included the formation of radiation fog over a continental zone and its extension to the coastal zone through the lowering of low‐stratus clouds, which is in agreement with observations and is captured well by the Meso‐NH model. Sensitivity experiments show that coastal fog prediction improves with improved sea‐surface temperature. Model skill also depends on the adjustment of microphysical parameters when a single‐moment microphysical scheme is used, and on reliable initial conditions.
Further development of a parameterization for convective turbulent dust emission and evaluation based on field observations

Further developments of a parameterization scheme for convective turbulent dust emission (CTDE) are presented. The scheme is advanced by including (1) a new statistical description of instantaneous momentum flux, (2) a correction function for cohesive force to account for the effect of soil moisture, and (3) a correction function for lifting force to consider the effect of vegetation roughness elements. The probability density function describing instantaneous momentum flux is now derived from large‐eddy simulations for different atmospheric stabilities. The vegetation correction function is based on a drag partition theory. Additional improvements on the representations of interparticle cohesive force and particle size distribution are introduced. The new CTDE scheme is tested against the field data obtained at a sand storm monitoring station in the Horqin Sandy Land in China in 2011 and during the Japan‐Australia Dust Experiment in Australia in 2006.
Optical properties of semiconducting iron disilicide thin films

Iron disilicide thin films were prepared by furnace reaction of ion beam sputtered iron layers with single‐crystal silicon wafers and with low‐pressure chemical vapor deposition (LPCVD) polycrystalline silicon thin films. X‐ray diffraction indicates the films are single‐phase, orthorhombic, β‐FeSi2. Impurity levels are below the detection limit of Auger spectroscopy. Normal incidence spectral transmittance and reflectance data indicate a minimum, direct energy gap of 0.87 eV. The apparent thermal activation energy of the resistivity in the intrinsic regime is about half of this minimum optical gap. With such a direct band gap, the material may be suitable for the development of both light‐sensitive and light‐emitting thin‐film devices within the silicon microelectronics technology.
Vector recording in perpendicular media

A dynamic hierarchical micromagnetic model has been used to study the effect of off-axis (in-plane) fields upon the recording properties of perpendicular media. The transient and high-frequency switching response are improved. On longer timescales, the susceptibility and squareness are significantly increased. However, transitions written in the medium with a pole head change only slightly when the in-plane field is included. This is because the transition gets written at a point where the head field gradient is lower and because in-plane demagnetizing fields act to reduce the in-plane head field.
Pattern formation induced by cross-diffusion in a predator–prey system

This paper considers the Holling–Tanner model for predator–prey with self and cross-diffusion. From the Turing theory, it is believed that there is no Turing pattern formation for the equal self-diffusion coefficients. However, combined with cross-diffusion, it shows that the system will exhibit spotted pattern by both mathematical analysis and numerical simulations. Furthermore, asynchrony of the predator and the prey in the space. The obtained results show that cross-diffusion plays an important role on the pattern formation of the predator–prey system.
Novel channel models for visible light communications

In this paper, we investigate channel modeling for visible light communications (VLC) using non-sequential ray tracing simulation tools. We create three dimensional realistic simulation environments to depict indoor scenarios specifying the geometry of the environment, the objects inside, the reflection characteristics of the surface materials as well as the characteristics of the transmitter and receivers, i.e., LED sources and photodioes. Through ray tracing simulations, we compute the received optical power and the delay of direct/indirect rays which are then used to obtain the channel impulse response (CIR). Following this methodology, we present CIRs for a number of indoor environments including empty/furnished rectangular rooms with different sizes and wall/object materials (e.g., plaster, gloss paint, wood, aluminum metal, glass) assuming deployment of both single and multiple LED transmitters. We further quantify multipath channel parameters such as delay spread and channel DC gain for each configuration and provide insights into the effects of indoor environment parameters (e.g., size, wall/object materials, etc.), transmitter/receiver specifications (e.g., single vs. multiple transmitters, location, rotation etc.) on the channel.
Semiclassical theory of spectral rigidity

The spectral rigidity ⊿(L) of a set of quantal energy levels is the mean square deviation of the spectral staircase from the straight line that best fits it over a range of L mean level spacings. In the semiclassical limit (ℏ→0), formulae are obtained giving ⊿(L) as a sum over classical periodic orbits. When L ≪Lmax, where Lmax ~ℏ-(N-1) for a system of N freedoms, ⊿(L) is shown to display the following universal behaviour as a result of properties of very long classical orbits: if the system is classically integrable (all periodic orbits filling tori), ⊿(L)═ 1/5L (as in an uncorrelated (Poisson) eigenvalue sequence); if the system is classically chaotic (all periodic orbits isolated and unstable) and has no symmetry, ⊿(L) ═ In L/2π2+Dif 1≪ L≪ Lmax (as in the gaussian unitary ensemble of random-matrix theory); if the system is chaotic and has time-reversal symmetry, ⊿(L) = In L/π2 + Eif 1 ≪ L ≪ Lmax (as in the gaussian orthogonal ensemble). When L ≫ Lmax, ⊿(L) saturates non-universally at a value, determined by short classical orbits, of order ℏ–(N–1) for integrable systems and In (ℏ-1) for chaotic systems. These results are obtained by using the periodic-orbit expansion for the spectral density, together with classical sum rules for the intensities of long orbits and a semiclassical sum rule restricting the manner in which their contributions interfere. For two examples ⊿(L) is studied in detail: the rectangular billiard (integrable), and the Riemann zeta function (assuming its zeros to be the eigenvalues of an unknown quantum system whose unknown classical limit is chaotic).
Defect-reduction mechanism for improving radiative efficiency in InGaN/GaN light-emitting diodes using InGaN underlayers

The influence of a dilute InxGa1-xN (x ∼ 0.03) underlayer (UL) grown below a single In0.16Ga0. 84N quantum well (SQW), within a light-emitting diode (LED), on the radiative efficiency and deep level defect properties was studied using differential carrier lifetime (DCL) measurements and deep level optical spectroscopy (DLOS). DCL measurements found that inclusion of the UL significantly improved LED radiative efficiency. At low current densities, the non-radiative recombination rate of the LED with an UL was found to be 3.9 times lower than the LED without an UL, while the radiative recombination rates were nearly identical. This suggests that the improved radiative efficiency resulted from reduced non-radiative defect concentration within the SQW. DLOS measurement found the same type of defects in the InGaN SQWs with and without ULs. However, lighted capacitance-voltage measurements of the LEDs revealed a 3.4 times reduction in a SQW-related near-mid-gap defect state for the LED with an UL. Quantitative a.
Intrinsic stress of epitaxial thin films

It is well known that thin films develop large intrinsic stress during their preparation. The stress originates from strained regions either within the thin films (grain boundaries, dislocations, voids, impurities) or at the film/substrate interface (lattice mismatch, different thermal expansion) or due to dynamical (recrystallization, interdiffusion) or gas adsorption processes. Since the magnitude of most of these stress contributions is directly correlated with film morphology as well as film growth, important structural information can be extracted from the intrinsic stress. Recent results on various epitaxial thin film systems growing via Volmer–Weber Ag/mica(001), Cu/mica(001), (Ag/Si(001)), Stranski–Krastanov (Ag/Si(001), Ge/Si(001)), and Frank–Van der Merwe modes (Si/Si(001), Fe/MgO(001)) are reviewed.
HR 1614 and the dissolution of a supercluster

A few main-sequence members of the HR 1614 supercluster have been found within 40 parsecs of the Sun. The convergent point of the proper motions is (A,D)=(8 h .38, −58.°7) and V TOT =59.0 km/s. Thirty-nine members of the HR 1614 group, with mean V=−58.4 km/s, have been found near the Sun as well as nineteen red giants within 200 parsecs. Both the supercluster and group members have Hyades abundance of heavy elements but CN strengths equalled by less than five percent of the stars near the Sun
'Meshsweeper': Dynamic Point-to-Polygonal-Mesh Distance and Applications

We introduce a new algorithm for computing the distance from a point to an arbitrary polygonal mesh. Our algorithm uses a multiresolution hierarchy of bounding volumes generated by geometric simplification. Our algorithm is dynamic, exploiting coherence between subsequent queries using a priority process and achieving constant time queries in some cases. It can be applied to meshes that transform rigidly or deform nonrigidly. We illustrate our algorithm with a simulation of particle dynamics and collisions with a deformable mesh, the computation of distance maps and offset surfaces, the computation of an approximation to the expensive Hausdorff distance between two shapes, and the detection of self-intersections. We also report comparison results between our algorithm and an alternative algorithm using an octree, upon which our method permits an order-of-magnitude speed-up.
Multi-channel signal separation based on cross-bispectra

The authors consider the problem in which they want to separate two (or more) signals that are coupled to each other through an unknown multiple-input-multiple-output linear time invariant system. They prove that the signals can be decoupled, or separated, using only the condition that they are statistically independent, and find even weaker sufficient conditions involving their cross-bispectra. By imposing these conditions on the reconstructed signals, they obtain a criterion for signal separation. A computationally efficient iterative algorithm for solving the proposed criterion, that only involves the iterative solution to a linear least squares problem, is presented. <<ETX>>
High-Energy Atmospheric Reentry Test Aerothermodynamic Analysis

The aerothermodynamic environment around an 8.3 m High-Energy Atmospheric Reentry Test vehicle is assessed. Twelve nose-shape configurations are generated, and their responses at the peak heating trajectory point are compared against the baseline nose shape. The possibility of a two-piece thermal protection system design at the nose is also considered, as are the surface catalytic affects of the aeroheating environment of such a configuration. Based on these analyses, an optimum nose shape is proposed to minimize the surface heating. The heat flux sensitivity of the optimum geometry to the angle of attack variations are also studied. A recommendation is also made for a two-piece thermal protection system design, for which the surface catalytic uncertainty associated with the jump in heating at the nose-inflatable aerodynamic decelerator juncture is reduced by a minimum of 93%. In this paper, the aeroshell is assumed to be rigid, and the inflatable fluid interaction effect is left for future investigations.
Roles of the Synoptic-Scale Wave Train, the Intraseasonal Oscillation, and High-Frequency Eddies in the Genesis of Typhoon Manyi (2001)*

AbstractExperiments using the Weather Research and Forecasting (WRF) Model were conducted to investigate the effects of multiscale motions on the genesis of Typhoon Manyi (2001) in the western North Pacific. The precursor signal associated with this typhoon genesis was identified as a northwest–southeast-oriented synoptic-scale wave train (SWT). The model successfully simulated the genesis of the typhoon in the wake of the SWT. Further experiments were conducted to isolate the effects of the SWT, the intraseasonal oscillation (ISO), and high-frequency (shorter than 3 days) eddies in the typhoon formation.Removing the SWT in the initial and boundary conditions eliminates the typhoon genesis. This points out the importance of the SWT in the typhoon genesis. It was noted that the SWT strengthened the wake cyclone through southeastward energy dispersion. The strengthening wake cyclone triggered multiple episodes of strong sustained convective updrafts, leading to aggregation of vertical vorticity and formatio.
Optical reflectance and transmittance of tissues: principles and applications

A discussion is presented of diagnostic and dosimetric optical measurements in medicine and biology. Topics covered include: tissue optical properties, tissue boundary conditions, and invasive versus noninvasive measurements. Clinical applications of therapeutic dosimetry and diagnostic spectroscopy are discussed. The principles of diffuse reflectance and transmittance measurements are presented. Experimental studies illustrate reflectance spectroscopy and steady-state versus time-resolved measurements. >
Model of the Thermodynamic Structure of the Trade-Wind Boundary Layer: Part I. Theoretical Formulation and Sensitivity Tests.

Abstract A numerical model which predicts the time variation of the thermodynamic structure of the trade-wind boundary layer is developed. Horizontally homogeneous conditions are assumed and the large-scale divergence, sea surface temperature and surface wind speed are specified externally. The model predicts the average value of mixing ratio and moist static energy in the subcloud and cloud layer and the slopes of these quantities in the cloud layer; the model also predicts the height of the transition layer (the layer which defines the boundary between the cloud and subcloud layer) and the height of the trade inversion. Subcloud layer convective fluxes are specified by using the bulk aerodynamic method for specifying the surface fluxes and a mixed-layer parameterization of the fluxes at the top of the subcloud layer. The moist convective processes are parameterized in terms of a mass flux which varies linearly with height and a cloud-environment difference in thermodynamic quantities which also varies l.
An immersed boundary finite difference method for LES of flow around bluff shapes

A three‐dimensional numerical model using large eddy simulation (LES) technique and incorporating the immersed boundary (IMB) concept has been developed to compute flow around bluff shapes. A fractional step finite differences method with rectilinear non‐uniform collocated grid is employed to solve the governing equations. Bluff shapes are treated in the IMB method by introducing artificial force terms into the momentum equations. Second‐order accurate interpolation schemes for all sorts of grid points adjacent to the immersed boundary have been developed to determine the velocities and pressure at these points. To enforce continuity, the methods of imposition of pressure boundary condition and addition of mass source/sink terms are tested. It has been found that imposing suitable pressure boundary condition (zero normal gradient) can effectively reproduce the correct pressure distribution and enforce mass conservation around a bluff shape. The present model has been verified and applied to simulate flow around bluff shapes: (1) a square cylinder and (2) the Tsing Ma suspension bridge deck section model. Complex flow phenomena such as flow separation and vortex shedding are reproduced and the drag coefficient, lift coefficient, and pressure coefficient are calculated and analyzed. Good agreement between the numerical results and the experimental data are obtained. The model is proven to be an efficient tool for flow simulation around bluff bodies in time varying flows. Copyright © 2004 John Wiley & Sons, Ltd.
Coupled Fixed-Point Theorems for Contractions in Partially Ordered Metric Spaces and Applications

Bhaskar and Lakshmikantham (2006) showed the existence of coupled coincidence points of a mapping from into and a mapping from into with some applications. The aim of this paper is to extend the results of Bhaskar and Lakshmikantham and improve the recent fixed-point theorems due to Bessem Samet (2010). Indeed, we introduce the definition of generalized -Meir-Keeler type contractions and prove some coupled fixed point theorems under a generalized -Meir-Keeler-contractive condition. Also, some applications of the main results in this paper are given.
Intermittency route to thermoacoustic instability in turbulent combustors

Abstract The dynamic transition from combustion noise to combustion instability was investigated experimentally in two laboratory-scale turbulent combustors (namely, swirl-stabilized and bluff-body-stabilized backward-facing-step combustors) by systematically varying the flow Reynolds number. We observe that the onset of combustion-driven oscillations is always presaged by intermittent bursts of high-amplitude periodic oscillations that appear in a near-random fashion amidst regions of aperiodic low-amplitude fluctuations. These excursions to periodic oscillations last longer in time as operating conditions approach instability and finally the system transitions completely into periodic oscillations. A continuous measure to quantify this bifurcation in dynamics can be obtained by defining an order parameter as the probability of the signal amplitude exceeding a predefined threshold. A hysteresis zone was observed in the bluff-body-stabilized configuration that was absent in the swirl-stabilized configuration. The recurrence properties of the dynamics of intermittent burst oscillations were quantified using recurrence plots and the distribution of the aperiodic phases was examined. From the statistics of these aperiodic phases, robust early-warning signals of an impending combustion instability may be obtained.
Cyclic Linearization and Island Repair in Sluicing

Cyclic Linearization is adopted to account for the island repair of Sluicing in English. The extraction of wh-phrase out of certain islands undergoes non-successive-cyclic movement, which yields conflicting ordering statements. The derivation can be rescued by deleting all ordering statements in IP, including those conflicting ones. Two arguments concerning Complex NP Constraint (relative clause) and Adjunct Island support the proposal.
Efficient algorithms using the multiplicative weights update method

Algorithms based on convex optimization, especially linear and semidefinite programming, are ubiquitous in Computer Science. While there are polynomial time algorithms known to solve such problems, quite often the running time of these algorithms is very high. Designing simpler and more efficient algorithms is important for practical impact. In this thesis, we explore applications of the Multiplicative Weights method in the design of efficient algorithms for various optimization problems. This method, which was repeatedly discovered in quite diverse fields, is an algorithmic technique which maintains a distribution on a certain set of interest, and updates it iteratively by multiplying the probability mass of elements by suitably chosen factors based on feedback obtained by running another algorithm on the distribution. We present a single meta-algorithm which unifies all known applications of this method in a common framework. Next, we generalize the method to the setting of symmetric matrices rather than real numbers. We derive the following applications of the resulting Matrix Multiplicative Weights algorithm: (1) The first truly general, combinatorial, primal-dual method for designing efficient algorithms for semidefinite programming. Using these techniques, we obtain significantly faster algorithms for obtaining O( logn ) approximations to various graph partitioning problems, such as S PARSEST CUT, BALANCED SEPARATOR in both directed and undirected weighted graphs, and constraint satisfaction problems such as MIN UNCUT and MIN 2CNF Deletion. (2) An O( n3) time derandomization of the Alon-Roichman construction of expanders using Cayley graphs. The algorithm yields a set of O (log n) elements which generates an expanding Cayley graph in any group of n elements. (3) An O (n3) time deterministic O(log n) approximation algorithm for the quantum hypergraph covering problem. (4) An alternative proof of a result of Aaronson that the γ-fat-shattering dimension of quantum states on n qubits is O( ng2 ). Using our framework for the classical Multiplicative Weights Update method, we derive the following algorithmic applications: (1) Fast algorithms for approximately solving several families of semidefinite programs which beat interior point methods. Our algorithms rely on eigenvector computations, which are very efficient in practice compared to the Cholesky decompositions needed by interior point methods. We also give a matrix sparsification algorithm to speed up the eigenvector computation using the Lanczos iteration. (2) O( logn ) approximation to the SPARSEST CUT and the BALANCED SEPARATOR problems in undirected weighted graphs in O(n 2) time by embedding expander flows in the graph. This improves upon the previous O(n4.5) time algorithm of Arora, Rao, and Vazirani, which was based on semidefinite programming.
H i in extremely metal deficient galaxies – III. Giant Metrewave Radio Telescope observations of blue compact galaxy HS 0822+3542

We present the results of Giant Metrewave Radio Telescope H i 21-cm line observations of the extremely metal deficient (XMD) blue compact galaxy (BCG) HS 0822+3542. HS 0822+3542 is the smallest known XMD galaxy; from Hubble Space Telescope (HST) imaging, it has been suggested that it actually consists of two still smaller (∼100 pc sized) ultra-compact dwarfs that are in the process of merging. The brighter of these two putative ultra-compact dwarfs has an ocular appearance, similar to that seen in galaxies that have suffered a penetrating encounter with a smaller companion. From our H i imaging, we find that the gas distribution and kinematics in this object are similar to that of other low-mass galaxies, albeit with some evidence for tidal disturbance. On the other hand, the H i emission has an angular size ∼25 times larger than that of the putative ultra-compact dwarfs. The optical emission is also offset from the centre of the H i emission. HS 0822+3542 is located in the nearby Lynx–Cancer void, but has a nearby companion low surface brightness dwarf galaxy SAO 0822+3545. In light of all this, we also consider a scenario where the optical emission from HS 0822+3542 comes not from two merging ultra-compact dwarfs but from multiple star-forming regions in a tidally disturbed galaxy. In this model, the ocular appearance of the brighter star-forming region could be the result of triggered star formation.