Miracle-dz/UniFAR-FTUs huggingface dataset:
Enhancement of Convective Precipitation by Mesoscale Variations in Vegetative Covering in Semiarid Regions

Abstract It is hypothesized that planting bands of vegetation with widths of the order of 50–100 km in semiarid regions could, under favorable large-scale atmospheric conditions, result in increases of convective precipitation. These increases, which could be greater than those associated with the uniform vegetating of large areas, would occur through three major mechanisms. The first would be the modification of the environment to a state more conducive to the formation of moist convection through an increase of low-level moist static energy. This increase would be associated with a decrease in albedo, an increase in net radiation, and an increase in evapotranspiration. The second important mechanism would be the generation of mesoscale (horizontal scale of 20–200 km) circulations associated with the surface inhomogeneities created on this scale by the vegetation. The third mechanism would be the increase of atmospheric water vapor through decreased runoff and increased evaporation. A number of observati.
Measuring BRDF using a single still digital camera

BRDF (Bidirectional Reflective Distribution Function)is broadly used in many fields, such as physics, heat transformation, remote sensing, and computer graphics. Traditional methods to measure BRDF are expensive for most peoples, and image based approach becomes a novel direction. Until now, for such an image based system, at least a video camera and a still camera are indispensible, and the operations are not easily carried out under a convenient condition. In this paper, a method using only one still camera is proposed, with the help of a light source, a cylinder support, and a sphere. The material to be measured is painted on the sphere, putting on the cylinder support painted with BRDF- known material. Around the cylinder support, a simple control points nets are distributed. In the measurement process, the light source and the support are fixed, operators goes around the sphere to obtain pictures at different view angles and the rest work is finished automatically by a set of programs. The pictures are first processed by a photogrammetric program to get the geometry in the scene, including the positions, directions, and the shapes of light source, the support, the sphere, and the cameras. The BRDF samples are calculated from the image intensity and the obtained geometric relations, which are approximated by a multivariable spline to get a full BRDF description. Three different materials are tested with the method.
Wind Tunnel Study of Turbulent Flow Structure in the Convective Boundary Layer Capped by a Temperature Inversion

Abstract Experiments on simulating the atmospheric convective boundary layer (CBL), capped by a temperature inversion and affected by surface shear, were carried out in the thermally stratified wind tunnel of the Institute of Hydrology and Water Resources, University of Karlsruhe. The tunnel is of the closed-circuit type, with a test section 10 m long, 1.5 m wide, and 1.5 m high. The return section of the tunnel is subdivided into 10 layers, each driven by its own fan and heating system. By this means, velocity and temperature profiles can be preshaped at the inlet of the test section, which allows for the reproduction of developed CBL over comparatively short fetches. The bottom heating is controlled to produce the constant heat flux through the floor of the test section. The flow velocity components in the tunnel are measured with a laser Doppler system; for temperature measurements, the resistance-wire technique is employed. A quasi-stationary, horizontally evolving CBL was reproduced in the tunnel, wi.
Cross-phase modulation between lasers in a tunnel ionizing gas

The phase modulation of a low power long pulse probe laser beam in a rapidly tunnel ionizing gas (helium) under a relativistic short pulse laser is investigated. The relativistic pulse creates a fast increasing plasma density at its front, far ahead of the intensity peak. The probe pulse sees these changes as modulation in its phase and undergoes large frequency upshift. The spectral content of the blueshifted potion of the probe pulse is large when its intensity peak commoves with the ionization front. There are two ionization front created by first and second ionizations, and the separation between the two increases as laser propagates through the gas. The rate of density variation by first and second ionizations, however, is fairly the same and varies little as the spot size of the laser beam increases up to three times its initial value. The ionization front velocity, as well as the upshift in probe pulse frequency, is bigger for sharper laser pulse.
Randomness Through Computation: Some Answers, More Questions

This review volume consists of a set of chapters written by leading scholars, most of them founders of their fields. The volume is intended to explain the phenomenon of Randomness through the use of Computation, and to explore the connections of Randomness to other areas of scientific knowledge, especially its fruitful relationship to Computability and Complexity Theory, and also to areas such as Probability, Statistics, Information Theory, Biology, Physics, Quantum Mechanics, Learning Theory and Artificial Intelligence. The contributors cover these topics without neglecting important philosophical dimensions, sometimes going beyond the purely technical to formulate age old questions relating to matters such as determinism and free will. The scope of Randomness Through Computation is novel. Each contributor shares their personal views and anecdotes on the various reasons and motivations which led them to the study of Randomness. Using a question and answer format, they share their visions from their several distinctive vantage points.
Investigation of light amplification by enhanced internal reflection. Part II. Experimental determination of the single-pass reflectance of an optically pumped gain region

We have measured as a function of incident angle, for a range of critical angles between 88° and 89° and of characteristic gain depths between 41 and 96 probe wavelengths, the single-pass reflectance of a He–Ne probe beam reflected from a transverse optically pumped solution of rhodamine B. In contrast to previously reported experiments, no anomalously high reflectances were observed. The theoretical formulas for the exponentially nonuniform-gain model reproduce well the observed reflectance curves including the locations, slopes, and heights of the amplification maximum in the vicinity of critical angle. Peak amplifications of 200–300% were predicted and observed for the given experimental conditions.
Initial observations with the Solwind coronagraph

Since 1979 March 28 a new NRL coronagraph called ''Solwind'' has been observing the Sun's outer corona (2.6--10.0 R/sub sun/) routinely with a spatial resolution of 1'. 25 and a temporal resolution of 10 minutes. These are the first satellite observations of the outer corona near the peak of a sunspot cycle, when coronal transients and high-latitude streamers are expected to be common. Coronal variations on time scales from 10 minutes to 27 days are revealed dramatically in easily constructed gray-scale difference images.
The effect on the evolution of the drop spectrum in clouds of the preconditioning of air by successive convective elements

A multiple air-parcel model is used to study the effect on the drop size spectrum inside convective clouds of preconditioning of air by successive convective elements. Numerical evaluation of this model shows that each rising air parcel establishes a new environment for the air parcel following it, thus substantially affecting its thermodynamic behaviour. This preconditioning of air allows successive air parcels to penetrate an inversion and produce precipitation-sized drops under conditions which are not conducive to precipitation when only a single air parcel is considered.
Breast imaging with the SoftVue imaging system: first results

For women with dense breast tissue, who are at much higher risk for developing breast cancer, the performance of mammography is at its worst. Consequently, many early cancers go undetected when they are the most treatable. Improved cancer detection for women with dense breasts would decrease the proportion of breast cancers diagnosed at later stages, which would significantly lower the mortality rate. The emergence of whole breast ultrasound provides good performance for women with dense breast tissue, and may eliminate the current trade-off between the cost effectiveness of mammography and the imaging performance of more expensive systems such as magnetic resonance imaging. We report on the performance of SoftVue, a whole breast ultrasound imaging system, based on the principles of ultrasound tomography. SoftVue was developed by Delphinus Medical Technologies and builds on an early prototype developed at the Karmanos Cancer Institute. We present results from preliminary testing of the SoftVue system, performed both in the lab and in the clinic. These tests aimed to validate the expected improvements in image performance. Initial qualitative analyses showed major improvements in image quality, thereby validating the new imaging system design. Specifically, SoftVue’s imaging performance was consistent across all breast density categories and had much better resolution and contrast. The implications of these results for clinical breast imaging are discussed and future work is described.
In situ manipulation and electrical characterization of multiwalled carbon nanotubes by using nanomanipulators under scanning electron microscopy

The results of in situ manipulation and electrical transport characterization of individual multiwalled carbon nanotubes (MWCNTs) grown on a nickel tip by using a piezoelectric nanomanipulation system operating in a scanning electron microscope chamber have been reported. The growth of MWCNT directly on nickel wire by chemical vapor deposition technique ensures good electrical contact with the catalyst substrate. Using the electron beam induced welding, a full characterization of electronic properties of several MWCNTs has been explored without the usual postprocessing methods which may alter, in principle, the intrinsic properties of the carbon nanotube (CNT). Thanks to the high mechanical and electrical stability ensured by the electron beam welding procedure, a detailed study of the modification of CNT electrical transport properties under CNT buckling has been performed. The crucial role played by the structural defects in determining an irreversibility of a long MWCNT $I\text{\ensuremath{-}}V$ characteristic under mechanical stress has been clearly evidenced. Finally, by a proper sequence of CNT/tip welding and movement, the potential in creating an Ohmic junction between two nanotubes has been demonstrated, opening the route to a systematic investigation of one of the most fundamental aspect of CNT physics.
Probabilistic Forecast Guidance for Severe Thunderstorms Based on the Identification of Extreme Phenomena in Convection-Allowing Model Forecasts

AbstractWith the advent of convection-allowing NWP models (CAMs) comes the potential for new forms of forecast guidance. While CAMs lack the required resolution to simulate many severe phenomena associated with convection (e.g., large hail, downburst winds, and tornadoes), they can still provide unique guidance for the occurrence of these phenomena if “extreme” patterns of behavior in simulated storms are strongly correlated with observed severe phenomena. This concept is explored using output from a series of CAM forecasts generated on a daily basis during the spring of 2008. This output is mined for the presence of extreme values of updraft helicity (UH), a diagnostic field used to identify supercellular storms. Extreme values of the UH field are flagged as simulated “surrogate” severe weather reports and the spatial correspondence between these surrogate reports and actual observed severe reports is determined. In addition, probabilistic forecasts [surrogate severe probabilistic forecasts (SSPFs)] are .
Exploiting multimode waveguides for pure fibre based fluorescence imaging

There has been an immense drive in modern microscopy towards miniaturisation and _bre based technology. This has been necessitated by the need to access hostile or difficult environments particulalrly in-situ and in-vivo. Strategies to date have included the use of specialist fibres and miniaturised scanning systems accompanied by ingenious microfabricated lenses. In parallel recent studies of randomized light fields and their holographic control opened up new ways for imaging. We present a novel approach for this field by utilising disordered light within a standard multimode optical fibre for minimally invasive lenseless microscopy and optical mode conversion. We demonstrate scanning uorescence microscopy at acquisition rates allowing observation of dynamic processes such as Brownian motion of mesoscopic particles. As the sample plane can be defined at any distance from the fibre facet, we eliminate the need for complex or elaborate focusing optics (e.g. miniaturized objectives, GRIN lenses) and instead reconfigure the system dynamically to image different axial planes. Furthermore, we show how such control can realise a new form of mode converter and generate various types of advanced light fields such as propagation-invariant beams and optical vortices. These may be useful for future fibre based implementations of super-resolution or light sheet microscopy. To the best of our knowledge, this technology represents the narrowest possible image guiding system based on light propagation.
The Rochester gravitational wave detector

The authors present the first detailed report of the Rochester cryogenic resonant gravitational wave detector. They believe that the approach used in designing the detector will bring substantial contributions to the solutions of many unsolved problems. They describe in detail their transducer which makes use of several features (superconducting, wideband, noncontacting) in a unique combination that already has made it possible to achieve the highest mechanical Q for aluminum in a gravitational wave detector (Q=2*107). They also present encouraging results of preliminary tests and they calculate the values of the physical parameters needed to achieve a competitive ultimate sensitivity. They show how reasonable parameters lead to such sensitivity, even though the detecting mass is smaller than what is commonly used. The authors explain why dealing with a smaller mass presents important advantages. Finally they include a detailed analysis of the sensitivity and a description of the procedure for the calibration.
Evolution of ECMWF sub‐seasonal forecast skill scores

Sub‐seasonal forecasts have been routinely produced at ECMWF since 2002 with reforecasts produced ‘on the fly’ to calibrate the real‐time sub‐seasonal forecasts. In this study, the skill of the reforecasts from April 2002 to March 2012 and covering a common set of years (1995 to 2001) has been evaluated. Results indicate that the skill of the ECMWF reforecasts to predict the Madden–Julian Oscillation (MJO) has improved significantly since 2002, with an average gain of about 1 day of prediction skill per year. The amplitude of the MJO has also become more realistic, although the model still tends to produce MJOs which are weaker than in the ECMWF re‐analysis. As a consequence, the ability of the ECMWF model to simulate realistic MJO teleconnections over the Northern and Southern Extratropics has improved dramatically over the 10‐year period. Forecast skill scores have also improved in the Extratropics. For instance, weekly mean forecasts of the North Atlantic Oscillation Index are more skilful in recent years than 10 years ago. A large part of this improvement seems to be linked to the improvements in the representation of the MJO. Skill to predict 2 m temperature anomalies over the Northern Extratropics has also improved almost continuously since 2002. Changes in the horizontal and vertical resolutions of the atmospheric model had only a small impact on the skill scores, suggesting that most of the improvements in the ECMWF sub‐seasonal forecasts were due to changes in model physics which were primarily designed to improve the model climate and medium‐range forecasts. The impact of changes in the data assimilation system and in the observing data has not been considered in this study, since all the reforecasts used for this study were initialized from the same re‐analysis over a common set of years.
Detection of built-up area in optical and synthetic aperture radar images using conditional random fields

Abstract Classifying built-up areas from satellite images is a challenging task due to spatial and spectral heterogeneity of the classes. In this study, a contextual classification method based on conditional random fields (CRFs) has been used. Spatial and spectral information from blocks of pixels were employed to identify built-up areas. The CRF association potential was based on support vector machines (SVMs), whereas the CRF interaction potential included a data-dependent term using the inverse of the transformed Euclidean distance. In this way, accuracy was stable for a varying smoothness parameter, while preserving class boundaries and aggregating similar labels, and a discontinuity adaptive model was obtained and conditioned on data evidence. The classification was applied on satellite towns around the city of Nairobi, Kenya. The accuracy exceeded that of Markov random fields, SVM, and maximum likelihood classification by 1.13%, 2.22%, and 8.23%, respectively. The CRF method had the lowest fraction of false positives. The study concluded that CRFs can be used to better detect built-up areas. In this way, it provides accurate timely spatial information to urban planners and other professionals.
Hybrid Simulation Approach for Cavity Flows: Blending, Algorithm, and Boundary Treatment Issues

The maturation of high-performance computer architectures and computational algorithms has prompted the development of a new generation of models that attempt to combine the robustness and efficiency offered by the Reynolds averaged Navier-Stokes equations with the higher level of modeling offered by the equations developed for large eddy simulation. The application of a new hybrid approach is discussed, where the transition between these equation sets is controlled by a blending function that depends on local turbulent flow properties, as well as the local mesh spacing. The utilization of local turbulence properties provides added control in specifying the regions of the flow intended for each equation set, removing much of the burden from the grid-generation process. Moreover, the model framework allows for the combination of existing closure model equations, avoiding the difficulty of formulating a single set of closure coefficients that perform well in both Reynolds averaged and large eddy simulation modes. Simple modifications to common second-order accurate Reynolds averaged Navier-Stokes algorithms are proposed to enhance the capturing of large eddy motions
Target selection using a utility theoretic approach

Modern target tracking systems perform different tasks among which are target detection, selection and tracking. In this study, we describe a target selection technique based on Utility Theory. The utility of each target is assumed to be a linear combination of some basis functions that act on certain features of the target such as size, intensity, speed and direction. The unknown parameters of the basis functions and their weights are selected using a descent type optimization technique. Simulation results are presented.
Design, deposition, and characterization of multilayer mirrors for ultrashort pulses in the attosecond domain

We present the design, the optimization and the realization of multilayer mirrors for the transport and the compression of attosecond pulses generated by high harmonics emission from 35 eV to 55 eV. At wavelength characterizations have been performed on an attosecond source. We explore also the phase determination of the complex reflectivity from photon-electron emission measurement on synchrotron beamline.
High performance optically pumped antimonide lasers operating in the 2.4–9.3μm wavelength range

We provide an update on the further development of optically pumped semiconductor lasers based on the InAs∕InGaSb∕InAs type-II quantum wells. We show increased power generation, as well as the inherent flexibility to produce devices that can emit at any wavelength in the ∼2. 4μm to ∼9. 3μm range with consistently high photon-to-photon conversion rates.
Efficiency optimization of interior permanent magnet synchronous motor using genetic algorithms

This paper presents an optimal design method to maximize the efficiency of the interior permanent magnet synchronous motor. To do this, the efficiency of the motor is taken as the objective function, and the genetic algorithm is used as the optimization algorithm to find the optimal design variables of the objective function. To make a more accurate prediction of performance possible, the air gap flux density and d, q axis inductances obtained by an analytical method are compensated by using the results from FEM studies.
Scattering from three-dimensional objects embedded in multilayered media

This paper presents a model for computing the scattered field of a three dimensional scatterer embedded in multilayered media. The embedded object is modeled using a volume integral equation approach which allows the handling of general inhomogeneous objects. THe multilayered media is modeled using a transmission line analogy. The scattered field is obtained by obtaining the equivalent current sources in the discretization elements of the object. The convolution-form of the volume integral formulation allows the use of the conjugate gradient FFT computation method which is essential for reducing the memory storage requirements. Formulations are presented for scattering from an object in free space, a scatterer on top of a perfectly conducting surface and a scatterer embedded in multilayered media. The Green's function of the integral equation has two parts: a free space primary part and a secondary part due to the layered media. The secondary Green's function is in the form of Sommerfeld's integration which commonly has a fast oscillating integrand. Different techniques are presented to overcome this difficulty. This includes using an asymptotic solution using the stationary phase method and real axis integration. Results are presented for scattering from a sphere as an example of the object.
Methods of Mathematical Physics

Partial table of contents: THE ALGEBRA OF LINEAR TRANSFORMATIONS AND QUADRATIC FORMS. Transformation to Principal Axes of Quadratic and Hermitian Forms. Minimum-Maximum Property of Eigenvalues. SERIES EXPANSION OF ARBITRARY FUNCTIONS. Orthogonal Systems of Functions. Measure of Independence and Dimension Number. Fourier Series. Legendre Polynomials. LINEAR INTEGRAL EQUATIONS. The Expansion Theorem and Its Applications. Neumann Series and the Reciprocal Kernel. The Fredholm Formulas. THE CALCULUS OF VARIATIONS. Direct Solutions. The Euler Equations. VIBRATION AND EIGENVALUE PROBLEMS. Systems of a Finite Number of Degrees of Freedom. The Vibrating String. The Vibrating Membrane. Green's Function (Influence Function) and Reduction of Differential Equations to Integral Equations. APPLICATION OF THE CALCULUS OF VARIATIONS TO EIGENVALUE PROBLEMS. Completeness and Expansion Theorems. Nodes of Eigenfunctions. SPECIAL FUNCTIONS DEFINED BY EIGENVALUE PROBLEMS. Bessel Functions. Asymptotic Expansions. Additional Bibliography. Index.