Miracle-dz/UniFAR-FTUs huggingface dataset:
RANDOM PARTICLE MODEL FOR FRACTURE OF AGGREGATE OR FIBER COMPOSITES

A particle model for brittle aggregate composite materials such as concretes, rocks, or ceramics is presented. The model is also applicable to the behavior of unidirectionally reinforced fiber composites in the transverse plane. A method of random computer generation of the particle system meeting the prescribed particle size distribution is developed. The particles are assumed to be elastic and have only axial interactions, as in a truss. The interparticle contact layers of the matrix are described by a softening stress‐strain relation corresponding to a prescribed microscopic interparticle fracture energy. Both two‐ and three‐dimensional versions of the model are easy to program, but the latter poses, at present, forbidding demands for computer time. The model is shown to simulate realistically the spread of cracking and its localization. Furthermore, the model exhibits a size effect on: (1) The nominal strength, agreeing with the previously proposed size effect law; and (2) the slope of the post‐peak l.
On the intrinsic two-dimensionality of the CSF and its measurement

Classically the visual system sensitivity has been studied separately as a function of spatial frequency and orientation, without explicitly pointing out the relation between both parameters. As the visual system processes two-dimensional signals, its Contrast Sensitivity Function (CSF) is intrinsically two-dimensional too, and therefore, the dependence of the 1-D CSF on orientation is obtained by considering different radial profiles of the 2-D CSF. In the present work, we study the simplest and most straightforward method to obtain the maximum amount of information about the 2-D CSF with a minimum of measurements. It follows from the results that, for emmetropic observers, it is enough to measure two perpendicular radial profiles of the CSF to obtain enough information about the whole 2-D frequency domain, where as for the most common astigmatism cases, it's necessary to include another intermediate measure. Assuming that the Modulation Transfer Function (MTF) is proportional to the CSF, it's possible to compute the visual system Point Spread Function (PSF), optical and neural parts, from the function experimentally obtained. To estimate the accuracy of the method, the 2-D PSF is calculated and, we simulate, by computer, the perception of a test using the 2-D CSF measured for emmetropic and astigmatic observers.
SYNTHESIS AND CHARACTERIZATION CHITOSAN FILM WITH SILVER NANOPARTICLE ADDITION AS A MULTIRESISTANT ANTIBACTERIAL MATERIAL

The synthesis of chitosan films with the addition of silver nanoparticles (AgNps) has been carried out in 2 stages. The first stage is to make colloidal silver nanoparticles with chitosan as a stabilizer and a reducing agent with NaOH as an accelerator and assisted by microwave irradiation. The second stage is to make a film from colloidal silver nanoparticles-chitosan by casting method. The formation of silver nanoparticles was identified using a UV-Vis spectrophotometer and Transmission electron microscopy (TEM). Chitosan films with the addition of AgNps were characterized by chemical, physical and mechanical properties. Furthermore, the antibacterial activity was tested against E. Coli ATCC, S. Aureus ATCC and multi-resistant bacteria ESBL and MRSA. The results showed that the formation of AgNps was indicated by the appearance of an absorption band at 400-413 nm with a size of less than 6 nm. The FTIR spectra showed that there was a slight shift at the 1604 cm-1 peak which indicated that the AgNps interacted with the NH 2 group on D-glucosamine of chitosan. The films morphology with addition Ag NPs tends to be rough in surface and cross-sectional. The presence of AgNps tends to increase the swelling value, tensile strength and film elasticity. Chitosan film with the addition of silver nanoparticles has antibacterial activity against multi-resistant bacteria ESBL and MRSA. The antibacterial activity of the film was derived solely from the silver nanoparticles.
A Bivariate Bayes Method for Improving the Estimates of Mortality Rates With a Twofold Conditional Autoregressive Model

A bivariate Bayes method is proposed for estimating the mortality rates of a single disease for a given population, using additional information from a second disease. The information on the two diseases is assumed to be from the same population groups or areas. The joint frequencies of deaths for the two diseases for given populations are assumed to have a bivariate Poisson distribution with joint means proportional to the population sizes. The relationship between the mortality rates of the two different diseases if formulated through the twofold conditional autoregressive (CAR) model, where spatial effects as well as indexes of spatial dependence are introduced to capture the structured clusterings among areas. This procedure is compared to a univariate hierarchical Bayes procedure that uses information from one disease only. Comparisons of two procedures are made by the optimal property, a Monte Carlo study, real data, and the Bayes factor. All of the methods that we consider demonstrate a substantial improvement in the bivariate over the univariate procedure. For analyzing male and female lung cancer data from the state of Missouri, Markov chain Monte Carlo methods are used to estimate mortality rates.
Representation-theoretic support spaces for finite group schemes

We introduce the space P ( G ) of abelian p -points of a finite group scheme over an algebraically closed field of characteristic p 0. We construct a homeomorphism Ψ G : P ( G ) → Proj | G | from P ( G ) to the projectivization of the cohomology variety for any finite group G . For an elementary abelian p -group (respectively, an infinitesimal group scheme), P ( G ) can be identified with the projectivization of the variety of cyclic shifted subgroups (resp., variety of 1-parameter subgroups). For a finite dimensional G -module M , Ψ G restricts to a homeomorphism P ( G ) M → Proj | G | M , thereby giving a representation-theoretic interpretation of the cohomological support variety.
Custom Hardware Processor to Compute a Figure of Merit for the Fit of X-Ray Diffraction Peaks

A custom processor based on reconfigurable hardware technology is proposed in order to compute the figure of merit used to measure the quality of the fit of X-ray diffraction peaks. As the experimental X-ray profiles can present many peaks severely overlapped, it is necessary to select the best model among a large set of reasonably good solutions. Determining the best solution is computationally intensive, because this is a hard combinatorial optimization problem. The proposed processors, working in parallel, increase the performance relative to a software implementation.
OSNR enhancement utilizing large effective area fiber in a multiwavelength Brillouin-Raman fiber laser

We propose a simple Brillouin-Raman multi-channel fiber laser with supportive Rayleigh scattering in a linear cavity without employing any feedback mirrors at the end of cavity. Brillouin and the consequences of Rayleigh scattering work as virtual mirrors. We employ a section of large effective area fiber in addition to a section of dispersion compensating fiber to enhance the optical signal-to-noise ratio of multi-channel Brillouin-Raman comb fiber laser. We able to produce a flat comb fiber laser with 37 nm bandwidth from 1539 to 1576 nm built-in 460 Stokes lines with 0.08 nm spacing. Furthermore, this Brillouin-Raman comb fiber laser has acceptable optical signal-to-noise ratio value of 16.8 dB for the entire bandwidth with excellent flatness and low discrepancies in power levels of about 2.3 dB between odd and even channels.
Interband Quantum Kinetics with LO-Phonon Scattering in a Laser-Pulse-Excited Semiconductor I. Theory

Nonequilibrium Green's function theory is employed to derive with the use the generalized Kadanoff-Baym ansatz quantum kinetic equations for the interband polarization and the densities of electrons and holes. These equations are valid in the regime of ultrafast spectroscopy, where that usual Boltzmann kinetics with its individual energy-conserving collisions no longer holds. The memory kernel of the retarded quantum kinetic equations is determined by retarded and advanced Green's functions. It is stressed and explicitly shown by numerical solutions in an adjacent paper that these Green's functions have to be approximated consistently with the coupling to phonons
Wave activity and baroclinic stability theorems for a two‐dimensional stratified semi‐geostrophic model

Arnold's method is used to derive two finite‐amplitude wave‐activity invariants – pseudo‐momentum and pseudo‐energy – based on the Hamiltonian structure for the two‐dimensional baroclinic semi‐geostrophic (SG) model in physical coordinates. The corresponding Liapunov stability theorems are established. For small‐amplitude disturbances the pseudo‐momentum and pseudo‐energy can be greatly simplified by introducing the quasi‐potential‐vorticity perturbation. The corresponding linear stability conditions, expressed explicitly in terms of the basic state, are obtained. The lateral boundary conditions are found to have a big impact on the stability of SG dynamics in both linear and nonlinear cases.
Tracked robot controllers for climbing obstacles autonomously

Research in mobile robot navigation has demonstrated some success in navigating flat indoor environments while avoiding obstacles. However, the challenge of analyzing complex environments to climb obstacles autonomously has had very little success due to the complexity of the task. Unmanned ground vehicles currently exhibit simple autonomous behaviours compared to the human ability to move in the world. This paper presents the control algorithms designed for a tracked mobile robot to autonomously climb obstacles by varying its tracks configuration. Two control algorithms are proposed to solve the autonomous locomotion problem for climbing obstacles. First, a reactive controller evaluates the appropriate geometric configuration based on terrain and vehicle geometric considerations. Then, a reinforcement learning algorithm finds alternative solutions when the reactive controller gets stuck while climbing an obstacle. The methodology combines reactivity to learning. The controllers have been demonstrated in box and stair climbing simulations. The experiments illustrate the effectiveness of the proposed approach for crossing obstacles.
Strained Si, SiGe, and Ge channels for high-mobility metal-oxide-semiconductor field-effect transistors

This article reviews the history and current progress in high-mobility strained Si, SiGe, and Ge channel metal-oxide-semiconductor field-effect transistors (MOSFETs). We start by providing a chronological overview of important milestones and discoveries that have allowed heterostructures grown on Si substrates to transition from purely academic research in the 1980’s and 1990’s to the commercial development that is taking place today. We next provide a topical review of the various types of strain-engineered MOSFETs that can be integrated onto relaxed Si1−xGex, including surface-channel strained Si n- and p-MOSFETs, as well as double-heterostructure MOSFETs which combine a strained Si surface channel with a Ge-rich buried channel. In all cases, we will focus on the connections between layer structure, band structure, and MOS mobility characteristics. Although the surface and starting substrate are composed of pure Si, the use of strained Si still creates new challenges, and we shall also review the litera.
Molecular-level control of polymer/nanocrystal interface towards efficient hybrid solar cells

Colloidal narrow bandgap semiconductor nanocrystals are regarded as attractive components in hybrid organic/inorganic composites for solution-processed photovoltaic applications. However, solar cells comprising polythiophene conjugated polymers and lead chalcogenide nanocrystals, which are among the most commonly used materials for photovoltaics, have been considered inefficient as a result of poor charge separation from the hybrid interface. Here we demonstrate that tailoring the nanocrystal surface chemistry drastically impacts the morphology and optoelectronic properties of composites based on poly(3-hexylthiophene) and lead sulfide nanocrystals, promoting long-lived charge separation and enabling the fabrication of bulk-heterojunction solar cells which display an outstanding thousand-fold enhancement of the power conversion efficiency, reaching 3 %. We thus provide a simple yet powerful strategy to gain control over the optoelectronic properties of hybrid composites by tailoring the organic/inorganic interface at the nanoscale, suggesting a reliable path to further improve the efficiency of polymer/nanocrystal solar cells.
On normal numbers.

A number f is called simply normal in the scale of r if (1) holds for k = 1. A number is said to be absolutely normal if it is normal to every base r. It is well-known (see, for example, [6], Theorem 8.11) that almost every number ξ is absolutely normal. We write r ^ s, if there exist integers n, m with r — s. Otherwise, we put r Φ s. In this paper we solve the following problem. Under what conditions on r, s is every number ξ which is normal to base r also normal to base s ? The answer is given by
The cause and cure (!) of the spurious pressures generated by certain fem solutions of the incompressible Navier‐Stokes equations: Part 2

SUMMARY The spurious pressures and ostensibly acceptable velocities which sometimes result from certain FEM approximate solutions of the incompressible Navier-Stokes equations are explained in detail. The concept of pressure modes, physical and spurious, pure and impure, is introduced and their effects on discretized solutions is analysed, in the context of both mixed interpolation and penalty approaches. Pressure filtering schemes, which are capable of recovering useful pressures from otherwise polluted numerical results, are developed for two particular elements in two-dimensions and one element in three-dimensions. The automatic pressure filter associated with the penalty method is also explained. Implications regarding the effect of spurious pressure modes on accuracy and ultimate convergence with mesh refinement are discussed and a list of unanswered questions presented. Sufficient numerical examples are discussed to corroborate the theory presented herein.
NOTES AND CORRESPONDENCE An Analytic Longwave Radiation Formula for Liquid Layer Clouds

Many Global Energy and Water Cycle Experiment (GEWEX) Cloud System Study (GCSS) intercomparisons of boundary layer clouds have used a convenient but idealized longwave radiation formula for clouds in their large-eddy simulations (LESs). Under what conditions is this formula justified? Can it be extended to midlevel layer clouds? This note first derives the GCSS formula using an alternative method to effective emissivity. A key simplifying assumption is that the cloud is isothermal in the vertical (and horizontal). However, this assumption does not turn out to be overly restrictive in practice. Then the GCSS formula is compared with a detailed numerical code, BugsRad. Sensitivity studies are performed in which cloud properties, cloud altitude, and thermodynamic profiles are modified. Here, the focus is primarily on midlevel, altostratocumulus layers. The results here show that the GCSS formula can be successfully extended to liquid (ice free), midlevel clouds. The GCSS formula produces remarkably accurate radiative profiles if the parameters are adjusted on a case-by-case basis. However, the formula needs to be calibrated using a more general radiative transfer code.
Optical characterization of pancreatic normal and tumor tissues with double integrating sphere system

In order to develop minimally invasive, fast and precise diagnostic and therapeutic methods in medicine by using optical methods, first step is to examine how the light propagates, scatters and transmitted through medium. So as to find out appropriate wavelengths, it is required to correctly determine the optical properties of tissues. The aim of this study is to measure the optical properties of both cancerous and normal ex-vivo pancreatic tissues. Results will be compared to detect how cancerous and normal tissues respond to different wavelengths. Double-integrating-sphere system and computational technique inverse adding doubling method (IAD) were used in the study. Absorption and reduced scattering coefficients of normal and cancerous pancreatic tissues have been measured within the range of 500-650 nm. Statistical significant differences between cancerous and normal tissues have been obtained at 550 nm and 630 nm for absorption coefficients. On the other hand; there were no statistical difference found for scattering coefficients at any wavelength.
Increasing the Power of Nonparametric Tests by Detecting and Downweighting Outliers

Abstract In this study, methods are examined that can be described, somewhat paradoxically, as robust nonparametric statistics. Although nonparametric tests effectively control the probability of Type I errors through rank randomization, they do not always control the probability of Type II errors and power, which can be grossly inflated or deflated by the shape of distributions. The power of the Student t test and the Wilcoxon-Mann-Whitney test declines substantially when samples are obtained from outlier-prone densities, including mixed-normal, Cauchy, lognormal, and mixed-uniform densities. However, the nonparametric test acquires an advantage, because outliers influence the t test to a relatively greater extent. Under these conditions, an outlier detection and downweighting (ODD) procedure, usually associated with parametric significance tests, augments the power of both the t test and the Wilcoxon-Mann-Whitney test.
CLASSIFICAÇÃO HÍBRIDA: PIXEL A PIXEL E BASEADA EM OBJETOS PARA O MONITORAMENTO DA CONDIÇÃO DA SUPERFÍCIE DOS PAVIMENTOS RODOVIÁRIOS

Monitorar a condicao de uso de toda a extensao das rodovias brasileiras e tarefa dispendiosa e demorada. Este trabalho trata de novas tecnicas que permitem o levantamento da condicao da superficie dos pavimentos rodoviarios de forma agil utilizando imagens hiperespectrais de sensor digital aeroembarcado. Nos ultimos anos, um numero crescente de imagens de alta resolucao espacial tem surgido no mercado mundial com o aparecimento dos novos satelites e sensores aeroembarcados de sensoriamento remoto. Propoe-se uma metodologia para identificacao dos pavimentos asfalticos e classificacao das principais ocorrencias dos defeitos na superficie do pavimento. A primeira etapa da metodologia e a identificacao da superficie asfaltica na imagem, utilizando uma classificacao hibrida baseada inicialmente em pixel e depois refinada por objetos. A segunda etapa da metodologia e a identificacao e classificacao das ocorrencias dos principais defeitos nos pavimentos flexiveis que sao observaveis nas imagens de alta resolucao espacial. Esta ultima etapa faz uso intensivo das novas tecnicas de classificacao de imagens baseadas em objetos. O resultado final e a geracao de indices da condicao da superficie do pavimento a partir das imagens que possam ser comparados com os indicadores vigentes da condicao da superficie do pavimento ja normatizados pelos orgaos competentes no pais
A Hybrid Nonlinear Conjugate Gradient Method with Sufficient Descent Property

In this paper, on the basis of the recently developed HZ (Hager-Zhang) method [SIAM J. Optim. , 16 (2005), pp. 170-192], we propose a hybrid descent conjugate gradient method which reserves the sufficient descent property of the HZ method. Under suitable conditions, we prove the global convergence of the proposed method. Extensive numerical experiments show that the method is promising for the test problems from the CUTE library.
X-ray fluorescence from the inner disc in Cygnus X-1

Les spectres RX de nombreuses sources de trous noirs en accretion suggerent la presence de matiere relativement froide entouree d'un plasma emetteur de RX dur. Les raies fluorescentes du fer sont produites par l'irradiation RX du gaz froid. On montre que la raie d'emission large du fer trouvee dans Cyg X-1 par Barr P., White N.E. et Page C.G. (1985, Mon. Not. R. astr. Soc., 216) est bien modelisee par une emission fluorescente emanant des parties internes d'un disque d'accretion
Influence of Base Slant on the Wake Structure and Drag of Road Vehicles

The time averaged wake structure of a realistically dimensioned quarter scale automobile model was studied in a wind tunnel on the basis of flow visualization, wake surveys, force and pressure measurements. Through a systematic variation of base slant angle in the range of 0 to 40 deg, the ensuing changes in the wake structure were observed and the wake structure present at lowest value of aerodynamic drag is shown. Experimental data were obtained at a model length based Reynolds number of 4.29 million. Correlation of wake structure with drag, pressure distribution, and kinetic energy content of vortex motion in wake is addressed.
Quantum Gravity: A Primer for Philosophers

‘Quantum Gravity’ does not denote any existing theory: the field of quantum gravity is very much a ‘work in progress’. As you will see in this chapter, there are multiple lines of attack each with the same core goal: to find a theory that unifies, in some sense, general relativity (Einstein’s classical field theory of gravitation) and quantum field theory (the theoretical framework through which we understand the behaviour of particles in non-gravitational fields). Quantum field theory and general relativity seem to be like oil and water, they don’t like to mix—it is fair to say that combining them to produce a theory of quantum gravity constitutes the greatest unresolved puzzle in physics. Our goal in this chapter is to give the reader an impression of what the problem of quantum gravity is; why it is an important problem; the ways that have been suggested to resolve it; and what philosophical issues these approaches, and the problem itself, generate. This review is extremely selective, as it has to be to remain a manageable size: generally, rather than going into great detail in some area, we highlight the key features and the options, in the hope that readers may take up the problem for themselves—however, some of the basic formalism will be introduced so that the reader is able to enter the physics and (what little there is of) the philosophy of physics literature prepared. I have also supplied references for those cases where I have omitted some important facts. Hence, this chapter is intended primarily as a catalyst for future research projects by philosophers of physics, both budding and well-matured.
On Introducing Asymmetry into Circular Distributions

We give a brief history of the results which led to the introduction of asymmetry into symmetric circular distributions. This is followed by the presentation of another method of introducing asymmetry. Some properties of the induced distributions are studied. Finally, this new distribution is shown to be a reasonable fit to the Jander ant data as presented in Fisher (1993).