Miracle-dz/UniFAR-FTUs huggingface dataset:
Design and characterization of a research electrohydraulic lithotripter patterned after the Dornier HM3

An electrohydraulic lithotripter has been designed that mimics the behavior of the Dornier HM3 extracorporeal shock wave lithotripter. The key mechanical and electrical properties of a clinical HM3 were measured and a design implemented to replicate these parameters. Three research lithotripters have been constructed on this design and are being used in a multi-institutional, multidisciplinary research program to determine the physical mechanisms of stone fragmentation and tissue damage in shock wave lithotripsy. The acoustic fields of the three research lithotripters and of two clinical Dornier HM3 lithotripters were measured with a PVDF membrane hydrophone. The peak positive pressure, peak negative pressure, pulse duration, and shock rise time of the focal waveforms were compared. Peak positive pressures varied from 25 MPa at a voltage setting of 12 kV to 40 MPa at 24 kV. The magnitude of the peak negative pressure varied from 2 7t o212 MPa over the same voltage range. The spatial variations of the peak positive pressure and peak negative pressure were also compared. The focal region, as defined by the full width half maximum of the peak positive pressure, was 60 mm long in the axial direction and 10 mm wide in the lateral direction. The performance of the research lithotripters was found to be consistent at clinical firing rates ~up to 3 Hz! The results indicated that pressure fields in the research lithotripters are equivalent to those generated by a clinical HM3 lithotripter. © 2000 American Institute of Physics. @S0034-6748~00! 01806-2#
Hydrodynamics of bacterial colonies

Understanding the growth and dynamics of bacterial colonies is a fascinating problem, which requires combining ideas from biology, physics and applied mathematics. We briefly review the recent experimental and theoretical literature relevant to this question and describe a hydrodynamic model (Lega and Passot 2003 Phys. Rev. E 67 031906, 2004 Chaos 14 562–70), which captures macroscopic motions within bacterial colonies, as well as the macroscopic dynamics of colony boundaries. The model generalizes classical reaction–diffusion systems and is able to qualitatively reproduce a variety of colony shapes observed in experiments. We conclude by listing open questions about the stability of interfaces as modelled by reaction–diffusion equations with nonlinear diffusion and the coupling between reaction–diffusion equations and a hydrodynamic field.
Use of basic color terms by red–green dichromats: 1. General description

: In this article we present data comparing red–green dichromats' use of “Basic Color Terms” (BCTs) with that of standard trichromats. In a complementary article (Color Res Appl 2013) we use these data to evaluate two models of the mechanisms underlying dichromats' use of BCTs. There were three groups of observers—trichromats, protanopes, and deuteranopes—that each performed two tasks: “mapping” (which of these are exemplars of X? ) and “best exemplar” (which is the best instance of X? ), where X took the value of each Spanish BCT. The mapping task results were subjected to multidimensional scaling that revealed that dichromats differ from trichromats in the number and nature of the dimensions needed for describing BCTs' use. Trichromats required three dimensions closely related to the opponent color mechanisms (red–green, yellow–blue) and the light-dark channel. In contrast, tridimensional solution for dichromats was difficult to interpret, whereas the fit for the bidimensional solution was very good and revealed a chromatic dimension, which did not match any of the trichromatic dimensions, and an achromatic one. There were also some error-asymmetries (sometimes “A” was the predominant error when choosing exemplars of “B”, but not vice versa) and the groups differed in the frequency of use of some BCTs (e.g., protanopes chose more stimuli as orange than trichromats and deuteranopes). As expected, the best exemplar task produced more correct responses than the mapping task, and for both tasks, “primary” BCTs (black, white, red, green, yellow, and blue) produced better results than “derived” ones (brown, purple, orange, pink, and grey). © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 360–371, 2014
Partial λ-Geometries and Generalized Hadamard Matrices Over Groups

Section 1 of this paper contains all the work which deals exclusively with generalizations of Hadamard matrices. The non-existence theorem proven here (Theorem 1.10) generalizes a theorem of Hall and Paige [15] on the non-existence of complete mappings in certain groups. In Sections 2 and 3, we consider the duals of (Hanani) transversal designs; these dual structures, which we call (s, r, µ)-nets, are a natural generalization of the much studied (Bruck) nets which in turn are equivalent to sets of mutually orthogonal Latin squares. An (s, r, µ)-net is a set of s 2 µ points together with r parallel classes of blocks. Each class consists of s blocks of equal cardinality. Two non-parallel blocks meet in precisely µ points. It has been proven that r is always less than or equal to (s 2 µ – l) / (s – 1).
Approximations to ruin probability in the presence of an upper absorbing barrier

Abstract Segerdahl (1970) considered a risk process with two absorbing barriers using methods which led to exact solutions for only particular claim amount distributions. The present paper develops an alternative method for exact solutions for ruin probabilities in the presence of an absorbing upper barrier and, by using an embedded Markov chain, obtains numerical approximations for such ruin probabilities for any claim amount distribution. Refinements to the approximating procedure are discussed. Comparison of exact ruin probabilities, when they can be identified, with the corresponding numerical approximations provides a measure of the accuracy of the method. Sensitivity of the method to changes in parameters is illustrated. When explicit exact solutions to ruin probabilities cannot be obtained, it appears likely that accurate approximations can be obtained by the Markov chain approach with less computational effort than is required to carry out numerical solution of the equation(s) for the exact value.
Birefringence measurement under hydrostatic pressure utilizing twist-induced effects in highly birefringent fibers

A new method of birefringence measurement in highly birefringent bow-tie fibers under hydrostatic pressure up to 100 MPa is presented. The birefringence measurement method is based on twist-induced effects and has never been applied before in a high-pressure environment. The experiments were conducted using a specially designed pressure facility, which made it possible to simultaneously generate several mechanical. Perturbations, including twist and hydrostatic stress, and to investigate their effects on mode transmission in optical fibers. The results indicate that in the case of ECB single-mode bow-tie fibers, hydrostatic pressure up to 100 MPa decreased beat length with a mean coefficient of 1/L/sub Bo/|dL/sub Bdp|=0.170%/MPa what is in a very close agreement with our previous measurement based on Rayleigh scattering. <<ETX>>
Three-dimensional flow measurements induced from serpentine plasma actuators in quiescent air

This paper presents three-dimensional flow measurements performed on a dielectric barrier discharge (DBD) actuator with the electrodes in a serpentine design. Such a configuration induces a local pinching and a local spreading of the fluid as one follows along the span of the actuator. In this work two different variations on the serpentine configuration are evaluated: one constructed from patterned circular arcs and one from patterned rectangles. The influence of applied voltage is studied for the former case. To quantify these effects stereo particle image velocimetry (PIV) is used to generate time averaged, spatially resolved measurements of the detailed flow structure. The three components of the velocity vector are measured along spanwise and streamwise cuts. These slices are then reconstructed to provide a three-dimensional view of the induced flow field. The results for the induced flow fields are also compared with stereo-PIV measurements made on a standard linear DBD actuator. A truly three-dimensional induced flow field was observed as a result of the serpentine configuration. These designs could be beneficial for rapid mixing of the local fluid.
Wavelet-based uniformity of plasma etching surface

Uniformity of plasma etching has been conventionally examined only in terms of etch rate. A uniformity of etching profile surface is increasingly demanded to improve process quality. This is accomplished by applying a discrete wavelet transformation (DWT) to profile images obtained with a scanning electron microscopy. Applicability of DWT-based profile uniformity was evaluated with a tungsten etch experiment, conducted in an SF/sub 6/ helicon plasma. Its suitability was investigated as a function of process parameters and scale levels. Compared to a conventional metric, the wavelet-based one characterized more effectively the uniformity of profile variations. The proposed metric can be applied to any other plasma-processed surfaces.
Collisional excitation of sulfur dioxide in cold molecular clouds

We present collisional rate coefficients for SO2 with ortho and para molecular hydrogen for the physical conditions prevailing in dark molecular clouds. Rate coefficients for thefirst 31 rotational levels of this species (energies up to 55 K) and for temperatures between 5 and 30 K are provided. We have found that these rate coefficients are about ten times more than those previously computed for SO2 with helium. We calculated the expected emission of the centimeter wavelength lines of SO2. We find that the transition connecting the metastable 202 level with the 111 one is in absorption against the cosmic background for a wide range of densities. The 404−313 line is found to be inverted for densities below a few 10 4 cm −3 . We observed the 111−202 transition with the 100 m Green Bank Telescope towards some dark clouds. The line is observed, as expected, in absorption and provides an abundance of SO2 in these objects of af ew 10 −10 . The potential use of millimeter lines of SO2 as tracers of the physical conditions of dark clouds is discussed.
Asymptotically optimal methods for sequential change-point detection

This thesis studies sequential change-point detection problems in different contexts. Our main results are as follows: - We present a new formulation of the problem of detecting a change of the parameter value in a one-parameter exponential family. Asymptotically optimal procedures are obtained. - We propose a new and useful definition of ? asymptotically optimal to first-order? procedures in change-point problems when both the pre-change distribution and the post-change distribution involve unknown parameters. In a general setting, we define such procedures and prove that they are asymptotically optimal. - We develop asymptotic theory for sequential hypothesis testing and change-point problems in decentralized decision systems and prove the asymptotic optimality of our proposed procedures under certain conditions. - We show that a published proof that the so-called modified Shiryayev-Roberts procedure is exactly optimal is incorrect. We also clarify the issues involved by both mathematical arguments and a simulation study. The correctness of the theorem remains in doubt. - We construct a simple counterexample to a conjecture of Pollak that states that certain procedures based on likelihood ratios are asymptotically optimal in change-point problems even for dependent observations.
General Kinematical Solution to the Motion of an Explosively Driven Liner

It is shown that the motion of an explosively driven smooth thin liner, obeys, whenever the material forces are negligible, the following equation: where V is the liner velocity, ∂Vl/∂t is the time derivative of the velocity component along the liner direction and l is the Lagrangian coordinate measuring the length of the liner contour (formation line). The transformation from the rest to moving coordinate system is calculated, as well as a very accurate approximation to the liner elongation. Under the assumption of an exponential acceleration a closed form for the liner elongation is obtained. The influence of the liner curvature on the projection angle δ is also found. The comparison of the obtained solution with two dimensional Lagrangian code calculations shows a very good agreement. Finally, some predictions of the model are discussed for demonstrating its applicability to various problems.
Constellation space invariance of space-time block codes with application to optimal antenna subset selection

We prove a new constellation space invariance property of space-time block codes (STBC) based on generalized orthogonal designs. In the flat block-fading channel case, it is shown that the internal structure of the vector space of the input constellation remains invariant to the combined effect of the STBC and the channel, except for a scaling factor. Using the established property, we prove that the exact error probability of the maximum likelihood (ML) decoder is a decreasing function of the Frobenius norm of the channel matrix in the general case when the channel, STBC, and input signal constellations are arbitrary. The constellation space invariance property is then applied to the problem of antenna subset selection in multiple-input multiple-output (MIMO) systems. We study the popular norm-based antenna subset selection method which is known to minimize an upper bound on the pairwise probability of error at the output of the ML decoder. The strict optimality of this approach is established by proving that it minimizes the exact probability of error as well.
Comparison of Sm II transition probabilities

This Research Note provides a comparison of experimental atomic transition probabilities in Sm~II from two recent publications. Basic data of this type for rare-earth spectra, including Sm~II, are very difficult to determine using ab-initio theoretical methods. Experimental programs are underway in several laboratories to determine these data for ongoing astrophysical studies of the origins of the chemical elements. The two recent and nearly simultaneous publications, which were based on very different experimental methods, provide transition probabilities in good, but not perfect, agreement.PACS Nos.: 32.70. Cs, 32.70. Fw, 32.30. Jc
New Features of X‐Ray Bragg Diffraction Topography with Coherent Illumination

New features of the X-ray Bragg diffraction topography with coherent beam and third generation synchrotron radiation sources are described. An experimental set-up for coherent topography is proposed and used to record images from practically perfect substrates, namely a thin SiO 2 film on an InP substrate, and the scratches on the surface of a Si crystal. It is shown that very weak localized deformations can produce contrast up to 70%. Some theoretical estimations to reveal the performance of the proposed technique are made.
Flash flood forecasting: What are the limits of predictability?

Flash floods may occur suddenly and be accompanied by other hazards such as landslides, mud flows, damage to infrastructure and even death. In the UK such events are comparatively rare occurring on average only once or twice per year. Warning systems must depend upon the accurate real‐time provision of rainfall information, high‐resolution numerical weather forecasts and the operation of hydrological model systems in addition to forecast delivery procedures not discussed in this paper. In this paper we review how flash floods are forecast considering the limitations and uncertainty involved in both the meteorological and hydrological aspects of forecasting systems. Data assimilation and the use of ensembles are both key elements across disciplines. Assessing the susceptibility of river catchments to extreme flooding is considered, and statistical methods of estimating the likelihood of extreme rainfall and floods within a changing climate are examined. Ways of constraining flash flood forecasts are noted as one way to improve forecast performance in the future. Copyright © 2007 Royal Meteorological Society
Nonlinear waves and turbulence in Marangoni convection

In the paper we present a numerical study of a new type of nonlinear waves in Marangoni convection. The waves are caused by nonlinear interaction between long‐scale deformational instability and short‐scale convection. It is shown that, due to a nonlinear coupling with the deformation of the free liquid–gas interface, the primary convection pattern can undergo oscillatory instability generating various kinds of long surface waves which modulate the short‐scale convection. The numerical analysis of the system of nonlinear coupled equations describing these waves confirms the predictions of weakly nonlinear analysis and shows the existence of either standing or travelling waves in the proper parametric regions, at low supercriticality. With increasing supercriticality, the waves undergo various transformations leading to the formation of pulsating travelling waves, aharmonic standing waves as well as irregular wavy behavior resembling ‘‘interfacial turbulence. ’’ We map regions in the parameter space where v.
On the weakly nonlinear development of Tollmien-Schlichting wavetrains in boundary layers

The nonlinear development of a weakly modulated Tollmien-Schlichting wavetrain in a boundary layer is studied theoretically using high-Reynolds-number asymptotic methods. The ‘carrier’ wave is taken to be two-dimensional, and the envelope is assumed to be a slowly varying function of time and of the streamwise and spanwise variables. Attention is focused on the scalings appropriate to the so-called ‘upper branch’ and ‘high-frequency lower branch’. The dominant nonlinear effects are found to arise in the critical layer and the surrounding ‘diffusion layer’: nonlinear interactions in these regions can influence the development of the wavetrain by producing a spanwise-dependent mean-flow distortion. The amplitude evolution is governed by an integro-partial-differential equation, whose nonlinear term is history-dependent and involves the highest derivative with respect to the spanwise variable. Numerical solutions show that a localized singularity can develop at a finite distance downstream. This singularity seems consistent with the experimentally observed focusing of vorticity at certain spanwise locations, although quantitative comparisons have not been attempted.
Energy levels of point defects in SrTiO3 and related oxides

The energy levels of defects in SrTiO3, PbTiO3 and PbZrO3 have been calculated by the tight-binding Greens function method and compared to experiment. This method is very useful for displaying the chemical trends in defect energy levels. The Ti and O vacancies are found to be shallow. Transition metal impurities at the octahedral ion site are found to give rise to numerous charge states because of the large intra-atomic electron repulsion. The levels are generally in the high spin configuration, except for the high valence transition metals. The levels of Cr4+, Fe4+, and Co4+ lie near midgap. The Ti3+ trapped electron centers become deep at higher Zr contents in Pb(Zr,Ti)O3.
Precursory Changes in Planetary Wave Activity for Midwinter Surface Pressure Anomalies over the Arctic

The development of surface pressure anomalies observed in January over the Arctic is investigated based on composite analysis of observed data. The monthly anomalies in January with a high degree of zonal symmetry are found to extend from the surface into the lower stratosphere, in a manner similar to the Arctic Oscillation (AO). The formation of the AO-like signature in January tends to follow the strengthening/weakening of upward propagation of planetary waves in November over the western portion of Eurasia, where temperature anomalies associated with a train of external Rossby waves modify the thermal structure of the climatological planetary waves. In the lower stratosphere the external Rossby wavepacket also modulates meridional winds associated with the climatological planetary waves, augmenting upward propagations of the planetary waves. Thus, modulated upward propagation of the planetary waves subsequently changes the intensity of the stratospheric polar vortex, leading to the formation of the stratospheric AO-like signals and their downward extension. This study presents an example in which regional modifications in the structures of the upward-propagating planetary waves due to a zonally-confined external Rossby wave train can change the intensity of the stratospheric polar vortex, which may possibly prolong the predictability of seasonal climate anomalies in the Arctic and surrounding regions.
An Exact Solution of Mie Type for Scattering by a Multilayer Anisotropic Sphere

The purpose of this paper is to describe methods of resolving discrepancies between experimental observations of scattering by crystalline particles and attempts to explain these observations assuming that the electrical properties of these particles can be described by the use of scalar valued functions for the permittivity, conductivity, and permeability. We can develop coupled integral equations describing the interaction of electromagnetic radiation with a heterogeneous, penetrable, dispersive, anisotropic scatterer and can use several methods of solving these integral equations. The solution of the problem of describing scattering by an anisotropic sphere can be substituted into the integral equation to check the integral equation formulation of the problem. Conditions are given for the uniqueness of the solution of the associated transmission problem. Because of the multiple propagation constants in an anisotropic material, the trivial uniqueness arguments valid for isotropic scatterers do not have .
A sublinear time string prefix square detection algorithm

Abstract In this paper, an algorithm is proposed to detect the occurrence of a prefix square concurrently when a string is inputted. Some properties of certain variables are studied in order to show the correctness and the time complexity of this algorithm. The time complexity of this algorithm is proved to be not only linear but also sublinear.
Adaptive inference for multi-stage unbalanced exponential survey data

Two-stage sampling usually leads to higher variances for estimators of means andregression coecients, because of intra-cluster homogeneity. One way of allowing forclustering in tting a linear regression model is to use a linear mixed model with twolevels. If the estimated intra-cluster correlation is close to zero, it may be acceptableto ignore clustering and use a single level model. In this paper, an adaptive strategy isevaluated for estimating the variances of estimated regression coecients. The strategyis based on testing the null hypothesis that random eect variance component is zero. Ifthis hypothesis is accepted the estimated variances of estimated regression coecientsare extracted from the one-level linear model. Otherwise, the estimated variance isbased on the linear mixed model, or, alternatively the Huber-White robust varianceestimator is used. A simulation study is used to show that the adaptive approachprovides reasonably correct inference in a simple case.