Miracle-dz/UniFAR-FTUs huggingface dataset:
Principles of operation of the rubidium vapor magnetometer

This paper discusses some of the basic problems involved in designing and using a magnetometer employing optical pumping. Particular attention is given to magnetometers of the self-oscillating type; i.e., those that are analogous to masers in that the resonant properties of the spin system itself are used to sustain continuous oscillation at the resonant frequency. Among the topics treated are amplitude variations with orientation, sensitivity, behavior in extremely weak magnetic fields, and response to rapid field changes.
Parabolic MongeAmpre Equations on Riemannian Manifolds

On a compact Riemannian manifold (M, g) we consider the parabolic Monge–Ampere equation∂∂tϕ(x,t)=logdet(g(x)+Hessϕ(x,t))detg(x)−λϕ(x,t)−f(x)ϕ(x,0)=phiv;0(x). Hereλis a real parameter andf, ϕ0: M→R are smooth functions. We show existence ofϕfor all timestindependent ofλ. Ifλ>0, thenϕt=ϕ(·, t) converges exponentially towards a solutionϕ∞of the stationary problem ast→∞. In the special caseλ>0, f=0 one hasϕ∞=0 and we determine the convergence rateϕt→ϕ∞in theL2-norm more precisely.
Effects of various axial flow profiles on the magneto-Rayleigh-Taylor instability in Z-pinch implosions

The stabilizing effect of different axial flow profiles on the magneto-Rayleigh-Taylor (MTR) instability in Z-pinch implosions is investigated with a compressible skin-current model. The numerical results show that the mitigation effect of the axial flow on the MRT instability is caused by the radial velocity shear, and it is highly susceptible to the shear value nearby the plasma outer surface. By adjusting the flow profile, the mitigation effect can be improved markedly.
An infrared quintuplet near the Galactic center

A compact cluster of five luminous infrared sources has been found in the vicinity of the Galactic center radio arc. All of the sources have large polarizations in the near-infrared and deep silicate absorptions at 10 microns. Strong absorption lines of CO are seen at 4.6 microns toward each source. The observed polarization and spectral features are likely to be interstellar in origin. The temperatures of the sources, based on infrared photometry and corrected for extinction, are in the range 600-900 K. None of the sources show either infrared recombination line emission from atomic hydrogen, lines of molecular hydrogen, or overtone band of CO at 2.3 microns. Because the objects are tightly clustered, all are likely to be very young objects; however, accurate classifications cannot be made at the present time. 31 refs.
A study of the electrical charging of the Rosetta orbiter: 2. Experimental tests in a laboratory plasma

[1] Following the numerical simulation presented in the companion paper, we have performed experimental tests in a plasma simulation chamber to check the results of the numerical model and validate its capability to properly predict the electrical equilibrium of the Rosetta orbiter. Since low temperature cometary plasmas cannot be directly reproduced in such a chamber, we conducted the tests in plasmas with scaled characteristics deduced by considering similarity laws as is done in wind tunnel experiments. A mock-up of the Rosetta orbiter and solar panels was constructed with the capability of measuring collected currents over the various faces of the mock-up. These measurements included the possibility of observations on finer scales typical of ion collection as measured by ion energy analysers. This series of tests has allowed us to validate the performances and the predictions of the model presented in the companion paper.
Mesoscale Convective Systems in Weakly Forced Large-Scale Environments. Part II: Generation of a Mesoscale Initial Condition

Abstract A series of five mesoscale convective systems (MCSs) developed within a weakly forced large-scale environment on 11 and 12 May 1982. Two of these systems had a large component of motion against the midtroposphoric flow and propagated in a direction nearly opposite to that of the traveling upper-level disturbances. This description of the evolution of convection is very different from traditional ones in which convection develops and moves more or less in phase with traveling upper-level disturbances. Observations indicate that the initiation and evolution of convection are tied to mesoscale features that are not well observed by the conventional observing network, making the structure of the model initial condition a potentially crucial factor in the success or failure of any subsequent numerical simulation. It is found that the initial conditions created using the conventional initialization procedure of The Pennsylvania State University-National Center for Atmospheric Research Mesoscale Model d.
Nonlinear optical response of As+‐ion implanted GaAs studied using time resolved reflectivity

The transient reflectivity response of GaAs with a 2% excess As concentration (GaAs:As), prepared by As+ ion implantation, has been measured at photon energies near the band gap. Results are compared with similar measurements on implanted GaAs with a 0.01% excess As concentration, and unimplanted GaAs. For GaAs:As, the transient refractive index change Δn, is larger than, but of the opposite sign to that of unimplanted GaAs. The measured carrier lifetime of 1±0.1 ps is identical to that of low‐temperature GaAs. The wavelength dependence of Δn indicates the presence of an induced absorption peak at photon energies near the band gap, which is attributed to band‐gap renormalization.
Current-carrying properties in a low resistivity state for Ag-sheathed Bi2Sr2CuCu2O8 tape

In high temperature superconductors, a low resistivity state is quite stable from a viewpoint of power application. When a low resistivity state instead of the superconductivity with zero resistance is concentrated on, a current-carrying limitation before thermal runaway has to be investigated for high temperature superconductors. We have examined the thermal runaway parameters related to the heat transfer coefficient and the matrix resistivity for Ag-sheathed Bi2Sr2CaCu2O8 tape. The calculated parameters were evaluated in comparison with the experimental results obtained under the cryocooling condition.
Cosmic Radiation and Cosmic Magnetic Fields. II. Origin of Cosmic Magnetic Fields

The equations governing the behavior of a wholly or partly ionized gas moving in the presence of a magnetic field are given. It is emphasized that the electric conductivity is independent of the magnetic field strength in many cases of actual interest. The stationary case of a magnetic field arising from the nonrigid rotation of a gaseous body is considered. Such a field is of the toroidal type. Fields of poloidal type may arise by the contraction of magnetized interstellar matter towards a star. The increase of strength of a magnetic field in turbulent conducting matter (stellar or interstellar) is considered. The conclusion is reached that the turbulence of every order of magnitude leads finally to a magnetic field, the energy density of which corresponds roughly to the energy density of the turbulence considered. If the magnetic field was weak in the beginning, this state was reached at first by the turbulence of smallest scale and smallest velocity, and then by the turbulence of higher orders; hence, the magnetic field strength must change secularly, as long as this process goes on. If our galaxy had only weak fields in its earlier stages, the present magnetic field should correspond to the turbulent velocity associated with distances of the order of ${10}^{3}$ light years (between ${10}^{\ensuremath{-}6}$ and ${10}^{\ensuremath{-}5}$ gauss), and these fields should be more or less homogeneous over distances of this order. If there were already fields in the beginning, the present fields might be somewhat stronger.
A Model of Drizzle Growth In Warm, Turbulent, Stratiform Clouds

A model to describe the growth of precipitation sized drops in layers of warm, stratiform cloud is developed which combines the effects of stochastic turbulent diffusion with explicit microphysical calculations. the representation of diffusion is consistent with measured turbulence statistics, reproduces standard results and is used to define an ensemble of Lagrangian trajectories within which the effects of phase change, stochastic coalescence and vertical exchange due to gravitational settling can be calculated. Mean drop size distributions are predicted as functions of height within the cloud. The inclusion of realistic levels of turbulence is found to produce greatly increased numbers of larger (r >100 μm) drops throughout the depth of the cloud. the modelled steady-state drop size distributions show good agreement with corresponding aircraft measurements in a case study. the effects of changing the turbulence intensity, cloud depth and liquid water content on the distribution of larger drops are investigated and implications for the cloud layer water balance and the cloud radiative properties are also considered.
Super free fall

The free fall of a liquid mass through vertical tubes with a weakly increasing cross-section induces an acceleration of the upper liquid interface larger than gravity. The phenomenon is well described by a one-dimensional inviscid model. The super acceleration of the upper interface comes from the additional positive pressure gradient caused by the expanding geometry, which adds to the gravity body force. A perturbative expansion of this base solution further accounts for the interface shape and stability. In particular, the positive pressure gradient at the interface makes it unstable, forming a concentrated ‘nipple’ on top of the essentially flat base solution. We discuss the possible connexion of these findings with the problem of wave breaking in free surface flows.
Numerov’s Method with Deferred Corrections for Two-Point Boundary-Value Problems

The iterated deferred correction of the standard fourth-order equally spaced finite-difference (Numerov’s or Cowell’s) method for second-order two-point boundary-value problems is implemented by an improved version of the codes developed by Pereyra. The improvements are of a general nature so as to be applicable to the deferred correction of other basic schemes. Results of numerical experiments are summarized.
Unsteady bubble propagation in a flexible channel: predictions of a viscous stick-slip instability

We investigate the unsteady motion of a long bubble advancing under either prescribed pressure $p_{\rm b}$ or prescribed volume flux $q_{\rm b}$ into a fluid-filled flexible-walled channel at zero Reynolds number, an idealized model for the reopening of a liquid-lined lung airway. The channel walls are held under longitudinal tension and are supported by external springs; the bubble moves with speed $U$. Provided $p_{\rm b}$ exceeds a critical pressure $p_{\rm crit}$, the system exhibits two types of steady motion. At low speeds, the bubble acts like a piston, slowly pushing a column of fluid ahead of itself, and $U$ decreases with increasing $p_{\rm b}$. At high speeds, the bubble rapidly peels the channel walls apart and $U$ increases with increasing $p_{\rm b}$. Using two independent time-dependent simulation techniques (a two-dimensional boundary-element method and a one-dimensional asymptotic approximation), we show that with prescribed $p_{\rm b}\,{>}\,p_{\rm crit}$, peeling motion is stable and the steady pushing solution is unstable; for $p_{\rm b}\,{<}\,p_{\rm crit}$ the system ultimately exhibits unsteady pushing behaviour for which $U$ continually diminishes with time. When $q_{\rm b}$ is prescribed, peeling motion (with large $q_{\rm b}$) is again stable, but pushing motion (with small $q_{\rm b}$) loses stability at long times to a novel instability leading to spontaneous relaxation oscillations of increasing amplitude and period, for which the bubble switches abruptly between slow unsteady pushing and rapid quasi-steady peeling. This stick–slip motion is characterized using a third-order lumped-parameter model which in turn is reduced to a nonlinear map. Implications for the inflation of occluded lung airways are discussed.
Analysis of a finite element method for Maxwell's equations

The use of finite elements to discretize the time dependent Maxwell equations on a bounded domain in three-dimensional space is analyzed. Energy norm error estimates are provided when general finite element methods are used to discretize the equations in space. In addition, it is shown that if some curl conforming elements due to Nedelec are used, error estimates may also be proved in the $L^2 $ norm.
Feasibility Study and Preliminary Results of Prognostic Value of Bone SPECT-CT Quantitative Indices for the Response Assessment of Bone Metastatic Prostate Carcinoma to Abiraterone

Objective: We assessed the prognostic value of quantitative indices extracted from bone SPECT-CT to evaluate the response of bone metastatic castrate-resistant prostate cancer (BmCRPC) to abiraterone. Methods: Consecutive patients with BmCRPC initiating treatment with abiraterone from March 2014 to March 2015 were prospectively included. Three 2-bed SPECT-CT [at baseline [M0], after 3 months [M3], and 6 months [M6] of treatment], were planned (Symbia Intevo®, Siemens). SPECT data were reconstructed using an Ordered Subset Conjugate Gradient Minimization (OSCGM) algorithm allowing SUV quantification. SUVmax and SUVpeak of the highest uptake lesion were measured in each SPECT-CT. Total Neoplastic Osteoblastic Metabolic Volume (NOMV) was assessed. PSA level was recorded at baseline, M3, and M6 of treatment. Overall survival (OS), progression-free survival (PFS), and disease-specific survival (DSS) were calculated. Results: Nineteen patients aged 71.1 ± 7.7 years were included. Low M0 SUVmax was significantly predictive of longer OS (p = 0.04). Low NOMV at M0 were significantly predictive of longer PFS (p = 0.02). Patients with increase of at least 12.5% of the SUVpeak of the highest uptake lesion between M0 and M3 (ΔSUVpeakM0M3) had a significantly longer OS (p = 0.03). Patients with increase (or decrease lesser than 25%) of ΔSUVpeakM0M3 had a significantly longer DSS (p = 0.01). Patients with increase of NOMV of at least 45% between M0 and M6 had a significantly shorter PFS (p < 0.001). Variations of NOMV between M0 and M6 were significantly correlated with PSA variations between M0 and M6 (rs = 0.73, p = 0.02). Conclusions: Quantitative bone SPECT-CT appears to be a promising tool of BmCRPC assessment. Early flare-up phenomenon seems to predict longer OS.
Final Report of CCPR-K3.b.2-2004: Bilateral Comparison of Illuminance Responsivity Scales between the KRISS (Korea) and the HUT (Finland)

A bilateral comparison of illuminance responsivity scales between the KRISS and the HUT was carried out, where the HUT acted as the pilot and link to the key comparison CCPR-K3.b. The ratio of the measured illuminance responsivities (KRISS/HUT) was 0.9982, with expanded uncertainty of 0.0060 (k = 2) including the uncertainty of the comparison and the uncertainties of the realization of the scales. Main text. To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database kcdb.bipm. org/. The final report has been peer-reviewed and approved for publication by the CCPR, according to the provisions of the Mutual Recognition Arrangement (MRA).
Inference to the Best Explanation Made Coherent

Van Fraassen (1989) argues that Inference to the Best Explanation is incoherent in the sense that adopting it as a rule for belief change will make one susceptible to a dynamic Dutch book. The present paper argues against this. A strategy is described that allows us to infer to the best explanation free of charge.
On the Volume of the Intersection of Two L n p Balls

This note deals with the following problem, the case $p=1$, $q=2$ of which was introduced to us by Vitali Milman: What is the volume left in the $L_p^n$ ball after removing a t-multiple of the $L_q^n$ ball? Recall that the $L_r^n$ ball is the set $\{(t_1,t_2,\dots,t_n);\ t_i\in{\bf R},\ n^{-1}\sum_{i=1}^n|t_i|^r\le 1\}$ and note that for $0<p<q<\infty$ the $L_q^n$ ball is contained in the $L_p^n$ ball. In Corollary 4 we show that, after normalizing Lebesgue measure so that the volume of the $L_p^n$ ball is one, the answer to the problem above is of order $e^{-ct^pn^{p/q}}$ for $T<t<{1\over 2}n^ {{1\over p}-{1\over q}}$, where $c$ and $T$ depend on $p$ and $q$ but not on $n$. The main theorem, Theorem 3, deals with the corresponding question for the surface measure of the $L_p^n$ sphere.
Combined Effects of Mold Deformation and Shell Thermal Capacity on Growth Instability During Unidirectional Solidification of Pure Metals

ABSTRACT Previous models of thermomechanically induced freezing front growth instability have neglected either the mold distortion or the thermal capacitance of the solidifying shell material. While these assumptions are useful in providing insight into solidification thermomechanics, they fail to account for the combined effects of the mold deformation and the thermal capacity of the shell material. In this paper, growth instability during solidification of pure metals is reexamined under the assumption that the shell material with nonnegligible thermal capacitance solidifies on a deformable mold with a mean finite thickness. The mold is assumed to have infinitely large thermal diffusivity, and a sinusoidal surface microgeometry for which the ratio of the amplitude to the wavelength in much less than one. This makes the aspect ratio a convenient perturbation parameter. The contact pressure in the troughs of the mold surface is calculated for different mold-shell material combinations that consist of pure copper, aluminum, or iron. The influence of mold surface wavelength and mean contact pressure on shell growth is examined for these cases. The effects of mold thickness on gap nucleation times for selected wavelengths are investigated. The role of the thermal capacitance of the solidifying shell material when combined with thermoelastic distortion of the mold is examined through qualitative comparisons between results from the present model and those from previous models. Conclusions are drawn about the relative significance of these factors on the unstable growth of the shell thickness. Communicated by Jim Barber on February 16, 2005.
A three‐dimensional finite element method with arbitrary polyhedral elements

The ‘variable‐element‐topology finite element method’ (VETFEM) is a finite‐element‐like Galerkin approximation method in which the elements may take arbitrary polyhedral form. A complete development of the VETFEM is given here for both two and three dimensions. A kinematic enhancement of the displacement‐based formulation is also given, which effectively treats the case of near‐incompressibility. Convergence of the method is discussed and then illustrated by way of a 2D problem in elastostatics. Also, the VETFEM's performance is compared to that of the conventional FEM with eight‐node hex elements in a 3D finite‐deformation elastic–plastic problem. The main attraction of the new method is its freedom from the strict rules of construction of conventional finite element meshes, making automatic mesh generation on complex domains a significantly simpler matter. Copyright © 2006 John Wiley & Sons, Ltd.
A Method for the Solution of the Distribution Problem of Stochastic Linear Programming

A method is proposed for finding a closed form expression for the cumulative distribution function (CDF) of the maximum value of the objective function in a stochastic linear programming problem in the case where either the objective function coefficients or the right-hand side coefficients are given by known probability distributions. If the objective function coefficients are random, the CDF is obtained by integrating over the space for which a given feasible basis remains optimal. A transformation is presented using the Jacobian theorem which simplifies the regions of integration and often simplifies the integration itself. A similar analysis is presented in the case where the right-hand side coefficients are random. An example is given to illustrate the technique.
Nuclear fission viewed as a diffusion process: Case of very large friction

Using a Fokker-Planck equation, we consider induced nuclear fission for large values of the friction constant. Then, the equation simplifies to the Smoluchowski equation which we solve using a method of van Kampen. We find that the fission rate obeys a scaling law. From our numerical results and those obtained previously, we estimate the transient time tau for fission. For small nuclear temperature, tau is defined as the time delay between the onset of a nuclear reaction and the attainment of the quasistationary probability flow over the fission barrier. For nuclear temperatures large compared to the fission barrier, the entire fission process is governed by transients, and tau essentially yields the fission lifetime. We speculate on the significance of our results for recent experimental observations.
A low-bit-rate audio codec using mel-scaled linear predictive analysis

In this paper, we propose a low-bit-rate audio codec using a new analysis method named mel-scaled linear predictive analysis (mel-LP analysis). In mel-LP analysis, a spectral envelope is estimated on a mel- or bark-frequency scale, so as to improve the spectral resolution in the low-frequency band. This analysis is accomplished with about a twofold increase in computation over standard LPC analysis. Our codec using mel-LP analysis consists of five key parts: time frequency transformation, flattening of MDCT coefficients using the mel-LP spectral envelope, power normalization, perceptual weighting estimation, and multistage VQ. In subjective experiments, we investigated the performance of our codec using the mel-LP analysis method, through 7-level paired comparison tests. The result shows that the codec using the mel-LP analysis method results in a good performance at a low bit rate, particularly at 16kbps. In the cases of pop songs, piano music and male speech, sound quality was improved.
Significance Tests in Parallel and in Series

Abstract The advice is often given that significance tests should be selected before sampling evidence is examined. It is suggested here that this advice is appropriate only for inexperienced statisticians, and an approximate rule of thumb is tentatively proposed in the hope of provoking discussion, namely that the statistician could in some cases use a harmonic mean or weighted harmonic mean of the tail-area probabilities arising from various tests, all on the same evidence (tests in “parallel”). This rule of thumb should not be used if the statistician can think of anything better to do, and especially of course if he is in a position to use a sufficient statistic (or an “efficacious” one, in a sense defined below). An application is given to the judgment of the weights that may be used for combining tests in series.
Effects of the lower boundary on the head of a gravity current

Experimental measurements of the advancing head of a gravity current are described. The head, of depth d in mean cross-section and advancing at mean speed U, has an elevated nose whose mean height h satisfies h/d = 0·61 Re-0·23±0·01 through the range 300 < Re < 10000 (Re = Ud/ν). A shifting pattern of lobes and clefts ranges across the head, in which the mean lobe width $\overline{b}$ is found experimentally to satisfy $\overline{b}/d = 7.4\,Re^{-0.39\pm 0.02}$. By moving the floor in the direction of the current, or by introducing a thin dense layer beneath it, the lobes and clefts can be suppressed and a purely two-dimensional flow obtained. It is concluded that the lower boundary plays an essential role in determining the substructure of the head and that this originates in convective instability as the head rides over less dense fluid.