Miracle-dz/UniFAR-FTUs huggingface dataset:
Size Matters : The Vacuum System of the KATRIN Neutrino Experiment

The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to measure the electron neutrino mass with an unprecedented sensitivity of 0.2 eV/c2, using β-electrons from tritium decay. Super-conducting magnets will guide the electrons through a vacuum beam-line from the gaseous tritium source through a differential pumping section to a high resolution spectrometer, where the kinetic energy will be measured. This paper will give an overview of the complex vacuum system of the KATRIN experiment and presents first results of the vacuum performance of the spectrometer. Background considerations require a vacuum of 10-11 mbar or better in the large spectrometer vessel (1240 m3). A combination of NEG pumps and cascaded turbo-molecular pumps will provide the necessary pumping speed. First measurements of outgassing rates after baking the stainless steel vessel (316LN) at 350°C are reported here.
A no-reference video quality assessment metric based on ROI

A no reference video quality assessment metric based on the region of interest (ROI) was proposed in this paper. In the metric, objective video quality was evaluated by integrating the quality of two compressed artifacts, i.e. blurring distortion and blocking distortion. The Gaussian kernel function was used to extract the human density maps of the H.264 coding videos from the subjective eye tracking data. An objective bottom-up ROI extraction model based on magnitude discrepancy of discrete wavelet transform between two consecutive frames, center weighted color opponent model, luminance contrast model and frequency saliency model based on spectral residual was built. Then only the objective saliency maps were used to compute the objective blurring and blocking quality. The results indicate that the objective ROI extraction metric has a higher the area under the curve (AUC) value. Comparing with the conventional video quality assessment metrics which measured all the video quality frames, the metric proposed in this paper not only decreased the computation complexity, but improved the correlation between subjective mean opinion score (MOS) and objective scores.
Sound Generated by Fan Wakes and Validation with Experiments

This paper presents a validation of the rotor-wake/stator interaction code, CAAT-S, with NASA Source Diagnostic Test (SDT) experiments. CAAT-S is a computationally efficient three-dimensional code based on the Euler equations linearized about a nonlinear rotational mean flow. It accounts for the flow swirl, the blade and fan 3D geometry and loading, and yields directly the radiated sound in terms of the duct acoustic modes. Two exit guide vane configurations, three power levels, and three blade passing frequencies (BPF) are considered. The power levels presented are taken at approach, cutback, and takeoff conditions for (a) the SDT low vane count (LVC) stator and (b) the SDT low noise (LN) stator. The mean flow and wake profiles are taken from the SDT experiments and exhibit strong radial dependencies. The reduced frequencies, based on the blade tip and speed of sound, associated with SDT data range from 15 for the 1BPF at approach power to 72 for 3 BPF at takeoff power. This produces a large number of propagating acoustic modes and makes the prediction of the vane forces and the radiated sound power a real computational challenge. Improved nonreflecting boundary conditions are developed extending the capability of CAAT-S to resolve the large number of high frequency modes, and making it suitable for turbofan engine noise prediction. CAAT-S calculated sound power level (PWL) underpredicts data by about 3 dB for both LVC and LN configurations. However, CAAT-S trend predictions are within the scatter of the experimental data. These results validate CAAT-S for moderate to high subsonic Mach numbers and over a broad range of blade passing frequencies.
Geometrically Non-linear Analysis of Functionally Graded Material (FGM) Plates and Shells using a Four-node Quasi-Conforming Shell Element

The four-node quasi-conforming shell element was extended in the present article to the case of geometrically non-linear behavior of the FGM plates and shells. The high stress occurring in the FGM structures will affect its integrity and the structures is susceptible to failure. Therefore, we focus on the effect of volume fraction of the constituent materials in the mechanical behavior of FGM plates and shells. The material properties are assumed to be varied in the thickness direction according to a sigmoid function in terms of the volume fraction of the constituents. The series solutions of sigmoid FGM (S-FGM) plates, based on the first-order shear deformation theory and Fourier series expansion are provided as the reference solution for the numerical results. In quasi-conforming formulation, the tangent stiffness matrix is explicitly integrated. This makes the element computationally efficient in the non-linear analysis. Several selected examples of non-linear analysis of FGM shells are included in the article for the illustration of possibilities of the presented formulation. It is seen that the present results for the non-linear behavior of FGM plates and shells can provide a useful benchmark to check the accuracy of related numerical solutions.
Low aspect ratio micron size tunnel magnetoresistance sensors with permanent magnet biasing integrated in the top lead

Optimized single magnetic bead detection requires magnetic sensors with an improved field detection limit and a sensor area matching the bead cross section (micron size spatial resolution). This work shows that square micron sized tunnel magnetoresistance sensors can be fabricated with integrated longitudinal permanent magnet (PM) biasing that show a linearized field response and low noise. PMs (Co66Cr16Pt18) were integrated in the top lead of an AlOx based magnetic tunnel junction sensor for transfer curve linearization. Sensors patterned with dimensions down to 3 × 3 μm2 present field detection limits of 6 nT/Hz0.5 and 3 nT/Hz0.5 at 10 kHz and 500 kHz, respectively, corresponding to a field sensitivity of 1.8% per mT (linear field detection range ΔB = −8 mT + 8 mT) and αH = 3.9 ± 0.3 × 10−10 μm2 (RxA = 1.9 kΩ μm2).
Improved estimation of direction of arrival of sound sources for hearing aids using gyroscopic information

Determining the direction of arrival (DOA) of a sound source is important in spatial audio signal processing, as it can lead to substantial improvement in noise reduction performance. Techniques such as generalized cross correlation with phase transform (GCC-PHAT) and adaptive eigenvalue decomposition (AED) perform optimally when the measurement microphones are fixed in place. However, hearing-aid microphones move with the listener? s head movements, which can result in momentarily inaccurate directional estimates and noise artifacts in the output signal. Techniques such as GCC-PHAT experience degraded short-term performance in the presence of multiple signals and noise. The system presented measures instantaneous head movement velocity using a micro-electromechanical systems (MEMS) gyroscope attached to binaurally-communicating hearing aids. Estimates of DOA for physically stationary sources are shifted based on the gyroscope's head-movement information. Using GCC-PHAT with gyroscopic input can produce robust in situ DOA estimates for several sources in reverberant environments. In addition, the gyroscope allows an adaptive beamformer to be steered to a target direction, compensating for head movements on a very short timescale during DOA estimation. Results show improved localization performance over a standard GCC-PHAT system during head movements.
Influence of hot phonons on electronic noise in GaAs

We present a Monte Carlo investigation of the influence of the nonequilibrium phonon population on second‐order transport properties in GaAs. We calculate the velocity and energy autocorrelation functions and the velocity–energy cross‐correlation functions, both for the case with and without phonon perturbation. By comparing the results, we find significant modifications in the correlation functions and consequently in the equivalent noise temperature due to the presence of the nonequilibrium phonons.
Advances and Unsolved Issues in Pulsating Heat Pipes

Pulsating (or oscillating) heat pipes (PHP or OHP) are new two-phase heat transfer devices that rely on the oscillatory flow of liquid slug and vapor plug in a long miniature tube bent into many turns. The unique feature of PHPs, compared with conventional heat pipes, is that there is no wick structure to return the condensate to the heating section; thus, there is no countercurrent flow between the liquid and vapor. Significant experimental and theoretical efforts have been made related to PHPs in the last decade. While experimental studies have focused on either visualizing the flow pattern in PHPs or characterizing the heat transfer capability of PHPs, theoretical examinations attempt to analytically and numerically model the fluid dynamics and/or heat transfer associated with the oscillating two-phase flow. The existing experimental and theoretical research, including important features and parameters, is summarized in tabular form. Progresses in flow visualization, heat transfer characteristics, and theoretical modeling are thoroughly reviewed. Finally, unresolved issues on the mechanism of PHP operation, modeling, and application are discussed.
ASCA observations of cooling flows in clusters of galaxies

ASCA spectra of the central regions of three cooling flows, in the Perseus, Centaurus, and A1795 clusters, together with the spectrum of the center of the Coma Cluster, are studied. Absorbed, cooler and/or cooling components are required for the cooling flow spectra but not for that of the Coma Cluster. Problems have been encountered with the basic plasma emission models in the energy range of the iron L complex, which preclude further detailed analysis at present. Our results show the potential of ASCA data for revealing the structure of cooling flows.
Forecasting Capabilities for the London 2012 Olympics

The provision of weather forecasts for the London Olympic and Paralympic Games in 2012 offered the opportunity for the Met Office to accelerate the transition to operations of several advanced numerical modeling capabilities and to demonstrate their performance to external scientists. It was also an event that captured public interest, providing an opportunity to educate and build trust in the weather forecasting enterprise in the United Kingdom and beyond. The baseline NWP guidance for the duration of the Olympic Games came from three main configurations of the Met Office Unified Model: global 25-km deterministic, North Atlantic/Europe 18-km ensemble, and U.K. 1.5-km deterministic. The advanced capabilities demonstrated during the Olympic Games consisted of a rapid-update hourly cycle of a 1.5-km grid length configuration for the southern United Kingdom using four-dimensional variational data assimilation (4D-Var) and enhanced observations; a 2.2-km grid length U.K. ensemble; a 333-m grid length configur.
Improved calculations of leading-edge separation from slender, thin, delta wings

In previous calculations (Mangler & Smith 1959) of the vortex-sheet model of leading-edge separation, only qualitative agreement was found with experimental observations. Because the numerical treatment of the model was then necessarily incomplete, it was uncertain how far the lack of quantitative agreement was to be attributed to the limitations of the model. The use of an automatic digital computer has now made it possible to reduce the uncertainties in the calculation to a negligible level. The features of interest in the real flow are more accurately predicted and the remaining discrepancies can be ascribed to the deficiencies in the model. The paper describes the method used to locate the vortex sheet and determine its strength in terms of the two boundary conditions on it; assesses the credibility of the results; and relates them to the observations. It is concluded that the model successfully predicts the observed height of the vortex above the wing, though the predicted lateral position is in error by up to 6% of the semi-span of the wing. This error falls as the incidence increases and is less when transition occurs in the boundary-layer upstream of secondary separation. Normal force is predicted accurately as is the distribution of pressure on the lower surface and the inboard part of the upper surface. The observed suction peak below the vortex changes its character when transition occurs in the boundary-layer upstream of secondary separation. The model predicts the suction peak in the turbulent case fairly well, but it is clear that detailed prediction of the suction peak is not possible by a model which is wholly inviscid.
Multiple Regimes of Wind, Stratification, and Turbulence in the Stable Boundary Layer

AbstractA long time series of temporally high-resolution wind and potential temperature data from the 213-m tower at Cabauw in the Netherlands demonstrates the existence of two distinct regimes of the stably stratified nocturnal boundary layer at this location. Hidden Markov model (HMM) analysis is used to objectively characterize these regimes and classify individual observed states. The first regime is characterized by strongly stable stratification, large wind speed differences between 10 and 200 m, and relatively weak turbulence. The second is associated with near-neutral stratification, weaker wind speed differences between 10 and 200 m, and relatively strong turbulence. In this second regime, the state of the boundary layer is similar to that during the day. The occupation statistics of these regimes are shown to covary with the large-scale pressure gradient force and cloud cover such that the first regime predominates under clear skies with weak geostrophic wind speed and the second regime predomin.
Strong-field coherent backscattering of light in ultracold atomic 85Rb

We report experimental observations of polarization-dependent coherence loss occurring in strong-field multiple scattering of light in ultracold atomic 85Rb. A measure of coherence in multiple light scattering is the degree of contrast of the coherent backscattering enhancement from the vapour. For resonance saturation parameters up to 9, we see light-polarization-dependent modification of the backscattering enhancement, suggesting that inelastic atomic light scattering and dynamic atomic magnetization may play important roles in the multiple scattering process for 85Rb.
Statistical CT noise reduction with multi-scale decomposition and penalized weighted least square for incomplete projection data

Tremendous efforts have been devoted to decreasing x-ray radiation dose in diagnostic CT while maintaining the image quality. The statistical noise reduction with iterative algorithm in the projection domain has been one of the major research subjects in CT technologies. Previously, we have proposed a statistical noise reduction with multi-scale decomposition and penalized weighted least square (PWLS) in the projection domain, in which the Markov Random Field (MRF) penalty function is incorporated. In this work, by taking the variation or irregularity of sampling interval along each dimension of the projection domain, we extend our previous method to deal with the situations of incomplete projection data, covering sparse view sampling, latitudinal data truncation and photon starvation. Using the computersimulated projection data of a performance phantom and the FORBILD thorax phantom, we evaluate and verify the performance of the proposed method.
Confirmation of Dust in Damped Lyman-Alpha Systems

As part of a search for dust at high redshifts, we have acquired new spectra of quasars in the Wolfe et al. sample : 13 with damped Lyα systems along the lines of sight and 15 without. Our spectra cover the region 3950-6900 A at a resolution of 15 A with signal-to-noise of 10-50. We have determined spectral indices over a common range of wavelengths in the rest frames of the quasars between Lyα and C IV emission. Several internal and external checks indicate that the typical errors in the spectral indices are ±0.1.
On the eigenvalues of certain Hermitian operators

As for general kernels p(x), little has been proved but much has been suspected. Bellman and Latter [1] have obtained upper and lower bounds for the largest eigenvalue of (1.1) for quite general p, these bounds, however, being rather weak for most interesting kernels. More to the point is a conjecture of Kac, Murdock, and Szego [5]. Assume p(x) > 0 end f0(1 +x2)p(x)dx< c. Denote the positive eigenvalues of (1.1) by
Quantitative feedback-feedforward control for model matching and disturbance rejection

This study addresses two major single-input single-output control problems involving both feedback and feedforward actions: (i) the model matching in reference tracking and (ii) the rejection of measurable disturbances. Its aim is to overcome the limitations of inversion-based feedforward design methods when system uncertainty is considered, and to find a control engineering solution based on the quantitative feedback theory (QFT). The proposed methodology leads to minimum cost of feedback by limiting the feedback action to the strictly necessary amount that enables the use of a feedforward controller. Although the model matching problem had drawn some attention of the QFT community in the last few years, the measurable disturbance rejection problem remained unaddressed. This study provides a novel solution for both of them in which the need for feedback is linked to the existence of a common feedforward solution for all plants within the model uncertainty. This work also deals with the generation of the corresponding quadratic inequalities and new QFT bounds for the mentioned feedback demand. A practical and well-known benchmark example illustrates the main details and advantages of the new methodology.
Multiscale numerical method for nonlinear Maxwell equations

The aim of this work is to propose an efficient numerical approximation of high frequency pulses propagating in nonlinear dispersive optical media. We consider the nonlinear Maxwell's equations with instantaneous nonlinearity. We first derive a physically and asymptotically equivalent model that is semi-linear. Then, for a large class of semi-linear systems, we describe the solution in terms of profiles. These profiles are solution of a singular equation involving one more variable describing the phase of the solution. We introduce a discretization of this equation using finite differences in space and time and an appropriate Fourier basis (with few elements) for the phase. The main point is that accurate solution of the nonlinear Maxwell equation can be computed with a mesh size of order of the wave length. This approximation is asymptotic-preserving in the sense that a multi-scale expansion can be performed on the discrete solution and the result of this expansion is a discretization of the continuous limit. In order to improve the computational delay, computations are performed in a window moving at the group velocity of the pulse. The second harmonic generation is used as an example to illustrate the proposed methodology. However, the numerical method proposed for this benchmark study can be applied to many other cases of nonlinear optics with high frequency pulses.
Nonlinear stability of strong detonations for a viscous combustion model

Strong detonations for a viscous combustion model are studied. These waves are of ZND (Zeldovich–von Neumann–Doring) type. It is shown that these waves are nonlinearly stable. The analysis consists of an energy method for the fluid variable and a pointwise estimate for the reactant. Strong detonations are compressive, which allows for a priori determination of their time-asymptotic location by the conservation law for the perturbation.
Time-dependent, long-term hydrodynamic simulations of the inner protoplanetary disk. I. The importance of stellar magnetic torques

Aims. We conduct simulations of the inner regions of protoplanetary disks (PPDs) to investigate the e ﬀ ects of protostellar magnetic ﬁelds on their long-term evolution. We use an inner boundary model that incorporates the inﬂuence of a stellar magnetic ﬁeld. The position of the inner disk is dependent on the mass accretion rate as well as the magnetic ﬁeld strength. We use this model to study the response of a magnetically truncated inner disk to an episodic accretion event. Additionally, we vary the protostellar magnetic ﬁeld strength and investigate the consequences of the magnetic ﬁeld on the long-term behavior of PPDs. Methods. We use the fully implicit 1 + 1D TAPIR code which solves the axisymmetric hydrodynamic equations self-consistently. Our model allows us to investigate disk dynamics close to the star and to conduct long-term evolution simulations simultaneously. We assume a hydrostatic vertical conﬁguration described via an energy equation which accounts for the radiative transport in the vertical direction in the optically thick limit and the equation of state. Moreover, our model includes the radial radiation transport in the stationary di ﬀ usion limit and takes protostellar irradiation into account. Results. We include stellar magnetic torques, the inﬂuence of a pressure gradient, and a variable inner disk radius in the TAPIR code to describe the innermost disk region in a more self-consistent manner. We can show that this approach alters the disk dynamics considerably compared to a simpliﬁed di ﬀ usive evolution equation, especially during outbursts. During a single outburst, the angular velocity deviates signiﬁcantly from the Keplerian velocity because of the inﬂuence of stellar magnetic torques. The disk pressure gradient switches sign several times and the inner disk radius is pushed towards the star, approaching < 1 . 2 R (cid:63) . Additionally, by varying the stellar magnetic ﬁeld strength, we can demonstrate several previously unseen e ﬀ ects. The number, duration, and the accreted disk mass of an outburst as well as the disk mass at the end of the disk phase (after several million years) depend on the stellar ﬁeld strength. Furthermore, we can deﬁne a range of stellar magnetic ﬁeld strengths, in which outbursts are completely suppressed. The robustness of this result is conﬁrmed by varying di ﬀ erent disk parameters. Conclusions. The inﬂuences of a prescribed stellar magnetic ﬁeld, local pressure gradients, and a variable inner disk radius result in a more consistent description of the gas dynamics in the innermost regions of PPDs. Combining magnetic torques acting on the innermost disk regions with the long-term evolution of PPDs yields previously unseen results, whereby the whole disk structure is a ﬀ ected over its entire lifetime. Additionally, we want to emphasize that a combination of our 1 + 1D model with more sophisticated multi-dimensional codes could improve the understanding of PPDs even further.
V380 Cygni Once More: A Close Detached Binary with an Evolved B‐Type Component. I. Spectroscopic Orbits

New spectroscopic and photometric observations of V380 Cygni, a bright early B‐type binary with an eccentric orbit and an evolved primary, B1.5 II–III, make possible a thorough study of this important, if not unique, system. In this first of two papers, the spectroscopic material is discussed. Values of the masses and provisional values of the radii are given, as is a spectroscopic estimate of the light ratio. The second paper will analyze the photometric material, including apsidal motion. The determination, with some degree of reliability, of the fundamental properties of an evolved early B‐type star in the 10 solar mass range will enable its structure and evolutionary status to be compared with the predictions of models, including a sensitive test of convective‐core overshooting.