Miracle-dz/UniFAR-FTUs huggingface dataset:
Modeling the Response from a Cascade to an Upstream Acoustic Disturbance

Time-accurate Euler flow field simulations for the flow through a two-dimensional cascade subjected to an upstream acoustic disturbance were used as the basis for a small disturbance model to predict the reflected response upstream of the cascade. The small disturbance model results in a linear system of algebraic equations for the properties of the reflected and transmitted disturbances. The model predicts the reflected and transmitted responses as a function of the cascade blade geometry, the disturbance strength, and the initial flow properties prior to the upstream disturbance. The predicted results from the small disturbance model were then compared with the Euler analysis results for a two-dimensional cascade. Agreement between the model and the Euler data indicated that the model was potentially useful as a basis for an outflow boundary condition for time-accurate Euler/Navier-Stokes (ENS) simulations of supersonic mixed compression inlet flows needed to determine the stability margin of an inlet that encounters an atmospheric disturbance. This boundary condition must provide an approximation of the response from the compressor by the inlet flow at the face of the compressor when a disturbance from upstream passes through the inlet and into the compressor. A new characteristic boundary condition based on the small disturbance response model was formulated and demonstrated independently in two one-dimensional Euler codes. The one-dimensional Euler codes with the new boundary condition and with existing boundary condition formulations were used to predict the reflection response for an axial compressor experiment. The new boundary condition was found to provide a significant improvement in accuracy for the reflection response of an acoustic disturbance from a compressor relative to existing outflow boundary condition models. For a supersonic mixed compression inlet, a one-dimensional Euler code was also used to demonstrate the dependence of the inlet normal-shock response and unstart tolerance on the outflow boundary condition.
Optoelectronic transient characterization of ultrafast devices

Recent advances in state-of-the-art optoelectronic techniques applied to areas pertinent to transistor small-signal and large-signal characterization are discussed. The aspects of optoelectronic techniques for electrical signal measurement, generation, and transmission are studied. On the basis of these results, a large-signal digital-switching transistor characterization methodology is developed. This methodology is used to estimate the parameters of a high-electron-mobility transistor and to obtain the large-signal characteristics of this device on a picosecond time scale. The measurements are compared to a SPICE-based time-domain model. The time-domain measurement technique is extended to obtain two-port frequency-domain characteristics of another, similar transistor with a 100-GHz bandwidth. These results compare favorably to conventional HP8510 network analyzer measurements over a common frequency span of 40 GHz. >
I. The solar and lunar diurnal variations of terrestrial magnetism

The regular daily changes of the earth’s magnetism, considered as a world-wide phenomenon, afford a problem of much interest and importance. It is one, moreover, which the researches of Balfour Stewart and Schuster have shown to be more vulnerable to attack than seem most of the problems of terrestrial magnetism. But in spite of their success, and of the contributions of subsequent writers, the comprehensive study of the subject has suffered undeserved neglect. It seems an unfortunate fact that the efforts of magneticians are unduly devoted to the accumulation of data, the time and labour spent in their discussion being, proportionately, inconsiderable. The promising theory that the daily magnetic variations arise mainly from electric currents circulating in the upper atmosphere, under the impulsion of electromotive forces produced by the convective motion of the air across the earth’s permanent magnetic field, was first propounded by Balfour Stewart. In a simple but penetrating discussion of the features both of the solar and lunar diurnal variations, he showed the power of this theory to account for the facts in a way which none of the other theories then current could do.
A two-phase method based on OBDD for searching for splitting strategies of large-scale power systems

System splitting problem, also known as controlled system separation problem, is to determine proper splitting points to split the entire interconnected transmission network into islands of load with matched generation when islanding operation of system is unavoidable. It is very difficult because of combinatorial explosion of searching space with the size of power network increasing. This paper proposes a two-phase method to find proper splitting strategies in real time by introducing the graph-model of system splitting problem. The method can narrow down the strategy space by highly efficient OBDD-based algorithm in the first phase and give all proper splitting strategies by power-flow calculation in the second phase. Simulation results on IEEE 30-bus test network shows that this method can quickly (in several seconds) give all proper splitting strategies guaranteeing synchronization, power balance and satisfaction to capacity constraints of transmission lines and other facilities in each island.
A Parameter Sweep Experiment on the Effects of the Equatorial QBO on Stratospheric Sudden Warming Events

The effects of the equatorial quasi-biennial oscillation (QBO) on stratospheric sudden warming (SSW) events are investigated by performing long time integrations with a simple global circulation model under a perpetual winter condition. Zonal momentum forcing is imposed to produce a westerly or easterly phase of the QBO in the equatorial stratosphere, and a parameter that determines strength and direction of the forcing is swept for nine values as an experimental parameter. The polar night jet is weaker and polar stratosphere is warmer in the runs with easterly ‘‘QBO wind’’ forcing, in qualitative agreement with the observational result. The polar night jet is strongest for a moderate westerly forcing, while it becomes weaker for too strong westerly forcing. Occurrence of SSW events is irregular, intermittent, and least frequent in the run with the moderate westerly forcing. As a result, frequency distribution of the polar stratospheric temperature shows the largest skewness. The frequency distribution of polar temperature is systematically dependent on the QBO wind forcing not only in the stratosphere but in the troposphere. The dependence is statistically significant even in the troposphere in spite of heavy overlap of the frequency distributions. Composite analysis for a large number of SSW events shows downward influence of the upper-stratospheric warming to the lower levels in two characteristic timescales. Short-time cooling response within several days is extended to the summer hemisphere, while long-time response persisting a couple of weeks is confined within the winter hemisphere and extends down to the level near the tropopause. The response of polar temperature in the lower stratosphere shows systematic dependence on the QBO wind forcing; mean warming rate is smallest for the moderate westerly forcing, and warming is more rapid for the easterly forcings.
An update on non-stationary oblique shock-wave reflections: actual isopycnics and numerical experiments

Nonstationary oblique shock-wave reflections over compressive wedges in air and argon were investigated using infinite-fringe interferometric techniques. These allowed direct, continuous and accurate observations of the isopycnics (lines of constant density) of the flow field. The initial pressures for these experiments were made as high as possible (15 to 250 torr) in order to increase the number of isopycnics and to enhance their details and distribution along the wedge surface over a shock-Mach-number range 2.0 < Ms [les ] 8.7. Included in the study were two cases of regular reflection (RR) and one of each single Mach reflection (SMR), complex Mach reflection (CMR) and double-Mach reflection (DMR) for air, and one RR, SMR, CMR and DMR for argon. These particular cases, which we investigated previously in N2 and Ar using a finite-fringe technique, have been used by computational fluid dynamicists to check their finite-difference results against our experimental data. It will be shown that the isopycnic structure previously reported by us differs in detail, in most cases, from that of the present study. The major difference arises from the fact that it was only possible previously to obtain discrete points on isopycnics and along the wedge surface. Consequently, the results obtained before were not as accurate. Comparisons were made of actual wall-density distributions with numerical simulations of the density contours of the various flows obtained by a number of authors. Each numerical method displays its advantages and disadvantages in describing the details of the flow fields. The present experimental results for air are new. They are of great interest from a practical viewpoint. The experiments in argon were redone to provide better data for a gas free from real-gas effects in the range of initial conditions considered, in order to simplify the computations in the numerical simulations. Although the recent numerical simulations are better than those reported previously, additional efforts are required to improve the predictions of the shape, location and values of the isopycnics and other flow isolines in the various regions and along the wall, and to render the predictions free of computer ‘noise’. It is worth noting that real-gas effects did not play any significant role in determining the various wave systems in RR, SMR, CMR and DMR; a different claim was made in our previous work. Relaxation of nitrogen in air can be seen however, at the highest shock Mach numbers (Ms = 7.19 and 8.70), with relaxation lengths in good agreement with accepted predictions.
On Testing the Validity of Sequential Probability Forecasts

Events are observed sequentially, and at each stage a probability for the next event is assessed. We consider the relationship between the sequence of probability forecasts and the sequence of outcomes. We argue that the forecasts may be considered “empirically valid” when both these sequences are consistent with a common joint distribution for the events. To aid in assessing validity, we introduce various test statistics that measure, in a natural way, the empirical performance of the probability forecasts in the light of the outcomes obtained. It is shown that under the null hypothesis of forecast validity, such statistics will, after suitable normalization, have a Standard normal (or chi-squared) distribution, virtually irrespective of the common joint distribution supposed to underlie both sequences.
The natural frequency of oscillation of gas bubbles in tubes

A numerical study is presented of the natural frequency of the volume oscillations of gas bubbles in a liquid contained in a finite-length tube, when the bubble is not small with respect to the tube diameter. Tubes rigidly terminated at one end, or open at both ends, are considered. The open ends may be open to the atmosphere or in contact with a large mass of liquid. The numerical results are compared with a simple approximation in which the bubble consists of a cylindrical mass of gas filling up the cross section of the tube. It is found that this approximation is very good except when the bubble radius is much smaller than that of the tube. An alternative approximate solution is developed for this case. The viscous energy dissipation in the tube is also estimated and found generally small compared with the thermal damping of the bubble. This work is motivated by the possibility of using gas bubbles as actuators in fluid-handling microdevices.
The effect of thin scattering layers on the determination of wind by Doppler radars

It has recently been suggested that the observed tendency for intense turbulence to occur in thin layers in the atmosphere introduces an error in horizontal wind measurements with MST radars, even in the absence of wind shear. This effect, called the finite range volume effect, is a consequence of the tilted pulse volume when using the Doppler technique. A model is shown which illustrates that this effect may be very important in MST radar measurements when wide antenna beam widths are used. These model results are supported by observations performed with the MU radar in Japan, where wind measurements with different beam widths have been performed. The impact of these measurements on MST radar design and possible methods to minimize the error are discussed.
Plasticity analysis of pure aluminium extruded with an RBD palm olein lubricant

In this study, a cold-work plane strain extrusion apparatus was used to perform plasticity analysis of a work piece that was extruded using RBD palm olein as a cold metal forming lubricant. The experimental apparatus consists of a set of two taper dies with 45-degree die half angles and a billet (work piece). The experiments were carried out at room temperature, which was within the range of 28 to 32°C. The testing lubricant was refined, bleached and deodorized palm olein (RBD palm olein). The billet material was annealed pure aluminium, Al 100. The experimental results focused on the extrusion force, surface roughness of both the deformation area and the product surface and sliding velocity. The grid lines, which were scribed on the billet, were used to observe and analyze the plastic flow in the material. The velocity distributions on the experimental surface of the billet were calculated using a visioplasticity method. Similar experimental and analytical investigations were carried out using additive-free paraffinic mineral oil and were compared to the investigation with RBD palm olein. The RBD palm olein showed a reduced extrusion force and a better quality surface roughness. The work piece that was extruded with RBD palm olein showed better plastic behavior as compared to those that were extruded with paraffinic mineral oil. It was confirmed that RBD palm olein shows satisfactory lubrication performance as compared to additive-free paraffinic mineral oil.
IDO1 Activity Predicts Lung Toxicity in Patients with Unresectable Stage III NSCLC and Chemoradiotherapy

Objectives Indoleamine 2,3-dioxygenase 1 (IDO1) acts as the key rate-limiting enzyme that converts tryptophan (Trp) to kynurenine (Kyn). Its activity was primarily induced by interferon-γ (IFN-γ), which was reported to play a role in the development of acute radiation-induced pneumonitis. In this study, we aimed to investigate the correlation between IDO1 activity and radiation-induced lung toxicity (RILT) in stage III nonsmall cell lung cancer (NSCLC) patients who were treated with chemoradiotherapy (CRT). Materials and Methods Systemic IDO1 activity was reflected by Kyn : Trp ratio. Plasma levels of Kyn and Trp in 113 stage III NSCLC patients were measured by high-performance liquid chromatography (HPLC) before the initiation of radiotherapy. Dynamic change of IDO1 activity was followed in 23 patients before, during, and after radiotherapy. We also used RNA sequencing (RNA-seq) data from the Cancer Genome Atlas Program (TCGA) database and performed gene set enrichment analysis (GSEA) to explore how IDO1 was involved in the development of RILT. Results 9.7% (11/113) of the whole group developed G3+ (greater than or equal to Grade 3) RILT. Preradiation IDO1 activity was significantly higher in patients who developed G3 + RILT than in nonG3 + RILT patients. (P = 0.029, AUC = 0.70). Univariate and multivariate analyses showed that high IDO1 activity was independently associated with the risk of G3 + RILT (P = 0.034). A predictive model combining both IDO1 activity and FEV1 was established for severe RILT and displayed a moderate predictive value (AUC = 0.83, P < 0.001). The incidence of G3 + RILT was 2.6% (1/38) in patients with an IDO activity ≤0.069 and FEV1 > 59.4%, and 50.0% (6/12) in those with an IDO activity >0.069 and FEV1 ≤ 59.4%. Of 23 patients with dynamic tracking, the IDO1 activity of postradiation was significantly lower than midradiation (P = 0.021), though no significant differences among the three time points were observed (P = 0.070). Bioinformatic analysis using RNA-seq data from 1014 NSCLC patients revealed that IDO mainly functioned in the inflammatory response instead of the late fibrosis process in NSCLC patients. Conclusion High baseline IDO1 activity combined with unfavorable baseline FEV1 was predictive of severe RILT in unresectable stage III NSCLC patients. IDO1 might play a role in the acute inflammatory response. Finding effective interventions to alleviate RILT using IDO inhibitors is warranted in the future.
All-Sky Catalogs of Superclusters of Abell-ACO Clusters

We present the results of a statistical analysis of structures in the Abell and ACO catalogs of clusters of galaxies. For both catalogs we have improved upon distance estimates for clusters without measured radial velocity and we discuss in detail the calibration of the magnitude-redshift relation. Through a percolation analysis we have obtained catalogs of superclusters at various density excesses: we analyze their reality and global properties, focusing in particular on the problem of the possible existence of large peculiar motions of clusters in superclusters
Electron mobility in dilute GaAs bismide and nitride alloys measured by time-resolved terahertz spectroscopy

We report time-resolved terahertz spectroscopy measurements of the electronic transport properties of dilute GaAs bismide and nitride alloys. The electron mobility for GaAs1−yBiy (y=0.84%) extracted from Drude fits to the transient complex conductivity was ∼2800cm2∕Vs at a carrier density of 2.7×1018cm−3, close to the mobility of 3300cm2∕Vs measured for GaAs at a similar carrier density. The electron mobility did not decrease significantly for Bi concentrations up to 1.4%. In contrast, the GaNxAs1−x (x=0.84%) and GaNxAs1−x−yBiy (x=0.85%, y=1.4%) films exhibited non-Drude behavior with a highly reduced electron mobility and suppressed conductivity at low frequencies indicative of carrier localization.
Secondary boundary layer and wall shear for fully developed flow in curved pipes

The secondary motion of incompressible fluid for a fully developed turbulent flow in horizontally laid curved pipes is theoretically analysed with the aid of the turbulent boundary–layer approach, integrating the Navier–Stokes equations and satisfying the continuity equation, having mean–time–average parameters. Outside the boundary layer that is developed due to the secondary flow, the inviscid motion of fluid is treated using the Euler and continuity equations. Inside the thin boundary layer, the Pohlhausen method is applied considering a one–seventh power distribution of velocity for solving the integrals of the Navier–Stokes equations. The expression of shear given by Blasius for the turbulent flow in pipes is incorporated into the integrals of the Navier–Stokes equations as an apparent shear to derive an implicit equation that is numerically solved to determine the boundary–layer thickness and subsequently the wall shear stress. The computational results of the boundary–layer thickness and the wall shear stresses are presented in non–dimensional (graphical) form for different Reynolds numbers and curvature ratios. The model is applicable over a wide range of Dean numbers (D) 57 ≤ D ≤ × 105.
Onward migration and onward precarity of Latin American labour migrants in postcrisis contexts in Europe

ABSTRACT The main aim of this paper is to shed light on the link between ‘onward migration’ and ‘onward precarity’ as an experience of continuous precariousness by paying attention to crisis/post-crisis contexts and how these contexts have led to precarity becoming structurally embedded in migrant labour markets in Europe. Onward migration studies have centrally focused on crisis contexts, but very little attention has been paid to post-crisis contexts. Thus, this article contributes to complementing the previous research on onward migration and onward precarity. The paper follows a qualitative and multi-sited approach based on in-depth interviews and discussion groups with Latin American migrants living in Madrid, Lisbon, and London. Our empirical analysis elucidates that labour mobility and onward migration are embedded in intersectional dynamics of exclusion which entail a continuous experience of multifaceted precarity.
Measurements of ion micro-beams in RPI-type discharges and fusion protons in PF-1000 experiments

The paper reports on experimental investigation of micro-beams of fast ions emitted from high-current pulse discharges within the RPI-IBIS (Rod Plasma Injector) device in Swierk and the PF-1000 (Plasma-Focus) facility in Warsaw. Time-integrated ion measurements were performed with pinhole cameras equipped with solid-state nuclear track detectors (SSNTDs). Before expositions the SSNTDs were calibrated by means of mono-energetic ion beams and/or Thomson-type parabolas recorded on the detector samples. The ion-pinhole cameras were placed at different angles to the symmetry axes of the investigated facilities. In order to record fast (>3 MeV) protons, which originated from D–D nuclear fusion reactions in the PF-1000 facility, the SSNTDs were covered with appropriate Al filters. Time-integrated measurements of the fusion protons were performed for chosen series of PF discharges. The paper presents for the first time detailed maps of the fast proton fluxes, which makes it possible to draw conclusions regarding the spatial distribution of the fusion-proton sources.
Tropical‐cyclone intensification and predictability in three dimensions

We present numerical‐model experiments to investigate the dynamics of tropical‐cyclone amplification and its predictability in three dimensions. For the prototype amplification problem beginning with a weak‐tropical‐storm‐strength vortex, the emergent flow becomes highly asymmetric and dominated by deep convective vortex structures, even though the problem as posed is essentially axisymmetric. The asymmetries that develop are highly sensitive to the boundary‐layer moisture distribution. When a small random moisture perturbation is added in the boundary layer at the initial time, the pattern of evolution of the flow asymmetries is changed dramatically, and a non‐negligible spread in the local and azimuthally‐averaged intensity results. We conclude, first, that the flow on the convective scales exhibits a degree of randomness, and only those asymmetric features that survive in an ensemble average of many realizations can be regarded as robust; and secondly, that there is an intrinsic uncertainty in the prediction of maximum intensity using either maximum‐wind or minimum‐surface‐pressure metrics. There are clear implications for the possibility of deterministic forecasts of the mesoscale structure of tropical cyclones, which may have a major impact on the intensity and on rapid intensity changes.