Miracle-dz/UniFAR-FTUs huggingface dataset:
Ionospheric irregularities: The role of the equatorial ionization anomaly

The availability of similar ionosondes at four locations in India covering the regions from the equator to the northern crest of the equatorial ionization anomaly (EIA) has provided a unique opportunity to study the role of the EIA and related processes in the occurrence of spread F. The study is conducted during equinoctial months of high solar activity period (Rz=145), when the probability of occurrence of spread F is maximum. This study also deals with vertical movement of the F layer due to both electric field and neutral winds and the occurrence of spread F. The present study shows that a well‐developed anomaly beyond the latitude of 18°N is one of the base‐level conditions for the generation of spread F. The total integrated vertical movement is the controlling factor for the onset of spread F and not the peak value of h′F alone. There seems to be no threshold value in the altitude of the F layer (h′F) for the occurrence of spread F at all stations. The direction and magnitude of meridional winds that are crucial in the generation of spread. F showed higher values of poleward wind on non‐spread‐F days, indicating that the irregularity growth is suppressed due to the poleward wind.
The coupling of the finite element method and boundary solution procedures

The finite element method is now recognized as a general approximation process which is applicable to a variety of engineering problems—structural mechanics being only one of these. Boundary solution procedures have been introduced as an independent alternative which at times is more economical and possesses certain merits. In this survey of the field we show how such procedures can be utilized in conventional FEM context.
Assessment of thermodynamic models for dense gas dynamics

The accuracy of thermodynamic models in the computation of nonclassical gasdynamic phenomena is discussed, to investigate their suitability in connection with the design of experimental apparatuses aimed at the observation of nonclassical wavefields. The Soave–Redlich–Kwong and the Peng–Robinson are preliminarily suggested as alternative thermodynamic models to the Martin–Hou usually considered in nonclassical gasdynamics of fluorinated substances. The validity of these models is assessed by comparisons to reference experimental data for fluorinated R13, R125, C318, FC-72, FC-75, and SF6 and to the Martin–Hou model itself. The three models are found to exhibit a comparable accuracy for reduced volumes ranging from 1.4 to 2.5 and near the critical isotherm, i.e., in the thermodynamic region where heavier fluorinated substances such as PP10 are expected to exhibit nonclassical gasdynamic phenomena. The Soave–Redlich–Kwong and the Peng–Robinson models are then used to supplement previous numerical results fo.
Theoretical calculations of mobility enhancement in strained silicon

The conductivity enhancement of $n$-doped Si due to strain has been calculated by solving the Boltzmann equation within the relaxation-time approximation. For $T=0$, we determined the Fermi surface from first principles, whereas for $Tg0$, we modeled the Fermi surface using the effective-mass approximation. We explain the saturation of the conductivity enhancement with increasing strain in terms of the topology of the Fermi surface. We find in accordance with experiment a decreasing enhancement with increasing doping concentration.
Stress-induced fragmentation of multiwall carbon nanotubes in a polymer matrix

We report the observation of single nanotube fragmentation, under tensile stresses, using nanotube-containing thin polymeric films. Similar fragmentation tests with single fibers instead of nanotubes are routinely performed to study the fiber-matrix stress transfer ability in fiber composite materials, and thus the efficiency and quality of composite interfaces. The multiwall nanotube-matrix stress transfer efficiency is estimated to be at least one order of magnitude larger than in conventional fiber-based composites.
New developments for detector controllers at NOAO

The Torrent detector control system is being developed at NOAO as a follow-on to the MONSOON systems that have been used successfully for instruments at several institutions. The poster will cover the evolution of MONSOON into Torrent and will cover: Motivations, What's gained/What's lost, Major Technological Differences, Goals, plans and first users.
Semiparametric Estimation in the Rasch Model and Related Exponential Response Models, Including a Simple Latent Class Model for Item Analysis

Abstract The Rasch model for item analysis is an important member of the class of exponential response models in which the number of nuisance parameters increases with the number of subjects, leading to the failure of the usual likelihood methodology. Both conditional-likelihood methods and mixture-model techniques have been used to circumvent these problems. In this article, we show that these seemingly unrelated analyses are in fact closely linked to each other, despite dramatic structural differences between the classes of models implied by each approach. We show that the finite-mixture model for J dichotomous items having T latent classes gives the same estimates of item parameters as conditional likelihood on a set whose probability approaches one if T ≥ (J + 1)/2. Unconditional maximum likelihood estimators for the finite-mixture model can be viewed as Keifer-Wolfowitz estimators for the random-effects version of the Rasch model. Latent-class versions of the model are especially attractive when T is.
Noncryogenic pellet injector for diagnostic purposes on the RFX reversed field pinch

An impurity pellet injector is being developed for the RFX reversed field pinch (RFP) with three aims: measurement of the pitch of the magnetic field lines, transport studies, and first wall conditioning. The injector uses pneumatically accelerated metal sabots to launch the pellets. In this way the same barrel can be used for pellets of different sizes, speeds and materials. With drive pressures of 1–10 bars, velocities of 50–400 m/s can be obtained, which, based on code simulations, are adequate for core ablation. The measurement of the internal magnetic field will be done by diagnosing the direction of elongation of the pellet plasmoid using a masked charge coupled device camera capable of acquiring 28 images 40 lines×1024 pixels each with a maximum sampling rate of 50 kHz.
Anomalously high lifetimes measured by quasi-steady-state photoconductance in advanced solar cell structures

Quasi-Steady-State Photoconductance is widely used in photovoltaics industry to measure the effective minority carrier lifetime of silicon wafers, a key material parameter affecting final solar cell efficiency. When interpreting photoconductance based lifetime measurements, it is important to account for various artefacts that can cause an over-estimation of the carrier lifetime, such as minority carrier trapping. This paper provides experimental evidence for another artefact in photoconductance lifetime measurements, affecting samples that have a conductive layer that is interrupted by lines of the opposite polarity doping, forming laterally alternating regions of p/n doping. This structure often appears in the emitter region of samples used to monitor the lifetime of interdigitated back contact cells. The cause of this artefact is linked to a reduction in the measured dark conductance. Experimental data are presented that suggest this is due to the formation of a phototransistor type structure on the sa.
Helioseismology data and the solar dynamo

Some of the difficulties raised by recent helioseismology data for dynamo wave models of the solar cycle are addressed. These data have been interpreted as indicating that the latitudinal variations of angular velocity across the convection zone are approximately independent of depth. Theoretical frequency splittings are calculated for several types of model of the Sun's internal rotation profile, and it is confirmed that models in which the rotation rate is constant on concentric cylinders are incompatible with the observed frequency-splitting data
Euler potentials for two current sheets along ambient uniform magnetic field

[1] Euler potentials of two current sheets of finite width parallel or antiparallel to each other and aligned with a uniform ambient magnetic field are constructed analytically. It is shown how analytic treatment can be simplified using complex number analysis. Our approach generalizes results obtained earlier for a system of two line currents (wires). In the present solution the latter system represents a limiting case, and differences between results from configurations with sheets/wires are discussed. The solution is applied for study of bouncing motion of particles trapped between mirror points of this field structure. The result can be applied to Birkeland currents and to laboratory plasma experiments.
High-speed and high-dynamic range difference imaging based on the near-sensor image processing concept

The paper describes the Near Sensor Image Processing (NSIP) paradigm developed in the early 1990s and shows that it was a precursor to recent architectures proposed for direct (in the sensor) image processing and high dynamic range (HDR) image sensing. Both of these architectures are based on the specific properties of CMOS light sensors, in particular the ability to continuously monitor the accumulation of photon-induced charge as a function of time. We further propose an extension of the original NSIP pixel to include a circuit that facilitates temporal and spatio-temporal processing.
Microplastics in fish gut, first records

This preliminary study investigated the abundance of microplastic particles in gastrointestinal tracts of the dace (Leuciscus leuciscus L.) from the Tom River, a large tributary of the Ob River in West Siberia. A total of 13 dace specimens of 2+ to 4+ years of age were studied. Microplastic particles extracted from fish guts were counted and classified by shapes and sizes. In average 204 ± 28.7 items of microplastics were detected for one dace specimen. Microplastic particles were categorized as fragments of irregular shape (70%), spheres (16%), films (7%) and fibers (7%), with size ranging from <0.15 to 2.00 mm. The vast majority of detected microplastic particles (almost 80%) were less than 0.15 mm by their largest dimension. These data provide the first evidence of microplastics in fish from the Ob River system.
Suppression of carrier-induced ferromagnetism by composition and spin fluctuations in diluted magnetic semiconductors

We suggest an approach to account for spatial (composition) and thermal fluctuations in ``disordered'' magnetic models with given spatial dependences of the magnetic spin-spin interaction. Our approach is based on the introduction of a fluctuating molecular field (rather than mean field) acting between the spins. The distribution function of the above field is derived self-consistently. Our approach permits one to derive the equation for a critical temperature ${T}_{c}$ of a ferromagnetic phase transition with respect to the above fluctuations. On the base of the latter equation we analyze the influence of the fluctuations on ${T}_{c}$ in diluted magnetic semiconductors with RKKY spin-spin interaction. Our calculations predict the deviation of ${T}_{c}$ from its mean-field value ${T}_{c}^{\mathrm{MF}}$ by the factor $(1\ensuremath{-}\ensuremath{\nu}/{\ensuremath{\nu}}_{c}{)}^{\ensuremath{\lambda}},$ where $\ensuremath{\nu}{=n}_{e}{/n}_{i}$ is a ratio of carriers ${(n}_{e})$ and magnetic ion ${(n}_{i})$ concentrations; ${\ensuremath{\nu}}_{c}$ is a critical ratio such that at $\ensuremath{\nu}g{\ensuremath{\nu}}_{c}$ any ferromagnetic ordering is impossible. In the case of Mn ions with spins $S=5/2,$ we find ${\ensuremath{\nu}}_{c}\ensuremath{\simeq}0.264$ and $\ensuremath{\lambda}\ensuremath{\simeq}0.45,$ that constitute an optimal ratio $\ensuremath{\nu}\ensuremath{\simeq}0.11$ to obtain maximal ${T}_{c}$ as a function of carrier concentration.
Life Cycle and Precipitation Formation in a Hybrid-Type Hailstorm Revealed by Polarimetric and Doppler Radar Measurements

Abstract Hailstorm processes are studied using multiparameter radar observations of thunderstorm evolution. The storm turned out to be of hybrid type, having both multicellular (oscillatory nature of hail production) and supercellular (quasi-steady state of basic dynamics) characteristics. Its reflectivity field showed a V-like pattern not yet described in the literature as a typical severe storm pattern. The flow was characterized by an updraft zone surrounding an embedded downdraft collocated with the main precipitation shaft. The precipitation mainly originated from graupel particles growing at the fringes of the main updraft zone, whereas an accumulation zone of big drops was not present. In the weaker parts of the updraft the falling graupel melted and reached the ground as rain, whereas in the main updraft region those raindrops could be recirculated and subsequently freeze or be captured by hailstones already present aloft. In this region of high liquid water content large hail could be grown; it f.
The impedance and energy efficiency of a coaxial magnetized plasma source used for spheromak formation and sustainment

Electrostatic (dc) helicity injection has previously been shown to successfully sustain the magnetic fields of spheromaks and tokamaks. The magnitude of the injected magnetic helicity balances (within experimental error) the flux lost by resistive decay of the toroidal equilibrium. Hence the problem of optimizing this current drive scheme involves maximizing the injected helicity (the voltage‐connecting‐flux product) while minimizing the current (which multiplied by the voltage represents the energy input and also possible damage to the electrodes). The impedance (voltage‐to‐current ratio) and energy efficiency of a dc helicity injection experiment are studied on the CTX spheromak [Phys. Fluids 29, 3415 (1986)]. Over several years changes were made in the physical geometry of the coaxial magnetized plasma source as well as changes in the external electrical circuit. The source could be operated over a wide range of external charging voltage (and hence current), applied axial flux, and source gas flow rate.
Accurate Stick Model Development for Static Analysis of Complex Aircraft Wing-Box Structures

Aircraft simplified beam finite element models, also known as stick models, are commonly used in aircraft design and multidisciplinary design optimization. Accurate prediction of bending and twisting deformations of the aircraft structure in flight highly depends on the accuracy of the stiffness characteristics in its model. The process of generating a stick model depends on extracting the stiffness properties of the main structure and applying it to a set of beam elements extending along the structure's elastic axis. The present paper proposes a new methodology for extracting accurate bending stiffness properties of an aircraft wing using its 3-D finite element model. The paper reviews the different methodologies commonly used in the industry to generate stick models and gives an insight about the different approximations involved in each methodology and the impact of those approximations on the accuracy of the stick model performance. To validate the proposed methodology, the stick model of the DLR-F6 aircraft wing-box structure is generated using the proposed methodology and also using the methods available in literature. Deformations experienced by the generated stick models are compared with those obtained from the 3-D finite element model of the DLR-F6 aircraft wing box under the same loading condition. The results show that the stick model generated using the proposed methodology is in good agreement with the 3-D finite element model confirming its accuracy.
Assessing the response of forest productivity to climate extremes in Switzerland using model–data fusion

The response of forest productivity to climate extremes strongly depends on ambient environmental and site conditions. To better understand these relationships at a regional scale, we used nearly 800 observation years from 271 permanent long‐term forest monitoring plots across Switzerland, obtained between 1980 and 2017. We assimilated these data into the 3‐PG forest ecosystem model using Bayesian inference, reducing the bias of model predictions from 14% to 5% for forest stem carbon stocks and from 45% to 9% for stem carbon stock changes. We then estimated the productivity of forests dominated by Picea abies and Fagus sylvatica for the period of 1960–2018, and tested for productivity shifts in response to climate along elevational gradient and in extreme years. Simulated net primary productivity (NPP) decreased with elevation (2.86 ± 0.006 Mg C ha−1 year−1 km−1 for P. abies and 0.93 ± 0.010 Mg C ha−1 year−1 km−1 for F. sylvatica). During warm–dry extremes, simulated NPP for both species increased at higher and decreased at lower elevations, with reductions in NPP of more than 25% for up to 21% of the potential species distribution range in Switzerland. Reduced plant water availability had a stronger effect on NPP than temperature during warm‐dry extremes. Importantly, cold–dry extremes had negative impacts on regional forest NPP comparable to warm–dry extremes. Overall, our calibrated model suggests that the response of forest productivity to climate extremes is more complex than simple shift toward higher elevation. Such robust estimates of NPP are key for increasing our understanding of forests ecosystems carbon dynamics under climate extremes.
Strong ferromagnetic Josephson devices with optimized magnetism

We show that by interfacing Co with Rh in Nb-based superconductor-ferromagnetic-superconductor (SFS) Josephson devices, the bulk magnetization of the Co barrier is completely preserved, thus eliminating the issue of a magnetic dead layer present in other SFS devices. Electrical measurements demonstrate high transparency for Cooper pairs at the Rh/Co interface which results in large critical currents in the π state which are comparable to those of Nb/Co/Nb devices [J. W. A. Robinson et al., Phys. Rev. Lett. 97, 177003 (2006)].
The Validation of ATSR Using Aircraft Radiometer Data over the Tropical Atlantic

Abstract The First ATSR Tropical Experiment was carded out in November 1991 over the tropical Atlantic to validate daytime measurements of sea surface temperature (SST) made by the Along Track Scanning Radiometer (ATSR) on the European remote sensing satellite, ERS-1. An airborne infrared radiometer with channels at 11 and 12 µm spectrally matched to those on the ATSR was used to make nadir, 60° to nadir, and zenith view radiance measurements at a number of different altitudes from 70 m to 8 km above the sea surface. The effect of stratospheric aerosols on the ATSR radiances, due to the June 1991 eruption of Mount Pinatubo, was quantified as nadir view brightness temperature deficits of up to 0.6 K at 11 µm. ATSR retrievals of SST (using both nadir and forward views) were compared with SSTs inferred from low-level radiance measurements of the sea surface that were unaffected by atmospheric absorption. ATSR SSTs retrieved using the nadir only views had negative (i.e., cold) biases of about 2 K. If the forw.
Urban Influence on a Strong Daytime Air Flow as Determined from Tetroon Flights

Abstract Tetroon flights across Oklahoma City indicate the influence of an isolated urban area on the horizontal and vertical air velocity at heights near 400 m in relatively strong (13 m sec−1) daytime flow. The Lagrangian measurements so obtained are collated with fixed-point measurements of horizontal and vertical velocity on a 460 m television tower. Above the city in the morning there is a mean trajectory turning toward lower pressure of 10°. This turning, presumably fractionally induced, is noted only weakly in the afternoon and not all in the evening, but there is slight evidence for a bending of the trajectories around the city at these later times. During the day the city appears as the source of a plume of ascending air motion extending at least 30 km downwind of the city, with both tetroon and tower measurements indicating a mean upward velocity of almost 0.4 m sec−1 ten kilometers downwind of city-center at heights near 400 m. On the average the magnitude of the stress determined from the cova.
EQUILIBRIUM, STABILITY AND DYNAMICAL RESPONSE IN A MODEL OF THE EXTRINSIC APOPTOSIS PATHWAY

In the past few years several mathematical models have been proposed to formally represent the biochemical processes that lead to the programmed death of the cell (apoptosis) starting from an intrinsic or extrinsic stimulus. In this paper we consider the model proposed by Eissing and colleagues in 2004 and, compared to the previously published results, provide several original contributions. We prove formally that the model can have one, two or three equilibrium states; one of these (the life equilibrium) represents the normal state of the cell: we state a stability criterion for this equilibrium and prove that its stability/instability is related to the number of equilibrium states. A large sample of models with randomly generated parameter vectors (representative of a population of cells) is numerically analyzed as regards both the equilibria and respective stability properties, and the dynamical behavior. Many patterns of stable/unstable equilibrium states, and different types of bifurcations are discovered. Correlations between model parameters, equilibrium patterns and equilibrium concentration of a critical protein are also carried out. The analysis of the dynamical time responses shows that the richness of behaviors accounted by the model is much larger than that implied by the classification into life-monostable, bistable, death-monostable models.
An eddy-viscosity subgrid-scale model for turbulent shear flow: Algebraic theory and applications

An eddy-viscosity model is proposed and applied in large-eddy simulation of turbulent shear flows with quite satisfactory results. The model is essentially not more complicated than the Smagorinsky model, but is constructed in such a way that its dissipation is relatively small in transitional and near-wall regions. The model is expressed in first-order derivatives, does not involve explicit filtering, averaging, or clipping procedures, and is rotationally invariant for isotropic filter widths. Because of these highly desirable properties the model seems to be well suited for engineering applications. In order to provide a foundation of the model, an algebraic framework for general three-dimensional flows is introduced. Within this framework several types of flows are proven to have zero energy transfer to subgrid scales. The eddy viscosity is zero in the same cases; the theoretical subgrid dissipation and the eddy viscosity have the same algebraic structure. In addition, the model is based on a fundament.