Miracle-dz/UniFAR-FTUs huggingface dataset:
On the unsteady squeezing of a viscous fluid from a tube

Abstract Viscous fluid is squeezed out from a shrinking (or expanding) tube whose radius varies with time as (1 – βt)½. The full Navier–Stokes equations reduce to a non-linear ordinary differential equation governed by a non-dimensional parameter S representing the relative importance of unsteadiness to viscosity. This paper studies the analytic solutions for large | S | through the method of matched asymptotic expansions. A simple numerical scheme for integration is presented. It is found that boundary layers exist near the walls for large | S |. In addition, flow reversals and oscillations of the velocity profile occur for large negative S (fast expansion of the tube).
Numerical Procedures for Surface Fitting of Scattered Data by Radial Functions

In many applications one encounters the problem of approximating surfaces from data given on a set of scattered points in a two-dimensional domain. The global interpolation methods with Duchon's “thin plate splines” and Hardy's multiquadrics are considered to be of high quality; however, their application is limited, due to computational difficulties, to $ \sim 150$ data points. In this work we develop some efficient iterative schemes for computing global approximation surfaces interpolating a given smooth data. The suggested iterative procedures can, in principle, handle any number of data points, according to computer capacity. These procedures are extensions of a previous work by Dyn and Levin on iterative methods for computing thin-plate spline interpolants for data given on a square grid. Here the procedures are improved significantly and generalized to the case of data given in a general configuration.The major theme of this work is the development of an iterative scheme for the construction of a smooth surface, presented by global basis functions, which approximates only the smooth components of a set of scattered noisy data. The novelty in the suggested method is in the construction of an iterative procedure for low-pass filtering based on detailed spectral properties of a preconditioned matrix. The general concepts of this approach can also be used in designing iterative computation procedures for many other problems.The interpolation and smoothing procedures are tested, and the theoretical results are verified, by many numerical experiments.
Accurate determination of saturation parameters for Cr 4+ -doped solid-state saturable absorbers

We describe a systematic, rigorous procedure for the determination of the optical absorption saturation parameters for Cr4+:YAG and Cr4+:forsterite crystals at 1064 nm. A rate-equation approach was used to analyze the cw and pulsed transmission data of several crystals by accounting for the transverse as well as longitudinal variation of the beam intensity, saturation effects, and excited-state absorption. Use of an iterative procedure whereby the cw and pulsed data were simultaneously analyzed led to a considerable reduction in the error for the determination of cross sections. The average value of the absorption cross section sigmaa and the normalized excited-state absorption cross section fp=sigmaesa/sigmaa were determined to be 6.13×10−19 cm2 and 0.45, respectively, for Cr4+:forsterite and 19.6×10−19 cm2 and 0.06, respectively, for Cr4+:YAG. Detailed comparison was also made with previous saturation measurements in the literature. Our results further show that lumped models based on the thin-length approximation should be used with caution in the determination of cross sections, especially when the pump beam is tightly focused inside the absorber.
Defect structure in selectively grown GaN films with low threading dislocation density

We have characterized by transmission electron microscopy (TEM) defect structures in GaN films grown selectively in hydride vapor-phase epitaxy (HVPE). In this experiment, growth was achieved on SiO2-stripe-patterned GaN layers that had been grown by metalorganic vapor-phase epitaxy (MOVPE) on sapphire substrates. Cross-sectional TEM revealed unambiguously that most of the dislocations, which originated from threading dislocations vertically aligned in the MOVPE-grown layer, propagated laterally around the SiO2 mask in the HVPE-grown film before the film thickness amounted to about 5 μm. This change of the propagation direction prevented the dislocations from crossing the film to the surface region and thus principally led to a drastic reduction in the threading dislocation density in thicker films.
High energy astrophysics with ground-based gamma ray detectors

Recent advances in ground-based gamma ray astronomy have led to the discovery of more than 70 sources of very high energy (Eγ ⩾ 100 GeV) gamma rays, falling into a number of source populations including pulsar wind nebulae, shell type supernova remnants, Wolf-Rayet stars, giant molecular clouds, binary systems, the Galactic Center, active galactic nuclei and ‘dark’ (yet unidentified) galactic objects. We summarize the history of TeV gamma ray astronomy up to the current status of the field including a description of experimental techniques and highlight recent astrophysical results. We also discuss the potential of ground-based gamma ray astronomy for future discoveries and describe possible directions for future instrumental developments.
Protostellar formation in rotating interstellar clouds. V - Nonisothermal collapse and fragmentation

Numerical calculations are presented for rigorous models spanning a four-dimensional parameter space of initial conditions of the three-dimensional collapse of rotating protostellar clouds, encompassing radiative transfer in the Eddington approximation and detailed thermodynamical relations. It is found that protostellar formation may involve a few stages of hierarchical fragmentation terminated by increased thermal pressure in the nonisothermal regime, that high thermal energy clouds remain nearly axisymmetric during the first dynamic collapse phase, and that very slowly rotating clouds can fragment. The presolar nebula was probably formed from a cloud with very little initial rotation. 37 references.
Multi‐year simulations using a regional‐climate model over the Iberian Peninsula: Current climate and doubled CO2 scenario

In order to analyse the regional climate sensitivity in the Iberian Peninsula and surrounding areas to the global change related to an increase of CO2, two simulations (current climate and scenario) are performed using a regional‐climate model (RCM) one‐way nested in a global circulation model (GCM). Both simulations cover a ten‐year period. The results of the control simulation (current climate) are compared to a climatological database. RCM and GCM representations of the climate are realistic, but the RCM shows more detailed results. Following this, a statistical analysis of the differences between current climate and double CO2 scenario simulations is carried out considering both 2 m temperature and precipitation. The analysis shows a significant warming in seasonal averages and important differences in the 2 m temperature interannual variability. Especially important is the strong increase in interannual variability of precipitation found in winter and autumn. Relationships between anomalies of general circulation (500 hPa geopotential field) and surface temperature, precipitation and cloudiness are also analysed, showing an important effect of cloud cover anomalies over the 2 m temperature interannual variability.
Formation and direct writing of color centers in LiF using a laser-induced extreme ultraviolet plasma in combination with a Schwarzschild objective

In order to generate high-energy densities of 13.5nm radiation, an extreme ultraviolet (EUV) Schwarzschild mirror objective with a numerical aperture of 0.44 and a demagnification of 10 was developed and adapted to a compact laser-based EUV source. The annular spherical mirror substrates were coated with Mo∕Si multilayer systems. With a single mirror reflectance of more than 65% the total transmittance of the Schwarzschild objective exceeds 40% at 13.5nm. From the properties of the EUV source (pulse energy 3mJ at 13.5nm and plasma diameter approximately 300μm), energy densities of 73mJ∕cm2 at a pulse length of 6ns can be estimated in the image plane of the objective. As a first application, the formation of color centers in lithium fluoride crystals by EUV radiation was investigated. F2, F3, and F3+ color centers could be identified by absorption spectroscopy. The formation dynamics was studied as a function of the EUV dose. By imaging of a pinhole positioned behind the plasma, an EUV spot of 5μm diameter.
Interaction Potential and Transport Coefficients for Li+ Ions in Helium

An extended group function model has been applied to determine the interatomic potential for the X state of HeLi+, to an accuracy superior to previously determined potentials. The potential has been used to calculate transport coefficients for Li+ ions in He at 77.5 and 295 K, and new precision measurements of the mobility as a function of E/N have been performed at these temperatures. The agreement between the theoretical and experimental mobility values is excellent, and well within the experimental scatter.
Yield and nutritional quality of soil‐cultivated crisphead lettuce (Lactuca sativa L. var. capitata) and corn salad (Valerianella spp.) harvested at different growing periods

Abstract Crisphead lettuce and corn salad varieties were grown during different growing seasons in the greenhouse or in the field under intensive tillage. They were evaluated for agronomic and nutritional quality to determine the influence of growing period, variety, and in the case of lettuce, leaf position (inner, middle, and outer leaf) on total and marketable yield, color parameters, relative chlorophyll, total sugars, isovaleric acid, total phenolic content (TPC), and multielement composition. Significant differences were found among total yield, color parameters (L*, b*, c*, and hue), and relative chlorophyll for crisphead lettuce, and color parameters (L*, a*, b*, c*, and hue) and relative chlorophyll for corn salad varieties. Relative chlorophyll was strongly correlated with most color parameters. The growing period affected yield, relative chlorophyll, TPC, total sugars, isovaleric acid, and multielement composition for corn salad, and the color parameter a* and relative chlorophyll for crisphead lettuce. The position of lettuce leaves had a significant effect on TPC, total sugars, and multielement composition. In addition, this study confirmed that farmers and consumers should pay attention to nutritional quality when selecting different lettuce and corn salad varieties.
Combining structured light and ladar for pose tracking in THz sensor management

Stand-off 3D THz imaging to detect concealed treats is currently under development. The technology can provide high resolution 3D range data of a passing subject showing layers of clothes and if there are concealed items. However, because it is a scanning sensor technology with a narrow field of view, the subjects pose and position need to be accurately tracked in real time to focus the system and map the imaged THz data to specific body parts. Structured light is a technique to obtain 3D range information. It is, for example, used in the Microsoft Kinect for pose tracking of game players in real time. We demonstrate how structured light can contribute to a THz sensor management system and track subjects in real time. The main advantage of structured light is its simplicity, the disadvantages are the sensitivity to lighting conditions and material properties as well as a relatively low accuracy. Time of flight laser scanning is a technique that complements structured light well, the accuracy is usually much higher and it is less sensitive to lighting conditions. We show that by combining the techniques it is possible to create a robust real time pose tracking system for THz sensor management. We present a concept system based on the Microsoft Kinect and a SICK LMS-511 laser scanner. The laser scanner is used for 2D tracking of the subjects, this tracking is then used to initialize and validate the Microsoft Kinect pose tracking. We have evaluated the sensors individually in both static and dynamic scenes and present their advantages and drawbacks.
Experiments at a two-scale dynamo test facility

A report of experimental results on dynamo action is presented, obtained at the Karlsruhe dynamo test facility. Former observations concerning the properties of the dynamo magnetic field are corroborated and complemented. The feedback of the dynamo magnetic field on the sodium velocity in the test module is analysed based on measurements employing permanent magnet potential sensors. The evaluation of time signals recorded by these probes shows that a growing dynamo magnetic field transforms hydrodynamic turbulent velocity profiles in channels into magnetohydrodynamic slug flow profiles, indicating a balance between pressure and Lorentz forces. Cross-correlations between time signals of the magnetic induction and the local velocity reveal a significant coherency between apparently random fluctuations of these relevant dynamo quantities.
Study of the interaction between the indentation size effect and Hall–Petch effect with spherical indenters on annealed polycrystalline copper

Methods to obtain tensile stress–strain properties of materials from a practically non-destructive indentation test are of great industrial interest. Nanoindentation is a good candidate. However, to do this successfully, indentation size effects must be accounted for. An indentation size effect with spherical indenters has been shown for a range of fcc metals with relatively large grain size (Spary et al 2006 Phil. Mag. 86 5581–93); the increase in yield stress being proportional to the inverse cube root of indenter radius. Here, we investigate these differences further and present results for the indentation size effect with spherical indenters on Cu samples with a range of different grain sizes from 1 µm to single crystal. The important experimental control parameter, of the relative size of the indentation compared with the grain size, is also explored by using indenters of different radii on the different grain sized samples. When the grain size, d, is less than 6 times the radius of the projected contact area, a, a Hall–Petch-like behaviour is observed superimposed on the indentation size effect. For d > 6a the indentation size effect dominates. The two effects may be combined by addition in quadrature. This new parametric function is able to predict the indentation pressure in annealed copper given input values of indenter radius and grain size.
Effects of pre-equilibrium nucleon emission on excitation functions of various reactions in vanadium induced by alpha particles

Excitation functions for the 51V(( alpha ,n), ( alpha ,3n), ( alpha ,p3n), ( alpha ,p6n), ( alpha , alpha 3n), ( alpha , alpha 2pn), ( alpha ,2 alpha ), ( alpha ,2 alpha n) and ( alpha ,2 alpha 3n)) reactions have been measured up to 120 MeV using the stacked foil technique with a view to improving the quality of data, which were measured with poor resolution scintillation and Ge(Li) detectors some 20 years ago. The reaction V( alpha ,p6n) is measured for the first time. The experimental results are compared with calculations considering equilibrium as well as pre-equilibrium reactions according to the hybrid model of Blann(1984). A broad general agreement is observed between the experimental results and theoretical predictions with an initial exciton configuration of n0=(4p0h).
Lagrange Spaces with -Metric

We study Lagrange spaces with -metric, where is a cubic metric and is a 1-form. We obtain fundamental metric tensor, its inverse, Euler-Lagrange equations, semispray coefficients, and canonical nonlinear connection for a Lagrange space endowed with a -metric. Several other properties of such space are also discussed.
A study of asymmetric reconnection scaling in the Lyon‐Fedder‐Mobarry code

Using a three‐dimensional magnetospheric simulation code we have studied the properties of magnetic reconnection at the subsolar point on solar wind parameters for southward interplanetary magnetic field conditions and compared the results with the predictions of the Cassak‐Shay theory. We find that this theory predicts reconnection rates on the order of our observations and produces reasonable predictions of the reconnection outflow speed. We have quantified the contributions that differences between the assumed and measured mass, energy, and outflow density scalings make to predictions of the reconnection rate and outflow speed. In general, the theory makes reasonable assumptions about the mass and energy flux into the reconnection layer, but their outflowing counterparts are overestimated due to the narrowness of the reconnection outflow jet. Lastly, we find that newly reconnected flux tubes exit the merging region before their mass density can equilibrate, requiring a correction to the predicted outflow density.
The coronal line spectrum of AS 295.

AS 295 was discovered originally as a twelfth magnitude star having H$alpha$ in emission. It has now been found that the twelfth magnitude star at that position is a normal K giant and that the emission spectrum actually originates in a much fainter star 3'' distant (here called AS 295 B), which in addition to bright lines of H, He i, He ii, and O i shows a number of the stronger coronal lines such as Fe x lambda6374 and Fe xiv lambda5303. The two stars have quite different radial velocities and are probably only aligned. Provided the Fe ions coexist, the coronal line region of AS 295 B must have a T/ sube/ of at least 1.25times10$sup 6$ K, the true value depending upon the amount of interstellar extinction, while the conventional emission spectrum probably arises in a cooler region having T/sube/approx. =20,000 K. Absolute fluxes measured for H$alpha$ and the coronal lines make possible a prediction of the X- ray (2--6 keV) and radio (2.7 GHz) fluxes of AS 295 B. The nondetection of AS 295 B at X-ray wavelengths is understandable. A very weak radio source has been discovered by Gregory and Seaquist at the optical positionmore » of AS 295 B, and at a flux density very close to that predicted for the optically thin case. Upon examination of the Maria Mitchell and Harvard plate collections, AS 295 B was found to have undergone a hitherto undetected nova-like outburst in 1965. However, the persistence of its coronal spectrum 10 years later is unprecedented among the novae that have shown coronal lines, although it may be related to the fact that AS 295 B is the slowest nova of the group. (AIP)« less
A New Method for Testing Interaction in Unreplicated Two-Way Analysis of Variance

For a two-way ANOVA table, with a single observation per cell, the standard approach is to assume that interaction between the two factors is negligible, and to base inferences about the main factors on the model without interaction. But there is no totally satisfactory method for testing if interaction can be ignored. The classical approach is to specify a functional form for the interaction terms, involving a small number of parameters, and then use an appropriate test. But, such tests have low power if the functional form is inappropriate. This has led researchers to propose tests which do not assume a specific form for the interactions. In this article, we present a new approach for testing interaction which also does not assume a specific form for the interaction. This approach is fairly simple and flexible, and its usefulness is illustrated with several examples. We also present a general result which shows that there is no test of interaction with good power properties against all types of interaction.
Family Household Characteristics and Stunting: An Update Scoping Review

Stunting remains a public health concern in developing countries. Factors related to stunting have been categorized using various frameworks. Family plays an important role in providing nutrients for children; however, no review specifies this aspect for identifying family characteristics related to stunting. This study aimed to identify family household characteristics related to stunting among children aged less than 5 years. A scoping review was undertaken with sources from PubMed, CINAHL, and Scopus, using the keywords “family characteristics” AND “growth”. Inclusion criteria were (1) correlational study; (2) published between 2018 and 31 July 2022; (3) families with children under the age of 5 years; and (4) independent variable any measure of stunting factors from family and household factors. Of 376 articles, only 20 met the inclusion criteria of the study. The family household characteristics included individual factors (sex age, history of diarrhea, and birthplace), family factors (family headship, primary caregiver/mother, social-cultural orientation, and family system factors), and environmental factors. Various child variables, family factors, and environmental factors (the type of home, floor type, water access, source of drinking water, and household electricity) were identified as being associated with stunting. Therefore, these factors should be evaluated to prevent and control stunting, and they should be incorporated into health programs targeting stunting.
Comparative Study of Machine Learning Models for Bee Colony Acoustic Pattern Classification on Low Computational Resources

In precision beekeeping, the automatic recognition of colony states to assess the health status of bee colonies with dedicated hardware is an important challenge for researchers, and the use of machine learning (ML) models to predict acoustic patterns has increased attention. In this work, five classification ML algorithms were compared to find a model with the best performance and the lowest computational cost for identifying colony states by analyzing acoustic patterns. Several metrics were computed to evaluate the performance of the models, and the code execution time was measured (in the training and testing process) as a CPU usage measure. Furthermore, a simple and efficient methodology for dataset prepossessing is presented; this allows the possibility to train and test the models in very short times on limited resources hardware, such as the Raspberry Pi computer, moreover, achieving a high classification performance (above 95%) in all the ML models. The aim is to reduce power consumption and improves the battery life on a monitor system for automatic recognition of bee colony states.