Miracle-dz/UniFAR-FTUs huggingface dataset:
Designing a phantom for dose evaluation in multi-slice CT

Accurately representing radiation dose delivered in MSCT is becoming a concern as the maximum beam width of some modern CT scanners tends to become wider than the 100 mm charge-collection length of the pencil ionization chamber generally used in CT dosimetry. We investigate two alternative methods of dose evaluation in CT scanners. We investigate two alternative approaches for better characterization of CT dose than conventional evaluation of CTDI100. First, we simulate dose profiles and energy deposition in phantoms longer than the typically used 14-15 cm length right-circular cylinders. Second we explore the accuracy and practicality of applying mathematical convolution to a scatter kernel in order to generate dose profiles. A basic requirement for any newly designed phantom is that it be able to capture approximately the same dose as would an infinitely long cylinder, but yet be of a size and weight that a person could easily carry and position. Using the PENELOPE Monte Carlo package, we simulated dose profiles in cylindrical polymethyl methacrylate (PMMA) phantoms of 10, 16, 20, 24 and 32 cm diameter and 15, 30 and 300 cm length. Beam widths were varied from 1 cm to 60 cm. Lengths necessary to include within the dose integrals values associated with the scatter tails as well as with the primary radiation of the profile were then calculated as the full width at five percent of maximum dose. The resulting lengths suggest that to accommodate wide beam widths, phantoms longer than those currently used are necessary. The results also suggest that using a longer phantom is a relatively more accurate approach, while using mathematical convolution is simpler and more practical to implement than using the long phantoms designed according to direct Monte Carlo simulations.
Commission 4: Progress in Magnetospheric Radio

Since the last report was written (in the spring of 1966), there has been a remarkable advance in our knowledge and understanding of the structure and behavior of the magnetosphere, especially with regard to the fundamental problems of the aurora and geomagnetic storms. The average structure of the quiet magnetosphere has been studied in considerable detail [Ness et al., 1966; Spieser and Ness, 1967; Behannon, 1968; Fairfield, 1968; Mihalov et al., 1968], and it has been shown that the tail and ‘neutral’ sheet extend well past the moon, and possibly to much greater distances [Ness et al., 1967]. The nature of the changes that occur in the geomagnetic field during disturbed periods has been observed, especially by magnetometers on the geostationary satellite ATS 1 [Brown et al., 1968; Cummings et al., 1968; Cummings and Coleman, 1968]. It has been found that the ring current, which is usually situated between 3 and about 10 RE depending on the degree of geomagnetic activity, commonly has a pronounced asymmetric component, with the maximum inflation of the geomagnetic field occurring in the evening sector.
Impedance acoustic cloaking

The paper addresses a new approach to passive acoustic cloaking, which is an alternative to the well-known approach of transformation optics. It is shown first that the scattered acoustic field of a body is completely determined by special surface impedances defined at the body surface. The surface impedances of a non-scattering, i.e. acoustically transparent, body of any geometry are then derived explicitly, and a thin coating is proposed that can provide such impedances with controlled accuracy. The coating represents a doubly periodic surface structure made of elements of sub-wavelength size. The computer simulation shows that the coating being placed on any body can render it non-scattering and, hence, invisible to all acoustic observation systems in a range of low and medium frequencies. The width of the range and the coating efficiency depend on the number of internal couplings introduced between the coating elements.
Nanoscale elastic-property measurements and mapping using atomic force acoustic microscopy methods

We describe a dynamic atomic force microscopy (AFM) method for measuring the elastic properties of surfaces, thin films and nanostructures at the nanoscale. Our approach is based on atomic force acoustic microscopy (AFAM) techniques and involves the resonant modes of the AFM cantilever in contact mode. From the frequencies of the resonant modes, the tip–sample contact stiffness k* can be calculated. Values for elastic properties such as the indentation modulus M can be determined from k* with appropriate contact-mechanics models. We present the basic principles of AFAM and explain how it can be used to measure local elastic properties with a lateral spatial resolution of tens of nanometres. Quantitative results for a variety of films as thin as 50 nm are given to illustrate our methods. Studies related to measurement accuracy involving the effects of film thickness and tip wear are also described. Finally, we discuss the design and use of electronics to track the contact-resonance frequency. This extension of AFAM fixed-position methods will enable rapid quantitative imaging of nanoscale elastic properties.
Ground-based Mid-Infrared Spectroscopy of Faint Standard Stars in the North Ecliptic Polar Region for the ASTRO-F Infrared Camera

Faint standard stars in the mid-infrared region (less than a few hundred millijanskys at 9 μm) are required for the on-orbit calibration of the Infrared Camera (IRC) on board ASTRO-F because of its high sensitivity, as well as the small dynamic range. Mid-infrared low-resolution (λ/Δλ ∼ 250) spectra of six faint K and M giant stars (70-180 mJy at 9 μm, K1.5-M0 III), which are located in the north ecliptic polar region and are thus suitable for calibrators for the IRC, are obtained by using the Cooled Mid-Infrared Camera and Spectrometer (COMICS) on the Subaru telescope to test the faint-infrared standard-star network recently constructed for space-borne instruments. The spectra are directly calibrated relative to Vega (A0 V). The present results indicate that the spectra of the faint standard K-M0 giant stars show good agreement with those predicted in the standard network within 10% accuracy on average. The overall spectral shapes are also in agreement with the predictions. In particular, the observed SiO absorption feature in the 8 μm region matches well with the prediction for an M0 III star. The present observations directly connect a primary standard calibrator (Vega) to faint K giant calibrators of the network in the 10 μm region and validate several faint (∼0.1 Jy) members of the standard-star network for the first time. Absolute calibrations are provided for five of the medium-band filters of the COMICS instrument in the 10 μm window.
Magnetically induced vibration in a permanent-magnet brushless DC motor with symmetric pole-slot configuration

The paper reports a numerical and experimental study of magnetically induced vibration associated with rotor/stator eccentricity and imperfect magnetization for 8-pole 6-slot symmetric brushless dc (BLDC) motors. Magnetic forces and cogging torque are calculated for various slot angles by using the finite-element method (FEM). The results show that there is an optimal slot angle for minimum cogging torque, but this slot angle is not optimal for reducing magnetic forces. In the idle acoustics test, the motors with reduced magnetic forces show clear reduction at the expected frequencies while the motors with minimum cogging torque show no change at the cogging torque frequency, which implies unbalanced magnetic forces have greater effect on actual vibration of the spindle motor than cogging torque. The results show that the proper direction in motor design is to reduce unbalanced magnetic forces when both cogging torque and unbalanced magnetic forces are not achievable simultaneously.
The theory of sink strengths

A formal derivation of the sink strengths to be used in point defect rate theory is presented. Previous models that have been invoked for the approximate evaluation of these parameters are discussed. It is shown that the effective medium approach, as introduced earlier by us, constitutes the best available approach for steady state problems. Sink strengths for voids, straight (and parallel) dislocations, dislocation loops and grain boundaries are considered. It is shown that most recent criticisms of the effective medium method are groundless.
INTERACTION BETWEEN MULTIPLE MODES IN MILLING PROCESSES

The productivity of many industrial cutting processes is limited by high amplitude chatter vibrations. An optimization technique based on the use of the stability lobes helps to increase the productivity of these processes, improving the life of machine elements and reducing the tool wear as well. The best-known lobes correspond to Hopf bifurcations. However, in case of interrupted cutting, additional lobes appear due to period doubling or flip bifurcation. When the system has more than one dominant vibration mode, important variations can appear in stability due to interaction between modes. The basic mathematics for the appearance of these new lobes are shown in this article. The frequency domain study shows that lobes related to flip bifurcation are a special case of the interaction between modes. The results of these interactions are verified by comparison with semi-discretization method and time domain simulations, respectively.
Time Domain Electromagnetic Field Computation with Finite Difference Methods

The solution of Maxwell's equations in the time domain has now been in use for almost three decades and has had great success in many different applications. The main attraction of the time domain approach, originating in a paper by Yee (1966), is its simplicity. Compared with conventional frequency domain methods it takes only marginal effort to write a computer code for solving a simple scattering problem. However, when applying the time domain approach in a general way to arbitrarily complex problems, many seemingly simple additional problems add up. We describe a theoretical framework for solving Maxwell's equations in integral form, resulting in a set of matrix equations, each of which is the discrete analogue to one of the original Maxwell equations. This approach is called Finite Integration Theory and was first developed for frequency domain problems starting about two decades ago. The key point in this formulation is that it can be applied to static, harmonic and time dependent fields, mainly because it is nothing but a computer-compatible reformulation of Maxwell's equations in integral form. When specialised to time domain fields, the method actualy contains Yee's algorithm as a subset. Further additions include lossy materials and fields of moving charges, even including fully relativistic analysis. For amny practical problems the pure time domain algorithm is not sufficient. For instance a waveguide transition analysis requires knowledge of the incoming and outgoing mode patterns for proper excitation in the time domain. This is a typical example where both frequency and time domian analysis are essential and only the combinatin yields the successful result. Typical engineers may wonder why at all one should apply time domain analysis to basically monochromatic field problems. The answer is simple: it is much faster, needs less computer memory, is more general nad typically more accurate. Speed-up factors of over 200 have been reached for realistic problems in filter and waveguide design. The small core space requirement makes time domain methods applicable on desktop computers using milions of cells, and six unknowns per cell—a dimension that has not yet been reached by frequency domain approaches. This enormous amount of mesh cells is absolutely neceesary when complex structures or structures with spacial dimensions of many wavelengths are to be studied. Our personal recod so far is a waveguide problem in which we used 72,000,000 unknowns.
Thermodynamic constraints on a time-dependent Lambda model (cosmology)

The general expression for the entropy production in cosmologies with variable effective cosmological 'constant' ( Lambda ) is presented. By assuming that Lambda decays as Lambda = alpha R-m+ beta (R/R)2, where R(t) is the scale factor of the FRW models, the second law of thermodynamics and the Landau-Lifshitz theory for non-equilibrium fluctuations are used to establish constraints on the parameters alpha , beta and m.
Theory and experiment of circularly polarized dielectric resonator antenna with a parasitic patch

The use of a single parasitic patch for circular polarization (CP) excitation of the dielectric resonator antenna (DRA) is investigated. For demonstration, the technique is applied to the conformal-strip fed hemispherical DRA, excited at the fundamental TE/sub 111/ mode. Using the Green's function approach, the integral equations for the conformal-strip and parasitic-patch currents are formulated by matching the appropriate boundary conditions. The equations are then solved using the method of moments (MoM). In using the MoM, both the rigorous and simplified current expansions are used for the parasitic patch, and their results are compared with each other. In each case, the impedance integrals are evaluated by virtue of newly obtained recurrence formulas and direct analytical integration. Hence, the results can be calculated very efficiently without the need for any numerical integration, which greatly facilitates the numerical implementation. The input impedance, axial ratio, and radiation patterns of the CP DRA are calculated, and the results are in good agreement with measurements.
Evaluation of gross radioactivity in foodstuffs

Abstract The paper presents the results of radiological investigations of food products sampled in the summer and fall of 2011 and 2012 in different parts of Van, Turkey. Gross radioactivity measurements in food products were evaluated. Food items were divided into eight groups: (1) water, (2) fish, (3) cheese products, (4) fruits, (5) vegetables, (6) herbs, (7) walnut and (8) rock salt. The levels of the gross alpha and gross beta radioactivity in all food samples varied widely ranging from 0.070 to 10.885 Bq/g and from 0.132 to 48.285 Bq/g on dry mass basis, respectively. In one sample, gross alpha and gross beta activity concentrations were found to be relatively high according to the other samples and in all samples, the gross alpha radioactivity was measured lower than the gross beta radioactivity. The gross α and gross β activities were measured by using α/β counter of the multi-detector low background system (PIC MPC-9604).
Pulsed Laser Deposition and Characterization of Bi 4− x Nd x Ti3O 12 Thin Films

Since the discovery of fatigue free La doped Bi4Ti3O12 films, considerable interest has been shown in studying the effects of various other rare earth dopants (e.g. Nd, Sm) on the ferroelectric properties of this material for applications in non-volatile ferroelectric random access memories. We have grown Nd-doped films from a ceramic target of composition Bi3.15Nd0. 85Ti3O12 by pulsed laser ablation. Epitaxial films (c-axis and non-c-axis oriented) have been grown on strontium titanate substrates of different crystallographic orientations to study the effect of film orientation on ferroelectric properties. Films have been characterized using X-ray diffraction. Ferroelectric measurements have been performed to investigate the dependence of film properties on crystallographic orientation. †Paper originally presented at 10th European Meeting on Ferroelectricity, Cambridge, U.K., August 3–8, 2003.
Nocturnal low‐level jet and ‘atmospheric streams’ over the rain shadow region of Indian Western Ghats

Spatial and temporal characteristics of a nocturnal low‐level jet (LLJ) on the east side of the Western Ghat mountain range over India's west coast and processes leading to the formation of the jet are discussed. The boundary‐layer jet has a regional scale extent, as revealed by high‐resolution Advanced Research Weather Research and Forecasting (ARW) model simulations, and contributes to the formation of ‘atmospheric streams’ of water vapor over the selected land regions. Simulations indicate that the formation of LLJ is mainly attributed to the baroclinicity of the valley atmosphere due to the gently rolling terrain, which is assisted by the persistence of an unstable residual layer above the developing stable boundary layer in the valley and cooling over the slopes. Prior to the formation of LLJ, the boundary layer is dominated by deep roll circulations. The LLJ followed a gust front zone associated with a mountain wave. The low‐level flow below the jet is decoupled from the upper‐level flow as a result of strong vorticity below the jet and suppression of turbulence at the jet core. A conceptual model for the boundary layer interactions, dynamics of the mountain wave, LLJ, etc. are proposed for Western Ghat region. Copyright © 2011 Royal Meteorological Society
Computer simulation of wave scattering from three-dimensional conducting random surfaces

Numerical simulation studies had been carried out by the conjugate gradient method to compute the solutions of the field integral equation for three-dimensional, perfectly conducting, Gaussian, random rough surfaces. The rate of convergence of the conjugate gradient method was fundamentally controlled by the root mean square (rms.) surface slope. Solutions computed using this method result in a significant reduction in CPU running time compared to those using direct methods, such as the Gaussian Elimination method. The validity of the numerical results of backscattering coefficients is verified by comparing simulation results with Kirchhoff theory, small perturbation theory, and Integral Equation methods at their valid regions. The efficiency and versatility of the numerical simulation algorithm as a practical tool to study rough surface scattering is demonstrated.
Mean field dynamics of a Wilson–Cowan neuronal network with nonlinear coupling term

In this paper we prove the propagation of chaos property for an ensemble of interacting neurons subject to independent Brownian noise. The propagation of chaos property means that in the large network size limit, the neurons behave as if they are probabilistically independent. The model for the internal dynamics of the neurons is taken to be that of Wilson and Cowan, and we consider there to be multiple different populations. The synaptic connections are modeled with a nonlinear “electrical” model. The nonlinearity of the synaptic connections means that our model lies outside the scope of classical propagation of chaos results. We obtain the propagation of chaos result by taking advantage of the fact that the mean-field equations are Gaussian, which allows us to use Borell’s Inequality to prove that its tails decay exponentially.
Extended gas in Seyfert 2 galaxies: implications for the nuclear source

We use long-slit spectroscopic optical data to derive the properties of the extended emitting gas and the nuclear luminosity of a sample of 18 Seyfert 2 galaxies. From the emissionline luminosities and ratios we derive the density, reddening and mass of the ionized gas as a function of distance up to 2‐4 kpc from the nucleus. Taking into account the geometric dilution of the nuclear radiation, we derive the radial distribution of covering factors and the minimum rate of ionizing photons emitted by the nuclear source. This number is an order of magnitude larger than that obtained from the rate of ionizing photons ‘intercepted’ by the gas and measured from the Hα luminosity. A calibration is proposed to recover this number from the observed luminosity. The He II λ4686/Hβ line ratio was used to calculate the slope of the ionizing spectral energy distribution (SED), which in combination with the number of ionizing photons allows the calculation of the hard X-ray luminosities. These luminosities are consistent with those derived from X-ray spectra in the eight cases for which such data are available and recover the intrinsic X-ray emission in Compton-thick cases. Our method can thus provide reliable estimates of the X-ray fluxes in Seyfert 2 galaxies for the cases where it is not readily available. We also use the ionizing SED and luminosity to predict the infrared luminosity under the assumption that it is dominated by reprocessed radiation from a dusty torus, and find a good agreement with the observed IRAS luminosities.
Always happy: an ideal is reproduced and challenged in hairdresser vocational education and training

ABSTRACT In the hairdressing occupation emotional labour has often come to overshadow other vocational skills. The present study, using ethnographic methods, explores how students and teachers in vocational education and training (VET) for hairdressers in Sweden describe and explain the emotional labour being carried out when a hairdresser perform good service. The results show that to look happy and smile has a central position in students’ and VET teachers’ descriptions of how an ideal service worker is expected to act. A positive attitude and a special voice are other signs that characterise the hairdresser who provides good service. The happy ideal is both reproduced and challenged from students in the hairdresser education. One conclusion is that an ideal service worker reinforces femininity norms to act as a professional, which is in line with the requirements of the hairdresser education and the customer’s and employers’ expectations. At the same time, the happy ideal limits students’ opportunities to challenge and question prevailing power structures, which is also part of the Swedish upper secondary school mission.
3 s-wave : isotropic gap Nematics : anisotropic gap Magnets : point nodes ( Weyl fermions ) d-wave pairings : two line nodes

We compute the effects of electronic interactions on gapless spin-3/2 excitations that in a noninteracting system emerge at a bi-quadratic touching of Kramers degenerate valence and conduction bands in three dimensions, also known as a Luttinger semimetal. This model can describe the low-energy physics of HgTe, gray-Sn, 227 pyrochlore iridates and half-Heuslers. For the sake of concreteness we only consider the short-range components of the Coulomb interaction (extended Hubbardlike model). By combining mean-field analysis with a renormalization group (RG) calculation (controlled by a “small” parameter , where = d−2), we construct multiple cuts of the global phase diagram of interacting spin-3/2 fermions at zero and finite temperature and chemical doping. Such phase diagrams display a rich confluence of competing orders, among which rotational symmetry breaking nematic insulators and time reversal symmetry breaking magnetic orders (supporting Weyl quasiparticles) are the prominent candidates for excitonic phases. We also show that even repulsive interactions can be conducive to both mundane s-wave and topological d-wave pairings. The reconstructed band structure (within the mean-field approximation) inside the ordered phases allows us to organize them according to the energy (entropy) gain in the following (reverse) order: s-wave pairing, nematic phases, magnetic orders and d-wave pairings, at zero chemical doping. However, the paired states are energetically superior over the excitonic ones for finite doping. The phase diagrams obtained from the RG analysis show that for sufficiently strong interactions, an ordered phase with higher energy (entropy) gain is realized at low (high) temperature. In addition, we establish a “selection rule” between the interaction channels and the resulting ordered phases, suggesting that repulsive short-range interactions in the magnetic (nematic) channels are conducive to the nucleation of d-wave (s-wave) pairing among spin-3/2 fermions. We believe that the proposed methodology can shed light on the global phase diagram of various two and three dimensional interacting multi-band systems, such as Dirac materials, doped topological insulators and the like.