Double Scaling Research Articles

Austenite to Ferrite Transformation Kinetics in Fe-9 %Cr Alloys - I. General Kinetic Analysis

The paper considers theoretical aspects of the kinetics of austenite → ferrite transformation in an Fe–9 %Cr alloy, a common model of diffusionless transformation. In previous studies it was shown that this transformation under isothermal conditions shows a behaviour typical for nucleation site saturation, including the change of the Avrami exponentn(determined as the slow of transformation curve on double logarithmic scale) from 4 to 1. Activation energies determined in two ways: by the ‘nose’ temperature of the normal C-curve and by the slope of the C-curve re-drawn on a reverse temperature scale are unexpectedly similar (272–315 kJ/mole) and not temperature-dependent. But the complete TTT diagrams calculated using these values determined directly from experimental data and the precise formula of Cahn’s solution of grain face nucleated transformation problem do not provide good agreement with experiment in the whole temperature range. This may mean that the theory of site saturation needs some correction.

Argyres-Douglas theories, Painlev\xe9 II and quantum mechanics

We show in details that the all order genus expansion of the two-cut Hermitian cubic matrix model reproduces the perturbative expansion of the H1 Argyres-Douglas theory coupled to the Ω background. In the self-dual limit we use the Painlevé/gauge correspondence and we show that, after summing over all instanton sectors, the two-cut cubic matrix model computes the tau function of Painlevé II without taking any double scaling limit or adding any external fields. We decode such solution within the context of transseries. Finally in the Nekrasov-Shatashvili limit we connect the H1 and the H0 Argyres-Douglas theories to the quantum mechanical models with cubic and double well potentials.

Double scaling limit of mathcal{N} = 2 chiral correlators with Maldacena-Wilson loop

We consider mathcal{N} = 2 conformal QCD in four dimensions and the one-point correlator of a class of chiral primaries with the circular frac{1}{2} -BPS Maldacena-Wilson loop. We analyze a recently introduced double scaling limit where the gauge coupling is weak while the R-charge of the chiral primary Φ is large. In particular, we consider the case Φ = (Trφ2)n, where φ is the complex scalar in the vector multiplet. The correlator defines a non-trivial scaling function at fixed κ = ngYM2 and large n that may be studied by localization. For any gauge group SU(N) we provide the analytic expression of the first correction ~ ζ(3)κ2 and prove its universality. In the SU(2) and SU(3) theories we compute the scaling functions at order mathcal{O} (κ6). Remarkably, in the SU(2) case the scaling – function is equal to an analogous quantity describing the chiral 2-point functions leftlangle Phi overline{Phi}rightrangle in the same large R-charge limit. We conjecture that this SU(2) scaling function is computed at all-orders by a mathcal{N} = 4 SYM expectation value of a matrix model object characterizing the one-loop contribution to the 4-sphere partition function. The conjecture provides an explicit series expansion for the scaling function and is checked at order mathcal{O} (κ10) by showing agreement with the available data in the sector of chiral 2-point functions.

Oxidation behavior of austenitic steel Sanicro25 and TP347HFG in supercritical water

Oxidation tests of austenitic steel Sanicro25 and TP347HFG were implemented at 600–700 °C in supercritical water under 25 MPa without dissolved oxygen. With an increase in temperature, the weight change of TP347HFG steel increases significantly while the weight change of Sanicro25 increases relatively slow. A double layer oxide scale formed on TP347HFG and Sanicro25 steel, which was composed of Fe‐rich oxide layer and a Cr‐rich inner oxide layer. Small amount of Cr2O3 was observed for TP347HFG but a continuous Cr2O3 formed at interface of oxide and matrix for Sanicro25 at 600 and 700 °C. Furthermore, Fe2O3 is detected at 600–700 °C for Sanicro25. The effect mechanism of temperature and the Cr content on oxidation rate and oxide composition were discussed.

Sexual Double Standard, Dating Violence Recognition, and Sexual Assertiveness among University Students in South Korea

PurposeThis study aimed to examine the association among sexual double standard, dating violence recognition, and sexual assertiveness among Korean university students. MethodsUsing a cross-sectional survey study in January 2018, Korean university students (N = 322, years; 54.3% female) completed structured questionnaires with the double standard scale, dating violence recognition index, and sexual assertiveness index. The relationship among the variables was analyzed with Pearson's correlations and multiple regression analyses. ResultsThere were significant correlations among sexual double standard, dating violence recognition, and sexual assertiveness. Sexual double standard (β = .12, p = .043) was determined to influence dating violence recognition. In addition, gender (β = .63, p < .001) and sexual double standard (β = .11, p = .015) were determined to influence dating violence recognition; the explanatory power was 43%. ConclusionThese findings will serve as a basis for the development of education programs that help university students to establish appropriate sexual values and enjoy a healthy sex life.

Discrete Painlevé system and the double scaling limit of the matrix model for irregular conformal block and gauge theory

We study the partition function of the matrix model of finite size that realizes the irregular conformal block for the case of the N=2 supersymmetric SU(2) gauge theory with Nf=2. This model has been obtained in arXiv:1008.1861 [hep-th] as the massive scaling limit of the β-deformed matrix model representing the conformal block. We point out that the model for the case of β=1 can be recast into a unitary matrix model with log potential and show that it is exhibited as a discrete Painlevé system by the method of orthogonal polynomials. We derive the Painlevé II equation, taking the double scaling limit in the vicinity of the critical point which is the Argyres–Douglas type point of the corresponding spectral curve. By the 0d-4d dictionary, we obtain the time variable and the parameter of the double scaled theory respectively from the sum and the difference of the two mass parameters scaled to their critical values.

QFM Signals Parameters Estimation Based on Double Scale Two Dimensional Frequency Distribution

This paper proposes a novel estimation method, named double scale two dimensional frequency distribution (DSTFD), to estimate the parameters of quadratic frequency modulated (QFM) signals. In the DSTFD, by using a novel parametric instantaneous self-correlation function and the idea of the keystone transform, the QFM signals are transformed into two-dimensional frequency domain, and the QFM signals are detected by searching peaks. To reduce computational cost, a double scale (DS) estimation strategy, which consists of coarse estimation and fine estimation, is proposed. The DS estimation strategy can be implemented by using the Chirp Z-transform and an improved transform named local scaled Fourier transform (LSFT). The LSFT only consists of complex multiplications, fast Fourier transform (FFT), and inverse FFT operations. The implementation, anti-noise performance, and computational cost are analyzed for the proposed method. Through simulations and analyses, the results demonstrate that the DSTFD outperforms other compared algorithms.

The Hankel determinant associated with a singularly perturbed Laguerre unitary ensemble

We are concerned with the probability that all the eigenvalues of a unitary ensemble with the weight function \\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$w(x;1) = {x^\\alpha }{e^{ - x - {1 \\over x}}},x \\in [0,\\infty )$$\\end{document}, α > −1, t ≥ 0, are greater than s. This probability is expressed as the quotient of Dn(s,t) and its value at s = 0, where Dn(s,t) denotes the determinant of the n dimensional Hankel matrices generated by the moments of w(x;t) on x ∈ [s,∞). In this paper we focus specifically on the Hankel determinant Dn(s,t) and its properties.Based on the ladder operators adapted to the monic polynomials orthogonal with respect to w(x;t), and from the associated supplementary conditions and a sum-rule, we show that the log-derivative of the Hankel determinant, viewed as a function of s and t, satisfies a second order sixth degree partial differential equation, where n appears as a parameter. In order to go to the thermodynamic limit, of infinitely large matrices, we envisage a scenario where n → ∞, s → 0, and t → 0 such that S := 4ns and T := (2n + 1 + α)t are finite. After such a double scaling, the large finite n equation reduces to a second order second degree equation, in the variables S and T, from which we derive the asymptotic expansion of the scaled Hankel determinant in three cases of S and T: S → ∞ with T fixed, S → 0 with T > 0 fixed, and T → ∞ with S > 0 fixed. The constant term in the asymptotic expansion is shown to satisfy a difference equation and one of its solutions is the Tracy-Widom constant.

Study of Hydrogen Peroxide Vapors Sensors Based on Carbon Nanotubes Coated with Tin Oxide Nanoparticles

We present the results of studies of the nanocomposite MWCNTs/SnO2 hydrogen peroxide vapor sensors. The technology of manufacturing of these sensors has been developed. Because of the measurements of the temperature characteristics, the 100°C optimal operating temperature of the studied sensors has been found. The response and recovery curves of the sensors were investigated in the presence of different concentrations of hydrogen peroxide vapor in the atmosphere. A sufficiently high response was registered already at close to the threshold low concentrations of the target gas present in the air. In a double logarithmic scale, the linear dependence of the sensors response on the concentration of hydrogen peroxide vapor was observed in a certain concentration range. The minimal registered gas concentration is less than 1 ppm.

Wettability of zinc oxide nanorod surfaces.

In this work, we have studied the wettability of zinc oxide (ZnO) nanorods grown on fluorine-doped tin oxide (FTO) by highlighting the effect of polar and non-polar ZnO facets on contact angle (CA) results. The variation in the wettability behaviors of the synthesized surfaces is mainly related to physical and chemical surface texturing which influenced the liquid drop penetration. Indeed, three main penetration states can be deduced: total, partial, and null-penetration. Where, low CA (100.9°) with high contact angle hysteresis (CAH) (13°) is observed for total penetration of the liquid drop. While, high CA (139.6°) with low CAH (7°) is observed for null-penetration. Moreover, we have found that the chemical texturing of ZnO, especially the hydrophilicity of ZnO tips, responsible for liquid drop sticking, prevents the liquid slipping over the surface. In order to promote the liquid rolling on the ZnO surface, we reported the physical modification of the ZnO structures. Therefore, the rolling of the liquid drop on the inclined surface of ZnO is achieved by using a new structure based on double scale roughness. This surface exhibits superhydrophobic behavior with a CA of 153° and CAH of 3°.

The Sea Mile and Nautical Mile in Marine Navigation

The problem of differences between the sea mile and the international nautical mile has been analysed. Algorithms for the calculation of sea miles with applications in different sailing methods on the ellipsoid that can be easily incorporated in modern microprocessor controlled navigational devices are proposed. These algorithms can also be employed on an outfit of large-scale nautical charts with a double scale in sea miles and international nautical miles.

The k-tacnode process

The tacnode process is a universal behavior arising in nonintersecting particle systems and tiling problems. For Dyson Brownian bridges, the tacnode process describes the grazing collision of two packets of walkers. We consider such a Dyson sea on the unit circle with drift. For any \(k\in \mathbb {Z}\), we show that an appropriate double scaling of the drift and return time leads to a generalization of the tacnode process in which k particles are expected to wrap around the circle. We derive winding number probabilities and an expression for the correlation kernel in terms of functions related to the generalized Hastings–McLeod solutions to the inhomogeneous Painleve-II equation. The method of proof is asymptotic analysis of discrete orthogonal polynomials with a complex weight.

Double scaling and master curve to predict Kts for elliptically notched orthotropic plates from Kts in circularly notched isotropic plates

The key role played by the so-called stress concentration factors (symbolically usually referred to as Kts) while performing either analysis or design in both mechanical engineering and structural engineering is a well-proven fact; hence, the corresponding accuracy and ease of determination in their estimation have critical implications related to engineering matters. In a previous work, we showed that starting with the Kts for rectangular isotropic plates with circular holes the Kts for rectangular orthotropic plates with elliptic holes can be easily and accurately predicted, using a double scaling procedure (a geometric scaling and a material scaling) together with a basic Kt curve employed as a master curve. In the present work we investigate, in an engineering heuristic manner, whether the stated double scaling procedure exhibits a more general structure so that it can accurately be applied to different plate stress raiser geometries. Specifically, we examine if starting with the known Kts for rectangular isotropic plates with circular notches, used as a master curve, the Kts for orthotropic plates with elliptic notches can be easily and accurately predicted as well. Using a simple hand calculator, we show that the resulting proposed set of predicting mathematical expressions makes virtually unnecessary the use of complex numerical programs (FEM based for example) to determine the corresponding Kts, producing at the same time accurate results with a maximum average recorded error of 2.59%. Additionally, given that a Kt predictive procedure for holed plates was presented in our previous work, and for notched plates in this work, we found necessary first to examine the hypothesis that suggests using Kts from holed plates as good approximations for Kts for notched ones and vice versa. We found this hypothesis not to be valid for either isotropic or orthotropic plates. In the course of this work it was found, rather significantly, that the well-known double square root material contribution to Kts is valid for both holed plates as well as notched ones.

Research on Interfacial Reaction and Growth Behavior of Intermetallic Compound of Dip-Soldered Sn/Ni System

Interfacial reaction and the growth behavior of intermetallic compound (IMC) between Sn solder and Ni substrate by dip soldering under different aging conditions (120 °C, 170 °C and 200 °C) by using scanning electron microscope were investigated. Experimental results showed that the only scallop-shaped Ni3Sn4 IMC layer formed at the interface after aging process and the thickness of IMC layer increased with prolonged aging time. Moreover, the cracks formed in the interface between IMC and solder could be resulted from the residual stress caused by the difference in thermal expansion coefficients. In addition, the spalling behavior of IMC from substrate was caused by cyclic shear stresses and strains induced and the morphological changes in IMC formation. During the aging process, it was found that the thickness of IMC always had a linear relationship with the square root of aging time under different aging temperatures (120 °C, 170 °C and 200 °C). The growth rate constants of IMC layers aged at 120 °C, 170 °C and 200 °C were obtained by using fitting method from the experimental data, which were 4.65 × 10−18 m2 s−1, 9.94 × 10−18 m2 s−1 and 1.76 × 10−16 m2 s−1, respectively. Based on these data, the activation energy of IMC layer was determined to be 63.23 kJ/mol. Likewise, the mean diameter of IMC grains increased with the increase in aging time. It is suggested that the mean diameter of IMC grains was always plotted against the aging time on a double logarithmic scale under different aging temperatures. The time rate constants of IMC grains aged at 120 °C, 170 °C and 200 °C were obtained by using same method, which were 0.10, 0.27 and 0.26, respectively.

Multiscale analysis of membrane instability by using the Arlequin method

This work aims at developing a multiscale model by combining the Fourier-related double scale analysis and the bridging domain method to study membrane instabilities. Towards this end, a Fourier reduced membrane model is firstly established based on the Föppl-Von Karman plate equations, where the initial unknowns are expanded into Fourier series and replaced by their Fourier coefficients. As the latter varies much more slowly than the initial functions, the computational efficiency of the reduced model is significantly improved. However, the boundary effects could not be accurately captured because the prescription of boundary conditions is always questionable in any reduced models. Thus, there is a need to develop a multiscale model, where the full shell model is used near boundaries to capture the local effects, and the Fourier reduced model is used in the rest to reduce the computational cost. These two models are then bridged by the Arlequin method, which permits to couple different mechanical models by Lagrange multipliers. Finally, the proposed multiscale model is implemented into ABAQUS as the user element (UEL) to extend its applicability for more complex membrane instabilities. Numerical results show that this multiscale model is able to simulate the membrane instabilities with high efficiency and accuracy.

Oxidation characteristics of porous Ni-12 wt%Cr alloy at 1000 °C in air

Abstract The oxidation kinetics of porous Ni-12 wt%Cr alloy with 23.7% porosity was investigated for 100 h at 1000 °C in air. The phases forming the oxide scale were determined by using X-ray diffractometry. The topography of the surface of the oxide scale and the microstructure of the cross-section of the oxide scale were investigated by utilizing optical and scanning electron microscopy and X-ray energy dispersive analysis. The oxidation rate was initially rapid and then it gradually decreased to lower values over a period of about 24 h until realizing the steady-state condition with linear rate constant of about 3.7 × 10−8 g/m2 sec. Double multilayered porous scale of NiO-Cr2O3 sublayers with internal precipitates of nickel spinel within the NiO layers was formed. The growth of the double multilayer scale was explained on the basis of inward migration of molecular oxygen.

Painlevé transcendents and the Hankel determinants generated by a discontinuous Gaussian weight

This paper studies the Hankel determinants generated by a discontinuous Gaussian weight with one and two jumps. It is an extension in a previous study, in which they studied the discontinuous Gaussian weight with a single jump. By using the ladder operator approach, we obtain a series of difference and differential equations to describe the Hankel determinant for the single jump case. These equations include the Chazy II equation, continuous and discrete Painlevé IV. In addition, we consider the large n behavior of the corresponding orthogonal polynomials and prove that they satisfy the biconfluent Heun equation. We also consider the jump at the edge under a double scaling, from which a Painlevé XXXIV appeared. Furthermore, we study the Gaussian weight with two jumps and show that a quantity related to the Hankel determinant satisfies a two variables' generalization of the Jimbo‐Miwa‐Okamoto σ‐form of the Painlevé IV.

Measuring gender norms about relationships in early adolescence: Results from the global early adolescent study

IntroductionGender norms are increasingly recognized as drivers of health and wellbeing. While early adolescence constitutes a critical window of development, there is limited understanding about how adolescents perceive gender relations across different cultural settings. This study used a mixed-method approach, grounded in the voices of young people around the world, to construct and test a cross-cultural scale assessing the perceptions of gender norms regulating romantic relationships between boys and girls in early adolescence. MethodsThe study draws on the Global Early Adolescent study (GEAS), a study focusing on gender norms and health related outcomes over the course of adolescence in urban poor settings worldwide. In-depth interviews were first conducted among approximately 200 adolescents between 10–14 years in seven sites across 4 continents to identify common scripts guiding romantic relations in early adolescence. These scripts were then transformed into a multidimensional scale. The scale was tested among 120 adolescents in each of 14 GEAS sites, followed by a second pilot among 75 adolescents in six sites. We evaluated the psychometric criteria of each sub-scale using principal component analysis, and parallel analysis, followed by exploratory factor analysis to guide the selection of a more parsimonious set of items. ResultsResults suggested a two-factor structure, consisting of an “adolescent romantic expectations” subscale and a “Sexual Double Standard” subscale. Both subscales yielded high internal validity in each site, with polychoric Cronbach alpha values above 0.70 with the exception of Kinshasa for the adolescent romantic expectations scale (0.64) and Hanoi for the sexual double standard scale (0.61). ConclusionThis study reveals common perceptions of gendered norms about romantic engagement in early adolescence, normative for both sexes, but socially valued for boys while devaluated for girls. The findings illustrate that social hierarchies of power in romantic relationships form early in adolescence, regardless of cultural setting.

English

Wheat is the 2nd most important culture in the world.&nbsp; Septoria leaf blotch is one of the most important wheat diseases. It is caused by Mycosphaerella graminicola (an: Zymoseptoria tritici). The aim of this study is to evaluate the presence and the importance of this disease in Algeria. A collection of 625 isolates was made through the years (2010, 2011, and 2013). Isolates were collected from the Algerian zones of cereal production. Phenotypic and genetic characterization via morphological, cultural and pathogenic analysis showed the presence of Septoria leaf blotch in 72 fields (from 122) in 20 departments (counties). In some fields the disease is highly frequent with an index of 99 according to double digit scale. Two main types of isolates were found; but the yeast-like form dominated with 94.08%. 26 isolates sampled from 25 fields were tested to evaluate isolates aggressiveness variability. Only 2 isolates from 26 inoculated were able to produce symptoms on three cereal species (triticale, durum and bread wheat). Key words: Zymoseptoria tritici, diversity, prevalence, virulence, wheat. &nbsp

Painlevé III′ and the Hankel determinant generated by a singularly perturbed Gaussian weight

In this paper, we study the Hankel determinant generated by a singularly perturbed Gaussian weightw(x,t)=e−x2−tx2,x∈(−∞,∞),t>0. By using the ladder operator approach associated with the orthogonal polynomials, we show that the logarithmic derivative of the Hankel determinant satisfies both a non-linear second order difference equation and a non-linear second order differential equation. The Hankel determinant also admits an integral representation involving a Painlevé III′. Furthermore, we consider the asymptotics of the Hankel determinant under a double scaling, i.e. n→∞ and t→0 such that s=(2n+1)t is fixed. The asymptotic expansions of the scaled Hankel determinant for large s and small s are established, from which Dyson's constant appears.