GL Model Research Articles

Photothermal effects induced by laser radiation in a 2D axi-symmetric generalized thermoelastic semiconducting half space using MGL model

In this paper, a novel model based on the strain-temperature rate-dependent theory is investigated to study the coupling influences of thermal, elastic, and plasma waves during the photothermal process in a 2D axi-symmetric semiconducting half space. The surface absorption technique is used to illuminate the surface of the medium by a laser beam whose temporal and spatial profiles are Gaussian, moreover, the surface is also considered traction free. Integral transform method is applied using Laplace and Hankel transformations to obtain a general solution to the considered problem. Inverse Laplace transform is obtained computationally using Rimann-Sum approximation. Silicon element is chosen as an application to show the compatibility of the results of the MGL model with GL and CTE models, moreover the relaxation times effects of the new model were studied.

Evaluation of cloud-type impact on performance of the GL model version 1.2 for estimation of solar irradiance

ABSTRACT This work evaluates the quality of the satellite-based GLobal radiation model version 1.2 (GL1.2) estimates for four cloud classes. The GL1.2 calculates the global solar irradiance at ground level using images from a single visible band channel (VIS) of the Geostationary Operational Environmental Satellite – GOES (GOES-East). The model´s performance was assessed by comparing hourly mean GL1.2 values with ground-based hourly measurements from the Brazilian National Institute of Meteorology (INMET, 354 automatic weather stations), for the entire year 2017. A satellite-based cloud classifier was adopted to discriminate the datasets according to prevailing cloud conditions (cumulus, stratus, cirrus and multilayer), but the clear sky behaviour was presented. The results were analysed for the five Brazilian regions. In the first analysis, we selected days with a predominance for five stations. It was found that the diurnal cycle was well reproduced. Then the regional investigation for the cloud types reveals that the best results are found for the Center West region over multilayer cloud (mean bias error, MBEannual = -2 ± 91 Wm−2 and root mean squared error, RMSE = 91 Wm−2), while the worst ones are in the North over cumulus fields (MBEannual = 101.5 ± 136.4 Wm−2). When considering all cloud types, the MBEannual is lower than 5 Wm−2 for the Northeast, Southeast and South regions, but it reaches 101 Wm−2 in the North. It is noteworthy that winter has the highest MBE in all classes analysed in the North, as well as cirrus situations in other regions. Although the inhomogeneities of cumulus and the semitransparent cirrus clouds tend to propagate errors to the model, the quality of GL1.2 data has a high degree of agreement with the observations. Improvements including an updated monthly minimum reflectance (R min) and water vapour column (H2Ovapour), and a better spatial resolution of the Advanced Baseline Imager (ABI) of GOES-16 (ABI/GOES-16) VIS imagery will allow refinement, especially for cumulus clouds.

Ginzburg Landau Model for Nanofluid Convection in the Presence of Time Periodic Plate Modulation

Here we study thermal modulation effect on nanofluid convection and discuss heat and mass transfer in the layer. The non-uniform time periodic boundary conditions of the system are considered. A weak non-linear stability analysis has been performed and obtained heat and mass transfer coefficients as a function of the system parameters. The Ginzburg Landau model was employed to derive nanofluid convective amplitude at different stages of flow disturbances and modulation. Slow variations of time scale shows that thermal modulation impact on transport phenomenon for the case of out phase modulation (OPM) and (lower boundary modulation) LBM. Also the effect of IPM (in-phase modulation) is observed low effect on Nu and which are similar to un-modulation case. It is also justified that LBM restuls are similar to gravity modulation results. It is found that thermal modulation and concentration Rayleigh numbers are either stabilize or destabilize the system. Further, GL model shows better results on regulation of transport process

Yang-Baxter deformation of WZW model based on Lie supergroups: The cases of GL(1|1) and (C3 + A)

We proceed to generalize the Yang-Baxter (YB) deformation of Wess-Zumino-Witten (WZW) model to the Lie supergroups case. This generalization enables us to utilize various kinds of solutions of the (modified) graded classical Yang-Baxter equation ((m)GCYBE) to classify the YB deformations of WZW models based on the Lie supergroups. We obtain the inequivalent solutions (classical r-matrices) of the (m)GCYBE for the gl(1|1) and (C3+A) Lie superalgebras in the non-standard basis, in such a way that the corresponding automorphism transformations are employed. Then, the YB deformations of the WZW models based on the GL(1|1) and (C3+A) Lie supergroups are specified by skew-supersymmetric classical r-matrices satisfying (m)GCYBE. In some cases for both families of deformed models, the metrics remain invariant under the deformation, while the components of B-fields are changed. After checking the conformal invariance of the models up to one-loop order, it is concluded that the GL(1|1) and (C3+A) WZW models are conformal theories within the classes of the YB deformations preserving the conformal invariance. However, our results are interesting in themselves, but at a constructive level, may prompt many new insights into (generalized) supergravity solutions.

Combining Spatiotemporally Global and Local Interpolations Improves Modeling of Annual Land Surface Temperature Cycles

Annual temperature cycle (ATC) models are widely used to characterize temporally continuous land surface temperature (LST) dynamics within an annual cycle. However, the existing ATC models ignore the spatiotemporally local correlations among adjacent LST pixels and are inadequate for capturing the complex relationships between LSTs and LST-related descriptors. To address these issues, we propose an improved ATC model (termed the ATC_GL), which combines both the spatiotemporally global and local interpolations. Using the random forest (RF) algorithm, the ATC_GL model quantifies the complex relationships between LSTs and LST-related descriptors such as the surface air temperature, normalized difference vegetation index, and digital elevation model. The performances of the ATC_GL and several extensively used LST reconstruction methods were compared under both clear-sky and overcast conditions. In the scenario with randomly missing LSTs, the accuracy of the ATC_GL was 2.3 K and 3.1 K higher than that of the ATCE (the enhanced ATC model) and the ATCO (the original ATC model), respectively. In the scenario with LST gaps of various sizes, the ATC_GL maintained the highest accuracy and was less sensitive to gap size when compared with the ATCH (the hybrid ATC model), Kriging interpolation, RSDAST (Remotely Sensed Daily Land Surface Temperature), and HIT (Hybrid Interpolation Technique). In the scenario of overcast conditions, the accuracy of the ATC_GL was 1.0 K higher than that of other LST reconstruction methods. The ATC_GL enriches the ATC model family and provides enhanced performance for generating spatiotemporally seamless LST products with high accuracy.

A GL photo-thermal theory upon new hyperbolic two-temperatures in a semiconductor material

A novel GL model of a new hyperbolic two-temperatures theory is studied to investigate the propagation of the thermoelastic waves on semiconductor materials. The basic equations are studied during the photo-excitation processes in the context of the photo-thermo-elastic model. The outer surface of the semiconductor medium is illuminated by a laser pulse. By using Laplace transform with the eigenvalues scheme, the analytical solutions of all studying fields are presented. The carrier density variation, the variations of the thermodynamic and the conductive temperatures, the displacement and stress components in a semi-infinite semi-conductor material are estimated. The effects of the hyperbolic two-temperature parameter and the relaxation times on the distributions of wave propagation of physical fields for semiconductor silicon (Si) medium are shown graphically and discussed.

An Interdisciplinary Study of Cybersecurity Investment in the Nonprofit Sector

Cybersecurity is becoming a worldwide priority. It is critical for organizations to quantify losses from cybercrimes and make informed decisions on cybersecurity investments. This paper expands the body of knowledge in cybersecurity of nonprofit organizations (NPOs)—a less-researched area—by examining investment in NPOs’ cybersecurity from the business and economics perspectives. The authors combine two economics and risk management models to quantify the potential loss caused by a cyberattack. The paper provides a hypothetical example of applying the insights from the GL and FAIR risk models to assess the information assets of an NPO and calculating the optimal level of cybersecurity investment. Developing cybersecurity measures for NPOs is equally important as developing cybersecurity strategies, tools, and policies for large corporations or small businesses. Therefore, the findings of this paper can serve as decision-making tools for NPOs to evaluate information security assets, estimate the potential loss caused by cyberattacks, and determine the optimal investment value in cybersecurity measures.

Study of High-spin States for 90,91,92Y Isotopes by Using Oxbash Code

Abstract: In this paper, calculations of 90,91,92Y isotopes have been performed by application of nuclear shell model in the Gloeckner (Gl) model space for two different interactions (Gloeckner (Gl) and Gloeckner pulse bare G-Matrix (Glb) using Oxbash code. The energy levels are compared and discussed with experimental data and based on our results, many predictions about spins and parity were observed between experimental states, in addition to the predictions of low-energy spectra and B (E2; ↓) and B (M1; ↓)) transitional strengths in the isotopes 90,91,92Y. These predictions were not known in the experimental data. Keywords: Energy levels, Transition probabilities, Oxbash code.

Determining a realistic ranking of the most dangerous process equipment of the ammonia production process: A practical approach

OCI Nitrogen seeks to gain knowledge of (leading) indicators regarding the process safety performance of their ammonia production process. The current research determines the most dangerous process equipment by calculating their effects resulting from a loss of containment using DNV GL's Phast™ dispersion model. In this paper, flammable and toxic effects from a release from the main equipment of an ammonia plant have been calculated. Such an encompassing approach, which can be carried out for an entire plant, is innovative and has never been conducted before. By using this model, it has been demonstrated that the effects arising from an event of failure are the largest in process equipment containing pressurized synthesis gas and ‘warm’ liquid ammonia, meaning the ammonia buffer tanks, ammonia product pumps, and the ammonia separator. Most importantly, this document substantiates that it is possible to rank the most hazardous process equipment of the ammonia production process based on an adverse impact on humans using the calculated effect distance as a starting point for a chance of death of at least 95%. The results from the effect calculations can be used for risk mapping of an entire chemical plant or be employed and applied in a layer of protection analysis (LOPA) to establish risk mitigation measures.

Revisiting Reynolds and Nusselt numbers in turbulent thermal convection

In this paper, we extend Grossmann and Lohse’s (GL) model [S. Grossmann and D. Lohse, “Thermal convection for large Prandtl numbers,” Phys. Rev. Lett. 86, 3316 (2001)] for the predictions of Reynolds number (Re) and Nusselt number (Nu) in turbulent Rayleigh–Bénard convection. Toward this objective, we use functional forms for the prefactors of the dissipation rates in the bulk and boundary layers. The functional forms arise due to inhibition of nonlinear interactions in the presence of walls and buoyancy compared to free turbulence, along with a deviation of the viscous boundary layer profile from Prandtl–Blasius theory. We perform 60 numerical runs on a three-dimensional unit box for a range of Rayleigh numbers (Ra) and Prandtl numbers (Pr) and determine the aforementioned functional forms using machine learning. The revised predictions are in better agreement with the past numerical and experimental results than those of the GL model, especially for extreme Prandtl numbers.

New constraint of an attractor GL model in braneworld context

We are interested in studying the generalization of the first chaotic inflation model in supergravity, which was proposed by Goncharov and Linde (GL model) and was recently revisited, in the framework of the Randall–Sundrum type 2 braneworld model. This model predicts a tiny ratio [Formula: see text] and [Formula: see text]. Our scenario predicts a great tensor-to-scalar ratio [Formula: see text] of the order [Formula: see text] and the central value of the scalar spectral index [Formula: see text] for a particular choice of values of brane tension [Formula: see text] and the parameter [Formula: see text]. We have shown that this scenario reproduces successfully an attractor behavior. We have also derived all known spectrum inflationary parameters, in particular the running [Formula: see text] and the power spectrum of the curvature perturbations [Formula: see text] which are widely consistent with Planck observations.

Reflection and refraction of magneto-thermoelastic plane wave at the pre-stressed liquid-solid interface in generalized thermoelasticity under three theories

The thermomagnetic effect on plane wave propagation at the liquid-solid interface with nonclassical thermoelasticity is investigated. It is assumed that liquid-solid half-space is under initial stress. Numerical computations are performed for the developed amplitude ratios of P, SV and thermal waves under Cattaneo-Lord-Shulman theory, Green-Lindsay theory and classical thermoelasticity. The system of developed equations is solved by the application of the MATLAB software at different angles of incidence for Green and Lindsay model. The effect of initial stress and magnetic field in the lower half-space are discussed and comparison is made in LS, GL and CT models of thermoelasticity. In the absence of magnetic field, the obtained results are in agreement with the same results obtained by the relevant authors. This study would be useful for magneto-thermoelastic acoustic device field.

Transient responses of bi-layered structure based on generalized thermoelasticity: Interfacial conditions

Multi-layered structures are always designed to apply in the harsh environment, e.g. high temperatures and impact loads, etc. In this work, thermoelastic analysis of a bi-layered structure is implemented in the context of generalized thermoelasticity, e.g. GL model. To distinguish from existed works, the thermal contact resistance and the elastic wave impendence at the interface are considered. Accordingly, they may degenerate into the continuous conditions by selecting ideal parameters. In the numerical part, a semi-analytical solution is obtained by using the Laplace transform method, upon which the effects of the thermal contact resistance, elastic wave impendence ratio, thermal conductivity ratio and heat capacity ratio on the responses are studied. And finally, some concluding remarks are summarized, based upon which the structure may be optimized by adopting suitable material ratio in both thermal and elastic sense.

Robust Gradient Learning With Applications.

This paper addresses the robust gradient learning (RGL) problem. Gradient learning models aim at learning the gradient vector of some target functions in supervised learning problems, which can be further used to applications, such as variable selection, coordinate covariance estimation, and supervised dimension reduction. However, existing GL models are not robust to outliers or heavy-tailed noise. This paper provides an RGL framework to address this problem in both regression and classification. This is achieved by introducing a robust regression loss function and proposing a robust classification loss. Moreover, our RGL algorithm works in an instance-based kernelized dictionary instead of some fixed reproducing kernel Hilbert space, which may provide more flexibility. To solve the proposed nonconvex model, a simple computational algorithm based on gradient descent is provided and the convergence of the proposed method is also analyzed. We then apply the proposed RGL model to applications, such as nonlinear variable selection and coordinate covariance estimation. The efficiency of our proposed model is verified on both synthetic and real data sets.

Single-field α-attractors

I describe a simple class of α-attractors, generalizing the single-field GL model of inflation in supergravity. The new class of models is defined for 0<α ≲ 1, providing a good match to the present cosmological data. I also present a generalized version of these models which can describe not only inflation but also dark energy and supersymmetry breaking.

Laser-light backscattering imaging for early decay detection in citrus fruit using both a statistical and a physical model

The early detection of decay caused by fungi in citrus fruit is a primary concern in the post-harvest phase, the automation of this task still being a challenge. This work reports new progress in the automatic detection of early symptoms of decay in citrus fruit after infection with the pathogen Penicillium digitatum using laser-light backscattering imaging. Backscattering images of sound and decaying parts of the surface of oranges cv. ‘Valencia late’ were obtained using laser diode modules emitting at five wavelengths in the visible and near-infrared regions. The images of backscattered light captured by a camera had radial symmetry with respect to the incident point of the laser beam, these being reduced to a one-dimensional profile through radial averaging. Two models were used to characterise backscattering profiles: a statistical model using the Gaussian–Lorentzian cross product (GL) distribution function with five parameters and a physical approach calculating the absorption, μa, and reduced scattering, μs′, coefficients from Farrell’s diffusion theory. Models described radial profiles accurately, with slightly better curve-fitting results (R2⩾0.996) for the GL model compared to Farrell’s model (R2⩾0.982), both indicating significant differences in the parameters between sound and decaying orange skin at the five wavelengths. For dimensionality reduction purposes, feature selection methods were employed to select the most relevant backscattering profile parameters for the detection of early decay lesions. The feature vectors obtained were used to discriminate between sound and decaying skin using a supervised classifier based on linear discriminant analysis. The best classification results were achieved using a reduced set of GL parameters, yielding a maximum overall classification accuracy of 93.4%, with a percentage of well-classified sound and decaying samples of 92.5% and 94.3%, respectively. Results also pointed out application limits of Farrell’s diffusion theory at 532nm laser wavelength, for which high absorption of pigments occurred.

Green Lindsay model on reflection and refraction of p- and SV-waves at interface between solid-liquid media presence in magnetic field and initial stress

In this paper, the reflection and transmission of thermoelastic wave at a solid-liquid interface in presence of initial stress and magnetic field is investigated in context of GL model. After solving the governing equations, we can find the two reflection and refraction coefficients of incident p-(pressure) and SV- (shear vertical) waves in presence of initial stress and magnetic field. The boundary conditions at the interface that: (i) displacement continuity, (ii) vanishing the tangential displacement, (iii) continuity of normal force per unit initial area, (iv) tangential force per unit initial area must vanish, and (v) continuity of temperature is applied. The appropriate expressions to find the amplitude ratios for the two incidence waves (p- and SV-waves) have been obtained. A numerical example is considered for the reflection and transmitted coefficients of the incident waves, in which we study the effect of initial stresses and magnetic field. The results obtained are presented graphically for the effect of magnetic field and initial stress to display the phenomena physical meaning.

Three-dimensional fractional-spin gravity

Abstract Using Wigner-deformed Heisenberg oscillators, we construct 3D Chern-Simons models consisting of fractional-spin fields coupled to higher-spin gravity and internal nonabelian gauge fields. The gauge algebras consist of Lorentz-tensorial Blencowe-Vasiliev higher-spin algebras and compact internal algebras intertwined by infinite-dimensional generators in lowest-weight representations of the Lorentz algebra with fractional spin. In integer or half-integer non-unitary cases, there exist truncations to gl(ℓ, ℓ ± 1) or gl(ℓ|ℓ ± 1) models. In all non-unitary cases, the internal gauge fields can be set to zero. At the semi-classical level, the fractional-spin fields are either Grassmann even or odd. The action requires the enveloping-algebra representation of the deformed oscillators, while their Fock-space representation suffices on-shell.The project was funded in part by F.R.S.-FNRS “Ulysse” Incentive Grant for Mobility in Scientific Research.

Anisotropic Magnetic Fluctuations and Superconductivity in Ferromagnetic Superconductor UCoGe

We have performed 59Co NQR / NMR measurements on the single-crystalline UCoGe, in order to investigate the relationship between ferromagnetism and superconductivity. The measurements of Knight-shift and nuclear spin-lattice relaxation rate provide clear evidence that both static and dynamic susceptibilities are ferromagnetic with Ising anisotropy. In addition, Hc2 also shows extremely large anisotropy which can not be explained by the GL model with anisotropy of effective mass. These data suggest intimate relationship between Ising magnetization and anisotropic superconductivity in UCoGe.

TEMPERATURE RATE DEPENDENT GENERALIZED THERMOELASTICITY WITH MODIFIED OHM'S LAW

The present work is concerned with an electro-magneto-thermoelastic coupled problem for a homogeneous, isotropic, thermally and electrically conducting semi-infinite solid medium in two-dimensional space where an initial magnetic field with constant intensity acts parallel to the plane boundary of the half-space. The surface of the half-space taking as traction free which is subjected to a thermal shock. The modified Ohm's law including the temperature gradient and charge density effect to the governing equations of the generalized thermoelasticity under the temperature rate dependent thermoelasticity (TRDTE) proposed by Green and Lindsay (GL model) has been introduced. Normal mode analysis together with eigenvalue approach technique is used to obtain the general solutions for the physical quantities. Numerical results for the physical quantities are illustrated graphically and analyzed. The graphical results indicate that the effect of the coefficient connecting the temperature gradient and the electric current density of the modified Ohm's law on the plane waves is very pronounced. Comparison are made with the results obtained in the absence of the above coefficient.