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Background One of the first clinical observations of ibrutinib activity in the treatment of chronic lymphocytic leukemia (CLL) is a rapid decline in lymph nodes size. This phenomenon is accompanied by an hyperlymphocytosis, either transient or prolonged, which is associated with distinct clinical responses and thus has an impact on long-term outcomes. Understanding which factors determine distinct disease courses upon ibrutinib treatment remains a scientific challenge. Methods and findings From 2016 to 2021, we conducted a longitudinal and observational study in 2 cohorts of patients with chronic lymphocytic leukemia (CLL) (cohort 1, n = 41; cohort 2, n = 81). These cohorts reflect the well-known clinical features of CLL patients, such as Male/Female sex ratio of 2/1, a median age of 70 years at diagnosis, and include patients in first-line therapy (27%) or relapsed/refractory patients (73%). Blood cell counts were followed for each patient during 2 years of ibrutinib treatment. In addition, immunophenotyping and whole-body magnetic resonance imaging (MRI) were assessed in patients from cohort 1. These data were integrated in a newly built mathematical model, inspired by previous mathematical works on CLL treatment and combining dynamical and statistical models, leading to the identification of biological mechanisms associated with the 2 types of clinical responses. This multidisciplinary approach allowed to identify baseline parameters that dictated lymphocytes kinetics upon ibrutinib treatment. Indeed, ibrutinib-induced lymphocytosis defined 2 CLL patient subgroups, transient hyperlymphocytosis (tHL) or prolonged hyperlymphocytosis (pHL), that can be discriminated, before the treatment, by absolute counts of CD4.sup.+ T lymphocytes (p = 0.026) and regulatory CD4 T cells (p = 0.007), programmed cell death protein 1 PD1 (p = 0.022) and CD69 (p = 0.03) expression on B leukemic cells, CD19/CD5.sup.high /CXCR4.sup.low level (p = 0.04), and lymph node cellularity. We also pinpointed that the group of patients identified by the transient hyperlymphocytosis has lower duration response and a poor clinical outcome. The mathematical approach led to the reproduction of patient-specific dynamics and the estimation of associated patient-specific biological parameters, and highlighted that the differences between the 2 groups were mainly due to the production of leukemic B cells in lymph node compartments, and to a lesser extent to T lymphocytes and leukemic B cell egress into bloodstream. Access to additional data, especially longitudinal MRI data, could strengthen the conclusions regarding leukemic B cell dynamics in lymph nodes and the relevance of 2 distinct groups of patients. Conclusions Altogether, our multidisciplinary study provides a better understanding of ibrutinib response and highlights new pharmacodynamic parameters before and along ibrutinib treatment. Since our results highlight a reduced duration response and outcome in patients with transient hyperlymphocytosis, our approach provides support for managing ibrutinib therapy after 3 months of treatment. Trial registration ClinicalTrials.gov NCT02824159., Author(s): Sarah Cadot 1,2, Chloe Audebert 3,4, Charlotte Dion 5, Soleakhena Ken 1,6, Loic Dupré 7,8, Laetitia Largeaud 1,9, Camille Laurent 1,2,9, Loic Ysebaert 1,2,9, Fabien Crauste 10, Anne Quillet-Mary [...]

Forecasting the time development of scour depth at bridge pier foundations is of great significance to mitigate or avoid the potential failure of bridges. Presently, several models have been developed to predict the scour depth at the base of bridge piers in the case of flood events. This study summarizes existing models for the temporal evolution of bridge pier scour and divides these studies into semiempirical models and empirical models, as well as artificial intelligence models. Several experimental data sets collected from previous studies, 665 points in total, are used to develop a new multigene genetic programming (MGGP) model for temporal scour depth at a circular bridge pier. In addition, independent data, 899 points in total, from previous studies and new physical modeling tests are applied to evaluate the behaviours of existing models, as well as the newly developed MGGP model. It is shown that the MGGP model has good prediction capability when compared with existing empirical and mathematical models. Key words: scour, bridge piers, time-dependent, multigene genetic programming, Introduction The removal of bed material around bridge piers caused by water flow is described as scouring. Scour at bridge piers could significantly lead to bridge failure, especially during flood [...]

This study developed an in-mold induction heating system for the injection compression molding process to overcome the problem of incomplete filling of microstructures caused by the formation of skin layers and residual stress caused by flow. Moldex3D software was used with the Taguchi method to optimize the molding parameters for both injection molding and injection compression molding, with the aim of reducing warpage and improving optical quality. The in-mold induction heating system has extremely high heating efficiency. Experiments revealed that a time of only 8 s was required to inducted-heat up the core to the glass transition temperature which keeps the melt under a good state of flow and allows a replication rate of 97%. In addition, the ICM process can effectively reduce the flow-induced residual stress and improve the optical properties of the obtained samples. Finally, the illuminance of the product fabricated through ICM with induction heating for 10 s was 2.3 times higher than that of the product obtained through ICM without induction heating. Accordingly, the proposed induction heating system is feasible for use in ICM the rapid manufacturing of high-quality optical products with microstructures. KEYWORDS induction heating, injection compression molding, microstructure, optical property, residual stress, Taguchi method, 1 | INTRODUCTION Injection molding (IM) has been extensively used to fabricate various high-precision products. Conventional IM techniques have been used for the mass production and the fabrication of products [...]

Based on the time-temperature equivalence principle, the relationship between the melt relaxation time (MRT) and melt heating temperature (MHT) in an improved gas-assisted extrusion (GAE) of a polypropylene (PP) sheet was investigated by numerical simulations. In the simulations, the MRT was varied and the inherent properties of the MHT were controlled using experimental methods. With an increase in MRT, the velocity in all directions, pressure drop, and shear rate of the melt increased; however, increasing the MRT does not always yield a positive effect on the GAE process of the melt. For instance, the melt velocity increased vertically at the die exit with MRT, resulting in an outward extrudate swell. In addition, the extruded product was intact when the melt was heated to 220[degrees] C, which verified the principle of time-temperature equivalence. KEYWORDS gas-assisted extrusion, heating temperature, plastic sheets, relaxation time, timetemperature equivalence principle, 1 | INTRODUCTION In conventional plastic sheet extrusion, the high viscoelasticity of polymers makes them susceptible to undesirable extrudate swell [1-3] and tensile deformation, [4-9] and the internal stress in [...]

In this article, the finite element analysis (FEA) combined with the fracture mechanism of rubber was used to predict the fatigue life of the radial tire carcass rubber. Five tire structures with different angles were designed under the premise of ensuring the same height of carcass cord and radius of curvature. The fatigue life prediction of tires was performed using the Lake-Lindley model in combination with finite element models and crack extension tests. The location and causes of damage in 11.00R20 load radial tires were analyzed, and the effect of sleeve cord angle on tire mechanical properties and fatigue performance was investigated to predict the fatigue life of the radial tire carcass rubber. The simulation test results are within 10% error when compared with the actual durability test results, which can fully meet the daily design development of tire enterprises. The fatigue life prediction method can shorten the development cycle and reduce the development cost of tires. Improving tire durability is important for reducing the use of petrochemical materials and environmental pollution. KEYWORDS carcass cord, crack extension experiment, fatigue life, finite element analysis, tire design, 1 | INTRODUCTION With the rapid development of the economy, the demand for transportation is gradually increasing. Road transport has been moving towards heavy-duty, high-speed, and efficient. The tire is [...]

Extraterrestrial life is a genuine scientific possibility. Earth proves that at least one habitable planet, even a planet with technological intelligence, can exist. Astronomers have discovered more than 5,000 exoplanets--worlds [...]

The behaviour of partially grouted (PG) masonry shear walls is complex due to masonry's anisotropic nature and the nonlinear interactions among its constituents. Currently available code- and research-based shear strength equations provide highly variable results when predicting the in-plane shear strength of PG masonry walls. It is crucial to develop a greater understanding in this area, as sudden shear failures of masonry walls can lead to catastrophic losses of human life and property. This study presents the development of several new in-plane shear strength models for PG masonry walls using stepwise regression and model trees with data compiled from 292 experimentally tested walls. The models are found to significantly outperform existing code- and research-based shear strength equations. It was found that, of the variables studied, the most significant ones are the axial load, wall geometry, compressive strength of mortar, and area of interior vertical reinforcement. Key words: partially grouted, masonry wall, prediction models, shear strength, stepwise regression, model trees, 1. Introduction The behaviour of masonry shear walls is complex due to the interactions between concrete blocks, mortar, grout, and horizontal and vertical reinforcing steel (Hung 2018). Partially grouted (PG) [...]

In this paper, we study the generalized Klein-Gordon oscillator under the effects of the violation of Lorentz symmetry defined by a tensor field [([K.sub.F]).sub.[mu]v[alpha][beta]] out of the standard model extension. We consider a possible scenario of Lorentz-violating with a Cornell-type potential form electric field and a linear magnetic field that contributes a harmonic-type central potential effects in the quantum motions of oscillator fields. The bound-state solutions of the wave equation using the parametric Nikiforov-Uvarov method by considering Coulomb- and Cornell-type potential form functions are obtained. We see that the eigenvalue solutions get modified by the Lorentz symmetry breaking effects in comparison to the Landau levels (without Lorentz- violation effects in flat space). Key words: Lorentz symmetry violation, relativistic wave equations, Nikiforov-Uvarov method, solutions of wave equations: bound-states, 1. Introduction The standard model extension (SME) in high energy physics is an effective field theory that incorporates known physics and Lorentz-violating terms [1-5]. The violations enter through Lorentz non-invariant [...]

In this article, we study the effects of minimal length corrections on the cyclotron acceleration and radiation of a charged particle moving in a magnetic monopole field. Using the modified Hamiltonian describing the dynamics of a charged particle moving in a magnetic monopole field, we derive the modified cyclotron frequency and modified acceleration. Also, we derive the modified power for the cyclotron radiation using the modified acceleration. We find that all modified quantities are dependent on the deformation parameter a. In addition, we find that the modified electromagnetic angular momentum and magnetic charges are not quantized as an integer multiple; thus, we establish that the modified Dirac quantization condition and the usual Dirac quantization condition is just the term of zero order in a. The modified Dirac quantization condition allows fractional charges that arise from vacuum fluctuations. In the Born approximation, we derive the modified scattering cross-section and then we estimate the upper bound on the minimal length. Key words: quantum gravity, minimal length, cyclotron acceleration, magnetic monopole, Dirac quantization, 1. Introduction The existence of magnetic monopoles was predicted by Paul Dirac as a necessary condition for the quantization of electric charges [1, 2]. But no magnetic charges have been [...]

We investigate the Dirac and Klein-Gordon equations, as well as greybody radiation, for the Hayward black hole (BH) space-time. We first consider the Dirac equation using a null tetrad in the Newman-Penrose formalism. The equations are then separated into angular and radial parts. A pair of one-dimensional Schrodinger-like wave equations with effective potentials is obtained from the radial part. In order to examine the behavior of potentials, they are plotted with respect to radial distances. Additionally, the Klein-Gordon equation is considered in the Hayward BH space-time. At the end, we compute greybody factors for bosons and fermions and our results are shown graphically and discussed. Key words: Hayward black hole, Dirac equation, Klein-Gorden equations, greybody factors, radiation, 1. Introduction Regular black holes (BHs) were discovered first by Bardeen and came to be known as Bardeen BHs [1-3]. These types of BHs do have an event horizon but [...]

Antimicrobial resistance (AMR) is a leading threat to global health (1). An estimated 4.95 million deaths were associated with bacterial AMR in 2019 worldwide (2), mostly caused by 6 pathogens: [...]

Space-charge effects are familiar to students of solid state physics, semiconductor devices, and surface science. They are usually estimated under the strong depletion or space-charge layer approximation (SCLA), whose limitations are rarely fully discussed. A formal description of these effects is presented, followed by numerical solutions to a one- dimensional Poisson's equation. This equation is valid in cases of charge depletion and of mild accumulation near surfaces and interfaces. Poisson's equation as it applies to a film/substrate interface is analyzed to obtain the boundary condition for the potential at the metallurgical junction. A practical applied example discusses the impact of depletion effects on the determination of the charge carrier concentration by Hall effect measurement in homoepitaxial semiconductor thin films. Examples are highlighted where the SCLA is not an accurate approximation. Key words: depletion effects, Poisson's equation, space-charge, Hall effect, 1. Introduction The effects of charge screening in semiconductors have been studied for decades. They are well known and described in textbooks and the specialized literature. However, despite the excellent [...]

In this study, we examined the horizon problem in the Bianchi type-V cosmological model. Our investigation showed that we could not obtain the solution to the horizon problem without neglecting the strong energy condition. As a result, we have shown no horizon problem in our model with figures and calculations. Key words: horizon problem, cosmology, Bianchi type V, homogeneous and anisotropic universe model, general relativity, 1. Introduction Edwin Hubble's observations in 1920 show that our observed universe gets further away from each other with acceleration in proportion to the interval between them, which means that [...]

Case investigation and contact tracing (CICT) was a pillar among COVID-19 prevention strategies, especially before vaccine availability (1,2). However, standard CICT relies on staff to reach cases and close contacts, [...]

The evolution of the dark energy within the scope of a spatially homogeneous and isotropic Friedmann-Robertson-Walker model filled with barotropic fluid and dark energy is examined. We have considered the two cases of an interacting and non-interacting two-fluid (barotropic and dark energy) scenario and obtained the exact solutions to the corresponding field equations. In an interacting model, we have considered linear as well as quadratic interaction between dark sectors of the universe. We have also given the quadrature form for general interaction coupling parameter via Q = [alpha] [[rho].sub.m.sup.n], n [greater than or equal to] 1 and discussed the evolution of energy densities and effective equation of state with cosmic time for flat, closed, and open universes. It is also examined that the matter energy density is dominated in early phase of the universe, whereas the dark energy density is dominated in later phase of the universe for both scenarios, which is in concurrence with current observations. Key words: cosmological model, dark energy, coupling parameter, 1. Introduction Observations of distant supernovae (SNe Ia) [1-5], fluctuation of cosmic microwave background radiation (CMBR) [6,7], the large-scale structure [8, 9], Sloan Digital Sky Survey [10, 11], Wilkinson Microwave [...]

This work discusses the responsible quantities of the emergence inhomogeneity by taking locally anisotropic radiating fluid in f (G, T) theory, where T and G indicate the trace of stress energy tensor and Gauss-Bonnet terms. The temporal and radial change in mass function is observed with the help of a modified version of Einstein's field equations. To observe the dynamics of self-gravitating fluid, the dynamical equations and differential equations for conformal tensor are constructed, which help to understand the role of correction terms, Weyl curvature, and fluid parameter in the energy-density irregularity. Various forms of fluid are addressed to meet the desired results. Key words: f (G, T) gravity, radiating fluid, Weyl curvature, energy-density irregularity, 1. Introduction Dynamical relationships between space and time were discussed in Einstein's general theory of relativity (GR), in which Einstein assumed the universe to be static. His theory lightened up [...]

All models are beautiful--even mathematical ones. They provide insights to scientists and to the general public about a vast array of phenomena in the real world, and we have come [...]

The real-time evaluation of the effectiveness of vaccination campaigns at the population level is essential for public health policy makers and scientists working toward successful mitigation of the COVID-19 pandemic. [...]

Landscape-level studies such as those on forest management planning and carbon accounting rely on large-area growth projections provided by forest growth models. Nowadays, most of these models are individual tree-based models. The detailed input they require and their complexity are a challenge for the integration into a landscape-level study. A possible alternative consists of approximating the complex model through a meta-model. A meta-model mimics the behaviour of the original model, while being simpler in terms of input and computation. In this study, we developed a Bayesian meta-modelling approach that can be used to obtain a simplified growth model from an individual tree-based model. The approach was exemplified through a real-world case study, namely a forest management unit in the province of Quebec, Canada. Using a Markov chain Monte Carlo method, we managed to fit meta-models based on the Chapman-Richards equation or its derivative for the main potential vegetation types. This meta-modelling approach has the advantages of (i) being an effective method of upscaling, (ii) providing simple meta-models suitable for landscape-level studies, and (iii) ensuring a proper error propagation from the original individual tree-based model into the meta-model. Key words: meta-model, Bayesian statistics, Markov chain Monte Carlo, Metropolis-Hastings algorithm, individual tree-based models, upscaling, forest growth models, forest management planning Les etudes au niveau du paysage, telles que celles portant sur la planification de la gestion forestiere et la comptabilisation du carbone, reposent sur des projections de croissance sur de grandes surfaces fournies par des modeles de croissance forestiere. Aujourd'hui, la plupart de ces modeles sont des modeles bases sur des arbres individuels. Les donnees detaillees qu'ils requierent et leur complexite constituent un defi pour leur integration dans une etude au niveau du paysage. Une alternative possible consiste a approximer le modele complexe par un meta-modele. Un meta-modele imite le comportement du modele original, tout en etant plus simple en termes de saisie et de calcul. Dans cette etude, nous avons developpe une approche de meta-modelisation bayesienne qui peut etre utilisee pour obtenir un modele de croissance simplifie a partir d'un modele base sur des arbres individuels. L'approche a ete illustree par une etude de cas reelle, a savoir une unite de gestion forestiere dans la province du Quebec, au Canada. En utilisant une methode de Monte Carlo par chaines de Markov, nous avons reussi a obtenir des meta-modeles bases sur l'equation de Chapman-Richards ou sa derivee pour les principaux types de vegetation potentielle. Cette approche de meta-modelisation presente les avantages suivants : (i) elle constitue une methode efficace de saut d'echelle, (ii) elle fournit des meta-modeles simples adaptes aux etudes a l'echelle du paysage et (iii) elle assure une propagation correcte des erreurs du modele original base sur les arbres individuels vers le meta-modele. [Traduit par la Redaction] Mots-cles: meta-modele, statistiques bayesiennes, Monte Carlo par chaines de Markov, algorithme de Metropolis- Hastings, modeles bases sur des arbres individuels, saut d'echelle, modeles de croissance forestiere, planification de la gestion forestiere, 1. Introduction Landscape-level studies rely on large-area growth projections to assess the sustainability of ecosystem services such as wood supply, carbon sequestration, and water filtering. In this context, growth models [...]

Recently, the total absorption gamma spectroscopy technique was used to determine the Gamow-Teller (GT) distribution of [beta]-decay of [sup.186]Hg. It was concluded that the best description of the measured data was obtained with dominantly prolate components for both parent [sup.186]Hg and daughter [sup.186]Au. Motivated by the recent findings, we investigate the effect of nuclear deformation on the energy distribution of the GT strength of the decay of [sup.186]Hg into [sup.186]Au within the framework of proton-neutron quasiparticle random phase approximation (pn-QRPA) based on the deformed Nilsson potential. To do the needful, we first calculate the energy levels and shape prediction of [sup.186]Hg within the interacting boson model. The computed GT strength distribution satisfied the model-independent Ikeda sum rule 100% (99.98%) for the prolate (oblate) case. Based on the strength distributions, the deformed pn-QRPA model with separable interaction prefers a prolate shape for the ground state of [sup.186]Hg and supports the shape coexistence for this nucleus. Key words: [sup.186]Hg, Gamow-Teller strength, pn-QRPA, IBM-1, deformation Recemment, la technique de spectroscopie gamma par absorption totale a ete utilisee pour determiner la distribution de la desintegration [beta] de type Gamow-Teller (GT) dans le [sup.186]Hg. Une conclusion etait que la meilleure description des donnees etait obtenue avec une forme prolate pour les deux noyaux parents, [sup.186]Hg et sa fille [sup.186]Au. Motives par ces resultats recents, nous examinons l'effet de la deformation nucleaire sur les distributions de GT dans cette meme desintegration dans le cadre pn-QRPA base sur le potentiel deforme de Nilsson. A cette fin, nous calculons d'abord les niveaux d'energie et la prediction de la forme de [sup.186]Hg a l'aide du modele des bosons en interaction (interacting bosons). La distribution calculee de force GT satisfait a 100 % la regle de somme independante de Ikeda pour un noyau prolate et a 99.98 % pour le cas oblong. Sur la base des distributions de force, le modele pn-QRPA avec interaction separable prefere une forme prolate pour le fondamental de [sup.186]Hg et supporte la coexistence de forme pour ce noyau. Mots-cles: [sup.186]Hg, interaction de Gamow-Teller, pn-QRPA, IBM-1, deformation, 1. Introduction Neutron-deficient Mercury (Hg) isotopes have been studied intensively, both experimentally and theoretically, in the last decades. The motivation behind such investigations is to explore the shape coexistence phenomenon, [...]

Predicting and optimizing performance in earthmoving operations is critical, because they are essential to many construction projects. The complexity of modeling earthmoving operations remains challenging, even with several modeling techniques available, including simulation. This paper advances the state-of-the-art of modeling earthmoving operations by introducing a hybrid fuzzy system dynamics-discrete event simulation framework with the capacity to: capture the dynamism of performance in earthmoving operations; capture subjective uncertainty of several factors affecting them; model their sequential nature and resource constraints; and determine actual travel time, in real time, using online navigation systems. Findings from this research confirm the proposed framework (i) extends the application of simulation techniques for modeling construction processes involving dynamic input variables and subjective uncertainty, through its ability to capture the non-probabilistic uncertainty of construction systems, and (ii) when combined with the use of online navigation systems to assess trucks' travel time, improves the accuracy of earthmoving operation models. Key words: construction modeling, hybrid simulation, system dynamics, discrete event simulation, fuzzy logic. Il est essentiel de prevoir et d'optimiser le rendement des operations de terrassement, car elles sont essentielles a de nombreux projets de construction. La complexite de la modelisation des operations de terrassement constitue un defi, meme avec plusieurs techniques de modelisation disponibles, y compris la simulation. Cet article fait progresser l'etat de la technique de modelisation des operations de terrassement en introduisant un cadre de simulation a evenements discrets et de dynamique de systeme flou hybride avec la capacite de : capter le dynamisme du rendement dans les operations de terrassement; saisir l'incertitude subjective de plusieurs facteurs qui les touchent; modeliser leur nature sequentielle et leurs contraintes en matiere de ressources; et determiner le temps de deplacement, en temps reel, a l'aide des systemes de navigation en ligne. Les resultats de cette recherche confirment que le cadre propose (i) etend l'application des techniques de simulation pour la modelisation des processus de construction impliquant des variables d'entree dynamiques et de l'incertitude subjective, grace a sa capacite a saisir l'incertitude non probabiliste des systemes de construction et (ii) lorsqu'il est combine a l'utilisation de systemes de navigation en ligne pour evaluer le temps de deplacement des camions, ameliore la precision des modeles d'operations de terrassement. [Traduit par la Redaction] Mots-cles : modelisation de la construction, simulation hybride, dynamique de systeme, simulation d'evenements discrets, logique floue., 1. Introduction Due to the increasing complexity of construction systems (e.g., construction activities, operations, and projects), numerous managerial techniques have been developed or adapted from other engineering disciplines to model [...]

This study considered numerical applications of smoothed particle hydrodynamics (SPH) to non-Newtonian flow in filled or partially filled conveying elements of twin-screw extruders (TSEs). The algorithms were validated by using a plane Poiseuille flow. Two geometrical configurations with different gap were investigated. A large sound speed was used to prevent particles penetrating the wall boundary of the complex geometry. The velocity field and flow rate of Newtonian flow and non-Newtonian flow (power law) in filled model and partially filled model were analyzed. The distribution of particles in partially filled conveying element in one rotation is introduced. The rheological properties of material take important effect on the flow in fully filled and partially filled cases. For the fully filled cases, the screw-barrel clearance takes important effect on the flow due to the leakage flow reducing the flow rate. For the partially filled case, the clearance affects the non-Newtonian flow by changing the rheological properties of the fluid. The effect of clearance on Newtonian flow is very limited due to no back pressure in the partially filled case. This work prepared a groundwork for the accurate analysis of real extrusion by SPH. KEYWORDS complex geometry, meshfree method, partially filled flow, power law fluid, twin-screw extruder, 1 | INTRODUCTION Corotating, intermeshing twin-screw extruders (TSEs) are used extensively in polymers, food, and pharmaceutical industries because it has a good mixing and self-cleaning property. Flows in TSE often [...]

This paper has been written to achieve two objectives. The first objective is to provide a discussion of the practical limitations of numerical modelling in the field of geomechanical engineering. Too many discussions of numerical methods in geomechanical engineering are centred on the impressive ability of numerical tools to conduct complex and sophisticated analyses with relative ease and efficiency. Practitioners need to have grounded conversations on numerical modelling regarding the reality that geomechanical designs are often data-limited with high degrees of uncertainty. When data limits and uncertainty are overlooked, geomechanical engineers are at risk of introducing unforeseen fatal flaws into engineering design. The second objective is to provide 'how to' guidelines for model calibration using a variety of data types to qualify and quantify ground reaction. Model calibration is truly the only means to reduce numerical uncertainties. Formal training in numerical modelling is often focused on software utilization and computational methods; however, there are few opportunities for formal training on how to calibrate a model for practical engineering applications. This paper provides guidelines for calibration methods and procedures. Key words: numerical modelling, calibration, Canadian Geotechnical Colloquium, rock mechanics, mechanistic modelling, susceptibility modelling. Cet article a ete redige pour atteindre deux objectifs. Premierement, il s'agit de fournir une discussion sur les limites pratiques de la modelisation numerique dans le domaine de l'ingenierie geomecanique. Trop souvent, les discussions sur les methodes numeriques en ingenierie geomecanique sont centrees sur la capacite impressionnante des outils numeriques a mener des analyses complexes et sophistiquees avec une facilite et une efficacite relatives. Les professionnels ont besoin d'avoir des conversations fondees sur la modelisation numerique en tenant compte du fait que les conceptions geomecaniques sont souvent limitees par les donnees et comportent des degres eleves d'incertitude. En negligeant les limites des donnees et l'incertitude, les ingenieurs geomecaniciens risquent d'introduire des defauts fatals imprevus dans la conception technique. Le deuxieme objectif est de fournir des <> pour la calibration des modeles en utilisant une variete de types de donnees pour qualifier et quantifier la reaction du sol. La calibration des modeles est veritablement le seul moyen de reduire les incertitudes numeriques. Les programmes de formation en modelisation numerique sont souvent axes sur l'utilisation des logiciels et les methodes de calcul, mais il existe peu d'opportunites de formation formelle sur la facon de calibrer un modele pour des applications d'ingenierie pratiques. Ce document fournit des lignes directrices pour les methodes et procedures de calibration. [Traduit par la Redaction] Mots-cles : modelisation numerique, etalonnage, Colloque canadien de geotechnique, mecanique des roches, modelisation mecaniste, modelisation de la susceptibilite., Introduction The application of numerical models in geomechanical engineering can be broadly grouped into two categories based on the ultimate objective of the modelling exercise. One objective is to improve [...]

The bender element (BE) test has been widely used for the dynamic characterization of soil specimens at low-shear strain levels. However, the actual behavior of the BE inside a soil specimen remains unknown. Thus, the current ASTM standard does not consider the interference of compressional and shear waves in BE testing, which can lead to significant errors in the evaluation of shear wave velocities. The main objective of this paper is to present a numerical model of the BE system to better understand the response of the BEs inside a soil sample. The model is calibrated, verified, and then used to demonstrate the importance of taking into consideration the interaction between compressional and shear waves for the correct interpretation of BE measurements. The model successfully captured the measured vibrations of the BE in air as well as inside transparent soils. More importantly, the numerical simulations provide a new understating of the significant interactions of P waves and S waves especially in clay soils. Thus, the proposed coupled piezoelectric and solid mechanics model can be used to study the soil-BE interaction so that sound recommendations can be given to improve the interpretation of BE tests in different soils. Key words: bender element test, laser vibrometer, wave propagation, solid mechanics, piezoelectric, finite element method. L'essai par elements piezoceramiques (<>, BE) a ete largement utilise pour la caracterisation dynamique des echantillons de sol a des niveaux de deformation de cisaillement faibles. Cependant, le comportement reel du BE a l'interieur d'une eprouvette de sol reste inconnu. Ainsi, la norme ASTM actuelle ne tient pas compte de l'interference des ondes de compression et de cisaillement dans les essais BE, ce qui peut entrainer des erreurs importantes dans revaluation des vitesses des ondes de cisaillement. L'objectif principal de cet article est de presenter un modele numerique du systeme BE pour mieux comprendre la reponse des BE a l'interieur d'un echantillon de sol. Le modele est calibre, verifie, puis utilise pour demontrer l'importance de prendre en compte l'interaction entre les ondes de compression et de cisaillement pour une interpretation correcte des mesures BE. Le modele a reussi a capturer les vibrations mesurees du BE dans l'air ainsi qu'a l'interieur de sols transparents. Plus important encore, les simulations numeriques permettent de mieux comprendre les interactions significatives entre les ondes P et les ondes S, en particulier dans les sols argileux. Ainsi, le modele couple piezoelectrique et de mecanique solide propose peut etre utilise pour etudier l'interaction sol-BE de sorte que des recommandations judicieuses puissent etre donnees pour ameliorer l'interpretation des essais BE dans differents sols. [Traduit par la Redaction] Mots-cles : essai de l'element piezoceramique, vibrometre laser, propagation des ondes, mecanique des solides, piezoelectrique, methode des elements finis., 1. Introduction The dynamic soil properties play an important role in the design of earthquake-resistant structures and foundations. The bender element (BE) test and resonant column (RC) test are the [...]

In this study, we theoretically scrutinize the effect of the inverse-square interaction on the thermal properties of two electrons trapped in a parabolic GaAs quantum dot. The analytical energy spectrum was used to calculate the thermal properties of the system using the canonical ensemble formalism. It was found that the thermal energy increased with the increase in temperature, while it remained almost constant for sufficiently low temperatures; it was also demonstrated that the inverse-square interaction increased the thermal mean energy. Moreover, the heat capacity increased sharply within a low-temperature window and saturated to the value of 2 [k.sub.B] in the high-temperature limit. As expected, entropy increased linearly with increasing temperature. It was also shown that both entropy and heat capacity decreased rapidly when the confinement strength increased (or the dot size decreased) in the low-temperature limit, regardless of the influence of the interaction between the electrons. We also show that the number of allowed states of the system decreased as the interaction strength increased (Z([lambda] = 0) > Z([lambda] [not equal to] 0)). Finally, the stability of the system was investigated through F-T curves. The three-dimensional surface for the temperature-dependent mean energy and heat capacity was also plotted. It should be noted that, for the thermal mean energy, partition function, and Helmholtz free energy, the normal physical behavior of the two-oscillator system with Fermi statistics is recovered for [lambda] [right arrow] 0. However, heat capacity and entropy show exact two-fermion oscillator system behavior. The most impressive result found in this work is that the inverse-square interaction does not affect the heat capacity and entropy at all despite its noticeable effects on the thermal mean energy. This, in turn, facilitates theoretical studies related to finding the distinctive parameters of quantum dots without going into the heavy calculations resulting from the effects of interactions. Key words: quantum dot, inverse-square interaction, heat capacity, Helmholtz free energy, entropy. Nous completons une etude theorique de l'effet de l'interaction en carre inverse sur les proprietes thermiques de deux electrons captifs dans un point quantique parabolique GaAs. Le spectre analytique en energie est utilise pour calculer les proprietes thermiques de ce systeme en utilisant le formalisme de l'ensemble canonique. Nous trouvons que l'energie thermique augmente avec la temperature, mais demeure pratiquement constante aux temperatures suffisamment basses. Nous demontrons aussi que l'interaction en carre inverse augmente l'energie thermique moyenne. De plus, la capacite calorifique augmente rapidement a l'interieur d'une fenetre a basse temperature et elle sature a la valeur 2[k.sub.B] dans la limite des hautes temperatures. Comme attendu, l'entropie augmente lineairement avec la temperature. Nous montrons egalement que l'entropie et la capacite calorifique diminuent rapidement lorsque la force de confinement augmente (le point quantique se contracte) dans la limite des basses temperatures et ce, sans regard a l'influence de l'interaction entre les electrons. Nous montrons aussi que le nombre des etats permis du systeme diminue lorsque la force d'interaction augmente (Z([lambda] = 0) > Z([lambda] [not equal to] 0)). Finalement, nous etudions la stabilite du systeme a l'aide des courbes F-T. Nous tracons des courbes de la surface tridimensionnelle pour la dependance en temperature de l'energie moyenne et de la capacite calorifique. Il faut souligner que, pour l'energie thermique moyenne, la fonction de partition et l'energie libre de Helmholtz, nous recouvrons le comportement physique normal d'un systeme a deux oscillateurs obeissant a la statistique de Fermi dans la limite ou [lambda] [right arrow] 0. Cependant, pour la capacite calorifique et l'entropie, le comportement est alors celui d'un oscillateur a deux fermions. Le resultat le plus impressionnant ici, c'est que l'interaction en carre inverse n'affecte en aucune facon la capacite calorifique ni l'entropie, malgre un effet tres notable sur l'energie thermique moyenne. En retour, ceci facilite les etudes theoriques reliees a la decouverte de parametres distinctifs de points quantiques, sans aller dans des calculs lourds resultant des effets de l'interaction. [Traduit par la Redaction] Mots-cles: point quantique, interaction en carre inverse, capacite calorifique, energie libre d'Helmholtz, entropie., 1. Introduction In the last decade, researchers have been extensively interested in nanotechnology in all its theoretical and experimental branches because of its ability to create a wide range of [...]

The spectral parameters (energy levels, wavelengths, transition probabilities, line strengths, and oscillator strengths) of resonance lines for Ba VIII, La IX, and Ce X have been obtained using the multiconfiguration Dirac-Hartree-Fock method, with contributions of quantum electrodynamics and Breit interaction corrections taken into consideration. The calculated results of energy levels and wavelengths are in good agreement with experimental values and other calculations. The number of energy levels and wavelengths considered is larger than that of any other experiment or other calculations. The transition probabilities, line strengths, and oscillator strengths are also calculated where no other theoretical results and experimental values are available. Key words: multiconfiguration Dirac-Hartree-Fock, wavelengths, energy levels, transition probabilities, core-valence correlations. Nous utilisons la methode de Dirac-Hartree-Fock multi-configurations, incluant les corrections de Breit et d'electrodynamique quantique, afin d'obtenir les parametres spectraux (niveaux d'energie, longueurs d'onde, intensites de raie et forces d'oscillateur) des raies de resonance de Ba VIII, La IX et Ce X. Les resultats calcules pour les niveaux d'energie et les longueurs d'onde sont en bon accord avec les valeurs experimentales et d'autre calculs theoriques. Le nombre de niveaux d'energie et de longueurs d'onde est ici plus grand que dans tout autre ensemble existant de valeurs experimentales ou theoriques. Les probabilites de transition, les intensites de raie et les forces d'oscillateur sont aussi calculees la ou n'existent pas d'autre valeurs experimentales ou theoriques. [Traduit par la Redaction] Mots-cles : Dirac-Hartree-Fock multi-configurations, longueurs d'onde, niveaux d'energie, probabilites de transition, correlations creur-valence., 1. Introduction Ions of the indium isoelectronic sequence have three valence electrons outside a closed core [Kr] 4[d.sup.10] and provide a model for studying the effects of the strong correlation [...]

In this study, we investigate black hole solutions with toroidal horizons in scalar hair and dilaton gravity. First, we obtain the field equations in n-dimensions. Then, we propose different models (ansatz) and find the exact solutions for these types of ansatzs. These solutions are not asymptotically (anti) de Sitter or flat, except in one special case. We also show that the BTZ and BTZ-like solutions emerge from some of these solutions as a special case. We also show that when the event horizon radius increases, the temperature will be the same in various dimensions. The only difference is noticeable near the origin (this statement is clear from the figures). For these solutions, we obtained a new version of the Smarr formula. In addition, we show that the presence of the scalar field makes the black holes more stable near the origin, except for the BTZ case. In general, the presence of a scalar field is an important factor in black hole stability investigations. In the critical behavior analysis, we find that there is no evidence to show the existence of P-V criticality. Here, we present a class of interior solutions corresponding to the solution in a scalar hair gravity exterior. The solution obtained in the linear case was regular and well-behaved at the stellar interior. Key words: black hole solution, scalar hair, dilaton, P-V criticality, interior solution. Nous examinons ici les solutions trou noir avec horizons toroidaux en gravite chevelure scalaire/dilaton. Dans un premier temps, les equations de champ en n dimensions sont derivees, ensuite nous proposons differents modeles (ansatz) et nous trouvons des solutions exactes pour ces types d'ansatz. Ces solutions sont non asymptotiquement (anti) de Sitter ou plates, excepte dans un cas special. Nous montrons aussi que les solutions BTZ et de type BTZ emergent comme cas speciaux de ces solutions. Nous montrons egalement que lorsque le rayon de l'horizon devient de plus en plus grand, la temperature est la meme dans differentes dimensions. La seule difference est notable pres de l'origine (un fait rendu clair dans le diagrammed De ces solutions, emerge une nouvelle version de la formule de Smarr. Nous montrons aussi que la presence du champ scalaire rend les trous noirs plus stables pres de l'origine, a l'exception du cas BTZ. Nous pouvons dire en general que la presence du champ scalaire est un facteur important dans l'etude de la stabilite d'un trou noir. Dans l'analyse du comportement critique, aucune evidence de l'existence d'une criticite P-V n'apparait. Nous presentons ici une classe de solutions internes qui correspondent a la solution de gravite chevelue scalaire exterieure. La solution obtenue dans le cas lineaire est reguliere et continue dans l'interieur stellaire. [Traduit par la Redaction] Mots-cles: solution en trou noir, chevelure scalaire, dilaton, criticite P-V, solution interieure., 1. Introduction Gravity is still a bizarre concept in the universe. The Einstein theory of gravity (which is called general relativity (GR)) is an elegant theory for describing the gravitational [...]

In this work, we calculated the bosonic as well as fermionic propagators under classical homogeneous and constant magnetic and electric fields in a Euclidean space. For this, we will reassess Ritus' method for calculating the Feynman propagator. Key words: Feynman propagator, Ritus' method, electromagnetic field. Nous calculons ici les propagateurs bosonique et fermionique sous des champs electrique et magnetique classiques, constants et homogenes, le tout dans un espace euclidien. A cette fin, nous reexaminons la methode de Ritus pour calculer le propagateur de Feynman. [Traduit par la Redaction] Mots-cles: propagateur de Feynman, methode de Ritus, champ electromagnetique., 1. Introduction It is well known that the Feynman propagator is very important in quantum field theory and that, therefore, it must be calculated for the most diverse situations to [...]

In this paper, we obtain an anisotropic Bianchi type-II space-time with dark matter and modified holographic Ricci dark energy in the scale-covariant theory of gravitation. Exact solutions of the field equations are obtained by assuming (i) a negative constant value of the deceleration parameter, (ii) the component [[sigma].sup.1.sub.1] of the shear tensor [[sigma].sup.j.sub.1] is proportional to the mean Hubble parameter, and (iii) the gauge function [phi] is proportional to a power function of the average scale factor. We have also discussed some important physical aspects of the model, which is in agreement with the modern cosmological observations. Key words: Bianchi type-II model, holographic dark energy, modified Ricci dark energy, scale-covariant theory. Resume : Nous presentons ici un espace-temps de type II de Bianchi avec matiere noire et energie sombre de Ricci holographique modifiee dans une theorie de la gravite covariante d'echelle. Nous obtenons des solutions exactes pour les equations de champ, en supposant que (i) la valeur du parametre de deceleration est negative et constante, (ii) la composante [[sigma].sup.1.sub.1] du tenseur de cisaillement [[sigma].sup.j.sub.1] est proportionnelle a la valeur moyenne du parametre de Hubble et (iii) la fonction de jauge [phi] est proportionnelle a une fonction de puissance du facteur d'echelle moyen. Nous discutons egalement certains aspects importants du modele qui sont en accord avec les observations cosmologiques modernes. Mots-cles : modele de type II de Bianchi, energie sombre holographique, energie sombre de Ricci modifiee, theorie covariante d'echelle., 1. Introduction Observations of modern cosmology [1,2] have confirmed that our present-day universe is not only expanding, but also accelerating. It is believed that the cosmic acceleration is due to [...]

This paper mainly studied the thermocapillary migration of deformable droplets induced by periodic temperature boundary under microgravity conditions. The finite-difference/front-tracking (FD/FT) method was used to solve the Navier-Stokes equation coupled with the energy equation, and the continuum surface force (CSF) model was used to simplify the surface tension of the phase interface. The results showed that the maximum droplet migration velocity increased with the increase of temperature amplitude, and the droplet cycle period became shorter with the increase of temperature angular frequency. In the 1/4 cycle, the initial movement time of droplet decreased with the increase of temperature phase. If the phase was reversed, the initial movement direction of the droplet changed. With the increase of Reynolds number (Re), the droplet tended to maintain its motion inertia. Key words: periodic thermal boundary, front tracking method, Marangoni, microgravity. Nous etudions surtout la migration thermo-capillaire des gouttelettes deformables, induite par des frontieres de temperature periodiques dans des conditions de microgravite. Nous utilisons la methode de suivi d'interface (front tracking) aux differences finies (SI-DF/FD-FT) pour solutionner l'equation de Navier-Stokes couplee avec l'equation d'energie, alors que le modele de la force de surface dans le continuum (FSC/CSF) est utilise pour simplifier la tension de surface de l'interface de phase. Les resultats montrent que la vitesse maximale de migration des gouttelettes augmente avec la temperature. Aussi, la periode du cycle des gouttelettes devient plus courte avec l'augmentation de la frequence angulaire de la temperature. Dans le quart (1/4) de cycle, le temps de mouvement initial de la gouttelette diminue avec l'augmentation de la phase de la temperature. Si la phase est inversee, la direction du mouvement initial de la gouttelette change. Avec l'augmentation du nombre de Reynolds, la gouttelette tend a maintenir son mouvement inertiel. Mots-cles : frontiere thermique periodique, methode de suivi d'interface, Marangoni, microgravite., 1. Introduction In the study of heat transfer in multiphase flow, the phenomenon of fluid movement, which is caused by a temperature gradient or composition change on the liquid surface, [...]

Based on the non-orthogonal multiple-relaxation-time lattice Boltzmann method (MRT-LBM), natural convection in a porous square cavity with a pair of isothermally hot and cold blocks inside was studied numerically in the current study. The influence of arrangements (Cases 1, 2, 3, 4, and 5), spacing ratio (S), and size ratio (A) of the hot and cold sources and the Rayleigh number (Ra) on the heat exchange efficiency were studied. The results show that different arrangements produce different heat-transfer effects. Two arrangements, hot and cold blocks placed horizontally (Case 1) and a cold block located in the upper left corner while a hot block is located in the bottom right corner (Case 4), have better heat exchange performance than the other three cases because the flow directions of hot and cold fluids are closer to that of the heat transfer. Then, the influence of the spacing between blocks and the size of the blocks on the heat transfer rate was further studied in Cases 1 and 4. Heat transfer performance improved with increasing A. Additionally, the variation in the heat transfer performance with spacing is related to the arrangement and size ratio of the blocks. For Ra = [10.sup.4], [10.sup.5], and [10.sup.6], the best heat transfer characteristics were obtained in Case 1 when S = 0.05 and A = 0.20. For Ra = [10.sup.7], Case 4 exhibited the best heat transfer effect when S = 0.35 and A = 0.20. Key words: natural convection, porous cavity, internal hot and cold blocks, heat-flow coupling, multiple-relaxation-time lattice Boltzmann method (MRT-LBM). Sur la base de la methode de Boltzmann sur reseau, a multiples temps de relaxation et non orthogonale (MBR-MTR/MRT-LBM), nous etudions numeriquement la convection naturelle dans une cavite carree poreuse avec une paire de blocs gardes isothermement chaud et froid a l'interieur. Nous etudions l'influence de l'arrangement des facteurs physiques, tels l'arrangement des blocs chaud et froid (Cas 1, Cas 2, Cas 3, Cas 4 et Cas 5), le rapport d'espacement (S), le rapport de grosseur (A) et le nombre de Reynolds (Ra), sur l'efficacite de l'echange de chaleur. Les resultats montrent que differents arrangements produisent differents transferts de chaleur. Les blocs chaud et froid places horizontalement (Cas 1) et le bloc chaud place dans le coin superieur gauche avec le froid dans le coin inferieur droit (Cas 4), montrent un meilleur transfert de chaleur que les trois autres cas, puisque la direction d'ecoulement des fluides chaud et froid est plus proche de celle du transfert de chaleur. Ensuite, nous etudions l'influence de l'espacement entre les blocs et de la grosseur des blocs pour Cas 1 et Cas 4. La performance de transfert de chaleur augmente avec A. De plus, la variation de la performance de transfert est reliee a l'arrangement et a A. Pour Ra = [10.sup.4], [10.sup.5] et [10.sup.6], le meilleur transfert est obtenu dans le Cas 1 lorsque S = 0,05 et A = 0,20. Pour Ra = [10.sup.7], le Cas 4 voit son meilleur transfert a S = 0,35 et A = 0,20. [Traduit par la Redaction] Mots-cles : convection naturelle, cavite poreuse, blocs internes chaud et froid, couplage chaleur-ecoulement, methode de Boltzmann sur reseau a multiples temps de relaxation (MBR-MTR)., 1. Introduction Natural convection, where flow is caused by uneven densities of hot and cold fluids, widely exists in science and engineering applications, such as reactors, heat exchangers, microelectronic devices [...]

The ionosphere model is essential to satellite-based systems to accurately correct the ionospheric error encountered by satellite signals en route. The Levenberg-Marquardt backpropagation (LMBP) algorithm in the artificial neural network (ANN) was used in this work to predict the total electron content (TEC) within the trough of equatorial ionization anomaly (EIA) over Nigeria. Two sets of data were used over the period of three consecutive years (2011-2013) of high solar activity. The first set was used as an input to the ANN model and the second set of data was used as a target. Seventy percent of the data sets were used to train the network, 15% of the data were used for validation, and 15% used for testing. The performance of the model was assessed during specific quiet and disturbed geomagnetic conditions. The regression analysis of the model output was optimized by minimizing a cost function of the mean square error (MSE). The results of the errors, regression, and comparative analyses have revealed that the ANN model is able to predict accurate and reliable TEC that compares well with the actual experimental data at any geophysical conditions. Hence, this model would be useful to forecast TEC over Nigeria to a reliable threshold. Key words: LMBP-ANN, TEC, input, EIA, space weather. Un modele de l'ionosphere est essentiel dans un systeme base sur l'utilisation des satellites, afin de corriger de facon precise l'erreur ionospherique de la trajectoire du signal satellitaire. L'algorithme de retropropagation de LevenbergMarquardt (RPLM/LMBP dans un reseau neuronal artificiel (RNA/ANN) est le modele utilise ici pour predire le contenu electronique total (CET/TEC) dans la depression de l'anomalie d'ionisation equatoriale (AEI/EIA) au-dessus du Nigeria. Deux ensembles de donnees sont utilisees sur la periode de trois annees consecutives (2011-2013) de haute activite solaire. Le premier ensemble a ete utilise comme donnee d'entree pour le RNA et le second comme cible. 70 % des ensembles de donnees servent pour entrainer le reseau, 15 % pour le valider et 15 % pour le tester. La validite du modele est verifiee pendant des periodes de conditions geomagnetiques tranquilles et actives. L'analyse par regression des resultats du modele est optimisee en minimisant une fonction de cout de l'erreur quadratique moyenne (EQM/MSE). Le resultat pour les erreurs et les analyses comparatives montrent que le modele RNA est capable de predictions du CET precises et fiables, qui se comparent bien avec les valeurs experimentales actuelles pour toute condition geomagnetique. Ainsi, ce modele serait tres utile pour predire le CET au-dessus du Nigeria avec un bon niveau de fiabilite. [Traduit par la Redaction] Mots-cles : RPLM-RNA/LMBP-ANN, CET/TEC, entree, AEI/EIA, meteo spatiale., 1. Introduction The ionosphere is a region of the upper atmosphere extending from approximately 50 km to about 2000 km above the Earth's surface. This region contains amounts of electrons [...]

This research explores the Tsallis holographic quintessence, k-essence, and tachyon models of dark energy in the modified F(R, T) gravity framework with Granda-Oliveros cutoff. We have analyzed the energy density through [[rho].sub.[LAMBDA]] = [([alpha][H.sup.2] + [beta].sup.- [delta]+2]. We study the correspondence between the quintessence, k-essence, and tachyon energy density with the Tsallis holographic dark energy density in a flat FRW Universe. The reconstruction is performed for different values of Tsallis parameter [delta] in the region of [[omega].sub.[LAMBDA]] > -1 for the EoS parameter. This correspondence allows reconstruction of the potentials and the dynamics for the scalar field models, if we set some constraints for the model parameters, which describe the accelerated expansion of the Universe. Key words: THDE, Tsallis holographic dark energy, f(R, T) gravity, quintessence, k-essence, tachyon. Nous explorons la quintessence holographique de Tsallis, la k-essence et le modele tachyon de l'energie sombre dans le cadre de la gravite f (R, T) avec un seuil de coupure de Granda- Oliveros. La densite d'energie est analysee via [[rho].sub.[LAMBDA]] = [([alpha][H.sup.2] + [beta][??]).sup.-[delta]+2]. Nous etudions la correspondance entre la quintessence, la k-essence et la densite d'energie de tachyon avec la densite d'energie sombre holographique de Tsallis dans un univers FRW plat. La reconstruction se fait pour differentes valeurs du parametre de Tsallis [delta] dans la region [[omega].sub.[LAMBDA]] > -1 pour le parametre de l'equation d'etat. La correspond ance permet de reconstruire le potentiel et la dynamique pour les modeles de champs scalaires, si nous posons certaines contraintes pour les parametres du modele qui decrit l'expansion acceleree de l'univers. [Traduit par la Redaction] Mots-cles : energie sombre holographique de Tsallis, gravitef(R, T), quintessence, k-essence, tachyon., 1. Introduction Since the discovery of cosmic acceleration [1, 2] issues continue to arise in the fundamentals, such as what is dark energy (DE) and what does it interact with? [...]

This paper deals with the locally rotationally symmetric (LRS) Bianchi type-I universe model in Mimetic Gravity Theory assuming it is an extended form of General Relativity Theory. It was developed as a conformal transformation of the Einstein-Hilbert action from the Einstein frame to the Jordon frame. First, we have proposed a potential function to clarify the expansion of our universe by considering the general solutions of the field equations that originate from the action of the theory, including the Lagrange multipliers. Lastly, after having achieved the general equation of the state parameter [omega], we discussed whether the result corresponds to some fluids illuminating the expansion of the Universe or not. Key words: modified gravity theories, mimetic matter, conformal transforming, cosmology, locally rotationally symmetric (LRS) Bianchi type-I model. Nous considerons le modele de type-I de Bianchi localement symetrique sous rotation en theorie de gravite mimetique, prise ici comme une extension de la relativite generale, qui a ete presentee comme une transformation conforme de l'action de Einstein-Hilbert du cadre de Einstein au cadre de Jordan. Anterieurement, nous avons propose une fonction de potentiel dans le but de clarifier l'expansion de l'univers en considerant des equations de champ qui viennent de l'action de la theorie, incluant les multiplicateurs de Lagrange. Dernierement, apres avoir obtenu l'equation generale du parametre d'etat [omega], nous discutons si le resultat correspond a certains fluides permettant, oui ou non, de jeter un eclairage sur l'expansion de l'univers. [Traduit par la Redaction] Mots-cles : theories modifiees de la gravite, matiere mimetique, transformation conforme, cosmologie, modele de type I de Bianchi localement symetrique sous rotation., 1. Introduction General Relativity Theory (GRT) was the brainchild of Albert Einstein, which appeared in 1915, and was a groundbreaking theory that changed perceptions of gravity, with a unique approach [...]

In data-poor regions, modeled river temperatures are essential for predicting potential stressors for species at risk. With limited data from the Grand, Thames, and Sydenham rivers in southern Ontario, Canada, we evaluated simple mixed-effect regression models to predict water temperature using air temperature from nearby weather stations. Model performance was assessed for periods relevant to the fitness of the black redhorse (Moxostoma duquesni): June to August, when heat events may be likely; and May, when spawning occurs. All of the models performed better when trained on data from these periods, compared with using data from the entire growing season. The best model was a linear regression using 5 days of lagged air temperature. This model had a root mean square error for summer means of 1.5[degrees]C. The differences in prediction error at different times of year highlight the importance of considering species ecology in model interpretation. However, the improvement in model fit when using only data from the relevant time of year suggests that relatively simple models can be used effectively in a management arena when applied appropriately. Dans les regions pour lesquelles peu de donnees sont disponibles, les temperatures modelisees des rivieres sont d'importance fondamentale pour la prediction de facteurs de stress potentiels pour les especes en peril. A partir de donnees limitees pour les rivieres Grand, Thames et Sydenham, dans le sud de l'Ontario (Canada), nous avons evalue des modeles de regression a effets mixtes simples pour la prediction des temperatures de l'eau a partir de temperatures de l'air mesurees a des stations meteorologiques a proximite. La performance des modeles a ete evaluee pour des periodes importantes pour l'aptitude du chevalier noir (Moxostoma duquesnii), soit de juin a aout, quand des episodes de chaleur sont probables, et en mai, quand le frai a lieu. Tous les modeles ont donne de meilleurs resultats quand ils etaient prealablement entraines avec des donnees pour ces periodes que lorsque des donnees pour toute la saison de croissance etaient utilisees. Le meilleur modele est une regression lineaire integrant cinq jours de donnees de temperatures de l'air decalees (ecart-type moyen estival 1,5[degrees]C). Les differentes erreurs de prevision a differents moments de l'annee soulignent l'importance de tenir compte de l'ecologie de l'espece pour l'interpretation des modeles. L'amelioration du calage sur les modeles que produit l'utilisation de donnees seulement pour les periodes importantes de l'annee donne cependant a penser que, s'ils sont bien appliques, des modeles relativement simples peuvent etre utilises efficacement en gestion. [Traduit par la Redaction], Introduction Water temperature is one of the primary factors that determine the survival, growth, and reproduction of aquatic organisms in flowing systems (Wismer and Christie 1987; Caissie 2006; Hasnain et [...]

In the present paper, we have generalized the behaviors of the transit-decelerating to accelerating FRW cosmological model in f(R, T) gravity theory, where R and T are Ricci scalar and trace of the energy-momentum tensor, respectively. The solution of the corresponding field equations is obtained by assuming a linear function of the Hubble parameter H (i.e., q = [c.sub.1] + [c.sub.2]H), which gives a time-dependent deceleration parameter [Please download the PDF to view the formula], where [c.sub.3] and [c.sub.2] are arbitrary integrating constants (Tiwari et al. Eur. Phys. J. Plus, 131, 447 (2016); Ibid. 132,126 (2017)). There are two scenarios in which we explain the particular form of scale factor thus obtained: (i) by using the recent constraints from observational Hubble data (OHD) and joint light curves (JLA) data, which show a cosmic deceleration to acceleration and (ii) by using new constraints from supernovae type Ia union data, which show accelerating expansion of the universe (q < 0) throughout its evolution. We have observed that EoS parameter, energy density parameters, and important cosmological planes yield results compatible with the modern observational data. For the derived models, we have calculated various physical parameters as luminosity distance, distance modulus, and apparent magnitude versus redshift for both current supporting observations. Key words: f(R, T) gravity theory, modified gravity, deceleration parameter, transit universe, cosmological constant. Nous generalisons ici les comportements en transit de deceleration a acceleration d'un modele cosmologique FRW en gravite f(R, T), ou R et T sont le scalaire de Ricci et la trace du tenseur d'energie-impulsion respectivement. La solution des equations de champ correspondantes est obtenue en supposant une fonction lineaire du parametre de Hubble (i.e. q = c1 + [c.sub.2]H), ce qui mene a un parametre de deceleration (PD/DP) dependant du temps [Please download the PDF to view the formula] sont des constantes d'integration arbitraires (Tiwari et al. Eur. Phys. J. Plus, 131, 447 (2016); Ibid. 132,126 (2017)). Il y a deux scenarios dans lesquels nous expliquons la forme particuliere du facteur d'echelle obtenu de cette facon : (i) en utilisant les contraintes recentes des donnees observationnelles de H(z) (OHD) et des donnees JLA qui montrent un passage d'une deceleration vers une acceleration cosmique et (ii) en utilisant de nouvelles contraintes venant de l'union des donnees sur les supernovoe de type Ia, qui montrent un univers en expansion acceleree (q < 0) pour toute la duree de l'evolution. Nous notons que le parametre de l'equation d'etat (EdE/EoS), les parametres de densite d'energie et les importants plans cosmologiques, donnent des resultats compatibles avec les donnees observationnelles modernes. Pour les modeles derives ici, nous calculons differents parametres physiques, comme la distance de luminosite, le module de distance et la magnitude apparente vs le decalage vers le rouge pour les deux ensembles d'observations etudiees. [Traduit par la Redaction] Mots-cles : theorie de la gravite f (R, T), gravite modifiee, parametre de deceleration, univers en transit, constante cosmologique., 1. Introduction Until 1998 it was generally accepted by almost every scientist in cosmology and relativity that the cosmos is expanding, and the expansion rate is decreasing, because of gravity [...]

The influence of two-phase flows containing suspension particles, which are common in nature, on internal erosion with coupling effect of clogging remains unclear. This paper presents a three-dimensional coupled computational fluid dynamics and discrete element method (CFD-DEM) analysis of internal erosion considering different concentrations of suspension C (i.e., mass of the suspended particles in unit volume of fluid) in gap-graded granular soils with different fine fraction [F.sub.c] (i.e., the percentage by mass of the fine particles in the gap-graded sample). The influences of C and [F.sub.c] on the erosion and clogging behavior of soils are investigated from both the macroscopic and microscopic perspectives. It is found that for gap-graded samples being underfilled with [F.sub.c] = 15%, the suspension flow (i.e., influent fluid with suspending particles) decreases the cumulative eroded fine particle loss and the increasing rate of soil hydraulic conductivity due to clogging at the top of the sample. The degree of clogging is found to jointly be determined by both constriction size distribution and the suspension concentration. Clogging in a local area usually occurs with the formation of the clusters, which have a high resistance to the drag force applied by the fluid flow. Key words: gap-graded soil, erosion, clogging, suspension, fine fraction, constriction size. L'influence des ecoulements diphasiques contenant des particules en suspension, qui sont courantes dans la nature, sur l'erosion interne avec effet de couplage du colmatage (<< clogging >>) reste incertaine. Cet article presente une analyse tridimensionnelle de l'erosion interne par la dynamique des fluides computationnelle et la methode des elements discrets (CFD-DEM) couplees en tenant compte de differentes concentrations de suspension C (c'est-a-dire la masse des particules en suspension dans une unite de volume de fluide) dans les sols granulaires a granulometrie discontinue avec differentes fractions fines [F.sub.c] (c'est-a-dire le pourcentage en masse des particules fines dans l'echantillon a granulometrie discontinue). Les influences de la C et de la [F.sub.c] sur le comportement d'erosion et de colmatage des sols sont etudiees a la fois du point de vue macroscopique et microscopique. Il s'avere que pour les echantillons a granulometrie discontinue insuffisamment remplis de [F.sub.c] = 15 %, le flux de suspension (c'est-a-dire un fluide de penetration avec des particules en suspension) diminue la perte cumulative de particules fines erodees et le taux croissant de conductivite hydraulique du sol du au colmatage dans le haut de l'echantillon. On constate que le degre de colmatage est determine a la fois par la distribution de la taille de la constriction et la concentration de la suspension. Le colmatage dans une zone locale se produit generalement avec la formation des grappes qui ont une grande resistance a la force de trainee appliquee par l'ecoulement du fluide. [Traduit par la Redaction] Mots-cles: sol a granulometrie discontinue, erosion, colmatage, suspension, fraction fine, taille de la constriction., 1. Introduction Internal erosion may occur when the coarse grain group of a gap-graded sandy soil is unable to prevent the erosion of the fine particles under the action of [...]

Existing guidance on the installation of screw piles suggest that they should be installed in a pitch-matched manner to avoid disturbance to the soil that may have a detrimental effect on the in-service performance of the pile. Recent insights from centrifuge modelling have shown that installing screw piles in this way requires large vertical compressive (or crowd) forces, which is inconsistent with the common assumption that screw piles pull themselves into the ground requiring minimal vertical compressive force. In this paper, through the use of the discrete element method (DEM), the effects of advancement ratio, i.e., the ratio between the vertical displacement per rotation to the geometric pitch of the helix of the screw pile helix, on the installation resistance and in-service capacity of a screw pile is investigated. The findings are further used to assess the applicability of empirical torque capacity correlation factors for large diameter screw piles. The results of the investigation show that it is possible to reduce the required vertical compressive installation force by 96% by reducing the advancement ratio and that although over-flighting a screw pile can decrease the subsequent compressive capacity, it appears to increase the tensile capacity significantly. Key words: installation effects, screw piles, discrete element method (DEM). Les recommandations en vigueur pour les pieux a vis stipulent qu'ils doivent etre installes a un taux d'avancement d'un pas de vis par rotation du pieu, afin d'eviter la perturbation du sol et son effet nefaste sur les performances du pieu en service. De recentes modelisations en centrifugeuse ont montre que l'installation de pieux a vis de cette maniere necessite d'importantes forces de compression verticales (ou de reaction), ce qui est incompatible avec l'hypothese courante selon laquelle les pieux a vis s'enfoncent dans le sol par eux-memes en ne necessitant qu'une force de compression verticale minimale. La methode des elements discrets (DEM) est utilisee dans cet article pour etudier l'effet du rapport d'avancement, defini comme le rapport entre le deplacement vertical pour une rotation du pieu et le pas de vis de l'helice, sur la resistance a l'installation et les capacites en service du pieu. Les resultats sont ensuite utilises pour evaluer l'applicabilite des facteurs empiriques de correlation entre couple et capacite pour les pieux a vis de grand diametre. Il ressort de l'analyse des resultats qu'il est possible de reduire de 96 % la force de compression verticale necessaire a l'installation en reduisant le taux d'avancement et que, bien que la sur-rotation d'un pieu a vis puisse diminuer la capacite de compression, la capacite de traction semble augmenter de maniere significative. Mots-cles : effets d'installation, pieu a vis, methode des elements discrets (DEM)., 1. Introduction A screw pile is a form of displacement pile, which consist of a central steel shaft with one or more helices welded to the shaft at specific intervals [...]

This paper investigates the uplift capacity of horizontal plate anchors in sand through finite element analyses and centrifuge experiments. The finite element simulations adopt a sophisticated bounding surface plasticity model that accounts for stress- and density-dependent behaviour, as well as loading- and fabric-related anisotropic effects in sands. Failure mechanisms at peak anchor capacity show that failure occurs progressively, with a marked decrease in mobilised friction angle within the shear bands close to the anchor edge. Numerical simulations of a large set of centrifuge experiments on rectangular, strip, and circular plates at different relative densities and stress levels are in good agreement for dense conditions, but perform more poorly for loose conditions due mainly to the open cone yield surface in the bounding surface model. Equivalent comparisons with current limit equilibrium methods highlight the challenges in direct application of element-level strength equations. Finally, the paper proposes a modified limit equilibrium solution based on a 'rigid-block' failure mechanism extending to the soil surface, but with anchor factors that encompass the results from the finite element simulations. The modified solution provides a higher level of agreement with results from a large database of plate and pipeline test data than existing limit equilibrium methods. Key words: plate anchor capacity, bounding surface plasticity, centrifuge tests, sands, stress-level dependence. Cet article examine la capacite de soulevement des ancrages de plaques horizontales dans le sable par des analyses par elements finis et des experiences de centrifugation. Les simulations par elements finis adoptent un modele sophistique de plasticite de la surface limite qui tient compte du comportement dependant de la contrainte et de la densite, ainsi que des effets anisotropes lies a la charge et au tissu dans les sables. Les mecanismes de defaillance a la capacite maximale de l'ancre montrent que la defaillance se produit progressivement, avec une diminution marquee de l'angle de frottement mobilise dans les bandes de cisaillement pres du bord de l'ancre. Les simulations numeriques d'un grand nombre d'experiences de centrifugation sur des plaques rectangulaires, en bande et circulaires a differentes densites relatives et niveaux de contrainte sont en bon accord pour les conditions denses, mais ont de moins bons resultats pour les conditions laches, principalement en raison de la surface d'elasticite du cone ouvert dans le modele de surface limite. Des comparaisons equivalentes avec les methodes d'equilibre limite actuel mettent en evidence les defis lies a l'application directe des equations de resistance au niveau des elements. Enfin, le document propose une solution d'equilibre limite modifiee basee sur un mecanisme de rupture a << bloc rigide >> s'etendant a la surface du sol, mais avec des facteurs d'ancrage qui englobent les resultats des simulations par elements finis. La solution modifiee permet d'obtenir un niveau de concordance plus eleve avec les resultats d'une vaste base de donnees de tests sur plaques et sur conduites que les methodes d'equilibre limite existantes. [Traduit par la Redaction] Mots-cles : capacite d'ancrage des plaques, plasticite de la surface limite, essais de centrifugation, sables, dependance du niveau de contrainte., Introduction Plate anchors are used onshore as foundation elements for structures subjected to high uplift or lateral loads. They could also be an economical alternative to pile foundations for mooring [...]

A permeable pipe pile is proposed to accelerate the dissipation of excess pore-water pressure through drainage holes around the pile circumference into the pile's cavity. This investigation generalizes the permeable pile-soil interface as an impeded boundary, based on which a mathematical model for soil consolidation around the permeable pile is derived. Subsequently, the influence of opening pattern, drainage hole-to-pipe pile radius ratio, and opening ratio on the consolidation efficiency is numerically investigated. A total of 240 numerical cases with different drainage hole-to-pipe pile radius ratios, opening ratios, and hydraulic conductivity ratios are calculated to determine the permeable pile-soil interface parameter using back-analysis, and an approximate expression for interface parameter is obtained. Comparing against experimentally measured excess pore-water pressure dissipation, the proposed technique with impeded drainage boundary can provide good evaluations for drainage characteristics at the permeable pile-soil interface and consolidation behavior of the surrounding soil. It is found that the spatial distribution pattern of drainage holes has negligible influence on the consolidation efficiency. Increasing the opening ratio (with constant opening size) or reducing the drainage hole-to-pipe pile radius ratio (with constant opening ratio) can both accelerate the consolidation efficiency. Key words: permeable pile, analytical solution, interface parameter, impeded boundary, numerical calculation, back- analysis. Un pieu tubulaire permeable est propose pour accelerer la dissipation de l'exces de pression d'eau interstitielle par des trous de drainage autour de la circonference du pieu dans la cavite de celui-ci. Cette etude generalise l'interface pieu permeablesol en tant que limite entravee, sur la base de laquelle un modele mathematique pour la consolidation du sol autour des pieux permeables est derive. Par la suite, l'influence de la configuration des ouvertures, du rapport entre le rayon des trous de drainage et celui des pieux tubulaires, et du rapport des ouvertures sur l'efficacite de la consolidation est etudiee numeriquement. Un total de 240 cas numeriques avec differents rapports entre le rayon du trou de drainage et le rayon du pieu, rapports d'ouverture et rapports de conductivite hydraulique sont calcules pour determiner le parametre d'interface pieu permeable-sol en utilisant la retro-analyse, et une expression approximative pour le parametre d'interface est obtenue. Par rapport a la dissipation de la pression d'eau interstitielle excedentaire mesuree experimentalement, la technique proposee avec une limite de drainage entravee peut fournir de bonnes evaluations des caracteristiques de drainage a l'interface pieu permeable-sol et du comportement de consolidation du sol environnant. On constate que le schema de distribution spatiale des trous de drainage a une influence negligeable sur l'efficacite de la consolidation. L'augmentation du rapport d'ouverture (avec une taille d'ouverture constante) ou la reduction du rapport du rayon de trou de drainage et le pieu tubulaire (avec un rapport d'ouverture constant) peuvent toutes deux accelerer l'efficacite de la consolidation. [Traduit par la Redaction] Mots-cles : pieu permeable, solution analytique, parametre d'interface, limite entravee, calcul numerique, retroanalyse., 1. Introduction When a pile is driven into soft ground, excess pore-water pressure can be generated in the surrounding soil due to the penetration effect, resulting in ground heave, settlement, [...]

Many experiments cannot feasibly be conducted as factorials. Simulations using synthetically generated data are viable alternatives to such factorial experiments. The main objective of the present research is to develop a methodology and platform to synthetically generate spatially explicit forest ecosystems represented by points with a predefined spatial pattern. Using algorithms with polynomial complexity and parameters that control the number of clusters, the degree of clusterization, and the proportion of nonrandom trees, we show that spatially explicit forest ecosystems can be generated time efficiently, which enables large factorial simulations. The proposed method was tested on 1200 synthetically generated forest stands, each of 25 ha, using 10 spatial indices: Clark-Evans aggregation index; Ripley's K; Besag's L; Morisita's dispersion index; Greig-Smith index; the size dominance index of Hui; index of nonrandomness of Pielou; directional index and mean directional index of Corral-Rivas; and size differentiation index of Von Gadow. The size of individual trees was randomly generated aiming at variograms such as real forests. We obtained forest stands with the expected spatial arrangement and distribution of sizes in less than 1 h. To ensure replicability of the study, we have provided free, fully functional software that executes the stated tasks. Key words: preset spatial association, manifolds, mixed models, dictionary search, spatially explicit. Il n'est pas possible de realiser plusieurs experiences sous une forme factorielle. Les simulations qui utilisent des donnees generees synthetiquement sont des solutions de rechange valables a de telles experiences factorielles. L'objectif principal de ce projet est de mettre au point une methode et une plate-forme pour generer synthetiquement des ecosystemes forestiers spatialement explicites en les representant par des points selon un agencement spatial predefini. A l'aide d'algorithmes de complexite polynomiale et des parametres qui determinent le nombre de groupes, le degre de regroupement et la proportion d'arbres non aleatoires, nous montrons que des ecosystemes forestiers spatialement explicites peuvent etre generes dans un laps de temps adequat, ce qui permet de realiser des simulations factorielles de grande envergure. La methode proposee a ete testee a l'aide de 1200 peuplements forestiers de 25 ha generes synthetiquement en utilisant 10 indices spatiaux : l'indice de regroupement de Clark-Evans; l'indice K de Ripley; l'indice L de Besag; l'indice de dispersion de Morisita; l'indice de Greig-Smith; l'indice de dominance de taille de Hui; l'indice d'equitabilite de Pielou; les indices directionnel et directionnel moyen de Corral-Rivas; et l'indice de differenciation de taille de Von Gadow. La taille des arbres individuels a ete generee aleatoirement a partir de variogrammes representant de vraies forets. En moins d'une heure, nous avons obtenu des peuplements forestiers dont la disposition spatiale et la distribution des tailles etaient conformes aux attentes. Pour s'assurer de la reproductibilite de l'etude, un logiciel gratuit et entierement fonctionnel est disponible pour executer les taches enoncees. [Traduit par la Redaction] Mots-cles : association spatiale predefinie, collections, modeles mixtes, recherche dans un repertoire, spatialement explicite., 1. Introduction The computational advancements of the last half century allow complex spatially and temporally explicit investigations of the managed and unmanaged ecosystems (de Groot et al. 2010; Bryan et [...]

Rock creep behaviour is crucial in many rock engineering projects. Different approaches have been proposed to model rock creep behaviour; however, many cannot reproduce tertiary creep (i.e., accelerating strain rates leading to rock failure). In this work, the distinct element method (DEM) is employed, in conjunction with the rate process theory (RPT) of M.R. Kuhn and J.K. Mitchell (published in 1992) to simulate rock creep. The DEM numerical sample is built using a mixture of contact models between particles that combines the Flat Joint Contact Model and the Linear Model. Laboratory uniaxial compression creep tests conducted on intact slate samples are used as a benchmark to validate the methodology. Results demonstrate that, when properly calibrated, DEM models combined with the RPT can reproduce all creep stages observed in slate rock samples in the laboratory, including tertiary creep, without using constitutive models that incorporate an explicit dependence of strain rate on time. The DEM results also suggest that creep is associated with damage in the samples during the laboratory tests, due to new microcracks that appear when the load is applied and maintained constant at each loading stage. Key words: uniaxial compression multistage creep test, distinct element method (DEM), rate process theory (RPT), creep strain, tertiary creep. Le comportement de fluage des roches est crucial dans de nombreux projets d'ingenierie des roches. Differentes approches ont ete proposees pour modeliser le comportement de fluage des roches. Cependant, beaucoup ne peuvent pas reproduire le fluage tertiaire (c'est-a-dire l'acceleration des taux de deformation menant a la rupture de la roche). Dans ce travail, la methode des elements distincts (DEM) est utilise, en conjonction avec la theorie du processus de taux (RPT) de M.R. Kuhn et J.K. Mitchell (publie en 1992) pour simuler le fluage des roches. L'echantillon numerique DEM est construit en utilisant un melange de modeles de contact entre les particules qui combine le modele de contact a joint plat et le modele lineaire. Des tests de fluage par compression uniaxiale en laboratoire, effectues sur des echantillons d'ardoise intacts, servent de reference pour valider la methodologie. Les resultats demontrent que, lorsqu'ils sont correctement calibres, les DEM combines a la RPT peuvent reproduire toutes les etapes de fluage observees dans les echantillons de roche ardoisiere en laboratoire, y compris le fluage tertiaire, sans utiliser de modeles constitutifs qui incorporent une dependance explicite de la vitesse de deformation avec le temps. Les resultats duDEM suggerent egalement que le fluage est associe a des dommages dans les echantillons lors des tests en laboratoire, en raison de nouvelles microfissures qui apparaissent lorsque la charge est appliquee et maintenue constante a chaque etape de chargement. [Traduit par la Redaction] Mots-cles: essai de fluage a plusieurs etapes de compression uniaxiale, methode des elements distincts (DEM), theorie du processus de taux (RPT), deformation par fluage, fluage tertiaire., 1. Introduction The time-dependent (creep) behaviour of rocks is an essential factor for many geotechnical projects, such as caverns and tunnels (Zhang et al. 2012, 2015); rock bolts and rock [...]

In the present work, single ionization of the methane molecule is studied. The double differential cross section for the ejected electron is considered. The target is ionized by the effect of perturbation created by proton impact with high incident velocity. In our theoretical formalism, the one Coulomb wave model is employed in the framework of the first Born approximation, which means that the final state is considered as a product of a plane wave function for the scattered heavy particle and a Coulomb wave function for the ejected electron. The initial state is a product of a plane wave function for the fast incident charge and wave functions centered over the heavy nuclei to describe the active electron. In our formalism, the one Coulomb wave model is corrected by Salin factor to take into account the effect of the electron transfer to the continuum. The obtained results are compared to the available experimental data. Key words: cross section, methane molecule, 1CW model, Born approximation, single ionization. Ce travail etudie l'ionisation simple d'une molecule de methane. Nous considerons la section efficace doublement differentielle pour l'electron ejecte. La cible est ionisee par la perturbation generee par l'impact d'un proton incident a haute vitesse. Dans notre formalisme theorique, nous utilisons le cadre du modele de Coulomb a une onde dans la premiere approximation de Born, ce qui signifie que l'etat final est constitue du produit d'une onde plane pour la particule lourde diffusee et d'une onde de Coulomb pour l'electron ejecte. L'etat initial est un produit d'une onde plane pour le proton incident a haute vitesse et de fonctions d'onde centrees sur le noyau lourd pour decrire l'electron actif. Nous introduisons le facteur de Salin pour corriger le modele de Coulomb a une onde, afin de tenir compte de l'effet du transfert de l'electron dans le continuum. Les resultats obtenus sont compares aux donnees experimentales disponibles. [Traduit par la Redaction] Mots-cles : section efficace, molecule de methane, modele de Coulomb a une onde, approximation de Born, ionisation simple., 1. Introduction Studying the ionization of atoms and molecules by charged particles is important for a large number of areas, such as plasma physics, radiation physics, astrophysics, radiation therapy, and [...]

We present a comprehensive and elaborate study of W LVI (K-like [W.sup.55+]) by using multi-configuration Dirac-Fock method (MCDF). We have included relativistic corrections, QED (quantum electrodynamics) and Breit corrections in our computation. We have reported energy levels and radiative data for multipole transitions (i.e., electric dipole (E1), electric quadrupole (E2), magnetic dipole (M1), and magnetic quadrupole (M2)) within the lowest 142 fine-structure levels and predicted soft X-ray transition (SXR) and extreme ultraviolet transitions (EUV) from higher excited states to the ground state. We have compared our calculated data with energy levels compiled by NIST and other available results in the literature and the small discrepancies found with them are discussed. Because only a few of the lowest levels are available in the literature, for checking excitation energies of higher excited states we have performed the same calculations with the distorted wave method. Furthermore, we have also provided relative population for the first five excited states, with both the partition function and thermodynamic quantities for W LVI and studied their variations with temperature. We believe that our reported new atomic data of W LVI may be useful in identification and analysis of spectral lines from various astrophysical and fusion plasma sources and may also be beneficial in plasma modeling. Key words: EUV, SXR, partition function, atomic data, level population. Nous presentons une etude elaboree et exhaustive du W LVI ([W.sup.55+] de type K) en utilisant une methode de DiracFock multi-configurations (DFMC/MCDF). Ces calculs incluent les corrections relativistes de EDQ/QED (electrodynamique quantique) et de Breit. Nous presentons ici les niveaux d'energie et les donnees radiatives pour plusieurs transitions multipolaires (i.e., dipolaires electriques (E1), quadripolaires electriques (E2), dipolaires magnetiques (M1) et quadripolaires magnetiques (M2)) dans les 146 niveaux les plus bas de structure fine, avec les transitions a rayons X moux et UV extremes entre les etats excites et le fondamental. Nous comparons nos resultats de calcul avec les donnees sur les niveaux d'energie compilees par NIST et d'autres resultats trouves dans la litterature et nous discutons les petites divergences. Parce que peu de niveaux sont disponibles dans la litterature et afin de verifier les energies des niveaux de plus haute excitation, nous avons refait le calcul a l'aide de la methode des ondes distordues. De plus, nous donnons les populations relatives pour les cinq plus bas niveaux excites, avec la fonction de partition et les quantites thermodynamiques pour les deux modeles de W LVI et etudions leurs variations avec la temperature. Nous estimons que ces nouveaux resultats pour W LVI peuvent etre utiles dans l'identification de lignes spectrales en astrophysique et dans des sources de plasma de fusion et etre benefiques en modelisation de plasma. [Traduit par la Redaction] Mots-cles : UV extremes, rayons X mous, donnees atomiques, population des niveaux., 1. Introduction Specific physical properties of tungsten (W), such as its highest melting point and lower vapor pressure of all metals, position it as a potential candidate in fusion agency. [...]

In the present communication, we have studied the existence of wormholes described by a logarithmic shape function, in the exponential f(R, T) gravity given by f(R, T) = R + 2[xi][e.sup.[zeta]t] where [xi] and [zeta] are arbitrary constants, under three different sets of physical constraints. The logarithmic shape function is well behaved, satisfying all the necessary constraints for traversable and asymptotically flat wormholes. The obtained wormhole solutions are analyzed from the energy conditions for different values of involved physical constants. It has been observed that our proposed shape function for the exponential form of f(R, T) gravity represents the existence of exotic matter with a standard violation of the NEC. Moreover, for the trace T =0, for the general relativity case with R being replaced by R + 2, the wormhole geometry has been analyzed to prove the existence of exotic matter. Further, the behaviour of physical parameters, such as the energy density [rho], the trace T, and anisotropy parameter [DELTA], describing the geometry of the universe has been presented with the help of graphs. Key words: traversable wormholes, f(R, T) gravity, energy conditions, Schwarzschild metric, anisotropic parameter. Resume : Nous etudions ici l'existence de trous de ver decrits par une fonction de forme logarithmique, dans la gravite exponentielle f (R, T) donnee par f(R, T) = R + 2[xi][e.sup.[zeta]t] , ou [xi] et [zeta] sont deux constantes arbitraires et ce, pour trois ensembles de contraintes physiques. La fonction de forme logarithmique est derivable a tous les ordres (well behaved), satisfaisant toutes les contraintes necessaires pour des trous de ver traversables et asymptotiquement plats. Les solutions obtenues pour les trous de ver sont analysees a partir des conditions sur l'energie pour differentes valeurs des constantes physiques impliquees. Nous observons que notre fonction de forme proposee pour la forme exponentielle de la gravite f(R, T) signifie l'existence de matiere exotique avec la violation standard de la condition d'energie nulle (CEN/NEC). Aussi, pour la trace T = 0, dans le cas de la relativite generale avec R remplace par R + 2, la geometrie du trou de ver est analysee pour prouver l'existence de matiere exotique. De plus, nous presentons a l'aide de graphiques le comportement des parametres physiques decrivant la geometrie de l'univers, comme la densite d'energie [rho], la trace T et le parametre d'anisotropie A. [Traduit par la Redaction] Mots-cles : trous de ver traversables, gravite f(R, T), conditions sur l'energie, metrique de Schwarzschild, parametre d'anisotropie., 1. Introduction Wormhole geometry is a very hot subject among the investigators of the different modified theories of gravity. The idea of a wormhole was first communicated by Flamm [1] [...]