In this work, we introduce a mathematical model for the theory of generalized thermoelasticity with fractional heat conduction equation. The presented model will be applied to an infinitely long hollow cylinder whose inner surface is traction free and subjected to a thermal and mechanical shocks, while the external surface is traction free and subjected to a constant heat flux. Some theories of thermoelasticity can extracted as limited cases from our model. Laplace transform methods are utilized to solve the problem and the inverse of the Laplace transform is done numerically using the Fourier expansion techniques. The results for the temperature, the thermal stresses and the displacement components are illustrated graphically for various values of fractional order parameter. Moreover, some particular cases of interest have also been discussed.

Braking operation is a process which converts the kinetic energy and the potential energyof the vehicle into other energies. The major part of the mechanical energy is transformedinto heat. During the braking phase, the frictional heat generated at the interfacedisc–pads can lead to high temperatures. This phenomenon is even more important that thetangential stress as well as the relative sliding speeds in contact are important. Theobjective of this study is to analyse the thermal behavior of the full and ventilatedbrake discs of the vehicles using computing code ANSYS. The modeling of the temperaturedistribution in the disc brake is used to identify all the factors and the enteringparameters concerned at the time of the braking operation such as the type of braking, thegeometric design of the disc and the used material. The results obtained by the numericalsimulation are satisfactory compared with those of the specialized literature.

In order to limit the thermal gradient of plates during quenching and limit flatness issues, it is necessary to control the cooling. This control requires the knowledge of the cooling performances of the cooling device. This paper describes the equipments and procedure we developed for the on-line characterization of quenching. We illustrate the application of this methodology to the quench of Burns Harbor. After the austenitzing furnace, this quench is equipped with 3 cooling sections that have been characterized for several flow rates, for several speeds of plates and for the top and bottom sides of plates. Thanks to the collected data, heat fluxes have been calculated and correlations describing the cooling performances of the equipment have been built. These correlations have been implemented in a thermal model that gives the thermal state of a plate during cooling according to parameters like thickness of the plate, flow rates of the cooling sections, speed of the plate, and temperature after heating. Experimental and numerical results are discussed.

Over the past few years several technical efforts have been focused on continuous improvement of quench and tempered product at ArcelorMittal Burns Harbor plate mill facility with particular attention being given to optimization of the flatness of quenched product. Incremental improvement in quench line equipment and practices is being aided by computer-based modelling tools and specialized instrumentation. The paper describes the development of different tools used to control flatness after quench and tempering units. The detailed description of a 3D model designed to predict distortion such as edge waves, center buckles, longbows and crossbows during quenching is presented. The model developed with Abaqus is able to predict the evolution of plate temperature, thermal stresses, strains, and distortions during cooling. The water cooling system is represented by top and bottom movable surfaces where a heat flux depending on width, length and temperature is applied. The effect of phase transformation is approximated by a variation of the plate thermal expansion coefficient.

Le présent travail concerne une étude expérimentale de la croissance d'une bulle de vapeur unique dans un bain de FC-72 sous refroidi à pression atmosphérique. La configuration physique encore peu rencontrée dans la littérature se caractérise par des effets gravitationnels stabilisants : la bulle croît sous un élément chauffant (à flux pariétal imposé constant) à partir d'un site de nucléation artificiel indenté en son centre. Une étude de la dynamique de la croissance de la bulle est effectuée à partir d'un traitement d'images permettant d'accéder à l'évolution temporelle des différents paramètres géométriques associés à la bulle, tels que le diamètre maximal, la hauteur, le volume, les contours. Une analyse de certains paramètres permet de montrer notamment l'influence de la puissance de chauffe sur les transferts de masse et de chaleur. Par ailleurs, une observation par ombroscopie des différents modes d'instabilités convectives est présentée. L'influence de la présence d'incondensables sur le déclenchement de l'instabilité est discutée.

Many remote and local climate variabilities influence Antarctic sea ice at different time scales. The strongest sea ice teleconnection at the interannual time scale was found between El Niño–Southern Oscillation (ENSO) events and a high latitude climate mode named the Antarctic Dipole. The Antarctic Dipole is characterized by an out-of-phase relationship between sea ice and surface temperature anomalies in the South Pacific and South Atlantic, manifesting itself and persisting 3–4 seasons after being triggered by the ENSO forcing. This study examines the life cycles of ENSO warm and cold events in the tropics and associated evolution of the ADP in high latitudes of the Southern Hemisphere. In evaluating the mechanisms that form the ADP, the study suggests a synthesized scheme that links these high latitude processes with ENSO teleconnection in both the Pacific and Atlantic basins. The synthesized scheme suggests that the two main mechanisms responsible for the formation/maintenance of the Antarctic Dipole are the heat flux due to the mean meridional circulation of the regional Ferrel Cell and regional anomalous circulation generated by stationary eddies. The changes in the Hadley Cell, the jet stream in the subtropics, and the Rossby Wave train associated with ENSO link the tropical forcing to these high latitude processes. Moreover, these two mechanisms operate in phase and are comparable in magnitude. The positive feedback between the jet stream and stationary eddies in the atmosphere, the positive feedback within the air-sea-ice system, and the seasonality all reinforce the anomalies, resulting in persistent Antarctic Dipole anomalies.

Une étude numérique est effectuée sur des brûleurs poreux qui simulent la combustion d'un combustible solide ou liquide. L'air et un mélange contenant 30 % d'O2 et 70 % N2 sont utilisés comme oxydant à des vitesses d'injection de 2,7 à 4 cm.s-1 correspondant aux systèmes de conditionnement d'air des vaisseaux spatiaux. Le système des équations de Navier-Stokes et des équations de conservation des espèces est résolu par la simulation numérique directe. L'approche numérique est centrée sur l'influence du champ gravitationnel sur la géométrie de la flamme, les limites d'extinction et le transfert de chaleur de la flamme vers la surface du brûleur. Les résultats du modèle indiquent que l'état stationnaire en phase gazeuse soit atteint au bout de 2,5 s, correspondant à l'observation expérimentale.

Closely spaced continuous temperature profiles from expendable bathythermographs launched along two sections across the Drake Passage and western Scotia Sea in the summer 1981–1982 are used to examine the vertical medium-scale (∼10–100 m) temperature fine structure. The large-scale temperature structure across the frontal regimes characteristic of the Antarctic Circumpolar Current and the cross-frontal structure of the upper ocean are discussed. In the Drake Passage the heat content drops about 0.5 × 102 Kcal cm−2 (2 × 109 J m−2) across the Subantarctic Zone and 0.9 × 102 Kcal cm−2 (3.6 − 109 J m−2) across the Polar Front. In the Scotia Sea the heat content changes across the front are not as prominent. The statistical model of Joyce (1977) is used to quantify the heat fluxes across the fronts produced by the medium-scale temperature interleaving. In the Drake Passage the estimated heat flux is 0.32 × 10−3 °C m s−1 (1.3 × 103 W m−2) across the Subantarctic Front and 0.46 × 10−3 °C m s−1 (1.9 × 103 W m−2) across the Polar Front. In the Scotia Sea the estimated heat flux is larger in the Polar Front reaching 0.71 × 10−3 °C m s−1 (2.9 × 103 W m−2). The medium-scale fine structure heat fluxes are about 10% of the existing estimates of the mesoscale eddy heat fluxes and comparable to heat fluxes associated with the meridional flow of deep and bottom waters across the Antarctic Circumpolar Current.

Nous proposons une méthode d'estimation du flux de chaleur dans un outil de coupe lors d'une opération d'usinage par tournage et fraisage. Le modèle du comportement thermique de l'outil, reliant ce flux à la température mesurée en un point de l'outil, est obtenu au sens de l'identification de système non entier. Nous réalisons pour cela un dispositif de mesure de la température dans l'outil ainsi qu'un banc expérimental de caractérisation permettant de mesurer et de contrôler le flux de chaleur appliqué sur l'outil. Le modèle obtenu, après la phase d'identification des paramètres, permet de calculer la réponse impulsionnelle. Cette réponse est alors utilisée dans une procédure d'estimation séquentielle du flux.