Conduction

Numerical simulations were used to investigate natural radiation and convection interactions in small rooms with three-dimensional geometry. The opposite vertical walls are heated and cooled, while the other walls are supposed to be fixed. Governance flow, momentum equations, and radiative conversion are solved using Ansys Fluent CFD. In estimating thermal terminology, a second-degree wind diagram and a dual solution algorithm are used. The cubic box is filled with air and the flow is considered protective. Air characteristics are assumed to be constant, except for the difference in density in which a Bosnic approximation is used. The surface heat model (S2S) is used as the radiation transfer model. The arithmetic field is a square container Length of the edge = 0.225 m In a surrounding environment at T = 293 K. One of the walls of the case is heated up to 473 K. Note that the radiation from the opposite wall is high, with the improved model. Radiant heat transfer is reduced. I. INTRODUCTION Natural convection and heat transfer by heat radiation in fluid-filled cavities have received much attention in recent years due to its relationship to the thermal performance of engineering applications such as cooling electronic components, electrical boxes, assembler designs, solar designs, heat exchangers, etc.. Therefore, the common characteristics of natural convection and heat transfer by heat radiation are more important. The study of heat transfer in the room was the main topic of the researchers due to a wide range of applications in engineering and working life. It finds its application from cooling the nuclear reactor to removing heat from the micro-electronic components as well as for designing the room air conditioning, thermal design for commercial buildings, cold storage, oven and many more. In addition to a wide range of applications, the simultaneous thought of wall conduction and convection in fluid flow remains an exciting area of research in recent decades. Several articles can be found in the literature to study natural convection in the can. There are many boundary conditions that can be taken into consideration, but the most complex and practically applicable area of least study has been found in the literature. Most of the areas already studied are bottom warming or lateral warming. But in this study, we studied a viable limit state with associated heat transfer. Energy has long been a major topic of discussion among researchers. During any development program for any technology, energy consumption has always been of great importance. An important part of the total energy consumed in the useful life of any building is the operating capacity. This involves maintenance and, most importantly, the energy involved in maintaining the building in comfortable thermal and visual conditions. The building energy analysis tool used before starting any project aims to reduce this operating capacity. It is important to understand that this decrease in energy consumption must be achieved without regard to low performance. Therefore, the building should provide a comfortable environment compared to its external environment. Previous studies have shown the fact that the passenger quickly responds to any discomfort to restore his comfort, but this can negatively affect energy consumption. Therefore, accurate prediction of thermal comfort is very important when designing a building to maintain less energy consumption.

The absorption of energy from microwave frequency electromagnetic fields by carbon nanotubes is investigated by measuring the heating rate of dispersions of carbon nanotubes in silicone oil. Microwave absorbance of silicone oil is enhanced by 500 times with the addition of as little as 0.04 wt% carbon nanotubes. The removal of residual iron catalyst is found to have little effect on the microwave absorbance; an acid based surface modification however causes the enhancement to be lost, with the performance little better than carbon black. As-synthesized tubes showed a percolation threshold of $0.025 wt% for both conductivity and microwave absorbance. The efficient energy absorption is explained by a mechanism of conduction loss in the samples.

In seeking to understand the way in which heat is transferred from hotter to cooler regions of the Earth, it is important to have a general understanding of the physical composition of the Earth and, its various regions in which heat is transferred. This essay will provide a brief description of Earth's composition, and clarify what is entailed in each heat transfer process. It will seek to define and clarify their differences, and identify how each discussed process plays an important role in transferring heat from the hotter regions of the Earth to cooler regions.

By measuring the total energy flow from an optical device, we can develop new design strategies for thermal stabilization. Here we present a comprehensive model for heat exchange between a semiconductor laser diode and its environment that includes the mechanisms of conduction, convection, and radiation. We perform quantitative measurements of these processes for several devices, deriving parameters such as a laser's heat transfer coefficient, and then demonstrate the feasibility of thermal probing for the nondestructive wafer-scale characterization of optical devices.

In this present work the effects of temperature dependent viscosity and thermal conductivity on the coupling of conduction and Joule heating with MHD free convection flow along a semi-infinite vertical flat plate have been analyzed. The governing boundary layer equations with associated boundary conditions for this phenomenon are transformed to non-dimensional form using the appropriate variables. By the help of the implicit finite difference method with Keller-box scheme the resulting non-linear system of partial differential equation is then solved numerically. The purpose of this paper is to study the skin friction coefficient, the surface temperature, the velocity and the temperature profiles over the whole boundary layer for different values of the Prandtl number Pr, the magnetic parameter M, the thermal conductivity variation parameter γ, the viscosity variation parameter ε and the Joule heating parameter J. The results indicate that the flow pattern, temperature field and rate of heat transfer are significantly dependent on the above mentioned parameters. The local skin friction co-efficient and the surface temperature profiles for different values of ε are compared with previously published works and are found to be in good agreement.

An understanding of the mechanisms of heat transfer is becoming increasingly important in today’s world. Conduction and convection heat transfer phenomena are found throughout virtually all of the physical world and the industrial domain. A thermal insulator is a poor conductor of heat and has a low thermal conductivity. In this paper we studied that Insulation is used in buildings and in manufacturing processes to prevent heat loss or heat gain. Although its primary purpose is an economic one, it also provides more accurate control of process temperatures and protection of personnel. It prevents condensation on cold surfaces and the resulting corrosion. We also studied that critical radius of insulation is a radius at which the heat loss is maximum and above this radius the heat loss reduces with increase in radius. We also gave the concept of selection of economical insulation material and optimum thickness of insulation that give minimum total cost.

En este trabajo se evaluaron algunos aspectos para el diseño de un condensador acoplado a una turbina de vapor, por lo cual se trabajó con un condensador de superficie, ya que estos son utilizados comúnmente para la condensación entre agua y vapor proveniente de una turbina, Teniendo en cuenta esto se diseñó acorde con las dimensiones y magnitudes trabajadas comúnmente para estos intercambiadores de calor, además para este diseño se utilizó la metodología del libro de procesos de transferencia de calor de Donald Kern, apoyándose de las normas TEMA y otros libros de transferencia de calor.

En este trabajo se evaluaron algunos aspectos para el diseño de un condensador acoplado a una turbina de vapor, por lo cual se trabajó con un condensador de superficie, ya que estos son utilizados comúnmente para la condensación entre agua y vapor proveniente de una turbina, Teniendo en cuenta esto se diseñó acorde con las dimensiones y magnitudes trabajadas comúnmente para estos intercambiadores de calor, además para este diseño se utilizó la metodología del libro de procesos de transferencia de calor de Donald Kern, apoyándose de las normas TEMA y otros libros de transferencia de calor.

This paper proposes to address the most significant performance problems within the field of directed improvisation. Focusing mainly on the two main methods of this practice, Soundpainting and Conduction®, the dissertation consists of four chapters. The first two describe the historical context and the basic structure of the organization and functioning of each of the methods by addressing their communication systems, and practical aspects. On the third and fourth chapters it presents a comparison of both from the perspective of compositional logic against the reasoning of the improvisation group, followed by an observation and analysis of performance problems that occur in the methods here addressed, by interviews with practitioners of Soundpainting and Conduction® and empirical experiences with students of UFMG .

The use of CFD codes for the analysis of the hydrogen behaviour within NPP containments during severe accidents has been increasing during last years. In this paper, the adaptation of a commercial multi-purpose code to this kind of problem is explained, i.e. by the implementation of models for several transport and physical phenomena like: steam condensation onto walls in presence of non-condensable gases, heat conduction, fog and rain formation, material properties and criteria for assessing the hydrogen combustion regime expected. The code has been validated against several experiments in order to verify its capacity to simulate the following phenomena: plumes, mixing, stratification and condensation. Moreover, two tests in an integral large enough experimental facility have been simulated, showing that the well-mixed and stratified conditions of the test were reproduced by the code. Finally, an example of a plant application demonstrates the ability of the code in this kind of problems.

This paper concerns the effects of conduction and viscous dissipation on natural convection flow of an incompressible, viscous and electrically conducting fluid in the presence of transverse magnetic field. Numerical solutions for the governing momentum and energy equations are given. A discussion has been provided for the effects of magnetic parameter, Prandtl number, conjugate conduction parameter and viscous dissipation parameter on two-dimensional flow. Results for the details of the velocity, temperature distributions as well as the skin friction and the rate of heat transfer are shown graphically. Also the numerical values of the surface temperature distributions are presented in tabular form.

Link design for optical communication systems requires accurate modeling of nonlinear propagation in fibers. This topic has been widely analyzed in last decades with partial successes in special conditions, but without a comprehensive solution. Since the introduction of coherent detection with electronic signal processing the scenario completely changed because this category of systems shows better performances in links without in-line dispersion management. This change to uncompensated transmission allowed to modify the approach in the study of nonlinear fiber propagation and in recent years a series of promising analytical models have been proposed. In this paper, we present an experimental validation over different fiber types of an analytical model for nonlinear propagation over uncompensated optical transmission links. Considering an ultra-dense WDM system, we transmitted ten 120-Gb/s PM-QPSK signals over a multispan system probing different fiber types: SSMF, PSCF and NZDSF. A good matching was found in all cases showing the potential of the analytical model for accurate performance estimation that could lead to powerful tools for link design.

The transient heat conduction problems in one-dimensional multi-layer solids are usually solved applying conventional techniques based on Vodicka's approach. However, if the thermal diffusivity of each layer is retained on the side of the heat conduction equation modified from the application of the separation-of-variables method where the time-dependent function is collected, then the modified heat conduction equation by itself represents a transparent statement of the physical phenomena involved. This 'natural' choice so simplifies unsteady heat conduction analysis of composite media that thermal response computation reduces to a matter of relatively simple mathematics when compared with traditional techniques heretofore employed. Ó

This paper examines recent studies within a general project, aimed at writing down the lexicons of a Conductor's body signals. Three observational studies focusing, respectively, on the semantic area of intensity and on the modality of gaze, through annotation of several fragments of orchestra and choir conduction in concert and rehearsal, discovered a total of 100 signals of intensity in various modalities, out of which, 21 intensity gestures and 20 conducting items of gaze. Subsequent perception studies on a subset of these signals reveal slight differences in interpretation by music Experts, Non-Experts and Amateurs, but confirm their comprehensibility, probably due to their underlying semiotic devices, the same holding also in everyday life gestures and gaze.

Comparison and prediction of the experimental XANES spectrum is a good measurement of the quality of the electronic structure calculations employed, and their ability to predict electronic transitions in solids. Here we present a comparison between BLYP + U and hybrid-BLYP calculations regarding the geometric, magnetic and electronic structures of a-Fe 2 O 3 (hematite). Several values of U and different percentages of Fock-exchange have been screened to see how their contributions affect different properties of hematite, paying particular attention to the electronic structure. To estimate the quality of the various methods the calculated density-ofstates were compared to the experimentally collected XANES spectrum of the iron K-edge, providing information about the orbitals describing the conduction band. We find that in agreement with previous studies DFT + U and hybrid-functional simulations can correctly predict the character of the valence band, but only Fock-exchange higher than 30% or U-values equal or larger than 6 eV properly reproduce the order between the t g and e orbitals in the conduction band, and can, therefore, be used to study and predict XANES spectra and electronic transitions in hematite.

Heat transfer characteristics for a falling turbulent liquid film flow over a fin are analyzed using the conjugate convection-conduction theory. Numerical results are obtained from a simultaneous solution of the energy equations of the fluid and the fin. Results are presented for the fin temperature distribution, dimensionless heat transfer coefficients, local heat fluxes, and fin efficiencies.

En el presente trabajo analizo una de las técnicas musicales cuyo uso se ha extendido en los últimos años en Argentina, la “dirección por señas”, a través de la práctica que alrededor de doce músicos -incluida la etnógrafa- realizamos en el grupo de improvisación “Bandalup”. A través de estas performances podemos abordar la incidencia tanto de la corporalidad como de la escucha en la construcción intersubjetiva de la composición musical en tiempo real y analizar las formas en las que el conocimiento musical se actualiza a partir de experiencias sensorio-emotivo-corporales. Es intención aquí retomar y actualizar nuevas metodologías etnográficas como la acustemología (Feld 2013), la auto-etnografía (Ellis y Bochner 1996) y la investigación artística (López Cano y Ursula San Cristóbal Opazo 2014), y proponer la escucha participante (Polti 2011) y la biografía sonora (Polti 2012) como parte de este abordaje teórico-metodológico pluriperspectual.

Conduction transfer function (CTF) is widely used to calculate conduction heat transfer in building cooling/heating loads and energy calculations. It can conveniently fit into any load and energy calculation techniques to perform conduction heat transfer calculations. There are three popular methods, direct root-finding (DRF) method, state-space (SS) method and frequency-domain regression (FDR) method to calculate CTF coefficients. The limitation of a methodology possibly results in imprecise or false CTF coefficients. This paper investigates the applicability of three methods as Fourier number and thermal structure factor are varied and in detail explains the sources that introduce error in the CTF solutions. The results show that the calculation error of SS and DRF methods becomes increasing as the reciprocal of the product of Fourier number and thermal structure factor becomes increasing. The maximal error even reaches almost 100%. However, the calculation error of FDR method always remains within 1% no matter how Fourier number and thermal structure factor are varied. Thus, FDR method is more robust and reliable than SS and DRF methods. And it is more practical to calculate CTF coefficients and may be a better choice to calculate the cooling/heating loads for building structures for the architect/designer.

The purpose of this study was to test the feasibility of neodymiumyttrium-aluminum-garnet (Nd-YAG) laser photocoagulation of the atrioventricular (A V) node to control the ventricular rate during rapid atrial rhythms without creating A V block. In 12 dogs on normothermic cardiopulmonary bypass, short laser pulses were delivered to an area between the coronary sinus orifice and the site of the most proximally recorded His deflection until second degree A V block occurred at a paced atrial rate of 200 beats/min.

The purpose of this study is to implement a new analytical method (the DTM-Padé technique, which is a combination of the differential transform method (DTM) and the Padé approximation) for solving Navier-Stokes equations. In this letter, we will consider the DTM, the homotopy perturbation method (HPM) and the Padé approximant for finding analytical solutions of the three-dimensional viscous flow near an infinite rotating disk. The solutions are compared with the numerical (fourth-order Runge-Kutta) solution. The results illustrate that the application of the Padé approximants in the DTM and HPM is an appropriate method in solving the Navier-Stokes equations with the boundary conditions at infinity. On the other hand, the convergence of the obtained series from DTM-Padé is greater than HPM-Padé.

The research reported in this paper has focused on the different modes of heat transfer – conductive (to the substrate), conductive and convective (to the environment) and radiative (to the environment) – from an on-chip resistance temperature detector (RTD). The study has been carried out at various input voltages, various pressures ranging from atmospheric to vacuum, and for two classes of platforms for the device – thermal insulators (glass wool and ceramic), and a thermal conductor (aluminum block). The transient temperature–time response of the RTD under the various conditions stated above was recorded. A heat transfer model approximately accounting for all the modes of heat transfer was introduced. The calibration parameters of the model allowed us to quantify the different modes of heat transfer. The model uncovers the fact that the heat losses to the environment via conduction and convection are almost as much as the heat lost by radiation (radiative effects were unequivocally confirmed experimentally). Compared to these losses, conductive heat losses from the RTD to its underlying substructure are far more dominant (almost five times). We also give an analysis originating from the exact form of conservation of energy and demonstrate that the use of the simplified model has led to the most dominant heat transfer mode of conduction to the substrate being underestimated by no more than 7.89% (at the highest input power tested).

Green's function approach provides a new possibility of analytical procedure for heat transfer analysis of structures in fire. In many cases, it has been applied successfully to predict the temperature field. Heat transfer analysis of structure members protected by intumescent paint is complicated by active expansion of the base coat at elevated temperature. Because of this complex thermal behavior of intumescence, as well as commercial concern about the release of information, very little research has been reported in the literature. In this article, a Green's function method based on a one-dimensional reduced heat transfer model is presented. The highly nonlinear thermal conductivity of the intumescent paint is simplified to be temperature-independent to yield analytically tractable solutions of heat equations. The proposed approach is verified against the experimental investigation as well as finite-element analysis.

The combined pyrolysis and steam-gasification of petroleum vacuum residue was performed using a 5-kW aerosol-flow solar chemical reactor tested in a high-flux solar furnace in the temperature range 1420-1567 K. The feedstock was continuously injected as a liquid spray at 423 K into the reactor's cavity along with a coaxial steam flow at a H 2 O=C molar ratio in the 1.1-7.2 range, and directly exposed to concentrated solar radiation at concentration ratios exceeding 1800 suns. The degree of chemical conversion after a single pass of 1-s residence time attained 50% at 1472 K, producing high quality syngas of composition 68% H 2 , 15% CO, 14% CO 2 , and 2% CH 4. The process performance indicators, namely, carbon conversion and energy efficiency were generally inferior to those obtained for the solar steam-gasification of petcoke under comparable operating conditions.

The heat transfer and the U-values of wall layers in traditional North African houses in Libya have been estimated. The locally produced building materials during 1970's were used in the construction of such buildings. These materials were limited to bricks, tiles, cement plasters, mortar and ground soils without any insulation components. The masonry construction of these houses was based on concrete-backed stone masonry made of limestone bricks joined by mortar forming the outer walls of the building envelope. Based on the periodic seasonal weather conditions, within the Libyan cost region during summer and winter, measured thermal conductivity values were used to implement such seasonal variation of heat flow and the temperature variations through the walls. The estimation of the U-values is based on measurements and calculations. The experimental measured thermal conductivity values were obtained using the Hot Disk method known as Gustafsson's probe. The numerical calculations were done using an analytical model that considers different wall and floor constructions which are characteristics of such houses. According to the obtained results, the U-values were quite high and therefore, several suggestions have been proposed to improve the thermal loading performance that will lead to a reasonable human comfort and reduce energy consumption.

Critically understanding the `standard candle'-like behavior of Type Ia supernovae requires understanding their explosion mechanism. One family of models for Type Ia Supernovae begins with a deflagration in a Carbon-Oxygen white dwarf which greatly accelerates through wrinkling and flame instabilities. While the planar speed and behavior of astrophysically-relevant flames is increasingly well understood, more complex behavior, such as the flame's response to stretch and curvature, has not been extensively explored in the astrophysical literature; this behavior can greatly enhance or suppress instabilities and local flame-wrinkling, which in turn can increase or decrease the bulk burning rate. In this paper, we explore the effects of curvature on both nuclear flames and simpler model flames to understand the effect of curvature on the flame structure and speed.

This paper reports an experimental study on convective boiling heat transfer of nanofluids and de-ionized water flowing in a multichannels. The test copper plate contains 50 parallel rectangular minichannels of hydraulic diameter 800 µm. Experiments were performed to characterize the local heat transfer coefficients and surface temperature using copper-water nanofluids with very small nanoparticles concentration. Axial distribution of local heat transfer is estimated using a non-intrusive method. Only responses of thermocouples located inside the wall are used to solve inverse heat conduction problem. It is shown that the distribution of the local heat flux, surface temperature, and local heat transfer coefficient are dependent on the axial location and nanoparticles concentration. The local heat transfer coefficients estimated inversely are close to those determined from the correlation of Kandlikar and Balasubramanian [32] for boiling water. It is shown that the local heat flux, local vapor quality, and local heat transfer coefficient increase with copper nanoparticles concentration. The surface temperature is high for de-ionized water and it decreases with copper nanoparticles concentration.

Cardiac conduction defects associate with mutations in SCN5A, the gene encoding the cardiac Na ϩ channel. In the present study, we characterized a family in which the proband was born in severe distress with irregular wide complex tachycardia. His older sister died at 1 year of age from severe conduction disease with similarly widened QRS-complexes. Mutational analysis of SCN5A in the proband demonstrated compound heterozygosity for a nonsense mutation (W156X), inherited from the father, and a missense mutation (R225W), inherited from the mother. Genotyping on DNA extracted from tissue from the deceased sibling revealed the same SCN5A genotype. Injection of cRNA encoding the W156X mutation in Xenopus oocytes did not produce any current. The R225W substitution neutralizes the third Arg residue within the voltage-sensing segment of domain I. Expression studies showed that this mutation leads to a severe reduction in I Na and is also associated with gating changes. Histological examination of the heart from the deceased sibling revealed changes consistent with a dilated type of cardiomyopathy and severe degenerative abnormalities of the specialized conduction system. The occurrence of compound heterozygosity for these two mutations implies that the proband carries solely severely dysfunctional cardiac Na ϩ channels. This explains his severe phenotype and that of his deceased sister who had been a carrier of the same genotype. The morphological changes within the heart of the deceased sibling may have occurred secondary to the Na ϩ channel abnormality and contributed to the severity of the disorder in this individual. (Circ Res. 2003;92:159-168.)

Background-Two principal mechanisms are thought to be responsible for Brugada syndrome (BS): (1) right ventricular (RV) conduction delay and (2) RV subepicardial action potential shortening. This in vivo high-density mapping study evaluated the conduction and repolarization properties of the RV in BS subjects. Methods and Results-A noncontact mapping array was positioned in the RV of 18 BS patients and 20 controls. Using a standard S 1 -S 2 protocol, restitution curves of local activation time and activation recovery interval were constructed to determine local maximal restitution slopes. Significant regional conduction delays in the anterolateral free wall of the RV outflow tract of BS patients were identified. The mean increase in delay was 3-fold greater in this region than in control (Pϭ0Ͻ0.001). Local activation gradient was also maximally reduced in this area: 0.33Ϯ0.1 (meanϮSD) mm/ms in BS patients versus 0.51Ϯ0.15 mm/ms in controls (PϽ0.0005). The uniformity of wavefront propagation as measured by the square of the correlation coefficient, r 2 , was greater in BS patients versus controls (0.94Ϯ0.04 versus 0.89Ϯ0.09

So-called isothermal calorimeters are often built on the heat conduction principle. This may sound as a contradiction, as heat conduction is a result of non-isothermal conditions, but most measurements with microcalorimeters and other such instruments are essentially isothermal as the temperature differences within the instruments are in the order of 10 mK. This paper presents simple methods to estimate the temperature changes within a sample in a heat conduction calorimeter during a measurement. It also shows that the determination of activation energy is normally not disturbed by these small temperature changes. In addition to the heat production rate in the sample, the thermal properties of the sample and the calorimeter are needed as input to the calculations. #

This paper deals with the performance evaluation of the collapsed dimension method (CDM) and the discrete transfer method (DTM) in terms of computational time and their abilities to provide accurate results in solving radiation and/or conduction mode problems in a 2-D rectangular enclosure containing an absorbing, emitting and scattering medium. For some pure radiation cases, studies were made for two representative benchmark problems dealing with radiative equilibrium and non-radiative equilibrium. For the combined mode, the transient conduction and radiation problem was solved. The alternating direction implicit scheme was used for the solution of the finite difference part of the energy equation. For the three types of problems considered, tests were performed for a wide range of aspect ratio, extinction coefficient, scattering albedo, conduction-radiation parameter and boundary emissivity. For pure radiation problems, results from the two methods were validated against the results from the Monte Carlo method. For the combined mode, some steady-state results were compared with results available in the literature. For the transient situations, results from the two methods were validated against each other. While both the methods were found to give the same results, the CDM was found to be much more economical than the DTM.

ObjectiveGlucocorticoids are known to decrease protein synthesis and conduction velocity of muscle fibers. However, the degree of impairment of muscle protein synthesis and conduction slowing in patients with Cushing's disease remains poorly characterized. Our objective was to investigate whether and to what extent chronic endogenous hypercortisolism could decrease the circulating levels of muscle proteins and modify myoelectric indexes of sarcolemmal excitability and fatigability.DesignA total of ten patients with Cushing's disease and 30 healthy controls matched for age, sex, and body mass index were compared.MethodsBlood sampling and electrophysiological tests on vastus lateralis, vastus medialis, and tibialis anterior muscles were performed.ResultsSerum creatine kinase (CK) and plasma myoglobin were significantly lower in patients with respect to controls (P<0.001 and P<0.05 respectively): the mean relative difference between patients and controls was 48.9% for CK ...

Atrial Fibers. Introduction: Recent studies suggest that atrial fibers in the approaches to the AV node form part of the dual pathways recognized electrophysiologically in patients with AV nodal reentrant tachycardia (AVNRT). Our aim was to determine, by gross dissection, the arrangement of the superficial musculature in the area of the triangle of Koch In normal hearts and in hearts with documented AVNRT. hoping to ascertain anatomic features that might contribute to the debate.Methods and Results: We used blunt dissection to study the architecture of the superficial atrial musculature in 16 autopsied hearts from adults who died of noncardiac disease. A well-defined pattern of architecture of muscle fibers was found in the region of the triangle of Koch, showing marked variations in 7 of the 16 specimens. The relationship of these fibers to the histologically specialized AV node was confirmed by histology in three cases. Two hearts from patients with known AVNRT, treated by ablation in one, were examined further histologically. These sections showed that the site of ablation was well distant from the histologically discrete AV node.Conclusion: The variability in the arrangement of the superficial atrial muscle fibers in the area of the triangle of Koch may be one of the factors influencing the route for impulses entering the AV node. Lesions that ablate nodal reentry are within these atrial fibers rather than the histologically specialized AV node.

We investigate the influence of different magnetic field configurations on the temperature distribution in neutron star crusts. We consider axisymmetric dipolar fields which are either restricted to the stellar crust, "crustal fields", or allowed to penetrate the core, "core fields". By integrating the two-dimensional heat transport equation in the crust, taking into account the classical (Larmor) anisotropy of the heat conductivity, we obtain the crustal temperature distribution, assuming an isothermal core. Including classical and quantum magnetic field effects in the envelope as a boundary condition, we deduce the corresponding surface temperature distributions. We find that core fields result in practically isothermal crusts unless the surface field strength is well above 10 15 G while for crustal fields with surface strength above a few times 10 12 G significant deviations from crustal isothermality occur at core temperatures inferior or equal to 10 8 K. At the stellar surface, the cold equatorial region produced by the suppression of heat transport perpendicular to the field by the Larmor rotation of the electrons in the envelope, present for both core and crustal fields, is significantly extended by that classical suppression at higher densities in the case of crustal fields. This can result, for crustal fields, in two small warm polar regions which will have observational consequences: the neutron star has a small effective thermally emitting area and the X-ray pulse profiles are expected to have a distinctively different shape compared to the case of a neutron star with a core field. These features, when compared with X-ray data on thermal emission of young cooling neutron stars, would provide a first step toward a new way of studying the magnetic flux distribution within a neutron star.