124 research outputs found

    Heat Transfer Behavior and Physiological Effects of Living Human Skin under Local Radiative Thermal Stimulation

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    In order to develop a moxibustion treatment device that can heat appropriately by radiation while lowering the risk of burning by the moxa, a local radiative heating device for skin was fabricated and the unsteady response of the skin surface and internal temperature during infrared radiative heating were evaluated based on subjective experiments and numerical analysis. Because it was necessary to perform non-contact temperature measurements of the heated surface to control the heat, methods of evaluating and correcting the impact on measurement precision were studied. The study clarified that as skin was heated, the skin surface temperature rose, and the blood flow speed around the heated part increased. A local thermal sensation corresponded to the increase. Absorption of radiation by skin occurred only near the surface, so it was concluded that a useful way to effectively heat skin, was to set a certain temperature as the upper limit of the surface temperature, and lower the heat when this temperature has been reached, wait for the heat to penetrate more deeply, then restart heating

    Uniting the Quiescent Emission and Burst Spectra of Magnetar Candidates

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    Spectral studies of quiescent emission and bursts of magnetar candidates using XMM-Newton, Chandra and Swift data are presented. Spectra of both the quiescent emission and the bursts for most magnetar candidates are reproduced by a photoelectrically absorbed two blackbody function (2BB). There is a strong correlation between lower and higher temperatures of 2BB (kT_LT and kT_HT) for the magnetar candidates of which the spectra are well reproduced by 2BB. In addition, a square of radius for kT_T (R_LT^2) is well correlated with a square of radius for kT_HT (R_HT^2). A ratio kT_LT/kT_HT ~ 0.4 is nearly constant irrespective of objects and/or emission types (i.e., the quiescent emission and the bursts). This would imply a common emission mechanism among the magnetar candidates. The relation between the quiescent emission and the bursts might be analogous to a relation between microflares and solar flares of the sun. Three AXPs (4U 0142+614, 1RXS J170849.0-400910 and 1E 2259+586) seem to have an excess above ~7 keV which well agrees with a non-thermal hard component discovered by INTEGRAL.Comment: 17 pages, 5 figures, 12 tables, Accepted for publication in PAS

    Conduction-Radiation Property of Ceramic and Graphite Fiber Thermal Insulation Mat

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    The thermal conductivities for four typical kinds of heat resisting fibrous thermal insulation mats were obtained by the steady state parallel plates method in a vacuum condition. These experimental results were correlated by a combined conduction and radiation heat transfer model to determine the conduction thermal conductivity and the extinction coefficient which govern the heat transfer in the layer of fibrous insulating material. On the basis of these values, a new simple method was proposed to estimate the thermal conductivities of the four materials as a function of the bulk density and the mean temperature in the insulation layer

    Non-Equilibrium Ionization States of GRB Environments

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    Iron spectral features are thought to be the best tracer of a progenitor of gamma-ray bursts (GRBs). The detections of spectral features such as an iron line and/or a Radiative Recombination edge and Continuum (RRC) were reported in four X-ray afterglows of GRBs. However their properties were different each other burst by burst. For example, Chandra observation of GRB 991216 reported both the strong H-like iron line together with its RRC. On the contrary, Yoshida et al. (2001) report only a detection of the strong RRC in GRB 970828 with ASCA. Since it is difficult to produce the strong RRC, we have to consider special condition for the line and/or the RRC forming region. In this paper, we point out a possibility of a ``non-equilibrium ionization state'' for the line and the RRC forming region.Comment: 10pages, 2figures. Accepted for ApJL. This is a companion paper by A.Yoshida et. a

    Measurement of saturated solubilities and diffusion coefficients of pure gases to mineral oil

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    The present paper deals with measurements of the diffusion coefficients as well as the saturated solubilities of single component gases such as N(2), O(2) and CO(2) to a mineral oil. The method to determine the diffusivity is based upon measuring the pressure changes caused by the one-dimensional diffusion between the gas and the oil enclosed in an airtight container. For N(2) and O(2) the profiles of the measured pressure changes agree well with those predicted by diffusion theory, whereas that is not the case with CO(2). Although the reason why CO(2) does not seem to obey diffusion theory has yet to be studied, it may suggest the possibility that the diffusion coefficient varies with the pressure, considering that the range of pressure change in the diffusivity measurement was much obtained by this method fell within ±30% around the average. Moreover the solubility measurements have made clear that Henry's law holds true between the three pure gases and the oils tested, and that O(2) and CO(2) dissolve into the oil approximately two and ten times more, respectively, than N(2)

    Combined Spectral and Timing Analysis of the Black Hole Candidate MAXI J1659-152 Discovered by MAXI and Swift

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    We report on X-ray spectral and timing results of the new black hole candidate (BHC) MAXI J1659-152 with the orbital period of 2.41 hours (shortest among BHCs) in the 2010 outburst from 65 Rossi X-ray Timing Explorer (RXTE) observations and 8 simultaneous Swift and RXTE observations. According to the definitions of the spectral states in Remillard & McClintock (2006), most of the observations have been classified into the intermediate state. All the X-ray broadband spectra can be modeled by a multi-color disk plus a power-law with an exponential cutoff or a multi-color disk plus a Comptonization component. During the initial phase of the outburst, a high energy cutoff was visible at 30-40 keV. The innermost radius of the disk gradually decreased by a factor of more than 3 from the onset of the outburst and reached a constant value of 35 d_10 cos i^-1/2 km, where d_10 is the distance in units of 10 kpc and ii is the inclination. The type-C quasi-periodic oscillation (QPO) frequency varied from 1.6 Hz to 7.3 Hz in association with a change of the innermost radius, while the innermost radius remained constant during the type-B QPO detections at 1.6-4.1 Hz. Hence, we suggest that the origin of the type-B QPOs is different from that of type-C QPOs, the latter of which would originate from the disk truncation radius. Assuming the constant innermost radius in the latter phase of the outburst as the innermost stable circular orbit, the black hole mass in MAXI J1659-152 is estimated to be 3.6-8.0 M_solar for a distance of 5.3-8.6 kpc and an inclination angle of 60-75 degrees.Comment: 27 pages, 14 figures, accepted for publication in PAS

    Luminosity dependence of the electron temperature in the bright hard state of the black hole candidate GX 339--4

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    We have analyzed 200 Rossi X-ray Timing Explorer observations of the black hole candidate GX 339--4, all from the bright hard state periods between 1996 and 2005. Purpose of our study is to investigate the radiation mechanisms in the hard state of GX 339--4. The broadband 3--200 keV spectra were successfully modeled by a simple analytic model, power--law with an exponential cut-off modified with a smeared edge. The obtained energy cut-off (EcutE_{\rm{cut}}) was distributed over 50--200 keV, and the photon index over 1.4--1.7. We found a clear anti-correlation (EcutL0.70±0.06E_{\rm{cut}} \propto L^{-0.70\pm0.06}) between the X-ray luminosity (LL) in 2--200 keV and EcutE_{\rm{cut}}, when LL is larger than 7×10377 \times 10^{37} erg s1^{-1} (assuming a distance of 8 kpc), while EcutE_{\rm{cut}} is roughly constant at around 200 keV when LL is smaller than 7×10377 \times 10^{37} erg s1^{-1}. This anti-correlation remained unchanged by adopting a more physical thermal Comptonization model, which resulted in the anti-correlation that can be expressed as kTeL0.24±0.06kT_{\rm{e}} \propto L^{-0.24\pm0.06}. These anti-correlations can be quantitatively explained by a picture in which the energy-flow rate from protons to electrons balances with the inverse Compton cooling.Comment: Accepted by PASJ. 15 pages, 8 figure
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