Black hole evaporation in a heat bath as a nonequilibrium process and its final fate

When a black hole evaporates, there arises a net energy flow from black hole into its outside environment (heat bath). The existence of energy flow means that the thermodynamic state of the whole system, which consists of the black hole and the heat bath, is in a nonequilibrium state. Therefore, in order to study the detail of evaporation process, the nonequilibrium effects of the energy flow should be taken into account. Using the nonequilibrium thermodynamics which has been formulated recently, this paper shows the following: (1) Time scale of black hole evaporation in a heat bath becomes shorter than that of the evaporation in an empty space (a situation without heat bath), because a nonequilibrium effect of temperature difference between the black hole and heat bath appears as a strong energy extraction from the black hole by the heat bath. (2) Consequently a huge energy burst (stronger than that of the evaporation in an empty space) arises at the end of semi-classical stage of evaporation. (3) It is suggested that a remnant of Planck size remains after the quantum stage of evaporation in order to guarantee the increase of total entropy of the whole system

Black Hole Evaporation in an Expanding Universe

We calculate the quantum radiation power of black holes which are asymptotic to the Einstein-de Sitter universe at spatial and null infinities. We consider two limiting mass accretion scenarios, no accretion and significant accretion. We find that the radiation power strongly depends on not only the asymptotic condition but also the mass accretion scenario. For the no accretion case, we consider the Einstein-Straus solution, where a black hole of constant mass resides in the dust Friedmann universe. We find negative cosmological correction besides the expected redshift factor. This is given in terms of the cubic root of ratio in size of the black hole to the cosmological horizon, so that it is currently of order $10^{-5} (M/10^{6}M_{\odot})^{1/3} (t/14 {Gyr})^{-1/3}$ but could have been significant at the formation epoch of primordial black holes. Due to the cosmological effects, this black hole has not settled down to an equilibrium state. This cosmological correction may be interpreted in an analogy with the radiation from a moving mirror in a flat spacetime. For the significant accretion case, we consider the Sultana-Dyer solution, where a black hole tends to increase its mass in proportion to the cosmological scale factor. In this model, we find that the radiation power is apparently the same as the Hawking radiation from the Schwarzschild black hole of which mass is that of the growing mass at each moment. Hence, the energy loss rate decreases and tends to vanish as time proceeds. Consequently, the energy loss due to evaporation is insignificant compared to huge mass accretion onto the black hole. Based on this model, we propose a definition of quasi-equilibrium temperature for general conformal stationary black holes.Comment: Accepted for publication in Class.Quant.Grav., 18 pages and 3 figure

Dermoscopy of pigmented lesions on mucocutaneous junction and mucous membrane

Author Posting. Copyright (c) The Authors 2009 This is the author's version of the work. It is posted here for personal use, not for redistribution. The definitive version was published in BRITISH JOURNAL OF DERMATOLOGY, volume: 161, issue: 6, pages:1255-1261. https://doi.org/10.1111/j.1365-2133.2009.09251.xBackground The dermoscopic features of pigmented lesions on the mucocutaneous junction and mucous membrane are different from those on hairy skin. Differentiation between benign lesions and malignant melanomas of these sites is often difficult. Objective To define the dermoscopic patterns of lesions on the mucocutaneous junction and mucous membrane, and assess the applicability of standard dermoscopic algorithms to these lesions. Patients and methods An unselected consecutive series of 40 lesions on the mucocutaneous junction and mucous membrane was studied. All the lesions were imaged using dermoscopy devices, analysed for dermoscopic patterns and scored with algorithms including the ABCD rule, Menzies method, 7-point checklist, 3-point checklist and the CASH algorithm. Results Benign pigmented lesions of the mucocutaneous junction and mucous membrane frequently presented a dotted-globular pattern (25%), a homogeneous pattern (25%), a fish scale-like pattern (18 center dot 8%) and a hyphal pattern (18 center dot 8%), while melanomas of these sites showed a multicomponent pattern (75%) and a homogeneous pattern (25%). The fish scale-like pattern and hyphal pattern were considered to be variants of the ring-like pattern. The sensitivities of the ABCD rule, Menzies method, 7-point checklist, 3-point checklist and CASH algorithm in diagnosing mucosal melanomas were 100%, 100%, 63%, 88% and 100%; and the specificities were 100%, 94%, 100%, 94% and 100%, respectively. Conclusion The ring-like pattern and its variants (fish scale-like pattern and hyphal pattern) are frequently observed as well as the dotted-globular pattern and homogeneous pattern in mucosal melanotic macules. The algorithms for pigmented lesions on hairy skin also apply to those on the mucocutaneous junction and mucous membrane with high sensitivity and specificity.ArticleBRITISH JOURNAL OF DERMATOLOGY. 161(6):1255-1261 (2009)journal articl

On the time dependent Schwarzschild - de Sitter spacetime

An imperfect cosmic fluid with energy flux is analyzed. Even though its energy density $\rho$ is positive, the pressure $p = -\rho$ due to the fact that the metric is asymptotically de Sitter. The kinematical quantities for a nongeodesic congruence are computed. The scalar expansion is time independent but divergent at the singularity $r = 2m$. Far from the central mass $m$ and for a cosmic time $\bar{t} << H^{-1}$, the heat flux $q$ does not depend on Newton's constant $G$.Comment: 8 pages, no figures, Sections 3 and 5 enlarged, one reference adde

Transient myeloproliferative disorder with vesiculopustular eruption: Early smear is useful for quick diagnosis

We report a male infant with Down syndrome who had a transient myeloproliferative disorder associated with skin lesions. He was transferred to a neonatal intensive care unit because of low body weight, fetal edema, disseminated intravascular coagulation, and 10% blast cells in the peripheral blood. On postnatal day (PD) 1, erythema with small papules, vesicles, and pustules appeared on the entire body. A smear preparation from the pustules on PD 2 showed 10% blast cells. A biopsy specimen taken on PD 5 revealed subcorneal pustules containing neutrophils and eosinophils. Genetic analyses detected a somatic mutation (197G>T, Glu295Stop) in exon 2 of GATA-1. On PD 10, the eruptions resolved spontaneously and the population of blast cells in peripheral blood decreased to 1%. The number of blast cells in pustules decreased markedly after three days. Therefore, we recommend that cytologic examination should be performed as early as possible.ArticleJournal of American Academy of Dermatology. 60(5):869-871 (2009)journal articl

Non-equilibrium Landauer Transport Model for Hawking radiation from a Black Hole

We propose that the Hawking radiation energy and entropy flow rates from a black hole can be viewed as a one-dimensional (1D), non-equilibrium Landauer transport process. Support for this viewpoint comes from previous calculations invoking conformal symmetry in the near-horizon region, which give radiation rates that are identical to those of a single 1D quantum channel connected to a thermal reservoir at the Hawking temperature. The Landauer approach shows in a direct way the particle statistics independence of the energy and entropy fluxes of a black hole radiating into vacuum, as well as one near thermal equilibrium with its environment. As an application of the Landauer approach, we show that Hawking radiation gives a net entropy production that is 50% larger than that obtained assuming standard three-dimensional emission into vacuum.Comment: 14 pages, 2 figures, published versio

Terminal Bus Antarmoda Di Isimu (Gorontalo) (Mobilitas Sebagai Pendekatan Desain)

Salah satu prasarana yang dibutuhkan Provinsi Gorontalo yakni prasarana transportasi baik itu transportasi udara, darat, dan laut sehingga dapat menghubungkan Provinsi Gorontalo dengan Provinsi-provinsi lainnya yang ada di Indonesia terlebih khusus yang ada di pulau Sulawesi. Hal-hal inilah yang di jadikan tujuan untuk merancang Terminal Bus Antarmoda di Isimu (Gorontalo) yang dihadirkan dengan tema mobilitas sebagai pendekatan desain yang berlokasi di kabupaten Gorontalo, kecamatan Tibawa. Metode perancangan secara umum dengan melakukan kajian tipologi tentang Terminal Bus Antarmoda, metode kajian tematik tentang Mobilitas sebagai pendekatan desain, metode analisis tapak dan lingkungan, membuat konsep-konsep desain, dan mentransformasikan konsep tersebut menjadi keutuhan desain melalui proses desain generasi dua. Terminal Bus Antarmoda di Isimu (Gorontalo) adalah sebuah prasarana transportasi jalan untuk keperluan menurunkan dan menaikkan penumpang, perpindahan intra dan atau antar moda transportasi serta mengatur kedatangan dan pemberangkatan kendaraan umum yang berada di desa Isimu, Kecamatan Tibawa, Kabupaten Gorontalo, Provinsi Gorontalo. Tema dalam hal ini sebagai acuan dasar dalam perancangan arsitektural, serta sebagai nilai keunikan yang mewarnai keseluruhan hasil rancangan. Tema juga dapat diartikan sebagai koridor dalam pemecahan masalah perancangan, sehingga harus dipertimbangkan faktor asosiasi logis antara tema dan juga objek perancangan. Tema yang digunakan dalam perancangan Terminal Bus Antarmoda di Isimu (Gorontalo) adalah Mobilitas Sebagai Pendekatan Desain. Desain arsitektural Terminal Bus Antarmoda di Isimu (Gorontalo) yang berawal dari imajinasi dan didesain melalui proses analisa-analisa yang dapat mendukung objek ini dihadirkan sehingga menghasilkan suatu wadah yang bisa berfungsi untuk membantu dan mempermudah masyarakat Gorontalo melakukan perjalanan keluar daerah, dan memperlancar hubungkan darat antar wilayah Provinsi yang ada di Pulau Sulawesi

A High Angular Resolution Survey of Massive Stars in Cygnus OB2: Results from the Hubble Space Telescope Fine Guidance Sensors

We present results of a high angular resolution survey of massive OB stars in the Cygnus OB2 association that we conducted with the Fine Guidance Sensor 1R (FGS1r) on the Hubble Space Telescope. FGS1r is able to resolve binary systems with a magnitude difference delta-V < 4 down to separations as small as 0.01 arcsec. The sample includes 58 of the brighter members of Cyg OB2, one of the closest examples of an environment containing a large number of very young and massive stars. We resolved binary companions for 12 targets and confirmed the triple nature of one other target, and we offer evidence of marginally resolved companions for two additional stars. We confirm the binary nature of 11 of these systems from complementary adaptive optics imaging observations. The overall binary frequency in our study is 22% to 26% corresponding to orbital periods ranging from 20 - 20,000 years. When combined with the known short-period spectroscopic binaries, the results supports the hypothesis that the binary fraction among massive stars is > 60%. One of the new discoveries is a companion to the hypergiant star MT 304 = Cyg OB2-12, and future measurements of orbital motion should provide mass estimates for this very luminous star.Comment: accepted for AJ, 84 pages, 61 figure