The Relations Between Entropy and Energy of Black-Body Radiation

2006 ◽  
Author(s):  
Richard A. Gaggioli
Keyword(s):  
Internal Energy ◽  
Transfer Rate ◽  
Unit Volume ◽  
Energy Content ◽  
Black Body ◽  
Black Body Radiation ◽  
The Other ◽  
Proportionality Factor ◽  
Entropy Transfer ◽  
The Difference

The entropy content of electromagnetic ("black-body") radiation at equilibrium in an enclosure is represented, on a per unit volume basis, by s = [4/3]aT3 and the internal energy content by u = aT4, so s = [4/3]u/T. The entropy transfer rate Sτ associated with emission from the radiation is related to the internal energy trans-fer rate Q by Sτ = Q/T. In both cases, content and flux, the entropy is proportional to energy divided by temperature. But, in one case the proportionality factor is [4/3] and in the other it is unity. The question has been raised, "Why, this difference?" The following develop-ment explains the source of the difference.

Effect of Surface Roughness on the Total Hemispherical and Specular Reflectance of Metallic Surfaces

1964 ◽  
Vol 86 (2) ◽  
pp. 193-199 ◽  
Author(s):  
R. C. Birkebak ◽  
E. M. Sparrow ◽  
E. R. G. Eckert ◽  
J. W. Ramsey
Keyword(s):  
Surface Roughness ◽  
Black Body ◽  
Black Body Radiation ◽  
The Other ◽  
Angle Of Incidence ◽  
Metallic Surfaces ◽  
Specular Reflectance ◽  
Other Hand ◽  
Hemispherical Reflectance ◽  
Effect Of Surface

Measurements have been made of the hemispherical and specular reflectance of metallic surfaces of controlled roughness. The surfaces, which were ground nickel rectangles, were irradiated at various angles of incidence by a beam of black-body radiation, the temperature of which was also varied. The instrumentation which was devised to perform the experiments is described. The measurements show that beyond a certain surface roughness, the hemispherical reflectance is virtually independent of further increases in roughness. On the other hand, the specular reflectance decreases steadily with increasing roughness. Additionally, the hemispherical reflectance is found to be quite insensitive to the angle of incidence, while the specular reflectance increases with angle of incidence for the rougher surfaces.

The Propagation of Electromagnetic Waves in a Refracting Medium in a Magnetic Field

1931 ◽  
Vol 27 (1) ◽  
pp. 143-162 ◽  
Author(s):  
D. R. Hartree
Keyword(s):  
Magnetic Field ◽  
Dielectric Constant ◽  
Electromagnetic Waves ◽  
Unit Volume ◽  
The Other ◽  
Stratified Medium ◽  
Dielectric Tensor ◽  
Present Treatment ◽  
Induced Dipole ◽  
The Difference

The equations of propagation of electromagnetic waves, simple harmonic in time, in an optically anisotropic stratified medium are obtained from the treatment of the refracted wave as the resultant of the incident wave and wavelets scattered by the elements of volume of the medium, and are reduced to a simple form.The primitive property of the medium, from which the other optical properties are derived, is the scattering tensor, relating the induced dipole moment per unit volume to the applied electric field.The relation between the dielectric tensor (corresponding to the dielectric constant of an isotropic medium) and the scattering tensor is obtained.A medium consisting of classical oscillators in an external magnetic field is then considered, the scattering tensor and dielectric tensor are evaluated for such a medium, and finally a formula for the refractive index is obtained.For an ionised medium the formula differs from that obtained by Goldstein; the difference is due to the inclusion in the present treatment of a term omitted by Goldstein; the significance of this term is discussed, and its inclusion justified.Taking this term into account makes an important difference to the properties of the medium for long waves; an example is given.

scholarly journals Linearization of Nongray Radiation Exchange: The Internal Fractional Function Reconsidered

2019 ◽  
Vol 141 (5) ◽  
Author(s):  
John H. Lienhard V
Keyword(s):  
Black Body ◽  
Black Body Radiation ◽  
Analytical Approximation ◽  
New Approach ◽  
Radiation Exchange ◽  
Wide Range ◽  
The Difference ◽  
Exact Calculations ◽  
Improved Accuracy ◽  
Fractional Function

The radiation fractional function is the fraction of black body radiation below a given value of λT. Edwards and others have distinguished between the traditional, or “external,” radiation fractional function and an “internal” radiation fractional function. The latter is used for linearization of net radiation from a nongray surface when the temperature of an effectively black environment is not far from the surface's temperature, without calculating a separate total absorptivity. This paper examines the analytical approximation involved in the internal fractional function, with results given in terms of the incomplete zeta function. A rigorous upper bound on the difference between the external and internal emissivity is obtained. Calculations using the internal emissivity are compared to exact calculations for several models and materials. A new approach to calculating the internal emissivity is developed, yielding vastly improved accuracy over a wide range of temperature differences. The internal fractional function should be used for evaluating radiation thermal resistances, in particular.

scholarly journals Non-Gray Radiation Exchange: The Internal Fractional Function Reconsidered

2018 ◽  
Author(s):  
John H. Lienhard
Keyword(s):  
Black Body ◽  
Black Body Radiation ◽  
Analytical Approximation ◽  
Radiation Exchange ◽  
Wide Range ◽  
The Difference ◽  
Exact Calculations ◽  
Simplified Calculation ◽  
Improved Accuracy ◽  
Fractional Function

The radiation fractional function is the fraction of black body radiation below a given value of λT. Edwards and others have distinguished between the traditional, or “external”, radiation fractional function and an “internal” radiation fractional function. The latter is used for simplified calculation of net radiation from a non-gray surface when the temperature of an effectively black source is not far from the surface’s temperature, without calculating a separate total absorptivity. This paper examines the analytical approximation involved in the internal fractional function, with results given in terms of the incomplete zeta function. A rigorous upper bound on the difference between the external and internal emissivity is obtained. Calculations using the internal emissivity are compared to exact calculations for several models and materials. A new approach to calculating the internal emissivity is developed, yielding vastly improved accuracy over a wide range of temperature differences. The internal fractional function can be useful for certain simplified calculations.

Enhancement of ADP-induced Platelet Aggregation by Adrenaline in Vivo and Its Prevention

1973 ◽  
Vol 29 (02) ◽  
pp. 490-498 ◽  
Author(s):  
Hiroh Yamazaki ◽  
Itsuro Kobayashi ◽  
Tadahiro Sano ◽  
Takio Shimamoto
Keyword(s):  
Platelet Count ◽  
Platelet Aggregation ◽  
Platelet Rich Plasma ◽  
The Other ◽  
Endothelial Surface ◽  
Important Interaction ◽  
Blood Coagulability ◽  
The Difference

SummaryThe authors previously reported a transient decrease in adhesive platelet count and an enhancement of blood coagulability after administration of a small amount of adrenaline (0.1-1 µg per Kg, i. v.) in man and rabbit. In such circumstances, the sensitivity of platelets to aggregation induced by ADP was studied by an optical density method. Five minutes after i. v. injection of 1 µg per Kg of adrenaline in 10 rabbits, intensity of platelet aggregation increased to 115.1 ± 4.9% (mean ± S. E.) by 10∼5 molar, 121.8 ± 7.8% by 3 × 10-6 molar and 129.4 ± 12.8% of the value before the injection by 10”6 molar ADP. The difference was statistically significant (P<0.01-0.05). The above change was not observed in each group of rabbits injected with saline, 1 µg per Kg of 1-noradrenaline or 0.1 and 10 µg per Kg of adrenaline. Also, it was prevented by oral administration of 10 mg per Kg of phenoxybenzamine or propranolol or aspirin or pyridinolcarbamate 3 hours before the challenge. On the other hand, the enhancement of ADP-induced platelet aggregation was not observed in vitro, when 10-5 or 3 × 10-6 molar and 129.4 ± 12.8% of the value before 10∼6 molar ADP was added to citrated platelet rich plasma (CPRP) of rabbit after incubation at 37°C for 30 second with 0.01, 0.1, 1, 10 or 100 µg per ml of adrenaline or noradrenaline. These results suggest an important interaction between endothelial surface and platelets in connection with the enhancement of ADP-induced platelet aggregation by adrenaline in vivo.

Comparative Study of Size, Total Protein, Fibrinogen and 5-HT Content of Human and Canine Platelet Density Subpopulations

1986 ◽  
Vol 56 (03) ◽  
pp. 288-292 ◽  
Author(s):  
Diego Mezzano ◽  
Eduardo Aranda ◽  
Arnaldo Foradori
Keyword(s):  
Comparative Study ◽  
Protein Content ◽  
Cell Density ◽  
Total Protein ◽  
Unit Volume ◽  
Low Density ◽  
Dense Bodies ◽  
Artifactual Changes ◽  
Platelet Release ◽  
The Difference

SummaryThe size, total protein, fibrinogen and 5-HT content were evaluated in density subpopulations of human and canine platelets fractionated in linear arabinogalactan gradients. The methodology was assessed to ascertain that platelet separation was by density and to discard artifactual changes and platelet release during the procedure. EDTA or PGEi increased the size of human PRP-platelets, but not of dog platelets. In humans, high density (HD) platelets were 1.26 times larger and contained 1.88 times more fibrinogen, 2.23 times more 5-HT and 1.37 times more protein than low density (LD) platelets; in dogs, these density cohorts did not differ in protein content, but LD platelets were 1.29 times larger and had 1.33 times more fibrinogen and 5-HT than HD platelets. These findings suggest that cell density is mostly dependent on the protein content per unit volume of platelets (and not on dense bodies). The differences in fibrinogen and 5-HT content between HD and LD cohorts in humans and dogs may be related to platelet age. The difference in volume between HD and LD platelets in dogs is of uncertain interpretation.

Energy Approximation

2017 ◽  
Author(s):  
Philip Isett
Keyword(s):  
Main Lemma ◽  
The Other ◽  
Coarse Scale ◽  
Continuous Solutions ◽  
Material Derivative ◽  
Energy Variation ◽  
Energy Approximation ◽  
The Difference ◽  
Derivatives Of

This chapter presents the equations and calculations for energy approximation. It establishes the estimates (261) and (262) of the Main Lemma (10.1) for continuous solutions; these estimates state that we are able to accurately prescribe the energy that the correction adds to the solution, as well as bound the difference between the time derivatives of these two quantities. The chapter also introduces the proposition for prescribing energy, followed by the relevant computations. Each integral contributing to the other term can be estimated. Another proposition for estimating control over the rate of energy variation is given. Finally, the coarse scale material derivative is considered.

Pengaruh Unsur Budaya Lokal dalam Ungkapan Berbahasa Perancis

Metahumaniora ◽  
2017 ◽  
Vol 7 (3) ◽  
pp. 378
Author(s):  
Vincentia Tri Handayani
Keyword(s):  
Mental Representation ◽  
Cultural Context ◽  
Oral Tradition ◽  
Minimal Element ◽  
The Other ◽  
Local Culture ◽  
Community Groups ◽  
Cultural Community ◽  
The Difference ◽  
Complex Words

AbstrakFolklor yang menghasilkan tradisi lisan merupakan perwujudan budaya yang lahirdari pengalaman kelompok masyarakat. Salah satu bentuk tradisi lisan adalah ungkapan yangmengandung unsur budaya lokal dalam konstruksinya yang tidak dimiliki budaya lainnya.Ungkapan idiomatis memberikan warna pada bahasa melalui penggambaran mental. Dalambahasa Perancis, ungkapan dapat berupa locution dan expression. Perbedaan motif acuansuatu ungkapan dapat terlihat dari pengaruh budaya masyarakat pengguna bahasa. Sebuahleksem tidak selalu didefinisikan melalui unsur minimal, tidak juga melalui kata-kata,baik kata dasar atau kata kompleks, namun dapat melalui kata-kata beku yang maknanyatetap. Hubungan analogis dari makna tambahan yang ada pada suatu leksem muncul dariidentifikasi semem yang sama. Semem tersebut mengarah pada term yang diasosiasikan danyang diperkaya melalui konteks (dalam ungkapan berhubungan dengan konteks budaya).Kata kunci: folklor, ungkapan, struktur, makna idiomatis, kebudayaanAbstractFolklore which produces the oral tradition is a cultural manifestation born out theexperience of community groups. One form of the oral tradition is a phrase that containsthe elements of local culture in its construction that is not owned the other culture. Theidiomatic phrase gives the color to the language through the mental representation. InFrench, the expression can consist of locution and expression. The difference motivesreference of an expression can be seen from the influence of the cultural community thelanguage users. A lexeme is not always defined through a minimal element, nor throughwords, either basic or complex words, but can be through the frost words whose meaningsare fixed. The analogical connection of the additional meanings is on a lexeme arises fromthe identification of the same meaning. The meaning ‘semem’ leads to the associated termsand which are enriched through the context (in idiom related to the cultural context).Keywords : folklore, idioms, structure, idiom meaning, cultureI PENDAHULUAN

The Physical World

2017 ◽  
Author(s):  
Nicholas Manton ◽  
Nicholas Mee
Keyword(s):  
Quantum Mechanics ◽  
Particle Physics ◽  
Variational Principles ◽  
Black Body ◽  
Black Body Radiation ◽  
Physical World ◽  
Atomic Scale ◽  
Solid State Physics ◽  
Least Action ◽  
Dimensional Spacetime

The book is an inspirational survey of fundamental physics, emphasizing the use of variational principles. Chapter 1 presents introductory ideas, including the principle of least action, vectors and partial differentiation. Chapter 2 covers Newtonian dynamics and the motion of mutually gravitating bodies. Chapter 3 is about electromagnetic fields as described by Maxwell’s equations. Chapter 4 is about special relativity, which unifies space and time into 4-dimensional spacetime. Chapter 5 introduces the mathematics of curved space, leading to Chapter 6 covering general relativity and its remarkable consequences, such as the existence of black holes. Chapters 7 and 8 present quantum mechanics, essential for understanding atomic-scale phenomena. Chapter 9 uses quantum mechanics to explain the fundamental principles of chemistry and solid state physics. Chapter 10 is about thermodynamics, which is built around the concepts of temperature and entropy. Various applications are discussed, including the analysis of black body radiation that led to the quantum revolution. Chapter 11 surveys the atomic nucleus, its properties and applications. Chapter 12 explores particle physics, the Standard Model and the Higgs mechanism, with a short introduction to quantum field theory. Chapter 13 is about the structure and evolution of stars and brings together material from many of the earlier chapters. Chapter 14 on cosmology describes the structure and evolution of the universe as a whole. Finally, Chapter 15 discusses remaining problems at the frontiers of physics, such as the interpretation of quantum mechanics, and the ultimate nature of particles. Some speculative ideas are explored, such as supersymmetry, solitons and string theory.

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