scholarly journals Mpemba Effect- the Effect of Time

2021 ◽  
Author(s):  
Jianan Wang
Keyword(s):  
Gravitational Field ◽  
Black Body ◽  
Black Body Radiation ◽  
Absolute Temperature ◽  
Time Effect ◽  
Gravitational Redshift ◽  
Fourth Power ◽  
Heat Flows ◽  
Nature Of Time ◽  
The Absolute

By analyzing the relation between time and speed, the relation between time and gravitational field, the gravitational redshift of photon and the black-body radiation theorem, the conclusion that time on an object is proportional to the fourth power of the absolute temperature of the object is obtained. Applying the above conclusion about the nature of time, the author analyzes the Mpemba effect and the inverse Mpemba effect, and reaches the following conclusion: the Mpemba effect is the time effect produced when heat flows from objects into space, and the "inverse" Mpemba effect is the time effect produced when heat flows from space into objects.

scholarly journals Mpemba Effect- the Effect of Time

2021 ◽  
Author(s):  
Jianan Wang
Keyword(s):  
Gravitational Field ◽  
Surface Area ◽  
Time Effect ◽  
Light Quantum ◽  
Unit Surface Area ◽  
Heat Flows ◽  
Unit Surface ◽  
Average Wavelength ◽  
Nature Of Time ◽  
The Relationship

This paper draws the following conclusions on the nature of time by analyzing the relationship between time and speed, the relationship between time and gravitational field, the gravitational redshift of the photon, and the black-body radiation theorem: Time on an object is proportional to the amount of energy flowing out (or in) per unit time (observer’s time) per unit surface area of the object. When an object radiates energy outward: t'=μB(T) =μσT 4=μnhν/st Where t’ is the time on the object, μ is a constant, B(T) is the radiosity，the total energy radiated from the unit surface area of the object in unit time (observer’s time), σ is the Stefan-Boltzmann constant, T is the absolute temperature, n is the number of the photons radiated, ν is the average frequency of the photons radiated, s is the surface area of the object and t is the time on the observer. When the object radiates energy outward, the higher the energy density of the space (for example the stronger the gravitational field of the space), the smaller the radiosity B(T) of the object in the space, the longer the average wavelength of the light quantum emitted by the object, the slower the time on the object, the longer the life of the system. When the object radiates energy outward, the faster the object moves relative to the ether, the higher the energy density of the local space in which the object is located, the smaller the radiosity B(T) of the object, the longer the average wavelength of the light quantum radiated by the object, the slower the time on the object, and the longer the life of the system. When the object radiates energy outward, the higher the temperature of the object, the greater the object's radiosity B(T), the shorter the average wavelength of the light quantum radiated by the object, the faster the time on the object, and the shorter the life of the system. Applying the above conclusions about the nature of time, the author analyzes the Mpemba effect and the inverse Mpemba effect, and reaches the following conclusion: the Mpemba effect is the time effect produced when heat flows from objects into space, and the "inverse" Mpemba effect is the time effect produced when heat flows from space into objects.

scholarly journals Absolute Calibration of Stellar Temperatures

1973 ◽  
Vol 54 ◽  
pp. 153-155
Author(s):  
H. Kienle ◽  
D. Labs
Keyword(s):  
Spectral Energy Distribution ◽  
Black Body ◽  
Absolute Temperature ◽  
Spectral Energy ◽  
Absolute Calibration ◽  
Standard Star ◽  
The Absolute ◽  
Stellar Temperatures ◽  
Image Position ◽  
Radiation Laboratory

The scale of effective temperatures Teff is based on observed absolute radiation temperatures Tr, which are defined by Planck's radiation law where TAu designs the absolute temperature of the gold point. A relative scale of radiation temperatures can be derived from spectrophotometric comparisons with a standard star. The absolute calibration of the standard star (α Lyr or Sun) demands a careful comparison with a standard radiation source of well known spectral energy distribution (Black Body or Synchrotron). With ground-based observations atmospheric extinction is to be taken into account; with extraterrestrial observations detectors may be used which are absolutely calibrated in a radiation laboratory under space conditions.

scholarly journals A determination of the radiation constant

1913 ◽  
Vol 88 (600) ◽  
pp. 49-60 ◽  
Keyword(s):  
Absolute Temperature ◽  
Absolute Zero ◽  
Fourth Power ◽  
Net Radiation ◽  
A Value ◽  
The Absolute ◽  
Boltzmann Law

According to the Stefan-Boltzmann law, the radiation emitted by a full radiator is surroundings at a temperature of absolute zero is proportional to the fourth power of the absolute temperature of the radiator, or R = σθ 4 , where R = radiation in ergs per cm 2 . per sec., θ = absolute temperature of radiator, σ = radiation constant. If the radiator is in surroundings at absolute temperature θ 1 , which are themselves full radiators, then R´ = R θ -R θ 1 = σ( θ 4 - θ 1 4 ), where R´ is the net radiation. The first important determination of the radiation constant is due to Kurlbaum, who obtained a value 5·33 × 10 -5 erg/sec. cm. 2 deg. 4 , recently corrected to 5·45 × 10 -5 erg/sec. cm. 2 deg. 4 Later investigations give results varying considerably from Kurlbaum's and from one another, and, on the whole, they indicate that Kurlbaum's value is too low. Some determinations are given in the following table:—

scholarly journals A new method of determining the radiation constant

1912 ◽  
Vol 86 (585) ◽  
pp. 180-196 ◽  
Keyword(s):  
Black Body ◽  
Absolute Temperature ◽  
Absolute Zero ◽  
New Method ◽  
Platinum Black ◽  
Main Current ◽  
First Case ◽  
Black Surface ◽  
The Absolute

According to stefan's law the rate of radiation of energy from a full radiator in surroundings at a temperature of absolute zero is σ θ 4 ergs per cm. 2 per sec., where θ is the absolute temperature of the radiator. If the radiator be in surroundings which are themselves full radiators, but at absolute temperature θ 1 , the rate of loss of energy by radiation is taken to be σ( θ 4 - θ 1 4 ). The classical determination of the constant σ is due to Kurlbaum, who used a surface bolometer with a platinum-black surface. The rise of temperature of the bolometer when exposed to the radiation from an approximately full radiator or "black body" was observed. The radiation was then cut off, and an equal rise of temperature was produced by increasing the main current in the bolometer. It was assumed that the energy received per second from the radiator in the first case was equal to the energy received per second from the increase of current in the second ease. The resulting value of σ was 5·33 x 10 -5 ergs per cm. 2 per sec. per deg. 4 , or 5·33 x 10 -12 watts per cm. 2 per deg. 4 .

Emissivity Caracterization in Stainless Steels Alloys for Application in Hidroeletric Turbines

2015 ◽  
Vol 719-720 ◽  
pp. 3-12 ◽  
Author(s):  
Matheus Tabata Santos ◽  
Palloma Vieira Muterlle ◽  
Guilherme Caribé de Carvalho
Keyword(s):  
Gas Flow ◽  
Sample Surface ◽  
Black Body ◽  
Absolute Temperature ◽  
Small Sample ◽  
Experimental Methodology ◽  
Fourth Power ◽  
Thermographic Camera ◽  
Materials Used ◽  
The University

Emissivity is the ratio between the radiant hemispherical power emitted by a real body, at an absolute temperature, and the radiant hemispherical power emitted by a black body at the same temperature. The energy emitted is proportional to the fourth power of the object ́s temperature. Emissivity may vary from 0 (reflected by a mirror) to 1.0 (black body theory). Studies are being carried out at the University of Brasilia to investigate the microstructural behavior of materials used in the repairing of hydroelectric turbines, after several thermal cycles of welding. These studies use thermographic techniques for monitoring the temperature and require that the correct emissivity value for specific materials and surface conditions are used in order to guaranty that the temperatures reported by the radiometric sensors are consistent with the actual temperatures. This study aims to validate an experimental methodology for evaluating the emissivity of the steel ASTM A 743 CA6NM and the AWS 410 NiMo as deposited by a GMAW process at temperatures ranging from 100oC to 1000oC. The experiment consists of heating a small sample of the material with an oxyacetylene torch while a thermocouple, welded on surface of the sample, an infrared sensor and a thermographic camera monitor the surface temperature. During the heating and the cooling process, the sample surface is protected from the air by an argon gas flow directed towards the visualized area. Results consistent with the reported in the literature for similar materials were attained and curves of the emissivity “versus” temperature for the tested materials were produced, providing a basis for proper thermographic temperature monitoring.

scholarly journals Some phenomena connected with the transfer of heat by radiation and turbulence in the lower atmosphere

1930 ◽  
Vol 130 (812) ◽  
pp. 98-104 ◽  
Keyword(s):  
Black Body ◽  
Black Body Radiation ◽  
Mean Value ◽  
Absolute Temperature ◽  
Lower Atmosphere ◽  
Lapse Rate ◽  
A Value ◽  
Radiative Diffusion ◽  
The Mean ◽  
Very High

One of the most outstanding facts of observation of the distribution of temperature in the atmosphere is the constancy of the mean lapse-rate of temperature at all heights within the troposphere and in all latitudes. The variation about the mean value, which is roughly one-half of the dry adiabatic lapse-rate, is very slight at all heights greater than a few hundred metres above the ground, but in the layer nearest the ground the extent of the variation is very considerable. At night, and particularly during clear nights in winter, the sign of the lapse-rate in the lowest layer is changed, and the temperature increases with height instead of decreasing. On sunny summer afternoons the lapse-rate in the lowest layers attains very high values, the change of temperature from 1/2 metre to 1 metre above the ground amounting to the equivalent of 100 to 200 times the dry adiabatic lapse-rate. Observations in the layers still nearer to the ground are not yet available, but the nature of the values hitherto observed suggests that the lapse-rate increases in a marked manner as we approach the surface. This raises a very natural question. Is there any limit to the lapse-rate which physically capable of foundation in the atmosphere immediately above the ground? In an earlier paper, I have shown that the outward flux of heat (W-radiation) by radiation can be represented by — k ∂͞T/∂͞z calories/cm. 2 /min., where k is 115/ p m at a temperature of 275° A., p w being the vapour pressure in millibars, and T representing the absolute temperature at a height z above the ground. The average amount of incoming radiation which has to be disposed of is given ( loc. cit .) as 0∙275 calories/cm. 2 /min. This, however, is the average over all latitudes, and over day and night, and is too low a value for our present purposes. We shall adopt instead an amount equal to black body radiation at 280° A. amounting to 0∙509 calories/cm. 2 /min. Of this, an amount 0∙290 calories/cm. 2 /min. leaves the ground as W-radiation. These figures would roughly correspond with afternoon sunshine in the British Isles. If we assume the temperature gradient in the layer near the ground to be ∂͞T/∂͞z, then it has been shown ( loc. cit .) that in this layer the amount of W-radiation transported outward by radiative diffusion is —1/2 k ∂͞T/∂͞z. If the lapse-rate has the value given by the equation.

scholarly journals Understanding entropy

2021 ◽  
Author(s):  
Peter G. Nelson
Keyword(s):  
Absolute Temperature ◽  
The State ◽  
Heat Flows ◽  
Macroscopic Property ◽  
Heat Engines ◽  
Statistical Mechanical ◽  
Mechanical Interpretation ◽  
The Absolute ◽  
Isolated Systems ◽  
System Entropy

AbstractA new way of understanding entropy as a macroscopic property is presented. This is based on the fact that heat flows from a hot body to a cold one even when the hot one is smaller and has less energy. A quantity that determines the direction of flow is shown to be the increment of heat gained (q) divided by the absolute temperature (T). The same quantity is shown to determine the direction of other processes taking place in isolated systems provided that q is determined by the state (s) of the system. Entropy emerges as the potent energy of a system [Σ(qs/T)], the potency being determined by 1/T. This is shown to tie in with the statistical mechanical interpretation of entropy. The treatment is shorter than the traditional one based on heat engines.

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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