Search Results: 1 - 10 of 100 matches for " "
All listed articles are free for downloading (OA Articles)
Page 1 /100
Display every page Item
Another Way To Realize Maxwell's Demon  [PDF]
Xinyong Fu,Zitao Fu
Physics , 2005,
Abstract: This is another approach to realize Maxwell's "demon" hypothesis. Two Ag-O-Cs thermal electron ejectors, A and B, are settled in a vacuum tube. A non-uniform magnetic field exerted on the tube provides a one-way channel for the thermal electrons. Ejector A, losing electrons, charges positively, while ejector B, getting electrons, charges negatively, resulting in an electric voltage. In flying from A to B, the speed of the electrons decreases, and part of their thermal kinetic energy converts into electric potential energy. Thus, the temperature of the whole electron tube drops down slightly, and that can be compensated by the heat attracted from the ambient air. The device can provide a small but macroscopic power to an external load, violating Kelvin's statement of the second law.
Nature of the Vacuum inside the Color Flux Tube  [PDF]
Ferdinando Gliozzi,Stefano Vinti
Physics , 1996, DOI: 10.1016/S0920-5632(96)00728-1
Abstract: The interior of the color flux tube joining a quark pair can be probed by evaluating the correlator of pair of Polyakov loops in a vacuum modified by another Polyakov pair, in order to check the dual superconductivity conjecture which predicts a deconfined, hot core. We also point out that at the critical point of any 3D gauge theories with a continuous deconfining transition the Svetitsky-Yaffe conjecture provides us with an analytic expression of the Polyakov correlator as a function of the position of the probe inside the flux tube. Both these predictions are compared with numerical results in 3D Z2 gauge model finding complete agreement.
Shot Noise in Schottky's Vacuum Tube  [PDF]
C. Sch?nenberger,S. Oberholzer,E. V. Sukhorukov,H. Grabert
Physics , 2001,
Abstract: In these notes we discuss the origin of shot noise ('Schroteffekt') of vacuum tubes in detail. It will be shown that shot noise observed in vacuum tubes and first described by W. Schottky in 1918 is a purely classical phenomenon. This is in pronounced contrast to shot noise investigated in mesoscopic conductors which is due to quantum mechanical diffraction of electron waves.
Experimental Study on Solar Cooling Tube Using Thermal/Vacuum Emptying Method  [PDF]
Huizhong Zhao,Haibin Liang,Wenzhe Sun,Guoqing Yu,Dan Cao,Jun Ji
Advances in Materials Science and Engineering , 2012, DOI: 10.1155/2012/808210
Abstract: A solar cooling tube using thermal/vacuum emptying method was experimentally studied in this paper. The coefficient of performance (COP) of the solar cooling tube was mostly affected by the vacuum degree of the system. In past research, the thermal vacuum method, using an electric oven and iodine-tungsten lamp to heat up the adsorbent bed and H2O vapor to expel the air from the solar cooling tube, was used to manufacture solar cooling tubes. This paper presents a novel thermal vacuum combined with vacuum pump method allowing an increased vacuum state for producing solar cooling tubes. The following conclusions are reached: the adsorbent bed temperature of solar cooling tube could reaches up to 233°C, and this temperature is sufficient to meet desorption demand; the refrigerator power of a single solar cooling tube varies from 1?W to 12?W; the total supply refrigerating capacity is about 287?kJ; and the COP of this solar cooling tube is about 0.215. 1. Introduction With the improvement of people’s living standard, the demand for air conditioner is increasing. Use of CFCs for refrigeration compression has global warming potential (GWP) and ozone depletion potential (ODP), so their use should be minimized. The energy problem has become a major problem facing human development, and has led to efforts to reduce fossil fuel usage. Solar energy, one of the most abundant resources, has many advantages, most importantly that it is environmentally friendly. This has led to attention from the worldwide research community. Adsorption refrigeration uses nature working pairs as refrigerants and solar energy as a heat resource, so it consumes no fossil fuels during refrigeration process and is environment-friendly. Ferreira Leite et al. [1] presented the characterization and the pre-dimensioning of an adsorption chiller as part of a 20?kW air conditioning central unit for cooling a set of rooms that comprises an area of 110?m2. The adsorption chiller’s expected coefficient of performance (COP) was found to be around 0.6. Khattab [2] presented the description and operation of a simple structure, low cost solar-powered adsorption refrigeration module. Test results showed that a module using bed technique Type 4 and reflector arrangement Type C provided the best performance. Wang et al. [3, 4] used a compound adsorbent of CaCl2 and activated carbon as working pairs and to produce an ice-making test unit for fishing boats. At evaporating temperatures of ?35°C and ?25°C, the cooling powers are 0.89 and 1.18?kW respectively. Clausse [5] explored the possibility to perform
Proposal for the realization of Santilli's comparative test on the gravity of electrons and positrons via a horizontal supercooled vacuum tube  [PDF]
Victor-Otto de Haan
Physics , 2011,
Abstract: A proposal for the realization of Santilli's comparative test of the gravity of electrons and positrons via a horizontal supercooled vacuum tube is described. Principle and requirements are described concerning the sources, vacuum chamber electromagnetic shielding and pressure and position sensitive detector. It is concluded that with current technology the experiment is perfectly feasible.
Vacuum Polarization by a Magnetic Flux Tube at Finite Temperature in the Cosmic String Spacetime  [PDF]
J. Spinelly,E. R. Bezerra de Mello
Physics , 2007, DOI: 10.1142/S0218271809014273
Abstract: In this paper we analyse the effect produced by the temperature in the vacuum polarization associated with charged massless scalar field in the presence of magnetic flux tube in the cosmic string spacetime. Three different configurations of magnetic fields are taken into account: $(i)$ a homogeneous field inside the tube, $(ii)$ a field proportional to $1/r$ and $(iii)$ a cylindrical shell with $\delta$-function. In these three cases, the axis of the infinitely long tube of radius $R$ coincides with the cosmic string. Because the complexity of this analysis in the region inside the tube, we consider the thermal effect in the region outside. In order to develop this analysis, we construct the thermal Green function associated with this system for the three above mentioned situations considering points in the region outside the tube. We explicitly calculate in the high-temperature limit, the thermal average of the field square and the energy-momentum tensor.
Jarzynski Equality with Maxwell's Demon  [PDF]
Takahiro Sagawa,Masahito Ueda
Physics , 2006,
Abstract: We propose a new thermodynamic equality and several inequalities concerning the relationship between work and information for an isothermal process with Maxwell's demon. Our approach is based on the formulation a la Jarzynski of the thermodynamic engine and on the quantum information-theoretic characterization of the demon. The lower bound of each inequality, which is expressed in terms of the information gain by the demon and the accuracy of the demon's measurement, gives the minimum work that can be performed on a single heat bath in an isothermal process. These results are independent of the state of the demon, be it in thermodynamic equilibrium or not.
Electron dynamics inside a vacuum tube diode through linear differential equations  [PDF]
Gabriel Gonzalez,Fco. Javier Gonzalez Orozco
Physics , 2013, DOI: 10.1017/S0022377813001256
Abstract: In this paper we analyze the motion of charged particles in a vacuum tube diode by solving linear differential equations. Our analysis is based on expressing the volume charge density as a function of the current density and coordinates only, while in the usual scheme the volume charge density is expressed as a function of the current density and electrostatic potential. Our approach gives the well known behavior of the classical current density proportional to the three-halves power of the bias potential and inversely proportional to the square of the gap distance between the electrodes, and does not require the solution of the nonlinear differential equation normally associated with the Child-Langmuir formulation.
The Maxwell Demon and Market Efficiency  [PDF]
Roger D. Jones,Sven G. Redsun,Roger E. Frye,Kelly D. Myers
Physics , 2003,
Abstract: This paper addresses two seemingly unrelated problems, (a) What is the entropy and energy accounting in the Maxwell Demon problem? and (b) How can the efficiency of markets be measured? Here we show, in a simple model for the Maxwell Demon, the entropy of the universe increases by an amount eta=0.839995520 in going from a random state to an ordered state and by an amount eta*=2.731382 in going from one sorted state to another sorted state. We calculate the efficiency of an engine driven by the Maxwell sorting process. The efficiency depends only on the temperatures of the particles and of the computer the Demon uses to sort the particles. We also show the approach is general and create a simple model of a stock market in which the Limit Trader plays the role of the Maxwell Demon. We use this model to define and measure market efficiency.
Three problems for the clairvoyant demon  [PDF]
Geoffrey Grimmett
Mathematics , 2009,
Abstract: A number of tricky problems in probability are discussed, having in common one or more infinite sequences of coin tosses, and a representation as a problem in dependent percolation. Three of these problems are of `Winkler' type, that is, they ask about what can be achieved by a clairvoyant demon.
Page 1 /100
Display every page Item

Copyright © 2008-2017 Open Access Library. All rights reserved.