scholarly journals Asymptotic Stability for an Axis-Symmetric Ohmic Heating Model in Thermal Electricity

2013 ◽  
Vol 2013 ◽  
pp. 1-5
Author(s):  
Anyin Xia ◽  
Mingshu Fan ◽  
Shan Li
Keyword(s):  
Electrical Resistivity ◽  
Asymptotic Behavior ◽  
Ohmic Heating ◽  
The Other ◽  
Dimensionless Temperature ◽  
Nonlocal Term ◽  
Unique Equilibrium ◽  
Heating Model ◽  
Current Flows ◽  
Uniformly Bounded

The asymptotic behavior of the solution for the Dirichlet problem of the parabolic equation with nonlocal termut=urr+ur/r+f(u)/(a+2πb∫01‍f(u)rdr)2,for  0<r<1,  t>0,u1,t=u′(0,t)=0,for  t>0,  ur,0=u0r,  for  0≤r≤1. The model prescribes the dimensionless temperature when the electric current flows through two conductors, subject to a fixed potential difference. One of the electrical resistivity of the axis-symmetric conductor depends on the temperature and the other one remains constant. The main results show that the temperature remains uniformly bounded for the generally decreasing functionf(s), and the global solution of the problem converges asymptotically to the unique equilibrium.

Effect of Elongation on the Electrical Anisotropy of Natural Rubber and SBR Vulcanizates Containing ISAF Carbon Black

1962 ◽  
Vol 35 (2) ◽  
pp. 317-325 ◽  
Author(s):  
R. Chasset ◽  
P. Thirion
Keyword(s):  
Mechanical Properties ◽  
Electrical Resistivity ◽  
Carbon Black ◽  
Natural Rubber ◽  
The Other ◽  
Electrical Anisotropy ◽  
Ohm’S Law ◽  
Carbon Blacks ◽  
Ohm's Law ◽  
Current Flows

Abstract The electrical resistivity of testpieces under different elongations, both parallel and at right-angles to the axis of elongation, was measured for two vulcanizates, i.e. one of natural rubber and the other of SBR, compounded with 20 volume per cent of ISAF black (Vulcan 6). Within the range of validity of Ohm's law, the main results of this study are as follows: a) the resistivities of both vulcanizates increase considerably with elongation, in both directions. b) on the whole, both vulcanizates are electrically anisotropic, since current flows more easily longitudinally than it does transversely. The anisotropy increases at the start with elongation, then becomes practically constant. However, the latter level is much higher with natural rubber, for which it corresponds to an anisotropy of about 1,000 and an elongation of around 150%. For SBR this level is only 20 to 30 and is reached at only 50% elongation. Owing to the complexity of the problem, no interpretation can yet be given for these differences. It will first be necessary to examine other elastomers and carbon blacks. For the time being, it may merely be stated that the electrical anisotropy of natural rubber and SBR reinforced vulcanizates differs as much as their mechanical properties, especially their tearing behavior.

A Multiregion Model with Capital Accumulation and Endogenous Amenities

2007 ◽  
Vol 39 (9) ◽  
pp. 2248-2270 ◽  
Author(s):  
Wei-Bin Zhang
Keyword(s):  
Capital Accumulation ◽  
Comparative Statics ◽  
The Other ◽  
High Rate ◽  
Unique Equilibrium ◽  
Economic Activities ◽  
Technological Differences ◽  
National Output ◽  
Simulation Results ◽  
Wage Disparities

The author develops a multiregional growth model with endogenous amenity and capital accumulation for any number of regions. The simulation results demonstrate that the national dynamics have a unique equilibrium. Comparative statics analysis shows that, if environmental improvement occurs in the technologically advanced (less advanced) region, the national output rises (falls). As a region improves its technology, the other two regions' aggregated output levels fall—not only in relative, but also in absolute, terms. This implies that if any region has a high rate of technological change and the other regions remain technologically stationary, then economic activities will tend to be concentrated in the technologically advancing region. It is also shown that technological differences appear to play only a small role in accounting for spatial wage disparities and endowments.

scholarly journals Flow of Antarctic Bottom Water from the Vema Channel 

2020 ◽  
Author(s):  
Eugene G Morozov ◽  
Dmitry I. Frey ◽  
Roman Y. Tarakanov
Keyword(s):  
Continental Slope ◽  
Water Flow ◽  
North Atlantic ◽  
Bottom Water ◽  
The Other ◽  
Antarctic Bottom Water ◽  
The North ◽  
The North Atlantic ◽  
Current Flows ◽  
Western Wall

Abstract We analyze measurements of bottom currents and thermohaline properties of water north of the Vema Channel with the goal to find pathway continuations of Antarctic Bottom Water flow from the Vema Channel into the Brazil Basin. The analysis is based on CTD/LADCP casts north of the Vema Channel. The flow in the deep Vema Channel consists of two branches. The deepest current flows along the bottom in the center of the channel and the other branch flows above the western wall of the channel. We found two smaller channels of the northern continuation of the deeper bottom flow. These flows become weak and almost disappear at a latitude of 25°30’S. The upper current flows at a depth of 4100-4200 m along the continental slope. We traced this current up to 24°S over a distance exceeding 250 km. This branch transports bottom water that eventually fills the deep basins of the North Atlantic.

Blood Gas Analysis

2011 ◽  
Author(s):  
Patrick Magee ◽  
Mark Tooley
Keyword(s):  
Electrical Potential ◽  
Physical Principle ◽  
Gas Analysis ◽  
The Other ◽  
Potential Difference ◽  
Ion Concentration ◽  
Blood Gas ◽  
Glass Membrane ◽  
Current Flows ◽  
Ph Electrode

A blood gas machine has electrodes to measure pH, pCO2 and pO2 and often measures Hb and some biochemistry as well [King et al. 2000]. Derived values from such a device include O2 saturation, O2 content, bicarbonate, base excess and total CO2. This is the Clarke electrode described in the previous section on gas analysers and is suitable for both respiratory and blood O2 analysis. A pH unit has been defined in Chapter 1 as. In words, this can be described as ‘the negative logarithm, to base ten, of the hydrogen ion concentration’. The physical principle on which the pH electrode is based depends on the fact that when a membrane separates two solutions of different [H+], a potential difference exists across the membrane. In a pH electrode, such a membrane is usually made of glass and the development of a potential difference between the two solutions is thought to be due to the migration of H+ into the glass matrix. If one solution consists of a standard [H+], the pH of the other solution can be estimated by measurement of the potential difference between them. The glass membrane used is selectively permeable to H+. No current flows in this device, which does not wear out, in contrast to the Clark electrode, in which current does flow and that does need periodic replacement. The pH measurement system is shown diagrammatically in Figure 17.1. It consists of two half cells. In one half it has an Ag/AgCl electrode and in the other a Hg/HgCl2 (calomel) electrode. Each electrode maintains a fixed electrical potential. The Ag/AgCl electrode is surrounded by a buffer solution of known pH, surrounded by the pH sensitive glass. Outside the glass membrane is the test solution, usually blood, whose pH is to be measured. It is the potential difference across the glass, between these two solutions, which is variable. The blood or other solution is separated from the calomel electrode by a porous plug and a potassium chloride salt bridge to minimise KCl diffusion. The potential difference across the system is about 60 mV per unit of pH change at 37◦C.

scholarly journals Deterrence with Imperfect Attribution

2020 ◽  
Vol 114 (4) ◽  
pp. 1155-1178 ◽  
Author(s):  
SANDEEP BALIGA ◽  
ETHAN BUENO DE MESQUITA ◽  
ALEXANDER WOLITZKY
Keyword(s):  
Attack Detection ◽  
The Other ◽  
False Alarms ◽  
Unique Equilibrium ◽  
Noisy Signal ◽  
Strategic Complementarity ◽  
Recent Developments

Motivated by recent developments in cyberwarfare, we study deterrence in a world where attacks cannot be perfectly attributed to attackers. In the model, each of $$ n $$ attackers may attack the defender. The defender observes a noisy signal that probabilistically attributes the attack. The defender may retaliate against one or more attackers and wants to retaliate against the guilty attacker only. We note an endogenous strategic complementarity among the attackers: if one attacker becomes more aggressive, that attacker becomes more “suspect” and the other attackers become less suspect, which leads the other attackers to become more aggressive as well. Despite this complementarity, there is a unique equilibrium. We identify types of improvements in attribution that strengthen deterrence—namely, improving attack detection independently of any effect on the identifiability of the attacker, reducing false alarms, or replacing misidentification with non-detection. However, we show that other improvements in attribution can backfire, weakening deterrence—these include detecting more attacks where the attacker is difficult to identify or pursuing too much certainty in attribution. Deterrence is improved if the defender can commit to a retaliatory strategy in advance, but the defender should not always commit to retaliate more after every signal.

scholarly journals Application of Thermoelectric Modules as Renewable Energy Sources

2018 ◽  
Vol 12 (3) ◽  
pp. 151-158
Author(s):  
Ivan Šumiga ◽  
Živko Kondić
Keyword(s):  
Current Flow ◽  
Renewable Energy Sources ◽  
The Other ◽  
Energy Sources ◽  
Experimental Measurements ◽  
Thermoelectric Generators ◽  
Thermoelectric Modules ◽  
Operation And Maintenance ◽  
Flow Through ◽  
Current Flows

Thermoelectric modules are used for heating or cooling if an electric current flows through them. If one side of such a module is heated and the other side is cooled, the outputs show a potential difference that creates the current flow through an enclosed circuit. The paper describes briefly the physical basis of the operation of semiconductor thermoelectric modules and their application for generating electricity as thermoelectric generators. The experimental measurements were made with different available modules of thermoelectric generators. The analysis of obtained results has provided the conclusions about the possibility of their application as sources of electricity. Although the efficiency of thermoelectric modules is still quite low, the latest research reveals the possibility of the use of materials that make modules more efficient. Considering the fact that they do not contain moving parts, they are characterized by reliable, long-lasting work and simple operation and maintenance.

scholarly journals XXVII. On the relative speed of the electric wave through submarine cables of different lengths, and a unit of speed for comparing electric cables by bisecting the electric wave

1863 ◽  
Vol 12 ◽  
pp. 211-216
Keyword(s):  
The Other ◽  
Relative Speed ◽  
Submarine Cable ◽  
Electric Wave ◽  
Retarding Effect ◽  
The Earth ◽  
Current Flows ◽  
Electric Cables ◽  
Submarine Cables ◽  
A Current

The present paper gives the results of some experiments which were undertaken to determine, first, the relative speed of the electric wave through cables of various lengths; secondly, the retarding effect of the iron covering of the cable; and thirdly, methods for the increase of the speed of the electric wave. When a long submarine cable or subterranean wire is connected at one end through a galvanometer to the earth, and the other end is connected with a battery, a current flows through it, deflecting the galvanometer-needle.

EFFECTIVE COMMUNICATIONS MUST BE TWO-WAY1

1969 ◽  
Vol 32 (1) ◽  
pp. 26-27
Author(s):  
L. S. Willson
Keyword(s):  
Outer Space ◽  
Green Light ◽  
Electrical Circuit ◽  
The Other ◽  
Face To Face ◽  
The Subject ◽  
Current Flows ◽  
Communications System

The subject of communications is very much like the weather; everybody talks about it and nobody does anything about it. Today we have the hardware for communicating with each other from any spot on earth and even from outer space. But in our correspondence, our letters, our advertising, and our face-to-face contacts we run into great difficulties because we think too much in terms of one-way communication. A human communications system is very much like an electrical circuit: until the current flows in both directions, there cannot be the green light of understanding. There are three specific areas where we fall down when we try to communicate: (a) words, (b) inferences we make, and (c) appreciation of people. Good two-way communications can exist when we question each other, when we make sure that we both mean the same thing when we use a certain word. And when we stop talking and start listening, the understanding curve goes shooting upward. All of these things can be remembered if we think in terms of the familiar VIP initials: “V” for vocabulary, “I” for inferences, and “P” for people. Two-way communication is after all a “people problem.” If we put ourselves in the other fellow's shoes, if we think less of ourselves and more of him to whom we are communicating, we'll start putting on the green light.

The Bakerian lecture.— On the forms of equipotential curves and surfaces and on lines of flow

1876 ◽  
Vol 24 (164-170) ◽  
pp. 1-32
Keyword(s):  
Cross Section ◽  
Outer Boundary ◽  
The Other ◽  
Curves And Surfaces ◽  
Conducting Wire ◽  
The Wire ◽  
The Cross ◽  
Current Flows ◽  
The One

When any portion of a conducting-wire which joins the two poles of a voltaic battei'y is increased in size, the resistance of the circuit is diminished and a greater current flows through the wire ; and as any increase in the cross section of any portion of the wire causes a corre­sponding increase in the current, it is clear that there is no part of the conducting-wire through which some portion of the current does not flow from the one pole to the other; and the outer boundary of such a wire will be a line of flow. A line of flow is a line drawn in a conductor which indicates at every point of it the direction of the current at that point. A portion of the conductor completely enclosed by lines of flow may be termed a tube of flow.

Sign in / Sign up

Export Citation Format

Share Document