General Relation for Field Admittance and Intensity Field admittance

2008 ◽  
pp. 11-12
Keyword(s):  
General Relation ◽  
Intensity Field

Air movement and heat loss from sheep. II. Thermal insulation of fleece in wind

1980 ◽  
Vol 209 (1175) ◽  
pp. 209-217 ◽  
Keyword(s):  
Thermal Diffusivity ◽  
Heat Loss ◽  
Thermal Insulation ◽  
General Relation ◽  
Windward Side ◽  
Leeward Side ◽  
Sensible Heat ◽  
Bulk Resistance ◽  
Air Movement ◽  
Dimensionless Constant

Penetration of an animal’s coat by wind reduces its thermal insulation and increases heat loss to the environment. From studies of the sensible heat loss from a life-sized model sheep covered with fleece, the average fleece resistance r¯ f (s cm -1 ) was related to windspeed u (m s -1 ) by 1/ r¯ f ( u ) = l/ r¯ f (0) + cu , where c is a dimensionless constant. As c is expected to be inversely proportional to coat depth Î , the more general relation k¯ ( u ) = k¯ (0) + c'u was evaluated, where k¯ = Î / r¯ f is the thermal diffusivity (cm 2 s -1 ) of the fleece and c' = cÎ is another constant (cm). The orientation of the model to the wind had little effect on the bulk resistance of the fleece, but the resistance on the windward side was substantially lower than on the leeward side.

ON THE CALCULATION OF THE HEAT CAPACITY IN PATH INTEGRAL MONTE CARLO SIMULATIONS

1992 ◽  
Vol 03 (02) ◽  
pp. 337-346 ◽  
Author(s):  
D. MARX ◽  
P. NIELABA ◽  
K. BINDER
Keyword(s):  
Heat Capacity ◽  
Monte Carlo ◽  
Monte Carlo Simulations ◽  
Path Integral ◽  
General Relation ◽  
Absolute Magnitude ◽  
Computational Effort ◽  
Imaginary Time ◽  
Time Dimension ◽  
Path Integral Monte Carlo

In Path Integral Monte Carlo simulations the systems partition function is mapped to an equivalent classical one at the expense of a temperature-dependent Hamiltonian with an additional imaginary time dimension. As a consequence the standard relation linking the heat capacity Cv to the energy fluctuations, <E2>−<E>2, which is useful in standard classical problems with temperature-independent Hamiltonian, becomes invalid. Instead, it gets replaced by the general relation [Formula: see text] for the intensive heat capacity estimator; β being the inverse temperature and the subscript P indicates the P-fold discretization in the imaginary time direction. This heatcapacity estimator has the advantage of being based directly on the energy estimatorand thus requires no extra computational effort and is suited for extensive phase diagramstudies. As an example, numerical results are presented for a two-dimensional fluid withinternal magnetic quantum degrees of freedom. We discuss in detail origin and consequences of the excess term. Due to the subtraction of two relatively large contributions ofsimilar absolute magnitude a large statistical effort would be necessary for very accurateheat capacity estimates.

The Minimum Separation Work for Desalination Processes

1999 ◽  
Author(s):  
Yunus Çerçi ◽  
Yunus A. Çengel ◽  
Byard Wood
Keyword(s):  
Fresh Water ◽  
Saline Water ◽  
General Relation ◽  
Second Law Of Thermodynamics ◽  
Recovery Ratio ◽  
Strong Function ◽  
Work Input ◽  
Desalination Plants ◽  
Minimum Work ◽  
Optimum Recovery

Abstract A general relation is obtained for the minimum work input requirement for desalination processes using the second-law of thermodynamics. The relation developed can be used to determine the minimum work input for any salinity of the incoming water, and the recovery ratio. It is also shown that there is a lower and an upper limit for the minimum work, corresponding to recovery ratios of 0% and 100%, respectively. The minimum work input per unit mass of fresh water produced is determined for various salinities of incoming water, and the salinities of fresh water produced, and the results are tabulated and plotted. It is shown that the minimum work is a strong function of salinity, and increases with salinity and the recovery ratio. It is also shown that the minimum work input requirement remains fairly constant for recovery ratios of up to about 80%; the minimum work increases drastically at high recovery ratios; and an optimum value of recovery ratio exists to minimize the power consumption of actual desalination plants. But the value of this optimum recovery ratio decreases with increasing salinity of the incoming saline water. The results presented in this paper can be used as a basis to evaluate the performance of actual desalination plants.

The theory of conditional invariance. I

1968 ◽  
Vol 305 (1482) ◽  
pp. 405-427 ◽  
Keyword(s):  
Bound States ◽  
General Relation ◽  
Variable Parameter ◽  
Geometric Invariance ◽  
Hermitian Conjugate ◽  
New Type ◽  
Definition Of ◽  
Conditional Invariance ◽  
Conditional Constant ◽  
The Continuum

In order to extend the use of group theoretical arguments to the problem of accidental degeneracy in quantum mechanics, a new type of constant of the motion, known as a conditional constant of the motion, is introduced. Such a quantity, instead of commuting with the Hamiltonian H for the system, satisfies the more general relation H A = A † H , where A † denotes the hermitian conjugate (adjoint) of the conditional constant of the motion A . This expression reduces, if A is hermitian, to the usual definition of a constant of the motion. Otherwise it defines a new type of invariance, and it is this which will be referred to as conditional invariance. A discussion of the difficulties arising from the lack of hermiticity of A , which is of course essential to its definition, is given. In particular it is shown, under fairly general conditions, that the process of introducing a variable parameter in the Hamiltonian enabling it to have simultaneous eigenfunctions with A , gives rise to an eigenvalue equation in this parameter with respect to which A may be chosen to be hermitian. Conditional invariance is contrasted with both dynamical and geometric invariance. It is found to be sometimes replaceable by either of the latter forms of invariance and for such, explicit conditions are given. Some applications of conditional invariance are discussed. These include a study of the crossing of potential energy curves, a new model of symmetry breaking, a possible means of calculating the exact number of bound states for certain potentials and conditions for the existence of bound states near to the continuum.

scholarly journals A networked voting rule for democratic representation

2018 ◽  
Vol 5 (3) ◽  
pp. 172265 ◽  
Author(s):  
Alexis R. Hernández ◽  
Carlos Gracia-Lázaro ◽  
Edgardo Brigatti ◽  
Yamir Moreno
Keyword(s):  
Large Scale ◽  
Selection Process ◽  
General Relation ◽  
Community Size ◽  
Rule Based ◽  
Voting Rule ◽  
Large Populations ◽  
Negative Effect ◽  
High Connectivity ◽  
Better Than

We introduce a general framework for exploring the problem of selecting a committee of representatives with the aim of studying a networked voting rule based on a decentralized large-scale platform, which can assure a strong accountability of the elected. The results of our simulations suggest that this algorithm-based approach is able to obtain a high representativeness for relatively small committees, performing even better than a classical voting rule based on a closed list of candidates. We show that a general relation between committee size and representatives exists in the form of an inverse square root law and that the normalized committee size approximately scales with the inverse of the community size, allowing the scalability to very large populations. These findings are not strongly influenced by the different networks used to describe the individuals’ interactions, except for the presence of few individuals with very high connectivity which can have a marginal negative effect in the committee selection process.

High Intensity Focused Ultrasound (HIFU) Transducer Characterization Using Acoustic Streaming

2007 ◽  
Author(s):  
Prasanna Hariharan ◽  
Ronald A. Robinson ◽  
Matthew R. Myers ◽  
Rupak K. Banerjee
Keyword(s):  
High Intensity ◽  
Focused Ultrasound ◽  
Optical Measurement ◽  
Measurement Techniques ◽  
Acoustic Streaming ◽  
Acoustic Power ◽  
High Intensity Focused Ultrasound ◽  
Medical Ultrasound ◽  
Intensity Field ◽  
Streaming Velocity

A new, non-perturbing optical measurement technique was developed to characterize medical ultrasound fields generated by High Intensity Focused Ultrasound (HIFU) transducers using a phenomenon called ‘acoustic streaming’. The acoustic streaming velocity generated by HIFU transducers was measured experimentally using Digital Particle Image Velocimetry (DPIV). The streaming velocity was then calculated numerically using the finite-element method. An optimization algorithm was developed to back-calculate acoustic power and intensity field by minimizing the difference between experimental and numerical streaming velocities. The intensity field and acoustic power calculated using this approach was validated with standard measurement techniques. Results showed that the inverse method was able to predict acoustic power and intensity fields within 10% of the actual value measured using standard techniques, at the low powers where standard methods can be safely applied. This technique is also potentially useful for evaluating medical ultrasound transducers at the higher power levels used in clinical practice.

scholarly journals Investigations of the photochemical isotope equilibrium between O<sub>2</sub>, CO<sub>2</sub> and O<sub>3</sub>

2006 ◽  
Vol 6 (4) ◽  
pp. 7869-7904
Author(s):  
R. Shaheen ◽  
C. Janssen ◽  
T. Röckmann
Keyword(s):  
Room Temperature ◽  
Strong Dependence ◽  
General Relation ◽  
Oxygen Isotopic Composition ◽  
Isotopic Compositions ◽  
Dependent Relationship ◽  
Dependent Relation ◽  
Oxygen Isotopic ◽  
Isotope Equilibrium ◽  
Mass Dependent

Abstract. Contrary to tropospheric CO2 whose oxygen isotopic composition follows a standard mass dependent relationship, i.e. δ17O~0.5 δ18O, stratospheric CO2 is preferentially enriched in 17O, leading to a strikingly different relation with δ17O~1.7δ18O. The isotope anomaly is likely inherited from O3 via photolytically produced O(1D) that undergoes isotope exchange with CO2 and the anomaly may well serve as a tracer of stratospheric chemistry if details of the exchange mechanism are understood. We have studied the photochemical isotope equilibrium in UV-irradiated O2-CO2 and O3-CO2 mixtures to quantify the transfer of the anomaly from O3 to CO2 at room temperature. By following the time evolution of the oxygen isotopic compositions of CO2 and O2 under varying initial isotopic compositions of both, O2/O3 and CO2, the isotope equilibria between the two reservoirs were determined. A very strong dependence of the isotope equilibrium on the O2/CO2-ratio was established. Equilibrium enrichments of 17O and 18O in CO2 relative to O2 diminish with increasing CO2 content, and this reduction in the equilibrium enrichments does not follow a standard mass dependent relation. When molecular oxygen exceeds the amount of CO2 by a factor of about 20, 17O and 18O in equilibrated CO2 are enriched by (142±4) and (146±4), respectively, at room temperature and at a pressure of 225 hPa, independent of the initial isotopic compositions of CO2 and O2 or O3. From these findings we derive a simple and general relation between the starting isotopic compositions and amounts of O2 and CO2 and the observed slope in a three oxygen isotope diagram. Predictions from this relation are compared with published laboratory and atmospheric data.

scholarly journals El procés contra el mulat Amador de Molina per sodomia, del 1588

2018 ◽  
Vol 12 ◽  
pp. 34
Author(s):  
Jacob Mompó Navarro
Keyword(s):  
General Relation ◽  
European History ◽  
Ecclesiastical Courts ◽  
Legal Frameworks ◽  
A Minor ◽  
The Village ◽  
Sexual Repression

Resum: La sodomia ha estat perseguida al llarg de la història europea pels tribunals civils i eclesiàstics. A més, a partir de l’any 1524 la Inquisició obtingué jurisdicció plena per jutjar la sodomia als territoris d’Aragó, Catalunya i València. Amador de Molina ja havia sigut jutjat i condemnat a Múrcia, des d’on va arribar, desterrat, a la localitat d’Ontinyent. Denunciat per l’estupre d’un menor, el Tribunal de la Inquisició de València es va mostrar implacable. Junt amb la transcripció del procés, aportem en aquest article una relació general d’alguns dels treballs més significatius en l’estudi de la Inquisició i la repressió sexual, i un esbós dels marcs doctrinals i legals del pecat-delicte de sodomia. Paraules clau: sodomia, homosexualitat, pecat nefand, crim, Inquisició, repressió sexual.Abstract: Throughout European history, sodomy has been pursued by civil and ecclesiastical courts. In addition, from 1524 on, the Inquisition obtained jurisdiction to judge sodomy in the territories of Aragon, Catalonia and Valencia. Amador de Molina had been judged and sentenced in Murcia, from where he arrived, exiled, in the village of Ontinyent. Denounced by the rape of a minor, the Court of the Inquisition of Valencia was relentless. Along with the transcription of the process, in this article we provide a general relation of some of the most significant works in the study of the Inquisition and sexual repression, and an outline of the doctrinal and legal frameworks of the sin-crime of sodomy.Keywords: sodomy, homosexuality, nefarious sin, crime, Inquisition, sexual repression.

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