Constant Pressure Systems for Multiple Actuators

2021 ◽  
pp. 449-455
Corpora ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. 69-90 ◽  
Author(s):  
Andrew Wilson

Contemporary depth psychology is under constant pressure to demonstrate and strengthen its evidence base. In this paper, I show how the analysis of large corpora can contribute to this goal of developing and testing depth-psychological theory. To provide a basis for evaluating statements about foot and shoe fetishism, I analyse the thirty-six most frequent three-word phrases (or trigrams) in a corpus of about 1.6 million words of amateur fetish stories written in the German language. Zipfian methods from quantitative linguistics are used to specify the number of phrases for analysis and I argue that these reflect the core themes of the corpus. The analysis reveals three main dimensions. First, it corroborates the observations of the early sexologists that foot and shoe fetishism is very closely intertwined with sadomasochism. Secondly, it shows that genitalia-related phrases are also common, but an examination of their contexts questions Freud's theory that fetishism results from an assumption of female castration. Thirdly, it reveals that the mouth also plays a key role; however, the frequent co-presence of genitalia references in the same texts does not seem to support straightforwardly the most common alternative theory of fetishism based on object relations. Future research could valuably extend this approach to other fetishes and, in due course, to other depth-psychological constructs.


Author(s):  
V. S. IVANOV ◽  
◽  
V. S. AKSENOV ◽  
S. M. FROLOV ◽  
P. A. GUSEV ◽  
...  

Modern high-speed unmanned aerial vehicles are powered with small-size turbojets or ramjets. Existing ramjets operating on the thermodynamic cycle with de§agrative combustion of fuel at constant pressure are efficient at flight Mach numbers M ranging from about 2 to 6.


1985 ◽  
Vol 40 (10) ◽  
pp. 959-967
Author(s):  
A. Salat

The equivalence of magnetic field line equations to a one-dimensional time-dependent Hamiltonian system is used to construct magnetic fields with arbitrary toroidal magnetic surfaces I = const. For this purpose Hamiltonians H which together with their invariants satisfy periodicity constraints have to be known. The choice of H fixes the rotational transform η(I). Arbitrary axisymmetric fields, and nonaxisymmetric fields with constant η(I) are considered in detail.Configurations with coinciding magnetic and current density surfaces are obtained. The approach used is not well suited, however, to satisfying the additional MHD equilibrium condition of constant pressure on magnetic surfaces.


1964 ◽  
Vol 86 (3) ◽  
pp. 320-326 ◽  
Author(s):  
E. S. Nowak

A parametric equation of state was derived for water and water vapor in the critical region from experimental P-V-T data. It is valid in that part of the critical region encompassed by pressures from 3000 to 4000 psia, specific volumes from 0.0400 to 0.1100 ft3/lb, and temperatures from 698 to 752 deg F. The equation of state satisfies all of the known conditions at the critical point. It also satisfies the conditions along certain of the boundaries which probably separate “supercritical liquid” from “supercritical vapor.” The equation of state, though quite simple in form, is probably superior to any equation heretofore derived for water and water vapor in the critical region. Specifically, the deviations between the measured and computed values of pressure in the large majority of the cases were within three parts in one thousand. This coincides approximately with the overall uncertainty in P-V-T measurements. In view of these factors, the author recommends that the equation be used to derive values for such thermodynamic properties as specific heat at constant pressure, enthalpy, and entropy in the critical region.


Author(s):  
Amarjot Singh Bhullar ◽  
Gospel Ezekiel Stewart ◽  
Robert W. Zimmerman

Abstract Most analyses of fluid flow in porous media are conducted under the assumption that the permeability is constant. In some “stress-sensitive” rock formations, however, the variation of permeability with pore fluid pressure is sufficiently large that it needs to be accounted for in the analysis. Accounting for the variation of permeability with pore pressure renders the pressure diffusion equation nonlinear and not amenable to exact analytical solutions. In this paper, the regular perturbation approach is used to develop an approximate solution to the problem of flow to a linear constant-pressure boundary, in a formation whose permeability varies exponentially with pore pressure. The perturbation parameter αD is defined to be the natural logarithm of the ratio of the initial permeability to the permeability at the outflow boundary. The zeroth-order and first-order perturbation solutions are computed, from which the flux at the outflow boundary is found. An effective permeability is then determined such that, when inserted into the analytical solution for the mathematically linear problem, it yields a flux that is exact to at least first order in αD. When compared to numerical solutions of the problem, the result has 5% accuracy out to values of αD of about 2—a much larger range of accuracy than is usually achieved in similar problems. Finally, an explanation is given of why the change of variables proposed by Kikani and Pedrosa, which leads to highly accurate zeroth-order perturbation solutions in radial flow problems, does not yield an accurate result for one-dimensional flow. Article Highlights Approximate solution for flow to a constant-pressure boundary in a porous medium whose permeability varies exponentially with pressure. The predicted flowrate is accurate to within 5% for a wide range of permeability variations. If permeability at boundary is 30% less than initial permeability, flowrate will be 10% less than predicted by constant-permeability model.


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