Showing papers on "Crossover published in 1986"

Process synthesis concepts for supercritical gas extraction in the crossover region

Abstract: A procedure is presented for designing supercritical gas extraction processes using a pure solvent fluid to effect the separation. The necessary conditions for the procedure to be applicable are the existence of crossover behavior and separable crossover pressures in the fluid phase mixture. Data are presented to support the existence of such phenomena in ternary systems, and an actual separation process has been designed and operated based upon the data. For systems exhibiting this behavior, process synthesis principles are developed to illustrate the evolution of a process flowsheet for the separation of a mixture into its pure components.

A crossover description for the thermodynamic properties of fluids in the critical region

Abstract: We have developed a “crossover” formalism that reconciles the singular asymptotic critical behavior of the thermodynamic properties of fluids with the classical behavior of these properties well away from the critical point. The proposed formalism is based on theoretical predictions for the crossover behavior suggested by the renormalization-group theory of critical phenomena. We demonstrate the formalism for a fluid whose classical behavior away from the critical point is represented by the equation of state of van der Waals.

On crossover adjustment in satellite altimetry and its oceanographic implications

Abstract: It is argued that, to remove the satellite orbital errors, the crossover adjustment method that represents orbital errors in terms of Fourier series is preferable to the conventional bias-and-tilt crossover adjustment method. However, no matter what technique is used in the crossover adjustment, orbital errors will introduce a geographically dependent error (mostly a large-scale slope, which, in terms of spherical harmonics, is represented by the degree 1 terms) into the derived sea surface topography. This is because the responsible orbital errors have left no traces in crossover differences and therefore can never be removed. However, it is possible to reduce this fundamental uncertainty substantially if the record length is long enough; its implications on observing the basin-scale ocean circulation by satellite altimetry are discussed. New methods for observing the large-scale oceanic variability are also proposed (the conventional approach being limited to observing the mesoscale variability).

Crossover from a hexatic phase to a single first-order transition in a Laplacian-roughening model for two-dimensional melting.

Abstract: We study the defect core-energy dependence of the two-dimensional melting transition by simulation of a modified Laplacian-roughening model. We determine the dependence of the hexatic phase width on core energy and use finite-size scaling to estimate bicritical exponents characterizing the crossover to first-order behavior.

The calculation of probabilities in rejecting bioequivalence.

Abstract: Methods are given for deriving the lower and upper bounds of the probabilities for rejecting bioequivalence. Except when two formulations are nearly equal, the lower and upper bounds become very close and thus give an exact probability. The methods can be used in two- or higher-way crossover or parallel groups designs. One can also determine the sample size from the equations. The results are compared with the probabilities obtained by simulation.

Irreversible aggregation of clusters at high density

Abstract: The authors consider two-dimensional clustering for a high density of clusters. They find that three regimes can be distinguished and give the criteria for crossover between them. The numerical value of the gelation threshold strongly depends on the system size.

Crossover from dissipative to conservative behaviour in period-doubling systems

Abstract: We investigate the crossover properties, between the conservative and dissipative limit, for period-doubling bifurcations in two-dimentional iterative maps; as a generic example we use the standard form of the Henon map. The approximants to the Feigenbaum constant δ lie on a universal crossover curve, which turns out to be non-monotonic. A similar curve is found for the scaling factor α. More generally, we discuss the crossover of the trajectory scaling function 1/ σ, and its properties in the conservative limit.

Automatic initiation of target crossover recovery in a pyroelectric camera

Abstract: A system and method are disclosed for initiating target crossover recovery in a pyroelectric camera by electronically detecting crossover and automatically initiating recovery in response thereto. The video signal appearing at the output of the video amplifier during readout of the vidicon tube is coupled to a level detector to detect crossover by sensing a positive signal having an amplitude greater than any such signal producible during readout arising from an optical input to the video amplifier, with reliability of detection being enhanced by use of an automatic balancing circuit providing a stable reference. The output from the level detector, indicative of sensed crossover of an area (or all) of the target of the pyroelectric tube, is either directly used to trigger an automatic target poling circuit which returns the pyroelectric tube back to normal operation, or is coupled to a time delay for delaying repoling of the target to allow an image to continue for a period of time after an area of the target has been crossed over in order to avoid loss of information.

A Monte Carlo study of crossover behaviour and solitons in an anisotropic Heisenberg chain

Abstract: The authors have examined the spin correlations and configurations of a classical Heisenberg antiferromagnetic chain with weak easy-plane anisotropy by means of a Monte Carlo simulation. The results show the expected crossover from XY to Heisenberg behaviour as the temperature is raised. Direct examination of the spin configurations shows the presence of out-of-easy-plane solitons as predicted by Mikeska (1980). However this soliton picture appears to be viable only over a rather narrow temperature range within the crossover region. It is found that the out-of-easy-plane correlation length does not have a maximum at non-zero temperature, in disagreement with transfer-matrix analysis of similar problems.

Aggregation at a surface: crossover behaviour in a biased diffusion model

Abstract: The authors introduce a biased diffusion model of aggregation at a surface, which reduces to a ballistic model in one limit. They characterise the structure of the aggregates by a variety of properties and find that it is a strong function of the parameter governing the diffusion process. For thin films there is a crossover between a regime where there are several highly ramified pseudo-one-dimensional clusters and another regime where there is a single cluster which spans the lattice in both directions.

Mean field theory of polymer crossover behavior

Abstract: An argument is presented that the exponent previously employed to describe crossover behavior of either a linear or randomly branched polymer from the theta region to the swollen or collapsed state is inconsistent with the mean field description of the polymer free energy. In place of the conventional exponent φ(d)=[2−dνθ(d)], it is suggested that mean field theory compels use of the exponent ψ(d)=[νθ(d)d−1], where νθ(d) is the index which describes the dependence of polymer length on molecular weight in the theta region. The consequences of this different choice of crossover index are discussed for crossover behavior of the polymer length and for phase separation behavior. Comparison of the results of the different predictions with both Flory–Huggins theory and e‐expansion calculations is included. For linear chains in two dimensions striking differences are found for the predicted behavior of the phase separation curve at high monomer concentrations.

Stator of rotary electric machine

Abstract: PURPOSE:To reduce the number of crossover tracks by providing a function as a crossover track at a binding ring by connecting partial leads to the ring for supporting the tracks CONSTITUTION:The coil end 14 is supported through a spacer 18 by an annular binding ring 16 bound to cleat 17 Four crossover tracks 2-5 are disposed at axial outside from the coil end 14 Three leads 19, 20, 21 to be connected by neutral point crossover track are connected to the ring 16 The ring 16 is provided in a circumferential space B of a frame, an insulating film 24 is coated so as not to electrically contact with the end 14 of the stator coil and other stator components, and to have a function as the crossover track

Programmable logic array and circuit connecting method thereof

Abstract: PURPOSE:To form a lot of functions on a PLA in a short time by organizing air bridges having a void midway into both a crossover of an input line and a counting line and a crossover of a counting line and an output line and by insulating an upper and a lower line CONSTITUTION:Either an input line group or a counting line group is formed on a substrate 11 with a metal evaporation and a photolithography After the substrate 11 on which one line group D is formed is covered with a photoresist, it is exposed and developed in order to leave only the photoresist in the position which should be a crossover in forming of another line group D The second line group U is formed in order to meet a right angle with the line group D already formed Though the second line group U adheres to the substrate 11 except at the crossover, it adheres onto a crossover insulating photoresist film 15 at the crossover and the crossover insulating photoresist film 15 includes midway Thus, all of the second line group U insulates all of the first line group D at the crossover

Quantum crossover behaviour of the N-vector model in the large- N limit

Abstract: The quantum crossover behaviour of the N -vector model in the large- N limit is studied. Using the field-theoretic renormalization group method the crossover scaling form of the inverse correlation length is obtained. The presented approach is valid in the range of the space dimensionality 2 d ⪕3.

Compatibility of the concept of adaptation level with crossover interactions caused by distribution biases

Abstract: where Ci is the overt category rating of the presented stimulus i, Jt the judgment, a and b constants which match the endpoints of the judgment scale with those of the category scale, R1 the range value, F; the frequency value, w the weight parameter, s1, sm1. and smaz the stimulus values of the presented, lowest and highest stimuli, and r; the rank of the stimulus i within the N stimuli. One of the characteristics of the range-frequency model is that psychological impression or sensation of the given stimulus is not affected by the exposure to the immediately preceding one. On the contrary, the adaptation-level(AL) theory (Helson, 1964) assumes that responses are determined in relation to the current AL, which is the pooled effect of three classes of stimuli, focal, background (or contextual) and residual ones. That is, sensation is affected by AL. AL is not necessarily constant during experimentation. It fluctuates trial by trial, depending on the presented stimulus (self-adaptation). When we consider the effect of this self-adaptation on the next trial, we should incorporate into the model the local contextual effect of the immediately preceding trial on the present one. On the other hand, the range-frequency model neglects this local effect, because both the range value Rt and the frequency value Fi are determined based on the whole stimulus set. In criticizing AL theory, Parducci (1983) and Birnbaum (1974) contended that AL theory cannot explain the crossover interactions shown in Figs. 3 and 5 in Birnbaum (1974) (here, Figs. 1 and 2), while the range-frequency model does well. Anderson (1982) also cited Birnbaum (1974)'s crossover interaction as one of evidences that sensation to the particular stimulus is constant, although he admits the possibility of nonconstancy. In this report, the author showed that these crossover interactions can be explained by the model based on the concept of adaptation level. Birnbaum (1974) outlined the psychophysical judgment as the composition of two functions; (a) the psychophysical function,