Periodic Interferometer for Measuring Relative Phase Velocity of Sound in Fluids

1965 ◽  
Vol 37 (6) ◽  
pp. 1209-1209
Author(s):  
Donald S. Moseley
Keyword(s):  
Phase Velocity ◽  
Relative Phase ◽  
Velocity Of Sound ◽  
Relative Phase Velocity

scholarly journals A Numerical Solution for the Coexisting Field of Surface and Internal Solitary Waves

2020 ◽  
pp. 1-11
Author(s):  
Taro Kakinuma ◽  
Kei Yamashita
Keyword(s):  
Phase Velocity ◽  
Internal Waves ◽  
Wave Height ◽  
Solitary Waves ◽  
Relative Phase ◽  
Numerical Solutions ◽  
Internal Solitary Waves ◽  
Surface Mode ◽  
Internal Mode ◽  
Relative Phase Velocity

The numerical solutions for the coexisting fields of surface and internal solitary waves have been obtained, where the set of nonlinear equations based on the variational principle for steady waves are solved using the Newton- Raphson method. The relative phase velocity of surface-mode solitary waves is smaller in the coexisting fields of surface and internal solitary waves than in the cases without the coexistence of internal waves. The relative phase velocity of internal-mode solitary waves is also smaller in the coexisting fields of surface and internal solitary waves than in the cases without surface waves. The interfacial position of an internal mode internal solitary wave in a coexisting field of surface and internal waves can exceed the critical level determined in the corresponding case without a surface wave. The wave height ratio between internal-mode surface and internal solitary waves is smaller than the corresponding linear shallow water wave solution, and the difference increases, as the relative wave height of internal-mode internal solitary waves is increased.

Self-induced waves in a conduit with corrugated walls. II. Experiments with air in corrugated and finned tubes

1961 ◽  
Vol 262 (1309) ◽  
pp. 179-191 ◽  
Keyword(s):  
Wave Propagation ◽  
Phase Velocity ◽  
Cross Section ◽  
Periodic Structures ◽  
Average Frequency ◽  
Small Range ◽  
Velocity Of Sound ◽  
Finned Tubes ◽  
Metal Bellows ◽  
The Waves

Metal bellows were found to produce a pure note when air was passed through them over a small range of velocity. An axial rod, restricting the stream to a narrow annular cross-section, was usually essential for speech, and sound was produced also by a narrow stream between the bellows and an external pipe. More powerful notes were obtained when the bellows inside the pipe were replaced by helically finned tubes. The pressure distribution in this arrangement was examined. The phase velocity of the waves inside the pipe was much less than the velocity of sound, and this effect is explained by applying the theory of wave propagation in periodic structures. The ratio of the average frequency, at which an air particle passed the protuberances, to the frequency of the sound emitted was usually about 1·6.

Hold-up and flooding in a vibrating plate extractor

1983 ◽  
Vol 48 (4) ◽  
pp. 989-1000 ◽  
Author(s):  
Aleš Heyberger ◽  
Helena Sovová ◽  
Jaroslav Procházka
Keyword(s):  
Relative Phase ◽  
Linear Functions ◽  
Appreciable Effect ◽  
Characteristic Velocity ◽  
Experimental Conditions ◽  
Flow Rates ◽  
Phase Velocities ◽  
The Mean ◽  
Relative Phase Velocity ◽  
Vibrating Plate

The mean volumetric hold-up of the dispersed phase and the limiting flow rates of phases in five sizes of experimental vibrating plate extractors VPE were measured and the results compared with the relations of Richardson and Zaki, Míšek and Ishii and Zuber for the relative phase velocity. The experiments were performed with the system toluene-water, toluene dispersed. All the relations were found to describe the dependence of hold-up on flow rates very well. They also allowed a satisfactory estimation of the limiting phase velocities. Within the range of the experimental conditions the characteristic velocity as well as the limiting phase velocities could be approximated by linear functions of the frequency of vibrations. For the columns studied no influence of column size on limiting velocities was detected. The deviations of individual columns from geometrical similarity, however, brought about an appreciable effect both on the hold-up and on the flooding rates. This phenomenon has been explained in terms of longitudinal hold-up profiles, the shape of which depends on the boundary conditions in the particular column. This explanation was corroborated by case studies using a polydisperse mathematical model which show that even in the presence of hold-up profiles the effect of phase velocities on the mean hold-up can be correlated by means of the investigated relations with constant parameters and that the parameters depend on the hold-up profiles form.

Friedel'S law breakdown and interpretation of stacking fault images in tetrahedral semiconductors

1987 ◽  
Vol 45 ◽  
pp. 318-319
Author(s):  
Rob. W. Glaisher ◽  
A.E.C. Spargo
Keyword(s):  
Relative Phase ◽  
Point Group ◽  
Binary Compound ◽  
Stacking Fault ◽  
Fold Axis ◽  
Atom Pair ◽  
Tetrahedral Semiconductors ◽  
Group Symmetries ◽  
Thin Crystal ◽  
Phase Differences

Images of <11> oriented crystals with diamond structure (i.e. C,Si,Ge) are dominated by white spot contrast which, depending on thickness and defocus, can correspond to either atom-pair columns or tunnel sites. Olsen and Spence have demonstrated a method for identifying the correspondence which involves the assumed structure of a stacking fault and the preservation of point-group symmetries by correctly aligned and stigmated images. For an intrinsic stacking fault, a two-fold axis lies on a row of atoms (not tunnels) and the contrast (black/white) of the atoms is that of the {111} fringe containing the two-fold axis. The breakdown of Friedel's law renders this technique unsuitable for the related, but non-centrosymmetric binary compound sphalerite materials (e.g. GaAs, InP, CdTe). Under dynamical scattering conditions, Bijvoet related reflections (e.g. (111)/(111)) rapidly acquire relative phase differences deviating markedly from thin-crystal (kinematic) values, which alter the apparent location of the symmetry elements needed to identify the defect.

Vestibular Function and Motion Sickness Susceptibility: Videonystagmographic Evidence From Oculomotor and Caloric Tests

2020 ◽  
Vol 29 (2) ◽  
pp. 188-198
Author(s):  
Cynthia G. Fowler ◽  
Margaret Dallapiazza ◽  
Kathleen Talbot Hadsell
Keyword(s):  
Phase Velocity ◽  
Motion Sickness ◽  
Repeated Measures ◽  
Short Form ◽  
Vestibular Function ◽  
Slow Phase ◽  
Test Results ◽  
Normal Range ◽  
Slow Phase Velocity ◽  
Caloric Tests

Purpose Motion sickness (MS) is a common condition that affects millions of individuals. Although the condition is common and can be debilitating, little research has focused on the vestibular function associated with susceptibility to MS. One causal theory of MS is an asymmetry of vestibular function within or between ears. The purposes of this study, therefore, were (a) to determine if the vestibular system (oculomotor and caloric tests) in videonystagmography (VNG) is associated with susceptibility to MS and (b) to determine if these tests support the theory of an asymmetry between ears associated with MS susceptibility. Method VNG was used to measure oculomotor and caloric responses. Fifty young adults were recruited; 50 completed the oculomotor tests, and 31 completed the four caloric irrigations. MS susceptibility was evaluated with the Motion Sickness Susceptibility Questionnaire–Short Form; in this study, percent susceptibility ranged from 0% to 100% in the participants. Participants were divided into three susceptibility groups (Low, Mid, and High). Repeated-measures analyses of variance and pairwise comparisons determined significance among the groups on the VNG test results. Results Oculomotor test results revealed no significant differences among the MS susceptibility groups. Caloric stimuli elicited responses that were correlated positively with susceptibility to MS. Slow-phase velocity was slowest in the Low MS group compared to the Mid and High groups. There was no significant asymmetry between ears in any of the groups. Conclusions MS susceptibility was significantly and positively correlated with caloric slow-phase velocity. Although asymmetries between ears are purported to be associated with MS, asymmetries were not evident. Susceptibility to MS may contribute to interindividual variability of caloric responses within the normal range.

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