Determination of modes in the ice-water bi-layer waveguide

OBJECTIVE: Evaluation of head-position dependency during the ice-water test is essential when the test is indicated. Because ice-water irrigation (IWI) in the prone position is frequently skipped in many laboratories, we investigated the importance of evaluating position dependency in an ice-water test. DESIGN AND SETTING: Twenty-five unilateral peripheral vestibulopathy patients showing no nystagmus during warm irrigation were included. IWI was performed in supine and prone positions, and maximum slow-phase velocity and direction of nystagmus were assessed by using video nystagmography. RESULTS: Eleven cases showed head-position dependency and were interpreted as hypofunctional. Fourteen cases showed no dependency, suggesting the absence of end organ function. In the latter group, 6 patients showing definite nystagmus in supine position could have been misinterpreted as hypofunctional, had it not been for prone-position results. CONCLUSIONS: Evaluation of head position dependency by using IWI is important in the determination of lateral semicircular canal function.

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Experimental Determination of Temperature-Dependent Thermal Conductivity of Solid Eicosane-Based Nanostructure-Enhanced Phase Change Materials

Volume 2: Heat Transfer Enhancement for Practical Applications; Fire and Combustion; Multi-Phase Systems; Heat Transfer in Electronic Equipment; Low Temperature Heat Transfer; Computational Heat Transfer ◽

10.1115/ht2012-58504 ◽

2012 ◽

Author(s):

Mahdi Nabil ◽

J. M. Khodadadi

Keyword(s):

Thermal Conductivity ◽

Phase Change Materials ◽

Small Diameter ◽

Copper Oxide Nanoparticles ◽

Water Bath ◽

Conductivity Data ◽

Vacuum Oven ◽

Thermal Conductivity Data ◽

Ice Water

The effective thermal conductivity of composites of eicosane and copper oxide nanoparticles in the solid state was measured experimentally by using the transient plane source technique. Utilizing a controllable temperature bath, measurements were conducted at various temperatures between 10 and 35°C for the solid samples. In the course of preparation of the solid specimen, liquid samples (0, 1, 2, 5 and 10 wt%) were poured into small diameter molds and were degased within a vacuum oven. The molds were then subjected to either ambient solidification or ice-water bath freezing method. Measured thermal conductivity data of the composites were found to be nearly independent of the measurement temperature for a given loading of CuO nanoparticles regardless of the solidification procedure. Irrespective of the solidification method, as the melting temperature was approached, thermal conductivity data of the solid disks rose sharply for both sets of experiments. The composites prepared using the ice-water bath solidification scheme consistently exhibited lower values of thermal conductivity when compared to the samples which prepared under ambient solidification method. This behavior might be due to the greater void percentage of ice-water bath samples and/or crystal structure deviations due to phase transition method.

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Improvement in Determination of Ice Water Content from Two-Dimensional Particle Imagery. Part II: Applications to Collected Data

Journal of Applied Meteorology and Climatology ◽

10.1175/jam2399.1 ◽

2006 ◽

Vol 45 (9) ◽

pp. 1291-1303 ◽

Cited By ~ 23

Author(s):

R. Paul Lawson ◽

Brad A. Baker

Keyword(s):

Particle Size ◽

Water Content ◽

Particle Mass ◽

Two Dimensional ◽

Projected Area ◽

Ice Water Content ◽

Rms Error ◽

Particle Size And Shape ◽

Ice Water

Abstract In Part I of this two-part series, a new relationship for ice particle mass M was derived based on an expanded dataset of photographed ice particles and melted drops. The new relationship resulted in a reduction of nearly 50% in the rms error in M. In this paper, new relationships for computing particle mass and ice water content from 2D particle imagery are compared with other relationships previously used in the literature. Comparison of the old and new relationships, when applied to data collected in natural clouds, shows that results using the old relationships differ from the new relationships by up to a factor of 3, depending on particle size and shape. One of the new relationships can be applied to existing (archived) datasets of two-dimensional images, provided that the number of occulted pixels in each image (i.e., projected area) is available.

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Determination of Cloud Ice Water Content and Geometrical Thickness Using Microwave and Infrared Radiometric Measurements

Journal of Climate and Applied Meteorology ◽

10.1175/1520-0450(1987)026<0878:dociwc>2.0.co;2 ◽

1987 ◽

Vol 26 (8) ◽

pp. 878-884 ◽

Cited By ~ 5

Author(s):

Man-Li C. Wu

Keyword(s):

Water Content ◽

Radiometric Measurements ◽

Ice Water Content ◽

Cloud Ice ◽

Ice Water

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Improvement in Determination of Ice Water Content from Two-Dimensional Particle Imagery. Part I: Image-to-Mass Relationships

Journal of Applied Meteorology and Climatology ◽

10.1175/jam2398.1 ◽

2006 ◽

Vol 45 (9) ◽

pp. 1282-1290 ◽

Cited By ~ 82

Author(s):

Brad Baker ◽

R. Paul Lawson

Keyword(s):

Water Content ◽

Linear Regression Analysis ◽

Crystal Habit ◽

Two Dimensional ◽

Average Mass ◽

Length Relationship ◽

Ice Water Content ◽

Rms Error ◽

Ice Water

Abstract Ice water content in natural clouds is an important but difficult quantity to measure. The goal of a number of past studies was to find average relationships between the masses and lengths of ice particles to determine ice water content from in situ data, such as those routinely recorded with two-dimensional imaging probes. The general approach in these past studies was to measure maximum length L and mass M of a dataset of ice crystals collected at a ground site. Linear regression analysis was performed on the logarithms of the data to estimate an average mass-to-length relationship of the form M = αLβ. Relationships were determined for subsets of the dataset based on crystal habit (shape) as well as for the full dataset. In this study, alternative relationships for determining mass using the additional parameters of width W, area A, and perimeter P are explored. A 50% reduction in rms error in the determination of mass relative to using L alone is achieved using a single parameter that is a combination of L, W, A, and P. The new parameter is designed to take into account the shape of the ice particle without the need to classify the crystals first. An interesting result is that, when applied to the test dataset, the same reduction in rms error is also shown to be achievable using A alone. Using A alone facilitates the reanalysis and improvement of the determination of ice water content from large existing datasets of two-dimensional images, because A is simply the number of occulted pixels in the digital images. Possible sources of error in this study are investigated, as is the usefulness of first segregating the particles into crystal habits.

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A Frost Tube for the Determination of Freezing in the Active Layer above Permafrost

Canadian Geotechnical Journal ◽

10.1139/t73-033 ◽

1973 ◽

Vol 10 (3) ◽

pp. 392-396 ◽

Cited By ~ 21

Author(s):

J. Ross Mackay

Keyword(s):

Active Layer ◽

Vertical Migration ◽

Water Interface ◽

Coarse Particles ◽

Upward Moving ◽

Ice Water

A frost tube which can be used in permafrost areas to determine both the downward and upward movements of the two freezing fronts in the active layer, during the fall freeze-back period, is described. The principle, which is based upon the differential vertical migration of fine and coarse particles resting upon an upward moving horizontal ice–water interface, is discussed. Attention is drawn to some of the ice characteristics of the active layer and top of the permafrost which result from upward freezing at the bottom of the active layer.

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A Methodology for the Determination of Drag Coefficients for Ice Floes

Journal of Offshore Mechanics and Arctic Engineering ◽

10.1115/1.3257035 ◽

1987 ◽

Vol 109 (4) ◽

pp. 381-387 ◽

Cited By ~ 4

Author(s):

O. S. Madsen ◽

M. S. Bruno

Keyword(s):

Continental Shelf ◽

Governing Equations ◽

Physical Processes ◽

Drag Coefficients ◽

Simplifying Assumptions ◽

Ice Velocity ◽

Ice Floes ◽

Ice Water ◽

Coupled Equation

Governing equations are derived for the response of partially ice-covered continental shelf waters to atmospheric and tidal forcing. The assumptions underlying these equations are discussed, with emphasis on the physical processes represented by the air-ice and ice-water drag coefficients. Combining the equations that separately govern the water and ice floe motions, a coupled ice-water equation is obtained. The coupled equation reduces, under certain simplifying assumptions, to an equation involving only the air and water velocities relative to the ice velocity. This suggests an approximate but extremely simple methodology for the determination of drag coefficients for ice floes. The methodology is applied to data obtained during BASICS and MIZEX, and shown, in the former application, to yield drag coefficients comparable to those obtained from considerably more laborious methods.

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Measurements and Analyses of Velocity Profiles and Frazil Ice-Crystal Rise Velocities During Periods of Frazil-Ice Formation in Rivers

Annals of Glaciology ◽

10.3189/s0260305500005279 ◽

1983 ◽

Vol 4 ◽

pp. 79-84 ◽

Cited By ~ 11

Author(s):

J. P. Gosink ◽

T. E. Osterkamp

Keyword(s):

Time Scale ◽

Velocity Profiles ◽

Ice Crystals ◽

Ice Formation ◽

Rise Velocity ◽

Mixed Flow ◽

Frazil Ice ◽

Time Required ◽

Ice Water

The vertical concentration distribution of frazil-ice crystals in a stream during the formation and growth of frazil ice was discussed in a preliminary way by Gosink and Osterkamp (1981). This paper extends and completes the analysis of buoyant rise velocities of frazil-ice crystals and applies the results to an interpretation of measured velocity profiles in rivers during frazil-ice events. Additional experimental data are also presented. Two time scales are defined: the buoyant time scale TB, which represents the time required for a frazil crystal to rise, buoyantly, from the river bottom to the water surface, and the diffusive tine scale TD, which represents the time required for a frazil crystal to he transported by turbulence through the depth. It is shown that the ratio of the time scales TB/TD defines the nature of the layering processes; in particular, if TB/TD<1, then buoyant forces Till lift a frazil crystal faster than turbulent diffusion can redistribute it and the flow will be layered. Conversely, if TB./TD>1, turbulent mixing will proceed faster than buoyant lifting and the flow will be well-mixed. This ratio, for frazil particles of diameter 2 mm or more, corresponds to rule-of-thumb velocity criteria developed in Norway and Canada to distinguish layered frazil-ice/water flow from well-mixed flow.The development of this theory depends in large part upon the determination of TB, which depends upon the rise velocity of frazil-ice crystals. A force balance .nodel was developed for the rise velocity of a frazil crystal. Field observations during frazil -ice formation in Goldstream Creek and in the Chatanika River north of Fairbanks are reported, including a series of measurements of the rise velocities of frazil-ice crystals. Typical particle size of frazil ice was about 2 mm with a rise velocity of about 10.0 mm s -1. The agreement of measured rise velocities with the theoretical model is good considering uncertainties in the drag coefficient and in the determination of frazil crystal sizes under field conditions.Velocity profiles in the Chatanika River and in Goldstream Creek during frazil formation suggest that the time-scale ratio may serve as a transition criterion between layered frazil-ice/water flow and well-mixed flow. This ratio was calculated with the rise velocity of frazil-ice crystals arbitrarily chosen to be 0.01 m s−1.

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Activation Distance Determination of Rate Controlling Obstacles in the Age Hardening of a Quasi-Binary Al-Mg2Si Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.794-796.455 ◽

2014 ◽

Vol 794-796 ◽

pp. 455-460

Author(s):

Bradley Diak ◽

Rathna Lanerolle

Keyword(s):

Three Dimensional ◽

Natural Aging ◽

Rate Sensitivity ◽

Atom Probe ◽

Single Step ◽

Age Hardening ◽

Distance Analysis ◽

Acta Mater ◽

Ice Water

The age hardening response of a quasi-binary Al-Mg2Si alloy was studied using activation distance analysis of precise strain rate sensitivity experiments at 78 and 300K. The alloy of Al-0.7Mg-0.33Si-0.024Fe-0.006Ti(at.%) has a stochiometrically balanced composition of Mg2Si. The alloy was solutionized at 550°C and ice water quenched before ageing in one of two ways: single-step or multi-step ageing. For single-step ageing: specimens were naturally aged for 70 days at room temperature (RT); pre-aged for 16 hours at 70°C; or artificially aged for 30 min or 10 hours at 175°C. For multi-step ageing: specimens were pre-aged at 70°C for 16 hours after natural ageing for 70 days at RT; artificially aged for 30 min or 10 hours at 175°C after pre-aging at 70°C for 16 hours; or artificially aged for 10 hours at 175°C after natural aging for 70 days at RT. The activation analysis reveals rate controlling obstacle dimensions ranging from 0.3 to 10 nm depending upon the ageing condition. A comparison is made to a prior three dimensional atom probe ageing study of the same alloy [Murayama and Hono, Acta Mater., 47 (1999) 1537-1578.].

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