• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.8
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• pp.593-598
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• 2007

The present study has dealt with the measuring method of ice slurry viscosity using falling sphere viscometer. The experimental apparatus was composed by test section and high-speed video system. And the spheres used in this study were alumina and glass. The main parameters were ice packing factor (IPF) and falling velocity of sphere so the acquired results were discussed for these parameters. The viscosity of ice slurry was calculated by using measured falling velocity and moving distance at instantaneous time and the Stokes hypothesis was used for this calculation. It was clarified that possible measuring range was $IPF\;=\;0.06{\sim}0.14$ of this type of measuring device and measuring method. In addition, it was clarified that the viscosity of ice slurry increased to increase of ice packing factor (IPF) of ice slurry.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.11
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• pp.1028-1034
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• 2004

Recently, the ice storage system using ice slurry has been used increasingly since it has been introduced where the rapid cooling load change is required. Because it overcomes a decrease of the melting performance and an increase of the thermal resistance on the ice layer in static ice thermal storage system. This study is performed to understand the effects of transporting ice slurry through horizontal, vertical and inclined tubes ($30^{\circ},\;45^{\circ}$). It used propylene glycol-water solution and ice particles (diameter of about 2 mm) in this experiment. The experiments were carried out under various conditions, with concentration of water solution ranging from 0 to $20wt\%$, and velocity of water solution at the entry ranging from 1.5 to 2.5 m/s. The results were as follows: Regarding the angle of inclined tube, the highest pressure loss was measured for vertical tube and the pressure loss for $45^{\circ},\;30^{\circ}$, horizontal straight tubes were lower successively. The lowest pressure loss in these tubes was measured at velocity of $2.0{\sim}2.5m/s$ and concentration of $10wt\%$. The outlet IPF was likewise stable in these ranges.

• Bulletin of the Korean Chemical Society
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• v.34 no.2
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• pp.553-557
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• 2013

The stretching vibration of OH of ice Ih is studied by Car-Parrinello molecular dynamics in regarding the effect of mixed H/D contamination while the vibrational spectrum is considered by velocity-velocity autocorrelations of the sampled ensemble. When hydrogen atoms are immersed randomly into the deuterated ice, a typical vibrational frequency of OH stretching mode is observed to be similar to that from the pure $H_2O$ ice. When focusing on the correlation of isolated neighboring OH stretching, a narrower and blue shifted peak is observed at the high frequency range as a result of the screening from the complex many body correlations by $D_2O$ environment. It is also specifically related to the symmetric intermolecular correlations between neighboring OH stretching modes. More enhanced high frequency range can be explained by the expansion of such two body correlations to collective many body correlations among all possible OH stretching modes. This contribution becomes important when it involves in chemical interactions via excitation of such vibrational states.

• Korean Journal of Applied Biomechanics
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• v.16 no.4
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• pp.49-59
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• 2006

The purpose of this study was to investigate the relations between the segments of the body, the three dimensional anatomical angle according to sweep shot in ice hockey. The subjects of this study were five professional ice hockey players. The reflective makers were attached on anatomical boundary line of body. For the movement analysis three dimensional cinematographical method(APAS) was used and for the calculation of the kinematic variables a self developed program was used with the LabVIEW 6.1 graphical programming(Johnson, 1999) program. By using Eular's equations the three dimensional anatomical Cardan angles of the joint and ice hockey stick were defined. 1. In three dimensional linear velocity of blade the Y axis showed maximum linear velocity almost impact, the X axis(horizontal direction) and the Z axis(vertical direction) maximum linear velocity of blade did not show at impact but after impact this will resulted influence upon hitting puck. 2. The resultant linear velocity of each segment of right arm showed maximum resultant linear velocity at impact. It could be suggest that the right arm swing patterns is kind of push-like movement. therefore the upper arm is the most important role in the right arm swing. 3. The three dimensional anatomical angular displacement of trunk in flexion-extension showed flexion all around the wrist shot. The angular displacement of trunk in internal-external rotation showed internal rotation angle at the backswing top and and increased the angle after the impact. while there is no significant adduction-abduction. 4. The three dimensional anatomical angular displacement of trunk showed most important role in wrist shot. and is follwed by shoulder joints, in addition the movement of elbow/wrist joints showed least to the shot. this study result showed upperlimb of left is more important role than upperlimb of right.

• Journal of Ocean Engineering and Technology
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• v.10 no.2
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• pp.20-27
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• 1996

Ice loads can determined by many factors like ice properies and dimension, velocity and type of structures. The magnitude of ice load varies with the failure mode which can be predicted by failure maps if the aspect ratio and strain rate are known. To reduce the ice force, various types of structure have been investigated and it is now known that the identor shape plays an important role in reducing ice load on Arctic offshoe structures. The conical and wedge structures are good applied examples in the Arctic region. In this study, ice forces on single wedge indentors are investigated for crushing failure mode. The ice loads on wedged indentors are compared with those on cylindrical structures. Also the concept of "ice annual"is introduced to verify the ice loads to multi and single wedge structures.tructures.

• Journal of Advanced Marine Engineering and Technology
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• v.24 no.5
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• pp.52-57
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• 2000

Recently large capacity of electric equipment and increasing in atomic power generation are shown. One of the reason is shortage of the electric power supply for air conditioning load during summer. And every consumer is concerning about economical refrigeration and air conditioning system to decreases electric power consumption and decrease in global warming. For these necessities, ice making thermal storage system is required. Therefore, in this paper, the possibility of continuous slurry ice making using flowing organic water solution in cooled circular tube has been investigated. The experiments was carried out under some parameters of concentration and velocity of water solution, temperature of cooled tube wall, and control pressure in tube, As a result, four types of operating conditions in the pipe, that was supercooling, continuous ice making, intermittent ice making and ice blockage, were classified . And it was found that the critical condition for continuous ice making was acquired as a function of these experimental parameters.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.2
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• pp.142-149
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• 2004

Recently, the government introduced the thermal storage system for reducing the electric power load. Especially, the ice slurry type has gained lots of interest due to its good heat transfer and flowing characteristics. This study was peformed to understand the effects of transporting ice slurry through elbows of various angle. Propylene glycol water solution was used and about 2 mm ice particles were circulated. The experiments were carried out under various conditions, such as concentration and velocity of water solution ranging between 0∼20 wt％, 1.5∼2.5 m/s, respectively. And elbows with 4 different angles of 30$^{\circ}$, 45$^{\circ}$, 90$^{\circ}$, 180$^{\circ}$. The differential pressure and IPF (ice packing factor) between the pipe entry and exit were measured. The tendency of pressure loss and outlet IPF in elbow is that the pressure loss was reduced as concentration and flow velocity of water solution is increased, and low value appeared at 10 wt％ and 2.5 m/s. The variation of outlet IPF was compared with the inlet IPF in the range of $\pm$20％.

• Wind and Structures
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• v.23 no.3
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• pp.253-273
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• 2016

Ice accretions on stay cables may result in the instable vibration of galloping, which would affect the safety of cable-stayed bridges. A large number of studies have investigated the galloping vibrations of transmission lines. However, the obtained aerodynamics in transmission lines cannot be directly applied to the stay cables on cable-stayed bridges. In this study, linear and nonlinear single degree-of-freedom models were introduced to obtain the critical galloping wind velocity of iced stay cables where the aerodynamic lift and drag coefficients were identified in the wind tunnel tests. Specifically, six ice shapes were discussed using section models with geometric scale 1:1. The results presented obvious sudden decrease regions of the aerodynamic lift coefficient for all six test models. Numerical analyses of iced stay cables associated to a medium-span cable-stayed bridge were carried out to evaluate the potential galloping instability. The obtained nonlinear critical wind velocity for a 243-meter-long stay cable is much lower than the design wind velocity. The calculated linear critical wind velocity is even lower. In addition, numerical analyses demonstrated that increasing structural damping could effectively mitigate the galloping vibrations of iced stay cables.

• Journal of Advanced Marine Engineering and Technology
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• v.31 no.6
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• pp.694-698
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• 2007

This present study has dealt with the effect of surfactant on the freezing of aqueous solution Sodium chloride aqueous solution was used to measure the effect of surfactant and the main parameters of this experiment were temperature of bath, revolution of stirrer. and the radial velocity of NaCl solution. The acquired main conclusions are as follows; 1) the lower super-cooling temperature make hardly to attach the ice on beaker, 2) the size of ice become smaller to add the surfactant, 3) the ice packing factor increase with increasing of stirrer revolution.

• Journal of the Korean Geotechnical Society
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• v.34 no.11
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• pp.43-55
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• 2018

AGF (Artificial Ground Freezing) method is a temporary ground improvement method which can apply to all types of soil with the purpose of high stiffness and low hydraulic conductivity. However, the groundwater flow and the heterogeneity of the ground increase the uncertainty of the ice-column formation which hinders the reliability of this method. The effects of groundwater flow and layered heterogeneity on ice-wall integrity by AGF method were analyzed using finite element analysis program for a coupled thermo-hydro phenomena in the freezing ground. Groundwater flow changes circular ice-column into elliptical shapes and increases the time required for the formation of ice walls. The previous theoretical formula overestimated the completion time of the ice wall and the critical groundwater velocity by neglecting the thermal interaction between adjacent ice-columns. Numerical results presented the corrected formula and verified the proposed equation for the dimensionless ice-wall completion time. In the layered heterogeneous ground, the thickness of the layer with higher hydraulic conductivity and its relative magnitude were found to be important factors in the ice-wall completion time and critical velocity.