• Tunnel and Underground Space
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• v.15 no.3 s.56
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• pp.223-227
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• 2005

The physical and mechanical properties of volcanic glass, which is distributed in the Samho area, South Korea were studied. Laboratory rock tests were carried out in order to obtain the various properties of rocks. Specific gravity, water content, absorption, porosity and wave velocity were measured for the physical properties. Uniaxial and triaxial compressive tests, Brazilian test and point load test were also performed for the mechanical properties. The tests of volcanic glass revealed that the apparent specific gravity, water content and absorption were 2.28, $1.67\%$ and $1.72\%$, respectively. Porosity $(3.87\%)$ was lower, whereas P-wave velocity (5330m/s) and S-wave velocity (2980 m/s) were relatively higher. Brazilian tensile strength ot 7.2MPa, and point load strength of 2.6MPa were among the mechanical properties of the rock. Uniaxial compressive strength (62.4MPa) estimated ken point load strength was very closed to the value (66.0MPa) from the uniaxial compressive test. Young's modulus and Poisson's ratio were E=43.2 GPa and v=0.28, respectively. Drawing the tangent line to Mohr-Coulomb failure criterion showed the cohesion of 20.1MPa and internal fraction angle of $28.6^{\circ}$.

• Journal of Veterinary Clinics
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• v.38 no.3
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• pp.163-168
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• 2021

A 6-year-old, spayed female, Maltese dog with tachypnea and dry cough was presented to Gyeongsang National University Veterinary Medical Teaching hospital. On physical examination, its respiration rate was 132 per minute. Decreased partial pressure of oxygen, partial pressure of carbon dioxide, and hyperlactatemia were found on arterial blood gas analysis. Its diastolic blood pressure was 80 mmHg. Auscultation revealed arrhythmia. Electrocardiogram revealed P pulmonale, P mitrale, and ventricular premature complexes. Thoracic radiographs revealed mild enlargement of both atrium and moderate enlargement of the left ventricular. There was also a moderate alveolar pattern in the right and caudal part of the left cranial lung lobe. Two-dimensional echocardiography showed enlargement of generalized four chambers without remarkable findings of valvular degeneration. M-mode echocardiography showed decreased left ventricular fractional shortening and enlarged left ventricular internal diameter at both end-systolic and end-diastolic. Color-flow Doppler imaging revealed eccentric turbulent flow starting below the left ventricular outflow tract and extending into the left atrium during systole. Spectral Doppler recordings revealed a high velocity flow through the mitral, tricuspid, aorta, and pulmonic regurgitation. Restrictive transmitral flow revealed high E-wave velocity, short E-wave deceleration time, and reduced A-wave velocity. There was also low ejection velocity thorough left ventricular out tract flow. Based on echocardiographic examination, dilated cardiomyopathy was the tentative diagnosis. The dog was medicated with inotropes, angiotensin converting enzyme inhibitor, and diuretics. At the 10-day following-up, the dog died suddenly. This report describes echocardiographic diagnosis and prognosis of dilated cardiomyopathy rarely reported in small breed dogs.

• Journal of Ocean Engineering and Technology
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• v.28 no.5
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• pp.429-439
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• 2014

The target echoes contain information on the target such as the orientation, kinematics, and internal structure, as well as the external geometrical shape of the target. In addition, the pattern of the target echoes depends on the arrangement of the transmitters and receivers in space. Therefore, the study of the target echoes in a multi-static SONAR system can be useful for detecting and tracking submerged objects using an underwater surveillance system. For this purpose, an acoustic measuring system for multi-static target echoes was designed and tested in an acoustic water tank. Some preliminary data are presented and discussed.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.6
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• pp.1510-1517
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• 1995

A theoretical method is described to simulate the propagation of turbulent premixed flames in a closed vessel. The objective is to develop and test an efficient technique to predict the propagation speed of flame as well as the geometric structure of the flame surfaces. Flame is advected by the statistically generated turbulent flow field and propagates as a wave by solving twodimensional Hamilton-Jacobi equation. In the simulation of the unburned gas flow field, following turbulence properties were satisfied: mean velocity field, turbulence intensities, spatial and temporal correlations of velocity fluctuations. It is assumed that these properties are not affected by the expansion of the burned gas region. Predictions were compared with existing experimental data for flames propagating in a closed vessel charged with hydrogen/air mixture with various turbulence intensities and Reynolds numbers. Comparisons were made in flame radius growth rate, rms flame radius fluctuations, and average perimeter and fractal dimensions of the flame boundaries. Two dimensional time dependent simulation resulted in correct trends of the measured flame data. The reasonable behavior and high efficiency proves the usefulness of this method in difficult problems of flame propagation such as in internal combustion engines.

• Journal of the Society of Naval Architects of Korea
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• v.42 no.4 s.142
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• pp.330-340
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• 2005

Compressible two-phase flow is analyzed based on the arbitrary Lagrangian-Eulerian (ALE) formulation. For water, Tamman type stiffened equation of state is used. Numerical fluxes are calculated using the ALE two-phase Godunov scheme which assumes only that the speed of sound and pressure can be provided whenever density and internal energy are given. Effects of the approximations of a material interface speed are Investigated h method Is suggested to assign a rigid body boundary condition effectively To validate the developed code, several well-known problems are calculated and the results are compared with analytic or other numerical solutions including a single material Sod shock tube problem and a gas/water shock tube problem The code is applied to analyze the refraction and transmission of shock waves which are impacting on a water-gas interface from gas or water medium.

• Proceedings of the Korea Committee for Ocean Resources and Engineering Conference
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• 2003.10a
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• pp.127-132
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• 2003

In a today industry, the welding is doing a many portion in structure manufacture. This study is simulated heat of heat-effected zone and researched a mechanical properties and ultrasonic characteristic in used the SS400 and the STS304. As the result mechanical properties of steel that become drawing decreased because of remaining stress by strain gardening according as simulated heat temperature rises, but according as temperature rises in material that do simulated heat after have done annealing, mechanical propensity was improved. The velocity and attenuation become different by effect of remaining stress than effect of material internal microstructure in ultrasonic wave test. In the case of STS304, there was change in mechanical properties by effect that is by strain hardening, but there was no change in material that simulated heat after annealing. When become drawing in ultrasonic waves test, according as simulated heat temperatures rise, change of attenuation coefficient is looked, but material that simulated heat after annealing was no change almost both the volocity and attenuation.

• Journal of Advanced Research in Ocean Engineering
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• v.3 no.1
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• pp.1-14
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• 2017

The safety analysis of an earthquake is carried out during the operation of a subsea pipeline and an onshore pipeline. Several cases are proposed for consideration. In the case of a buried pipeline, permanent ground deformation by the earthquake and an increase of internal pressure by the acceleration of the earthquake should be considered. In the case of a subsea pipeline, a bending moment is caused by liquefaction of the backfill material on a trenched seabed, etc., which results in a high bending moment of the buried pipeline. The bending moment causes the collapse of the subsea pipeline or a leak of crude oil or gas, which results in economic loss due to enormous environmental contamination and social economic loss owing to operation functional failure. Thus, in order to prevent economic loss and operation loss, structurally sensitive design with regard to seismic characteristics must be performed in the buried pipeline in advance, and the negative impact on the buried pipeline must be minimized by conducting a thorough analysis on the seabed and backfilling material selection. Moreover, it is proposed to consider the selection of material properties for the buried pipeline. A more economical review is also required for detailed study.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.1
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• pp.54-60
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• 2003

Compound choking frequently occurs at a minimum area of the flow passage, where two or more streams which have different stagnation properties are merged. This phenomenon is especially important in that the flow choking may not be given by Mach number, M=1 at the nozzle throat. In order to obtain a detailed understanding of the flow characteristics involved in the compound flow choking, the two-dimensional, compressible, Wavier-Stokes equations are solved using a fully implicit finite volume method and the predicted solutions are compared with the results of the one-dimensional theoretical analysis. Stagnation pressure and temperature of each stream are changed to investigate the effects on the compound choking. The results show that stagnation pressures of each stream affect Mach number and static pressure distributions downstream of the exit of the convergent nozzle. However, the flow characteristics of the compound choking are not significantly dependent on the total temperature ratio.

• International Journal of Aeronautical and Space Sciences
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• v.10 no.1
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• pp.91-97
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• 2009

It is undertaken systematization of results of satellite and ground observation parameters characterizing a current condition and climatic variability of two selected geographical areas. One of them covers territory of Azerbaijan and another covers a wide area of Caspian See region. Average values and mean square deviations of following values are investigated: outgoing long wave radiation during a day and night (in nebulosity and cloudless). absorbed within a day of the stream of a sunlight of the system in "a terrestrial surface-atmosphere". degree of a covering by clouds of the selected areas during a day and at night, ground temperature values of air. pressure and speed of a wind. Monthly average values of corresponding parameters create a basis of suggested investigations. It has been presented features of a time course of investigated parameters for each month and year in the whole due to the continuously observations since 1982-2000. The scientific problem consists that there are no existed models which authentically would be cover the main aspects of a realities specified changes: they are identified by economic activities. growth of the population and other features of development of a human society or internal fluctuations of biogeophysical/climatic system. Possibilities of predictability of biosphere and climate changes depend on available timely supervision. adequacy of construction of appropriate models. understanding of mechanisms of direct and feedback influences in such complicated systems.

• Journal of Information Display
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• v.12 no.3
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• pp.115-119
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• 2011

Optically isotropic liquid crystal (LC) mixture such as blue-phase LC and nanostructured LC composites exhibit the advantages of fast response time, high contrast ratio and wide-viewing angle due to the induced birefringence along the horizontal electric field. Utilizing this mixture, a novel single cell gap in-plane switching-type polymer-stabilized blue-phase transflective liquid crystal display by embedding the nanowire grid polarizer as a polarization-dependent reflective polarizer in the R region is proposed. This device can be used as a normal black mode without any quarter-wave plate or patterned in-cell phase retarder. Moreover, the transmittance is identical to the reflectance so that it will be suitable for single gamma driving. Detailed electro-optic performances, such as voltage-dependent light efficiency and viewing angle of the proposed device configuration, are investigated.