• Transactions of the KSME C: Technology and Education
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• v.2 no.2
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• pp.73-80
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• 2014

Drug delivery in human upper airway was studied by the numerical simulation of oral airflow. We created an anatomically accurate upper airway model from CT scan data by using a medical image processing software (Mimics). The upper airway was composed of oral cavity, pharynx, larynx, trachea, and second generations of branches. Thin sliced CT data and meticulous refinement of model surface under the ENT doctor's advice provided more sophisticated nasal cavity models. With this 3D upper airway models, numerical simulation was conducted by ANSYS/FLUENT. The steady inspiratory airflows in that model was solved numerically for the case of flow rate of 250 mL/s with drug-laden spray(Q= 20, 40, 60 mL/s). Optimal parameters for mechanical drug aerosol targeting of predetermined areas was to be computed, for a given representative upper airways. From numerical flow visualization results, as flow-rate of drug-laden spray increases, the drag spray residue in oral cavity was increased and the distribution of drug spray in trachea and branches became more homogeneous.

• Journal of Energy Engineering
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• v.12 no.3
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• pp.223-230
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• 2003

A study was performed to measure and analyze the gas-side fouling of heat exchanger to cool the exhaust gas from sludge incinerator at ironworks. The incinerator gas passes through inside of the vertical tubes of heat exchanger to preheat the combustion air. This kind of fouling occurs at the entrance region of the heat exchanger and thus the perforated fouling plate was designed to measure the gas-side fouling and to analyze the particulate deposit. As a result of analysis, the particulate deposition rate was influenced by temperature, particulate composition and size and also the deposition patterns were different according to the location of perforated fouling plate. The computational analysis was performed to obtain the deposition rates at the perforated fouling plate and the calculation showed that the deposition rate was varied with the hole size and particulate size. It was proved that the fouling at the entrance region of heat exchanger could be measured by the perforated fouling plate designed in this study.

• The Journal of Engineering Geology
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• v.7 no.3
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• pp.217-227
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• 1997

The purpose of this study is to analyze the correlation of soil properties in coastal soft ground. For the purpose of this study, several coastal soft ground areas were selected. Many large scale construction works are being executed and will increase continuously in these soft ground areas. So, soil property in these areas is very important. The grounds forming coastal areas are affected by seawater movement. So, most of these areas consist of alluvium stratum. Therefore, soil properties of eastern and southern coastal areas are very complex. Many laboratory tests were executed with disturbed and undisturbed soil samples. Undisturbed samples were taken by using thin walled tubes and transported into the laboratory with caution, so as not to disturb the sample. The consistent rate of fine-grained content in these areas is over 90%. Also, these areas contain higher water content and clay content. Therefore, knowing these soil properties, it is possible to safely design fabrics and constructions.

• Journal of Sensor Science and Technology
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• v.23 no.4
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• pp.245-250
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• 2014

When the charged particle travels in transparent medium with a velocity greater than that of light in the same medium, the electromagnetic field close to the particle polarizes the medium along its path, and then the electrons in the atoms follow the waveform of the pulse which is called as Cerenkov light or radiation. This type of radiation can be easily observed in a spent fuel storage pit. In optical fibers, the Cerenkov light also can be generated due to their dielectric components. Accordingly, the radiation-induced light signals can be obtained using optical fibers without any scintillating material. In this study, to measure the intensities of Cerenkov radiation induced by gamma-rays, we have fabricated the fiber-optic Cerenkov radiation sensor system using silica optical fibers, plastic optical fibers, multi-anode photomultiplier tubes, simulated spent fuel assembly and a scanning system. To characterize the Cerenkov radiation generated in optical fibers, the intensities of Cerenkov radiation generated in the silica and plastic optical fibers were measured. Also, we measured the longitudinal distribution of gamma rays emitted from the Ir-192 isotope by using the fiber-optic Cerenkov radiation sensor system and simulated spent fuel assembly.

• Textile Coloration and Finishing
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• v.28 no.4
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• pp.246-252
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• 2016

In comparison to metal alloys, braided composite features a high impact resistance and crash energy absorption potential, and also it still remained competitive stiffness and strength properties. Braiding angle is one of the most important parameters which affect the mechanical behaviors of braided composite. This paper presents transverse low velocity impact failure behavior analysis on the carbon 3D triaxial braided composite tube with the braiding angle of $20^{\circ}$, $50^{\circ}$ and $80^{\circ}$. The flexural behaviour of 3D triaxial braided composite tube under bending loads was studied by conducting quasistatic three point bending test. Also, the low velocity impact responses of the braided composite tubes were also tested to obtain load-displacement curves and energy absorption. Consequently, the increase of the braided angle, the peak load also increases owing to the bigger bending stiffness.

• Applied Chemistry for Engineering
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• v.29 no.3
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• pp.264-269
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• 2018

PSf/D2EHPA/TBP/CNTs beads were prepared by immobilizing carbon nanotubes (CNTs) and two extractants, di-(2-ethylhexyl)-phosphoric acid (D2EHPA) and tributyl phosphate (TBP) on polysulfone (PSf). The prepared PSf/D2EHPA/TBP/CNTs beads were characterized by SEM, TGA, and FTIR. The removal rate of Sr(II) by PSf/D2EHPA/TBP/CNTs beads was well described by the pseudo-second-order kinetic model. The maximum removal capacity of Sr(II) obtained from Langmuir isotherm was found to be 5.52 mg/g. The results showed that the removal efficiency of Sr(II) by PSf/D2EHPA/CNTs beads prepared in this study was significantly improved compared to that of using PSf/D2EHPA/CNTs beads without TBP.

• Transactions of the Korean Society of Mechanical Engineers
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• v.14 no.1
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• pp.251-258
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• 1990

Optimal design of heat exchanger for closed CO$_{2}$ gas turbine plant of three processes selected from the result of cycle analysis have been discussed previously paper(I) has been carried out under specified inlet and outlet conditions. Independent variables such as number of parallel connection, tube diameter, shell side and tube side pressure loss as well as dependent variables such as shell diameter, number of tubes, number of serial connections were all characterized according to the standardization or so. Search method was used to construct a computer simulation together with the calculation of heat transfer rate by logarithmic mean temperature difference method. Strength analysis of major parts was carried to examine their dimensions satisfying heat transfer and pressure loss requirements.

• Korean Journal of Clinical Laboratory Science
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• v.45 no.4
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• pp.149-153
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• 2013

Candidiasis is a fungal infection of the most common causes; generally, opportunistic infections occur often in patients with weakened immune systems. Because of high rates in fungal infection patients and increasing frequency of being isolated from clinical materials, quickly identifying of Candida albicans is critical. By identifying 404 yeast cell strains of referred samples via API 20C kits, NGL and PRO tests and Germ tube (GT) test were conducted and compared. In the 3.0 McFarland yeast cells, 0.1% ${\rho}-nitrophenyl-N-acetyl-{\beta}-D-galactosaminide$ (NGL) and 0.04% ${\small{L}}$-proline ${\beta}$-naphtylamide (PRO) were each put in test tubes and incubated at $35^{\circ}C$ for 15, 30, 60 and 90 minutes. Afterwards, 1 drop of 2% NaOH was applied, and if the color turned yellow; it was positive for NGL test. Afterwards, 1% ${\rho}$-dimethylaminocinnamaldehyde was applied, and if the upper layer turned pink or red, it was positive for PRO test. NGL and PRO tests were conducted for all C. albicans and identified accurately within 30 minutes. In NGL, PRO test, false-positive, negative were not seen, whereas, GT test showed false-positive in 1 strain and false-negative in 3 strains. Therefore, sensitivity and specificity of NGL, PRO tests were 100% and 99.5%, respectively, and positive and negative predictive rate were 99.5% and 100%, respectively. However, GT test sensitivity and specificity were 98.5% and 99.5%, respectively, and positive and negative predictive rates were 99.5% and 98.5%, respectively. In conclusion, NGL, PRO tests are better than GT tests for sensitivity and specificity, therefore, these reliable tests will be useful in clinical laboratories.

• Fire Science and Engineering
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• v.15 no.3
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• pp.7-13
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• 2001

In this paper, we had analyzed comsbustion gases according to pyrolysis $600^{\circ}c$, $800^{\circ}c$ and $1000^{\circ}c$ for polymeric material using a GASTEC colorimetric gas detector tube in order to combustion gases toxicity evaluation for flame retardant untreated ply wood, flame retardant treated ply wood, flexible polyvinyl chloride and flexible polyurethane foam of polymeric material. As a result, comsbustion gases producted from small specimens of polymeric material had reached fatal to man at a 30 minute exposure time that had possesed toxicity index. Toxicity index at pyrolysis $800^{\circ}c$ of flexible polyvinyl chloride was 31.74. Flexible polyvinyl chloride was the highest toxicity index of flame retardant untreated ply wood, flame retardant treated ply wood, flexible polyvinyl chloride and flexible polyurethane foam. The comsbustion gases producted commonly no concern with pyrolysis temperature had analyzed carbon dioxide($CO_2$) and carbon monoxide(CO). Toxicity index had investigated differently according to pyrolysis temperature even a similar materal.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.05a
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• pp.312-317
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• 2005

Fluid-elastic instability and turbulence excitation for an under developing steam generator are investigated numerically. The stability ratio and the amplitude of turbulence excitation are obtained by using the PIAT (Program for Integrity Assessment of Steam Generator Tube) code from the information on the thermal-hydraulic data of the steam generator. The aspect ratio, the ratio between the height of U-tube from the upper most tube support plate (h) and the width of two vertical portion of U-tube (w), is defined for geometric parameter study. Several aspect ratios with relocation of tube support plates are adopted to study the effects on the mode shapes and characteristics of flow-induced vibration. When the aspect ratio exceeds value of 1, most of the mode shapes at low frequency are generated at the top of U-tube. It makes very high value of the stability ratio and the amplitude of turbulent excitation as well. We can consider that the local mode shape at the upper side of U-tube will develop the wear phenomena between the tube and the anti-vibration bars such as vertical, horizontal, and diagonal strips. It turns out that the aspect ratio reveals very important parameter for the design stage of the steam generator. The appropriate value of the aspect ratio should be specified and applied.