• Journal of the Korean Electrochemical Society
• /
• v.6 no.4
• /
• pp.250-254
• /
• 2003

In this study, the IR drop theory was adopted to explain the initiation of crevice corrosion in the framework of IR drop in crevice electrolyte. Furthermore, the electrochemical polarization was measured to study the mechanism of crevice corrosion for type STS430 stainless steel. lest method adopts under condition that the size of specimen is $10\times20\times5mm,\;in\;1N\;H_2SO_4+0.1N\;NaCl$ solution, and the artificial crevice gap sizes are three kinds, the Micro capillary tube size is inner diameter 0.04 mm, outer diameter 0.08 mm. Crevice corrosion is measured under the applied voltage of passivation potential -200mV/SCE, resulted from anodic potentio-dynamic polarization to the external surface along the crevice. The potential difference was measured by depth profile by Micro capillary tube which inserted in the crevice. The obtained results of this study showed that 1) As artificial crevice gap size became narrow, the current density was increased, whereas no crevice corrosion was found in the crevice gap size $3\times0.5\times16mm\;in\;1N\;H_2SO_4+0.1N\;NaCl\;solution\;at\;20^{\circ}C$ 2) potential of the crevice was about from -220 to -358mV which is lower than that of external surface potential of -200mV The results so far confirmes that the potential drop(so-called IR drop) in the crevice is one of the major mechanisms the process of crevice corrosion for 430 stainless steel.

• Journal of Mechanical Science and Technology
• /
• v.17 no.10
• /
• pp.1507-1519
• /
• 2003

The two-phase flow patterns for both non-loop and loop type oscillating capillary tube heat pipes (OCHPs) were presented in this study. The detailed flow patterns were recorded by a high-speed digital camera for each experimental condition to understand exactly the operation mechanism of the OCHP. The design and operation conditions of the OCHP such as turn number, working fluid, and heat flux were varied. The experimental results showed that the representative flow pattern in the evaporating section of the OCHP was the oscillation of liquid slugs and vapor plugs based on the generation and growth of bubbles by nucleate boiling. As the oscillation of liquid slugs and vapor plugs was very speedy, the flow pattern changed from the capillary slug flow to a pseudo slug flow near the annular flow. The flow of short vapor-liquid slug-train units was the flow pattern in the adiabatic section. In the condensing section, it was the oscillation of liquid slugs and vapor plugs and the circulation of working fluid. The oscillation flow in the loop type OCHP was more active than that in the non-loop type OCHP due to the circulation of working fluid in the OCHP. When the turn number of the OCHP was increased, the oscillation and circulation of working fluid was more active as well as forming the oscillation wave of long liquid slugs and vapor plugs in the OCHP. The oscillation flow of R-142b as the working fluid was more active than that of ethanol and the high efficiency of the heat transfer performance of R -142b was achieved.

• Korean Journal of Veterinary Research
• /
• v.26 no.1
• /
• pp.175-185
• /
• 1986

The measurement of angled erythrocyte sedimentation rate (ESR), as a replacement for perpendicular ESR, for cattle blood was scrutinized since it has been well known that perpendicular ESR in cattle is too slow to be adopted as an effective clinical test. Samples of blood were taken from 186 Korean native cattle over 2 years old. The results obtained in the experiment were summarized as follows. 1. Average values of perpendicular ESR/24hrs in 15 apparently healthy cattle, as measured by Wintrobe, Westergren and capillary tubes, were $5.8{\pm}2.2$, $11.1{\pm}3.7$ and $10.4{\pm}4.5%$ respectively, which were found to be similar to the values of perpendicular ESR/hr of normal blood of human. 2. The ESR was determined in the tubes held at 90, 75, 60, 45, 30 and 15-degree angles, using 3 types of tubes. For the diagnostic purposes, the best results were obtained from the tubes held at 45-degree angle. 3. The angled ESR values increased as the diameters of the tube-bores decreased. 4. The tube length did not affect the angled ESR(%). 5. The angled ESR values increased with the increased environmental temperature during the ESR measurement. 6. The storage temperature at $5^{\circ}C$, $20^{\circ}C$ and $35^{\circ}C$, of the blood for 24 hours did not affect the angled ESR. 7. Samples of blood were treated with 4 kinds of anticoagulants (heparin, $K_2$-EDTA, double oxalate and sodium citrate) and the ESR was determined at 45-degree angle, using capillary hematocrit tubes. The ESR values were higher in the blood samples treated with sodium citrate than in those treated with other anticoagulants. 8. By using the autologous plasma, the PCV was adjusted to be 5, 10, 20, 30, 40 and 50ml/100ml and the ESR was determined in the capillary hematocrit and Wintrobe tubes held at 45 degrees. In both of the methods the ESRs increased as the values of PCV decreased. The regressions of ESR to PCV in both 45-degree-angled capillary and Wintrobe tubes were curvilinear. For the capillary hematocrit tubes the second degree polynomial $Y=61.9779-2.3533x+0.0228x^2$ (r=0.9999) fits the data. And in the case of Wintrobe tubes the second degree polynomial $Y=27.9767-1.1314x-0.0117x^2$ (r=0.9998) fits the data. 9. The 45-degree angled ESR was determined in the blood of 71 healthy Korean native cows using capillary hematocrit tubes. The average PCV was $35.4{\pm}3.6ml/100ml$. The observed ESR/hr averaged $7.2{\pm}2.7%$, while the corrected ESR/hr to a PCV of 36ml/100ml averaged $6.6{\pm}1.3%$. From these results it was concluded that to obtain the best results the ESR/hr of Korean native cattle should be determined at 45-degree angle at room temperature($20^{\circ}C$) using capillary hematocrit tubes.

• Korean Journal of Veterinary Research
• /
• v.26 no.1
• /
• pp.187-194
• /
• 1986

The purpose of this study is to develop a new method which enables the goat ESR to be used as an effective clinical test. Blood samples were taken from 61 Korean native goats aged above one year old and the effect of tube inclinations, tube bores, tube lengths, environmental temperatures during tests and packed erythrocyte volumes (PCV) on the ESR were observed. The results were summarized as follows. 1. The ESR/hr using capillary hematocrit tube (Micro-Ht-tube) was gradually increased as the tube angle inclined from 90 (vertical) to 15 degrees and the best angle in view of both security and fast sedimentation rate was found to be an angle of 45 degrees. 2. The 45-degree angled ESR ($45^{\circ}$-ESR) increased as the diameter of tube bore decreased. 3. The tube length did not affect the $45^{\circ}$-ESR in percent. 4. The $45^{\circ}$-ESR increased with the increased environmental temperature during the ESR test. 5. The heparinized Micro-Ht tubes did not affect the $45^{\circ}$-ESR of EDTA-blood in healthy group but in anemic group. In the anemic group, the ESRs by the heparinized Micro-Ht-tubes were slightly higher than those by non-heparinized Micro-Ht-tubes. 6. By using the autologous plasma, PCV of the blood was adjusted to be 10, 20, 30, 40 and 50ml/100ml and $45^{\circ}$-ESRs were determined in the Micro-Ht-tubes. The $45^{\circ}$-ESRs increased as the values of PCV decreased. The regression of the $45^{\circ}ESR$ to PCV was curvilinear with the second degree polynomial, $Y=42.1838-1.7355X+0.0180X^2$(r=0.9997). 7. The $45^{\circ}$-ESR/hr, using non-heparinized Micro-Ht-tubes at $20^{\circ}C$, was determined in 35 healthy Korean native goats. The average PCV was $30.6{\pm}1.4ml/100ml$. The observed ESR values averaged $6.8{\pm}1.7%$ and the corrected ESR values to the standard PCV of 31ml/100ml averaged $6.5{\pm}1.2%$. From these results, the angled capillary tube method was found to be desirable ESR test of goat blood in which EDTA-blood is filled in nonheparinized Micro-Ht-tubes held at an angle of 45 degrees for an hour at $20^{\circ}C$.

• Bulletin of the Korean Chemical Society
• /
• v.27 no.9
• /
• pp.1429-1432
• /
• 2006

Polyaromatic hydrocarbons were separated by a capillary supercritical fluid chromatographic (SFC) column and detected by a UV detector at the wavelength of 280 $\mu$m. The temperature-controlled restrictor was designed for UV detection. The temperature-controlled restrictor is a 20 cm length of deactivated fused silica of 7 mm i.d. which is held right after UV detector of the capillary SFC. The temperature of the restrictor will control the flow rate of the supercritical carbon dioxide mobile phase through the capillary column in SFC. Thus as the pressure in the column is increased from 1500 psi to 4000 psi during a pressure program, the temperature of 7 $\mu$m fused-silica tube can be varied from 100 to 350 ${^{\circ}C}$ to maintain a constant flow rate.

• Journal of Power System Engineering
• /
• v.17 no.6
• /
• pp.47-53
• /
• 2013

The article focuses on the Temperature characteristics inside single loop oscillating heat pipe (OHPs). In this paper, heat pipe is experimentally studied thereby providing vital information on the parameter dependency of their thermal performance. The impact depiction has been done for the variation of tube model of the device. OHPs are made of copper capillary tubes of outer diameter 6.25 mm, inner diameter 4 mm heated by constant temperature water bath cooled by ambient temperature. Using four types of OHPs of copper capillary tubes length of 1500mm and HP length 650mm inside tubes working fluid is R-22 Pressure 8 bar and mass 34g,32g,28g,16g. The results indicate a strong influence of filling ratio on the performance.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.14 no.9
• /
• pp.749-755
• /
• 2002

In order to develop a multi-type heat pump system with two indoor units of non-uniform capacities, the optimum refrigerant circuit was developed using capillary tubes. The refrigerant circuit was composed of four main parts, a heating circuit, a cooling circuit, a by-pass circuit and a balance circuit. The system characteristics of multi-type heat pump was investigated through the rating test and the reliability test, using the multi-type psy-chrometric calorimeter. The results of the rating test showed that the capacity of the multi-type heat pump was about 93% of the design value. In particular, the capacity of cooling single mode was about 13% higher than the design value, and the capacity of heating multi mode was about 5% higher than the design value. The reliability of the multi-type heat pump was verified by various reliability tests (overload, extension tube, freeze up, under/over charging, sweat, flood back). The optimal amount of refrigerant charge and compressor capacity were determined from the present work.

• Journal of the Optical Society of Korea
• /
• v.10 no.3
• /
• pp.99-104
• /
• 2006

We introduce a novel contrast mechanism for imaging superparamagnetic iron oxide (SPIO) nanoparticles (average diameter ${\sim}100nm$) using magneto-motive optical Doppler tomography (MM-ODT), which combines an externally applied temporally oscillating high-strength magnetic field with ODT to detect the nanoparticles flowing through a glass capillary tube. A solenoid cone-shaped ferrite core extensively increased the magnetic field strength ($B_{max}=1\;T,\;{\Delta}|B|^2=220T^2/m$) at the tip of the core and also focused the magnetic force on targeted samples. Nanoparticle contrast was demonstrated in a capillary tube filled with the SPIO solution by imaging the Doppler frequency shift which was observed independent of the flow rate and direction. Results suggest that MM-ODT may be a promising technique to enhance SPIO nanoparticle contrast for imaging fluid flow.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.22 no.1
• /
• pp.113-121
• /
• 1998

The performance evaluation of a residential split system inverter air-conditioner has been conducted analytically and experimentally at different system operating conditions. A simulation program for modelling an air-conditioning system which consists of a compressor, a condenser, a capillary tube, an evaporator and related attachments was developed on the basis of the Oak Ridge heat pump design model, MARK III. The accuracy of the simulation results for the compressor frequencies of 32, 68 and 79 Hz for the residential split system inverter air-conditioner has been estimated by comparing calculation results to the experimental data and parametric study has been performed to investigate the effect of design parameters and operation conditions on the system performance.

• 유체기계공업학회:학술대회논문집
• /
• 2006.08a
• /
• pp.557-560
• /
• 2006

The contact angle of a meniscus and a droplet can be controlled by using electrowetting phenomena. We investigated the dynamic aspect of electrowetting for an oil-electrolyte interface formed inside a closed glass tube. A step input voltage is applied and the subsequent motion of the interface is recorded by a high-speed camera. A kind of capillary instability is observed near the three-phase contact line, which could degrade the reliability of device utilizing electrowetting such as electrowetting liquid lens. The dynamics of interface motion for different input voltages and the fluid viscosities are analyzed and discussed based on the experimental results.