• Journal of Institute of Convergence Technology
• /
• v.9 no.1
• /
• pp.13-19
• /
• 2019

The purpose of this study is to suggest a new method to determine a combustion phase (start of combustion and end of combustion) using a combustion pressure data. Unlike previous research method that used heat release amount, the difference between the combustion pressure measured in the combustion chamber and the motoring pressure was used to determine the combustion phase. This research was conducted using a single-cylinder diesel engine with a compression ratio of 17.7. The test was conducted under various injection timing. The newly proposed method showed high accuracy in combustion mode with early injection, as well as the conventional combustion mode. It is expected that this method will be used to study new combustion strategies such as HCCI (homogeneous charge compression ignition) and RCCI (reactivity controlled compression ignition) that are applying early injection strategies as well as existing combustion modes.

• Tribology and Lubricants
• /
• v.26 no.6
• /
• pp.336-340
• /
• 2010

Ultrasound thermography detects defects by radiating 20 ~ 30 kHz ultrasound waves to the samples and capturing the heat generated from the defects with the use of an infrared thermographic camera. This technology is being spotlighted as a next-generation NDE for the automobile and aerospace industries because it can test large areas and can detect defects such as cracks and exfoliations in real time. The heating mechanism of the ultrasound vibration has not been accurately determined, but the thermomechanical coupling effect and the surface or internal friction are estimated to be the main causes. When this heat is captured by an infrared thermographic camera, the defects inside or on the surface of objects can be quickly detected. Although this technology can construct a testing device relatively simply and can detect defects within a short time, there are no reliable data about the factors related to its detection ability. In this study, the ultrasound thermography technique was used to manufacture gasoline and diesel engine piston specimens, and nondestructive reliability tests to verify the applicability and validity of the ultrasound thermography technique.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.1845-1850
• /
• 2003

The underground utility tunnels are important facility as a mainstay of country because of communication developments. The communication and electrical duct banks as well as various utility lines for urban life are installed in the underground utility tunnel systems. If a fire breaks out in this life-line tunnel, the function of the city will be discontinued and the huge damages are occurred. In order to improve the safety of life-line tunnel systems and the fire detection, the behaviors of the fire-induced smoke flow and temperature distribution are investigated. In this study we assumed that the fire is occurred at the contact or connection points of cable. Numerical calculations are carried out using different velocity of ventilation in utility tunnel. The fire source is modeled as a volumetric heat source. Three-dimensional flow and thermal characteristics in the underground tunnel are solved by means of FVM (Finite Volume Method) using SIMPLE algorithm and standard ${\kappa}-{\varepsilon}$ model for Reynolds stress terms. The numerical results of the fire-induced flow characteristics in an underground utility tunnel with different velocity of ventilation are graphically prepared and discussed.

• The Plant Pathology Journal
• /
• v.24 no.3
• /
• pp.328-336
• /
• 2008

Out of various fungi and bacteria tested for inhibition of Tobacco mosaic virus(TMV) infection using Nicotiana tabacum cv. Xanthi-nc, a bacterial isolate JB-l, identified as Pseudomonas putida had a strong direct inhibitory activity against the TMV infection. Its systemic or indirect activity was also noted at more than a half level of the direct control efficacy. Disease severity was reduced significantly in the susceptible tobacco N. tabacum cv. NC 82 by the treatment of the bacterial culture filtrate, somewhat more by the pretreatment than by simultaneous treatment, probably by inhibiting the TMV transmission and translocation in the plants, showing negative serological, which responses in the viral detection by DAS-ELISA. TMV-inhibitory substances from P. putida JB-1 were water-soluble, stable to high temperature(even boiling), and to a wide range of pH. As proteinase K nullified their antiviral activity, the TMV inhibition activity of P. putida may be derived from proteinaceous materials. In electron microscopy, TMV particles treated with the JB-1 culture were shown to be shrunken with granule-like particles attached on them. All of these aspects suggest that P. putida JB-1 may be developed as a potential agent for the control of TMV.

• Journal of Food Hygiene and Safety
• /
• v.9 no.4
• /
• pp.221-228
• /
• 1994

The quantitative detection of ochratoxin A (OT-A) in the traditional fermented foods were investigated to develop the analytical procedures, Enzyme-Linked Immunosorbent Assay(ELISA) and Chemiluminescence Immunoassay(CIA). Products used were divided into two groups: the first was the home-made 13 Doenjang, 12 Kanjang, and 14 Gochujang; and the second the traditional commercial products, 17 Deonjang and 11 Kanjang, which collected throughout the country. The standard curve for the quantitative determination of OT-A showed that the sensitivities in ELISA and CIA were upto the level of 20 pg/assay, and that the OT-A recovery rates were appeared to be more than 90%. The residual OT-A in the home-made products were 7.1$\pm$3.7 ng/g for Deonjang, 2.1$\pm$4.1 ng/g Kanjang were found in the traditional commercial products. Residual OT-A in the home-made products was comparatively far less than that of the traditional commercial products. At heat stability test of OT-A in the traditional fermented foods was found to be stable even at 121$^{\circ}C$ for 120 min.

• Journal of Environmental Science International
• /
• v.7 no.5
• /
• pp.615-622
• /
• 1998

The volatile organic compounds(VOCs) emitted from raw garlic and Kimchee were analyzed with thermal desorption or purge ＆ trap/gas chromatography/mass selective detection method. Very offensive compounds such as methyl allyl sulfide, dimethyl sulfide, dimethyl disulfide, diallyl sulfide, methyl allyl disulfide, diallyl disulfide and dimethyl trisulfide were detected, and among them, dimethyl disulfide and dimethyl trisulfide were confirmed to be generated during the precocity of Kimchee or emitted from the stuff of Kimchee other than the garlic. Malodorous compounds emitted from the garlic or Kimchee were detected in the breath of a Korean and the refregirator keeping Kimchee. It was confirmed that the disufides emitted from the garlic or Kimchee were major components of offensive odor in the alveolar air and the refregirator. It was clarfied that heat process is very effective to reduce odorous VOCs in garlic or Kimchee.

• Journal of the Korean Society for Heat Treatment
• /
• v.7 no.3
• /
• pp.155-159
• /
• 1994

As Cr-Mo-V steels have excellent mechanical and creep properties at elevated temperatures, they are extensively used in power plants. However, the steam turbine components are supposed to have suffered material degradation during long-term service at elevated tenperatures. Many efforts have been made to assess the safety and residual life of these components by means of non-destructive methods such as plastic replication, hardness and electric resistance techniques. Recently, a parameter correlating hardness changes during long-term heating to those during creep was introduced and it was named 'G parameter'. The electric resistivity as well as hardness are affected by damage accumulation, but there have been no efforts to correlate G parameter to resistivity changes. In this study, relationship between G parameter and changes in electric resistivity was investigated using artificially aged Cr-Mo-V steel. It is well understood that G parameter can be applied to electric: resistance techmique.

• Journal of the Korean Society for Heat Treatment
• /
• v.24 no.3
• /
• pp.140-143
• /
• 2011

In this work, Ga doped ZnO (GZO) films were prepared by radio frequency (RF) magnetron sputtering without intentional substrate heating on glass substrate and then the effect of the intense electron irradiation on structural and electrical properties and the NOx gas sensitivity were investigated. Although as deposited GZO films showed a diffraction peak for ZnO (002) in the XRD pattern, GZO films that electron irradiated at electron energy of 900 eV showed the higher intense diffraction peaks than that of the as deposited GZO films. The electrical property of the films are also influenced with electron's energy. As deposited GZO films showed the three times higher resistivity than that of the films irradiated at 900 eV In addition, the sensitivity for NOx gas is also increased with electron irradiation energy and the film sensor showed the proportionally increased gas sensitivity with NOx concentration. This approach is promising in gaining improvement in the performance of thin film gas sensors used for the detection of hazard gas phase.

• Fire Science and Engineering
• /
• v.24 no.2
• /
• pp.178-184
• /
• 2010

In this study, a smoke or a heat which occurs by a fire is perceived by wireless detector, this signal is transmitted to the receiving device by the wireless installation which is not the wire device and wire/wireless integration system which sends this signal to main server via wire system is proposed. In addition wireless heat/smoke detector, wireless module, firmware and wire/wireless integration controller were developed and for verifying regarding the efficiency and applicability of wire/wireless installation actual place application experiment was really accomplished with a transmission tower, a multipurpose building, and a station etc of the subway. The experimental result, it could operate the system which is proposed normally with all experimental object ones and, future actual place application possibility could verify.

• Journal of the Korean Society of Safety
• /
• v.29 no.3
• /
• pp.20-27
• /
• 2014

Cooling equipment is the frequent occurrence of fire despite the absence of the heating element. National fire statistics in 2013 show that a total of 263 fires occurred in the cooling equipment and the number of electric fan has 145 fire cases. This is accounted for 55.1% of the whole. Electric fan is the electrical appliance that the heat is generated on the winding wire and the iron core. If such characteristic is not controled properly, fire would break out at the electric fan. also there is a gap filled with an insulator between connection terminals of the capacitor in the electric fan. But in case that the gap on the capacitor is covered with some conductive material such as dust, there would be a fire as well caused by electrical heating locally. Although many studies related with those have been conducted, electric fan fire is continuously occurred. In this study, thermal characteristics and current signal in various conditions such as the heat generation of windings including iron cores of the motor and the dielectric breakdown of terminals on the capacitor connected to the motor were detected. In order to measure the maximum temperature, "third level" wind velocity button was pushed and the time selection switch to "continuation" was set. Analyzed data would be available for the fire safety of the electric fan.