• Journal of the Korean Chemical Society
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• v.17 no.5
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• pp.353-356
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• 1973

A unique method of destructive analysis has been developed for the study of gaseous impurities in minerals. Samples are crushed in a high vacuum sample system of a research mass spectrometer. This is done by means of a suitably designed crusher which is incorporated in the inlet system of the instrument. Crusher elements are constructed of tungsten carbide. The mass spectrometer used for this preliminary study has a detection sensitivity of about $10^{-10}cc$at STP. In a study of rhodolite garnets obtained from near Lavonia, Georgia, U.S.A., the gases$H_2$, $O_2$, $H_{2}O$, $CO_2$, CO, and $CH_4$have been identified and their composition determined.

• Solar Energy
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• v.15 no.3
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• pp.91-103
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• 1995

Non-gray radiation with convection in the entrance region of a smooth tube is numerically investigated. The fluid is a mixture of carbon dioxide, water vapor, and nitrogen to simulate combustion products of propane. The flow is assumed to be laminar and hydrodynamically and thermally developing. The P-1 approximation is used to simplify the radiative transfer equation and the exponential wide band model is adapted to model the spectral absorption coefficients of non-gray gas mixture. The bulk mean temperature and Nusselt number variation along the tube axis are shown for several inlet and wall temperature pairs to show the effect of temperature on the heat transfer characteristics. Nusselt numbers for simultaneously developing flow are compared to those for thermally developing flow. In addition, the effect of the mole fraction of the non-gray gases on convective and radiative Nusselt numbers is investigated.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.635-639
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• 2009

Experimental work was carried out to study the combustion kinetics of the Indian coal-char in the varying mixture of carbon dioxide-oxygen ($CO_2-O_2$). The coal sample was pulverized and sieved to less than 58 microns and charred using volatile furnace by passing the nitrogen gas. The experiments were carried out using the Thermo Gravimetric Analyzer (TGA-50) at CPRI, Bangalore, different proportions of ($CO_2-O_2$) gas was allowed in to the TGA-50 (80-20, 60-40, 40-60, 20-80) mole basis were used to study the combustion kinetics of coal Isothermally, kinetic parameters like Activation energy (E) and the pre-exponential factors (A) are calculated using the unification approach and modified Arrhenius equation.

• Journal of Oral Medicine and Pain
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• v.23 no.3
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• pp.249-255
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• 1998

Mucoceles of the minor salivary glands are the most common cystic lesions affected the oral mucosa. They are believed to be the result of trauma to the salivary duct caused, for example, by biting the lip, cheek, or tongue. Surgical excision has been the most common treatment for these lesions, but occasional recurrences develop after excision because surgical trauma may damage the surrounding minor salivary glands Although various alternative nonsurgical approaches, such as steroid infection, application of gamma-linolenic acid, have also been reported, they are not used routinely, Lasers, particularly the carbon dioxide laser, have been used in the management of mucoceles. Although this treatment requires specialized equipment. Cryotherapy is another effective nonsurgical method for treating mucoceles. Clinically, cryotherapy has primarily been applied to the treatment of leukoplakia and hyperplastic, granulomatous, vascular, and pigmented lesions. Limited information, however, is available on the application of cryotherapy in salivary gland lesions, including mucoceles. A simple and easy cryotherapy to treat a mucocele on the lower lip is described. A 25 years old female patient with a mucocele on the lower lip was treated by direct application of liquid nitrogen with a cotton swab. The lesion was exposed to 4 or 5 cycles composed of freezings of 10-30 s and thawings of double the freezing times. No anesthesia was required. The lesion nearly disappeared without scar 10 days after the cryotherapy. Cryotherapy has become an established nonsurgical method, characterized by its simple application, therapeutic effectiveness, painless during the procedure and low incidence of secondary infection and hemorrhage.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.6
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• pp.120-127
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• 2005

An IDI diesel engine used to agricultural tractors was fueled with $20\%$ biodiesel fuel(BDF 20) in excess of 300 hours. Engine dynamometer testing was completed at regularly scheduled intervals to monitor the engine performance and exhaust emissions. The engine performance and exhaust emissions were sampled at 1 hour interval for analysis. The combustion variation such as the combustion maximum pressure and the crank angle at this maximum pressure was not appeared during long-time dynamometer testing. Also, BSFC with BDF 20 resulted in lower than with diesel fuel. Since the biodiesel fuel used in this study includes oxygen of about $11\%$, it could influence the combustion process strongly. So, BDF 20 resulted in lower emissions of carbon monoxide, carbon dioxide, and smoke emissions without special increase of oxides of nitrogen than diesel fuel. It was concluded that there was no unusual deterioration of the engine, or any unusual change in exhaust emissions from using the BDF 20.

• Journal of Environmental Health Sciences
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• v.26 no.4
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• pp.134-140
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• 2000

The increase in traffic is a worldwide phenomenon. In Korea, it has been increased by 20% per annual in recent 1990’s and approximately 10 millions cars had been registered until 1997. This traffic could easily affect and contribute the local outdoor air quality(QAQ) concerned. The QAQ in highway in one of the examples and the subject in this study. The seoul tollgate located at the north-end of Keypngbu Highway was selected for the study. In case of highway tollgate, the local air pollution could be directly affected by the traffic to approach, wait and start the tollgate. Nitrogen dioxide (NO$_2$) concentration exceeded the EAQS(Environmental Air Quality Standards), but overall indoor air quality was a little better than the outdoor air quality. The measured TSP concentration was much higher than that of the EAQS. To apply a management to a air quality problem of Seoul tollgate, it was predicted air quality with traffic volume and weather condition. It was calculated NO$_2$ emission with traffic volume and predicted in and out of booth by CALINE3 at the Seoul tollgate. To make a comparison between measured and predicted concentration, the prediction was good. It was shown that NO$_2$ concentration was high in the morning at the from Seoul direction and in the evening at the to Seoul direction. it was thought that NO$_2$ concentration variation was reflected according to the traffic volume.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.4 no.1
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• pp.13-16
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• 2003

We implanted $N^+ion$ into TiO$_2$/Ti substrates with 70 keV by varying dose of 0, 2, 5, and $10{\times}10^{17}/cm$^2$$. In addition, $N^+ion$implanted TiO$_2$ specimens were annealed at $600^{\circ}C$ for 2 hours in Atmosphere. We investigated the color evolution, surface roughness, and hardness of specimens with doses. We report that the color changed from white into dark-yellow as dose increased. ion implanted surfaces became smooth when they were annealed. Moreover, hardness increased up to 10% when we annealed ion implanted TiO$_2$. Our results imply that we may enhanced titanium color and surface hardness.

• Journal of the Korean Society of Combustion
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• v.10 no.4
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• pp.33-40
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• 2005

The propagation rates of advancing and retreating non-premixed edge flames in a slot-jet counterflow were measured as a function of strain rate for varying jet spacing, mixture strength, stoichiometric mixture fractions $(Z_{st})$ and Lewis numbers (Le). Methane and propane fuels were tested and nitrogen and carbon dioxide were used as inerts. As results, we could identify igniting fronts, retreating fronts, two total extinction limits, and short-length edge flames. A burner separation affected to a low extinction limit only. Regimes for advancing and retreating edges together with total extinction were mapped in terms of normalized flame thickness and heat loss factor for $CH_4/O_2/N_2$ mixtures. Edge flames for $Z_{st}$ > 0.5 behaved like a stronger mixture while for $Z_{st}$ < 0.5 showed deteriorated feature, because of relative locations of a non-premixed flame and intermediate species such as CO and $H_2$. Furthermore, due to the relative importance of heat loss, propagating speeds of edge flames were significantly enhanced in $CH_4/O_2/CO_2$ mixtures (Le < 1) demonstrating increasing stability limits. However $C_3H_8/O_2/N_2$ mixtures (Le > 1) showed opposite result.

• Transactions of the Korean Society of Automotive Engineers
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• v.12 no.1
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• pp.32-38
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• 2004

To evaluate the durability of direct injection diesel engine using biodiesel fuel, a small D. I. diesel engine was operated on a blend(BDF 20) of 20％ biodiesel fuel and 80％ diesel fuel for 200 hours. Engine dynamometer test was performed at a load of 90％ and a speed of 1900 rpm to monitor the engine performance and exhaust emissions. Engine performance parameters and exhaust emissions were sampled at 1 hour interval for analysis. The combustion maximum pressure and the crank angle at this maximum pressure as a combustion variation factor were considered to study the combustion characteristics of BDF 20 in diesel engine during durability test. As the results, the standard deviations and errors of combustion variation factors on BDF 20 were very little and combustion characteristics were very stable during the durability test. BDF 20 resulted in lower emissions of carbon monoxide, carbon dioxide, and smoke emissions with special increase of nitrogen oxides compared to diesel fuel. There was no also unusual change in engine oil composition from using BDF 20. Most of engine parts were clean and showed little wear, but soots were detected around the hole of fuel injector when BDF 20 was used in direct injection diesel engine for 200 hours.

• Proceedings of the Korea Technical Association of the Pulp and Paper Industry Conference
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• 2006.06b
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• pp.279-284
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• 2006

Activated carbon is proposed as a new application of wastepaper recycling other than the paper-making. Waste kraft bag is considered to be a suitable raw material for activated carbon because of its low ash content. Small pellets of wastepaper squeezed out from the continuous kneader were carbonized in a nitrogen atmosphere and activated using carbon dioxide. The BET specific surface areas of activated carbon prepared from waste kraft bag was $1,285m^{2}/g$, which is higher than commercially available activated carbons. The activated carbon prepared from wastepaper has a well-developed porous structure, particularly in mesopore and macropore ranges. As a result, activated carbon with iodine adsorption capacity of 1,400 mg/g was obtained from waste kraft bag. In this paper, adsorption amount of Bisphenol A (BPA) was determined to investigate adsorbability of activated carbon from waste kraft bag. Adsorption measurements were on solutions ranging from $0.1{mu}g/L\;to\;100mg/L$. The activated carbon from waste kraft bag gave higher BPA adsorbabilities over a wide range, compared with commercially available activated carbons.