• Journal of Oral Medicine and Pain
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• v.22 no.1
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• pp.45-63
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• 1997

A Study was conducted to examine the nature and extent of psychological differences among diagnostic subgroups of temporomandibular disorders(TMD) patients and to whether psychological distress acts as a precipitator for TMD or is only an incidental consequence of the discomfort and frustrations presented by the disorder. Ninty six TMD patients and ninty seven non-TMD dental patients were included for the study as an experimental group and control group. TMD patients were classified into subgroups according to their primary pain sites and labeled as: 1) Myogenous TMD group; 2) Arthrogenous TMD group; 3) Mixed TMD group. After Hilkimo indices were rated from patient history and clinical examination, levels of psychological distress were measured using SRRS (Social Readjustment Rating Scale) and MMPI (Minnesota Multiphasic Personality Inventory). Outcomes from Helkimo indices, SRRS, and MMPI were assessed in terms of diagnostic subgroups and pain chronicity. The relationship between SRRS and MMPI scores were also assessed. The results were as follows : 1. The TMD patients showed higher frequencies of AiII, DiII, and DiIII of Helkimo indices than those in the control subjects. 2. The chronic TMD patients showed lower frequencies of DiII and DiIII of Helkimo indices than those in the acute group. 3. The arthrogenous TMD group showed higher frequencies of DiII and DiIII of Helkimo indices than those in the myogenous TMD group. 4. The TMD patients showed higher SRRS mean score than that in the non-TMD patients. 5. The SRRS mean score was highest in the myogenous TMD group and lowest in the arthrogenous TMD group. 6. The chronic TMD patients showed higher SRRS mean score than the acute TMD group. 7. The TMD patients showed higher MMPI mean scores on the Hs, D, Hy, and Pt scales than those in the non-TMD patients. 8. The MMPI mean scores on th Hs, D, and Hy scales were higher than of other MMPI scales in the TMD patients as well as in the myogenous and the mixed TMD group and they showed 1-3-2(Hs, -Hy, -D.) profile pattern, conversion "V". 9. The MMPI mean scores on the Hs and Hy scales were higher in all subgroups of TMD patients than non-TMD patients. 10. Although there were no significant differences in the MMPI mean scores on all the scales between the acute and the chronic groups of all TMD patients, the chronic myogenous TMD group showed higher MMPI mean scores on the Hs, Hy, Pa, and Pt scales than the acute myogenous TMD group. 11. There were positive correlationships between SRRS score and each MMPI scores on the Hs and Hy scales.Hy scales.

• Korean Chemical Engineering Research
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• v.48 no.2
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• pp.268-274
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• 2010

Emission of heavy metals as hazardous air pollutants has been focused with tightening regulatory limits due to their hazardousness. Measurements and characteristic investigations of heavy metals emitted from a commercial power plant burning anthracite coal have been carried out. The plant consists of a circulating fluidized bed combustor, a cyclone, a boiler and an electrostatic precipitator(ESP) in series. Dust and gaseous samples were collected to measure main heavy metals including gaseous mercury before ESP and at stack. Dust emissions as total particulate matter (TPM), PM-10 and PM-2.5 at inlet of ESP were very high with 23,274, 9,555 and $7,790mg/Sm^3$, respectively, as expected, which is much higher than those from pulverized coal power plants. However TPM at stack was less than $0.16mg/Sm^3$, due to high dust removal efficiency by ESP. Similarly heavy metals emission showed high collection efficiency across ESP. From particle size distribution and metal enrichment in sizes, several metal concentrations could be correlated with particle size showing more enrichment in smaller particles. Mercury unlike other solid metals behaved differently by emitting as gaseous state due to high volatility. Removal of mercury was quite less than other metals due to it's volatility, which was 68% only. Across ESP, speciation change of mercury from elemental to oxidized was clearly shown so that elemental mercury was half of total mercury at stack unlike other coal power plants which equipped wet a scrubber.

• Korean Chemical Engineering Research
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• v.57 no.4
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• pp.461-468
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• 2019

Demand for improving dust removal efficiency in coal power plants and the dust removal requirement to the level of capturing fine particulate matter and ultrafine particles have been increasing. While bag filter and electrostatic precipitator (ESP) are typically used for dust removal in the processes operating at atmospheric pressure, metal filters or ceramic filters are employed for dust which is produced at high temperature/pressure system as in coal gasification. For dust removal at the high temperature/pressure conditions, two metal filters of five compressed/sintered layers were manufactured and applied to analyze the dust removal characteristics. Manufactured metal filters exhibited more than 99% dust removal efficiency on coal gasification fine particulates in mass basis. To evaluate the fine particulate removal efficiency of less than $2.5{\mu}m$, JIS standard fine sample was used and confirmed the removal efficiencies of 97% and 70~82% on the fine particulates of $1{\sim}2.5{\mu}m$ size range. For the size range of less than $1{\mu}m$, dust removal efficiency of manufactured metal filters significantly degraded with smaller particle size. Improving methods are proposed to overcome the limitations in applying to fine dust of less than $1{\mu}m$.

• Korean Journal of Soil Science and Fertilizer
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• v.8 no.2
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• pp.89-96
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• 1975

The experiment was carried out to investigate the chemical properties of cement kiln dusts, abundantly produced from cement industry as a byproduct, and their effectiveness on rice yield. The field experiment was conducted on the acid paddy soil developed on basalt at Dongsong-Myon, Chulwon-Kun, Gangwon-Do. Two kinds of cement kiln dusts were used ; By Pass (BP) collected from the suspension preheater and Electric Precipitate (EP) from the cottrell electric precipitator. The levels of cement kiln dust applied were 100kg/10a, 200kg/10a and 300kg/10a, and the recommended variety "Nong Back" was adopted for this experiment. The results obtained are summarized as follows ; 1. The component of cement kiln dusts seems to be quite suitable for liming material. BP has 55% alkalinity, 41.7% of soluble calcium, 9.8% of soluble magnesium and 4.5% of water soluble silicate, while EP has 53.5% alkalinity, 41.7% soluble calcium, 8.3% soluble magnesium and 1% water soluble silicate. 2. The relative effectiveness of cement kiln dust in the soil will be superior due to very fine particle size. EP pass through completely 270 mesh screen, and 95% of BP pass through 150 mesh screen, 68% passing 270 mesh. 3. BP application at the rate of 100kg/10a increased 21% of rice yield as compared with control and EP 15%. It was observed that the affected yield components were increased panicle number per hill, grain number per panicle and 1,000 grains weight. 4. The application of optimum amount (100kg/10a) of cement kiln dusts accelerated the uptake of nutrients by rice plant and increased rice yield. However, the excess amounts (200kg/10a, 300kg/10a) of cement kiln dusts retarded the uptake of nutrients from soil.

• Journal of Korean Society of Environmental Engineers
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• v.39 no.8
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• pp.449-455
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• 2017

Process input data including material and energy, process output data including product, co-product and its environmental emissions of the reference and target processes were collected and analyzed to evaluate the process performance. Environmentally problematic input/environmental emissions of the manufacturing processes were identified using these data. Significant process inputs contributing to each of the environmental emissions were identified using multiple regression analysis between the process inputs and environmental emissions. Optimum combination of the end-of-pipe technologies for treating the environmental emissions considering economic aspects was made using the linear programming technique. The cement manufacturing processes in Korea and the EU producing same type of cement were chosen for the case study. Environmentally problematic input/environmental emissions of the domestic cement manufacturing processes include coal, dust, and $SO_x$. Multiple regression analysis among the process inputs and environmental emissions revealed that $CO_2$ emission was influenced most by coal, followed by the input raw materials and gypsum. $SO_x$ emission was influenced by coal, and dust emission by gypsum followed by raw material. Optimization of the end-of-pipe technologies treating dust showed that a combination of 100% of the electro precipitator and 2.4% of the fiber filter gives the lowest cost. The $SO_x$ case showed that a combination of 100% of the dry addition process and 25.88% of the wet scrubber gives the lowest cost. Salient feature of this research is that it proposed a method for identifying environmentally problematic input/environmental emissions of the manufacturing processes, in particular, cement manufacturing process. Another feature is that it showed a method for selecting the optimum combination of the end-of-pipe treatment technologies.