모래/폴리스티렌 유동층에서 입자 혼합에 관한 연구

신용섭 경성대학교 환경문제연구소 2000 環境硏報 Vol.10 No.1

The minimum fluidization velocities of sand/polystryrene mixture in a fluidized bed were measured according to variation of mixing ratio. Particle concentration distributions in the bed were also measured with mixing ratio and superficial air velocity. The mixing index was defined and calculated from the measured particle concentration distribution. As mixing ratio of the sand was increased, voidage of the fixed bed showed trend of concave curve and voidages at minimum fluidization conditions also behaved as those of fixed bed. Based on the measured results, it could be concluded that the minimum fluidization velocities were determined by the components which had high mixing ratio. It was also evident that sand particle took a role of jetsam and polystyrene particle took a role of floatsam and their behavior were independent of mixing ratio and superficial air velocity. As mixing ratio and superficial air velocity were increased, particle concentration distribution in the middle section of the bed was improved. However, particle concentration distributions near the bottom of the bed and especially, near the top section were not improved. The mixing index of the bed was increased with the excess air velocity.

先加力 후 補修-補强한 鐵筋콘크리트 壓縮部材의 構造特性에 관한 實驗的 硏究

신용석,최진석,김판선,조철희,손순채,김정섭 대한건축학회 2003 대한건축학회 학술발표대회 논문집 - 계획계/구조계 Vol.23 No.2(구조계)

This study examined the Stress and structural characteristics of reinforced concrete compressive member repair and strengthening by CFS and GFS after pre-loading. The following results were obtained. The results of compressive testing by the kind of fiber suggested that: In CFS, Specimen increased by about 26.9% and strengthening after pre-loading, by about 111.8%, compared with after strengthening, In GFS, Specimen increased by about 69.0% and repaired and models after pre-loading, by about 76.7%, compared with after strengthening. In the compressive testing, strengthen with CFS-Specimen showed a brittle fracture and strengthen with GFS-Specimen represented ductile fracture. More increasing in stress of Specimen, and repair and Strengthening specimen after pre-loading than loading specimen after strengthening suggested the strengthen effect of fiber.

도시하수 슬러지의 유동층 연소 특성

신용섭 慶星大學校 環境問題硏究所 1995 環境硏報 Vol.5 No.1

Under the several operating conditions, combustion characteristics of sewage sludge(waste activated sludge) were investigated using fluidized bed incinerator. Moisture content of sewage sludge was very high, about 98%, and had heating value of 3,200 kcal/kg dry solid. Before being burnt out, sludge was conditioned with polymer, dewatered and dryed up to moisture content of 14.7%. As the operating conditions were relatively mild and varied in small range, combustion efficiencies were detected very high values of above 99% and almost insensitive to changes of operating conditions. Bed temperature showed very uniform distributions in fluidized bed and temperature decreased along the freeboard height during the whole range of operations. Especially, temperature of just above bed surface showed maximum value by the combustion of gasified volatile matter. Temperatures in the freeboard region increased as bed temperature and superficial air velocity increased. When superficial air velocity increased elutriation rate of fine particles increased by the increased. When superficial air velocity increased elutriation rate of fine particles increased by the increment of sturation carrying capacity of flue gas. Thus, elutriation loss of combustible was determining factor of combustion efficiency.

고체 촉매를 이용한 대두유와 폐식용유의 에스테르화

신용섭 한국환경과학회 2004 한국환경과학회지 Vol.13 No.1

Esterification of soybean oil with methanol was investigated. First of all, liquid-liquid equilibriums for systems of soybean oil and methanol were measured at temperatures ranging from 40 to 65°C. Profiles of conversion of soybean oil with time were determined from the glycerine content in reaction mixtures for the different kinds of catalysts, such as NaOH, CaO, Ca(OH)₂, MgO, Mg(OH)₂, and Ba(OH)₂. The effects of dose of catalyst, cosolvent and reaction temperature on final conversion were examined. Esterification of waste vegetable oil with methanol was investigated and compared to the case of soybean oil. Solubility of methanol in soybean oil was substantially greater than that of soybean oil in methanol. When the esterification reaction of soybean oil was catalyzed by solid catalyst, final conversion was strongly dependent on the alkalinity of the solid catalyst, and increased with the alkalinity of the metal. Hydroxides from the alkali metals were more effective than oxides. When Ca(OH)₂ was used for the esterification catalyst, maximum value of final conversion was measured at dose of 4%. When CHCl₃ as a cosolvent, was added into the reaction mixture of soybean oil which catalyzed by Ba(OH)₂, maximum value of final conversion was appeared at dose of 3%. When waste vegetable oil was catalyzed by NaOH and solid catalysts, high final conversion, over 90%, and fast reaction rate were obtained.

글로우 방전을 이용한 이산화탄소의 전환특성

신용섭,송승훈,곽동주 慶星大學校 1998 論文集 Vol.19 No.2

In this study, the characteristics of CO₂conversion and glow discharge were investigated using glow discharge plasma reactor with a parallel copper electrode system. A pure CO₂ gas was used for the carrier gas under gas pressure of 10∼80 torr in a glow discharge. For glow discharge, discharge current was increased with the increase of discharge voltage. In the case of constant discharge voltage, the discharge current tend to increase with the decreasing of gas pressure. Using pure CO₂only, the CO₂conversion was increased with the increase of discharge power and the decreased of gas pressure. The maximum CO₂ conversion was 28% at 10 torr, 598 W, 902.4V. Energy yield was decreased with the increase of discharge power and discharge voltage. Also, the concentrations of CO₂and O₂in the produced gas were slightly increased with the increase of CO₂ conversion.

염색체 미세해부에 의한 신세포암 세포주 Caki-1의 표지 염색체 분석

신재섭,박수연,전용혁,박선화 大韓泌尿器科學會 1998 Korean Journal of Urology Vol.39 No.3

流動層 燒却盧에서 段階的 燒却法에 의한 都市下水슬러지의 燒却

신용섭,안선국 慶星大學校 環境問題硏究所 1997 環境硏報 Vol.7 No.1

The characteristics of combustion and pollutant emission from a fluidized bed incinerator, in which waste activated sludge from municipal sewage treatment plant was burnt on the staged combustion modes, were investigated under the several operating conditions. The dried waste activated sludge with the moisture content of 4.5% and the heating value of about 4,200 kacal/kg dry solid was used in this study. With the variation of operating paramenters, such as bed temperature, superficial air velocity, and excess air ratio, temperature distributions in the incinerator and characteristics of ash drain rates and pollutant emission from the incinerator were measured. As the dried sludge had high volatile content, the maximum temperature appeared at upper region of fluidized bed surface in measured temperature distributions and the axial position of maximum temperature moved up with increase of superficial air velocity. The measured combustible contents of fly ash and bottom ash were lower than 3% and 0.4%, respectively. Thus, combustion efficiencies showed very high values of over 99.6% and were not severly affected by the variations of bed temperature and superficial air velocity. However, as the excess air ratio was increased, combustion efficiencies were decreased by the temperature drop in the freeboard region. The concentration of Co in exhausted gas was increased substantially with the increase of superficial air velocity which could reduce residence time of devolatilized gas in the freeboard. However, concentrations of SO₂and No?? were decreased slightly with the increase of superficial air velocity.

유동층 소각로에서 모래/폴리스티렌 혼합 특성에 관한 연구

신용섭 慶星大學校 1993 論文集 Vol.14 No.2

As a first stage of studies on the development of a fluidized bed incinerator for municipal solid waste, the axial mixing characteristics of polystyrene beads and sand particles in a cold model of fluidized bed incinerator were investigated. The concentration distributions were measured under various experimental conditions such as superficial air velocities, overall compositions of polystyrene beads. On the basis of measured concentration distributions, distributions of local mixing index and global mixing index were calcluated. The mixing index increases as superficial air velocity increases. However, the influence of superficial air velocity on the mixing index is decreased as overall compositions of sand particles is decreased. The further studies will investigate the effect of particles diameters and a quantitative correlation of mixing index with such variables.

전력선 통신(PLC)을 위한 모뎀 개발에 관한 연구

신관우,김용태,이윤섭 공주대학교 생산기술연구소 2001 論文集 Vol.9 No.-

PLC (Power Line Communication) is the communication method using the existing power line installed in houses and offices to convert and transmit high frequency communication signal from tens of KHz to tens of MHz, and receive the filtered signal using high frequency filter. The advantage of PLC is that PLC uses the existing power line installed in houses and offices so it does not require separate power line. Easy and convenient access using electric outlets is another advantage of PLC. However, PLC has some disadvantages such as limited transmission power, high load interference and noise, variable signal attenuation, characteristic of impedance, selective possibility of frequency property. This study designed the boiler temperature control system by unit using the modem designed on the basis of technology used for PLC modem. After conducting experiments with systems, it was possible to control stably. By commercializing this product, we can avoid unnecessary heating of separate temperature control unit, and save the cost accordingly.

경주지역 여고생의 초경과 체성장간의 관계

김준섭,권오구,박진석,오종수,박정현,박제식,안세한,이용환,서정호,신태섭,최영배,김덕수,이관,박수경 東國大學校醫學硏究所 2002 東國醫學 Vol.9 No.1

본 연구는 경주지역 1개 고등학교 3학년 여고생을 대상으로 초경 시작 전인 초등학교 4학년부터 고등학교 2학년까지의 키, 몸무게, 가슴둘레 수치와 초경 연령을 파악하여 여성의 초경이 빠를수록 체성장 속도의 변화가 있을 것이라는 가설을 기초로 두 요인간의 관련성을 파악하고자 시행되었다. 경주시 1개 여자고등학교 3학년생 총 317명에 대해 ㅊ경 나이, 초경시 심리 상태, 초경이 시작되었을 때의 상담 여부와 상담하였던 사람, 부모 신장과 초경전후의 식사 규칙성, 다이어트 경험, 수면시간, 스트레스, 음주/흡연 여부, 질병력 등에 대한 설문 조사를 시행하였고, 초등학교 4학년부터 고등학교 2학년까지의 키, 몸무게, 가슴둘레에 대한 정보는 건강기록부에서 확보하였다. 상기 대상자 중 건강기록부가 분실된 39명, 초경나이에 대해 응답하지 않았던 29명 및 결석 등으로 조사를 하지 못하였던 42명을 제외한 조사 대상자는 206명으로 선정하였다. 대상자들의 초경연령 평균값(Mean±SD)은 13.0±1.11이었고, 초등학교 4학년부터 고등학교 2학년까지의 초경 이후 신장 성장률은 감소하였으며, 초경연령이 빠른 군이 초등학교 때는 신장에 있어서 우위를 차지하나 고등학교에 오면서 신장은 비슷한 수준이 되었다. 초경후 1-2년 사이에 체중과 흉위의 증가율은 감소하였고, 초경연령이 빠른 군이 초등학교와 고등학교 사이에 체중과 흉위에서 모두 우위를 차지하였다. 본 연구의 결과는, 흔히 이차 성징의 시작 시점 혹은 사춘기의 시작 시점으로 보고있는 초경 연령이 청소년기의 성장과 밀접한 관련성이 있고, 특히 체중과 흉위의 성장 속도와 밀접한 관련성이 있음을 시사한다. To understand the onset of menarche in relation to changes in physical growth that take place during female adolescence, especially the changes in height and weight velocity. The 207 senior in one women high school of Kyongju were investigated in April 3 to 8, 2001. We collected the information, relation in the age at menarche, height & weight of parents, regularity of eating, and obesity diet, duration of sleeping, sickness & stress near age at menarche, by self-recording. The status of height, weight & chest circumference between the 4th grade of primary school and the junior of high school was collected by individual Health Record. The results were followed; The average age at menarche was 12.95±1.11 years old and the most frequent age of menarche is 13 years. After menarche, the velocity of height, weight and chest circumference were decreased. The most rapid group of menarche hold dominant position in height during elementary school. As time passed, they dont hold dominant position in height. The most rapid group of menarche get an advantage in the weight and the girth of chest after elementary school. The height of subjects is directly proportional to the height of their parents. These results suggest that the starting age at menestuation can be closely associated with physical growth and development.