Most wastewater treatment plants are facing odor and sludge disposal problems. In this lab-scale study, odor and sludge from wastewater treatment processes were treated using a combined non-thermal plasma and sludge reactor. The hydrogen sulfide concentration introduced to the reactor was varied at 10, 20, and 50 ppm, and its removal efficiency and system performance were determined. Ozone was produced by the plasma reaction at a concentration of 200 ppm under the given condition. 80% of the hydrogen sulfide was removed regardless of its introduced concentration. In addition, due to the ozone carried over to the sludge reactor, the organic constituents in the waste sludge in terms of TCOD decreased by 30%. The ion concentrations of HS- and SO₄²⁻ in the sludge increased during the four hour experimental period. As a result, the plasma oxidation system can treat waste sludge effectively for the simultaneous reduction of sludge volume and odor.

Desorption reaction characteristics of the used activated carbons collected from manufacture of rubber and plastics products in Shiwha/Banwal industrial complex were investigated. Desorption reactions were analyzed based on the data obtained from a thermogravimetric analyzer. Activation energies and reaction orders for desorption reaction characteristics of the used activated carbons were estimated by employing the Friedman method and the Freeman-Carroll method. It was found that the activation energies were 24.7∼41.3 kJ/㏖ in the Friedman method and 13.9∼24.4 kJ/㏖ in the Freeman-carroll method, and reaction orders were 0.3∼1.4.

일반적으로 유화 아스팔트와 폼드 아스팔트를 사용한 현장 상온 재생 아스팔트 포장은 노후한 아스팔트 포장을 재생하는데 가장 경제적이며 친환경적인 재활용 공법이다. 최근, 현장 상온 재생 아스팔트 혼합물의 코팅, 라벨링, 잔류안정도, 양생조건을 향상시켜주는 고점착 유화 아스팔트가 개발되었다. 본 연구의 목적은 현장 상온 재생 아스팔트 포장을 위한 고점착 유화 아스팔트 혼합물과 폼드 아스팔트 혼합물의 실내시험에 대한 반응특성을 비교하는 것이다. 고점착 유화 아스팔트 혼합물은 폼드 아스팔트 혼합물과 비교하여 재활용 골재를 균일하게 코팅시켜주는 것으로 육안 관찰되었다. 현장 상온 재생 아스팔트 포장을 위한 고점착 유화 아스팔트 혼합물과 폼드 아스팔트 혼합물의 마샬안정도와 간접인장강도는 유사한 반응을 보여주었다. 하지만 진공으로 포화된 습윤상태의 고점착 유화 아스팔트 혼합물의 마샬안정도와 간접인장강도는 폼드 아스팔트 혼합물보다 우수한 것으로 나타났다. 4시간 양생 후 고점착 유화 아스팔트 혼합물의 라벨링 현상은 폼드 아스팔트 혼합물보다 적게 발생하였다. 본 실내시험에 대한 반응특성으로부터 현장 상온 재생 아스팔트 포장을 위한 고점착 유화 아스팔트 혼합물은 폼드 아스팔트 혼합물보다 우수한 저항성과 라벨링 저항성을 발휘하는 것으로 평가되었다.

Absorption characteristics of formaldehyde (one of odors) were investigated using a bubble tank. The capacity of reaction tank made of acrylic is I liter and the experiment was carried out as semi-batch mode (for given absorbent packing, formaldehyde was fed continuously with flow rate of 2 liter/min). As operating variables of experiment, concentration of formaldehyde (400~800 ppm), absorption temperature (25~45℃), and packing volume of absorbent (100~300 mL) were used. The experimental results showed that the removal efficiency of formaldehyde decreased from 5 to 10% as the concentration of formaldehyde and the absorption temperature increased from 400 to 800 ppm, and from 5 to 10%, respectively, while it increased with the increase of the packing volume of absorbent.

The combustion reaction of polyvinylchloride(PVC) was investigated using a thermogravimetric technique under an air atmosphere condition at several heating rates from 10 to 50℃/min. To obtain information on the kinetic parameters, the dynamic thermogravimetric analysis curve and its derivative were analyzed by a variety of analytical methods such as Kissinger, Friedman, Chatterjee-Conrad, Ozawa and Coats-Redfern methods. The combustion reaction of PVC proceeded in two steps; the first step was caused by the dehydrochlorination process in PVC, and the second step by the combustion of polyene. The comparative works for the kinetic results obtained from various methods should be performed to determine the kinetic parameters, because there are tremendous differences in the calculated kinetic parameters depending upon the mathematical method taken in the analysis.

Niobium powder was made from potassium heptafluoroniobite () as the raw material using sodium (Na) as a reducing agent based on the hunter process. The apparatus for the experiment was designed and built specifically for the present study. The niobium particle size greatly increased as the reduction temperature increased from to . The particle size was fairly uniform, varying from to depending on the reduction temperatures. The niobium powder morphology and particle size are very sensitive to a reaction temperature in the metallothermic reduction process. The yield of niobium powder increased from 55% to 80% with a increasing a reaction temperature.

본 연구에서는 로봇디자인에 대한 선호 반응의 결과를 바탕으로 로봇 얼굴을 구성하는 조형요소의 조합 관계에 대한 특성을 분석하는 것이 기본적인 목적이다. 아울러 분석 결과로부터 선호도를 향상시키기 위한 디자인가이드의 제시 가능성을 고찰하고자 하였다. 이를 위하여 27가지의 로봇 얼굴 사진을 실험자극으로 선정하고, 선호 반응 및 연상 반응에 관한 실험을 진행하였다. 실험 로봇 얼굴의 형태 보다는 눈의 형태가 선호 반응에 많은 영향을 미치는 등 다양한 특성이 나타났다. 이러한 결과를 바탕으로 로봇 얼굴에 대한 선호반응에 긍정적 영향을 미칠 수 있는 각 조형요소의 특성 도출 및 기본적 디자인가이드라인을 제시할 수 있었다. 구체적으로 먼저, 눈의 형태는 세로의 길이가 가로 길이 보다는 긴(167%) 타원형을 적용하는 것이 필요하다. 그리고 눈 사이의 거리는 얼굴 폭의 35% 정도를 유지해야 한다. 또한 눈의 위치는 얼굴의 중심축으로부터 상향에 배치하여 시각적으로 안정감을 주는 것이 중요하다. 머리 전체의 형태는 원형을 이용한 구 타입이 바람직하다. 머리의 형태와 눈과의 조화는 로봇으로서 기본적으로 갖추어야 할 귀엽고 깜찍한 이미지를 구현하는 것이 필요하다.

The combustion reaction of polypropylene was investigated using a thermogravimetric technique under an air atmosphere condition at several heating rates from 10 to 50℃/min. To obtain information on the kinetic parameters, the dynamic thermogravimetric analysis curve and its derivative were analyzed by a variety of analytical methods such as Kissinger, Friedman, Freeman-Carroll, Chatterjee-Conrad, Ozawa and Coats-Redfern methods. The comparative works for the kinetic results obtained from various methods should be performed to determine the kinetic parameters, because there are tremendous differences in the calculated kinetic parameters depending upon the mathematical method taken in the analysis.

Non-sintering cement was manufactured with briquette ash. Alkali activator for compression bodies used a NaOH solution. In order to apply alkali-activated briquette ash and the non-sintering cement to concrete, several experimental studies were performed. It was necessary to study the binder obtained by means of a substitute for the cement. This study concentrated on strength development according to the concentration of NaOH solution, the curing temperature, and the curing time. The highest compressive strength of compression bodies appeared as 353kgf/cm2 cured at 80˚C for 28 days. This result indicates that a higher curing temperature is needed to get a higher strength body. Also, geopolymerization was examined by SEM and XRD analysis after the curing of compression bodies. According to SEM and XRD, the main reaction product in the alkali activated briquette ash is aluminosilicate crystal.

Absorption characteristics of acetaldehyde (one of odors) were investigated using a bubble tank. The capacity of reaction tank made of acrylic is I liter and the experiment was carried out as semi-batch mode (for given absorbent packing, acetaldehyde was fed continuously with flow rate of 2 L/min). As operating variables of experiment, concentration of acetaldehyde (40~100 ppm), absorption temperature (25~45℃), and packing volume of absorbent (100~300 ㎖) were applied. The experimental results showed that the removal efficiency of acetaldehyde decreased as 20~30%, with increasing concentration of acetaldehyde in the range of 40~100 ppm, and decreased as 15~30%, with increasing absorption temperature in the range of 25~45°C, while it increased with increasing packing volume of absorbent. Reaction rate which is measured by experiment is well matched with the calculated one from theoritical rate equation.