The object of this study is to feasibility assesment for co-digestion efficiency of food waste recycling wastewater(FWR) with thermal hydrolysis process dehydration cake (THP Sludge). As a result of THP pre-treatment experimental conditions to 160oC and 30 minutes, the solubility rate(conversion rate of TCOD to SCOD) of the THP sludge increased by 34%. And the bio-methane potential in the THP sludge increased by about 1.42 times from 0.230 to 0.328 m3 CH4/kg VS compared to the non-pre-treatment. The substrates of the co-digestion reactor were FWR and THP sludge at a 1:1 ratio. Whereas, only FWR was used as a substrate in the digestion reactor as a control group. The experimental conditions are 28.5 days of hydraulic retention time(HRT) and 3.5 kg VS/m3-day of organic loading rate(OLR). During the 120 days operation period, the co-digestion reactor was able to operate stably in terms of water quality and methane production, but the FWR digestion reactor deteriorated after 90 days, and methane production decreased to 0.233 m3 CH4/kg VS, which is 67% of normal condition. After 120 days of the experiment, organic loading rate(OLR) of co-digestion reactor was gradually increased to 4.5 kg VS/m3-day and operated for 80 days. Methane production during 80 days was evaluated to be good at the level of 0.349 m3 CH4/kg VS. As a result of evaluating the dehydration efficiency of the sludge before/after 150-180oC THP using a filter press, it was confirmed that the moisture content of the sludge treated before THP at 180oC was 75% and improved by 8% from 83-85% level. Therefore, it is expected that the co-digestion reactor of FWR and THP sludge will ensure stable treatment water quality and increase bio-methane production and reduction effect of dehydration sludge volume.

Despite numerous advances in the preparation and use of GaN, and many leading-edge applications in lighting technologies, the preparation of high-quality GaN powder remains a challenge. Ammonolytic preparations of polycrystalline GaN have been studied using various precursors, but all were time-consuming and required high temperatures. In this study, an efficient and low-temperature method to synthesize high-purity hexagonal GaN powder is developed using sub-micron Ga2O3 powder as a starting material. The sub-micron Ga2O3 powder was prepared by an ultrasonic spray pyrolysis process. The GaN powder is synthesized from the sub-micron Ga2O3 powder through a nitridation treatment in an NH3 flow at 800℃. The characteristics of the synthesized powder are systematically examined by X-ray diffraction, scanning and transmission electron microscopy, and UV-vis spectrophotometer.

Two sewage treatment facilities were selected to identify odor emission characteristics, focusing on volatile organic compounds (VOCs) and sulfur compounds. The complex odor, 5 kinds of sulfur compounds and 23 kinds of VOCs were analyzed from gas and sludge storages. Hydrogen sulfide was detected in the highest concentration and had the highest odor quotient among the odorous compounds monitored in this study, demonstrating that the contribution of hydrogen sulfide to the complex odor reached up to 90%. For VOCs, the overall contribution to the complex odor was not critical but VOCs can sufficiently trigger an odorous sensation because the sum of the odor quotient reached up to 2.89.

Hydrogen is considered a potential future energy source. Among other applications of hydrogen, hydrogen-rich water is emerging as a new health care product in industrial areas. Water electrolysis is typically used to generate a hydrogen rich water system. We annealed 10AA carbon paper in air to use it as an electrode of a hydrogen rich water generator. Driven by annealing, structural changes of the carbon paper were identified by secondary electron microscope analysis. Depending on the various annealing temperatures, changes of the hydrophilic characteristics were demonstrated. The crystal structures of pristine and heat-treated carbon paper were characterized by X-ray diffraction. Improvement of the efficiency of the electrochemical oxygen evolution reaction was measured via linear voltammetry. The optimized annealing temperature of 10AA carbon paper showed the possibility of using this material as an effective hydrogen rich water generator.

Response surface methodology (RSM) based on a Box-Behnken Design (BBD) was applied to optimize the thermal-alkaline pre-treatment operating conditions for anaerobic digestion of flotation scum in food waste leachate. Three independent variables such as thermal temperature, NaOH concentration and reaction time were evaluated. The maximum methane production of 369.2 mL CH4/g VS was estimated under the optimum conditions at 62.0°C, 10.1% NaOH and 35.4 min reaction time. A confirmation test of the predicted optimum conditions verified the validity of the BBD with RSM. The analysis of variance indicated that methane production was more sensitive to both NaOH concentration and thermal temperature than reaction time. Thermal-alkaline pretreatment enhanced the improvement of 40% in methane production compared to the control experiment due to the effective hydrolysis and/or solubilization of organic matters. The fractions with molecular weight cut-off of scum in food waste leachate were conducted before and after pre-treatment to estimate the behaviors of organic matters. The experiment results found that thermal-alkaline pre-treatment could reduce the organic matters more than 10kD with increase the organic matters less than 1kD.

Numerous experiments have demonstrated that infrared thermographic methods are effective for detection of subsurface defects in the materials. The response of the material to the thermal stimulus is dependent on the existence of subsurface defects and their features. In order to obtain the information about defects, the material’s response to the thermal stimulus is studied. In this study, image processing was applied to infrared thermography images to detect defects in metals that were widely used in industrial fields. When analyzing experimental data from infrared thermographic testing, thermal images were often not appropriate. Thus, four point method was used for processing of every pixel of thermal images using MATLAB program for quantitative evaluation of defect detection and characterization which increased the infrared non-destructive testing capabilities since subtle defects signature became apparent..

저곡해충 중 대표적인 거짓쌀도둑거저리(Tribolium castaneum), 어리쌀바구미 (Sitophilus zeamais), 화랑곡나방(Plodia interpunctella), 이질바퀴(Periplaneta americana)에 대한 열처리 방제시스템에 훈증제(Phosphine), CO2, 식용규조토를 복합처리하여 식품가공공장, 사일로, 컨테이너 등에 대한 현장적용시스템을 개발 하였다. 식품가공공장의 해충 주요 서식처는 공장설비 내부 혹은 바닦면의 작은 틈새로 써 대기 온도뿐만 아니라 생산설비와 건물 표면의 온도가 최소 50℃이상 열평형을 이루기 위해서는 약 24시간 이상의 온도 관리가 필요하였다. 또한 현장에서 열처리 시 살충효과 개선 및 방제시간 단축, 그리고 방제온도 감소를 위해서 4종 해충을 4 0℃ 및 45℃ 조건에서 Phosphine 50ppm, CO2 2%, 규조토 0.5g/m3 복합처리하여 사멸율(LT100)을 조사하였으며, 거짓쌀도둑거저리의 경우 약 36시간(45℃ 단독 처리)에서 9시간(45℃ + Phosphine + CO2 + 규조토 복합처리)으로 방제시간이 급 격히 단축되었다. 열처리와 함께 복합처리된 Phosphine과 CO2의 경우 가스형태로 공장 밀폐도가 부족하여 1일 약 10∼20%정도의 농도가 감소하였다. 저장곡물 보 관용으로 주로 사용되는 사일로는 일반적으로 직경 약 2m이상이고 높이 약 10∼ 25m정도의 원기둥 형태로써, 해충의 주요 서식처는 상부 여과장치 부분이다. 이 경 우 열방제 장비를 사일로 하단 내부에 두고 열풍의 토출부를 사일로 상부에 위치하 여 방제를 수행할 경우 효과적이였다. 또한 수출입 콘테이너의 경우 식품가공공장 과 달리 구조물의 밀폐도가 우수하였으며, 이 경우 Phosphine 및 CO2와 같은 가스 의 적용이 효과적인 것으로 확인되었다.

화랑곡나방(Plodia interpunctella)은 전 세계적으로 분포하고 있는 저장, 가공 농산물의 해충으로서 심각한 피해를 끼치고 있으며, 기존의 열처리 방법은 50-60℃의 조건에서 48시간 이상 고온처리가 요구된다. 그러나 이 조건은 비용 및 시간이 많이 들므로 개선할 필요가 있다. 본 연구에서는 열처리의 효율을 높이기 위하여 규조토를 복합처리 함으로 기존의 열처리 조건보다 훨씬 더 효과적이고 경제적인 방법을 개발하고자 하였다. 화랑곡나방의 발육단계 중 열 저항성이 가장 큰 방황기 유충을 대상으로 상온(25℃)과 40℃의 조건으로 규조토를 혼용처리 하였다. 실험 결과 방황기 유충은 25℃에서 24시간 후 살충률이 0%, 40℃에서는 28.3%였다. 방황기 유충에 4 ㎎/L의 규조토를 처리하였을 경우, 25℃에서 0%와 40℃에서 100%의 살충률을 관찰하였다. 즉, 규조토와 함께 열처리를 할 경우 살충 효능이 증가했다. 이 효과는 스트레스 유전자 shsp, hsp70, hsp90 발현 패턴에서도 살충률 실험결과와 같은 패턴으로 관찰 된다. 본 연구를 통하여 열처리 시 규조토를 혼용함으로써 기존의 열처리 조건보다 낮은 온도에서 저장 곡물 해충의 방제효과를 증가시킬 수 있을 것으로 판단된다.

소비자의 먹거리에 대한 의식수준이 최근 지속적으로 높아짐에 따라서 무독성, 비잔류성의 친환경 해충방제시스템의 개발이 시급한 실정이다. 저장곡물의 해충 방제로는 주로 훈증제를 많이 사용하지만 안정성, 환경파괴, 잔류농약, 중복사용으 로 인한 해충의 내성문제 등이 발생되고 있다. 따라서 최근 소비자에게 보다 안전하 고 환경 친화적인 저장곡물 해충방제 열처리시스템이 개발되어 국내 제분회사 등 에 사용되고 있다. 열처리시스템은 실내 온도를 50℃이상 일정시간(약 24∼48hr) 유지하여 해충, 세균, 설치류 등 유해 생물을 방제하는 것으로 이미 선진국에서는 널리 활용되는 친환경적 차세대 해충방제법이다. 본 연구소는 저곡해충 중 대표적 인 거짓쌀도둑거저리(Tribolium castaneum), 어리쌀바구미(Sitophilus zeamais), 화랑곡나방(Plodia interpunctella), 이질바퀴(Periplaneta americana)를 사용하여 열처리시스템에 훈증(Phosphine), 대기조성(CO2), 규조토를 복합처리하여 방제 시간을 단축하거나 방제 온도를 낮추고자 연구를 진행하였다. 4종 해충 각각에 대해서 상온(25℃) 및 45℃ 조건으로 Phosphine, CO2, 규조토를 각각 처리한 경우 처리농도가 높아짐에 따라서 사멸시간이 단축됨을 확인하였다. 이 경우 상대적 Phosphine과 규조토의 해충 사멸 상승효과가 CO2보다 큰 것으로 나타났다. 또한 거짓쌀도둑거저리에 대해서 열(40, 45℃), Phosphine(20, 50ppm), CO2(2, 5, 10%), 규조토(0.2, 0.5, 1mg/L)를 각각 복합처리시 40℃조건에서는 사멸 시간이 72시간(40℃ 단독처리)에서 3~6시간(40℃+Phosphine+CO2+규조토 복합 처리)으로, 45℃조건에서는 24시간(45℃ 단독처리)에서 1~3시간(45℃+Phosphine +CO2+규조토 복합처리)으로 단축되었다.

The purpose of this study is to investigate the crystalline structure and optical properties of (GaZn)(NO) powders prepared by solid-state reaction between GaOOH and ZnO mixture under NH3 gas flow. While ammoniation of the GaOOH and ZnO mixture successfully produces the single phase of (GaZn)(NO) solid solution within a GaOOH rich composition of under 50 mol% of ZnO content, this process also produces a powder with coexisting (GaZn)(NO) and ZnO in a ZnO rich composition over 50 mol%. The GaOOH in the starting material was phase-transformed to α-, β-Ga2O3 in the NH3 environment; it was then reacted with ZnO to produce ZnGa2O4. Finally, the exchange reaction between nitrogen and oxygen atoms at the ZnGa2O4 powder surface forms a (GaZn)(NO) solid solution. Photoluminescence spectra from the (GaZn)(NO) solid solution consisted of oxygen-related red-emission bands and yellow-, green- and blue-emission bands from the Zn acceptor energy levels in the energy bandgap of the (GaZn)(NO) solid solutions.

The establishment of optimal producing condition for rice-based infant foods using modified rice powder was attempted. The modification of rice powder was prepared by microwave heating as well as partial enzymatic hydrolysis. Not only thermal treatment but also enzymatic hydrolysis on rice powder increased D.E. value from 1.25 to 3.81. The water binding capacity, swelling power, solubility, digestibility by α-amylase, light transparency, and paste clarity of the modified rice powder compared to unmodified rice powder were increased from 107% to 249%, from 7.80 to 42.52, from 0.04% to 0.89ft, from 9.19% to 23.01, from 33% to 42%, and from 2.2% to 3.9%, respectively. On the other hand, gelatinization temperature, apparent viscosity, and degree of retrogradation of modified rice powder showed negative correlation with D.E. value. The 「results suggested that the thermal and enzymatic treatment on rice powder improved the physicochemical properties of rice based infant food by enhancing carbohydrate absorptionability and lowering the viscosity and opacity.

다이아몬드 증착시 기판의 표면처리를 변화시켰을 때 다이아몬드의 핵생성 밀도에 미치는 영향에 대하여 연구하였다. 실험장치는 열 필라멘트 CVD 장치를 사용하였고, 반응가스로 메탄과 수소가스를 사용하였다. 기판의 표면 처리는 탄소 상을 기판에 증착시키는 방법, Soot에 의한 기판 표면처리, 혹연에 의한 기판 표면처리로 크게 3가지로 행하였다. 모든 경우에 핵생성 밀도가 증가하였으나 탄소 상을 증착시킨 경우와 soot에 의한 사전처리의 경우의 핵생성 밀도의 증가가 혹연에 의한 처리보다 더 현저하였다. 또한 탄소강의 증착의 경우 표면에 굴곡이 없는 매우 평탄하고 균일한 다이아몬드 막을 얻을 수 있었다. 사전증착처리 한 기판에 탄소 층을 형성시켰을 때 탄소 층과 기판과의 접착력이 약한 것을 이용하여 다이아몬드 막을 쉽게 분리시켜 free standing 다이아몬드 박막을 얻을 수 있음을 알았다.