특집02 : 스마트 자동차 ; 스마트 자동차 능동적 안전 확보 동향

구태완,주백수,이승곤,금득규 한국정보처리학회 2015 정보처리학회지 Vol.22 No.3

권총의 반동력 측정 시스템의 실험적 연구

구태완,강범수,박문선 한국항공우주학회 1998 한국항공우주학회 학술발표회 논문집 Vol.- No.-

A study on process parameters for cold U-bending of SUS304L heat transfer tube using rotary draw bending

구태완,Jin-Hyun Cha,Yu-Beom Kim,Ok-Gyu Kwak,Won-Seok Kim,강범수 대한기계학회 2013 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.27 No.10

Steam generator is one of enormous heat exchangers that use heat energy derived from a reactor of nuclear power plant for generating steam. The steam obtained is drained into a turbine, and plays an important role for power generation. The heat transfer tubes of each steam generator used in a pressurized water reactor (PWR) are composed of about 8,000 ~ 13,000 U-shaped tubes. These tubes act as the structural material and the thermal boundary. Furthermore, these tubes account for about 70% of the cooling surface area, transmitting thermal energy between the high-temperature (about 320°C), high-pressure (about 157 Kgf/cm2) primary coolant derived from the reactor and the secondary coolant, which is at about 220°C and 60 Kgf/cm2, from the secondary system. These heat transfer tubes used in the steam generator within the PWR were fabricated from seamless tubes of stainless steel (SUS304L), Alloy 600 and Alloy690. In this study, numerical and experimental investigations are carried out on the U-bending process for fabricating heat transfer tubes from long straight SUS304L tubes. In the numerical simulation, 3-dimensional finite element analysis is performed using ABAQUS Explicit/Implicit. In detail, process parameters such as the angular speed, U-bending period, and bending angle taking into account elastic recovery after cold U-bending are considered. Additionally, experimental investigations are conducted to verify the suitability of the predicted U-shaped geometries in terms of the ovality and wall thickness of the U-shaped heat transfer tubes.

다양한 실규모 혐기소화조에서 유래된 프로피온산 분해 미생물 군집 구조 해석 및 생장역학 연구

구태완,이장우,Abu jannat⋅,황석환 한국폐기물자원순환학회 2016 한국폐기물자원순환학회 학술대회 Vol.2016 No.11

Anaerobic digestion is one of the most economical ways to treat organic wastes; the production of excessive sludge is limited; aeration is not required; operation cost is low; valuable energy resource (methane) is produced. However, propionate, an intermediate substance during the process, is known to inhibit biochemical process at high concentration; but it is difficult to be degraded biologically as its oxidation is thermodynamically unfavorable (△G>0). However, there are several microorganisms which could oxidize propionate fully by their syntrophic association. Therefore, in this research, the propionate enrichment culture was produced in large amount (~1L), and the main players which are responsible for utilizing propionate are identified. Furthermore, the kinetic parameter was obtained from this research. Seed came from two different full-scale anaerobic digesters which is located in Joongrang (JR) and Sincheon (SC). 16s rRNA gnee based metagenomics results indicated that Smithella propionica and Methanobacterium beijingense were the most dominant species in all seeds. The fact that bacterial family Syntrophomonadaceae and archaeal genus Methanosaeta were also found significantly in all seeds means that there might be symbiotic relationship among propionate oxidizing bacteria, butyrate oxidizing bacteria, hydrogenotrophic methanogens and acetotrophic methanogens in complete oxidation of propionate. Based on the first order kinetic which indicated propionate degrading rate, k (1/day) on JR and SC was represented 0.0243 and 0.0223, respectively. Also, based on Modified-Gompertz model, umax on JR and SC was represented as 0.024 and 0.016, respectively.

돈분뇨를 기질로 활용한 고부가 가치 상황버섯 균사체 배양조건 최적화 연구

구태완,이준엽,조경진,이장우,신승구,황석환 유기성자원학회 2015 유기물자원화 Vol.23 No.2

Newly, nutrients recovery by bioconversion in the swine waste which caused serious problems due to its high organic fraction and content of nutrients such as phosphorus and nitrogen is viewed as a considerable approach since it produces valuable product as well as recycling of resources. Consequently, it is necessary to find new methods to treat swine waste. One possible solution to this problem is to use this potential pollutant as a growth substrate for economically valuable products. The study for the fundamental improvement of bioconversion efficiency by finding optimum growth conditions using statistical models and biotechnology was performed. A novel approach to utilize swine waste by cultivating mycelia of the mushroom Phellinus linteus are described. A central composite face-centered design (CCF) for the experiments was used to develop empirical model providing a quantitative interpretation of the relationships among the three variables, which were substrate concentration, pH, and temperature. The maximal radial extension rate (2.78mm/d) of P.linteus was determined under the condition of 5.0 g COD/L, pH 5.0, and temperature 29.7℃. The results of this study suggest that swine waste could be utilized as a growth substrate for the cultivation of mushroom mycelia enhancing an efficiency of utilizing this by-product of the livestock industry.

농축산분야 미세먼지 활동도 자료 개선 연구

구태완,문수호,최두선 한국대기환경학회 2021 한국대기환경학회 학술대회논문집 Vol.2021 No.10

농업활동을 통해 1차적으로 발생할 수 있는 미세먼지로는 비산먼지가 있으며 주로 봄철 경운시기와 가을철 수확시기 및 농촌에서 농업잔재물을 소각하는 행위로 인한 미세먼지가 발생하고 있다. 더불어, 축산활동은 축사에서 발생하는 가축 사육두수에 의해 기인한다. 국내 2017년 기준 농업과 축산과 관련된 배출원(비산먼지) 중 미세먼지 배출량은 PM-10 20,533톤/년, PM-2.5 3,932톤/년이며 농업활동과 축산활동의 배출비율은 거의 50:50으로 나타났다. 현재 농업활동에 의한 미세먼지 배출계수와 활동도 자료는 미국 CARB (2007)를, 축산활동은 유럽 EEA(2006)를 그대로 적용하고 있듯이 아직까지 인벤토리와 활동도 자료가 개선되지 않았다. 따라서 본 연구는 국내 농업 및 축산활동 변화가 따라 기존 농업 및 축산활동 분야 활동자료인 시간적, 공간적 해상도의 개선안을 제시하고자 한다.

소형부품의 사각 컵 드로잉 성형 해석에 관한 실험적 연구

구태완,강범수 한국소성가공학회 2001 소성가공 : 한국소성가공학회지 Vol.10 No.6

Milli-structure components are classified as a component group whose size is between macro and micro scales, that is, about smaller than 20mm and larger than 1mm. The forming of these components has a typical phenomenon of bulk deformation with thin sheets because of the forming size. In this study, milli-structure rectangular cup drawing is analyzed and measured using the finite element method and experiments. Special containers or cases of cellular phone vibrator to save installation space are produced by rectangular-shaped drawing. A systematic approach is established for the design and the experiment of the forming processes for rectangular milli-structure cases. To verify the simulation results, the experimental investigations were also carried out on a real industrial product. The numerical analysis by FEM shows good agreement with the experimental results in view of the deformation shape of the product.

펜톤산화 공정에서 발생하는 슬러지의 재활용 방안 연구

구태완,조순행,최영수 대한환경공학회 1998 대한환경공학회 학술발표논문집 Vol.1998 No.12

입자요소를 이용한 미세 성형 부품의 유한요소 해석 및 실험

구태완,강범수,Ku, Tae-Wan,Kang, Beom-Soo 대한기계학회 2003 大韓機械學會論文集A Vol.27 No.1

The recent trend towards miniaturization causes an increased demand for parts with very small dimensions. Milli-structure components are classified as a component group whose size is between macro- and micro-scale. The manufacturing process of these components of thin sheet metal forming has a microscopic properties in addition to a typical phenomenon of bulk deformation because of the forming size. Also, the material properties and the deformation behavior change with miniaturization, which means that, a coarse grained materials show a higher resistance against deformation, when the grain size is in the range of the sheet thickness. In this study, a new numerical approach is proposed to simulate intergranular milli-structure in forming by the finite element method. The grain element and grain boundary element are introduced to simulate the milli-structure in the bending. The grain element is used to analyze the deformation of individual grain while the grain boundary element is for the investigation on the movement of the grain boundary. Also, the result of the finite element analysis is confirmed by a series of milli-sized forming experiments.

Numerical and experimental approach on energy dissipation in nano colloidal damper

구태완,S. B. Jeon,V. H. Bui,송우진,M. S. Park,강범수 대한기계학회 2007 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.21 No.10

Mechanical damping systems have been widely used to various mechanical structures and systems, and are mainly hydraulic and pneumatic devices nowadays. New damping system such as nano colloidal damper (NCD) is complementary to the hydraulic one, having a cylinder-piston-orifice structure. This study includes numerical and experimental investigation about energy dissipation of NCD by using porous silica particles. In numerical approach, the dissipated energy was obtained between compression and relaxation processes for porous silica particle in NCD according to the capillary tube theory. Furthermore, for colloidal damper, the hydraulic oil was replaced by a colloidal suspension that was consisted of a nano-porous matrix with controlled architecture and a lyophobic fluid. NCD test rig and the measuring technique of the hysteresis were described in this study. Performance of the energy dissipation between numerical and experimental results was investigated and compared. As a result, the proposed NCD was proved to efficiently dissipate the mechanical energy.