• 항공우주시스템공학회지
• /
• 제9권2호
• /
• pp.34-40
• /
• 2015

Staged combustion cycle engines are well known to have high combustion efficiencies and specific impulse. In this study, design of mixing head part of combustion chamber for 8tonf class staged combustion cycle rocket engine (ES-08) was performed. Structural stability of the mixing head part of the combustion chamber is very important design factor because it is loaded by high temperature and high pressure of fuel and oxidizer as well as by thrust load simultaneously. Uniformity of flow distributions of the propellants to the injectors is also important factor. First, a basic configuration for the ES-08 mixing head part was designed on the basis of the structural design requirements. And then, the structural analyses were performed on the basic configuration as well as some of reinforced configurations. As the structural analyses results, the most stable configuration was selected for the ES-08 mixing head part. In order to examine the uniformity of the flow distributions of the propellants through the manifold of the mixing head, flow analysis was performed based on the selected configuration. The results of the flow analysis showed that the fuel and the oxidizer were uniformly supplied to the injector.

• 한국기계가공학회지
• /
• 제16권5호
• /
• pp.157-165
• /
• 2017

The high-pressure resin transfer molding (HP-RTM) technology has been commercialized for fast production of fiber reinforced composite materials. The high-pressure mixing head was one of the most core component of the HP-RTM process. In this study, a mixing head was systematically designed, manufactured and evaluated. This mixing head was composed of a nozzle, a mixing chamber, a cleaning piston part, and an internal mold release part. In actual, a straight-type structure was newly designed instead of the conventional L-type structure for improving the maximum mixing pressure and mixing ratio precision. The performance of mixing head was showed maximum mixing pressure of 15.22MPa and mixing ratio precision of 0.12%. CFRP molding experiments were successfully obtained a 6~11 laminating carbon sheet using HP-RTM presses and specimen molds.

• 한국추진공학회지
• /
• 제26권3호
• /
• pp.54-65
• /
• 2022

2단형 소형위성발사체 상단 메탄엔진에 다중점화가 가능한 간결한 점화기를 개발하고 있다. 첫 번째로 적층제조 기술을 활용하여 믹싱헤드와 일체형으로 다중점화장치를 설계 및 제작하였다. 두 번째로 연소기 헤드에 공급되는 점화 추진제를 주-추진제 배관에서 분기하여 공급함으로써 점화가스 저장을 위한 별도의 고압 용기가 필요없다. 1톤급 액체산소/액체메탄 엔진 연소기 헤드에 일체형으로 고안된 신규 점화기에 대해서 점화기 단독시험, 연소기 점화시험 및 연소기 성능시험 등의 다양한 시험을 수행하였고, 안정적인 점화 성능을 확인하였다.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2009년도 제33회 추계학술대회논문집
• /
• pp.608-612
• /
• 2009

30톤급 액체로켓엔진 연소기 개발 기술을 바탕으로 75톤급 기술검증용 연소기 시제품을 제작하였다. 시제품 제작에서 검증하고자 하였던 일부 기계가공 공정 및 접합 기술들은 75톤급 연소기에서도 동일하게 적용할 수 있음을 확인하였다. 새롭게 설계된 연소기 헤드부는 새로운 공정을 적용하여 제작하였다. 기술검증용 시제품을 통해 확립된 공정 및 기술들은 대형 액체로켓엔진 연소기 제작 기술의 신뢰성을 향상 시킬 것이다.

• Journal of Biosystems Engineering
• /
• 제35권2호
• /
• pp.91-99
• /
• 2010

A Model of small scale total mixed rations(TMR) plant which can be utilized round bales was developed, tested and analyzed in this study. This study consist of two parts. One is development of a small scale TMR plant model which was already reported at the previous paper. This is the second part of the study. For the study, a series of tests of the model plant were performed and its costs was analyzed. Also, the break-even point of the model plant by comparing with market price of commercial TMR feed was determined. Results of the research are summarized as follows ; As the results of mixing test, the average coefficient of variation(CV) value for mixing of the feed was 13.0 % at the gate of the mixer. The production cost was estimated as 8,298 won/head for dairy cattle farm and 2,495 won/head for beef cattle farm, when producing 8 batch a day. Also, it is recommended to utilize the model plant when farm size is over 79 heads for dairy cattle farm and 113 heads for beef cattle farm. As an overall conclusion, the model plant designed for farm size TMR feed mill will be very useful model for both beef cattle and dairy farms in Korea. Also it is expected that the capital investment for the model plant can be recovered with 8 months compare with purchasing commercial TMR feed if the model plant feeds 1,000 beef cattle approximately.

• 복식문화연구
• /
• 제13권4호
• /
• pp.622-631
• /
• 2005

The purpose of this study is to know variety winding ways for scarf and to know the trends of scarf expression methods with seeing how to affect these ways on recent fashion. Investigating for scarf's concept and feature through theory records and looking for variety scarf expression ways were done for this study. And then The photo data of fashion magazines from s/s 2000 to s/s 2005, focusing on the divided scarf expressions, were analyzed. The frequencies of scarf expression are like this; decorating on the neck($60\%$), decoration on the shoulders($18\%$), decorating on the head($10\%$), etc($9\%$), using for accessaries($3\%$). Decorating on the necks is shown lasting ways. Also recently the methods breaking the established concepts - the mixing with two ways and the pratical using scarf' as a part of clothes - have a tendency to increase steady.

• 한국정밀공학회지
• /
• 제31권8호
• /
• pp.659-663
• /
• 2014

Manufacturing processes of industrial tire are composed of mixing, extrusion, curing, trimming and inspecting. Among them curing is the most important process in the production of industrial tire. In this study the newly developed spring vent system was designed in order to solve rubber intrusion problem inside spring vent system in the curing process. After the experiment it is concluded that rubber intrusion was caused by angled stem head part. New spring vent system was manufactured and new design of spring vent system is proper to use for industrial tire curing process.

• 보존과학회지
• /
• 제18권
• /
• pp.63-74
• /
• 2006

경주서악리 삼층석탑의 모든 부재는 정동이 잘 발달된 중립질의 회백색 알카리 화강암으로 구성되어 있다. 이 석탑은 이미 보수되어 전체적으로 안정감을 주며 상륜부를 제외하면 거의 원형을 보존하고 있다. 그러나 석탑에 직접적인 영향을 가하는 주변의 수목과 지반에 서식하는 잔디의 영향으로 지대석과 기단부 및 옥개석의 상부에는 지의류를 비롯한 미생물의 서식이 심각한 상태이다. 따라서 보존처리는 일차 건식세정을 실시하였고 이차로 습식세정을 실시하였다. 이때 잘 제거되지 않는 지의류 및 오염물 등은 고온스팀을 이용하여 제거하였다. 또한 이미 보수에 사용되었던 콘크리트와 에폭시 수지를 제거를 하고 에폭시계 합성수지에 탈크와 알카리 화강암 파우더 등의 충전제를 혼합하여 복원하였다. 부재들의 질감을 맞추기 위해 합성수지와 충전제의 혼합과정에서 색 맞춤을 하였다. 또한 석탑의 동쪽에 있는 사면으로부터 흘러내리는 빗물의 유입을 최소화하기 위해 배수로를 설치하였으며, 석탑주변에 서식하고 있는 수목 및 잔디를 제거하여 습기 발생을 최소화함으로서 향후지의류의 발생을 억제시키고자 하였다.

• 한국의류학회지
• /
• 제40권4호
• /
• pp.746-762
• /
• 2016

This study considers expression techniques and aesthetic values in the images of head dress reflected in a natural motif. The conclusions of the study are as follows. The first type is the realistic expression (52.4%) such as the reproduction of a natural object's essential form (27.0%), the partial derivation of the natural object (19.3%), and the planarization for the actual image of the natural object (6.1%). The second type is a metaphorical expression (39.0%) which emphasizes the morphological characteristics of nature (18.2%), the structuration of the natural object's silhouette into a three-dimensional or two-dimensional form (11.5%), and the abstract expression of the form in the natural object (9.3%). The third type is a hybrid expression (8.6%) that is a compromise between practical (or metaphorical expressions) so that expression techniques represent a compromise between the natural object's essential form and abstract expression (4.6%) or the combination of the natural object's silhouette into a three-dimensional or a two-dimensional visualization (4.0%). Aesthetic head dress values reflected in the natural motif first indicate a primitive value. This state of natural instinct recreates the natural object or combines part of the biological elements of the natural object to create an inducement to escape from the practical world. The second is amusement in the expression of animals in dynamic and humorous forms creates an illusion of animals being alive with a representative playful enjoyment. The third is abstraction that grant freedom in the observer's aesthetic rational through a reinterpretation of the fashion designer. The fourth is eclecticism where a compromise represents an act of mixing a variety of independent factors to create harmony with the imagery of nature created through the grafting of diverse expression techniques that break away from stereotypes of existing natural objects to create a type of nature that cultivates new values.

• Ocean and Polar Research
• /
• 제25권4호
• /
• pp.447-457
• /
• 2003

In order to understand the distribution of changes of geochemical characteristics in surface sediments according to various environmental changes around the artificial Lake Shihwa, surface sediments were sampled at $13{\sim}15$ sites form 1997 to 1999 and analyzed by C/S analyzer, ICP/MS and AAS. The average $S/C_{org}$ ratio was 0.35 in the surface sediments, which is similar to 0.36, the characteristic ratio of marine sediments. Heavy metal contents and enrichment factors in the surface sediments tended to be decreasing from the head to the mouth of the Lake Shihwa. With the deposition of fine-grained sediments in the central part of lake, anoxic water column induced the sulfides compounds with Cu, Cd and Zn. Metals such as Al, Fe, Cr, Co, Ni, Cu, Zn and Cd except for Mn and Pb showed relatively high correlation coefficients among them. The contents of Cr, Co, Ni, Cu, Zn and Cd in the surface sediments of the lake were two to five times higher than those in the lake before dike construction and also in outer part of the dike. These are mainly due to the Input of untreated industrial and municipal waste-waters into the lake, and the accumulation of heavy metals by limitation of physical mixing. Although metal contents of the surface sediments at the sites near the water-gate due to outer seawater inflow tended to be lower than those during the desalination, heavy metals were deposited in areas around the new industrial complex in the evidence of spatial distribution of heavy metals in the sediments. This is mainly due to the input of untreated waste-waters from tributaries.