• 대한조선학회논문집
• /
• 제51권4호
• /
• pp.291-299
• /
• 2014

In the design process of ship or its comprising components, the key to the successful design is how to guarantee the structural safety satisfying the international standard and regulation, which sometimes is not clear enough to cover the detail designs. This study deals with the design procedure for submersible viewing window installed in catamaran. As the window material, the Plexiglass, a type of reinforced plastic, is considered to satisfy the design requirements of international standard. Window thickness is calculated using geometric nonlinear finite element analysis, in order to take into account possible large deformation due to low stiffness of the Plexiglass, and the results are compared with those determined by the procedure specified in ISO12216. Finally, for the validation of proposed design, the pressure test had been carried out following the procedure specified in the standard, and structural safety was checked.

• 대한방사선기술학회지:방사선기술과학
• /
• 제38권1호
• /
• pp.17-21
• /
• 2015

소아백혈병의 치료방법 인 조혈모세포이식법의 전처치 방법으로서 항암제와 함께 대표적으로 사용되고 있는 전신방사선조사에 대하여 치료를 시행하기 전 정량적인 인체장기에 대한 선량을 평가하고자 하였다. 모의실험 프로그램 MCNPX를 사용하여 가상의 공간에서 소아용 모의피폭체를 대상으로 조직보상체의 재질을 변화시켜 실험을 진행하였다. 그 결과 첫째, 평균피부선량은 조직보상체의 재질에 따라 Plexiglass는 74.60 mGy/min, Al은 73.96 mGy/min, Cu는 72.26 mGy/min, Pb의 경우 67.90 mGy/min을 보였다. 둘째, 심부선량은 조직보상체 재질에 상관없이 갑상선, 생식선, 소화기계, 머리, 폐, 신장의 순으로 높게 나타났다. 끝으로 조직보상체와 환자와의 거리는 50 cm 이격시켰을 때가 이상적인 것으로 분석되었다. 본 연구결과를 토대로 할 때, 조직보상체 Al, Cu, Pb은 현재 사용되고 있는 Plexiglass 재질을 대체할 수 있을 것으로 판단된다.

• 대한방사선기술학회지:방사선기술과학
• /
• 제41권2호
• /
• pp.141-148
• /
• 2018

This study examined the properties of photons and the dose distribution in a human body via a simulation where the total body irradiation(TBI) is performed on a pediatric anthropomorphic phantom and a child size water phantom. Based on this, we tried to find the optimal photon beam energy and material for beam spoiler. In this study, MCNPX (Ver. 2.5.0), a simulation program based on the Monte Carlo method, was used for the photon beam analysis and TBI simulation. Several different beam spoiler materials (plexiglass, copper, lead, aluminium) were used, and three different electron beam energies were used in the simulated accelerator to produce photon beams (6, 10, and 15 MeV). Moreover, both a water phantom for calculating the depth-dependent dosage and a pediatric anthropomorphic phantom for calculating the organ dosage were used. The homogeneity of photon beam was examined in different depths for the water phantom, which shows the 20%-40% difference for each material. Next, the org an doses on pediatric anthropomorphic phantom were examined, and the results showed that the average dose for each part of the body was skin 17.7 Gy, sexual gland 15.2 Gy, digestion 13.8 Gy, liver 11.8 Gy, kidney 9.2 Gy, lungs 6.2 Gy, and brain 4.6 Gy. Moreover, as for the organ doses according to materials, the highest dose was observed in lead while the lowest was observed in plexiglass. Plexiglass in current use is considered the most suitable material, and a 6 or 10 MV photon energy plan tailored to the patient condition is considered more suitable than a higher energy plan.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 1993년도 제1회 학술강연회논문집
• /
• pp.55-61
• /
• 1993

An experimental investigation was conducted in order to determine the flammability limit of the solid fuel ramjet using the backward facing step flow combustion of the plexiglass grain. In order to get the different step height ratio, the grain was drilled straight forward or stepwise. The Phoenics computer code was adopted in order to compare. the flow patterns of the some sample tests using a non-reacting cold turbulent flow model. The stepwise grain give some loading advantage; specially thin and long shape grain design.

• 한국해양공학회지
• /
• 제8권1호
• /
• pp.96-104
• /
• 1994

The use of advanced composite materials has grown in recent years in aerospace and other structures. Out of various kinds of repairing methods the one selecteh for this study is an idealized case which simulates a situation where a damaged laminate has been repaired by drilling a hole and therefter plugging the hole with reinforcement. Two typesof reinforcement are investigated ;adhesively bonged plug reinforcement or snug-fit unbonded plug in the hole. For each case of reinforcement, four different sizes of hole diameter and three types of reinforcing material(steel, aluminum, plexiglass) are employed for investigation. The experiment are mainloy forced on the evaluation of ultimate strength of laminate with reinforced hole in comparison to its counterpart with the open hole.

• 선박안전
• /
• 통권36호
• /
• pp.2-14
• /
• 2014

수중관람창의 판 두께산정식의 유효성을 판단하기 위하여 ISO기준과 일본기준을 비교하고 쌍동선에 설치되는 관람창의 안전성을 평가하기 위해 상용 유한요소해석 프로그램인 ABAQUS를 이용하여 Plexiglass의 두께를 산정하였다. 그 결과를 KS V ISO 12216:2005에 제시된 응력과 처짐에 의한 두께 산정 기준에 따라 관람창의 압력시험을 실시하여 유한요소해석의 적합성을 판단하였다. 또한, 선박과 관람창 연결부(Framing부)는 ISO 11336-1:2012(E)에서 제시된 6가지의 Type중 볼트가 체결된 4가지 경우에 대한 구조해석을 실시하여 연결부의 타입을 결정하였다.

• 한국광학회지
• /
• 제2권4호
• /
• pp.219-226
• /
• 1991

널리 쓰이는 금속들인 스테인레스강 304, 브라스, 알루미늄, 구리등의 얇은판을 기판에 붙여서, 광흡수를 무시할 수 있은 물질인 plexglass로 만든 광음향셀에 장착한 후 시료에 입사되는 광의 chopping 주파수를 변화시키며 시료에서 발생되는 광음향신호의 크기와 위상을 측정하고 Rosencwaig-Gersho(R-G) 이론에서 발전된 2층(two-layer)모델을 바탕으로한 파라메터 추정(parameter estimation)법을 이용하여 구조적으로 분석하여 열확산도(thermal diffusivity)와 열발산도(thermal effusivity)를 구하였다.

• Nuclear Engineering and Technology
• /
• 제55권11호
• /
• pp.4246-4251
• /
• 2023

The optimized design of a Neutron Activation Analysis (NAA) system, including Delayed Gamma NAA (DGNAA) and Prompt Gamma NAA (PGNAA), has been proposed in this research based on Mevex Linac with 5 MeV electron energy and 50 kW power as a neutron source. Based on the MCNPX 2.6 simulation, the optimized configuration contains; tungsten as an electron-photon converter, BeO as a photoneutron target, BeD₂ and plexiglass as moderators, and graphite as a reflector and collimator, as well as lead as a gamma shield. The obtained thermal neutron flux at the beam port is equal to 2.06 × 10⁹ (# /cm².s). In addition, using the optimized neutron beam, the detection limit has been calculated for some elements such as H-1, B-10, Na-23, Al-27, and Ti-48. The HPGe Coaxial detector has been used to measure gamma rays emitted by nuclides in the sample. By the results, the proposed system can be an appropriate solution to measure the concentration and toxicity of elements in different samples such as food, soil, and plant samples.

• The Journal of Advanced Prosthodontics
• /
• 제4권2호
• /
• pp.103-108
• /
• 2012

PURPOSE. Debonding of a composite resin core of the fiber post often occurs at the interface between these two materials. The aim of this study was to evaluate the effects of different surface treatment methods on bond strength between fiber posts and composite core. MATERIALS AND METHODS. Sixty-four fiber posts were picked in two groups (Hetco and Exacto). Each group was further divided into four subgroups using different surface treatments: 1) silanization; 2) sandblasting; 3) Treatment with 24% $H_2O_2$, and 4) no treatment (control group). A cylindrical plexiglass matrix was placed around the post and filled with the core resin composite. Specimens were stored in 5000 thermal cycles between $5^{\circ}C$ and $55^{\circ}C$. Tensile bond strength (TBS) test and evaluation using stereomicroscope were performed on the specimen and the data were analyzed using two-way ANOVA, Post Hoc Scheffe tests and Fisher's Exact Test (${\alpha}$=.05). RESULTS. There was a significant difference between the effect of different surface treatments on TBS ($P$ <.001) but different brands of post ($P$=.743) and interaction between the brand of post and surface treatment ($P$=.922) had no significant effect on TBS. Both silanization and sandblasting improved the bonding strength of fiber posts to composite resin core, but there were not any significant differences between these groups and control group. CONCLUSION. There was not any significant difference between two brands of fiber posts that had been used in this study. Although silanization and sandblasting can improve the TBS, there was not any significant differences between surface treatments used.

• 동아시아식생활학회지
• /
• 제7권1호
• /
• pp.13-20
• /
• 1997

This study was designed to determine the effects of protein sources on the curation of gastric ulceration, protein metabolism, and nitrogen balance in rats with gastric ulcer induce by restraint and water immersion stress. After the rats were fed 10% casein diet for 3 weeks, four groups of the rats were forced in 5$\times$5$\times$15cm plexiglass cage. The restraint and water immersion stress was carried at 20$\pm$2$^{\circ}C$ for 8-hour. The other one group(control group) was not exposed to stress. After stress 4 kinds of different diets containing 20% protein were given for 5 days. The protein sources were casein, whey protein, soy protein, gluten. The control group was fed to 10% casein diet. The results were as follows ; the weights of rats were not different among the diet groups During the experiment period follows ; the weights of rats were not different among the diet groups during the experiment period (for 5 days). The ulcer index of rats fed 10% gluten and soy protein diet was significantly higher than those of casein and whey protein diet groups(p<0.05). The level of serum albumin was not significantly different among diet groups. But hematocrit and the level of $\alpha$-amino-N, BU and UUN of plant protein diet groups were higher than animal diet groups, the urinary hydroxyproline of soy protein group was the highest and the whey protein was the lowest. The digestibility and BV of nitrogen of gluten diet group were significantly higher than those of casein and whey protein diet groups(p<0.05). The animal proteins had more curative effects of ulcer than plant animals. The results of this study provide useful information concerning diet therapy for the patients with gastrointestinal diseases and the field of enteral diet materials.