It is essential for medical equipment sterilization operations to prevent infections in the hospital. The low temperature plasma sterilization method using oxygenated water has the advantage of high efficiency and short time in sterilizing processes. However, a chamber which can hold constant vacuum condition without deformation is essential in the sterilizing system to apply plasma sterilization technique. In this study, therefore, the vacuum chamber is developed for 70 liter plasma sterilization device. The vacuum chamber is designed by checking the thickness, edge fillet value and rib of chamber through each simulation. And the performance of the chamber is investigated by vibrational modes and heat stress simulation. The prototype vacuum chamber is tested by experiments to verify the safety and efficiency for 0.1 Torr vacuum, and the result shows the expected vacuum level and displacement.

This paper presents the approach of design parameters optimization based on Taguchi method for the uniformity of outlet pressure in a plasma discharge chamber. The key issue of a plasma discharge chamber is to have the uniformity of outlet pressure which can make a high performance of surface treatment. To extend the length of a outlet from 60mm to 250mm with the uniformity, This study optimally designed the middle holes, outlet width and height, and diameter of the second chamber by using SolidWorks and flow simulation tool. Simulation results demonstrate the validity of the proposed approach.

The potential use of UV-TiO2 photocatalytic oxidation absorbent reactor in the removal of gaseous formaldehyde was studied. This study was conducted inside a bench-type circulation reactor chamber at ambient air conditions. PCO (Photocatalytic Oxidaion) degradation test for formaldehyde was done repeatedly and the average was reported. It was evident that photocatalytic oxidation was proven to be an effective method to control indoor air pollutants, like formaldehyde in indoor air. However, by-products are produced in the case of formaldehyde degradation also CO2, CO, H2O and formic acid are produced. These by-products can inhibit the active site of the photocatalyst. Thus, addition of adsorbent succeeding the PCO-TiO2, acts as a secondary treatment wherein produced by-products from the degradation and unreacted HCHO will adhere to the surface of the adsorbent. In this study, synthetic zeolite and activated carbon pellets were used to control of by-products of formaldehyde. PCOTiO2 degradation alone achieves 86% for a period of 60 minutes. Addition of adsorbent improves the removal efficiency achieving 90% and 96% using activated carbon pellet and zeolite, respectively.

This paper is concerned with the optimal design of hyperbaric oxygen therapy system chamber with separated rooms for multi-users using stress analysis. Hyperbaric oxygen therapy is very important medical remedy for increasing the concentration of melted oxygen in human and animal body to recover the impaired cell for the healthy condition. This research proposed the proper procedures to design the physical specifications and investigate the mechanical design safety of hyperbaric oxygen chamber with two separated rooms using computational stress analysis with Solidworks program. The result of this research will be used to make the real size model of practical hyperbaric oxygen therapy system for multi-users with separated chamber.

This paper is concerned with the mechanical design of hyperbaric oxygen chamber for multi-users using stress analysis. HBOT(Hyperbaric Oxygen Therapy) is very effective medical equipment for increasing the concentration of melted oxygen in human and animal body. The hyperbaric oxygen supplies to the impaired cell of human and animal to recover the healthy condition. This research reported the design specifications and mechanical safety of hyperbaric oxygen chamber using computational stress analysis with CATIA program. The result from this research can be used for making the practical HBOT equipment for multi-users and to manufacture the real model

The air brake chamber is needed higher sealing performance and durability for the safety and confidential operation, especially, in brake systems of commercial vehicle. For higher sealing, we applied new clamping technique differentiated methods of other global manufacturers. And we developed the power spring and spring guide made from light engineering plastic with high durability in repeated condition. We also have achieved the basic performance test like sealing test in compressed air and various environment tests in dust and salty water for new manufactured air brake chambers. As a result, the air brake chamber applied light weight and high durable power spring is satisfied all demand specification conditions for commercial vehicle

본 연구에서는 파장의 위상차를 변화시켜 균일한 살균을 유도할 수 있고 저전력으로 효과를 높일 수 있는 QRD(quadratic residue diffusor) 마이크로파를 이용하여 챔버 내부의 위치에 따른 온도변화를 측정하여 효율성과 균등성을 분석한 결과는 다음과 같다. 챔버 내부의 수직 35cm, 중앙 위치에서는 7kW 조사시 가장 효율이 높게 나타났고, 좌우측 위치에서는 5kW에서 효율성이 높았다. 그리고 마그네트론 No. 1, 2, 3에서 3kW로 하였을 때, Bar의 위치에 따른 온도 균등성은 1Bar와 2Bar의 위치에서는 거의 비슷하게 나타났다. 마그네트론 No. 3, 4, 5의 3kW로 하였을 경우에는 3Bar에서 온도가 약 10~ 20% 정도 높게 나타났고 마그네트론 용량을 5, 7, 9kW로 하였을 때, 조사 시간에 대한 평균 온도는 Bar의 위치에 무관하게 거의 유사한 형태로 증가하였다. 반면에 챔버의 적정 내용적에 대한 효율성은 조사용량에 반드시 비례하지는 않았다. 마그네트론 3kW를 60, 120, 180초 동안 조사하였을 경우 마그네트론 조사 위치에 따라 구석 부분에서 약 5~10oC 더 높게 상승하였고 수평면의 위치별 온도 분포는 비교적 균일하였으며 부분적으로 구 석부분에서 약간 더 온도가 상승하는 경향이 있었다. 마그네트론 5, 7, 9kW 조사에서는 Bar의 위치와 상관없이 전반적으로 온도가 비교적 균일하게 상승하고 있었다.

Air Brake chamber is a core fucntional part delivering the brake force to drum brakes in hybrid commercial trucks. This part needs to have leakage prevention and durability for reliable operation. As an actuator by air pressure, there has to be no air leakeage, and because it is operated with high tention power spring, there has high durable spring head, that contacted power spring directly. In this study, a spring head was designed new size on weak points structually and simulated by structual simulation program. And, a flange and body tighten by clamp ring was simlated structual deformation by assembly torque and inner pressure. As a result, new desgned spring head has structual stablilty over 1.7～14.7% and deformation is in proprotion to inner pressure but the assembly torque of clamp ring is not related to deformation.

This paper is concerned with formulating the design specification and making hyperbaric oxygen chamber for multi-users. HBOT(Hyperbaric Oxygen Therapy) is very effective remedy for increasing the concentration of melted oxygen in human and animal body. The melted oxygen supplies to each cell in body to recover the normal condition. This research reported the design specifications and mechanical test results of hyperbaric oxygen chamber made with polyurethane as well as computational analysis with CATIA program. These data can set the physical dimensions of practical HBOT equipment for multi-users and be used to produce the effective commercial model.

LNGC 주기관의 크랭크 챔버 내 유증기 폭발 방지를 위해 기존의 이산화탄소 가스인젝터가 부착된 오일미스트 감지기 외에 불활성가스 시스템을 설치할 필요가 있다. 특히, LNGC 선박은 액체질소를 손쉽게 확보할 수 있는 장점이 있기 때문에 액체질소를 이용한 불활성가스 시스템을 도입하기 위한 설계 기초 단계로서 해석적 연구를 시행하였다. 또한 액체질소 최소 소모량 시스템을 개발하기 위하여 층상류 모델을 적용하였으며, 층상류 흐름에 미치는 유로관경, 포화압력과 선박동요에 따른 배관 기울기 등의 영향에 대해서도 조사하였다. 또한 질소와 같은 극저온 유체들과 여기에 사용된 예측 모델과의 비교 검토를 통하여 극저온 유체에 대해서도 모델의 유효성을 검증하였으며, 액체질소 불활성가스 시스템의 액체질소를 가스로 상변환 시키는데 소요되는 가열기의 열부하도 예측할 수 있었다.

There has been a growing concern about the emissions of formaldehyde and VOCs from automotive interior materials which could have an important impact on the in-vehicle air quality(IVAQ) of automotive vehicles. Many leading automobile manufacturers have now introduced their own specification standards for testing and limiting emissions from products produced by their suppliers. In addition, ISO (International Standard Organization) has been established ISO 12219-1, 2, 3, 4, 5 to determine the emissions of volatile organic compounds from automotive vehicle. The objective of this paper is to compare the area specific emission rates determined from surface emissions testing using the microchamber(MC) in comparison with a 1 m³ emission test chamber(ETC) operated in accordance with ISO 12219-3, ISO 12219-4. Measured emission concentrations in absolute terms were different between Microchamber and 1 m³ chamber. However, qualitative comparison of the chromatograms shows that the Microchamber is able to perform a screening test

This study was conducted to analyze the variations of air temperature, relative humidity and pressure in a low pressure chamber for plant growth. The low pressure chamber was composed of an acrylic cylinder, a stainless plate, a mass flow controller, an elastomer pressure controller, a read-out-box, a vacuum pump, and sensors of air temperature, relative humidity, and pressure. The pressure leakage in the low pressure chamber was greatly affected by the material and connection method of tubes. The leakage rate in the low pressure chamber with the welding of the stainless tubes and a plate decreased by 0.21kPa·h-1, whereas the leakage in the low pressure chamber with teflon tube and rubber O-ring was given by 1.03kPa·h-1. Pressure in the low pressure chamber was sensitively fluctuated by the air temperature inside the chamber. An elastomer pressure controller was installed to keep the pressure in the low pressure chamber at a setting value. However, inside relative humidity at dark period increased to saturation level.. Two levels (25 and 50kPa) of pressure and two levels (500 and 1,000sccm) of mass flow rate were provided to investigate the effect of low pressure and mass flow rate on relative humidity inside the chamber. It was concluded that low setting value of pressure and high mass flow rate of mixed gas were the effective methods to control the pressure and to suppress the excessive rise of relative humidity inside the chamber.

This study was performed to analysis the concentration of TVOC, 5VOC and formaldehyde for building material of total 262 using 20L test chamber. The concentration of TVOC, 5VOC and formaldehyde were measured 1.001㎎/㎡･h, 43.032㎍/㎡･h, 0.012㎎/㎡･h, respectively. TVOC concentration of paint and floor covering occupied the largest concentration of the indoor building materials as 2.689㎎/㎡･h, 2.120㎎/㎡･h, respectively. 5VOC concentration of floor covering was measured 106.636㎍/㎡･h. Toulene and xylene were occupied the largest part of the 5VOC as 51.2% and 33.1%, respectively. The concentration of formaldehyde for furniture materials occupied the largest concentration of the indoor building material as 0.072㎎/㎡h.

"Sick car syndrome" is known as a syndrome having latent health damage caused by complex smell of the assorted chemicals such as PVC and ABS which was components of new car interior trim (sheet, dashboard, audio case, cable, safety glass, synthetic rubber, and adhesive). The impact of interior trim on VOC levels was evaluated by testing with leather or fabric trims. Concentrations of VOCs and formaldehyde (HCHO) discharged from the car interior trims (2 sheet covers and 1 headliner) fixed in the sample holder of the small chamber were analyzed quantitatively and qualitatively. Concentrations of TVOC and HCHO emitted from 3 samples increased with increasing temperature and time. Concentration of TVOC emitted from PVC foam leather was highest under experimental conditions.

A ventilation system comprising a dielectric barrier discharger and UV‐TiO2 photocatalyst filters was designed and tested for simultaneous removal of gaseous and particulate contaminants in a test chamber. The DBD was used as the 1st stage of ESP for particle charging and gas decomposition. Charged particles were collected in the 2nd stage of ESP by an applied DC electric field. The UV‐TiO2 photocatalyst filters were used for decomposing gaseous species including O3 which was inherently produced by the DBD. Particle removal efficiencies based on mass and number were approximately 83.0% and 88.8%, respectively, after the ventilation system was operating for 5 hours. HCHO removal efficiency was approximately 100% for 1∼5ppm of upstream concentration condition. TVOC removal efficiency was 99.0% and 99.6% for 1 ppm and 5 ppm of upstream concentration conditions, respectively.

Fe nanopowders were successfully synthesized by plasma arc discharge (PAD) process using Fe rod. The influence of chamber pressure on the microstructure was investigated by means of X-ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FE-SEM), Transmission Electron Microscopy (TEM) and X-ray Photoelectron Spectroscopy (XPS). The prepared particles had nearly spherical shapes and consisted of metallic cores (a-Fe) and oxide shells (FeO), The powder size increased with increasing chamber pressure due to the higher dissolution and ejection rate of H and gas density in the molten metal.

강관이 매설되어 있는 폐쇄형 시스템에서 동결된 화강토의 온도분포에 관한 수치해석 및 실험적 연구가 수행되었다. 실험을 통해 측정된 부동수분량의 온도상관식을 제시하였으며, Lachenbruch의 열전도율 식을 사용하여 열전도율 측정값을 비교분석하였다. 원형 단면 강관이 매설된 모형토조의 동결챔버를 제작하여 동결토의 온도를 측정하고 유한요소 수치해석을 수행하여 실험 결과와 비교하였다. 수치해석시 동결된 화강토의 잠열효과가 고려되었다.