The change in the performance of the range hood according to the pressure change was investigated through a comparative experiment, and the conclusion is as follows. KS C 9304: In 2020, static pressure was applied at 100 Pa according to the fan standard, and the test was conducted by varying the outlet diameter and power consumption. In the case of Motor power 55W, the air volume value was 184.6 when the outlet diameter was 125mm. As a result of the test, if the power consumption is 52.0W, the diameter of the outlet is 125mm, and the power consumption is 60.8W, and the diameter of the outlet is 100mm, it meets 160 or more and less than 200 (constant pressure 100Pa).

In this study, the structural integrity of the composite rocket motor case of a space launch vehicle was evaluated by conducting compression and bending tests. Two composite rocket motor case specimens with different stacking patterns were prepared for each test, and a dedicated jig was designed and manufactured. The test procedure was developed and applied separately for compression and bending tests. By performing these tests, the composite rocket motor case structural safety was assessed.

The influence of specimen geometry and notch on the hydrogen embrittlement of an SA372 steel for pressure vessels was investigated in this study. A slow strain-rate tensile (SSRT) test after the electrochemical hydrogen charging method was conducted on four types of tensile specimens with different directions, shapes (plate, round), and notches. The plate-type specimen showed a significant decrease in hydrogen embrittlement resistance owing to its large surface-to-volume ratio, compared to the round-type specimen. It is well established that most of the hydrogen distributes over the specimen surface when it is electrochemically charged. For the round-type specimens, the notched specimen showed increased hydrogen susceptibility compared with the unnotched one. A notch causes stress concentration and thus generates lots of dislocations in the locally deformed regions during the SSRT test. The solute hydrogen weakens the interactions between these dislocations by promoting the shielding effect of stress fields, which is called hydrogen-enhanced localized plasticity mechanisms. These results provide crucial insights into the relationship between specimen geometry and hydrogen embrittlement resistance.

우리나라 열병합 발전소에서 운영되고 있는 최신 증기터빈의 출력과 효율 향상을 위한 첫 번째 기술적인 진보는 고온, 고압의 증기를 사용할 수 있는 소재 개발의 진척이라고 할 수 있다. 소재의 발전과 더불어 증기터빈의 내부효율 향상을 위한 설계적 노력의 결실 로 높은 효율의 증기터빈이 제작되었다. 오랜 기간 운전 중인 증기터빈의 내부효율은 기계적 수명의 한계로 점차 손실이 발생하고 효율 과 출력이 떨어지게 된다. 이러한 이유로 본 연구에서는 상용프로그램을 이용하여 열병합 발전소용 고압(HP)-중압(IP) 증기터빈의 증기유 로 성능해석을 수행할 수 있는 모델을 개발하고 성능계산 방법을 제시하고자 한다. 증기터빈의 복잡한 성능계산방식으로 인해 증기터빈 실무자들에게 실질적으로 유용한 참고문헌이 될 수 있도록 주요 변수들을 제시하였다. 또한 증기터빈 성능계산에 필요한 열정산도 분석 과 증기터빈 성능계산 결과의 적합성을 성능시험 결과와 비교 확인하였다.

Gate valves are hydraulic components used to shut-off the water flow in water distribution systems. Gate valves may fail owing to various aspects such as leakage through seats, wearing of packing, and corrosion. Because it is considerably challenging to detect valve malfunctioning until the operator identifies a significant fault, failure of the gate valve may lead to a severe accident event associated with water distribution systems. In this study, we proposed a methodology to diagnose the faults of gate valves. To measure the pressure difference across a gate valve, two pressure transducers were installed before and after the gate valve in a pilot-scaled water distribution system. The obtained time-series pressure difference data were analyzed using a machine learning algorithm to diagnose faults. The validation of whether the flow rate of the pipeline can be predicted based on the pressure difference between the upstream and downstream sides of the valve was also performed.

Porous carbons are considered promising for CO2 capture due to their high-pressure capture performance, high chemical/ thermal stability, and low humidity sensitivity. But, their low-pressure capture performance, selectivity toward CO2 over N2, and adsorption kinetics need further improvement for practical applications. Herein, we report a novel dual-templating strategy based on molten salts (LiBr/KBr) and hydrogen-bonded triazine molecules (melamine–cyanuric acid complex, MCA) to prepare high-performance porous carbon adsorbents for low-pressure CO2. The comprehensive investigations of pore structure, microstructure, and chemical structure, as well as their correlation with CO2 capture performance, reveal that the dual template plays the role of porogen for multi-hierarchical porous structure based on supermicro-/micro-/meso-/ macro-pores and reactant for high N/O insertion into the carbon framework. Furthermore, they exert a synergistic but independent effect on the carbonization procedure of glucose, avoiding the counter-balance between porous structure and hetero-atom insertion. This enables the preferred formation of pyrrolic N/carboxylic acid functional groups and supermicropores of ~ 0.8 nm, while retaining the micro-/meso-/macro-pores (> 1 nm) more than 60% of the total pore volume. As a result, the dual-templated porous carbon adsorbent (MG-Br-600) simultaneously achieves a high CO2 capture capacity of 3.95 mmol g− 1 at 850 Torr and 0 °C, a CO2/ N2 (15:85) selectivity factor of 31 at 0 °C, and a high intra-particle diffusivity of 0.23 mmol g− 1 min− 0.5 without performance degradation over repeated use. With the molecular scale structure tunability and the large-scale production capability, the dual-templating strategy will offer versatile tools for designing high-performance carbon-based adsorbents for CO2 capture.

Level measurement of liquid radwaste is essential for inventory management of treatment system. Among various methods, level measurement based on differential pressure has many advantages. First, it is possible to measure the liquid level of the system regardless of liquid type. Second, as the instrument doesn’t need to be installed near the tank, there is no need to contact the tank when managing it. Therefore, workers’ radiation dose from the system can be decreased. Finally, although it depends on the accuracy, the price of the instrument is relatively low. With these advantages, in general, liquid radwaste level in a tank is measured using differential pressure in the treatment system. Not only the advantages described above, there are some disadvantages. As the liquid in the system is waste, it is not pure but has some suspended materials. These materials can be accumulated in tanks and pipes where the liquids move to come into direct contact with pneumatic pipes that are essential in differential pressure instruments. As a result, in case of a treatment using heat source, the accumulated materials may become sludge causing interference in pneumatic pipes. And this can change the pressure which also affects the level measured. In conclusion, in case of liquid storage tanks in which the situation cannot be checked, the proficiency of an operator becomes important.

Backfill is one of the key elements of deep geological disposal. The backfill material is used to fill disposal tunnels and is mainly composed of swellable clay, preventing the migration of nuclide and structurally supporting the tunnel. The selection and application of backfill material are critical for the stable and efficient disposal of spent fuel. Therefore, it is essential to secure various candidate materials for backfill and to comprehensively understand the properties and behavior of these materials. Recently, the Korea Atomic Energy Research Institute has selected a candidate material called Bentonil-WRK and is evaluating its applicability. To utilize this material as backfill, the safety function of a mixed backfill concept, consisting of sand and Bentonil-WRK, was assessed. The swelling pressure was measured as a function of dry density for a bentonite/silica sand mix ratio of 3/7. The results showed that the swelling pressure ranged from 0.15 to 0.273 MPa, depending on the dry density, with higher dry densities resulting in higher swelling pressures. The measured swelling pressure met the target performance criteria suggested by SKB and Posiva (i. e., 0.1 MPa), but did not meet the design requirement for swelling pressure (i. e., 1 MPa). This indicate the need for further research after increasing the mass fraction of bentonite (e. g., mix ratio 4/6 or more). The results of this study are expected to be used in the selection of candidate backfill materials and the establishment of design guidelines for engineered barrier backfill.

In the event of a loss of a SNF (spent nuclear fuel) transport cask during maritime transportation, it is essential to evaluate the critical depth at which the integrity of the cask can be maintained under high water pressure. SNF transport casks are classified as Type B containers and the integrity of of the containment boundary must be maintained up to a depth of 200 meters unless the containment boundary was breached under beyond-design basis accidents. However, if an intact SNF cask is lost at a depth deeper than 200-meter, release of radioactive material may occur due to breach of containment boundary with over-pressure. In this study, we developed a code for the evaluation of the pressure limit of SNF transport cask, which can be evaluated by inputting the main dimensions and loading conditions of cask. The evaluation model was coded as a computer module for ease of use. In the previous study, models with three different fidelities were developed to ensure the reliability of the calculation and maintain sufficient flexibility to deal with various input conditions. Those three models consisted of a high-fidelity model that provided the most realistic response, a low-fidelity model with parameterized simplified geometry, and a mathematical model based on the shell theory. The maximum stress evaluation of the three models confirmed that the mathematical model provides the most conservative results than the other two models. The previous results demonstrate that mathematical models can be used in the code of computer modules. In this study, additional models of transport cask were created using parametric modeling techniques to improve the accuracy of the pressure limit assessment code for different cask and situations. The same boundary conditions and loading conditions were imposed as in the previous simplified model, and the maximum stress results considering the change in the shape of the transport container were derived and compared with the mathematical model. The comparison results showed that the mathematical model had more conservative values than the simplified model even under various input conditions. Accordingly, we applied the mathematical model to develop a transportation container pressure limit evaluation code that can be simulated in various situations such as shape change and various situations.

In this paper, we report and discuss the semi-permanently hydrophilic (SPH) treatment of polyester fabric using plasma polymerization and oxidation based on atmospheric pressure dielectric barrier discharge (APDBD) technology. SiOxCy (-H) was coated on polyester fabric using Hexamethylcyclotrisiloxane (HMCTSO) as a precursor, and then plasma oxidation was performed to change the upper layer of the thin film to SiO2-like. The degradation of hydrophilicity of the SPH polyester fabrics was evaluated by water contact angle (WCA) and wicking time after repeated washing. The surface morphology of the coated yarns was observed with scanning electron microscopy, and the presence of the coating layer was confirmed by measuring the Si peak using energy dispersive x-ray spectroscopy. The WCA of the SPH polyester fabric increased to 50 degrees after 30 washes, but it was still hydrophilic compared to the untreated fabric. The decrease in hydrophilicity of the SPH fabric was due to peeling of the SiOxCy(-H) thin film coated on polyester yarns.

목적 : 본 연구는 휠체어 사용자의 욕창 예방을 위한 센서 기반 방석에 대한 선행 문헌을 분석하여 센서의 위치, 개수, 적 용 대상자를 알아보고자 하였다. 연구방법 : PRISMA(Preferred Reporting Items for Systematic Review and Meta-Analysis) 연구방법을 통해 IEEE Xplore, PubMed, Embase 등 데이터베이스에서 2010년부터 2021년까지 게재된 논문을 선정기준을 근거로 논문을 선정 하였다. 최종적으로 총 9편의 문헌이 선정되었으며, 각 문헌을 분석하였다. 결과 : 연구 대상자의 특성은 척수 손상 환자에 관한 연구가 4편으로 가장 많았으며, 비장애인은 3편, 다발성 경화증 환자 는 1편으로 보고되었다. 대상자의 수는 비장애인의 경우 8명에서 32명으로, 장애인의 경우 1명에서 17명으로 조사되었 다. 센서의 개수는 3개에서 1,024개로 다양하게 보고되었다. 센서는 주로 방석에만 삽입된 연구들이 조사됐지만, 등판에 도 센서를 삽입한 연구가 2편이 있었다. 센서의 위치를 쉽게 파악할 수 있도록 시각화된 자료도 함께 제시하였다. 앉은 자세 또는 활동 수준을 분류하는 연구가 가장 많았으며, 사용된 기기들의 정확도는 높은 것으로 조사되었다. 결론 : 센서 기반 방석을 설계할 때 센서의 위치는 욕창이 주로 발생하는 부위를 고려해야 하며, 압력 측정 외에도 알람 시스템을 통해 욕창 위험성에 관한 정보를 제공해야 한다고 사료된다. 클라이언트의 특성을 고려한 요인들을 제품에 반 영해야 하며, 임상가의 전문적인 서비스도 함께 이루어져야 한다. 클라이언트 중심의 접근과 근거 기반의 접근은 센서 기 반의 방석 개발과 중재에서도 중요한 요소이다. 본 연구는 센서 기반의 방석 개발에 있어 기초자료로 활용될 수 있을 것 으로 사료된다.

Background: Technological developments have led to the creation of a mechanical device capable of providing a representative massage as a passive treatment. The use of mechanical massage offers the distinct advantage of being user-friendly and available for use at any given time. Objectives: To investigated present the outcomes of utilizing a massage bed on the range of motion (ROM) and pressure pain threshold (PPT) in patients diagnosed with chronic low back pain. Design: ABA design of a single case study. Methods: To measure the ROM of the subject's trunk flexion, extension, lateral flexion, and rotation, a tape measure and goniometer were utilized. Furthermore, PPT was measured using an electronic pressure pain meter. Baseline A and Baseline A’ periods were conducted for 5 consecutive days without intervention. Following the baseline periods, a massage bed intervention was administered for 1 hour daily for a total of 10 days during the Intervention B period. Daily assessments were performed, and the Intervention B period was conducted after the intervention. Results: The ROM effect was confirmed in trunk lateral flexion and rotation, while the PPT was effective in both L1, right L2, left L4, and left L5. Conclusion: The results of this study confirmed that the use of a massage bed improved the ROM and PPT in patients suffering from chronic back pain. Further randomized controlled trials involving a larger sample size are necessary to validate these findings.

Background: Despite its high prevalence, interventions in plantar fasciitis remain inconclusive. To improve the daily life of plantar fasciitis patients, it is necessary to identify appropriate interventions to improve pain and foot pressure and balance. Improving the interventions for plantar fasciitis is one of the main goals for rehabilitation. Objectives: To investigate the changes in pain and static-dynamic foot pressure and balance through the evaluation of 42 plantar fasciitis patient before and after the foot stretching and joint mobilization interventions. Design: Randomized controlled trial. Methods: The 42 subjects of the study were divided into a stretching group and a joint mobilization group with 21 subjects being assigned to each group. The results before and after the experiment were analyzed by applying stretching and joint movement interventions for a total of 6 weeks. Results: Before and after the intervention, there were significant improvements in the pain index and static-dynamic foot pressure and static balance in both stretching and joint mobilization groups. However, the between-group comparison indicated no significant differences. Conclusion: The stretching and the joint mobilization can improve the pain and static-dynamic foot pressure and static balance in plantar fasciitis patients.

This study aims to measure sedimentation status change with the changes in internal pressure for dry chemical extinguishers of various use periods and analyze the suitability of the fire extinguishers' performance criteria. When the internal pressure of the fire extinguisher is 0%, 2 out of 10 new dry chemical powders for the 5 elapsed years were noted to be suitable, including 3 recycled dry chemical powders with 5 elapsed years that were found eligible. One out of 10 new dry chemical powders for 10 elapsed years was shown as suitable. Also, one new dry chemical powder for 13 elapsed years was suitable. When the internal pressure of the fire extinguisher was 50%, all 10 out of 10 new dry chemical powders for 5 years, recycled one with 5 elapsed years, and a new one with 10 elapsed years were found to be suitable, while 9 new dry chemical powders for 13 years were shown as suitable. When the internal pressure of the fire extinguisher was normal, new ones with 5 elapsed years, recycled ones with 5 elapsed years, new ones with 10 elapsed years, and new ones with 13 elapsed years were all 10 out of 10 samples noted as suitable. In summarizing the experiment results, it was found that the sedimentation status, one of the fire extinguisher's physical properties experiments, affects the fire extinguisher's performance criteria rather than the change with use periods.

Determination of explosion reference pressure is important in designing and testing flameproof enclosures (Ex d). Although relative humidity affects to explosion pressure, its effect is not well investigated for the gas group IIB, IIA, and I. This study tested explosion pressure for Ethylene (8 vol.%), Propane (4.6 vol.%), and Methane (9.8 vol.%), which are the representative gas of the gas group IIB, IIA, and I, at ambient temperature and atmospheric pressure (1 atm) under different relative humidity (0% ~ 80%). Ethylene- and Propane-air mixed gases generally tended to decrease as the relative humidity increased; however, explosion pressure was largely dropped at 20% of relative humidity compared to 0% and 10% of relative humidity. On the other hand, Methane-air mixture gas showed similar pressures at 0% and 10% of relative humidity; but no explosion occurred at more than 20%. The results of this study can be used in setting a testing protocol of explosion reference pressure for designing and testing a flameproof enclosure.