• Title/Summary/Keyword: flow control

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Effectiveness of Manual Therapy for Asthma in Children and Adolescents: A Systematic Review (소아·청소년 천식에 대한 수기요법의 효과: 체계적 문헌 고찰)

  • Park, Sun-Young;Heo, In;Shin, Byung-Cheul
    • The Journal of Churna Manual Medicine for Spine and Nerves
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    • v.17 no.1
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    • pp.11-19
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    • 2022
  • Objectives This systematic review aimed to provide evidence of the effectiveness and safety of manual therapy for asthma in children and adolescents. Methods We queried eight electronic databases (PubMed, Ovid-MEDLINE, EMBASE, The Cochrane Library, CNKI, ScienceON, KISS, and RISS) up to the end of April 2022. We included only randomized controlled trials (RCTs) investigating manual therapy for the treatment of asthma in children and adolescents. The methodological quality of the included RCTs was evaluated using the Cochrane risk-of-bias tool 1.0. Results Four RCTs were eligible for inclusion. Meta-analysis could not be performed due to the heterogeneity of the studies. One study showed the statistical significance of SMD 0.41 (95% CI: 0.06, 0.76, p<0.05) in the comparison with the osteopathic therapy group and the sham control group before and after treatment on the same day of peak expiratory flow. Conclusions This possibility was observed in a non-pharmacological approach to manual therapy. Manual therapy can be considered as an adjunct therapy for asthma treatment in children and adolescents who have difficulty with drug therapy.

Performance of Holstein cows subjected to different cooling sessions during subtropical summer

  • Bah, Musa;Javed, Khalid;Pasha, Talat Naseer;Shahid, Muhammad Qamer
    • Animal Bioscience
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    • v.35 no.11
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    • pp.1800-1807
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    • 2022
  • Objective: This study aimed to determine the effect of different cooling sessions (CSs) as a water conservation strategy on physiological, and production responses and welfare in Holstein Friesian cows during subtropical summer in Pakistan. Methods: Twenty-one cows were subjected to three CS in a completely randomized design. The treatments were: i) eleven hours continuous cooling with sprinklers - control (CNT), ii) four CS, and iii) two CS. The CNT represented the practices of the commercial dairy farms in the area, while the other CSs were used as water reduction strategies. Each CS lasted for 1 h with a 12 min cycle (3 min water on and 9 min off) with a sprinkler flow rate of 1.25 L/min. Results: The average temperature humidity index of the shed and the outside open area were 81.9 and 82.5, respectively. The results showed that both physiological responses were highest in the 2CS group followed by the CNT and the 4CS (p = 0.001). The CNT and 4CS groups had similar milk yield (p = 0.040). The 4CS group had more lying and eating times than the CNT and 2CS groups (p = 0.000). The cortisol level in the 2CS group was 2.0 and 2.2 ㎍/dL more than the CNT and the 4CS groups, respectively (p = 0.000). Conclusion: In conclusion, the 4CS was more efficient in cooling the cows and had better welfare, as it yielded similar milk yield, and better physiological responses than the CNT despite using 90% less water.

Evaluation on the Mechanical Performance and Microstructure of Cement Pastes Using Carbon Nanotube (탄소나노튜브 적용 시멘트 페이스트의 역학적 성능 및 미세구조 평가)

  • Chae-Ik, Lim;Se-Ho, Park;Won-Woo, Kim;Jae-Heum, Moon;Seung-Tae, Lee
    • Journal of the Korean Recycled Construction Resources Institute
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    • v.10 no.4
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    • pp.489-497
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    • 2022
  • In this study, the fluidity, mechanical properties and microstructure of cement pastes with carbon nanotube (CNT) were experimentally investigated. The 6 types of cement paste mixes with different PCE:CNT and w/b had been manufactured, and several tests including flow, compressive strength, absorption and water porosity were performed on cement pastes with or without CNT.Additionally, microstructural observations such as x-ray diffraction (XRD) and scanning electron microscopy (SEM) were carried out to examine hydrates formed in cement paste with CNT. As a result, it was found that the performance of cement pastes with CNT was better compared to that of control cement paste (OPC) due to both of hydration acceleration effect and filling effect. Furthermore, the SEM images clearly showed that CNT can bridge cracks formed in cement matrix. Conclusively, it is believed that the CNT, if mixed appropriately, could be an option as nono-materials to improve performance of concrete structures.

Prediction of Maneuverability of a Submarine at Surface Condition by Captive Model Test (구속모형시험을 통한 잠수함 선형의 수상 조건 조종성능 추정 연구)

  • Chang-Seop, Kwon;Dong-Jin, Kim;Young-Yeon, Lee;Yeon-Gyu, Kim;Kunhang, Yun;Sungrok, Cho
    • Journal of the Society of Naval Architects of Korea
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    • v.59 no.6
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    • pp.423-431
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    • 2022
  • In this paper, the results of Planar Motion Mechanism (PMM) test for a 1/15 scaled model of the MARIN Joubert BB2 submarine is dealt with to derive the maneuvering coefficients for surface condition. For the depth of surface navigation, the top of the sail was exposed 0.46 m above the water surface in the model scale, and it corresponds to 6.9 m in the full scale. The resistance and self-propulsion tests were conducted, and the model's self-propulsion point was obtained for 1.328 m/s, which corresponded to 10 knots in the full scale. The maneuvering tests were performed at the model's self-propulsion point, and the maneuvering coefficients were obtained. Based on the maneuvering coefficients, a turning simulation was performed for starboard 30 degree of stern fins. The straight-line stability and control effectiveness in the horizontal plane were analyzed using the maneuvering coefficients and compared with the appropriate range. For the analysis of the neutral fin angle of the X-type stern fin, the stern fin test with drift angles was carried out. As a result, the flow straightening effect at lower and upper parts of the stern fin was discussed.

A Study on the Simulation of Underground Acoustic Telemetry (지중 원격 음파통신 시뮬레이션 연구)

  • Shin, Younggy
    • Plant Journal
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    • v.18 no.2
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    • pp.41-45
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    • 2022
  • The conventional communication method using mud flow pressure waves has a speed of 1-2 bps, so it takes a long time to communicate, making real-time control impossible. Although the sound wave communication method for improving the communication speed by 10 times or more has been commercialized, its use is limited due to its high price and there are not many application cases. In this study, the simulator corresponding to the facility was developed to develop performance similar to the actual test results. For simulating sound wave communication through a drill pipe, we proposed a governing equation that can simulate friction damping by mud and developed a numerical analysis model. The attenuation factor was corrected by comparing it with the attenuation rate of sound wave energy at the drilling site. The developed numerical analysis model was applied to the QPSK modulation type communication algorithm to confirm the excellent performance of the communication error rate of 0.04% in the ground. This is the communication performance under the condition that noise has not been mixed yet, and in order to apply it, the technology of reproducing the actual noise signal for mixing by securing the field noise data was established.

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Galloping characteristics of a 1000-kV UHV iced transmission line in the full range of wind attack angles

  • Lou, Wenjuan;Wu, Huihui;Wen, Zuopeng;Liang, Hongchao
    • Wind and Structures
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    • v.34 no.2
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    • pp.173-183
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    • 2022
  • The galloping of iced conductors has long been a severe threat to the safety of overhead transmission lines. Compared with normal transmission lines, the ultra-high-voltage (UHV) transmission lines are more prone to galloping, and the damage caused is more severe. To control the galloping of UHV lines, it is necessary to conduct a comprehensive analysis of galloping characteristics. In this paper, a large-span 1000-kV UHV transmission line in China is taken as a practical example where an 8-bundled conductor with D-shaped icing is adopted. Galerkin method is employed for the time history calculation. For the wind attack angle range of 0°~180°, the galloping amplitudes in vertical, horizontal, and torsional directions are calculated. Furthermore, the vibration frequencies and galloping shapes are analyzed for the most severe conditions. The results show that the wind at 0°~10° attack angles can induce large torsional displacement, and this range of attack angles is also most likely to occur in reality. The galloping with largest amplitudes in all three directions occurs at the attack angle of 170° where the incoming flow is at the non-iced side, due to the strong aerodynamic instability. In addition, with wind speed increasing, galloping modes with higher frequencies appear and make the galloping shape more complex, indicating strong nonlinear behavior. Based on the galloping amplitudes of three directions, the full range of wind attack angles are divided into five galloping regions of different severity levels. The results obtained can promote the understanding of galloping and provide a reference for the anti-galloping design of UHV transmission lines.

Effect of rubber fiber size fraction on static and impact behavior of self-compacting concrete

  • Thakare, Akshay A.;Siddique, Salman;Singh, Amardeep;Gupta, Trilok;Chaudhary, Sandeep
    • Advances in concrete construction
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    • v.13 no.6
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    • pp.433-450
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    • 2022
  • The conventional disposal methods of waste tires are harmful to the environment. Moreover, the recycling/reuse of waste tires in domestic and industrial applications is limited due to parent product's quality control and environmental concerns. Additionally, the recycling industry often prefers powdered rubber particles (<0.60 mm). However, the processing of waste tires yields both powdered and coarser (>0.60 mm) size fractions. Reprocessing of coarser rubber requires higher energy increasing the product cost. Therefore, the waste tire rubber (WTR) less favored by the recycling industry is encouraged for use in construction products as one of the environment-friendly disposal methods. In this study, WTR fiber >0.60 mm size fraction is collected from the industry and sorted into 0.60-1.18, 1.18-2.36-, and 2.36-4.75-mm sizes. The effects of different fiber size fractions are studied by incorporating it as fine aggregates at 10%, 20%, and 30% in the self-compacting rubberized concrete (SCRC). The experimental investigations are carried out by performing fresh and hardened state tests. As the fresh state tests, the slump-flow, T500, V-funnel, and L-box are performed. As the hardened state tests, the scanning electron microscope, compressive strength, flexural strength and split tensile strength tests are conducted. Also, the water absorption, porosity, and ultrasonic pulse velocity tests are performed to measure durability. Furthermore, SCRC's energy absorption capacity is evaluated using the falling weight impact test. The statistical significance of content and size fraction of WTR fiber on SCRC is evaluated using the analysis of variance (ANOVA). As the general conclusion, implementation of various size fraction WTR fiber as fine aggregate showed potential for producing concrete for construction applications. Thus, use of WTR fiber in concrete is suggested for safe, and feasible waste tire disposal.

Analysis of Internal Flow and Control Speed for NH3 (Ammonia) Leakage Scenario of ALD Facility (ALD 설비의 NH3(Ammonia)누출 시나리오에 대한 내부유동 및 제어 속도 해석)

  • Lee, Seoung-Sam;An, Hyeong-hwan
    • Journal of the Korean Institute of Gas
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    • v.26 no.5
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    • pp.22-27
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    • 2022
  • Atomic Layer Deposition (ALD) is a facility that deposits an atomic layer on a wafer by causing a chemical reaction after decomposition using heat or plasma by inputting two or more gases during the semiconductor process. The main gas used at this time is NH3 (Ammonia). NH3 has a relatively narrow explosive range with an upper limit (UFL) of 33.6% and a lower limit (LEL) of 15%, but it can explode if a large amount suddenly gathers in one place. It is Velocity and fatal if inhaled or in contact with the skin. NH3 (Ammonia) of ALD (Atomic Layer Deposition) facility is supplied to the chamber through the gas inlet and discharged after the reaction.

TCST : A Technology for Verifying Control Flow Integrity for Smart Contracts within a Trusted Execution Environment (TCST : 신뢰실행환경 내에서 스마트 컨트랙트의 제어 흐름 무결성 검증을 위한 기술)

  • Park, Seonghwan;Kwon, Donghyun
    • Journal of the Korea Institute of Information Security & Cryptology
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    • v.32 no.6
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    • pp.1103-1112
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    • 2022
  • Blockchain technology is widespread in everyday life and various industry fields. It guarantees integrity and transparency between blockchain network participants through a distributed ledger. The smart contract is modifying and managing the distributed ledger, which is the most important component of guaranteeing integrity and transparency of blockchain network. Still, smart contracts are also a component of blockchain networks, it is disclosed to network participants transparently. For this reason, the vulnerability of smart contracts could be revealed easily. To mitigate this, various studies are leveraging TEE to guarantee the confidentiality of smart contracts. In existing studies, TEE provides confidentiality of smart contracts but guaranteeing the integrity of smart contracts is out of their scope. In this study, we provide not only the confidentiality of smart contracts but also their integrity, by guaranteeing the CFI of smart contracts within TEE.

Theoretical Heat Flow Analysis and Vibration Characteristics During Transportation of PCS(Power Conversion System) for Reliability (전력변환장치 캐비넷에서의 내부발열 개선을 위한 열유동 분석 및 유통안전성 향상을 위한 진동특성 분석)

  • Joo, Minjung;Suh, Sang Uk;Oh, Jae Young;Jung, Hyun-Mo;Park, Jong-Min
    • KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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    • v.28 no.2
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    • pp.143-149
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    • 2022
  • PCS needs to freely switch AC and DC to connect the battery, external AC loads and renewable energy in both directions for energy efficiency. Whenever converting happens, power loss inevitably occurs. Minimization of the power loss to save electricity and convert it for usage is a very critical function in PCS. PCS plays an important role in the ESS(Energy Storage System) but the importance of stabilizing semiconductors on PCB(Printed Circuit Board) should be empathized with a risk of failure such as a fire explosion. In this study, the temperature variation inside PCS was reviewed by cooling fan on top of PCS, and the vibration characteristics of PCS were analyzed during truck transportation for reliability of the product. In most cases, a cooling fan is mounted to control the inner temperature at the upper part of the PCS and components generating the heat placed on the internal aluminum cooling plate to apply the primary cooling and the secondary cooling system with inlet fans for the external air. Results of CFD showed slightly lack of circulating capacity but simulated temperatures were durable for components. The resonance points of PCS were various due to the complexity of components. Although they were less than 40 Hz which mostly occurs breakage, it was analyzed that the vibration displacement in the resonance frequency band was very insufficient. As a result of random-vibration simulation, the lower part was analyzed as the stress-concentrated point but no breakage was shown. The steel sheet could be stable for now, but for long-term domestic transportation, structural coupling may occur due to accumulation of fatigue strength. After the test completed, output voltage of the product had lost so that extra packaging such as bubble wrap should be considered.