• Title/Summary/Keyword: fatigue safety

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Numerical Study on the Strength Safety of High Pressure Gas Cylinder (고압가스 압력용기의 강도안전성에 관한 수치해석적 연구)

  • Kim, Chung-Kyun;Kim, Seung-Chul
    • Journal of the Korean Institute of Gas
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    • v.14 no.2
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    • pp.1-6
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    • 2010
  • The strength safety of high pressure gas cylinder has been analyzed by using a finite element method. In this study, the internal gas pressures of a steel bombe include a service charging pressure of $9kg/cm^2$, high limit charging pressure of $18.6kg/cm^2$, high limit of safety valve operation pressure $24.5kg/cm^2$, and hydraulic testing pressure of $34.5kg/cm^2$. The computed FEM results indicate that the strength safety for a service charging pressure of $9kg/cm^2$ and high limit charging pressure of $18.6kg/cm^2$ is safe because the stress of a gas cylinder is within yield strength of steel. But the stress for a hydraulic testing pressure of $34.5kg/cm^2$ sufficiently exceeds the yield strength and remains under the tensile strength. If the hydraulic testing pressures frequently apply to the gas cylinder, the bombe may be fractured because a fatigue residual stress is accumulated on the lower round end plate due to a plastic deformation. The computed results show that the concentrated force in which is applied on a skirt zone does not affect to the lower round end plate, and the most weak zone of a bombe is a middle part of a lower round end plate between a bombe body and a skirt for a gas pressure. Thus, the FEM results show that the profile of a lower round end plate is an important design parameter of a high pressure gas cylinder.

Clinical study on safety of Scolopendrid aquacupuncture (오공약침의 안전성에 대한 임상적 연구)

  • So, Ki-suk;Choi, Hoi-kang;Park, So-young;Koh, Kang-hun;Kim, Sung-nam;Lee, Ok-ja;Yun, Min-young;Mun, Hyung-chul;Kim, Sung-chul;Lee, Jung-hun;Na, Won-kyung
    • Journal of Acupuncture Research
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    • v.21 no.1
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    • pp.136-148
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    • 2004
  • Objective: Recently scolopendrid aquacupuncture has been a good effect on pain control but it has not been known about clinical safety. So, In order to prove the clinical safety of scolopendrid aquacupuncture, We have observed the physical reac-tion and clinical pathology test after scolopendrid aquacupuncture treatment. Methods: We analyzed physical reaction and clinical pathology test before and after Scolopendrid aquacupuncture treatment of 30 patients suffering from pain, who admitted department of Acupunture and Moxibustion, College of Oriental Medicine, Won-Kwang University Kwangju hospital. Results & Conclusions: The results were summarized as follows. 1) The distribution of sex was 14 males and 16 females, and the average of patients age was 46.2 years. 2) The distribution of symptom was lumbago, lumbago with radiating pain, nuchal pain and knee joint pain. 3) In the 30 patients treated with Scolopendrid aquacupuncture, hematologic test did not show remarkable change. 4) In the 30 patients treated with Scolopendrid aquacupuncture, Liver function test(AST, ALT, ALP) showed a slight decrease on the contrary, and abnormal rate showed a decrease of 1.0%(from 3.3% to 2.3%) compared with previous study. 5) In the 30 patients treated with Scolopendrid aquacupuncture, Renal function test(BUN, Cr) and abnormal rate(from 2.5% to 2.0%) showed a slight decrease on the contrary. 6) In the 30 patients treated with Scolopendrid aquacupuncture. Electrolyte were normal range before & after treatment. 7) In the results of the Urine analysis of 30 patients, Leukocyte, Protein. Glucose, Keton, Bilirubin, U-bilinogen were not detected before and after Scolopendrid aquacupuncture treatment, and the rest almost made no difference. 8) In the Physical reactions, all of the patients complained of pain of body partially, only one patient showed reddish and itch, but symptoms like those were entirely disappeared within 24 hours and whole body pain, swelling, headache, dizziness, fatigue and nausea was not observed.

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A Survey of Adverse Events and Safety following Treatment of the Facial Cosmetic Acupuncture (Miso-Acupuncture) (안면미용침의 부작용 및 안전성에 대한 조사;시술자 23인을 중심으로)

  • Kwon, Seung-Koo;Lee, Yun-Kyu;Park, Seo-Young;Ko, Kyoung-Mo;Lee, Yoon-Kyoung;Kim, Jae-Su;Lee, Bong-Hyo;Lim, Seong-Chul;Jung, Tae-Young;Lee, Kyung-Min
    • Journal of Acupuncture Research
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    • v.25 no.1
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    • pp.199-209
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    • 2008
  • Objectives : To explore the adverse events and safety following facial cosmetic acupuncture treatment (Miso-Acupuncture). Subjects and methods : This study was a retrospective survey of practitioner's reports. The practitioners worked as facial cosmetic acupuncturists, gave informed consent, and completed a case report form between July and November of 2007. On this form, practitioners were asked to report the degree of adverse events relating to the Miso-Acupuncture, the total safety of the treatment, and reasons patients gave for quitting treatment. The practitioners in this study were all Oriental Medicine Doctors(OMD) who had trained at the Miso-Acupuncture Academy for 40 hours we received 23 final report cases. Results : In this study, adverse events following Miso-Acupuncture treatment were mild bruising(15 ; 65.2%), bleeding(12 ; 52.2%), pain(8 ; 34.8%), fatigue(7 ; 30.4%), headache(5 ; 21.7%), and others(10 ; 43.5%). The average degree of adverse events was between mild and moderate, which needs no extra treatment. The total safety of treatment for 16 weeks was between safe and nearly safe, and there was no need to quit treatment in spite of mild adverse events. Eight patients(34.8%) quit treatment, almost all for personal reasons unrelated to the Miso-Acupuncture. Conclusions : These results suggest that the Miso-Acupuncture has no serious adverse events and is a relatively safe treatment.

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Safety of Korean Medicine Treatment in Patients Vaccinated with the AstraZeneca COVID-19 Vaccine (ChAdOx1 nCoV-19/AZD1222): A Case Series (아스트라제네카 코로나19 백신(ChAdOx1 nCoV-19/AZD1222)을 접종한 환자에서 한방 치료의 안전성 : 사례군 연구)

  • Kang, Sung-woo;Hong, Sung-eun;Park, Ji-won;Kwon, Seungwon;Yoon, Sang-hyub;Kim, Kwan-il;Lee, Beom-joon;Jung, Hee-jae
    • The Journal of Internal Korean Medicine
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    • v.42 no.4
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    • pp.590-604
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    • 2021
  • Objectives: The purpose of this study is to examine the safety of Korean medicine treatment in patients vaccinated with the AstraZeneca COVID-19 vaccine (ChAdOx1 nCoV-19/AZD1222). Methods: We investigated patients at Kyung Hee University Korean Medicine Hospital who were vaccinated with the AstraZeneca COVID-19 vaccine between June 1, 2021 and June 30, 2021. The safety of Korean medicine treatment was evaluated by examining adverse events that occurred within seven days of vaccination, including liver function and kidney function testing, assessment of the severity of adverse events, and examination of causality to vaccines and Korean medicine treatment. Results: Eleven patients vaccinated with the first dose of the AstraZeneca COVID-19 vaccine were included. A total of 19 adverse events were reported: 15 systemic adverse events, three local adverse events, and one alanine aminotransferase increase. The most commonly reported systemic adverse events were fatigue (4 cases, 36.4%), headache (4 cases, 36.4%), and myalgia (4 cases, 36.4%). All adverse events were rated below moderate (grade 2) in severity. Systemic and local adverse events were evaluated as definitely related to vaccination and unlikely to be related to Korean medicine treatment, while alanine aminotransferase increase was evaluated as unlikely to be related to either the vaccine or Korean medicine treatment. Aspartate transaminase, Blood urea nitrogen, and creatinine were measured within the reference range after vaccination. Conclusion: Our results suggest that the severity and frequency of adverse events in patients vaccinated with the AstraZeneca COVID-19 vaccine did not increase after Korean medicine treatment.

A Study on Reliability Validation by Infrared Thermography of Composite Material Blade for Wind Turbine Generator (풍력발전용 복합소재 블레이드의 적외선 열화상 검사를 이용한 신뢰성 검증)

  • Kang, Byung Kwon;Nam, Mun Ho;Lim, Ik Sung
    • Journal of Applied Reliability
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    • v.14 no.3
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    • pp.176-181
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    • 2014
  • In these days, new and renewable energy is getting popular around globe and wind power generator is one of the renewable energy. In this study, we conducted a study on defect detection of composite material blade for wind power generator by applying active infrared thermography and produced a defect test piece by applying composite material used for blade of wind power generator. An infrared thermal camera and 2 kW halogen lamp are used for the purpose of research as equipments. Also, we analyzed temperature characteristic by using infrared thermal camera after checking a heat source on a test piece and found effectiveness of infrared thermography to blade of wind power generator by detecting defects resulting from temperature difference of a test piece, which eventually improve the safety and reliability of the composite material blade.

Evaluation of Residual Stress for Freight Car Wheel due to Wear and Brake Application (마모와 제동에 의한 화차륜의 잔류응력 변화)

  • Kwon, Seok Jin;Seo, Jung Won;Kim, Min Soo
    • Journal of the Korean Society for Precision Engineering
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    • v.33 no.7
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    • pp.529-534
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    • 2016
  • During the past few years, several incidents of freight car wheel failure during operation have occurred due to fatigue crack and overheating from braking. Tensile residual stress on the wheel tread creates an environment conducive to the formation of thermal cracks that may threaten the safety of train operations. It is important to investigate the residual stress on wheels in order to prevent derailment. In the present paper, the residual stress on wheels is measured using the x-ray diffraction system and the residual stress is analyzed using FEM. The result shows that the residual stress on the wheel rim is lower than that on the wheel tread center and the stress on over-braked wheels changes from compression residual stress to tensile residual stress.

Santalum album Linn wood and its oil: An aromatic Unani traditional medicine with versatile pharmacological activities

  • Sultana, Arshiya;Rahman, Khaleequr
    • CELLMED
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    • v.8 no.3
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    • pp.14.1-14.6
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    • 2018
  • Santalum album Linn. [Family: Santalaceae] is commonly known as white sandalwood, sandal safaid and safed chandan. It is one of the most valuable trees and second costliest wood in the world. Sandalwood and its oil is extensively used in the Unani and other traditional systems of medicine as it has blood purifier, anti-inflammatory, analgesic, exhilarant, cardiotonic, antiseptic, nervine tonic and expectorant properties. It is used in skin, cardiac, liver, gastrointestinal, respiratory, integument and urogenital disorders. These uses are supported and proven by many in vitro or in vivo studies. The proven pharmacological activities of S. album are antimicrobial, anti-oxidant, anti-inflammatory, antimutagenic and anti-fatigue. The research has proven that sandal oil or its constituents have anti-microbial activity. Sandalwood oil showed skin cancer preventive effect in mice and its constituent alpha santalol showed the anticancer property. The methanolic extract of wood was confirmed for antioxidant, free radical scavenging, analgesic and anti-inflammatory activities. ${\alpha}$ and ${\beta}$ santalols present in sandal oil showed sedative effects. Sandalwood tea had a significant effect on heart muscles of frog and showed increased myocardial contractility. Its oil showed significant changes in hepatic xenobiotic metabolizing enzymes. Sandalwood oil and its major constituents showed less acute oral and dermal toxicity in laboratory animals. Hence, the aforementioned studies justify the uses of sandalwood and its oil mentioned in the classical Unani literature. However, further clinical trials are suggested to confirm its efficacy and safety in humans.

A Theoretical Analysis of the Weak Shock Waves Propagating through a Bubbly Flow (기액 이상류를 전파하는 약한 충격파에 관한 이론해석적 연구)

  • Jun, Gu-Sik;Baek, Seung-Cheol;Kim, Heuy-Dong
    • Proceedings of the KSME Conference
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    • 2004.11a
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    • pp.1617-1622
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    • 2004
  • Two-phase flow of liquid and gas through pipe lines are frequently encountered in nuclear power plant or industrial facility. Pressure waves which can be generated by a valve operation or any other cause in pipe lines propagate through the two-phase flow, often leading to severe noise and vibration problems or fatigue failure of pipe line system. It is of practical importance to predict the propagation characteristics of the pressure waves for the safety design for the pipe line. In the present study, a theoretical analysis is performed to understand the propagation characteristics of a weak shock wave in a bubbly flow. A wave equation is developed using a small perturbation method to analyze the weak shock wave through a bubbly flow with comparably low void fractions. It is known that the elasticity of pipe and void fraction significantly affect the propagation speed of shock wave, but the frequency of relaxation oscillation which is generated behind the shock wave is not strongly influenced by the elasticity of pipe. The present analytical results are in close agreement with existing experimental data.

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Development of the Two-piece Aluminum Wheels Using the Friction Stir Welding (마찰교반용접법을 이용한 2피스 알루미늄 휠의 개발)

  • Choi, In-Young;Kang, Young-June;Kim, Andrey;Ahn, Kyu-Saeng
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.22 no.4
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    • pp.700-707
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    • 2013
  • Owing to high oil prices and environmental issues, the automobile industry has conducted considerable research and made large investments to manufacture a high-efficiency automobiles. In the case of automobile wheels in which a lightweight material is used to increase the fuel efficiency a mold is used to increase the production efficiency; however, the use of the molding method for this purpose is very expensive. Therefore an automobile wheel consists of two parts. In this study a two-piece automobile wheel is manufactured by the friction stir welding(FSW) of Al6061-T6 to reduce the manufacturing cost and process complexity. The FSW welding tool geometry and rotational speed, and the feed rate are key factors that significantly affect the weld strength. Therefore tensile tests were conducted on specimens produced using various welding conditions, and the optimal FSW welding conditions were applied to manufacture aluminum wheels. To ensure reliability, prototype aluminum wheels were manufactured and their mechanical reliability and safety were evaluated using a durability test, fatigue durability test, and impact test. Through this study, aluminum wheel production was made possible using the FSW method.

Dynamic Stress Analysis of Vehicle Frame Using a Nonlinear Finite Element Method

  • Kim, Gyu-Ha;Cho, Kyu-Zong;Chyun, In-Bum;Park, Seob
    • Journal of Mechanical Science and Technology
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    • v.17 no.10
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    • pp.1450-1457
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    • 2003
  • Structural integrity of either a passenger car or a light truck is one of the basic requirements for a full vehicle engineering and development program. The results of the vehicle product performance are measured in terms of durability, noise/vibration/harshness (NVH), crashworthiness and passenger safety. The level of performance of a vehicle directly affects the marketability, profitability and, most importantly, the future of the automobile manufacturer. In this study, we used the Virtual Proving Ground (VPG) approach for obtaining the dynamic stress or strain history and distribution. The VPG uses a nonlinear, dynamic, finite element code (LS-DYNA) which expands the application boundary outside classic linear, static assumptions. The VPG approach also uses realistic boundary conditions of tire/road surface interactions. To verify the predicted dynamic stress and fatigue critical region, a single bump run test, road load simulation, and field test have been performed. The prediction results were compared with experimental results, and the feasibility of the integrated life prediction methodology was verified.