• Title/Summary/Keyword: Endurance

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A Study of the Endurance Severity for Automobile Wheel Safety Standard Revision (자동차 휠 안전기준 개정 대응을 위한 내구 가혹도 검토)

  • Jang, JinHee;Heo, SungPil
    • Journal of Auto-vehicle Safety Association
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    • v.14 no.3
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    • pp.30-34
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    • 2022
  • The CFT(Cornering Fatigue test) and RFT(Radial Fatigue Test) are tests for evaluating the endurance of the disc and rim region of the wheel. In recent, automobile wheel safety standards have been revised and the applied load and target life criteria are different from existing conditions. The verification evaluation of all wheels requires a lot of time and cost. In this study, the endurance severity of each test was compared through strain-life approach by selecting 4 steel and 8 aluminum wheels.

A prototype to improve endurance of solar powered aircraft using MPPT and rechargeable battery

  • Leo Paul Amuthan George;Anju Anna Jacob
    • Advances in aircraft and spacecraft science
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    • v.11 no.1
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    • pp.23-31
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    • 2024
  • This paper addresses the enhancement of long-endurance solar-powered aircraft through the integration of a rechargeable battery and Maximum Power Point Tracking (MPPT) controller. Traditional long-endurance aircraft often rely on non-renewable energy sourcessuch as batteries orjetfuel, contributing to carbon emissions. The proposed system aims to mitigate these environmental impacts by harnessing solar energy and efficiently managing its storage and utilization. The MPPT controller optimizes the power output of photovoltaic cells, enabling simultaneous charging and discharging of the battery for propulsion and servo control. A prototype is presented to illustrate the practical implementation and functionality of the proposed design, marking a promising step towards more sustainable and enduring solar-powered flight.

Effects of the NADPH Oxidase p22phox C242T Polymorphism on Endurance Exercise Performance and Oxidative DNA Damage in Response to Aerobic Exercise Training

  • Paik, Il-Young;Jin, Chan-Ho;Jin, Hwa-Eun;Kim, Young-Il;Cho, Su-Youn;Roh, Hee-Tae;Suh, Ah-Ram;Suh, Sang-Hoon
    • Molecules and Cells
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    • v.27 no.5
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    • pp.557-562
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    • 2009
  • We examined the effects of the NADPH oxidase p22phox C242T polymorphism on endurance exercise performance and oxidative DNA damage in response to acute and chronic exercises. One hundred three subjects were recruited, among which 26 healthy subjects (CC: 12, TC: 12, and TT: 2) were studied during rest, exercise at 85% $VO_2max$, and recovery before and after 8 weeks of treadmill running. Lymphocyte DNA damage increased significantly in response to exercise (p < 0.05). There were no significant differences in plasma MDA, SOD concentrations and lymphocyte DNA damage between CC genotype and T allele group, but significant endurance training differences were observed. Endurance training increased exercise time to exhaustion in both the CC genotype and T allele groups (p < 0.05) but no significant difference was found between groups. The results of the current study with young, healthy, Korean men are interpreted to mean that 1) the majority had the CC genotype of the NADPH oxidase p22phox C242T polymorphism (82.5%: CC, 15.5%: TC, 1.9%: TT), 2) acute exercise increased lymphocyte DNA damage, 3) endurance training significantly increased exercise time to exhaustion, and alleviated lymphocyte DNA damage, and 4) The NADPH oxidase p22phox C242T polymorphism, however, did not alter lymphocyte DNA damage or exercise performance at rest, immediately after exercise, or during recovery.

Correlation between Balance Ability, Muscle Strength, and Muscle Endurance, in Taekwondo, Soccer, and Gymnastics Athletes (태권도, 축구, 체조 선수들의 균형능력과 근력, 근지구력의 상관분석)

  • Park, Seok-Woo;Ryu, Young;Kim, Kew-Wan
    • Korean Journal of Applied Biomechanics
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    • v.24 no.1
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    • pp.85-93
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    • 2014
  • The purpose of this study was to investigate a relationship among Taekwondo, soccer and gymnastic athletes their balance ability and lower extremity muscle strength, muscle endurance and also whether these variables show differences by sports type. For this purpose, 10 Taekwondo athletes, 10 soccer athletes and 10 gymnastic athletes that is a high school in I area were selected and their balance ability, isokinetic muscle strength and muscle endurance were measured by using force platform (AMTI) and isokinetic measurement (HUMAC NORM). Then the following results were obtained by conducting pearson product-moment correlation analysis and one-way ANOVA. In case of both right and left foot one-leg standing with open-eyes, there was a relation between both knee extension maximal muscle strength of Taekwondo, soccer, gymnastic athletes and balance ability, and in case of right foot one-leg standing with open-eyes, there was a relation between that is right plantar flexion and dorsi flexion maximum muscle strength and muscle endurance of Taekwondo, soccer, gymnastic athletes and their balance ability. Furthermore, in case of left dorsi flexion maximum muscle strength, there were significant differences in order of Taekwondo, gymnastics and soccer, and for isokinetic plantar flexion maximum muscle endurance, both right and left showed significant differences in order of Taekwondo, gymnastic and soccer.

Effects of Proprioceptive Neuromuscular Facilitation Exercises on the Neck Disability Index and Deep Neck Flexor Endurance of Patients with Acute Whiplash Injury (고유수용성신경근촉진법 운동이 급성 목부염좌 환자의 통증과 목 장애지수 및 심부목굽힘근 지구력에 미치는 영향)

  • Kang, Tae-Woo;Jeong, Wang-Mo;Kim, Beom-Ryong
    • PNF and Movement
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    • v.16 no.2
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    • pp.217-227
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    • 2018
  • Purpose: The purpose of this study is to examine the effects of proprioceptive neuromuscular facilitation (PNF) exercises on the neck disability index and deep neck flexor endurance of acute whiplash injury patients and to provide basic data for PNF exercises for musculoskeletal system disorder patients. Methods: Twenty acute whiplash injury patients were randomly assigned to an experimental group (n=10) and were treated with PNF exercises whereas a control group (n=10) underwent general exercises. Each session lasted 15 minutes and was performed five times a week for two weeks. The degree of pain was assessed using a visual analogue scale (VAS) and the degree of neck disability was measured by the neck disability index (NDI). Craniocervical flexor endurance (CCFE) tests were conducted to measure deep neck flexor endurance. Results: In terms of the intragroup changes in VAS, NDI, and CCFE, there were significant decreases in both the experimental and the control groups. After intervention, there were significant differences between the experimental group and the control group in terms of intergroup changes in VAS, NDI and CCFE. Conclusion: Although the exercises that are generally applied to acute whiplash injury patients are effective on the whole, PNF exercises are considered to be beneficial, given the improvements in the neck disability index and deep neck flexor endurance.

The Effect of Functional Postural Trunk Exercise on Pain, Activities of Daily Living, Range of Motion, Deep Cranio-cervical Flexor Muscle Endurance in Neck Pain Patient by Acute Whiplash-Associated Disorders (체간의 기능적 자세운동이 급성 편타성-관련손상에 의한 경부통 환자의 통증과 기능장애수준, 관절가동범위, 두경부 심부굴곡근 지구력에 미치는 영향)

  • Choi, Hyun-Woong;Kim, Suhn-Yeop
    • Journal of the Korean Society of Physical Medicine
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    • v.8 no.4
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    • pp.655-666
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    • 2013
  • PURPOSE: The main objective of this study is observing the effects of the functional postural trunk exercise (FPTE) on deep cranio-cervical flexor (CCF) muscle endurance applied on neck pain patients suffering from the acute whiplash-association disorder (WAD). METHODS: The study was tested with 47 patients with neck pain. All patients were equally treated with the ordinary therapy, only experimental group (n=23) was treated with FPTE: assumption of an upright lumbo-pelvic and spinal postural position, adding a neck lengthening manoeuvre in addition. Patients attended physical therapy for 3 times a week, for 4 weeks. Visual analogue scale (VAS) for pain, neck disability index (NDI), range of motion (ROM), were recorded both before and after the intervention. Also muscle activity in the CCF test was employed to analyze the changes between before and after. RESULT: After 4 weeks of training intervention, a remarkable increase in muscle endurance, rotation, extension ROM (p<.05) and decrease in pain and NDI (p<.05) in both groups. Further, the differences between groups were muscle endurance (F=60.350, p<.01), pain, and the left rotation ROM (p<.05). CONCLUSION: From the results, the experimental group had significant the increase in muscle endurance, and the significant decrease in pain. Whilst further research in this category is necessary, these observations suggest that applying exercise in early diagnosis can be of help to treat the neck pain patients suffering from the WAD.

Analysis of correlation between the inspiratory capacity of the National softball players and the bone density, bon mass, muscle power, muscle endurance (국가대표 소프트볼선수들의 흡기능력과 골밀도 및 골 질량 그리고 체간의 근력 및 근지구력의 상관관계 분석)

  • Kim, Hyun Chul;Park, Ki Jun
    • Journal of the Korean Society of Physical Medicine
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    • v.15 no.1
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    • pp.95-104
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    • 2020
  • PURPOSE: A prospective study was conducted to investigate the correlation between the inspiration ability, bone mineral density, lumbar muscle strength, and muscular endurance for the national softball athletes in the national training center. METHODS: The general characteristics of study subjects, inspiration ability, bone mineral density, muscle strength, and muscular endurance data were analyzed using descriptive statistics. In addition, the Pearson product moment correlation was performed to investigate the correlation between the inspiratory capacity, bone mineral density, muscle strength, and muscular endurance. RESULTS: The inspiration, flow rates, and volume were not correlated with the bone mass and bone mineral density. Inspiration and the flow rates and volume were not correlated with the bone mass and bone mineral density. On the other hand, inspiration was correlated with the Extensor muscles (r=.464, p=.006) at an angular velocity of 60°/s and the flexors (r=.463, p=.006) and extensor muscles (r=.615, p<.001) at an angular velocity of 180°/s. The flow rate was also correlated with the extensor muscles (r=.444, p=.009) at an angular velocity of 60°/s and with flexor muscles (r=.432, p=.011) and extensor muscles (r=.589, p<.001) at an angular velocity of 180°/s. Finally, the volume was correlated at the extensor muscles at an angular velocity of 180°/s (r=.534, p=.001). CONCLUSION: The correlation between the inspiratory capacity, bone mineral density, muscle strength, and muscular endurance of softball athletes did not correlate with the bone mass and bone density. On the other hand, the lumbar muscle strength increased with increasing inspiratory capacity.

Effect of Aging on Adhesive Strength of Rubber-steel Cord Composite and Tire-endurance (고무-스틸 코드 접착력과 타이어 내구력에 미치는 노화의 영향)

  • Lim, Won-Woo
    • Journal of Adhesion and Interface
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    • v.3 no.2
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    • pp.40-44
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    • 2002
  • We invested effect of the keeping-time of uncured composite and thermal aging, of cured composite on adhesive strength for rubber-brass coated steel cord composite in this study. We also evaluated how the adhesive strength affects to tire endurance. Using PAD adhesion specimen, peel adhesive strength was measured. The uncured composite was kept for several days up to 35 days in factory. Cured composite was also kept for 5 and 10 days at $85^{\circ}C$ in dry oven. Peel adhesive strength was decreased with increasing keeping-time and showed lower value with increasing thermal aging time. The lower peel adhesive strength, the lower tire-endurance. This fact was caused by the humidity and thermal aging which affected in the decrease of adhesive strength of the rubber-steel cord composite and resulted in interface fracture between rubber and steel cord. This phenomenon was confirmed from SEM investigation and tire-endurance. It was just known that corrosion of steel cord's surface and aging of adhesive layer strongly affected to decrease of adhesive strength. This resulted in directly decreasing tire-endurance.

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Effects of Endurance Training on the Serum Levels of Tumour Necrosis Factor-${\alpha}$ and Interferon-${\gamma}$ in Sedentary Men

  • Jahromi, Abdolreza Sotoodeh;Zar, Abdossaleh;Ahmadi, Fatemeh;Krustrup, Peter;Ebrahim, Khosrow;Hovanloo, Friborz;Amani, Davar
    • IMMUNE NETWORK
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    • v.14 no.5
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    • pp.255-259
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    • 2014
  • Physical activity could be considered one of the factors that affect the immune system status and function. To find the relation between exercise and cytokines, we examined the possible effects of an 8-week endurance training program on the serum levels of cytokines, including tumour necrosis factor-alpha (TNF-${\alpha}$) and interferon-gamma (IFN-${\gamma}$) in sedentary men. A total of 30 healthy young male volunteers were randomly divided into an endurance training group and a control group. The training group followed a specific exercise protocol (running on a treadmill for 15~30 min at 50~70% maximal heart rate) for 8 weeks and the control group did not participate in any exercise program. Venous blood samples were collected from both the groups 24 h before and 24 h and 48 h after the exercise. Repeated ANOVA was used for statistical purposes. The serum levels of TNF-${\alpha}$ and IFN-${\gamma}$ were determined by ELISA. Significant (p<0.05) and non-significant (p>0.05) decreases were observed in the serum levels of IFN-${\gamma}$ and TNF-${\alpha}$, respectively, after the 8-week endurance training program. Our findings indicated that an 8-week endurance exercise may affect the serum levels of some inflammatory cytokines, suggesting the beneficial role of this training protocol in elderly population and people with certain conditions (inflammation of the vertebrae or other inflammatory diseases).

Erasing Methods for Improved Endurance Characteristics in Single-Poly EEPROM (단층 다결정실리콘 EEPROM의 Endurance 특성 개선을 위한 소거방법)

  • Yu, Yeong-Cheol;Jang, Seong-Jun;Yu, Jong-Geun;Lee, Gwang-Yeop;Kim, Yeong-Seok;Park, Jong-Tae
    • Journal of the Korean Institute of Telematics and Electronics D
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    • v.36D no.6
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    • pp.21-27
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    • 1999
  • In this work, single-poly EEPROM was designed and fabricated by using standard $0.8{\mu}m$ CMOS process. From the results of programming and erasing characteristics, it was found that the programming time was smaller than 10ms and the erasing time was about 100ms. To reduce the erasing time, several erasing methods were performed. The S/D erasing method was used to improve the endurance characteristics which was degraded due to electron trapping in programming and erasing cycles. By using the S/D erasing method, the more improved endurance characteristics then conventional one was obtained.

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