• Title/Summary/Keyword: Central fatigue

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A Study on the Damage Design of Military Aircraft Structure Material by Armor Piercing Bullet Hit (철갑탄 피격에 의한 군용 항공기 구조재료의 손상설계에 관한 연구)

  • Hur, Jang-Wook;Hyun, Young-Jin
    • Journal of the Korea Institute of Military Science and Technology
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    • v.13 no.6
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    • pp.1051-1057
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    • 2010
  • Database for the damage reference by armor piercing bullet test was established for both tube and plate specimens having a range of thickness. As the inclined angles of hit are increasing, it has been found that penetration damage diameter tends to increases accordingly in both specimen of the tube and plate, and such penetration damage diameter on the rear side becomes bigger than those on the front side. The tube specimen showed that the damage becomes bigger when central areas rather than the peripheral were hit. Through the plate test, it also has been found that the penetration ballistic limit for Al alloy is about 25.4mm and that of stainless steel about 12.7mm. From the fatigue analysis results using the database for damage reference, it has been identified whether the safety requirements of military aircraft could be met.

Surgical Correction of Discrete Membranous Suaorti Stenosis (선천성 대동맥판막하 막상협착증 치험 2례)

  • 송인기
    • Journal of Chest Surgery
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    • v.23 no.3
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    • pp.532-536
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    • 1990
  • We experienced surgical correction of 2 cases of discrete membranous subaortic stenosis. Case 1 was 19 years old male patient. His complaints were fatigue, exertional dyspnea, syncope and angina for 8 years. Ejection. systolic murmur was heard at the second right intercostal space and diastolic murmur was heard at the apex. A thrill was palpated over the second right intercostal space and area of the carotid artery. 2-D echo, cardiac cath and left ventriculogram revealed discrete membranous subaortic stenosis and VSD. Complete excision of discrete membrane without mymectomy was done. VSD was closed with dacron patch and aortic valve was replaced with St. Jude medical valve. Case 11 was 16 years old female whose complaints were exertional dyspnea and syncope. Ejection systolic murmur was heard at second right intercostal space, but diastolic murmur was not heard. A thrill was palpated over the second right intercostal space and the area of carotid artery. 2-D echo, cardiac cath and left ventriculogram revealed discrete membranous subaortic stenosis. Complete excision of fibrous tissue and myotomy were made and aortic valve was replaced with St. Jude medical valve. Operative finding was followed: both aortic valves showed deformity of leaflets. Subaortic region had a thickened central fibrous body from which the ridge protruded. Both patient`s postoperative course were uneventful and short-term follow-up results were good except soft systolic murmur at the aortic area.

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Development of the Phased Array Ultrasonic Testing Technique for Nuclear Power Plant's Small Bore Piping Socket Weld (원전 소구경 배관 소켓용접부 위상배열 초음파검사 기술 개발)

  • Yoon, Byung-Sik;Kim, Yong-Sik;Lee, Jeong-Seok
    • Journal of the Korean Society for Nondestructive Testing
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    • v.33 no.4
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    • pp.368-375
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    • 2013
  • Failure of small bore piping welds is a recurring problem at nuclear power plants. And the socket weld cracking in small bore piping has caused unplanned plant shutdowns for repair and high economic impact on the plants. Consequently, early crack detection, including the detection of manufacturing defects, is of the utmost importance. Until now, the surface inspection methods has been applied according to ASME Section XI requirements. But the ultrasonic inspection as a volumetric method is also applying to enforce the inspection requirement. However, the conventional manual ultrasonic inspection techniques are used to detect service induced fatigue cracks. And there was uncertainty on manual ultrasonic inspection because of limited access to the welds and difficulties with contact between the ultrasonic probe and the OD(outer diameter) surface of small bore piping. In this study, phased array ultrasonic inspection technique is applied to increase inspection speed and reliability. To achieve this object, the 3.5 MHz phased array ultrasonic transducer are designed and fabricated. The manually encoded scanner was also developed to enhance contact conditions and maintain constant signal quality. Additionally inspection system is configured and inspection procedure is developed.

Management of Non-pain Symptoms in Terminally Ill Cancer Patients: Based on National Comprehensive Cancer Network Guidelines (말기암환자에서 통증 외 증상의 관리: 최신 NCCN(National Comprehensive Cancer Netweork) 권고안을 중심으로)

  • Lee, Hye Ran
    • Journal of Hospice and Palliative Care
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    • v.16 no.4
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    • pp.205-215
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    • 2013
  • Most terminally ill cancer patients experience various physical and psychological symptoms during their illness. In addition to pain, they commonly suffer from fatigue, anorexia-cachexia syndrome, nausea, vomiting and dyspnea. In this paper, I reviewed some of the common non-pain symptoms in terminally ill cancer patients, based on the National Comprehensive Cancer Network (NCCN) guidelines to better understand and treat cancer patients. Cancer-related fatigue (CRF) is a common symptom in terminally ill cancer patients. There are reversible causes of fatigue, which include anemia, sleep disturbance, malnutrition, pain, depression and anxiety, medical comorbidities, hyperthyroidism and hypogonadism. Energy conservation and education are recommended as central management for CRF. Corticosteroid and psychostimulants can be used as well. The anorexia and cachexia syndrome has reversible causes and should be managed. It includes stomatitis, constipation and uncontrolled severe symptoms such as pain or dyspnea, delirium, nausea/vomiting, depression and gastroparesis. To manage the syndrome, it is important to provide emotional support and inform the patient and family of the natural history of the disease. Megesteol acetate, dronabinol and corticosteroid can be helpful. Nausea and vomiting will occur by potentially reversible causes including drug consumption, uremia, infection, anxiety, constipation, gastric irritation and proximal gastrointestinal obstruction. Metoclopramide, haloperidol, olanzapine and ondansetron can be used to manage nausea and vomiting. Dyspnea is common even in terminally ill cancer patients without lung disease. Opioids are effective for symptomatic management of dyspnea. To improve the quality of life for terminally ill cancer patients, we should try to ameliorate these symptoms by paying more attention to patients and understanding of management principles.

Semisubmersible platforms with Steel Catenary Risers for Western Australia and Gulf of Mexico

  • Zou, Jun
    • Ocean Systems Engineering
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    • v.2 no.2
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    • pp.99-113
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    • 2012
  • Steel Catenary Risers (SCR) are the simplest and often the most economic solution compared to other riser types such as flexible pipe, riser towers, top tensioned risers, etc. The top of a SCR is connected to the host platform riser porch. The other end of the SCR connects to flowlines from subsea wells. The riser touchdown point (TDP), which is the location along the riser where contact with the sea floor first occurs, exhibits complex behaviors and often results in compression and fatigue related issues. Heave dynamic responses of semisubmersibles in extreme and operating sea states are crucial for feasibility of SCR application. Recent full field measurement results of a deep draft semisubmersible in Hurricane Gustav displayed the considerable discrepancies in heave responses characteristics between the measured and the simulated results. The adequacy and accuracy of the simulated results from recognized commercial software should be examined. This finding raised the awareness of shortcomings of current commercial software and potential risk in mega investment loss and environmental pollutions due to SCR failures. One main objective of this paper is to attempt to assess the importance and necessity of accounting for viscous effects during design and analysis by employing indicator of viscous parameter. Since viscous effects increase with nearly third power of significant wave height, thus newly increased metocean criteria per API in central Gulf of Mexico (GoM) and even more severe environmental conditions in Western Australia (WA) call for fundamental enhancements of the existing analysis tools to ensure reliable and robust design. Furthermore, another aim of this paper is to address the impacts of metocean criteria and design philosophy on semisubmersible hull sizing in WA and GoM.

The Effects of Muscle Contraction by Electrical Stimulation to V Wave and Median Frequency (전기자극에 의한 근 수축이 V wave와 중앙주파수에 미치는 영향)

  • Mun, Dal-Ju;Jeong, Dae-In;Lee, Jung-Woo;Jeong, Jin-Gyu;Kim, Tae-Youl;Oh, Myung-Hwa
    • Journal of the Korean Academy of Clinical Electrophysiology
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    • v.4 no.1
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    • pp.27-38
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    • 2006
  • This study analyzed changes in action potential of supraspinal neuron and motor unit depending on maximum tolerance isometric contraction(MTIC) by electrical stimulation and examined influence of functional electrical stimulation (FES) on spinal neuron adaptation. It selected 40 university students in their twenties and divided into experimental groups of 25% MTIC(I), 50% MTIC I (II), 75% MTIC(III) and 100% MTIC(IV) depending on MTIC by electrical stimulation, and performed isometric contraction of plantar flexor muscle to each experimental group with given contraction for 20 times. It measured V/Mmax and MDF pre and post exercise, compared volume of contraction. 1. V/Mmax ratio showed no significant difference in comparison among experimental groups. 2. There was significant difference in median frequency of gastrocnemius and soleus in action potential motor unit according to comparison among experimental groups(p<.001). When contraction by electrical stimulation was maximum, change was greatest. This results suggest that muscle contraction by electrical stimulation was influence to action potential of spinal motor neuron system which appear optimal level though aspect and difference degree were not in accordance. Consequently, optimal stimulation level of MTIC(50%) by FES would be lead to central nerve adaptation. muscle contraction by electrical stimulation was influence highly to MDF which should be consider to fatigue of motor unit for muscle contraction by electrical stimulation.

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A Case of Adrenoleukodystrophy Diagnosed as Hyponatremic Dehydration (저나트륨혈증성 탈수증으로 진단된 소아 부신백질이영양증 1례)

  • Lee, Sang Heon;Kim, HyungJin;Kwon, Young-Se;Kim, Soon-Ki;Lee, Ji-Eun
    • Journal of The Korean Society of Inherited Metabolic disease
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    • v.14 no.1
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    • pp.66-70
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    • 2014
  • X-linked adrenoleukodystrophy (ALD) is a uncommon metabolic disorder which derived by peroxismal ${\beta}$-oxidation and elevation of serum very long chain fatty acid (VLCFA). VLCFA is mainly accumulated in the myelin of the central nervous system and adrenal cortex, by which the expressed symptoms of this disease are mainly neurologic and endocrinologic (such as adrenal insufficiency). The mutations in the ABCD1 gene causes X-linked ALD, nevertheless its phenotypes and genotypes are poorly coordinated. We report the case of a 12-year-old boy with X-linked ALD who developed vomiting, fatigue and poor oral intake. Severe dehydration and hyponatremia were found in initial physical examination and laboratory test, but his motor/sensory nerve function and mental status were completely normal. We diagnosed ALD with diffuse high-intensity signal in both parietotemporal cerebellar white matter in brain MRI and elevated serum VLCFA. Later, we confirmed a novel c.1635-1G>A (IVS6-1G>A) mutations of the ABCD1 gene. With the discrepancy between its phenotypes and genotypes, various phenotypes could be seen in X-ALD patient. Careful examination and further studies for these patients will be needed.

Validation of Computational Fluid Dynamics Calculation Using Rossendorf Coolant Mixing Model Flow Measurements in Primary Loop of Coolant in a Pressurized Water Reactor Model

  • Farkas, Istvan;Hutli, Ezddin;Farkas, Tatiana;Takacs, Antal;Guba, Attila;Toth, Ivan
    • Nuclear Engineering and Technology
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    • v.48 no.4
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    • pp.941-951
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    • 2016
  • The aim of this work is to simulate the thermohydraulic consequences of a main steam line break and to compare the obtained results with Rossendorf Coolant Mixing Model (ROCOM) 1.1 experimental results. The objective is to utilize data from steady-state mixing experiments and computational fluid dynamics (CFD) calculations to determine the flow distribution and the effect of thermal mixing phenomena in the primary loops for the improvement of normal operation conditions and structural integrity assessment of pressurized water reactors. The numerical model of ROCOM was developed using the FLUENT code. The positions of the inlet and outlet boundary conditions and the distribution of detailed velocity/turbulence parameters were determined by preliminary calculations. The temperature fields of transient calculation were averaged in time and compared with time-averaged experimental data. The perforated barrel under the core inlet homogenizes the flow, and therefore, a uniform temperature distribution is formed in the pressure vessel bottom. The calculated and measured values of lowest temperature were equal. The inlet temperature is an essential parameter for safety assessment. The calculation predicts precisely the experimental results at the core inlet central region. CFD results showed a good agreement (both qualitatively and quantitatively) with experimental results.

Self-Help Education as Outreach Program for Osteoarthritis Patients in Rural Korea

  • Lee, Kyung-Sook;So, Ae-Young;De Gagne, Jennie C.;Choi, Jung-Sook;Lee, Eun-Hee;Suh, Gil-Hee;Choi, Sun-Ha;Heitkemper, Margaret M.
    • Journal of muscle and joint health
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    • v.18 no.2
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    • pp.270-281
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    • 2011
  • Purpose: This study was done to determine if osteoarthritis (OA) patients living in rural Korea would have a benefit from a structured group program focused on self-help strategies. Methods: A hundred and twenty-six patients with OA were recruited from nine Primary Health Care Posts. The experimental group received a 6-week self-help education program while the control group received usual care. T-tests and c2-tests were used to determine the homogeneity between the experimental and control groups. Independent sample t-tests were performed to determine the effect of the treatment program. To guard against such likelihood, the level of significance of t-test was determined by Bonferroni correction within the study constructs. When significant group differences were found in study variables at baseline, analysis of covariances (ANCOVAs) were used for group comparisons of outcome variables. Results: The experimental group reported more significant improvement in fatigue, difficulty with physical activity, depression, quality of life, self-efficacy, and health behaviors than did the control group. The experimental group also showed improvements in range of motion and muscle strength as compared to the control group. Conclusion: A self-help group education program was an effective and powerful strategy to promote physical and psychosocial health in OA patients

The Role of Dopaminergic Fibers on the Action of Psychotropic Drugs in 6-OHDA-treated Rats (6-OHDA 파괴 후 수종의 향정신약물의 작용에 대한 중추도파민 신경계의 역할)

  • 이순철;유관희
    • Journal of Ginseng Research
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    • v.17 no.3
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    • pp.187-195
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    • 1993
  • We have examined the functional role of central dopaminergic processes on the behavioral pharmacological effects induced by psychotropics and red ginseng saponins of normal rats and compared with that of brain damaged rats. Desipramine and clomipramine produced, a significant depression of the locomotor activity in normal rats, but in brain damaged rats, they did not have any effect throughout the experimental period of 4 hours. Total saponin (50~200 mg/kg), PT (25~50 mg/kg), PD (25~50 mg/kg), $Rg_1$(12.5~25 mg/kg), $Rb_1$ (12.5~50 mg/kg) did not change, and high concentrations of PT (100 mg/kg), PD (100 mg/kg) and $Rg_1$ (50 mg/kg) showed a significant decrease in the locomotor activity of one hour after administration but total saponin (100 mg/kg), PD (25~50 mg/kg), Rgl (12.5 mg/kg), $Rb_1$ (12.5 mg/kg) markedly increased the locomotor activity of four hour after administration in normal rats. On the other hand, total saponin (50 mg/kg), PT (100 mg/kg) and PD (100 mg/kg) Produced a prominent stimulation of the locomotor activity in brain damaged rats. These results suggest that the inhibition of the locomotor activity induced by antidepressants was not affected by the sensitivity of cerebral DA system, whereas red ginseng saponin showed antifatigue effect and also the stimulation of the locomotor activity induced by red ginseng saponin was mediated by the inhibition of cerebral DA system. These psychotropic action of red ginseng saponins could be responsible for the beneficial effects on conditions of fatigue and decreased alertness.

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