• Title/Summary/Keyword: Physical Cause

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Transient Vibration Identification and Reduction of a Centrifugal Fan for a Wall-installed Air-conditioner (벽걸이에어컨의 원심홴에 대한 과도진동 규명 및 저감)

  • Kim, Minsung;Lim, Jonghyuk;Chung, Jintai
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.26 no.4
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    • pp.383-390
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    • 2016
  • In this paper, experiment and dynamics simulations were carried out to identify and reduce the out-of-plane vibration that occurs in a centrifugal fan of an air conditioner installed to a wall. In a wall-installed air conditioner, large space between a case and heat exchanger is often required for the fan to avoid the collision with the case and exchanger. This large space hinders the slim design of the air conditioner even if air conditioner market demands a slim air conditioner. In the present study, in order to determine the cause of the vibration in the centrifugal fan, the out-of-plane vibration and the physical properties were investigated, and the dynamic characteristics of the centrifugal fan were obtained by experiments. Based on these experiments, a dynamic simulation model was established to determine the cause of the out-of-plane vibration of the centrifugal fan. It was found that the main factor of out-of-plane vibration in the centrifugal fan is the axial misalignment between the centrifugal fan and the motor shaft.

Development of Korean Stress Model for the Unmarried Workers in Korea (한국에서 미혼 근로자를 위한 한국형 스트레스 모형 개발)

  • Gang, Yeong-Sik;Yang, Seong-Hwan;An, Gwang-Hyeok;Jeong, Yu-Na;Lee, Seul;Nam, Geon-U;Park, Min-A;Gwon, Yong-O;Lee, Won-Gi;Kim, Seong-Hyeon;Park, Seon-Yeong
    • Proceedings of the Safety Management and Science Conference
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    • 2012.04a
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    • pp.35-41
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    • 2012
  • The unsafe act and unsafe condition is induced by the fundamental cause factors of industrial accidents. In this paper, stress is classified into job, life and workplace stress. Therefore, the purpose of this paper is to develop a Korean stress model focused on the unmarried workers in order to prevent fundamental industrial accidents. The results of this paper are followed. First, the oriental culture and idea in Korea is directly connected to the central axis of all life. Accordingly, concrete and systematic safety management methods should be proposed from the point of Korean culture. Finally, the industrial accident questionnaire needs an item that reports the mental and physical condition of workers in order to prevent occupational diseases.

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Apparent life-threatening event in infancy

  • Choi, Hee Joung;Kim, Yeo Hyang
    • Clinical and Experimental Pediatrics
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    • v.59 no.9
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    • pp.347-354
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    • 2016
  • An apparent life-threatening event (ALTE) is defined as the combination of clinical presentations such as apnea, marked change in skin and muscle tone, gagging, or choking. It is a frightening event, and it predominantly occurs during infancy at a mean age of 1-3 months. The causes of ALTE are categorized into problems that are: gastrointestinal (50%), neurological (30%), respiratory (20%), cardiovascular (5%), metabolic and endocrine (2%-5%), or others such as child abuse. Up to 50% of ALTEs are idiopathic, where the cause cannot be diagnosed. Infants with an ALTE are often asymptomatic at hospital and there is no standard workup protocol for ALTE. Therefore, a detailed initial history and physical examination are important to determine the extent of the medical evaluation and treatment. Regardless of the cause of an ALTE, all infants with an ALTE should require hospitalization and continuous cardiorespiratory monitoring and evaluation for at least 24 hours. The natural course of ALTEs has seemed benign, and the outcome is generally associated with the affected infants' underlying disease. In conclusion, systemic diagnostic evaluation and adequate treatment increases the survival and quality of life for most affected infants.

Foot and ankle pain in soccer players (축구 선수에서의 발목 및 발의 통증)

  • Lee Kyung-Tai;Young Ki-Won;Kim Jae-Young;Cha Seung-Do;Kim Eung-Soo
    • Journal of Korean Orthopaedic Sports Medicine
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    • v.3 no.1
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    • pp.36-41
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    • 2004
  • The purpose of this study is to describe the common injuries in soccer players in terms of the orthopaedic operative treatment. We classified foot pain to in forefoot , midfoot, plantar aspect and mentioned the cause, incidence and treatment methods. Ankle pain was classified to anterior, lateral, medial and posterir aspect of the ankle. In all injuries in soccer players, conservative treatment is primary treatment method and we treated operatively in no respond case inspite of the physical therapy and rehabilitation program for sufficient period. The anatomical repair was preferred and minimal invasive surgery was recommended if possible and then focus of treatment is to early return to previous full activities through the rehabilitation program for sufficient period. As a conclusion, it is necessory to understand the mechanism and cause of the common injuries in soccer players and to select the proper treatment method to the degree of the injuries.

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Differential diagnosis of vertigo (어지럼증의 감별진단)

  • Kang, Ji-Hoon;Shin, Ji-Yong;Kim, Min-Ju;Ma, Hyeo-Il
    • Journal of Medicine and Life Science
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    • v.16 no.3
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    • pp.64-75
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    • 2019
  • Vertigo and dizziness are common symptoms with various etiologies and pathogeneses. Vertigo is an illusion of motion due to disease of the vestibular system, usually a sense of rotation. Dizziness, a term that represents a wide range of non-vertigo symptoms, is commonly associated with non-vestibular disorders including old age, cardiac syncope, orthostatic hypotension, metabolic disease, anxiety, and drugs. Vertigo should be determined whether the cause is central or peripheral. Peripheral vertigo is usually benign but central vertigo is serious and often require urgent treatment. The careful history and detailed physical examinations(pattern of nystagmus, ocular tilt reaction, head impulse test and positional tests such as Dix-Hallpike maneuver) provide important clues to the diagnosis of vertigo. Most of patients have benign peripheral vestibular disorders - vestibular neuritis, benign paroxysmal positional vertigo (BPPV), and Meniere's disease. BPPV is a leading cause of peripheral vertigo and can easily be cured with a canalith repositioning maneuver. In this review, a focus is on the differential diagnosis of common vestibular disorders with peripheral and central causes.

Influence of Adjacent Structures on Surface-Wave Dispersion Characteristics and 2-D Resistivity Structure (표면파 분산특성과 전기비저항 분포특성에 대한 인접구조물의 영향)

  • Joh, Sung-Ho;Kim, Bong-Chan;Cho, Mi-Ra;Kim, Suhk-Chol;Youn, Dae-Hee;Hong, Jae-Ho
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.10a
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    • pp.1318-1327
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    • 2008
  • Geotechnical sites in urban areas may have embedded structures such as utility lines and underground concrete structures, which cause difficulties in site investigation. This study is a preliminary research to establish knowledge base for developing an optimal technique for site investigation in urban areas. Surface-wave method and resistivity survey, which are frequently adopted for non-destructive site-investigation for geotechnical sites, were investigated to characterize effects of adjacent structures. In case of surface wave method, patterns of wave propagation were investigated for typical sets of multi-layered geotechnical profiles by numerical simulation based on forward modeling theory and field experiments for small-size model tests and real-scale tests in the field. In case of resistivity survey, 3-D finite element analyses and field tests were performed to investigate effects of adjacent concrete structures. These theoretical and experimental researches for surface-wave method and resistivity survey resulted in establishing physical criteria to cause interference of adjacent structures in site investigation at urban areas.

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The Health Effects of Whole Body Vibration

  • Lee, Soo-Jin;Roh, Soo-Yong
    • Journal of the Ergonomics Society of Korea
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    • v.32 no.4
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    • pp.297-301
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    • 2013
  • Objective: The purpose of this study is to review the hazards of whole body vibration(WBV) and prevent human injuries due to WBV. Background: Vibrations that shake the whole body in vehicles and vessels is WBV. Vibration at a specific frequency, and intensity in the human body can act as a hazard. But, it has not yet done enough research about effects of WBV. Method: We analyzed and reviewed occupational or ergonomic papers published past 30 years. Results: Exposure to whole body vibration can cause permanent physical injury or damage of the nervous system. In addition, it may cause problem in the cardiovascular system, digestive system, musculoskeletal system, endocrine system, reproductive system, and psychological system. The effect of vibration depends on its acceleration, duration, frequency, and direction. Conclusion: WBV-exposed human body experience a high risk of some illnesses such as lumbar spinal disorders. Some workers(bus drivers, truck drivers and heavy equipment operators) are the high risk population exposed to WBV. Application: The results of this study might help to judge and prevent occupational disease caused by WBV.

A Study on the Repair Method and the Damage Status of Wooden Architectural Heritages - Focused on the wooden architectural heritages in Jecheon - (목조 건축문화재의 훼손현황과 보수방안 연구 - 제천시 목조 건축문화재를 중심으로 -)

  • Lee, Wan-Geon
    • Korean Institute of Interior Design Journal
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    • v.25 no.3
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    • pp.82-89
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    • 2016
  • This study investigated the preservation status of wooden architectural heritages, designated as Chungcheongbuk-do designated heritage in Jecheon. The purpose of this paper is to find the damage cause and the preservation method of wooden architectural heritages. It was conducted using the research methods of the existing literature and field survey to compare a current status of wooden architectural heritages. The result are as followings. Firstly, it was found the problems of a break, a damage, etc. in the platform and the problems of a cracking, an exfoliation, a corrosion, a warp, etc. in the wall. And, it was found a cracking of the beam(梁) and a roof tile(瓦), a falling of Angto(仰土), a sagging roof, etc. in the roof. Secondly, the damage causes of wooden architectural heritages were mostly caused by the physical limitations of the materials. And, it was caused by a rainwater, a subsidence of ground settlement, a destruction of waterproof membrane, etc. Lastly, the repair methods are making a quicklime layer in the soil mound on a cracking and an exfoliation part, a resin treatment or strut operation on a corrosion part of column, etc.

Clinical and Pathological Aspects of Filarial Lymphedema and Its Management

  • Shenoy, R.K.
    • Parasites, Hosts and Diseases
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    • v.46 no.3
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    • pp.119-125
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    • 2008
  • Lymphatic filariasis, transmitted by mosquitoes is the commonest cause of lymphedema in endemic countries. Among 120 million infected people in 83 countries, up to 16 million have lymphedema. Microfilariae ingested by mosquitoes grow into infective larvae. These larvae entering humans after infected mosquito bites grow in the lymphatics to adult worms that cause damage to lymphatics resulting in dilatation of lymph vessels. This earliest pathology is demonstrated in adults as well as in children, by ultrasonography, lymphoscintigraphy and histopathology studies. Once established, this damage was thought to be irreversible. This lymphatic damage predisposes to bacterial infection that causes recurrent acute attacks of dermato-lymphangio-adenitis in the affected limbs. Bacteria, mainly streptococci gain entry into the lymphatics through 'entry lesions' in skin, like interdigital fungal infections, injuries, eczema or similar causes that disrupt integrity of skin. Attacks of dermato-lymphangio-adenitis aggravates lymphatic damage causing lymphedema, which gets worse with repeated acute attacks. Elephantiasis is a late manifestation of lymphatic filariasis, which apart from limbs may involve genitalia or breasts. Lymphedema management includes use of antifilarial drugs in early stages, treatment and prevention of acute attacks through 'limb-hygiene', antibiotics and antifungals where indicated, and physical measures to reduce the swelling. In selected cases surgery is helpful.

Carpal Tunnel Syndrome with Recurrent Motor Branch Entrapment: A Case Report (수근관 증후군에 동반된 운동 반회 신경 가지의 포착: 증례보고)

  • Kwon, Young Woo;Choi, In Cheul;Kwon, Hee-Kyu;Park, Jong Woong
    • Archives of Hand and Microsurgery
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    • v.23 no.4
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    • pp.267-270
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    • 2018
  • Recurrent motor branch entrapment syndrome is a compressive mononeuropathy of recurrent motor branch of median nerve. It is a rare condition as a cause of thenar muscle wasting and may have different pathogenesis. If such an anatomical variation is the cause, there is a possibility that thenar muscle atrophy remains if only the transcarpal ligament release is performed. We report a 25-year-old male patient with carpal tunnel syndrome with thenar muscle wasting 1 month ago.