• 한국생산제조학회지
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• 제25권5호
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• pp.338-344
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• 2016

Recent trends in transport system for carrying heavy freight are that demands of a high efficiency, economic efficiency, convenience and safety are increased. Conventional transport systems were poor in transport efficiency and economic efficiency. And Safety problems can be caused to products and workers. In order to overcome these problems, an air cushion transport device with a high-pressure air is required. The air cushion transporter is a device for reducing the frictional force of floor surface and lifting the heavy freight by spraying the high-pressure air to the floor. Technology to float and transfer freight using high-pressure air is very convenient and initial cost can be reduced. In this paper, the study on the levitation performance and transport efficiency of air cushion transport system is conducted and verified that air cushion transporter has a significantly higher transport efficiency than conventional heavy handling systems.

• 동력기계공학회지
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• 제19권5호
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• pp.17-24
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• 2015

In this paper, the development of an air cushion transporter has been studied. To do this, theoretical analysis is introduced to design the equipment and computational fluid dynamics is also conducted. Design of an air cushion transporter for heavy load carriage is completed and a prototype is manufactured. Through the analysis and experiment of the developed the prototype, it can be known that the developed transporter can levitate the load of about 1 ton at the applied pressure of 0.2 MPa and the maximum lifting height at this condition is 17mm.

• 산업경영시스템학회지
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• 제46권4호
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• pp.160-172
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• 2023

In contemporary global warfare, the significance and imperative of air transportation have been steadily growing. The Republic of Korea Air Force currently operates only light and medium-sized military cargo planes, but does not have a heavy one. The current air transportation capability is limited to meet various present and future air transport needs due to lack of performance such as payload, range, cruise speed and altitude. The problem of population cliffs and lack of airplane parking space must also be addressed. These problems can be solved through the introduction of heavy cargo planes. Until now, most studies on the need of heavy cargo plane and increasing air transport capability have focused on the necessity. Some of them suggested specific quantity and model but have not provided scientific evidence. In this study, the appropriate ratio of heavy cargo plane suitable for the Korea's national power was calculated using principal component analysis and cluster analysis. In addition, an optimization model was established to maximize air transport capability considering realistic constraints. Finally we analyze the results of optimization model and compare two alternatives for force structure.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.81-82
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• 2006

Conveyor-type transporters have been widely used as a typical delivery system of semi-conductor, FPD and other IT-related products. However, as the IT-product is getting larger in size and higher in resolution, several problems are caused by mechanical contacts between the transporter and target object. In this context, recently, lots of efforts are being devoted for development of various contact-free handling systems to get rid of deffets and oil contaminations. The objectives of this paper are to characterize suspension mechanisms and to investigate air flow effects on air levitation transport system. For this purpose, a series of CFD analyses were carried out and the simulation data showed a good agreement with the corresponding experimental ones. It is anticipated that the promising result can be used as a basis for concept design of the transport system.

• 한국의류산업학회지
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• 제17권2호
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• pp.247-257
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• 2015

This study conducted a questionnaire survey on the real condition of clothing with focus on related to general motorcycle wear and motorcycle jacket targeting a quick service carrier affiliated with a quick service business in Seoul. In addition, this study is aimed at providing basic data on developing the motorcycle jacket, whose motional flexibility, safety and functionality are excellent, exclusively for a quick service carrier by grasping inconveniences and problems and deducting improvements on the basis of the questionnaire survey. This study, on the basis of the questionnaire survey results, grasped the general part related to quick service and motorcycle wear, such as their general matters, whether they were having on the motorcycle wear in the middle of doing business, whether it's necessary to wear the motorcycle wear, where they had a driving accident, and kinds of external injuries, etc. From the gathered results of analysis of the collected questionnaires, the item which got the lowest satisfaction was the inconvenience from the chafed front neck when driving. Besides, the results showed carriers' complaints like the elbow part felt tight, discomfort in the horizontal movement of the shoulders or back, and wind admission in between zippers. In addition, the respondents showed complaints in the item about hygroscopic property and air permeability at the armpits and back part, and 5 items about material flexibility, wind shielding property, living water repellency, weighty sensation, and night visibility were found to be low in respondents' satisfaction.

• Journal of Preventive Medicine and Public Health
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• 제37권4호
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• pp.329-336
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• 2004

Objectives : Iron (Fe) is an essential element in biological processes; however excessive Fe is harmful to human health. Some air pollutants contain a high level of Fe, and the human lung could therefore be over-exposed to Fe through inhaled air pollutants. This study was performed to investigate the role of metal transporters (divalent metal transporter 1, DMT1, and metal transporter protein 1, MTP1) in the lung under the environments of Fe deficiency in the body and Fe over-exposure in the lung. Methods : Rats were fed Fe deficient (FeD, 2-6 mg Fe/kg) or Fe supplemented (FeS, 120 mg Fe/kg) diet for 4 weeks, followed by a single intratracheal instillation of ferrous sulfate at low (10 mg/kg) or high (20 mg/kg) dose. Fe concentration was analyzed in the serum, lung and liver, and histopathological findings were observed in the lung at 24 hours after Fe administration. The level of DMT1 and MTP1 expression in the lung was analyzed by RT-PCR. Also, the effect of Fe deficiency in the body was evaluated on the level of Fe concentration and metal transporters compared to FeS-diet fed rats at the end of 4-week FeD or FeS diet. Results : The 4-week FeD diet in rats induced an Fe deficiency anemia with decreased serum total Fe, increased unsaturated Fe binding capacity and hypochromic microcytic red blood cells. The concentration of Fe in the lung and liver was lower in the FeD-diet fed rats than in the FeS-diet fed rats. The level of metal transporters mRNA expression was higher in the FeD-diet fed rats than in the FeS-diet. The concentration of Fe in the lung was increased in a dose-dependent pattern after intratracheal instillation of Fe into the rats, while the level of Fe in the serum and liver was not increased in the low-dose Fe administered rats. Therefore, DMT1 and MTP1 mRNA was highly expressed in both FeD-diet and FeS-diet fed rats, after intratracheal instillation of Fe. Conclusions : DMT1 and MTP1 mRNA were more highly expressed in FeD-diet fed rats than in FeS-diet fed rats. The over-exposure of Fe intratracheally induced high expression of metal transporters and increased Fe deposition in the lung in both FeD-diet and FeS-diet fed rats, but did not increase the Fe level of the serum and liver in low-dose Fe administered rats. These results suggest that the role of metal transporters in the lung might be different in a part from the duodenum under the environment of over-exposure to Fe.

• 항공우주정책ㆍ법학회지
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• 제20권2호
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• pp.9-58
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• 2005

국제항공운송에서 발생하는 민사적 손해배상책임을 통일적으로 규율하고, 미약한 발전단계에 있던 항공운송산업의 발전을 도모하기 위하여 1929년 제정된 '국제 항공 운송인의 책임에 관한 일부 규칙을 통일하기 위한 바르샤바 조약'은 국제항공운송에서 발생하는 민사적 손해배상책임에 대해 각 국의 국내법에 우선하여 배타적으로 적용된다. 즉, 바르샤바조약은 '국제항공운송에서 발생한 손해배상책임에 관한 소송은 그 명의의 여하를 불문하고 조약에 정하여진 조건과 제한 하에서만 제기할 수 있다'고 규정하고 있는 것이다 (제24조 제1항). 여기서 규정하고 있는 '제한'에는 국제항공운송에서 발생한 손해의 배상청구소송을 제기할 때에 있어서의 절차적 제한도 포함되는 것으로 보는 것이 일반적이며, 그러한 절차적 제한과 관련하여 바르샤바조약은 제29조에서 항공사고를 비롯한 국제항공운송에서의 인적, 물적 손해배상을 구하는 소송은 2년의 기한 내에 제기되어야 하고, 그 기한을 도과하여 제기된 소송에서는 손해배상을 구할 수 없도록 하는 절차적 제한규정을 두고 있다. 그러한 2년의 기간의 성격을 놓고 상이한 해석이 미국판례법상에 존재하고 있다. 제29조 제2항이 제l항에서 규정된 2년의 기간의 계산방법을 소송이 제기된 국가의 법률에 따르도록 규정하고 있는데 그 규정의 해석에 입장의 차이가 있는 바, 제2항의 규정을 어떻게 해석하느냐에 따라 2년의 기간이 연장(Tolling)될 수도 있는 것이다. 이와 관련하여 2년의 기간을 소송제기가 가능한 기간을 규정한 출소기한규정(statute of limitations)으로 보는 견해와 소송제기의 전제조건(condition precedent to the right to bring suit)으로 보는 견해가 있다.