• 한국시뮬레이션학회논문지
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• 제10권3호
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• pp.71-82
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• 2001

Considering material handling delay which occurs between storage and processing stations, we propose an algorithm to estimate the required storage capacity, i.e., number of aisles and number of openings in vertical and horizontal directions in each aisle, of an automated storage/retrieval(AS/R) system. Due to the random nature of storage and retrieval requests, proportion of single and dual commands is not known in advance. Two design criteria, maximum permissible overflow probability and maximum allowable storage/retrieval(S/R) machine utilization, are used to compute the storage capacity. Most of studies assume that storage capacity of AS/R systems is given, although it is a very important decision variable in the design phase. Therefore, the proposed model can be effectively used in the design phase of new AS/R systems.

• 대한산업공학회지
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• 제34권3호
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• pp.296-307
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• 2008

A semiconductor production system has sophisticated manufacturing operations and needs high capital investment for its expensive equipment, which warrants efficient real-time flow control for wafers. In the bay, we consider material handling equipment that can handle multiple carriers of wafers. The dispatching logic first determines the transportation time of each carrier to its destination by each unit of transportation equipment and uses this information to determine the destination machine and target carrier. When there is no available buffer space at the machine tool, the logic allows carriers to stay at the buffer of a machine tool and determine the delay time, which is used to determine the destination of carriers in URL. A simulation study shows this dispatching logic performs better than the procedure currently in use to reduce the mean flow time and average WIP of wafers and increase efficiency of material handling equipment.

• 한국위험물학회지
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• 제6권2호
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• pp.23-29
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• 2018

The fire and explosion properties necessary for waste, safe storage, transport, process design and operation of handling flammable substances are lower explosion limits(LEL), upper explosion limits(UEL), flash point, AIT( minimum autoignition temperature or spontaneous ignition temperature), fire point etc., An accurate knowledge of the combustion properties is important in developing appropriate prevention and control measures fire and explosion protection in chemical plants. In order to know the accuracy of data in MSDSs(material safety data sheets), the flash point of phenol was measured by Setaflash, Pensky-Martens, Tag, and Cleveland testers. And the AIT of phenol was measured by ASTM 659E apparatus. The explosion limits of phenol was investigated in the reference data. The flash point of phenol by using Setaflash and Pensky-Martens closed-cup testers were experimented at $75^{\circ}C$ and $81^{\circ}C$, respectively. The flash points of phenol by Tag and Cleveland open cup testers were experimented at $82^{\circ}C$ and $89^{\circ}C$, respectively. The AIT of phenol was experimented at $589^{\circ}C$. The LEL and UEL calculated by using Setaflash lower and upper flash point value were calculated as 1.36vol% and 8.67vol%, respectively. By using the relationship between the spontaneous ignition temperature and the ignition delay time proposed, it is possible to predict the ignition delay time at different temperatures in the handling process of phenol.

• 한국화재소방학회논문지
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• 제31권5호
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• pp.1-6
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• 2017

가연성물질의 화재 및 폭발 특성치는 안전한 취급, 저장, 수송, 처리 및 폐기하는데 반드시 필요하다. 공정 안전을 위한 대표적인 연소특성치로 최소자연발화온도(AIT)를 들 수 있다. 최소자연발화온도는 가연성 액체의 안전한 취급을 위해서 중요한 지표가 된다. 최소자연발화온도는 가연성물질이 주위의 열에 의해 스스로 발화하는 최저온도이다. 본 연구에서는 ASTM E659 장치를 이용하여 가연성 혼합물인 n-Pentanol과 p-Xylene 혼합물의 최소자연발화온도와 발화지연시간을 측정하였다. 2성분계를 구성하는 순수물질인 n-Pentanol과 p-Xylene의 최소자연발화온도는 각각 $285^{\circ}C$, $557^{\circ}C$로 측정되었다. 그리고 측정된 n-Pentanol과 p-Xylene 혼합물의 최소자연발화온도와 AIT에서의 발화지연시간의 실험값은 제시된 식에 의한 계산값과 적은 평균절대오차에서 일치하였다. 따라서 본 연구에서 제시한 예측식들을 이용하여 n-Pentanol과 p-Xylene 혼합물의 다른 조성에서도 최소자연발화온도와 발화지연시간을 예측이 가능하다.

• 한국안전학회지
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• 제33권4호
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• pp.8-14
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• 2018

In the industrial chemical process involving combustible materials, reliable safety data are required for design prevention, protection and mitigation measures. The accurate combustion properties are necessary to safely treatment, transportation and handling of flammable substances. The combustion parameters necessary for process safety are lower flash point, upper flash point, fire point, lower explosion limit(LEL), upper explosion limit(UEL)and autoignition temperature(AIT) etc.. However, the combustion properties suggested in the Material Safety Data Sheet (MSDS) are presented differently according to the literatures. In the chemical industries, tetralin which is widely used as a raw material of intermediate products, coating substances and rubber chemicals was selected. For safe handling of tetralin, the lower and flash point, the fire point, and the AIT were measured. The LEL and UEL of tetralin were calculated using the lower and upper flash point obtained in the experiment. The flash points of tetralin by using the Setaflash and Pensky-Martens closed-cup testers measured $70^{\circ}C$ and $76^{\circ}C$, respectively. The flash points of tetralin using the Tag and Cleveland open cup testers are measured $78^{\circ}C$ and $81^{\circ}C$, respectively. The AIT of the measured tetralin by the ASTM E659 apparatus was measured at $380^{\circ}C$. The LEL and UEL of tetralin measured by Setaflash closed-cup tester at $70^{\circ}C$ and $109^{\circ}C$ were calculated to be 1.02 vol% and 5.03 vol%, respectively. In this study, it was possible to predict the LEL and the UEL by using the lower and upper flash point of tetralin measured by Setasflash closed-cup tester. A new prediction method for the ignition delay time by the ignition temperature has been developed. It is possible to predict the ignition delay time at different ignition temperatures by the proposed model.

• 한국안전학회지
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• 제29권6호
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• pp.55-61
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• 2014

The autoignition temperature (AIT) of a material is the lowest temperature at which the substance will spontaneously ignite in the absence of an external ignition source such as a spark or flame. The AIT may be used as combustion property to specify operating, storage, and materials handling procedures for processs safety. This study measured the AITs of n-Propanol+n-Decane system from ignition delay time(time lag) by using ASTM E659 apparatus. The AITs of n-Propanol and n-Decane which constituted binary system were $435^{\circ}C$ and $212^{\circ}C$, respectively. The experimental AITs of n-Propanol+n-Decane system were a good agreement with the calculated AITs by the proposed equations with a few A.A.D(average absolute deviation).

• 한국해양공학회지
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• 제19권6호통권67호
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• pp.86-91
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• 2005

Regarding some of tire important works in tire shipyard, like tire production process, quality control, and material handling, there are many elements that disturb tire work-flaw. For example, there are mistakes in manufacturing, delay of production, and poor quality. These kinds of disturbances are from tire delay of communication time between tire production field and tire management. Therefore, it would be possible to strengthen tire competitiveness of shipbuilding industries by applying tire information technology based on Wireless Local Area Network (Wireless LAN), in order to establish tire multi-possession of real time production information in limited large shipbuilding yard. In this study, tire construction concept of tire information system, based on Wireless LAN, is proposed to build communication infrastructures in shipyards. The various information regarding shipbuilding inspection, process management, and material flaw are analyzed and constructed to databases in tire middle ware system, as tire platform for using Personal Display Agent (PDA). At last, tire middle ware system, which delivers tire information, is developed by tire C$\sharp$ and Microsoft.net; also, tire PDA application system is structured in WinCE O/S, and is tested and evaluated under tire server linked condition.

• 한국안전학회지
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• 제21권3호
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• pp.45-52
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• 2006

The AITs(autoignition temperatures) describe the minimum temperature to which a substance must be heated, without the application of a flame or spark, which will cause that substance to ignite. The AITs are often used as a factor in determining the upper temperature limit for processing operations and conditions for handling, storage and transportation, and in determining potential fire hazard from accidental contact with hot surfaces. The measurement AITs are dependent upon many factors, namely initial temperature, pressure, volume, fuel/air stoichiometry, catalyst material, concentration of vapor, time lag. Therefore, the AITs reported by different ignition conditions are sometimes significantly different. This study measured the AITs of benzene, toluene and xylene isomers from time lag using AS1M E659-78 apparatus. The experimental ignition delay times were a good agreement with the calculated ignition delay times by the proposed equations wtih a few A.A.D.(average absolute deviation). Also The experimental AITs of benzene, toluene, o-xylene, m-xylene and p-xylene were $583^{\circ}C,\;547^{\circ}C,\;480^{\circ}C,\;587^{\circ}C,\;and\;557^{\circ}C$, respectively.

• Korean Chemical Engineering Research
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• 제56권4호
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• pp.474-478
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• 2018

공정안전을 위해서는 산업현장에서 취급하는 가연성물질의 화재 및 폭발 특성치가 있어야 한다. 사업장에서 사고를 예방하기 위한 연소특성치로 인화점, 연소점, 전폭발한계, 최소자연발화온도 등을 들 수 있다. 그러나 물질보건안전자료(MSDS)에서 제시하고 있는 특성치는 문헌들에 따라 달리 제시되고 있는데, 가연성물질을 안전하게 처리, 수송, 취급하기 위해서는 정확한 연소특성치가 필요하다. 화학산업에서 중간제품, 고무약품 등의 원료로 다양하게 사용되고 있는 노말에틸아닐린을 선정하였다. 그리고 노말에틸아닐린 안전한 취급을 위해서 인화점, 연소점 그리고 최소자연발화온도를 측정하였다. 노말에틸아닐린의 폭발하한계는 실험에서 얻어진 하부인화점을 이용하여 계산하였다. 노말에틸아닐린의 Setaflash 밀폐식은 $77^{\circ}C$, Pensky-Martens 밀폐식에서는 $82^{\circ}C$ 그리고 Tag 개방식에서는 $85^{\circ}C$, Cleveland 개방식에서는 $92^{\circ}C$로 측정되었다. ASTM E659 장치에 의한 측정된 노말에틸아닐린의 최소자연발화온도는 $396^{\circ}C$로 측정되었다. Setaflash 밀폐식에 의해 측정된 노말에틸아닐린의 하부인화점 $77^{\circ}C$에 의한 폭발하한계는 1.02 vol%로 계산되었다. 본 연구에서는 밀폐식에 의해 측정된 노말에틸아닐린의 하부인화점을 이용하여 폭발하한계의 예측이 가능하였다. 본 연구에서 제시된 노말에틸아닐린의 발화온도와 발화지연시간의 관계식은 노말에틸아닐린의 다른 발화온도에서도 발화지연시간의 예측이 가능해졌다.

• 한국산업융합학회 논문집
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• 제12권1호
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• pp.19-25
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• 2009

We suggest and evaluate a dynamic scheduling rule of machines and material handling systems for on-line operation in job shop type Flexible Manufacturing System. Alternating status should be able to take operation scheduling procedures and without delay in dynamic industrial environments effectively. The interaction(SPT-NS, SPT-QSNS, SPT-NUJ, EDD-NS, EDD-QSNS, EDD-NUJ, CR-NS, CR-QSNS, CR-NUJ) between machine operation scheduling and AGV dispatching rule were also studied in this research. The performance evaluation which was obtained from DSS compares the performance of Flow time, and Empty to loaded travel ratio. It is Compared with the best rules & two system.