• Journal of the Korean Institute of Gas
• /
• v.19 no.3
• /
• pp.18-24
• /
• 2015

The flash point is one of the most important indicators of the flammabiliy of liquid solutions. The flash point is the lowest temperature at which there is enough concentration of flammable vapor to form an ignitable mixture with air. In this study the flash points of binary flammable solutions, 2-propanol+propionic acid and n-hexanol+formic acid systems, were measured using Seta flash closed cup tester. Particularly n-hexanol+formic acid system exhibited minimum flash point behavior. The measured values were compared with the calculated values using Raoult's law and optimization method. The calculated data by optimization method described the measured values more effectively than those calculated by Raoult's law.

• Journal of the Korean Society of Safety
• /
• v.31 no.4
• /
• pp.42-47
• /
• 2016

The combustible properties(flash point, explosion limit and autoignition temperature) are the important safety items which are considered in the typical MSDS(material safety data sheet). In this study, for the safe handling of n-butyl methacrylate(n-BMA) being used in various ways in the chemical industry, the flash point and the autoignition temperature(AIT) of n-butyl methacrylate was experimented. And, the lower explosion limit of n-butyl methacrylate was calculated by using the lower flash point obtained in the experiment. The flash points of n-butyl methacrylate by using the Setaflash and Pensky-Martens closed-cup testers measured $44^{\circ}C$ and $51^{\circ}C$, respectively. The flash points of n-butyl methacrylate by using the Tag and Cleveland open cup testers are measured $53^{\circ}C$. The AIT of n-butyl methacrylate by ASTM 659E tester was measured as $295^{\circ}C$. The lower explosion limit by the measured flash point $44^{\circ}C$ was calculated as 0.85 vol.%. It was possible to predict lower explosion limit by using the experimental flash point or flash point in the literature.

• Journal of Information Technology Applications and Management
• /
• v.11 no.1
• /
• pp.189-200
• /
• 2004

Recently Flash Memory which is small and low-powered is widely used as a storage of embedded system, because an embedded system requests portability and a fast response. To resolve a difference of access time between a storage and RAM, Linux is using disk caching which copies a part of file on disk into RAM. It is not also an exception on embedded system. A READ access-time of flash memory is similar to RAMs. So, when a process on an embedded system reads data, it is similar to the time to access cached data in RAM and to access directly data on a flash memory. On the embedded system using limited memory, using a disk cache is that wastes much time and memory spaces to manage it and can not reflects the characteristic of a flash memory. This paper proposes the regular file access of limited using a page cache in the file system based on a flash memory and reflects the characteristic of a flash memory. The proposed algorithm minimizes power consumption because access numbers of the RAM are reduced and doesn't waste a memory space because it accesses directly to a flash memory Therefore, the performance improvement of the system applying the proposed algorithm is expected.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• 2015.05a
• /
• pp.259-263
• /
• 2015

The vulnerabilities related to Flash player which is widely used in internet browsers and office programs are gradually increased. To detect Flash malwares, previous work focuses on predefined features of ActionScript. However above work cannot detect new/mutated Flash malwares, since predefined features could not cover the new patterns of new/mutated Flash mawares. To solve this problem, we propose a Flash malware detection method that uses machine learning to learn Flash Tag patterns and classify Flash by using machine learning.

• IEMEK Journal of Embedded Systems and Applications
• /
• v.13 no.5
• /
• pp.235-243
• /
• 2018

NAND flash memory has been widely used for embedded systems as storage device and the flash memory file systems such as JFFS2, YAFFS/YAFFS2 have been adopted by these embedded systems. The flash memory file systems provide the high performance and overcome the limitations of flash memory. However, these file systems don't solve the slow mount time problem when a sudden power failure happens. In this paper, we proposed a flash memory management method for enhancing the recovery performance. The proposed method manages the flash memory block type and stores the block type information at recovery image block. When file operations are occurred, our method stores the file information at the metadata block before and after the file operation. When mounting the flash memory, our method only scans the recovery image blocks and metadata blocks. The proposed method reduces the mount time by seeking the metadata block locations fast by using the recovery image blocks. We implemented the proposed method and evaluation results show that our method reduces the mount time 13 ~ 46 % compared with YAFFS2.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
• /
• v.9 no.1
• /
• pp.547-550
• /
• 2005

This treatise studies and developed flash memory drive of ATA bus that use flash memory which is employment amount memory semiconductor to improve problem of hard-disk that is existing ATA bus. While general hard-disk is sensitive external impact or shock, but flash memory drive do save chapter as well as is strong in external impact using semiconductor memory element that disk is not low electric power, light weight possible . Practical use is expected do save chapter for embedded system or black box for vehicles, soldiers hereafter therefore.

• Journal of KIISE:Computing Practices and Letters
• /
• v.11 no.4
• /
• pp.305-311
• /
• 2005

Flash memory software running on cellular phones and PDAs need to be tested extensively to cope with abrupt power and media faults. For those tests, we designed and implemented a Flash memory emulator with fault injection features. The fault injection tester has provided a helpful framework for designing fault recovery schemes and also for analyzing fault damages to the FTL (Flash Translation Layer) and file system for a Flash memory based system. In this paper, we discuss Plash memory fault types and fault injection features implemented on this Flash memory emulator. We then discuss in detail a design flaw revealed during fault injection tests. Specifically, it was revealed that a scheme that was believed to improve reliability instead, turned out to be harmful. In addition, we discuss post-fault behaviors of the FTL and the file system.

• Clean Technology
• /
• v.26 no.4
• /
• pp.279-285
• /
• 2020

Laboratories and industrial processes typically involve the use of flammable substances. An important property used to estimate fire and explosion risk for a flammable liquid is the flash point. In this study, flash point data at 101.3 kPa were determined using a SETA closed cup flash point tester on the following solvent mixtures: {2,2,4-trimethylpentane + methylcyclohexane}, {2,2,4-trimethylpentane + ethylbenzene}, and {2,2,4-trimethylpentane + p-xylene}. The purpose of this work is to obtain flash point data for binary mixtures of 2,2,4-trimethylpentane with three hydrocarbons (methylcyclohexane, ethylbenzene, and p-xylene), which are representative compounds of the main aromatic hydrocarbon fractions of petroleum. The measured flash points are compared with the predicted values calculated using the GE models' activity coefficient patterns: the Wilson, the Non-Random Two-Liquid (NRTL), and the UNIversal QUAsiChemical (UNIQUAC) models. The non-ideality of the mixture is also considered. The average absolute deviation between the predicted and measured lower flash point s is less than 1.99 K, except when Raoult's law is calculated. In addition, the minimum flash point behavior is not observed in any of the three binary systems. This work's predicted results can be applied to design safe petrochemical processes, such as identifying safe storage conditions for non-ideal solutions containing volatile components.

• Corrosion Science and Technology
• /
• v.22 no.5
• /
• pp.341-350
• /
• 2023

In the present study, effects of a thin Zn-flash coating on hydrogen evolution, infusion, and embrittlement of advanced high strength steel during electro-galvanizing were examined. The electrochemical permeation technique in conjunction with impedance spectroscopy was employed under applied cathodic polarization. Moreover, a slow-strain rate test was conducted to evaluate loss of elongation (i.e., indicative of hydrogen embrittlement (HE)) and examine fracture surfaces. Results showed that the presence of a thin Zn-flash coating, even when it was not distributed uniformly, reduced hydrogen evolution rate and substantially impeded infusion of hydrogen into the steel substrate. This was primarily due to a hydrogen overvoltage on Zn coating and trapping of hydrogen at the interface of Zn coating/flash coating/steel substrate. Consequently, the sample with flash coating had a smaller HE index than the sample without flash coating. These results suggest that a thin Zn-flash coating could be an effective technical strategy for mitigating HE in advanced high-strength steels.

• Journal of Korea Multimedia Society
• /
• v.11 no.5
• /
• pp.651-660
• /
• 2008

Flash memory is widely used in embedded systems because of its benefits such as non-volatile, shock resistant, and low power consumption. However, NAND flash memory suffers from out-place-update, limited erase cycles, and page based read/write operations. To solve these problems, YAFFS and RFFS, the flash memory file systems, are proposed. However YAFFS takes long time to mount the file system, because all the files are scattered all around flash memory. Thus YAFFS needs to fully scan the flash memory. To provide fast mounting, RFFS has been proposed. It stores all the block information, the addresses of block information and meta data to use them at mounting time. However additional operations for the meta data management are decreasing the performance of the system. This paper presents a new NAND flash file system called ERFFS (Efficient and Reliable Flash File System) which provides fast mounting and recovery with minimum mata data management. Based on the experimental results, ERFFS reduces the flash mount/recovery time and the file system overhead.