• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.233-236
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• 2009

In this study, the characteristic of the hybrid rocket motor with $LN_2O$(Liquid Nitrous oxide) was investigated experimentally. HDPE(High Density PolyEthlene) was used as fuel with different sized single port. When used $LN_2O$, combustion efficiency is lower than using $GN_2O$(Gas Nitrous oxide), because of completeness of vaporization of droplet and mixing. And regression rate was changed by different oxidizer phase. This behavior was considered that flame temperature and combustion of solid fuel front/end surface.

• Journal of Convergence for Information Technology
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• v.7 no.4
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• pp.91-96
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• 2017

In this paper, we aim to respond efficiently to crime by using Arduino and smartphone apps in response to increasing number of house-breaking crimes. It receives the signal of the sensor installed in the house and connects it with the app of the smartphone. To use the app, you can download the app from the user's smartphone, launch the app, and operate the operation outside the home, not only inside the house, by linking the executed app. Among the sensors installed in the house, the movement detection sensor is used to enhance the security, and the gas leakage sensor and the flame detection sensor can be used to easily detect the risk of fire and to prevent the fire early. Security is further enhanced by the ability to remotely control the front door with a smartphone. After that, various sensors can be added and it can be developed as a WiFi module in addition to the Bluetooth module.

• FOCUS: LIFE SCIENCE
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• no.1
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• pp.2.1-2.6
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• 2024

This article provides detailed instructions for the correct installation, maintenance, and troubleshooting of capillary gas chromatography (GC) columns. It emphasizes the importance of proper installation to ensure optimal performance and longevity of the column. The document covers various aspects such as column trimming, installation, conditioning, testing, storage, and ferrule selection. The installation process involves ensuring that the heated zones of the GC are cool before placing the column cage in the column oven. It is essential to avoid sharp bends or stress on the capillary column during installation and to connect the front end of the column into the GC inlet at the recommended insertion distance. The document also provides guidance on trimming the column, including the use of a ceramic wafer or capillary column cutter to achieve a clean, burr-free cut. For previously used columns, it recommends removing any capillary caps, positioning the nut and ferrule, and trimming 1-2 cm from the column. After installation, the column should be purged with carrier gas to remove any oxygen and avoid oxidizing the column. Conditioning the column involves ramping to the upper isothermal temperature limit and maintaining this temperature for a specified duration. It is crucial to maintain carrier gas flow during conditioning and not exceed the upper temperature limit of the column to avoid phase damage. The document also discusses testing column performance using a suitable method and performing a test injection to assess performance. It provides recommendations for column storage, including flame-sealing the capillary ends or using retention gaps for long-term storage. Additionally, it emphasizes the importance of routine maintenance and replacement of GC consumables to extend the column's lifetime. Ferrule selection is another important aspect covered in the article, with a variety of ferrule materials available for different applications. The characteristics of common ferrule options are presented in a table, including temperature limits, reusability, and suitability for specific detector types.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.1
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• pp.103-110
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• 2012

The flow field, fuel-air mixing, and behaviors of turbulent flames have been investigated using the large eddy simulation (LES) numerical technique in a premixed swirl combustor equipped with EV double cone burners. Recirculation zones are generated by the swirl burner, and lean premixed flames are formed within a distance of 0.2 m from the tip of the burner. NOx emission of 0.46 ppm is predicted at 1 atm and an air/fuel ratio of 38.7. However, most of the CO generated in a flame front continues to be oxidized as it moves toward the exit, and CO emission of 5.45 ppm is predicted at the exit. The NOx emission can be reduced by decreasing the pressure and air/fuel ratio. The characteristics of NOx emission have been investigated through RANS simulations for various fuel injection types, and it is found thereby that five-lance-hole injection produces the lowest NOx emission rate.

• Journal of Environmental Science International
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• v.16 no.3
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• pp.385-392
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• 2007

Currently, portable equipment for recycling of waste asphalt concrete (ASCON) has been used. However, any air pollution control devices are not attached in the simple portable one. Thus, a lot of air pollutants have been produced from recycling processes of waste ASCON which resulted from aging of paved roads or repavement of roads. This study deals with a preliminary result of concentration analysis of air pollutants obtained from a pilot and a real recycling processes of waste ASCON using simple portable recycling equipment. Air pollutants were taken from 4 steps of the pilot recycling process including an initial heating by liquid petroleum gas (LPG), intermediate heating and melting (H&M) process, final H&M process, and pavement processes using recycled ASCON at the recycling site. Also, air pollutants were taken front 4 steps of the real recycling processes including an initial H&M, final H&M and mixing, loading of recycled ASCON to dump trucks, and at the recycling site after leaving the loaded dump trucks for real pavement sites. The air pollutants measured in this study include volatile organic compounds (VOCs), aldehydes, particulate matter (PM: PM1, PM2.5, PM7, PM10, TSP (total suspended particulate)). The identified concentrations of VOCs increased with increasing time or degree for H&M of waste ASCON. In particular, very high concentrations of the VOCs at the status of complete melting, which is exposed to the air, of the waste ASCON just before paving tv the recycled ASCON at the recycling site. Also, considerable amount of VOCs were identified from the recycling equipment after the dump trucks leaded by recycled ASCON leaved the recycling site for the pavement sites. The relative level of formaldehyde exceeded 80% of the aldehydes Identified in the recycling processes. This is because the waste ASCON is exposed to direct flame of LPG during H&M processes. The PM concentrations measured in the winter recycling processes, such as the loading and rotation processes of waste ASCON into/in the recycling equipment for H&M, were much higher than those in the summer ones. In particular, the concentrations of coarse particles such as PM7 and PM10 during the winter recycling were very high as compared those during the summer one.

• International Journal of High-Rise Buildings
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• v.10 no.4
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• pp.345-364
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• 2021

Developments in the understanding of fire behaviour for large open-plan spaces typical of tall buildings have been greatly outpaced by the rate at which these buildings are being constructed and their characteristics changed. Numerous high-profile fire-induced failures have highlighted the inadequacy of existing tools and standards for fire engineering when applied to highly-optimised modern tall buildings. With the continued increase in height and complexity of tall buildings, the risk to the occupants from fire-induced structural collapse increases, thus understanding the performance of complex structural systems under fire exposure is imperative. Therefore, an accurate representation of the design fire for open-plan compartments is required for the purposes of design. This will allow for knowledge-driven, quantifiable factors of safety to be used in the design of highly optimised modern tall buildings. In this paper, we review the state-of-the-art experimental research on large open-plan compartment fires from the past three decades. We have assimilated results collected from 37 large-scale compartment fire experiments of the open-plan type conducted from 1993 to 2019, covering a range of compartment and fuel characteristics. Spatial and temporal distributions of the heat fluxes imposed on compartment ceilings are estimated from the data. The complexity of the compartment fire dynamics is highlighted by the large differences in the data collected, which currently complicates the development of engineering tools based on physical models. Despite the large variability, this analysis shows that the orders of magnitude of the thermal exposure are defined by the ratio of flame spread and burnout front velocities (V_S / V_BO), which enables the grouping of open-plan compartment fires into three distinct modes of fire spread. Each mode is found to exhibit a characteristic order of magnitude and temporal distribution of thermal exposure. The results show that the magnitude of the thermal exposure for each mode are not consistent with existing performance-based design models, nevertheless, our analysis offers a new pathway for defining thermal exposure from realistic fire scenarios in large open-plan compartments.

• The Korean Journal of Petroleum Geology
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• v.6 no.1_2 s.7
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• pp.8-19
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• 1998

In the Sinri area located at the mid western boundary of the Jinan basin, the Manduksan Formation which mainly consists of coarse sandstone narrowly intercalated with shale and the alternation of sand and shale and the Dalgil Formation mainly of shale are distributed. It consists of four lithofacies, such as coarse sandstone, interbedded sandstone/shale, shale and volcanic rock lithofacies. All sediments are interpreted to be deposited by turbidity currents and free fallouts in a lacustrine basin. In these rocks many penecontemporaneous defomation structures are observed such as fold and thrust fault at large scale, and swelling, boudin structure, flame structure, load structure, ptygmatic fold and convolute bedding at small scale. All these structures are developed between upper and lower undisturbed sedimentary strata. Two large folds are similar folds, but lower one gradually developed into concentric shape. The swelling structures by convergence of the sediments are observed in the hinge area and the boudin structures are developed in the limb. The thrust faults including minor folds and sandstone lobes show duplex structure with asymmetric and kink fold on and below in front of the detached sandstone layer. Development of the swellings, boudins and lobes indicates the flexbility of the sediments during deformational episodes. The folds and thrust faults rarely contain fractures relative their scales and lithologies. This feature also indicates the retrievability of sediments during deformation. At the flanks of the thrust faults the normal faults are formed contemporaneously. The deformation structures at small scale such as flame structures, load structures, ptygmatic folds and convolute beddings are syndepositional and penecontemporaneous, which show the effects of tectonic movements. All these deformed sedimentary structures of the Sinri area suggest the continuing tectonic movements during and/or after deposition.

• Korean Journal of Heritage: History & Science
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• v.54 no.4
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• pp.152-173
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• 2021

The Large Banner was introduced during the Japanese Invasions of Korea with a new military system. It was a flag that controlled the movement of soldiers in military training. In addition, it was used in other ways, such as a symbol when receiving a king in a military camp, a flag raised on the front of a royal procession, at the reception and dispatch of envoys, and at a local official's procession. The Large Banner was recognized as a symbol of military dignity and training rites. The Large Banner was analyzed in the present study in the context of two different types of decorations. Type I includes chungdogi, gakgi and moongi. Type II includes grand, medium, and small obangi, geumgogi and pyomigi. Each type is decorated differently for each purpose. The size of the flag is estimated to be a square of over 4 ja long in length. Flame edges were attached to one side and run up and down The Large Banner used the Five Direction Colors based on the traditional principles of Yin-Yang and Five Elements. The pattern of the Large Banner is largely distinguished by four. The pattern of large obangi consists of divine beasts symbolizing the Five Directions and a Taoism amulet letter. The pattern of medium obangi features spiritual generals that escort the Five Directions. The pattern of small obangi has the Eight Trigrams. The pattern of moongi consists of a tiger with wings that keeps a tight watch on the army's doors. As for historical sources of coloring for Large Banner production, the color-written copy named Gije, from the collection of the Osaka Prefect Library, was confirmed as the style of the Yongho Camp in the mid to late 18th century, and it was also used for this essay and visualization work. We used Cloud-patterned Satin Damask as the background material for Large Banner production, to reveal the dignity of the military. The size of the 4 ja flag was determined to be 170 cm long and 145 cm wide, and the 5 ja flag was 200 cm long and 175 cm wide. The conversion formula used for this work was Youngjochuck (1 ja =30cm). In addition, the order of hierarchy in the Flag of the King was discovered within all flags of the late Joseon Dynasty. In the above historical study, the two types of Large Banner were visualized. The visualization considered the size of the flag, the decoration of the flagpole, and the patterns described in this essay to restore them to their original shape laid out the 18th century relics on the background. By presenting color, size, material patterns, and auxiliary items together, it was possible not only to produce 3D content, but also to produce real products.