• Tunnel and Underground Space
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• v.13 no.3
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• pp.187-195
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• 2003

This case study which is to make 2-Dimension earth's crust structures clearly is about the great boring-hole blasting to provide ground vibration source of the reflected wave research on the Korean Peninsula earth's crust structures research. For this study we've done blasting twice-500 ㎏/charge per delay, 1,000 ㎏/charge per delay, and the specifications of blasting are the following - dia.: 300 ㎜, boring-depth : 100m, besides, we used the explosives and electric detonators which have sufficient detonating velocity and very excellent safety, capacity of detonating, accurate delay time. We charged explosives into steel pipe with bulk type to avoid dead pressure by ground water. And then we tested about pipe airtight and blasting to certificate which has no problem by using on this study. In the results, we succeeded each blasting in Seosan, Youngdong. For the Peak Sum Vector(PSV) around the blasting at the main points, its real measured PSV is higher 180 % than estimated PSV with USBM. In this study we can't to be analysis of vibration velocity, but to be key providing vibration source.

• Asian-Australasian Journal of Animal Sciences
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• v.20 no.9
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• pp.1462-1467
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• 2007

This study investigated the effect of chemical treatments on tannins (condensed and hydrolysable) and on the trypsin inhibitor (TI) activity in salseed meal. Triplicate samples of ground salseed meal (1 kg) were mixed with 820 ml of either distilled water (pH 5.3), 0.67 M acetic acid (pH 2.4), 0.67 M sodium bicarbonate (pH 8.2) or 2% polyvinyl-pyrrolidone (PVP) solution. The material was placed in airtight plastic containers and incubated at $37^{\circ}C$ for 0, 3, 6, 12, 24, 48 and 72 h. Samples of untreated salseed meal which had not been subjected to soaking or incubation were run through the analysis to serve as control. Addition of water, acetic acid, sodium bicarbonate and PVP solutions to salseed meal and subsequent anaerobic incubation at $37^{\circ}C$ significantly reduced chemically detectable tannins. At each incubation time, alkali solution was more effective than its counterparts. The effect of acidic solution on hydrolysable tannin was least among the treatments. All the treatments reduced TI activity of salseed meal. The reduction in TI activity by these treatments was similar and ranged between 80-84%. Treatment time effected a decrease in the contents of antinutritional substances. However, the effect of the treatment with the reagents, even for zero incubation time, was quite pronounced. It may be concluded from the present results that the treatment of salseed meal with sodium bicarbonate (0.67 M) is more effective in reducing hydrolysable and condensed tannin contents than PVP, water and acid solutions. Treatment with sodium bicarbonate solution is more economical and easier to handle than acid and PVP treatments. Incubation of the treated material for 12 h is reasonably effective, economical and safe from any mould growth.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.2
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• pp.164-168
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• 2014

To determine the optimal storage method and longest possible storage period of Zostera marina seeds, we examined post-storage germination rates using different storage methods and periods for Z. marina seeds harvested in southern coast of Korea. Storage methods included in seawater at room temperature with air supply, seawater at $4^{\circ}C$, seawater at $30^{\circ}C$, an aquarium with continuous seawater circulation, seawater at room temperature in an airtight tank, a refrigerator at $-20^{\circ}C$, and a desiccator at room temperature. Germination rates of Z. marina seeds stored in seawater at $4^{\circ}C$ showed highest germination (52.0%), whereas those of seeds stored in seawater at room temperature and an aquarium were 27.4% and 17.7%, respectively. But the seeds stored in seawater at $30^{\circ}C$, a refrigerator, and a desiccator did not germinate. Storage periods were 10, 20, 30, 60, 180 and 240 days of storage. Z. marina seeds maintained germination rates of 46.4~52.4% until 10~60 days of storage, but showed rapidly decreasing germination rates after then and no germination after 240 days.

• Tribology and Lubricants
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• v.34 no.5
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• pp.197-207
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• 2018

Thermal deterioration of fuel due to long-term storage influences engine performance and causes malfunctions. Fuel stability is usually evaluated via heat resistance and thermal stability during a brief heat shock at high temperature; storage stability in this scenario means that there is very little change in the quality of the fuel during long-term storage. In addition, rubber-based products such as oil seals, O-rings, and rubber hoses can influence the quality of the fuel. When these rubber products are in contact with fuel, they can swell, mechanically weaken, and occasionally crack, thus leaking low molar weight rubber and additives including plasticizer and antioxidant into the fuel to degrade its properties and shorten its useful lifetime. This study determines the thermal stabilities of three kinds of synthetic fuels by evaluating their low temperature kinematic viscosities, chemical composition changes via GC analyses, gross heat of combustion, and color changes. We evaluate the compression set of O-rings by immersing one NBR and two FKM rubber O-rings in the three synthetic fuel samples in airtight containers at variable storage temperatures for six months; from this, we estimate the lifetimes of the O-rings using the Power law model. There were very little changes in the chemical compositions and gross heat of combustion after six months of the experiment. The lifetimes are thus dependent on the materials of the rubber products, and in particular, the FKM O-ring was calculated to have a theoretical lifetime of 200 to 5,700 years. These results indicate that the synthetic fuels maintain their physical properties even after long-term storage at high temperatures, and the FKM O-ring is suitable for long-term sealing of these fuels.

• Journal of Biosystems Engineering
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• v.6 no.2
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• pp.1-8
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• 1982

The objective of this study was to find out the technical feasibility of ethanol-diesel fuel blends as a diesel engine fuel. Fuel properties essential to the proper operation of a diesel engine were determined for blends containing several concentrations of ethanol in No. 2 diesel fuel. A single-cylinder diesel engine for a power tiller was used for the engine tests, in which load, speed and fuel consumption rate were measured. The fuels used in tests were No. 2 diesel fuel and a blend containing 10-percent ethanol and 90-percent No. 2 diesel fuel. The results of the study are summarized as follows. 1. It was not possible to blend ethanol and No. 2 diesel fuel as a homogeneous solution even though anhydrous ethanol was used. The problem of blending ethanol in No. 2 diesel fuel could be solved by adding butanol about 5% of the amount of ethanol in the blends. 2. Because ethanol had a much lower boiling point ($78.3^{\circ}C$ under atmospheric pressure) than a diesel fuel, it was necessary to store ethanol-diesel fuel blends airtight in order to prevent them from evaporation losses of ethanol. 3. The addition of ethanol to No. 2 diesel fuel lowered the fuel viscosity and the cetane rating, but a blend of 10% ethanol and 90% diesel fuel had a viscosity and a cetane rating well above the KS minimum values for No. 2 diesel fuel. 4. At the rated speed, the specific fuel consumption of No.2 diesel fuel was lower than that of the 10% ethanol blend for the almost entire range of load. However, under the overload condition the specific fuel consumption was lower for the 10% ethanol blend. 5. Under the variable-speed full-load tests, both fuels produced approximately the same torque and power. At the speeds of 1600rpm or below, the specific fuel consumption of No. 2 diesel fuel was lower than that of the 10% ethanol blend. At the speeds of 1600rpm or above, however, the specific fuel consumption was lower for the 10% ethanol blend. 6. At the ambient temperature above $15^{\circ}C$, the use of the 10% ethanol blend in the engine created a vapor lock in the fuel injection pump and stalled the engine. The vapor locking problem was overcome by chilling the surroundings of the fuel injection pump and the cylinder head with water.

• Journal of Bio-Environment Control
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• v.18 no.3
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• pp.185-191
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• 2009

The construction of experimental greenhouses, operating test, and analysis on variation of different environment factors were conducted to provide fundamental data for design of Korean style air-inflated double-layer plastic greenhouse. The development of technology of attaching plastic to the structure and fasteners to be able to keep airtight was required in order to maintain proper static pressure in air space of double layer coverings. The insulation effect of air inflated greenhouse was better than conventional type. The temperature of arch type roof was greater about $2^{\circ}C$ than peach type roof in air inflated greenhouse. It was recommended that the plastic should be attached at the edges without clearance length in order to ease installation and raise airtightness of double layer coverings. The transmittance of arch type roof was greater than peach type in air inflated one span greenhouse. The transmittance of air inflated greenhouse was greater than conventional type due to frame ratio and distance between double layers in three span greenhouse. The condensation occurred on conventional type greenhouse was more than air inflated type. It was required to examine for a long time in order to analyze it quantitatively.

• Asian-Australasian Journal of Animal Sciences
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• v.17 no.11
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• pp.1541-1552
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• 2004

The effect of eight varieties of whole crop rice silage (WCRS) harvested at four stages of maturity were investigated for in situ DM and N degradability, ME and MP yield and content in an 8${\times}$4 factorial experiment. The varieties were Akichikara, Fukuhibiki, Habataki, Hamasari, Hokuriku 168, Kusanami, Tamakei 96 and Yumetoiro. Hamasari and Kusanami were forage varieties while all others were grain varieties. Forages were harvested on 10, 22, 34 and 45 days after flowering, ensiled and kept in airtight condition. Between 45 and 49 days after ensiling, silages opened, chopped and milled green to pass through 4 mm screen. Samples were incubated in the rumen of two Holstein steers for 0, 3, 6, 9, 12, 24, 48, 72 and 96 h over eight 4 d periods. Bags at 0 h were washed in a washing machine. Variety affected DM (p<0.001: except 'a+b', p<0.01) and N (p<0.001) degradability characteristics of WCRS. Stages of maturity also affected DM (p<0.001: except 'a+b', p<0.05; 'c', p<0.08) and N (p<0.01: except 'c', p<0.05) degradability characteristics of WCRS. Interactions between variety and stages of maturity occurred in all DM (p<0.001) and N (p<0.001) degradability characteristics except (p>0.05) for DM 'b', DM 'c', DM 'a+b' nd N 'c'. Effective DM degradability was higher in grain varieties than forage varieties and degradability increased with maturity. N availability decreased only slightly with maturity. Variety was the key factor for N degradability characteristics of WCRS since variety accounted for most of the total variation for degradability characteristics. Both ME and MP content and yield were higher (p<0.001) in grain varieties, and they increased (p<0.001) with the maturity. The results clearly demonstrated that the grain type varieties contained higher ME and MP content than forage varieties, and increase in maturity increases both ME and MP content of WCRS.

• Asian-Australasian Journal of Animal Sciences
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• v.15 no.8
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• pp.1128-1133
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• 2002

The whole plant of crop maize was chopped and ensiled in airtight 1-L capacity glass jars to determine the influence of residual sugar on anaerobic yeast growth and on the fermentation of lactic acid by L. buchneri in whole crop maize silage. There were a total of six treatments used in this experiment as follow: added 25 g de-mineralised water per kg chopped maize serving as control (con), 37.5 g glucose solution containing 12.5 g glucose ($g_1$), 75 g glucose solution containing 25 g glucose ($g_2$), 25 g L. buchneri suspension intended for $10^6$ cfu $g^{-1}$ (L.b.), $g_1+L.b.$ and $g_2+L.b.$ All silos were stored in the dark at $20^{\circ}C$ until end of experiment. Jars were opened on duplicates at day 2, 7, 14, 28, 56 or triplicates at day 91 after ensiling for measuring the pH, microbiological enumeration and fermentative products. Results indicated that acidification rates for all silages were very fast, no difference occurred among treatments before day 28. After day 28 the pH values for silages inoculated by L. buchneri. with or without sugar tended to increase especially for treated only with L. buchneri, resulting in higher (p<0.01) finial pH than uninoculated silages. Compared with control silage, the added sugar significantly (p<0.01) increased dry matter (DM) loss, L. buchneri enhanced (p<0.01) DM loss further at different sugar existence. Silages inoculated by L. buchneri only or in combination with sugar addition contained less (p<0.01) lactic acid than the correspondent silages without inoculation with L. buchneri. In comparison with control, ethanol production is about 3 or 6 fold higher due to addition 12.5 or 25 g glucose per kg chopped maize at ensiling. The added sugar resulted in less acetic acid concentration (p<0.01) than control, but inoculation with L. buchneri increased (p<0.01) acetic acid than correspondent uninoculated silages at different sugar levels. No butyric acid and propionic acid were found in uninoculted silages, silages inoculated with L. buchneri. produced more propionic acid, 1-propanol and butyric acid. Lactobacilli counts were not influenced by added sugar, but increased (p<0.01) with inoculation of L. buchneri. The added sugar increased significantly (p<0.01) the yeast count, whereas L. buchneri showed the contrary effect. No differences were found in the aerobic stability among all treatments. In conclusions, 1) the added sugars encourage the growth of yeast and yeasts convert extra sugar into ethanol in maize silages. 2) The added sugars and L. buchneri do not influence the aerobic stability of silages stored in anaerobic silos.

• The Korean Journal of Mycology
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• v.3 no.2
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• pp.19-23
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• 1975

A study on the variation of the air temperature in the pine mushroom box containing dry ice for the preservation of the freshness of the pine mushroom, Tricholoma matsutake (Ito et Imai) Sing. produced in Korea was made in Seoul, Korea during the period of August 1 to 30, 1975. A safe shipment of 5 kg (net weight) of fresh mushrooms with freshness preserved for 24 hours in August required the placement of 4.5 kg of dry ice-a half in the upper portion and the other half in the middle portion-in an airtight container (mushroom box). The container used for the shipment test, made of 3mm-thick double-layer cardboard, was of the dimensions : $0.33{\times}0.4{\times}0.5=0.066(m^3)$. As the temperature fell, decreased amounts of dry ice were needed : 3 to 2 kg in September and 1.5 to 0.3 kg in October. With this preservation method, large quantities of fresh mushrooms were exported to Tokyo ana Osaka, Japan without damage in the process of transportation.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.6
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• pp.2596-2603
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• 2013

The precision and endurance of tire mold are very important factors to decide the quality of tire. However, the investigation on the thermal deformation of tire mold has a lot of trouble because the tire mold is produced in airtight permanent casting material. In this study, the thermal deformations such as temperature, displacement and stress distributions inside the AC7A tire mold casting material were analyzed by numerical analysis according to the preheating temperature of permanent casting device. In order to verify the results of numerical analysis, the experiments for temperature measurement of the AC7A casting material were carried out under the same condition with numerical analysis. For the numerical analysis, "COMSOL Multiphysics" was used. The preheating temperatures were set up $150^{\circ}C$, $200^{\circ}C$, $250^{\circ}C$ and $300^{\circ}C$, respectively. The thermal deformations were calculated in each case. When the preheating temperature is $300^{\circ}C$, displacement and stress are the lowest with 0.25mm and 0.351GPa, but the temperature is the highest with $374.27^{\circ}C$. When the experimental results were compared with the numerical results, there were some temperature differences because of the latent heat by phase change heat transfer. However, the cooling patterns were almost similar except for the latent heat section.