• Journal of Korean Tunnelling and Underground Space Association
• /
• v.26 no.2
• /
• pp.91-111
• /
• 2024

Most of utility cable tunnels are constructed utilizing shield TBM as part of the underground transmission line project. The TBM chamber is the only space inside the tunnel that encounters rock and soil, and is the place with the highest frequency of accident exposure, such as collapse and collision accidents. Since there is currently no way to measure the disc cutter wear from outside the chamber, frequent inspection by workers is essential. Accordingly, in this study, in order to prevent safety accidents inside the TBM chamber and expect the effect of shortening the construction period by reducing the number of chamber openings, the concept of disk cutter wear measurement technology was established and a prototype was produced. By considering prior technology and determining that magnetic sensors are most suitable for the excavation environment, wear measurement sensor package were developed integrating magnetic sensors, wireless communication modules, power supply, external casing, and monitoring systems. To verify the performance of the prototype in an actual excavation environment, a full-scale tunnelling test was performed using a 3.6 m EPB shield TBM. Based on the full-scale tests, five prototypes were operated normally among eight prototypes. It was analyzed that sensor measurement, wireless communication, and durability performance were secured within a maximum thrust of 3,000 kN and a rotation speed of 1.5 RPM.

• Journal of Korean Society of Forest Science
• /
• v.10 no.1
• /
• pp.29-39
• /
• 1970

Forest fires often destory forests that have taken years to grow in a few minutes. Forest fire therefore, is an important problem in forest management and have caused heavy losses to the nations economy. In order to resolve this problem many investigations have been made in many countries. However, ecological studies on the forest after accidental fire have not yet been made in Korea. In order to conduct such a study, a burned area on Mt. Samak which is located at Dukduwon-ri, Seo-myon, Chunsung-gun, Kangwon-do, was chosen as experimental plot in 1967. The remaining seeds were collected from the burned area, and investigations on their germination rate and their productivity were made comparing to those of the seeds of undemaged area, and following results were obtained. 1. The number of seed collected from the control plots were 740 while it was 537 from the test plots (Table 3, 4). It was considered that this difference between burned and unburned area was mainly due to the fact that some of the seeds had been burnt by the fire, and the unfavorable environmental conditions in the burned area was also considered to be a reason. In the germination rate in the control plots showed 28.1% while it was 3.2% in the test plots. This difference was considered to be due to complete loss of viability of the seed by burning and high heat. 2. In the test plots, sixteen seeds of the Alnus japonica were collected and six of these seeds germinated (index number 100) which was the highest germination rate among the species of collected seeds. From these results, it was considered that a high temperature (above $150^{\circ}C$) caused reduction of the germination rate (Quadrat. 1.2). Seeds of Carex lanceolata var. Nana, were appeared much more in the higher plots than in the lower plots and it seemed to be due to the fact that the forest floor plants were much more abundant in the lower plots than in the higher plots which is covered with shrubbery. And some small seeds midght be able to avoid the effect of fire being burried in the soil or under the gravel. 3. With Pinus densiflora, 43 seeds were collected, and 11 of these germinated in the control plots. However in the test plots, 11 seeds were collected and no seed germinated. This shows that the Pinus densiflora was the weakest in resisting to heat among the observed species in this study. 4. Without exception the germination rate showed a higher index in the herbs than in the woody plants and it is believed that the herbs produced more seed than the wood plants because of the abundance of herbs colony.

• The Korean Journal of Pesticide Science
• /
• v.19 no.3
• /
• pp.174-184
• /
• 2015

In the present study, the metabolism of [$^{14}C$]butachlor was investigated in rice plant according to the OECD test guideline No. 501. [$^{14}C$]Butachlor was treated as granule to paddy water by application of 1.5 kg ingredient (a.i.)/ha at the 3~4 leave stage of rice plant. At 85 days after treatment (DAT), samples of panicle, foliage, and roots were taken for radioactivity analysis. Upon harvest at 126 DAT, rice plants were separated into brown rice, husk, straw, and root parts. Amounts of total radioactivity absorbed by rice plant ranged from 8.6 to 9.8% of applied radioactivity (AR). Total radioactive residues (TRRs) of rice plant at 126 DAT was the highest as 4.0421 mg/kg (7.3% AR) in the straw followed by 1.4595 mg/kg (2.4% AR) in the root, 0.7257 mg/kg (0.1% AR) in the husk. The lowest level recording 0.1020 mg/kg (0.1% AR) was found in brown rice. Each part was extracted with various solvents and solvent/water mixtures. Greater than 70% of TRRs was readily extractable from foliage, panicle, husk and straw. Only 34.0% of the brown rice and 43% of root based on TRRs were extractable showing that the residues were completely assimilated in the plant tissue. The level of non-extractable radioactivity was ranged from 26.2 to 66.0% of TRRs. From this study, five tentative major metabolites (M1, M2, M3, M4 and M5) were observed in rice extracts. Among the metabolites, 2,6-diethylaniline assigned as M4 was identified in rice plant by comparing to retention time of reference standard. Un-metabolized butachlor was not detected in any fractions. In soil extracts, N-(butoxymethyl)-N-(2,6-diethyl phenyl)acetamide, 2,6-diethylaniline, M2, M3 and M5 were observed. And the concentration of butachlor was low level (ca. 0.03 mg/kg).

• Economic and Environmental Geology
• /
• v.38 no.6 s.175
• /
• pp.717-729
• /
• 2005

Peak cooling load of large buildings is generally greater than their peak heating load. Internal and solar heat gains are used fur selection of adquate equipment in large building in cold winter climate like Canada and even Korea. The cost of geothermal heat exchanger to meet the cooling loads can increase the initial cost of ground source heat pump system to the extend less costly conventional system often chosen. Thermal ice storage system has been used for many years in Korea to reduce chiller capacity and shift Peak electrical time and demand. A distribution system designed to take advantage of heat extracted from the ice, and use of geothermal loop (geothermal heat exchanger) to heat as an alternate heat source and sink is well known to provide many benifits. The use of thermal energy storage (TES) reduces the heat pump capacity and peak cooling load needed in large building by as much as 40 to $60\%$ with less mechanical equipment and less space for mechanical room. Additionally TES can reduce the size and cost of the geothermal loop by 1/3 to 1/4 compared to ground coupled heat pump system that is designed to meet the peak heating and cooling load and also can eliminate difficuties of geothermal loop installation such as space requirements and thermal conditions of soil and rock at the urban area.

• Geotechnical Engineering
• /
• v.14 no.3
• /
• pp.25-46
• /
• 1998

This paper shows that there are the results of a series of model tests on the behavior of single pipe pile which is subjected to lateral load in, Nak-dong River sand. The purpose of the present paper is to estimate the effect of Non-homogeneity. constraint condition of pile head, lateral load velocity, relative density, and embedded length of pile on the behavior of single pile. These effects can be quantified only by the results of model tests. Also, these are compared with the results of the numerical methods (p-y method, modified Vlasov method; new ${\gamma}$ parameter, Characteristic Load Method'CLM). In this study, a new ${\gamma}$ parameter equation based on the Vlasov method was developed to calculate the modulus of subgrade reaction (E. : nhz.) proportional to the depth. The p-y method of analysis is characterized by nonlinear behavior. and is an effective method of designing deep foundations subjected to lateral loads. The new method, which is called the characteristic load method (CLM). is simpler than p-y analysis. but its results closely approximates p-y analysis results. The method uses dimensional analysis to characterize the nonlinear behavior of laterally loaded piles with respect to be relationships among dimensionless variables. The modulus of subgrade reaction used in p-y analysis and modified Vlasov method obtained from back analysis using direct shear test (DST) results. The coefficients obtained from DST and the modified ones used for the prediction of lateral behavior of ultimate soil reaction range from 0.014 to 0.05. and from 0.2 to 0.4 respectively. It is shown that the predicted numerical results by the new method (CLM), p-y analysis, and modified Vlasov method (new parameter) agree well with measured results as the relative density increases. Also, the characteristic load method established applicability on the Q-Mnu. relationship below y/D=0.2.

• The Korean Journal of Pesticide Science
• /
• v.14 no.4
• /
• pp.463-472
• /
• 2010

It was conducted to investigate the control efficacy of carboxylic acid amide (CAA) fungicides, such as benthiavalicarb, iprovalicarb, dimethomorph and mandipropamid, against pepper Phytophthora blight caused by P. capsid in the laboratory and the field. The fungicides inhibited mycelial growth and direct sporangium germination of P. capsid strongly, while there was no activity of all fungicides against zoospore release from sporangium. In greenhouse test, they showed the good protective and curative effect against pepper Phytophthora blight. Benthiavalicarb applied at $100{\mu}g\;mL^{-1}$ 7 days before inoculation prevented pepper Phytophthora blight by 100%, even though the zoosporangiurn suspension of P. capsid adjusted to not only $5{\times}10^3$ zoosporangia $mL^{-1}$ but also $1{\times}10^5$ zoosporangia $mL^{-1}$ was inoculated by soil-drenching. Except for dimethomorph, the other fungicides showed an excellent control activity over 2 years from 2009 to 2010 in the field test. The control value of dimethomorph applied at $250{\mu}g\;mL^{-1}$ was low, 27.2% in 2009, but that of dimethomorph applied even at $125{\mu}g\;mL^{-1}$ was high, 89.5% in 2010. All the fungicides showed good inhibitory effect on the mycelial growth and the direct germination of zoosporangiurn, and controlled pepper Phytophthora blight preventively and curatively, can be used to establish the spray system for control1ing the pepper disease.

• Research in Plant Disease
• /
• v.15 no.2
• /
• pp.72-76
• /
• 2009

It was investigated the responses of BaYMV resistant genes to Korean BaYMV(Barley yellow mosaic virus) strains. BaYMV was distributed dominantly with about 51% detection ratio among the three investigated virus such as BaYMV, BaMMV(Barley mild mosaic virus) and SBWMV(Soil-borne wheat mosaic virus) in ELISA test. Double infection with BaYMV and BaMMV was detected also higher as 38.8%, however, BaMMV sole infection ratio was lower with only 1.4%. The 11 BaYMV resistant genes were tested their responses to four Korean BaYMV strains, BaYMV-N, H, I and M. Generally, rym 3 genes showed resistant to Korean BaYMV strains and rym 4m and 5a also was better. Three genes, rym 1+5(Mokusekko-3), rym 3(Ea 52, Baitori) and rym 5a(Solan) showed resistant responses to BaYMV-N type. In -H strain test, seven genes that rym 2(Mihori Hadaka 3), rym 3(Ea 52, Haganemugi, Baitori), rym 4m(Diana, Franka), rym 5a(Solan), rym 7(Hor 3365), rym 9(Bulgarian 347), rym 12(Jochiwon Covered 2) were considered as resistant. The three genes that rym 1+5, rym 3 and rym 5a was effective to -I strain, and rym 3, rym 4m and rym 5a showed resistant to -M strain.

• The Journal of Engineering Geology
• /
• v.24 no.1
• /
• pp.111-122
• /
• 2014

For accurate laboratory evaluations of soil deposits, it is essential that the samples are undisturbed. An artificial ground-freezing system is the one of the most effective methods for obtaining undisturbed samples from sand deposits. The objective of this study is to estimate the shear strengths and the characteristics of elastic waves of frozen-thawed and unfrozen specimens through the undrained triaxial compression test. For the experiments, Jumunjin standard sands are used to prepare frozen and unfrozen specimens with similar relative densities (60% and 80%). The water pluviation method is used to simulate the fully saturated condition under the groundwater table. When thawing the frozen specimens, the temperature is measured every minute. After the specimens are completely thawed, undrained triaxial compression tests are conducted using the same procedures as for the unfrozen specimens. During the triaxial tests (saturation, consolidation, and shear phase), compressional and shear waves are measured. The results show that the freeze-thaw process has minor effects on the peak deviatoric stress and shear strength values, and that the process does not affect the internal friction angle. The compressional wave velocity increases with increasing B-value to 1800 m/s in the saturation phase, but tends to remain constant in the process of consolidation and shearing. The shear wave velocity decreases with increasing B-value in the process of saturation, but changes velocity in accordance with the change in effective stress in the processes of consolidation and shearing. The compressional wave velocity has similar values regardless of the freeze-thaw process, but values of shear wave velocity are slighly lower in frozen-thawed specimens than in unfrozen specimens. This study is a preliminary experiment for estimating the shear strength and characteristics of elastic wave velocity in undisturbed frozen specimens that have been obtained using the artificial ground-freezing method.

• Journal of Sericultural and Entomological Science
• /
• v.49 no.2
• /
• pp.51-55
• /
• 2007

Investigation of atmospheric data and rearing results was conducted to analyze the effects of atmospheric factors such as temperature and precipitation on silkworm in 8 rearing places in which local adaptation test was being conducted with different mulberry growth condition, soil and atmosphere during spring and autumn rearing season of 2006. The atmospheric characteristics of spring rearing time are as follows. The average temperatures of young silkworm, old silkworm, mounting were $17.7^{\circ}C$, $19.8^{\circ}C$, $21.5^{\circ}C$ respectively, and $1^{\circ}C$ higher than normal year. The precipitation of young silkworm, old silkworm, mounting were 15.1 mm, 6.9 mm, 7.0 mm, respectively, and 22.9 mm lower than normal year in old silkworm and mounting. The daylight hours in larval stage was 1.7 hour shorter than normal year, but no difference in mounting. Thus precipitation was lower and temperature was higher than normal year in 2006. The rearing results of 2006 were 1 kg lower than normal year in cocoon yields per 10,000 3 rd molted larvae, single cocoon weight and cocoon shell percentage were a little higher. The atmospheric characteristics of spring rearing season are as follows. The average temperatures of young silkworm, old silkworm, mounting were $25.1^{\circ}C$, $20.5^{\circ}C$ and $19.9^{\circ}C$ respectively, temperature in young silkworm was $1^{\circ}C$ higher than normal year, and temperature in old silkworm was $1.3^{\circ}C$ lower than normal year. The precipitation of young silkworm, old silkworm, mounting were 110.2 mm, 4.6 mm, 3.7 mm, respectively and there were little differences compared to normal year. The atmospheric condition of 2006 which was similar to normal year did not affect the autumn rearing results of 2006. Namely, the single cocoon weight and cocoon shell weight were not different from normal year, and the same was cocoon shell percentage.

• Korean Journal of Breeding Science
• /
• v.40 no.3
• /
• pp.308-313
• /
• 2008

"Jeokjoong", a white winter wheat (Triticum aestivum L.) variety was developed from the cross "Keumkang"/"Tapdong". "Jeokjoong" is an awned, semi-dwarf and soft white winter wheat, similar to "Keumkang" (check variety). The heading and maturing date of "Jeokjoong" were similar to "Keumkang". Culm and spike length of "Jeokjoong" were 78 cm and 7.5 cm, similar to "Keumkang". "Jeokjoong" had lower test weight (800 g) and lower 1,000-grain weight (40.1 g) than "Keumkang" (811 g and 44.0 g, respectively). It had resistance to winter hardiness, wet-soil tolerance and lodging tolerance. "Jeokjoong" showed moderate to scab in test of specific character although "Keumkang" is susceptible to scab. "Jeokjoong" had lower flour yield (69.2%) and ash content (0.36%) than "Keumkang" (72.0% and 0.41%, respectively) and similar flour color to "Keumkang". It showed lower protein content (8.9%) and SDS-sedimentation volume (36.8 ml) and shorter mixograph mixing time (3.5 min) than "Keumkang" (11.0%, 59.7 ml and 4.5 min, respectively). Amylose content and pasting properties of "Jeokjoong" were similar to "Keumkang". "Jeokjoong" had softer and more elastic texture of cooked noodles than "Keumkang". Average yield of "Jeokjoong" in the regional adaptation yield trial was 6.19 MT ha-1 in upland and 5.33 MT/ha in paddy field, which was 19% and 16% higher than those of "Keumkang" (5.21 MT/ha and 4.58 MT/ha, respectively). "Jeokjoong" would be suitable for the area above the daily minimum temperature of $-10^{\circ}C$ in January in Korean peninsula.