• Journal of the Korean GEO-environmental Society
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• v.14 no.7
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• pp.51-56
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• 2013

Recently, a top record of hourly-based rainfall has been changed annually and flood damages of road have increased. To solve this problem, pavements for drainage were developed and practically constructed but there was no considerations on sub-base. In this research, we proposed standard for distribution of particle size of sub-base to consider strength characteristic and drainage property. We focused to compare coefficients strength and permeability by laboratory tests. Prior to tests, 4 samples were selected under the consideration on the international or domestic design guideline. In the tests, strength characteristics were compared with resilient modulus. Also, permeability characteristics were compared with coefficient of upward and downward permeability. Resilient modulus was determined with MR test using cyclic triaxial testing system. Two permeability tests were carried out. One is variable head permeability test for downward drainage and the other is Rowe Cell test for upward drainage. In the case of Rowe Cell test, middle-sized sampler with 150mm diameter was used for this study. Consequentially, we tried to find the optimum distribution of particle size to satisfy both of strength and permeability characteristics for sub-base.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.54 no.2
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• pp.203-209
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• 2009

Yield monitoring is one of a precision agriculture technology that is used most widely. It is spatial variability analysis of yield information that should be attained with yield monitoring system development. This experiment was conducted to evaluate spatial variability of yield and grain moisture content in rice paddy field, and their relationships to rice productivity. It is necessary to minimize sampling interval for accurate yield map making or to control cutting width of rice combine. Considering small rice plots such as $0.2{\sim}0.4$ ha, optimum size of sampling plot was below 15 m more than 5 m in with and length. In variable rate treatment field, average yield was similar, but yield variation was reduced than conventional field. Gap of yield by another plot in same field was bigger than half of average yield than yield variation was significantly big. Therefore yield measuring flow sensor must be able to measure at least 300 kg/10a more than 1000 kg/10a. Variation of moisture content in same field was not big and spatial dependance did not appear greatly. But, variation between different field is appeared difference according to weather circumstance before harvesting. Change of spatial dependence of yield was not big, because of field variation of moisture content is not big.

• KOREAN JOURNAL OF PACKAGING SCIENCE & TECHNOLOGY
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• v.19 no.2
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• pp.87-94
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• 2013

To investigate the effects of functional MA films (FMA) masterbatched by zeolite powder treated with 1 N HCl, 0.5 N NaCl solution and anti-fogging agent (NA) compared with control on the freshness extension of 'Fuji' apples during storage at $15^{\circ}C$. Preference, weight loss, total ascorbic acid, sugar content, acidity, change of gas composition in package were measured. After 150 days of storage, the weight loss of control (L) apples was 1%, that of apple in FMA film (NA) was 1.5% after 150 days. Total ascorbic acid content of apples in control (L) after 150 days was 2.09 mg%, those of apple in FMA film (NA) was 2.72 mg%. The titratable acidity of apple in FMA film was higher than that in control, while soluble solids content of apples in FMA film was lower than that in control after 150 days. Ethylene gas adsorbability in control was 192.2 ppm and those in FMA film was 141.4 ppm after 150 days. Overall, apples in FMA film was better than that of control. It was verified that apples packed with LLDPE film (control) lasted about 130days, while those with FMA films lasted about 170 days. Also, FMA films treated with anti-fogging agent few different compare to nontreated film, but commerdity on the display in market was considered higher than that of non-treated anti-fogging agent.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.625-628
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• 2008

Size-effect correction factors of the flexural test specimens, which had controled cement concrete pavement quality, were investigated and derived to be easily used in field. We couldn't find the size-effects in this size range (10, 12, 15cm) of specimens, which were made of 32mm crushed aggregates, and the theoretical verification was presented by Bazant's equations. Finally, non-dimensional chart for size-effect correction was proposed, covering the relationship between compressive strengths and w/c ratios.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.10 s.115
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• pp.1067-1073
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• 2006

In this paper, we present noise measurement results of 8 vehicles. The measurement was done by a close proximity method attaching surface microphones on the test vehicle. For the 9 road surface types constructed at Korean highway test road, the vehicles were tested from 50 to 120 km/h at the interval of 10 km/h in normal steady state and inertia cruising conditions. Using the results, we evaluate and discuss the effect of vehicle noise generation depending on the different conditions for vehicle type, speed, road surface and loading condition, especially focused on friction noise between tyre and road surface.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.428-433
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• 2006

In this paper, we present noise measurement results of 8 vehicles. The measurement was done by a close proximity method attaching surface microphones on the test vehicle. For the 9 road surface types constructed at Korean highway test road, the vehicles were tested from 50 to 120 km/h at the interval of 10 km/h in normal steady state and inertia cruising conditions. Using the results, we evaluate and discuss the effect of vehicle noise generation depending on the different conditions for vehicle type, speed, road surface and loading condition, especially focused on friction noise between tyre and road surface.

• Proceedings of the Korean Society of Disaster Information Conference
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• 2016.11a
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• pp.353-356
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• 2016

불투수성 방수아스팔트는 아스팔트 혼합물이 골재와 골재 사이를 강력하게 부착하며, 골재간의 공간을 메우고, 골재표면을 두껍게 코팅하여 골재 상호간의 강한 접착을 유지시켜주는 열가소성 폴리머를 사용한 포장공법이다. 이러한 불투수성 아스팔트는 기존의 가열식 일반아스팔트 공법에서 문제시 되고 있는 내구성 저하와 잦은 유지보수로 인한 문제점을 해결할 수 있는 공법으로 차세대 고내구성 포장공법으로 주목을 받고 있다. 본 연구는 불투수성 방수아스팔트 혼합물 개발을 위한 연구의 일환으로 상온과 영하 $10^{\circ}C$의 조건하에서 기존 아스팔트수지와 새로운 개념의 불투수성 고분자계 수지의 부착성능 비교 검토하였으며, 아스팔트혼합물의 부착성능도 실험을 통해 비교 하였다. 실험결과 불투수성 아스팔트의 부착성능이 기존 아스팔트에 비해 상온은 물론 저온에서도 뛰어난 성능을 발휘하는 것을 확인 하였다.

• Proceedings of the Korean Society of Postharvest Science and Technology of Agricultural Products Conference
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• 2003.10a
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• pp.189.1-189
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• 2003

‘부유’단감은 국내에서는 일반화되어 있는 PE필름 밀봉 저장방식으로 과실의 호흡에 의해 산소농도의 감소와 이산화탄소의 증가로 호흡이 억제되고 이에 따라 노화가 지연됨으로 과실의 저장수명을 증가시키는 방식이며, 최적저장온도는 -0.5~$0^{\circ}C$라고 보고되고 있다. 이에 본 실험에서는 상온유통을 고려하여 2$0^{\circ}C$에서 0.03mm, 0.05mm LDPE필름으로 포장한 경우와 무포장한 경우를 비교하여, 중량, 수소이온농도, 가용성고형분, 경도를 측정하고 이를 외관품질검사 결과와 종합적으로 검토하였으며, 또한 환경기체조성의 범위를 설정하기 위하여 산소농도(1~5%), 이산화탄소농도(5~15%)를 독립변수로 중심합성계획법(central composite design)에 의해 3단계로 부호화하였고 산소소비농도, 이산화탄소 발생속도, pH 당도, 경도를 종속(반응)변수로 결과를 이용하여 독립변수와 종속변수간의 함수관계를 규명하며, 독립변수들의 값의 변화에 따라서 반응량(종속변수)이 어떻게 달라지는 가를 예측하며, 독립변수가 종속변수인 반응량을 최적화(Optimize) 하는가와 어떤 실험계획법을 쓰면 가장 좋은 정도를 얻을 수 있는지를 규명하고자 한다.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.11a
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• pp.765-768
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• 2008

The prevent methods of Alkali-Silica Reaction (ASR) are studying after the failure cases by ASR were reported in Korea. When ASR failure is causing to the step of maintenance, the available repair methods were rarely studied in the World. In this study, premixed fly ash cement was applied to prevent ASR in the concrete pavement. The ratio of fly ash and cement is 20 percent and 80 percent by weight of total cementious material. The construction performance of premixed fly ash cementious concrete pavement was studied that the application is verify to performance collected data during the constructing in the field. The freeze-thaw test was studied to verify durability of the premixed fly ash cementious material made specimen in the laboratory. The results show that construction performance and durability are well condition in this test section and freeze-thaw test.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.36 no.6
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• pp.1109-1116
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• 2016

There are various test methods for evaluating the reflective cracking resistance of asphalt concrete pavement. Repeated direct tensile test is cheap and simple compared to the other traditional experimental methods. Determination of failure criteria is needed to apply a repeated direct tensile test. Various methods were used to determine the number of failure of repeated direct tensile test. The number of failure was defined as the time to reach 10% of the initial load, this method can be satisfied with specified tolerance of 10%. When the thickness of specimen is increased to 50 mm from 30 mm, the failure number is increased by 13.6 times. Thus, this result shows that the thickness of pavement is a big influence on the reflective cracking resistance. Reflective cracking resistance of asphalt concrete is decreased according to the increase in opening displacement. The repeated direct tensile test can be used as a reflective cracking resistance factor in pavement design, because it can evaluate the reflective cracking resistance according to the pavement thickness, opening displacement, material properties etc.