• 한국환경복원기술학회지
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• 제11권4호
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• pp.119-128
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• 2008

In this study, we attempted to seek out the ways to recycle fresh root-chips in the slope revegetation works by breaking tree root wastes occurring during the construction works, also to review the applicability of fresh root-chips as the soil media in slope revegetation works. For this purpose, we organized test units in order to investigate on-site applicability of fresh root-chips (broken chips). In order to examine the desirable ration of combining fresh root-chips with the hydroseeding soil media on the cutting slopes, we organized test units depending on the amount of combination. The following is the main experimental results. 1. At first, we analyzed properties of hrdro-seeding soil media and soil of the experimental sites. The overall results demonstrate that all the test units show proper range for vegetation. 2. We believe that the physical properties of soils in the earlier phase of restoration works on the sloped sites are not greatly affected by the fact whether broken chips exist or not. However, as time elapses, broken chips needs to be investigated further on what kind of impact they have on the soil condition. 3. More species are found in the test unit combining broken chips and we believe that it will contribute to blossoming of green plants and ecological succession of neighboring plants. 4. We performed experiment on possibility for fresh root-chips as substitutes for the hydro-seeding soil-media. In the test unit that combines fresh root-chips, its mixture ratio tends to exceed that of the test unit that does not combine fresh root-chips by 5 %. In case of the Thick-Layer-Soil-Media Hydroseeding works, the mixture ratio of the test unit that combines fresh root-chips after 16 weeks exceeds that of the test unit that does not combine fresh root-chips by 75%. 5. From the result of our experiment, it is obvious that the ratio of mixture and the number of emerging species are higher for the test unit combining fresh root-chips than the test unit that does not combine them. In other words, we can replace the hydro-seeding-soil-media with some Fresh root-chips without affecting the physical property of soil.

• Geomechanics and Engineering
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• 제13권2호
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• pp.333-352
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• 2017

A comparison study is made between the dynamic properties of an argillaceous siltstone and its grouting-reinforced body. The purpose is to investigate how grout injection can help repair broken soft rocks. A slightly weathered argillaceous siltstone is selected, and part of the siltstone is mechanically crushed and cemented with Portland cement to simulate the grouting-reinforced body. Core specimens with the size of $50mm{\times}38mm$ are prepared from the original rock and the grouting-reinforced body. Impact tests on these samples are then carried out using a Split Hopkinson Pressure Bar (SHPB) apparatus. Failure patterns are analyzed and geotechnical parameters of the specimens are estimated. Based on the experimental results, for the grouting-reinforced body, its shock resistance is poorer than that of the original rock, and most cracks happen in the cementation boundaries between the cement mortar and the original rock particles. It was observed that the grouting-reinforced body ends up with more fragmented residues, most of them have larger fractal dimensions, and its dynamic strength is generally lower. The mass ratio of broken rocks to cement has a significant effect on its dynamic properties and there is an optimal ratio that the maximum dynamic peak strength can be achieved. The dynamic strain-softening behavior of the grouting-reinforced body is more significant compared with that of the original rock. Both the time dependent damage model and the modified overstress damage model are equally applicable to the original rock, but the former performs much better compared with the latter for the grouting-reinforced body. In addition, it was also shown that water content and impact velocity both have significant effect on dynamic properties of the original rock and its grouting-reinforced body. Higher water content leads to more small broken rock pieces, larger fractal dimensions, lower dynamic peak strength and smaller elastic modulus. However, the water content plays a minor role in fractal dimensions when the impact velocity is beyond a certain value. Higher impact loading rate leads to higher degree of fragmentation and larger fractal dimensions both in argillaceous siltstone and its grouting-reinforced body. These results provide a sound basis for the quantitative evaluation on how cement grouting can contribute to the repair of broken soft rocks.

• 한국식품과학회지
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• 제34권2호
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• pp.220-224
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• 2002

폐기물로 버려지는 명태 가공부산물인 절란을 효율적으로 이용할 수 있는 방안을 찾기 위해, 절란 젓을 제조하여 cellulose casing에 포장한 다음 숙성 중에 일어나는 여러 가지 화학적 및 미생물 변화를 측정하였다. 상온숙성$(25^{\circ}C)$에서는 냉장숙성$(5^{\circ}C)$보다 pH가 급격히 감소하는 것으로 나타났으며, 젖산량은 숙성이 진행됨에 따라 상온숙성에서는 급격한 증가를 보였고 냉장숙성에서는 서서히 증가하였다. 아미노태 질소는 상온숙성시 숙성기간 1주일째 급격한 증가 후 서서히 증가하였고 냉장숙성$(5^{\circ}C)$시 3주째까지 증가하다가 감소하였다. 휘발성 염기성 질소는 상온숙성$(25^{\circ}C)$시 급격한 증가를 보였고, 냉장숙성$(5^{\circ}C)$시 서서히 증가함을 보였다. 미생물의 변화는 상온숙성$(25^{\circ}C)$시 냉장숙성$(5^{\circ}C)$보다 미생물의 수치가 높았으며, 대장균군은 초기에 나타났다가 모두 제거되었다. 명태 절란젓의 최적 생산공정 및 유통기간 설정을 위해서는 관능검사 등을 통한 보충연구가 필요하다고 본다.

• 한국가금학회지
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• 제19권4호
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• pp.177-185
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• 1992

본 연구는 대한양계협회에서 1985년부터 1991년까지 7회에 걸쳐 실시한 산난계 경제능력 검정성적을 기초로 하여 유색산난계의 연파난 발생비율과 다른 형질간의 년차별 평균능력의 변화와 연파난 발생비율이 다른 형질들에 의해 변화되는 정도를 추정하여 상관계수를 구하여 산난계의 연파난 발생비율을 감소시킬 수 있는 산란계 개량 방향과 사양관리조건 개선에 대한 기초 자료를 제시하기 위하여 실시한 것으로 그 결과를 요약하면 다음과 같다. 1. 유색산난계의 18∼72주령 초산일령은 163.6일, 산난율은 79.49％, 산난지수는 272.9개, 난중은 62.69g이었으며, 연파난 발생비율은 1.141％이었고 백색산난계는 18∼72주령에 각 형질의 평균능력이 각각 157.2일, 77.87％, 265.1개, 60.26g이었으며 연파난 발생비율은 1.174％이었다. 2. 유색산난계의 18∼72주령과 18∼78주령에 조사된 각 형질의 능력에 대한 유의성 검정결과 생존율, 초산일령, 산난율, 사료요구율, 체중 및 연파난 발생비율은 고도의 통계적 유의성(P＜0.01)이 인정되었다. 3. 유색산난계의 '85∼'91년 기간중 18∼72주령에는 초산일령은 168.5일에서 155.9일로 단축되었고 연파난 발생비율은 1.4∼l.69％에서 0.89∼0.94％로 감소하였으며, 18∼78주령에는 산난율은 74.5∼75.1％에서 77.8∼80.6％로 증가하였고, 산난지수는 302.0∼304.6개로 증가하였고, 연파난율은 1.54∼2.02％에서 0.98％ 내외로 감소하는 경향을 나타냈다. 4. 유색산난계에 대한 각 형질의 능력에 따른 21∼72주령의 연파난 발생비율과의 상관계수는 초산일령 0.3985, 난중 0.1072, 72주령 체중은 0.4225로 정의 상관을 나타냈으며, 산난율은 -0.5662, 산난지수는 -0.2896, 그리고 사료요구율과는 -0.245로 부의 상관을 나타냈다. 5. 유색산난계의 21∼78주령 각 형질의 능력에 따른 연파난 발생비율과의 상관계수는 초산 일령 0.3971, 난중 0.1171 그리고 78주령 체중은 0.4609의 정의 상관을 나타냈고, 산난율은 -0.5041, 산난지수는 -0.2372 그리고 사료요구율은 -0.2421로 부의 상관을 나타냈다.

• 한국수자원학회:학술대회논문집
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• 한국수자원학회 2003년도 학술발표회논문집(2)
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• pp.627-630
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• 2003

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.3512-3517
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• 2007

Nuclear power plant has many external fire hydrants that have to operate in the state of emergency such as facility fire, forest fire. The valve stem of one among them was broken 3 times for 4 years. It had long valve stem and operated under high water pressure. The elongation and the tensile strength for the broken valve stem was measured to examine the defect of material property. And the vibration level and the natural frequencies was detected to check the resonance. As the result of a diagnosis, the cause of this fault is proven buckling of long valve stem.

• International Journal of Contents
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• 제8권2호
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• pp.89-96
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• 2012

Scientific analysis of crime hot spots is essential in preventing and/or suppressing crime. However, results could be different depending on the analytic methods, which highlights the importance of choosing adequate tools. The purpose of this study was to introduce two advanced techniques for detecting crime hot spots, GAM and Local Moran's I, hoping for more police agencies to adopt better techniques.GAM controls for the number of population in study regions, but local Moran's I does not. That is, GAM detects high crime rate areas, whereas local Moran's I identifies high crime volume areas. For GAM, physical disorder was used as a proxy measure for population at risk based on the logic of the broken windows theory. Different regions were identified as hot spots. Although GAM is generally regarded as a more advanced method in that it controls for population, it's usage is limited to only point data. Local Moran's I is adequate for zonal data, but suffers from the unavoidable MAUP(Modifiable Areal Unit Problem).

• 한국철도학회:학술대회논문집
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• 한국철도학회 2011년도 춘계학술대회 논문집
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• pp.1399-1406
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• 2011

As a result of the examination analyzed loop type of Detecting the Broken Rail Monitoring System as a part of prevention of train derailment, installed in the Seoul Metro No. 2 subway line 98.51m section which is Samsung to Seolleung, we found that it is possible to detect crack location(Thermit welding: 48.18m) within the margin of error of ${\pm}1m$ accurately As analysis of the first day, third day, fifty day, and seventh day periodically, we found that Fresnel reflection happened where the crack location 48.18m. However other 3 branches show loss by bending of optical cable(spread reflection from the outside impact).

• 한국경영과학회지
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• 제42권3호
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• pp.13-24
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• 2017

This paper aims to implement "structural changes detection procedure" in pairs trading algorithm and to show that the proposed approach outperforms the extant pair trading algorithm. Structural changes in pairs trading are defined in terms of changes in cointegrating factors and broken cointegration relationship. These changes are designed to test extant structural changes and unit root test methodologies. The simulation finds that expanding the changes in structure, increasing the mean reverting process of spread, and extending the consecutive days of broken cointegration will increase the performances of the proposed algorithm. Empirical study results are also consistent those of the simulation studies. The proposed algorithm outperforms the extant algorithm relative to risk and return given that the cumulative profit/loss has a significant upward-slope with minimal variance.

• Journal of Magnetics
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• 제15권2호
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• pp.91-98
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• 2010

The paper presents results of a study on the selective separation technology of ferrous and non-ferrous metals from broken light bulbs. The proposed method is to use magnetic fluids to obtain a magnetic fluid based- separation. [1] The study was conducted using three types of waste materials: regular light bulbs, auto light bulbs and neon tubes. In order to process the waste materials, a six stages technologic flow was developed: a) separation of light bulbs components; b) Physical and chemical analysis of raw materials; c) grain conditioning of the raw material; d) dry magnetic separation of ferrous components; e) magnetic fluid separation of non-magnetic material; f) recovery of the magnetic fluid adhered to the surface of the separated material grains. [2] This study shows that magnetic fluid separation is only profitable for regular and auto light bulbs and is not profitable in the case of neon tubes.