• Title/Summary/Keyword: erosion equation

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Derivation of Empirical Method to Enhance the Accuracy of Cannon Tube Erosion Rate (포신 마모 예측의 정확도 향상을 위한 실험적 방법 유도)

  • 정동윤;오명호
    • Journal of the Korea Institute of Military Science and Technology
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    • v.5 no.3
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    • pp.23-32
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    • 2002
  • We predict the erosion rate of unknown cannon tubes by substituting measured values of the standard cannon, 155㎜ Howitzer M185 and ballistic data for the erosion equation. We know ten measured erosion values of the standard cannon at every 400 rounds. An approximate formula is derived to interpolate six values up to 2,000 rounds. Numerical example is presented and its results are analyzed. The new erosion equation is also suggested. This equation produces more accurate cannon tube erosion rate than the Rauf Imam's empirical approaches. Computer simulations are presented.

Remote Sensing Information Models for Sediment and Soil

  • Ma, Ainai
    • Proceedings of the KSRS Conference
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    • 2002.10a
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    • pp.739-744
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    • 2002
  • Recently we have discovered that sediments should be separated from lithosphere, and soil should be separated from biosphere, both sediment and soil will be mixed sediments-soil-sphere (Seso-sphere), which is using particulate mechanics to be solved. Erosion and sediment both are moving by particulate matter with water or wind. But ancient sediments will be erosion same to soil. Nowadays, real soil has already reduced much more. Many places have only remained sediments that have ploughed artificial farming layer. Thus it means sediments-soil-sphere. This paper discusses sediments-soil-sphere erosion modeling. In fact sediments-soil-sphere erosion is including water erosion, wind erosion, melt-water erosion, gravitational water erosion, and mixed erosion. We have established geographical remote sensing information modeling (RSIM) for different erosion that was using remote sensing digital images with geographical ground truth water stations and meteorological observatories data by remote sensing digital images processing and geographical information system (GIS). All of those RSIM will be a geographical multidimensional gray non-linear equation using mathematics equation (non-dimension analysis) and mathematics statistics. The mixed erosion equation is more complex that is a geographical polynomial gray non-linear equation that must use time-space fuzzy condition equations to be solved. RSIM is digital image modeling that has separated physical factors and geographical parameters. There are a lot of geographical analogous criterions that are non-dimensional factor groups. The geographical RSIM could be automatic to change them analogous criterions to be fixed difference scale maps. For example, if smaller scale maps (1:1000 000) that then will be one or two analogous criterions and if larger scale map (1:10 000) that then will be four or five analogous criterions. And the geographical parameters that are including coefficient and indexes will change too with images. The geographical RSIM has higher precision more than mathematics modeling even mathematical equation or mathematical statistics modeling.

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An overview of applicability of WEQ, RWEQ, and WEPS models for prediction of wind erosion in lands

  • Seo, Il Whan;Lim, Chul Soon;Yang, Jae Eui;Lee, Sang Pil;Lee, Dong Sung;Jung, Hyun Gyu;Lee, Kyo Suk;Chung, Doug Young
    • Korean Journal of Agricultural Science
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    • v.47 no.2
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    • pp.381-394
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    • 2020
  • Accelerated soil wind erosion still remains to date to cause severe economic and environmental impacts. Revised and updated models to quantitatively evaluate wind induced soil erosion have been made for specific factors in the wind erosion equation (WEQ) framework. Because of increasing quantities of accumulated data, the WEQ, the revised wind erosion equation (RWEQ), the wind erosion prediction system (WEPS), and other soil wind erosion models have been established. These soil wind erosion models provide essential knowledge about where and when wind erosion occurs although naturally, they are less accurate than the field-scale. The WEQ was a good empirical model for comparing the effects of various management practices on potential erosion before the RWEQ and the WEPS showed more realistic estimates of erosion using easily measured local soil and climatic variables as inputs. The significant relationship between the observed and predicted transport capacity and soil loss makes the RWEQ a suitable tool for a large scale prediction of the wind erosion potential. WEPS developed to replace the empirical WEQ can calculate soil loss on a daily basis, provide capability to handle nonuniform areas, and obtain predictions for specific areas of interest. However, the challenge of precisely estimating wind erosion at a specific regional scale still remains to date.

New Empirical Approach to Enhance The Accuracy of Cannon Tube Erosion Rate

  • Chung, Dong-Yoon;Oh, Myoung-Ho
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.10b
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    • pp.231-232
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    • 2002
  • Various methods that utilize erosion rate measurement of standard cannon, 155mm Howitzer M185, as reference, are being used to calculate erosion rate of an interested unknown cannon tubes. We know ten measured erosion values of the standard cannon from 391 rounds to 4.000. An approximate function fitting these value s is derived. The new erosion equation is also suggested and computer simulations arc presented.

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Derivation of Empirical Erosion Equation of the 40 mm Long Hollow Cylinder (40 mm 장축공동실린더의 마모경험식 유도)

  • Chung, Dong-Yoon;Oh, Myoung-Ho;Shin, Nae-Ho
    • Tribology and Lubricants
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    • v.25 no.3
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    • pp.171-175
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    • 2009
  • One of the critical issues associated with the 40mm long hollow cylinder's development and maintenance is the prediction of cylinder erosion. The actual firing test is the most accurate method to measure the cylinder erosion rate. But it costs a great deal and requires a long measurement time. Hence many empirical methods have been proposed to predict the erosion rate and life span of long hollow cylinders. An EFC formula is calculated. An approximate erosion formula for the ammunition type A is derived to interpolate 16 observation values up to 4,000 rounds. A new erosion equation and muzzle velocity formula are also suggested. Several numerical results are presented.

The Theoretical Analyses of the Soil Erosion and Conservation 3. Analytical Theory of Slope Erosion (토양의 침식과 보존에 관한 이론적 분석 3. 사면 토양의 침식에 관한 이론)

  • 장남기
    • Asian Journal of Turfgrass Science
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    • v.10 no.1
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    • pp.41-47
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    • 1996
  • The theory of slope erosion is developed along similar lines to the theory of heat flow in solid added to the correcting factor. if slope erosion in the forest and grassland proceeds according to the hypothesis, it is $\delta$y $\delta^2$y = k $\delta^2$y $\delta$$X^2$+f(s b. t) where 5 is internal properties of slope soil and b is biota on slope. When the variables of the equation of slope erosion are x = -λ the initial elevation=-f(λ), x=λ, x==a, the steady value of the initial elevation=y, and dy dx x=0> =O(t>o), respectively, the houndary condition due to the solution of the equation of slope erosion is y= 2 √$\pi$kt [∫a o λe $(X-λ)^2$4kt dλ- ∫ao- $(x+λ)^2$4kt dλ] + ∫∫∫ f (s.b. t)dtdbds

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Integration of GIS with USLE in Assessment of Soil Erosion due to Typoon Rusa (태풍 루사에 의한 토양 침식량 산정을 위한 GIS와 범용토양손실공식(USLE) 연계)

  • Hahm, Chang-Hahk;Kim, Byung-Sik
    • Journal of Korean Society for Geospatial Information Science
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    • v.15 no.3
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    • pp.77-85
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    • 2007
  • Assessment of soil erosion is a cost and time-consuming task. There are many models developed to predict soil erosion from an area, but Universal Soil Loss Equation (USLE) is most widely used empirical equation for estimating annual soil erosion. Soil erosion depends upon-rainfall intensity, type of soil, land cover and land use, slope degree, slope length and soil conservation practice. All these parameters are have spatial distribution and hence satellite remote sensing and Geographic Information System (GIS) are applicable in the assessment of the influence on soil erosion. GIS has been integrated with the USLE (Universal Soil Loss Equation) model in identification of rainfall-based erosion to the Bocheong River which is the representative basin of IHP due to Typhoon Rusa. Similar studies are available in literature, ranging from those that use a simple model such as USLE to others of a more sophisticated nature.

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An Experimental Investigation of Particle Impingement Erosion in Hydraulic Systems (유압시스템의 입자 침해 침식의 실험적 고찰)

  • 이재천;김성훈
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.2
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    • pp.117-122
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    • 2002
  • This study assesses the wear process of particle impingement erosion which is a major source of erosion among fluid power components. First, Bitter's theory was modified to simplify engineering calculations. Second, actual experiments were conducted to validate the modified equation. And the effect of concentration and size distribution of impinging particles was tested. Little deviation from the prediction of the modified equation was observed. To develop complete analytical approach to the erosion mechanism, further experimental data are required to establish a correlation with other engineering parameters.

An Experimental Investigation of Particle Impingement Erosion in Hydraulic System (유압시스템의 입자 침해 침식의 실험적 고찰)

  • 이재천
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2001.06a
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    • pp.15-21
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    • 2001
  • This study assesses the wear process of particle impingement erosion which is a major source of erosion among fluid power components. First, Bitter's theory was modified to simplify engineering calculations. Second, actual experiments were conducted to validate the modified equation. And the effect of concentration and size distribution of impinging particles was tested. Little deviation from the prediction of the modified equation was observed. To develop an analytical approach to the erosion mechanism, further experimental data are required to establish a correlation with other engineering parameters.

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Derivation of Fitting Approximate Formula to Enhance the Accuracy of Cannon Tube Erosion Rate (포신 마모 예측의 정확도 향상을 위한 적합 근사식 유도(I))

  • Chung, Dong-Yoon;Oh, Myoung-Ho
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 2002.05a
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    • pp.80-87
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    • 2002
  • We predict the unknown cannon tube erosion rate by using observed values of the standard cannon, 155mm Howitzer Ml85. We know the standard cannon's ten erosion observation values each 400 rounds. An approximate formula fitting the erosion values of the standard cannon has been derived. Numerical simulation applying this formula to the Rauf Imam's erosion equations is presented.

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