• Title/Summary/Keyword: bulk input

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Quantification of Soil Properties using Visible-NearInfrared Reflectance Spectroscopy (가시·근적외 분광 스펙트럼을 이용한 토양 이화학성 추정)

  • Choe, Eunyoung;Hong, S. Young;Kim, Yi-Hyun;Song, Kwan-Cheol;Zhang, Yong-Seon
    • Korean Journal of Soil Science and Fertilizer
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    • v.42 no.6
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    • pp.522-528
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    • 2009
  • This study focused on establishing prediction models using visible-near infrared spectrum to simultaneously detect multiple components of soils and enhancing the performance quality by suitably transformed input spectra and classification of soil spectral types for prediction model input. The continuum-removed spectra showed significant result for all cases in terms of soil properties and classified or bulk predictions. The prediction model using classified soil spectra at an absorption peak area around 500nm and 950nm efficiently indicating soil color showed slightly better performance. Especially, Ca and CEC were well estimated by the classified prediction model at $R^{2}$ > 0.8. For organic carbon, both classified and bulk prediction model had a good performance with $R^{2}$ > 0.8 and RPD> 2. This prediction model may be applied in global soil mapping, soil classification, and remote sensing data analysis.

Effects of Moisture Content on Physical Properties of Extruded Cereal Flours (수분함량에 따른 곡류 압출성형물의 물리적 특성 비교)

  • Kim, Cheol-Hyun;Jin, Tie;Ryu, Gi-Hyung
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.41 no.11
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    • pp.1603-1610
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    • 2012
  • The effects of moisture content on the physical properties of cereal extrudates were investigated. Cereal flours (rice, wheat, corn, barley, and oat) were extruded at a barrel temperature of $130^{\circ}C$, feed rate of 120 g/min, and various moisture contents (20, 22.5, 25, 27.5, and 30%). Proximate content, expansion index, specific length, bulk density, breaking strength, apparent elastic modulus, water absorption index (WAI), water solubility index (WSI), specific mechanical energy (SME) input, paste viscosity, and color values were analyzed. Expansion ratio of extruded corn flour was higher than that of other extrudates at low moisture content. Bulk density, specific length, and elastic modulus in all cereals decreased with an increase in moisture content. The WAI increased with an increase in moisture content, whereas WSI decreased. SME input of extruded corn flour was higher than those of other cereal flours at lower moisture content, whereas that of oat flour extrudate was lower than those of other cereals at higher moisture content. Lightness of extruded rice flour was lighter than those of other cereals while that of extruded barley flour was darker.

Properties of artificial aggregates fabricated with various heating conditions (다양한 승온조건으로 제조된 인공골재의 특성)

  • Kim, Kang-Duk;Kang, Seung-Gu
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.20 no.6
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    • pp.301-306
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    • 2010
  • The artificial aggregates were fabricated by using the inorganic wastes, dredged soil produced at a dredging work. The input temperature ($800{\sim}1000^{\circ}C$), output temperature ($1100{\sim}1200^{\circ}C$) and heating rate ($5{\sim}10^{\circ}C$/min) in sintering process were controlled to fabricate the aggregates with various value of density and water absorption, and their properties were analyzed as a function of those factors. The specimens sintered at the lower input temperature showed the higher density and the lower water absorption while those with higher input temperature had many pores inside of the aggregates, lower density and higher water absorption. Also increasing the input temperature accelerated the black core phenomenon in the aggregates. The bloating phenomena which the gigantic pores were generated inside the aggregates were improved as increasing the output temperature, but its effect was lower than that of input temperature. It could be realized that the bloating tendency was improved from the results that the density was increased and water absorption was decreased with increasing heating rate from 5 to $10^{\circ}C$/min. It was found that the artificial aggregates of light or heavy weight with various value of density and water absorption could be fabricated by using dredged soils naturally involving gas and fluxing components by controlling the sintering conditions.

Heat treatment characteristics of medium carbon steel by CW Nd:YAG Laser (CW Nd:YAG 레이저를 이용한 중탄소강의 열처리특성)

  • Shin H.J.;Yoo Y.T.;Ahn D.G.;Im K.
    • Proceedings of the Korean Society of Precision Engineering Conference
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    • 2005.06a
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    • pp.438-443
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    • 2005
  • Laser surface hardening is an effective technique used to improve the tribological properties and also to increase the service life of automobile components such as camshafts, crankshatfs, lorry brake drums and gears. High power CO2 lasers and Nd:YAG lasers are employed for localized hardening of materials and hence are of potential application in the automobile industries. The heat is conducted rapidly into the bulk of the specimen causing self-quenching to occur and the formation of martensitic structure. In this investigation, the microstructure features occurring in Nd:YAG laser hardening SM45C steel are discussed with the use of optical microscopic and scanning electron microscopic analysis. Moreover, This paper describes the optimism of the processing parameters for maximum hardened depth of SM45C steel specimens of 3mm thickness by using CW Nd:YAG laser. Travel speed was varied from 0.6m/min to 1.0m/min. The maximum hardness and case depth fo SM45C steel are 780Hv and 0.4mm by laser hardening.

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Fabrication of a Magnetostrictive Transpositioner using Thin Film Deposition and MEMS Techniques (박막성형 기술 및 MEMS 공정을 이용한 자기변형 위치변환기)

  • Lee, Heung-Shik;Cho, Chong-Du;Lee, Sang-Kyo
    • Proceedings of the KSME Conference
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    • 2007.05a
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    • pp.1617-1620
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    • 2007
  • This paper presents a magnetostrictive transpositioner and its fabrication process. To get a transposition movement without shifting or twisting, it is designed as an array type. To fabricate the suggested design, micromachining and selective DC magnetron sputtering processes are combined. TbDyFe film is sputter-deposited on the back side of the bulk micromachined transpositioner, with the condition as: Ar gas pressure below $1.2{\times}10^{-9}$ torr, DC input power of 180W and heating temperature of up to $250^{\circ}C$ for the wireless control of each array component. After the sputter process, magnetization and magnetostriction of each sample are measured. X-ray diffraction studies are also carried out to determine the film structure and thickness of the sputtered film. For the operation, each component of the actuator has same length and out-of-plane motion. Each component is actuated by externally applied magnetic fields up to 0.5T and motion of the device made upward movement. As a result, deflections of the device due to the movement for the external magnetic fields are observed.

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Feedback Control for Expanding Range and Improving Lineraity of Microaccelerometers (가속도계의 동작범위 확장와 선형성 향상을 위한 피드백 제어)

  • Park, Yong-Hwa;Park, Sang-Jun;Choi, Byung-Doo;Ko, Hyoung-Ho;Song, Tae-Yong;Lim, Genu-Won;Huh, Kun-Soo;Park, Jahng-Hyon;Cho, Dong-il
    • Journal of Institute of Control, Robotics and Systems
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    • v.10 no.11
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    • pp.1082-1088
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    • 2004
  • This paer presents a feedback-controlled, MEMS-fabricated microaccelerometer($\mu$XL). The $\mu$XL has received much commercial attraction, but its performance is generally limited. To improve the open-loop performance, a feedback controller is designed and experimentally evaluated. The feedback controller is applied to the x/y-axis $\mu$XL fabricated by sacrificial bulk micromachining(SBM) process. Even though the resolution of the closed-loop system is slightly worse than open-loop system, the bandwidth, linearity, and bias stability are stability are significantly improved. The noise equivalent resolution of open-loop system is 0.615 mg and that of closed-loop system is 0.864 mg. The bandwidths of open-loop and closed-loop system are over 100Hz. The input range, non-linearity and bias stability are improved from $\pm10\;g\;to\;\pm18g$, from 11.1%FSO to 0.86%FSO, and from 0.221 mg to 0.128 mg by feedback control, respectively.

Analysis of temperature effects on DC parameters of AlGaAs/GaAs HBT (AlGaAs/GaAs HBT의 DC 파라미터에 미치는 온도영향의 해석)

  • 김득영;박재홍;송정근
    • Journal of the Korean Institute of Telematics and Electronics A
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    • v.33A no.12
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    • pp.39-46
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    • 1996
  • In AlGaAs/GaAs HBT the temperature dependence of DC parameters was investigated over the temperature range between 95K and 580K. The temperature dependence of DC parameters depends on the relative contribution of each of the current components suc as emitter-injection-current, base-injection-current, bulk recombination current, interface recombination curretn, thermal generation ecurrent and avalanche current due to impact ionization within the collector space charge layer in a specific temperature. In this paper we investigated the temperature effects on DC parameters such as V$_{BE,ON}$ current gain, input and output characteristics, V$_{CE, OFF}$, R$_{E}$, R$_{C}$ and analyzed the origins, and extracted the qualitativ econditions for a stable HBTs against the temperature variation. Finally, in order to keep HBTs stable with respect to the variation of temperature, the valance-band-energy-discontinuity at emitter-base heterojunction should be large enough to enhance the effect of carrier suppression at a relatively high temperature. In addition the recombination centers, especially around collector junction, should be removed and the area of emitter and collector junction should be identical as well.

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An Analysis of Railroad Trackbed Behavior under Train Wheel Loads (열차 하중에 의한 철도노반의 거동 분석)

  • Park, Chul-Soo;Choi, Chan-Yong;Choi, Chung-Lak;Mok, Young-Jin
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.587-598
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    • 2008
  • In the trackbed design using elastic multi-layer model, the stress-dependent resilient modulus is an important input parameter, which reflects substructure performance under repeated traffic loading. The resilient moduli of crushed stone and weathered granite soil were developed using nonlinear dynamic stiffness, which can be measured by in-situ and laboratory seismic tests. The prediction models of resilient modulus varying with the deviatoric or bulk stress were proposed (Park et al., 2008). To investigate the performance of the prediction models proposed herein, the elastic response of the test trackbed near PyeongTaek, Korea was evaluated using a 3-D nonlinear elastic computer program (GEOTRACK) and compared with measured elastic vertical displacement during the passages of freight and passenger trains. The material types of the test sub-ballasts are crushed stone and weathered granite soil, respectively. The calculated vertical displacements within the sub-ballasts are within the order of 1mm, and agree well with measured values with the reasonable margin. The prediction models are thus concluded to work properly in the preliminary investigation. The prediction models proposed for resilient modulus were verified by the comparison of the calculated vertical displacements with measured ones during train passages.

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Study on the Static and Dynamic Structural Analysis Procedure of Excavators (굴삭기의 정적/동적 강도 해석법에 대한 연구)

  • Choung, Joon-Mo;Kim, Gyu-Sung;Jang, Young-Sik;Choe, Ick-Hung;Heo, Min-Soo
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.537-543
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    • 2003
  • This paper presents the improved procedure to assess static and dynamic strength of crawler type excavators. A fully integrated model including front attachment and chassis was prepared for structural analysis. In this paper, two types of loading input methods were investigated and the method imposing digging force directly on bucket tooth was more convenient than imposing cylinder reaction force on cylinder pin even if the two methods showed no discrepancy in analysis results. Static strength analysis was carried out for eight analysis scenarios based on two extreme digging positions, maximum digging reach position and maximum digging force positions. The results from static strength analysis were compared with measured stresses, cylinder pressures and digging forces and showed a good quantitative agreement with measured data. Dynamic strength analysis was carried out for simple reciprocation of boom cylinders. It was recognized that the effect of compressive stiffness of hydraulic oil was very important for dynamic structural behavior. The results from dynamic strength analysis including hydraulic oil stiffness were also compared with measured acceleration data and showed a qualitative agreement with measured data.

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An Analysis of Railroad Trackbed Behavior Using Resilient Modulus Prediction Models (회복탄성계수 예측모델을 이용한 철도노반의 거동 분석)

  • Park, Chul-Soo;Jung, Jae-Woo;Oh, Sang-Hoon;Kim, Eun-Jung;Mok, Young-Jin
    • Proceedings of the KSR Conference
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    • 2008.06a
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    • pp.1712-1723
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    • 2008
  • In the trackbed design using an elastic multi-layer model, the stress-dependent resilient modulus is the key input parameter, which reflects substructure performance under repeated traffic loading. The prediction models of resilient modulus of crushed stone and weathered granite soil were developed from nonlinear dynamic stiffness, which can be combined by in-situ and laboratory seismic measurements. The models accommodate the variation with the deviatoric and/or bulk stresses. To investigate the performance of the prediction models proposed, the elastic response of the test trackbed near PyeongTaek, Korea was evaluated using a 3-D nonlinear elastic computer program (GEOTRACK) and compared with measured elastic vertical displacement caused by the passages of freight and passenger trains. The material types of the test sub-ballasts are crushed stone and weathered granite soil, respectively. The calculated vertical displacements within the sub-ballasts are within the order of 1mm, and agree well with measured values with the reasonable margin. The prediction models are thus concluded to work properly in the preliminary investigation.

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