• Title/Summary/Keyword: Support radius

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Modelling Pasture-based Automatic Milking System Herds: Grazeable Forage Options

  • Islam, M.R.;Garcia, S.C.;Clark, C.E.F.;Kerrisk, K.L.
    • Asian-Australasian Journal of Animal Sciences
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    • v.28 no.5
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    • pp.703-715
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    • 2015
  • One of the challenges to increase milk production in a large pasture-based herd with an automatic milking system (AMS) is to grow forages within a 1- km radius, as increases in walking distance increases milking interval and reduces yield. The main objective of this study was to explore sustainable forage option technologies that can supply high amount of grazeable forages for AMS herds using the Agricultural Production Systems Simulator (APSIM) model. Three different basic simulation scenarios (with irrigation) were carried out using forage crops (namely maize, soybean and sorghum) for the spring-summer period. Subsequent crops in the three scenarios were forage rape over-sown with ryegrass. Each individual simulation was run using actual climatic records for the period from 1900 to 2010. Simulated highest forage yields in maize, soybean and sorghum- (each followed by forage rape-ryegrass) based rotations were 28.2, 22.9, and 19.3 t dry matter/ha, respectively. The simulations suggested that the irrigation requirement could increase by up to 18%, 16%, and 17% respectively in those rotations in El-Nino years compared to neutral years. On the other hand, irrigation requirement could increase by up to 25%, 23%, and 32% in maize, soybean and sorghum based rotations in El-Nino years compared to La-Nina years. However, irrigation requirement could decrease by up to 8%, 7%, and 13% in maize, soybean and sorghum based rotations in La-Nina years compared to neutral years. The major implication of this study is that APSIM models have potentials in devising preferred forage options to maximise grazeable forage yield which may create the opportunity to grow more forage in small areas around the AMS which in turn will minimise walking distance and milking interval and thus increase milk production. Our analyses also suggest that simulation analysis may provide decision support during climatic uncertainty.

Thermo-Sensitive Polyurethane Membrane with Controllable Water Vapor Permeation for Food Packaging

  • Zhou, Hu;Shit, Huanhuan;Fan, Haojun;Zhou, Jian;Yuan, Jixin
    • Macromolecular Research
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    • v.17 no.7
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    • pp.528-532
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    • 2009
  • The size and shape of free volume (FV) holes available in membrane materials control the rate of gas diffusion and its permeability. Based on this principle, a segmented, thermo-sensitive polyurethane (TSPU) membrane with functional gate, i.e., the ability to sense and respond to external thermo-stimuli, was synthesized. This smart membrane exhibited close-open characteristics to the size of the FV hole and water vapor permeation and thus can be used as smart food packaging materials. Differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), positron annihilation lifetimes (PAL) and water vapor permeability (WVP) were used to evaluate how the morphological structure of TSPU and the temperature influence the FV holes size. In DSC and DMA studies, TSPU with a crystalline transition reversible phase showed an obvious phase-separated structure and a phase transition temperature at $53^{\circ}C$ (defined as the switch temperature and used as a functional gate). Moreover, the switch temperature ($T_s$) and the thermal-sensitivity of TSPU remained available after two or three thermal cyclic processes. The PAL study indicated that the FV hole size of TSPU is closely related to the $T_s$. When the temperature varied cyclically from $T_s-10{\circ}C$ to $T_s+10^{\circ}C$, the average radius (R) of the FV holes of the TSPU membrane also shifted cyclically from 0.23 to 0.467 nm, exhibiting an "open-close" feature. As a result, the WVP of the TSPU membrane also shifted cyclically from 4.30 to $8.58\;kg/m^2{\cdot}d$, which produced an "increase-decrease" response to the thermo-stimuli. This phase transition accompanying significant changes in the FV hole size and WVP can be used to develop "smart materials" with functional gates and controllable water vapor permeation, which support the possible applications of TSPU for food packaging.

Collaborative Beamforming for Ad Hoc Sensor Networks (분산된 Ad Hoc 센서 네트워크의 협력 빔포밍)

  • Yang, Mi-Sun;Kim, Jung-Bin;Kim, Dong-Woo
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.34 no.1A
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    • pp.34-40
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    • 2009
  • In this paper, we derive the average received beampattern at each receive node which is randomly distributed within a disk when considering a collaborative beanforming between transmission nodes which are randomly distributed within another disk for ad hoc sensor network. Numerical results show that the radius of disk at the transmitter determines the beamwidth of mainbeam, and the sidebeam is affected by the number of transmitter nodes. We also consider K receive groups and divide the transmit sensor modes into K groups to support each receive group using beamforming, and derive the SINR at each receive node. Finally, we investigate the effects of beampattern and interference on total sum capacity among all receive node, and numerically determine the number of transmit nodes for each group which can achieve the maximal sum capacity.

ROAD CROWN, TIRE, AND SUSPENSION EFFECTS ON VEHICLE STRAIGHT-AHEAD MOTION

  • LEE J-H.;LEE J. W.;SUNG I. C.
    • International Journal of Automotive Technology
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    • v.6 no.2
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    • pp.183-190
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    • 2005
  • During normal operating conditions, a motor vehicle is constantly subjected to a variety of forces, which can adversely affect its straight-ahead motion performance. These forces can originate both from external sources such as wind and road and from on-board sources such as tires, suspension, and chassis configuration. One of the effects of these disturbances is the phenomenon of vehicle lateral-drift during straight-ahead motion. This paper examines the effects of road crown, tires, and suspension on vehicle straight-ahead motion. The results of experimental studies into the effects of these on-board and external disturbances are extremely sensitive to small changes in test conditions and are therefore difficult to guarantee repeatability. This study was therefore conducted by means of computer simulation using a full vehicle model. The purpose of this paper is to gain further understanding of the straight-ahead maneuver from simulation results, some aspects of which may not be obtainable from experimental study. This paper also aims to clarify some of the disputable arguments on the theories of vehicle straight-ahead motion found in the literature. Tire residual aligning torque, road crown angle, scrub radius and caster angle in suspension geometry, were selected as the study variables. The effects of these variables on straight-ahead motion were evaluated from the straight-ahead motion simulation results during a 100m run in free control mode. Examination of vehicle behavior during straight-ahead motion under a fixed control mode was also carried out in order to evaluate the validity of several disputable arguments on vehicle pull theory, found in the literature. Finally, qualitative comparisons between the simulation results and the test results were made to support the validity of the simulation results.

A Circle Labeling Scheme without Re-labeling for Dynamically Updatable XML Data (동적으로 갱신가능한 XML 데이터에서 레이블 재작성하지 않는 원형 레이블링 방법)

  • Kim, Jin-Young;Park, Seog
    • Journal of KIISE:Databases
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    • v.36 no.2
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    • pp.150-167
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    • 2009
  • XML has become the new standard for storing, exchanging, and publishing of data over both the internet and the ubiquitous data stream environment. As demand for efficiency in handling XML document grows, labeling scheme has become an important topic in data storage. Recently proposed labeling schemes reflect the dynamic XML environment, which itself provides motivation for the discovery of an efficient labeling scheme. However, previous proposed labeling schemes have several problems: 1) An insertion of a new node into the XML document triggers re-labeling of pre-existing nodes. 2) They need larger memory space to store total label. etc. In this paper, we introduce a new labeling scheme called a Circle Labeling Scheme. In CLS, XML documents are represented in a circular form, and efficient storage of labels is supported by the use of concepts Rotation Number and Parent Circle/Child Circle. The concept of Radius is applied to support inclusion of new nodes at arbitrary positions in the tree. This eliminates the need for re-labeling existing nodes and the need to increase label length, and mitigates conflict with existing labels. A detailed experimental study demonstrates efficiency of CLS.

A Study for the Stability Investigation of Three Parallel Tunnels Using Scaled Model Tests (삼병렬 터널의 안정성 검토를 위한 모형실험 연구)

  • Kim, Jong-Woo;Bae, Woo-Seok
    • Tunnel and Underground Space
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    • v.18 no.4
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    • pp.300-311
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    • 2008
  • In this study, scaled model tests were performed to investigate the stability of three parallel tunnels. Seven types of test models which had respectively different pillar widths, tunnel sectional shapes, support conditions and ground conditions were experimented, where crack initiating pressures and deformation behaviors around tunnels were investigated. In order to evaluate the effect of pillar widths on stability, various models were experimented. As results, the models with shallower pillar widths proved to be unstable because of lower crack initiating pressures and more tunnel convergences than the models with thicker pillar widths. In order to find the effect of tunnel sectional shape on stability, the models with arched, semi-arched and rectangular tunnels were experimented. Among them rectangular tunnel model was the most unstable, where the arched tunnel model with small radius of roof curvature was more stable than semi-arched one. The model with rockbolt showed higher crack initiating pressure and less roof lowering than the unsupported model. The deformation behaviors of tunnels in the anisotropic ground model were quite different from those in the isotropic ground model. Futhermore, the results of FLAC analysis were qualitatively coincident with the experimental results.

Structural and Electrical Properties of (La,Nd,Sr)MnO3 Ceramics for NTC Thermistor Devices

  • Shin, Kyeong-Ha;Park, Byeong-Jun;Lim, Jeong-Eun;Lee, Sam-Haeng;Lee, Myung-Gyu;Park, Joo-Seok;Lee, Sung-Gap
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.35 no.3
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    • pp.292-296
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    • 2022
  • (La0.5Nd0.2Sr0.3)MnO3 specimens were prepared by a solid-state reaction. In all specimens, X-ray diffraction patterns of an orthorhombic structure were shown. The fracture surfaces of (La0.5Nd0.2Sr0.3)MnO3 specimens showed a transgranular fracture pattern be possibly due to La ions (0.122 nm) as a perovskite A-site dopant substituting for Nd ions (0.115 nm) having a small ionic radius. The full-width at half maximum (FWHM) of the Mn 2p XPS spectra showed a value greater than that [8] of the single valence state, which is believed to be due to the overlapping of Mn2+, Mn3+, and Mn4+ ions. The dependence of Mn 2p spectra on the Mn3+/Mn4+ ratio according to sintering time was not observed. Electrical resistivity resulted in the minimum value of 100.7 Ω-cm for the specimen sintered for 9 hours. All specimens show a typical negative temperature coefficient of resistance (NTCR) characteristics. In the 9-hour sintered specimen, TCR, activation energy, and B25/65-value were -1.24%/℃, 0.19 eV, and 2,445 K, respectively.

A SIMULATION MODEL FOR DECIDING AN OPTIMIZED 3D SHAPE OF CONSTRUCTION WORKSPACE CONSIDERING RESOURCES IN BIM ENVIRONMENT

  • Hyoun Seok Moon;Hyeon Seung Kim;Leen Seok Kang;Byung Soo Kim
    • International conference on construction engineering and project management
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    • 2013.01a
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    • pp.163-168
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    • 2013
  • A construction workspace is considered as a critical factor to secure constructability and safety of a project. Specially, optimized size of each workspace helps to minimize any conflicts between workspaces, works and resources within a workspace in the construction site. However, since an existing method for making a decision workspace's size depends on generally experiences of managers and work conditions of activity, it is difficult to perform safe works considering feasible workspace size. The workspace size is changed according to the quantity of resources allocated into each activity as time progresses. Accordingly, it is desirable that optimized workspace size considering input size of resources is determined. To solve these issues, this study configures an optimized model for deciding standard size of workspaces by simple regression analysis and develops a visualized scenario model for simulating the optimized workspace shape in order to support BIM (Building Information Modeling) environment. For this, this study determines an optimized resource shape size considering maximum working radius of each resource and constructs its visual model. Subsequently, input size of resources for each activity is estimated considering safety execution area of resources and workspaces. Based on this, an optimized 3D workspace shape is generated as a VR simulation model of a BIM system based on the suggested methodologies. Moreover, operational feasibility of the developed system is evaluated through a case study for a bride project. Therefore, this study provides a visualized framework so that project managers can establish an efficient workspace planning in BIM environment. Besides, it is expected that constructability, productivity and safety of the project will be improved by minimizing conflicts between workspace and congestions between resources within a workspace in the construction phase.

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Stability Analysis and Design of the Pretension Soil Nailing System (프리텐션 쏘일네일링 시스템의 안정해석 및 설계)

  • Park Si-Sam;Kim Hong-Taek;Choi Young-Geun
    • Journal of the Korean Geotechnical Society
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    • v.20 no.7
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    • pp.197-206
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    • 2004
  • The ground anchor support system may not be occasionally used because of space limitations in urban excavation sites nearby the existing structures. In this case, soil nailing system with relatively short length of nails could be efficiently adopted as an alternative method. The general soil nailing support system, however, may result in excessive deformations particularly in an excavation zone of the existing weak subsoils. Pretensioning the soil nails then could play important roles to reduce deformations mainly in the upper part of the nailed-soil excavation system as well as to improve local stability. In this study, a newly modified soil nailing technology named as the PSN (Pretension Soil Nailing), is developed to reduce both facing displacements and ground surface settlements in top-down excavation process as well as to increase the global stability. Up to now, the analytical procedure and design technique are proposed to evaluate maximum pretension force and stability of the PSN system. Also, proposed are techniques to determine the required thickness of a shotcrete facing and to estimate probability of a failure against the punching shear, Based on the proposed procedure and technique, effects of the radius of a influence circle and dilatancy angle on the thickness of a shotcrete facing, bonded length and safety factors are analyzed. In addition, effects of the reduction of deformations expected by pretension of the soil nails are examined in detail throughout an illustrative example and the $FLAC^{2D}$ program analysis. And a numerical approach is proposed PSN system using the shear strength reduction technique with the $FLAC^{2D}$ program.

Stability Analysis and Reliability Evaluation of the Pretensioned Soil Nailing System (프리텐션 쏘일네일링 시스템의 안정해석 및 신뢰도 분석)

  • 김홍택;강인규;박사원;고용일;권영호
    • Journal of the Korean Geotechnical Society
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    • v.15 no.2
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    • pp.105-127
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    • 1999
  • Application of the soil nailing method is continuously extended in maintaining stable excavations and slopes. Occasionally, however, ground anchor support system may not be used because of space limitations in urban excavation sites nearby the existing structures. In this case, soil nailing system with relatively short length of nails could be efficiently adopted as an alternative method. The general soil nailing support system, however, may result in excessive deformations particularly in an excavation zone of the existing weak subsoils. Pretensioning the soil nails then, could play important roles in reducing deformations mainly in an upper part of the nailed-soil excavation system as well as improving local stability. In the present study, the analytical procedure and design technique are proposed to evaluate maximum pretension force and stability of the pretensioned soil nailing system. Also proposed are techniques to determine the required thickness of a shotcrete facing and to estimate probability of a failure against the punching shear. The predicted results are compared with the limited measurements obtained from the excavation site constructed by using the pretensioned soil nails. Based on the proposed procedure and technique, effects of the radius of a influence circle and dilatancy angle on the thickness of a shotcrete facing, bonded length and safety factors are analyzed. In addition, effects of the reduction of deformations expected by pretensioning of the soil nails are examined in detail throughout an illustrative example and FLAC$^{2D}$ program analysis.s.

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