Processing math: 100%
  • Title/Summary/Keyword: surface roughness model

Search Result 493, Processing Time 0.031 seconds

Prediction of Surface Roughness and Electric Current Consumption in Turning Operation using Neural Network with Back Propagation and Particle Swarm Optimization (BP와 PSO형 신경회로망을 이용한 선삭작업에서의 표면조도와 전류소모의 예측)

  • Punuhsingon, Charles S.C;Oh, Soo-Cheol
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.14 no.3
    • /
    • pp.65-73
    • /
    • 2015
  • This paper presents a method of predicting the machining parameters on the turning process of low carbon steel using a neural network with back propagation (BP) and particle swarm optimization (PSO). Cutting speed, feed rate, and depth of cut are used as input variables, while surface roughness and electric current consumption are used as output variables. The data from experiments are used to train the neural network that uses BP and PSO to update the weights in the neural network. After training, the neural network model is run using test data, and the results using BP and PSO are compared with each other.

THE EFFECT OF SURFACE ROUGHNESS OF CSI(TL) MICRO-COLUMNS ON THE RESOLUTION OF THE X-RAY IMAGE; OPTICAL SIMULATION STUDY

  • Kim, Hyun-Ki;Bae, Jun-Hyung;Cha, Bo-Kyung;Jeon, Ho-Sang;Kim, Jong-Yul;Kim, Chan-Kyu;Cho, Gyu-Seong
    • Journal of Radiation Protection and Research
    • /
    • v.34 no.1
    • /
    • pp.25-30
    • /
    • 2009
  • Micro-columnar CsI(Tl) is the most popular scintillator material which is used for many indirect digital X-ray imaging detectors. The light scattering at the surface of micro-columnar CsI(Tl) scintillator was studied to find the correlation between the surface roughness and the resultant image resolution of indirect X-ray imaging detectors. Using a commercially available optical simulation program, Light Tools, MTF (Modulation Transfer Function) curves of the CsI(Tl) film thermally evaporated on glass substrate with different thickness were calculated and compared with the experimental estimation of MTF values by the edge X-ray image method and CCD camera. It was found that the standard deviation value of Gaussian scattering model which is determined by the surface roughness of micro-columns could certainly change the MTF value of image sensors. This model and calculation methodology will be beneficial to estimate the overall performance of indirect X-ray imaging system with CsI(Tl) scintillator film for optimum design depending on its application.

An analytical model for inversion layer electron mobility in MOSFET (MOS소자 반전층의 전자이동도에 대한 해석적 모델)

  • 신형순
    • Electrical & Electronic Materials
    • /
    • v.9 no.2
    • /
    • pp.174-179
    • /
    • 1996
  • We present a new physically based analytical equation for electron effective mobility in MOS inversion layers. The new semi-empirical model is accounting expicitly for surface roughness scattering and screened Coulomb scattering in addition to phonon scattering. This model shows excellent agreement with experimentally measured effective mobility data from three different published sources for a wide range of effective transverse field, channel doping and temperature. By accounting for screened Coulomb scattering due to doping impurities in the channel, our model describes very well the roll-off of effective mobility in the low field (threshold) region for a wide range of channel doping level (Na=3.0*1014 - 2.8*1018 cm3 ).

  • PDF

Air Quality Modeling of Ozone Concentration According to the Roughness Length on the Complex Terrain (복잡지형에서의 지표면 거칠기에 따른 오존 농도 수치모의)

  • Choi, Hyun-Jung;Lee, Hwa-Woon;Sung, Kyoung-Hee
    • Journal of Korean Society for Atmospheric Environment
    • /
    • v.23 no.4
    • /
    • pp.430-439
    • /
    • 2007
  • The objective of this work is the air quality modeling according to the practical roughness length using the building information as surface boundary conditions. As accurate wind and temperature field are required to produce realistic urban air quality modeling, comparative simulations by various roughness length are discussed. The prognostic meteorological fields and air quality field over complex areas of Seoul, Korea are generated by the PSU/NCAR mesoscale model (MM5) and the Third Generation Community Multi-scale Air Quality Modeling System (Models-3/CMAQ), respectively. The simulated O3 concentration on complex terrain and their interactions with the weak synoptic flow had relatively strong effects by the roughness length. A comparison of the three meteorological fields of respective roughness length reveals substantial localized differences in surface temperature and wind folds. Under these conditions, the ascended mixing height and weakened wind speed at night which induced the stable boundary stronger, and the difference of simulated O3 concentration is 26ppb.

Dynamic Response Analysis of Bridge-AGT Vehicle Interaction System (교량-AGT 차량 상호작용에 의한 교량의 동적응답)

  • Kim, Hyun-Ho;Rha, Sang-Ju;Song, Jae-Pil
    • Journal of the Korean Society for Railway
    • /
    • v.9 no.5 s.36
    • /
    • pp.561-568
    • /
    • 2006
  • Dynamic equations of motion for the interaction system of bridge and vehicle are derived to investigate the dynamic responses of bridge and vehicles induced by moving automated guide-way transit(AGT) vehicle and surface roughness of bridge. The vehicle model for ACT vehicle is idealized as 11 DOF including yawing, lateral translation and steering of wheels, and the bridges are modeled with finite element method. The AGT vehicle model was verified by experimental study. Parametric studies are carried out to investigate the effect of vehicle speed, surface roughness, stiffness and damping of the suspension system, AGT vehicles and dynamic wheel loads of the AGT vehicles. From the parametric study it can be seen that the dynamic incremental factor of the bridge and dynamic responses of vehicles have a tendency to increase with vehicle speeds, surface roughness and the stiffness of AGT vehicle suspension system. On the other hand those dynamic wheel loads have tendencies to decrease in according to increase of damping of the suspension system.

Modeling of Plasma Etch Process using a Radial Basis Function Network (레이디얼 베이시스 함수망을 이용한 플라즈마 식각공정 모델링)

  • Park, Kyoungyoung;Kim, Byungwhan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
    • /
    • v.18 no.1
    • /
    • pp.1-5
    • /
    • 2005
  • A new model of plasma etch process was constructed by using a radial basis function network (RBFN). This technique was applied to an etching of silicon carbide films in a NF3 inductively coupled plasma. Experimental data to train RBFN were systematically collected by means of a 24 full factorial experiment. Appropriateness of prediction models was tested with test data consisted of 16 experiments not pertaining to the training data. Prediction performance was optimized with variations in three training factors, the number of pattern units, width of radial basis function, and initial weight distribution between the pattern and output layers. The etch responses to model were an etch rate and a surface roughness measured by atomic force microscopy. Optimized models had the root mean-squared errors of 26.1 nm/min and 0.103 nm for the etch rate and surface roughness, respectively. Compared to statistical regression models, RBFN models demonstrated an improvement of more than 20 % and 50 % for the etch rate and surface roughness, respectively. It is therefore expected that RBFN can be effectively used to construct prediction models of plasma processes.

Generation of Turned Surface by Chattering (선반에서의 채터에 의한 가공 표면 시뮬레이션)

  • 홍민성;김종민
    • Transactions of the Korean Society of Machine Tool Engineers
    • /
    • v.12 no.3
    • /
    • pp.25-30
    • /
    • 2003
  • In metal cutting chatter is the unstable cutting phenomenon which caused by the interaction between the dynamics of the chip removal process and the structural dynamics of machine tool. When the vibration and chatter on, it reduces tool life and results in poor surface roughness and low productivity of the machining process. In order to observe the effect of chatter on the turned surface, the surface simulation model based on the surface-shaping system are developed under the ideal condition and the occurrence of the regenerative chatter, and it is compared with experiment of profile. In this study, the experiments were conducted in a CNC lathe without cutting fluid to investigate the phenomenon of the chatter.

Development of Roughness Estimation Model for Plunge Grinding of Valve Parts Using Neural Network (뉴럴 네트워크를 이용한 밸브 부품 생산용 플런지 연삭의 거칠기 예측모델 개발)

  • Choi, Jeong-Ju;Park, Joon-Hong
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.12 no.1
    • /
    • pp.62-67
    • /
    • 2011
  • Grinding process is executed in the final machining stage to meet the quality requirements. In generally the ground surface of workpiece is affected by dressing condition as well as grinding condition. In order to estimate the roughness of workpiece, the several roughness models have been researched. These models defined the specific parameters and considered the several parameters which affect to roughness as multiply relationship among them. However, the multiply relationship among parameters is not enough to show the complicated grinding mechanism. Therefore, the neural network algorithm is used in this paper to predict the ground roughness for the plunge grinding. The proposed structure is composed of the initial roughness as well as final roughness model. The input parameters of proposed neural network are referred with the existing roughness model's. The performance of the proposed model is verified through experiments.

Biofiltration Modeling for Packing Media Compared To a Small-scale Operation (바이오필터 담체 모델링 및 운전자료 비교에 대한 연구)

  • Huh Nam-Soo;Cho Daechul;Kwon Sung-Hyun
    • Proceedings of the KAIS Fall Conference
    • /
    • 2004.11a
    • /
    • pp.272-273
    • /
    • 2004
  • Filter media are one of themost important choices when bilfiltration is applied. Filter media provide adsorbing microbes with available sites for residence and the residential cells grow to degrade or decompose target waste gases. Up to date, filter media were only qualitatively analyzed. As a quantitative approach to filter material for biofiltration, a simple model based on reaction kinetics and mass action law (Ottengraf's Model in 1983) was presented. Cork, zeolite, and granulated activated carbon were tested in terms of effective surface area, cell covered fraction of adsorbing sites, surface roughness, and pore size distribution. The cell covered fraction, surface roughness and hydrophilicity was found to be closely related to the efficiency of gas degradation in biofiltration. The cork was the best candidate for cell residence and growth in this work.

  • PDF

Friction Model for Sheet Metal Forming Analysis(Part 2 :Mathematical Model) (박판성형 해석용 마찰 모델(2부:수학적 모델))

  • 금영탁;이봉현
    • Transactions of Materials Processing
    • /
    • v.13 no.5
    • /
    • pp.461-465
    • /
    • 2004
  • Based on the experimental observation, the mathematical friction model, which is an essential information for analyzing the forming process of sheet metal, is developed considering lubricant viscosity, surface roughness and hardness, punch comer radius, and punch speed. By comparing the punch load found by FEM with a proposed friction model with experimental measurement when the coated and uncoated steel sheets are formed in 2-D geometry in dry and lubricant conditions, the validity and accuracy of the developed friction model are demonstrated.