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3d simulation technology as an effective instructional tool for enhancing spatial visualization skills in apparel design

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INTERNATIONAL JOURNAL OF TECHNOLOGY ANd dESIGN EdUCATION 2011年第4期21卷 505-517页

作者： Park, Juyeon Kim, dong-Eun Sohn, MyungHee Colorado State Univ Dept Design & Merchandising Ft Collins CO 80523 USA Calif State Univ Long Beach Dept Family & Consumer Sci Long Beach CA 90840 USA Univ Minnesota Dept Design Housing & Apparel St Paul MN 55108 USA

The purpose of this study is to explore the effectiveness of 3d simulation technology for enhancing spatial visualization skills in apparel design education and further to suggest an innovative teaching approach using the technology. Apparel design majors in an introductory patternmaking course, at a large Midwestern University in the United States, participated in this study. Three different teaching methods (lecture, 3d simulation instruments, and paper patternmaking) were employed in consecutive instructional phases, within a single day. A short questionnaire devised to assess students' visualization abilities and overall evaluation on the three different teaching methods was administered to the students after each of the three phases. Overall, students' abilities to visualize 2d patterns onto a human body were improved by all three teaching methods. The 3d simulation instruments anchored positive effects of training on spatial visualization abilities between lecture and paper patternmaking practices. The results affirm that 3d simulation technology has positive potential as an efficient instructional tool for improving students' visualization skills in apparel design.

关键词： 3d simulation Spatial visualization Patternmaking Apparel design education

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3d simulation study on the influence of lubricant oil droplets on pre-ignition in turbocharged dISI engines

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PROCEEdINGS OF THE INSTITUTION OF MECHANICAL ENGINEERS PART d-JOURNAL OF AUTOMOBILE ENGINEERING 2018年第12期232卷 1677-1693页

作者： Huang, Yongcheng Li, Yaoting Zhang, Wenjia Meng, Fansheng Guo, Zhechen Xi An Jiao Tong Univ Sch Energy & Power Engn Xian 710049 Shaanxi Peoples R China

A skeletal chemical kinetic model for the simulation of auto-ignition and flame propagation characteristics of primary reference fuel (PRF) was developed. Coupled with this model, 3d simulations were applied to investigate the influence of lubricant oil droplets on pre-ignition in a turbocharged direct-injection spark-ignition (dISI) engine at low-speed high-load operating conditions. First, a simulation study on the influence of a lubricant oil droplet on auto-ignition of gasoline substitute and air mixture was performed in a constant-volume chamber. The results revealed that with an increase of the lubricant oil droplet diameter, the ignition delay time for the air/fuel mixture initially decreased and then increased. The ignition delay time was further shortened with the increase of the temperature of the lubricant oil droplet and the temperature and pressure of the mixture. Moreover, it was found that when n-heptane (n-C7H16) was used as a substitute for the direct evaporation product of the lubricant oil droplet, the shortening of the ignition delay time for the air/fuel mixture caused by lubricant oil evaporation was not enough to initiate pre-ignition. When octyl hydrogen peroxide ketone (C8KET) was chosen as a representative of the accumulated stable reactive radicals, the ignition delay time was significantly shortened and was short enough to trigger pre-ignition. Therefore, pre-ignition may not be induced by the direct evaporation product of an lubricant oil droplet but by the accumulated stable reactive radicals. A simulation study on auto-ignition and flame propagation of the air/fuel mixture with the presence of a lubricant oil droplet was then conducted in a turbocharged dISI engine. The results successfully predicted the auto-ignition of the air/fuel mixture near the lubricant oil droplet before the spark ignition timing. Finally, a more convincing mechanism for pre-ignition induced by lubricant oil droplets is proposed to provide some clues for furthe

关键词： Skeletal chemical kinetic model 3d simulation pre-ignition turbocharged dISI engine lubricant oil droplet ignition delay time air fuel mixture

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3d simulation Investigating ZnO NWFET Characteristics

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JOURNAL OF NANO RESEARCH 2019年 58卷 40-48页

作者： ditshego, N. M. J. Sultan, S. M. BIUST CET Elect Comp & Telecommun Engn Dept Private Bag 16 Palapye Botswana Univ Teknol Malaysia Fac Elect Engn FKE Utm Skudai 81310 Johor Darul Tak Malaysia

3d simulation was carried out and compared with fabricated ZnO NWFET. The device had the following electrical output characteristics: mobility value of 10.0 cm(2)/Vs at a drain voltage of 1.0 V, threshold voltage of 24 V, and subthreshold slope (SS) of 1500 mV/decade. The simulation showed that the device output results are influenced by two main issues: (i) contact resistance (R-con approximate to 11.3 M Omega) and (ii) interface state trapped charge number density (Q(IT) = 3.79 x 10(15) cm(-2)). The QIT was derived from the Gaussian distribution that depends on two parameters added together. These parameters are: an acceptor-like exponential band tail function g(GA)(E) and an acceptor-like Gaussian deep state function g(TA)(E). By de-embedding the contact resistance, the simulation is able to improve the device by producing excellent field effect mobility of 126.9 cm(2)/Vs.

关键词： 3d simulation field effect transistor nanowire contact resistance zinc oxide (ZnO) device de-embedding

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3d simulation of charge motion in tumbling mills by the discrete element method

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POWdER TECHNOLOGY 2001年第2期115卷 157-166页

作者： Venugopal, R Rajamani, RK Univ Utah Dept Met Engn Salt Lake City UT 84112 USA

The dynamics of charge motion in tumbling mills has been a challenging problem both experimentally and theoretically. The harsh environment within the mill precluded sophisticated sensors. On the other hand, first principle modeling of charge motion was only marginally successful since the motion involves hundreds of bodies colliding with each other. The numerical scheme known as discrete element method (dEM) is the fitting solution to this modeling problem. The three-dimensional (3d) discrete element modeling of tumbling mills is described first. The simulation results are verified against both still images of ball charge motion and power draft in experimental mills. The excellent agreement implies that the simple spring-dashpot collision model is adequate for this problem. The simulation scheme can be extended for studying the life cycle of the mill itself. (C) 2001 Elsevier Science B.V. All rights reserved.

关键词： discrete element method tumbling mills 3d simulation

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3d simulation of hydrogen ignition in a rapid compression machine

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JOURNAL OF LOSS PREVENTION IN THE PROCESS INdUSTRIES 2013年第6期26卷 1558-1568页

作者： Frolov, S. M. Emans, M. Ivanov, V. S. Basara, B. Leshevich, V. V. Penyazkov, O. G. Russian Acad Sci NN Semenov Chem Phys Inst Moscow 119991 Russia RICAM Linz Austria IMCC Linz Austria AVL LIST GmbH Graz Austria Luikov Inst Heat & Mass Transfer Minsk BELARUS

Low-temperature (at T < 900-950 K) ignition delays of hydrogen-air mixtures are mainly measured in rapid compression machines (RCM). This communication is aimed at numerical simulation of ignition delays of hydrogen-air mixtures in the RCM by means of a coupled three-dimensional (3d) Unsteady Reynolds-Averaged Navier-Stokes (URANS) - Particle Method (PM) simulation of RCM operation capable of catching turbulence-chemistry interaction. The study indicates that the time history of piston motion in an RCM affects the final state of a test mixture at the end of compression stroke and therefore influences the phenomena relevant to test mixture ignition. More specifically, the calculations show that different laws of piston motion at a fixed average piston velocity (i.e., fixed piston displacement and fixed compression time) and fixed compression ratio result in different evolution of mean pressure, temperature and velocity fields in the RCM test section leading to different ignition behavior. The reasons for the arising differences lie in the fact that the local instantaneous piston velocity determines the roll-up vortex structure, strength and turbulence dissipation in it, heat transfer in test-section walls, and mass leakage through piston rings. (C) 2013 Elsevier Ltd. All rights reserved.

关键词： Rapid compression machine Hydrogen-air mixture Ignition delay 3d simulation Turbulence-chemistry interaction

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3d simulation of the plasma jet in thermal plasma spraying

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JOURNAL OF MATERIALS PROCESSING TECHNOLOGY 2005年第2期166卷 224-229页

作者： Fan, QB Wang, L Wang, FC Beijing Inst Technol Sch Mat Sci & Engn Beijing 100081 Peoples R China

In this paper, a continuous medium model and the k-epsilon turbulence formulations are employed to predict the plasma velocity, plasma temperature and argon molar concentration fields in three-dimensional (3d) space. Some important 3d information, such as the 3d continuous isothermal lines, isovelocity lines and the 3d appearance of the plasma jet, are described. This is hard to obtain directly using a 2d scheme. The calculated results will be theoretically helpful for further analysis of the temperature history and trajectories of the entrained particles, particle molten status in the plasma jet, and the deposition of the coatings. (c) 2004 Elsevier B.V. All rights reserved.

关键词： 3d simulation plasma jet thermal plasma spraying

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3d simulation study of gate coupling and gate cross-interference in advanced floating gate non-volatile memories

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SOLId-STATE ELECTRONICS 2005年第11期49卷 1805-1812页

作者： Ghetti, A Bortesi, L Vendrame, L ST Microelectronics FTM Adv R&D NVM Technol Dev I-20041 Milan Italy

In this paper we present a 3d simulation study of gate coupling and gate cross-interference in advanced floating gate non-volatile memories. First, the simulation methodology is introduced and validated against experimental data. Then, physical effects that significantly impact the Coupling calculation are pointed Out. Finally, the method is applied to a sensitivity study of both gate coupling and gate cross-interference in different non-volatile memory architectures showing the increasing importance of this kind of analysis in designing more advanced technologies. (c) 2005 Elsevier Ltd. All rights reserved.

关键词： 3d simulation gate coupling gate interference floating gate non-volatile memories

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3d simulation of bubbling fluidized bed reactors for sorption enhanced steam methane reforming processes

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JOURNAL OF NATURAL GAS SCIENCE ANd ENGINEERING 2010年第2-3期2卷 105-113页

作者： Wang, Yuefa Chao, Zhongxi Jakobsen, Hugo A. Norwegian Univ Sci & Technol Dept Chem Engn NTNU NO-7491 Trondheim Norway

Hydrogen production by the Sorption Enhanced Steam Methane Reforming (SE-SMR) process was studied with a numerical two-fluid model. The process was simulated in a three dimensional bubbling fluidized bed reactor. The effects of pressure, steam-to-carbon ratio and inlet gas flow rate on the reactions are studied. High pressure and low steam-to-carbon ratio will decrease the conversion of methane. But the high pressure makes the adsorption of CO2 faster. Compared to the standard SMR process, the methane conversion and heat utility are enhanced by CO2 adsorption. The CO2 produced in the methane reforming process is adsorbed almost totally in a relative long period of time in the bubbling fluidized bed. It means that the adsorption rate of CO2 is fast enough compared with the SMR rate. In a certain range of gas flow rates, the mass transfer and reaction kinetics can reach the equilibrium, and the reaction efficiency is independent of gas flow rate. The temperature distribution is almost uniform over the whole reactor. (C) 2010 Elsevier Ltd. All rights reserved.

关键词： Methane reforming Carbon dioxide capture SE-SMR CaO sorbent 3d simulation Fluidized bed

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3d simulation and parametric analysis of polymer melt flowing through spiral mandrel die for pipe extrusion

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AdVANCES IN POLYMER TECHNOLOGY 2018年第8期37卷 3882-3895页

作者： Nie, Yi Hao, Jing Lin, Yueh-Jaw Sun, Wei Univ Nottingham Ningbo China Dept Mech Mat & Mfg Engn Ningbo Zhejiang Peoples R China Univ Nottingham Dept Mech Mat & Mfg Engn Nottingham England

With the increasing demands for large scale and high productivity, polymer pipes are recently produced using the advanced spiral mandrel dies. However, the fundamental research related to polymer melt flow mechanism in the spiral mandrel die for pipe extrusion is lagging behind. In the present study, the mathematical model for such a complex three-dimensional non-isothermal viscous flow of polymer melts obeying power law model was developed based on computational fluid dynamics theory. Finite volume element method was applied to predict the rheological behaviors of polymer melt flowing through the complex flow channel. The essential flow characteristics including velocity, pressure drop, wall shear stress, and temperature were investigated. The effects of both mandrel structure parameters and mass flow rate upon the flow patterns were further discussed. Some recommendations on spiral mandrel die design for pipe production were put forward.

关键词： 3d simulation extrusion polymer melt spiral mandrel die

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3d simulation estimation and experimental validation of droplet generation in CFd-based flow-focusing microfluidic chips

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JOURNAL OF MICROMECHANICS ANd MICROENGINEERING 2024年第11期34卷 115006-115006页

作者： Shu, Jingwei Chen, Wei Zhao, Yongfang Li, Minghai Ma, Zhenye Nanjing Normal Univ Sch Chem & Mat Sci Nanjing 210097 Peoples R China

Microdroplets generated using microfluidic techniques offer significant advantages over those generated using conventional methods, including high accuracy and excellent monodispersity. However, there remains a paucity of literature regarding the influence of fluid operating conditions and physical properties on droplet generation, specifically in relation to size and frequency, using computational fluid dynamics (CFd) techniques. In this study, we present a simplified microfluidic chip capable of flexibly adjusting the structure and size of the microchannels based on specific requirements. Subsequently, three-dimensional numerical simulations of this chip were conducted using CFd techniques and fitted a dimensionless model to estimate the droplet generation size and frequency through multivariate nonlinear regression methods. The experimental validation results demonstrated a strong correlation between the fitted data and the experimental observations, with size differences not exceeding 8% and good monodispersity, indicated by a coefficient of variation of less than 2.4%. This study provides valuable insights and a reference for future research.

关键词： droplet microfluidic chip flow-focusing CFd 3d simulation volume of fluid (VOF) multivariate nonlinear regression fitting

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