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Simulation

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Articles 931 - 960 of 1169

Full-Text Articles in Engineering

Simulation Of Traffic Loading On Highway Bridges, Bernard Enright Mar 2010

Simulation Of Traffic Loading On Highway Bridges, Bernard Enright

Other resources

This work is based on weigh-in-motion measurements for approximately three million trucks obtained from sites in five European countries. Techniques have been developed, supported by photographic evidence, for filtering the measurements to identify and remove unreliable values, and for the classification of extremely heavy vehicles. The collected measurements have been used as the basis for building and calibrating a Monte Carlo simulation model for bridge loading. Two-lane traffic is simulated – either two lanes in the same direction or one lane in each direction. The model allows for vehicles that are both heavier and have more axles than in the …

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Design And Validation Of A General Purpose Robotic Testing System For Musculoskeletal Applications, Lawrence D. Noble, Robb W. Colbrunn, Dong-Gil Lee, Antonie J. Van Den Bogert, Brian L. Davis Feb 2010

Design And Validation Of A General Purpose Robotic Testing System For Musculoskeletal Applications, Lawrence D. Noble, Robb W. Colbrunn, Dong-Gil Lee, Antonie J. Van Den Bogert, Brian L. Davis

Mechanical Engineering Faculty Publications

Orthopaedic research on in vitro forces applied to bones, tendons, and ligaments during joint loading has been difficult to perform because of limitations with existing robotic simulators in applying full-physiological loading to the joint under investigation in real time. The objectives of the current work are as follows: (1) describe the design of a musculoskeletal simulator developed to support in vitro testing of cadaveric joint systems, (2) provide component and system-level validation results, and (3) demonstrate the simulator’s usefulness for specific applications of the foot-ankle complex and knee. The musculoskeletal simulator allows researchers to simulate a variety of loading conditions …

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Control Law Design And Validation For A Helicopter In-Flight Simulator, Brian T. Fujizawa Feb 2010

Control Law Design And Validation For A Helicopter In-Flight Simulator, Brian T. Fujizawa

Master's Theses

In-flight simulation allows one aircraft to simulate the dynamic response of another aircraft. A control system designed to give RASCAL, a JUH-60A Black Hawk helicopter based at Moffett Field, CA, in-flight simulation capabilities has been designed, optimized and validated in this research. A classical explicit model following control system with a frequency dependent feedback controller was used. The frequency dependent controller allows model following of the attitude in the short term and the velocity in the long term. Controller gains were optimized using a high order, linearized model of UH-60 dynamics. Non-linear simulations of the control laws were performed, first …

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Modeling And Simulation Of Low Temperature Activation Processes, James D. Driscoll Jan 2010

Modeling And Simulation Of Low Temperature Activation Processes, James D. Driscoll

Journal of the Microelectronic Engineering Conference

A method for simulating dopant activation at low temperatures is proposed and tested, with a proof of concept showing the expected behavior implemented.

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Site Specific Modelling Of Traffic Loading On Highway Bridges, Bernard Enright, Eugene J. Obrien Jan 2010

Site Specific Modelling Of Traffic Loading On Highway Bridges, Bernard Enright, Eugene J. Obrien

Conference papers

Accurate traffic loading models based on measured weigh-in-motion (WIM) data are essential for the accurate assessment of existing bridges. Much work has been published on the Monte Carlo simulation of single lanes of heavy vehicle traffic, and this can easily be extended to model the loading on bridges with two streams of traffic in opposing directions. However, a typical highway bridge will have multiple lanes in the same direction, and various types of correlation are evident in measured traffic, such as groups of very heavy vehicles travelling together and heavy vehicles being overtaken by lighter ones. These traffic patterns affect …

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Practical Simulation Application: Evaluation Of Process Control Parameters In Twisted-Pair Cables Manufacturing System, Amr Mahfouz, Amr Arisha Jan 2010

Practical Simulation Application: Evaluation Of Process Control Parameters In Twisted-Pair Cables Manufacturing System, Amr Mahfouz, Amr Arisha

Articles

Intensive competition and rapid technology development of Twisted-Pair Cables (TPC) industry have left no room for competing manufacturers to harbour system inefficiencies. TPC are used in various communication and networks hardware applications; their manufacturing facilities face many challenges including various product configurations with different equipment settings, different product flows and Work in Process (WIP) space limitations. The quest for internal efficiency and external effectiveness forces companies to align their internal settings and resources with external requirements/orders, or in different words, significant factors must be set appropriately and identified prior to manufacturing processes. Integrated definition models (IDEF0, IDEF3) in conjunction with …

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Importance Of The Tail In Truck Weight Modeling For Bridge Assessment, Eugene J. Obrien, Bernard Enright, Abraham Getachew Jan 2010

Importance Of The Tail In Truck Weight Modeling For Bridge Assessment, Eugene J. Obrien, Bernard Enright, Abraham Getachew

Articles

To predict characteristic extreme traffic load effects, simulations are sometimes performed of bridge loading events. To generalize the truck weight data, statistical distributions are fitted to histograms of weight measurements. This paper is based on extensive WIM measurements from two European sites and shows the sensitivity of the characteristic traffic load effects to the fitting process. A semi-parametric fitting procedure is proposed: direct use of the measured histogram where there are sufficient data for this to be reliable and parametric fitting to a statistical distribution in the tail region where there are less data. Calculated characteristic load effects are shown …

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The Influence Of Correlation On The Extreme Traffic Loading Of Bridges, Eugene J. Obrien, Bernard Enright, A. T. Dempsey Jan 2010

The Influence Of Correlation On The Extreme Traffic Loading Of Bridges, Eugene J. Obrien, Bernard Enright, A. T. Dempsey

Conference papers

Accurate traffic loading models based on measured data are essential for the accurate assessment of existing bridges. There are well-established methods for the Monte Carlo simulation of single lanes of traffic, and this can easily be extended to model the loading on bridges with two independent streams of traffic in opposing directions. However, a typical highway bridge will have multiple lanes in the same direction, and various types of correlation are evident in measured traffic. This paper analyses traffic patterns using multi-lane WIM data collected at two European sites. It describes an approach to the Monte Carlo simulation of this …

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The History, Philosophy, And Practice Of Agent-Based Modeling And The Development Of The Conceptual Model For Simulation Diagram, Brian L. Heath Jan 2010

The History, Philosophy, And Practice Of Agent-Based Modeling And The Development Of The Conceptual Model For Simulation Diagram, Brian L. Heath

Browse all Theses and Dissertations

This research advances ABM as a generic analysis tool such that ABM can reach its full potential as a revolution in modeling and simulation. To achieve this goal, the field of ABM is examined from many perspectives. The first perspectives examined are complex systems, the historical emergence of ABM, and philosophical issues related to ABM. These topics establish some clear foundations for the field across multiple disciplines. Next the current practice of ABM is investigated. Through a comprehensive 279 article survey some current deficiencies and opportunities in ABM are identified. Based on these opportunities, a new diagramming technique called the …

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A Methodology To Stabilize The Supply Chain, Alfonso Sarmiento Jan 2010

A Methodology To Stabilize The Supply Chain, Alfonso Sarmiento

Electronic Theses and Dissertations

In today's world, supply chains are facing market dynamics dominated by strong global competition, high labor costs, shorter product life cycles, and environmental regulations. Supply chains have evolved to keep pace with the rapid growth in these business dynamics, becoming longer and more complex. As a result, supply chains are systems with a great number of network connections among their multiple components. The interactions of the network components with respect to each other and the environment cause these systems to behave in a highly nonlinear dynamic manner. Ripple effects that have a huge, negative impact on the behavior of the …

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Behaviors Of Real-Time Schedulers Under Resource Modification And A Steady Scheme With Bounded Utilization, Refi̇k Samet, Orhan Fi̇kret Duman Jan 2010

Behaviors Of Real-Time Schedulers Under Resource Modification And A Steady Scheme With Bounded Utilization, Refi̇k Samet, Orhan Fi̇kret Duman

Turkish Journal of Electrical Engineering and Computer Sciences

In this article we present an analysis for task models having random resource needs and different arrival patterns. In hard real-time environments like avionic systems or nuclear reactors, the inputs to the system are obtained from real world by using sensors. And it is highly possible for a task to have different resource needs for each period according to these changing conditions of real world. We made an analysis of schedulers for task models having random resources in each period. Since feasibility tests for usual task models are just limited to some specific schedulers and arrival patterns, we made our …

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Simulation Model To Investigate Flexible Workload Management For Healthcare And Servicescape Environment, Michael Thorwarth, Paul Harper, Amr Arisha Dec 2009

Simulation Model To Investigate Flexible Workload Management For Healthcare And Servicescape Environment, Michael Thorwarth, Paul Harper, Amr Arisha

Conference papers

High demand and poor staffing conditions cause avoidable pressure and stress among healthcare personnel which results in burnout symptoms and unplanned absenteeism which are hidden cost drivers. The work environment within an emergency department is commonly arranged in a flexible workload which is highly dynamic and complex for the outside observer. Using detailed simulation modeling within structured modeling methods, a comprehensive model to characterize the nurses' time utilization in such flexible dynamic workload environment was investigated. The results have been used to derive a generalized analytic expression that describes certain settings that lead to an instable queuing system with serious …

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Development Of A Methodology For Numerical Simulation Of A D C Arc Discharge In A Liquid Dielectric, Christopher James Lewis Dec 2009

Development Of A Methodology For Numerical Simulation Of A D C Arc Discharge In A Liquid Dielectric, Christopher James Lewis

Theses and Dissertations

The majority of literature regarding the numerical simulation of arc discharges in gaseous environments has used a plasma physics approach. Virtually all simulations treat the discharge as an idealized gaseous plasma, which can be described by temperature, pressure, and electric field. This approach can work well if the media is a shielding gas such as Argon; however, the approach does not work well for processes such as underwater welding, EDM, and underwater discharges used to generate high purity particles. The reason these discharges do not have many extensive simulation efforts as described in the literature is because they occur in …

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Prediction Of Fluid Viscosity Through Transient Molecular Dynamic Simulations, Jason Christopher Thomas Dec 2009

Prediction Of Fluid Viscosity Through Transient Molecular Dynamic Simulations, Jason Christopher Thomas

Theses and Dissertations

A novel method of calculating viscosity from molecular dynamics simulations is developed, benchmarked, and tested. The technique is a transient method which has the potential to reduce CPU requirements for many conditions. An initial sinusoidal velocity profile is overlaid upon the peculiar velocities of the individual molecules in an equilibrated simulation. The transient relaxation of this initial velocity profile is then compared to the corresponding analytical solution of the momentum equation by adjusting the viscosity-related parameters in the constitutive equation that relate the shear rate to the stress tensor. The newly developed Transient Molecular Dynamics (TMD) method was tested for …

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Stochastic Analysis Of Electrostatic Mems Subjected To Parameter Variations, Nitin Agarwal, Narayana R. Aluru Dec 2009

Stochastic Analysis Of Electrostatic Mems Subjected To Parameter Variations, Nitin Agarwal, Narayana R. Aluru

PRISM: NNSA Center for Prediction of Reliability, Integrity and Survivability of Microsystems

This paper presents an efficient stochastic framework for quantifying the effect of stochastic variations in various design parameters such as material properties, geometrical features, and/or operating conditions on the performance of electrostatic microelectromechanical systems (MEMS) devices. The stochastic framework treats uncertainty as a separate dimension, in addition to space and time, and seeks to approximate the stochastic dependent variables using sparse grid interpolation in the multidimensional random space. This approach can be effectively used to compute important information, such as moments (mean and variance), failure probabilities, and sensitivities with respect to design variables, regarding relevant quantities of interest. The approach …

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Probabilistic Remediation Evaluation Model For Chlorinated Solvents Considering Uncertainty, Hailian Liang Dec 2009

Probabilistic Remediation Evaluation Model For Chlorinated Solvents Considering Uncertainty, Hailian Liang

All Dissertations

The complex processes and expensive costs of source and plume remediation of dense, non-aqueous phase liquid (DNAPL) complicate the decision-making process for site remediation. Selection of remediation alternatives has been a big challenge due to the lack of tools that simultaneously evaluate the effectiveness of source and plume remediation and access the uncertainties in all major parameters. In this research, a new probabilistic remediation model, Probabilistic Remediation Evaluation Model for Chlorinated solvents sites (PREMChlor), has been developed. This is achieved through linking the analytical model REMChlor to a Monte Carlo modeling simulation package GoldSim via a FORTRAN Dynamic Link Library …

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Course Portfolio - Discrete Event Simulation, Paul Savory Oct 2009

Course Portfolio - Discrete Event Simulation, Paul Savory

Department of Industrial and Management Systems Engineering: Faculty Publications

This course portfolio, written by Dr. Paul Savory, provides an overview of his Discrete Event Simulation course at the University of Nebraska-Lincoln. It offers an overview of the course goals, a summary of the classroom activities for achieving them, and a detailed assessment of student learning. He highlights his introduction of the simul8 programming environment to his students. In addition to exploring his students’ learning, Dr. Savory also explores different approaches for documenting his teaching by including multimedia clips (video and audio), uses graphs, uses color, and incorporates images. The resulting portfolio is one that can be reviewed, shared, and …

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Preliminary Modelling Results For An Otto Cycle/Stirling Cycle Hybrid-Engine-Based Power Generation System, Barry Cullen, Jim Mcgovern, Michel Feidt, Stoian Petrescu Aug 2009

Preliminary Modelling Results For An Otto Cycle/Stirling Cycle Hybrid-Engine-Based Power Generation System, Barry Cullen, Jim Mcgovern, Michel Feidt, Stoian Petrescu

Conference Papers

This paper presents preliminary data and results for a system mathematical model for a proposed Otto Cycle / Stirling Cycle hybrid-engine-based power generation system. The system is a combined cycle system with the Stirling cycle machine operating as a bottoming cycle on the Otto cycle exhaust. The application considered is that of a stationary power generation scenario wherein the Stirling cycle engine operates as a waste heat recovery device on the exhaust stream of the Otto cycle engine. This paper is primarily concerned with the development of a model for a suitable Stirling cycle engine capable of running on the …

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Geographic Variation In Potential Of Residential Solar Hot Water System Performance In The United States, Florida Solar Energy Center, Camilo Gil Aug 2009

Geographic Variation In Potential Of Residential Solar Hot Water System Performance In The United States, Florida Solar Energy Center, Camilo Gil

FSEC Energy Research Center®

This paper describes an assessment of residential solar water heater performance around the continental United States. We performed annual simulations using an hourly simulation model (EGUSA) for 212 TMY3 weather locations around the nation. The annual simulations show how standard hot water energy use for electric and gas systems vary geographically (kWh and therms) as well as the potential energy savings from solar water heaters. A key finding is that the energy necessary for water heating varies by 2:1 around the U.S. with implications for solar water heating system design and sizing. Our results provide information on expected water heater …

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Simulation Modeling Of Electronic Health Records Adoption In The U.S. Healthcare System, Nadiye O. Erdil, C. Robert Emerson Jul 2009

Simulation Modeling Of Electronic Health Records Adoption In The U.S. Healthcare System, Nadiye O. Erdil, C. Robert Emerson

Engineering and Applied Science Education Faculty Publications

Increasing the efficiency of the healthcare system in the United States is an important subject due to rapidly rising costs. Among many propositions to improve the operation of the system, adoption of Electronic Health Records is widely discussed. This study uses a system dynamics methodology to develop a simulation model of the adoption process that will allow for the exploration of policies. This paper presents the development and the preliminary findings of this model.

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Modelling Of Coal Slag Flow And Layer Thickness In A High Temperature Entrained Flow Gasifier, H. Katalambula Jun 2009

Modelling Of Coal Slag Flow And Layer Thickness In A High Temperature Entrained Flow Gasifier, H. Katalambula

Tanzania Journal of Engineering and Technology (TJET)

A 2-D model for the slag flow simulation in an entrained flow gasifier has been developed. In addition to mass, momentum and energy conservation equations, volume of fluid (VOF) equation was solved to track the liquid-gas interface. Liquid phase consists of melted coal ash particles which deposits on the wall and move downward. The gasification reaction is not considered here but it is postulated to have a mass flow through the interface towards the mass of the liquid phase. The reactor walls are usually kept cold so a temperature gradient and then a solid layer form within the slag layer. …

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Chilling Out In The Sim: The Need For Icing Training., Nihad E. Daidzic Jun 2009

Chilling Out In The Sim: The Need For Icing Training., Nihad E. Daidzic

Aviation Department Publications

No abstract provided.

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Development Of A Nonlinear Ride Quality Model To Aid In Tweelå© Parameter Selection, Marc Paradiso May 2009

Development Of A Nonlinear Ride Quality Model To Aid In Tweelå© Parameter Selection, Marc Paradiso

All Theses

The ride comfort of a vehicle is very important to both automotive and tire manufacturers. Unfortunately the ride comfort provided by the tire has an inverse relationship with the handling ability of the vehicle. Michelin has sought to decouple ride comfort and handling capability by developing a non-pneumatic tire they have dubbed the TWEEL©. To better understand what effects fitting a TWEEL with specific characteristics would have on the ride comfort of a vehicle a computer simulation was developed to study the effects of TWEEL stiffness and deflection on ride comfort.
The vehicle model used in the simulation is a …

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A Real-Time, 3-D Musculoskeletal Model For Dynamic Simulation Of Arm Movements, Edward K. Chadwick, Dimitra Blana, Antonie J. Van Den Bogert, Robert F. Kirsch Apr 2009

A Real-Time, 3-D Musculoskeletal Model For Dynamic Simulation Of Arm Movements, Edward K. Chadwick, Dimitra Blana, Antonie J. Van Den Bogert, Robert F. Kirsch

Mechanical Engineering Faculty Publications

Neuroprostheses can be used to restore movement of the upper limb in individuals with high-level spinal cord injury. Development and evaluation of command and control schemes for such devices typically require real-time, ldquopatient-in-the-looprdquo experimentation. A real-time, 3-D, musculoskeletal model of the upper limb has been developed for use in a simulation environment to allow such testing to be carried out noninvasively. The model provides real-time feedback of human arm dynamics that can be displayed to the user in a virtual reality environment. The model has a 3-DOF glenohumeral joint as well as elbow flexion/extension and pronation/supination and contains 22 muscles …

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The Effect Of Whole And Part-Task Training And Feedback During Simulated Instrument Flight Training, Christian Jon Rossi Apr 2009

The Effect Of Whole And Part-Task Training And Feedback During Simulated Instrument Flight Training, Christian Jon Rossi

Master's Theses - Daytona Beach

The most cost effective method for training novice pilot’s instrument flight procedures has not been well investigated. Part-task scenarios condition and a whole task scenarios condition, both with different levels of feedback were compared in a between group study of novice pilots learning a 737 instrument approach with Microsoft ESP flight simulator. The two different types of training methods were evaluated after a series of training exposures by comparing the ability to pass a series of training scenarios along with a final test. This standard was created by 737 pilots, FAA regulations, and 737 instructors. These training methods were also …

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The Relationships Between Muscle, External, Internal And Joint Mechanical Work During Normal Walking, Kotaro Sasaki, Richard R. Neptune, Steven A. Kautz Mar 2009

The Relationships Between Muscle, External, Internal And Joint Mechanical Work During Normal Walking, Kotaro Sasaki, Richard R. Neptune, Steven A. Kautz

Mechanical and Biomedical Engineering Faculty Publications and Presentations

Muscle mechanical work is an important biomechanical quantity in human movement analyses and has been estimated using different quantities including external, internal and joint work. The goal of this study was to investigate the relationships between these traditionally used estimates of mechanical work in human walking and to assess whether they can be used as accurate estimates of musculotendon and/or muscle fiber work. A muscle-actuated forward dynamics walking simulation was generated to quantify each of the mechanical work measures. Total joint work (i.e. the time integral of absolute joint power over a full gait cycle) was found to underestimate total …

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A Simulator For Euv Lithography Mirrors, Thiago S. Jota Jan 2009

A Simulator For Euv Lithography Mirrors, Thiago S. Jota

Journal of the Microelectronic Engineering Conference

The design of a simulator for EUV lithography mirrors is presented. A method of computing the expected value of reflectance and transmittance in stratified absorbing media with rough interfaces, based on Jay Eastman’s matrix formalism for scattered fields, was developed. In addition, a proof of principle experiment confirmed process feasibility for EUV mirror research at RIT.

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4-Bit Microprocessor: Design, Simulation, Fabrication, And Testing, A J. Ryan, G O. Phillips, R E. Pearson, L F. Fuller Jan 2009

4-Bit Microprocessor: Design, Simulation, Fabrication, And Testing, A J. Ryan, G O. Phillips, R E. Pearson, L F. Fuller

Journal of the Microelectronic Engineering Conference

The work presented demonstrates the unique ability of Rochester Institute of Technology’s Microelectronic Engineering department to design, simulate, fabricate, and test complex digital integrated circuits. Utilizing the resources available, the author would be the first undergraduate at RIT to successfully drive the creation of a microprocessor from design through fabrication to test. The microprocessor created is the most complex digital circuit ever fabricated at RIT. Fabrication was completed on three lots using the well-established RIT sub μm CMOS Process. Functional CMOS transistors were demonstrated at the Metal 1 level, but complex digital integrated circuits were not realized beyond that.

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Utilizing Strategic Project Management Processes And The Nato Code Of Best Practice To Improve Management Of Experimentation Events, Andreas Tolk, Rafael E. Landaeta, Robert H. Kewley, Thomas T. Litwin Jan 2009

Utilizing Strategic Project Management Processes And The Nato Code Of Best Practice To Improve Management Of Experimentation Events, Andreas Tolk, Rafael E. Landaeta, Robert H. Kewley, Thomas T. Litwin

Computational Modeling & Simulation Engineering Faculty Publications

Systems engineering and project management are two core engineering management processes supported by core quantitative disciplines within engineering management problems. Traditional approaches to systems engineering focus on a single system being engineered and managed (i.e., project managed), while challenges addressing composition of systems of systems and the reuse of systems for new solutions require a strategic management approach that promote a process flow in which the outputs of one project (e.g., deliverables, knowledge, work documents) are captured for the benefit of other projects within and outside the project-based organization. Two other core processes of engineering management are therefore critical to …

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Simulation Of Corn Stover And Distillers Grains Gasification With Aspen Plus, Ajay Kumar, Hossein Noureddini, Yaşar Demirel, David Jones, Milford Hanna Jan 2009

Simulation Of Corn Stover And Distillers Grains Gasification With Aspen Plus, Ajay Kumar, Hossein Noureddini, Yaşar Demirel, David Jones, Milford Hanna

Yaşar Demirel Publications

A model was developed to simulate the performance of a lab‐scale gasifier and predict the flowrate and composition of product from given biomass composition and gasifier operating conditions using Aspen Plus software. Mass balance, energy balance, and minimization of Gibbs free energy during the gasification were applied to determine the product gas composition. Carbon conversion efficiency and tar content were provided to the model as inputs as these could not be predicted by the model based on minimization of Gibbs free energy. Experiments for validation of the model were performed on a lab‐scale fluidized bed gasifier using corn stover and …

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