Open Access. Powered by Scholars. Published by Universities.®
- Discipline
-
- Mechanical Engineering (1144)
- Aerospace Engineering (814)
- Manufacturing (209)
- Materials Science and Engineering (96)
- Structures and Materials (50)
-
- Physical Sciences and Mathematics (39)
- Electrical and Computer Engineering (31)
- Ceramic Materials (24)
- Metallurgy (20)
- Computer Sciences (16)
- Engineering Mechanics (16)
- Engineering Science and Materials (16)
- Aerodynamics and Fluid Mechanics (14)
- Chemistry (14)
- Physics (13)
- Systems Engineering and Multidisciplinary Design Optimization (13)
- Chemical Engineering (7)
- Civil and Environmental Engineering (7)
- Numerical Analysis and Scientific Computing (6)
- Operations Research, Systems Engineering and Industrial Engineering (4)
- Materials Chemistry (3)
- Mathematics (3)
- Biology (2)
- Business (2)
- Education (2)
- Electromagnetics and Photonics (2)
- Life Sciences (2)
- Mining Engineering (2)
- Statistics and Probability (2)
- Keyword
-
- Additive manufacturing (44)
- Optimal Control (41)
- Neurocontrollers (26)
- Nonlinear Control Systems (23)
- Control System Synthesis (20)
-
- Adaptive Control (13)
- Stability (13)
- Feedback (11)
- Additive Manufacturing (10)
- Mechanical properties (10)
- Solid Freeform Fabrication (10)
- Laser metal deposition (9)
- Neural Nets (9)
- Neural networks (9)
- 3D printers (8)
- Deposition (8)
- Distributed Parameter Systems (8)
- Dynamic Programming (8)
- Neural Networks (8)
- Robots (8)
- Aerospace Control (7)
- Composites (7)
- Directed energy deposition (7)
- Finite element analysis (7)
- Learning Systems (7)
- Machine learning (7)
- Microstructure (7)
- Optimal control (7)
- Plasmonics (7)
- Position Control (7)
- Publication Year
Articles 1081 - 1110 of 1287
Full-Text Articles in Engineering
Development Of A Functional Basis For Design, Robert B. Stone, Kristin L. Wood
Development Of A Functional Basis For Design, Robert B. Stone, Kristin L. Wood
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Functional models represent a form independent blueprint of a product. As with any blueprint or schematic, a consistent language or coding system is required to ensure others can read it. This paper introduces such a design language, called a functional basis, where product function is characterized in a verb-object (function-flow) format. The set of functions and flows is intended to comprehensively describe the mechanical design space. Clear definitions are provided for each function and flow. The functional basis is compared to previous functional representations and is shown to subsume these attempts as well as offer a more consistent classification scheme. …
Carryover For Hypersonic '+' And 'X' Configuration Delta Fin Missiles, Harlan F. Nelson
Carryover For Hypersonic '+' And 'X' Configuration Delta Fin Missiles, Harlan F. Nelson
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The Zonal Euler Solver code (ZEUS) is used to predict hypersonic missile flow fields and to determine the carryover factors for the effect of the body on wing lift, Kw(B), and for the effect of the wing on body lift, KB(w). Results are presented for Mach 4, 6, 8, and 10 at an angle of attack of 2 deg. The missile has a conical nose and a cylindrical fuselage with a 1-degree flair angle. Both 'x' and '+' fin configurations are considered. Results are given for 20 and 30 deg semi vertex angles as a function of fur span to …
Tuning Parameter Tolerance Design: Foundations, Methods, And Measures, Daniel A. Mcadams, Kristin L. Wood
Tuning Parameter Tolerance Design: Foundations, Methods, And Measures, Daniel A. Mcadams, Kristin L. Wood
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this paper, a novel technique is presented to solve tolerance design problems. To achieve the desired performance tolerance, the technique uses a subtle, but significant, change in the design: the addition of a tuning parameter in place of an increase in component precision. Statistical models are used to develop a framework for the tuning parameter design method. Also developed is a new, dimensionless design metric which ranks candidate tuning parameters. A step-by-step method is developed for the application of tuning parameters using this metric. The step-by-step tuning parameter design method is applied to a heavy-duty manual stapler as a …
A Heuristic Method For Identifying Modules For Product Architectures, Robert B. Stone, Kristin L. Wood, Richard H. Crawford
A Heuristic Method For Identifying Modules For Product Architectures, Robert B. Stone, Kristin L. Wood, Richard H. Crawford
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Developing product architectures is a key phase in design and development processes. It encompasses the transformation of product function to alternative product layouts. In this paper, we describe a new approach for identifying modules for product architectures. We begin by reviewing the terminology and motivation for modular products. The new concepts of a functional basis and time ordered function chains are used to formally derive functional models of products. Then, three heuristic methods for identifying modules from functional models are presented. Using the formal functional decomposition and heuristic methods, modular design can be executed earlier in the product development process, …
Using Quantitative Functional Models To Develop Product Architectures, Robert B. Stone, Kristin L. Wood, Richard H. Crawford
Using Quantitative Functional Models To Develop Product Architectures, Robert B. Stone, Kristin L. Wood, Richard H. Crawford
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Developing product architectures is a key phase in design and development processes. It encompasses the transformation from functional model to alternative product layouts. In this paper, we introduce a methodology for representing a functional model of a product in a quantitative manner. In addition to describing product functionality, the quantitative functional model also incorporates customer need ratings. Product design knowledge can be archived and transmitted in databases using this novel representation. Numerical manipulations of such a database assist in developing product architectures. In particular, product families and customer need ratings for modules are easily computed. Prior to the methodology, a …
Infinite Time Optimal Neuro Control For Distributed Parameter Systems, S. N. Balakrishnan, Radhakant Padhi
Infinite Time Optimal Neuro Control For Distributed Parameter Systems, S. N. Balakrishnan, Radhakant Padhi
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The conventional dynamic programming methodology for the solution of optimal control, despite having many desirable features, is severely restricted by its computational requirements. However, in recent times, an alternate formulation, known as the adaptive-critic synthesis, has given it a new perspective. In this paper, we have attempted to use the philosophy of adaptive-critic design to the optimal control of distributed parameter systems. An important contribution of this study is the derivation of the necessary conditions of optimality for distributed parameter systems, described in discrete domain, following the principle of approximate dynamic programming. Then the derived necessary conditions of optimality are …
Galnnas Resonant-Cavity-Enhanced Photodetector Operating At 1.3 Μm, J. B. Heroux, Xiaodong Yang, W. I. Wang
Galnnas Resonant-Cavity-Enhanced Photodetector Operating At 1.3 Μm, J. B. Heroux, Xiaodong Yang, W. I. Wang
Mechanical and Aerospace Engineering Faculty Research & Creative Works
We demonstrate a GaAs-based p-i-n resonant-cavity-enhanced (RCE) GalnNAs photodetector operating near 1.3 µm. The device design was optimized using a transfer matrix method and experimental absorption spectra obtained from p-i-n structures grown without a resonant cavity. The RCE photodetector was fabricated in a single growth step by using GaAs/AlAs distributed Bragg reflectors for the top and bottom mirrors. A 72% quantum efficiency was obtained with a full width at half maximum of 11 nm.
An Experimental And Analytical Study Of Ice Part Fabrication With Rapid Freeze Prototyping, Wei Zhang, Ming-Chuan Leu, Guanghua Sui, Zhiming Ji
An Experimental And Analytical Study Of Ice Part Fabrication With Rapid Freeze Prototyping, Wei Zhang, Ming-Chuan Leu, Guanghua Sui, Zhiming Ji
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Rapid Freeze Prototyping (RFP) is a new solid freeform fabrication process that builds an ice part by rapidly freezing water layer by layer. In this paper, we will present our recent progress in the development of this novel process. An experimental system has been built for conducting the research. It consists of an XY-table and Z-stroke driven by micro-stepping motors and a water dispensing and deposition subsystem which incorporates a solenoid valve and a syringe pump placed inside a freezer. Simple heat transfer analysis is made to help select proper values of process parameters and predict part building failures. Example …
Assessment Of Environmental Performance Of Rapid Prototyping And Rapid Tooling Processes, Yanchun Luo, Ming-Chuan Leu, Zhiming Ji
Assessment Of Environmental Performance Of Rapid Prototyping And Rapid Tooling Processes, Yanchun Luo, Ming-Chuan Leu, Zhiming Ji
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A method for assessing the environmental performance of solid freeform fabrication (SFF) based rapid prototyping and rapid tooling processes is presented in this paper. In this method of assessment, each process is divided into a number of life stages. The environmental effect of each process stage is analyzed and evaluated based on an environmental index utilizing the Eco-indicators that were compiled by PreConsultants of the Netherlands. The effects of various life stages are then combined to obtain the environmental performance of a process. In the assessment of SFF processes, we consider the material use in the fabrication of a part, …
Rapid Tooling By Integrating Electroforming And Solid Freeform Fabrication Techniques, Bo Yang, Ming-Chuan Leu
Rapid Tooling By Integrating Electroforming And Solid Freeform Fabrication Techniques, Bo Yang, Ming-Chuan Leu
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper describes a rapid tooling process that integrates solid freeform fabrication (SFF) with electroforming to produce metal tools including molds, dies, and electrical discharge machining (EDM) electrodes. Based on experimental data analysis, the geometry and material of the SFF part, the properties of the electroformed metal, and the process parameters are significant factors that cause inaccuracy in the manufactured tools. Thermomechanical modeling and numerical simulation is used to determine the geometry of the SFF part and the electroform thickness for minimizing the manufacturing time and cost while satisfying the tooling accuracy requirement.
Grain Oriented Crystallization, Piezoelectric, And Pyroelectric Properties Of (Baxsr₂ - X)Tisi₂O₈ Glass Ceramics, Jianping Zhang, Burtrand I. Lee, Robert W. Schwartz, Zhenya Ding
Grain Oriented Crystallization, Piezoelectric, And Pyroelectric Properties Of (Baxsr₂ - X)Tisi₂O₈ Glass Ceramics, Jianping Zhang, Burtrand I. Lee, Robert W. Schwartz, Zhenya Ding
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Polar, nonferroelectric (BaxSr2 - x)TiSi2O8 glass ceramics with highly oriented crystallites were prepared by a gradient temperature heat treatment technique. The crystallization mechanism and microstructures of (BaxSr2 - x)TiSi2O8 glass ceramics were investigated by means of differential thermal analysis, x-ray diffraction and scanning electron microscopy, and the dielectric, piezoelectric and pyroelectric properties were investigated for various compositions. The results show that polar (BaxSr2 - x)TiSi2O8 glass ceramics have a low dielectric constant and a high hydrostatic figure of merit dh × gh = ~ 2500. This high hydrostatic figure of merit, along with other unique characteristics, such as no aging …
Frequency Domain Robustness Analysis Of Hopfield And Modified Hopfield Neural Networks, Jie Shen, S. N. Balakrishnan
Frequency Domain Robustness Analysis Of Hopfield And Modified Hopfield Neural Networks, Jie Shen, S. N. Balakrishnan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A variant of Hopfield neural network, called the modified Hopfield network, is formulated in this study. This class of networks consists of parallel recurrent networks which have variable dimensions that can be changed to fit the problem under consideration. It has a structure to implement an inverse transformation that is essential for embedding optimal control gain sequences. Equilibrium solutions of this network are discussed. The robustness of this network and the classical Hopfield network are carried out in the frequency domain using describing functions
Online Identification And Control Of Aerospace Vehicles Using Recurrent Networks, Zhenning Hu, S. N. Balakrishnan
Online Identification And Control Of Aerospace Vehicles Using Recurrent Networks, Zhenning Hu, S. N. Balakrishnan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Methods for estimating the aerospace system parameters and controlling them through two neural networks are presented in this study. We equate the energy function of Hopfield neural network to integral square of errors in the system dynamics and extract the parameters of a system. Parameter convergence is proved. For control, we equate the equilibrium status of a "modified" Hopfield neural network to the steady state Riccati solution with the system parameters as inputs. Through these two networks, we present the online identification and control of an aircraft using its nonlinear dynamics.
Stability Analysis Of Nonlinear Machining Force Controllers, Robert G. Landers, Yen-Wen Lu
Stability Analysis Of Nonlinear Machining Force Controllers, Robert G. Landers, Yen-Wen Lu
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Model parameters vary significantly during a normal operation, thus, adaptive techniques have predominately been used. However, model-based techniques that carefully account for changes in the force process have again been examined due to the reduced complexity afforded by such techniques. In this paper, the effect of model parameter variations on the closed-loop stability for two model-based force controllers is examined. It was found that the stability boundary in the process parameter space can be exactly determined for force control systems designed for static force processes. For force control systems designed for first-order force processes, it was found that the stability …
Hypersonic Drag And Heat Transfer Reduction Using A Forward Facing Jet, Benjamin Meyer, Harlan F. Nelson, David W. Riggins
Hypersonic Drag And Heat Transfer Reduction Using A Forward Facing Jet, Benjamin Meyer, Harlan F. Nelson, David W. Riggins
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A two-dimensional numerical study of the effects of a forward-facing jet located at the stagnation point of a blunt body on wave drag, heat transfer, and skin friction drag is presented for Mach 6.5 flow at 30 km altitude. The full Navier-Stokes equations are used with variable viscosity and thermal conductivity. It is shown that upstream injection can significantly modify the flow field. If the jet conditions are chosen properly, large reductions in drag and heat transfer can be obtained resulting in possible increases in the volumetric efficiency and static stability of aircraft and reductions in heating protection requirements for …
Functional Interdependence And Product Similarity Based On Customer Needs, Daniel A. Mcadams, Robert B. Stone, Kristin L. Wood
Functional Interdependence And Product Similarity Based On Customer Needs, Daniel A. Mcadams, Robert B. Stone, Kristin L. Wood
Mechanical and Aerospace Engineering Faculty Research & Creative Works
In this paper, related product functions are determined for a group of approximately 70 consumer products. Using customer need data, a new matrix approach is introduced to identify these relationships. Techniques are then created for determining product similarity. These techniques are clarified and validated through three case studies, including beverage brewers and material-removal products. The results of these case studies are argued to have significant impact on design-by-analogy procedures, benchmarking methods, mass customization strategies and modular design. The paper concludes with a discussion of applications and related procedures for product development.
A New Reflection Free Boundary In Uniform Flow Using Mapped Infinite Wave Envelope Elements, Walter Eversman, Indranil Danda Roy
A New Reflection Free Boundary In Uniform Flow Using Mapped Infinite Wave Envelope Elements, Walter Eversman, Indranil Danda Roy
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Variable order mapped infinite wave envelope elements are developed for finite element modeling of acoustic radiation in a uniformly moving medium. These elements can be used outside of the near field as a non-reflecting boundary condition for computations on an infinite domain in which a radiating body is immersed in a moving medium. Mapped infinite wave envelope elements provide a boundary condition equivalent to stiffness, mass, and damping matrices appended to the inner mesh. A demonstration of the characteristics of the mapped infinite wave envelope elements is given in the context of acoustic radiation from a turbofan inlet for which …
Design, Optimization, And The Prototyping Of A Small Tuning-Fork Ultrasonic Piezoelectric Linear Motor, Daniel S. Stutts, James R. Friend
Design, Optimization, And The Prototyping Of A Small Tuning-Fork Ultrasonic Piezoelectric Linear Motor, Daniel S. Stutts, James R. Friend
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The design, optimization, and properties of a prototype small traveling-wave ultrasonic piezoelectric linear motor design are described. A method for optimizing the geometry of the motor to maximize its mechanical output for a given electrical input is described, as is the inherent properties of the design to maximize the motors durability and utilization of the piezoelectric material. Results from testing the motor demonstrate the design and indicate a maximum speed of 2.5 cm/s with a preload of 16 g due to an applied voltage of 80 V/RMS/ at an applied current of 15 mA.
Adaptive Critic Based Neural Networks For Control-Constrained Agile Missile Control, Dongchen Han, S. N. Balakrishnan
Adaptive Critic Based Neural Networks For Control-Constrained Agile Missile Control, Dongchen Han, S. N. Balakrishnan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
We investigate the use of an `adaptive critic' based controller to steer an agile missile with a constraint on the angle of attack from various initial Mach numbers to a given final Mach number in minimum time while completely reversing its flightpath angle. We use neural networks with a two-network structure called `adaptive critic' to carry out the optimization process. This structure obtains an optimal controller through solving Hamiltonian equations. This approach needs no external training; each network along with the optimality equations generates the output for the other network. When the outputs are mutually consistent, the controller output is …
Environmental Performance Analysis Of Solid Freedom Fabrication Processes, Yanchun Luo, Zhiming Ji, Ming-Chuan Leu, R. J. Caudill
Environmental Performance Analysis Of Solid Freedom Fabrication Processes, Yanchun Luo, Zhiming Ji, Ming-Chuan Leu, R. J. Caudill
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper presents a method for analyzing the environmental performance of solid freeform fabrication (SFF) processes. In this method, each process is divided into life phases. Environmental effects of every process phase are then analyzed and evaluated based on the environmental and resource management data. These effects are combined to obtain the environmental performance of the process. The analysis of the environmental performance of SFF processes considers the characteristics of SFF technology, includes material, energy consumption, processes wastes, and disposal. Case studies for three typical SFF processes: stereolithography (SL); selective laser sintering (SLS); and fused deposition modeling (FDM) are presented …
Shell Cracking In Investment Casting With Laser Stereolithography Patterns, W. L. Yao, Ming-Chuan Leu
Shell Cracking In Investment Casting With Laser Stereolithography Patterns, W. L. Yao, Ming-Chuan Leu
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper presents an investigation of ceramic shell cracking during the burnout process in investment casting with internally webbed laser stereolithography patterns. We hypothesize that shell cracking will occur when the rupture temperature of the ceramic shell is lower than both the glass transition temperature of the pattern material and the web· link buckling temperature. The hypothesis is validated by our experimental observations which confirm the numerical predictions from our finite element analysis. This provides a basis for design of the internal web geometry of a lithography pattern and evaluation of the burnout process with such a pattern. We show …
Rapid Freezing Prototyping With Water, Wei Zhang, Ming-Chuan Leu, Zhiming Ji, Yongnian Yan
Rapid Freezing Prototyping With Water, Wei Zhang, Ming-Chuan Leu, Zhiming Ji, Yongnian Yan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Rapid Freezing Prototyping (RFP) with water is a novel solid freeform fabrication technique that can generate three-dimensional ice objects by depositing and rapidly freezing water layer by layer. The support where necessary is made of brine whose. freezing point is lower than. pure water. After building the part, the support can be removed by utilizing the melting temperature difference between brine and water. Preliminary experiments have shown that the ice patterns produced by this technique can be used for design visualization and silicone molding. This paper will present the concept and some experimental results of the RFP process as well …
Adjustable Ice Fishing Tip-Up, Ashok Midha
Adjustable Ice Fishing Tip-Up, Ashok Midha
Mechanical and Aerospace Engineering Faculty Research & Creative Works
An ice fishing tip-up includes a base frame adapted to span a hole in a layer of ice over a body of water, and carrying a mast which is extendible through the hole into the water. The mast includes a shaft fixed at its lower end to a spool of fishing line and at its upper end to a cam cylinder with a helical groove formed in its outer surface. A signal staff is spring-biased to a raised position and is movable to a lowered position received in one of the convolutions of the helical groove. A pull on the …
A Class Of Modified Hopfield Networks For Control Of Linear And Nonlinear Systems, Jie Shen, S. N. Balakrishnan
A Class Of Modified Hopfield Networks For Control Of Linear And Nonlinear Systems, Jie Shen, S. N. Balakrishnan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper presents a class of modified Hopfield neural networks (MHNN) and their use in solving linear and nonlinear control problems. This class of networks consists of parallel recurrent networks which have variable dimensions that can be changed to fit the problems under consideration. It has a structure to implement an inverse transformation that is essential for embedding optimal control gain sequences. Equilibrium solutions are discussed. Numerical results for a motivating aircraft control problem (linear) are presented. Furthermore, we formulate the state-dependent Riccati equation method (SDRE) for a class of nonlinear dynamical system and show how MHNN provides the solution. …
Cell Mapping Based Fuzzy Control Of Car Parking, Tea-Quin Kim, Ming-Chuan Leu
Cell Mapping Based Fuzzy Control Of Car Parking, Tea-Quin Kim, Ming-Chuan Leu
Mechanical and Aerospace Engineering Faculty Research & Creative Works
This paper describes the development of a near-optimal fuzzy controller for maneuvering a car in a parking lot. To generate the rules of the fuzzy controller, a cell mapping method is utilized to systematically generate near-optimal trajectories for all possible initial states in the parking lot. Based on the input-output relations of these trajectories, which represent the states and controls of the corresponding cells, a set of fuzzy rules are generated automatically. In order to result in a small number of fuzzy rules from the large amount of numerical information generated by cell mapping, grouping of trajectories is proposed and …
An Mdo-Compatible Method For Robust Design Of Vehicles, Systems, And Components, Leslie D. Liaw, Richard I. Devries, Donald L. Cronin
An Mdo-Compatible Method For Robust Design Of Vehicles, Systems, And Components, Leslie D. Liaw, Richard I. Devries, Donald L. Cronin
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A CAE simulation process was developed to quantify the variability of vehicle attributes such as safety, durability, vehicle dynamics, NVH and weight. The process was integrated with the Ford multi-function optimization (MFO) tool — MOVE (Multi-Function Optimization Visualization Environments) in order to facilitate the robust design of vehicles, systems and components. The statistics of vehicle attribute responses are computed given the statistics of the design parameters. The response surface approximation was used to simplify the input and output relationships. A variety of statistical distributions can be selected to match the statistics of the design parameters which are continuous or discrete. …
Belted Work Machine, J. J. Burckhartzmeyer, E. R. Crabb, T. F. Lehnhoff, A. L. Watson Jr.
Belted Work Machine, J. J. Burckhartzmeyer, E. R. Crabb, T. F. Lehnhoff, A. L. Watson Jr.
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A heavy duty belt laying work machine includes a frame, a driver wheel mounted in supporting relation to the frame on each lateral side thereof, an idler wheel assembly disposed on each lateral side of the frame. The idler wheel assembly includes an idler wheel and a carry-roller, each of which is rotatably connected to an idler support arm that is pivotally mounted in supporting relation to the frame. A mid-roller is disposed on each lateral side of the frame between the driver wheel and the idler wheel assembly and rotatably connected to a mid-roller support arm mounted in supporting …
Metal-Organic Chemical Vapor Deposition Of Sr-Co-Fe-O Films On Porous Substrates, C.-F. Xia, P. Atanasova, Robert W. Schwartz, T. L. Ward
Metal-Organic Chemical Vapor Deposition Of Sr-Co-Fe-O Films On Porous Substrates, C.-F. Xia, P. Atanasova, Robert W. Schwartz, T. L. Ward
Mechanical and Aerospace Engineering Faculty Research & Creative Works
Aerosol-assisted chemical vapor deposition using the b-diketonate precursors Sr(tmhd)2•2H2O, Fe(tmhd)3 and Co(tmhd)3 was investigated for depositing thin films of the mixed-conducting ceramic SrCoyFe1-yO3-d onto porous a-Al2O3 substrates. Single-phase SrCoyFe1-yO3-d perovskite films were obtained at a deposition temperature of 550°C and pressure of 15 mm Hg, whereas deposition at atmospheric pressure produced mixed-phase films. The Co/Fe elemental ratios in the films reflected those in the precursor solution, but the films were depleted in Sr. Reduced-pressure deposition provided a more uniform film morphology than atmospheric-pressure, and led to a supported film which was leak-tight to N2 flow.
Robustness Analysis Of Hopfield And Modified Hopfield Neural Networks In Time Domain, Jie Shen, S. N. Balakrishnan
Robustness Analysis Of Hopfield And Modified Hopfield Neural Networks In Time Domain, Jie Shen, S. N. Balakrishnan
Mechanical and Aerospace Engineering Faculty Research & Creative Works
A variant of the Hopfield network, called the modified Hopfield network is formulated. This network which consists of two mutually recurrent networks has more free parameters than the well-known Hopfield network. Stability analysis of this network is presented. The analysis is carried out in the time domain with an application of the Lyapunov method and robust control Lyapunov function. The current flow in the network is treated as a "control". This "controller" is shown to guarantee "a practically stabilizing control". Analysis of the Hopfield network is also included for completion.
The Effect Of A Baffle On Acoustic Radiation Directivity, Walter Eversman, Indranil Danda Roy
The Effect Of A Baffle On Acoustic Radiation Directivity, Walter Eversman, Indranil Danda Roy
Mechanical and Aerospace Engineering Faculty Research & Creative Works
An investigation is made of the effect of an artificial baffle introduced in Finite Element modeling of acoustic radiation from turbofan inlets. The purpose of the baffle is to limit the extent of the computational domain in order to maximize the efficiency of the scheme. However, the possibility exists that the baffle, if improperly oriented, will generate spurious reflections which interfere with the true radiated acoustic field. A generic example of a turbofan inlet, including typical geometry and non-uniform potential flow in and around the nacelle, is modeled with a baffle as typically introduced limiting the angular extent of the …