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1995

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Articles 1 - 30 of 124

Full-Text Articles in Mechanical Engineering

Investigation Of Dynamic Friction In Lubricated Surfaces, Hanuman Rachoor Dec 1995

Investigation Of Dynamic Friction In Lubricated Surfaces, Hanuman Rachoor

Dissertations

The research reported in this dissertation is concerned with the development of friction models for lubricated contacts. A few analytical models have been developed to investigate the friction under dynamic velocity conditions. In this study, two different tribological situations such as conformal and non-conformal contacts have been chosen. Friction modeling covers boundary, mixed and full fluid film friction regions. A new theory based on the elastic properties of the surface materials, and fluid film properties of the lubricant at the contact has been developed to determine the dynamic friction in boundary, mixed and full hydrodynamic lubrication regions. In the full ...


Design For Quality Manufacturability Analysis Of Total Nonconformity Damaged Parts, Samir R. Gami Dec 1995

Design For Quality Manufacturability Analysis Of Total Nonconformity Damaged Parts, Samir R. Gami

Theses

The competitive nature of modern manufacturing, demands that innovative approaches be applied in order to have a competitive edge. Shortening the product development cycle, the period from initial design to full production, is a priority for most manufacturers today. The DFQM methodology addresses the issue of quality manufacturability (QM) - the likelihood that defects will occur during manufacture of a product in a standard plant. As a consequence, DFQM helps to shorten the design cycle time. The DFQM architecture identifies a variety of design factors and variables that influence specific defects. This process of influencing defects can be described by error ...


Design And Analysis Of Environmentally Safe Cooling Systems For Machine Tools, Haiping Xu Dec 1995

Design And Analysis Of Environmentally Safe Cooling Systems For Machine Tools, Haiping Xu

Theses

Many cooling systems of metal cutting and both their advantages and disadvantages have been reviewed. The cutting forces' relationships, stress distribution, energy consumption and heat generation of orthogonal processes are discussed. A two-dimensional finite element model has been developed to design and analyze a new proposed cooling device, which comes from the idea of "A Novel Cooling Device" proposed by Billatos et al. First, a thermal calculation is completed to compare the temperature difference between two different shapes of coiled pipe. Then, three different cutting conditions, which were considered in the experiments by Childs et al, are conducted under three ...


Implementation Of A Three-Dimensional Non-Intrusive Particle Tracking System, Vivek Gupta Dec 1995

Implementation Of A Three-Dimensional Non-Intrusive Particle Tracking System, Vivek Gupta

Theses

A Three-Dimensional Non-Intrusive Particle Tracking System has been developed at NJIT's Particle Technology Center to provide experimental results for validating theories being developed in the field of Particle Technology. The system utilizes the principle of magnetic induction between several high-frequency miniature transmitters mounted inside a sphere and a set of receiving loop antennae mounted outside the experimental apparatus. Basic theories and algorithms for the tracking system have already been developed. The focus of this thesis is to make the tracking system more accurate, reliable and user-friendly and to apply it to the study of vibrated beds and chute flows ...


Real Time Control Of Nonlinear Dynamic Systems Using Neuro-Fuzzy Controllers, Amitava Jana Dec 1995

Real Time Control Of Nonlinear Dynamic Systems Using Neuro-Fuzzy Controllers, Amitava Jana

Dissertations

The problem of real time control of a nonlinear dynamic system using intelligent control techniques is considered. The current trend is to incorporate neural networks and fuzzy logic into adaptive control strategies. The focus of this work is to investigate the current neuro-fuzzy approaches from literature and adapt them for a specific application. In order to achieve this objective, an experimental nonlinear dynamic system is considered. The motivation for this comes from the desire to solve practical problems and to create a test-bed which can be used to test various control strategies. The nonlinear dynamic system considered here is an ...


Structural Characterization Of Aluminum Films Deposited On Sputtered-Titanium Nitride/ Silicon Substrate By Metalorganic Chemical Vapor Deposition From Dimethylethylamine Alane, Xiaodong Li, Byoung-Youp Kim, Shi-Woo Rhee Dec 1995

Structural Characterization Of Aluminum Films Deposited On Sputtered-Titanium Nitride/ Silicon Substrate By Metalorganic Chemical Vapor Deposition From Dimethylethylamine Alane, Xiaodong Li, Byoung-Youp Kim, Shi-Woo Rhee

Faculty Publications

Alfilmsdeposited on sputtered‐TiN/Si substrate by metalorganic chemical vapor deposition(MOCVD) from dimethylethylamine alane (DMEAA) were characterized using x‐ray diffraction(XRD),Auger electron spectroscopy(AES),atomic force microscopy(AFM), and transmission electron microscopy (TEM). The TiN filmsputtered on the Si has a preferred orientation along the growth direction with the 〈111〉 of the film parallel to the Si〈111〉. Sputtering of the TiN film on the Si induced strains at the interface. The TiN/Si interface is flat while the Al/TiN interface is rough. There exist many dislocations at the Al/TiN interface. The Al2O ...


Study On Passive And/Or Active Vibration Control For Flexible Structures, Qinghua Chen Dec 1995

Study On Passive And/Or Active Vibration Control For Flexible Structures, Qinghua Chen

FIU Electronic Theses and Dissertations

The purpose of this research is to present new methods of active and passive vibration control for flexible structures. The study includes: 1) passive viscoelastic damping treatment; 2 ) active vibration control using layered shape memory alloy (SMA); 3) combined application of viscoelastic damping treatment and SMA; 4) experiments.

In order to maximize damping and save weight of the structure and cost, a partially covered double sandwich cantilever beam model has been presented. It is shown that the double sandwich beam is better than single sandwich beam for some conditions. To take into account of end loads effect of elastic structures ...


Design Of A Wheelchair With Legs For People With Motor Disabilities, Parris Wellman, Venkat Krovi, Vijay Kumar, William Harwin Dec 1995

Design Of A Wheelchair With Legs For People With Motor Disabilities, Parris Wellman, Venkat Krovi, Vijay Kumar, William Harwin

Departmental Papers (MEAM)

A proof-of-concept prototype wheelchair with legs for people with motor disabilities is proposed, with the objective of demonstrating the feasibility of a completely new approach to mobility. Our prototype system consists of a chair equipped with wheels and legs, and is capable of traversing uneven terrain and circumventing obstacles. The important design considerations, the system design and analysis, and an experimental prototype of a chair are discussed. The results from the analysis and experimentation show the feasibility of the proposed concept and its advantages.


Dynamic Pulse Buckling Of Columns With Viscous Damping, Murli Kadandale Dec 1995

Dynamic Pulse Buckling Of Columns With Viscous Damping, Murli Kadandale

Master's Theses

This is a study of dynamic pulse buckling of columns with viscous damping. The differential equations of motion were obtained using the Bemoulli-Navier hypothesis. The effects of axial and rotary inertia were included in the analysis. The Voigt-Kelvin model for a viscoelastic material is used. The Finite Difference Method was employed to solve the differential equations of motion. First columns without geometrical imperfections were studied, and a correlation between the damping modulus and the more familiar damping ratio was obtained. Then beams with initial geometrical imperfection were studied. A suitable dynamic buckling criterion was defined. It was observed that viscous ...


An Investigation Of Turbulent Taylor-Couette Flow Using Laser Doppler Velocimetry In A Refractive Index Matched Facility, Joseph C. Parker Dec 1995

An Investigation Of Turbulent Taylor-Couette Flow Using Laser Doppler Velocimetry In A Refractive Index Matched Facility, Joseph C. Parker

Master's Theses

Turbulent Taylor-Couette flow between an annulus formed by two concentric cylinders with dead end walls is comprised of complex patterns of vortices. An experimental apparatus was designed to provide refractive index matching between the annulus and working fluid. Optical access was maintained through three sides of the annulus and one end wall. An aqueous solution of sodium iodide was formulated to match the refractive index of the Plexiglas annulus. Laser Doppler Velocimetry was used to measure the three components of velocity and turbulence intensity throughout a planar section in the annulus. The annulus dimensions were: ƞ= 0.672, d = 15 ...


The Effect Of Rotor Wake/Exit Guide Vane Interaction On The Total Pressure Losses In An Airfoil Cascade, Aaron Mosebach Dec 1995

The Effect Of Rotor Wake/Exit Guide Vane Interaction On The Total Pressure Losses In An Airfoil Cascade, Aaron Mosebach

Master's Theses

Computational simulations have been performed to study the effects of unsteady rotor wakes on the total pressure losses and the boundary layer characteristics in a compressor cascade. In the numerical simulations, transitional and turbulent flow conditions were modeled at design and off-design inlet flow angles, and for varying rotor wake widths and wake velocity deficits.

First, simulations were performed in the absence of rotor wakes at the inlet of the EGV (Exit Guide Vane) cascade. Second, simulations were performed for different wake width and wake velocity deficit values at the inlet of the EGV cascade. The majority of the numerical ...


Audio Signal Processor, Jeffrey J. Vallier Nov 1995

Audio Signal Processor, Jeffrey J. Vallier

Iowa State University Patents

An audio signal processor capable of both sampling and audio processing external audio signals is disclosed. The audio signal processor can sample anaudio signal and store it in a fixed store in a two function memory for later playback or manipulation. The processor can also audio process external signals in real time by splitting an incoming signal into two parts; processing one part such that it is time delayed and/or pitch shifted, or both, with respect to the unaltered part; and recombining the processed part and the unaltered part to achieve time delay effects such as flanging, chorus and ...


1995 Strategic Plan For Museum, Tractor Museum Nov 1995

1995 Strategic Plan For Museum, Tractor Museum

Museum Planning and Development Documents

Check from Mr. Gerst Letter from Dr. Omtvedt Plan for Renovation Decision to Replace Roof Estimate from Landscaping


Malt Drying Model Verification For Efficiency Improvement, John David Kribs Nov 1995

Malt Drying Model Verification For Efficiency Improvement, John David Kribs

Dissertations and Theses

The aim of this work has been to minimize the thermal energy required to dry malt in deep beds while maintaining malt quality, and without increasing the drying time more than one hour. Malt drying usually takes place in deep bed (. 7-1 m) driers by forcing hot air through the bed. Measurements of inlet and outlet relative humidity, temperature, and airflow at a drier at Great Western Malting Company's Vancouver, Washington facility were made to find average moisture content versus time. The measurements were used to develop a wetted surface model of a malt bed. However, the model was ...


Ultrasonic Radiative Transfer In Polycrystalline Media: Effects Of A Fluid–Solid Interface, Joseph A. Turner, Richard L. Weaver Nov 1995

Ultrasonic Radiative Transfer In Polycrystalline Media: Effects Of A Fluid–Solid Interface, Joseph A. Turner, Richard L. Weaver

Faculty Publications from the Department of Engineering Mechanics

In previous derivations of the ultrasonic radiative transfer equation (URTE) for the modeling of multiply scattered diffuse ultrasound in polycrystalline media, the boundary conditions appropriate to experiments performed in a water bath were not used. In the present work, this fluid–solid boundary condition is discussed as it applies to the URTE. An interpolation scheme is developed that is consistent with the discrete ordinates method used for the solution of the URTE. Steady-state and time-dependent results are presented for the solution of the URTE with a fluid–solid boundary condition. The steady-state results show that diffusive behavior is exhibited nearer ...


A Psychological Perspective On Service Segmentation Models: The Significance Of Accounting For Consumers' Perceptions Of Waiting And Service, Ziv Carmon, J. George Shanthikumar, Tali F. Carmon Nov 1995

A Psychological Perspective On Service Segmentation Models: The Significance Of Accounting For Consumers' Perceptions Of Waiting And Service, Ziv Carmon, J. George Shanthikumar, Tali F. Carmon

Industrial and Manufacturing Engineering

We examine how service should be divided and scheduled when it can be provided in multiple separate segments. We analyze variants of this problem using a model with a conventional function describing the waiting cost, that is modified to account for some aspects of the psychological cost of waiting in line. We show that consideration of the psychological cost can result in prescriptions that are inconsistent with the common wisdom of queuing theorists derived according to the conventional approach (e.g., equal load assignments). More generally, our intention in this paper is to illustrate that aspects of the psychological cost ...


Modeling Multiple Reactive Scalar Mixing With The Generalized Iem Model, Kuochen Tsai, Rodney O. Fox Nov 1995

Modeling Multiple Reactive Scalar Mixing With The Generalized Iem Model, Kuochen Tsai, Rodney O. Fox

Rodney O. Fox

An outstanding feature of the amplitude mapping closure is its ability to relax an arbitrary initial probability density function (PDF) to a Gaussian PDF asymptotically. Due to the difficulties in computing either the analytical or numerical solution, the mapping closure has never been applied to multiple scalars with finite reaction rates. In this work, the generalized IEM (GIEM) model is combined with the mapping closure to model the molecular mixing terms in the PDF balance equation. The GIEM model assumes a linear relationship between the rates of change of the reactive scalars and an inert scalar (shadow scalar) during the ...


Laminar Natural Convection In A Discretely Heated Cavity: Ii—Comparisons Of Experimental And Theoretical Results, Theodore J. Heindel, F. P. Incropera, S. Ramadhyani Nov 1995

Laminar Natural Convection In A Discretely Heated Cavity: Ii—Comparisons Of Experimental And Theoretical Results, Theodore J. Heindel, F. P. Incropera, S. Ramadhyani

Theodore J. Heindel

Three-dimensional numerical predictions and experimental data have been obtained for natural convection from a 3 × 3 array of discrete heat sources flush-mounted on one vertical wall of a rectangular cavity and cooled by the opposing wall. Predictions performed in a companion paper (Heindel et al., 1995a) revealed that three-dimensional edge effects are significant and that, with increasing Rayleigh number, flow and heat transfer become more uniform across each heater face. The three-dimensional predictions are in excellent agreement with the data of this study, whereas a two-dimensional model of the experimental geometry underpredicts average heat transfer by as much as 20 ...


Laminar Natural Convection In A Discretely Heated Cavity: I—Assessment Of Three-Dimensional Effects, Theodore J. Heindel, S. Ramadhyani, F. P. Incropera Nov 1995

Laminar Natural Convection In A Discretely Heated Cavity: I—Assessment Of Three-Dimensional Effects, Theodore J. Heindel, S. Ramadhyani, F. P. Incropera

Theodore J. Heindel

Two and three-dimensional calculations have been performed for laminar natural convection induced by a 3 × 3 array of discrete heat sources flush-mounted to one vertical wall of a rectangular cavity whose opposite wall was isothermally cooled. Edge effects predicted by the three-dimensional model yielded local and average Nusselt numbers that exceeded those obtained from the two-dimensional model, as well as average surface temperatures that were smaller than the two-dimensional predictions. For heater aspect ratios Ahtr ≲ 3, average Nusselt numbers increased with decreasing Ahtr . However, for Ahtr ≳ 3, the two and three-dimensional predictions were within 5 percent of each other and ...


Design, Development, And Testing Of An Automated Window Sliade Controller, Greg R. Luecke, J. Slaughter Nov 1995

Design, Development, And Testing Of An Automated Window Sliade Controller, Greg R. Luecke, J. Slaughter

Mechanical Engineering Publications

An approach to the design of active window shades is developed to control the direct solar gain through a window. Using simple actuation hardware and sensors, a control strategy is presented that automatically adjusts window shades to save HVAC energy by controlling direct solar radiation passing through a window. The control algorithm is based on a simple approach that admits direct light in the winter and blocks the direct light in the summer, while providing shade adjustment that affords maximum visibility through the window. Cloudy skies or indirect sun result in horizontal placement of the shades, and the shades close ...


Vibration As An Aid In Robotic Peg-In-Hole Assembly, Hsin-Te Liao Oct 1995

Vibration As An Aid In Robotic Peg-In-Hole Assembly, Hsin-Te Liao

Dissertations

This dissertation presents an analytical and experimental investigation of vibration assisted engagement for parts mating. A dynamic model of assembly is established by using Lagrange's equation for impact to derive impact equations for a robotic manipulator in peg-in-hole assembly. The model can be used to analyze part motion and contact force in the mating of parts by robots. The impact equations of a SCARA robot are derived using this model and utilized to investigate how robot configuration, insertion speed, chamfer angle, coefficient of restitution and other system parameters affect impulsive force and departure angle in the assembly of a ...


Particle Deposition On Surfaces In A Divergent Channal Flow, Ding Sun Oct 1995

Particle Deposition On Surfaces In A Divergent Channal Flow, Ding Sun

Dissertations

Particle trajectory and deposition of two phase gas-solid flows in a convergent or divergent two-dimensional channel are investigated numerically in a wide range of parameters. For the fluid phase, a two dimensional, incompressible laminar fluid flow is considered in the analysis. The particle phase is a diluted suspension. The effects of inertia, gravity, viscous force and electrostatic image force are included in the computational model.

Both convergent and divergent channel flow are solved by the finite element method based on the software FIDAP. The flow separations will appear in a divergent channel and their separation positions are obtained in the ...


Chute Flow Experiments, Yahong Zhang Oct 1995

Chute Flow Experiments, Yahong Zhang

Theses

The objective of this thesis is to study the behavior of granular materials flowing down an inclined chute using three diagnostic techniques under different chute inclination angles and chute floor conditions. The three methods are: (1) tracking the motion of single particle within the mass in a noninvasive manner using a transmitting sphere and antenna receiving system, (2) scale mass flow rate measurement, and (3) high speed camera system to obtain flow velocity measurements.

For these purposes, an experimental setup has been completed and a set experiments has been performed.


The Effect Of Liquid Gallium On Plastics, Vivek P. Dwivedi Oct 1995

The Effect Of Liquid Gallium On Plastics, Vivek P. Dwivedi

Theses

As part of a joint effort by Cornell University and NJIT to find a replacement for mercury as a pressuring medium for P-V-T devices, we investigated the effect of liquid gallium on four thermoplastics: two semi-crystalline ( high density polyethylene and polypropylene ) and two amorphous ( polystyrene and polymethylmethacrylate ). Test specimens were covered with liquid gallium and held in vacuum oven at temperatures close to their melting points for up to two weeks. Change in weight after treatment with gallium was measured, along with tensile testing and particle analysis using dispersion x-ray spectroscopy. The results are compared with specimens treated under identical ...


Auditing & Measuring The Need For Flexibility In A Manufacturing Facility, Kartika-Sari Stroman Oct 1995

Auditing & Measuring The Need For Flexibility In A Manufacturing Facility, Kartika-Sari Stroman

Theses

Flexible manufacturing was created out of the need for facilities to be able to efficiently respond to changes in their environment so as to build a competitive advantage. Flexible manufacturing (FM) is currently viewed as a way for facilities to be able to introduce and produce multiple products quickly and more efficiently. In this research we will present some new tools to help managers address the changes that are affecting the facility.

An audit was developed to help system designers identify the changes that are impacting the facilities. The audit provides the opportunity to understand the changes that are occurring ...


Process For The Formation Of Wear- And Scuff-Resistant Carbon Coatings, Gerard W. Malaczynski, Xiaohong Qiu, Joseph V. Mantese, Alaa A. Elmoursi, Aboud H. Hamdi, Blake P. Wood, Kevin C. Walter, Michael Nastasi Oct 1995

Process For The Formation Of Wear- And Scuff-Resistant Carbon Coatings, Gerard W. Malaczynski, Xiaohong Qiu, Joseph V. Mantese, Alaa A. Elmoursi, Aboud H. Hamdi, Blake P. Wood, Kevin C. Walter, Michael Nastasi

Mechanical & Materials Engineering Faculty Publications

A process for forming an adherent diamond-like carbon coating on a workpiece of suitable material such as an aluminum alloy is disclosed. The workpiece is successively immersed in different plasma atmospheres and subjected to short duration, high voltage, negative electrical potential pulses or constant negative electrical potentials or the like so as to clean the surface of oxygen atoms, implant carbon atoms into the surface of the alloy to form carbide com pounds while codepositing a carbonaceous layer on the surface, bombard and remove the carbonaceous layer, and to thereafter deposit a generally amorphous hydrogen-containing carbon layer on the surface ...


Buckling Analysis And Optimum Design Of Multidirectionally Stiffened Composite Curved Panel, Navin R. R. Jaunky Oct 1995

Buckling Analysis And Optimum Design Of Multidirectionally Stiffened Composite Curved Panel, Navin R. R. Jaunky

Mechanical & Aerospace Engineering Theses & Dissertations

Continuous filament grid-stiffened structure is a stiffening concept that combines structural efficiency and damage tolerance. However, buckle resistant design optimization of such structures using a finite element method is expensive and time consuming due to the number of design parameters that can be varied. An analytical optimization procedure which is simple, efficient and supports the preliminary design of grid-stiffened structures for application to combined loading cases is needed.

An analytical model for a general grid-stiffened curved panel is developed using an improved smeared theory with a first-order, shear-deformation theory to account for transverse shear flexibilities and local skin-stiffener interaction effects ...


An Experimental Investigation Of Wall Cooling Effects On Hypersonic Boundary Layer Stability In A Quiet Wind Tunnel, Alan E. Blanchard Oct 1995

An Experimental Investigation Of Wall Cooling Effects On Hypersonic Boundary Layer Stability In A Quiet Wind Tunnel, Alan E. Blanchard

Mechanical & Aerospace Engineering Theses & Dissertations

One of the primary reasons for developing quiet tunnels is for the investigation of high-speed boundary-layer stability and transition phenomena without the transition-promoting effects of acoustic radiation from tunnel walls. In this experiment, a flared-cone model under adiabatic- and cooled-wall conditions was placed in a calibrated, 'quiet' Mach 6 flow and the stability of the boundary layer was investigated using a prototype constant-voltage anemometer. The results were compared with linear-stability theory predictions and good agreement was found in the prediction of second-mode frequencies and growth. In addition, the same 'N=10' criterion used to predict boundary-layer transition in subsonic, transonic ...


Chp And Energy Conservation, Jim Mcgovern Sep 1995

Chp And Energy Conservation, Jim Mcgovern

Articles

The principles of the use of 'combined heat and power' (CHP) for the achievement of fuel energy conservation, minimisation of environmental impact and economic advantage are explained. A distinction is made between the two types of outputs: heat and work. It is argued that an efficiency value that is defined as the sum of the heat and work outputs divided by the energy of the fuel used is not very meaningful. An alternative, rational, efficiency is explained. It is concluded that CHP is an option to be considered where both heating and power are required, but is not a general ...


A Virtual Reality Environment For Synthesizing Spherical Four-Bar Mechanisms, Scott W. Osborn, Judy M. Vance Sep 1995

A Virtual Reality Environment For Synthesizing Spherical Four-Bar Mechanisms, Scott W. Osborn, Judy M. Vance

Mechanical Engineering Conference Presentations, Papers, and Proceedings

This paper describes the development of a virtual reality environment which facilitates the design of spherical four-bar mechanisms. A short discussion of spherical mechanism design theory and computer-aided mechanism design is followed by a description of the virtual environment and the development and operation of the SphereVR program. The virtual environment allows the user to naturally interact with the input data and specify the design parameters while operating in a three-dimensional environment. We see this development as a logical extension of existing graphics-based spatial design software. The need for a three-dimensional design space is driven by the difficulty in specifying ...