Mechanical Engineering Commons^™

Thermodynamic Aspect And Diffusion Model On Interdiffusion Of Laminate Structure, Shing-Hoa Wang

Journal of Marine Science and Technology

A non-uniform system such as microsegregation, heterogeneous microstructure and multiple-layer deposition of thin films, always exists in the engineering materials and the electronic materials for solid state devices. As a consequence of interdiffusion under high temperature exposure, The dynamical changes of composition profiles and vacancies could lead to materials in earlier failure and reduce the life time of the component. Several theoretical fundamentals have been proposed on different aspects, including(1) the void formation at the steepest concentration gradient:(2) thermodynamic view points of excess vacancy flux;(3) the model of interdiffusion for dynamic composition profile change; and(4) stress gradient induced strain enhanced …

Study Of Photoelectrochemical Cells For Hydrogen Production By Water Splitting Using Cigs2/Cds Heterojunction, Florida Solar Energy Center, Neelkanth Dhere

FSEC Energy Research Center®

Study of Photoelectrochemical Cells for Hydrogen Production by Water Splitting Using CIGS2/CdS Heterojunction

Industry Guide To Selecting The Best Residential Window Options For The Florida Climate, Florida Solar Energy Center, Ross Mccluney

FSEC Energy Research Center®

It used to be said that windows are little more than holes in the insulation. It is true to some extent that poorly insulated and drafty windows in certain climates defeat the purpose of wall insulation. However, modern high performance windows are almost as good as opaque insulated wall sections, at least in terms of total energy savings over long periods of time. In some cases, they can be shown to actually out-perform insulated walls. Of course, they have the priceless additional benefits of providing views to the outdoors and natural daylight illumination indoors important issues of quality and comfort. …

Prediction Of Airfoil Stall In Icing Conditions Using Wing Surface Pressures, Erik Pederson

Masters Theses

This thesis presents work on a Normalized Lift Coefficient instrumentation system that predicts airfoil stall in icing conditions. The system uses four surface pressures, measured aft of the ice formation, from which the aircraft's normalized lift coefficient is determined. The pressure port locations were selected such that the calibration algorithm remains nearly constant as the leading edge ice shape and thickness change. Data collected in the Western Michigan University Wind Tunnel is presented for three ice formations varying in both shape and thickness. The ice and no ice conditions were compared and a set of four ports was found that …

Small Below-Endurance-Limit Cycle Damage Contributions In Variable Sequence Loading For 2024-T351 Aluminum Alloy, Christopher M. Ngiau

Masters Theses

It is a common practice in industry today to totally discard the presence of small below-endurance/fatigue limit cycles while calculating damage accumulation using the Palmgren-Miner rule. However, it was experimentally found in a number of studies that small cycles with stress amplitudes below the fatigue/endurance limit do in fact contribute significantly to the damage accumulation in all types of materials. There was a need to investigate cases where small cycles would only be present for a certain percentage of the material's life. An experimental study was done on 2024- T351 aluminum alloy. Loading was done in low and high cyclic …

Modeling Of A Meat Cooking Process For On-Line Monitoring And Control, Oralia Garcia

Theses and Dissertations - UTB/UTPA

A heat transfer model is developed to predict cooking time of meat patties given the initial temperature of meat, oven temperature, and meat properties to monitor and control a cooking process on-line. Experiments were performed to find the cause of variability in cooked weight and raw temperature effects in forming and final cooked temperature. Advanced charting techniques concluded that only common causes of variability were present in the process. Thermal conductivity experiments were performed to determine the thermal conductivity of meat (k), which was compared with the properties of meat published in literature to validate the experiment. Oven design analysis …

Optimal Design Of Beams Undergoing Harmonic Bending And Torsion Using Finite Elements, Arnoldo Garcia

Theses and Dissertations - UTB/UTPA

In this study, the objective is to determine the natural frequency of an Euler-Bernoulli beam with an intermediate mass and inertial component. The beam is studied with fixed and relaxed end conditions. The beam is also modeled with an intermediate support. The models are then compared with an approximate closed form solution for the natural frequency. Results show that the closed form equation is within 2% percent when compared to the exact natural frequency equation.

The beam is modeled with a finite element software. The goal is to minimize the weight of a beam structure subject to harmonic excitation. Results …

An Experimental Study Of Low Speed Open Cavity Flows, Abraham J. Meganathan

Masters Theses

The experimental work is part of an ongoing study aimed at understanding and controlling of cavity instabilities by passive or active steady or unsteady fluid injection. An experimental setup has been designed to quantitatively visualize the flow-field inside the cavity for varying relative dimensions (L/D ratios of 2.0, 2.67, 3.5 and 4.5, W/D of 3.33) at low subsonic speeds ranging from 55 ft/sec to 214 ft/sec using Particle Image Velocimetry (PIV).

The results showed that PIV could provide instantaneous velocity and other flow field data inside and above the cavity. The quality of data is good and may be used …

Multi-Diameter Vise Clamp And Collet Jaw, Lloyd D. Snell

Lloyd D Snell

A machine vise has incorporated into it a pair of collet jaws that allows for the machining of top surfaces and ends of a held part. The collet jaws are secured to each of the clamping blocks on the machine vise. The collet jaws include at least one collet pocket shaped into the inside surface of each collet jaw. The collet pockets are designed to receive collet pads which are shaped to hold a generally cylindrical part with varying diameters. By having more than one collet pocket within each collet jaw, several different sizes of collet pads can be utilized …

A Growth Mixture Theory For Cartilage, Stephen M. Klisch, Robert L. Sah, Anne Hoger

Mechanical Engineering

In this paper we present a model of growth for cartilaginous tissues in which there exists a saturated solid matrix composed of multiple constituents that may grow and remodel independently of each other. Klisch and Hoger recently developed a general theory of volumetric growth for a mixture of ν-1 growing elastic materials and an inviscid fluid, which included a treatment of two special types of internal constraints that are relevant to cartilage. Here, that theory is specialized to construct a cartilage growth model. This theory allows the constituents of the solid matrix to grow independently of each other, and can …

A Comparison Of Two Actuators For A Semi-Active Helmholtz Resonator, Charles Birdsong, Clark J. Radcliffe

Mechanical Engineering

Two electro-mechanical actuators are examined for a semi-active Helmholtz resonator acoustic device. The device is used to reflect narrow band noise back to the source in an acoustic duct. The controller and actuator are used to tune the system on-line allowing optimum performance over a range of operating conditions. Actuator. dynamics play an important role in the controller design and the operation of the device. Two variations of an electro-mechanical actuator are considered here. The first uses a dual voice coil speaker with local feedback compensation and the second uses the same speaker without the compensation. It is shown that …

Development And Validation Of A Pedestrian Lower Limb Non-Linear 3-D Finite Element Model, Peter Schuster, Gopal Jayaraman

Mechanical Engineering

Lower limb injury is becoming an increasingly important concern in vehicle safety for both occupants and pedestrians. To enable vehicle manufacturers to better understand the biomechanical effects of design changes, it is deemed beneficial to employ a biomechanically fidelic finite element model of the human lower limb.

The model developed in this study includes long bones (tibia, fibula, femur) and flat bone (patella) as deformable bodies. The pelvis and foot bones are modeled as rigid bodies connected to the femur and tibia/fibula via rotational spring-dashpots. The knee is defined by scanned bone surface geometry and is surrounded by the menisci, …

Surface Extrapolation Length And Director Structures In Confined Nematics, Nikolai V. Priezjev, Robert A. Pelcovits

Mechanical and Materials Engineering Faculty Publications

We report the results of Monte Carlo simulations of the Lebwohl-Lasher model of nematic liquid crystals confined to cylindrical cavities with homeotropic anchoring. We show that the ratio of the bulk to surface couplings is not in general equal to the corresponding parameter K/W used in elastic theory (where K is the Frank elastic constant in the one-constant approximation and W is the surface anchoring strength). By measuring the temperature dependence of K/W (which is equivalent to the surface extrapolation length) we are able to reconcile the results of our simulations as well as others with the predictions of elastic …

Executive Summary: Comparative Evaluation Of The Impact Of Roofing Systems On Residential Cooling Energy Demand In Florida, Florida Solar Energy Center, John Sherwin

FSEC Energy Research Center®

Roof and attic thermal performance exert a powerful influence on cooling energy use in Florida homes. Unshaded residential roofs are heated by solar radiation causing high afternoon attic air temperatures. The large influence on cooling is due to increased ceiling heat transfer as well as heat gains to the duct systems which are typically located in the attic space (Figure E-1). The Florida Power and Light Company and the Florida Solar Energy Center instrumented six side-by-side Habitat homes in Ft. Myers, Florida with identical floor plans and orientation, R-19 ceiling insulation, but with different roofing systems designed to reduce attic …

Contributions Of Proximal And Distal Moments To Axial Tibial Rotation During Walking And Running, T. L. Bellchamber, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

The purpose of this study was to determine the cause and effect relationship between tibial internal rotation and pronation of the foot during walking and heel–toe running. This would allow predictions of orthotic effectiveness in reducing knee pain related to excessive internal tibial rotation. Kinematic and force plate data were collected from twenty subjects performing ten running and ten walking trials across a force plate. Using a least-squares algorithm, attitude matrices for each segment in each frame were obtained and the angular velocity vector of the tibia was calculated. The intersegmental moment at the ankle was calculated from ground reaction …

Tibiocalcaneal Kinematics Of Barefoot Versus Shod Running, Alex Stacoff, Benno M. Nigg, Christoph Reinschmidt, Antonie J. Van Den Bogert, Arne Lundberg

Mechanical Engineering Faculty Publications

Barefoot running kinematics has been described to vary considerably from shod running. However, previous investigations were typically based on externally mounted shoe and/or skin markers, which have been shown to overestimate skeletal movements. Thus, the purpose of this study was to compare calcaneal and tibial movements of barefoot versus shod running using skeletal markers. Intracortical bone pins with reflective marker triads were inserted under standard local anesthetic into the calcaneus and tibia of five healthy male subjects. The subjects ran barefoot, with a normal shoe, with three shoe soles and two orthotic modifications. The three-dimensional tibiocalcaneal rotations were determined using …

Evaluating The Impacts Of Uncontrolled Air Flow And Hvac Performance Problems On Florida's Commercial And Institutional Buildings - Final Report, Florida Solar Energy Center, James Cummings

FSEC Energy Research Center®

Twenty commercial and institutional buildings located in central Florida were tested for uncontrolled air flow and cooling system problems. Tested buildings were selected based on three criteria; 1) buildings with large exhaust fans, 2) buildings with leaky ceilings, and 3) education buildings. They ranged in size from a 650 square foot portable classroom to a 50,000 square foot elementary school, with an average floor area of 6518 square feet.

Diagnostic inspection and testing was performed in each building to identify problems related to uncontrolled air flow or HVAC system or control problems. The tests were performed to characterize or identify …

Fish Cage Physical Scale Modeling, Michael J. Palczynski

Master's Theses and Capstones

Scale model tests were completed in the University of New Hampshire (UNH) Wave/Tow tank to determine the movements and forces on two different fish cage models. The results of the testing were used to validate a finite element analysis and also were scaled up to that of a full sized, deployed fish cage used for aquaculture purposes.

The first model was a “skeleton” cage (without nets) rectangular in shape. This model was moored submerged in front of a viewing window and subjected to various regular waves. The motions were then recorded nonintrusively by means of an optical system acting through …

Validation Of Energygauge® Usa Using The Hers Bestest Procedure, Florida Solar Energy Center, Philip Fairey

FSEC Energy Research Center®

This report presents results from the testing and validation of the EnergyGauge USA home energy rating software conducted using the HERS BESTEST procedures. The results show that EnergyGauge USA is an excellent and verifiable simulation program that is capable of meeting all national requirements for home energy rating software tools.

Developing An Implementation Plan For The Idaho Msri Partnership Workshop Summary - Final Report, Florida Solar Energy Center, Jennifer Szaro

FSEC Energy Research Center®

Workshop conducted to develop an implementation plan for the Idaho Million Solar Roofs Initiative.

Oct 2000, Tractor Museum

Museum Planning and Development Documents

Open House Pedestrian Door Installed Collection of Hand Tools

The Hers Rating Method And The Derivation Of The Normalized Modified Loads Method, Florida Solar Energy Center, Philip Fairey

FSEC Energy Research Center®

This paper provides much of the historical background surrounding the contentious development of a national, uniform rating method for rating the energy-efficiency of homes. A full derivation of the most recently adopted rating method, the Normalized Modified Loads Method, is provided in detail and the issues and events leading up to the development of each of the succeeding methods are described.

Ever since the inclusion of Home Energy Rating Systems in the 1992 Energy Policy Act, the most contentious issue associated with them has been the development of a uniform rating method. To date, four succeeding methods have been proposed: …

Developing An Implementation Plan For The Montana Msri Coalition Workshop Summary - Final Report, Florida Solar Energy Center, Jennifer Szaro

FSEC Energy Research Center®

Workshop was conducted to develop and implementation plan for the Montana Million Solar Roofs Initiative.

Preparation Of Mesoporous Sno2-Sio2 Composite As Electrodes For Lithium Batteries, Fanglin Chen, Zhong Shi, Meilin Liu

Faculty Publications

Mesoporous SnO₂–SiO₂ composite stable up to 600 °C with a BET surface area of 350 m² g^-1 and an average pore size of 3.4 nm is successfully prepared, which exhibits promising cycling properties as anodes for lithium batteries

Preparation Of Mesoporous Yttria-Stabilized Zirconia (Ysz) And Ysz-Nio Using A Triblock Copolymer As Surfactant, Fanglin Chen, Meilin Liu

Faculty Publications

Mesoporous yttria-stabilized zirconia (YSZ) and YSZ-NiO have been prepared for the first time using Pluronic P103 as a structure-directing agent and inorganic chlorides as precursors in a nonaqueous medium. After being fired at 500°C for 2 h, mesostructured YSZ has a BET surface area of about 146 m² g^-1, with an average pore size of 3.8 nm, while mesostructured YSZ-NiO has a BET surface area of about 108 m² g^-1, with an average pore size of 4.5 nm.

Plastic Solder Paste Stencil For Surface Mount Technology, Christopher K. Wong, Daniel Waldorf

Industrial and Manufacturing Engineering

Solder paste masks or stencils are an integral part of the manufacturing process for surface mount PCBs. This study examines the feasibility of a process for rapid creation of a solder paste stencil using thermoplastic material. CNC laser cutting of the stencil geometry is replacing traditional use of chemical etching on metal sheets to produce stencils. Laser cutting has been used to improve process speed, accuracy, and cost. This research attempts to continue to simplify and reduce costs in the stencil making process by proposing as the stencil material a common thermoplastic that can be cut easily and quickly using …

Global Projects Prepare Wpi Students For The 21st Century, William W. Durgin, Donald N. Zwiep

Office of the Provost Scholarship

The WPI project based curriculum, which emphasizes discovery based learning are an alternative to the traditional information transfer process, has proved successful in delivering global engineering education. More than 25% of the learning process of the students is integrated into two formal projects, the Major Qualifying Project (MQP) which is designed as a capstone for professional technical competence and the Interactive Qualifying Project (IQP) which relates science and technology to societal concerns and student needs. Both the MQP and IQP may be completed on- or off-campus. Currently, over 50% of the graduating class will have completed one of the projects …

Statistical Representation Of A Spray As A Point Process, Shankar Subramaniam

Shankar Subramaniam

The statistical representation of a spray as a finite point process is investigated. One objective is to develop a better understanding of how single-point statistical information contained in descriptions such as the droplet distribution function ~ddf!, relates to the probability density functions ~pdfs! associated with the droplets themselves. Single-point statistical information contained in the droplet distribution function ~ddf! is shown to be related to a sequence of single surrogate-droplet pdfs, which are in general different from the physical single-droplet pdfs. It is shown that the ddf contains less information than the fundamental single-point statistical representation of the spray, which is …

The Influence Of Orthotic Devices And Vastus Medialis Strength And Timing On Patellofemoral Loads During Running, R. R. Neptune, I. C. Wright, Antonie J. Van Den Bogert

Mechanical Engineering Faculty Publications

Objective. To use a musculoskeletal model and simulation of running to examine: (1) the influence of two commonly prescribed treatments for patellofemoral pain (vastus medialis oblique strengthening and orthoses) and (2) the functional significance of timing differences between vastus medialis oblique and vastus lateralis on lateral patellofemoral joint loads.

Design. A three-dimensional musculoskeletal model of the lower extremity was used to simulate running at 4 m/s.

Background. Repetitive and excessive joint loading is often associated with overuse injuries that require clinical treatments to reduce pain and restore function. Affecting one in four runners, patellofemoral pain is one …

The Effects Of Patch Properties On The Debonding Behavior Of Patched Beam-Plates, Anette M. Karlsson

Mechanical Engineering Faculty Publications

The debonding characteristics of patched structures are investigated in this study by means of an analytical model. In particular, the effects the lay-up sequence and edge tapering of a carbon-reinforced epoxy patch, as well as the beveling of an aluminum patch, have on the initiation, stability, and extent of the debonding are considered. The results presented show that both the degree of edge-tapering and the patch properties must be carefully selected in order to optimize the patched structure. It is also shown that when designing a patched system, it is important to model the correct boundary and load conditions to …