Engineering Commons^™

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. …

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 …

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

Lester F. Larsen Tractor 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 …

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 …

Evaluation Of Resources And Energy Systems At Dry Tortugas National Park, Addendum Report, Florida Solar Energy Center, James Dunlop

FSEC Energy Research Center®

The objectives of this report are to identify opportunities for increasing efficiency, reducing costs and improving environmental quality by implementing conservation measures and renewable energy systems in park operations. Information in this report was derived from a site survey conducted on April 4-6, 2000 by personnel from the National Park Service (NPS), U.S. Department of Energy (DOE), Sandia National Laboratories (SNL), Oak Ridge National Laboratory (ORNL) and Florida Solar Energy Center (FSEC). It builds on earlier site assessments and reports developed in 1989 and 1997 by FSEC under contract to DOE and SNL

Energy Efficient Design For Florida Educational Facilities, Florida Solar Energy Center, Janet Mcilvaine

FSEC Energy Research Center®

This manual addresses energy efficiency options for new educational facilities in Florida. The recommendations may not be valid when considered outside Florida's hot humid climate or for purposes other than new construction.

Construction funds spent on new construction heavily outweigh (67%) those spent on retrofit, as reported in an annual statistical analysis published by American School and University (September 1992). The comprehensive survey showed that construction funds for new educational facilities nationwide have risen for eight consecutive years, and no region has experienced more growth than the Southeast. Currently, funds spent on energy services (excluding capital outlay, salaries, benefits, and …

A Dynamic Optimal Trajectory Generator For Cartesian Path Following, Edward Red

Faculty Publications

This paper considers a dynamic and adaptive trajectory generator for negotiating paths using S-curves. Applying constant jerk transitions between the constant acceleration and deceleration periods of the trajectory, the trajectory will optimally transition to the desired speed setting. Optimal is defined to be the minimum time to transition from the current speed to the set speed for the move segment when jerk and acceleration are limited. The S-curve equations will adapt to instantaneous changes in speed setting and path length. An integrated motion planner will determine allowable speeds and transitional profiles based on the remaining move distance.

Improving Doe-2'S Resys Routine: User Defined Functions To Provide More Accurate Part Load Energy Use And Humidity Predictions, Florida Solar Energy Center, Hugh Henderson, Jr.

FSEC Energy Research Center®

In hourly energy simulations, it is important to properly predict the performance of air conditioning systems over a range of full and part load operating conditions. An important component of these calculations is to properly consider the performance of the cycling air conditioner and how it interacts with the building. This paper presents improved approaches to properly account for the part load performance of residential and light commercial air conditioning systems in DOE-2. First, more accurate correlations are given to predict the degradation of system efficiency at part load conditions. In addition, a user-defined function for RESYS is developed that …

Factors Influencing Space Heat And Heat Pump Efficiency From A Large-Scale Residential Monitoring Study, Florida Solar Energy Center, Matthew Bouchelle

FSEC Energy Research Center®

Since Florida utilities often experience their system peak during the state's few cold mornings, understanding influences on space heat performance is important to controlling demand. Analysis of heat pump impacts on system load in a large scale monitoring study have shown large levels of strip heat being used during the winter morning peak. The implied coefficient of performance of heat pumps during the system peak hour was only 1.30. Also, analysis of the total seasonal space heat has shown that the implied Heating Season Performance Factor (HSPF) of heat pump homes is only 4.4 Btu/W rather than the 6-8 Btu/W …

On Thermal Buckling Of Patched Beam-Plates, Anette M. Karlsson, W. J. Bottega

Mechanical Engineering Faculty Publications

The behavior of uniformly heated plates is considered for the situation where a patch is adhered over a region of the structure. A variational formulation results in a self-consistent set of equations and conditions, which governs the response of the system. The nonlinear problems are solved analytically, yielding exact results within the context of the mathematical model employed. A stability criterion is established for the class of problems considered, based on the second variation of the potential energy of the composite structure, and issues of stability are assessed in this context. Three non-dimensional parameters that characterize the response of the …

Hidden Power Drains: Trends In Residential Heating And Cooling Fan Watt Power Demand, Florida Solar Energy Center, John Proctor

FSEC Energy Research Center®

This paper compiles power draw, air flow, and static pressure measurements of residential air handlers taken during nine separate field tests of space conditioning systems in Arizona, California, Florida, Nevada, and Canada. The field tests show that air handler devices do not meet basic performance standards and that the interactions between components combine to further degrade overall system efficiency. The findings support conclusions from previous research in Canada that called for a systems approach to improving air handler efficiency. This study reports that fan power consumption in U.S. air conditioners is about 40% higher than estimates used in the DOE …

Determination And Improvement Of Building Speed In Rapid Freeze Prototyping, Wei Zhang, Guanghua Sui, Ming-Chuan Leu

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Rapid freeze prototyping (RFP) is a solid freeform fabrication process that builds an ice part by rapidly freezing water in a layer by layer manner. One advantage of this process is the ability to build ice parts faster than other SFF processes. The factors that affect the speed of contour building and interior filling in RFP are identified. The influence of these factors is analyzed through heat transfer and material flow analyses. A model based on heat transfer analysis is proposed to determine the maximum achievable speed of contour building under stable conditions. Experiments are conducted to validate the performance …

Laser Additive Manufacturing Process Planning And Automation, Jun Zhang, Jianzhong Ruan, Frank W. Liou

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents a Laser Additive Manufacturing Process Planning (LAMPP) being developed at the University of Missouri-Rolla. The off-line planning recognizes difficult-to-build features from an STL file, selects optimal part orientation and building directions based on the skeleton information of the object geometry, and optimizes the sub-process sequences for deposition and machining. During the optimization of the subpart building processes, collaboration between the deposition process planner and the machining process planner is needed to check the deposition availability and machinability. As a result, tool paths for both the laser head and the machining head are automatically generated.