Engineering Commons^™

Performance Of Four Near Zero Energy Homes: Lessons Learned, Florida Solar Energy Center, Carlos Colon

FSEC Energy Research Center®

While the idea of a zero or near zero energy home is well understood, the actual performance of the structure can be different than expected. High performance homes necessitate increasingly complex envelope, HVAC, water heating, and appliance systems, and successful designs rely on proper function and feedback from those systems to achieve low-energy goals. This paper presents measured data on four near zero energy homes located in Florida that are a part of the U.S. DOE Building America program. The monitored data are compared to both a benchmark model and the prototype computer simulations. By examining the submetered energy data, …

Silicon Oxide Micromodule Capacitors, W. B. Nowak, J. J. O'Connor

Welville B. Nowak

Silicon oxide capacitors have been developed on micromodule wafers (0.310-in. sq. with three termination notches per side). Each microelement contains 1, 2, 3, or 4 capacitors with values of 1120 and 560, 180, 100 and 68 pf per capacitor, respectively. The 1120 pf capacitor is double layered. In addition to the general requirements of microelements and micromodules, some of the more important specifications these capacitors must meet are: dissipation factor (DF) not exceeding 0.015, insulation resistance (IR) at 50 volts exceeding 10,000 megohms (25°C) and 750 megohms (125°c), 50 WVDC and 150 volts dielectric withstanding voltage (DWV), Δ C not …

Structural And Magnetic Characterization Of Amorphous Gd₂Fe₁₄B Thin Films, S. E. Bushnell, P. C. Dorsey, W. B. Nowak, C. Vittoria

Welville B. Nowak

Thin amorphous films of nominal composition Gd₂Fe₁₄B were fabricated on Si (100) substrates using ion‐beam sputtering for the purpose of establishing their structural and magnetic properties at room temperature. X‐ray‐diffraction scans performed on as‐deposited and annealed films revealed an amorphous structure. The as‐deposited saturation magnetization was found to be 8101 G at room temperature suggesting ferrimagnetic ordering with anti‐parallel coupling similar to other heavy rare earth‐transition metal systems. Results from in‐plane and perpendicular ferromagnetic resonance experiments conducted at 9.108 GHz showed the films to be inhomogeneous. This was evident from the presence of two in‐plane resonance lines and spin‐wave spectra …

The Measurement Of Magnetostriction Constants Of Thin Films Using Planar Microwave Devices And Ferromagnetic Resonance, S. E. Bushnell, W. B. Nowak, S. A. Oliver, C. Vittoria

Welville B. Nowak

In this paper we introduce a new technique for measuring the saturation magnetostriction constant (λs) for isotropic polycrystalline thin films. The technique makes use of nonresonant planar microwave structures together with a novel stressing mechanism to induce a shift in the resonant field of a magnetic thin film as measured by a ferromagnetic resonance (FMR) experiment. Measurement of the shift induced by a uniaxial stress allows for determination of λs via a magnetic resonance analysis. Either a slotline device or coplanar waveguide (CPW) was used as the source of the microwave excitation field depending upon the orientation of the dc …

Magnetic And Structural Investigation Of Heat Treated Ion Beam Sputtered Amorphous Co₇₄Fe₆B₁₅Si₅ Films, V. G. Harris, S. A. Oliver, W. B. Nowak, C. Vittoria, R. J. Culbertson, W. T. Elam, K. H. Kim

Welville B. Nowak

As-deposited and annealed specimens of ion beam sputtered amorphous Co₇₄Fe₆B₁₅Si₅ thin films were examined to explore the correlation between changes in magnetic properties and atomic structure. Specimens were characterized magnetically, by traditional ac and dc techniques and structurally, via conversion-electron extended x-ray absorption fine structure analysis. Results show significant ordering of the higher order atomic shells around the transition metal ions well below the crystallization temperature. This ordering evolves into a body- centered-cubic configuration around both the Co and Fe ions. Increases in nearest neighbor peak positions in the EXAFS Fourier transforms were observed to correlate with increasing annealing temperatures. …

Magnetic And Microwave Properties Of Ion-Beam-Sputtered Amorphous Feₓco₈₀₋ₓb₁₅Si₅ Films, V. G. Harris, S. A. Oliver, W. B. Nowak, C. Vittoria

Welville B. Nowak

Magnetically soft amorphous films of FeₓCo₈₀₋ₓB₁₅Si₅ (x = 0, 6, 23, 40, 70, 80) were ion beam sputter deposited onto fused quartz for static and microwave magnetic characterization. Films ranged in thickness from 220 to 260 nm and were deposited at rates of 0.1-0.2 nm/s. Saturation magnetization, coercivity, and loop squareness values were extracted from hysteresis loops generated by a vibrating sample magnetometer. Ferromagnetic resonance measurements were taken using a 9.5-GHz cavity with the applied magnetic field both parallel and perpendicular to the plane of the film, yielding values for the g factor, anisotropy field, effective magnetization, and linewidth. Well …

Phonon Wave-Packet Simulations Of Ar/Kr Interfaces For Thermalrectification, Nick A. Roberts, D. G. Walker

Nick Roberts

The frequency and direction dependence of transmission coefficients at interfaces was investigated theoretically. The interfaces are formed by having two Lennard-Jones materials differing in mass and interatomic potential equally divided at the center of an fcc lattice system. A single frequency wave-packet is generated at one end of the system and allowed to propagate through the system until all interactions with the interface are complete. The transmission coefficient is then calculated by comparing the energy of the packet that is transmitted with the original wave-packet. Results show a difference in transmission when the wave-packet originates from opposite sides.

Florida Weatherization Training - Quarterly Report (October 2010-December 2010), Florida Solar Energy Center, Neil Moyer

FSEC Energy Research Center®

The weatherization training for the State of Florida Dept of Community Affairs continues at the Florida Solar Energy Center's Training Facility. Progress for the sixth three months of the contract included a five day classroom training on October 18-22 (17 students) and in-field evaluations (16 students).

Effective Ionic Conductivity Of A Novel Intermediate-Temperature Mixed Oxide-Ion And Carbonate-Ion Conductor, Xue Li, Guoliang Xiao, Kevin Huang

Faculty Publications

A systematic investigation on the effective ionic conductivity (σ_m) of a novel intermediate-temperature mixed oxide-ion and carbonate-ion conductor MOCC consisting of a ceria phase and a carbonate phase is reported. The study explicitly shows that the observed remarkable temperature-dependent σ_m is primarily the result of softening/melting of the carbonate phase as the physical state of the carbonate phase transforms from solid, softened to molten. Differential scanning calorimetry analysis complements the understanding of the observed electrical behavior by revealing temperatures of melting and solidification in agreement with the onset temperatures of σ_m. In addition, the …

Scanning Laser Registration And Structural Energy Density Based Active Structural Acoustic Control, Daniel Alan Manwill

Theses and Dissertations

To simplify the measurement of energy-based structural metrics, a general registration process for the scanning laser doppler vibrometer (SLDV) has been developed. Existing registration techniques, also known as pose estimation or position registration, suffer from mathematical complexity, instrument specificity, and the need for correct optimization initialization. These difficulties have been addressed through development of a general linear laser model and hybrid registration algorithm. These are applicable to any SLDV and allow the registration problem to be solved using straightforward mathematics. Additionally, the hybrid registration algorithm eliminates the need for correct optimization initialization by separating the optimization process from solution selection. …

Active Noise Control Of A Two-Fan Exhaust-Mounted Array Using Near-Field Control Sources And Error Sensors, Ryan Leonard Rust

Theses and Dissertations

Multiple fans are sometimes used in an array configuration to cool various types of electronic equipment. In addition to adding another noise source, using two fans with closely spaced blade passage frequencies (BPF) can create an annoying beat frequency. A two fan array with each fan having a different BPF was considered. The fans were theoretically modeled at the BPF and first harmonics. Each fan has two acoustic paths to the far field. Thus, each fan was modeled as a two source array. The first control configuration consisted of one control filter using six control sources and six error sensors …

A Comparative Verification Of Forecasts From Two Operational Solar Wind Models, Donald C. Norquist, Warner C. Meeks

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The solar wind (SW) and interplanetary magnetic field (IMF) have a significant influence on the near‐Earth space environment. In this study we evaluate and compare forecasts from two models that predict SW and IMF conditions: the Hakamada‐Akasofu‐Fry (HAF) version 2, operational at the Air Force Weather Agency, and Wang‐Sheeley‐Arge (WSA) version 1.6, executed routinely at the Space Weather Prediction Center. SW speed (V_sw) and IMF polarity (Bpol) forecasts at L1 were compared with Wind and Advanced Composition Explorer satellite observations. Verification statistics were computed by study year and forecast day. Results revealed that both models’ mean Vsw are …

Joining Polycrystalline Cubic Boron Nitride And Tungsten Carbide By Partial Transient Liquid Phase Bonding, Grant O. Cook Iii

Theses and Dissertations

Friction stir welding (FSW) of steel is often performed with an insert made of polycrystalline cubic boron nitride (PCBN). Specifically, MS80 is a grade of PCBN made by Smith MegaDiamond that has been optimized for the FSW process. The PCBN insert is attached to a tungsten carbide (WC) shank by a compression fitting. However, FSW tools manufactured by this method inevitably fail by fracture in the PCBN. Permanently bonding PCBN to WC would likely solve the fracturing problem and increase the life of PCBN FSW tools to be economically viable. Partial transient liquid phase (PTLP) bonding, a process used to …

Modeling And Testing Of Dna Motion For Nanoinjection, Regis Agenor David

Theses and Dissertations

A new technique, called nanoinjection, is being developed to insert foreign DNA into a living cell. Such DNA transfection is commonly used to create transgenic organisms vital to the study of genetics, immunology, and many other biological sciences. In nanoinjection, DNA, which has a net negative charge, is electrically attracted to a micromachined lance. The lance then pierces the cell membranes, and the voltage on the lance is reversed, repelling the DNA into the cell. It is shown that DNA motion is strongly correlated to ion transport through a process called electrophoresis. Gel electrophoresis is used to move DNA using …

Optimization Strategy For Resonant Mass Sensor Design In The Presence Of Squeeze Film Damping, Chengzhang Li, Michele H. Miller

Michigan Tech Publications

This paper investigates the design optimization of an electrostatically actuated microcantilever resonator that operates in air. The nonlinear effects of electrostatic actuation and air damping make the structural dynamics modeling more complex. There is a need for an efficient way to simulate the system behavior so that the design can be more readily optimized. This paper describes an efficient analytical approach for determining the optimum design for a microcantilever resonant mass sensor. One simple case is described. The sensor design is a square plate that is coated with a functional polymer and attached to the substrate with folded leg springs. …

Moving Ground Target Tracking In Urban Terrain Using Air/Ground Vehicles, Timothy Mclain, Randal W. Beard, Mark Owen, Huili Yu

Faculty Publications

In this paper, we present a framework for tracking a moving target in urban environments using UAVs in cooperation with UGVs. The framework takes into account occlusions between the sensor and the target. The target state is modeled using the dynamic occupancy grid and the target motion model is built using a second-order Markov chain. Based on the target occupancy grid, we design the path planning algorithm to maneuver the UAV and the UGV to configurations where they can detect the target with high probability. Simulation results show the framework is successful in solving the target tracking problem in urban …

Identifying Potential Applications For Lamina Emergent Mechanisms And Evaluating Their Suitability For Credit-Card-Sized Products, Nathan Bryce Albrechtsen

Theses and Dissertations

Lamina emergent mechanisms (LEMs) are a maturing technology that is prepared for commercial implementation into new products. LEMs are defined by three functional characteristics; they (1) are compliant, (2) are fabricated from planar materials, and (3) emerge from a flat initial state. Advantages, design challenges, and design tools are described for each of the functional characteristics. Opportunities for LEMs are discussed, namely disposable LEMs, novel arrays of LEMs, scaled LEMs, LEMs with surprising motion, shock absorbing LEMs, and deployable LEMs. Technology push product development processes were employed to select applications for LEMs. LEM technology was characterized. In a LEM workshop, …

Design Of A Near-Constant Force Spring For Orthopedic Implants, Christopher Hartman, Paul Rotarius

Honors Theses

The design and testing of a spring assembly for the attachment of an orthopedic implant is presented. The assembly is intended to supply a constant compressive force of approximately 800 lb. at the bone-implant interface, while exhibiting insensitivity to changes in the displacement of the clamping device. This near-constant force will aid in-growth of bone tissue at the implant surface. This constant compressive force was ultimately not attained due to the packaging dimensions and materials available. However, significant improvement was made upon the current design in use by lowering the spring constant around 800 lb.

The final assembly fits in …

Flow Vision For Autonomous Underwater Vehicles Via An Artificial Lateral Line, Nam Nguyen, Douglas L. Jones, Yingchen Yang, Chang Liu

Mechanical Engineering Faculty Publications and Presentations

Most fish have the capability of sensing flows and nearby movements even in dark or murky conditions by using the lateral line organs. This enables them to perform a variety of underwater activities, such as localizing prey, avoiding predators, navigating in narrow spaces, and schooling. To emulate this capability for Autonomous Underwater Vehicles, we developed an artificial lateral line using an array of Micro-Electro-Mechanical-Systems (MEMS) flow sensors. The signals collected via the artificial lateral line are then processed by an adaptive beamforming algorithm developed from Capon's method. The system produces 3D images of source locations for different hydrodynamic activities, including …

Automated Tool Design For Complex Free-Form Components, Kevin G. Foster

Theses and Dissertations

In today's competitive manufacturing industries, companies strive to reduce manufacturing development costs and lead times in hopes of reducing costs and capturing more market share from early release of their new or redesigned products. Tooling lead time constraints are some of the more significant challenges facing product development of advanced free-form components. This is especially true for complex designs in which large dies, molds or other large forming tools are required. The lead time for tooling, in general, consists of three main components; material acquisition, tool design and engineering, and tool manufacturing. Lead times for material acquisition and tool manufacture …

Optimization Design Of Electrodes For Anode-Supported Solid Oxide Fuel Cells Via Genetic Algorithm, Junxiang Shi, Xingjian Xue

Faculty Publications

Porous electrode is the critical component of solid-oxide fuel cells (SOFCs) and provides a functional material backbone for multi-physicochemical processes. Model based electrode designs could significantly improve SOFC performance. This task is usually performed via parameter studies for simple case and assumed property distributions for graded electrodes. When nonlinearly coupled multiparameters of electrodes are considered, it could be very difficult for the model based parameter study method to effectively and systematically search the design space. In this research, the optimization approach with a genetic algorithm is demonstrated for this purpose. An anode-supported proton conducting SOFC integrated with a fuel supply …

The Development Of A Phase Locked Wind Turbine Blade Finite Element Model To Predict Loads And Deflections During Fatigue Testing, Kyle Freeman

Master's Theses - Daytona Beach

Full scale blade testing provides blade manufacturers with quantitative data in order to assess blade design, manufacturing and durability. Structural testing is a requirement in order to design reliable blades, and to develop a further understanding of the dynamics involved in a modern turbine blade. Blade tests can be conducted in either a single axis or dual axis configurations. Historically, fatigue testing has been performed by utilizing forced displacement systems. These systems do not allow for the load phase angle to be controlled, and the maximum load application in the edge and flap directions are allowed to vary. The PhLEX …

The Development Of An Adaptive Control System For A Phase-Locked Excitation (Phlex) Method For Advanced Wind Turbine Blade Fatigue Testing, William Michael Haupfear

Master's Theses - Daytona Beach

The National Renewable Energy Laboratory's (NREL) National Wind Technology Center (NWTC) provides the means necessary for advanced wind turbine blade testing. To improve on the current testing methods, a new testing method is being developed using the existing dual-axis fatigue testing capabilities in conjunction with another actuator to provide a phase-locked excitation method with adaptive algorithms and advanced control system strategies. This testing method will provide a more representative loading of the blade for fatigue testing as compared to loading seen in the field. The control system will integrate the MTS software and controller with a supervisory controller, programmed in …

Geometry-Dependent Oxygen Diffusion Flux And Limiting Current Density Of The Cathode In A Cathode-Supported Solid Oxide Fuel Cell, Kevin Huang, James L. Shull

Faculty Publications

An analysis is performed on the diffusion of oxygen through tubular porous cathode substrates having several different geometries. It is shown that the flux of oxygen as it diffuses through these different substrate geometries can be explicitly expressed by a general analytical form with a unique geometric factor for each type of substrate geometry. Experimental measurements of the geometry-independent term, oxygen diffusivity, were conducted for two representative geometries: cylindrical and triangular tubes. These measurements show good agreement between samples with similar porosities and thus favorably support the oxygen flux equations presented. Formulations for the limiting current density were also derived …

Energetics And Kinetics Of Dislocation Initiation In The Stressed Volume At Small Scales, Tianlei Li

Doctoral Dissertations

Instrumented nanoindentation techniques have been widely used in characterizing mechanical behavior of materials in small length scales. For defect-free single crystals under nanoindentation, the onset of elastic-plastic transition is often shown by a sudden displacement burst in the measured load-displacement curve. It is believed to result from the homogeneous dislocation nucleation because the maximum shear stress at the pop-in load approaches the theoretical strength of the material and because statistical measurements agree with a thermally activated process of homogeneous dislocation nucleation. For single crystals with defects, the pop-in is believed to result from the sudden motion of pre-existing dislocations or …

Piedras Blancas Clock Works, Andrew James, Andrew Jupin, Matt Weber

Mechanical Engineering

In 1875, the Piedras Blancas Lighthouse was built to warn ships sailing the California coast of the hazards of the rocky shore. In 1949 a fierce storm damaged the top portion of the lighthouse and the eight ton cast iron and brass assembly had to be replaced by a much lighter piece that still served the purpose of warning oncoming vessels. The former top portion came to rest in downtown Cambria and is still there today, enclosed in a glass room to be observed by visitors and townspeople. Today, the Piedras Blancas Light station is cared for by the Bureau …

Adapted Recumbent Bike, Kurtis Mundell, Dane Tiemeier, Laura Yakuma, Darius Yu

Mechanical Engineering

The adapted recumbent project was to redesign a disabled veteran’s recumbent bicycle. The main areas of concern were the crank pedal, chain tension, braking and steering system, and ergonomics. Since the customer is an avid biker, this bike will be used often, so the design is based on the ease of repair and replacement. The crank system was redesigned to a lightweight, adjustable part with chain clearance and high strength. The chain tension was improved by replacing the existing single idler wheel/chain tube system with a dual idler wheel system. The dual idler has a titanium sprocket in one of …

Anomalous Loss Of Toughness Of Work Toughened Polycarbonate, Shawn E. Meagher

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Glassy polymers such as polycarbonate (PC) can be toughened through compressive plastic deformation. The increase in toughness is substantial, showing as much as a fifteen fold increase in the amount of dissipated energy during failure for samples compressed to 50% plastic strain. This toughness increase can be reversed through thermal aging at temperatures below the glass transition temperature (T_g = 147°C).

The combined effect of plastic compression and thermal aging has been studied using Charpy, Single Edge Notch Bending (SENB), and Compact Tension (CT) tests. The tests mapped the response of samples cut along different orientations relative to the …

Hybrid Nanomanufacturing Process For High-Rate Polymer Nanofiber Production, Chad T. Peterson

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

Nanotechnology and nanomaterials have the potential to revolutionize existing and create entirely new industries. Unique physical, mechanical, chemical, and biological properties of nanomaterials have been extensively documented in the last two decades. However, most nanomaterials are discontinuous in nature, creating problems with their processing and manipulation into devices and raising health concerns. Continuous nanofibers represent an emerging class of nanomaterials with critical advantages to applications. Continuous nanofibers are readily produced by electrospinning process comprising spinning polymer solutions in high electric fields. Electrospinning is a very economic top-down nanomanufacturing process that has been used to produce ultrafine continuous nanofibers from several …

Development And Characterization Of Shock Tubes For Laboratory Scale Blast Wave Simulation, Aaron D. Holmberg

Department of Engineering Mechanics: Dissertations, Theses, and Student Research

The prevalence of traumatic brain injury (TBI) in American soldiers exposed to a blast wave has created an urgent need to better understand the effects of blast wave insult to the head. Developing techniques that can experimentally simulate well controlled blast waves in a laboratory environment is a critical component of the research efforts towards this goal. For this work, a 4-in. cylindrical uniform shock tube and a nonuniform shock tube combining a 4-in. cylindrical gas driver with a 9-in. square driven section have been developed. The hosting laboratory, gas handling system, multichannel data acquisition systems, and the related network …