Engineering Physics Commons^™

Power Maximization Of A Three-Phase Hydrokinetic Turbine, Matthew Carleson

Senior Theses

As Earth`s expendable resources dwindle, the need for alternative, renewable energy sources grows. Out of this need, an old favorite source is rising in popularity: small water turbines. Water-driven turbines first began as a means for turning mills and eventually evolved into massive dams that can power whole regions. This project focused on the construction of, and testing the properties of, a small pico-hydro power turbine. By using compressed air to drive the turbine, a representation of the peak power output was measured, serving as a basis for determining the value of pico-power systems in regards to the world`s current …

Effect Of Seam-Height On Curveballs, Joseph S. Carroll

Senior Theses

The difference in seam-height between raised and flat-seam baseballs causes them to react differently when thrown by a pitcher. Altering the seam-height on the ball changes the amount of drag force on it as it travels through the air. The goal of this experiment is to measure the difference in vertical deflection between the two types of balls when pitched with curveball topspin. It was discovered that the baseball with raised-seams experiences more vertical deflection than the flat-seam ball.

Measuring Strain In Trusses, Spencer Metzsch

Senior Theses

Strain is an important quantity in engineering design and materials science that relates the deformation of a material to its original length, through a percentage. Different materials exhibit particular qualities under loading, for example the amount of strain due to a certain magnitude of force, or the amount of strain that can be borne before failure. This experiment aims to compare the relative strengths of three common truss configurations by measuring the strain in their members under loading. The Queen’s post truss was found to be the best at minimizing strain under similar loading conditions.

Available Work Rate Of A Reversible System Bounded By Constant Thermal Resistances Linked To Isothermal Reservoirs, Jim Mcgovern

Conference Papers

Exergy analysis is based on the concept of an idealized, all-enclosing reference environment that has infinite heat capacity and thermal conductivity, and is in equilibrium. The actual surroundings of a real plant such as a heat engine, a heat pump or a refrigerator may differ significantly from the ideal. First law performance parameters and second law rational efficiency are examined. The concepts of finite time thermodynamics are applied in an attempt to refine the concept of T0, the environmental reference temperature, thereby making exergy analysis more reflective of reality.

Manipulating The Mass Distribution Of A Golf Putter, Paul J. Hessler Jr.

Senior Honors Projects

Putting may appear to be the easiest but is actually the most technically challenging part of the game of golf. The ideal putting stroke will remain parallel to its desired trajectory both in the reverse and forward direction when the putter head is within six inches of the ball. Deviation from this concept will cause a cut or sidespin on the ball that will affect the path the ball will travel.

Club design plays a large part in how well a player will be able to achieve a straight back and straight through club head path near impact; specifically the …

Crystal Nucleation Of Palladium-Doped Lithium Disilicate Glass, Gregory Humble

Symposium of Student Scholars

The effect of concentration of palladium particles on crystal nucleation was investigated for lithium disilicate glass. The heterogeneous nucleation rate for 470°C and 480°C were calculated for a concentration of 0.001% palladium by weight. The DTA method of measuring nucleation and crystallization was used in this calculation.

Cost-Availability Curves For Hierarchical Implementation Of Residential Energy-Efficiency Measures, Roman Villoria-Siegert, Philip Brodrick, Kevin P. Hallinan, Robert J. Brecha

Physics Faculty Publications

Historical residential electricity data and natural gas consumption data were collected for, respectively, 1,200 and 178 residences in a small town in the USA. These data were merged with local building and weather databases, and energy consumption models were developed for each residence, revealing substantial variation in heating and cooling intensity. After estimating approximate physical building characteristics, energy profiles for each residence were calculated, and savings from adoption of the most cost-effective energy-efficiency measures for each residence were estimated. Effectively, we wish to leverage commonly available data sets to infer characteristics of building envelopes and equipment, without the need for …

Generation Of Multi-Charged Aluminum Ions From Femtosecond Laser Induced Plasma, Frederick Guy Wilson

Electrical & Computer Engineering Theses & Dissertations

Laser-induced plasma multi-charged ion (MCI) sources have gained in popularity over the last thirty years with the advent of reliable, high peak power, short temporal pulse laser systems. Utilization of laser-induced plasma MCI sources allows for production of a wide array of ion species from a variety of source target materials. In this thesis an investigation of the generation of MCis from an aluminum (Al) target source through laser-induced plasma from a femtosecond (fs) pulsed laser system is outlined and the results presented and analyzed. In order to characterize the production of the Al MCis resulting from the fs laser …

Absorption Spectroscopy Of Rubidium In An Alkali Metal Dispenser Cell And Bleached Wave Analysis, James M. Rosenthal

Theses and Dissertations

An absorption spectrum of a rubidium alkali metal dispenser (AMD) cell was obtained in order to determine the system s suitability for use in a diode pumped alkali laser (DPAL) and use in high-temperature spectroscopic studies. The AMD produced a concentration of 3.65 0.16 1010 cm-3, which is in the ideal range for Beer s Law region absorption spectroscopy, but too low to make a high-power DPAL in a 10 cm cell with a poor Q resonator. Before AMDs can be used to determine pressure broadening and shifting coefficients, issues concerning contamination and producing rubidium vapor at pressure must be …

Scaling Of An Optically Pumped Mid-Infrared Rubidium Laser, Paul J. Moran

Theses and Dissertations

An optically pumped mid-infrared rubidium (Rb) pulsed laser has been demonstrated in a heat pipe along the 6²P_3/2 - 6²S_1/2 transition at 2.730 µm and the 6²P_1/2 - 6²S_1/2 transition at 2.790 µm. The bleached limit, slope efficiency, and maximum laser output energy of the mid-IR Rb laser have been shown to scale linearly with increasing Rb density, contrary to prior laser demonstrations. A maximum output energy of 5 nJ per pulse had previously been observed before a rollover occurred in the scaling of output energy with Rb …

Efficient General Computational Method For Estimation Of Standard Atmosphere Parameters, Nihad E. Daidzic Ph.D., Sc.D.

International Journal of Aviation, Aeronautics, and Aerospace

Knowledge of standard air temperature, pressure, density, speed of sound, and viscosity as a function of altitude is essential information in aircraft design, performance testing, pressure altimeter calibration, and several other aeronautical engineering and aviation science applications. A new efficient computational method for rapid calculations of standard atmospheric parameters up to 86 orthometric km is presented. Additionally, mass and weight of each standard atmospheric layer were calculated using a numerical integration method. The sum of all fractional masses and weights represents the total mass and weight of Earth’s atmosphere. The results obtained here agree well with measurements and models of …

A Contribution Toward Better Understanding Of Overbanking Tendency In Fixed-Wing Aircraft, Nihad E. Daidzic

Journal of Aviation Technology and Engineering

The phenomenon of overbanking tendency for a rigid-body, fixed-wing aircraft is investigated. Overbanking tendency is defined as a spontaneous, unbalanced rolling moment that keeps increasing an airplane’s bank angle in steep turns and must be arrested by opposite aileron action. As stated by the Federal Aviation Administration, the overbanking tendency may lead to a loss of control, especially in instrument meteorological conditions. It was found in this study that the speed differential over wing halves in horizontal turns indeed creates a rolling moment that achieves maximum values for bank angles between 45 and 55 degrees. However, this induced rolling moment …

Electromechanical Magnetization Switching, Eugene M. Chudnovsky, Reem Jaafar

Publications and Research

We show that the magnetization of a torsional oscillator that, in addition to the magnetic moment also possesses an electrical polarization, can be switched by the electric field that ignites mechanical oscillations at the frequency comparable to the frequency of the ferromagnetic resonance. The 180° switching arises from the spin-rotation coupling and is not prohibited by the different symmetry of the magnetic moment and the electric field as in the case of a stationary magnet. Analytical equations describing the system have been derived and investigated numerically. Phase diagrams showing the range of parameters required for the switching have been obtained.

Magnetic Force Microscopy Study Of Zr2co11-Based Nanocrystalline Materials: Effect Of Mo Addition, Lanping Yue, Yunlong Jin, Wenyong Zhang, David J. Sellmyer

Nebraska Center for Materials and Nanoscience: Faculty Publications

The addition of Molybdenum was used to modify the nanostructure and enhance coercivity of rare-earth-free Zr₂Co₁₁-based nanocrystalline permanent magnets. The effect of Mo addition on magnetic domain structures of melt spun nanocrystalline Zr₁₆Co_84−xMo_x (𝑥 = 0, 0.5, 1, 1.5, and 2.0) ribbons has been investigated. It was found that magnetic properties and local domain structures are strongly influenced by Mo doping. The coercivity of the samples increases with the increase in Mo content (𝑥 ≤ 1.5). The maximum energy product (𝐵𝐻)_max increases with increasing 𝑥 from 0.5 MGOe for 𝑥 …

Effect Of Strain On Ferroelectric Field Effect In Strongly Correlated Oxide Sm0.5Nd0.5Nio3, L. Zhang, X. G. Chen, H. J. Gardner, M. A. Koten, J. E. Shield, X. Hong

Xia Hong Publications

We report the effect of epitaxial strain on the magnitude and retention of the ferroelectric field effect in high quality PbZr_0.3Ti_0.7O₃ (PZT)/3.8-4.3 nm Sm_0.5Nd_0.5NiO₃ (SNNO) heterostructures grown on (001) LaAlO₃ (LAO) and SrTiO₃ (STO) substrates. For SNNO on LAO, which exhibits a first-order metal-insulator transition (MIT), switching the polarization of PZT induces a 10 K shift in the transition temperature T_MI, with a maximum resistance change between the on and off states of Δ��/��_on ~75%. In sharp contrast, only up to 5% resistance change has …

Additional Results For "Joint Entropy Of Continuously Differentiable Ultrasonic Waveforms" [J. Acoust. Soc. Am. 133(1), 283-300 (2013)], M S. Hughes, J N. Marsh, S A. Wickline, John E. Mccarthy

Mathematics Faculty Research

Previous results on the use of joint entropy for detection of targeted nanoparticles accumulating in the neovasculature of MDA435 tumors [Fig. 7 of M. S. Hughes et al., J. Acoust. Soc. Am. 133, 283–300 (2013)] are extended, with sensitivity improving by nearly another factor of 2. This result is obtained using a “quasi-optimal” reference waveform in the computation of the joint entropy imaging technique used to image the accumulating nanoparticles.

Electrostatic Charge On Flying Hummingbirds And Its Potential Role In Pollination, Marc Badger, Victor Manuel Ortega-Jimenez, Lisa Von Ribenau, Ashley Smiley, Robert Dudley, Alexei Gruverman , Editor

Alexei Gruverman Publications

Electrostatic phenomena are known to enhance both wind- and insect-mediated pollination, but have not yet been described for nectar-feeding vertebrates. Here we demonstrate that wild Anna's Hummingbirds (Calypte anna) can carry positive charges up to 800 pC while in flight (mean ± s.d.: 66 ± 129 pC). Triboelectric charging obtained by rubbing an isolated hummingbird wing against various plant structures generated charges up to 700 pC. A metal hummingbird model charged to 400 pC induced bending of floral stamens in four plants (Nicotiana, Hemerocallis, Penstemon, and Aloe spp.), and also attracted falling Lycopodium spores at distances of < 2 mm. Electrostatic forces may therefore influence pollen transfer onto nectar-feeding birds.

Effect Of Strain On Ferroelectric Field Effect In Strongly Correlated Oxide Sm0.5Nd0.5Nio3, Le Zhang, Chen, H. J. Gardner, Mark A. Koten, Jeffrey E. Shield, Xia Hong

Nebraska Center for Materials and Nanoscience: Faculty Publications

We report the effect of epitaxial strain on the magnitude and retention of the ferroelectric field effect in high quality PbZr_0.3Ti_0.7O₃ (PZT)/3.8–4.3 nm Sm_0.5Nd_0.5NiO₃ (SNNO) heterostructures grown on (001) LaAlO₃ (LAO) and SrTiO₃ (STO) substrates. For SNNO on LAO, which exhibits a first-order metal-insulator transition (MIT), switching the polarization of PZT induces a 10K shift in the transition temperature TMI, with a maximum resistance change between the on and off states of ΔR = R_on ~75%. In sharp contrast, only up to 5% resistance change has been …

Development Of Srf Cavity Tuners For Cern, K. Artoos, R. Calaga, O. Capatina, T. Capelli, F. Carra, L. Dassa, N. Kuder, R. Leuxe, P. Minginette, W. Venturini Delsolaro, G. Villiger, C. Zanoni, P. Zhang, S. Verdu-Andrés, B. Xiao, G. Burt, J. Delayen, Hyekyoung Park, T. Jones, N. Templeton

Physics Faculty Publications

Superconducting RF cavity developments are currently on-going for new accelerator projects at CERN such as HIE ISOLDE and HL-LHC. Mechanical RF tuning systems are required to compensate cavity frequency shifts of the cavities due to temperature, mechanical, pressure and RF effects on the cavity geometry. A rich history and experience is available for such mechanical tuners developed for existing RF cavities. Design constraints in the context of HIE ISOLDE and HL-LHC such as required resolution, space limitation, reliability and maintainability have led to new concepts in the tuning mechanisms. This paper will discuss such new approaches, their performances and planned …

Control Of Synchrotron Radiation Effects During Recirculation With Bunch Compression, D. R. Douglas, S. V. Benson, R. Li, Y. Roblin, C. D. Tennant, Geoffrey A. Krafft, Balŝa Terzić, C. -Y. Tsai

Physics Faculty Publications

Studies of beam quality preservation during recirculation * have been extended to generate a design of a compact arc providing bunch compression with positive momentum compaction ** and control of both incoherent and coherent synchrotron radiation (ISR and CSR) effects using the optics balance methods of diMitri et al.***. In addition, the arc/compressor generates very little micro-bunching gain. We detail the beam dynamical basis for the design, discuss the design process, give an example solution, and provide simulations of ISR and CSR effects. Reference will be made to a complete analysis of micro-bunching effects ****.