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Disaggregating Longer-Term Trends From Seasonal Variations In Measured Pv System Performance, Chibuisi Chinasaokwu Okorieimoh, Brian Norton, Michael Conlon 2024 Technological University Dublin

Disaggregating Longer-Term Trends From Seasonal Variations In Measured Pv System Performance, Chibuisi Chinasaokwu Okorieimoh, Brian Norton, Michael Conlon

Articles

Photovoltaic (PV) systems are widely adopted for renewable energy generation, but their performance is influenced by complex interactions between longer-term trends and seasonal variations. This study aims to remove these factors and provide valuable insights for optimising PV system operation. We employ comprehensive datasets of measured PV system performance over five years, focusing on identifying the distinct contributions of longer-term trends and seasonal effects. To achieve this, we develop a novel analytical framework that combines time series and statistical analytical techniques. By applying this framework to the extensive performance data, we successfully break down the overall PV system output into …


Numerical Study Of Owls' Leading-Edge Serrations, Asif Shahriar Nafi, Nikolaos Beratlis, Elias Balaras, Roi Gurka 2023 Coastal Carolina University

Numerical Study Of Owls' Leading-Edge Serrations, Asif Shahriar Nafi, Nikolaos Beratlis, Elias Balaras, Roi Gurka

Physics and Engineering Science

Owls' silent flight is commonly attributed to their special wing morphology combined with wingbeat kinematics. One of these special morphological features is known as the leading-edge serrations: rigid miniature hook-like patterns found at the primaries of the wings' leading-edge. It has been hypothesized that leading-edge serrations function as a passive flow control mechanism, impacting the aerodynamic performance. To elucidate the flow physics associated with owls' leading-edge serrations, we investigate the flow-field characteristic around a barn owl wing with serrated leading-edge geometry positioned at 20° angle of attack for a Reynolds number of 40 000. We use direct numerical simulations, where …


Characterization Of Interlayer Laser Shock Peening During Fused Filament Fabrication Of Polylactic Acid (Pla), Fabien Denise 2023 University of Nebraska-Lincoln

Characterization Of Interlayer Laser Shock Peening During Fused Filament Fabrication Of Polylactic Acid (Pla), Fabien Denise

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

The field of additive manufacturing (AM) has gained a significant amount of popularity due to the increasing need for more sustainable manufacturing techniques and the adaptive development of complex product geometries. The problem is that AM parts routinely exhibit flaws or weaknesses that affect functionality or performance. Over the years, surface treatments have been developed to compensate certain flaws or weaknesses in manufactured products. Combining surface treatments with the modularity of additive manufacturing could lead to more adaptable and creative improvements of product functions in the future. The current work evaluates the feasibility of pursuing a new research axis in …


Directional Microwave Emission From Femtosecond-Laser Illuminated Linear Arrays Of Superconducting Rings, Thomas J. Bullard, Kyle Frische, Charlie Ebbing, Stephen J. Hageman, John Morrison, John Bulmer, Enam A. Chowdury, Michael L. Dexter, Timothy J. Haugan, Anil K. Patniak 2023 Air Force Research Laboratory

Directional Microwave Emission From Femtosecond-Laser Illuminated Linear Arrays Of Superconducting Rings, Thomas J. Bullard, Kyle Frische, Charlie Ebbing, Stephen J. Hageman, John Morrison, John Bulmer, Enam A. Chowdury, Michael L. Dexter, Timothy J. Haugan, Anil K. Patniak

Faculty Publications

We examine the electromagnetic emission from two photo-illuminated linear arrays composed of inductively charged superconducting ring elements. The arrays are illuminated by an ultrafast infrared laser that triggers microwave broadband emission detected in the 1–26 GHz range. Based on constructive interference from the arrays a narrowing of the forward radiation lobe is observed with increasing element count and frequency demonstrating directed GHz emission. Results suggest that higher frequencies and a larger number of elements are achievable leading to a unique pulsed array emitter concept that can span frequencies from the microwave to the terahertz (THz) regime.


Impact Of Silicon Ion Irradiation On Aluminum Nitride-Transduced Microelectromechanical Resonators, David D. Lynes, Joshua Young, Eric Lang, Hengky Chandrahalim 2023 Air Force Institute of Technology

Impact Of Silicon Ion Irradiation On Aluminum Nitride-Transduced Microelectromechanical Resonators, David D. Lynes, Joshua Young, Eric Lang, Hengky Chandrahalim

Faculty Publications

Microelectromechanical systems (MEMS) resonators use is widespread, from electronic filters and oscillators to physical sensors such as accelerometers and gyroscopes. These devices' ubiquity, small size, and low power consumption make them ideal for use in systems such as CubeSats, micro aerial vehicles, autonomous underwater vehicles, and micro-robots operating in radiation environments. Radiation's interaction with materials manifests as atomic displacement and ionization, resulting in mechanical and electronic property changes, photocurrents, and charge buildup. This study examines silicon (Si) ion irradiation's interaction with piezoelectrically transduced MEMS resonators. Furthermore, the effect of adding a dielectric silicon oxide (SiO2) thin film is …


Hydroxyapatite-Based Coatings On Silicon Wafers And Printed Zirconia, Antoine Chauvin 2023 University of Nebraska-Lincoln

Hydroxyapatite-Based Coatings On Silicon Wafers And Printed Zirconia, Antoine Chauvin

Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research

Dental surgery needs a naturally attract implant design that can ensure both osseointegration and soft tissue integration. Hydroxyapatite (HAp), the main mineral constituent of dentine and tooth enamel, is commonly used as a coating component, notably for overlaying titanium– or ceramics–based implants. This thesis aims to investigate the behavior of a HAp-based coating, specifically designed to be compatible with a porous substrate. Coating layers are made by sol–gel dip coating by immersion of porous substrates made by additive manufacturing into solutions of HAp, having been mixed with polyethyleneimine (PEI), to improve the adhesion of HAp on the substrate. First, the …


Improving The Structural And Physical Yield Of Aluminum By Repeated Additions Of Iron Carbide, Fayrooz K. Albasri 2023 Presidency University, Fallujah University, Fallujah, Iraq.

Improving The Structural And Physical Yield Of Aluminum By Repeated Additions Of Iron Carbide, Fayrooz K. Albasri

Al-Bahir Journal for Engineering and Pure Sciences

Aluminum suffers from low hardness and some ductility when thermal sintering which requires reinforcement with carbide or ceramic materials as Iron FeC with volumetric properties (2,4,6,8,10 )%. For purpose of the pressing process after mixing the two powder together, a scanning electron microscope examination performed for the prepared samples and found that there is a surface and structural consistency between aluminum and iron carbide and the best homogeneity is at10 % of carbide. Also some physical tests conducted for prepared samples and the results of the real density showed that the addition of iron carbide increases the density gradually and …


The Role Of Leading-Edge Serrations In Controlling The Flow Over Owls’ Wing, Tanner Saussaman, Asif Nafi, David Charland, Hadar Ben-Gida, Roi Gurka 2023 Coastal Carolina University

The Role Of Leading-Edge Serrations In Controlling The Flow Over Owls’ Wing, Tanner Saussaman, Asif Nafi, David Charland, Hadar Ben-Gida, Roi Gurka

Physics and Engineering Science

We studied the effects of leading-edge serrations on the flow dynamics developed over an owl wing model. Owls are predatory birds. Most owl species are nocturnal, with some active during the day. The nocturnal ones feature stealth capabilities that are partially attributed to their wing microfeatures. One of these microfeatures is small rigid combs (i.e. serrations) aligned at an angle with respect to the incoming flow located at the wings' leading-edge region of the primaries. These serrations are essentially passive flow control devices that enhance some of the owls' flight characteristics, such as aeroacoustics and, potentially, aerodynamics. We performed a …


Using Powder Metallurgy Process To Produce Ceramic-Metal Composites, Ibrahim F. Abed, Salih, Y. Darweesh 2023 Physics, Department, College of Science, Cankiri Karatekin University, Cankiri, Turkey

Using Powder Metallurgy Process To Produce Ceramic-Metal Composites, Ibrahim F. Abed, Salih, Y. Darweesh

Al-Bahir Journal for Engineering and Pure Sciences

Pressing powders and engineering materials is an innovative method for producing samples with a low cost and multiple industrial applications. In the current article, copper metal was added in different volume ratios to a ceramic material, alumina, for the purpose of improving the properties of alumina, by pressing with a hydraulic press. Where the results of the article showed that the percentage of true porosity after sintering is from (26-13)% with a copper content of (5%) to (25%). As for the apparent porosity after sintering, it decreased from (26-9)% at a copper content of (5-25)%, while the water absorption was …


Ferroelectric Hafnia Surface In Action, Xia Hong 2023 University of Nebraska-Lincoln

Ferroelectric Hafnia Surface In Action, Xia Hong

Nebraska Center for Materials and Nanoscience: Faculty Publications

Piezoresponse microscopy and spectroscopy reveal the inextricable role of surface electrochemistry in stabilizing and controlling ferroelectricity in doped hafnia.

Doped hafnia (HfO2), a relatively new member of the ferroelectric family, has challenged in many ways our conventional perception of ferroelectric oxides. It possesses extremely localized electric dipoles that are independently switchable,1 making it immune to finite size effects — the loss of long-range dipole order in ferroic materials due to size scaling. While polycrystalline grains and microstructures can yield lower polarization and poorer cycling behavior in canonical ferroelectrics such as Pb(Zr,Ti)O3 and BaTiO3, in …


Design And Fabrication Of A Trapped Ion Quantum Computing Testbed, Christopher A. Caron 2023 University of Massachusetts Amherst

Design And Fabrication Of A Trapped Ion Quantum Computing Testbed, Christopher A. Caron

Masters Theses

Here we present the design, assembly and successful ion trapping of a room-temperature ion trap system with a custom designed and fabricated surface electrode ion trap, which allows for rapid prototyping of novel trap designs such that new chips can be installed and reach UHV in under 2 days. The system has demonstrated success at trapping and maintaining both single ions and cold crystals of ions. We achieve this by fabricating our own custom surface Paul traps in the UMass Amherst cleanroom facilities, which are then argon ion milled, diced, mounted and wire bonded to an interposer which is placed …


Direct Measurement Of The 114cd(��, ��)115cd Cross Section In The 1 Ev To 300 Kev Energy Range, Kofi Tutu Addo Assumin-Gyimah 2023 Mississippi State University

Direct Measurement Of The 114cd(��, ��)115cd Cross Section In The 1 Ev To 300 Kev Energy Range, Kofi Tutu Addo Assumin-Gyimah

Theses and Dissertations

The large thermal cross section of cadmium makes it ideal for many practical applications where screening of thermal neutrons is desired. For example, in non-destructive assay techniques, or for astrophysical studies of the s-process. All such applications require precise knowledge of the neutron-capture cross section on cadmium. Although there are some data on neutron-capture cross sections particularly at thermal energies and at energies relevant for astrophysics, there is very little data at most other energies. Further, the evaluated cross sections from the ENDF and JENDL databases disagree at high energies. Therefore, there is a critical need for precise knowledge of …


Study Of Microphonic Effects On The C100 Cryomodule For High Energy Electron Beam Accelerators, Caleb James Hull 2023 Old Dominion University

Study Of Microphonic Effects On The C100 Cryomodule For High Energy Electron Beam Accelerators, Caleb James Hull

Mechanical & Aerospace Engineering Theses & Dissertations

The Continuous Electron Beam Accelerator Facility (CEBAF) at Thomas Jefferson National Laboratory (JLab) is a particle accelerator which can accelerate an electron beam to relativistic speeds and apply the beam onto target samples. The C100 superconducting radio frequency (SRF) cavity is the primary accelerating structure of the C100 cryomodule, one of the many cryomodules which compose the CEBAF linear accelerator. SRF cavities are particularly sensitive to internal and external vibrations that can result in a phenomenon called microphonics which degrade the operational stability of a cryomodule.

The purpose of this thesis is to investigate the significance of mechanical disturbances on …


Experimental And Computational Aerodynamic Studies Of Axially-Oriented Low-Fineness-Ratio Cylinders, Forrest Miller 2023 Old Dominion University

Experimental And Computational Aerodynamic Studies Of Axially-Oriented Low-Fineness-Ratio Cylinders, Forrest Miller

Mechanical & Aerospace Engineering Theses & Dissertations

For the successful completion of atmospheric entry, descent, and landing (EDL) missions, a body geometry must be selected which provides favorable dynamic aerodynamic properties. The types of experimental facilities capable of collecting information on these properties are limited; however, their numbers are growing thanks to the continued work by the aerodynamics community. NASA Langley Research Center (LaRC) is conducting dynamic aerodynamic testing using a subsonic magnetic suspension and balance system (MSBS), with the end goal of implementing a supersonic MSBS facility at NASA Glenn Research Center. MSBSs are also currently used at the Institute of Fluid Science (IFS) at Tohoku …


Finite Element Analysis Of A Coconut (Cocos Nucifera L.) Climbing Mechanism, Arjay O. Afan, Omar F. Zubia, Adrian A. Borja, Ralph Kristoffer B. Gallegos 2023 Institute of Agricultural and Biosystems Engineering, College of Engineering and Agro-Industrial Technology, University of the Philippines Los Baños, College, Laguna, 4031 Philippines

Finite Element Analysis Of A Coconut (Cocos Nucifera L.) Climbing Mechanism, Arjay O. Afan, Omar F. Zubia, Adrian A. Borja, Ralph Kristoffer B. Gallegos

The Philippine Agricultural Scientist

A coconut climber mechanism was subjected to Finite Element Analysis (FEA) to improve its overall design and analyze its strength characteristics. The von Mises stress, total deformation, and factor of safety were evaluated using static structural analysis for the seat and pedal assemblies of the mechanism. The design has a minimum yielding factor of safety of 7.03 for the seat assembly and 12.09 for the pedal assembly. If aluminum is used as an alternative to steel, the prototype's weight can be reduced to at least 64.56% without compromising its strength properties. The weight reduction by using aluminum is expected to …


Tardys Quantifiers: Extracting Temporal And Reversible Dynamical Symmetries, Nhat Vu Minh Nguyen, Arjendu K. Pattanayak, Andres Aragoneses 2023 Eastern Washington University

Tardys Quantifiers: Extracting Temporal And Reversible Dynamical Symmetries, Nhat Vu Minh Nguyen, Arjendu K. Pattanayak, Andres Aragoneses

2023 Symposium

One of the great challenges in complex and chaotic dynamics is to reveal the details of its underlying determinism. This can be manifest in the form of temporal correlations or structured patterns in the dynamics of a measurable variable. These temporal dynamical structures are sometimes a consequence of hidden global symmetries. Here we identify the temporal (approximate) symmetries of a semiconductor laser with external optical feedback, based on which we define the Temporal And Reversible DYnamical Symmetry (TARDYS) quantifiers to evaluate the relevance of specific temporal correlations in a time series. We show that these symmetries are also present in …


Effective Nanomembranes From Chitosan/Pva Blend Decorated Graphene Oxide With Gum Rosin And Silver Nanoparticles For Removal Of Heavy Metals And Microbes From Water Resources, Mohamed Morsy 2023 The British University in Egypt

Effective Nanomembranes From Chitosan/Pva Blend Decorated Graphene Oxide With Gum Rosin And Silver Nanoparticles For Removal Of Heavy Metals And Microbes From Water Resources, Mohamed Morsy

Nanotechnology Research Centre

No abstract provided.


Method Of Evanescently Coupling Whispering Gallery Mode Optical Resonators Using Liquids [U.S. Patent Us11650370b2], Hengky Chandrahalim, Kyle T. Bodily 2023 Air Force Institute of Technology

Method Of Evanescently Coupling Whispering Gallery Mode Optical Resonators Using Liquids [U.S. Patent Us11650370b2], Hengky Chandrahalim, Kyle T. Bodily

Faculty Publications

The present invention relates to evanescently coupling whispering gallery mode optical resonators having a liquid coupling as well as methods of making and using same. The aforementioned evanescently coupling whispering gallery mode optical resonators having a liquid couplings provide increased tunability and sensing selectivity over current same. The aforementioned. Applicants’ method of making evanescent-wave coupled optical resonators can be achieved while having coupling gap dimensions that can be fabricated using standard photolithography. Thus economic, rapid, and mass production of coupled WGM resonators-based lasers, sensors, and signal processors for a broad range of applications can be realized.


Domain Wall Saddle Point Morphology In Ferroelectric Triglycine Sulfate, C. J. McCluskey, A. Kumar, Alexei Gruverman, I. Luk’yanchuk, J. M. Gregg 2023 Queen’s University Belfast

Domain Wall Saddle Point Morphology In Ferroelectric Triglycine Sulfate, C. J. Mccluskey, A. Kumar, Alexei Gruverman, I. Luk’Yanchuk, J. M. Gregg

Alexei Gruverman Publications

Ferroelectric domain walls, across which there is a divergence in polarization, usually have enhanced electrical conductivity relative to bulk. However, in lead germanate, head-to-head and tail-to-tail walls are electrically insulating. Recent studies have shown that this is because, when oppositely oriented domains meet, polar divergence is obviated by a combination of domain bifurcation and suspected local dipolar rotation. To explore the uniqueness, or otherwise, of this microstructure, we have used tomographic piezoresponse force microscopy to map three-dimensional domain morphologies in another uniaxial ferroelectric system: triglycine sulfate. This mapping reveals an abundance of domain wall saddle points, which are characteristic of …


Effect On Focusing Fields By Ferromagnetic Cell Cores In Linear Induction Accelerators, Cooper Guillaume 2023 Liberty University

Effect On Focusing Fields By Ferromagnetic Cell Cores In Linear Induction Accelerators, Cooper Guillaume

Senior Honors Theses

In the Los Alamos National Laboratories DARHT facility, there are two perpendicular linear induction accelerators, LIAs. The LIAs’ solenoids produce magnetic fields which focus the electron beam. Simultaneously, the accelerating pulse creates a magnetic field. These two field intensities act upon a ferromagnetic material in the cells to enhance magnetic flux density. Due to the nonlinearity of the material, this flux density will reach a saturation point. In turn, the magnetic field intensity of the axial solenoidal magnetic field will be affected and slightly altered. The width of the electron beam will increase, causing a decrease in effectiveness. Through simulation, …


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