Engineering Physics Commons^™

Surface Termination And Schottky-Barrier Formation Of In4Se3(001), Archit Dhingra, Pavlo V. Galiy, Lu Wang, Nataliia S. Vorobeva, Alexey Lipatov, Angel Torres, Taras M. Nenchuk, Simeon J. Gilbert, Alexander Sinitskii, Andrew J. Yost, Wai-Ning Mei, Keisuke Fukutani, Jia Shiang Chen, Peter Dowben

Peter Dowben Publications

The surface termination of In₄Se₃(001) and the interface of this layered trichalcogenide, with Au, was examined using x-ray photoemission spectroscopy. Low energy electron diffraction indicates that the surface is highly crystalline, but suggests an absence of C2v mirror plane symmetry. The surface termination of the In₄Se₃(001 is found, by angle-resolved x-ray photoemission spectroscopy, to be In, which is consistent with the observed Schottky barrier formation found with this n-type semiconductor. Transistor measurements confirm earlier results from photoemission, suggesting that In₄Se₃(001 is an n-type semiconductor, so that Schottky barrier …

Corrosion Prevention, Matthew Walker

Physics

In Insulated Solar Electric Cooking (ISEC), heating is done by passing current through a chain of diodes directly connected to a solar panel (Gius et al, 2019). It is crucially important that the wires remain conducting, but not conduct to any metal surface that might short the heating circuit. Corrosion of any wires will cause a loosening of the mechanical (twisted) wire connection and could result in a loss of electrical connection completely, or undesired increased resistance.

Mechani-Kits Senior Design Project, Jake Utley, Sophie Carson, Vincent Seguin

Mechanical Engineering

Studies suggest that when designed and executed well, hands-on activities can enhance student understanding of key mechanics concepts. Current products are expensive and typically not designed to meet a variety of learning objectives. Through the Mechanics of Inclusion and Inclusivity in Mechanics grant, the Cal Poly Physics and Engineering Departments are seeking to incorporate new hands-on activities into their courses. Our team has designed three inexpensive ”MechaniKits” to be used in physics, statics and dynamics courses [1]. This Final Design Review outlines our findings, objectives, and final designs for this project. It also explains our manufacturing and design verification plans. …

Towards Realism Interpretation Of Wave Mechanics Based On Maxwell Equations In Quaternion Space And Some Implications, Including Smarandache’S Hypothesis, Florentin Smarandache, Victor Christianto, Yunita Umniyati

Branch Mathematics and Statistics Faculty and Staff Publications

No abstract provided.

A Physics-Based Machine Learning Study Of The Behavior Of Interstitial Helium In Single Crystal W–Mo Binary Alloys, Adib J. Samin

Faculty Publications

In this work, the behavior of dilute interstitial helium in W–Mo binary alloys was explored through the application of a first principles-informed neural network (NN) in order to study the early stages of helium-induced damage and inform the design of next generation materials for fusion reactors. The neural network (NN) was trained using a database of 120 density functional theory (DFT) calculations on the alloy. The DFT database of computed solution energies showed a linear dependence on the composition of the first nearest neighbor metallic shell. This NN was then employed in a kinetic Monte Carlo simulation, which took into …

The Parity-Violating Asymmetry In The N→Δ Transition At Low Q2, Thamraa A. Alshayeb

Doctoral Dissertations

Qweak has used the parity violating asymmetry to test the Standard Model (SM) by constantly flipping helicity states of a longitudinally polarized electron beam that scatters in the unpolarized LH2 target. The main focus of the Qweak experiment at Jefferson Lab was the recently published determination of the proton’s weak charge. In order to make corrections to the measured asymmetry at low 𝑄 2 due to inelastically scattered electrons, dedicated measurements were made of the parity violating asymmetry in the N→∆ transition at two different beam energies.

The measured inelastic asymmetries are used to extract the low energy constant dΔ, …

An Investigation Of Diode Failure, Nicholas James Adams

Physics

Solar electricity can be used to cheaply cook food and charge electronic devices. We investigate the viability of using diodes as heating elements for insulated solar electric cooking (ISEC). In addition, information on designing and constructing ISEC compatible phone chargers and rechargeable LED lighting systems is included.

Investigation Of Mnxni1-Xo Thin Films Using Pulsed Laser Deposition, Md Ashif Anwar

Graduate Theses/Dissertations

The exchange bias (EB) effect, especially in nanomaterials, is highly promising for use in antiferromagnet-based spintronics applications. NiO is a well known antiferromagnetic material with a high Néel temperature (525K) and can exhibit ferromagnetism/ ferrimagnetism by adding other magnetic transition elements. Our previous work has shown that the antiferromagnetic characteristics of conventional NiO insulating nanostructured material can be altered to have substantial ferrimagnetic characteristics by doping NiO with Mn or Co. Pulsed laser deposition (PLD) was used to grow heterostructures comprised of a nanostructured thin NiO film deposited on the surface of a MgO (100) and Al₂O_{3 …}

285— Modifications Of Cosmic Watch Muon Detectors For Deployment At Letchworth State Park, Kevin Seitz

GREAT Day Posters

For an American Physical Society funded physics outreach project, fifteen Cosmic Watch cosmic ray muon detectors, designed at MIT, are being assembled by students at Geneseo. Over the summer of 2020, ten detectors will be deployed around Letchworth State Park to educate park visitors about cosmic rays. The muon detection rate and cumulative count are displayed on a small OLED screen, with an LED flashing every time a muon passes through the detector’s scintillator. Each incidence is also logged to a micro SD card. Customized open-source software was used to allow the OLED and SD card to work simultaneously. The …

Questaal: A Package Of Electronic Structure Methods Based On The Linear Muffin-Tin Orbital Technique, Dimitar Pashov, Swagata Acharya, Walter R.L. Lambrecht, Jerome Jackson, Kirill Belashchenko, Athanasios Chantis, Francois Jamet, Mark Van Schilfgaarde

Kirill Belashchenko Publications

This paper summarises the theory and functionality behind Questaal, an open-source suite of codes for calculating the electronic structure and related properties of materials from first principles. The formalism of the linearised muffin-tin orbital (LMTO) method is revisited in detail and developed further by the introduction of short-ranged tight-binding basis functions for full-potential calculations. The LMTO method is presented in both Green's function and wave function formulations for bulk and layered systems. The suite's full-potential LMTO code uses a sophisticated basis and augmentation method that allows an efficient and precise solution to the band problem at different levels of theory, …

Syllabus Ee330 Electromagnetics, Nicholas Madamopoulos

Open Educational Resources

Concepts covered in the undergraduate electrical engineering class of electromagnetics

The Emergence Of The Local Moment Molecular Spin Transistor, Guanhua Hao, Ruihua Cheng, Peter Dowben

Peter Dowben Publications

Local moment molecular systems have now been used as the conduction channel in gated spintronics devices, and some of these three terminal devices might even be considered molecular spin transistors. In these systems, the gate voltage can be used to tune the molecular level alignment, while applied magnetic fields have an influence on the spin state, altering the magnetic properties, and providing insights to the magnetic anisotropy. More recently, the use of molecular spin crossover complexes, as the conduction channel, has led to devices that are both nonvolatile and have functionality at higher temperatures. Indeed, some devices have now been …

Probing Ferroelectricity By X-Ray Absorption Spectroscopy In Molecular Crystals, Fujie Tang, Xuanyuan Jiang, Hsin Yu Ko, Jianhang Xu, Mehmet Topsakal, Guanhua Hao, Alpha T. N'Diaye, Peter Dowben, Deyu Lu, Xiaoshan Xu, Xifan Wu

Peter Dowben Publications

We carry out X-ray absorption spectroscopy experiment at the oxygen K edge in croconic acid (C₅H₂O₅) crystal as a prototype of ferroelectric organic molecular solid, whose electric polarization is generated by proton transfer. The experimental spectrum is well reproduced by the electron-hole excitation theory simulations from configuration generated by ab initio molecular dynamics simulation. When inversion symmetry is broken in the ferroelectric state, the hydrogen bonding environment on the two bonded molecules become inequivalent. Such a difference is sensitively probed by the bound excitation in the pre-edge, which is strongly localized on the excited …

Optimizing Llrf Parameters In The Electron-Ion Collider, William M. Bjorndahl

Physics

To improve particle interaction in the future Electron-Ion Collider (EIC), we investigated different feedback implementations to control the accelerating voltage and examined the power and beam phase for each instance. Using MATLAB, we studied three feedback mechanisms: Direct, One Turn, and Feedforward. Enacting feedforward yielded the best performance. To minimize the klystron power consumption, we analyzed different Low-Level Radio Frequency (LLRF) parameters such as detuning. Combining theory and simulated results, we found the optimal detuning value that minimizes klystron power consumption.

Enhanced Brdf Modeling Using Directional Volume Scatter Terms, Michael W. Bishop

Theses and Dissertations

Accurate Bidirectional Reflectance Distribution Function (BRDF) models provide critical scatter behavior for computer graphics and remote sensing performance. The popular microfacet class of BRDF models is geometric-based and computationally inexpensive compared to wave-optics models. Microfacet models commonly account for surface scatter and Lambertian volume scatter, but not directional volume scatter. This work proposes directional volume scatter modeling for enhanced performance over all observation regions. Five directional volume models are incorporated into the modified Cook-Torrance microfacet model. Additionally, a semi-empirical directional volume term is presented based on the Beckmann microfacet distribution and a modified Fresnel reflection term. High fidelity, low density …

Effects Of Intrinsic Defects And Alloying With Fe On The Half-Metallicity Of Co2Mnsi, G. G. Baez Flores, Ivan A. Zhuravlev, Kirill Belashchenko

Kirill Belashchenko Publications

The electronic structure and half-metallic gap of Co2MnSi in the presence of crystallographic defects, partial Fe substitution for Mn, and thermal spin fluctuations are studied using the coherent potential approximation and the disordered local moment method. In the presence of 5% Co or Mn vacancies the Fermi level shifts down to the minority-spin valence-band maximum. In contrast to NiMnSb, both types of Mn antisite defects in Co2MnSi are strongly exchange coupled to the host magnetization, and thermal spin fluctuations do not strongly affect the half-metallic gap. Partial substitution of Mn by Fe results in considerable changes in the Bloch spectral …

Pair-A-Dice Lost: Experiments In Dice Control, Robert H. Scott Iii, Donald R. Smith

UNLV Gaming Research & Review Journal

This paper presents our findings from experiments designed to test whether we could use a custom-made dice throwing machine applying common dice control methods to produce dice rolls that differ from random. In earlier research we calculated the percentages of control a craps player needs to break even or beat the house (Smith and Scott, 2018). Using the most common practices of dice control in craps, we established how dice should be configured (i.e., set) and thrown to achieve certain outcomes such as not rolling a seven in the point cycle. We decided to run experiments to see if a …

Dual-Axis Solar Tracker, Bryan Kennedy

All Undergraduate Projects

Renewable energies, and fuels that are not fossil fuel-based, are one of the prolific topics of debate in modern society. With climate change now becoming a primary focus for scientists and innovators of today, one of the areas for the largest amount of potential and growth is that of the capturing and utilization of Solar Energy. This method involves using a mechanical system to track the progression of the sun as it traverses the sky throughout the day. A dual-axis solar tracker such as the one designed and built for this project, can follow the sun both azimuthally and in …

Diffusion Doping Of Cobalt In Rod-Shape Anatase Tio2 Nanocrystals Leads To Antiferromagnetism†, Shahzahan Mia, Shelton J.P. Varapragasam, Aravind Baride, Choumini Balasanthiran, Balamurugan Balasubramanian, Robert M. Rioux, James D. Hoefelmeyer

Nebraska Center for Materials and Nanoscience: Faculty Publications

Cobalt(II) ions were adsorbed to the surface of rod-shape anatase TiO2 nanocrystals and subsequently heated to promote ion diffusion into the nanocrystal. After removal of any remaining surface bound cobalt, a sample consisting of strictly cobalt-doped TiO2 was obtained and characterized with powder Xray diffraction, transmission electron microscopy, UV-visible spectroscopy, fluorescence spectroscopy, X-ray photoelectron spectroscopy, SQUID magnetometry, and inductively-coupled plasma atomic emission spectroscopy. The nanocrystal morphology was unchanged in the process and no new crystal phases were detected. The concentration of cobalt in the doped samples linearly correlates with the initial loading of cobalt(II) ions on the nanocrystal surface. Thin …

Detection Of Decoupled Surface And Bulk States In Epitaxial Orthorhombic Sriro3 Thin Films, Prescott E. Evans, Takashi Komesu, Le Zhang, Ding-Fu Shao, Andrew J. Yost, Shiv Kumar, Eike F. Schwier, Kenya Shimada, Evgeny Y. Tsymbal, Xia Hong, P. A. Dowben

Peter Dowben Publications

We report the experimental evidence of evolving lattice distortion in high quality epitaxial orthorhombic SrIrO3(001) thin films fully strained on (001) SrTiO3 substrates. Angle-resolved X-ray photoemission spectroscopy studies show that the surface layer of 5 nm SrIrO3 films is Sr–O terminated, and subsequent layers recover the semimetallic state, with the band structure consistent with an orthorhombic SrIrO3(001) having the lattice constant of the substrate. While there is no band folding in the experimental band structure, additional super-periodicity is evident in low energy electron diffraction measurements, suggesting the emergence of a transition layer with crystal symmetry evolving from the SrTiO3 substrate …

Manipulation Of The Molecular Spin Crossover Transition Of Fe(H2b(Pz)2)2(Bipy) By Addition Of Polar Molecules, Paulo S. Costa, Guanhua Hao, Alpha T. N'Diaye, Lucie Routaboul, Pierre Braunstein, Xin Zhang, Jian Zhang, Thilini K. Ekanayaka, Qin Yin Shi, V. L. Schlegel, Bernard Doudin, Axel Enders, Peter Dowben

Peter Dowben Publications

The addition of various dipolar molecules is shown to affect the temperature dependence of the spin state occupancy of the much studied spin crossover Fe(II) complex, [Fe{H2B(pz)2}2(bipy)] (pz = pyrazol-1-yl, bipy = 2,2′-bipyridine). Specifically, the addition of benzimidazole results in a re-entrant spin crossover transition, i.e. the spin state starts in the mostly low spin state, then high spin state occupancy increases, and finally the high spin state occupancy decreases with increasing temperature. This behavior contrasts with that observed when the highly polar p -benzoquinonemonoimine zwitterion C6H2(..NH2)2(..O)2 was mixed with [Fe{H2B(pz)2}2(bipy)], which resulted in locking [Fe{H2B(pz)2}2(bipy)] largely into a low …

Investigating New Methods To Develop Perovskite Solar Cells, Amani Hussain Alfaifi

Electronic Theses and Dissertations

Discovering the potential of organic-inorganic metal halide perovskites (MHP) as a harvesting material in solar cells has strongly affected the research direction in solar energy. The fascinating optical and electronic properties offered by MHP combined with tremendous effort from scientists around the world have improved the efficiency to about 25% in a decade.

In the first part of the dissertation, we studied the lamination process as a new fabrication method for producing self-encapsulated perovskite solar cells based on laminating half stacks,as opposed to the conventional layer-by-layer method. Our work focused on optimizing the lamination process of complex triple cations perovskite …

Chiral Magnetism And High-Temperature Skyrmions In B20-Ordered Co-Si, Balamurugan Balasubramanian, Priyanka Manchanda, Rabindra Pahari, Zhen Chen, Wenyong Zhang, Shah R. Valloppilly, Xingzhong Li, Anandakumar Sarella, Lanping Yue, Ahsan Ullah, Pratibha Dev, David A. Muller, Ralph Skomski, George C. Hadjipanayis, David J. Sellmyer

Nebraska Center for Materials and Nanoscience: Faculty Publications

Magnets with chiral crystal structures and helical spin structures have recently attracted much attention as potential spin-electronics materials, but their relatively low magnetic-ordering temperatures are a disadvantage. While cobalt has long been recognized as an element that promotes high-temperature magnetic ordering, most Co-rich alloys are achiral and exhibit collinear rather than helimagnetic order. Crystallographically, the B20-ordered compound CoSi is an exception due to its chiral structure, but it does not exhibit any kind of magnetic order. Here, we use nonequilibrium processing to produce B20-ordered Co_1+xSi_1−x with a maximum Co solubility of x = 0.043. Above a critical …

Rod-Shape Theranostic Nanoparticles Facilitate Antiretroviral Drug Biodistribution And Activity In Human Immunodeficiency Virus Susceptible Cells And Tissues, Bhavesh D. Kevadiya, Brendan Ottemann, Insiya Z. Mukadam, Laura Castellanos, Kristen Sikora, James R. Hilaire, Jatin Machhi, Jonathan Herskovitz, Dhruvkumar Soni, Mahmudul Hasan, Wenting Zhang, Anandakumar Sarella, Jered Garrison, Joellyn Mcmillan, Benson Edagwa, R. Lee Mosley, Richard W. Vachet, Howard E. Gendelman

Nebraska Center for Materials and Nanoscience: Faculty Publications

Human immunodeficiency virus theranostics facilitates the development of long acting (LA) antiretroviral drugs (ARVs) by defining drug-particle cell depots. Optimal drug formulations are made possible based on precise particle composition, structure, shape and size. Through the creation of rod-shaped particles of defined sizes reflective of native LA drugs, theranostic probes can be deployed to measure particle-cell and tissue biodistribution, antiretroviral activities and drug retention.

Methods: Herein, we created multimodal rilpivirine (RPV) ¹⁷⁷lutetium labeled bismuth sulfide nanorods (¹⁷⁷LuBSNRs) then evaluated their structure, morphology, configuration, chemical composition, biological responses and adverse reactions. Particle biodistribution was analyzed by single …

Svat4: A Computer Program For Visualization And Analysis Of Crystal Structures, Xingzhong Li

Nebraska Center for Materials and Nanoscience: Faculty Publications

SVAT4 is a computer program for interactive visualization of three-dimensional crystal structures, including chemical bonds and magnetic moments. A wide range of functions, e.g. revealing atomic layers and polyhedral clusters, are available for further structural analysis. Atomic sizes, colors, appearance, view directions and view modes (orthographic or perspective views) are adjustable. Customized work for the visualization and analysis can be saved and then reloaded. SVAT4 provides a template to simplify the process of preparation of a new data file. SVAT4 can generate high-quality images for publication and animations for presentations. The usability of SVAT4 is broadened by a software suite …

A Review On Superluminal Physics And Superluminal Communication In Light Of The Neutrosophic Logic Perspective, Victor Christianto, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In a recent paper, we describe a model of quantum communication based on combining consciousness experiment and entanglement, which can serve as impetus to stop 5G-network-caused diseases. Therefore, in this paper we consider superluminal physics and superluminal communication as a bridge or intermediate way between subluminal physics and action-at-a-distance (AAAD) physics, especially from neutrosophic logic perspective. Although several ways have been proposed to bring such a superluminal communication into reality, such as Telluric wave or Telepathy analog of Horejev and Baburin, here we also review two possibilities: quaternion communication and also quantum communication based on quantum noise. Further research is …

A Short Remark On Vortex As Fluid Particle From Neutrosophic Logic Perspective, Victor Christianto, Florentin Smarandache

Branch Mathematics and Statistics Faculty and Staff Publications

In a previous paper in this journal (IJNS), it is mentioned about a possible approach to re-describe QED without renormalization route. As it is known that in literature, there are some attempts to reconcile vortex-based fluid dynamics and particle dynamics. Some attempts are not quite as fruitful as others. As a follow up to previous paper, the present paper will discuss two theorems for developing unification theories, and then point out some new proposals including by Simula (2020) on how to derive Maxwell equations in superfluid dynamics setting; this could be a new alternative approach towards “fluidicle” or “vorticle” model …

Quantitative Study Of The Energy Changes In Voltage-Controlled Spin Crossover Molecular Thin Films, Aaron Mosey, Ashley S. Dale, Guanhua Hao, Alpha T. N’Diaye, Peter Dowben, Ruihua Cheng

Peter Dowben Publications

Voltage-controlled nonvolatile isothermal spin state switching of a [Fe{H2B(pz)₂}₂(bipy)] (pz=tris(pyrazol-1-1y)-borohydride, bipy=2,2’-bipyridine) film, more than 40 to 50 molecular layers thick, is possible when it is adsorbed onto a molecular ferroelectric substrate. Accompanying this high spin and low spin state switching, at room temperature, we observe a remarkable change in conductance, thereby allowing not only non-volatile voltage control of the spin state (“write”), but also current sensing of the molecular spin state (“read”). Monte Carlo Ising model simulations of the high spin state occupancy, extracted from x-ray absorption spectroscopy, indicate that the energy difference between the low …

Ferroelectric Domain Wall Memristor, James P. V. Mcconville, Haidong Lu, Bo Wang, Yueze Tan, Charlotte Cochard, Michele Conroy, Kalani Moore, Alan Harvey, Ursel Bangert, Long-Qing Chen, Alexei Gruverman, J. M. Gregg

Alexei Gruverman Publications

A domain wall-enabled memristor is created, in thin film lithium niobate capacitors, which shows up to twelve orders of magnitude variation in resistance. Such dramatic changes are caused by the injection of strongly inclined conducting ferroelectric domain walls, which provide conduits for current flow between electrodes. Varying the magnitude of the applied electric-field pulse, used to induce switching, alters the extent to which polarization reversal occurs; this systematically changes the density of the injected conducting domain walls in the ferroelectric layer and hence the resistivity of the capacitor structure as a whole. Hundreds of distinct conductance states can be produced, …

Synthesis And Characterization Of Hybrid Organic Coating System To Reduce Thermal Degradation Of Solar Cells, Mohd Zaini Farah Khaleda

Student Works (2020-2029)

Thermal-decreasing hybrid organic coatings were developed for crystalline solar cells by using two types of binder systems; namely Aminopropyltriethoxysolution (APTES) / Methyltrimethoxysilane (MTMS) binder system (labelled as B1) and Methyltrimethoxysilane (MTMS) / nitric acid (HNO3) binder system (labelled as B2). Three types of nanoparticles; Titanium dioxide, TiO2 (Anatase), Zinc oxide, ZnO and Tin dioxide, SnO2 nanoparticles with different weight percentage were introduced inside each binder system namely; 20 wt%, TiO2 (T1B1 coating), 60 wt% TiO2 (T2B1 coating), 20 wt% ZnO (Z1B1 coating), 60 wt% ZnO (T2B1 coating), 20 wt% SnO2 (S1B1 coating) and 60 wt% SnO2 (S2B1 coating) for B1 …