Other Physics Commons^™

Helmholtz Spacing Of Thin Rectangular Magnetic Field Coils, Karl J. Ahrendsen, Sarah Reyes, Timothy J. Gay

Timothy J. Gay Publications

In this Note, we discuss the Helmholtz spacing for a pair of thin rectangular coils of arbitrary aspect ratio and consider how best to use such coils to compensate for Earth’s magnetic field along the coils’ Cartesian symmetry axes. Such coils are frequently used in conjunction with charged-particle beam machines. The Helmholtz spacing varies non-monotonically between that for square coils and that for four optimally spaced infinite wires. We consider other coil spacings that extend the length over which the field varies by less than some tolerance along the Cartesian symmetry axes. The calculations also provide a convenient means to …

Possible Superconductivity Above 40 K In Rhenium-Doped Strontium Ruthenates Indicated By Fourier-Transform Infrared Spectroscopy, Yurii Aleschenko, Boris Gorshunov, Elena Zhukova, Andrey Muratov, Alexander Dudka, Rajendra Dulal, Serafim Teknowijoyo, Sara Chahid, Vahan Nikoghosyan, Armen Gulian

Mathematics, Physics, and Computer Science Faculty Articles and Research

Strontium ruthenates have a lot of similarities with copper oxide superconductors and are a very interesting object for investigation of mechanisms and conditions which lead to high-temperature superconductivity. We report here on multiple experimental indications of superconductivity with the onset above 40K in strontium ruthenate doped by rhenium and selenium with chlorine used as a flux. The main experimental evidence comes from FTIR spectroscopy of this material followed by the ac and dc magnetization, as well as its heat capacity and magnetoresistance. Structural and morphological studies reveal the heterophase nature of this polycrystalline material as well as changes of lattice …

Laboratory Experiments To Study The Effect Of Temperature On Cigs Solar Cells, Asliddin Komilov

Acta of Turin Polytechnic University in Tashkent

Abstract - In this work, we studied the effect of temperature on CIGS solar cells as a function of the thickness of the CdS buffer layer. It was found that with an increase in temperature in CIGS-based solar cells (SC), an increase in the acceptor doping concentration occurs in the region where carrier-generation- recombination prevails. It was also established that in solar cells with a thin buffer layer, generationrecombination through interface prevail, and the temperature influences them more.

Indium Segregation To The Selvedge Of In4Se3 (001), Archit Dhingra, Zoe G. Marzouk, Esha Mishra, Pavlo V. Galiy, Taras M. Nenchuk, Peter Dowben

Peter Dowben Publications

Thermal motion of the surface atoms will lead to a decrease in photoemission intensity, while surface segregation may result in an increase of some phostoemission intensities. For In4Se3(001), both effects are seen. The Debye–Waller factor plot, based on the temperature dependent X-ray photoemission spectroscopy (XPS) measurements on In4Se3(001), suggests an upper bound of 203 ± 6 K for the effective Debye temperature, based on the surface component of the In 3d5/2 core-level. Indium is found to segregate to selvedge (subsurface region) of the crystal.

Efficient Time-Stepping Approaches For The Dispersive Shallow Water Equations, Linwan Feng

Dissertations

This dissertation focuses on developing efficient and stable (high order) time-stepping strategies for the dispersive shallow water equations (DSWE) with variable bathymetry. The DSWE extends the regular shallow water equations to include dispersive effects. Dispersion is physically important and can maintain the shape of a wave that would otherwise form a shock in the shallow water system.

In some cases, the DSWE may be simplified when the bathymetry length scales are small (or large) in relation to other length scales in the shallow water system. These simplified DSWE models, which are related to the full DSWEs, are also considered in …

Flare Emission Observed In High Resolution And Comparison With Numerical Modeling, Nengyi Huang

Dissertations

As one of the most intense activities on the solar surface, flares have been extensively observed and studied ever since the first report. The standard model of solar flares has been established and commonly accepted. However, many limitations from the researching tools have left some of the problems unsolved or controversial. For example, the density of electrons in the corona is lower than it is required to activate the observed emission in HXR, and the mechanism that these electron beams can penetrate down to lower chromosphere is unclear. Many theoretical scenarios were suggested, and more observations had been in need. …

Modeling Anatomic Changes For Adaptive Radiotherapy In Locally Advanced Lung Cancer Patient Population, James Alexander Kavanaugh

LSU Doctoral Dissertations

Anatomic changes occurring mid-treatment for patients undergoing radiation therapy for locally advanced lung cancer can degrade the quality of the intended treatment plan. These changes include tumor regression, geometric misalignment, and lung density changes (atelectasis and pleural effusion), and are visible on the daily 3D cone beam CT (CBCT). To maintain the intended treatment quality, adaptive radiotherapy (ART) can be employed to modify the treatment plan to account for these anatomic changes. However, the evaluation on when to adapt is currently completed manually by the treating clinicians, resulting in a subjective and inconsistent application. To address these limitations, a series …

Artificial Neural Network Discovery Of A Switchable Metasurface Reflector, J. R. Thompson, J. A. Burrow, P. J. Shah, J. Slagle, E. S. Harper, A. Van Rynbach, I. Agha, M. S. Mills

Electro-Optics and Photonics Faculty Publications

Optical materials engineered to dynamically and selectively manipulate electromag- netic waves are essential to the future of modern optical systems. In this paper, we simulate various metasurface configurations consisting of periodic 1D bars or 2D pillars made of the ternary phase change material Ge2Sb2Te5 (GST). Dynamic switching behavior in reflectance is exploited due to a drastic refractive index change between the crystalline and amorphous states of GST. Selectivity in the reflection and transmission spectra is manipulated by tailoring the geometrical parameters of the metasurface. Due to the immense number of possible metasurface configurations, we train deep neural networks capable of …

Elmer Fem-Dakota: A Unified Open-Source Computational Framework For Electromagnetics And Data Analytics, Anjali Sandip

Mechanical Engineering Faculty Publications

Open-source electromagnetic design software, Elmer FEM, was interfaced with data analytics toolkit, Dakota. Furthermore, the coupled software was validated against a benchmark test. The interface developed provides a unified open-source computational framework for electromagnetics and data analytics. Its key features include uncertainty quantification, surrogate modelling and parameter studies. This framework enables a richer understanding of model predictions to better design electric machines in a time sensitive manner.

An Expanded Model Of Unmatter From Neutrosophic Logic Perspective: Towards Matter-Spirit Unity View, Florentin Smarandache, Victor Christianto, Robert Neil Boyd

Branch Mathematics and Statistics Faculty and Staff Publications

In Neutrosophic Logic, a basic assertion is that there are variations of about everything that we can measure; the variations surround three parameters called T, I, F (truth, indeterminacy, falsehood) which can take a range of values. A previous paper in IJNS, 2020 shortly reviews the links among aether and matter creation from the perspective of Neutrosophic Logic. In any case, matter creation process in nature stays a major puzzle for physicists, scientists and other science analysts. To this issue neutrosophic logic offers an answer: "unmatter." This paper examines an extended model of unmatter, to incorporate issue soul solidarity. So, …

Synthesis And Characterization Of Carbon Coated Barium Titanate Core-Shell Nanoparticles, Moudip Nandi

Graduate Theses/Dissertations

Core-shell nanoparticles (CSNP) with fascinating ferroelectric properties have diverse applications in biotechnology and the electronic field of studies. Among so many perovskites, barium titanate (BTO) nanoparticles draw much interest due to their distinct electronic and ferroelectric features. Additionally, the incorporation of carbon in the shell of CSNP makes it suitable for application in many fields due to its innocuous nature. Carbon not only increases the biocompatible properties of an element but also gives mechanical stability to the CSNP. This thesis is targeted towards the synthesis of oxide-carbide CSNP, where the core is made of BTO and the shell is made …

Electrochemically-Modulated Surface Plasmon Waves At A Nano-Scale For Investigations And Applications Of Redox Assemblies., Aymen Hasan Qatamin

Electronic Theses and Dissertations

In this thesis, an electrochemically-modulated surface plasmon resonance (EC-SPR) technique was developed for challenging investigations and applications in different redox assemblies. The principle of the technique is based on the nano-scale confined and sensitive interplay between a surface plasmon wave and a redox-active probe featuring an optical transition when undergoing a faradaic redox process. Such faradaic process is electrochemically controlled by modulating the surface electric potential of the SPR platform to create an optical output signal that is substantially immune to the negative impacts of background environment and enabling the identification and quantification minute properties linked to a molecular event …

Active Magnetic Radiation Shielding For Long-Duration Human Spaceflight, Kristine Ferrone

Dissertations and Theses (Open Access)

Exploration of interplanetary space presents dramatic hazards to human survival.

Space radiation hazards outside the protection of the Earth’s magnetosphere can

produce both acute and chronic health risks and thus become limiting factors for

NASA’s planned mission to Mars by the 2030s. Radiation exposure on a Mars mission

is delivered primarily by high energy ions from galactic cosmic rays and moderate

energy protons from solar particle events. The chronic radiation dose due to galactic

cosmic rays on a typical Mars mission is on the order of 1 Sv, and additional acute

radiation dose from solar flares can reach over 4 …

Design, Monitoring And Management Approaches For The Root-Zone In Microgravity, Scott B. Jones

Funded Research Records

No abstract provided.

Site Selective Adsorption Of The Spin Crossover Complex Fe(Phen)2(Ncs)2 On Au(111), Sumit Beniwal, Suchetana Sarkar, Felix Baier, Birgit Weber, Peter Dowben, Axel Enders

Peter Dowben Publications

The iron(II) spin crossover complex Fe(1,10-phenanthroline)₂(NCS)₂, dubbed Fe-phen, has been studied with scanning tunneling microscopy, after adsorption on the 'herringbone' reconstructed surface of Au(111) for sub-monolayer coverages. The Fe-phen molecules attach, through their NCS-groups, to the Au atoms of the fcc domains of the reconstructed surface only, thereby lifting the herringbone reconstruction. The molecules stack to form 1D chains, which run along the Au[110] directions. Neighboring Fe-phen molecules are separated by approximately 2.65 nm, corresponding to 9 atomic spacings in this direction. The molecular axis, defined by the two phenanthroline groups, is aligned perpendicular to the …

The Crisis Of Communication In The Information Age: Revisiting C.P. Snow's Two Cultures In The Era Of Fake News, Aaron Green

Irish Communication Review

The purpose of this paper is to revisit C.P. Snow’s “Two Cultures” lecture in light of the cultural dominance of information technology. The crisis of communication in the information age, whether in fake news, political polarisation or science denial, has come about because both scientific and literary cultures, in seeking a world without entropy, have inadvertently stumbled upon a world without meaning. In order to explain how this has happened, the paper first explores Snow's challenge: to describe the second law of thermodynamics. The paper then provides a description of entropy that is neutral with regard to thermodynamics and information, …

Development And Demonstration Of A Pico-Watt Calorimeter For Optical Absorption Spectroscopy, Behshad Roshanzadeh

Optical Science and Engineering ETDs

An optical calorimeter for sensitive absorption measurements of non-radiative samples at 4 K was designed, built, and demonstrated. It consists of a cryostat cooled by a commercial pulse tube (PTC) refrigerator, a measurement chamber housing the sample and thermometers, and various fiber-coupled light sources. By employing measures to damp mechanical noise from the environment and active temperature stabilization of critical components of the instrument temperature noise as low as 6 nK/√Hz at 50 mHz was achieved under 15 mW of optical excitation. An optical absorption induced temperature increase of the sample as small as 2.5 nK could be resolved using …

Learning Assistant And Instructor Communication: Impacts On Perceived Efficacy, Jahangir Rassouli, Laura Ríos

Physics

The Learning Assistant (LA) Model was co-developed by Richard McCray and Valerie Otero at the University of Colorado Boulder in 2003. In this model, senior undergraduate students serve as facilitators for group discussion in lower-division courses, and employ evidenced-based practices for promoting inquiry and active learning [1]. Since its inception, the LA model has grown to various departments, disciplines, and universities.

At California Polytechnic State University San Luis Obispo (Cal Poly), the LA program in the physics department is still in its early stages. As such, it is an environment rich for exploration into the affordances, limitations, and benefits of …

Visualization Of Brown Fat Using X-Ray Dark Field Imaging, Troy D. Jacobs

LSU Master's Theses

Introduction: Obesity has become a major societal issue. Many researchers are looking for ways to combat this growing epidemic. Brown adipose tissue (BAT) might be a way to help individuals overcome the challenges associated with weight loss and maintenance of weight loss, but a better understanding of BAT and how to control and utilize it is needed. BAT differs from white adipose tissue (WAT) in that BAT is rich with mitochondria and therefore is metabolically active. BAT is a source of non-shivering thermogenesis and can be activated both by cold exposure and pharmacologically. Current methods of assessing BAT activity are …

Noncontextuality Inequalities From Antidistinguishability, Matthew S. Leifer, Cristhiano Duarte

Mathematics, Physics, and Computer Science Faculty Articles and Research

Noncontextuality inequalities are usually derived from the distinguishability properties of quantum states, i.e., their orthogonality. Here, we show that antidistinguishability can also be used to derive noncontextuality inequalities. The Yu-Oh 13-ray noncontextuality inequality can be rederived and generalized as an instance of our antidistinguishability method. For some sets of states, the antidistinguishability method gives tighter bounds on noncontextual models than just considering orthogonality, and the Hadamard states provide an example of this. We also derive noncontextuality inequalities based on mutually unbiased bases and symmetric informationally complete positive operator-valued measures. Antidistinguishability based inequalities were initially discovered as overlap bounds for the …