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2020

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Articles 1291 - 1314 of 1314

Full-Text Articles in Physics

Shape Tuning Of Silicon Nano-Tip Arrays Through Reactive Ion Etching For Cold Field Emission, Giridhar Tulasi Ram Sankabathula Jan 2020

Shape Tuning Of Silicon Nano-Tip Arrays Through Reactive Ion Etching For Cold Field Emission, Giridhar Tulasi Ram Sankabathula

Graduate Research Theses & Dissertations

Large area silicon nano-tip arrays have been predominantly used as cold cathode electron sources in the wide range of field emission applications. Various fabrication methodologies have been developed over the decades to obtain sharp-pointed field emitters. In this thesis, we mainly emphasized on reproducing high aspect ratio field emitters and to study their surface topographical changes encountered through reactive ion etching. A discrete set of high-density field emitters have been fabricated over the large area surfaces through a three-step nanofabrication process. The surface curvatures of the obtained emitter tips are finely tuned with multiple oxidation cycles to achieve a tip’s …

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Nonlinear Integrable Optics Beam Dynamics Experimentand Diagnostics, Sebastian Szustkowski Jan 2020

Nonlinear Integrable Optics Beam Dynamics Experimentand Diagnostics, Sebastian Szustkowski

Graduate Research Theses & Dissertations

All present circular particle accelerators are built around linear focusing optics. Unavoidable nonlinear elements appear in accelerators, such as magnetic aberrations and space-charge effects, which are typically corrected using nonlinear magnets. However, these added nonlinearities degrade particle beam stability, and in most cases, the system becomes non-integrable. The Integrable Optics Test Accelerator (IOTA), at Fermi National Accelerator Laboratory (Fermilab), is a test bed to study beam dynamics in integrable lattices for both electron and proton beams, independently.This work presents experimental results of the nonlinear electron beam dynamics behavior in IOTA using an elliptical nonlinear magnet. The elliptical nonlinear magnet allows …

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Spatial Defects Nanoengineering For Bipolar Conductivity In Mos2, Xiaorui Zheng, Annalisa Calò, Tengfei Cao, Xiangyu Liu, Zhujun Huang, Paul Masih Das, Marija Drndic, Edoardo Albisetti, Francesco Lavini, Tai-De Li, Vishal Narang, William P. King, Michele Vittadello, Carmela Aruta, Davood Shahrjerdi, Elisa Riedo Jan 2020

Spatial Defects Nanoengineering For Bipolar Conductivity In Mos2, Xiaorui Zheng, Annalisa Calò, Tengfei Cao, Xiangyu Liu, Zhujun Huang, Paul Masih Das, Marija Drndic, Edoardo Albisetti, Francesco Lavini, Tai-De Li, Vishal Narang, William P. King, Michele Vittadello, Carmela Aruta, Davood Shahrjerdi, Elisa Riedo

Advanced Science Research Center

Understanding the atomistic origin of defects in two-dimensional transition metal dichalcogenides, their impact on the electronic properties, and how to control them is critical for future electronics and optoelectronics. Here, we demonstrate the integration of thermochemical scanning probe lithography (tc-SPL) with a flow-through reactive gas cell to achieve nanoscale control of defects in monolayer MoS2. The tc-SPL produced defects can present either p- or n-type doping on demand, depending on the used gasses, allowing the realization of field effect transistors, and p-n junctions with precise sub-μm spatial control, and a rectification ratio of over 104. Doping …

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Sequence-Coded Coherent Laser Ranging With High Detection Sensitivity, Keren Shemer, Gil Bashan, H Hagai Diamandi, Yosef London, Tzur Raanan, Yochai Israelashvili, Alon Charny, Itzik Cohen, Arik Bergman, Nadav Levanon, Avi Zadok Jan 2020

Sequence-Coded Coherent Laser Ranging With High Detection Sensitivity, Keren Shemer, Gil Bashan, H Hagai Diamandi, Yosef London, Tzur Raanan, Yochai Israelashvili, Alon Charny, Itzik Cohen, Arik Bergman, Nadav Levanon, Avi Zadok

Advanced Science Research Center

The compression of extended, coded sequences allows for laser ranging measurements with low peak power levels. Previous realizations of this approach were restricted by additive noise of direct, incoherent detection. In this work we bring together pulse sequence coding and optical coherent detection to achieve very high sensitivity. Collected sequences with an overall energy equivalent to only 800 photons are successfully compressed. The observed sensitivity agrees with analytic predictions. Compared with incoherent detection, measurement durations are reduced by four orders of magnitude. The protocol is suitable for laser ranging over tens of kilometers, depending on atmospheric conditions.

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Nonreciprocal Wavefront Manipulation In Synthetically Moving Metagratings, Younes Ra’Di, Andrea Alù Jan 2020

Nonreciprocal Wavefront Manipulation In Synthetically Moving Metagratings, Younes Ra’Di, Andrea Alù

Advanced Science Research Center

We introduce a metasurface platform for nonreciprocal wave manipulation. We study metagratings composed of nonreciprocal bianisotropic particles supporting synthetic motion, which enable nonreciprocal energy transfer between tailored Floquet channels with unitary efficiency. Based on this framework, we derive the required electromagnetic polarizabilities to realize a metagrating supporting space wave circulation with unitary efficiency for free-space radiation and design a microwave metagrating supporting this functionality. The proposed concept opens new research venues to control free-space radiation with high efficiency beyond the limits dictated by Lorentz reciprocity.

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Reconfigurable Floquet Elastodynamic Topological Insulator Based On Synthetic Angular Momentum Bias, Amir Darabi, Xiang Ni, Michael Leamy, Andrea Alù Jan 2020

Reconfigurable Floquet Elastodynamic Topological Insulator Based On Synthetic Angular Momentum Bias, Amir Darabi, Xiang Ni, Michael Leamy, Andrea Alù

Advanced Science Research Center

Originating with the discovery of the quantum Hall effect (QHE) in condensed matter physics, topological order has been receiving increased attention also for classical wave phenomena. Topological protection enables efficient and robust signal transport; mechanical topological insulators (TIs), in particular, are easy to fabricate and exhibit interfacial wave transport with minimal dissipation, even in the presence of sharp edges, defects, or disorder. Here, we report the experimental demonstration of a phononic crystal Floquet TI (FTI). Hexagonal arrays of circular piezoelectric disks bonded to a PLA substrate, shunted through negative electrical capacitance, and manipulated by external integrated circuits, provide the required …

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Edge-Oriented And Steerable Hyperbolic Polaritons In Anisotropic Van Der Waals Nanocavities, Zhigao Dai, Guangwei Hu, Guangyuan Si, Qingdong Ou, Qing Zhang, Sivacarendran Balendhran, Fahmida Rahman, Bao Yue Zhang, Jian Zhen Ou, Guogang Li, Andrea Alù, Cheng-Wei Qiu, Qiaoliang Bao Jan 2020

Edge-Oriented And Steerable Hyperbolic Polaritons In Anisotropic Van Der Waals Nanocavities, Zhigao Dai, Guangwei Hu, Guangyuan Si, Qingdong Ou, Qing Zhang, Sivacarendran Balendhran, Fahmida Rahman, Bao Yue Zhang, Jian Zhen Ou, Guogang Li, Andrea Alù, Cheng-Wei Qiu, Qiaoliang Bao

Advanced Science Research Center

Highly confined and low-loss polaritons are known to propagate isotropically over graphene and hexagonal boron nitride in the plane, leaving limited degrees of freedom in manipulating light at the nanoscale. The emerging family of biaxial van der Waals materials, such as α- MoO3 and V2O5, support exotic polariton propagation, as their auxiliary optical axis is in the plane. Here, exploiting this strong in-plane anisotropy, we report edge-tailored hyperbolic polaritons in patterned α-MoO3 nanocavities via real-space nanoimaging. We find that the angle between the edge orientation and the crystallographic direction significantly affects the optical response, …

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Suppressing Material Loss In The Visible And Near-Infrared Range For Functional Nanophotonics Using Bandgap Engineering, Mingsong Wang, Alex Krasnok, Sergey Lepeshov, Guangwei Hu, Taizhi Jiang, Jie Fang, Brian A. Korgel, Andrea Alù, Yuebing Zheng Jan 2020

Suppressing Material Loss In The Visible And Near-Infrared Range For Functional Nanophotonics Using Bandgap Engineering, Mingsong Wang, Alex Krasnok, Sergey Lepeshov, Guangwei Hu, Taizhi Jiang, Jie Fang, Brian A. Korgel, Andrea Alù, Yuebing Zheng

Advanced Science Research Center

All-dielectric nanostructures have recently opened exciting opportunities for functional nanophotonics, owing to their strong optical resonances along with low material loss in the near-infrared range. Pushing these concepts to the visible range is hindered by their larger absorption coefficient, thus encouraging the search for alternative dielectrics for nanophotonics. Here, we employ bandgap engineering to synthesize hydrogenated amorphous Si nanoparticles (a-Si:H NPs) offering ideal features for functional nanophotonics. We observe significant material loss suppression in a-Si:H NPs in the visible range caused by hydrogenation-induced bandgap renormalization, producing strong higher-order resonant modes in single NPs with Q factors up to ~100 in …

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Collective Near-Field Coupling And Nonlocal Phenomena In Infrared-Phononic Metasurfaces For Nano-Light Canalization, Peining Li, Guangwei Hu, Irene Dolado, Mykhailo Tymchenko, Cheng-Wei Qiu, Francisco Javier Alfaro-Mozaz, Fèlix Casanova, Luis E. Hueso, Song Liu, James H. Edgar, Saül Vélez, Andrea Alù, Rainer Hillenbrand Jan 2020

Collective Near-Field Coupling And Nonlocal Phenomena In Infrared-Phononic Metasurfaces For Nano-Light Canalization, Peining Li, Guangwei Hu, Irene Dolado, Mykhailo Tymchenko, Cheng-Wei Qiu, Francisco Javier Alfaro-Mozaz, Fèlix Casanova, Luis E. Hueso, Song Liu, James H. Edgar, Saül Vélez, Andrea Alù, Rainer Hillenbrand

Advanced Science Research Center

Polaritons – coupled excitations of photons and dipolar matter excitations – can propagate along anisotropic metasurfaces with either hyperbolic or elliptical dispersion. At the transition from hyperbolic to elliptical dispersion (corresponding to a topological transition), various intriguing phenomena are found, such as an enhancement of the photonic density of states, polariton canalization and hyperlensing. Here, we investigate theoretically and experimentally the topological transition, the polaritonic coupling and the strong nonlocal response in a uniaxial infrared-phononic metasurface, a grating of hexagonal boron nitride (hBN) nanoribbons. By hyperspectral infrared nanoimaging, we observe a synthetic transverse optical phonon resonance (strong collective near-field coupling …

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Magnetoquasistatic Resonances Of Small Dielectric Objects, Carlo Forestiere, Giovanni Miano, Guglielmo Rubinacci, Mariano Pascale, Antonello Tamburrino, Antonello Tamburrino, Roberto Tricarico, Salvatore Ventre Jan 2020

Magnetoquasistatic Resonances Of Small Dielectric Objects, Carlo Forestiere, Giovanni Miano, Guglielmo Rubinacci, Mariano Pascale, Antonello Tamburrino, Antonello Tamburrino, Roberto Tricarico, Salvatore Ventre

Advanced Science Research Center

A small dielectric object with positive permittivity may resonate when the free-space wavelength is large in comparison with the object dimensions if the permittivity is sufficiently high. We show that these resonances are described by the magnetoquasistatic approximation of the Maxwell's equations in which the normal component of the displacement current density field vanishes on the surface of the particle. They are associated to values of permittivities and frequencies for which source-free quasistatic magnetic fields exist, which are connected to the eigenvalues of a magnetostatic integral operator. We present the general physical properties of magnetoquasistatic resonances in dielectrics with arbitrary …

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Demonstration Of A Quantized Acoustic Octupole Topological Insulator, Xiang Ni, Mengyao Li, Matthew Weiner, Andrea Alù, Alexander B. Khanikaev Jan 2020

Demonstration Of A Quantized Acoustic Octupole Topological Insulator, Xiang Ni, Mengyao Li, Matthew Weiner, Andrea Alù, Alexander B. Khanikaev

Advanced Science Research Center

Recently introduced quantized multipole topological insulators (QMTIs) reveal new types of gapped boundary states, which themselves represent lower-dimensional topological phases and host symmetry protected zero-dimensional corner states. Inspired by these predictions, tremendous efforts have been devoted to the experimental observation of quantized quadrupole topological phase. However, due to stringent requirements of anti-commuting reflection symmetries, it is challenging to achieve higher-order quantized multipole moments, such as octupole moments, in a three-dimensional structure. Here, we overcome this challenge, and experimentally realize the acoustic analogue of a quantized octupole topological insulator using negatively coupled resonators. We confirm by first-principle studies that our design …

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Demonstration Of A Third-Order Hierarchy Of Topological States In A Three-Dimensional Acoustic Metamaterial, Matthew Weiner, Xiang Ni, Mengyao Li, Andrea Alù, Alexander B. Khanikaev Jan 2020

Demonstration Of A Third-Order Hierarchy Of Topological States In A Three-Dimensional Acoustic Metamaterial, Matthew Weiner, Xiang Ni, Mengyao Li, Andrea Alù, Alexander B. Khanikaev

Advanced Science Research Center

Classical wave systems have constituted an excellent platform for emulating complex quantum phenomena, such as demonstrating topological phenomena in photonics and acoustics. Recently, a new class of topological states localized in more than one dimension of a D-dimensional system, referred to as higher-order topological (HOT) states, has been reported, offering an even more versatile platform to confine and control classical radiation and mechanical motion. Here, we design and experimentally study a 3D topological acoustic metamaterial supporting third-order (0D) topological corner states along with second-order (1D) edge states and first-order (2D) surface states within the same topological bandgap, thus establishing …

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Sources And Characteristics Of Size-Resolved Particulate Organic Acids And Methanesulfonate In A Coastal Megacity: Manila, Philippines, Connor Stahl, Melliza Templonuevo Cruz, Paola Angela Bañaga, Grace Betito, Rachel A. Braun, Mojtaba Azadi Aghdam, Maria Obiminda L. Cambaliza, Genevieve Rose Lorenzo, Alexander B. Macdonald, Miguel Ricardo A. Hilario, Preciosa Corazon Pabroa, John Robin Yee, James Bernard Simpas, Armin Sorooshian Jan 2020

Sources And Characteristics Of Size-Resolved Particulate Organic Acids And Methanesulfonate In A Coastal Megacity: Manila, Philippines, Connor Stahl, Melliza Templonuevo Cruz, Paola Angela Bañaga, Grace Betito, Rachel A. Braun, Mojtaba Azadi Aghdam, Maria Obiminda L. Cambaliza, Genevieve Rose Lorenzo, Alexander B. Macdonald, Miguel Ricardo A. Hilario, Preciosa Corazon Pabroa, John Robin Yee, James Bernard Simpas, Armin Sorooshian

Physics Faculty Publications

A 16-month (July 2018–October 2019) dataset of size-resolved aerosol composition is used to examine the sources and characteristics of five organic acids (oxalate, succinate, adipate, maleate, phthalate) and methanesulfonate (MSA) in Metro Manila, Philippines. As one of the most polluted megacities globally, Metro Manila offers a view of how diverse sources and meteorology impact the relative amounts and size distributions of these species. A total of 66 sample sets were collected with a Micro-Orifice Uniform Deposit Impactor (MOUDI), of which 54 sets were analyzed for composition. Organic acids and MSA surprisingly were less abundant than in other global regions that …

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Brewster's Angle, Wontaek Kim Jan 2020

Brewster's Angle, Wontaek Kim

A with Honors Projects

No abstract provided.

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Evaluation Of The Activity Of Zn-65 Isotope And Radiation Dose Delivered To Drosophila Melanogaster, Wasiu Ajani Erinoso Jan 2020

Evaluation Of The Activity Of Zn-65 Isotope And Radiation Dose Delivered To Drosophila Melanogaster, Wasiu Ajani Erinoso

All Graduate Theses, Dissertations, and Other Capstone Projects

Radioactivity is a natural part of our environment. Ionizing radiation from radioactive materials can affect the life cycle of organisms; sometimes increase the rate of transition between cycle leading to the proliferation of cells as seen in some cancer cells or delay the rate of transition between cell cycle. A NaI detector is essential to determine the activity of a radioactive material. To determine the resolution of NaI detector and the efficiency of the geometry used for this experiment, quality control was done for NaI detector using 22Na reference source. The efficiency of the detector was used to verify the …

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Plasmonic Slab Waveguides: Theory & Application For Sensors, Anum Khattak Jan 2020

Plasmonic Slab Waveguides: Theory & Application For Sensors, Anum Khattak

Theses and Dissertations (Comprehensive)

Through surface plasmon polaritons (SPPs) that propagate along the interface between a metal and a dielectric material, plasmonic waveguides have the ability to confine light at subwavelength scale beyond the diffraction limit, which opens a promising platform to further downsize the active and passive photonic devices. The fields of the SPPs have maximum amplitude at the metal/dielectric interface and decay exponentially toward both media, where the penetration of the fields in the dielectric is very susceptible to the change in the refractive index of the dielectric. This makes surface plasmon resonance (SPR) a remarkable technique in sensor applications to investigate …

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Quantitative Analysis Of Human Blood Serum Using Vibrational Spectroscopy., Hugh Byrne, Franck Bonnier, Jennifer Mcintyre, Drishya Rajan Parachalil Jan 2020

Quantitative Analysis Of Human Blood Serum Using Vibrational Spectroscopy., Hugh Byrne, Franck Bonnier, Jennifer Mcintyre, Drishya Rajan Parachalil

Articles

Analysis of bodily fluids using vibrational spectroscopy has attracted increasing attention in recent years. In particular, infrared spectroscopic screening of blood products, particularly blood serum, for disease diagnostics has been advanced considerably, attracting commercial interests. However, analyses requiring quantification of endogenous constituents or exogenous agents in blood are less well advanced. Recent advances towards this end are reviewed, focussing on infrared and Raman spectroscopic analyses of human blood serum. The importance of spectroscopic analysis in the native aqueous environment is highlighted, and the relative merits of infrared absorption versus Raman spectroscopy are considered, in this context. It is argued that …

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Liposomal Encapsulation Of Silver Nanoparticles (Agnp) Improved Nanoparticle Uptake And Induced Redox Imbalance To Activate Caspase-Dependent Apoptosis, Azeez O. Yusef, Alan Casey Jan 2020

Liposomal Encapsulation Of Silver Nanoparticles (Agnp) Improved Nanoparticle Uptake And Induced Redox Imbalance To Activate Caspase-Dependent Apoptosis, Azeez O. Yusef, Alan Casey

Articles

Macrophages play a crucial role in several diseases’ development and progression, such as in cancer and arthritis through ROS generation and infammation. This makes macrophages a therapeutic target in these diseases. While silver nanoparticles (AgNP) have been widely used as an antibacterial and investigated as anticancer, its potential against macrophages may be limited due to its inherent oxidative mechanism. Here we encapsulated AgNP in a dipalmitoyl-phosphatidyl choline (DPPC) liposome (forming Lipo-AgNP) to suppress AgNP-induced ROS and enhance its cytotoxicity against THP1-diferentiated macrophages (TDM). Our fndings showed that while Lipo-AgNP had signifcantly more of a cytotoxic efect on TDMs (p< 0.01), it also signifcantly suppressed AgNP induced ROS generation and unexpectedly suppressed reduced glutathione (GSH) levels (p< 0.05) resulting in a redox imbalance in comparison to the unexposed control TDMs. Lipo-AgNP was also found to cause an increase DNA damage through H2AX histone phosphorylation and inhibition of Bcl-2 protein expression. This increased the Bax/Bcl2 ratio causing possible release of cytochrome C and subsequent caspase 3/7-dependent apoptosis. It was found that the diference between the mechanism of AgNP and Lipo-AgNP cytotoxicity may have been through the signifcantly increased Lipo-AgNP uptake by the TDMs as early as 30 min post-exposure (p< 0.05), changing the nanoparticle pharmacokinetic. In conclusion, the improved uptake of AgNP within the liposome caused ROS-independent caspase activation induced by Lipo-AgNP and this was facilitated by increased DNA damage, the induced redox imbalance and an increased Bax/Bcl-2 ratio.

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Special Section Guest Editorial: Machine Learning In Optics, Jonathan Howe, Travis Axtell, Khan Iftekharuddin Jan 2020

Special Section Guest Editorial: Machine Learning In Optics, Jonathan Howe, Travis Axtell, Khan Iftekharuddin

Electrical & Computer Engineering Faculty Publications

This guest editorial summarizes the Special Section on Machine Learning in Optics.

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Gw190814: Gravitational Waves From The Coalescence Of A 23 Solar Mass Black Hole With A 2.6 Solar Mass Compact Object, R. Abbott, T. D. Abbott, S. Abraham, A. Aich, G. Bissenbayeva, Teviet Creighton, Mario C. Diaz, Soma Mukherjee Jan 2020

Gw190814: Gravitational Waves From The Coalescence Of A 23 Solar Mass Black Hole With A 2.6 Solar Mass Compact Object, R. Abbott, T. D. Abbott, S. Abraham, A. Aich, G. Bissenbayeva, Teviet Creighton, Mario C. Diaz, Soma Mukherjee

Physics & Astronomy Faculty Publications

We report the observation of a compact binary coalescence involving a 22.2 - 24.3 M⊙ black hole and a compact object with a mass of 2.50 - 2.67 M⊙ (all measurements quoted at the 90% credible level). The gravitational-wave signal, GW190814, was observed during LIGO's and Virgo's third observing run on August 14, 2019 at 21:10:39 UTC and has a signal-to-noise ratio of 25 in the three-detector network. The source was localized to 18.5 deg2 at a distance of 241+41−45 Mpc; no electromagnetic counterpart has been confirmed to date. The source has the most unequal mass ratio yet measured with …

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Special Issue On The Third Workshop On Biological Mentality, Kenneth A. Augustyn Jan 2020

Special Issue On The Third Workshop On Biological Mentality, Kenneth A. Augustyn

Michigan Tech Publications, Part 1

The Third Workshop on Biological Mentality was held from September 23, 2019 to March 2, 2020 as a series of twenty-one Monday online conferencing sessions, each consisting of a talk followed by a Q&A discussion. Like the two previous workshops [1, 2], the objective of this workshop was to seek a deeper level of understanding the physical foundations of biological mentality (whether conscious or nonconscious).

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A Joint Fermi-Gbm And Ligo/Virgo Analysis Of Compact Binary Mergers From The First And Second Gravitational-Wave Observing Runs, R. Hamburg, C. Fletcher, E. Burns, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Wenhui Wang, Adam Zadrozny Jan 2020

A Joint Fermi-Gbm And Ligo/Virgo Analysis Of Compact Binary Mergers From The First And Second Gravitational-Wave Observing Runs, R. Hamburg, C. Fletcher, E. Burns, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Karla E. Ramirez, Wenhui Wang, Adam Zadrozny

Physics & Astronomy Faculty Publications

We present results from offline searches of Fermi Gamma-ray Burst Monitor (GBM) data for gamma-ray transients coincident with the compact binary coalescences observed by the gravitational-wave (GW) detectors Advanced LIGO and Advanced Virgo during their first and second observing runs. In particular, we perform follow-up for both confirmed events and low significance candidates reported in the LIGO/Virgo catalog GWTC-1. We search for temporal coincidences between these GW signals and GBM-triggered gamma-ray bursts (GRBs). We also use the GBM Untargeted and Targeted subthreshold searches to find coincident gamma-rays below the onboard triggering threshold. This work implements a refined statistical approach by …

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Wallaby – An Ska Pathfinder Hisurvey, B. S. Koribalski, L. Stavely-Smith, Tobias Westmeier, P. Serra, K. Spekkens, O. I. Wang, C. D. P. Lagos, D. Obreschkow, E. V. Ryan-Webber, Juan P. Madrid Jan 2020

Wallaby – An Ska Pathfinder Hisurvey, B. S. Koribalski, L. Stavely-Smith, Tobias Westmeier, P. Serra, K. Spekkens, O. I. Wang, C. D. P. Lagos, D. Obreschkow, E. V. Ryan-Webber, Juan P. Madrid

Physics & Astronomy Faculty Publications

The Widefield ASKAP L-band Legacy All-sky Blind surveY (WALLABY) is a next-generation survey of neutral hydrogen (HI) in the Local Universe. It uses the widefield, high-resolution capability of the Australian Square Kilometer Array Pathfinder (ASKAP), a radio interferometer consisting of 36 x 12-m dishes equipped with Phased-Array Feeds (PAFs), located in an extremely radio-quiet zone in Western Australia. WALLABY aims to survey three-quarters of the sky (-90 degr < Dec < +30 degr) to a redshift of z < 0.26, and generate spectral line image cubes at ~30 arcsec resolution and ~1.6 mJy/beam per 4 km/s channel sensitivity. ASKAP's instantaneous field of view at 1.4 GHz, delivered by the PAF's 36 beams, is about 30 sq deg. At an integrated signal-to-noise ratio of five, WALLABY is expected to detect over half a million galaxies with a mean redshift of z ~ 0.05 (~200 Mpc). The scientific goals of WALLABY include: (a) a census of gas-rich galaxies in the vicinity of the Local Group; (b) a study of the HI properties of galaxies, groups and clusters, in particular the influence of the environment on galaxy evolution; and (c) the refinement of cosmological parameters using the spatial and redshift distribution of low-bias gas-rich galaxies. For context we provide an overview of previous large-scale HI surveys. Combined with existing and new multi-wavelength sky surveys, WALLABY will enable an exciting new generation of panchromatic studies of the Local Universe. - First results from the WALLABY pilot survey are revealed, with initial data products publicly available in the CSIRO ASKAP Science Data Archive (CASDA).

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Global Research Productivity In Nuclear Waste Management: A Scientometric Analysis, Fayaz Ahmad Loan, Ufaira Yaseen Jan 2020

Global Research Productivity In Nuclear Waste Management: A Scientometric Analysis, Fayaz Ahmad Loan, Ufaira Yaseen

Library Philosophy and Practice (e-journal)

Scientometrics has emerged as one of the prominent and fast-growing fields in the Library and Information Sciences. The present study also deals with the scientometric aspect of one of the prominent fields of Nuclear Science and Technology i.e. Nuclear Waste Management. The data for the said study has been collected from the Web of Science database over the period 1989-2019. The results reveal that a total of 1824 publications have been published on Nuclear Waste Management and the highest number has been contributed by the USA (23.7%) of the total global output. Most of the Nuclear Waste Management literature …

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