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Articles 61 - 90 of 325
Full-Text Articles in Physics
Characterization Of Water-Soluble Inorganic Ions And Carbonaceous Aerosols In The Urban Atmosphere In Amman, Jordan, Afnan Al-Hunaiti, Zaid Bakri, Xinyang Li, Lian Duan, Asal Al-Abdallat, Andres Alastuey, Mar Viana, Sharif Arar, Tuukka Petäjä, Tareq Hussein
Characterization Of Water-Soluble Inorganic Ions And Carbonaceous Aerosols In The Urban Atmosphere In Amman, Jordan, Afnan Al-Hunaiti, Zaid Bakri, Xinyang Li, Lian Duan, Asal Al-Abdallat, Andres Alastuey, Mar Viana, Sharif Arar, Tuukka Petäjä, Tareq Hussein
Michigan Tech Publications
The urban particulate matter (PM) carbonaceous and water-soluble ions were investigated in Amman, Jordan during May 2018–March 2019. The PM2.5 total carbon (TC) annual mean was 7.6 ± 3.6 μg/m3 (organic carbon (OC) 5.9 ± 2.8 μg/m3 and elemental carbon (EC) 1.7 ± 1.1 μg/m3), which was about 16.3% of the PM2.5. The PM10 TC annual mean was 8.4 ± 3.9 μg/m3 (OC 6.5 ± 3.1 μg/m3 and elemental carbon (EC) 1.9 ± 1.1 μg/m3), about 13.3% of the PM10. The PM2.5 total water-soluble ions annual mean was 7.9 ± 1.9 μg/m3 (about 16.9%), and that of the PM10 was …
Exceptional Points Induced By Unidirectional Coupling In Electronic Circuits, Wenzheng Zhao, Yeang Zhang, Zixuan Gao, Delong Peng, Jun Long Kou, Yan Qing Lu, Ramy El-Ganainy, Şahin K. Özdemir, Qi Zhong
Exceptional Points Induced By Unidirectional Coupling In Electronic Circuits, Wenzheng Zhao, Yeang Zhang, Zixuan Gao, Delong Peng, Jun Long Kou, Yan Qing Lu, Ramy El-Ganainy, Şahin K. Özdemir, Qi Zhong
Michigan Tech Publications
Exceptional points in non-Hermitian systems have attracted considerable attention due to their novel applications in several fields such as optics, electronics, and mechanics. Typically, exceptional points are constructed through gain and loss modulation or dissipative coupling within the framework of parity-time symmetry or anti-parity-time symmetry. Recent demonstration of unidirectional coupling in optical resonators to create exceptional points has offered an alternative approach. This study extends this concept to electronic circuits, examining exceptional points that emerge in unidirectionally coupled LC circuits. We show that this circuit undergoes resonance frequency splitting that exhibits either linear or square-root scaling with the strength of …
Large-Scale Cosmic-Ray Anisotropies With 19 Yr Of Data From The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, B. Fick, K. Nguyen, D. Nitz, Et Al.
Large-Scale Cosmic-Ray Anisotropies With 19 Yr Of Data From The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, B. Fick, K. Nguyen, D. Nitz, Et Al.
Michigan Tech Publications
Results are presented for the measurement of large-scale anisotropies in the arrival directions of ultra–high-energy cosmic rays detected at the Pierre Auger Observatory during 19 yr of operation, prior to AugerPrime, the upgrade of the observatory. The 3D dipole amplitude and direction are reconstructed above 4 EeV in four energy bins. Besides the established dipolar anisotropy in R.A. above 8 EeV, the Fourier amplitude of the 8–16 EeV energy bin is now also above the 5σ discovery level. No time variation of the dipole moment above 8 EeV is found, setting an upper limit to the rate of change …
The Green Monster Hiding In Front Of Cas A: Jwst Reveals A Dense And Dusty Circumstellar Structure Pockmarked By Ejecta Interactions, Ilse De Looze, Dan Milisavljevic, Tea Temim, Danielle Dickinson, Robert Fesen, Richard G. Arendt, Judy Schmidt, Et Al.
The Green Monster Hiding In Front Of Cas A: Jwst Reveals A Dense And Dusty Circumstellar Structure Pockmarked By Ejecta Interactions, Ilse De Looze, Dan Milisavljevic, Tea Temim, Danielle Dickinson, Robert Fesen, Richard G. Arendt, Judy Schmidt, Et Al.
Michigan Tech Publications
JWST observations of the young Galactic supernova remnant Cassiopeia A revealed an unexpected structure seen as a green emission feature in colored composite MIRI F1130W and F1280W images—hence dubbed the Green Monster—that stretches across the central parts of the remnant in projection. Combining the kinematic information from NIRSpec and the MIRI Medium Resolution Spectrograph with the multiwavelength imaging from NIRCam and MIRI, we associate the Green Monster with circumstellar material (CSM) that was lost during an asymmetric mass-loss phase. MIRI images are dominated by dust emission, but their spectra show emission lines from Ne, H, and Fe with low radial …
Spectral Study Of Very-High-Energy Gamma Rays From Ss 433 With Hawc, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, S. Groetsch, P. Hüntemeyer, R. Turner, Zhenlin Wang, Et Al.
Spectral Study Of Very-High-Energy Gamma Rays From Ss 433 With Hawc, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, S. Groetsch, P. Hüntemeyer, R. Turner, Zhenlin Wang, Et Al.
Michigan Tech Publications
Very-high-energy (0.1-100 TeV) gamma-ray emissions were observed in High-Altitude Water Cherenkov (HAWC) data from the lobes of the microquasar SS 433, making them the first set of astrophysical jets that were resolved at TeV energies. In this work, we update the analysis of SS 433 using 2565 days of data from the HAWC observatory. Our analysis reports the detection of a point-like source in the east lobe at a significance of 6.6σ and in the west lobe at a significance of 8.2σ. For each jet lobe, we localize the gamma-ray emission and identify a best-fit position. The locations are close …
Search For Joint Multimessenger Signals From Potential Galactic Cosmic-Ray Accelerators With Hawc And Icecube, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, S. Groetsch, Petra Huentemeyer, R. Turner, X. Wang, Et. Al
Search For Joint Multimessenger Signals From Potential Galactic Cosmic-Ray Accelerators With Hawc And Icecube, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, S. Groetsch, Petra Huentemeyer, R. Turner, X. Wang, Et. Al
Michigan Tech Publications
The origin of high-energy galactic cosmic rays is yet to be understood, but some galactic cosmic-ray accelerators can accelerate cosmic rays up to PeV energies. The high-energy cosmic rays are expected to interact with the surrounding material or radiation, resulting in the production of gamma-rays and neutrinos. To optimize for the detection of such associated production of gamma-rays and neutrinos for a given source morphology and spectrum, a multimessenger analysis that combines gamma-rays and neutrinos is required. In this study, we use the MultiMission Maximum Likelihood framework with IceCube Maximum Likelihood Analysis software and HAWC Accelerated Likelihood to search for …
Analysis Of The Emission And Morphology Of The Pulsar Wind Nebula Candidate Hawc J2031+415, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A.Ayala Solares, R. Babu, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, X. Wang, Et Al.
Analysis Of The Emission And Morphology Of The Pulsar Wind Nebula Candidate Hawc J2031+415, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A.Ayala Solares, R. Babu, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, X. Wang, Et Al.
Michigan Tech Publications
The first TeV γ-ray source with no lower energy counterparts, TeV J2032+4130, was discovered by HEGRA. It appears in the third HAWC catalog as 3HWC J2031+415 and it is a bright TeV γ-ray source whose emission has previously been resolved as two sources: HAWC J2031+415 and HAWC J2030+409. While HAWC J2030+409 has since been associated with the Fermi Large Area Telescope Cygnus Cocoon, no such association for HAWC J2031+415 has yet been found. In this work, we investigate the spectrum and energy-dependent morphology of HAWC J2031+415. We associate HAWC J2031+415 with a γ-ray binary system containing the pulsar PSR J2032+4127 …
Testing The Molecular Cloud Paradigm For Ultra-High-Energy Gamma Ray Emission From The Direction Of Snr G106.3+2.7, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, X. Wang, Et Al.
Testing The Molecular Cloud Paradigm For Ultra-High-Energy Gamma Ray Emission From The Direction Of Snr G106.3+2.7, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, R. Babu, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, X. Wang, Et Al.
Michigan Tech Publications
Context. Supernova remnants (SNRs) are believed to be capable of accelerating cosmic rays (CRs) to PeV energies. SNR G106.3+2.7 is a prime PeVatron candidate. It is formed by a head region, where the pulsar J2229+6114 and its boomerang-shaped pulsar wind nebula are located, and a tail region containing SN ejecta. The lack of observed gamma ray emission from the two regions of this SNR has made it difficult to assess which region would be responsible for the PeV CRs. Aims. We aim to characterize the very-high-energy (VHE, 0.1-100 TeV) gamma ray emission from SNR G106.3+2.7 by determining the morphology and …
Large-Scale Cosmic-Ray Anisotropies With 19yr Of Data From The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, K. Nguyen, D. Nitz, Et Al.
Large-Scale Cosmic-Ray Anisotropies With 19yr Of Data From The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, K. Nguyen, D. Nitz, Et Al.
Michigan Tech Publications
Results are presented for the measurement of large-scale anisotropies in the arrival directions of ultra–high-energy cosmic rays detected at the Pierre Auger Observatory during 19 yr of operation, prior to AugerPrime, the upgrade of the observatory. The 3D dipole amplitude and direction are reconstructed above 4 EeV in four energy bins. Besides the established dipolar anisotropy in R.A. above 8 EeV, the Fourier amplitude of the 8–16 EeV energy bin is now also above the 5σ discovery level. No time variation of the dipole moment above 8 EeV is found, setting an upper limit to the rate of change of …
Theoretical Advances In Predicting The Thermoelectric Performance Of Materials, Mukesh Jakhar, Poonam Chauhan, Ashok Kumar, Ravindra Pandey
Theoretical Advances In Predicting The Thermoelectric Performance Of Materials, Mukesh Jakhar, Poonam Chauhan, Ashok Kumar, Ravindra Pandey
Michigan Tech Publications
Eco-friendly and high-performance thermoelectric materials have proven effective in converting heat energy into electricity. Theoretical methods for understanding the transport mechanisms of electrons and phonons play a vital role in predicting the overall thermoelectric performance of a given material. In this perspective, we review recent advances in theoretical methods for predicting electron and phonon transport properties in materials. In addition, we highlight the various methodologies adopted to estimate the electronic relaxation time and identify challenges and potential directions. The in-depth understanding obtained from these theoretical explorations will lead researchers to rely on computational methods to screen novel thermoelectric materials for …
Multiwavelength Investigation Of Γ-Ray Source Mgro J1908+06 Emission Using Fermi-Lat, Veritas And Hawc, A. Acharyya, C. B. Adams, P. Bangale, J. T. Bartkoske, W. Benbow, J. H. Buckley, R. Babu, S. Groetsch, R. Turner, X. Wang, Et. Al
Multiwavelength Investigation Of Γ-Ray Source Mgro J1908+06 Emission Using Fermi-Lat, Veritas And Hawc, A. Acharyya, C. B. Adams, P. Bangale, J. T. Bartkoske, W. Benbow, J. H. Buckley, R. Babu, S. Groetsch, R. Turner, X. Wang, Et. Al
Michigan Tech Publications
This paper investigates the origin of the γ-ray emission from MGRO J1908+06 in the GeV-TeV energy band. By analyzing the data collected by the Fermi Large Area Telescope, the Very Energetic Radiation Imaging Telescope Array System, and High Altitude Water Cherenkov, with the addition of spectral data previously reported by LHAASO, a multiwavelength study of the morphological and spectral features of MGRO J1908+06 provides insight into the origin of the γ-ray emission. The mechanism behind the bright TeV emission is studied by constraining the magnetic field strength, the source age, and the distance through detailed broadband modeling. Both spectral shape …
In Vitro Profiling Of The Antiviral Peptide Tat-I24, Theodhora Ziu, Ezgi Sambur, Zsolt Ruzsics, Hartmut Hengel, Reingard Grabherr, Siegfried Hofinger, Hanna Harant
In Vitro Profiling Of The Antiviral Peptide Tat-I24, Theodhora Ziu, Ezgi Sambur, Zsolt Ruzsics, Hartmut Hengel, Reingard Grabherr, Siegfried Hofinger, Hanna Harant
Michigan Tech Publications
The synthetic peptide TAT-I24 (GRKKRRQRRRPPQCLAFYACFC) exerts antiviral activity against several double-stranded (ds) DNA viruses, including herpes simplex viruses, cytomegalovirus, some adenoviruses, vaccinia virus and SV40 polyomavirus. In the present study, in vitro profiling of this peptide was performed with the aim of characterizing and improving its properties for further development. As TAT-I24 contains three free cysteine residues, a potential disadvantageous feature, peptide variants with replacements or deletions of specific residues were generated and tested in various cell systems and by biochemical analyses. Some cysteine replacements had no impact on the antiviral activity, such as the deletion of cysteine 14, which …
Search For Photons Above 1018 Ev By Simultaneously Measuring The Atmospheric Depth And The Muon Content Of Air Showers At The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, N. Nguyen, D. Nitz
Search For Photons Above 1018 Ev By Simultaneously Measuring The Atmospheric Depth And The Muon Content Of Air Showers At The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, N. Nguyen, D. Nitz
Michigan Tech Publications
The Pierre Auger Observatory is the most sensitive instrument to detect photons with energies above 1017 eV. It measures extensive air showers generated by ultrahigh energy cosmic rays using a hybrid technique that exploits the combination of a fluorescence detector with a ground array of particle detectors. The signatures of a photon-induced air shower are a larger atmospheric depth of the shower maximum (Xmax) and a steeper lateral distribution function, along with a lower number of muons with respect to the bulk of hadron-induced cascades. In this work, a new analysis technique in the energy interval between 1 and 30 …
Observation Of The Galactic Center Pevatron Beyond 100 Tev With Hawc, A. Albert, R. Alfaro, C. Alvarez, A. Andrés, J. C. Arteaga-Velázquez, D. Avila Rojas, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, X. Wang, Et. Al
Observation Of The Galactic Center Pevatron Beyond 100 Tev With Hawc, A. Albert, R. Alfaro, C. Alvarez, A. Andrés, J. C. Arteaga-Velázquez, D. Avila Rojas, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, X. Wang, Et. Al
Michigan Tech Publications
We report an observation of ultrahigh-energy (UHE) gamma rays from the Galactic center (GC) region, using 7 yr of data collected by the High-Altitude Water Cherenkov (HAWC) Observatory. The HAWC data are best described as a point-like source (HAWC J1746-2856) with a power-law spectrum ( d N / d E = ϕ E / 26 TeV γ ), where γ = −2.88 ± 0.15stat − 0.1sys and ϕ = 1.5 × 10−15 (TeV cm2 s)−1 ± 0.3 stat − 0.13 sys + 0.08 sys extending from 6 to 114 TeV. We find no evidence of a spectral cutoff up to …
Ion-Induced Cloud Modulation Through New Particle Formation And Runaway Cloud Condensation Nuclei Production, Kamal Kant Chandrakar, Will Cantrell, Raymond Shaw
Ion-Induced Cloud Modulation Through New Particle Formation And Runaway Cloud Condensation Nuclei Production, Kamal Kant Chandrakar, Will Cantrell, Raymond Shaw
Michigan Tech Publications
Cloud formation in the Pi Convection-Cloud Chamber is achieved via ionization in humid conditions, without the injection of aerosol particles to serve as cloud condensation nuclei (CCN). Abundant ions, turbulence, and supersaturated water vapor combine to produce new particles, which grow to become CCN sized and eventually are activated to form clouds. Coupling between the new particle formation and cloud droplets causes predator-prey type oscillations in aerosol and droplet concentrations under turbulent conditions. Leading terms are identified in the budgets for Aitken and accumulation mode aerosols and for cloud droplets. The cloud coupling is proposed to be a result of …
Implementing Reactivity In Molecular Dynamics Simulations With Harmonic Force Fields, Jordan J. Winetrout, Krishan Kanhaiya, Josh Kemppainen, Pieter J. In ‘T Veld, Geeta Sachdeva, Ravindra Pandey, Behzad Damirchi, Adri Van Duin, Gregory Odegard, Hendrik Heinz
Implementing Reactivity In Molecular Dynamics Simulations With Harmonic Force Fields, Jordan J. Winetrout, Krishan Kanhaiya, Josh Kemppainen, Pieter J. In ‘T Veld, Geeta Sachdeva, Ravindra Pandey, Behzad Damirchi, Adri Van Duin, Gregory Odegard, Hendrik Heinz
Michigan Tech Publications
The simulation of chemical reactions and mechanical properties including failure from atoms to the micrometer scale remains a longstanding challenge in chemistry and materials science. Bottlenecks include computational feasibility, reliability, and cost. We introduce a method for reactive molecular dynamics simulations using a clean replacement of non-reactive classical harmonic bond potentials with reactive, energy-conserving Morse potentials, called the Reactive INTERFACE Force Field (IFF-R). IFF-R is compatible with force fields for organic and inorganic compounds such as IFF, CHARMM, PCFF, OPLS-AA, and AMBER. Bond dissociation is enabled by three interpretable Morse parameters per bond type and zero energy upon disconnect. Use …
Performance Of The Hawc Observatory And Tev Gamma-Ray Measurements Of The Crab Nebula With Improved Extensive Air Shower Reconstruction Algorithms, A. Albert, R. Alfaro, C. Alvarez, A. Andrés, J. C. Arteaga-Velázquez, D. Avila Rojas, S. Groetsch, P. Hüntemeyer, R. Turner, X. Wang, Et Al.
Performance Of The Hawc Observatory And Tev Gamma-Ray Measurements Of The Crab Nebula With Improved Extensive Air Shower Reconstruction Algorithms, A. Albert, R. Alfaro, C. Alvarez, A. Andrés, J. C. Arteaga-Velázquez, D. Avila Rojas, S. Groetsch, P. Hüntemeyer, R. Turner, X. Wang, Et Al.
Michigan Tech Publications
The High-Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory, located on the side of the Sierra Negra volcano in Mexico, has been fully operational since 2015. The HAWC collaboration has recently significantly improved their extensive air shower reconstruction algorithms, which has notably advanced the observatory performance. The energy resolution for primary gamma rays with energies below 1 TeV was improved by including a noise-suppression algorithm. Corrections have also been made to systematic errors in direction fitting related to the detector and shower plane inclinations, O ( 0 .° 1 ) biases in highly inclined showers, and enhancements to the core reconstruction. The …
Strain And Substrate-Induced Electronic Properties Of Novel Mixed Anion-Based 2d Schx2 (X = I/Br) Semiconductors, Ashima Rawat, Ravindra Pandey
Strain And Substrate-Induced Electronic Properties Of Novel Mixed Anion-Based 2d Schx2 (X = I/Br) Semiconductors, Ashima Rawat, Ravindra Pandey
Michigan Tech Publications
Exploration of compounds featuring multiple anions beyond the single-oxide ion, such as oxyhalides and oxyhydrides, offers an avenue for developing materials with the prospect of novel functionality. In this paper, we present the results for a mixed anion layered material, ScHX2 (X: Br, I) based on density functional theory. The result predicted the ScHX2 (X: Br, I) monolayers to be stable and semiconducting. Notably, the electronic and mechanical properties of the ScHX2 monolayers are comparable to well-established 2D materials like graphene and MoS2, rendering them highly suitable for electronic devices. Additionally, these monolayers exhibit an ability to adjust their band …
Magnetization And Age Of Ca. 544 Ma Syenite, Eastern Canada: Evidence For Renewal Of The Geodynamo, Tinghong Zhou, Mauricio Ibañez-Mejia, Richard K. Bono, Rory D. Cottrell, Wouter Bleeker, Kenneth P. Kodama, Wentao Huang, Eric G. Blackman, Francis Nimmo, Aleksey Smirnov, John A. Tarduno
Magnetization And Age Of Ca. 544 Ma Syenite, Eastern Canada: Evidence For Renewal Of The Geodynamo, Tinghong Zhou, Mauricio Ibañez-Mejia, Richard K. Bono, Rory D. Cottrell, Wouter Bleeker, Kenneth P. Kodama, Wentao Huang, Eric G. Blackman, Francis Nimmo, Aleksey Smirnov, John A. Tarduno
Michigan Tech Publications
The ca. 565 Ma Ediacaran geodynamo was highly unusual, producing an ultralow field 10 times weaker than present-day value of 8 x 1022 A m2. A ∼5 times rise in field strength is seen in time-averaged single crystal paleointensity data of ca. 532 Ma Early Cambrian anorthosites of Oklahoma (USA). The field increase could record the onset of inner core nucleation predicted by thermal evolution and numerical dynamo models. Here, we examine the renewal of the geodynamo through zircon U-Pb geochronology and single crystal paleointensity studies of plagioclase from the Chatham-Grenville syenite intrusion in the Grenville Province (Canada). U-Pb data …
Evidence For Rapid Variability At High Energies In Grbs, E. Casey Aldrich, Robert J. Nemiroff
Evidence For Rapid Variability At High Energies In Grbs, E. Casey Aldrich, Robert J. Nemiroff
Michigan Tech Publications
Intrinsic variability was searched for in arrival times of six gamma-ray bursts (GRBs) at high energies – between 30 MeV and 2 GeV – detected by the Fermi satellite’s Large Area Telescope (LAT). The GRBs were selected from the Fermi LAT catalogue with preference for events with numerous photons, a strong initial pulse, and measured redshifts. Three long GRBs and three short GRBs were selected and tested. Two different variability-detection algorithms were deployed, one counting photons in pairs, and the other multiplying time gaps between photons. In both tests, a real GRB was compared to 1000 Monte Carlo versions of …
Deep Space Observations Of Conditionally Averaged Global Reflectance Patterns, Alexander Kostinski, Alexander Marshak, Tamás Várnai
Deep Space Observations Of Conditionally Averaged Global Reflectance Patterns, Alexander Kostinski, Alexander Marshak, Tamás Várnai
Michigan Tech Publications
The Deep Space Climate Observatory (DSCOVR) spacecraft drifts about the Lagrangian point ≈ 1.4 − 1.6 × 106 km from Earth, where its Earth Polychromatic Imaging Camera (EPIC) observes the entire sunlit face of Earth every 1–2 h. In an attempt to detect “signals,” i.e., longer-term changes and semi-permanent features such as the ever-present ocean glitter, while suppressing geographic “noise,” in this study, we introduce temporally and conditionally averaged reflectance images, performed on a fixed grid of pixels and uniquely suited to the DSCOVR/EPIC observational circumstances. The resulting images (maps), averaged in time over months and conditioned on surface/cover type …
Lunar: Automated Input Generation And Analysis For Reactive Lammps Simulations, Josh Kemppainen, Jacob R. Gissinger, S. Gowtham, Gregory Odegard
Lunar: Automated Input Generation And Analysis For Reactive Lammps Simulations, Josh Kemppainen, Jacob R. Gissinger, S. Gowtham, Gregory Odegard
Michigan Tech Publications
Generating simulation-ready molecular models for the LAMMPS molecular dynamics (MD) simulation software package is a difficult task and impedes the more widespread and efficient use of MD in materials design and development. Fixed-bond force fields generally require manual assignment of atom types, bonded interactions, charges, and simulation domain sizes. A new LAMMPS pre- and postprocessing toolkit (LUNAR) is presented that efficiently builds molecular systems for LAMMPS. LUNAR automatically assigns atom types, generates bonded interactions, assigns charges, and provides initial configuration methods to generate large molecular systems. LUNAR can also incorporate chemical reactivity into simulations by facilitating the use of the …
Thz Radar Observations Of Hydrometeors In A Spray Chamber, Zeen Zhu, Fan Yang, Edward Luke, Elise Rosky, Katia Lamer, Pavlos Kollias
Thz Radar Observations Of Hydrometeors In A Spray Chamber, Zeen Zhu, Fan Yang, Edward Luke, Elise Rosky, Katia Lamer, Pavlos Kollias
Michigan Tech Publications
A THz radar, with its wide bandwidth, is capable of high-resolution imaging down to the centimeter scale. In this study, a THz radar is applied to detect hydrometeors generated in a spray chamber. The observed backscattering signals show fluctuations at centimeter scales, indicating various hydrometeor distribution patterns along the radar beam. A co-located High-Speed Imaging (HSI) sensor is used to measure the Drop Size Distributions (DSD) in the spray chamber. The radar sampling beam is well aligned with the HSI probes, allowing an objective comparison between the remote sensing and in situ observations. In this study, the observed radar power …
Testing Hadronic-Model Predictions Of Depth Of Maximum Of Air-Shower Profiles And Ground-Particle Signals Using Hybrid Data Of The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, K. Nguyen, D. Nitz, Et Al.
Testing Hadronic-Model Predictions Of Depth Of Maximum Of Air-Shower Profiles And Ground-Particle Signals Using Hybrid Data Of The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, K. Nguyen, D. Nitz, Et Al.
Michigan Tech Publications
We test the predictions of hadronic interaction models regarding the depth of maximum of air-shower profiles, Xmax, and ground-particle signals in water-Cherenkov detectors at 1000 m from the shower core, S(1000), using the data from the fluorescence and surface detectors of the Pierre Auger Observatory. The test consists of fitting the measured two-dimensional (S(1000), Xmax) distributions using templates for simulated air showers produced with hadronic interaction models epos-lhc, qgsjet-ii-04, sibyll 2.3d and leaving the scales of predicted Xmax and the signals from hadronic component at ground as free-fit parameters. The method relies on the assumption that the mass composition remains …
Near-Collapse Of The Geomagnetic Field May Have Contributed To Atmospheric Oxygenation And Animal Radiation In The Ediacaran Period, Wentao Huang, John A. Tarduno, Tinghong Zhou, Mauricio Ibañez-Mejia, Laércio Dal Olmo-Barbosa, Edinei Koester, Eric G. Blackman, Aleksey V. Smirnov, Gabriel Ahrendt, Rory D. Cottrell, Kenneth P. Kodama, Richard K. Bono, David G. Sibeck, Yong Xiang Li, Francis Nimmo, Shuhai Xiao, Michael K. Watkeys
Near-Collapse Of The Geomagnetic Field May Have Contributed To Atmospheric Oxygenation And Animal Radiation In The Ediacaran Period, Wentao Huang, John A. Tarduno, Tinghong Zhou, Mauricio Ibañez-Mejia, Laércio Dal Olmo-Barbosa, Edinei Koester, Eric G. Blackman, Aleksey V. Smirnov, Gabriel Ahrendt, Rory D. Cottrell, Kenneth P. Kodama, Richard K. Bono, David G. Sibeck, Yong Xiang Li, Francis Nimmo, Shuhai Xiao, Michael K. Watkeys
Michigan Tech Publications
Earth’s magnetic field was in a highly unusual state when macroscopic animals of the Ediacara Fauna diversified and thrived. Any connection between these events is tantalizing but unclear. Here, we present single crystal paleointensity data from 2054 and 591 Ma pyroxenites and gabbros that define a dramatic intensity decline, from a strong Proterozoic field like that of today, to an Ediacaran value 30 times weaker. The latter is the weakest time-averaged value known to date and together with other robust paleointensity estimates indicate that Ediacaran ultra-low field strengths lasted for at least 26 million years. This interval of ultra-weak magnetic …
Exploring The Coronal Magnetic Field With Galactic Cosmic Rays: The Sun Shadow Observed By Hawc, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, R. Babu, Et Al.
Exploring The Coronal Magnetic Field With Galactic Cosmic Rays: The Sun Shadow Observed By Hawc, R. Alfaro, C. Alvarez, J. C. Arteaga-Velázquez, K. P. Arunbabu, D. Avila Rojas, R. Babu, Et Al.
Michigan Tech Publications
Galactic cosmic rays (GCRs) are charged particles that reach the heliosphere almost isotropically in a wide energy range. In the inner heliosphere, the GCR flux is modulated by solar activity so that only energetic GCRs reach the lower layers of the solar atmosphere. In this work, we propose that high-energy GCRs can be used to explore the solar magnetic fields at low coronal altitudes. We used GCR data collected by the High-Altitude Water Cherenkov observatory to construct maps of GCR flux coming from the Sun’s sky direction and studied the observed GCR deficit, known as Sun shadow (SS), over a …
A Jwst Survey Of The Supernova Remnant Cassiopeia A, Dan Milisavljevic, Tea Temim, Ilse De Looze, Danielle Dickinson, J. Martin Laming, Robert Fesen, John C. Raymond, Richard G. Arendt, Jacco Vink, Bettina Posselt, George G. Pavlov, Ori D. Fox, Ethan Pinarski, Bhagya Subrayan, Judy Schmidt, William P. Blair, Armin Rest, Daniel Patnaude, Bon Chul Koo, Jeonghee Rho, Salvatore Orlando, Hans Thomas Janka, Moira Andrews, Michael J. Barlow, Adam Burrows, Roger Chevalier, Geoffrey Clayton, Claes Fransson, Christopher Fryer, Haley L. Gomez, Florian Kirchschlager
A Jwst Survey Of The Supernova Remnant Cassiopeia A, Dan Milisavljevic, Tea Temim, Ilse De Looze, Danielle Dickinson, J. Martin Laming, Robert Fesen, John C. Raymond, Richard G. Arendt, Jacco Vink, Bettina Posselt, George G. Pavlov, Ori D. Fox, Ethan Pinarski, Bhagya Subrayan, Judy Schmidt, William P. Blair, Armin Rest, Daniel Patnaude, Bon Chul Koo, Jeonghee Rho, Salvatore Orlando, Hans Thomas Janka, Moira Andrews, Michael J. Barlow, Adam Burrows, Roger Chevalier, Geoffrey Clayton, Claes Fransson, Christopher Fryer, Haley L. Gomez, Florian Kirchschlager
Michigan Tech Publications
We present initial results from a James Webb Space Telescope (JWST) survey of the youngest Galactic core-collapse supernova remnant, Cassiopeia A (Cas A), made up of NIRCam and MIRI imaging mosaics that map emission from the main shell, interior, and surrounding circumstellar/interstellar material (CSM/ISM). We also present four exploratory positions of MIRI Medium Resolution Spectrograph integral field unit spectroscopy that sample ejecta, CSM, and associated dust from representative shocked and unshocked regions. Surprising discoveries include (1) a weblike network of unshocked ejecta filaments resolved to ∼0.01 pc scales exhibiting an overall morphology consistent with turbulent mixing of cool, low-entropy matter …
Machine Learning Techniques For Intermediate Mass Gap Lepton Partner Searches At The Large Hadron Collider, Bhaskar Dutta, Tathagata Ghosh, Alyssa Horne, Jason Kumar, Sean Palmer, Pearl Sandick, Marcus Snedeker, Patrick Stengel, Joel W. Walker
Machine Learning Techniques For Intermediate Mass Gap Lepton Partner Searches At The Large Hadron Collider, Bhaskar Dutta, Tathagata Ghosh, Alyssa Horne, Jason Kumar, Sean Palmer, Pearl Sandick, Marcus Snedeker, Patrick Stengel, Joel W. Walker
Michigan Tech Publications
We consider machine learning techniques associated with the application of a boosted decision tree (BDT) to searches at the Large Hadron Collider (LHC) for pair-produced lepton partners which decay to leptons and invisible particles. This scenario can arise in the minimal supersymmetric Standard Model (MSSM), but can be realized in many other extensions of the Standard Model (SM). We focus on the case of intermediate mass splitting (∼30 GeV) between the dark matter (DM) and the scalar. For these mass splittings, the LHC has made little improvement over LEP due to large electroweak backgrounds. We find that the use of …
Constraints On Metastable Superheavy Dark Matter Coupled To Sterile Neutrinos With The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, K. Nguyen, D. Nitz, Et Al.
Constraints On Metastable Superheavy Dark Matter Coupled To Sterile Neutrinos With The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, K. Nguyen, D. Nitz, Et Al.
Michigan Tech Publications
Dark matter particles could be superheavy, provided their lifetime is much longer than the age of the Universe. Using the sensitivity of the Pierre Auger Observatory to ultrahigh energy neutrinos and photons, we constrain a specific extension of the Standard Model of particle physics that meets the lifetime requirement for a superheavy particle by coupling it to a sector of ultralight sterile neutrinos. Our results show that, for a typical dark coupling constant of 0.1, the mixing angle θm between active and sterile neutrinos must satisfy, roughly, θm≲1.5×10-6(MX/109 GeV)-2 for a mass MX of the dark-matter particle between 108 GeV …
Estimating Polarization Purity With Noise, Alex Kostinski, Dan Kestner, Jothiram Vivekanandan
Estimating Polarization Purity With Noise, Alex Kostinski, Dan Kestner, Jothiram Vivekanandan
Michigan Tech Publications
We formulate a problem of estimating and monitoring mismatch (unwanted departure from orthogonality) of two ostensibly orthogonal polarization channels in a fully polarimetric general device such as a polarimetric weather radar. A statistical approach is proposed by using thermal noise or, more generally, a 'polarimetric noise' class of sources. The suitable noise class of distributions is shown to be rooted in the complex multivariate Gaussian probability density function (pdf), the latter possessing a uniform pdf on the Poincare sphere (PS), with a probability measure given by a fractional surface area. To that end, we develop a parameter to estimate polarization …