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Articles 1 - 30 of 325
Full-Text Articles in Physics
Pentagonal Pdte2 Monolayer For Sustainable Solar-Driven Hydrogen Production, Narender Kumar, Shambhu Bhandari, Dario Alfè, Ravindra Pandey, Nacir Tit
Pentagonal Pdte2 Monolayer For Sustainable Solar-Driven Hydrogen Production, Narender Kumar, Shambhu Bhandari, Dario Alfè, Ravindra Pandey, Nacir Tit
Michigan Tech Publications
This investigation demonstrates that the pentagonal PdTe2 (penta-PdTe2) monolayer is a highly tunable two-dimensional (2D) photocatalyst, characterized by the bandgap of 1.87 eV and high hole mobility. Using density functional theory calculations with the HSE06 functional, we show that tensile strain engineering (particularly at +2% and +3%) is essential for enabling spontaneous water splitting. At these strain values, the valence-band maximum and conduction-band maximum straddle the water redox potentials (H+/H2 and O2/H2O) under both acidic (pH = 0) and neutral (pH = 7) conditions. The monolayer's low hole effective mass facilitates rapid charge extraction, mitigating recombination and driving the oxygen …
Long-Term Monitoring Of The Optical Performance Of The Primary Mirrors At The Coihueco And Loma Amarilla Sites Of The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, M. Ahmed, I. Allekotte, K. Almeida Cheminant, B. Fick, K. Nguyen, D. Nitz, Et Al.
Long-Term Monitoring Of The Optical Performance Of The Primary Mirrors At The Coihueco And Loma Amarilla Sites Of The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, M. Ahmed, I. Allekotte, K. Almeida Cheminant, B. Fick, K. Nguyen, D. Nitz, Et Al.
Michigan Tech Publications
This paper presents the results of an optical performance monitoring campaign for the primary mirrors installed in fluorescence telescopes at the Coihueco and Loma Amarilla sites at the Pierre Auger Observatory in Argentina. Since the end of 2003, this effort has developed into a unique long-term dataset that addresses the performance of the primary mirrors. We have focused on the scattering characteristics and specular reflectance of mirror segments, as well as their evolution over several years of operation. Despite being housed in climate-controlled buildings, dust accumulation, impurities, and natural aging — such as oxidation or other chemical or physical degradation …
Using Galex Uv Excess To Search For Metal-Poor Halo Stars, Chase L. Smith, Maxwell Moe, Megan Frank, Raven Cilley, Javier Fregoso, Alexander Gleason, Grace Nelson, Et Al.
Using Galex Uv Excess To Search For Metal-Poor Halo Stars, Chase L. Smith, Maxwell Moe, Megan Frank, Raven Cilley, Javier Fregoso, Alexander Gleason, Grace Nelson, Et Al.
Michigan Tech Publications
Metal-poor solar-type stars display a significant reduction in metal-line blanketing at short wavelengths, leading to an excess of near-ultraviolet (NUV) flux compared to their metal-rich counterparts. We utilize Galaxy Evolution Explorer Satellite (GALEX) NUV and Gaia DR3 photometry along with ground-based spectroscopy to establish a correlation between NUV excess and [Fe/H]. We construct a sample of 492 solar-type (F5-G9) halo stars with NUV excess and measured metallicities. We perform our own observations with the KOSMOS spectrograph at Apache Point Observatory’s 3.5 m telescope to measure the abundances of 13 halo stars, 11 of which did not have previous metallicity measurements. …
Detectability Of Polarized Γ-Ray Emission From Blazar Flares With Cosi, Garrett A. Latiolais, Jorge Otero-Santos, Michela Negro, Lea Marcotulli, Mohammad Ali Boroumand, Savitri Gallego, Tiffany Lewis, Et Al.
Detectability Of Polarized Γ-Ray Emission From Blazar Flares With Cosi, Garrett A. Latiolais, Jorge Otero-Santos, Michela Negro, Lea Marcotulli, Mohammad Ali Boroumand, Savitri Gallego, Tiffany Lewis, Et Al.
Michigan Tech Publications
We investigate the detectability of polarized γ-ray emission from blazar flares with the Compton Spectrometer and Imager (COSI). Using 17 yr of Fermi Large Area Telescope observations, we analyze light curves for 1413 blazars and identify a maximum of 787 sources with flaring episodes through Bayesian block analysis. For each flare, we estimate the minimum detectable polarization (MDP99%) in the COSI energy band (0.2–5 MeV) using instrument response functions under a range of spectral assumptions and background conditions. Under baseline background levels (1 count s−1) and assuming that blazar flare statistics in the MeV band are comparable to …
Constraints On Axion-Like Particles From Ultra-High-Energy Observations Of M87 With The Hawc Observatory, R. Alfaro, C. Alvarez, A. Andrés, E. Anita-Rangel, M. Araya, J. C. Arteaga-Velázquez, N. Ghosh, M. Najafi, Et Al.
Constraints On Axion-Like Particles From Ultra-High-Energy Observations Of M87 With The Hawc Observatory, R. Alfaro, C. Alvarez, A. Andrés, E. Anita-Rangel, M. Araya, J. C. Arteaga-Velázquez, N. Ghosh, M. Najafi, Et Al.
Michigan Tech Publications
In this work, we perform an indirect search for axion-like particles (ALPs) through their hypothesized mixing with photons in the presence of magnetic fields. ALPs are a well-motivated dark-matter candidate class, and the photon-ALP conversion mechanism provides a unique channel to constrain their mass and coupling constant using very-high-energy gamma-ray observations. The photon-ALP mixing could alter the observed gamma-ray spectrum from extragalactic sources by effectively reducing the apparent attenuation due to extragalactic-background-light absorption. We analyze 7.5 years of data from the High Altitude Water Cherenkov (HAWC) Observatory, targeting the nearby radio galaxy M87. This source is located within the Virgo …
Spectro-Polarimetric Observations Of Tev Sources (Spots): First Results, Joleen Barnard, B. Van Soelen, I. P. Van Der Westhuizen, M. Böttcher, A. Martin-Carrillo, H. M. Schutte, S. Van Der Merwe, M. Zacharias
Spectro-Polarimetric Observations Of Tev Sources (Spots): First Results, Joleen Barnard, B. Van Soelen, I. P. Van Der Westhuizen, M. Böttcher, A. Martin-Carrillo, H. M. Schutte, S. Van Der Merwe, M. Zacharias
Michigan Tech Publications
Blazars are jetted active galactic nuclei, with the jet aligned along the observer’s line of sight. Their spectral energy distributions are dominated by non-thermal emission, with an underlying thermal component at optical/ultraviolet wavelengths. However, the underlying jet magnetic field structure and particle acceleration mechanisms requirements for the non-thermal emission are still under debate. Polarization measurements can provide critical insights, and we investigate the optical polarization properties of TeV-emitting blazars using long-term optical monitoring. We present results from the first 21 months of the Spectro-Polarimetric Observations of TeV Sources campaign, using the Southern African Large Telescope, of 14 blazars. Overall, observations …
Theoretical Study Of Electronic Properties Of Functionalized Monolayers: Cu, Ag, Au, And Pt Atomic Wires On Graphene, H-Bn Monolayer, Silicene, And Phosphorene, Mythreyee T. Aasuri, Mukesh K. Choudhary, Narender Kumar, Ravindra Pandey
Theoretical Study Of Electronic Properties Of Functionalized Monolayers: Cu, Ag, Au, And Pt Atomic Wires On Graphene, H-Bn Monolayer, Silicene, And Phosphorene, Mythreyee T. Aasuri, Mukesh K. Choudhary, Narender Kumar, Ravindra Pandey
Michigan Tech Publications
The structural and electronic properties of graphene, h-BN monolayer, silicene, and phosphorene monolayers functionalized with Cu, Ag, Au, and Pt atomic wires were investigated using van der Waals─corrected density functional theory. These atomic wires form stable, functionalized monolayers that exhibit physisorption on planar monolayers and chemisorption on nonplanar ones. This results in either linear or bent configurations of the atomic wires, depending on the interface strength, leading to distinct electronic states. A weaker interface induces metal-induced gap states near the Fermi level, whereas a stronger interface results in covalently hybridized states farther from the Fermi level. Analysis of the electron …
Breathing Kagome Lattice-Based Nb3i8 Monolayer: Theoretical Insights Into Enhanced Hydrogen Evolution Catalysis, Narender Kumar, Radha Somaiya, Ravindra Pandey, Nacir Tit
Breathing Kagome Lattice-Based Nb3i8 Monolayer: Theoretical Insights Into Enhanced Hydrogen Evolution Catalysis, Narender Kumar, Radha Somaiya, Ravindra Pandey, Nacir Tit
Michigan Tech Publications
Photocatalytic water splitting is a promising strategy for clean energy production, but its efficiency is restricted by poor light absorption, charge recombination, and slow reaction kinetics in photocatalytic materials. To address these challenges, a breathing Kagome lattice-based Nb3I8 monolayer is considered in the present study. Its photocatalytic performance is assessed via descriptors including the effective d-band center, spin-dependent carrier mobility, Gibbs free energy, and exchange-current density. The results based on density functional theory predict that the Nb3I8 monolayer is a type II magnetic semiconductor, with spin-up and spin-down bandgap energies of 1.06 and 1.77 eV, respectively. The application of biaxial …
Quantum Dot Solar Cells: Background, Progress, And Perspective, Kumar Neupane, Jeff Kabel, Join Uddin, Raksha Dubey, Rojina Ojha, Dongyan Zhang, Yoke Khin Yap
Quantum Dot Solar Cells: Background, Progress, And Perspective, Kumar Neupane, Jeff Kabel, Join Uddin, Raksha Dubey, Rojina Ojha, Dongyan Zhang, Yoke Khin Yap
Michigan Tech Publications
The discovery of quantum dots (QDs) earned a Nobel Prize and has led to widespread applications in research and technology. In this review, we focus on the use of QDs in solid-state solar cells (QDSCs). We begin with an overview of the basic principles of SCs. Then, we discuss how device architecture has developed over recent decades, setting the stage for the final section on fourth-generation solar cells (Perspective section). We also highlight progress in material development, starting with lead- and cadmium-based QDs and progressing to more recent carbon- and perovskite-based QDs. Additionally, we review materials used for electron-transport layers …
A Model Intercomparison Study To Investigate Mixing Characteristics In Non-Precipitating Stratocumulus Clouds, Fan Yang, Kyoung Ock Choi, Kamal Kant Chandrakar, Fabian Hoffmann, Pei Hou, Steve Krueger, Chunsong Lu, Mikhail Ovchinnikov, Yangze Ren, Shin Ichiro Shima, Peng Wu, Chongzhi Yin, Zeen Zhu, Seong Soo Yum
A Model Intercomparison Study To Investigate Mixing Characteristics In Non-Precipitating Stratocumulus Clouds, Fan Yang, Kyoung Ock Choi, Kamal Kant Chandrakar, Fabian Hoffmann, Pei Hou, Steve Krueger, Chunsong Lu, Mikhail Ovchinnikov, Yangze Ren, Shin Ichiro Shima, Peng Wu, Chongzhi Yin, Zeen Zhu, Seong Soo Yum
Michigan Tech Publications
Recent aircraft observations of marine stratocumulus clouds consistently showed that cloud microphysical relationships vary with altitude, indicating inhomogeneous mixing characteristics near cloud top and homogeneous mixing characteristics in mid-levels of clouds. Here, we conduct model intercomparison of an idealized, non-precipitating stratocumulus cloud to evaluate model consistency and examine whether simulations can reproduce the observed mixing characteristics. The results show that eleven large-eddy simulations with various dynamics and microphysics schemes show good agreement on the thermodynamical, microphysical, and dynamical properties of the stratocumulus-topped boundary layer in a steady state. The inter-model spread in steady-state liquid water path is significantly reduced compared …
Evaluating The Collision-Coalescence Process In Idealized Cloud Convection Using Large-Eddy Simulations With Lagrangian Microphysics, Yangze Ren, Kamal Kant Chandrakar, Fan Yang, Raymond Shaw
Evaluating The Collision-Coalescence Process In Idealized Cloud Convection Using Large-Eddy Simulations With Lagrangian Microphysics, Yangze Ren, Kamal Kant Chandrakar, Fan Yang, Raymond Shaw
Michigan Tech Publications
Drizzle initiation through the collision and coalescence of cloud droplets plays a crucial role in warm cloud precipitation. Recent theoretical studies suggest that the influence of collisional growth on the droplet size distribution can be quantified by a non‐dimensional drizzle number (Dz). Here, large‐eddy simulations with Lagrangian microphysics are employed to evaluate the theory by simulating a tall convection‐cloud chamber under various conditions. Results show that the smaller the Dz, the larger the impact of collisions on the right tail of the droplet size distribution, consistent with the theory. The simulations confirm that the collision rate can be estimated from …
Combined Dark Matter Search Towards Dwarf Spheroidal Galaxies With Fermi-Lat, Hawc, H.E.S.S., Magic, And Veritas, S. Abdollahi, L. Baldini, R. Bellazzini, B. Berenji, E. Bissaldi, R. Bonino, X. Wang, R. Turner, P. Hüntemeyer, Et Al.
Combined Dark Matter Search Towards Dwarf Spheroidal Galaxies With Fermi-Lat, Hawc, H.E.S.S., Magic, And Veritas, S. Abdollahi, L. Baldini, R. Bellazzini, B. Berenji, E. Bissaldi, R. Bonino, X. Wang, R. Turner, P. Hüntemeyer, Et Al.
Michigan Tech Publications
Dwarf spheroidal galaxies (dSphs) are excellent targets for indirect dark matter (DM) searches using gamma-ray telescopes because they are thought to have high DM content and a low astrophysical background. The sensitivity of these searches is improved by combining the observations of dSphs made by different gamma-ray telescopes. We present the results of a combined search by the most sensitive currently operating gamma-ray telescopes, namely: the satellite-borne Fermi-LAT telescope; the ground-based imaging atmospheric Cherenkov telescope arrays H.E.S.S., MAGIC, and VERITAS; and the HAWC water Cherenkov detector. Individual datasets were analyzed using a common statistical approach. Results were subsequently combined via …
Search For Ultra-High-Energy Neutrons From Galactic Sources 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
Search For Ultra-High-Energy Neutrons From Galactic Sources 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
Michigan Tech Publications
Deflections in the propagation of charged ultra-high-energy cosmic rays (UHECRs) caused by magnetic fields make the identification of their sources challenging. On the other hand, the arrival directions at Earth of neutrons point directly to their origin. The emission of UHECRs from a source is expected to be accompanied by the production of neutrons in its vicinity through interactions with ambient matter and radiation. Since free neutrons travel a mean distance d kpc−1 = 9.2 (E EeV−1) before decaying, a neutron flux in the EeV range could be detected on Earth from sources of UHECRs in our Galaxy. Using …
Interactions Between Air Pollution And Weather/Climate From Urban To Global Scales, Meng Gao, Xin Huang, Yucong Miao, Mengmeng Li, Claudio Mazzoleni
Interactions Between Air Pollution And Weather/Climate From Urban To Global Scales, Meng Gao, Xin Huang, Yucong Miao, Mengmeng Li, Claudio Mazzoleni
Michigan Tech Publications
Air pollution and meteorology are intricately linked. Weather modulates the formation, transport, and removal of pollutants, while aerosols and trace gases modify radiation balance, cloud microphysics, boundary-layer structure, and other factors. These two-way interactions span scales from urban to global and have important consequences. The papers collected in this special issue of Meteorological Applications examine how interactions between weather and pollution at various scales affect visibility, pollutant transport, crop yields, and other outcomes, collectively highlighting the crucial role of the interplay between air pollution and meteorology.
Non-Stokes Deposition Velocities Observed Under Rayleigh–Bénard Turbulence, Kristin Swartz-Schult, Andrew Grace, Andrew Bragg, Jesse C. Anderson, Will Cantrell, Robert Grosz, Hamed F. Sadi, Raymond Shaw, Swafuva Varappillikudy Sulaiman, Et Al.
Non-Stokes Deposition Velocities Observed Under Rayleigh–Bénard Turbulence, Kristin Swartz-Schult, Andrew Grace, Andrew Bragg, Jesse C. Anderson, Will Cantrell, Robert Grosz, Hamed F. Sadi, Raymond Shaw, Swafuva Varappillikudy Sulaiman, Et Al.
Michigan Tech Publications
The settling and deposition behavior of small particles significantly impacts many environmental and industrial processes. Although particle settling dynamics within turbulent environments have been extensively studied through theory and simulation, more experimental investigation is needed to test the idealized results against real-world turbulent flows. In this work, we infer the settling velocity of particles in Rayleigh–Bénard (RB) turbulence through the measurement of declines in particle concentration due to deposition within a (Formula presented.) convection chamber. Oil droplets from (Formula presented.) to (Formula presented.) and glass beads from (Formula presented.) to (Formula presented.) were used as the particle material, yielding Kolmogorov-based …
Νgan: A Deep Learning Emulator For Cosmic Web Simulations With Massive Neutrinos, Neerav Kaushal, Elena Giusarma, Mauricio Reyes
Νgan: A Deep Learning Emulator For Cosmic Web Simulations With Massive Neutrinos, Neerav Kaushal, Elena Giusarma, Mauricio Reyes
Michigan Tech Publications
Understanding the impact of neutrino masses on the evolution of the Universe is a central goal of modern cosmology. Due to their large free-streaming lengths, neutrinos significantly affect structure formation at nonlinear scales, requiring accurate theoretical predictions to fully exploit current and future galaxy surveys. However, generating such predictions through large ensembles of cosmological simulations is computationally expensive. In this work, we introduce a deep learning-based generative adversarial network, νGAN, to emulate the Universe across a range of neutrino masses from 0.0 to 1.2 eV. The generated 2D cosmic web maps are statistically independent, show no correlations with the training …
A Theoretical Investigation Of The Linear And Nonlinear Optical Responses Of Scandium- And Yttrium-Doped (Sub-Nm) Ag And Au Clusters, Munish Sharma, Mukesh Jakhar, Ravindra Pandey, Shashi P. Karna
A Theoretical Investigation Of The Linear And Nonlinear Optical Responses Of Scandium- And Yttrium-Doped (Sub-Nm) Ag And Au Clusters, Munish Sharma, Mukesh Jakhar, Ravindra Pandey, Shashi P. Karna
Michigan Tech Publications
We investigate the linear and nonlinear optical properties of (sub-nm) Ag6 and Au6 clusters doped with Sc and Y using time-dependent density functional theory. Both parent clusters have D3h ground-state geometries but exhibit noticeably different electronic structures; scalar-relativistic corrections in Au6 induce significant s-d hybridization, resulting in larger HOMO-LUMO gaps and reduced one-photon absorption (OPA) cross-sections compared to Ag6. Two-photon absorption (TPA) peaks in the UV region show resonance enhancement via coupling with OPA-active states, with Ag6 having larger cross-sections than Au6. Doping with Sc and Y modifies the optical responses by breaking configurational symmetry and lifting HOMO degeneracies. ScAg5 …
Least Squares As Random Walks: The General Case Of Arbitrary Spacing, Daniel Kestner, Alexander Kostinski
Least Squares As Random Walks: The General Case Of Arbitrary Spacing, Daniel Kestner, Alexander Kostinski
Michigan Tech Publications
Recently, we introduced the notion of a random walk based on a discrete sequence of data samples ( data walk ) and discovered a surprising link between ordinary least squares (OLS) fits to evenly sampled data and random walks. Here we generalize earlier results by showing that the slope of a linear fit to data which annuls the net area under a residual data walk equals that found by OLS for irregularly spaced data sequence. We also discover a deep connection with the orthogonality principle of estimation theory, leading to interpretation of suitably defined scalar products of data vectors as …
Natural Protective Mechanisms Of Cucumis Callosus Leaves In Escherichia Species-Induced Urinary Tract Infection: An Integrated In Silico And In Vivo Study, Meenal Sahu, Tripti Paliwal, Radhika Joshi, Arya Kuhu Vishwapriya, Namita Misra, Smita Jain, Gautam Singhvi, Gulshan Kumar, Devesh U. Kapoor, Dipjyoti Chakraborty, Swapnil Sharma
Natural Protective Mechanisms Of Cucumis Callosus Leaves In Escherichia Species-Induced Urinary Tract Infection: An Integrated In Silico And In Vivo Study, Meenal Sahu, Tripti Paliwal, Radhika Joshi, Arya Kuhu Vishwapriya, Namita Misra, Smita Jain, Gautam Singhvi, Gulshan Kumar, Devesh U. Kapoor, Dipjyoti Chakraborty, Swapnil Sharma
Michigan Tech Publications
Leaves of Cucumis callosus, traditionally employed in Ayurvedic medicine for the treatment of urinary disorders, were investigated in depth for their therapeutic potential against bacterially induced urinary tract infection (UTI) for the first time. The present work is the first to explore the antibacterial activity of C. callosus leaf fractions with an integrative in silico, in vitro, and in vivo approach. Through bioassay-guided fractionation, the chloroform fraction (F1) was identified as the most active, exhibiting potent activity against Uropathogenic Escherichia spp. species. Liquid chromatography–mass spectrometry (LC-MS) analysis of F1 revealed the presence of bioactive compounds, including stigmasterol, 1,2,3,4-tetrahydroisoquinoline, lactose, hydroxy(mesityl)acetic …
High Thermoelectric Power Conversion Efficiency Of An Earth-Abundant Janus Silicon Oxy-Sulfide Monolayer: A First-Principles Study, Zakariae Darhi, Mounaim Bencheikh, Ravindra Pandey, Larbi El Farh
High Thermoelectric Power Conversion Efficiency Of An Earth-Abundant Janus Silicon Oxy-Sulfide Monolayer: A First-Principles Study, Zakariae Darhi, Mounaim Bencheikh, Ravindra Pandey, Larbi El Farh
Michigan Tech Publications
The tunable properties of Janus monolayers, along with advances in their synthesis, make these low-symmetry materials excellent candidates for thermoelectric power generation. In this study, we systematically investigate the electronic and thermal properties of the Janus silicon oxy-sulfide monolayer. The results based on density functional theory reveal that the monolayer is stable. It exhibits a tunable direct band gap and strong covalent bonding. Its ultralow lattice thermal conductivity (< 0.38 W mK−1 at 300 K) is attributed to the broken phonon selection rule for phonon–phonon scattering and a high level of anharmonicity, as reflected in the large Grüneisen parameter. Furthermore, the inclusion …
Haze Processing Of Atmospheric Particles During Wintertime In The Indo-Gangetic Plains, Susan Mathai, Amna Ijaz, Tania Gautam, Zezhen Cheng, Nurun Nahar Lata, Harsh Bhotika, David Tseng, Rosalie K. Chu, Lynn Mazzoleni, Claudio Mazzoleni, Swarup China
Haze Processing Of Atmospheric Particles During Wintertime In The Indo-Gangetic Plains, Susan Mathai, Amna Ijaz, Tania Gautam, Zezhen Cheng, Nurun Nahar Lata, Harsh Bhotika, David Tseng, Rosalie K. Chu, Lynn Mazzoleni, Claudio Mazzoleni, Swarup China
Michigan Tech Publications
The impacts of haze on visibility, air quality, and climate are not well quantified due to a lack of understanding of the evolution of the mixing state and phase state of atmospheric particles during haze processing. The variability of the mixing state of atmospheric particles contributes significantly to uncertainties associated with the estimated aerosol radiative forcing. We collected particle samples in January 2018 from the highly polluted Indo-Gangetic plain during hazy conditions to study haze-processed particles. Single particle analysis using multi-modal micro-spectroscopy techniques revealed an abundance (40–70% by number) of potassium-rich sulfate particles from biomass-burning influenced smoke. Tilted view imaging …
Statistics Of Glinting Clouds Observed By Dscovr And Geostationary Satellites, Tamás Várnai, Alexander Marshak, Alexander Kostinski
Statistics Of Glinting Clouds Observed By Dscovr And Geostationary Satellites, Tamás Várnai, Alexander Marshak, Alexander Kostinski
Michigan Tech Publications
This study examines how frequently the specular reflection of sunlight—that is, sun glint—reveals the presence of ice crystals that maintain a steady horizontal orientation. The study analyzes data from the Earth Polychromatic Imaging Camera (EPIC) onboard the Deep Space Climate Observatory (DSCOVR) spacecraft and from collocated images taken by geostationary satellites. The analysis of spatio-temporal variations in glint frequency over vegetated land surfaces reveals that (a) year-to-year variations are modest with no clear trends; (b) glints typically occur 7%–8% more frequently than previously estimated; (c) glints are most frequently observed during the May-August period, and over Asia. The results also …
Large Aerosol Particles Favor Haze Conditions Through Limitations On Water Budget And Activation Kinetics, Hamed F. Sadi, Ernie Lewis, Kadja Flore Gali, Fan Yang, Jesse Anderson, Suryadev Pratap Singh, Jae Min Yeom, Will Cantrell, Raymond Shaw
Large Aerosol Particles Favor Haze Conditions Through Limitations On Water Budget And Activation Kinetics, Hamed F. Sadi, Ernie Lewis, Kadja Flore Gali, Fan Yang, Jesse Anderson, Suryadev Pratap Singh, Jae Min Yeom, Will Cantrell, Raymond Shaw
Michigan Tech Publications
Experiments in the Pi Convection‐Cloud Chamber conducted by systematically changing the diameter of injected dry aerosol particles while holding the temperature difference constant demonstrate that dry diameter strongly influences the onset of haze‐dominated conditions. Two factors contribute: the system becomes water‐limited, resulting in reduction of supersaturation by growing aerosol particles to the activation diameter; and the activation process becomes kinetically limited. Dry aerosol diameter exerts a strong influence on activation time, with a power‐law exponent of 9/2. Kinetically limited activation occurs when the ratio of the activation and droplet residence times is greater than unity. The findings demonstrate that a …
Predicting Oil Contamination In Water Using Machine Learning On Microbial Compositions, Tong Gao, Isaac Bigcraft, Stephen Techtmann, Issei Nakamura
Predicting Oil Contamination In Water Using Machine Learning On Microbial Compositions, Tong Gao, Isaac Bigcraft, Stephen Techtmann, Issei Nakamura
Michigan Tech Publications
We present a compact and generative machine-learning framework that predicts oil contamination based on microbial community compositions from experimental samples. Our method combines dimensionality reduction with data augmentation and generative modeling to address high-dimensional, non-linear, and sparse microbial data. To reduce the 503-dimensional bacterial composition dataset, we compared three dimensionality reduction techniques: feature importance from random forest, principal component analysis (PCA), and t-distributed stochastic neighbor embedding (t-SNE). Feature importance outperformed PCA and t-SNE, improving predictive performance and identifying microbial species most strongly correlated with oil contamination. To mitigate data scarcity, we augmented the training data using an augmented data neural …
Design And Modeling Of A Thin Water Falling-Film For Convection-Cloud Chambers, Grant T. Schlaff, Jesse Anderson, Brandon Kieranen, Constantine M. Megaridis, Raymond Shaw
Design And Modeling Of A Thin Water Falling-Film For Convection-Cloud Chambers, Grant T. Schlaff, Jesse Anderson, Brandon Kieranen, Constantine M. Megaridis, Raymond Shaw
Michigan Tech Publications
Convection–cloud chambers offer a controlled environment to study aerosol-cloud interactions. Ensuring sustained supersaturation in these chambers requires a reliable and efficient water sourcing mechanism. Maintaining saturated boundary conditions on side-walls is important in chambers with large vertical dimensions (up to 10m) aimed at achieving collisional growth of cloud droplets. This study introduces the design, modeling, and measurement of a falling-film system capable of maintaining a stable, continuously replenished water film for continuous evaporation. A distributor is tested, ensuring uniform water coverage over a panel with a range of surface treatments. These surface treatments with micron to 100micron-scale roughness allow for …
Cloud-Top Entrainment Instability In Marine Stratocumulus Clouds: Observational Evidence From Collocated Microphysical, Turbulence, And Radiation Measurements, Inyeob La, Raymond Shaw, Holger Siebert, André Ehrlich, Jae Min Yeom, Seong Soo Yum
Cloud-Top Entrainment Instability In Marine Stratocumulus Clouds: Observational Evidence From Collocated Microphysical, Turbulence, And Radiation Measurements, Inyeob La, Raymond Shaw, Holger Siebert, André Ehrlich, Jae Min Yeom, Seong Soo Yum
Michigan Tech Publications
Marine stratocumulus clouds (MSC) strongly influence Earth's radiation budget, yet the mechanisms governing the descent of entrainment-affected (diluted) parcels, and the relative roles of cloud-top entrainment instability (CTEI) and longwave radiative cooling (RC), remain debated. Using helicopter-borne observations from the ACORES campaign that combine high-resolution in situ vertical profiling with co-located remote sensing, we examine vertical variations of microphysics, thermodynamics, and the entrainment interfacial layer (EIL). When CTEI conditions were strongly met, inhomogeneous mixing (IM) traits appeared near cloud top and transitioned to homogeneous mixing (HM) traits deeper in the cloud layer, accompanied by localized elevations of cloud base, signatures …
Long-Term Calibration And Validation Of Stability Of The Auger Engineering Radio Array Using The Diffuse Galactic Radio Emission, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, R. Aloisio, B. Fick, Et Al.
Long-Term Calibration And Validation Of Stability Of The Auger Engineering Radio Array Using The Diffuse Galactic Radio Emission, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, R. Aloisio, B. Fick, Et Al.
Michigan Tech Publications
The Auger Engineering Radio Array (AERA) measures radio emission from high-energy extensive air showers. Consisting of 153 autonomous radio-detector stations spread over 17 km^2, it detects radio waves in the frequency range of 30 to 80 MHz. Accurate characterization of the detector response is crucial for proper interpretation of the collected data. Previously, this was achieved through laboratory measurements of the analog chain and simulations and measurements of the antenna's directional response. In this paper, we perform an absolute calibration using the continuously monitored sidereal modulation of the diffuse Galactic radio emission. Calibration is done by comparing the average frequency …
High-Resolution Lidar Observations Of Sedimentation-Induced Size Sorting Of Droplets Near A Laboratory Cloud Top, Fan Yang, Yong Meng Sua, Zipei Zheng, Jesse Anderson, Hamed F. Sadi, Jae Min Yeom, Suryadev Pratap Singh, Pei Hou, Will Cantrell, Ernie Lewis, Alex Kostinski, Raymond Shaw
High-Resolution Lidar Observations Of Sedimentation-Induced Size Sorting Of Droplets Near A Laboratory Cloud Top, Fan Yang, Yong Meng Sua, Zipei Zheng, Jesse Anderson, Hamed F. Sadi, Jae Min Yeom, Suryadev Pratap Singh, Pei Hou, Will Cantrell, Ernie Lewis, Alex Kostinski, Raymond Shaw
Michigan Tech Publications
No abstract provided.
The First 10 Years Of The Hawc Gamma-Ray Observatory: Science Results, A. Albert, R. Alfaro, C. Alvarez, A. Andrés, E. Anita-Rangel, M. Araya, N. Ghosh, S. Groetsch, P. Huntemeyer, N. Kelley-Hoskins, K. Leavitt, T. Lewis, M. Najafi, R. Turner
The First 10 Years Of The Hawc Gamma-Ray Observatory: Science Results, A. Albert, R. Alfaro, C. Alvarez, A. Andrés, E. Anita-Rangel, M. Araya, N. Ghosh, S. Groetsch, P. Huntemeyer, N. Kelley-Hoskins, K. Leavitt, T. Lewis, M. Najafi, R. Turner
Michigan Tech Publications
The High-Altitude Water Cherenkov (HAWC) Observatory, located on the slopes of the Sierra Negra volcano in Mexico, began operations in March 2015. Over the past decade, HAWC has enabled the exploration of a broad range of topics in high-energy astrophysics and particle physics, resulting in more than 90 peer-reviewed publications. These studies have significantly advanced our understanding of several previously unexplored and poorly understood phenomena in the TeV energy regime. The present work provides an overview of the key scientific contributions of HAWC during its first ten years of operation.
Identification Of Novel Tat-I24-Related Peptides With Antiviral Activities, Hanna Harant, Siegfried Hofinger, Reingard Grabherr, Zsolt Ruzsics, Hartmut Hengel
Identification Of Novel Tat-I24-Related Peptides With Antiviral Activities, Hanna Harant, Siegfried Hofinger, Reingard Grabherr, Zsolt Ruzsics, Hartmut Hengel
Michigan Tech Publications
To identify novel peptides with potential antiviral activities, a database search was performed based on the primary sequence of the peptide I24 (CLAFYACFC), the effective part of the antiviral peptide TAT-I24 consisting of peptide I24 and the cell penetrating TAT-peptide (amino-acids 48–60, GRKKRRQRRRPPQ). A Protein BLAST search identified several sequences with high similarity to I24 in diverse proteins, some of which are known to be involved in the interaction with nucleic acids. Selected sequences and newly designed variants of I24 were synthesized as TAT fusion peptides and tested for antiviral activity in two well-established models: baculovirus transduction of HEK293 cells …