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Articles 31 - 60 of 492
Full-Text Articles in Physics
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 …
Enhancing Turbulent Mixing And Microphysical Uniformity In A Tall Convection-Cloud Chamber Through Idealized Heterogeneity Of Boundaries, Lois Thomas, Fan Yang, Aaron Wang, Mikhail Ovchinnikov, Kyle Pressel, Raymond Shaw
Enhancing Turbulent Mixing And Microphysical Uniformity In A Tall Convection-Cloud Chamber Through Idealized Heterogeneity Of Boundaries, Lois Thomas, Fan Yang, Aaron Wang, Mikhail Ovchinnikov, Kyle Pressel, Raymond Shaw
Michigan Tech Publications
A large convection cloud chamber has been proposed for exploring aerosol–cloud–drizzle interactions under well‐controlled turbulent conditions. Recent theoretical and numerical studies suggest that ac on vection cloud chamber with two heated and two cooled sidewalls can significantly enhance the liquid water content and thus benefit drizzle initiation. However, a chamber with such a sidewall configuration develops stable stratification and extremely weak turbulence therein. In this study, we conduct large‐eddy simulations of a tall convection chamber with five different sidewall configurations consisting of alternating warm and cold patches. For each configuration, the total surface area of warm patches equals that of …
Reliable Detection Of Sf6breakdown Byproducts Using 2d Non-Hexagonal Carbon Allotrope Nanosheets, Pedro Elias Priori Spalenza, Fábio Arthur Leão De Souza, Debora C.M. Rodrigues, Rodrigo G. Amorim, Cesar E.P. Villegas, Wanderlã L. Scopel, Ravindra Pandey
Reliable Detection Of Sf6breakdown Byproducts Using 2d Non-Hexagonal Carbon Allotrope Nanosheets, Pedro Elias Priori Spalenza, Fábio Arthur Leão De Souza, Debora C.M. Rodrigues, Rodrigo G. Amorim, Cesar E.P. Villegas, Wanderlã L. Scopel, Ravindra Pandey
Michigan Tech Publications
Sulfur hexafluoride (SF6), widely used as an insulating gas in the power industry, decomposes during long-term operation into byproducts such as H2S, SO2, SO2F2, and SOF2. Reliable detection of these compounds is essential, since their type and concentration provide diagnostic signatures of faults in gas-insulated switchgear. We employ density functional theory combined with nonequilibrium Green’s function calculations to evaluate pristine two-dimensional carbon allotropes with nonhexagonal rings, namely Graphene+, T-graphene, and Biphenylene, as potential field-effect nanosensors. To characterize the surfaces’ atomic structures, we simulated scanning tunneling microscopy images for filled states. Each surface exhibits a distinct brightness pattern that allows its …
Investigating Characteristic Droplet Size Distributions In Large Eddy Simulations Of Stratocumulus Clouds, Nithin Allwayin, Daniel J. Miller, Kamal Kant Chandrakar, Michael L. Larsen, Raymond A. Shaw
Investigating Characteristic Droplet Size Distributions In Large Eddy Simulations Of Stratocumulus Clouds, Nithin Allwayin, Daniel J. Miller, Kamal Kant Chandrakar, Michael L. Larsen, Raymond A. Shaw
Michigan Tech Publications
Cloud processes relevant to radiative and precipitation properties depend on the shape of the cloud droplet size distribution. Recent holographic observations revealed that cloud droplet populations do not have the same size distribution shapes throughout but form regions of characteristic distributions with similar microphysical properties. We investigate the existence and properties of these characteristic distributions within Large-Eddy Simulations of stratocumulus clouds using Lagrangian and bin microphysics schemes. Distribution types are identified, revealing localized characteristic distributions that vary on the scale of the largest convective cell for simulations with bin microphysics. The results from the Lagrangian microphysics scheme hint at similar …
Hawc Performance Enhanced By Machine Learning In Gamma-Hadron Separation, R. Alfaro, C. Alvarez, A. Andrés, E. Anita-Rangel, M. Araya, J. C. Arteaga-Velázquez, N. Ghosh, P. Hüntemeyer, K. Leavitt, M. Najafi, Et. Al
Hawc Performance Enhanced By Machine Learning In Gamma-Hadron Separation, R. Alfaro, C. Alvarez, A. Andrés, E. Anita-Rangel, M. Araya, J. C. Arteaga-Velázquez, N. Ghosh, P. Hüntemeyer, K. Leavitt, M. Najafi, Et. Al
Michigan Tech Publications
Improving gamma-hadron separation is one of the most effective ways to enhance the performance of ground-based gamma-ray observatories. With more than a decade of continuous operation, the High-Altitude Water Cherenkov (HAWC) Observatory has contributed significantly to high-energy astrophysics. To further leverage its rich data set, we introduce a machine learning approach for gamma-hadron separation. A multilayer perceptron shows the best performance, surpassing traditional and other machine learning-based methods. This approach shows a notable improvement in the detector’s sensitivity, supported by results from both simulated and real HAWC data. In particular, it achieves a 19% increase in significance for the Crab …
Study Of The Ic 443 Region With The Hawc Observatory, R. Alfaro, C. Alvarez, M. Araya, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, Et. Al
Study Of The Ic 443 Region With The Hawc Observatory, R. Alfaro, C. Alvarez, M. Araya, J. C. Arteaga-Velázquez, D. Avila Rojas, H. A. Ayala Solares, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, Et. Al
Michigan Tech Publications
Supernova remnants are one potential source class considered a PeVatron (i.e., capable of accelerating cosmic rays above PeV energies). The shock fronts produced after the explosion of the supernova are ideal regions for particle acceleration. IC 443 is a supernova remnant that has been studied extensively at different wavelengths. Using 2966 days of gamma-ray data from the High Altitude Water Cherenkov (HAWC) observatory, we study the emission of IC 443 with the objective of finding signatures of cosmic-ray acceleration at the PeV scale. Using a maximum likelihood method, we find a point source located at (α=94.°42, δ=22.°35) that we associate …
Hawc, Veritas, Fermi-Lat, And Xmm-Newton Follow-Up Observations Of The Unidentified Ultra-High-Energy Gamma-Ray Source Lhaaso J2108+5157, C. B. Adams, P. Bangale, W. Benbow, J. H. Buckley, Y. Chen, J. L. Christiansen, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, X. Wang, Et. Al
Hawc, Veritas, Fermi-Lat, And Xmm-Newton Follow-Up Observations Of The Unidentified Ultra-High-Energy Gamma-Ray Source Lhaaso J2108+5157, C. B. Adams, P. Bangale, W. Benbow, J. H. Buckley, Y. Chen, J. L. Christiansen, S. Groetsch, P. Hüntemeyer, M. Najafi, R. Turner, X. Wang, Et. Al
Michigan Tech Publications
We report observations of the ultra-high-energy gamma-ray source LHAASO J2108+5157, utilizing VERITAS, HAWC, Fermi-LAT, and XMM-Newton. VERITAS has collected ∼40 hr of data that we used to set ULs to the emission above 200 GeV. The HAWC data, collected over ∼2400 days, reveal emission between 3 and 146 TeV, with a significance of 7.5σ, favoring an extended source model. The best-fit spectrum measured by HAWC is characterized by a simple power law with a spectral index of 2.45 ± 0.11stat. Fermi-LAT analysis finds a point source with a very soft spectrum in the LHAASO J2108+5157 region, consistent with the 4FGL-DR3 …
Engineered Biochar-Attapulgite Clay Composite: A Novel Slow-Release Phosphorus Fertilizer, Harleen Kaur, Gurwinder Singh, Marjana Yeasmin, Kavitha Ramadass, Puspamitra Panigrahi, Alan Larson, Ranjit Pati, Dane Lamb, Bo Zheng, Ehsan Tavakkoli, Lukas Van Zwieten, Ajayan Vinu
Engineered Biochar-Attapulgite Clay Composite: A Novel Slow-Release Phosphorus Fertilizer, Harleen Kaur, Gurwinder Singh, Marjana Yeasmin, Kavitha Ramadass, Puspamitra Panigrahi, Alan Larson, Ranjit Pati, Dane Lamb, Bo Zheng, Ehsan Tavakkoli, Lukas Van Zwieten, Ajayan Vinu
Michigan Tech Publications
Sustainable agricultural practices are in high demand, and the development of innovative materials for slow nutrient release holds utmost importance. Phosphorus (P) stratification limits plant P availability in no-till farming systems. To address this, a nano composite-based P fertilizer to release nutrients in the root zone following surface soil application is constructed. The nanocomposite fertilizers (BAP-SRFs) were formed by a combination of different amounts of biochar (BC), attapulgite clay (ATP) and KH2PO4, followed by a high-temperature treatment (500 °C). XANES analysis revealed the enrichment of the surface with carbon (C), oxygen (O) and P-containing functional groups, and the bond formation …
Long-Range Quantum Entanglement In Dielectric Mu-Near-Zero Metamaterials, Olivia Mello, Larissa Vertchenko, Seth Nelson, Adrien Debacq, Durdu Guney, Eric Mazur, Michaël Lobet
Long-Range Quantum Entanglement In Dielectric Mu-Near-Zero Metamaterials, Olivia Mello, Larissa Vertchenko, Seth Nelson, Adrien Debacq, Durdu Guney, Eric Mazur, Michaël Lobet
Michigan Tech Publications
Entanglement is paramount in quantum information processing. Many quantum systems suffer from spatial decoherence in distances over a wavelength and cannot be sustained over short time periods due to dissipation. However, long range solutions are required for the development of quantum information processing on chip. Photonic reservoirs mediating the interactions between qubits and their environment are suggested. Recent research takes advantage of extended wavelength inside near-zero refractive index media to solve the long-range problem along with less sensitivity on the position of quantum emitters. However, those recent proposals use plasmonic epsilon near-zero waveguides that are intrinsically lossy. Here, we propose …
The Cosmoverse White Paper: Addressing Observational Tensions In Cosmology With Systematics And Fundamental Physics, Eleonora Di Valentino, Jackson Levi Said, Adam Riess, Agnieszka Pollo, Vivian Poulin, Adrià Gómez-Valent, Elena Giusarma, Et Al.
The Cosmoverse White Paper: Addressing Observational Tensions In Cosmology With Systematics And Fundamental Physics, Eleonora Di Valentino, Jackson Levi Said, Adam Riess, Agnieszka Pollo, Vivian Poulin, Adrià Gómez-Valent, Elena Giusarma, Et Al.
Michigan Tech Publications
The standard model of cosmology has provided a good phenomenological description of a wide range of observations both at astrophysical and cosmological scales for several decades. This concordance model is constructed by a universal cosmological constant and supported by a matter sector described by the standard model of particle physics and a cold dark matter contribution, as well as very early-time inflationary physics, and underpinned by gravitation through general relativity. There have always been open questions about the soundness of the foundations of the standard model. However, recent years have shown that there may also be questions from the observational …
The Scintillator Surface Detector 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.
The Scintillator Surface Detector 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
Data collected so far by the Pierre Auger Observatory have enabled major advances in ultrahigh energy cosmic ray physics and demonstrated that improved determination of masses of primary cosmic-ray particles, preferably on an event-by-event basis, is necessary for understanding their origin and nature. Improvement in primary mass measurements was the main motivation for the upgrade of the Pierre Auger Observatory, called AugerPrime. As part of this upgrade, scintillator detectors are added to the existing water-Cherenkov surface detector stations. By making use of the differences in detector response to the electromagnetic particles and muons between scintillator and water-Cherenkov detectors, the electromagnetic …
A Model Intercomparison Study Of Aerosol-Cloud-Turbulence Interactions In A Cloud Chamber: 1. Model Results, Sisi Chen, Steven K. Krueger, Piotr Dziekan, Kotaro Enokido, Theodore Macmillan, David Richter, Silvio Schmalfuß, Shin Ichiro Shima, Fan Yang, Jesse C. Anderson, Will Cantrell, Dennis Niedermeier, Raymond Shaw, Frank Stratmann
A Model Intercomparison Study Of Aerosol-Cloud-Turbulence Interactions In A Cloud Chamber: 1. Model Results, Sisi Chen, Steven K. Krueger, Piotr Dziekan, Kotaro Enokido, Theodore Macmillan, David Richter, Silvio Schmalfuß, Shin Ichiro Shima, Fan Yang, Jesse C. Anderson, Will Cantrell, Dennis Niedermeier, Raymond Shaw, Frank Stratmann
Michigan Tech Publications
This study presents the first model intercomparison of aerosol-cloud-turbulence interactions in a controlled cloudy Rayleigh-Bénard Convection chamber environment, utilizing the Pi Chamber at Michigan Technological University. We analyzed simulated cloud chamber-averaged statistics of microphysics and thermodynamics in a warm-phase, cloudy environment under steady-state conditions at varying aerosol injection rates. Simulation results from seven distinct models (DNS, LES, and a 1D turbulence model) were compared. Our findings demonstrate that while all models qualitatively capture observed trends in droplet number concentration, mean radius, and droplet size distributions at both high and low aerosol injection rates, significant quantitative differences were observed. Notably, droplet …
Data Supporting The Paper "Enhancing Turbulent Mixing And Microphysical Uniformity In A Tall Convection-Cloud Chamber Through Idealized Heterogeneity Of Boundaries", Lois Thomas, Fan Yang, Aaron Wang, Mikhail Ovchinnikov, Kyle G. Pressel, Raymond Shaw
Data Supporting The Paper "Enhancing Turbulent Mixing And Microphysical Uniformity In A Tall Convection-Cloud Chamber Through Idealized Heterogeneity Of Boundaries", Lois Thomas, Fan Yang, Aaron Wang, Mikhail Ovchinnikov, Kyle G. Pressel, Raymond Shaw
Michigan Tech Research Data
A large convection cloud chamber has been proposed for exploring aerosol–cloud–drizzle interactions under well-controlled turbulent conditions. Recent theoretical and numerical studies suggest that a convection cloud chamber with two heated and two cooled sidewalls can significantly enhance the liquid water content and thus benefit drizzle initiation. However, a chamber with such a sidewall configuration develops stable stratification and extremely weak turbulence therein. In this study, we conduct large-eddy simulations of a tall convection chamber with five different sidewall configurations consisting of alternating warm and cold patches. For each configuration, the total surface area of warm patches equals that of cold …
Scaler Rates From The Pierre Auger Observatory: A New Proxy Of Solar Activity, S. Mancuso, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, B. Fick, K. Nguyen, D. Nitz, Et Al.
Scaler Rates From The Pierre Auger Observatory: A New Proxy Of Solar Activity, S. Mancuso, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, B. Fick, K. Nguyen, D. Nitz, Et Al.
Michigan Tech Publications
The modulation of low-energy galactic cosmic rays reflects interplanetary magnetic field variations and can provide useful information on solar activity. An array of ground-surface detectors can reveal the secondary particles, which originate from the interaction of cosmic rays with the atmosphere. In this work, we present an investigation of the low-threshold rate (scaler) time series recorded in 16 yr of operation by the Pierre Auger Observatory surface detectors in Malargüe, Argentina. Through an advanced spectral analysis, we detected highly statistically significant variations in the time series with periods ranging from the decadal to the daily scale. We investigate their origin, …
Investigation Of Isobaric Mixing As A Mechanism For Boundary-Layer Cloud Formation, Jaemin Yeom, Nithin Allwayin, Virendra P. Ghate, Katia Lamer, Fan Mei, Raymond A. Shaw
Investigation Of Isobaric Mixing As A Mechanism For Boundary-Layer Cloud Formation, Jaemin Yeom, Nithin Allwayin, Virendra P. Ghate, Katia Lamer, Fan Mei, Raymond A. Shaw
Michigan Tech Publications
This study investigates the potential role of isobaric mixing in the formation of marine boundary layer clouds. Cloud formation theory emphasizes uplift and adiabatic cooling, but recent observations support the existence of small clouds forming at various altitudes, even below the lifting condensation level. Isobaric mixing of air with different thermodynamic properties can generate localized supersaturation. A Gaussian mixing model is employed to simulate this process, considering the correlation between temperature and water vapor. Cloud droplet size distributions from aircraft measurements show a persistent and prominent mode of small droplets at 9 (Formula presented.) m, and the size of this …
Hydrogen Storage In Multilayer Ti3c2tx Mxene, Yi Zhi Chu, Kah Chun Lau
Hydrogen Storage In Multilayer Ti3c2tx Mxene, Yi Zhi Chu, Kah Chun Lau
Michigan Tech Publications
In this work, we systematically investigated the hydrogen storage properties of multilayer Ti3C2Tx MXene using density functional theory (DFT) coupled with the quantum-thermodynamic model to include the thermodynamic effect on hydrogen adsorption and storage behavior over a wide range of applied pressure and temperature. In addition to the surface-adsorbed hydrogen, we show that the interlayer spacing is a plausible storage route that could contribute to an additional hydrogen storage capacity. Due to hydrogen-bond bounded multilayer Ti3C2Tx, the insertion, diffusion, and adsorption of hydrogen molecules into the interlayer spacing of the multilayer structure require sufficient external pressure to overcome the energy …
The Distribution Of Ultrahigh-Energy Cosmic Rays Along The Supergalactic Plane Measured At The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, K. Nguyen, D. Nitz, A. Puyleart, Et. Al
The Distribution Of Ultrahigh-Energy Cosmic Rays Along The Supergalactic Plane Measured At The Pierre Auger Observatory, A. Abdul Halim, P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, K. Nguyen, D. Nitz, A. Puyleart, Et. Al
Michigan Tech Publications
Ultrahigh-energy cosmic rays are known to be mainly of extragalactic origin, and their propagation is limited by energy losses, so their arrival directions are expected to correlate with the large-scale structure of the local Universe. In this work, we investigate the possible presence of intermediate-scale excesses in the flux of the most energetic cosmic rays from the direction of the supergalactic plane region using events with energies above 20 EeV recorded with the surface detector array of the Pierre Auger Observatory up to 2022 December 31, with a total exposure of 135,000 km2 sr yr. The strongest indication for an …
Search For A Diffuse Flux Of Photons With Energies Above Tens Of Pev At The Pierre Auger Observatory, A. Abdul Halim, P. P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, K. Nguyen, D. Nitz, Et Al.
Search For A Diffuse Flux Of Photons With Energies Above Tens Of Pev At The Pierre Auger Observatory, A. Abdul Halim, P. P. Abreu, M. Aglietta, I. Allekotte, K. Almeida Cheminant, A. Almela, B. Fick, K. Nguyen, D. Nitz, Et Al.
Michigan Tech Publications
Diffuse photons of energy above 0.1 PeV, produced through the interactions between cosmic rays and either interstellar matter or background radiation fields, are powerful tracers of the distribution of cosmic rays in the Galaxy. Furthermore, the measurement of a diffuse photon flux would be an important probe to test models of super-heavy dark matter decaying into gamma-rays. In this work, we search for a diffuse photon flux in the energy range between 50 PeV and 200 PeV using data from the Pierre Auger Observatory. For the first time, we combine the air-shower measurements from a 2 km2 surface array consisting …
An Intercomparison Of Wall Fluxes In A Turbulent Thermal Convection Chamber: Direct Numerical Simulations And Wall-Modeled Large-Eddy Simulations Enhanced By Machine Learning, Aaron Wang, Silvio Schmalfuß, Kamal Kant Chandrakar, Hadi Zanganeh Kia, Fan Yang, Mikhail Ovchinnikov, Raymond A. Shaw, Yunsoo Choi
An Intercomparison Of Wall Fluxes In A Turbulent Thermal Convection Chamber: Direct Numerical Simulations And Wall-Modeled Large-Eddy Simulations Enhanced By Machine Learning, Aaron Wang, Silvio Schmalfuß, Kamal Kant Chandrakar, Hadi Zanganeh Kia, Fan Yang, Mikhail Ovchinnikov, Raymond A. Shaw, Yunsoo Choi
Michigan Tech Publications
Thermal convection in a closed chamber is driven by a warm bottom, a cold top, and side walls at various temperatures. Although wall fluxes are the source of convection energy, accurately modeling these fluxes (i.e., the wall model) is challenging. In large-eddy simulations (LESs), many wall models are traditionally derived from the canonical boundary layer, which may be unsuitable for thermal convection bounded by both horizontal and vertical walls. This study conducts a model intercomparison of dry convection in a cubic-meter chamber using three direct numerical simulations (DNSs) and four LESs with different wall models. The LESs employ traditional wall …
Boron Nitride Nanosheets, Quantum Dots, And Dots: Synthesis, Properties, And Biomedical Applications, Raksha Dubey, Matthew Cowles, Zohreh Salimi, Xiuling Liu, Rodney Oakley, Nazmiye B. Yapici, Join Uddin, Dongyan Zhang, Yoke Khin Yap
Boron Nitride Nanosheets, Quantum Dots, And Dots: Synthesis, Properties, And Biomedical Applications, Raksha Dubey, Matthew Cowles, Zohreh Salimi, Xiuling Liu, Rodney Oakley, Nazmiye B. Yapici, Join Uddin, Dongyan Zhang, Yoke Khin Yap
Michigan Tech Publications
This review examines three aspects of hexagonal boron nitride (h-BN) nanomaterials: properties, synthesis methods, and biomedical applications. We focus the scope of review on three types of h-BN nanostructures: boron nitride nanosheets (BNNSs, few-layered h-BN, larger than ∼100 nm in lateral dimensions), boron nitride quantum dots (BN QDs, smaller than ∼10 nm in all dimensions, with inherent excitation-dependent fluorescence), and boron nitride dots (BN dots, smaller than ∼10 nm in all dimensions, wide bandgap without noise fluorescence). The synthesis methods of BNNSs, BN QDs, and BN dots are summarized in top-down and bottom-up approaches. Future synthesis research should focus on …
Understanding The Growth Mechanism Of Thiol-Conjugated Au25 Cluster, Chunhui Liu, Haiying He, Ravindra Pandey, Shashi P. Karna
Understanding The Growth Mechanism Of Thiol-Conjugated Au25 Cluster, Chunhui Liu, Haiying He, Ravindra Pandey, Shashi P. Karna
Michigan Tech Publications
The synthesis of ligand-conjugated gold nanoclusters has attracted significant attention due to its ability to achieve precise control over cluster size selectivity. Among these, Au25(SR)18-, where R represents an alkyl group, is one of the earliest being synthesized with a very high yield, although its growth mechanism is yet to be fully understood. Using density functional theory, we present the results of a theoretical investigation on the growth process of Au25(SR)18-, beginning from Au13(SR)12-. Our findings indicate that the sulfur atoms in the core structure of Au13 …
Microphysics Regimes Due To Haze–Cloud Interactions: Cloud Oscillation And Cloud Collapse, Fan Yang, Hamed F. Sadi, Raymond Shaw, Fabian Hoffmann, Pei Hou, Aaron Wang, Mikhail Ovchinnikov
Microphysics Regimes Due To Haze–Cloud Interactions: Cloud Oscillation And Cloud Collapse, Fan Yang, Hamed F. Sadi, Raymond Shaw, Fabian Hoffmann, Pei Hou, Aaron Wang, Mikhail Ovchinnikov
Michigan Tech Publications
It is known that aqueous haze particles can be activated into cloud droplets in a supersaturated environment. However, haze–cloud interactions have not been fully explored, partly because haze particles are not represented in most cloud-resolving models. Here, we conduct a series of large-eddy simulations (LESs) of a cloud in a convection chamber using a haze-capable Eulerian-based bin microphysics scheme to explore haze–cloud interactions over a wide range of aerosol injection rates. Results show that the cloud is in a slow microphysics regime at low aerosol injection rates, where the cloud responds slowly to an environmental change and droplet deactivation is …
Search For The Anomalous Events Detected By Anita Using 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.
Search For The Anomalous Events Detected By Anita Using 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
A dedicated search for upward-going air showers at zenith angles exceeding 110° and energies E>0.1 EeV has been performed using the Fluorescence Detector of the Pierre Auger Observatory. The search is motivated by two "anomalous"radio pulses observed by the ANITA flights I and III that appear inconsistent with the standard model of particle physics. Using simulations of both regular cosmic-ray showers and upward-going events, a selection procedure has been defined to separate potential upward-going candidate events and the corresponding exposure has been calculated in the energy range [0.1-33] EeV. One event has been found in the search period between …
Coupled Lake-Atmosphere-Land Physics Uncertainties In A Great Lakes Regional Climate Model, William J. Pringle, Chenfu Huang, Pengfei Xue, Jiali Wang, Khachik Sargsyan, Miraj Kayastha, Et. Al.
Coupled Lake-Atmosphere-Land Physics Uncertainties In A Great Lakes Regional Climate Model, William J. Pringle, Chenfu Huang, Pengfei Xue, Jiali Wang, Khachik Sargsyan, Miraj Kayastha, Et. Al.
Michigan Tech Publications
This study develops a surrogate-based method to assess the uncertainty within a convective permitting integrated modeling system of the Great Lakes region, arising from interacting physics parameterizations across the lake, atmosphere, and land surface. Perturbed physics ensembles of the model during the 2018 summer are used to train a neural network surrogate model to predict lake surface temperature (LST) and near-surface air temperature (T2m). Average physics uncertainties are determined to be 1.5°C for LST and T2m over land, and 1.9°C for T2m over lake, but these have significant spatiotemporal variations. We find that atmospheric physics parameterizations alone are the dominant …
The Pierre Auger Observatory Open Data, M. Zavrtanik, D. Zavrtanik, E. Zas, O. Zapparrata, A. Yushkov, B. Yue, B. Fick, K. Nguyen, D. Nitz, Et Al.
The Pierre Auger Observatory Open Data, M. Zavrtanik, D. Zavrtanik, E. Zas, O. Zapparrata, A. Yushkov, B. Yue, B. Fick, K. Nguyen, D. Nitz, Et Al.
Michigan Tech Publications
The Pierre Auger Collaboration has embraced the concept of open access to their research data since its foundation, with the aim of giving access to the widest possible community. A gradual process of release began as early as 2007 when 1% of the cosmic-ray data was made public, along with 100% of the space-weather information. In February 2021, a portal was released containing 10% of cosmic-ray data collected by the Pierre Auger Observatory from 2004 to 2018, during the first phase of operation of the Observatory. The Open Data Portal includes detailed documentation about the detection and reconstruction procedures, analysis …
Cryogenic Hybrid Magnonic Circuits Based On Spalled Yig Thin Films, Jing Xu, Connor Horn, Yu Jiang, Amin Pishehvar, Xinhao Li, Daniel Rosenmann, Xu Han, Miguel Levy, Supratik Guha, Xufeng Zhang
Cryogenic Hybrid Magnonic Circuits Based On Spalled Yig Thin Films, Jing Xu, Connor Horn, Yu Jiang, Amin Pishehvar, Xinhao Li, Daniel Rosenmann, Xu Han, Miguel Levy, Supratik Guha, Xufeng Zhang
Michigan Tech Publications
Yttrium iron garnet (YIG) magnonics has garnered significant research interest because of the unique properties of magnons (quasiparticles of collective spin excitation) for signal processing. In particular, hybrid systems based on YIG magnonics show great promise for quantum information science due to their broad frequency tunability and strong compatibility with other platforms. However, their broad applications have been severely constrained by substantial microwave loss in the gadolinium gallium garnet (GGG) substrate at cryogenic temperatures. In this study, we demonstrate that YIG thin films can be spalled from YIG/GGG samples. Our approach is validated by measuring hybrid devices comprising superconducting resonators …
Detection Of Extended X-Ray Emission Around The Pevatron Microquasar V4641 Sgr With Xrism, Hiromasa Suzuki, Naomi Tsuji, Yoshiaki Kanemaru, Megumi Shidatsu, Laura Olivera-Nieto, Samar Safi-Harb, Shigeo S. Kimura, Eduardo De La Fuente, Sabrina Casanova, Kaya Mori, Xiaojie Wang, Sei Kato, Dai Tateishi, Hideki Uchiyama, Takaaki Tanaka, Hiroyuki Uchida, Shun Inoue, Dezhi Huang, Marianne Lemoine-Goumard, Daiki Miura, Shoji Ogawa, Shogo B. Kobayashi, Chris Done, Maxime Parra, Maria Díaz Trigo, Teo Muñoz-Darias, Montserrat Armas Padilla, Ryota Tomaru, Yoshihiro Ueda
Detection Of Extended X-Ray Emission Around The Pevatron Microquasar V4641 Sgr With Xrism, Hiromasa Suzuki, Naomi Tsuji, Yoshiaki Kanemaru, Megumi Shidatsu, Laura Olivera-Nieto, Samar Safi-Harb, Shigeo S. Kimura, Eduardo De La Fuente, Sabrina Casanova, Kaya Mori, Xiaojie Wang, Sei Kato, Dai Tateishi, Hideki Uchiyama, Takaaki Tanaka, Hiroyuki Uchida, Shun Inoue, Dezhi Huang, Marianne Lemoine-Goumard, Daiki Miura, Shoji Ogawa, Shogo B. Kobayashi, Chris Done, Maxime Parra, Maria Díaz Trigo, Teo Muñoz-Darias, Montserrat Armas Padilla, Ryota Tomaru, Yoshihiro Ueda
Michigan Tech Publications
A recent report on the detection of very-high-energy gamma rays from V4641 Sagittarii (V4641 Sgr) up to ≈0.8 PeV has made it the second confirmed “PeVatron” microquasar. Here we report on the observation of V4641 Sgr with X-Ray Imaging and Spectroscopy Mission (XRISM) in 2024 September. Thanks to the large field of view and low background, the CCD imager Xtend successfully detected for the first time X-ray extended emission around V4641 Sgr with a significance of ≳4.5σ and >10σ based on our imaging and spectral analysis, respectively. The spatial extent is estimated to have a radius of 7′ ± 3′ …