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Full-Text Articles in Physics
Is Contact Nucleation Caused By Pressure Perturbation?, Fan Yang, Will Cantrell, Alexander Kostinski, Raymond Shaw, Andrew M. Vogelmann
Is Contact Nucleation Caused By Pressure Perturbation?, Fan Yang, Will Cantrell, Alexander Kostinski, Raymond Shaw, Andrew M. Vogelmann
Michigan Tech Publications
The reason why ice nucleation is more efficient by contact nucleation than by immersion nucleation has been elusive for over half a century. Six proposed mechanisms are summarized in this study. Among them, the pressure perturbation hypothesis, which arose from recent experiments, can qualitatively explain nearly all existing results relevant to contact nucleation. To explore the plausibility of this hypothesis in a more quantitative fashion and to guide future investigations, this study assessed the magnitude of pressure perturbation needed to cause contact nucleation and the associated spatial scales. The pressure perturbations needed were estimated using measured contact nucleation efficiencies for …
Laboratory Study Of The Heterogeneous Ice Nucleation On Black-Carbon-Containing Aerosol, Leonid Nichman, Martin Wolf, Paul Davidovits, Timothy Onasch, Yue Zhang, Doug Worsnop, Janarjan Bhandari, Claudio Mazzoleni, Daniel Cziczo
Laboratory Study Of The Heterogeneous Ice Nucleation On Black-Carbon-Containing Aerosol, Leonid Nichman, Martin Wolf, Paul Davidovits, Timothy Onasch, Yue Zhang, Doug Worsnop, Janarjan Bhandari, Claudio Mazzoleni, Daniel Cziczo
Michigan Tech Publications
Soot and black carbon (BC) particles are generated in the incomplete combustion of fossil fuels, biomass, and biofuels. These airborne particles affect air quality, human health, aerosol–cloud interactions, precipitation formation, and climate. At present, the climate effects of BC particles are not well understood. Their role in cloud formation is obscured by their chemical and physical variability and by the internal mixing states of these particles with other compounds. Ice nucleation in field studies is often difficult to interpret. Nonetheless, most field studies seem to suggest that BC particles are not efficient ice-nucleating particles (INPs). On the other hand, laboratory …
Extensive Soot Compaction By Cloud Processing From Laboratory And Field Observations, Janarjan Bhandari, Swarup China, Kamal Kant Chandrakar, Greg Kinney, Will Cantrell, Raymond Shaw, Lynn Mazzoleni, Giulia Girotto, Noopur Sharma, Kyle Gorkowski, Stefania Gilardoni, Stefano Decesari, Maria Cristina Facchini, Nicola Zanca, Giulia Pavese, Francesco Esposito, Manvendra K Dubey, Allison C Aiken, Rajan K Chakrabarty, Hans Moosmüller, Timothy B Onasch, Rahul A Zaveri, Barbara V Scarnato, Paulo Fialho, Claudio Mazzoleni
Extensive Soot Compaction By Cloud Processing From Laboratory And Field Observations, Janarjan Bhandari, Swarup China, Kamal Kant Chandrakar, Greg Kinney, Will Cantrell, Raymond Shaw, Lynn Mazzoleni, Giulia Girotto, Noopur Sharma, Kyle Gorkowski, Stefania Gilardoni, Stefano Decesari, Maria Cristina Facchini, Nicola Zanca, Giulia Pavese, Francesco Esposito, Manvendra K Dubey, Allison C Aiken, Rajan K Chakrabarty, Hans Moosmüller, Timothy B Onasch, Rahul A Zaveri, Barbara V Scarnato, Paulo Fialho, Claudio Mazzoleni
Michigan Tech Publications
Soot particles form during combustion of carbonaceous materials and impact climate and air quality. When freshly emitted, they are typically fractal-like aggregates. After atmospheric aging, they can act as cloud condensation nuclei, and water condensation or evaporation restructure them to more compact aggregates, affecting their optical, aerodynamic, and surface properties. Here we survey the morphology of ambient soot particles from various locations and different environmental and aging conditions. We used electron microscopy and show extensive soot compaction after cloud processing. We further performed laboratory experiments to simulate atmospheric cloud processing under controlled conditions. We find that soot particles sampled after …
Astro2020 Apc White Paper: Elevating The Role Of Software As A Product Of The Research Enterprise, Arfon Smith, Dara Norman, Kelle Cruz, Vandana Desai, Eric Bellm, Robert J. Nemiroff, Et. Al.
Astro2020 Apc White Paper: Elevating The Role Of Software As A Product Of The Research Enterprise, Arfon Smith, Dara Norman, Kelle Cruz, Vandana Desai, Eric Bellm, Robert J. Nemiroff, Et. Al.
Michigan Tech Publications
Software is a critical part of modern research, and yet there are insufficient mechanisms in the scholarly ecosystem to acknowledge, cite, and measure the impact of research software. The majority of academic fields rely on a one-dimensional credit model whereby academic articles (and their associated citations) are the dominant factor in the success of a researcher's career. In the petabyte era of astronomical science, citing software and measuring its impact enables academia to retain and reward researchers that make significant software contributions. These highly skilled researchers must be retained to maximize the scientific return from petabyte-scale datasets. Evolving beyond the …
Searching For Dark Matter Sub-Structure With Hawc, A. U. Abeysekara, A. Albert, R. Alfaro, C. Alvarez, R. Arceo, J. C. Arteaga-Valazquez, Chad Brisbois, H. Fleischhack, Binita Hona, P. Huntemeyer, Et Al.
Searching For Dark Matter Sub-Structure With Hawc, A. U. Abeysekara, A. Albert, R. Alfaro, C. Alvarez, R. Arceo, J. C. Arteaga-Valazquez, Chad Brisbois, H. Fleischhack, Binita Hona, P. Huntemeyer, Et Al.
Michigan Tech Publications
Numerical simulations show that the dark matter halos surrounding galaxies are expected to contain many over-densities or sub-halos. The most massive of these sub-halos can be optically observed in the form of dwarf galaxies. However, most lower mass sub-halos are predicted to exist as dark dwarf galaxies: sub-halos like dwarf galaxies with no luminous counterpart. It may be possible to detect these unseen sub-halos from gamma-ray signals originating from dark matter annihilation. The High Altitude Water Cherenkov Observatory (HAWC) is a very high energy (500 GeV to >100 TeV) gamma ray detector with a wide field-of-view and near continuous duty …
Scaling Of An Atmospheric Model To Simulate Turbulence And Cloud Microphysics In The Pi Chamber, Subin Thomas, Mikhail Ovichinnikov, Fan Yang, Dennis Van Der Voort, Will Cantrell, Steven K. Krueger, Raymond Shaw
Scaling Of An Atmospheric Model To Simulate Turbulence And Cloud Microphysics In The Pi Chamber, Subin Thomas, Mikhail Ovichinnikov, Fan Yang, Dennis Van Der Voort, Will Cantrell, Steven K. Krueger, Raymond Shaw
Michigan Tech Publications
The Pi Cloud Chamber offers a unique opportunity to study aerosol-cloud microphysics interactions in a steady-state, turbulent environment. In this work, an atmospheric large-eddy simulation (LES) model with spectral bin microphysics is scaled down to simulate these interactions, allowing comparison with experimental results. A simple scalar flux budget model is developed and used to explore the effect of sidewalls on the bulk mixing temperature, water vapor mixing ratio, and supersaturation. The scaled simulation and the simple scalar flux budget model produce comparable bulk mixing scalar values. The LES dynamics results are compared with particle image velocimetry measurements of turbulent kinetic …
Turbulence-Induced Cloud Voids: Observation And Interpretation, Katarzyna Karpinska, Jonathan F. E. Bodenschatz, Szymon P. Malinowski, Jakub L. Nowak, Steffen Risius, Tina Schmeissner, Raymond Shaw, Holger Siebert, Hengdong Xi, Haitao Xu, Eberhard Bodenschatz
Turbulence-Induced Cloud Voids: Observation And Interpretation, Katarzyna Karpinska, Jonathan F. E. Bodenschatz, Szymon P. Malinowski, Jakub L. Nowak, Steffen Risius, Tina Schmeissner, Raymond Shaw, Holger Siebert, Hengdong Xi, Haitao Xu, Eberhard Bodenschatz
Michigan Tech Publications
The phenomenon of “cloud voids”, i.e., elongated volumes inside a cloud that are devoid of droplets, was observed with laser sheet photography in clouds at a mountain-top station. Two experimental cases, similar in turbulence conditions yet with diverse droplet size distributions and cloud void prevalence, are reported. A theoretical explanation is proposed based on the study of heavy inertial sedimenting particles inside a Burgers vortex. A general conclusion regarding void appearance is drawn from theoretical analysis. Numerical simulations of polydisperse droplet motion with realistic vortex parameters and Mie scattering visual effects accounted for can explain the presence of voids with …
The Magnetocaloric Effect & Performance Of Magnetocaloric Materials In A 1d Active Magnetic Regenerator Simulation, Daniel Nicholas Bayer
The Magnetocaloric Effect & Performance Of Magnetocaloric Materials In A 1d Active Magnetic Regenerator Simulation, Daniel Nicholas Bayer
Browse all Theses and Dissertations
Active magnetic regenerators (AMRs) operate according to the magnetothermal phenomenon known as the magnetocaloric effect (MCE), and are at the forefront of magnetic cooling technology. AMR simulations have been shown to be useful tools in predicting the performance of different magnetocaloric materials (MCMs) without the need to develop a physical prototype. In a search to determine the set of operational parameters which would maximize MCM performance, a 1D simulation of an AMR device has been developed in Matlab. Gadolinium, the most well-documented MCM, is used as a benchmark material to study the effects of varying certain operational parameters such as …
Introduction To The Second Special Issue On Biological Mentality, Kenneth Augustyn
Introduction To The Second Special Issue On Biological Mentality, Kenneth Augustyn
Michigan Tech Publications
No abstract provided.
Electron Spectrum Of The Dragonfly Pulsar Wind Nebula From X-Ray To Tev, Chad Brisbois, V. Joshi
Electron Spectrum Of The Dragonfly Pulsar Wind Nebula From X-Ray To Tev, Chad Brisbois, V. Joshi
Michigan Tech Publications
The Dragonfly nebula is a Vela-like Pulsar Wind Nebula (PWN) in the Cygnus region powered by the spin down of PSR J2021+3651. In X-rays, the inner nebula is a few arcseconds across, whereas at TeV energies VERITAS and HAWC has observed extended emission much larger than the extension in X-rays. The TeV gamma-ray source HAWC J2019+368 was originally discovered in 2007 by the Milagro Observatory and has been associated with this pulsar. Recent work has shown hints of energy dependent morphology for the source at TeV energies, supporting the interpretation of the gamma-ray emission being due to Inverse Compton scattering …
First Galactic Survey Of Energy-Dependent Diffusion By Hawc, Chad Brisbois, Hao Zhou
First Galactic Survey Of Energy-Dependent Diffusion By Hawc, Chad Brisbois, Hao Zhou
Michigan Tech Publications
HAWC’s wide field-of-view enables unbiased observations of much of the galaxy, allowing for analysis of many candidate sources in the HAWC dataset. Recent work has allowed HAWC to start investigating electron diffusion around pulsars at TeV energies. Surveying electron diffusion at TeV energies along the galactic plane is a unique capability of HAWC that allows us to examine the sources of electrons in our galaxy and constrain the energy dependence of the diffusion mech-anism. HAWC has already applied this model to the Geminga and Monogem pulsars. This work will expand the study to include multiple sources associated with pulsars in …
Testing The Limits Of Particle Acceleration In Cygnus Ob2 With Hawc, Binita Hona, H. Fleischhack, Petra Huentemeyer
Testing The Limits Of Particle Acceleration In Cygnus Ob2 With Hawc, Binita Hona, H. Fleischhack, Petra Huentemeyer
Michigan Tech Publications
Star forming regions (SFRs) have been postulated as possible sources of cosmic rays (CRs) in our galaxy. One example of a gamma-ray source associated with an SFR is the Fermi-LAT cocoon, an extended region of gamma-ray emission in the Cygnus X region and attributed to a possible superbubble with freshly accelerated CRs. Because the emission region is surrounded by ionization fronts, it has been named the Cygnus cocoon. CRs in the cocoon could have originated in the OB2 association and been accelerated at the interaction sites of stellar winds of massive O type stars. So far, there is no clear …
Studies Of The Time Structure Of Extended Air Showers For Direction Reconstruction With The Hawc Outrigger Array, Dezhi Huang
Studies Of The Time Structure Of Extended Air Showers For Direction Reconstruction With The Hawc Outrigger Array, Dezhi Huang
Michigan Tech Publications
The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a ground-based air shower array designed to detect Cherenkov light produced in water by secondary particles from atmospheric air showers. In order to improve the sensitivity at the highest energies, especially for the shower cores falling outside the main array, 345 smaller Water Cherenkov Detectors (WCDs) were installed around the main array, the outrigger array. This extension increased the instrumented area of HAWC by a factor of four. With the increased size of the array, and the ability to detect shower particles further away from the core, understanding of the time …
Physical Foundations Of Biological Mentality, Kenneth Augustyn
Physical Foundations Of Biological Mentality, Kenneth Augustyn
Michigan Tech Publications
Dualism struggles to connect two layers: the conscious mind and the physical workings of matter. It ignores a vast middle layer between the two, a layer that is beneath consciousness yet above known physical law. This middle layer is trans-robotic mentality, a means discovered by Nature to transcend robotic mentality. This middle layer evolved over billions of years before consciousness emerged from it, assuming more and more functions critical to survival as species evolved. Consciousness eventually emerged from trans-robotic mentality (not from robotic mentality), first intermittently then later more-or-less continuously. But there is no direct link between consciousness and matter. …