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2019

University of Nevada, Las Vegas

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Articles 1 - 30 of 155

Full-Text Articles in Physical Sciences and Mathematics

First-Principles Study Of High-Pressure Phase Stability And Superconductivity Of Bi4i4, Shiyu Deng, Xianqi Song, Quan Li, Yu Xie, Changfeng Chen, Yanming Ma Dec 2019

First-Principles Study Of High-Pressure Phase Stability And Superconductivity Of Bi4i4, Shiyu Deng, Xianqi Song, Quan Li, Yu Xie, Changfeng Chen, Yanming Ma

Physics & Astronomy Faculty Publications

Bismuth iodide Bi4I4 exhibits intricate crystal structures and topological insulating states that are highly susceptible to influence by environments, making its physical properties highly tunable by external conditions. In this work, we study the evolution of structural and electronic properties of Bi4I4 at high pressure using an advanced structure search method in conjunction with first-principles calculations. Our results indicate that the most stable ambient-pressure monoclinic α−Bi4I4 phase in C2/m symmetry transforms to a trigonal P31c structure (ɛ−Bi4I4) at 8.4 GPa, then to a tetragonal P4/mmm structure (ζ−Bi4I4) above 16.6 GPa. In contrast to ...


Subglacial Meltwater Supported Aerobic Marine Habitats During Snowball Earth, Maxwell A. Lechte, Malcolm W. Wallace, Ashleig Van Smeerdijk Hooda, Weiqiang Li, Ganqing Jiang, Galen P. Halverson, Dan Asael, Stephanie L. Mccoll, Noah J. Planavsky Dec 2019

Subglacial Meltwater Supported Aerobic Marine Habitats During Snowball Earth, Maxwell A. Lechte, Malcolm W. Wallace, Ashleig Van Smeerdijk Hooda, Weiqiang Li, Ganqing Jiang, Galen P. Halverson, Dan Asael, Stephanie L. Mccoll, Noah J. Planavsky

Geoscience Faculty Publications

The Earth’s most severe ice ages interrupted a crucial interval in eukaryotic evolution with widespread ice coverage during the Cryogenian Period (720 to 635 Ma). Aerobic eukaryotes must have survived the “Snowball Earth” glaciations, requiring the persistence of oxygenated marine habitats, yet evidence for these environments is lacking. We examine iron formations within globally distributed Cryogenian glacial successions to reconstruct the redox state of the synglacial oceans. Iron isotope ratios and cerium anomalies from a range of glaciomarine environments reveal pervasive anoxia in the ice-covered oceans but increasing oxidation with proximity to the ice shelf grounding line. We propose ...


Bringing Statistical Learning Machines Together For Hydro-Climatological Predictions - Case Study For Sacramento San Joaquin River Basin, California, Balbhadra Thakur, Ajay Kalra, Sajjad Ahmad, Kenneth W. Lamb, Venkat Lakshmi Dec 2019

Bringing Statistical Learning Machines Together For Hydro-Climatological Predictions - Case Study For Sacramento San Joaquin River Basin, California, Balbhadra Thakur, Ajay Kalra, Sajjad Ahmad, Kenneth W. Lamb, Venkat Lakshmi

Civil & Environmental Engineering and Construction Faculty Publications

Study region: Sacramento San Joaquin River Basin, California Study focus: The study forecasts the streamflow at a regional scale within SSJ river basin with largescale climate variables. The proposed approach eliminates the bias resulting from predefined indices at regional scale. The study was performed for eight unimpaired streamflow stations from 1962–2016. First, the Singular Valued Decomposition (SVD) teleconnections of the streamflow corresponding to 500 mbar geopotential height, sea surface temperature, 500 mbar specific humidity (SHUM500), and 500 mbar U-wind (U500) were obtained. Second, the skillful SVD teleconnections were screened non-parametrically. Finally, the screened teleconnections were used as the streamflow ...


Nanopatterned Silk Fibroin Films With High Transparency And High Haze For Optical Applications, Corey Malinowski, Fengjie He, Yihong Zhao, Ivan Chang, David W. Hatchett, Shengjie Zhai, Hui Zhao Dec 2019

Nanopatterned Silk Fibroin Films With High Transparency And High Haze For Optical Applications, Corey Malinowski, Fengjie He, Yihong Zhao, Ivan Chang, David W. Hatchett, Shengjie Zhai, Hui Zhao

Chemistry and Biochemistry Faculty Publications

Simultaneous high transparency and high haze are necessary for high-efficiency optical, photonic, and optoelectronic applications. However, a typical highly transparent film lacks high optical haze or vice versa. Here, we report a silk fibroin-based optical film that exhibits both ultrahigh optical transparency... (See article for full abstract).


Semitransparent Sb2s3 Thin Film Solar Cells By Ultrasonic Spray Pyrolysis For Use In Solar Windows, Jako S. Eensalu, Atanas Katerski, Erki Kärber, Lothar Weinhardt, Monika Blum, Clemens Heske, Wanli Yang, Ilona Oja Acik, Malle Krunks Dec 2019

Semitransparent Sb2s3 Thin Film Solar Cells By Ultrasonic Spray Pyrolysis For Use In Solar Windows, Jako S. Eensalu, Atanas Katerski, Erki Kärber, Lothar Weinhardt, Monika Blum, Clemens Heske, Wanli Yang, Ilona Oja Acik, Malle Krunks

Chemistry and Biochemistry Faculty Publications

The integration of photovoltaic (PV) solar energy in zero-energy buildings requires durable and efficient solar windows composed of lightweight and semitransparent thin film solar cells. Inorganic materials with a high optical absorption coefficient, such as Sb2S3 (>105 cm−1 at 450 nm), offer semitransparency, appreciable efficiency, and long-term durability at low cost. Oxide-free throughout the Sb2S3 layer thickness, as confirmed by combined studies of energy dispersive X-ray spectroscopy and synchrotron soft X-ray emission spectroscopy, semitransparent Sb2S3 thin films can be rapidly grown in air by the area-scalable ultrasonic spray pyrolysis method. Integrated into a ITO/TiO2/Sb2S3/P3HT/Au solar ...


A Unified Binary Neutron Star Merger Magnetar Model For The Chandra X-Ray Transients Cdf-S Xt1 And Xt2, Hui Sun, Ye Li, Bin-Bin Zhang, Bing Zhang, Franz E. Bauer, Yongquan Xue, Weimin Yuan Nov 2019

A Unified Binary Neutron Star Merger Magnetar Model For The Chandra X-Ray Transients Cdf-S Xt1 And Xt2, Hui Sun, Ye Li, Bin-Bin Zhang, Bing Zhang, Franz E. Bauer, Yongquan Xue, Weimin Yuan

Physics & Astronomy Faculty Publications

Two bright X-ray transients were reported from the Chandra Deep Field South (CDF-S) archival data, namely CDF-S XT1 and XT2. Whereas the nature of the former is not identified, the latter was suggested as an excellent candidate for a rapidly spinning magnetar born from a binary neutron star (BNS) merger. Here we propose a unified model to interpret both transients within the framework of the BNS merger magnetar model. According to our picture, CDF-S XT2 is observed from the "free zone" where the magnetar spindown powered X-ray emission escapes freely, whereas CDF-S XT1 originates from the "trapped zone" where the ...


3d-Printing And Machine Learning Control Of Soft Ionic Polymer-Metal Composite Actuators, James D. Carrico, Tucker Hermans, Kwang J. Kim, Kam K. Leang Nov 2019

3d-Printing And Machine Learning Control Of Soft Ionic Polymer-Metal Composite Actuators, James D. Carrico, Tucker Hermans, Kwang J. Kim, Kam K. Leang

Mechanical Engineering Faculty Publications

This paper presents a new manufacturing and control paradigm for developing soft ionic polymer-metal composite (IPMC) actuators for soft robotics applications. First, an additive manufacturing method that exploits the fused-filament (3D printing) process is described to overcome challenges with existing methods of creating custom-shaped IPMC actuators. By working with ionomeric precursor material, the 3D-printing process enables the creation of 3D monolithic IPMC devices where ultimately integrated sensors and actuators can be achieved. Second, Bayesian optimization is used as a learning-based control approach to help mitigate complex time-varying dynamic effects in 3D-printed actuators. This approach overcomes the challenges with existing methods ...


Gaseous, Pm2.5 Mass, And Speciated Emission Factors From Laboratory Chamber Peat Combustion, John G. Watson, Junji Cao, Lung-Wen Antony Chen, Qiyuan Wang, Jie Tian, Xiaoliang Wang, Steven Gronstal, Steven Sai Hang Ho, Adam C. Watts, Judith C. Chow Nov 2019

Gaseous, Pm2.5 Mass, And Speciated Emission Factors From Laboratory Chamber Peat Combustion, John G. Watson, Junji Cao, Lung-Wen Antony Chen, Qiyuan Wang, Jie Tian, Xiaoliang Wang, Steven Gronstal, Steven Sai Hang Ho, Adam C. Watts, Judith C. Chow

Public Health Faculty Publications

Peat fuels representing four biomes of boreal (western Russia and Siberia), temperate (northern Alaska, USA), subtropical (northern and southern Florida, USA), and tropical (Borneo, Malaysia) regions were burned in a laboratory chamber to determine gas and particle emission factors (EFs). Tests with 25 % fuel moisture were conducted with predominant smoldering combustion conditions (average modified combustion efficiency (MCE) =0.82+/-0.08). Average fuel-based EFCO2 (carbon dioxide) are highest (1400 +/- 38 g kg(-1)) and lowest (1073 +/- 63 g kg(-1)) for the Alaskan and Russian peats, respectively. EFCO (carbon monoxide) and EFCH4 (methane) are similar to 12 %15 % and similar ...


Chemostratigraphic Correlations Across The First Major Trilobite Extinction And Faunal Turnovers Between Laurentia And South China, Jih-Pai Lin, Frederick A. Sunberg, Ganqing Jiang, Isabel P. Montanez, Thomas Wotte Nov 2019

Chemostratigraphic Correlations Across The First Major Trilobite Extinction And Faunal Turnovers Between Laurentia And South China, Jih-Pai Lin, Frederick A. Sunberg, Ganqing Jiang, Isabel P. Montanez, Thomas Wotte

Geoscience Faculty Publications

During Cambrian Stage 4 (~514 Ma) the oceans were widely populated with endemic trilobites and three major faunas can be distinguished: olenellids, redlichiids, and paradoxidids. The lower–middle Cambrian boundary in Laurentia was based on the first major trilobite extinction event that is known as the Olenellid Biomere boundary. However, international correlation across this boundary (the Cambrian Series 2–Series 3 boundary) has been a challenge since the formal proposal of a four-series subdivision of the Cambrian System in 2005. Recently, the base of the international Cambrian Series 3 and of Stage 5 has been named as the base of ...


Trends And Disparities In Self-Reported And Measured Osteoporosis Among Us Adults, 2007-2014., Qing Wu, Yingke Xu, Ge Lin Nov 2019

Trends And Disparities In Self-Reported And Measured Osteoporosis Among Us Adults, 2007-2014., Qing Wu, Yingke Xu, Ge Lin

Environmental & Occupational Health Faculty Publications

(1) Background: Studies examining osteoporosis trends among US adults by different socioeconomic status (SES) are limited. The prevalence of self-reported osteoporosis in the US is rarely reported. (2) Methods: Data from the National Health and Nutritional Examination Survey (NHANES) between 2007–2008 and 2013–2014 cycles were analyzed. Age-adjusted prevalence of self-reported and that of measured osteoporosis were calculated overall and by sex, race/ethnicity, education attainment, and SES. (3) Results: The prevalence of self-reported osteoporosis was higher than that of measured osteoporosis in all three survey cycles for women, and in 2007–2008 and 2009–2010 for men. Participants ...


Biological And Practical Implications Of Genome-Wide Association Study Of Schizophrenia Using Bayesian Variable Selection, Benazir Rowe, Xiangning Chen, Zuoheng Wang, Jingchun Chen, Amei Amei Nov 2019

Biological And Practical Implications Of Genome-Wide Association Study Of Schizophrenia Using Bayesian Variable Selection, Benazir Rowe, Xiangning Chen, Zuoheng Wang, Jingchun Chen, Amei Amei

School of Medicine Faculty Publications

Genome-wide association studies (GWAS) have identified over 100 loci associated with schizophrenia. Most of these studies test genetic variants for association one at a time. In this study, we performed GWAS of the molecular genetics of schizophrenia (MGS) dataset with 5334 subjects using multivariate Bayesian variable selection (BVS) method Posterior Inference via Model Averaging and Subset Selection (piMASS) and compared our results with the previous univariate analysis of the MGS dataset. We showed that piMASS can improve the power of detecting schizophrenia-associated SNPs, potentially leading to new discoveries from existing data without increasing the sample size. We tested SNPs in ...


Bis(Tetra­Phenyl­Arsonium) Hexa­Fluorido­Technetate(Iv) Dihydrate: Preparation, Structure And Spectroscopic Analysis, Samundeeswari Mariappan Balasekaran, Frederic Poineau Nov 2019

Bis(Tetra­Phenyl­Arsonium) Hexa­Fluorido­Technetate(Iv) Dihydrate: Preparation, Structure And Spectroscopic Analysis, Samundeeswari Mariappan Balasekaran, Frederic Poineau

Chemistry and Biochemistry Faculty Publications

Reports of quadrivalent transition-metal fluoride salts containing bulky organic cations are limited. In this context, we prepared the bis­(tetra­phenyl­arsonium) hexa­fluorido­technetate(IV) dihydrate salt, (C24H20As)2[TcF6]·2H2O, by a cation metathesis reaction of (NH4)2[TcF6] in water. This is the first report of an arsonium salt of the hexa­fluorido­technetate(IV) dianion. (AsPh4)2[TcF6]·2H2O crystallizes in the triclinic space group P[\overline{1}]. The [TcF6]2− anion adopts a slightly distorted octa­hedral geometry with an average Tc—F bond length of 1.933 Å. The cyclic voltammogram of (AsPh4)2 ...


Smooth Flow In Diamond: Atomistic Ductility And Electronic Conductivity, Chang Liu, Xianqi Song, Quan Li, Yanming Ma, Changfeng Chen Nov 2019

Smooth Flow In Diamond: Atomistic Ductility And Electronic Conductivity, Chang Liu, Xianqi Song, Quan Li, Yanming Ma, Changfeng Chen

Physics & Astronomy Faculty Publications

Diamond is the quintessential superhard material widely known for its stiff and brittle nature and large electronic band gap. In stark contrast to these established benchmarks, our first-principles studies unveil surprising intrinsic structural ductility and electronic conductivity in diamond under coexisting large shear and compressive strains. These complex loading conditions impede brittle fracture modes and promote atomistic ductility, triggering rare smooth plastic flow in the normally rigid diamond crystal. This extraordinary structural change induces a concomitant band gap closure, enabling smooth charge flow in deformation created conducting channels. These startling soft-and-conducting modes reveal unprecedented fundamental characteristics of diamond, with profound ...


Design And Modeling Of A New Biomimetic Soft Robotic Jellyfish Using Ipmc-Based Electroactive Polymers, Zakai J. Olsen, Kwang J. Kim Nov 2019

Design And Modeling Of A New Biomimetic Soft Robotic Jellyfish Using Ipmc-Based Electroactive Polymers, Zakai J. Olsen, Kwang J. Kim

Mechanical Engineering Faculty Publications

Smart materials and soft robotics have been seen to be particularly well-suited for developing biomimetic devices and are active fields of research. In this study, the design and modeling of a new biomimetic soft robot is described. Initial work was made in the modeling of a biomimetic robot based on the locomotion and kinematics of jellyfish. Modifications were made to the governing equations for jellyfish locomotion that accounted for geometric differences between biology and the robotic design. In particular, the capability of the model to account for the mass and geometry of the robot design has been added for better ...


Nonideal Mhd Simulation Of Hl Tau Disk: Formation Of Rings, Xiao Hu, Zhaohuan Zhu, Satoshi Okuzumi, Xue-Ning Bai, Lile Wang, Kengo Tomida, James M. Stone Oct 2019

Nonideal Mhd Simulation Of Hl Tau Disk: Formation Of Rings, Xiao Hu, Zhaohuan Zhu, Satoshi Okuzumi, Xue-Ning Bai, Lile Wang, Kengo Tomida, James M. Stone

Physics & Astronomy Faculty Publications

Recent high-resolution observations unveil ring structures in circumstellar disks. The origin of these rings has been widely investigated under various theoretical scenarios. In this work we perform global 3D nonideal MHD simulations including effects from both ohmic resistivity and ambipolar diffusion (AD) to model the HL Tau disk. The nonideal MHD diffusion profiles are calculated based on the global dust evolution calculation including sintering effects. Disk ionization structure changes dramatically across the snow line due to the change of dust size distribution close to the snow line of major volatiles. We find that accretion is mainly driven by disk wind ...


Effects Of Rate Of Drying, Life History Phase, And Ecotype On The Ability Of The Moss Bryum Argenteum To Survive Desiccation Events And The Influence On Conservation And Selection Of Material For Restoration, Joshua Lee Greenwood, Lloyd R. Stark, Lindsay P. Chiquoine Oct 2019

Effects Of Rate Of Drying, Life History Phase, And Ecotype On The Ability Of The Moss Bryum Argenteum To Survive Desiccation Events And The Influence On Conservation And Selection Of Material For Restoration, Joshua Lee Greenwood, Lloyd R. Stark, Lindsay P. Chiquoine

Life Sciences Faculty Publications

Desiccation stress is frequently experienced by the moss Bryum argenteum and can influence survival, propagation and niche selection. We attempted to disentangle the interacting factors of life history phase (five categories) and rate of desiccation (time allotted for induction of desiccation tolerance) for 13 ecotypes of B. argenteum. Using chlorophyll fluorescence as a stress index, we determined how these parameters influenced desiccation tolerance. Rate of drying and life phase significantly affected desiccation tolerance. The reaction norms of desiccation tolerance displayed by the 13 ecotypes showed a substantial degree of variation in phenotypic plasticity. We observed differences in survival and fluorescence ...


Synchrotron Self-Compton Emission From External Shocks As The Origin Of The Sub-Tev Emission In Grb 180720b And Grb 190114c, Xiang-Yu Wang, Ruo-Yu Liu, Hai-Ming Zhang, Shao-Qiang Xi, Bing Zhang Oct 2019

Synchrotron Self-Compton Emission From External Shocks As The Origin Of The Sub-Tev Emission In Grb 180720b And Grb 190114c, Xiang-Yu Wang, Ruo-Yu Liu, Hai-Ming Zhang, Shao-Qiang Xi, Bing Zhang

Physics & Astronomy Faculty Publications

Recently, very high-energy photons above 100 GeV were reported to be detected from GRB 190114C and GRB 180720B at, respectively, 100–1000 s and 10 hr after the burst. We model the available broadband data of both GRBs with the synchrotron plus synchrotron self-Compton (SSC) emission of the afterglow shocks. We find that the sub-TeV emission of GRB 180720B can be interpreted as the SSC emission from afterglow shocks expanding in a constant-density circumburst medium. The SSC emission of GRB 190114C dominates over the synchrotron component from GeV energies at ~100 s, which can explain the possible hard spectrum of ...


Changes In Pm2.5 Peat Combustion Source Profiles With Atmospheric Aging In An Oxidation Flow Reactor, Judith C. Chow, Junji Cao, Lung-Wen Anthony Chen, Xiaoliang Wang, Qiyuan Wang, Jie Tian, Steven Sai Hang Ho, Adam C. Watts, Tessa B. Carlson, Steven D. Kohl, John G. Watson Oct 2019

Changes In Pm2.5 Peat Combustion Source Profiles With Atmospheric Aging In An Oxidation Flow Reactor, Judith C. Chow, Junji Cao, Lung-Wen Anthony Chen, Xiaoliang Wang, Qiyuan Wang, Jie Tian, Steven Sai Hang Ho, Adam C. Watts, Tessa B. Carlson, Steven D. Kohl, John G. Watson

Environmental & Occupational Health Faculty Publications

Smoke from laboratory chamber burning of peat fuels from Russia, Siberia, the USA (Alaska and Florida), and Malaysia representing boreal, temperate, subtropical, and tropical regions was sampled before and after passing through a potential-aerosol-mass oxidation flow reactor (PAM-OFR) to simulate intermediately aged (∼2 d) and well-aged (∼7 d) source profiles. Species abundances in PM2.5 between aged and fresh profiles varied by several orders of magnitude with two distinguishable clusters, centered around 0.1 % for reactive and ionic species and centered around 10 % for carbon. Organic carbon (OC) accounted for 58 %–85 % of PM2.5 mass in fresh profiles with ...


"Double-Tracking" Characteristics Of The Spectral Evolution Of Grb 131231a: Synchrotron Origin?, Liang Li, Jin-Jun Geng, Yan-Zhi Meng, Xue-Feng Wu, Yong-Feng Huang, Yu Wang, Rahim Moradi, Lucas Uhm, Bing Zhang Oct 2019

"Double-Tracking" Characteristics Of The Spectral Evolution Of Grb 131231a: Synchrotron Origin?, Liang Li, Jin-Jun Geng, Yan-Zhi Meng, Xue-Feng Wu, Yong-Feng Huang, Yu Wang, Rahim Moradi, Lucas Uhm, Bing Zhang

Physics & Astronomy Faculty Publications

The characteristics of the spectral evolution of the prompt emission of gamma-ray bursts (GRBs), which are closely related to the radiation mechanism (synchrotron or photosphere), are still an unsolved subject. Here, by performing the detailed time-resolved spectral fitting of GRB 131231A, which has a very bright and well-defined single pulse, some interesting spectral evolution features have been found. (i) Both the low-energy spectral index α and the peak energy E p exhibit the "flux-tracking" pattern ("double-tracking" characteristics). (ii) The parameter relations, i.e., F (the energy flux)-α, F–E p, and E p–α, along with the analogous Yonetoku ...


An Ideal Testbed For Planet-Disk Interaction: Two Giant Protoplanets In Resonance Shaping The Pds 70 Protoplanetary Disk, Jaehan Bae, Zhaohuan Zhu, Clément Baruteau, Myriam Benisty, Cornelis P. Dullemong, Stefano Facchini, Andrea Isella, Miriam Keppler, Laura M. Pérez, Richard Teague Oct 2019

An Ideal Testbed For Planet-Disk Interaction: Two Giant Protoplanets In Resonance Shaping The Pds 70 Protoplanetary Disk, Jaehan Bae, Zhaohuan Zhu, Clément Baruteau, Myriam Benisty, Cornelis P. Dullemong, Stefano Facchini, Andrea Isella, Miriam Keppler, Laura M. Pérez, Richard Teague

Physics & Astronomy Faculty Publications

While numerical simulations have been playing a key role in the studies of planet–disk interaction, testing numerical results against observations has been limited so far. With the two directly imaged protoplanets embedded in its circumstellar disk, PDS 70 offers an ideal testbed for planet–disk interaction studies. Using two-dimensional hydrodynamic simulations we show that the observed features can be well explained with the two planets in formation, providing strong evidence that previously proposed theories of planet–disk interaction are in action, including resonant migration, particle trapping, size segregation, and filtration. Our simulations suggest that the two planets are likely ...


Diagnosing 0.1–10 Au Scale Morphology Of The Fu Ori Disk Using Alma And Vlti/Gravity, Hauyu Baobab Liu, Antoine Merand, Joel D. Green, Sebastian Perez, Antonio S. Hales, Yao-Lun Yang, Michael M. Dunham, Yasuhiro Hasegawa, Thomas Henning, Roberto Galvin-Madrid, Agnes Kospal, Michihiro Takami, Eduardo I. Vorobyov, Zhaohuan Zhu Oct 2019

Diagnosing 0.1–10 Au Scale Morphology Of The Fu Ori Disk Using Alma And Vlti/Gravity, Hauyu Baobab Liu, Antoine Merand, Joel D. Green, Sebastian Perez, Antonio S. Hales, Yao-Lun Yang, Michael M. Dunham, Yasuhiro Hasegawa, Thomas Henning, Roberto Galvin-Madrid, Agnes Kospal, Michihiro Takami, Eduardo I. Vorobyov, Zhaohuan Zhu

Physics & Astronomy Faculty Publications

We report new Atacama Large Millimeter/submillimeter Array Band 3 (86–100 GHz; ~80 mas angular resolution) and Band 4 (146–160 GHz; ~50 mas angular resolution) observations of the dust continuum emission toward the archetypal and ongoing accretion burst young stellar object FU Ori, which simultaneously covered its companion, FU Ori S. In addition, we present near-infrared (2–2.45 μm) observations of FU Ori taken with the General Relativity Analysis via VLT InTerferometrY (GRAVITY; ~1 mas angular resolution) instrument on the Very Large Telescope Interferometer (VLTI). We find that the emission in both FU Ori and FU Ori ...


A Dynamic Quantitative Microbial Risk Assessment For Norovirus In Potable Reuse System, Erfaneh Amoueyan, Sajjad Ahmad, Joseph N.S. Eisenberg, Daniel Gerrity Oct 2019

A Dynamic Quantitative Microbial Risk Assessment For Norovirus In Potable Reuse System, Erfaneh Amoueyan, Sajjad Ahmad, Joseph N.S. Eisenberg, Daniel Gerrity

Civil & Environmental Engineering and Construction Faculty Publications

This study describes the results of a dynamic quantitative microbial risk assessment (QMRA) for norovirus (NoV) that was used to evaluate the relative significance of foodborne, person-to-person, and person-to-sewage-to-person transmission pathways. This last pathway was incorporated into simulated potable reuse systems to evaluate the adequacy of typical treatment trains, operational conditions, and regulatory frameworks. The results confirm that secondary and foodborne transmission dominate the overall risk calculation and that waterborne NoV likely contributes no appreciable public health risk, at least in the scenarios modeled in this study. De facto reuse with an environmental buffer storage time of at least 30 ...


The Frb 121102 Host Is Atypical Among Nearby Fast Radio Bursts, Ye Li, Bing Zhang, Kentaro Nagamine, Jingjing Shi Oct 2019

The Frb 121102 Host Is Atypical Among Nearby Fast Radio Bursts, Ye Li, Bing Zhang, Kentaro Nagamine, Jingjing Shi

Physics & Astronomy Faculty Publications

We search for host galaxy candidates of nearby fast radio bursts (FRBs), FRB 180729.J1316+55, FRB 171020, FRB 171213, FRB 180810.J1159+83, and FRB 180814.J0422+73 (the second repeating FRB). We compare the absolute magnitudes and the expected host dispersion measure DMhost of these candidates with that of the first repeating FRB, FRB 121102, as well as those of long gamma-ray bursts (LGRBs) and superluminous supernovae (SLSNe), the proposed progenitor systems of FRB 121102. We find that while the FRB 121102 host is consistent with those of LGRBs and SLSNe, the nearby FRB host candidates, at least ...


Reproduction And Dispersal Of Biological Soil Crust Organisms, Steven D. Warren, Larry L. St. Clair, Lloyd R. Stark, Louise A. Lewis, Nuttapon Pombubpa, Tania Kurbessoian, Jason E. Stajich, Zachary T. Aanderud Oct 2019

Reproduction And Dispersal Of Biological Soil Crust Organisms, Steven D. Warren, Larry L. St. Clair, Lloyd R. Stark, Louise A. Lewis, Nuttapon Pombubpa, Tania Kurbessoian, Jason E. Stajich, Zachary T. Aanderud

Life Sciences Faculty Publications

Biological soil crusts (BSCs) consist of a diverse and highly integrated community of organisms that effectively colonize and collectively stabilize soil surfaces. BSCs vary in terms of soil chemistry and texture as well as the environmental parameters that combine to support unique combinations of organisms—including cyanobacteria dominated, lichen-dominated, and bryophyte-dominated crusts. The list of organismal groups that make up BSC communities in various and unique combinations include—free living, lichenized, and mycorrhizal fungi, chemoheterotrophic bacteria, cyanobacteria, diazotrophic bacteria and archaea, eukaryotic algae, and bryophytes. The various BSC organismal groups demonstrate several common characteristics including—desiccation and extreme temperature tolerance ...


Relativistic Astronomy. Iii. Test Of Special Relativity Via Doppler Effect, Yuan-Pei Yang, Jin-Peng Zhu, Bing Zhang Sep 2019

Relativistic Astronomy. Iii. Test Of Special Relativity Via Doppler Effect, Yuan-Pei Yang, Jin-Peng Zhu, Bing Zhang

Physics & Astronomy Faculty Publications

The "Breakthrough Starshot" program is planning to send transrelativistic probes to travel to nearby stellar systems within decades. Because the probe velocity is designed to be a good fraction of the light speed, Zhang & Li recently proposed that these transrelativistic probes can be used to study astronomical objects and to test special relativity. In this work, we propose some methods to test special relativity and constrain photon mass using the Doppler effect with the images and spectral features of astronomical objects as observed in the transrelativistic probes. We introduce more general theories to set up the framework of testing special ...


A Global View Of The Inner Accretion And Ejection Flow Around Super Massive Black Holes, Margherita Giustini, Daniel Proga Sep 2019

A Global View Of The Inner Accretion And Ejection Flow Around Super Massive Black Holes, Margherita Giustini, Daniel Proga

Physics & Astronomy Faculty Publications

Context. Understanding the physics and geometry of accretion and ejection around super massive black holes (SMBHs) is important to understand the evolution of active galactic nuclei (AGN) and therefore of the large scale structures of the Universe. Aims. We aim at providing a simple, coherent, and global view of the sub-parsec accretion and ejection flow in AGN with varying Eddington ratio, ṁ, and black hole mass, MBH. Methods. We made use of theoretical insights, results of numerical simulations, as well as UV and X-ray observations to review the inner regions of AGN by including different accretion and ejection modes, with ...


Numerical Simulation Based Targeting Of The Magushan Skarn Cu-Mo Deposit, Middle-Lower Yangtze Metallogenic Belt, China, Xunyu Hu, Xiaohui Li, Feng Yuan, Alison Ord, Simon M. Jowitt, Yue Li, Wenqiang Dai, Rui Ye, Taofa Zhou Sep 2019

Numerical Simulation Based Targeting Of The Magushan Skarn Cu-Mo Deposit, Middle-Lower Yangtze Metallogenic Belt, China, Xunyu Hu, Xiaohui Li, Feng Yuan, Alison Ord, Simon M. Jowitt, Yue Li, Wenqiang Dai, Rui Ye, Taofa Zhou

Geoscience Faculty Publications

The Magushan Cu–Mo deposit is a skarn deposit within the Nanling–Xuancheng mining district of the Middle-Lower Yangtze River Metallogenic Belt (MLYRMB), China. This study presents the results of a new numerical simulation that models the ore-forming processes that generated the Magushan deposit and enables the identification of unexplored areas that have significant exploration potential under areas covered by thick sedimentary sequences that cannot be easily explored using traditional methods. This study outlines the practical value of numerical simulation in determining the processes that operate during mineral deposit formation and how this knowledge can be used to enhance exploration ...


Polar Alignment Of A Protoplanetary Disc Around An Eccentric Binary – Iii. Effect Of Disc Mass, Rebecca G. Martin, Stephen H. Lubow Sep 2019

Polar Alignment Of A Protoplanetary Disc Around An Eccentric Binary – Iii. Effect Of Disc Mass, Rebecca G. Martin, Stephen H. Lubow

Physics & Astronomy Faculty Publications

An initially sufficiently misaligned low-mass protoplanetary disc around an eccentric binary undergoes damped nodal oscillations of tilt angle and longitude of ascending node. Dissipation causes evolution towards a stationary state of polar alignment in which the disc lies perpendicular to the binary orbital plane with angular momentum aligned to the eccentricity vector of the binary. We use hydrodynamic simulations and analytical methods to investigate how the mass of the disc affects this process. The simulations suggest that a disc with non-zero mass settles into a stationary state in the frame of the binary, the generalized polar state, at somewhat lower ...


The Radial Distribution Of Dust Particles In The Hl Tau Disk From Alma And Vla Observations, Carlos Carrasco-Gonzalez, Anibal Sierra, Mario Flock, Zhaohuan Zhu, Thomas Henning, Claire Chandler, Roberto Galvan-Madrid, Enrique Macias, Guillem Anglada, Hendrik Linz, Mayra Osorio, Luis F. Rodriguez, Leonardo Testi, Jose M. Torrelles, Laura Perez, Yao Liu Sep 2019

The Radial Distribution Of Dust Particles In The Hl Tau Disk From Alma And Vla Observations, Carlos Carrasco-Gonzalez, Anibal Sierra, Mario Flock, Zhaohuan Zhu, Thomas Henning, Claire Chandler, Roberto Galvan-Madrid, Enrique Macias, Guillem Anglada, Hendrik Linz, Mayra Osorio, Luis F. Rodriguez, Leonardo Testi, Jose M. Torrelles, Laura Perez, Yao Liu

Physics & Astronomy Faculty Publications

Understanding planet formation requires one to discern how dust grows in protoplanetary disks. An important parameter to measure in disks is the maximum dust grain size present. This is usually estimated through measurements of the dust opacity at different millimeter wavelengths assuming optically thin emission and dust opacity dominated by absorption. However, Atacama Large Millimeter/submillimeter Array (ALMA) observations have shown that these assumptions might not be correct in the case of protoplanetary disks, leading to overestimation of particle sizes and to underestimation of the disk's mass. Here, we present an analysis of high-quality ALMA and Very Large Array ...


Literature Review: Biocement For Stabilization Of Expansive Soils In Las Vegas, Nevada, Silva Topchyan, Moses Karakouzian Sep 2019

Literature Review: Biocement For Stabilization Of Expansive Soils In Las Vegas, Nevada, Silva Topchyan, Moses Karakouzian

LSAMP Poster Presentations

The aim of this study was to present a possibility for the use of biocementon expansive clay. Expansive soil is a type of clay when exposed to water and moisture changes its volume. Due to the clays swelling and shrinkage behavior itsdifficult to use it in engineering and construction projects, therefore costly and unhealthy techniques have been used to stabiliseexpansive soil in order to address the problem [12]. A possible healthy and environmentally friendly solution is Biocement which uses microbial induced calcite precipitation (MICP) in order to help aggregate soil to form a stable cementitiousmaterial. MICP isdependent on the innate ...