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Articles 1291 - 1320 of 6056

Full-Text Articles in Physical Sciences and Mathematics

Learning Curve Analysis Using Intensive Longitudinal And Cluster-Correlated Data, Xiao Zhong, Zeyi Sun, Haoyi Xiong, Neil Heffernan, Md Monirul Islam Nov 2017

Learning Curve Analysis Using Intensive Longitudinal And Cluster-Correlated Data, Xiao Zhong, Zeyi Sun, Haoyi Xiong, Neil Heffernan, Md Monirul Islam

Engineering Management and Systems Engineering Faculty Research & Creative Works

Intensive longitudinal and cluster-correlated data (ILCCD) can be generated in any situation where numerical or categorical characteristics of multiple individuals or study units are observed and measured at tens, hundreds, or thousands of occasions. The spacing of measurements in time for each individual can be regular or irregular, fixed or random, and the number of characteristics measured at each occasion may be few or many. Such data can also arise in situations involving continuous-time measurements of recurrent events. Generalized linear models (GLMs) are usually considered for the analysis of correlated non-normal data, while multivariate analysis of variance (MANOVA) is another …

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Neutrino Pair Cerenkov Radiation For Tachyonic Neutrinos, Ulrich D. Jentschura, Istvan Nandori Nov 2017

Neutrino Pair Cerenkov Radiation For Tachyonic Neutrinos, Ulrich D. Jentschura, Istvan Nandori

Physics Faculty Research & Creative Works

The emission of a charged light lepton pair by a superluminal neutrino has been identified as a major factor in the energy loss of highly energetic neutrinos. The observation of PeV neutrinos by IceCube implies their stability against lepton pair Cerenkov radiation. Under the assumption of a Lorentz-violating dispersion relation for highly energetic superluminal neutrinos, one may thus constrain the Lorentz-violating parameters. A kinematically different situation arises when one assumes a Lorentz-covariant, space-like dispersion relation for hypothetical tachyonic neutrinos, as an alternative to Lorentz-violating theories. We here discuss a hitherto neglected decay process, where a highly energetic tachyonic neutrino may …

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Search For High-Energy Neutrinos From Binary Neutron Star Merger Gw170817 With Antares, Icecube, And The Pierre Auger Observatory, A. Albert, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Nov 2017

Search For High-Energy Neutrinos From Binary Neutron Star Merger Gw170817 With Antares, Icecube, And The Pierre Auger Observatory, A. Albert, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

The Advanced LIGO and Advanced Virgo observatories recently discovered gravitational waves from a binary neutron star inspiral. A short gamma-ray burst (GRB) that followed the merger of this binary was also recorded by the Fermi Gamma-ray Burst Monitor (Fermi-GBM), and the Anti-Coincidence Shield for the Spectrometer for the International Gamma-Ray Astrophysics Laboratory (INTEGRAL), indicating particle acceleration by the source. The precise location of the event was determined by optical detections of emission following the merger. We searched for high-energy neutrinos from the merger in the GeV-EeV energy range using the Antares, IceCube, and Pierre Auger Observatories. No neutrinos …

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Enhanced Optical Coupling And Raman Scattering Via Microscopic Interface Engineering, Jonathan V. Thompson, Brett H. Hokr, Wihan Kim, Charles W. Ballmann, Brian E. Applegate, Javier Jo, Alexey Yamilov, Hui Cao, Marlan O. Scully, Vladislav V. Yakovlev Nov 2017

Enhanced Optical Coupling And Raman Scattering Via Microscopic Interface Engineering, Jonathan V. Thompson, Brett H. Hokr, Wihan Kim, Charles W. Ballmann, Brian E. Applegate, Javier Jo, Alexey Yamilov, Hui Cao, Marlan O. Scully, Vladislav V. Yakovlev

Physics Faculty Research & Creative Works

Spontaneous Raman scattering is an extremely powerful tool for the remote detection and identification of various chemical materials. However, when those materials are contained within strongly scattering or turbid media, as is the case in many biological and security related systems, the sensitivity and range of Raman signal generation and detection is severely limited. Here, we demonstrate that through microscopic engineering of the optical interface, the optical coupling of light into a turbid material can be substantially enhanced. This improved coupling facilitates the enhancement of the Raman scattering signal generated by molecules within the medium. In particular, we detect at …

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A Framework For Incorporating The Impact Of Water Quality On Water Supply Stress: An Example From Louisiana, David M. Borrok, Jian Chen, Hisham Eldardiry, Emad Habib Oct 2017

A Framework For Incorporating The Impact Of Water Quality On Water Supply Stress: An Example From Louisiana, David M. Borrok, Jian Chen, Hisham Eldardiry, Emad Habib

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

Water of poor quality can directly impact the budget of water available for key user groups. Despite this importance, methods for quantifying the impact of water quality on water availability remain elusive. Here, we develop a new framework for incorporating the impact of water quality on water supply by modifying the Water Supply Stress Index (WaSSI). We demonstrate the usefulness of the framework by investigating the impact of high salinity waters on the availability of irrigation water for agriculture in Louisiana. The WaSSI was deconstructed into sectoral components such that the total available water supply could be reduced for a …

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Investigation Of The Ozone Formation Reaction Pathway: Comparisons Of Full Configuration Interaction Quantum Monte Carlo And Fixed-Node Diffusion Monte Carlo With Contracted And Uncontracted Mrci, Andrew D. Powell, Nikesh S. Dattani, Rene F. K. Spada, Francisco B. C. Machado, Hans Lischka, Richard Dawes Oct 2017

Investigation Of The Ozone Formation Reaction Pathway: Comparisons Of Full Configuration Interaction Quantum Monte Carlo And Fixed-Node Diffusion Monte Carlo With Contracted And Uncontracted Mrci, Andrew D. Powell, Nikesh S. Dattani, Rene F. K. Spada, Francisco B. C. Machado, Hans Lischka, Richard Dawes

Chemistry Faculty Research & Creative Works

The association/dissociation reaction path for ozone (O2 + O ↔ O3) is notoriously difficult to describe accurately using ab initio electronic structure theory, due to the importance of both strong and dynamic electron correlations. Experimentally, spectroscopic studies of the highest lying recorded vibrational states combined with the observed negative temperature dependence of the kinetics of oxygen isotope exchange reactions confirm that the reaction is barrierless, consistent with the latest potential energy surfaces. Previously reported potentials based on Davidson-corrected internally contracted multireference configuration interaction (MRCI) suffer from a spurious reef feature in the entrance channel even when extrapolated …

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Characterization Of The Ornithine Hydroxylation Step In Albachelin Biosynthesis, Kendra Bufkin, Pablo Sobrado Oct 2017

Characterization Of The Ornithine Hydroxylation Step In Albachelin Biosynthesis, Kendra Bufkin, Pablo Sobrado

Chemistry Faculty Research & Creative Works

N-Hydroxylating monooxygenases (NMOs) are involved in siderophore biosynthesis. Siderophores are high affinity iron chelators composed of catechol and hydroxamate functional groups that are synthesized and secreted by microorganisms and plants. Recently, a new siderophore named albachelin was isolated from a culture of Amycolatopsis alba growing under iron-limiting conditions. This work focuses on the expression, purification, and characterization of the NMO, abachelin monooxygenase (AMO) from A. alba. This enzyme was purified and characterized in its holo (FAD-bound) and apo (FAD-free) forms. The apo-AMO could be reconstituted by addition of free FAD. The two forms of AMO hydroxylate ornithine, while lysine increases …

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Gw170817: Observation Of Gravitational Waves From A Binary Neutron Star Inspiral, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Oct 2017

Gw170817: Observation Of Gravitational Waves From A Binary Neutron Star Inspiral, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

On August 17, 2017 at 12-41:04 UTC the Advanced LIGO and Advanced Virgo gravitational-wave detectors made their first observation of a binary neutron star inspiral. The signal, GW170817, was detected with a combined signal-to-noise ratio of 32.4 and a false-alarm-rate estimate of less than one per 8.0 x 104 years. We infer the component masses of the binary to be between 0.86 and 2.26 M⊙, in agreement with masses of known neutron stars. Restricting the component spins to the range inferred in binary neutron stars, we find the component masses to be in the range 1.17-1.60 M …

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Multi-Messenger Observations Of A Binary Neutron Star Merger, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Oct 2017

Multi-Messenger Observations Of A Binary Neutron Star Merger, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

On 2017 August 17 a binary neutron star coalescence candidate (later designated GW170817) with merger time 12:41:04 UTC was observed through gravitational waves by the Advanced LIGO and Advanced Virgo detectors. The Fermi Gamma-ray Burst Monitor independently detected a gamma-ray burst (GRB 170817A) with a time delay of ~1.7 s with respect to the merger time. From the gravitational-wave signal, the source was initially localized to a sky region of 31 deg2 at a luminosity distance of 40+ 8-8 Mpc and with component masses consistent with neutron stars. The component masses were later measured to be in …

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Gw170814: A Three-Detector Observation Of Gravitational Waves From A Binary Black Hole Coalescence, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Oct 2017

Gw170814: A Three-Detector Observation Of Gravitational Waves From A Binary Black Hole Coalescence, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

On August 14, 2017 at 10 30:43 UTC, the Advanced Virgo detector and the two Advanced LIGO detectors coherently observed a transient gravitational-wave signal produced by the coalescence of two stellar mass black holes, with a false-alarm rate of ≲1 in 27 000 years. The signal was observed with a three-detector network matched-filter signal-to-noise ratio of 18. The inferred masses of the initial black holes are 30.5-3.0+5.7M⊙ and 25.3-4.2+2.8M⊙ (at the 90% credible level). The luminosity distance of the source is 540-210+130 Mpc, corresponding to a redshift of z=0.11-0.04+0.03 …

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Aeromagnetic, Gravity, And Differential Interferometric Synthetic Aperture Radar Analyses Reveal The Causative Fault Of The 3 April 2017 MW 6.5 Moiyabana, Botswana, Earthquake, Folarin Kolawole, Estella A. Atekwana, S. Malloy, Dorothy Sarah Stamps, Raphael Grandin, Mohamed G. Abdel Salam, Khumo Leseane, Elisha M. Shemang Sep 2017

Aeromagnetic, Gravity, And Differential Interferometric Synthetic Aperture Radar Analyses Reveal The Causative Fault Of The 3 April 2017 MW 6.5 Moiyabana, Botswana, Earthquake, Folarin Kolawole, Estella A. Atekwana, S. Malloy, Dorothy Sarah Stamps, Raphael Grandin, Mohamed G. Abdel Salam, Khumo Leseane, Elisha M. Shemang

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

On 3 April 2017, a Mw 6.5 earthquake struck Moiyabana, Botswana, nucleating at >20 km focal depth within the Paleoproterozoic Limpopo-Shashe orogenic belt separating the Archean Zimbabwe and Kaapvaal Cratons. We investigate the lithospheric structures associated with this earthquake using high-resolution aeromagnetic and gravity data integrated with Differential Interferometric Synthetic Aperture Radar (DInSAR) analysis. Here we present the first results that provide insights into the tectonic framework of the earthquake. The ruptured fault trace delineated by DInSAR aligns with a distinct NW striking and NE dipping magnetic lineament within the Precambrian basement. The fault plane solution and numerical modeling …

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Augmenting Amdahl's Second Law: A Theoretical Model To Build Cost-Effective Balanced Hpc Infrastructure For Data-Driven Science, Arghya Kusum Das, Jaeki Hong, Sayan Goswami, Richard Platania, Kisung Lee, Wooseok Chang, Seung Jong Park, Ling Liu Sep 2017

Augmenting Amdahl's Second Law: A Theoretical Model To Build Cost-Effective Balanced Hpc Infrastructure For Data-Driven Science, Arghya Kusum Das, Jaeki Hong, Sayan Goswami, Richard Platania, Kisung Lee, Wooseok Chang, Seung Jong Park, Ling Liu

Computer Science Faculty Research & Creative Works

High-performance analysis of big data demands more computing resources, forcing similar growth in computation cost. So, the challenge to the HPC system designers is providing not only high performance but also high performance at lower cost. For high performance yet cost-effective cyberinfrastructure, we propose a new system model augmenting Amdahl's second law for balanced system to optimize price-performance-ratio. We express the optimal balance among CPU-speed, I/O-bandwidth and DRAM-size (i.e., Amdahl's I/O-and memory-number) in terms of application characteristics and hardware cost. Considering Xeon processor and recent hardware prices, we showed that a system needs almost 0.17GBPS I/O-bandwidth and 3GB DRAM per …

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Coflourish: An Sdn-Assisted Coflow Scheduling Framework For Clouds, Chui Hui Chiu, Dipak Kumar Singh, Qingyang Wang, Seung Jong Park Sep 2017

Coflourish: An Sdn-Assisted Coflow Scheduling Framework For Clouds, Chui Hui Chiu, Dipak Kumar Singh, Qingyang Wang, Seung Jong Park

Computer Science Faculty Research & Creative Works

Existing coflow scheduling frameworks effectively shorten communication time and completion time of cluster applications. However, existing frameworks only consider available bandwidth on hosts and overlook congestion in the network when making scheduling decisions. Through extensive simulations using the realistic workload probability distribution from Facebook, we observe the performance degradation of the state-of-the-art coflow scheduling framework, Varys, in the cloud environment on a shared data center network (DCN) because of the lack of network congestion information. We propose Coflourish, the first coflow scheduling framework that exploits the congestion feedback assistances from the software-defined-networking (SDN)-enabled switches in the networks for available bandwidth …

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Minimal Coflow Routing And Scheduling In Openflow-Based Cloud Storage Area Networks, Chui Hui Chiu, Dipak Kumar Singh, Qingyang Wang, Kisung Lee, Seung Jong Park Sep 2017

Minimal Coflow Routing And Scheduling In Openflow-Based Cloud Storage Area Networks, Chui Hui Chiu, Dipak Kumar Singh, Qingyang Wang, Kisung Lee, Seung Jong Park

Computer Science Faculty Research & Creative Works

Researches affirm that coflow scheduling/routing substantially shortens the average application inner communication time in data center networks (DCNs). The commonly desirable critical features of existing coflow scheduling/routing framework includes (1) coflow scheduling, (2) coflow routing, and (3) per-flow rate-limiting. However, to provide the 3 features, existing frameworks require customized computing frameworks, customized operating systems, or specific external commercial monitoring frameworks on software-defined networking (SDN) switches. These requirements defer or even prohibit the deployment of coflow scheduling/routing in production DCNs. In this paper, we design a coflow scheduling and routing framework, MinCOF which has minimal requirements on hosts and switches for …

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Robust Odd-Parity Superconductivity In The Doped Topological Insulator Nbₓbi₂Se₃, M. P. Smylie, K. Willa, H. Claus, A. Snezhko, I. Martin, W.-K. Kwok, Y. Qiu, Yew San Hor, E. Bokari, P. Niraula, A. Kayani, V. Mishra, U. Welp Sep 2017

Robust Odd-Parity Superconductivity In The Doped Topological Insulator Nbₓbi₂Se₃, M. P. Smylie, K. Willa, H. Claus, A. Snezhko, I. Martin, W.-K. Kwok, Y. Qiu, Yew San Hor, E. Bokari, P. Niraula, A. Kayani, V. Mishra, U. Welp

Physics Faculty Research & Creative Works

We present resistivity and magnetization measurements on proton-irradiated crystals demonstrating that the superconducting state in the doped topological insulator NbxBi2Se3 (x=0.25) is surprisingly robust against disorder-induced electron scattering. The superconducting transition temperature TC decreases without indication of saturation with increasing defect concentration, and the corresponding scattering rates far surpass expectations based on conventional theory. The low-temperature variation of the London penetration depth Δλ(T) follows a power law [Δλ(T)T2] indicating the presence of symmetry-protected point nodes. Our results are consistent with the proposed robust nematic Eu pairing state in this material.

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Upper Limits On Gravitational Waves From Scorpius X-1 From A Model-Based Cross-Correlation Search In Advanced Ligo Data, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Sep 2017

Upper Limits On Gravitational Waves From Scorpius X-1 From A Model-Based Cross-Correlation Search In Advanced Ligo Data, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We present the results of a semicoherent search for continuous gravitational waves from the low-mass X-ray binary Scorpius X-1, using data from the first Advanced LIGO observing run. The search method uses details of the modeled, parametrized continuous signal to combine coherently data separated by less than a specified coherence time, which can be adjusted to trade off sensitivity against computational cost. A search was conducted over the frequency range 25-2000 Hz, spanning the current observationally constrained range of binary orbital parameters. No significant detection candidates were found, and frequency-dependent upper limits were set using a combination of sensitivity estimates …

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Long-Range Interactions Of Hydrogen Atoms In Excited States. Iii. Ns−1s Interactions For N ≥ 3, Chandra M. Adhikari, V. Debierre, Ulrich D. Jentschura Sep 2017

Long-Range Interactions Of Hydrogen Atoms In Excited States. Iii. Ns−1s Interactions For N ≥ 3, Chandra M. Adhikari, V. Debierre, Ulrich D. Jentschura

Physics Faculty Research & Creative Works

The long-range interaction of excited neutral atoms has a number of interesting and surprising properties such as the prevalence of long-range oscillatory tails and the emergence of numerically large van der Waals C6 coefficients. Furthermore, the energetically quasidegenerate nP states require special attention and lead to mathematical subtleties. Here we analyze the interaction of excited hydrogen atoms in nS states (3 ≤ n ≤ 12) with ground-state hydrogen atoms and find that the C6 coefficients roughly grow with the fourth power of the principal quantum number and can reach values in excess of 240000 (in atomic units) for states …

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Recent Advances In Understanding The Structure And Properties Of Amorphous Oxide Semiconductors, Julia E. Medvedeva, D. B. Buchholz, Robert P. H. Chang Sep 2017

Recent Advances In Understanding The Structure And Properties Of Amorphous Oxide Semiconductors, Julia E. Medvedeva, D. B. Buchholz, Robert P. H. Chang

Physics Faculty Research & Creative Works

Amorphous oxide semiconductors (AOSs)--ternary or quaternary oxides of post-transition metals such as In-Sn-O, Zn-Sn-O, or In-Ga-Zn-O–have been known for a decade and have attracted a great deal of attention as they possess several technological advantages, including low-temperature large-area deposition, mechanical flexibility, smooth surfaces, and high carrier mobility that is an order of magnitude larger than that of amorphous silicon (a-Si:H). Compared to their crystalline counterparts, the structure of AOSs is extremely sensitive to deposition conditions, stoichiometry, and composition, giving rise to a wide range of tunable optical and electrical properties. The large parameter space and the resulting complex deposition--structure--property relationships …

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All-Sky Search For Periodic Gravitational Waves In The O1 Ligo Data, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website. Sep 2017

All-Sky Search For Periodic Gravitational Waves In The O1 Ligo Data, Benjamin P. Abbott, Marco Cavaglia, For Full List Of Authors, See Publisher's Website.

Physics Faculty Research & Creative Works

We report on an all-sky search for periodic gravitational waves in the frequency band 20-475 Hz and with a frequency time derivative in the range of [-1.0,+0.1] x 10-8 Hz/s. Such a signal could be produced by a nearby spinning and slightly nonaxisymmetric isolated neutron star in our galaxy. This search uses the data from Advanced LIGO's first observational run, O1. No periodic gravitational wave signals were observed, and upper limits were placed on their strengths. The lowest upper limits on worst-case (linearly polarized) strain amplitude h0 are ∼4 x 10-25 near 170 Hz. For a circularly …

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Defining Consciousness, Adam Bateman Aug 2017

Defining Consciousness, Adam Bateman

Missouri S&T’s Peer to Peer

A researcher trying to develop a conscious artificial intelligence or examine consciousness in plants would be completely unable to do so without first obtaining a clear, concise, and global definition. This idea is what originally inspired my research. The main method of research to be used will be to thoroughly examine scholarly articles pertaining to consciousness and different theories of the mind. After gathering data and different ideas, I will create a definition that is plausible, and is optimized in terms of being useful to researchers. Currently, the issue is that there are an incredible amount of mental features that …

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Biosensors For Cancer Detection Applications, Shannon Griffin Aug 2017

Biosensors For Cancer Detection Applications, Shannon Griffin

Missouri S&T’s Peer to Peer

Cancer is one of the most deadly diseases, and current detection options are ineffective. Recently, a large amount of research has been conducted for the development of biosensors able to detect cancer biomarkers. Many biosensors have been created for cancer detecting purposes. I examined literature reviews outlining current biosensing methods. These reviews provided an overview of the sensing techniques that are currently in existence as well as evaluations of their effectiveness. I also read experimental reports that outline the construction of biosensors fabricated in laboratories and the results of their testings. These papers help to showcase the feasibility and effectiveness …

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Exploring Potential Flaws And Dangers Involving Machine Learning Technology, David Nicholas Skoff Aug 2017

Exploring Potential Flaws And Dangers Involving Machine Learning Technology, David Nicholas Skoff

Missouri S&T’s Peer to Peer

This paper seeks to explore the ways in which machine learning and AI may influence the world in the future and the potential for the technology to be misused or exploited. In 1959 Arthur Samuel defined machine learning as “the field of study that gives computers the ability to learn without being explicitly programmed” (Munoz). This paper will also seek to find out if there is merit to the current worry that robots will take over some jobs based in cognitive abilities. In the past, a human was required to perform these jobs, but with the rise of more complex …

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Network Security: Internet Protocol Version Six Security, Hannah Reinbolt Aug 2017

Network Security: Internet Protocol Version Six Security, Hannah Reinbolt

Missouri S&T’s Peer to Peer

It is no secret that the pool of public internet addresses available with Internet Protocol version Four (IPv4) is gone. (Morphy, 2011) Thus the migration to the more roomy Internet Protocol version Six (IPv6) has begun. This migration is a complex process including different security procedures and updates that require time and knowledge. This paper will dive into scientific writings, with databases like Scopus and IEEE, about various security risks in the IPv6 protocol such as tunneling practices, router issues and issues with Internet Protocol Security (IPsec). This paper will overview security practices to better clarify common vulnerabilities in IPv6. …

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Automated Breast Cancer Diagnosis Using Deep Learning And Region Of Interest Detection (Bc-Droid), Richard Platania, Jian Zhang, Shayan Shams, Kisung Lee, Seungwon Yang, Seung Jong Park Aug 2017

Automated Breast Cancer Diagnosis Using Deep Learning And Region Of Interest Detection (Bc-Droid), Richard Platania, Jian Zhang, Shayan Shams, Kisung Lee, Seungwon Yang, Seung Jong Park

Computer Science Faculty Research & Creative Works

Detection of suspicious regions in mammogram images and the subsequent diagnosis of these regions remains a challenging problem in the medical world. There still exists an alarming rate of misdiagnosis of breast cancer. This results in both over treatment through incorrect positive diagnosis of cancer and under treatment through overlooked cancerous masses. Convolutional neural networks have shown strong applicability to various image datasets, enabling detailed features to be learned from the data and, as a result, the ability to classify these images at extremely low error rates. In order to overcome the difficulty in diagnosing breast cancer from mammogram images, …

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Quantum Oscillations In The Anomalous Spin Density Wave State Of Feas, Daniel J. Campbell, Chris Eckberg, Kefeng Wang, Limin Wang, Halyna Hodovanets, Dave Graf, David Parker, Johnpierre Paglione Aug 2017

Quantum Oscillations In The Anomalous Spin Density Wave State Of Feas, Daniel J. Campbell, Chris Eckberg, Kefeng Wang, Limin Wang, Halyna Hodovanets, Dave Graf, David Parker, Johnpierre Paglione

Physics Faculty Research & Creative Works

Quantum oscillations in the binary antiferromagnetic metal FeAs are presented and compared to theoretical predictions for the electronic band structure in the anomalous spin density wave state of this material. Demonstrating a method for growing single crystals out of Bi flux, we utilize the highest quality FeAs to perform torque magnetometry experiments up to 35 T, using rotations of field angle in two planes to provide evidence for one electron and one hole band in the magnetically ordered state. The resulting picture agrees with previous experimental evidence for multiple carriers at low temperatures, but the exact Fermi surface shape differs …

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A Mathematical Model And Numerical Simulations Of Redox Electrochemical Systems With Mhd And Natural Convection, Kakkattukuzhy M. Isaac, Fangping Yuan Aug 2017

A Mathematical Model And Numerical Simulations Of Redox Electrochemical Systems With Mhd And Natural Convection, Kakkattukuzhy M. Isaac, Fangping Yuan

Collaborative Research: Actively Controllable Microfluidics with Film-Confined Redox-Magnetohydrodynamics -- Video and Data

A comprehensive mathematical model for redox electrochemical systems with magnetohydrodynamics (MHD) and natural convection are presented. The model is based on density changes in isothermal systems that accompany redox reaction at the electrode due to supporting electrolyte ions migrating into and out of the diffusion layer to satisfy electroneutrality. Numerical simulations have been performed for an axisymmetric, milli-electrode electrochemical cell with gravity directed along the axis in both directions to investigate the effect of the electrode orientation with respect to gravity. Results show that natural convection is significant in both cases, with the maximum velocity being an order of magnitude …

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Natural & Unnatural-Parity Contributions In Electron-Impact Ionization Of Laser-Aligned Atoms, Andrew James Murray, James Colgan, Don H. Madison, Matthew Harvey, Ahmad Sakaamini, James Pursehouse, Kate Nixon, Al Stauffer Aug 2017

Natural & Unnatural-Parity Contributions In Electron-Impact Ionization Of Laser-Aligned Atoms, Andrew James Murray, James Colgan, Don H. Madison, Matthew Harvey, Ahmad Sakaamini, James Pursehouse, Kate Nixon, Al Stauffer

Physics Faculty Research & Creative Works

Differential cross section measurements from laser-aligned Mg atoms are compared to theoretical calculations using both time dependent and time-independent formalisms. It is found that both natural and unnatural parity contributions to the calculated cross sections are required to emulate the data when the state is aligned out of the scattering plane.

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Bounding The Moment Deficit Rate On Crustal Faults Using Geodetic Data: Methods, Jeremy Maurer, Paul Segall, Andrew M. Bradley Aug 2017

Bounding The Moment Deficit Rate On Crustal Faults Using Geodetic Data: Methods, Jeremy Maurer, Paul Segall, Andrew M. Bradley

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The geodetically derived interseismic moment deficit rate (MDR) provides a first-order constraint on earthquake potential and can play an important role in seismic hazard assessment, but quantifying uncertainty in MDR is a challenging problem that has not been fully addressed. We establish criteria for reliable MDR estimators, evaluate existing methods for determining the probability density of MDR, and propose and evaluate new methods. Geodetic measurements moderately far from the fault provide tighter constraints on MDR than those nearby. Previously used methods can fail catastrophically under predictable circumstances. The bootstrap method works well with strong data constraints on MDR, but can …

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Gaslight: A Comprehensive Fuzzing Architecture For Memory Forensics Frameworks, Andrew Case, Arghya Kusum Das, Seung Jong Park, J. (Ram) Ramanujam, Golden G. Richard Aug 2017

Gaslight: A Comprehensive Fuzzing Architecture For Memory Forensics Frameworks, Andrew Case, Arghya Kusum Das, Seung Jong Park, J. (Ram) Ramanujam, Golden G. Richard

Computer Science Faculty Research & Creative Works

Memory forensics is now a standard component of digital forensic investigations and incident response handling, since memory forensic techniques are quite effective in uncovering artifacts that might be missed by traditional storage forensics or live analysis techniques. Because of the crucial role that memory forensics plays in investigations and because of the increasing use of automation of memory forensics techniques, it is imperative that these tools be resilient to memory smear and deliberate tampering. Without robust algorithms, malware may go undetected, frameworks may crash when attempting to process memory samples, and automation of memory forensics techniques is difficult. In this …

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Theory Of Retrieving Orientation-Resolved Molecular Information Using Time-Domain Rotational Coherence Spectroscopy, Xu Wang, Anh-Thu Le, Zhaoyan Zhou, Hui Wei, C. D. Lin Aug 2017

Theory Of Retrieving Orientation-Resolved Molecular Information Using Time-Domain Rotational Coherence Spectroscopy, Xu Wang, Anh-Thu Le, Zhaoyan Zhou, Hui Wei, C. D. Lin

Physics Faculty Research & Creative Works

We provide a unified theoretical framework for recently emerging experiments that retrieve fixed-in-space molecular information through time-domain rotational coherence spectroscopy. Unlike a previous approach by Makhija et al. (V. Makhija, arXiv:1611.06476), our method can be applied to the retrieval of both real-valued (e.g., ionization yield) and complex-valued (e.g., induced dipole moment) molecular response information. It is also a direct retrieval method without using iterations. We also demonstrate that experimental parameters, such as the fluence of the aligning laser pulse and the rotational temperature of the molecular ensemble, can be quite accurately determined using a statistical method.

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