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Articles 91 - 120 of 120
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Nonlinear Ionospheric Responses To Large-Amplitude Infrasonic-Acoustic Waves Generated By Undersea Earthquakes, M. D. Zettergren, J. B. Snively, A. Komjathy, O. P. Verkhoglyadova
Nonlinear Ionospheric Responses To Large-Amplitude Infrasonic-Acoustic Waves Generated By Undersea Earthquakes, M. D. Zettergren, J. B. Snively, A. Komjathy, O. P. Verkhoglyadova
Publications
Numerical models of ionospheric coupling with the neutral atmosphere are used to investigate perturbations of plasma density, vertically integrated total electron content (TEC), neutral velocity, and neutral temperature associated with large-amplitude acoustic waves generated by the initial ocean surface displacements from strong undersea earthquakes. A simplified source model for the 2011 Tohoku earthquake is constructed from estimates of initial ocean surface responses to approximate the vertical motions over realistic spatial and temporal scales. Resulting TEC perturbations from modeling case studies appear consistent with observational data, reproducing pronounced TEC depletions which are shown to be a consequence of the impacts of …
Turning Contention Into Collaboration: Engaging Power, Trust, And Learning In Collaborative Networks, Vanessa Levesque, Aram J K Calhoun, Kathleen P. Bell, Teresa R. Johnson
Turning Contention Into Collaboration: Engaging Power, Trust, And Learning In Collaborative Networks, Vanessa Levesque, Aram J K Calhoun, Kathleen P. Bell, Teresa R. Johnson
Publications
Given the complexity and multiplicity of goals in natural resource governance, it is not surprising that policy debates are often characterized by contention and competition. Yet at times adversaries join together to collaborate to find creative solutions not easily achieved in polarizing forums. We employed qualitative interviews and a quantitative network analysis to investigate a collaborative network that formed to develop a resolution to a challenging natural resource management problem, the conservation of vernal pools. We found that power had become distributed among members, trust had formed across core interests, and social learning had resulted in shared understanding and joint …
Numerical Modeling Of A Multiscale Gravity Wave Event And Its Airglow Signatures Over Mount Cook, New Zealand, During The Deepwave Campaign, C. J. Heale, K. Bossert, J. B. Snively, D. C. Fritts, P. -D. Pautet, M. J. Taylor
Numerical Modeling Of A Multiscale Gravity Wave Event And Its Airglow Signatures Over Mount Cook, New Zealand, During The Deepwave Campaign, C. J. Heale, K. Bossert, J. B. Snively, D. C. Fritts, P. -D. Pautet, M. J. Taylor
Publications
A 2-D nonlinear compressible model is used to simulate a large-amplitude, multiscale mountain wave event over Mount Cook, NZ, observed as part of the Deep Propagating Gravity Wave Experiment (DEEPWAVE) campaign and to investigate its observable signatures in the hydroxyl (OH) layer. The campaign observed the presence of a �x = 200 km mountain wave as part of the 22nd research flight with amplitudes of >20 K in the upper stratosphere that decayed rapidly at airglow heights. Advanced Mesospheric Temperature Mapper (AMTM) showed the presence of small-scale (25–28 km) waves within the warm phase of the large mountain wave. The …
Application Of An Rbf Blending Interpolation Method To Problems With Shocks, Michael Harris, Eduardo Divo, Alain J. Kassab
Application Of An Rbf Blending Interpolation Method To Problems With Shocks, Michael Harris, Eduardo Divo, Alain J. Kassab
Publications
Radial basis functions (RBF) have become an area of research in recent years, especially in the use of solving partial differential equations (PDE). Radial basis functions have an impressive capability in interpolating scattered data, even for data with discontinuities. Although, for infinitely smooth radial basis functions such as the multi-quadrics and inverse multi-quadrics, the shape parameter must be chosen properly to obtain accurate approximations while avoiding ill-conditioning of the interpolating matrices. The optimum shape parameter can vary depending on the field, such as in locations of sharp gradients or shocks. Typically, the shape parameter is chosen to maintain a high …
Wiggle 3d Displays Of Weather Data, Frederick R. Mosher
Wiggle 3d Displays Of Weather Data, Frederick R. Mosher
Publications
Weather is a time varying 3-dimensional phenomena, but the displays of weather data are inherently 2-dimensional. Since weather phenomena at one level can impact the weather at another level, it would be desirable to view weather on a 3D volume type of display. Initially weather displays were on paper and currently weather information is displayed on computer screens. The human mind can interpret 3D volume information in a number of ways. Having two eyes, the brain can detect the parallax differences between the images for the left eye being slightly different from the right eye. Objects that are closer to …
Hubble Parameter Measurement Constraints On The Redshift Of The Deceleration-Acceleration Transition, Dynamical Dark Energy, And Space Curvature, Muhammad O. Farooq, Foram R. Madiyar, Sara Crandall, Bharat Ratra
Hubble Parameter Measurement Constraints On The Redshift Of The Deceleration-Acceleration Transition, Dynamical Dark Energy, And Space Curvature, Muhammad O. Farooq, Foram R. Madiyar, Sara Crandall, Bharat Ratra
Publications
We compile an updated list of 38 measurements of the Hubble parameter H(z) between redshifts 0.07 ≤ z ≤ 2.36 and use them to place constraints on model parameters of constant and time-varying dark energy cosmological models, both spatially flat and curved. We use five models to measure the redshift of the cosmological deceleration-acceleration transition, zda, from these H(z) data. Within the error bars, the measured zda are insensitive to the model used, depending only on the value assumed for the Hubble constant H0. The weighted mean of our measurements is zda = 0.72 ± 0.05 (0.84 ± 0.03) for …
Numerical Simulation Of Acoustic Emission During Crack Growth In 3-Point Bending Test, Mihhail Berezovski, Arkadi Berezovski
Numerical Simulation Of Acoustic Emission During Crack Growth In 3-Point Bending Test, Mihhail Berezovski, Arkadi Berezovski
Publications
Numerical simulation of acoustic emission by crack propagation in 3-point bending tests is performed to investigate how the interaction of elastic waves generates a detectable signal. It is shown that the use of a kinetic relation for the crack tip velocity combined with a simple crack growth criterion provides the formation of waveforms similar to those observed in experiments.
Real Data Is Messy... And Manageable, Beverly Wood, Carl Clark
Real Data Is Messy... And Manageable, Beverly Wood, Carl Clark
Publications
Using real data in an introductory statistics course is a delicate balance between reality and manageability. The internet is awash with data that is useful for students to answer questions of interest to them but it is not always formatted as neatly as textbook data. The ASA's recently endorsed GAISE College Report 2016 points to the plausibility of considering multivariable thinking even if only at a rudimentary level. With both messy and multivariable data in mind, we present some activities/projects and sources for data to give introductory students the opportunity to engage with real data.
Anisotropic Fluid Modeling Of Ionospheric Upflow: Effects Of Low‐Altitude Anisotropy And Thermospheric Winds, M. R. Burleigh, M. Zettergren
Anisotropic Fluid Modeling Of Ionospheric Upflow: Effects Of Low‐Altitude Anisotropy And Thermospheric Winds, M. R. Burleigh, M. Zettergren
Publications
A new anisotropic fluid model is developed to describe ionospheric upflow responses to magnetospheric forcing by electric fields and broadband ELF waves at altitudes of 90–2500 km. This model is based on a bi‐Maxwellian ion distribution and solves time‐dependent, nonlinear equations of conservation of mass, momentum, parallel energy, and perpendicular energy for six ion species important to E, F, and topside ionospheric regions. It includes chemical and collisional interactions with the neutral atmosphere, photoionization, and electron impact ionization. This model is used to examine differences between isotropic and anisotropic descriptions of ionospheric upflow driven by DC electric fields, …
Trustworthiness Requirements For Manufacturing Cyber-Physical Systems, Radu F. Babiceanu, Remzi Seker
Trustworthiness Requirements For Manufacturing Cyber-Physical Systems, Radu F. Babiceanu, Remzi Seker
Publications
Distributed manufacturing operations include cyber-physical systems vulnerable to cyber-attacks. Long time not considered a priority, cybersecurity jumped to the forefront of manufacturing concerns due to the need to network together legacy, newer equipment, and entire operation centers. This paper proposes trustworthiness solutions for integrated manufacturing physical-cyber worlds, where trustworthiness is defined to complement system dependability requirements with cybersecurity requirements, such that the resulting manufacturing cyber-physical system delivers services that can justifiably be trusted. Acknowledging the inevitability of cyber-attacks, the paper models the cybersecurity component using the resilient systems framework, where system resilience is viewed as preservation of a required state …
Delphiforce, A Tool For Electrostatic Force Calculations: Applications To Macromolecular Binding, Lin Li, Arghya Chakravorty, Emil Alexov
Delphiforce, A Tool For Electrostatic Force Calculations: Applications To Macromolecular Binding, Lin Li, Arghya Chakravorty, Emil Alexov
Publications
Long-range electrostatic forces play an important role in molecular biology, particularly in macromolecular interactions. However, calculating the electrostatic forces for irregularly shaped molecules immersed in water is a difficult task. Here, we report a new tool, DelPhiForce, which is a tool in the DelPhi package that calculates and visualizes the electrostatic forces in biomolecular systems. In parallel, the DelPhi algorithm for modeling electrostatic potential at user-defined positions has been enhanced to include triquadratic and tricubic interpolation methods. The tricubic interpolation method has been tested against analytical solutions and it has been demonstrated that the corresponding errors are negligibly small at …
Green Building Business Is Booming, Richard Snow, Mary Snow
Green Building Business Is Booming, Richard Snow, Mary Snow
Publications
Shelter is one of life’s basic necessities. However, according to the U.S. Department of Energy, residential and commercial buildings account for nearly 40% of the total carbon dioxide (CO2) released in the United States annually [1]. The percentage is even higher in China, which leads the world in CO2 emissions from buildings. Most of this CO2 comes from burning fossil fuels to provide the energy necessary to cool, heat, and light homes, office buildings, and retail space. CO2 emissions from residential and commercials buildings are forecast to increase more than emissions from any other sector over the next 25 years. …
Gyrochronology Of Wide Binaries In The Kepler K2 Fields, Alexander Stone-Martinez, Gustavo Villarroel, Patrice Majewski, Tomomi Otani, Terry Oswalt, Andrew Mcnaughton
Gyrochronology Of Wide Binaries In The Kepler K2 Fields, Alexander Stone-Martinez, Gustavo Villarroel, Patrice Majewski, Tomomi Otani, Terry Oswalt, Andrew Mcnaughton
Publications
Gyrochronology is the method of determining a stars age based on its rotation period and mass. A cool main sequence star loses it's angular momentum as it ages, so the rotation rate slows down. Gyrochronology has been tested on star clusters in previous studies and now we are applying the theory to binary stars. Components of a binary should be the same age, so Gyrochronology should return the same age for both stars in binary systems. We examined the rotation periods for 290 wide binary main sequence stars in the Kepler K2 fields. These observations are part of a continuing …
Testing The Stellar Rotation Vs. Age Paradigm Using Wide Binaries In The Kepler & K2 Fields, T. D. Oswalt, T. Otani, A. Stone-Martinez, P. Majewski, D. Buzasi
Testing The Stellar Rotation Vs. Age Paradigm Using Wide Binaries In The Kepler & K2 Fields, T. D. Oswalt, T. Otani, A. Stone-Martinez, P. Majewski, D. Buzasi
Publications
Essential to understanding the history of the Galaxy’s stellar populations, ages are among the most difficult to measure properties of stars. Accurate stellar ages would provide key leverage on problems ranging from the habitability of exoplanets to the Galaxy’s chemical evolution and age. Gyrochronology, the empirical relation between rotation and age, is believed to be among the best current methods of stellar age determination. Using several hundred wide non-interacting binaries identified in the Kepler mission “K2” extended mission fields we are testing this paradigm. Such wide pairs afford a unique opportunity to unravel and calibrate the effects of mass, rotation, …
The Remote Observatories Of The Southeastern Association For Research In Astronomy (Sara), William C. Keel, Terry D. Oswalt, Peter Mack, Gary Henson, Todd Hillwig, Et Al.
The Remote Observatories Of The Southeastern Association For Research In Astronomy (Sara), William C. Keel, Terry D. Oswalt, Peter Mack, Gary Henson, Todd Hillwig, Et Al.
Publications
We describe the remote facilities operated by the Southeastern Association for Research in Astronomy (SARA) , a consortium of colleges and universities in the US partnered with Lowell Observatory, the Chilean National Telescope Allocation Committee, and the Instituto de Astrofísica de Canarias. SARA observatories comprise a 0.96 m telescope at Kitt Peak, Arizona; one of 0.6 m aperture on Cerro Tololo, Chile; and the 1 m Jacobus Kapteyn Telescope at the Roque de los Muchachos, La Palma, Spain. All are operated using standard VNC or Radmin protocols communicating with on-site PCs. Remote operation offers considerable flexibility in scheduling, allowing long-term …
Gyrochronology Of Wide Binaries In The Kepler K2 Campaign 5 Field, Terry D. Oswalt, Derek Buzasi, Tomomi Otani
Gyrochronology Of Wide Binaries In The Kepler K2 Campaign 5 Field, Terry D. Oswalt, Derek Buzasi, Tomomi Otani
Publications
We are determining rotation periods for an ensemble of over 100 wide non-interacting binary stars in the K2 Campaign 5 field that contain two main sequence dwarfs, as well as a smaller sample containing at least one white dwarf component. Observations of such coeval pairs provide the basis for our new investigation of rotation-based age determinations. Such “gyrochronology” ages can achieve a precision that exceeds most other current method of stellar age determination. Here we present a status report on our analysis of the light curves extracted from the K2 Campaign 5 field.
Search For Binaries In The Kepler K2 Fields Using Pulsation Timing Method, Tomomi Otani, Terry Oswalt
Search For Binaries In The Kepler K2 Fields Using Pulsation Timing Method, Tomomi Otani, Terry Oswalt
Publications
Finding orbital solutions of binaries which have small mass ratios (50 days) is challenging using traditional techniques. The radial velocity method is a good way to detect such binary stars, however it requires large telescopes. Therefore, the search for binaries in those regions is still incomplete. For binaries in this regime with at least one component that pulsates, pulsation timing is a better approach. Orbital solutions for such systems can be obtained from the periodic change in pulse arrival times as the star’s reflex motion is manifested by the changing distance along the line of sight. We present a search …
First Performance Results Of A New Field-Widened Spatial Heterodyne Spectrometer For Geocoronal Hα Research, D. D. Gardner, E. J. Mierkiewicz, F. L. Roesler, J. M. Harlander, K. P. Jaehnig, S. M. Nossal, L. M. Haffner
First Performance Results Of A New Field-Widened Spatial Heterodyne Spectrometer For Geocoronal Hα Research, D. D. Gardner, E. J. Mierkiewicz, F. L. Roesler, J. M. Harlander, K. P. Jaehnig, S. M. Nossal, L. M. Haffner
Publications
A new, high-resolution field-widened spatial heterodyne spectrometer (FW-SHS) designed to observe geocoronal Balmer α (Hα, 6563 Å) emission was installed at Pine Bluff Observatory (PBO) near Madison, Wisconsin. FW-SHS observations were compared with an already well-characterized dual-etalon Fabry-Perot Interferometer (PBO FPI) optimized for Hα, also at PBO. The FW-SHS is a robust Fourier transform instrument that combines a large throughput advantage with high spectral resolution and a relatively long spectral baseline (~10 times that of the PBO FPI) in a compact, versatile instrument with no moving parts.Coincident Hα observations by FW-SHS and PBO FPI were obtained over similar integration times, …
Using Journals To Assess Non-Stem Student Learning In Stem Courses: A Case Study In Cybersecurity Education, Gary Kessler, Glenn S. Dardick, Douglas L. Holton
Using Journals To Assess Non-Stem Student Learning In Stem Courses: A Case Study In Cybersecurity Education, Gary Kessler, Glenn S. Dardick, Douglas L. Holton
Publications
Embry-Riddle Aeronautical University offers a minor course of study in cybersecurity as an option in our undergraduate Homeland Security program. Since the students are, by and large, social scientists, the focus of the program is to build hyper-awareness of how cybersecurity integrates within their professional aspirations rather than to provide cybersecurity career-level proficiency. Assessing student learning of the technical aspects cannot be performed using traditional tests, as they would not properly measure what the students are learning in a practical sense. Instead, we employ journals and self-reflection to ask the students to express and demonstrate their learning. Although somewhat harder …
Utilizing The O-C Method To Determine Third-Body Existence In Eclipsing Binary Systems, Patrice Majewski, Tomomi Otani, Terry D. Oswalt
Utilizing The O-C Method To Determine Third-Body Existence In Eclipsing Binary Systems, Patrice Majewski, Tomomi Otani, Terry D. Oswalt
Publications
Previous studies on the subject of eclipsing binaries (EBs) within the Kepler field have been adequately determined the period, distance, and other stellar parameters of these systems (Borkovits, et al. 2015). Additionally, with the use of Observed-minus-Calculated (O-C) plots, variation in the timing of timing of eclipses can be easily detected. The eclipse timing shifts may be caused by dynamical effects or by light-travel time effects (LTTE) caused by the existence of a third body. The following research was conducted on ten binaries within the Kepler “K2” Campaign 5 field whose light curves (LCs) showed evidence of eclipses with periods …
Exploring Myths In Digital Forensics: Separating Science From Ritual, Gary C. Kessler, Gregory H. Carlton
Exploring Myths In Digital Forensics: Separating Science From Ritual, Gary C. Kessler, Gregory H. Carlton
Publications
Digital forensic methodology deviates significantly relative to the methods of other forensic sciences for numerous practical reasons, and it has been largely influenced by factors derived from the inception and evolution of this relatively new and rapidly changing field. Digital forensics methodology was developed more by practitioners in its early days rather than by computer scientists. This led to accepted best practices in the field that may not represent the best or, at least, tested, science. This paper explores some of these differences in the practice and evolution between digital and other forensic sciences, and recommends scientific approaches to apply …
Spatial And Temporal Variability In Mlt Turbulence Inferred From In Situ And Ground-Based Observations During The Wadis-1 Sounding Rocket Campaign, Boris Strelnikov, Arthur Szewczyk, Irina Strelnikova, Ralph Latteck, Gerd Baumgarten, Franz-Josef Lübken, Et. Al.
Spatial And Temporal Variability In Mlt Turbulence Inferred From In Situ And Ground-Based Observations During The Wadis-1 Sounding Rocket Campaign, Boris Strelnikov, Arthur Szewczyk, Irina Strelnikova, Ralph Latteck, Gerd Baumgarten, Franz-Josef Lübken, Et. Al.
Publications
In summer 2013 the WADIS-1 sounding rocket campaign was conducted at the Andøya Space Center (ACS) in northern Norway (69° N, 16° E). Among other things, it addressed the question of the variability in mesosphere/lower thermosphere (MLT) turbulence, both in time and space. A unique feature of the WADIS project was multi-point turbulence sounding applying different measurement techniques including rocket-borne ionization gauges, VHF MAARSY radar, and VHF EISCAT radar near Tromsø. This allowed for horizontal variability to be observed in the turbulence field in the MLT at scales from a few to 100 km. We found that the turbulence dissipation …
Assessing The Efficiency Of Different Sustainable Farming Practices In Reducing The Environmental Impacts Caused By Aquaculture, Rajee Olaganathan, Alicia Tang Kar Mun
Assessing The Efficiency Of Different Sustainable Farming Practices In Reducing The Environmental Impacts Caused By Aquaculture, Rajee Olaganathan, Alicia Tang Kar Mun
Publications
Sustainability of aquaculture is achieved when aquaculture farming systems are capable of preserving the natural resource base and involves an institutional change to the environment by the attainment and continued satisfaction for present and future generations. Sustainable farming practices produce sufficient aquaculture output to satisfy the seafood demand while not burdening the environment more. The potentiality and efficiency of different sustainable aqua farming practices in reducing anthropogenic impacts to the environment by aquaculture are assessed in this paper. Polyculture is mostly adopted by small-scale rural farmers as it requires low entry barrier and help in income diversification. The input of …
Technological Modernization And Its Impact On Agriculture, Fisheries And Fossil Fuel Utilization In The Asia Pacific Countries With Emphasis On Sustainability Perspective, Rajee Olaganathan, Kathleen Quigley
Technological Modernization And Its Impact On Agriculture, Fisheries And Fossil Fuel Utilization In The Asia Pacific Countries With Emphasis On Sustainability Perspective, Rajee Olaganathan, Kathleen Quigley
Publications
Modernization is a process that moves towards efficiency. This affects most of the fields such as agriculture, fisheries, forestry, urban planning, policy, fossil fuel usage, manufacturing, technology, economic growth etc. This process plays a major role in moving forward making things faster, better and basically more efficient. The effects of modernization on all these fields bring about the major changes to aspects such as social, economic and the environment. The level of operation has increased from a domestic level; small family scale business to large commercial levels. As the level of operation increased, the utilization of natural resources increased gradually …
The Basic Physics Of The Binary Black Hole Merger Gw150914, B. P. Abbott, K. Gill, B. Hughey, J. Pratt, M. J. Szczepańczyk, M. Zanolin, Et Al.
The Basic Physics Of The Binary Black Hole Merger Gw150914, B. P. Abbott, K. Gill, B. Hughey, J. Pratt, M. J. Szczepańczyk, M. Zanolin, Et Al.
Publications
The first direct gravitational-wave detection was made by the Advanced Laser Interferometer Gravitational Wave Observatory on September 14, 2015. The GW150914 signal was strong enough to be apparent, without using any waveform model, in the filtered detector strain data. Here, features of the signal visible in the data are analyzed using concepts from Newtonian physics and general relativity, accessible to anyone with a general physics background. The simple analysis presented here is consistent with the fully general-relativistic analyses published elsewhere, in showing that the signal was produced by the inspiral and subsequent merger of two black holes. The black holes …
Information Technology Approaches To Forest Management, Mary Snow, Richard Snow
Information Technology Approaches To Forest Management, Mary Snow, Richard Snow
Publications
The majority of the world’s forests occur where there is a dry season long enough to affect a seasonal change in the forest community. The seasonal forest may include evergreen, semi-deciduous, deciduous trees, or some combination of these. Local differences in soil or other site characteristics often determine which community persists. Since the seasonal forests exist where there is seasonal precipitation, the character of the forest is closely associated with the length of the rainy season. As the length of the rainy season decreases, the density of the canopy decreases. If the global climate system warms and prolonged drought gives …
Success Stories In Knowledge Management Systems, Leila Halawi, Richard Mccarthy, Janine Aronson
Success Stories In Knowledge Management Systems, Leila Halawi, Richard Mccarthy, Janine Aronson
Publications
Historically, information systems have focused on capturing, storing, managing, and reporting explicit knowledge. Organizations today recognize the need to integrate both explicit and tacit knowledge in formal information systems. Knowledge management continues to be a critical strategy for an organization to achieve a sustainable competitive advantage, and consequently succeed in today's knowledge-based economy. Knowledge management systems (KMS) are a class of information systems that manage, store and distribute knowledge. Knowledge management systems have proliferated in practice. In turn, theoretical research on knowledge management and knowledge management systems has proliferated. Knowledge management systems have emerged as powerful sources of competitive advantage. …
O-C Analysis Of The Pulsating Subdwarf B Star Pg 1219 + 534, Tomomi Otani, Terry Oswalt, Alexander Stone-Martinez, Dana Singh, Kenneth Sampson, Aliyah Khan, Austin Seepersad, Caila Deabreu, Adam Moss, Claudia Morello
O-C Analysis Of The Pulsating Subdwarf B Star Pg 1219 + 534, Tomomi Otani, Terry Oswalt, Alexander Stone-Martinez, Dana Singh, Kenneth Sampson, Aliyah Khan, Austin Seepersad, Caila Deabreu, Adam Moss, Claudia Morello
Publications
PG 1219 + 534 (KY Uma) is a subdwarf B pulsating star with multiple periodicities between 120 – 175 s. PG 1219 + 534 was monitored for 90 hours during 2010-1 and 2016 using the 0.9 m SARA-KP telescope at Kitt Peak National Observatory (KPNO) in Arizona and the 0.8m Ortega telescope at Florida Institute of Technology in Melbourne, Florida. So far, the most promising theory for the origin of subdwarf B (sdB) stars is that they result from binary mass transfer near the Helium Flash stage of evolution. The observations of PG 1219 + 534 reported here are part …
Hubble Parameter Measurement Constraints On The Redshift Of The Deceleration-Acceleration Transition, Dynamical Dark Energy, And Space Curvature, Omer Farooq, Foram Ranjeet Madiyar, Sara Crandall, Bharat Ratra
Hubble Parameter Measurement Constraints On The Redshift Of The Deceleration-Acceleration Transition, Dynamical Dark Energy, And Space Curvature, Omer Farooq, Foram Ranjeet Madiyar, Sara Crandall, Bharat Ratra
Publications
We compile an updated list of 38 measurements of the Hubble parameter H(z) between redshifts 0.07 ≤ z ≤ 2.36 and use them to place constraints on model parameters of constant and time-varying dark energy cosmological models, both spatially flat and curved. We use five models to measure the redshift of the cosmological deceleration-acceleration transition, zda, from these H(z) data. Within the error bars, the measured zda are insensitive to the model used, depending only on the value assumed for the Hubble constant H0. The weighted mean of our measurements is zda = 0.72±0.05 (0.84±0.03) for H0 = 68 ± …
Multi-Scale Cardiovascular Flow Analysis By An Integrated Meshless-Lumped Parameter Model, Leonardo A. Bueno, Eduardo A. Divo, Alain J. Kassab
Multi-Scale Cardiovascular Flow Analysis By An Integrated Meshless-Lumped Parameter Model, Leonardo A. Bueno, Eduardo A. Divo, Alain J. Kassab
Publications
A computational tool that integrates a Radial basis function (RBF)-based Meshless solver with a Lumped Parameter model (LPM) is developed to analyze the multi-scale and multi-physics interaction between the cardiovascular flow hemodynamics, the cardiac function, and the peripheral circulation. The Meshless solver is based on localized RBF collocations at scattered data points which allows for automation of the model generation via CAD integration. The time-accurate incompressible flow hemodynamics are addressed via a pressure-velocity correction scheme where the ensuing Poisson equations are accurately and efficiently solved at each time step by a Dual-Reciprocity Boundary Element method (DRBEM) formulation that takes advantage …