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Articles 1 - 18 of 18
Full-Text Articles in Physical Sciences and Mathematics
Modeling And Simulation Of Pressure Waves Generated By Nano-Thermite Reactions, Karen S. Martirosyan, Maxim Zyskin, Charles M. Jenkins, Yasuyuki Horie
Modeling And Simulation Of Pressure Waves Generated By Nano-Thermite Reactions, Karen S. Martirosyan, Maxim Zyskin, Charles M. Jenkins, Yasuyuki Horie
Physics and Astronomy Faculty Publications and Presentations
This paper reports the modeling of pressure waves from the explosive reaction of nano-thermites consisting of mixtures of nanosized aluminum and oxidizer granules. Such nanostructured thermites have higher energy density (up to 26 kJ/cm3) and can generate a transient pressure pulse four times larger than that from trinitrotoluene (TNT) based on volume equivalence. A plausible explanation for the high pressure generation is that the reaction times are much shorter than the time for a shock wave to propagate away from the reagents region so that all the reaction energy is dumped into the gaseous products almost instantaneously and thereby a …
The Critical Coupling Likelihood Method: A New Approach For Seamless Integration Of Environmental And Operating Conditions Of Gravitational Wave Detectors Into Gravitational Wave Searches, Cesar A. Costa, Cristina V. Torres
The Critical Coupling Likelihood Method: A New Approach For Seamless Integration Of Environmental And Operating Conditions Of Gravitational Wave Detectors Into Gravitational Wave Searches, Cesar A. Costa, Cristina V. Torres
Physics and Astronomy Faculty Publications and Presentations
Any search effort for gravitational waves (GWs) using interferometric detectors like LIGO needs to be able to identify if and when noise couples into the detector’s output signal. The critical coupling likelihood (CCL) method has been developed to characterize potential noise coupling and in the future aid GW search efforts. By testing two hypotheses about pairs of channels, CCL is able to identify undesirable coupled instrumental noise from potential GW candidates. Our preliminary results show that CCL can associate up to ∼80% of observed artifacts with SNR ⩾ 8 with local noise sources, while reducing the duty cycle of the …
Fourier Transform Infrared Spectroscopy And Wide-Angle X-Ray Scattering: Investigations On Polypropylene-Vapor-Grown Carbon Nanofiber Composites, Mircea Chipara, John Hamilton, Alin Cristian Chipara, Tom George, Dorina M. Chipara, Elamin Ibrahim, Karen Lozano, David J. Sellmyer
Fourier Transform Infrared Spectroscopy And Wide-Angle X-Ray Scattering: Investigations On Polypropylene-Vapor-Grown Carbon Nanofiber Composites, Mircea Chipara, John Hamilton, Alin Cristian Chipara, Tom George, Dorina M. Chipara, Elamin Ibrahim, Karen Lozano, David J. Sellmyer
Physics and Astronomy Faculty Publications and Presentations
Fourier transform infrared (FTIR) spectroscopy and wide-angle X-ray scattering (WAXS) investigations of isotactic polypropylene (iPP)-vapor-grown carbon nanofiber (VGCNF) composites containing various amounts of VGCNFs ranging between 0 and 20 wt %. are reported. The FTIR investigations were focused on the regularity bands of iPP. The FTIR data indicated a drop in the isotacticity index as the concentration of nanofibers was increased; this suggested a decrease in the crystallinity. WAXS measurements revealed a dominating α 1 phase, with a small admixture of γ phase or mesophase. The loading of the polymeric matrix with carbon nanofibers (CNFs) did not induce significant changes …
Nanoenergetic Composite Based On I2o5/Al For Biological Agent Defeat, Mkhitar Hobosyan, Alexander V. Kazanksy, Karen S. Martirosyan
Nanoenergetic Composite Based On I2o5/Al For Biological Agent Defeat, Mkhitar Hobosyan, Alexander V. Kazanksy, Karen S. Martirosyan
Physics and Astronomy Faculty Publications and Presentations
The risk of bioterrorism events involving the intentional airborne release of contagious agents has led to development of new approaches for bio agent defeat technologies both indoors and outdoors. This report describes nanoenergetic gas generators (NGG) system that exhibit long term stability and superior release of biocidal substances for destruction of pathogenic bacteria. The effect of iodine vaporization on destroying of Escherichia coli (E-coli, HB101 K-12 strain) by using expressing Green Fluorescent Protein (GFP) was investigated. HB101 K-12 has been genetically modified to prevent its growth unless grown on an enriched medium. To obtain quantitative data we used pGLO transformation …
Synthesis And Upconversion Spectroscopy Of Yb Er Doped M2o2s (M = La, Gd, Y) Phosphors, G. A. Kumar, Madhab Pokhrel, Dhiraj K. Sardar, Alejandrina Martinez
Synthesis And Upconversion Spectroscopy Of Yb Er Doped M2o2s (M = La, Gd, Y) Phosphors, G. A. Kumar, Madhab Pokhrel, Dhiraj K. Sardar, Alejandrina Martinez
Physics and Astronomy Faculty Publications and Presentations
Yb and Er doped M2O2S (M = Y, Gd, La) phosphor was synthesized by solid state flux fusion method and their up conversion spectral properties were studied as a function different Yb concentrations. The solid state flux fusion results in well crystallized hexagonal shaped phosphor particles of average size 4–6 μm. Upconversion spectral studies shows that all the compositions are stronger in green emission with the green emission intensity 1.7 times than the red in composition Gd2O2S:Yb(8)Er(1), Y2O2S:Yb(9)Er(1), La2O2S:Yb(3)Er(7) (All mol%). The internal upconversion efficiency for the green emission bands was calculated to be 74, 62, 100% respectively in …
In An Expanding Universe, What Doesn’T Expand?, Richard H. Price, Joseph D. Romano
In An Expanding Universe, What Doesn’T Expand?, Richard H. Price, Joseph D. Romano
Physics and Astronomy Faculty Publications and Presentations
The expansion of the universe is often viewed as a uniform stretching of space that would affect compact objects such as atoms and stars, as well as the separation of galaxies. One usually hears that bound systems do not take part in the general expansion, but a much more subtle question is whether bound systems expand partially. In this paper, a definitive answer is given for a very simple system: a classical “atom” bound by electrical attraction. With a mathematical description appropriate for undergraduate physics majors, we show that this bound system either completely follows the cosmological expansion, or, after …
The Creation And Propagation Of Radiation: Fields Inside And Outside Of Sources, Stanislaw Olbert, John Belcher, Richard H. Price
The Creation And Propagation Of Radiation: Fields Inside And Outside Of Sources, Stanislaw Olbert, John Belcher, Richard H. Price
Physics and Astronomy Faculty Publications and Presentations
We present an algorithm for computing the electromagnetic fields due to currents inside and outside of finite sources with a high degree of spatial symmetry for arbitrary time-dependent currents. The solutions for these fields do not involve the time derivatives of the currents but involve only the currents and their time integrals. We give solutions for moving planar sheets of charge, and a rotating spherical shell carrying a uniform charge density. We show that the general solutions reduce to the standard expressions for magnetic dipole radiation for slow time variations of the currents. If the currents are turned on very …
Hysteresis And Relaxation In Granular Permanent Magnets, Ralph Skomski, B. Balamurugan, Tom A. George, Mircea Chipara, Xiao-Hui Wei, Jeff E. Shield, D. J. Sellmyer
Hysteresis And Relaxation In Granular Permanent Magnets, Ralph Skomski, B. Balamurugan, Tom A. George, Mircea Chipara, Xiao-Hui Wei, Jeff E. Shield, D. J. Sellmyer
Physics and Astronomy Faculty Publications and Presentations
Some nontrivial aspects of the magnetic and structural characterization of hard-magnetic nanoparticles are investigated. Dilute ensembles are well-described by mean-field theory, although there is an asymmetry between exchange and magnetostatic interaction fields. Corrections to the mean-field approximation are caused by cooperative effects and have the character of Onsager reaction fields, which are much stronger in micromagnetism than in atomic-scale magnetism. The slow dynamics of zero-field-cooled (ZFC) magnetization curves is strongly affected by the particles0 magnetic anisotropy, which reduces the corresponding energy-barrier height from 25 to 19.1 kBT.
Thermosensitive Magnetic Nanoparticles For Self-Controlled Hyperthermia Cancer Treatment, Karen S. Martirosyan
Thermosensitive Magnetic Nanoparticles For Self-Controlled Hyperthermia Cancer Treatment, Karen S. Martirosyan
Physics and Astronomy Faculty Publications and Presentations
Magnetic nanoparticles show remarkable phenomena such as superparamagnetism, high field irreversibility and high saturation magnetization [1]. The study of magnetic nanoparticles has been a very active research field due to many important applications such as drug delivery, imaging and hyperthermia cancer treatment [2]. Hyperthermia has been used for many years to treat a wide variety of tumors in patients and used as well as an adjunct to cancer radiotherapy or chemotherapy [3,4]. Its use is based on the fact that tumor cells are more sensitive to temperature in the range of 42–45°C (which yields necrosis, coagulation, or carbonization) than normal …
Exceptional-Point Dynamics In Photonic Honeycomb Lattices With Pt Symmetry, Hamidreza Ramezani, Tsampikos Kottos, Vassilios Kovanis, Demetrios N. Christodoulides
Exceptional-Point Dynamics In Photonic Honeycomb Lattices With Pt Symmetry, Hamidreza Ramezani, Tsampikos Kottos, Vassilios Kovanis, Demetrios N. Christodoulides
Physics and Astronomy Faculty Publications and Presentations
We theoretically investigate the flow of electromagnetic waves in complex honeycomb photonic lattices with local PT symmetries. Such PT structure is introduced via a judicious arrangement of gain and loss across the honeycomb lattice, characterized by a gain and loss parameter γ. We found a class of conical diffraction phenomena where the formed cone is brighter and travels along the lattice with a transverse speed proportional to √γ.
2.1Μm Emission Spectral Properties Of Tm And Ho Doped Transparent Yag Ceramic, G. A. Kumar, Madhab Pokhrel
2.1Μm Emission Spectral Properties Of Tm And Ho Doped Transparent Yag Ceramic, G. A. Kumar, Madhab Pokhrel
Physics and Astronomy Faculty Publications and Presentations
Highly transparent Tm:Ho:YAG transparent ceramics were prepared using advanced ceramic technology and their spectroscopic properties were studied for infrared laser applications. Following the Judd-Ofelt procedure several spectroscopic properties such as the radiative transition probability (Arad), radiative decay time (τrad) and fluorescence branching ratio (β) are quantitatively obtained from the absorption spectrum. The absorption and emission cross sections corresponding to the 5I7 → 5I8 transition of Ho3+ at 2.1 μm have been evaluated following Mc Cumber theory and found that the obtained emission spectrum very well correlates to the simulated emission spectral data. The optical gain spectrum spread …
Search For Gravitational Waves From Low Mass Compact Binary Coalescence In Ligo’S Sixth Science Run And Virgo’S Science Runs 2 And 3, J. Abadie, B. P. Abbott, Matthew Benacquista, R. Biswas, Teviet Creighton, H. Daveloza, Mario C. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano, Robert Stone, A. S. Stroeer
Search For Gravitational Waves From Low Mass Compact Binary Coalescence In Ligo’S Sixth Science Run And Virgo’S Science Runs 2 And 3, J. Abadie, B. P. Abbott, Matthew Benacquista, R. Biswas, Teviet Creighton, H. Daveloza, Mario C. Diaz, R. Grosso, Soumya Mohanty, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano, Robert Stone, A. S. Stroeer
Physics and Astronomy Faculty Publications and Presentations
We report on a search for gravitational waves from coalescing compact binaries using LIGO and Virgo observations between July 7, 2009, and October 20, 2010. We searched for signals from binaries with total mass between 2 and 25M⊙; this includes binary neutron stars, binary black holes, and binaries consisting of a black hole and neutron star. The detectors were sensitive to systems up to 40 Mpc distant for binary neutron stars, and further for higher mass systems. No gravitational-wave signals were detected. We report upper limits on the rate of compact binary coalescence as a function of total mass, including …
On The Synthesis And Physical Properties Of Iron Doped Sno2 Nanoparticles, X. Wei, R. Georgescu, N. Ali, I. Morjan, T. A. George, F. Dumitrache, R. Birjega, Mircea Chipara
On The Synthesis And Physical Properties Of Iron Doped Sno2 Nanoparticles, X. Wei, R. Georgescu, N. Ali, I. Morjan, T. A. George, F. Dumitrache, R. Birjega, Mircea Chipara
Physics and Astronomy Faculty Publications and Presentations
The synthesis of iron doped tin oxide by pulsed laser pyrolysis is reported. The as obtained nanoparticles have a dominant SnO2 phase (as revealed by Wide Angle X-ray Scattering), with particles of the order of 10 nm. The doping with iron or iron oxide triggers magnetic properties as confirmed by SQUID experiments. EDX measurements supported the presence of Fe while Wide Angle X-ray Scattering failed to sense any iron or iron-oxide phase. It is concluded that Fe is well dispersed within the tin-oxide nanoparticles. The coercitive field has a complex dependence on the Fe/Sn content suggesting that the magnetization is …
Tackling Gravity Wave Confusion Noise With Template Optimizers, A. S. Stroeer, Matthew Benacquista
Tackling Gravity Wave Confusion Noise With Template Optimizers, A. S. Stroeer, Matthew Benacquista
Physics and Astronomy Faculty Publications and Presentations
The Mock LISA Data Challenge 4.0 simulated the joint two-year recording of gravitational wave signals from mergers of spinning black holes, extreme mass ratio inspirals, Galactic white dwarf binaries, bursts from cosmic strings, and a stochastic background—all over LISA instrument noise. We analysed this data using a global multi-start box and bound optimization scheme, incorporating multi-dimensional Nelder Mead simplex 2 optimization. Our scheme identified 2658 binaries. Of these, 2246 were found to systematically decompose the power in a strong spinning black hole merger into a "white dwarf binary transform". The remaining 416 binaries were identified with a false alarm rate …
Controlling Calibration Errors In Gravitational-Wave Detectors By Precise Location Of Calibration Forces, H. Daveloza, M Afrin Badhan, Mario C. Diaz, K. Kawabe, P. N. Konverski, M. Landry, R. L. Savage
Controlling Calibration Errors In Gravitational-Wave Detectors By Precise Location Of Calibration Forces, H. Daveloza, M Afrin Badhan, Mario C. Diaz, K. Kawabe, P. N. Konverski, M. Landry, R. L. Savage
Physics and Astronomy Faculty Publications and Presentations
We present results of finite element analysis simulations which could lead to more accurate calibration of interferometric gravitational wave detectors. Calibration and actuation forces applied to the interferometer test masses cause elastic deformation, inducing errors in the calibration. These errors increase with actuation frequency, and can be greater than 50% at frequencies above a few kilohertz. We show that they can be reduced significantly by optimizing the position at which the forces are applied. The Advanced LIGO [1] photon calibrators use a two-beam configuration to reduce the impact of local deformations of the test mass surface. The position of the …
The Characterization Of Virgo Data And Its Impact On Gravitational-Wave Searches, J. Aasi, J. Abadie, Matthew Benacquista, R. Biswas, G. Cagnoli, Teviet Creighton, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, M. E. Normandin, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano, Robert Stone, A. S. Stroeer, Cristina V. Torres
The Characterization Of Virgo Data And Its Impact On Gravitational-Wave Searches, J. Aasi, J. Abadie, Matthew Benacquista, R. Biswas, G. Cagnoli, Teviet Creighton, H. Daveloza, Mario C. Diaz, S. R. Morriss, Soma Mukherjee, M. E. Normandin, Volker Quetschke, Malik Rakhmanov, Joseph D. Romano, Robert Stone, A. S. Stroeer, Cristina V. Torres
Physics and Astronomy Faculty Publications and Presentations
Between 2007 and 2010 Virgo collected data in coincidence with the LIGO and GEO gravitational-wave (GW) detectors. These data have been searched for GWs emitted by cataclysmic phenomena in the universe, by non-axisymmetric rotating neutron stars or from a stochastic background in the frequency band of the detectors. The sensitivity of GW searches is limited by noise produced by the detector or its environment. It is therefore crucial to characterize the various noise sources in a GW detector. This paper reviews the Virgo detector noise sources, noise propagation, and conversion mechanisms which were identified in the three first Virgo observing …
Thermal Effects In The Input Optics Of The Enhanced Laser Interferometer Gravitational-Wave Observatory Interferometers, K. L. Dooley, M. A. Arain, D. Fieldbaum, Volker Quetschke
Thermal Effects In The Input Optics Of The Enhanced Laser Interferometer Gravitational-Wave Observatory Interferometers, K. L. Dooley, M. A. Arain, D. Fieldbaum, Volker Quetschke
Physics and Astronomy Faculty Publications and Presentations
We present the design and performance of the LIGO Input Optics subsystem as implemented for the sixth science run of the LIGO interferometers. The Initial LIGO Input Optics experienced thermal side effects when operating with 7 W input power. We designed, built, and implemented improved versions of the Input Optics for Enhanced LIGO, an incremental upgrade to the Initial LIGO interferometers, designed to run with 30 W input power. At four times the power of Initial LIGO, the Enhanced LIGO Input Optics demonstrated improved performance including better optical isolation, less thermal drift, minimal thermal lensing, and higher optical efficiency. The …
Screen-Printing Of Ferrite Magnetic Nanoparticles Produced By Carbon Combustion Synthesis Of Oxides, Karen S. Martirosyan, Gamage Dannangoda, Eduard Galstyan, Dmitri Litvinov
Screen-Printing Of Ferrite Magnetic Nanoparticles Produced By Carbon Combustion Synthesis Of Oxides, Karen S. Martirosyan, Gamage Dannangoda, Eduard Galstyan, Dmitri Litvinov
Physics and Astronomy Faculty Publications and Presentations
The feasibility of screen-printing process of hard ferrite magnetic nanoparticles produced by carbon combustion synthesis of oxides (CCSO) is investigated. In CCSO, the exothermic oxidation of carbon generates a smolder thermal reaction wave that propagates through the solid reactant mixture converting it to the desired oxides. The complete conversion of hexaferrites occurs using reactant mixtures containing 11 wt. % of carbon. The BaFe12O19 and SrFe12O19 hexaferrites had hard magnetic properties with coercivity of 3 and 4.5 kOe, respectively. It was shown that the synthesized nanoparticles could be used to fabricate permanent magnet structures by consolidating them using screen-printing techniques.