247 research outputs found
COUNTER-UXS ENERGY AND OPERATIONAL ANALYSIS
At present, there exists a prioritization of identifying novel and innovative approaches to managing the small Unmanned Aircraft Systems (sUAS) threat. The near-future sUAS threat to U.S. forces and infrastructure indicates that current Counter-UAS (C-UAS) capabilities and tactics, techniques, and procedures (TTPs) need to evolve to pace the threat. An alternative approach utilizes a networked squadron of unmanned aerial vehicles (UAVs) designed for sUAS threat interdiction. This approach leverages high performance and Size, Weight, and Power (SWaP) conformance to create less expensive, but more capable, C-UAS devices to augment existing capabilities.
This capstone report documents efforts to develop C-UAS technologies to reduce energy consumption and collaterally disruptive signal footprint while maintaining operational effectiveness. This project utilized Model Based System Engineering (MBSE) techniques to explore and assess these technologies within a mission context. A Concept of Operations was developed to provide the C-UAS Operational Concept. Operational analysis led to development of operational scenarios to define the System of Systems (SoS) concept, operating conditions, and required system capabilities. Resource architecture was developed to define the functional behaviors and system performance characteristics for C-UAS technologies. Lastly, a modeling and simulation (M&S) tool was developed to evaluate mission scenarios for C-UAS.Outstanding ThesisCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyCivilian, Department of the NavyApproved for public release. Distribution is unlimited
Evolution of density perturbations in a realistic universe
Prompted by the recent more precise determination of the basic cosmological
parameters and growing evidence that the matter-energy content of the universe
is now dominated by dark energy and dark matter we present the general solution
of the equation that describes the evolution of density perturbations in the
linear approximation. It turns out that as in the standard CDM model the
density perturbations grow very slowly during the radiation dominated epoch and
their amplitude increases by a factor of about 4000 in the matter and later
dark energy dominated epoch of expansion of the universe.Comment: 19 pages, 4 figure
"Cosmological" quasiparticle production in harmonically trapped superfluid gases
We show that a variety of cosmologically motivated effective quasiparticle
space-times can be produced in harmonically trapped superfluid Bose and Fermi
gases. We study the analogue of cosmological particle production in these
effective space-times, induced by trapping potentials and coupling constants
possessing an arbitrary time dependence. The WKB probabilities for phonon
creation from the superfluid vacuum are calculated, and an experimental
procedure to detect quasiparticle production by measuring density-density
correlation functions is proposed.Comment: 8 pages, 1 figure; references updated, as published in Physical
Review
Curvature in causal BD-type inflationary cosmology
We study a closed model of the universe filled with viscous fluid and
quintessence matter components in a Brans-Dicke type cosmological model. The
dynamical equations imply that the universe may look like an accelerated flat
Friedmann-Robertson-Walker universe at low redshift. We consider here
dissipative processes which follow a causal thermodynamics. The theory is
applied to viscous fluid inflation, where accepted values for the total entropy
in the observable universe is obtained.Comment: 11 pages, revtex 4. For a festschrift honoring Alberto Garcia. To be
publishen in Gen. Rel. Gra
Influence of Incomplete Fusion Reaction on Complete Fusion Below 10 Mev/ Nucleon Energies
An attempt has been made in the present work to provide an ample opportunity to explore the information about the influence of incomplete fusion (ICF) reaction dynamics on complete fusion in heavy ion induced nuclear reactions. excitation functions for several evaporation residues produced in the interaction of projectile 16O with target 175lu have been measured over the wide projectile energy range ≈ 70-100 MeV. the recoil-catcher activation technique followed by the offline γ-ray spectroscopy has been used for the present measurements. In case of precursor decay, we have made use of Cavinato et al. formulation to calculate the independent cross-section of the identified residues. the measured efs are compared with theoretical predictions of statistical model code PACE-2 and any enhancement in the measured cross-section from theoretical prediction may be due to ICF reaction process. An attempt has been made to estimate the ICf contribution of the cross-section from the measured excitation function data and the dependence of ICf cross-section on projectile energy
Absolute ozone densities in a radio-frequency driven atmospheric pressure plasma using two-beam UV-LED absorption spectroscopy and numerical simulations
International audienceThe efficient generation of reactive oxygen species (ROS) in cold atmospheric pressure plasma jets (APPJs) is an increasingly important topic, e.g. for the treatment of temperature sensitive biological samples in the field of plasma medicine. A 13.56 MHz radio-frequency (rf) driven APPJ device operated with helium feed gas and small admixtures of oxygen (up to 1%), generating a homogeneous glow-mode plasma at low gas temperatures, was investigated. Absolute densities of ozone, one of the most prominent ROS, were measured across the 11 mm wide discharge channel by means of broadband absorption spectroscopy using the Hartley band centred at lambda = 255 nm. A two-beam setup with a reference beam in Mach--Zehnder configuration is employed for improved signal-to-noise ratio allowing high-sensitivity measurements in the investigated single-pass weak-absorbance regime. The results are correlated to gas temperature measurements, deduced from the rotational temperature of the N2 (C 3 {{{\Pi }}}u \to B 3 {{{\Pi }}}g , upsilo = 0 \to 2) optical emission from introduced air impurities. The observed opposing trends of both quantities as a function of rf power input and oxygen admixture are analysed and explained in terms of a zero-dimensional plasma-chemical kinetics simulation. It is found that the gas temperature as well as the densities of O and O2(b{}1{{{Sigma }}}g ) influence the absolute O3 densities when the rf power is varied
Quasi-elastic scattering measurements of the 28Si + 142Nd system at back-angle
The barrier distribution of a system can be extracted from excitation function data obtained either through fusion reaction or through quasi-elastic scattering measurement. In the present work, the quasi-elastic excitation function has precisely been measured at back angle for the 28Si + 142Nd system at energies around the Coulomb barrier and the corresponding experimental barrier distribution has been extracted. The experimental data has been interpreted in the frame work of the coupled channel calculations which include couplings to different possible modes of excitations of the interacting target-projectile combination. The possible effect of the nature of projectile excitations on the derived barrier distribution has been presented
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