Enhanced backscatter of optical beams reflected in turbulent air

Optical beams propagating through air acquire phase distortions from turbulent fluctuations in the refractive index. While these distortions are usually deleterious to propagation, beams reflected in a turbulent medium can undergo a local recovery of spatial coherence and intensity enhancement referred to as enhanced backscatter (EBS). Using a combination of lab-scale experiments and simulations, we investigate the EBS of optical beams reflected from corner cubes and rough surfaces, and identify the regimes in which EBS is most distinctly observed.Comment: 10 pages, 8 figure

Substantiation data for hypersonic cruise vehicle wing structure evaluation - Volume 1, sections 1-10

Trajectory, load, aerodynamic heating, materials, structural, and thermal analyses for hypersonic cruise vehicle wing

Attempting to validate the over/under triage matrix at a level I trauma center.

The Optimal Resources Document (ORD) mandates trauma activation based on injury mechanism, physiologic and anatomic criteria and recommends using the over/undertriage matrix (Matrix) to evaluate the appropriateness of trauma team activation. The purpose of this study was to assess the effectiveness of the Matrix method by comparing patients appropriately triaged with those undertriaged. We hypothesized that these two groups are different and Matrix does not discriminate the needs or outcomes of these different groups of patients.Trauma registry data, from 1/2013-12/2015, at a Level I trauma center were reviewed. Over and undertriage rates were calculated by Matrix. Patients with ISS ≥16 were classified by activation level (full, limited, consultation), and triage category by Matrix. Patients in the limited activation and consultation groups were compared to patients with full activation by demographics, injuries, initial vital signs, procedures, delays to procedure, ICU admission, length of stay, and mortality.7031 patients met activation criteria. Compliance with ACS tiered activation criteria was 99%. The Matrix overtriage rate was 45% and undertriage was 24%. Of 2282 patients with an ISS ≥16, 1026 were appropriately triaged (full activation), and 1256 were under triaged. Undertriaged patients had better GCS, blood pressure, and BD than patients with full activation. ICU admission, hospital stays, and mortality were lower in the undertriaged group. The under triaged group required fewer operative interventions with fewer delays to procedure.Despite having an ISS ≥ 16, patients with limited activations were dissimilar to patients with full activation. Level of activation and triage are not equivalent. The ACS-COT full and tiered activation criteria are a robust means to have the appropriate personnel present based on available pre-hospital information. Evaluation of the process of care, regardless of level of activation should be used to evaluate trauma center performance.Level III Therapeutic and Care managementThis is an open-access article distributed under the terms of the Creative Commons Attribution-Non Commercial-No Derivatives License 4.0 (CCBY-NC-ND), where it is permissible to download and share the work provided it is properly cited. The work cannot be changed in any way or used commercially without permission from the journal

Continuous Observation of Interference Fringes from Bose Condensates

We use continuous measurement theory to describe the evolution of two Bose condensates in an interference experiment. It is shown how the system evolves in a single run of the experiment into a state with a fixed relative phase, while the total gauge symmetry remains unbroken. Thus, an interference pattern is exhibited without violating atom number conservation.Comment: 4 pages, Postscrip

Classical Region of a Trapped Bose Gas

The classical region of a Bose gas consists of all single-particle modes that have a high average occupation and are well-described by a classical field. Highly-occupied modes only occur in massive Bose gases at ultra-cold temperatures, in contrast to the photon case where there are highly-occupied modes at all temperatures. For the Bose gas the number of these modes is dependent on the temperature, the total number of particles and their interaction strength. In this paper we characterize the classical region of a harmonically trapped Bose gas over a wide parameter regime. We use a Hartree-Fock approach to account for the effects of interactions, which we observe to significantly change the classical region as compared to the idealized case. We compare our results to full classical field calculations and show that the Hartree-Fock approach provides a qualitatively accurate description of classical region for the interacting gas.Comment: 6 pages, 5 figures; updated to include new results with interaction

LANDSAT-4 horizon scanner performance evaluation

Representative data spans covering a little more than a year since the LANDSAT-4 launch were analyzed to evaluate the flight performance of the satellite's horizon scanner. High frequency noise was filtered out by 128-point averaging. The effects of Earth oblateness and spacecraft altitude variations are modeled, and residual systematic errors are analyzed. A model for the predicted radiance effects is compared with the flight data and deficiencies in the radiance effects modeling are noted. Correction coefficients are provided for a finite Fourier series representation of the systematic errors in the data. Analysis of the seasonal dependence of the coefficients indicates the effects of some early mission problems with the reference attitudes which were computed by the onboard computer using star trackers and gyro data. The effects of sun and moon interference, unexplained anomalies in the data, and sensor noise characteristics and their power spectrum are described. The variability of full orbit data averages is shown. Plots of the sensor data for all the available data spans are included

Bulk scalar field in DGP braneworld cosmology

We investigated the effects of bulk scalar field in the braneworld cosmological scenario. The Friedmann equations and acceleration condition in presence of the bulk scalar field for a zero tension brane and cosmological constant are studied. In DGP model the effective Einstein equation on the brane is obtained with bulk scalar field. The rescaled bulk scalar field on the brane in the DGP model behaves as an effective four dimensional field, thus standard type cosmology is recovered. In present study of the DGP model, the late-time accelerating phase of the universe can be explained .Comment: 10 pages, to appear in JCA

Exposure damage mechanisms for KCl windows in high power laser systems

An experimental study of the 10.6 micrometer and 0.6328 micrometer optical properties of single crystal and europium doped polycrystal is described. Significant variations in the optical properties are observed over periods of exposure up to 100 hours. Models are proposed to predict the 10.6 micrometer absorptivity for long exposure periods. Mechanical creep has been detected in both materials at high temperature