An application of theory to axial compressor noise

Mathematical model of aircraft turbocompressor nois

Community acceptance of helicopter noise: Criteria and application

A study was conducted to define those criteria necessary for civil helicopter operations to be acoustically acceptable to the communities from which they operate and over which they fly. The study involved surveying existing domestic and foreign Federal regulations and guidelines, state and local noise ordinances, results of community noise annoyance studies, and results of individual aircraft noise annoyance studies, and results of individual aircraft noise annoyance studies in order to establish the criteria. The final criteria selection are based on the Day-Night Level, L sub DN, a measure of total noise exposure. The basic rating unit is the A weighted sound pressure level (dbA) which has accuracy comparable to other units currently used for aircraft. An L sub DN of 60 is recommended as a criterion for areas where the ambient noise is below 58 dbA. An L sub DN value 2 dbA above the local ambient is recommended for areas where the ambient is above 58 dbA

Effects of blood withdrawal and reinfusion on biomarkers of erythropoiesis in humans: Implications for anti-doping strategies

To discriminate autologous blood doping procedures from normal conditions, we examined the hematological response to blood withdrawal and reinfusion. We found that biomarkers of erythropoiesis are primarily affected in the anemic period. Therefore, individual variations in [Hb] exceeding 15% between samples obtained shortly before any major competition would be indicative of autologous blood manipulation

Evaluating Feynman Integrals Using D-modules and Tropical Geometry

Feynman integrals play a central role in the modern scattering amplitudes research program. Advancing our methods for evaluating Feynman integrals will, therefore, strengthen our ability to compare theoretical predictions with data from particle accelerators such as the Large Hadron Collider. Motivated by this, the present manuscript purports to study mathematical concepts related to Feynman integrals. In particular, we present both numerical and analytical algorithms for the evaluation of Feynman integrals. The content is divided into three parts. Part I focuses on the method of DEQs for evaluating Feynman integrals. An otherwise daunting integral expression is thereby traded for the comparatively simpler task of solving a system of DEQs. We use this technique to evaluate a family of two-loop Feynman integrals of relevance for dark matter detection. Part II situates the study of DEQs for Feynman integrals within the framework of D-modules, a natural language for studying PDEs algebraically. Special emphasis is put on a particular D-module called the GKZ system, a set of higher-order PDEs that annihilate a generalized version of a Feynman integral. In the course of matching the generalized integral to a Feynman integral proper, we discover an algorithm for evaluating the latter in terms of logarithmic series. Part III develops a numerical integration algorithm. It combines Monte Carlo sampling with tropical geometry, a particular offspring of algebraic geometry that studies "piecewise-linear" polynomials. Feynman's i*epsilon-prescription is incorporated into the algorithm via contour deformation. We present an open-source program named Feyntrop that implements this algorithm, and use it to numerically evaluate Feynman integrals between 1-5 loops and 0-5 legs in physical regions of phase space.Comment: Ph.D. thesis. Defended on the 11th of December 202

Investigation of critical slowing down in a bistable S-SEED

A simulation of S-SEED switching based upon experimental data is developed that includes the effect of critical slowing down. The simulation's accuracy is demonstrated by close agreement with the results from experimental S-SEED switching. The simulation is subsequently used to understand how the phenomenon of critical slowing down applies to switching of an S-SEED and how the effect on photonic analog-to-digital (A/D) converter performance may be minimized.B. A. Clare, K. A. Corbett, K. J. Grant, P. B. Atanackovic, W. Marwood and J. Munc

Investigating 16O with the 15N(p,{\alpha})12C reaction

The 16O nucleus was investigated through the 15N(p,{\alpha})12C reaction at excitation energies from Ex = 12 231 to 15 700 keV using proton beams from a 5 MeV Van de Graaff accelerator at beam energies of Ep = 331 to 3800 keV. Alpha decay from resonant states in 16O was strongly observed for ten known excited states in this region. The candidate 4-alpha cluster state at Ex = 15.1 MeV was investigated particularly intensely in order to understand its particle decay channels.Comment: Submitted for Proceedings of Fourth International Workshop on State of the Art in Nuclear Cluster Physics (SOTANCP4), held from May 13 - 18, 2018 in Galveston, TX, US

Coherence length of single laser pulses as measured by CCD interferometry

A novel interferometric method for the direct, real-time measurement of the complete temporal coherence function of a pulsed laser is presented. A Michelson interferometer is modified by replacing one mirror with an inclined diffraction grating to observe interference fringes as a function of path-length difference on a single pulse. Computerized data acquisition and methods of extending the range of wavelengths to the infrared are discussed