Two phase detonation studies

An experimental study of the passage of a shock wave over a burning fuel drop is described. This includes high speed framing photographs of the interaction taken at 500,000 frames per second. A theoretical prediction of the ignition of a fuel drop by a shock wave is presented and the results compared with earlier experimental work. Experimental attempts to generate a detonation in a liquid fuel drop (kerosene)-liquid oxidizer drop (hydrogen peroxide)-inert gas-environment are described. An appendix is included which gives the analytical prediction of power requirements for the drop generator to produce certain size drops at a certain mass rate. A bibliography is also included which lists all of the publications resulting from this research grant

Barriers and facilitators to healthy eating for nurses in the workplace: an integrative review

© 2016 John Wiley & Sons Ltd Aim: The aim was to conduct an integrative systematic review to identify barriers and facilitators to healthy eating for working nurses. Background: There is growing recognition of the influence of the workplace environment on the eating habits of the workforce, which in turn may contribute to increased overweight and obesity. Overweight and obesity exact enormous costs in terms of reduced well-being, worker productivity and increased risk of non-communicable diseases. The workplace is an ideal place to intervene and support healthy behaviours. This review aimed to identify barriers and facilitators to nurses’ healthy eating in the workplace. Design: Integrative mixed method review. Data sources: Five electronic databases were searched: CINAHL, MEDLINE, PROQUEST Health and Medicine, ScienceDirect and PsycINFO. Reference lists were searched. Included papers were published in English between 2000–2016. Of 26 included papers, 21 were qualitative and five quantitative. Review methods: An integrative literature review was undertaken. Quality appraisal of included studies used standardized checklists. A social-ecological framework was used to examine workplace facilitators and constraints to healthy eating, derived from the literature. Emergent themes were identified by thematic analysis. Results: Review participants were Registered, Enrolled and/or Nurse Assistants primarily working in hospitals in middle or high income countries. The majority of studies reported barriers to healthy eating related to adverse work schedules, individual barriers, aspects of the physical workplace environment and social eating practices at work. Few facilitators were reported. Overall, studies found the workplace exerts a considerable negative influence on nurses’ dietary intake. Conclusion: Reorientation of the workplace to promote healthy eating among nurses is required

Introduction to Categories and Categorical Logic

The aim of these notes is to provide a succinct, accessible introduction to some of the basic ideas of category theory and categorical logic. The notes are based on a lecture course given at Oxford over the past few years. They contain numerous exercises, and hopefully will prove useful for self-study by those seeking a first introduction to the subject, with fairly minimal prerequisites. The coverage is by no means comprehensive, but should provide a good basis for further study; a guide to further reading is included. The main prerequisite is a basic familiarity with the elements of discrete mathematics: sets, relations and functions. An Appendix contains a summary of what we will need, and it may be useful to review this first. In addition, some prior exposure to abstract algebra - vector spaces and linear maps, or groups and group homomorphisms - would be helpful.Comment: 96 page

Multi-transmission-line-beam interactive system

We construct here a Lagrangian field formulation for a system consisting of an electron beam interacting with a slow-wave structure modeled by a possibly non-uniform multiple transmission line (MTL). In the case of a single line we recover the linear model of a traveling wave tube (TWT) due to J.R. Pierce. Since a properly chosen MTL can approximate a real waveguide structure with any desired accuracy, the proposed model can be used in particular for design optimization. Furthermore, the Lagrangian formulation provides for: (i) a clear identification of the mathematical source of amplification, (ii) exact expressions for the conserved energy and its flux distributions obtained from the Noether theorem. In the case of uniform MTLs we carry out an exhaustive analysis of eigenmodes and find sharp conditions on the parameters of the system to provide for amplifying regimes

Probing Minimal Supergravity at the CERN LHC for Large tan⁡β\tan\beta

For large values of the minimal supergravity model parameter $\tan\beta$, the tau lepton and the bottom quark Yukawa couplings become large, leading to reduced masses of $\tau$-sleptons and $b$-squarks relative to their first and second generation counterparts, and to enhanced decays of charginos and neutralinos to $\tau$-leptons and $b$-quarks. We evaluate the reach of the CERN LHC $pp$ collider for supersymmetry in the mSUGRA model parameter space. We find that values of $m_{\tg}\sim 1500-2000$ GeV can be probed with just 10 fb$^{-1}$ of integrated luminosity for $\tan\beta$ values as high as 45, so that mSUGRA cannot escape the scrutiny of LHC experiments by virtue of having a large value of $\tan\beta$. We also perform a case study of an mSUGRA model at $\tan\beta =45$ where \tz_2\to \tau\ttau_1 and \tw_1\to \ttau_1\nu_\tau with $\sim 100$ branching fraction. In this case, at least within our simplistic study, we show that a di-tau mass edge, which determines the value of m_{\tz_2}-m_{\tz_1}, can still be reconstructed. This information can be used as a starting point for reconstructing SUSY cascade decays on an event-by-event basis, and can provide a strong constraint in determining the underlying model parameters. Finally, we show that for large $\tan\beta$ there can be an observable excess of $\tau$ leptons, and argue that $\tau$ signals might serve to provide new information about the underlying model framework.Comment: 22 page REVTEX file including 8 figure

A High Throughput Workflow Environment for Cosmological Simulations

The next generation of wide-area sky surveys offer the power to place extremely precise constraints on cosmological parameters and to test the source of cosmic acceleration. These observational programs will employ multiple techniques based on a variety of statistical signatures of galaxies and large-scale structure. These techniques have sources of systematic error that need to be understood at the percent-level in order to fully leverage the power of next-generation catalogs. Simulations of large-scale structure provide the means to characterize these uncertainties. We are using XSEDE resources to produce multiple synthetic sky surveys of galaxies and large-scale structure in support of science analysis for the Dark Energy Survey. In order to scale up our production to the level of fifty 10^10-particle simulations, we are working to embed production control within the Apache Airavata workflow environment. We explain our methods and report how the workflow has reduced production time by 40% compared to manual management.Comment: 8 pages, 5 figures. V2 corrects an error in figure

The Reach of the Fermilab Tevatron and CERN LHC for Gaugino Mediated SUSY Breaking Models

In supersymmetric models with gaugino mediated SUSY breaking (inoMSB), it is assumed that SUSY breaking on a hidden brane is communicated to the visible brane via gauge superfields which propagate in the bulk. This leads to GUT models where the common gaugino mass $m_{1/2}$ is the only soft SUSY breaking term to receive contributions at tree level. To obtain a viable phenomenology, it is assumed that the gaugino mass is induced at some scale $M_c$ beyond the GUT scale, and that additional renormalization group running takes place between $M_c$ and $M_{GUT}$ as in a SUSY GUT. We assume an SU(5) SUSY GUT above the GUT scale, and compute the SUSY particle spectrum expected in models with inoMSB. We use the Monte Carlo program ISAJET to simulate signals within the inoMSB model, and compute the SUSY reach including cuts and triggers approriate to Fermilab Tevatron and CERN LHC experiments. We find no reach for SUSY by the Tevatron collider in the trilepton channel. %either with or without %identified tau leptons. At the CERN LHC, values of $m_{1/2}=1000$ (1160) GeV can be probed with 10 (100) fb$^{-1}$ of integrated luminosity, corresponding to a reach in terms of $m_{\tg}$ of 2150 (2500) GeV. The inoMSB model and mSUGRA can likely only be differentiated at a linear $e^+e^-$ collider with sufficient energy to produce sleptons and charginos.Comment: 17 page revtex file with 9 PS figure

Quantum Films Adsorbed on Graphite: Third and Fourth Helium Layers

Using a path-integral Monte Carlo method for simulating superfluid quantum films, we investigate helium layers adsorbed on a substrate consisting of graphite plus two solid helium layers. Our results for the promotion densities and the dependence of the superfluid density on coverage are in agreement with experiment. We can also explain certain features of the measured heat capacity as a function of temperature and coverage.Comment: 13 pages in the Phys. Rev. two-column format, 16 Figure