A coronal wave and an asymmetric eruptive filament in SUMER, CDS, EIT, and TRACE co-observations

The objectives of the present study is to provide a better physical understanding of the complex inter-relation and evolution of several solar coronal features comprising a double-peak flare, a coronal dimming caused by a CME, a CME-driven compression, and a fast-mode wave. For the first time, the evolution of an asymmetric eruptive filament is analysed in simultaneous SUMER spectroscopic and TRACE and EIT imaging data. We use imaging observations from EIT and TRACE in the 195A channel and spectroscopic observations from the CDS in a rastering and SUMER in a sit-and-stare observing mode. The SUMER spectra cover spectral lines with formation temperatures from logT(K) ~ 4.0 to 6.1. Although the event was already analysed in two previous studies, our analysis brings a wealth of new information on the dynamics and physical properties of the observed phenomena. We found that the dynamic event is related to a complex flare with two distinct impulsive peaks, one according to the GOES classification as C1.1 and the second - C1.9. The first energy release triggers a fast-mode wave and a CME with a clear CME driven compression ahead of it. This activity is related to, or possibly caused, by an asymmetric filament eruption. The filament is observed to rise with its leading edge moving at a speed of ~300 km/s detected both in the SUMER and CDS data. The rest of the filament body moves at only ~150 km/s while untwisting. No signature is found of the fast-mode wave in the SUMER data, suggesting that the plasma disturbed by the wave had temperatures above 600 000 K. The erupting filament material is found to emit only in spectral lines at transition region temperatures. Earlier identification of a coronal response detected in the Mg X 609.79 A line is found to be caused by a blend from the O IV 609.83 A line.Comment: 10 pages, 8 figures, A&A, in pres

Validation of power system transient stability results

Simulation of the transient stability problem of a power system, which is the assessment of the short term angular and voltage stability of the system following a disturbance, is of vital importance. It is widely known in the industry that different transient stability packages can give substantially different results for the same (or at least similar) system models. The goal of this work is to develop validation methodologies for different transient stability software packages with a focus on Western Electricity Coordinating Council (WECC) system models. We discuss two specific approaches developed and implemented to validate the transient stability results. The sources of discrepancies seen in the results from different packages are investigated. This enables us to identify the differences in the implementation of dynamic models in different transient stability softwares. In this process, we present certain key analyses of the WECC system models for different contingencies

Finite element analysis and experimental validation of reinforced concrete single-mat slabs subjected to blast loads

Title from PDF of title page, viewed on June 5, 2013Thesis advisor: Ganesh ThiagarajanVitaIncludes bibliographic references (pages 152-154)Thesis (M.S.)--School of Computing and Engineering. University of Missouri---Kansas City, 2013The work done in this research is to study the response of reinforced concrete slabs subjected to blast loading as they can be used as protective structures around the main structure. An experimental investigation has been performed in a separate study involving blast-testing of 12 reinforced concrete slabs in a shock tube (Blast Load Simulator). The data from this experimental investigation was made available for performing advanced finite element analysis done in this research to study the behavior of these slabs towards blast loading. A non-linear transient dynamic finite element analysis program LS-DYNA® is used for this study. The finite element models of these 12 slab panels are developed in LS-DYNA® and blast pressures equivalent to those generated in the experiment are applied to them. These slabs include two material combinations based on their strength namely, the high-strength concrete reinforced with high-strength steel slabs and normal-strength concrete reinforced with normalstrength steel slabs. The primary objective is to study the response of material combinations to blast loading by using two different concrete material models available in LS-DYNA namely, Winfrith Concrete Model and Concrete Damage Model Release 3 and comparing it with the experimental results. Validation of these models with experimental data will provide anumerical analysis procedure which will be less expensive and safer than performing blast testing. On performing this study, finite element analysis and experimental validation of reinforced concrete single-mat slabs subjected to blast loading it is concluded that the Winfrith Concrete Model predicts a better response in terms of deflection and crack propagation for both normal and high strength concrete. Concrete Damage Model Release 3 needs additional parameters to be defined based on concrete laboratory testing data for it to predict a better response in the normal-strength and high-strength category. These additional parameters have been developed and recommended in this study.Introduction -- Literature review -- Objective and scope -- Experimental investigation -- Numerical modeling in LS-DYNA® -- Numerical analysis results and comparison with experiments -- Discussion of results -- Conclusions and future work -- Appendix A. Pressure and impulse data for 12 slabs -- Appendix B. Pressure and impulse plots for 12 RC slabs -- Appendix C. summary tables -- Appendix D. LS-DYNA inpu

A model study of the seasonal cycle of the Arabian Sea surface temperature

The Annual variation of the SST along a zonal strip from the coast of Somalia to the southwest coast of India was simulated using available data (monthly-mean heat and momentum fluxes across the air-sea interface, surface advective field, etc.) as input to a Kraus-Turner mixed-layer model. Three cases were examined. In the first, influence of surface fluxes alone was considered. The second included the effects of surface fluxes and vertical advection. Then, effect of horizontal advection was added. The model forced with the surface heat and momentum fluxes alone simulated reasonably well the SST variability throughout the year except during the May-August (southwest monsoon) cooling phase. The model was found to be inadequate to handle the coastal areas during this phase. Over the open-sea regime the performance of the model was better; and, it improved when the influence of advection was included. The important contribution of the horizontal advection during June-August was to remove most of the heat gained at the surface during the course of a year. Though downwelling in the open-sea had little influence on the SST, it had noticeable impact on the vertical heat transport. The numerical experiments suggest that the Kraus-Turner thermodynamics alone dominate the Arabian SST variability throughout the year except during the southwest monsoon, when dynamics too playa significant role

Discovering the Biological Activities of Maltose Derivatives for Controlling Bacterial Multicellular Behaviors

Since the serendipitous discovery of the first antibiotic, the wonder drug penicillin by Alexander Fleming, bacteria over time have slowly developed resistance to most antibiotics through three well coordinated processes. Firstly, bacteria can evolve their genetic makeup to become resistant against antibiotics; Secondly, bacteria can relay the modified antibiotic resistant genes to other bacteria and other species through a process called conjugation. Thirdly, bacteria quickly give up their individuality to become a part of a team to form surface attached multicellular communities known as biofilms. Bacteria residing within biofilms are protected by a layer of slime which renders the bacteria one thousand fold more resistant to the action of antibiotics. Nearly eighty percent of bacterial infections are associated with biofilms and therefore understandably, biofilms are considered as one of the seven most important health issues facing mankind in the 21st century. The focus of research work presented here is to discover small molecules that can control multiple microbial multicellular behaviors. The fundamental approach was to deploy small molecules that do not kill the bacteria (nonmicrobicidal), but are able to modulate bacterial multicellular behaviors, like biofilm formation and swarming motility, which are not essential for bacterial survival but are critical for infections. Consequently, the use of such nonmicrobicidal agents is less likely to induce evolution of bacterial genes. The use of two different kinds of nonmicrobicidal agents, maltose derivatives and brominated furanones, as modulators of different bacterial multicellular behaviors has been demonstrated. Rhamnolipids secreted by Pseudomonas aeruginosa are biosurfactants that are known to be essential for at least three multicellular behaviors of P. aeruginosa, biofilm formation, biofilm dispersion and swarming motility. Maltose derivatives, which are structurally related to rhamnolipids were synthesized and found to be nonmicrobicidal to the growth of P. aeruginosa, Escherichia coli and Staphylococcus aureus. Maltose derivatives were effective at inhibiting the initial adhesion, biofilm formation and at dispersing pre-formed biofilm of P. aeruginosa. Maltose derivatives were capable of both modulating the swarming motility of wild type P. aeruginosa (PAO1) and activating swarming of a nonswarming P. aeruginosa mutant, rhlA. Although, the maltose derivatives were able to inhibit the biofilm formation, these agents were not effective at either inhibiting the initial adhesion or dispersing the preformed biofilms of both E. coli and S. aureus. Brominated furanones are known to disrupt bacterial chemical communication process known as quorum sensing (QS). Here the mechanism of action of brominated furanones on both E. coli and P. aeruginosa was explored. The presence of a methyl substituent either on the furanone ring or on the exocylic vinyl bond was identified as an important structural element for maintaining nonmicrobicidal action. The protein SdiA of E. coli was found to be critical for antibiofilm activities of brominated furanones against E. coli. The lasI protein on P. aeruginosa is a known homologue of the E. coli SdiA protein. It was found that the brominated furanones were antagonistic to the las QS system but were agonistic to the rhl QS system of P. aeruginosa. The nonmicrobicidal agents presented here, maltose derivative and brominated furanones offer new approaches for controlling biofilm and bacteria-related problems

Influence Phase of a dS Observer I : Scalar Exchange

Inspired by real-time computations in AdS black holes, we propose a method to obtain the influence phase of a cosmological observer by calculating the on-shell action on a doubled spacetime geometry. The influence phase is the effective action for an open system: for a dS static patch observer coupled to a scalar field it incorporates the radiation reaction due to the bulk fields and their dS Hawking radiation. For a general extended source in dS, we describe how to account for finite size effects. In the long-time limit, we get a Markovian open quantum system susceptible to cosmological fluctuations, whereas the short-time limit reproduces the worldline theory of flat-space radiation reaction. We also present a fully covariantised form for the cubic corrections to the radiation reaction in even spacetime dimensions, including Hubble contributions, and find an intriguing recursive structure across dimensions.Comment: 22 pages + 46 pages of appendices. v2: minor improvement

Medical Data Architecture Prototype Development - Summary of Recent Work and Proposed Ideas for Upcoming Work

The Medical Data Architecture (MDA) project supports the Exploration Medical Capability (ExMC) risk to minimize or reduce the risk of adverse health outcomes and decrements in performance due to in-flight medical capabilities on human exploration missions. To mitigate this risk, the ExMC MDA project addresses the technical limitations identified in ExMC Gap Med 07: We do not have the capability to comprehensively process medically-relevant information to support medical operations during exploration missions, and in ExMC Gap Med 10: We do not have the capability to provide computed medical decision support during exploration missions. These gaps recognize the need for a comprehensive medical data management system and the accompanying computational support to provide autonomous medical care during long duration exploration missions. As the MDA maturesincluding the capability to comprehensively process and discover medically-relevant information to support medical operations during exploration missionsproject focus will shift to maturing and extending the MDA platform to enable clinical decision support and real-time guidance. To date, the MDA foundational architecture has recommended exploration medical system Level of Care IV requirements through a series of test bed prototype developments and analog demonstrations. The next stage in the development will focus on more autonomous clinical decision making necessary to address challenges in executing a self-contained medical system that enables health care both with and without assistance from ground support. A thorough understanding of current state of medical decision support systems, advanced machine learning algorithms and vast and varied data sources is required. The development of a clinical decision support for exploration missions (Level of Care V) roadmap is needed: one that assesses of current state of the art of clinical decision support systems (CDSS), interoperability issues, identification of challenges in health and performance monitoring, obtaining and processing information from biosensors, knowledge and data management, data integration and fusion, and advanced algorithm development. This roadmap must also include rapid prototype development in the areas of data processing, advanced analysis and prediction of medical events, and treatment based on medically relevant information processing and evidence-based best practices. In this presentation, an overview of the relevant issues and the beginning framework of a Level of Care V CDSS development roadmap will be provided

Tides in the Mandovi and Zuari estuaries, Goa, west coast of India

Mandovi and Zuari are two estuaries located in Goa, west coast of India. Variation of water level in the estuaries was monitored for a month at 13 locations using tide-poles during March-April 2003. Analysis of this data has provided for the first time, characteristics of how tidal constituents vary in the narrow and shallow estuaries, typical of those found along the west coast of India. At a distance of 45 km from the mouth the tidal range increased in both estuaries by approximately 20%. The tidal range at the upstream end of the two channels at the stations dropped sharply because of the increase in elevation of the channels