An investigation on vibration-based damage detection in circular plates

This study aims at the development of vibration-based health monitoring (VHM) methodology for thin circular plates. The possibility of using the first several natural frequencies of a circular plate for damage detection purposes is investigated first. The study then suggests a damage detection method, which considers a vibrating plate as a dynamic system and uses its time domain response represented in a new phase (state) space to extract damage sensitive characteristics. The paper introduces the idea of using large amplitude vibrations and nonlinear time series analysis for damage detection purposes. The suggested damage detection approach explores the possibility to use certain characteristics of the distribution of phase space points on the attractor of the system. It studies the histograms of this distribution and attempts to extract damage sensitive features. Three damage features are suggested and they are shown to detect damage at a rather low level using a finite element model of the plate. The method suggested is rather generic and permits development and application to more complex structures and real data

Use of record-linkage to handle non-response and improve alcohol consumption estimates in health survey data: a study protocol

<p>Introduction: Reliable estimates of health-related behaviours, such as levels of alcohol consumption in the population, are required to formulate and evaluate policies. National surveys provide such data; validity depends on generalisability, but this is threatened by declining response levels. Attempts to address bias arising from non-response are typically limited to survey weights based on sociodemographic characteristics, which do not capture differential health and related behaviours within categories. This project aims to explore and address non-response bias in health surveys with a focus on alcohol consumption.</p> <p>Methods and analysis: The Scottish Health Surveys (SHeS) aim to provide estimates representative of the Scottish population living in private households. Survey data of consenting participants (92% of the achieved sample) have been record-linked to routine hospital admission (Scottish Morbidity Records (SMR)) and mortality (from National Records of Scotland (NRS)) data for surveys conducted in 1995, 1998, 2003, 2008, 2009 and 2010 (total adult sample size around 40 000), with maximum follow-up of 16 years. Also available are census information and SMR/NRS data for the general population. Comparisons of alcohol-related mortality and hospital admission rates in the linked SHeS-SMR/NRS with those in the general population will be made. Survey data will be augmented by quantification of differences to refine alcohol consumption estimates through the application of multiple imputation or inverse probability weighting. The resulting corrected estimates of population alcohol consumption will enable superior policy evaluation. An advanced weighting procedure will be developed for wider use.</p> <p>Ethics and dissemination: Ethics approval for SHeS has been given by the National Health Service (NHS) Multi-Centre Research Ethics Committee and use of linked data has been approved by the Privacy Advisory Committee to the Board of NHS National Services Scotland and Registrar General. Funding has been granted by the MRC. The outputs will include four or five public health and statistical methodological international journal and conference papers.</p&gt

Research Is a Partner in Forward Focused Time

The complexities of modern society and the dynamic forces of progress necessitate that professionals in every discipline be forward-focused, which is believed to come from gaining higher education. This is becoming standard within the fire and emergency services professions and is commonly a factor regarding upward mobility. With that in mind, the U.S. Fire Administration/National Fire Academy (NFA) developed the Fire and Emergency Services Higher Education (FESHE) recognition certificate

Implications of surface noise for the motional coherence of trapped ions

Electric noise from metallic surfaces is a major obstacle towards quantum applications with trapped ions due to motional heating of the ions. Here, we discuss how the same noise source can also lead to pure dephasing of motional quantum states. The mechanism is particularly relevant at small ion-surface distances, thus imposing a new constraint on trap miniaturization. By means of a free induction decay experiment, we measure the dephasing time of the motion of a single ion trapped 50~$\mu$m above a Cu-Al surface. From the dephasing times we extract the integrated noise below the secular frequency of the ion. We find that none of the most commonly discussed surface noise models for ion traps describes both, the observed heating as well as the measured dephasing, satisfactorily. Thus, our measurements provide a benchmark for future models for the electric noise emitted by metallic surfaces.Comment: (5 pages, 4 figures

Interactive 3-D Software in Aircraft Rescue and Fire Fighting Training

As the nexus between aviation, fire science, and emergency management becomes increasingly more complex, technology can be used to augment training and avoid risk while maintaining authenticity with situational reality. In Aircraft Rescue & Fire Fighting (ARFF), the manner in which the learning content is effectively imparted to the student-professional can make all the difference in a successful emergency response. The interactive 3-D software developed exclusively for Dallas/Fort Worth Fire Training Research Center (DFW FTRC) is part of a curriculum designed to educated and train ARFF professionals in life-saving strategies and tactics. Through a 2013 Memorandum of Understanding, the world’s leading aviation and aerospace university, Embry-Riddle Aeronautical University (ERAU), and DFW FTRC have created a unique partnership for the conduct of research to explore emerging issues in the discipline. Researchers from ERAU designed this collaborative study to examine how effectively the DFW FTRC virtual technology software in the classroom translated knowledge and accelerated haptic skill transfer to the hands-on portion of ARFF training at the facility. The qualitative approach integrated classroom observations with key informant interviews to create a single-case study exploratory research strategy. Emergent themes led to a richer understanding of experiential learning, particularly key differences among individual student characteristics and instructional culture that influence student proficiency and attitudes. Most noteworthy were: a larger interest among international over domestic students, age/generational difficulties with new technology, and an apprehension among ARFF professionals to transition from traditional tabletop exercises to virtual reality. Variability also existed within the instructional culture, including inconsistencies of software integration in the classroom, instructor proficiency with the software, and adult and group teaching theories. The study also found that knowledge and accelerated haptic skill transfer were positively associated with the virtual reality software, and that interactive participation and memory reinforcement were supported by the findings. Time required for curriculum development advancing further integration of the software into the training program was a significant administrative and operational challenge. Software recommendations included options that allow scenario-specific applications and variable incident conditions, thus enriching each classroom learning experience. Marketing of this software remains the final task for DFW FTRC, as cost-effective distribution could revolutionize training across public safety. Future research should also evaluate pedagogy to categorize learning constructivism using simulator-based and software-supported education and training. How this may be applied to public safety professions where risk is an inherent part of training is a crucial need in the industry

"Restricted Movement" and Coordinates of Freedom: Southern Chain Gangs in Twentieth-Century American Literature and Film

Thesis advisor: Christopher P. WilsonFor more than a century, the chain gang has been glamorized, criticized, abhorred, and often explained away as an economic necessity or natural byproduct of historical circumstances. After Emancipation, this centuries-old approach to punishing criminals offered an immediate palliative for southern plantation owners in need of field hands, northern coal and steel interests and railroad tycoons in search of blasters and miners, and eventually government officials who identified the South's antiquated infrastructure as its greatest barrier to integration into a regional and national economy. Heavily influenced by Hollywood, the blues, oral histories and folkways, archived photographs, and literary representations, many people now view the chain gang as a relic of a bygone era of southern prejudice and brutality. After all, history does not cast the men and women who served on chain gangs as heroic workers and, if they are acknowledged at all, they are only occasionally figured as victims of the political, social, and economic forces that led to their convictions and servitude. And yet, paradoxically, labor historians and others have argued convincingly that the chain gang, even with all its warts and abuses, actually made southern economic progress possible. Entering this still-vibrant, contested territory, "Restricted Movement" and Coordinates of Freedom focuses on depictions of chain gangs in selected literary works and films from 1901 to 2000, including Charles W. Chesnutt's The Marrow of Tradition (1901) and All the King's Men (1946) by Robert Penn Warren and the films I Am a Fugitive from a Chain Gang (1932), Sullivan's Travels (1941), The Defiant Ones (1958), and O Brother, Where Art Thou? (2000). This dissertation attempts to make sense of a multitude of historical and social conditions that bear specifically on chain gangs and convict labor, including black criminality, white supremacy, the Good Roads Movement, race-based electoral politics, and industrialization. In addition to exploring these vexed arguments about servitude and progress, this dissertation also explores how the chain gang, real and imagined, serves as its own special form of segregation. Beginning with the work of Edward L. Ayers, Alex Lichtenstein, Matthew Mancini, and others in the 1980s and 1990s, a handful of southern and labor historians broadened the study of postbellum race, crime, and punishment to consider whether convict-leasing programs and chain gangs in the late nineteenth and early twentieth centuries really did result in a form of "neo-slavery." In other words, these historians asked, did these practices actually "re-enslave" African Americans in the American South between 1865 and 1940? And if so, what were the social, political and cultural implications of this re-enslavement? How did these practices shape the experience and consciousness of both blacks and southern whites? Moreover, in a culture that speaks so often of slavery's terrible legacies, how might a deeper understanding of convict leasing and chain gangs offer its own particular lessons about race, history, and justice in the United States since the Civil War? My hope is that the methods and approaches laid out in this dissertation will invite other scholars to grapple with the ways in which chain gang history and cultural history inform one another.Thesis (PhD) — Boston College, 2012.Submitted to: Boston College. Graduate School of Arts and Sciences.Discipline: English

Fingering Instability in Combustion

A thin solid (e.g., paper), burning against an oxidizing wind, develops a fingering instability with two decoupled length scales. The spacing between fingers is determined by the P\'eclet number (ratio between advection and diffusion). The finger width is determined by the degree two dimensionality. Dense fingers develop by recurrent tip splitting. The effect is observed when vertical mass transport (due to gravity) is suppressed. The experimental results quantitatively verify a model based on diffusion limited transport

Learning from Asiana 214--Minimizing Strike/Rollover for Aircraft Rescue and Firefighting

Following the crash of Asiana flight 214 on July 6, 2013, the National Transportation Safety Board (NTSB) provided a recommendation to the Aircraft Rescue & Fire Fighting Working Group (ARFFWG) to develop best practices to avoid strike/rollover of seriously injured or deceased persons in mass casualty situations. This paper summarizes the research process and the technical committee’s conclusions. The qualitative inquiry used participatory research and evaluation from medico-legal professionals and the expert committee comprised of 21 aircraft rescue and firefighting experts. Key informants were complemented by documentary analysis, including FAA Advisory Circulars, regulations, standards, medical and aircraft rescue industry publications. The research provides specific committee recommendations for establishing control zones in the mass casualty environment, using START for triage, surveillance, transportation, training and certification of both ARFF personnel and incident command, and airport emergency planning strategies. A best practice for ARFF personnel, which is a tactical procedure for task prioritization at aircraft crash incidents, is also proposed. The authors suggest future pilot testing for evaluation of these best practices following NTSB’s consent with the committee’s recommendations

Libyan Boy with Autosomal Recessive Trait (P22-phox Defect) of Chronic Granulomatous Disease

Chronic granulomatous disease (CGD) is a primary immune deficiency disorder of the phagocytes. In this disorder, phagocytic cells (polymorphonuclear leukocytes and monocytes) cannot produce active oxygen metabolites and, therefore, cannot destroy the ingested intracellular bacteria. Clinically, patients with CGD usually have recurrent bacterial and fungal infections causing abscess and granuloma formation in the skin, lymph nodes and visceral organs

Additive opportunistic capture explains group hunting benefits in African wild dogs

African wild dogs (Lycaon pictus) are described as highly collaborative endurance pursuit hunters based on observations derived primarily from the grass plains of East Africa. However, the remaining population of this endangered species mainly occupies mixed woodland savannah where hunting strategies appear to differ from those previously described. We used high-resolution GPS and inertial technology to record fine-scale movement of all members of a single pack of six adult African wild dogs in northern Botswana. The dogs used multiple short-distance hunting attempts with a low individual kill rate (15.5%), but high group feeding rate due to the sharing of prey. Use of high-level cooperative chase strategies (coordination and collaboration) was not recorded. In the mixed woodland habitats typical of their current range, simultaneous, opportunistic, short-distance chasing by dogs pursuing multiple prey (rather than long collaborative pursuits of single prey by multiple individuals) could be the key to their relative success in these habitats