147 research outputs found
Surviving the Monsoon: Natural Hazards in Bangladesh
The students will compare the features of Bangladesh with the features of Iowa
Test Using Sedimentary Records to Quantify Extreme Paleo-flood: A Case Study of an Oxbow Lake in South Carolina
Extreme flooding has become an increasing issue along the coasts for people’s health and infrastructure stability. As the effect of climate change continues to persist, the need to prepare for such events becomes imperative. To improve the understanding of climatic forecasting with regards to extreme flooding, there is merit in searching flooding history beyond the instrumental records. There has been some work done in the past to correlate extreme flooding and its sedimentary traces preserved in floodplain depressions, such as oxbow lakes, based on the assumption that the coarser grain sediments in the sediment layers correspond with higher peak discharges brought on by flooding. In this study, we test this correlation using a core sample (1.24 m long) taken from an oxbow lake off the main channel of the Waccamaw River in South Carolina. Grain size of the core sediment was measured for every centimeter to investigate how that might correspond with extreme flooding of the Waccamaw River during the ~60-year life span of the lake. To calculate a reliable range of sediment coarseness, two separate parameters were used, the grain size at 90% cumulative frequency distribution, D90, and the most coarse component through end-member modeling (EMM). The parameters were detrended and normalized to determine the z-scores, or standard scores, for each layer. The z-scores of both parameters depicting coarse sediments corresponded strongly with the peak annual discharge of extreme flooding events (\u3e 9000 cfs) with a correlation coefficient (r2) of 0.45 for D90 and 0.77 for the EMM analysis. The confidence between these correlations can open up future research opportunities for more articulate paleo-flood records. An analysis of the peak annual discharge of the Waccamaw River over the last ~70 years indicates that the majority of the extreme discharges are caused by tropical cyclones, suggesting that the history of extreme flooding of this river may reveal how historical tropical cyclones have affected this region
Modeling Telemedicine Systems to Effectively Allocate Administrative and Medical Resources
David Ben-AriehTelemedicine stands as one of the most promising innovations in healthcare. By delivering healthcare through electronic means, doctors can greatly expand the number and geographic diversity of patients they serve. While most telemedicine today focuses on more traditional health care applications, telemental health aims to apply telemedicine principles to mental health services. Telemental systems offer convenient and efficient ways for healthcare providers to provide psychological and psychiatric service to patients in far-flung geographic areas. Unfortunately, these systems can suffer from serious congestion if not well put-together. Maximizing the valuable time of doctors while ensuring short waits for patients should be a primary goal of telemedicine system design. Telemental health systems come in several varieties such as synchronous, asynchronous, and group telemental health. Each variety offers different system properties and flow behavior. This paper presents models for synchronous, asynchronous, and group telemental health systems using a discrete-event simulation and examines their properties using that tool. It compares their relative performance in this way. The analysis determines effective system capacity and demonstrates the effect of expanding the number of doctors and patients in the system. Moreover, the results can serve as a tool for healthcare providers seeking to establish telemental health systems. The models revealed that, given a single specialist, nurse, set of audiovisual equipment, and administrative team, group telemedicine offered the highest capacity of roughly 300 patients at a time. Asynchronous individual systems followed with a capacity of 30, and synchronous individual systems trailed with a capacity of 25. As capacity decreases, however, the configuration’s ability to provide patients with one-on-one care rises. The proper selection depends on the needs of the patient and the demands on the provider. The analysis also extends to some modifications of the original models that remove assumptions made in describing group telemedicine, probe the impact of variance reduction, and examine the maximum number of specialists a single administrative team can handle
Methodology for computational fluid dynamics code verification /validation
The issues of verification, calibration, and validation of computational fluid dynamics (CFD) codes has been receiving increasing levels of attention in the research literature and in engineering technology. Both CFD researchers and users of CFD codes are asking more critical and detailed questions concerning the accuracy, range of applicability, reliability and robustness of CFD codes and their predictions. This is a welcomed trend because it demonstrates that CFD is maturing from a research tool to the world of impacting engineering hardware and system design. In this environment, the broad issue of code quality assurance becomes paramount. However, the philosophy and methodology of building confidence in CFD code predictions has proven to be more difficult than many expected. A wide variety of physical modeling errors and discretization errors are discussed. Here, discretization errors refer to all errors caused by conversion of the original partial differential equations to algebraic equations, and their solution. Boundary conditions for both the partial differential equations and the discretized equations will be discussed. Contrasts are drawn between the assumptions and actual use of numerical method consistency and stability. Comments are also made concerning the existence and uniqueness of solutions for both the partial differential equations and the discrete equations. Various techniques are suggested for the detection and estimation of errors caused by physical modeling and discretization of the partial differential equations
Print versus digital texts: understanding the experimental research and challenging the dichotomies
This article presents the results of a systematic critical review of interdisciplinary literature concerned with digital text (or e-text) uses in education and proposes recommendations for how e-texts can be implemented for impactful learning. A variety of e-texts can be found in the repertoire of educational resources accessible to students, and in the constantly changing terrain of educational technologies, they are rapidly evolving, presenting new opportunities and affordances for student learning. We highlight some of the ways in which academic studies have examined e-texts as part of teaching and learning practices, placing a particular emphasis on aspects of learning such as recall, comprehension, retention of information and feedback. We also review diverse practices associated with uses of e-text tools such as note-taking, annotation, bookmarking, hypertexts and highlighting. We argue that evidence-based studies into e-texts are overwhelmingly structured around reinforcing the existing dichotomy pitting print-based (‘traditional’) texts against e-texts. In this article, we query this approach and instead propose to focus on factors such as students’ level of awareness of their options in accessing learning materials and whether they are instructed and trained in how to take full advantage of the capabilities of e-texts, both of which have been found to affect learning performance
Arch Height in Individuals with Multiple Sclerosis: A Pilot Study
Multiple Sclerosis (MS) is the most common neurological disorder affecting younger adults. MS causes demyelination of nerves in the central nervous system, which impairs the ability of the nerve to conduct its impulse to other nerves and muscles. Over time, weaknesses and sensory deficits in the limbs may lead to structural changes in the musculoskeletal system, such as tightness in certain muscles and joints (calf and ankle) and excessive motion in others (foot and knee). Structural changes in the foot, including arch height and mid-foot flexibility, have yet to be measured or studied in persons with MS.https://ecommons.udayton.edu/dpt_symposium/1009/thumbnail.jp
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Large-scale structure evolution in axisymmetric, compressible free-shear layers
This paper is a description of work-in-progress. It describes Sandia`s program to study the basic fluid mechanics of large-scale mixing in unbounded, compressible, turbulent flows, specifically, the turbulent mixing of an axisymmetric compressible helium jet in a parallel, coflowing compressible air freestream. Both jet and freestream velocities are variable over a broad range, providing a wide range mixing layer Reynolds number. Although the convective Mach number, M{sub c}, range is currently limited by the present nozzle design to values of 0.6 and below, straightforward nozzle design changes would permit a wide range of convective Mach number, to well in excess of 1.0. The use of helium allows simulation of a hot jet due to the large density difference, and also aids in obtaining optical flow visualization via schlieren due to the large density gradient in the mixing layer. The work comprises a blend of analysis, experiment, and direct numerical simulation (DNS). There the authors discuss only the analytical and experimental efforts to observe and describe the evolution of the large-scale structures. The DNS work, used to compute local two-point velocity correlation data, will be discussed elsewhere
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Use of shear-stress-sensitive, temperature-insensitive liquid crystals for hypersonic boundary-layer transition detection
The use of shear-stress-sensitive, temperature-insensitive (SSS/TI) liquid crystals (LCs) has been evaluated as a boundary-layer transition detection technique for hypersonic flows. Experiments were conducted at Mach 8 in the Sandia National Laboratories Hypersonic Wind Tunnel using a flat plate model at near zero-degree angle of attack over the freestream unit Reynolds number range 1.2-5.8x10{sup 6}/ft. Standard 35mm color photography and Super VHS color video were used to record LC color changes due to varying surface shear stress during the transition process for a range of commercial SSS liquid crystals. Visual transition data were compared to an established method using calorimetric surface heat-transfer measurements to evaluate the LC technique. It is concluded that the use of SSS/TI LCs can be an inexpensive, safe, and easy to use boundary-layer transition detection method for hypersonic flows. However, a valid interpretation of the visual records requires careful attention to illumination intensity levels and uniformity, lighting and viewing angles, some prior understanding of the general character of the flow, and the selection of the appropriate liquid crystal for the particular flow conditions
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