376 research outputs found

    Master of Science

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    thesisThis thesis presents the design and optimization of a biologically inspired wet shape memory alloy (SMA) actuated pump that can provide thermal energy via fluidic convection to actuate external wet SMA subsystems. Furthermore, the pump draws from its own fluidic output to assist in the actuation of its own internal SMA actuators. A thorough analysis of the previous wet SMA robotic heart is conducted by searching for opportunities for improvement. Methods of improving the pump's output-to-input ratio included modifying the pumping chambers, actuation cycle timing, implementing electrical actuation, and continuously adding heat to the system. Dynamic modeling was performed to provide a baseline indicator of what was to be expected during actual implementation and testing. The effects of changing various parameters were explored to determine optimal configurations. Key parameters affecting performance include mechanical advantage, actuator length, flow durations, and water temperature. Implemented design changes and testing confirmed the modeling results. Continuous heating of the hot water within the pressurized accumulator greatly enhanced the pump's performance. Using only fluidic induced actuation, the output-to-input ratio peaked at 1.4. The pump reached an output-to-input ratio of 2.1 with the aid of electrical actuation. This is the first successful implementation of a self-sustaining thermofluidically powered SMA pump. Furthermore, unlike other SMA micropumps that typically output 1 mL/min or less, this pump is capable of a macroscale net output of 66 mL/min. While the pump's output exceeds the required input, the power efficiency and power density of the pump do not compare to that of the human heart due to the amount of power required to keep the hot water continuously heated. Viable options for improving efficiency and power density include minimizing pump mass, optimizing pumping chamber design, and reducing the amount of heat necessary to keep the hot water at an elevated temperature

    Supply chain security: the need for continuous assessment

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    Ease of Internet accessibility has offered business the opportunity to incorporate this electronic infrastructure technology into establishing electronic-based supply chains. With the improved efficiency that this brings to the management and functionality of the supply chain, there are also security considerations that should be taken into account for protecting the integrity of the electronic supply chain, not only within each business node, but also across the entire supply chain. Such security vulnerabilities can be negated with the implementation of security measures and policies, however these need to be consistent throughout the supply chain and regularly assessed against security benchmarks in order to ensure they meet dequate security standards.</div

    Percutaneous Externally Assembled Laparoscopic (PEAL) Donor Nephrectomy: A Cohort Pain Comparison

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    Donor nephrectomies can be technically demanding. Donors also may not be fully psychologically prepared for their post-operative pain or cosmetic outcome. A novel Percutaneous Externally Assembled Laparoscopic (PEAL) paradigm was developed to decrease incisional pain and laparoscopic scars. The aim of this study is to compare the post-operative outcomes between donor nephrectomies performed with and without the PEAL instruments

    Reproductive Failure in UK Harbour Porpoises Phocoena phocoena : Legacy of Pollutant Exposure?

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    This research was supported by a Marie Curie International Outgoing Fellowship within the Seventh European Community Framework Programme (Project Cetacean-stressors, PIOF-GA-2010-276145 to PDJ and SM). Additional funding was provided through the Agreement on the Conservation of Small Cetaceans of the Baltic, North East Atlantic, Irish and North Seas (ASCOBANS) (Grants SSFA/2008 and SSFA / ASCOBANS / 2010 / 5 to SM). Analysis of Scottish reproductive and teeth samples was funded by the EC-funded BIOCET project (BIOaccumulation of persistent organic pollutants in small CETaceans in European waters: transport pathways and impact on reproduction, grant EVK3-2000-00027 to GJP), and Marine Scotland (GJP). Samples examined in this research were collected under the collaborative Cetacean Strandings Investigation Programme (http://ukstrandings.org/), which is funded by the Department for Environment, Food and Rural Affairs (Defra) and the UK’s Devolved Administrations in Scotland and Wales (http://sciencesearch.defra.gov.uk/Defaul​t.aspx?Menu=Menu&Module=More&Location=No​ne&Completed=0&ProjectID=15331) (grants to PDJ, RD). UK Defra also funded the chemical analysis under a service-level agreement with the Centre for Environment, Fisheries and Aquaculture Science (grants to RJL, JB). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

    Cyberinfrastructure, Science Gateways, Campus Bridging, and Cloud Computing

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    Computers accelerate our ability to achieve scientific breakthroughs. As technology evolves and new research needs come to light, the role for cyberinfrastructure as “knowledge” infrastructure continues to expand. This article defines and discusses cyberinfrastructure and the related topics of science gateways and campus bridging; identifies future challenges in cyberinfrastructure; and discusses challenges and opportunities related to the evolution of cyberinfrastructure, “big data” (datacentric, data-enabled, and data-intensive research and data analytics), and cloud computing.This material is based upon work supported by the National Science Foundation under grants 0504075, 0451237, 0723054, 1062432, 0116050, 0521433, 0503697, and 1053575, and several IBM Shared University Research grants and support provided by Lilly Endowment, Inc. for the Indiana University Pervasive Technology Institute. Any opinions, findings and conclusions or recommendations expressed herein are those of the authors and do not necessarily reflect the views of the supporting agencies

    Mental Health Symptom Severity in Cannabis-Using and Non-Using Veterans with probable PTSD

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    BACKGROUND: Posttraumatic Stress Disorder (PTSD) is a disabling illness suffered by many veterans returning from war. Some veterans believe that cannabis may be therapeutic for PTSD. The purpose of this study was to better understand the association between cannabis use and PTSD symptoms. METHODS: The study was a matched case-control cross-sectional evaluation of the psychiatric and sociocultural associations of cannabis use in veterans with probable PTSD. Patient self-report measures were examined comparing cannabis users (cases) to non-users (controls) who were case-matched on age and gender. RESULTS: Results indicated that there were no significant differences between cases and controls in mean PTSD Checklist-Civilian version (PCL-C) scores (59.2 and 59.1, respectively). There was also no association between PTSD scores and frequency of cannabis use. It was also observed that cases were more likely to be non-Caucasian, financially challenged, and unmarried. LIMITATIONS: The sample is a convenience sample of veterans being referred for a clinical assessment and, therefore, sampling biases may limit the generalizability of the results to other populations including veterans not seeking health care in the Veterans Affairs (VA) system. CONCLUSIONS: The results do not support the theory that cannabis use would be associated with less severe PTSD symptoms. Results do suggest important sociocultural differences in cannabis users compared to controls

    Acoustic metamaterial absorbers based on multilayered sonic crystals

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    Through the use of a layered arrangement, it is shown that lossy sonic crystals can be arranged to create a structure with extreme acoustic properties, namely, an acoustic metamaterial. This artificial structure shows different effective fluids and absorptive properties in different orientations. Theoretical, numerical, and experimental results examining thermoviscous losses in sonic crystals are presented, enabling the fabrication and characterization of an acoustic metamaterial absorber with complex-valued anisotropic inertia. To accurately describe and fabricate such an acoustic metamaterial in a realizable experimental configuration, confining structures are needed which modify the effective properties, due to the thermal and viscous boundary layer effects within the sonic crystal lattice. Theoretical formulations are presented which describe the effects of these confined sonic crystals, both individually and as part of an acoustic metamaterial structure. Experimental demonstrations are also reported using an acoustic impedance tube. The formulations developed can be written with no unknown or empirical coefficients, due to the structured lattice of the sonic crystals and organized layering scheme; and it is shown that higher filling fraction arrangements can be used to provide a large enhancement in the loss factor. (C) 2015 AIP Publishing LLC.This work was supported by the U.S. Office of Naval Research (Award No. N000141210216) and by the Spanish Ministerio de Economia y Competitividad (MINECO) under Contract No. TEC2010-19751.Guild, M.; García Chocano, VM.; Kan, W.; Sánchez-Dehesa Moreno-Cid, J. (2015). Acoustic metamaterial absorbers based on multilayered sonic crystals. Journal of Applied Physics. 117(11):114902-1-114902-14. https://doi.org/10.1063/1.4915346S114902-1114902-1411711Dowling, J. P. (1992). Sonic band structure in fluids with periodic density variations. 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New Journal of Physics, 10(11), 115032. doi:10.1088/1367-2630/10/11/115032Popa, B.-I., & Cummer, S. A. (2009). Design and characterization of broadband acoustic composite metamaterials. Physical Review B, 80(17). doi:10.1103/physrevb.80.174303Torrent, D., & Sánchez-Dehesa, J. (2010). Anisotropic Mass Density by Radially Periodic Fluid Structures. Physical Review Letters, 105(17). doi:10.1103/physrevlett.105.174301Gumen, L. N., Arriaga, J., & Krokhin, A. A. (2011). Metafluid with anisotropic dynamic mass. Low Temperature Physics, 37(11), 975-978. doi:10.1063/1.3672821Zigoneanu, L., Popa, B.-I., Starr, A. F., & Cummer, S. A. (2011). Design and measurements of a broadband two-dimensional acoustic metamaterial with anisotropic effective mass density. Journal of Applied Physics, 109(5), 054906. doi:10.1063/1.3552990Reyes-Ayona, E., Torrent, D., & Sánchez-Dehesa, J. (2012). Homogenization theory for periodic distributions of elastic cylinders embedded in a viscous fluid. The Journal of the Acoustical Society of America, 132(4), 2896-2908. doi:10.1121/1.4744933Naify, C. J., Chang, C.-M., McKnight, G., & Nutt, S. (2010). Transmission loss and dynamic response of membrane-type locally resonant acoustic metamaterials. Journal of Applied Physics, 108(11), 114905. doi:10.1063/1.3514082Yang, Z., Dai, H. M., Chan, N. H., Ma, G. C., & Sheng, P. (2010). Acoustic metamaterial panels for sound attenuation in the 50–1000 Hz regime. Applied Physics Letters, 96(4), 041906. doi:10.1063/1.3299007Naify, C. J., Chang, C.-M., McKnight, G., Scheulen, F., & Nutt, S. (2011). Membrane-type metamaterials: Transmission loss of multi-celled arrays. Journal of Applied Physics, 109(10), 104902. doi:10.1063/1.3583656Hussein, M. I., & Frazier, M. J. (2013). Metadamping: An emergent phenomenon in dissipative metamaterials. Journal of Sound and Vibration, 332(20), 4767-4774. doi:10.1016/j.jsv.2013.04.041Zhang, Y., Wen, J., Zhao, H., Yu, D., Cai, L., & Wen, X. (2013). 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    The Feasibility of Percutaneous Externally Assembled Laparoscopic Nephrectomy: a New Surgical System

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    Laparoendoscopic single-site (LESS) nephrectomy provides excellent cosmetic outcomes, but is technically challenging due to loss of triangulation and increased instrument collision. A novel Percutaneous Externally Assembled Laparoscopic (PEAL) surgical system was developed to simplify minimally invasive surgery while providing a nearly scarless outcome. In this study, the feasibility of the PEAL system for nephrectomy was determined

    Multiple Forensic Interviews During Investigations of Child Sexual Abuse: A Cost-Effectiveness Analysis

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    In cases of suspected child sexual abuse (CSA) some professionals routinely recommend multiple interviews by the same interviewer because any additional details provided might improve decision-making and increase perpetrator convictions. We analyzed alternative policies about child interviewing to estimate the probability that a policy of all children receiving multiple interviews will increase criminal convictions and better protect children. Using decision analysis, we prepared a decision tree reflecting the structure through which a case of possible CSA passes through the health care, welfare, and legal systems with an estimated probability of conviction of the offender. We reviewed the CSA disclosure, criminal justice, and child welfare literature to obtain estimates for the median and range of rates for the steps of disclosure, substantiation, criminal charges, and conviction. Using the R statistical package, our decision analysis model was populated using literature-based estimates. Once the model was populated, we simulated the experiences of 1,000 cases at 250 sets of plausible parameter values representing different hypothetical communities. Multiple interviews increase the likelihood that an offender will be convicted by 6.1% in the average community. Simulations indicate that a policy in which all children seen for a CSA medical evaluation receive multiple interviews would cost an additional $100,000 for each additional conviction. We estimate that approximately 17 additional children would need to be interviewed on more than one occasion to yield one additional conviction. A policy of multiple interviews has implications for the children, for the costs of care, for protecting other children, and for the risk of false prosecution
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