157 research outputs found

    Aerodynamic Simulation of Runback Ice Accretion

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    This report presents the results of recent investigations into the aerodynamics of simulated runback ice accretion on airfoils. Aerodynamic tests were performed on a full-scale model using a high-fidelity, ice-casting simulation at near-flight Reynolds (Re) number. The ice-casting simulation was attached to the leading edge of a 72-in. (1828.8-mm ) chord NACA 23012 airfoil model. Aerodynamic performance tests were conducted at the ONERA F1 pressurized wind tunnel over a Reynolds number range of 4.7?10(exp 6) to 16.0?10(exp 6) and a Mach (M) number ran ge of 0.10 to 0.28. For Re = 16.0?10(exp 6) and M = 0.20, the simulated runback ice accretion on the airfoil decreased the maximum lift coe fficient from 1.82 to 1.51 and decreased the stalling angle of attack from 18.1deg to 15.0deg. The pitching-moment slope was also increased and the drag coefficient was increased by more than a factor of two. In general, the performance effects were insensitive to Reynolds numb er and Mach number changes over the range tested. Follow-on, subscale aerodynamic tests were conducted on a quarter-scale NACA 23012 model (18-in. (457.2-mm) chord) at Re = 1.8?10(exp 6) and M = 0.18, using low-fidelity, geometrically scaled simulations of the full-scale castin g. It was found that simple, two-dimensional simulations of the upper- and lower-surface runback ridges provided the best representation of the full-scale, high Reynolds number iced-airfoil aerodynamics, whereas higher-fidelity simulations resulted in larger performance degrada tions. The experimental results were used to define a new subclassification of spanwise ridge ice that distinguishes between short and tall ridges. This subclassification is based upon the flow field and resulting aerodynamic characteristics, regardless of the physical size of the ridge and the ice-accretion mechanism

    An optimized BSCCO/Ag resonator coil for utility use

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    AC coils made with BSCCO-2223/Ag tapes and operating in liquid nitrogen have a potential for power related applications, e.g., inductors, transformers and current limiters. High-Tc tapes are available from several producers, while access to the coil building know-help is still rather limited, The relevant knowledge and technology suitable for making HTS coils for 50-60 Hz operation is being developed as a part of the current project. To verify the technology, several test solenoids and a first full-scale sub-coil have been manufactured. Electromagnetic, thermal and mechanical analysis of the coils is performed. The electromagnetic analysis focuses on the reduction of the radial magnetic field component in the windings. Voltage-current characteristics and the AC loss data obtained from relevant short sample measurements are applied. A good agreement between calculated and measured V-I curves and losses of the coils is found. A remarkable increase of the critical current and the reduction of the AC loss at the coil edges are predicted and confirmed experimentally. With the losses defined, thermal analysis and optimization of the coil structure are performed numerically followed by measurements for verification. The paper reports on the series of coils developed and explains the features of the projec

    Mitigative Measures for At-risk Public Surface Water Supply Systems in Illinois

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    published or submitted for publicationis peer reviewedOpe

    A kinematic analysis of a haptic handheld stylus in a virtual environment: a study in healthy subjects

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    <p>Abstract</p> <p>Background</p> <p>Virtual Reality provides new options for conducting motor assessment and training within computer-generated 3 dimensional environments. To date very little has been reported about normal performance in virtual environments. The objective of this study was to evaluate the test-retest reliability of a clinical procedure measuring trajectories with a haptic handheld stylus in a virtual environment and to establish normative data in healthy subjects using this haptic device.</p> <p>Methods</p> <p>Fifty-eight normal subjects; aged from 20 to 69, performed 3 dimensional hand movements in a virtual environment using a haptic device on three occasions within one week. Test-retest stability and standardized normative data were obtained for all subjects.</p> <p>Results</p> <p>No difference was found between test and retest. The limits of agreement revealed that changes in an individual's performance could not be detected. There was a training effect between the first test occasion and the third test occasion. Normative data are presented.</p> <p>Conclusion</p> <p>A new test was developed for recording the kinematics of the handheld haptic stylus in a virtual environment. The normative data will be used for purposes of comparison in future assessments, such as before and after training of persons with neurological deficits.</p

    Translation of evidence-based Assistive Technologies into stroke rehabilitation: Users' perceptions of the barriers and opportunities

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    Background: Assistive Technologies (ATs), defined as "electrical or mechanical devices designed to help people recover movement", demonstrate clinical benefits in upper limb stroke rehabilitation; however translation into clinical practice is poor. Uptake is dependent on a complex relationship between all stakeholders. Our aim was to understand patients', carers' (P&Cs) and healthcare professionals' (HCPs) experience and views of upper limb rehabilitation and ATs, to identify barriers and opportunities critical to the effective translation of ATs into clinical practice. This work was conducted in the UK, which has a state funded healthcare system, but the findings have relevance to all healthcare systems. Methods. Two structurally comparable questionnaires, one for P&Cs and one for HCPs, were designed, piloted and completed anonymously. Wide distribution of the questionnaires provided data from HCPs with experience of stroke rehabilitation and P&Cs who had experience of stroke. Questionnaires were designed based on themes identified from four focus groups held with HCPs and P&Cs and piloted with a sample of HCPs (N = 24) and P&Cs (N = 8). Eight of whom (four HCPs and four P&Cs) had been involved in the development. Results: 292 HCPs and 123 P&Cs questionnaires were analysed. 120 (41%) of HCP and 79 (64%) of P&C respondents had never used ATs. Most views were common to both groups, citing lack of information and access to ATs as the main reasons for not using them. Both HCPs (N = 53 [34%]) and P&C (N = 21 [47%]) cited Functional Electrical Stimulation (FES) as the most frequently used AT. Research evidence was rated by HCPs as the most important factor in the design of an ideal technology, yet ATs they used or prescribed were not supported by research evidence. P&Cs rated ease of set-up and comfort more highly. Conclusion: Key barriers to translation of ATs into clinical practice are lack of knowledge, education, awareness and access. Perceptions about arm rehabilitation post-stroke are similar between HCPs and P&Cs. Based on our findings, improvements in AT design, pragmatic clinical evaluation, better knowledge and awareness and improvement in provision of services will contribute to better and cost-effective upper limb stroke rehabilitation. © 2014 Hughes et al.; licensee BioMed Central Ltd

    Validation of a low-cost virtual reality system for training street-crossing. A comparative study in healthy, neglected and non-neglected stroke individuals

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    Unilateral spatial neglect is a common consequence of stroke that directly affects the performance of activities of daily living. This impairment is traditionally assessed with paper-and-pencil tests that can lack correspondence to real life and are easily compensated. Virtual reality can immerse patients in more ecological scenarios, thus providing therapists with new tools to assess and train the effects of this impairment in simulated real tasks. This paper presents the clinical validation and convergent validity of a low-cost virtual reality system for training street-crossing in stroke patients with and without neglect. The performance of neglect patients was significantly worse than the performance of non-neglect and healthy participants. In addition, several correlations between the scores in the system and in the traditional scales were detected.This study was funded in part by Ministerio de Educacion y Ciencia Spain, Projects Consolider-C (SEJ2006-14301/PSIC), "CIBER of Physiopathology of Obesity and Nutrition, an initiative of ISCIII" and the Excellence Research Program PROMETEO (Generalitat Valenciana. Conselleria de Educacion, 2008-157).Navarro, MD.; Llorens Rodríguez, R.; Noé, E.; Ferri, J.; Alcañiz Raya, ML. (2013). Validation of a low-cost virtual reality system for training street-crossing. A comparative study in healthy, neglected and non-neglected stroke individuals. Neuropsychological Rehabilitation. 23(4):597-618. https://doi.org/10.1080/09602011.2013.806269S597618234Allegri, R. F. (2000). Atención y negligencia: bases neurológicas, evaluación y trastornos. Revista de Neurología, 30(05), 491. doi:10.33588/rn.3005.99645Appelros, P., Karlsson, G. M., Seiger, &#x000C5;ke, & Nydevik, I. (2002). Neglect and Anosognosia After First-Ever Stroke: Incidence and Relationship to Disability. Journal of Rehabilitation Medicine, 34(5), 215-220. doi:10.1080/165019702760279206Baheux, K., Yoshizawa, M., & Yoshida, Y. (2007). Simulating hemispatial neglect with virtual reality. Journal of NeuroEngineering and Rehabilitation, 4(1). doi:10.1186/1743-0003-4-27Boian, R. F., Burdea, G. C., Deutsch, J. E. and Winter, S. H. Street crossing using a virtual environment mobility simulator.Paper presented at 3rd Annual International Workshop on Virtual Reality. Lausanne, Switzerland.Broeren, J., Samuelsson, H., Stibrant-Sunnerhagen, K., Blomstrand, C., & Rydmark, M. (2007). Neglect assessment as an application of virtual reality. Acta Neurologica Scandinavica, 116(3), 157-163. doi:10.1111/j.1600-0404.2007.00821.xBuxbaum, L. J., Ferraro, M. K., Veramonti, T., Farne, A., Whyte, J., Ladavas, E., … Coslett, H. B. (2004). Hemispatial neglect: Subtypes, neuroanatomy, and disability. Neurology, 62(5), 749-756. doi:10.1212/01.wnl.0000113730.73031.f4Buxbaum, L. J., Palermo, M. A., Mastrogiovanni, D., Read, M. S., Rosenberg-Pitonyak, E., Rizzo, A. A., & Coslett, H. B. (2008). Assessment of spatial attention and neglect with a virtual wheelchair navigation task. Journal of Clinical and Experimental Neuropsychology, 30(6), 650-660. doi:10.1080/13803390701625821Castiello, U., Lusher, D., Burton, C., Glover, S., & Disler, P. (2004). Improving left hemispatial neglect using virtual reality. Neurology, 62(11), 1958-1962. doi:10.1212/01.wnl.0000128183.63917.02Conners, C. K., Epstein, J. N., Angold, A., & Klaric, J. (2003). Journal of Abnormal Child Psychology, 31(5), 555-562. doi:10.1023/a:1025457300409Folstein, M. F., Folstein, S. E., & McHugh, P. R. (1975). «Mini-mental state». Journal of Psychiatric Research, 12(3), 189-198. doi:10.1016/0022-3956(75)90026-6Fordell, H., Bodin, K., Bucht, G., & Malm, J. (2011). A virtual reality test battery for assessment and screening of spatial neglect. Acta Neurologica Scandinavica, 123(3), 167-174. doi:10.1111/j.1600-0404.2010.01390.xGupta, V., Knott, B. A., Kodgi, S., & Lathan, C. E. (2000). Using the «VREye» System for the Assessment of Unilateral Visual Neglect: Two Case Reports. Presence: Teleoperators and Virtual Environments, 9(3), 268-286. doi:10.1162/105474600566790Hartman-Maeir, A., & Katz, N. (1995). Validity of the Behavioral Inattention Test (BIT): Relationships With Functional Tasks. American Journal of Occupational Therapy, 49(6), 507-516. doi:10.5014/ajot.49.6.507Jannink, M. J. A., Aznar, M., de Kort, A. C., van de Vis, W., Veltink, P., & van der Kooij, H. (2009). Assessment of visuospatial neglect in stroke patients using virtual reality: a pilot study. International Journal of Rehabilitation Research, 32(4), 280-286. doi:10.1097/mrr.0b013e3283013b1cJehkonen, M., Laihosalo, M., & Kettunen, J. (2006). Anosognosia after stroke: assessment, occurrence, subtypes and impact on functional outcome reviewed. Acta Neurologica Scandinavica, 114(5), 293-306. doi:10.1111/j.1600-0404.2006.00723.xKatz, N., Ring, H., Naveh, Y., Kizony, R., Feintuch, U., & Weiss, P. L. (2005). Interactive virtual environment training for safe street crossing of right hemisphere stroke patients with Unilateral Spatial Neglect. Disability and Rehabilitation, 27(20), 1235-1244. doi:10.1080/09638280500076079Kim, D. Y., Ku, J., Chang, W. H., Park, T. H., Lim, J. Y., Han, K., … Kim, S. I. (2010). Assessment of post-stroke extrapersonal neglect using a three-dimensional immersive virtual street crossing program. Acta Neurologica Scandinavica, 121(3), 171-177. doi:10.1111/j.1600-0404.2009.01194.xKim, J., Kim, K., Kim, D. Y., Chang, W. H., Park, C.-I., Ohn, S. H., … Kim, S. I. (2007). Virtual Environment Training System for Rehabilitation of Stroke Patients with Unilateral Neglect: Crossing the Virtual Street. CyberPsychology & Behavior, 10(1), 7-15. doi:10.1089/cpb.2006.9998Kim, K., Kim, J., Ku, J., Kim, D. Y., Chang, W. H., Shin, D. I., … Kim, S. I. (2004). A Virtual Reality Assessment and Training System for Unilateral Neglect. CyberPsychology & Behavior, 7(6), 742-749. doi:10.1089/cpb.2004.7.742Kim, Y. M., Chun, M. H., Yun, G. J., Song, Y. J., & Young, H. E. (2011). The Effect of Virtual Reality Training on Unilateral Spatial Neglect in Stroke Patients. Annals of Rehabilitation Medicine, 35(3), 309. doi:10.5535/arm.2011.35.3.309Krakauer, J. W. (2006). Motor learning: its relevance to stroke recovery and neurorehabilitation. Current Opinion in Neurology, 19(1), 84-90. doi:10.1097/01.wco.0000200544.29915.ccMcComas, J., MacKay, M., & Pivik, J. (2002). Effectiveness of Virtual Reality for Teaching Pedestrian Safety. CyberPsychology & Behavior, 5(3), 185-190. doi:10.1089/109493102760147150Myers, R. L., & Bierig, T. A. (2000). Virtual Reality and Left Hemineglect: A Technology for Assessment and Therapy. CyberPsychology & Behavior, 3(3), 465-468. doi:10.1089/10949310050078922Peskine, A., Rosso, C., Box, N., Galland, A., Caron, E., Rautureau, G., … Pradat-Diehl, P. (2010). Virtual reality assessment for visuospatial neglect: importance of a dynamic task. Journal of Neurology, Neurosurgery & Psychiatry, 82(12), 1407-1409. doi:10.1136/jnnp.2010.217513Romero, M., Sánchez, A., Marín, C., Navarro, M. D., Ferri, J., & Noé, E. (2012). Utilidad clínica de la versión en castellano del Mississippi Aphasia Screening Test (MASTsp): validación en pacientes con ictus. Neurología, 27(4), 216-224. doi:10.1016/j.nrl.2011.06.006Rose, F. D., Brooks, B. M., & Rizzo, A. A. (2005). Virtual Reality in Brain Damage Rehabilitation: Review. CyberPsychology & Behavior, 8(3), 241-262. doi:10.1089/cpb.2005.8.241Schwebel, D. C., & McClure, L. A. (2010). Using virtual reality to train children in safe street-crossing skills. 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    Behavioral Inhibition as a Risk Factor for the Development of Childhood Anxiety Disorders: A Longitudinal Study

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    This longitudinal study examined the additive and interactive effects of behavioral inhibition and a wide range of other vulnerability factors in the development of anxiety problems in youths. A sample of 261 children, aged 5 to 8 years, 124 behaviorally inhibited and 137 control children, were followed during a 3-year period. Assessments took place on three occasions to measure children’s level of behavioral inhibition, anxiety disorder symptoms, other psychopathological symptoms, and a number of other vulnerability factors such as insecure attachment, negative parenting styles, adverse life events, and parental anxiety. Results obtained with Structural Equation Modeling indicated that behavioral inhibition primarily acted as a specific risk factor for the development of social anxiety symptoms. Furthermore, the longitudinal model showed additive as well as interactive effects for various vulnerability factors on the development of anxiety symptoms. That is, main effects of anxious rearing and parental trait anxiety were found, whereas behavioral inhibition and attachment had an interactive effect on anxiety symptomatology. Moreover, behavioral inhibition itself was also influenced by some of the vulnerability factors. These results provide support for dynamic, multifactorial models for the etiology of child anxiety problems
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