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Sample records for adaptive behavior composite

  1. Static aeroelastic behavior of an adaptive laminated piezoelectric composite wing

    NASA Technical Reports Server (NTRS)

    Weisshaar, T. A.; Ehlers, S. M.

    1990-01-01

    The effect of using an adaptive material to modify the static aeroelastic behavior of a uniform wing is examined. The wing structure is idealized as a laminated sandwich structure with piezoelectric layers in the upper and lower skins. A feedback system that senses the wing root loads applies a constant electric field to the piezoelectric actuator. Modification of pure torsional deformaton behavior and pure bending deformation are investigated, as is the case of an anisotropic composite swept wing. The use of piezoelectric actuators to create an adaptive structure is found to alter static aeroelastic behavior in that the proper choice of the feedback gain can increase or decrease the aeroelastic divergence speed. This concept also may be used to actively change the lift effectiveness of a wing. The ability to modify static aeroelastic behavior is limited by physical limitations of the piezoelectric material and the manner in which it is integrated into the parent structure.

  2. Adaptive multifunctional composites

    NASA Astrophysics Data System (ADS)

    Wang, Ya; Inman, Daniel J.

    2013-05-01

    The adaptive multifunctional composite structure studied here is to address two issues remaining in lightweight structural composites required by many engineering applications. The first is to add additional functionality to multifunctional composites and the second is to provide adaptive damping in structures that cover a wide range of frequencies and temperatures. Because of its potential for practical payoffs, passive structural damping can find wide application through the use of high-damping viscoelastic polymers or elastomers. However, all passive damping using these damping materials suffer from failing at certain temperatures and in certain frequency ranges. The extreme environments often seen by engineering systems provide high temperature, which is exactly where damping levels in structures reduce causing unacceptable vibrations. In addition, as loading frequencies reduce damping levels also fall off, and many loads experienced by large structures are low frequency. The proposed research addresses increasing the range of effectiveness of damping by addressing the temperature and frequency dependence of material damping by using a multifunctional composite system containing an active element. Previous research has yielded a finite element model of linear viscoelastic material and structural behavior that captures characteristic frequency-dependent behavior, continuing research has addressed the accommodation of temperature dependence, and the examination of the new concept of `electronic damping' or `e-damping'. The resulting modeling approach is validated through experimental validation.

  3. Vibrational behavior of adaptive aircraft wing structures modelled as composite thin-walled beams

    NASA Technical Reports Server (NTRS)

    Song, O.; Librescu, L.; Rogers, C. A.

    1992-01-01

    The vibrational behavior of cantilevered aircraft wings modeled as thin-walled beams and incorporating piezoelectric effects is studied. Based on the converse piezoelectric effect, the system of piezoelectric actuators conveniently located on the wing yield the control of its associated vertical and lateral bending eigenfrequencies. The possibility revealed by this study enabling one to increase adaptively the eigenfrequencies of thin-walled cantilevered beams could play a significant role in the control of the dynamic response and flutter of wing and rotor blade structures.

  4. Adaptive Composite Map Projections.

    PubMed

    Jenny, B

    2012-12-01

    All major web mapping services use the web Mercator projection. This is a poor choice for maps of the entire globe or areas of the size of continents or larger countries because the Mercator projection shows medium and higher latitudes with extreme areal distortion and provides an erroneous impression of distances and relative areas. The web Mercator projection is also not able to show the entire globe, as polar latitudes cannot be mapped. When selecting an alternative projection for information visualization, rivaling factors have to be taken into account, such as map scale, the geographic area shown, the map's height-to-width ratio, and the type of cartographic visualization. It is impossible for a single map projection to meet the requirements for all these factors. The proposed composite map projection combines several projections that are recommended in cartographic literature and seamlessly morphs map space as the user changes map scale or the geographic region displayed. The composite projection adapts the map's geometry to scale, to the map's height-to-width ratio, and to the central latitude of the displayed area by replacing projections and adjusting their parameters. The composite projection shows the entire globe including poles; it portrays continents or larger countries with less distortion (optionally without areal distortion); and it can morph to the web Mercator projection for maps showing small regions.

  5. Probabilistic assessment of uncertain adaptive hybrid composites

    NASA Technical Reports Server (NTRS)

    Shiao, Michael C.; Singhal, Surendra N.; Chamis, Christos C.

    1994-01-01

    Adaptive composite structures using actuation materials, such as piezoelectric fibers, were assessed probabilistically utilizing intraply hybrid composite mechanics in conjunction with probabilistic composite structural analysis. Uncertainties associated with the actuation material as well as the uncertainties in the regular (traditional) composite material properties were quantified and considered in the assessment. Static and buckling analyses were performed for rectangular panels with various boundary conditions and different control arrangements. The probability density functions of the structural behavior, such as maximum displacement and critical buckling load, were computationally simulated. The results of the assessment indicate that improved design and reliability can be achieved with actuation material.

  6. Adaptive capture of expert behavior

    SciTech Connect

    Jones, R.D.; Barrett, C.L.; Hand, U.; Gordon, R.C.

    1994-08-01

    The authors smoothed and captured a set of expert rules with adaptive networks. The motivation for doing this is discussed. (1) Smoothing leads to stabler control actions. (2) For some sets of rules, the evaluation of the rules can be sped up. This is important in large-scale simulations where many intelligent elements are present. (3) Variability of the intelligent elements can be achieved by adjusting the weights in an adaptive network. (4) After capture has occurred, the weights can be adjusted based on performance criteria. The authors thus have the capability of learning a new set of rules that lead to better performance. The set of rules the authors chose to capture were based on a set of threat determining rules for tank commanders. The approach in this paper: (1) They smoothed the rules. The rule set was converted into a simple set of arithmetic statements. Continuous, non-binary inputs, are now permitted. (2) An operational measure of capturability was developed. (3) They chose four candidate networks for the rule set capture: (a) multi-linear network, (b) adaptive partial least squares, (c) connectionist normalized local spline (CNLS) network, and (d) CNLS net with a PLS preprocessor. These networks were able to capture the rule set to within a few percent. For the simple tank rule set, the multi-linear network performed the best. When the rules were modified to include more nonlinear behavior, CNLS net performed better than the other three nets which made linear assumptions. (4) The networks were tested for robustness to input noise. Noise levels of plus or minus 10% had no real effect on the network performance. Noise levels in the plus or minus 30% range degraded performance by a factor of two. Some performance enhancement occurred when the networks were trained with noisy data. (5) The scaling of the evaluation time was calculated. (6) Human variation can be mimicked in all the networks by perturbing the weights.

  7. Visualizing Search Behavior with Adaptive Discriminations

    PubMed Central

    Cook, Robert G.; Qadri, Muhammad A. J.

    2014-01-01

    We examined different aspects of the visual search behavior of a pigeon using an open-ended, adaptive testing procedure controlled by a genetic algorithm. The animal had to accurately search for and peck a gray target element randomly located from among a variable number of surrounding darker and lighter distractor elements. Display composition was controlled by a genetic algorithm involving the multivariate configuration of different parameters or genes (number of distractors, element size, shape, spacing, target brightness, and distractor brightness). Sessions were composed of random displays, testing randomized combinations of these genes, and selected displays, representing the varied descendants of displays correctly identified by the pigeon. Testing a larger number of random displays than done previously, it was found that the bird’s solution to the search task was highly stable and did not change with extensive experience in the task. The location and shape of this attractor was visualized using multivariate behavioral surfaces in which element size and the number of distractors were the most important factors controlling search accuracy and search time. The resulting visualizations of the bird’s search behavior are discussed with reference to the potential of using adaptive, open-ended experimental techniques for investigating animal cognition and their implications for Bond and Kamil’s innovative development of virtual ecologies using an analogous methodology. PMID:24370702

  8. Adaptive Behavior Profiles of Students with Disabilities

    ERIC Educational Resources Information Center

    Ditterline, Jeffrey; Banner, Diane; Oakland, Thomas; Becton, Daniel

    2008-01-01

    Assessment of adaptive behavior traditionally has been associated with the identification of individuals with mental retardation. Information on adaptive behavior increasingly is being used for comprehensive assessment, treatment planning, intervention, and program evaluation for individuals with various disorders. Data from the normative samples…

  9. Using Behavioral Questionnaires to Identify Adaptive Deficits in Elementary School Children.

    ERIC Educational Resources Information Center

    Pearson, Deborah A.; Lachar, David

    1994-01-01

    Obtained responses to Child Behavior Checklist (CBCL) and revised Personality Inventory for Children (PIC-R) for 88 elementary-age boys. Used CBCL and PIC-R scales to predict three domain scales and Adaptive Behavior Composite from Vineland Adaptive Behavior Scales. Results suggest that behavioral questionnaires can be used to efficiently identify…

  10. Balthazar Scales of Adaptive Behavior: II. Scales of Social Adaption.

    ERIC Educational Resources Information Center

    Balthazar, Earl E.

    The Balthazar Scales of Adaptive Behavior II (BSAB-II) provides a system for program development and evaluation and for social behavior assessment of profoundly and severely mentally retarded individuals as well as of the younger less retarded and emotionally disturbed individuals. The specimen set consists of six parts: a Manual, a Tally Sheet…

  11. Complex adaptive behavior and dexterous action

    PubMed Central

    Harrison, Steven J.; Stergiou, Nicholas

    2016-01-01

    Dexterous action, as conceptualized by Bernstein in his influential ecological analysis of human behavior, is revealed in the ability to flexibly generate behaviors that are adaptively tailored to the demands of the context in which they are embedded. Conceived as complex adaptive behavior, dexterity depends upon the qualities of robustness and degeneracy, and is supported by the functional complexity of the agent-environment system. Using Bernstein’s and Gibson’s ecological analyses of behavior situated in natural environments as conceptual touchstones, we consider the hypothesis that complex adaptive behavior capitalizes upon general principles of self-organization. Here, we outline a perspective in which the complex interactivity of nervous-system, body, and environment is revealed as an essential resource for adaptive behavior. From this perspective, we consider the implications for interpreting the functionality and dysfunctionality of human behavior. This paper demonstrates that, optimal variability, the topic of this special issue, is a logical consequence of interpreting the functionality of human behavior as complex adaptive behavior. PMID:26375932

  12. Complex Adaptive Behavior and Dexterous Action.

    PubMed

    Harrison, Steven J; Stergiou, Nicholas

    2015-10-01

    Dexterous action, as conceptualized by Bernstein in his influential ecological analysis of human behavior, is revealed in the ability to flexibly generate behaviors that are adaptively tailored to the demands of the context in which they are embedded. Conceived as complex adaptive behavior, dexterity depends upon the qualities of robustness and degeneracy, and is supported by the functional complexity of the agent-environment system. Using Bernstein's and Gibson's ecological analyses of behavior situated in natural environments as conceptual touchstones, we consider the hypothesis that complex adaptive behavior capitalizes upon general principles of self-organization. Here, we outline a perspective in which the complex interactivity of nervous-system, body, and environment is revealed as an essential resource for adaptive behavior. From this perspective, we consider the implications for interpreting the functionality and dysfunctionality of human behavior. This paper demonstrates that, optimal variability, the topic of this special issue, is a logical consequence of interpreting the functionality of human behavior as complex adaptive behavior.

  13. Adaptive Controller Effects on Pilot Behavior

    NASA Technical Reports Server (NTRS)

    Trujillo, Anna C.; Gregory, Irene M.; Hempley, Lucas E.

    2014-01-01

    Adaptive control provides robustness and resilience for highly uncertain, and potentially unpredictable, flight dynamics characteristic. Some of the recent flight experiences of pilot-in-the-loop with an adaptive controller have exhibited unpredicted interactions. In retrospect, this is not surprising once it is realized that there are now two adaptive controllers interacting, the software adaptive control system and the pilot. An experiment was conducted to categorize these interactions on the pilot with an adaptive controller during control surface failures. One of the objectives of this experiment was to determine how the adaptation time of the controller affects pilots. The pitch and roll errors, and stick input increased for increasing adaptation time and during the segment when the adaptive controller was adapting. Not surprisingly, altitude, cross track and angle deviations, and vertical velocity also increase during the failure and then slowly return to pre-failure levels. Subjects may change their behavior even as an adaptive controller is adapting with additional stick inputs. Therefore, the adaptive controller should adapt as fast as possible to minimize flight track errors. This will minimize undesirable interactions between the pilot and the adaptive controller and maintain maneuvering precision.

  14. Comparison of Adaptive Behavior Measures for Children with HFASDs

    PubMed Central

    Smith, Rachael A.; Volker, Martin A.; Thomeer, Marcus L.; Lee, Gloria K.; McDonald, Christin A.

    2013-01-01

    Adaptive behavior rating scales are frequently used to gather information on the adaptive functioning of children with high-functioning autism spectrum disorders (HFASDs), yet little is known about the extent to which these measures yield comparable results. This study was conducted to (a) document the parent-rated VABS-II, BASC-2, and ABAS-II adaptive behavior profiles of 6- to 11-year-olds with HFASDs (including relative strengths and weaknesses); (b) examine the extent to which these measures yielded similar scores on comparable scales; and (c) assess potential discrepancies between cognitive ability and adaptive behavior across the measures. All three adaptive measures revealed significant deficits overall for the sample, with the VABS-II and ABAS-II indicating relative weaknesses in social skills and strengths in academic-related skills. Cross-measure comparisons indicated significant differences in the absolute magnitude of scores. In general, the VABS-II yielded significantly higher scores than the BASC-2 and ABAS-II. However, the VABS-II and ABAS-II yielded scores that did not significantly differ for adaptive social skills which is a critical area to assess for children with HFASDs. Results also indicated significant discrepancies between the children's average IQ score and their scores on the adaptive domains and composites of the three adaptive measures. PMID:23819048

  15. Adaptive Behavior for Mobile Robots

    NASA Technical Reports Server (NTRS)

    Huntsberger, Terrance

    2009-01-01

    The term "System for Mobility and Access to Rough Terrain" (SMART) denotes a theoretical framework, a control architecture, and an algorithm that implements the framework and architecture, for enabling a land-mobile robot to adapt to changing conditions. SMART is intended to enable the robot to recognize adverse terrain conditions beyond its optimal operational envelope, and, in response, to intelligently reconfigure itself (e.g., adjust suspension heights or baseline distances between suspension points) or adapt its driving techniques (e.g., engage in a crabbing motion as a switchback technique for ascending steep terrain). Conceived for original application aboard Mars rovers and similar autonomous or semi-autonomous mobile robots used in exploration of remote planets, SMART could also be applied to autonomous terrestrial vehicles to be used for search, rescue, and/or exploration on rough terrain.

  16. Development of large aperture composite adaptive optics

    NASA Astrophysics Data System (ADS)

    Kmetik, Viliam; Vitovec, Bohumil; Jiran, Lukas; Nemcova, Sarka; Zicha, Josef; Inneman, Adolf; Mikulickova, Lenka; Pavlica, Richard

    2015-01-01

    Large aperture composite adaptive optics for laser applications is investigated in cooperation of Institute of Plasma Physic, Department of Instrumentation and Control Engineering FME CTU and 5M Ltd. We are exploring opportunity of a large-size high-power-laser deformable-mirror production using a lightweight bimorph actuated structure with a composite core. In order to produce a sufficiently large operational free aperture we are developing new technologies for production of flexible core, bimorph actuator and deformable mirror reflector. Full simulation of a deformable-mirrors structure was prepared and validated by complex testing. A deformable mirror actuation and a response of a complicated structure are investigated for an accurate control of the adaptive optics. An original adaptive optics control system and a bimorph deformable mirror driver were developed. Tests of material samples, components and sub-assemblies were completed. A subscale 120 mm bimorph deformable mirror prototype was designed, fabricated and thoroughly tested. A large-size 300 mm composite-core bimorph deformable mirror was simulated and optimized, fabrication of a prototype is carried on. A measurement and testing facility is modified to accommodate large sizes optics.

  17. Adaptive human behavior in epidemiological models

    PubMed Central

    Fenichel, Eli P.; Castillo-Chavez, Carlos; Ceddia, M. G.; Chowell, Gerardo; Parra, Paula A. Gonzalez; Hickling, Graham J.; Holloway, Garth; Horan, Richard; Morin, Benjamin; Perrings, Charles; Springborn, Michael; Velazquez, Leticia; Villalobos, Cristina

    2011-01-01

    The science and management of infectious disease are entering a new stage. Increasingly public policy to manage epidemics focuses on motivating people, through social distancing policies, to alter their behavior to reduce contacts and reduce public disease risk. Person-to-person contacts drive human disease dynamics. People value such contacts and are willing to accept some disease risk to gain contact-related benefits. The cost–benefit trade-offs that shape contact behavior, and hence the course of epidemics, are often only implicitly incorporated in epidemiological models. This approach creates difficulty in parsing out the effects of adaptive behavior. We use an epidemiological–economic model of disease dynamics to explicitly model the trade-offs that drive person-to-person contact decisions. Results indicate that including adaptive human behavior significantly changes the predicted course of epidemics and that this inclusion has implications for parameter estimation and interpretation and for the development of social distancing policies. Acknowledging adaptive behavior requires a shift in thinking about epidemiological processes and parameters. PMID:21444809

  18. Adaptive human behavior in epidemiological models.

    PubMed

    Fenichel, Eli P; Castillo-Chavez, Carlos; Ceddia, M G; Chowell, Gerardo; Parra, Paula A Gonzalez; Hickling, Graham J; Holloway, Garth; Horan, Richard; Morin, Benjamin; Perrings, Charles; Springborn, Michael; Velazquez, Leticia; Villalobos, Cristina

    2011-04-12

    The science and management of infectious disease are entering a new stage. Increasingly public policy to manage epidemics focuses on motivating people, through social distancing policies, to alter their behavior to reduce contacts and reduce public disease risk. Person-to-person contacts drive human disease dynamics. People value such contacts and are willing to accept some disease risk to gain contact-related benefits. The cost-benefit trade-offs that shape contact behavior, and hence the course of epidemics, are often only implicitly incorporated in epidemiological models. This approach creates difficulty in parsing out the effects of adaptive behavior. We use an epidemiological-economic model of disease dynamics to explicitly model the trade-offs that drive person-to-person contact decisions. Results indicate that including adaptive human behavior significantly changes the predicted course of epidemics and that this inclusion has implications for parameter estimation and interpretation and for the development of social distancing policies. Acknowledging adaptive behavior requires a shift in thinking about epidemiological processes and parameters.

  19. Fracture Behavior of Ceramic Composites.

    DTIC Science & Technology

    1983-08-01

    AD-R158 810 FRACTURE BEHAVIOR OF CERAMIC COMPOSITES(U) MATERIALS i/i SCIENCES CORP SPRING HOUSE PH K W BUESKING ET AL. AUG 83 MSC/TFR/’i482/i583...the U.S. Government . D T IC ELECTEF C01 AIR FORCE OFFICE OF SCIENTIFIC RESEARCH MSC TFR 1402/1503 Bolling Air Force Base, DC August, 1983 q Ippreved...Bethlehem Pike, Spring House , PA * 215-542-8400 ." -- . ". ’- , ,,- . ..O TTr.AqRTTpf SECURITY CLASSIFICATION OF THIS PAGE (When Date Enteredl REPORT

  20. Effective Behavior of Composite Materials.

    DTIC Science & Technology

    2014-09-26

    7AD-A158 941 EFFECTIVE BEHAVIOR OF COMPOSITE MTERIRLS(A) NEW YORK i/i UNIV MY COURANT INST OF ATHEMATICAL SCIENCES 6CPAPANICOLAOU 23 APR 85 5274192... Courant ilfapphcabt e Instit.te of Math. Sciences AF0SR/NM 6c. ADDRESS Cit). State and ZIP Code, 7b. ADDRESS (City. State and ZIP Code) 251 Mercer St Bldg...Papanicolaou Courant Institute 251 Mercer Street New York, N.Y. 10012 i~istr~utlo2 During this period two thesis ipja b&have completed ’their work and have

  1. Contrarian behavior in a complex adaptive system

    NASA Astrophysics Data System (ADS)

    Liang, Y.; An, K. N.; Yang, G.; Huang, J. P.

    2013-01-01

    Contrarian behavior is a kind of self-organization in complex adaptive systems (CASs). Here we report the existence of a transition point in a model resource-allocation CAS with contrarian behavior by using human experiments, computer simulations, and theoretical analysis. The resource ratio and system predictability serve as the tuning parameter and order parameter, respectively. The transition point helps to reveal the positive or negative role of contrarian behavior. This finding is in contrast to the common belief that contrarian behavior always has a positive role in resource allocation, say, stabilizing resource allocation by shrinking the redundancy or the lack of resources. It is further shown that resource allocation can be optimized at the transition point by adding an appropriate size of contrarians. This work is also expected to be of value to some other fields ranging from management and social science to ecology and evolution.

  2. Contrarian behavior in a complex adaptive system.

    PubMed

    Liang, Y; An, K N; Yang, G; Huang, J P

    2013-01-01

    Contrarian behavior is a kind of self-organization in complex adaptive systems (CASs). Here we report the existence of a transition point in a model resource-allocation CAS with contrarian behavior by using human experiments, computer simulations, and theoretical analysis. The resource ratio and system predictability serve as the tuning parameter and order parameter, respectively. The transition point helps to reveal the positive or negative role of contrarian behavior. This finding is in contrast to the common belief that contrarian behavior always has a positive role in resource allocation, say, stabilizing resource allocation by shrinking the redundancy or the lack of resources. It is further shown that resource allocation can be optimized at the transition point by adding an appropriate size of contrarians. This work is also expected to be of value to some other fields ranging from management and social science to ecology and evolution.

  3. Grid adaption using Chimera composite overlapping meshes

    NASA Technical Reports Server (NTRS)

    Kao, Kai-Hsiung; Liou, Meng-Sing; Chow, Chuen-Yen

    1993-01-01

    The objective of this paper is to perform grid adaptation using composite over-lapping meshes in regions of large gradient to capture the salient features accurately during computation. The Chimera grid scheme, a multiple overset mesh technique, is used in combination with a Navier-Stokes solver. The numerical solution is first converged to a steady state based on an initial coarse mesh. Solution-adaptive enhancement is then performed by using a secondary fine grid system which oversets on top of the base grid in the high-gradient region, but without requiring the mesh boundaries to join in any special way. Communications through boundary interfaces between those separated grids are carried out using tri-linear interpolation. Applications to the Euler equations for shock reflections and to a shock wave/boundary layer interaction problem are tested. With the present method, the salient features are well resolved.

  4. Grid adaptation using chimera composite overlapping meshes

    NASA Technical Reports Server (NTRS)

    Kao, Kai-Hsiung; Liou, Meng-Sing; Chow, Chuen-Yen

    1994-01-01

    The objective of this paper is to perform grid adaptation using composite overlapping meshes in regions of large gradient to accurately capture the salient features during computation. The chimera grid scheme, a multiple overset mesh technique, is used in combination with a Navier-Stokes solver. The numerical solution is first converged to a steady state based on an initial coarse mesh. Solution-adaptive enhancement is then performed by using a secondary fine grid system which oversets on top of the base grid in the high-gradient region, but without requiring the mesh boundaries to join in any special way. Communications through boundary interfaces between those separated grids are carried out using trilinear interpolation. Application to the Euler equations for shock reflections and to shock wave/boundary layer interaction problem are tested. With the present method, the salient features are well-resolved.

  5. Grid adaptation using Chimera composite overlapping meshes

    NASA Technical Reports Server (NTRS)

    Kao, Kai-Hsiung; Liou, Meng-Sing; Chow, Chuen-Yen

    1993-01-01

    The objective of this paper is to perform grid adaptation using composite over-lapping meshes in regions of large gradient to capture the salient features accurately during computation. The Chimera grid scheme, a multiple overset mesh technique, is used in combination with a Navier-Stokes solver. The numerical solution is first converged to a steady state based on an initial coarse mesh. Solution-adaptive enhancement is then performed by using a secondary fine grid system which oversets on top of the base grid in the high-gradient region, but without requiring the mesh boundaries to join in any special way. Communications through boundary interfaces between those separated grids are carried out using tri-linear interpolation. Applications to the Euler equations for shock reflections and to a shock wave/boundary layer interaction problem are tested. With the present method, the salient features are well resolved.

  6. Adaptive Behavior of Children and Adolescents with Visual Impairments

    ERIC Educational Resources Information Center

    Papadopoulos, Konstantinos; Metsiou, Katerina; Agaliotis, Ioannis

    2011-01-01

    The present study explored the total adaptive behavior of children and adolescents with visual impairments, as well as their adaptive behavior in each of the domains of Communication, Daily Living Skills, and Socialization. Moreover, the predictors of the performance and developmental delay in adaptive behavior were investigated. Instrumentation…

  7. Patterns of Adaptive Behavior in Very Young Children with Autism.

    ERIC Educational Resources Information Center

    Stone, Wendy L.; Ousley, Opal Y.; Hepburn, Susan L.; Hogan, Kerry L.; Brown, Christia S.

    1999-01-01

    A study used the Vineland Adaptive Behavior Scales to investigate patterns of adaptive behavior in 30 children with autism who were under 3 years. Relative to controls, participants demonstrated weaker socialization and communication skills and greater discrepancies between adaptive behavior and mental age. The utility of the scales is discussed.…

  8. Risperidone and Adaptive Behavior in Children with Autism

    ERIC Educational Resources Information Center

    Williams, Susan K.; Scahill, Lawrence; Vitiello, Benedetto; Aman, Michael G.; Arnold, L. Eugene; McDougle, Christopher J.; McCracken, James T.; Tierney, Elaine; Ritz, Louise; Posey, David J.; Swiezy, Naomi B.; Hollway, Jill; Cronin, Pegeen; Ghuman, Jaswinder; Wheeler, Courtney; Cicchetti, Domenic; Sparrow, Sara

    2006-01-01

    Objective: To evaluate the impact of risperidone on adaptive behavior in children with autistic disorder who have serious behavior problems and to examine different methods of scoring the Vineland Adaptive Behavior Scales to measure change. Method: Forty-eight children (5 years to 16 years, 5 months) who showed behavioral improvement during acute…

  9. Nonbiased Assessment of Adaptive Behavior: Comparison of Three Instruments.

    ERIC Educational Resources Information Center

    Slate, Neldea M.

    1983-01-01

    A study involving 157 fourth graders revealed that the Adaptive Behavior Inventory for Children discriminated between adaptive and maladaptive behaviors among retarded and nonretarded Ss, while the Vineland produced significantly different scores for Anglos and Blacks. The Behavior Rating Profile did not discriminate between behavior of retarded…

  10. Adaptive locomotor behavior in larval zebrafish.

    PubMed

    Portugues, Ruben; Engert, Florian

    2011-01-01

    In this study we report that larval zebrafish display adaptive locomotor output that can be driven by unexpected visual feedback. We develop a new assay that addresses visuomotor integration in restrained larval zebrafish. The assay involves a closed-loop environment in which the visual feedback a larva receives depends on its own motor output in a way that resembles freely swimming conditions. The experimenter can control the gain of this closed feedback loop, so that following a given motor output the larva experiences more or less visual feedback depending on whether the gain is high or low. We show that increases and decreases in this gain setting result in adaptive changes in behavior that lead to a generalized decrease or increase of motor output, respectively. Our behavioral analysis shows that both the duration and tail beat frequency of individual swim bouts can be modified, as well as the frequency with which bouts are elicited. These changes can be implemented rapidly, following an exposure to a new gain of just 175 ms. In addition, modifications in some behavioral parameters accumulate over tens of seconds and effects last for at least 30 s from trial to trial. These results suggest that larvae establish an internal representation of the visual feedback expected from a given motor output and that the behavioral modifications are driven by an error signal that arises from the discrepancy between this expectation and the actual visual feedback. The assay we develop presents a unique possibility for studying visuomotor integration using imaging techniques available in the larval zebrafish.

  11. Adaptive Locomotor Behavior in Larval Zebrafish

    PubMed Central

    Portugues, Ruben; Engert, Florian

    2011-01-01

    In this study we report that larval zebrafish display adaptive locomotor output that can be driven by unexpected visual feedback. We develop a new assay that addresses visuomotor integration in restrained larval zebrafish. The assay involves a closed-loop environment in which the visual feedback a larva receives depends on its own motor output in a way that resembles freely swimming conditions. The experimenter can control the gain of this closed feedback loop, so that following a given motor output the larva experiences more or less visual feedback depending on whether the gain is high or low. We show that increases and decreases in this gain setting result in adaptive changes in behavior that lead to a generalized decrease or increase of motor output, respectively. Our behavioral analysis shows that both the duration and tail beat frequency of individual swim bouts can be modified, as well as the frequency with which bouts are elicited. These changes can be implemented rapidly, following an exposure to a new gain of just 175 ms. In addition, modifications in some behavioral parameters accumulate over tens of seconds and effects last for at least 30 s from trial to trial. These results suggest that larvae establish an internal representation of the visual feedback expected from a given motor output and that the behavioral modifications are driven by an error signal that arises from the discrepancy between this expectation and the actual visual feedback. The assay we develop presents a unique possibility for studying visuomotor integration using imaging techniques available in the larval zebrafish. PMID:21909325

  12. Spatial perception and adaptive sonar behavior.

    PubMed

    Aytekin, Murat; Mao, Beatrice; Moss, Cynthia F

    2010-12-01

    Bat echolocation is a dynamic behavior that allows for real-time adaptations in the timing and spectro-temporal design of sonar signals in response to a particular task and environment. To enable detailed, quantitative analyses of adaptive sonar behavior, echolocation call design was investigated in big brown bats, trained to rest on a stationary platform and track a tethered mealworm that approached from a starting distance of about 170 cm in the presence of a stationary sonar distracter. The distracter was presented at different angular offsets and distances from the bat. The results of this study show that the distance and the angular offset of the distracter influence sonar vocalization parameters of the big brown bat, Eptesicus fuscus. Specifically, the bat adjusted its call duration to the closer of two objects, distracter or insect target, and the magnitude of the adjustment depended on the angular offset of the distracter. In contrast, the bat consistently adjusted its call rate to the distance of the insect, even when this target was positioned behind the distracter. The results hold implications for understanding spatial information processing and perception by echolocation.

  13. Adaptive Behavior and Problem Behavior in Young Children with Williams Syndrome

    ERIC Educational Resources Information Center

    Hahn, Laura J.; Fidler, Deborah J.; Hepburn, Susan L.

    2014-01-01

    The present study compares the adaptive behavior profile of 18 young children with Williams syndrome (WS) and a developmentally matched group of 19 children with developmental disabilities and examines the relationship between adaptive behavior and problem behaviors in WS. Parents completed the Vineland Adaptive Behavioral Scales--Interview…

  14. Anomalous human behavior detection: an adaptive approach

    NASA Astrophysics Data System (ADS)

    van Leeuwen, Coen; Halma, Arvid; Schutte, Klamer

    2013-05-01

    Detection of anomalies (outliers or abnormal instances) is an important element in a range of applications such as fault, fraud, suspicious behavior detection and knowledge discovery. In this article we propose a new method for anomaly detection and performed tested its ability to detect anomalous behavior in videos from DARPA's Mind's Eye program, containing a variety of human activities. In this semi-unsupervised task a set of normal instances is provided for training, after which unknown abnormal behavior has to be detected in a test set. The features extracted from the video data have high dimensionality, are sparse and inhomogeneously distributed in the feature space making it a challenging task. Given these characteristics a distance-based method is preferred, but choosing a threshold to classify instances as (ab)normal is non-trivial. Our novel aproach, the Adaptive Outlier Distance (AOD) is able to detect outliers in these conditions based on local distance ratios. The underlying assumption is that the local maximum distance between labeled examples is a good indicator of the variation in that neighborhood, and therefore a local threshold will result in more robust outlier detection. We compare our method to existing state-of-art methods such as the Local Outlier Factor (LOF) and the Local Distance-based Outlier Factor (LDOF). The results of the experiments show that our novel approach improves the quality of the anomaly detection.

  15. Herd behavior in a complex adaptive system

    PubMed Central

    Zhao, Li; Yang, Guang; Wang, Wei; Chen, Yu; Huang, J. P.; Ohashi, Hirotada; Stanley, H. Eugene

    2011-01-01

    In order to survive, self-serving agents in various kinds of complex adaptive systems (CASs) must compete against others for sharing limited resources with biased or unbiased distribution by conducting strategic behaviors. This competition can globally result in the balance of resource allocation. As a result, most of the agents and species can survive well. However, it is a common belief that the formation of a herd in a CAS will cause excess volatility, which can ruin the balance of resource allocation in the CAS. Here this belief is challenged with the results obtained from a modeled resource-allocation system. Based on this system, we designed and conducted a series of computer-aided human experiments including herd behavior. We also performed agent-based simulations and theoretical analyses, in order to confirm the experimental observations and reveal the underlying mechanism. We report that, as long as the ratio of the two resources for allocation is biased enough, the formation of a typically sized herd can help the system to reach the balanced state. This resource ratio also serves as the critical point for a class of phase transition identified herein, which can be used to discover the role change of herd behavior, from a ruinous one to a helpful one. This work is also of value to some fields, ranging from management and social science, to ecology and evolution, and to physics. PMID:21876133

  16. Herd behavior in a complex adaptive system.

    PubMed

    Zhao, Li; Yang, Guang; Wang, Wei; Chen, Yu; Huang, J P; Ohashi, Hirotada; Stanley, H Eugene

    2011-09-13

    In order to survive, self-serving agents in various kinds of complex adaptive systems (CASs) must compete against others for sharing limited resources with biased or unbiased distribution by conducting strategic behaviors. This competition can globally result in the balance of resource allocation. As a result, most of the agents and species can survive well. However, it is a common belief that the formation of a herd in a CAS will cause excess volatility, which can ruin the balance of resource allocation in the CAS. Here this belief is challenged with the results obtained from a modeled resource-allocation system. Based on this system, we designed and conducted a series of computer-aided human experiments including herd behavior. We also performed agent-based simulations and theoretical analyses, in order to confirm the experimental observations and reveal the underlying mechanism. We report that, as long as the ratio of the two resources for allocation is biased enough, the formation of a typically sized herd can help the system to reach the balanced state. This resource ratio also serves as the critical point for a class of phase transition identified herein, which can be used to discover the role change of herd behavior, from a ruinous one to a helpful one. This work is also of value to some fields, ranging from management and social science, to ecology and evolution, and to physics.

  17. Cross-National Assessment of Adaptive Behavior in Three Countries

    ERIC Educational Resources Information Center

    Oakland, Thomas; Iliescu, Dragos; Chen, Hsin-Yi; Chen, Juliet Honglei

    2013-01-01

    Measures of adaptive behaviors provide an important tool in the repertoire of clinical and school/educational psychologists. Measures that assess adaptive behaviors typically have been built in Western cultures and developed in light of behaviors common to them. Nevertheless, these measures are used elsewhere despite a paucity of data that examine…

  18. Adaptive Behavior in Children with Fragile X Syndrome.

    ERIC Educational Resources Information Center

    Hatton, Deborah D.; Wheeler, Anne C.; Skinner, Martie L.; Bailey, Donald B.; Sullivan, Kelly M.; Roberts, Jane E.; Mirrett, Penny; Clark, Renee D.

    2003-01-01

    Adaptive behavior was measured over time in 70 children, ages 1 to 12 years, with fragile X syndrome. With a mean of 4.4 assessments per child, adaptive behavior skills increased steadily and gradually over time. Children with less autistic behavior and higher percentages of the fragile X mental retardation gene protein showed better performance…

  19. Trust-Guided Behavior Adaptation Using Case-Based Reasoning

    DTIC Science & Technology

    2015-08-01

    trustworthiness and adapt its behavior ac- cordingly. As behavior adaptation is performed, us- ing case-based reasoning (CBR), information about the...complete set of rules for trustwor- thy behavior if the robot is expected to handle changes in teammates, environments, or mission contexts. The way

  20. Development and Standardization of the Diagnostic Adaptive Behavior Scale: Application of Item Response Theory to the Assessment of Adaptive Behavior.

    PubMed

    Tassé, Marc J; Schalock, Robert L; Thissen, David; Balboni, Giulia; Bersani, Henry Hank; Borthwick-Duffy, Sharon A; Spreat, Scott; Widaman, Keith F; Zhang, Dalun; Navas, Patricia

    2016-03-01

    The Diagnostic Adaptive Behavior Scale (DABS) was developed using item response theory (IRT) methods and was constructed to provide the most precise and valid adaptive behavior information at or near the cutoff point of making a decision regarding a diagnosis of intellectual disability. The DABS initial item pool consisted of 260 items. Using IRT modeling and a nationally representative standardization sample, the item set was reduced to 75 items that provide the most precise adaptive behavior information at the cutoff area determining the presence or not of significant adaptive behavior deficits across conceptual, social, and practical skills. The standardization of the DABS is described and discussed.

  1. Finite Element Analysis of Adaptive-Stiffening and Shape-Control SMA Hybrid Composites

    NASA Technical Reports Server (NTRS)

    Gao, Xiujie; Burton, Deborah; Turner, Travis L.; Brinson, Catherine

    2005-01-01

    Shape memory alloy hybrid composites with adaptive-stiffening or morphing functions are simulated using finite element analysis. The composite structure is a laminated fiber-polymer composite beam with embedded SMA ribbons at various positions with respect to the neutral axis of the beam. Adaptive stiffening or morphing is activated via selective resistance heating of the SMA ribbons or uniform thermal loads on the beam. The thermomechanical behavior of these composites was simulated in ABAQUS using user-defined SMA elements. The examples demonstrate the usefulness of the methods for the design and simulation of SMA hybrid composites. Keywords: shape memory alloys, Nitinol, ABAQUS, finite element analysis, post-buckling control, shape control, deflection control, adaptive stiffening, morphing, constitutive modeling, user element

  2. Compositional Dictionaries for Domain Adaptive Face Recognition.

    PubMed

    Qiang Qiu; Chellappa, Rama

    2015-12-01

    We present a dictionary learning approach to compensate for the transformation of faces due to the changes in view point, illumination, resolution, and so on. The key idea of our approach is to force domain-invariant sparse coding, i.e., designing a consistent sparse representation of the same face in different domains. In this way, the classifiers trained on the sparse codes in the source domain consisting of frontal faces can be applied to the target domain (consisting of faces in different poses, illumination conditions, and so on) without much loss in recognition accuracy. The approach is to first learn a domain base dictionary, and then describe each domain shift (identity, pose, and illumination) using a sparse representation over the base dictionary. The dictionary adapted to each domain is expressed as the sparse linear combinations of the base dictionary. In the context of face recognition, with the proposed compositional dictionary approach, a face image can be decomposed into sparse representations for a given subject, pose, and illumination. This approach has three advantages. First, the extracted sparse representation for a subject is consistent across domains, and enables pose and illumination insensitive face recognition. Second, sparse representations for pose and illumination can be subsequently used to estimate the pose and illumination condition of a face image. Last, by composing sparse representations for the subject and the different domains, we can also perform pose alignment and illumination normalization. Extensive experiments using two public face data sets are presented to demonstrate the effectiveness of the proposed approach for face recognition.

  3. Communicating to Farmers about Skin Cancer: The Behavior Adaptation Model.

    ERIC Educational Resources Information Center

    Parrott, Roxanne; Monahan, Jennifer; Ainsworth, Stuart; Steiner, Carol

    1998-01-01

    States health campaign messages designed to encourage behavior adaptation have greater likelihood of success than campaigns promoting avoidance of at-risk behaviors that cannot be avoided. Tests a model of health risk behavior using four different behaviors in a communication campaign aimed at reducing farmers' risk for skin cancer--questions…

  4. Investigations on the magnetization behavior of magnetic composite particles

    NASA Astrophysics Data System (ADS)

    Eichholz, Christian; Knoll, Johannes; Lerche, Dietmar; Nirschl, Hermann

    2014-11-01

    In life sciences the application of surface functionalized magnetic composite particles is establishing in diagnostics and in downstream processing of modern biotechnology. These magnetic composite particles consist of non-magnetic material, e.g. polystyrene, which serves as a matrix for the second magnetic component, usually colloidal magnetite. Because of the multitude of magnetic cores these magnetic beads show a complex magnetization behavior which cannot be described with the available approaches for homogeneous magnetic material. Therefore, in this work a new model for the magnetization behavior of magnetic composite particles is developed. By introducing an effective magnetization and considering an overall demagnetization factor the deviation of the demagnetization of homogeneously magnetized particles is taken into account. Calculated and experimental results show a good agreement which allows for the verification of the adapted model of particle magnetization. Besides, a newly developed magnetic analyzing centrifuge is used for the characterization of magnetic composite particle systems. The experimental results, also used for the model verification, give both, information about the magnetic properties and the interaction behavior of particle systems. By adding further components to the particle solution, such as salts or proteins, industrial relevant systems can be reconstructed. The analyzing tool can be used to adapt industrial processes without time-consuming preliminary tests with large samples in the process equipments.

  5. Finite Element Analysis of Adaptive-Stiffening and Shape-Control SMA Hybrid Composites

    NASA Technical Reports Server (NTRS)

    Gao, Xiu-Jie; Turner, Travis L.; Burton, Deborah; Brinson, L. Catherine

    2005-01-01

    The usage of shape memory materials has extended rapidly to many fields, including medical devices, actuators, composites, structures and MEMS devices. For these various applications, shape memory alloys (SMAs) are available in various forms: bulk, wire, ribbon, thin film, and porous. In this work, the focus is on SMA hybrid composites with adaptive-stiffening or morphing functions. These composites are created by using SMA ribbons or wires embedded in a polymeric based composite panel/beam. Adaptive stiffening or morphing is activated via selective resistance heating or uniform thermal loads. To simulate the thermomechanical behavior of these composites, a SMA model was implemented using ABAQUS user element interface and finite element simulations of the systems were studied. Several examples are presented which show that the implemented model can be a very useful design and simulation tool for SMA hybrid composites.

  6. Development and Standardization of the Diagnostic Adaptive Behavior Scale: Application of Item Response Theory to the Assessment of Adaptive Behavior

    ERIC Educational Resources Information Center

    Tassé, Marc J.; Schalock, Robert L.; Thissen, David; Balboni, Giulia; Bersani, Henry, Jr.; Borthwick-Duffy, Sharon A.; Spreat, Scott; Widaman, Keith F.; Zhang, Dalun; Navas, Patricia

    2016-01-01

    The Diagnostic Adaptive Behavior Scale (DABS) was developed using item response theory (IRT) methods and was constructed to provide the most precise and valid adaptive behavior information at or near the cutoff point of making a decision regarding a diagnosis of intellectual disability. The DABS initial item pool consisted of 260 items. Using IRT…

  7. Impact behavior of hydroxyapatite reinforced polyethylene composites.

    PubMed

    Zhang, Y; Tanner, K E

    2003-01-01

    Hydroxyapatite particulate reinforced high density polyethylene composite (HA-HDPE) has been developed as a bone replacement material. The impact behavior of the composites at 37 degrees C has been investigated using an instrumented falling weight impact testing machine. The fracture surfaces were examined using SEM and the fracture mechanisms are discussed. It was found that the fracture toughness of HA-HDPE composites increased with HDPE molecular weight, but decreased with increasing HA volume fraction. Examination of fracture surfaces revealed weak filler/matrix interfaces which can debond easily to enable crack initiation and propagation. Increasing HA volume fraction increases the interface area, and more cracks can form and develop, thus decreasing the impact resistance of the composites. Another important factor for the impact behavior of the composites is the matrix. At higher molecular weight, HDPE is able to sustain more plastic deformation and dissipates more impact energy, hence improving the impact property.

  8. Ceramic matrix composite behavior -- Computational simulation

    SciTech Connect

    Chamis, C.C.; Murthy, P.L.N.; Mital, S.K.

    1996-10-01

    Development of analytical modeling and computational capabilities for the prediction of high temperature ceramic matrix composite behavior has been an ongoing research activity at NASA-Lewis Research Center. These research activities have resulted in the development of micromechanics based methodologies to evaluate different aspects of ceramic matrix composite behavior. The basis of the approach is micromechanics together with a unique fiber substructuring concept. In this new concept the conventional unit cell (the smallest representative volume element of the composite) of micromechanics approach has been modified by substructuring the unit cell into several slices and developing the micromechanics based equations at the slice level. Main advantage of this technique is that it can provide a much greater detail in the response of composite behavior as compared to a conventional micromechanics based analysis and still maintains a very high computational efficiency. This methodology has recently been extended to model plain weave ceramic composites. The objective of the present paper is to describe the important features of the modeling and simulation and illustrate with select examples of laminated as well as woven composites.

  9. Panel V: Adaptive Health Behaviors Among Ethnic Minorities

    PubMed Central

    Bagley, Shirley P.; Angel, Ronald; Dilworth-Anderson, Peggye; Liu, William; Schinke, Steven

    2006-01-01

    Race, ethnicity, and cultural attitudes and practices are among the variables that influence health behaviors, including adaptive health behaviors. The following discussions highlight the important role of social conditions in shaping health behaviors and the central role of family in promoting health across the Asian, Hispanic, Native American, and African American ethnic groups. Factors that may lead to health-damaging behaviors are also discussed. The need for additional research that identifies correlations among physiological, social, and behavioral factors and health behaviors, as well as underlying mechanisms, is called for. PMID:8654341

  10. Hysteretic behavior of soft magnetic elastomer composites

    NASA Astrophysics Data System (ADS)

    Krautz, Maria; Werner, David; Schrödner, Mario; Funk, Alexander; Jantz, Alexander; Popp, Jana; Eckert, Jürgen; Waske, Anja

    2017-03-01

    Composites of polymer and micron-sized particles of carbonyl-iron were investigated in terms of their magnetization behavior. Thermoplastic elastomers with varying Young's modulus (EPolymer=0.14-14.6 MPa) were used as matrix material. Field dependent magnetization curves reveal that the hysteretic behavior of the composites strongly depends on both the particle fraction (7, 10, 14, 21, 31 vol%) and on the mechanical properties of the polymer. It is shown that hysteresis only appears above a certain fraction of magnetic particles which can be accounted to the magnetic exchange between the particles. However, hysteresis is suppressed in the composite with largest Young's modulus of the polymer matrix, even at largest particle fraction.

  11. Adapting Behavioral Interventions for Social Media Delivery

    PubMed Central

    Waring, Molly E; May, Christine N; Ding, Eric Y; Kunz, Werner H; Hayes, Rashelle; Oleski, Jessica L

    2016-01-01

    Patients are increasingly using online social networks (ie, social media) to connect with other patients and health care professionals—a trend called peer-to-peer health care. Because online social networks provide a means for health care professionals to communicate with patients, and for patients to communicate with each other, an opportunity exists to use social media as a modality to deliver behavioral interventions. Social media-delivered behavioral interventions have the potential to reduce the expense of behavioral interventions by eliminating visits, as well as increase our access to patients by becoming embedded in their social media feeds. Trials of online social network-delivered behavioral interventions have shown promise, but much is unknown about intervention development and methodology. In this paper, we discuss the process by which investigators can translate behavioral interventions for social media delivery. We present a model that describes the steps and decision points in this process, including the necessary training and reporting requirements. We also discuss issues pertinent to social media-delivered interventions, including cost, scalability, and privacy. Finally, we identify areas of research that are needed to optimize this emerging behavioral intervention modality. PMID:26825969

  12. Adapting Behavioral Interventions for Social Media Delivery.

    PubMed

    Pagoto, Sherry; Waring, Molly E; May, Christine N; Ding, Eric Y; Kunz, Werner H; Hayes, Rashelle; Oleski, Jessica L

    2016-01-29

    Patients are increasingly using online social networks (ie, social media) to connect with other patients and health care professionals--a trend called peer-to-peer health care. Because online social networks provide a means for health care professionals to communicate with patients, and for patients to communicate with each other, an opportunity exists to use social media as a modality to deliver behavioral interventions. Social media-delivered behavioral interventions have the potential to reduce the expense of behavioral interventions by eliminating visits, as well as increase our access to patients by becoming embedded in their social media feeds. Trials of online social network-delivered behavioral interventions have shown promise, but much is unknown about intervention development and methodology. In this paper, we discuss the process by which investigators can translate behavioral interventions for social media delivery. We present a model that describes the steps and decision points in this process, including the necessary training and reporting requirements. We also discuss issues pertinent to social media-delivered interventions, including cost, scalability, and privacy. Finally, we identify areas of research that are needed to optimize this emerging behavioral intervention modality.

  13. Offsetting Behavior and Adaptation: How Students Respond to Hard Professors

    ERIC Educational Resources Information Center

    Stanley, Laura E.; Delmontagne, Emma M.; Wood, William C.

    2016-01-01

    Do students engage in offsetting behavior, adapting their study effort to the difficulty of learning? The authors present the results of survey research intended to test for the presence of offsetting behavior at a regional university. Instead of trying to determine whether students study less when learning is easier, we check to see whether…

  14. Leadership Behaviors of Management for Complex Adaptive Systems

    DTIC Science & Technology

    2010-04-01

    2010 Northrop Grumman 14 Manager Leadership Behaviors of Managers Visionary Leadership Motivates and Encourages Promotes Organizational Learning Behaviors...most © Copyright 2009 Northrop GrummanCopyright 2010 Northrop Grumman 19 vulnerable? The Manager: Promotes Organizational Learning • Promotes...emphasize collaboration, team empowerment, trust, and organizational learning • Train managers in the practices that works best in adaptive environments

  15. Cultural Adaptations of Behavioral Health Interventions: A Progress Report

    ERIC Educational Resources Information Center

    Barrera, Manuel, Jr.; Castro, Felipe G.; Strycker, Lisa A.; Toobert, Deborah J.

    2013-01-01

    Objective: To reduce health disparities, behavioral health interventions must reach subcultural groups and demonstrate effectiveness in improving their health behaviors and outcomes. One approach to developing such health interventions is to culturally adapt original evidence-based interventions. The goals of the article are to (a) describe…

  16. High Strain Rate Behavior of Polyurea Compositions

    NASA Astrophysics Data System (ADS)

    Joshi, Vasant; Milby, Christopher

    2011-06-01

    Polyurea has been gaining importance in recent years due to its impact resistance properties. The actual compositions of this viscoelastic material must be tailored for specific use. It is therefore imperative to study the effect of variations in composition on the properties of the material. High-strain-rate response of three polyurea compositions with varying molecular weights has been investigated using a Split Hopkinson Pressure Bar arrangement equipped with titanium bars. The polyurea compositions were synthesized from polyamines (Versalink, Air Products) with a multi-functional isocyanate (Isonate 143L, Dow Chemical). Amines with molecular weights of 1000, 650, and a blend of 250/1000 have been used in the current investigation. The materials have been tested up to strain rates of 6000/s. Results from these tests have shown interesting trends on the high rate behavior. While higher molecular weight composition show lower yield, they do not show dominant hardening behavior. On the other hand, the blend of 250/1000 show higher load bearing capability but lower strain hardening effects than the 600 and 1000 molecular weight amine based materials. Refinement in experimental methods and comparison of results using aluminum Split Hopkinson Bar is presented.

  17. Prediction of composite thermal behavior made simple

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.

    1981-01-01

    A convenient procedure is described to determine the thermal behavior (thermal expansion coefficients and thermal stresses) of angleplied fiber composites using a pocket calculator. The procedure consists of equations and appropriate graphs for various ( + or - theta) ply combinations. These graphs present reduced stiffness and thermal expansion coefficients as functions of (+ or - theta) in order to simplify and expedite the use of the equations. The procedure is applicable to all types of balanced, symmetric fiber composites including interply and intraply hybrids. The versatility and generality of the procedure is illustrated using several step-by-step numerical examples.

  18. Mouse Behavior: Conjectures about Adaptations for Survival.

    ERIC Educational Resources Information Center

    Rop, Charles

    2001-01-01

    Presents an experiment on mouse behavior in which students learn to observe, pay attention to details, record field notes, and ask questions about their observations. Uses a white mouse to eliminate the risk of disease that a wild rodent might carry. Lists materials, set up, and procedure. (YDS)

  19. Building team adaptive capacity: the roles of sensegiving and team composition.

    PubMed

    Randall, Kenneth R; Resick, Christian J; DeChurch, Leslie A

    2011-05-01

    The current study draws on motivated information processing in groups theory to propose that leadership functions and composition characteristics provide teams with the epistemic and social motivation needed for collective information processing and strategy adaptation. Three-person teams performed a city management decision-making simulation (N=74 teams; 222 individuals). Teams first managed a simulated city that was newly formed and required growth strategies and were then abruptly switched to a second simulated city that was established and required revitalization strategies. Consistent with hypotheses, external sensegiving and team composition enabled distinct aspects of collective information processing. Sensegiving prompted the emergence of team strategy mental models (i.e., cognitive information processing); psychological collectivism facilitated information sharing (i.e., behavioral information processing); and cognitive ability provided the capacity for both the cognitive and behavioral aspects of collective information processing. In turn, team mental models and information sharing enabled reactive strategy adaptation.

  20. Linking Individual and Collective Behavior in Adaptive Social Networks

    NASA Astrophysics Data System (ADS)

    Pinheiro, Flávio L.; Santos, Francisco C.; Pacheco, Jorge M.

    2016-03-01

    Adaptive social structures are known to promote the evolution of cooperation. However, up to now the characterization of the collective, population-wide dynamics resulting from the self-organization of individual strategies on a coevolving, adaptive network has remained unfeasible. Here we establish a (reversible) link between individual (micro)behavior and collective (macro)behavior for coevolutionary processes. We demonstrate that an adaptive network transforms a two-person social dilemma locally faced by individuals into a collective dynamics that resembles that associated with an N -person coordination game, whose characterization depends sensitively on the relative time scales between the entangled behavioral and network evolutions. In particular, we show that the faster the relative rate of adaptation of the network, the smaller the critical fraction of cooperators required for cooperation to prevail, thus establishing a direct link between network adaptation and the evolution of cooperation. The framework developed here is general and may be readily applied to other dynamical processes occurring on adaptive networks, notably, the spreading of contagious diseases or the diffusion of innovations.

  1. Coupled multi-disciplinary composites behavior simulation

    NASA Technical Reports Server (NTRS)

    Singhal, Surendra N.; Murthy, Pappu L. N.; Chamis, Christos C.

    1993-01-01

    The capabilities of the computer code CSTEM (Coupled Structural/Thermal/Electro-Magnetic Analysis) are discussed and demonstrated. CSTEM computationally simulates the coupled response of layered multi-material composite structures subjected to simultaneous thermal, structural, vibration, acoustic, and electromagnetic loads and includes the effect of aggressive environments. The composite material behavior and structural response is determined at its various inherent scales: constituents (fiber/matrix), ply, laminate, and structural component. The thermal and mechanical properties of the constituents are considered to be nonlinearly dependent on various parameters such as temperature and moisture. The acoustic and electromagnetic properties also include dependence on vibration and electromagnetic wave frequencies, respectively. The simulation is based on a three dimensional finite element analysis in conjunction with composite mechanics and with structural tailoring codes, and with acoustic and electromagnetic analysis methods. An aircraft engine composite fan blade is selected as a typical structural component to demonstrate the CSTEM capabilities. Results of various coupled multi-disciplinary heat transfer, structural, vibration, acoustic, and electromagnetic analyses for temperature distribution, stress and displacement response, deformed shape, vibration frequencies, mode shapes, acoustic noise, and electromagnetic reflection from the fan blade are discussed for their coupled effects in hot and humid environments. Collectively, these results demonstrate the effectiveness of the CSTEM code in capturing the coupled effects on the various responses of composite structures subjected to simultaneous multiple real-life loads.

  2. Behavioral and neural Darwinism: selectionist function and mechanism in adaptive behavior dynamics.

    PubMed

    McDowell, J J

    2010-05-01

    An evolutionary theory of behavior dynamics and a theory of neuronal group selection share a common selectionist framework. The theory of behavior dynamics instantiates abstractly the idea that behavior is selected by its consequences. It implements Darwinian principles of selection, reproduction, and mutation to generate adaptive behavior in virtual organisms. The behavior generated by the theory has been shown to be quantitatively indistinguishable from that of live organisms. The theory of neuronal group selection suggests a mechanism whereby the abstract principles of the evolutionary theory may be implemented in the nervous systems of biological organisms. According to this theory, groups of neurons subserving behavior may be selected by synaptic modifications that occur when the consequences of behavior activate value systems in the brain. Together, these theories constitute a framework for a comprehensive account of adaptive behavior that extends from brain function to the behavior of whole organisms in quantitative detail.

  3. Optimization of Adaptive Intraply Hybrid Fiber Composites with Reliability Considerations

    NASA Technical Reports Server (NTRS)

    Shiao, Michael C.; Chamis, Christos C.

    1994-01-01

    The reliability with bounded distribution parameters (mean, standard deviation) was maximized and the reliability-based cost was minimized for adaptive intra-ply hybrid fiber composites by using a probabilistic method. The probabilistic method accounts for all naturally occurring uncertainties including those in constituent material properties, fabrication variables, structure geometry, and control-related parameters. Probabilistic sensitivity factors were computed and used in the optimization procedures. For actuated change in the angle of attack of an airfoil-like composite shell structure with an adaptive torque plate, the reliability was maximized to 0.9999 probability, with constraints on the mean and standard deviation of the actuation material volume ratio (percentage of actuation composite material in a ply) and the actuation strain coefficient. The reliability-based cost was minimized for an airfoil-like composite shell structure with an adaptive skin and a mean actuation material volume ratio as the design parameter. At a O.9-mean actuation material volume ratio, the minimum cost was obtained.

  4. Compression behavior of unidirectional fibrous composite

    NASA Technical Reports Server (NTRS)

    Sinclair, J. H.; Chamis, C. C.

    1982-01-01

    The longitudinal compression behavior of unidirectional fiber composites is investigated using a modified Celanese test method with thick and thin test specimens. The test data obtained are interpreted using the stress/strain curves from back-to-back strain gages, examination of fracture surfaces by scanning electron microscope, and predictive equations for distinct failure modes including fiber compression failure, Euler buckling, delamination, and flexure. The results show that the longitudinal compression fracture is induced by a combination of delamination, flexure, and fiber tier breaks. No distinct fracture surface characteristics can be associated with unique failure modes. An equation is described which can be used to extract the longitudinal compression strength knowing the longitudinal tensile and flexural strengths of the same composite system.

  5. Structural behavior of composites with progressive fracture

    NASA Technical Reports Server (NTRS)

    Minnetyan, Levon; Chamis, Christos C.; Murthy, Pappu L. N.

    1990-01-01

    Structural characteristics such as natural frequencies and buckling loads with corresponding mode shapes were investigated during progressive fracture of multilayer, angle-plied polymer matrix composites. A computer program was used to generate the numerical results for overall mechanical response of damaged composites. Variations in structural characteristics as a function of the previously applied loading were studied. Results indicate that most of the overall structural properties were preserved throughout a significant proportion of the ultimate fracture load. For the cases studied, changes in structural behavior began to occur after 70 percent of the ultimate fracture load was applied. However, the individual nature of the structural change was rather varied depending on the laminate configuration, fiber orientation, and the boundary conditions.

  6. Endogenous Nuclear RNAi Mediates Behavioral Adaptation to Odor

    PubMed Central

    Juang, Bi-Tzen; Gu, Chen; Starnes, Linda; Palladino, Francesca; Goga, Andrei; Kennedy, Scott; L'Etoile, Noelle D.

    2014-01-01

    Summary Most eukaryotic cells express small regulatory RNAs. The purpose of one class, the somatic endogenous siRNAs (endo-siRNAs) remains unclear. Here we show the endo-siRNA pathway promotes odor adaptation in C. elegans AWC olfactory neurons. In adaptation, the nuclear Argonaute NRDE-3, which acts in AWC, is loaded with siRNAs targeting odr-1, a gene who's down regulation is required for adaptation. Concomitant with increased odr-1 siRNA in AWC, we observe increased binding of the HP1 homolog HPL-2 at the odr-1 locus in AWC and reduced odr-1 mRNA in adapted animals. Phosphorylation of HPL-2, an in vitro substrate of the EGL-4 kinase that promotes adaption, is necessary and sufficient for behavioral adaptation. Thus, environmental stimulation amplifies an endo-siRNA negative feedback loop to dynamically repress cognate gene expression and shape behavior. This class of siRNA may act broadly as a rheostat allowing prolonged stimulation to dampen gene expression and promote cellular memory formation. PMID:23993094

  7. Sensory Processing Subtypes in Autism: Association with Adaptive Behavior

    ERIC Educational Resources Information Center

    Lane, Alison E.; Young, Robyn L.; Baker, Amy E. Z.; Angley, Manya T.

    2010-01-01

    Children with autism are frequently observed to experience difficulties in sensory processing. This study examined specific patterns of sensory processing in 54 children with autistic disorder and their association with adaptive behavior. Model-based cluster analysis revealed three distinct sensory processing subtypes in autism. These subtypes…

  8. Amyotrophic Lateral Sclerosis: An Introduction to Psychosocial and Behavioral Adaptations.

    ERIC Educational Resources Information Center

    Hoffman, R. Leigh; Decker, Thomas W.

    1993-01-01

    Defines amyotrophic lateral sclerosis (ALS) as motor-neuron disease that is terminal. Discusses symptoms associated with ALS and identifies treatment options. Reviews psychological and behavioral adaptations in regard to ALS clients, their families, and professionals who work with them. Discusses support groups as method of reducing stress for ALS…

  9. Coping with Information Overload as Adaptive Behavior in Competitive Debate.

    ERIC Educational Resources Information Center

    Dudczak, Craig A.

    When the amount of available information exceeds the ability of the user to process it, "information overload" is created. In an attempt to maintain some control over the quantity of arguments they may face, debaters have developed adaptive behavior, primarily through the generic argument--any argument within a "deliverative"…

  10. Adaptive Behavior in Toddlers under Two with Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Paul, Rhea; Loomis, Rebecca; Chawarska, Katarzyna

    2014-01-01

    The Vineland Adaptive Behavior Scale was administered to 54 children diagnosed with autism spectrum disorder (ASD) before age 2, and a matching group of 18 toddlers with developmental delay (DD). The group with ASD was more impaired on all scales of the Vineland than DD peers. When 18 ASD/DD pairs very closely matched on age, verbal and nonverbal…

  11. Marginal adaptation of composite resins under two adhesive techniques.

    PubMed

    Dačić, Stefan; Veselinović, Aleksandar M; Mitić, Aleksandar; Nikolić, Marija; Cenić, Milica; Dačić-Simonović, Dragica

    2016-11-01

    In the present research, different adhesive techniques were used to set up fillings with composite resins. After the application of etch and rinse or self etch adhesive technique, marginal adaptation of composite fillings was estimated by the length of margins without gaps, and by the microretention of resin in enamel and dentin. The study material consisted of 40 extracted teeth. Twenty Class V cavities were treated with 35% phosphorous acid and restored after rinsing by Adper Single Bond 2 and Filtek Ultimate-ASB/FU 3M ESPE composite system. The remaining 20 cavities were restored by Adper Easy One-AEO/FU 3M ESPE composite system. Marginal adaptation of composite fillings was examined using a scanning electron microscope (SEM). The etch and rinse adhesive technique showed a significantly higher percentage of margin length without gaps (in enamel: 92.5%, in dentin: 57.3%), compared with the self-etch technique with lower percentage of margin length without gaps, in enamel 70.4% (p < .001), and in dentin-22.6% (p < .05). In the first technique, microretention was composed of adhesive and hybrid layers as well as resin tugs in interprismatic spaces of enamel, while the dentin microretention was composed of adhesive and hybrid layers with resin tugs in dentin canals. In the second technique, resin tugs were rarely seen and a microgap was dominant along the border of restoration margins. The SEM analysis showed a better marginal adaptation of composite resin to enamel and dentin with better microretention when the etch and rinse adhesive procedure was applied.

  12. Nutrients affecting brain composition and behavior

    NASA Technical Reports Server (NTRS)

    Wurtman, R. J.

    1987-01-01

    This review examines the changes in brain composition and in various brain functions, including behavior, that can follow the ingestion of particular foods or nutrients. It details those that are best understood: the increases in serotonin, catecholamine, or acetylcholine synthesis that can occur subsequent to food-induced increases in brain levels of tryptophan, tyrosine, or choline; it also discusses the various processes that must intervene between the mouth and the synapse, so to speak, in order for a nutrient to affect neurotransmission, and it speculates as to additional brain chemicals that may ultimately be found to be affected by changes in the availability of their nutrient precursors. Because the brain chemicals best known to be nutrient dependent overlap with those thought to underlie the actions of most of the drugs used to treat psychiatric diseases, knowledge of this dependence may help the psychiatrist to understand some of the pathologic processes occurring in his/her patients, particularly those with appetitive symptoms. At the very least, such knowledge should provide the psychiatrist with objective criteria for judging when to take seriously assertions that particular foods or nutrients do indeed affect behavior (e.g., in hyperactive children). If the food can be shown to alter neurotransmitter release, it may be behaviorally-active; however, if it lacks a discernible neurochemical effect, the likelihood that it really alters behavior is small.

  13. Shaping Embodied Neural Networks for Adaptive Goal-directed Behavior

    PubMed Central

    Chao, Zenas C.; Bakkum, Douglas J.; Potter, Steve M.

    2008-01-01

    The acts of learning and memory are thought to emerge from the modifications of synaptic connections between neurons, as guided by sensory feedback during behavior. However, much is unknown about how such synaptic processes can sculpt and are sculpted by neuronal population dynamics and an interaction with the environment. Here, we embodied a simulated network, inspired by dissociated cortical neuronal cultures, with an artificial animal (an animat) through a sensory-motor loop consisting of structured stimuli, detailed activity metrics incorporating spatial information, and an adaptive training algorithm that takes advantage of spike timing dependent plasticity. By using our design, we demonstrated that the network was capable of learning associations between multiple sensory inputs and motor outputs, and the animat was able to adapt to a new sensory mapping to restore its goal behavior: move toward and stay within a user-defined area. We further showed that successful learning required proper selections of stimuli to encode sensory inputs and a variety of training stimuli with adaptive selection contingent on the animat's behavior. We also found that an individual network had the flexibility to achieve different multi-task goals, and the same goal behavior could be exhibited with different sets of network synaptic strengths. While lacking the characteristic layered structure of in vivo cortical tissue, the biologically inspired simulated networks could tune their activity in behaviorally relevant manners, demonstrating that leaky integrate-and-fire neural networks have an innate ability to process information. This closed-loop hybrid system is a useful tool to study the network properties intermediating synaptic plasticity and behavioral adaptation. The training algorithm provides a stepping stone towards designing future control systems, whether with artificial neural networks or biological animats themselves. PMID:18369432

  14. High strain rate behavior of polyurea compositions

    NASA Astrophysics Data System (ADS)

    Joshi, Vasant S.; Milby, Christopher

    2012-03-01

    High-strain-rate response of three polyurea compositions with varying molecular weights has been investigated using a Split Hopkinson Pressure Bar arrangement equipped with aluminum bars. Three polyurea compositions were synthesized from polyamines (Versalink, Air Products) with a multi-functional isocyanate (Isonate 143L, Dow Chemical). Amines with molecular weights of 1000, 650, and a blend of 250/1000 have been used in the current investigation. These materials have been tested to strain rates of over 6000/s. High strain rate results from these tests have shown varying trends as a function of increasing strain. While higher molecular weight composition show lower yield, they do not show dominant hardening behavior at lower strain. On the other hand, the blend of 250/1000 show higher load bearing capability but lower strain hardening effects than the 600 and 1000 molecular weight amine based materials. Results indicate that the initial increase in the modulus of the blend of 250/1000 may lead to the loss of strain hardening characteristics as the material is compressed to 50% strain, compared to 1000 molecular weight amine based material.

  15. Mechanical behavior of carbon-carbon composites

    NASA Technical Reports Server (NTRS)

    Rozak, G. A.

    1984-01-01

    A general background, test plan, and some results of preliminary examinations of a carbon-carbon composite material are presented with emphasis on mechanical testing and inspection techniques. Experience with testing and evaluation was gained through tests of a low modulus carbon-carbon material, K-Karb C. The properties examined are the density - 1.55 g/cc; four point flexure strength in the warp - 137 MPa (19,800 psi) and the fill - 95.1 MPa (13,800 psi,) directions; and the warp interlaminar shear strength - 14.5 MPa (2100 psi). Radiographic evaluation revealed thickness variations and the thinner areas of the composite were scrapped. The ultrasonic C-scan showed attenuation variations, but these did not correspond to any of the physical and mechanical properties measured. Based on these initial tests and a survey of the literature, a plan has been devised to examine the effect of stress on the oxidation behavior, and the strength degradation of coated carbon-carbon composites. This plan will focus on static fatigue tests in the four point flexure mode in an elevated temperature, oxidizing environment.

  16. Cognitive and Adaptive Behavior Outcomes of Behavioral Intervention for Young Children with Intellectual Disability

    ERIC Educational Resources Information Center

    Eldevik, Sigmund; Jahr, Erik; Eikeseth, Svein; Hastings, Richard P.; Hughes, Carl J.

    2010-01-01

    Data from Norway were analyzed to evaluate early behavioral intervention for children with intellectual disabilities. The intervention group (n = 11) received approximately 10 hours per week of behavioral intervention; the eclectic comparison group (n = 14) received treatment as usual. After 1 year, changes in intelligence and adaptive behavior…

  17. Thermomechanical behavior of shape memory elastomeric composites

    NASA Astrophysics Data System (ADS)

    Ge, Qi; Luo, Xiaofan; Rodriguez, Erika D.; Zhang, Xiao; Mather, Patrick T.; Dunn, Martin L.; Qi, H. Jerry

    2012-01-01

    Shape memory polymers (SMPs) can fix a temporary shape and recover their permanent shape in response to environmental stimuli such as heat, electricity, or irradiation. Most thermally activated SMPs use the macromolecular chain mobility change around the glass transition temperature ( Tg) to achieve the shape memory (SM) effects. During this process, the stiffness of the material typically changes by three orders of magnitude. Recently, a composite materials approach was developed to achieve thermally activated shape memory effect where the material exhibits elastomeric response in both the temporary and the recovered configurations. These shape memory elastomeric composites (SMECs) consist of an elastomeric matrix reinforced by a semicrystalline polymer fiber network. The matrix provides background rubber elasticity while the fiber network can transform between solid crystals and melt phases over the operative temperature range. As such it serves as a reversible "switching phase" that enables shape fixing and recovery. Shape memory elastomeric composites provide a new paradigm for the development of a wide array of active polymer composites that utilize the melt-crystal transition to achieve the shape memory effect. This potentially allows for material systems with much simpler chemistries than most shape memory polymers and thus can facilitate more rapid material development and insertion. It is therefore important to understand the thermomechanical behavior and to develop corresponding material models. In this paper, a 3D finite-deformation constitutive modeling framework was developed to describe the thermomechanical behavior of SMEC. The model is phenomenological, although inspired by micromechanical considerations of load transfer between the matrix and fiber phases of a composite system. It treats the matrix as an elastomer and the fibers as a complex solid that itself is an aggregate of melt and crystal phases that evolve from one to the other during a

  18. Geometry adaptive control of a composite reflector using PZT actuator

    NASA Astrophysics Data System (ADS)

    Lan, Lan; Jiang, Shuidong; Zhou, Yang; Fang, Houfei; Tan, Shujun; Wu, Zhigang

    2015-04-01

    Maintaining geometrical high precision for a graphite fiber reinforced composite (GFRC) reflector is a challenging task. Although great efforts have been placed to improve the fabrication precision, geometry adaptive control for a reflector is becoming more and more necessary. This paper studied geometry adaptive control for a GFRC reflector with piezoelectric ceramic transducer (PZT) actuators assembled on the ribs. In order to model the piezoelectric effect in finite element analysis (FEA), a thermal analogy was used in which the temperature was applied to simulate the actuation voltage, and the piezoelectric constant was mimicked by a Coefficient of Thermal Expansion (CTE). PZT actuator's equivalent model was validated by an experiment. The deformations of a triangular GFRC specimen with three PZT actuators were also measured experimentally and compared with that of simulation. This study developed a multidisciplinary analytical model, which includes the composite structure, thermal, thermal deformation and control system, to perform an optimization analysis and design for the adaptive GFRC reflector by considering the free vibration, gravity deformation and geometry controllability.

  19. Information theory of adaptation in neurons, behavior, and mood

    PubMed Central

    Sharpee, Tatyana O.; Calhoun, Adam J.; Chalasani, Sreekanth H.

    2014-01-01

    The ability to make accurate predictions of future stimuli and consequences of one’s actions are crucial for the survival and appropriate decision-making. These predictions are constantly being made at different levels of the nervous system. This is evidenced by adaptation to stimulus parameters in sensory coding, and in learning of an up-to-date model of the environment at the behavioral level. This review will discuss recent findings that actions of neurons and animals are selected based on detailed stimulus history in such a way as to maximize information for achieving the task at hand. Information maximization dictates not only how sensory coding should adapt to various statistical aspects of stimuli, but also that reward function should adapt to match the predictive information from past to future. PMID:24709600

  20. Biologically-inspired adaptive obstacle negotiation behavior of hexapod robots.

    PubMed

    Goldschmidt, Dennis; Wörgötter, Florentin; Manoonpong, Poramate

    2014-01-01

    Neurobiological studies have shown that insects are able to adapt leg movements and posture for obstacle negotiation in changing environments. Moreover, the distance to an obstacle where an insect begins to climb is found to be a major parameter for successful obstacle negotiation. Inspired by these findings, we present an adaptive neural control mechanism for obstacle negotiation behavior in hexapod robots. It combines locomotion control, backbone joint control, local leg reflexes, and neural learning. While the first three components generate locomotion including walking and climbing, the neural learning mechanism allows the robot to adapt its behavior for obstacle negotiation with respect to changing conditions, e.g., variable obstacle heights and different walking gaits. By successfully learning the association of an early, predictive signal (conditioned stimulus, CS) and a late, reflex signal (unconditioned stimulus, UCS), both provided by ultrasonic sensors at the front of the robot, the robot can autonomously find an appropriate distance from an obstacle to initiate climbing. The adaptive neural control was developed and tested first on a physical robot simulation, and was then successfully transferred to a real hexapod robot, called AMOS II. The results show that the robot can efficiently negotiate obstacles with a height up to 85% of the robot's leg length in simulation and 75% in a real environment.

  1. On fractional order composite model reference adaptive control

    NASA Astrophysics Data System (ADS)

    Wei, Yiheng; Sun, Zhenyuan; Hu, Yangsheng; Wang, Yong

    2016-08-01

    This paper presents a novel composite model reference adaptive control approach for a class of fractional order linear systems with unknown constant parameters. The method is extended from the model reference adaptive control. The parameter estimation error of our method depends on both the tracking error and the prediction error, whereas the existing method only depends on the tracking error, which makes our method has better transient performance in the sense of generating smooth system output. By the aid of the continuous frequency distributed model, stability of the proposed approach is established in the Lyapunov sense. Furthermore, the convergence property of the model parameters estimation is presented, on the premise that the closed-loop control system is stable. Finally, numerical simulation examples are given to demonstrate the effectiveness of the proposed schemes.

  2. Compression behavior of delaminated composite plates

    NASA Technical Reports Server (NTRS)

    Peck, Scott O.; Springer, George S.

    1989-01-01

    The response of delaminated composite plates to compressive in-plane loads was investigated. The delaminated region may be either circular or elliptical, and may be located between any two plies of the laminate. For elliptical delaminations, the axes of the ellipse may be arbitrarily oriented with respect to the applied loads. A model was developed that describes the stresses, strains, and deformation of the sublaminate created by the delamination. The mathematical model is based on a two dimensional nonlinear plate theory that includes the effects of transverse shear deformation. The model takes into account thermal and moisture induced strains, transverse pressures acting on the sublaminate, and contact between the sublaminate and plate. The solution technique used is the Ritz method. A computationally efficient computer implementation of the model was developed. The code can be used to predict the nonlinear-load-strain behavior of the sublaminate including the buckling load, postbuckling behavior, and the onset of delamination growth. The accuracy of the code was evaluated by comparing the model results to benchmark analytical solutions. A series of experiments was conducted on Fiberite T300/976 graphite/epoxy laminates bonded to an aluminum honeycomb core forming a sandwich panel. Either circles or ellipses made from Teflon film were embedded in the laminates, simulating the presence of a delamination. Each specimen was loaded in compression and the strain history of the sublaminate was recorded far into the postbuckling regime. The extent of delamination growth was evaluated by C-scan examination of each specimen. The experimental data were compared to code predictions. The code was found to describe the data with reasonable accuracy. A sensitivity study examined the relative importance of various material properties, the delamination dimensions, the contact model, the transverse pressure differential, the critical strain energy release rate, and the relative

  3. Behavioral training promotes multiple adaptive processes following acute hearing loss

    PubMed Central

    Keating, Peter; Rosenior-Patten, Onayomi; Dahmen, Johannes C; Bell, Olivia; King, Andrew J

    2016-01-01

    The brain possesses a remarkable capacity to compensate for changes in inputs resulting from a range of sensory impairments. Developmental studies of sound localization have shown that adaptation to asymmetric hearing loss can be achieved either by reinterpreting altered spatial cues or by relying more on those cues that remain intact. Adaptation to monaural deprivation in adulthood is also possible, but appears to lack such flexibility. Here we show, however, that appropriate behavioral training enables monaurally-deprived adult humans to exploit both of these adaptive processes. Moreover, cortical recordings in ferrets reared with asymmetric hearing loss suggest that these forms of plasticity have distinct neural substrates. An ability to adapt to asymmetric hearing loss using multiple adaptive processes is therefore shared by different species and may persist throughout the lifespan. This highlights the fundamental flexibility of neural systems, and may also point toward novel therapeutic strategies for treating sensory disorders. DOI: http://dx.doi.org/10.7554/eLife.12264.001 PMID:27008181

  4. Reliability and Validity of the Vietnamese Vineland Adaptive Behavior Scales with Preschool-Age Children

    ERIC Educational Resources Information Center

    Goldberg, Michael R.; Dill, Charles A.; Shin, Jin Y.; Nhan, Nguyen Viet

    2009-01-01

    This study was conducted to examine an adaptation of the Vineland Adaptive Behavior Scale (VABS) [Sparrow, S. S., Balla, D. A., & Cicchetti, D. V. (1984). "The Vineland Adaptive Behavior Scales." Circle Pines, MN: America Guidance Service; Sparrow, S. S., Balla, D. A., & Cicchetti, D. V. (2005). "Vineland Adaptive Behavior…

  5. Brief Report: Examination of Correlates of Adaptive Behavior in Children with HFASD using the BASC-2 Parent Rating Scale.

    PubMed

    McDonald, Christin A; Donnelly, James P; Rodgers, Jonathan D; Thomeer, Marcus L; Lopata, Christopher; Jordan, Allyson K

    2017-02-10

    This study extended the research on correlates of adaptive functioning of high-functioning children with autism spectrum disorder (HFASD) using the Behavior Assessment System for Children-Second Edition (BASC-2). Specifically, this study investigated the relationships between adaptive behavior and age, IQ, and ASD symptomology, in a well-characterized sample of 119 children with HFASD, ages 6-11 years. Results revealed age and IQ were not significantly correlated with adaptive ability. However, total autism symptoms [measured by the Autism Diagnostic Interview-Revised (ADI-R)], as well as ASD-social symptoms were negatively correlated with adaptive ability. Mean comparisons revealed that participants falling into the clinically-significant range of the BASC-2 Adaptive Skills Composite (ASC) displayed significantly greater levels of both overall and social ASD symptoms.

  6. Material Composite Behavior Under High-Pressure

    NASA Astrophysics Data System (ADS)

    Conil, N.; Kavner, A.

    2004-12-01

    ; fibers and matrix pressures are almost the same (not more than 0.6 GPa in difference in our experiments). In addition, we present finite element modeling of behavior of composite materials in the diamond cell sample chamber that are in excellent agreement with experiments results. With this study we show that the geometry of samples in the diamond cell must be understood in order to properly interpret measurements. Our ultimate goal is to use this information to design samples that are optimized for better measurements of rheological behavior of Earth interior materials.

  7. Adaptive neural coding: from biological to behavioral decision-making

    PubMed Central

    Louie, Kenway; Glimcher, Paul W.; Webb, Ryan

    2015-01-01

    Empirical decision-making in diverse species deviates from the predictions of normative choice theory, but why such suboptimal behavior occurs is unknown. Here, we propose that deviations from optimality arise from biological decision mechanisms that have evolved to maximize choice performance within intrinsic biophysical constraints. Sensory processing utilizes specific computations such as divisive normalization to maximize information coding in constrained neural circuits, and recent evidence suggests that analogous computations operate in decision-related brain areas. These adaptive computations implement a relative value code that may explain the characteristic context-dependent nature of behavioral violations of classical normative theory. Examining decision-making at the computational level thus provides a crucial link between the architecture of biological decision circuits and the form of empirical choice behavior. PMID:26722666

  8. Site-specific group selection drives locally adapted group compositions.

    PubMed

    Pruitt, Jonathan N; Goodnight, Charles J

    2014-10-16

    Group selection may be defined as selection caused by the differential extinction or proliferation of groups. The socially polymorphic spider Anelosimus studiosus exhibits a behavioural polymorphism in which females exhibit either a 'docile' or 'aggressive' behavioural phenotype. Natural colonies are composed of a mixture of related docile and aggressive individuals, and populations differ in colonies' characteristic docile:aggressive ratios. Using experimentally constructed colonies of known composition, here we demonstrate that population-level divergence in docile:aggressive ratios is driven by site-specific selection at the group level--certain ratios yield high survivorship at some sites but not others. Our data also indicate that colonies responded to the risk of extinction: perturbed colonies tended to adjust their composition over two generations to match the ratio characteristic of their native site, thus promoting their long-term survival in their natal habitat. However, colonies of displaced individuals continued to shift their compositions towards mixtures that would have promoted their survival had they remained at their home sites, regardless of their contemporary environment. Thus, the regulatory mechanisms that colonies use to adjust their composition appear to be locally adapted. Our data provide experimental evidence of group selection driving collective traits in wild populations.

  9. Adaptive Behavior of Primary School Students with Visual Impairments: The Impact of Educational Settings

    ERIC Educational Resources Information Center

    Metsiou, Katerina; Papadopoulos, Konstantinos; Agaliotis, Ioannis

    2011-01-01

    This study explored the adaptive behavior of primary school students with visual impairments, as well as the impact of educational setting on their adaptive behavior. Instrumentation included an informal questionnaire and the Vineland Adaptive Behavior Scales. Participants were 36 primary school students with visual impairments. The educational…

  10. Vineland Adaptive Behavior Profiles in Children with Autism and Moderate to Severe Developmental Delay.

    ERIC Educational Resources Information Center

    Fenton, Gemma; D'Ardia, Caterina; Valente, Donatella; Vecchio, Ilaria del; Fabrizi, Anna; Bernabei, Paola

    2003-01-01

    A study examined adaptive behavior profiles in children (ages 21-108 months) with moderate to severe developmental delay and autism (n=23) and without autism (n=27). The Vineland Adaptive Behavior Scales was administered, and contrary to initial predictions, the sample presented fairly homogeneous adaptive behavior profiles. (Contains references.)…

  11. Adaptive and Maladaptive Behavior in Children with Smith-Magenis Syndrome

    ERIC Educational Resources Information Center

    Martin, Staci C.; Wolters, Pamela L.; Smith, Ann C. M.

    2006-01-01

    Children with Smith-Magenis Syndrome (SMS) exhibit deficits in adaptive behavior but systematic studies using objective measures are lacking. This descriptive study assessed adaptive functioning in 19 children with SMS using the Vineland Adaptive Behavior Scales (VABS). Maladaptive behavior was examined through parent questionnaires and the…

  12. Physiological, behavioral and biochemical adaptations of intertidal fishes to hypoxia.

    PubMed

    Richards, Jeffrey G

    2011-01-15

    Hypoxia survival in fish requires a well-coordinated response to either secure more O(2) from the hypoxic environment or to limit the metabolic consequences of an O(2) restriction at the mitochondria. Although there is a considerable amount of information available on the physiological, behavioral, biochemical and molecular responses of fish to hypoxia, very little research has attempted to determine the adaptive value of these responses. This article will review current attempts to use the phylogenetically corrected comparative method to define physiological and behavioral adaptations to hypoxia in intertidal fish and further identify putatively adaptive biochemical traits that should be investigated in the future. In a group of marine fishes known as sculpins, from the family Cottidae, variation in hypoxia tolerance, measured as a critical O(2) tension (P(crit)), is primarily explained by variation in mass-specific gill surface area, red blood cell hemoglobin-O(2) binding affinity, and to a lesser extent variation in routine O(2) consumption rate (M(O(2))). The most hypoxia-tolerant sculpins consistently show aquatic surface respiration (ASR) and aerial emergence behavior during hypoxia exposure, but no phylogenetically independent relationship has been found between the thresholds for initiating these behaviors and P(crit). At O(2) levels below P(crit), hypoxia survival requires a rapid reorganization of cellular metabolism to suppress ATP consumption to match the limited capacity for O(2)-independent ATP production. Thus, it is reasonable to speculate that the degree of metabolic rate suppression and the quantity of stored fermentable fuel is strongly selected for in hypoxia-tolerant fishes; however, these assertions have not been tested in a phylogenetic comparative model.

  13. Adaptive aeroelastic composite wings - Control and optimization issues

    NASA Technical Reports Server (NTRS)

    Weisshaar, Terrence A.; Ehlers, Steven M.

    1992-01-01

    High-performance aircraft are adaptive machines composed of internal structural skeletons to which are attached control surfaces operated by hydraulic muscles to allow them to maneuver. The flight crew, avionic sensors and systems function as the brain and nervous system to adapt the machine to changing flight conditions, such as take-off, cruise and landing. The development of new materials that can expand or contract on command or change stiffness on demand will blur the now distinct boundaries between the structure, actuators and the control system. This paper discusses the use of imbedded active piezoelectric materials to change the aeroelastic stiffness of a lifting surface to allow this surface to control the aircraft. Expressions are developed for the piezoelectric material effectiveness when these active materials are combined with advanced composite structural materials for a swept, high-aspect-ratio wing. The interaction between advanced composite material properties and piezoelectric electromechanical properties is examined. The importance of choosing the proper active control laws is also illustrated.

  14. Adaptive divergence in pigment composition promotes phytoplankton biodiversity.

    PubMed

    Stomp, Maayke; Huisman, Jef; De Jongh, Floris; Veraart, Annelies J; Gerla, Daan; Rijkeboer, Machteld; Ibelings, Bas W; Wollenzien, Ute I A; Stal, Lucas J

    2004-11-04

    The dazzling diversity of the phytoplankton has puzzled biologists for decades. The puzzle has been enlarged rather than solved by the progressive discovery of new phototrophic microorganisms in the oceans, including picocyanobacteria, pico-eukaryotes, and bacteriochlorophyll-based and rhodopsin-based phototrophic bacteria. Physiological and genomic studies suggest that natural selection promotes niche differentiation among these phototrophic microorganisms, particularly with respect to their photosynthetic characteristics. We have analysed competition for light between two closely related picocyanobacteria of the Synechococcus group that we isolated from the Baltic Sea. One of these two has a red colour because it contains the pigment phycoerythrin, whereas the other is blue-green because it contains high contents of the pigment phycocyanin. Here we report theory and competition experiments that reveal stable coexistence of the two picocyanobacteria, owing to partitioning of the light spectrum. Further competition experiments with a third marine cyanobacterium, capable of adapting its pigment composition, show that this species persists by investing in the pigment that absorbs the colour not used by its competitors. These results demonstrate the adaptive significance of divergence in pigment composition of phototrophic microorganisms, which allows an efficient utilization of light energy and favours species coexistence.

  15. Human Adaptive Behavior in Common Pool Resource Systems

    PubMed Central

    Brandt, Gunnar; Merico, Agostino; Vollan, Björn; Schlüter, Achim

    2012-01-01

    Overexploitation of common-pool resources, resulting from uncooperative harvest behavior, is a major problem in many social-ecological systems. Feedbacks between user behavior and resource productivity induce non-linear dynamics in the harvest and the resource stock that complicate the understanding and the prediction of the co-evolutionary system. With an adaptive model constrained by data from a behavioral economic experiment, we show that users’ expectations of future pay-offs vary as a result of the previous harvest experience, the time-horizon, and the ability to communicate. In our model, harvest behavior is a trait that adjusts to continuously changing potential returns according to a trade-off between the users’ current harvest and the discounted future productivity of the resource. Given a maximum discount factor, which quantifies the users’ perception of future pay-offs, the temporal dynamics of harvest behavior and ecological resource can be predicted. Our results reveal a non-linear relation between the previous harvest and current discount rates, which is most sensitive around a reference harvest level. While higher than expected returns resulting from cooperative harvesting in the past increase the importance of future resource productivity and foster sustainability, harvests below the reference level lead to a downward spiral of increasing overexploitation and disappointing returns. PMID:23285180

  16. Adaptive behavior among adults with intellectual disabilities and its relationship to community independence.

    PubMed

    Woolf, Steve; Woolf, Christine Merman; Oakland, Thomas

    2010-06-01

    This study examined relationships between general adaptive behavior and the degree of community independence displayed by 272 adults with intellectual disabilities. Specifically, the Adaptive Behavior Assessment System--Second Edition (ABAS-II; Harrison & Oakland, 2003 ) was completed for each participant and compared with actual levels of work and residential independence. The participants' adaptive behavior accounted for 40%-43% of the variance in their work and residence independence. The results from this field-based study indicated that participants who displayed higher levels of adaptive behavior generally worked and lived more independently. Participants with the lowest general adaptive behavior required the highest degree of community supports. Implications of these findings are discussed.

  17. Longitudinal Examination of Adaptive Behavior in Autism Spectrum Disorders: Influence of Executive Function.

    PubMed

    Pugliese, Cara E; Anthony, Laura Gutermuth; Strang, John F; Dudley, Katerina; Wallace, Gregory L; Naiman, Daniel Q; Kenworthy, Lauren

    2016-02-01

    This study characterizes longitudinal change in adaptive behavior in 64 children and adolescents with autism spectrum disorder (ASD) without intellectual disability evaluated on multiple occasions, and examines whether prior estimate of executive function (EF) problems predicts future adaptive behavior scores. Compared to standardized estimates for their developmental stage, adaptive behavior in most participants was impaired and did not improve over time. Prior EF predicted later adaptive behavior in daily living skills and socialization domains after controlling for age and IQ. Self-monitoring behaviors robustly predicted later adaptive behavior in all domains (d = 0.60-0.94). Results support targeting treatment of adaptive skills in ASD, as well as the importance of assessing for EF problems that may contribute to adaptive behavior difficulties.

  18. Behavior of an adaptive bio-inspired spider web

    NASA Astrophysics Data System (ADS)

    Zheng, Lingyue; Behrooz, Majid; Huie, Andrew; Hartman, Alex; Gordaninejad, Faramarz

    2015-03-01

    The goal of this study is to demonstrate the feasibility of an artificial adaptive spider web with comparable behavior to a real spider web. First, the natural frequency and energy absorption ability of a passive web is studied. Next, a control system that consists of stepper motors, load cells and an Arduino, is constructed to mimic a spider's ability to control the tension of radial strings in the web. The energy related characteristics in the artificial spider web is examined while the pre-tension of the radial strings are varied. Various mechanical properties of a damaged spider web are adjusted to study their effect on the behavior of the web. It is demonstrated that the pre-tension and stiffness of the web's radial strings can significantly affect the natural frequency and the total energy of the full and damaged webs.

  19. Unified approach for predicting mechanical behaviors of textile composites

    SciTech Connect

    Hamada, H.; Fujita, A.; Maekawa, Z.; Yokoyama, A.

    1994-12-31

    The purpose of this study was to establish unified prediction method of mechanical properties and fracture behaviors in the composites reinforced with textile fabric preforms such as two and three-dimensional woven fabrics, braided fabrics and knitted fabrics. In this analysis model, factors deciding weaving structure such as fiber orientation state, crimp and continuity of fiber, transmission of force at cross part between fiber bundles and surface resin of the composite which affect on the mechanical properties and fracture behavior of the textile composites, were considered. The validity of this numerical analysis method was examined by comparing predicted results with experimental data. Consequently, it could be confirmed that this numerical analysis method was valid for predicting the mechanical properties and fracture behavior of the textile composites. In this analysis model, not only the mechanical properties but also local stress state and fracture behavior of the textile composites could be estimated.

  20. State Space Composition Technique for Intelligent Wheel Chair Adapting to Environment.

    NASA Astrophysics Data System (ADS)

    Hamagami, Tomoki; Hirata, Hironori

    This paper describes a state space composition technique for the adaptation to environment in the autonomous behavior of intelligent wheel chair (IWC).In the product like IWC with actual sensors, composing state space is difficult problem since environmental information can not be observed sufficiently from restricted sensor inputs.A lot of states observed from same environment position raise the fail of the learning and adaptation with active learning approach.In order to compensate for the effects of the sensor configuration, that is sensor position, angle and precision, a normalization processing of position detector is introduced.In sensor normalization process, IWC scans present environment via range sensors with executing spot-turn, and prepare scan-patterns of each sensor.Then the normalization process adjusts the phase and dynamic range of each pattern to the reference sensor scan-pattern, analyzing phase differences and scale factors of each pattern against reference pattern.Using phase difference and scale factors, automated state space composition is possible.From the simulation experiment with both artificial and real-worlddraft, the automated state space construction is confirmed as a practical approach for pre-processing for environment learning and adaptation.

  1. Effect of the curing method and composite volume on marginal and internal adaptation of composite restoratives.

    PubMed

    Souza-Junior, Eduardo José; de Souza-Régis, Marcos Ribeiro; Alonso, Roberta Caroline Bruschi; de Freitas, Anderson Pinheiro; Sinhoreti, Mario Alexandre Coelho; Cunha, Leonardo Gonçalves

    2011-01-01

    The aim of the present study was to evaluate the influence of curing methods and composite volumes on the marginal and internal adaptation of composite restoratives. Two cavities with different volumes (Lower volume: 12.6 mm(3); Higher volume: 24.5 mm(3)) were prepared on the buccal surface of 60 bovine teeth and restored using Filtek Z250 in bulk filling. For each cavity, specimens were randomly assigned into three groups according to the curing method (n=10): 1) continuous light (CL: 27 seconds at 600 mW/cm(2)); 2) soft-start (SS: 10 seconds at 150 mW/cm(2)+24 seconds at 600 mW/cm(2)); and 3) pulse delay (PD: five seconds at 150 mW/cm(2)+three minutes with no light+25 seconds at 600 mW/cm(2)). The radiant exposure for all groups was 16 J/cm(2). Marginal adaptation was measured with the dye staining gap procedure, using Caries Detector. Outer margins were stained for five seconds and the gap percentage was determined using digital images on a computer measurement program (Image Tool). Then, specimens were sectioned in slices and stained for five seconds, and the internal gaps were measured using the same method. Data were submitted to two-way analysis of variance and Tukey test (p<0.05). Composite volume had a significant influence on superficial and internal gap formation, depending on the curing method. For CL groups, restorations with higher volume showed higher marginal gap incidence than did the lower volume restorations. Additionally, the effect of the curing method depended on the volume. Regarding marginal adaptation, SS resulted in a significant reduction of gap formation, when compared to CL, for higher volume restorations. For lower volume restorations, there was no difference among the curing methods. For internal adaptation, the modulated curing methods SS and PD promoted a significant reduction of gap formation, when compared to CL, only for the lower volume restoration. Therefore, in similar conditions of the cavity configuration, the higher the

  2. Telescoping Mechanics: A New Paradigm for Composite Behavior Simulation

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Murthy, P. L. N.; Gotsis, P. K.; Mital. S. K.

    2004-01-01

    This report reviews the application of telescoping mechanics to composites using recursive laminate theory. The elemental scale is the fiber-matrix slice, the behavior of which propagates to laminate. The results from using applications for typical, hybrid, and smart composites and composite-enhanced reinforced concrete structures illustrate the versatility and generality of telescoping scale mechanics. Comparisons with approximate, single-cell, and two- and three-dimensional finite-element methods demonstrate the accuracy and computational effectiveness of telescoping scale mechanics for predicting complex composite behavior.

  3. Personality traits, future time perspective and adaptive behavior in adolescence.

    PubMed

    Gomes Carvalho, Renato Gil; Novo, Rosa Ferreira

    2015-04-24

    Several studies provide evidence of the importance of future time perspective (FTP) for individual success. However, little research addresses the relationship between FTP and personality traits, particularly if FTP can mediate their influence on behavior. In this study we analyze the mediating of FTP in the influence of personality traits on the way adolescents live their life at school. Sample consisted in 351 students, aged from 14 to 18 years-old, at different schooling levels. Instruments were the Portuguese version of the MMPI-A, particularly the PSY-5 dimensions (Aggressiveness, Psychoticism, Disconstraint, Neuroticism, Introversion), a FTP questionnaire, and a survey on school life, involving several indicators of achievement, social integration, and overall satisfaction. With the exception of Neuroticism, the results show significant mediation effects (p < .001) of FTP on most relationships between PSY-5 dimensions and school life variables. Concerning Disconstraint, FTP mediated its influence on overall satisfaction (β = -.125) and school achievement (β = -.106). In the case of Introversion, significant mediation effects occurred for interpersonal difficulties (β = .099) and participation in extracurricular activities (β = -.085). FTP was also a mediator of Psychoticism influence in overall satisfaction (β = -.094), interpersonal difficulties (β = .057), and behavior problems (β = .037). Finally, FTP mediated the influence of Aggressiveness on overall satisfaction (β = -.061), interpersonal difficulties (β = .040), achievement (β = -.052), and behavior problems (β = .023). Results are discussed considering the importance of FTP in the impact of some personality structural characteristics in students' school adaptation.

  4. Memory and adaptive behavior in population dynamics: anti-predator behavior as a case study.

    PubMed

    Pimenov, Alexander; Kelly, Thomas C; Korobeinikov, Andrei; O'Callaghan, Michael J; Rachinskii, Dmitrii

    2016-10-04

    Memory allows organisms to forecast the future on the basis of experience, and thus, in some form, is important for the development of flexible adaptive behavior by animal communities. To model memory, we use the concept of hysteresis, which mathematically is described by the Preisach operator. As a case study, we consider anti-predator adaptation in the classic Lotka-Volterra predator-prey model. Despite its simplicity, the model allows us to naturally incorporate essential features of an adaptive system and memory. Our analysis and simulations show that a system with memory can have a continuum of equilibrium states with non-trivial stability properties. The main factor that determines the actual equilibrium state to which a trajectory converges is the maximal number achieved by the population of predator along this trajectory.

  5. Low Temperature Adaptation Is Not the Opposite Process of High Temperature Adaptation in Terms of Changes in Amino Acid Composition

    PubMed Central

    Yang, Ling-Ling; Tang, Shu-Kun; Huang, Ying; Zhi, Xiao-Yang

    2015-01-01

    Previous studies focused on psychrophilic adaptation generally have demonstrated that multiple mechanisms work together to increase protein flexibility and activity, as well as to decrease the thermostability of proteins. However, the relationship between high and low temperature adaptations remains unclear. To investigate this issue, we collected the available predicted whole proteome sequences of species with different optimal growth temperatures, and analyzed amino acid variations and substitutional asymmetry in pairs of homologous proteins from related species. We found that changes in amino acid composition associated with low temperature adaptation did not exhibit a coherent opposite trend when compared with changes in amino acid composition associated with high temperature adaptation. This result indicates that during their evolutionary histories the proteome-scale evolutionary patterns associated with prokaryotes exposed to low temperature environments were distinct from the proteome-scale evolutionary patterns associated with prokaryotes exposed to high temperature environments in terms of changes in amino acid composition of the proteins. PMID:26614525

  6. Thermal expansion behavior of LDEF metal matrix composites

    NASA Technical Reports Server (NTRS)

    Le, Tuyen D.; Steckel, Gary L.

    1993-01-01

    The thermal expansion behavior of Long Duration Exposure Facility (LDEF) metal matrix composite materials was studied by (1) analyzing the flight data that was recorded on orbit to determine the effects of orbital time and heating/cooling rates on the performance of the composite materials, and (2) characterizing and comparing the thermal expansion behavior of post-flight LDEF and lab-control samples. The flight data revealed that structures in space are subjected to nonuniform temperature distributions, and thermal conductivity of a material is an important factor in establishing a uniform temperature distribution and avoiding thermal distortion. The flight and laboratory data showed that both Gr/Al and Gr/Mg composites were stabilized after prolonged thermal cycling on orbit. However, Gr/Al composites showed more stable thermal expansion behavior than Gr/Mg composites and offer advantages for space structures particularly where very tight thermal stability requirements in addition to high material performance must be met.

  7. Engine environmental effects on composite behavior

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Smith, G. T.

    1980-01-01

    A series of programs were conducted to investigate and develop the application of composite materials to turbojet engines. A significant part of that effort was directed to establishing the impact resistance and defect growth chracteristics of composite materials over the wide range of environmental conditions found in commercial turbojet engine operations. Both analytical and empirical efforts were involved. The experimental programs and the analytical methodology development as well as an evaluation program for the use of composite materials as fan exit guide vanes are summarized.

  8. Learning about stress: neural, endocrine and behavioral adaptations.

    PubMed

    McCarty, Richard

    2016-09-01

    In this review, nonassociative learning is advanced as an organizing principle to draw together findings from both sympathetic-adrenal medullary and hypothalamic-pituitary-adrenocortical (HPA) axis responses to chronic intermittent exposure to a variety of stressors. Studies of habituation, facilitation and sensitization of stress effector systems are reviewed and linked to an animal's prior experience with a given stressor, the intensity of the stressor and the appraisal by the animal of its ability to mobilize physiological systems to adapt to the stressor. Brain pathways that regulate physiological and behavioral responses to stress are discussed, especially in light of their regulation of nonassociative processes in chronic intermittent stress. These findings may have special relevance to various psychiatric diseases, including depression and post-traumatic stress disorder (PTSD).

  9. Light intensity adaptation and phycobilisome composition of Microcystis aeruginosa

    SciTech Connect

    Raps, S.; Kycia, J.H.; Ledbetter, M.C.; Siegelman, H.W.

    1985-12-01

    Phycobilisomes isolated from Microcystis aeruginosa grown to midlog at high light (270 microeinsteins per square meter per second) or at low light intensities (40 microeinsteins per square meter per second) were found to be identical. Electron micrographs established that they have a triangular central core apparently consisting of three allophycocyanin trimers surrounded by six rods, each composed of two hexameric phycocyanin molecules. The apparent mass of a phycobilisome obtained by gel filtration is 2.96 x 10/sup 6/ daltons. The molar ratio of the phycobiliproteins per phycobilisome is 12 phycocyanin hexamers:9 allophycocyanin trimers. The electron microscopic observations combined with the phycobilisome apparent mass and the phycobiliprotein stoichiometry data indicate that M. aeruginosa phycobilisomes are composed of a triangular central core of three stacks of three allophycocyanin trimers and six rods each containing two phycocyanin hexamers. Adaptation of M. aeruginosa to high light intensity results in a decrease in the number of phycobilisomes per cell with no alteration in phycobilisome composition or structure.

  10. Sequential composition of dynamically dexterous robot behaviors

    SciTech Connect

    Burridge, R.R.; Rizzi, A.A.; Koditschek, D.E.

    1999-06-01

    The authors report on efforts to develop a sequential robot controller-composition technique in the context of dexterous batting maneuvers. A robot with a flat paddle is required to strike repeatedly at a thrown ball until the ball is brought to rest on the paddle at a specified location. The robot`s reachable workspace is blocked by an obstacle that disconnects the free space formed when the ball and paddle remain in contact, forcing the machine to let go for a time to bring the ball to the desired state. The controller compositions the authors create guarantee that a ball introduced in the safe workspace remains there and is ultimately brought to the goal. They report on experimental results from an implementation of these formal composition methods, and present descriptive statistics characterizing the experiments.

  11. Tensile and fatigue behavior of tungsten/copper composites

    NASA Technical Reports Server (NTRS)

    Verrilli, Michael J.; Gabb, Timothy P.; Kim, Y. S.

    1989-01-01

    Work on W/Cu unidirectional composites was initiated to study the behavior of this ductile-ductile composite system under thermomechanical fatigue and to examine the applicability of fatigue-life prediction methods for thermomechanical fatigue of this metal matrix composite. The first step was to characterize the tensile behavior of four ply, 10 vol. percent W/Cu plates at room and elevated temperatures. Fatigue tests were conducted in load control on 0 degree specimens at 260 C. The maximum cyclic stress was varied but the minimum cyclic stress was kept constant. All tests were performed in vacuum. The strain at failure increased with increasing maximum cyclic stress.

  12. Wear and Friction Behavior of Metal Impregnated Microporous Carbon Composites

    NASA Technical Reports Server (NTRS)

    Goller, Gultekin; Koty, D. P.; Tewari, S. N.; Singh, M.; Tekin, A.

    1996-01-01

    Metal-matrix composites have been prepared by pressure-infiltration casting of copper-base alloy melts into microporous carbon preforms. The carbon preforms contained varying proportions of amorphous carbon and graphite. Load dependence of the wear and friction behavior of the composite pins has been examined under ambient conditions against cast-iron plates, using a pin-on-plate reciprocating wear tester. The wear resistance of the composite is significantly improved, as compared with the base alloy. Contrary to the normally expected behavior, the addition of graphite to the amorphous carbon does not reduce the friction coefficient, especially at high loads. The wear and friction behavior of the composites is very sensitive to the size and distribution of the microstructural constituents.

  13. Wear and friction behavior of metal impregnated microporous carbon composites

    SciTech Connect

    Goller, G.; Koty, D.P.; Tewari, S.N.; Singh, M.; Tekin, A.

    1996-11-01

    Metal-matrix composites have been prepared by pressure-infiltration casting of copper-base alloy melts into microporous carbon preforms. The carbon preforms contained varying proportions of amorphous carbon and graphite. Load dependence of the wear and friction behavior of the composite pins has been examined under ambient conditions against cast-iron plates, using a pin-on-plate reciprocating wear tester. The wear resistance of the composite is significantly improved, as compared with the base alloy. Contrary to the normally expected behavior, the addition of graphite to the amorphous carbon does not reduce the friction coefficient, especially at high loads. The wear and friction behavior of the composites is very sensitive to the size and distribution of the microstructural constituents.

  14. Probabilistic Simulation of Multi-Scale Composite Behavior

    NASA Technical Reports Server (NTRS)

    Chamis, Christos C.

    2012-01-01

    A methodology is developed to computationally assess the non-deterministic composite response at all composite scales (from micro to structural) due to the uncertainties in the constituent (fiber and matrix) properties, in the fabrication process and in structural variables (primitive variables). The methodology is computationally efficient for simulating the probability distributions of composite behavior, such as material properties, laminate and structural responses. Bi-products of the methodology are probabilistic sensitivities of the composite primitive variables. The methodology has been implemented into the computer codes PICAN (Probabilistic Integrated Composite ANalyzer) and IPACS (Integrated Probabilistic Assessment of Composite Structures). The accuracy and efficiency of this methodology are demonstrated by simulating the uncertainties in composite typical laminates and comparing the results with the Monte Carlo simulation method. Available experimental data of composite laminate behavior at all scales fall within the scatters predicted by PICAN. Multi-scaling is extended to simulate probabilistic thermo-mechanical fatigue and to simulate the probabilistic design of a composite redome in order to illustrate its versatility. Results show that probabilistic fatigue can be simulated for different temperature amplitudes and for different cyclic stress magnitudes. Results also show that laminate configurations can be selected to increase the redome reliability by several orders of magnitude without increasing the laminate thickness--a unique feature of structural composites. The old reference denotes that nothing fundamental has been done since that time.

  15. Mechanical behavior of mullite-zirconia composites

    NASA Astrophysics Data System (ADS)

    Sahnoune, F.; Saheb, N.

    2010-06-01

    In this work, mechanical properties of mullite-zirconia composites synthesised through reaction sintering of Algerian kaolin, α-Al2O3, and ZrO2 were characterized. Phases present and their transformations were characterized using x-ray diffraction. Hardness H and fracture toughness KIC were measured by Vickers indentation using a Zwick microhardness tester. The flexural strength was measured through three point bending test using an Instron Universal Testing Machine. It was found that the increase of ZrO2 content (from 0 to 32wt.%) decreased the microhardness of the composites from 14 to 10.8 GPa. However, the increase of ZrO2 content (from 0 to 24wt.%) increased the flexural strength of the composites from 142 to 390 MPa then decreased it with further increase of ZrO2 content. Also, the fracture toughness increased from 1.8 to 2.9 MPa.m1/2 with the increase of ZrO2 content from 0 to 32 wt.%; and the rate of the increase decreased at higher fractions of ZrO2 content. The average linear coefficient of thermal expansion (within the range 50 to 1450°C) for samples containing 0 and 16 wt.% ZrO2 sintered at 1600°C for 2 hours was 4.7 x10-6 K-1 and 5.2 x 10-6 K-1 respectively.

  16. Metal matrix composite micromechanics: In-situ behavior influence on composite properties

    NASA Technical Reports Server (NTRS)

    Murthy, P. L. N.; Hopkins, D. A.; Chamis, C. C.

    1989-01-01

    Recent efforts in computational mechanics methods for simulating the nonlinear behavior of metal matrix composites have culminated in the implementation of the Metal Matrix Composite Analyzer (METCAN) computer code. In METCAN material nonlinearity is treated at the constituent (fiber, matrix, and interphase) level where the current material model describes a time-temperature-stress dependency of the constituent properties in a material behavior space. The composite properties are synthesized from the constituent instantaneous properties by virtue of composite micromechanics and macromechanics models. The behavior of metal matrix composites depends on fabrication process variables, in situ fiber and matrix properties, bonding between the fiber and matrix, and/or the properties of an interphase between the fiber and matrix. Specifically, the influence of in situ matrix strength and the interphase degradation on the unidirectional composite stress-strain behavior is examined. These types of studies provide insight into micromechanical behavior that may be helpful in resolving discrepancies between experimentally observed composite behavior and predicted response.

  17. Neuropsychological predictors of adaptive kitchen behavior in geriatric psychiatry inpatients.

    PubMed

    Benedict, R H; Goldstein, M Z; Dobraski, M; Tannenhaus, J

    1997-10-01

    This study examined the degree to which demographic variables, psychiatric diagnosis, depression rating, and neuropsychological test performance predict adaptive kitchen behavior in geriatric psychiatry patients and normal elderly volunteers. Amixed group of 27 participants including 8 normal volunteers and 19 geriatric psychiatry inpatients underwent psychiatric evaluation, neuropsychological testing, and a kitchen skills assessment conducted in a natural setting. Both depression and dementia were prevalent among patients. The kitchen skills assessment was abnormal in 69% of patients, compared to none of the normal volunteers. Estimated premorbid IQs, psychiatric diagnosis, and neuropsychological test scores significantly predicted the pass/fail status on the kitchen skills assessment, but there was no effect for age, education, gender, or depression. The discriminant function analysis classified 92% of cases, and the canonical correlation coefficient was .84. Of the neuropsychological tests employed in the study, two tests involving visuospatial processing and attention were retained in the discriminant function analysis. The results are consistent with previous studies that suggest that visuospatial tasks are more predictive of instrumental activities of daily living than are cognitive tasks emphasizing verbal and memory abilities. In addition, we conclude that neuropsychological test data are useful and valid for the purpose of guiding clinical judgments regarding activities of daily living in geriatric psychiatry patients.

  18. Adaptive Behavior among Adults with Intellectual Disabilities and Its Relationship to Community Independence

    ERIC Educational Resources Information Center

    Woolf, Steve; Woolf, Christine Merman; Oakland, Thomas

    2010-01-01

    This study examined relationships between general adaptive behavior and the degree of community independence displayed by 272 adults with intellectual disabilities. Specifically, the Adaptive Behavior Assessment System-Second Edition (ABAS-II; Harrison & Oakland, 2003) was completed for each participant and compared with actual levels of work and…

  19. Adaptive Skills, Behavior Problems, and Parenting Stress in Mothers of Boys with Fragile X Syndrome

    ERIC Educational Resources Information Center

    Sarimski, Klaus

    2010-01-01

    The relationship of temperament, atypical behaviors, and adaptive behavior of young boys with Fragile X syndrome on mothers' parenting stress was analyzed. Twenty-six boys with Fragile X syndrome (30-88 months of age) participated. The overall development of the participants was significantly delayed with a specific profile of adaptive behaviors…

  20. Variability in Adaptive Behavior in Autism: Evidence for the Importance of Family History

    ERIC Educational Resources Information Center

    Mazefsky, Carla A.; Williams, Diane L.; Minshew, Nancy J.

    2008-01-01

    Adaptive behavior in autism is highly variable and strongly related to prognosis. This study explored family history as a potential source of variability in adaptive behavior in autism. Participants included 77 individuals (mean age = 18) with average or better intellectual ability and autism. Parents completed the Family History Interview about…

  1. Exploring the Structure of Adaptive Behavior: Project Report Number 87-1.

    ERIC Educational Resources Information Center

    Bruininks, Robert H.; McGrew, Kevin

    This report presents results from three research studies that were designed to explore both the definition and the structure of the adaptive behavior construct. The first study investigated the structure of adaptive behavior as a function of age, developmental level, and type of handicap through an exploratory factor analysis of both the…

  2. Longitudinal Examination of Adaptive Behavior in Autism Spectrum Disorders: Influence of Executive Function

    ERIC Educational Resources Information Center

    Pugliese, Cara E.; Anthony, Laura Gutermuth; Strang, John F.; Dudley, Katerina; Wallace, Gregory L.; Naiman, Daniel Q.; Kenworthy, Lauren

    2016-01-01

    This study characterizes longitudinal change in adaptive behavior in 64 children and adolescents with autism spectrum disorder (ASD) without intellectual disability evaluated on multiple occasions, and examines whether prior estimate of executive function (EF) problems predicts future adaptive behavior scores. Compared to standardized estimates…

  3. Fiber shape effects on metal matrix composite behavior

    NASA Technical Reports Server (NTRS)

    Brown, H. C.; Lee, H.-J.

    1992-01-01

    The effects of different fiber shapes on the behavior of metal matrix composites is computationally simulated. A three-dimensional finite element model consisting of a group of nine unidirectional fibers in a three by three unit cell array of a SiC/Ti-15-3 metal matrix composite is used in the analysis. The model is employed to represent five fiber shapes that include a circle, an ellipse, a kidney, and two different cross shapes. The distribution of stresses and the composite material properties, such as moduli, coefficients of thermal expansion, and Poisson's ratios, are obtained from the finite element analysis using the various fiber shapes. Comparisons of these results are used to determine the sensitivity of the composite behavior to the different fiber shapes. In general, fiber dominated properties are not affected by fiber geometry and matrix dominated properties are only moderately affected.

  4. WEAR BEHAVIOR OF CARBON NANOTUBE/HIGH DENSITY POLYETHYLENE COMPOSITES

    PubMed Central

    Johnson, Brian B.; Novotny, John E.; Advani, Suresh G.

    2009-01-01

    Carbon Nanotube/High Density Polyethylene (CNT/HDPE) composites were manufactured and tested to determine their wear behavior. The nanocomposites were made from untreated multi-walled carbon nanotubes and HDPE pellets. Thin films of the precursor materials were created with varying weight percentages of nanotubes (1%, 3%, and 5%), through a process of mixing and extruding. The precursor composites were then molded and machined to create test specimens for mechanical and wear tests. These included small punch testing to compare stiffness, maximum load and work-to-failure and block-on-ring testing to determine wear behavior. Each of the tests was conducted for the different weight percentages of composite as well as pure HDPE as the baseline. The measured mechanical properties and wear resistance of the composite materials increased with increasing nanotube content in the range studied. PMID:20161101

  5. DO CHILDREN WITH FRAGILE X SYNDROME SHOW DECLINES OR PLATEAUS IN ADAPTIVE BEHAVIOR?

    PubMed Central

    Hahn, Laura J.; Brady, Nancy C.; Warren, Steven F.; Fleming, Kandace K.

    2014-01-01

    This study explores if children with fragile X syndrome (FXS) show advances, declines, or plateaus in adaptive behavior over time and the relationship of nonverbal cognitive abilities and autistic behavior on these trajectories. Parents of 55 children with FXS completed the Vineland Adaptive Behavior Scales between 3 and 6 times from 2 to 10 years of age. Using raw scores, results indicate that about half of the sample showed advances in adaptive behavior, while the other half showed declines, indicating a regression in skills. Children who were more cognitively advanced and had less autistic behaviors had higher trajectories. Understanding the developmental course of adaptive behavior in FXS has implications for educational planning and intervention, especially for those children showing declines. PMID:26322389

  6. Behavior of Plastic Bonded Composite Explosives During High Acceleration

    NASA Astrophysics Data System (ADS)

    Lanzerotti, Y.

    1998-03-01

    The mechanical behavior of plastic bonded composite explosives has been studied during high acceleration in an ultracentrifuge. The pressed explosives studied include LX-14 [95% HMX (cyclotetramethylene- tetranitramine), 5% Estane], Composition A3 type II [91% RDX (cyclotrimethylene-trinitramine), 99% BDNPF (bis-dinitropropyl acetal formal), 6% CAB (cellulose acetate butyrate)], and PAX-3 (85% HMX, 9% BDNPF, 6% CAB/25% Aluminum). The fracture strength of LX-14 is greater than all pressed explosives studied to date. The fracture strength of Composition A3 type II is smaller than all pressed explosives studied to date.

  7. Tensile and compressive behavior of a swirl mat composite

    SciTech Connect

    Ruggles, M.B.

    1998-07-01

    The Durability of Lightweight Composite Structures Project was established at Oak Ridge National Laboratory (ORNL) by the US Department of Energy to provide the experimentally-based, durability-driven design guidelines necessary to assure long-term structural integrity of automotive composite components. The initial focus of the ORNL Durability Project was on one representative reference material--an isocyanurate (polyurethane) reinforced with continuous strand, swirl-mat E-glass. The present report describes tensile and compressive testing and results for the reference composite. Behavior trends and proportional limit are established for both tension and compression. Damage development due to tensile loading and strain rate effects are discussed.

  8. A Review: Development of a Microdose Model for Analysis of Adaptive Response and Bystander Dose Response Behavior

    PubMed Central

    Leonard, Bobby E.

    2008-01-01

    Prior work has provided incremental phases to a microdosimetry modeling program to describe the dose response behavior of the radio-protective adaptive response effect. We have here consolidated these prior works (Leonard 2000, 2005, 2007a, 2007b, 2007c) to provide a composite, comprehensive Microdose Model that is also herein modified to include the bystander effect. The nomenclature for the model is also standardized for the benefit of the experimental cellular radio-biologist. It extends the prior work to explicitly encompass separately the analysis of experimental data that is 1.) only dose dependent and reflecting only adaptive response radio-protection, 2.) both dose and dose-rate dependent data and reflecting only adaptive response radio-protection for spontaneous and challenge dose damage, 3.) only dose dependent data and reflecting both bystander deleterious damage and adaptive response radio-protection (AR-BE model). The Appendix cites the various applications of the model. Here we have used the Microdose Model to analyze the, much more human risk significant, Elmore et al (2006) data for the dose and dose rate influence on the adaptive response radio-protective behavior of HeLa x Skin cells for naturally occurring, spontaneous chromosome damage from a Brachytherapy type 125I photon radiation source. We have also applied the AR-BE Microdose Model to the Chromosome inversion data of Hooker et al (2004) reflecting both low LET bystander and adaptive response effects. The micro-beam facility data of Miller et al (1999), Nagasawa and Little (1999) and Zhou et al (2003) is also examined. For the Zhou et al (2003) data, we use the AR-BE model to estimate the threshold for adaptive response reduction of the bystander effect. The mammogram and diagnostic X-ray induction of AR and protective BE are observed. We show that bystander damage is reduced in the similar manner as spontaneous and challenge dose damage as shown by the Azzam et al (1996) data. We cite

  9. Engaging African American Fathers in Behavioral Parent Training: To Adapt or Not Adapt

    PubMed Central

    Kohl, Patricia L.; Seay, Kristen D.

    2015-01-01

    The Positive Parenting Program, Triple P, is an evidence-based parenting program with strong empirical support that increases parenting skills and decreases child behavior problems. Few studies on Triple P include fathers or African American fathers. This study was undertaken to determine if adaptation to Triple P level 4 is necessary to ensure fit with urban African American fathers. Qualitative focus groups and interviews were conducted with African American fathers. Some received a brief overview of the program before giving feedback (series A) and others received the entire intervention (series B). Inductive thematic analysis was used to analyze transcripts and codebooks were developed through an iterative process. Series B fathers had fewer negative perceptions and a more detailed perspective. Limited exposure to an intervention may cause participants to provide inaccurate data on intervention acceptability. The fathers’ initial perceptions of interventions, regardless of accuracy, will affect recruitment and engagement and must be addressed. One strategy is to tailor program examples and language to reflect the experiences of African American fathers. PMID:26190952

  10. Fracture behavior of hybrid composite laminates

    NASA Technical Reports Server (NTRS)

    Kennedy, J. M.

    1983-01-01

    The tensile fracture behavior of 15 center-notched hybrid laminates was studied. Three basic laminate groups were tested: (1) a baseline group with graphite/epoxy plies, (2) a group with the same stacking sequence but where the zero-deg plies were one or two plies of S-glass or Kevlar, and (3) a group with graphite plies but where the zero-deg plies were sandwiched between layers of perforated Mylar. Specimens were loaded linearly with time; load, far field strain, and crack opening displacement (COD) were monitored. The loading was stopped periodically and the notched region was radiographed to reveal the extent and type of damage (failure progression). Results of the tests showed that the hybrid laminates had higher fracture toughnesses than comparable all-graphite laminates. The higher fracture toughness was due primarily to the larger damage region at the ends of the slit; delamination and splitting lowered the stress concentration in the primary load-carrying plies. A linear elastic fracture analysis, which ignored delamination and splitting, underestimated the fracture toughness. For almost all of the laminates, the tests showed that the fracture toughness increased with crack length. The size of the damage region at the ends of the slit and COD measurements also increased with crack length.

  11. Friction and wear behavior of aluminum and composite airplane skins

    NASA Technical Reports Server (NTRS)

    Jackson, K. E.

    1984-01-01

    Friction and wear behavior was determined for small skin specimens under abrasive loading conditions typical of those occurring on the underside of a transport airplane during emergency belly landing. A test apparatus consisting of a standard belt sander provided the sliding surface. Small test specimens constructed of aluminum, standard graphite-epoxy composite, aramid-epoxy composite, and toughened-resin composites were tested undar a range of pressures, belt velocities, and belt-surface textures. The effects of these test variables on the wear rate and the coefficient of friction are discussed and comparisons are made between the composite materials and aluminum. The effect of fiber orientation in the composite materials on wear rate was also investigated. In addition, tests were performed in which thermocouples were imbedded into the various test specimens to obtain temperature-time histories during abrasion.

  12. High temperature behavior of polypropylene and polypropylene / glass composites

    NASA Astrophysics Data System (ADS)

    Shipley, Katherine Mary Herber

    Solid state die drawing of polymer matrix composite materials offers an opportunity to make products that cannot be produced by any other method. This is done by heating a composite billet to a temperature just below the melting point and drawing it through a heated converging die by pulling from the downstream side. Since this is done at high temperatures, it is imperative to understand the behavior of the polymer and the composites at high temperature. Therefore, in this work, the stress-strain behavior of neat polypropylene and polypropylene composites with glass flake and glass bead fillers was studied at 23°C, 130°C, and 145°C. The onset of debonding was found to occur at a lower stress and strain for the composites tested at higher temperature, while the loss of reinforcement was slower at the elevated temperatures. The interfacial interaction between the filler and matrix was also determined to be greater at elevated temperatures. The presence of filler particles also changed the character of the stress-strain curves at higher temperatures. Specifically, the filler induced a sharper neck region in the composites at elevated temperature. Annealing for one hour at temperatures between 130°C and 145°C produced a secondary, lower melting temperature peak in the DSC curves, which increased in prominence with increasing temperature. This increase in prominence was greater for the composites than for the neat polymer. Finally, the onset of debonding was studied using transverse strain vs. stress curves for the two composites. The debonding stress decreased with increasing temperature for both materials, and it was determined that stress amplification at the interface is greater for the flake composite than for the bead composite.

  13. Squeeze flow and compaction behavior of toughened polyimide matrix composites

    NASA Technical Reports Server (NTRS)

    Lee, Byung Lip; Pater, R.; Soucek, M. D.

    1991-01-01

    The main emphasis was placed upon the squeeze flow and compaction behavior of the Lewis Research Center (LaRC) research project series polyimide matrix composites. The measurement of squeeze film flow behavior was performed by a plastometer which monitors the change of thickness of a prepreg specimen laid between two parallel plates under the specified temperature and pressure history. A critical evaluation of the plastometer data was attempted by examining the morphology of the specimen at various points during the squeeze flow. The effects of crosslinks (Mc) of resin, imidization (B-ataging) condition, and pressure on the squeeze flow behavior were examined. Results are given.

  14. Design of smart composite platforms for adaptive trust vector control and adaptive laser telescope for satellite applications

    NASA Astrophysics Data System (ADS)

    Ghasemi-Nejhad, Mehrdad N.

    2013-04-01

    This paper presents design of smart composite platforms for adaptive trust vector control (TVC) and adaptive laser telescope for satellite applications. To eliminate disturbances, the proposed adaptive TVC and telescope systems will be mounted on two analogous smart composite platform with simultaneous precision positioning (pointing) and vibration suppression (stabilizing), SPPVS, with micro-radian pointing resolution, and then mounted on a satellite in two different locations. The adaptive TVC system provides SPPVS with large tip-tilt to potentially eliminate the gimbals systems. The smart composite telescope will be mounted on a smart composite platform with SPPVS and then mounted on a satellite. The laser communication is intended for the Geosynchronous orbit. The high degree of directionality increases the security of the laser communication signal (as opposed to a diffused RF signal), but also requires sophisticated subsystems for transmission and acquisition. The shorter wavelength of the optical spectrum increases the data transmission rates, but laser systems require large amounts of power, which increases the mass and complexity of the supporting systems. In addition, the laser communication on the Geosynchronous orbit requires an accurate platform with SPPVS capabilities. Therefore, this work also addresses the design of an active composite platform to be used to simultaneously point and stabilize an intersatellite laser communication telescope with micro-radian pointing resolution. The telescope is a Cassegrain receiver that employs two mirrors, one convex (primary) and the other concave (secondary). The distance, as well as the horizontal and axial alignment of the mirrors, must be precisely maintained or else the optical properties of the system will be severely degraded. The alignment will also have to be maintained during thruster firings, which will require vibration suppression capabilities of the system as well. The innovative platform has been

  15. Treating Individuals With Intellectual Disabilities and Challenging Behaviors With Adapted Dialectical Behavior Therapy

    PubMed Central

    Brown, Julie F.; Brown, Milton Z.; Dibiasio, Paige

    2013-01-01

    Approximately one third of adults with intellectual and developmental disabilities have emotion dysregulation and challenging behaviors (CBs). Although research has not yet confirmed that existing treatments adequately reduce CBs in this population, dialectical behavior therapy (DBT) holds promise, as it has been shown to effectively reduce CBs in other emotionally dysregulated populations. This longitudinal single-group pilot study examined whether individuals with impaired intellectual functioning would show reductions in CBs while receiving standard DBT individual therapy used in conjunction with the Skills System (DBT-SS), a DBT emotion regulation skills curriculum adapted for individuals with cognitive impairment. Forty adults with developmental disabilities (most of whom also had intellectual disabilities) and CBs, including histories of aggression, self-injury, sexual offending, or other CBs, participated in this study. Changes in their behaviors were monitored over 4 years while in DBT-SS. Large reductions in CBs were observed during the 4 years. These findings suggest that modified DBT holds promise for effectively treating individuals with intellectual and developmental disabilities. PMID:23914278

  16. High Temperature Mechanical Behavior of Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Hemann, John

    1996-01-01

    The research accomplishments under this grant were very extensive in the areas of the high temperature behavior of ceramics, ceramic composites and testing standards for these materials. Rather than try to summarize all this research I have enclosed research papers and reports which were completed with the funding provided by the grant.

  17. Effects of risperidone and parent training on adaptive functioning in children with pervasive developmental disorders and serious behavioral problems

    PubMed Central

    Scahill, Lawrence; McDougle, Christopher J.; Aman, Michael G.; Johnson, Cynthia; Handen, Benjamin; Bearss, Karen; Dziura, James; Butter, Eric; Swiezy, Naomi B.; Arnold, L. Eugene; Stigler, Kimberly A.; Sukhodolsky, Denis D.; Lecavalier, Luc; Pozdol, Stacie L.; Nikolov, Roumen; Ritz, Louise; Hollway, Jill A.; Korzekwa, Patrcia; Gavaletz, Allison; Kohn, Arlene E.; Koenig, Kathleen; Grinnon, Stacie; Mulick, James A.; Yu, Sunkyung; Vitiello, Benedetto

    2012-01-01

    Objective Children with Pervasive Developmental Disorders (PDDs) have deficits in social interaction, delayed communication and repetitive behavior as well as impairments in adaptive functioning. Many children actually show decline in adaptive skills compared to age mates over time. Method This 24-week, three-site, controlled clinical trial randomized 124 children (4 through 13 years of age) with PDDs and serious behavior problems to medication alone (MED; N=49; risperidone 0.5 to 3.5 mg/day (if ineffective, switch to aripiprazole was permitted) or medication plus parent training (PT) (COMB; N=75). Parents of children in COMB received an average of 11.4 PT sessions. Standard scores and Age Equivalent scores on Vineland Adaptive Behavior Scales were the outcome measures of primary interest. Results Seventeen subjects did not have a post-randomization Vineland. Thus, we used a mixed model with outcome conditioned on the baseline Vineland scores. Both groups showed improvement over the 24-week trial on all Vineland domains. Compared to MED, Vineland Socialization and Adaptive Composite Standard scores showed greater improvement in the COMB group (p = 0.01 and 0.05; effect sizes = 0.35.and 0.22, respectively). On Age Equivalent scores, Socialization and Communication domains showed greater improvement in COMB versus MED (p=0.03, 0.05; effect sizes = 0.33 and 0.14 respectively). Using logistic regression, children in the COMB group were twice as likely to make at least 6 months gain (equal to the passage of time) in the Vineland Communication Age Equivalent score compared to MED (p = 0.02). After controlling for IQ, this difference was no longer significant. Conclusion Reduction of serious maladaptive behavior promotes improvement in adaptive behavior. Medication plus PT shows modest additional benefit over medication alone. PMID:22265360

  18. Hybrid composites prepared from Industrial waste: Mechanical and swelling behavior

    PubMed Central

    Ahmed, Khalil

    2013-01-01

    In this assessment, hybrid composites were prepared from the combination of industrial waste, as marble waste powder (MWP) with conventional fillers, carbon black (CB) as well as silica as reinforcing material, incorporated with natural rubber (NR). The properties studied were curing, mechanical and swelling behavior. Assimilation of CB as well as silica into MWP containing NR compound responded in decreasing the scorch time and cure time besides increasing in the torque. Additionally, increasing the CB and silica in their respective NR hybrid composite increases the tensile, tear, modulus, hardness, and cross-link density, but decreases the elongation and swelling coefficient. The degradation property e.g., thermal aging of the hybrid composite was also estimated. The overall behavior at 70 °C aging temperature signified that the replacement of MS by CB and silica improved the aging performance. PMID:25750756

  19. Fiber shape effects on metal matrix composite behavior

    NASA Technical Reports Server (NTRS)

    Brown, H. C.; Lee, H.-J.; Chamis, C. C.

    1992-01-01

    The effects of different fiber shapes on the behavior of a SiC/Ti-15 metal matrix composite is computationally simulated. A three-dimensional finite element model consisting of a group of nine unidirectional fibers is used in the analysis. The model is employed to represent five different fiber shapes: a circle, an ellipse, a kidney, and two different cross shapes. The distribution of microstresses and the composite material properties, such as moduli, coefficients of thermal expansion, and Poisson's ratios, are obtained from the finite element analysis for the various fiber shapes. Comparisons of these results are used to determine the sensitivity of the composite behavior to the different fiber shapes and assess their potential benefits. No clear benefits result from different fiber shapes though there are some increases/decreases in isolated properties.

  20. The mechanical behavior of a hybrid metal matrix composite

    NASA Astrophysics Data System (ADS)

    Zok, F.; Jansson, S.; Evans, A. G.; Nardone, V.

    1991-09-01

    The mechanical behavior of a unidirectionally reinforced hybrid metal matrix composite in two different states has been studied: one with a “weakly bonded” interface and the other with a “strong” interface. Similarities and contrasts in mechanical behavior have been related to the properties of the interface. The longitudinal tensile strength and the crack growth initiation resistance are found to be insensitive to the condition of the interface. However, the material with the “weak” interface exhibits extensive debonding, resulting in a steeply increasing resistance curve and a large work of rupture. Furthermore, the weak interface reduces the transverse and torsional strength of the composite. This study illustrates how the tailoring of interfacial properties can improve the mechanical performance of composites for certain structural applications.

  1. Linking Screening for Emotional and Behavioral Problems to Problem-Solving Efforts: An Adaptive Model of Behavioral Assessment

    ERIC Educational Resources Information Center

    Volpe, Robert J.; Briesch, Amy M.; Chafouleas, Sandra M.

    2010-01-01

    This paper addresses several objectives of the special issue on universal screening by addressing gaps in the current research base concerning universal screening for mental, emotional, and behavioral health and by providing a framework for addressing the limitations of extant approaches. Specifically, an adaptive model of behavioral assessment…

  2. Brief Report: The Relationship between Language Skills, Adaptive Behavior, and Emotional and Behavior Problems in Pre-Schoolers with Autism

    ERIC Educational Resources Information Center

    Park, Carlie J.; Yelland, Gregory W.; Taffe, John R.; Gray, Kylie M.

    2012-01-01

    This study investigated the relationship between structural language skills, and communication skills, adaptive behavior, and emotional and behavior problems in pre-school children with autism. Participants were aged 3-5 years with autism (n = 27), and two comparison groups of children with developmental delay without autism (n = 12) and typically…

  3. On the Mechanical Behavior of Advanced Composite Material Structures

    NASA Astrophysics Data System (ADS)

    Vinson, Jack

    During the period between 1993 and 2004, the author, as well as some colleagues and graduate students, had the honor to be supported by the Office of Naval Research to conduct research in several aspects of the behavior of structures composed of composite materials. The topics involved in this research program were numerous, but all contributed to increasing the understanding of how various structures that are useful for marine applications behaved. More specifically, the research topics focused on the reaction of structures that were made of fiber reinforced polymer matrix composites when subjected to various loads and environmental conditions. This included the behavior of beam, plate/panel and shell structures. It involved studies that are applicable to fiberglass, graphite/carbon and Kevlar fibers imbedded in epoxy, polyester and other polymeric matrices. Unidirectional, cross-ply, angle ply, and woven composites were involved, both in laminated, monocoque as well as in sandwich constructions. Mid-plane symmetric as well as asymmetric laminates were studied, the latter involving bending-stretching coupling and other couplings that only can be achieved with advanced composite materials. The composite structures studied involved static loads, dynamic loading, shock loading as well as thermal and hygrothermal environments. One major consideration was determining the mechanical properties of composite materials subjected to high strain rates because the mechanical properties vary so significantly as the strain rate increases. A considerable number of references are cited for further reading and study for those interested.

  4. Fracture behavior of reinforced aluminum alloy matrix composites using thermal imaging tools

    NASA Astrophysics Data System (ADS)

    Avdelidis, N. P.; Exarchos, D.; Vazquez, P.; Ibarra-Castanedo, C.; Sfarra, S.; Maldague, X. P. V.; Matikas, T. E.

    2016-05-01

    In this work the influence of the microstructure at the vicinity of the interface on the fracture behavior of particulate-reinforced aluminum alloy matrix composites (Al/SiCp composites) is studied by using thermographic tools. In particular, infrared thermography was used to monitor the plane crack propagation behavior of the materials. The deformation of solid materials is almost always accompanied by heat release. When the material becomes deformed or is damaged and fractured, a part of the energy necessary to initiate and propagate the damage is transformed in an irreversible way into heat. The thermal camera detects the heat wave, generated by the thermo-mechanical coupling and the intrinsic dissipated energy during mechanical loading of the sample. By using an adapted detector, thermography records the two dimensional "temperature" field as it results from the infrared radiation emitted by the object. The principal advantage of infrared thermography is its noncontact, non-destructive character. This methodology is being applied to characterise the fracture behavior of the particulate composites. Infrared thermography is being used to monitor the plane crack propagation behavior of such materials. Furthermore, an innovative approach to use microscopic measurements using IR microscopic lenses was attempted, in order to enable smaller features (in the micro scale) to be imaged with accuracy and assurance.

  5. Adapting the Behavior Education Program for Preschool Settings

    ERIC Educational Resources Information Center

    Steed, Elizabeth A.

    2011-01-01

    Behavior Education Program (BEP) is the most researched targeted intervention that is used in schoolwide positive behavior intervention and supports (PBIS). It is a daily check-in and check-out system in which students receive extra attention for positive social behavior throughout their school day. This extra attention is intended to prevent…

  6. The Classroom Adaptation Scale: A Behavior Rating Scale Designed to Screen Primary Grade Children for School Adaptation Problems.

    ERIC Educational Resources Information Center

    Virbickis, Joseph A.

    After a brief historical review of the background and research, the paper focuses on development of a teacher-administered behavior rating scale to screen for school adaptation problems on a large scale basis using as Ss 15 primary grade teachers and their ratings of 315 primary grade children (ages 6-to-10 years) in their classes. A 16-item…

  7. Creep behavior of tungsten fiber reinforced niobium metal matrix composites

    NASA Technical Reports Server (NTRS)

    Grobstein, Toni L.

    1992-01-01

    Tungsten fiber reinforced niobium metal matrix composites were evaluated for use in space nuclear power conversion systems. The composite panels were fabricated using the arc-spray monotape technique at the NASA Lewis Research Center. The creep behavior of W/Nb composite material was determined at 1400 and 1500 K in vacuum over a wide range of applied loads. The time to reach 1 percent strain, the time to rupture, and the minimum creep rate were measured. The W/Nb composites exceeded the properties of monolithic niobium alloys significantly even when compared creep strength also was evaluated. Kirkendall void formation was observed at the fiber/matrix interface; the void distribution differed depending the fiber orientation relative to the stress axis. A relationship was found between the fiber orientation and the creep strength.

  8. Creep behavior of tungsten fiber reinforced niobium metal matrix composites

    NASA Technical Reports Server (NTRS)

    Grobstein, T. L.

    1989-01-01

    Tungsten fiber reinforced niobium metal matrix composites were evaluated for use in space nuclear power conversion systems. The composite panels were fabricated using the arc-spray monotape technique at the NASA Lewis Research Center. The creep behavior of W/Nb composite material was determined at 1400 and 1500 K in vacuum over a wide range of applied loads. The time to reach 1 percent strain, the time to rupture, and the minimum creep rate were measured. The W/Nb composites exceeded the properties of monolithic niobium alloys significantly even when compared on a strength to density basis. The effect of fiber orientation on the creep strength also was evaluated. Kirkendall void formation was observed at the fiber/matrix interface; the void distribution differed depending on the fiber orientation relative to the stress axis. A relationship was found between the fiber orientation and the creep strength.

  9. Pragmatics Driven Land Cover Service Composition Utilizing Behavior-Intention Model

    NASA Astrophysics Data System (ADS)

    Wu, Hao; Chen, Jun; Xing, Huaqiao; Li, Songnian; Hu, Juju

    2016-06-01

    Web service composition is one of the key issues to develop a global land cover (GLC) information service portal. Aiming at the defect that traditional syntax and semantic service compositionare difficult to take pragmatic information into account, the paper firstly analyses three tiers of web service language and their succession relations, discusses the conceptual model of pragmatic web service, and proposes the idea of pragmatics-oriented adaptive composition method based on the analysis of some examples. On this basis it puts forward the pragmatic web service model based on Behavior-Intention through presetting and expression of service usability, users' intention, and other pragmatic information, develops the on-demand assembly method based on the agent theory and matching and reconstruction method on heterogeneous message, solves the key technological issue of algorithm applicability and heterogeneous message transformation in the process of covering web service composition on the ground, applies these methods into service combination, puts forward the pragmatic driven service composition method based on behavior-intention model, and effectively settles the issue of coordination and interaction of composite service invocation.

  10. Behavioral ecology of captive species: using behavioral adaptations to assess and enhance welfare of nonhuman zoo animals.

    PubMed

    Koene, Paul

    2013-01-01

    This project aimed to estimate a species' adaptations in nature and in captivity, assess welfare, suggest environmental changes, and find species characteristics that underlie welfare problems in nonhuman animals in the zoo. First, the current status of zoo animal welfare assessment was reviewed, and the behavioral ecology approach was outlined. In this approach, databases of species characteristics were developed using (a) literature of natural behavior and (b) captive behavior. Species characteristics were grouped in 8 functional behavioral ecological fitness-related categories: space, time, metabolic, safety, reproductive, comfort, social, and information adaptations. Assessments of the strength of behavioral adaptations in relation to environmental demands were made based on the results available from the literature. The databases with literature at the species level were coupled with databases of (c) behavioral observations and (d) welfare assessments under captive conditions. Observation and welfare assessment methods were adapted from the animal on the farm realm and applied to zoo species. It was expected that the comparison of the repertoire of behaviors in natural and captive environments would highlight welfare problems, provide solutions to welfare problems by environmental changes, and identify species characteristics underlying zoo animal welfare problems.

  11. Composition and adaptation in the life of Robert Schumann.

    PubMed

    Graves, John S

    2005-01-01

    The composer Robert Schumann, who suffered from bipolar disorder, utilized his impressive musical and literary talents in attempts to adapt to multiple developmental traumas, separations, and losses as well as to the ongoing ravages of his mood disorder. By analyzing several of his Lieder, the author formulates and describes several defense mechanisms involved in these adaptations. These include identification with the lost object, the use of transitional objects and phenomena, sublimation, denial, minimization, idealization, playfulness, and the employment of healthy obsessive traits. Schumann utilized these adaptive defenses successfully for a brief period, thus coping with a difficult separation from his fiancée, Clara. Ultimately, however, he was unable to experience mature mourning regarding the deaths of several family members. The author, drawing on his extensive experience with treating bipolar individuals in outpatient settings, discusses some of the difficulties that many bipolar patients like Schumann have with mourning, including early developmental vulnerabilities to separation and loss, the disorganizing effects of bipolar mood episodes on cognition and self-coherence, the need to camouflage affects reminiscent of bipolar mood episodes, and experiencing these affects and mood episodes as traumatic reoccurrences. By studying the biographies of creative individuals such as Schumann, clinicians can expand their appreciation of their patients' adaptive capacities and thus assist them in restoring a sense of hope and vitality in their lives.

  12. Adapted Dialectical Behavior Therapy for Adolescents with Self-injurious Thoughts and Behaviors.

    PubMed

    Courtney, Darren B; Flament, Martine F

    2015-07-01

    The purpose of this study was to explore clinical changes observed in suicidal adolescents treated with an adapted form of Dialectical Behavior Therapy for adolescents (A-DBT-A) in a tertiary care setting. We conducted an open-label naturalistic study including 61 adolescents with self-injurious thoughts and behaviors and associated features of borderline personality disorder, who underwent a 15-week course of A-DBT-A. Pre- and post-treatment measures were administered, the primary outcome being the total score on the Suicidal Ideas Questionnaire. Self-harm, symptoms of borderline personality disorder, resiliency measures, predictors of response, and predictors of attrition were also explored. Among participants who completed post-treatment measures, we found a significant reduction in suicidal ideation (n = 31, p < 0.001). Secondary outcomes also suggested improvement. Baseline substance use predicted attrition (HR 2.51; 95% CI 1.03-6.14; p < 0.05), as did baseline impulsivity score on the Life Problems Inventory (HR 1.03; 95% CI 1.004-1.06; p < 0.05). Overall, we observed clinical improvements in adolescents receiving A-DBT-A.

  13. A Critical Analysis of the Behavioral Adaptation Explanation of the Probing Effect.

    ERIC Educational Resources Information Center

    Levine, Timothy R.; McCornack, Steven A.

    1996-01-01

    Documents three problems with the behavioral adaption explanation (BAE) that, taken together, suggest that it cannot account for the probing effect, i.e., the finding that sources interrogatively probed appear more honest to message recipients than nonprobed sources. (TB)

  14. Can Behavioral Adaptation Explain the Probing Effect? Rejoinder to Buller et al.

    ERIC Educational Resources Information Center

    Levine, Timothy R.; McCornack, Steven A.

    1996-01-01

    Responds to David Buller's defense of Behavioral Adaption Explanation (BAE), which was, in turn, written in response to the authors' critical analysis of BAE as an explanation for the probing effect. (TB)

  15. Adapting Autonomous Behavior Based on an Estimate of an Operator’s Trust

    DTIC Science & Technology

    2014-11-01

    teammate’s trust and adapt to it, and also pro- vide directions for this work. 2 Inverse Trust and Behavior Adaptation Traditional trust metrics measure how...looking at an inverse trust metric where an agent (the robot) estimates how much trust another agent has in it. One option would be to get direct feedback...trustworthy behaviors from previous adap- tations (Floyd, Drinkwater, and Aha 2014b). 3 Discussion Our work has focused on an approach for inverse trust

  16. Systematic Review of Engagement in Culturally Adapted Parent Training for Disruptive Behavior

    ERIC Educational Resources Information Center

    Butler, Ashley M.; Titus, Courtney

    2015-01-01

    This article reviews the literature reporting engagement (enrollment, attendance, and attrition) in culturally adapted parent training for disruptive behavior among racial/ethnic minority parents of children ages 2 to 7 years. The review describes the reported rates of engagement in adapted interventions and how engagement is analyzed in studies,…

  17. The Relation between Intellectual Functioning and Adaptive Behavior in the Diagnosis of Intellectual Disability

    ERIC Educational Resources Information Center

    Tassé, Marc J.; Luckasson, Ruth; Schalock, Robert L.

    2016-01-01

    Intellectual disability originates during the developmental period and is characterized by significant limitations both in intellectual functioning and in adaptive behavior as expressed in conceptual, social, and practical adaptive skills. In this article, we present a brief history of the diagnostic criteria of intellectual disability for both…

  18. A Pilot Study of Culturally Adapted Cognitive Behavior Therapy for Hispanics with Major Depression

    ERIC Educational Resources Information Center

    Interian, Alejandro; Allen, Lesley A.; Gara, Michael A.; Escobar, Javier I.

    2008-01-01

    The purpose of this study was to evaluate a culturally adapted cognitive-behavioral treatment (CBT) for major depression among Hispanics in primary care. Cultural adaptations were applied based on a range of cultural considerations described in the literature. Fifteen Hispanic primary care patients with major depression were enrolled. All…

  19. Adapted Behavior Therapy for Persistently Depressed Primary Care Patients: An Open Trial

    ERIC Educational Resources Information Center

    Uebelacker, Lisa A.; Weisberg, Risa B.; Haggarty, Ryan; Miller, Ivan W.

    2009-01-01

    Major depressive disorder is commonly treated in primary care settings. Psychotherapy occurring in primary care should take advantage of the unique aspects of the setting and must adapt to the problems and limitations of the setting. In this open trial, the authors used a treatment development model to adapt behavior therapy for primary care…

  20. Someone has to give in: theta oscillations correlate with adaptive behavior in social bargaining

    PubMed Central

    Zamorano, Francisco; López, Tamara; Rodriguez, Carlos; Cosmelli, Diego; Aboitiz, Francisco

    2014-01-01

    During social bargain, one has to both figure out the others’ intentions and behave strategically in such a way that the others’ behaviors will be consistent with one’s expectations. To understand the neurobiological mechanisms underlying these behaviors, we used electroencephalography while subjects played as proposers in a repeated ultimatum game. We found that subjects adapted their offers to obtain more acceptances in the last round and that this adaptation correlated negatively with prefrontal theta oscillations. People with higher prefrontal theta activity related to a rejection did not adapt their offers along the game to maximize their earning. Moreover, between-subject variation in posterior theta oscillations correlated positively with how individual theta activity influenced the change of offer after a rejection, reflecting a process of behavioral adaptation to the others’ demands. Interestingly, people adapted better their offers when they knew that they where playing against a computer, although the behavioral adaptation did not correlate with prefrontal theta oscillation. Behavioral changes between human and computer games correlated with prefrontal theta activity, suggesting that low adaptation in human games could be a strategy. Taken together, these results provide evidence for specific roles of prefrontal and posterior theta oscillations in social bargaining. PMID:24493841

  1. Someone has to give in: theta oscillations correlate with adaptive behavior in social bargaining.

    PubMed

    Billeke, Pablo; Zamorano, Francisco; López, Tamara; Rodriguez, Carlos; Cosmelli, Diego; Aboitiz, Francisco

    2014-12-01

    During social bargain, one has to both figure out the others' intentions and behave strategically in such a way that the others' behaviors will be consistent with one's expectations. To understand the neurobiological mechanisms underlying these behaviors, we used electroencephalography while subjects played as proposers in a repeated ultimatum game. We found that subjects adapted their offers to obtain more acceptances in the last round and that this adaptation correlated negatively with prefrontal theta oscillations. People with higher prefrontal theta activity related to a rejection did not adapt their offers along the game to maximize their earning. Moreover, between-subject variation in posterior theta oscillations correlated positively with how individual theta activity influenced the change of offer after a rejection, reflecting a process of behavioral adaptation to the others' demands. Interestingly, people adapted better their offers when they knew that they where playing against a computer, although the behavioral adaptation did not correlate with prefrontal theta oscillation. Behavioral changes between human and computer games correlated with prefrontal theta activity, suggesting that low adaptation in human games could be a strategy. Taken together, these results provide evidence for specific roles of prefrontal and posterior theta oscillations in social bargaining.

  2. Damping Behavior of Alumina Epoxy Nano-Composites

    NASA Astrophysics Data System (ADS)

    Katiyar, Priyanka; Kumar, Anand

    2016-10-01

    Polymer nano composites, consisting of a polymer matrix with nanoparticle filler, have been predicted to be one of the most beneficial applications of nanotechnology. Addition of nano particulates to a polymer matrix enhances its performance by capitalizing on the nature and properties of the nano-scale fillers. The damping behavior of composites with nano structured phases is significantly different from that of micro structured materials. Viscoelastic homopolymer exhibit a high material damping response over a relatively narrow range of temperature and frequencies. In many practical situations, a polymeric structure is required to possess better strength and stiffness properties together with a reasonable damping behavior. Viscoelastic polymers show higher loss factor beyond the glassy region which comes with a significant drop in the specific modulus. Addition of nano alumina particles to epoxy leads to improved strength and stiffness properties with an increase in glass transition temperature while retaining its damping capability. Experimental investigations are carried out on composite beam specimen fabricated with different compositions of alumina nano particles in epoxy to evaluate loss factor, tan δ. Impact damping method is used for time response analysis. A single point Laser is used to record the transverse displacement of a point on the composite beam specimen. The experimental results are compared with theoretical estimation of loss factor using Voigt estimation. The effect of inter phase is included in theoretical estimation of loss factor. The result reveals that the study of interface properties is very important in deriving the overall loss factor of the composite since interface occupies a significant volume fraction in the composite.

  3. Simulation of Fatigue Behavior of High Temperature Metal Matrix Composites

    NASA Technical Reports Server (NTRS)

    Tong, Mike T.; Singhal, Suren N.; Chamis, Christos C.; Murthy, Pappu L. N.

    1996-01-01

    A generalized relatively new approach is described for the computational simulation of fatigue behavior of high temperature metal matrix composites (HT-MMCs). This theory is embedded in a specialty-purpose computer code. The effectiveness of the computer code to predict the fatigue behavior of HT-MMCs is demonstrated by applying it to a silicon-fiber/titanium-matrix HT-MMC. Comparative results are shown for mechanical fatigue, thermal fatigue, thermomechanical (in-phase and out-of-phase) fatigue, as well as the effects of oxidizing environments on fatigue life. These results show that the new approach reproduces available experimental data remarkably well.

  4. The fatigue behavior of composite laminates under various mean stresses

    NASA Technical Reports Server (NTRS)

    Rotem, A.

    1991-01-01

    A method is developed for predicting the S-N curve of a composite laminate which is subjected to an arbitrary stress ratio, R (minimum stress/maximum stress). The method is based on the measuring of the S-N behavior of two distinct cases, tension-tension and compression-compression fatigue loadings. Using these parameters, expressions are formulated that estimate the fatigue behavior under any stress ratio loading. Experimental results from the testing of graphite/epoxy laminates, with various structures, are compared with the predictions and show good agreement.

  5. Comparison of Measures of Adaptive Behaviors in Preschool Children.

    ERIC Educational Resources Information Center

    Garrity, Linda I.; Servos, Andria B.

    1978-01-01

    Nonproblem and problem children were compared on Minnesota Child Development Inventory, Classroom Adjustment Rating Scale, Ottawa School Behavior Survey, AML Behavior Rating Scale, Teacher Rating Scale, and Denver Developmental Screening Test. Problem children scored significantly lower than nonproblem children on all measures. Minnesota Child…

  6. Effects of the emotion system on adaptive behavior.

    PubMed

    Giske, Jarl; Eliassen, Sigrunn; Fiksen, Øyvind; Jakobsen, Per J; Aksnes, Dag L; Jørgensen, Christian; Mangel, Marc

    2013-12-01

    A central simplifying assumption in evolutionary behavioral ecology has been that optimal behavior is unaffected by genetic or proximate constraints. Observations and experiments show otherwise, so that attention to decision architecture and mechanisms is needed. In psychology, the proximate constraints on decision making and the processes from perception to behavior are collectively described as the emotion system. We specify a model of the emotion system in fish that includes sensory input, neuronal computation, developmental modulation, and a global organismic state and restricts attention during decision making for behavioral outcomes. The model further includes food competition, safety in numbers, and a fluctuating environment. We find that emergent strategies in evolved populations include common emotional appraisal of sensory input related to fear and hunger and also include frequency-dependent rules for behavioral responses. Focused attention is at times more important than spatial behavior for growth and survival. Spatial segregation of the population is driven by personality differences. By coupling proximate and immediate influences on behavior with ultimate fitness consequences through the emotion system, this approach contributes to a unified perspective on the phenotype, by integrating effects of the environment, genetics, development, physiology, behavior, life history, and evolution.

  7. Corrosion behavior of a particulate metal-matrix composite

    SciTech Connect

    Bertolini, L.; Brunella, M.F.; Candiani, S.

    1999-04-01

    The corrosion behavior of a particulate-reinforced metal-matrix composite (MMC) with an Al 6061-T6 (UNS A96061, Al-Mg-Si) matrix and 10 vol% alumina (Al{sub 2}O{sub 3}) particles was studied. The material was tested in different extrusion and forging conditions. Potentiodynamic polarization tests were carried out in aerated and deaerated sodium chloride (NaCl) solutions with concentrations from 0.06 N up to saturation to study pitting corrosion initiation. Three-month immersion tests were performed in aerated solutions. Results showed pitting corrosion initiated in aerated solutions, even for the lower chloride concentration. No significant influence of Al{sub 2}O{sub 3} particles on corrosion susceptibility of the matrix was observed. However, corrosion attacks occurred preferentially in the vicinity of the reinforcing particles. Extrusion or forging treatment did not affect corrosion behavior of the composite material significantly.

  8. Corrosive wear behavior of 2014 and 6061 aluminum alloy composites

    NASA Astrophysics Data System (ADS)

    Varma, S. K.; Andrews, S.; Vasquez, G.

    1999-02-01

    Alloys of 2014 and 6061 aluminum reinforced with 0.1 volume fraction of alumina particles (VFAP) were subjected to impact scratching during a corrosive wear process. The transient currents generated due to the impact were measured in the two composites as well as in their respective monoliths. The effect of solutionizing time on the transient currents was correlated to the near surface microstructures, scratch morphology, concentration of quenched-in vacancies, and changes in grain sizes. It was observed that the transient current values increase with an increase in solutionizing time, indicating that the corrosive wear behavior is not strongly affected by the grain boundaries. However, a combination of pitting and the galvanic corrosion may account for the typical corrosive wear behavior exhibited by the alloys and the composites of this study.

  9. Effect of Composite Substrates on the Mechanical Behavior of Brazed Joints in Metal-Composite System

    NASA Technical Reports Server (NTRS)

    Singh, M.; Morscher, Gregory N.; Shpargel, Tarah; Asthana, Rajiv

    2006-01-01

    Advanced composite components are being considered for a wide variety of demanding applications in aerospace, space exploration, and ground based systems. A number of these applications require robust integration technologies to join dissimilar materials (metalcomposites) into complex structural components. In this study, three types of composites (C-C, C-SiC, and SiC-SiC) were vacuum brazed to commercially pure Ti using the active metal braze alloy Cusil-ABA (63Ag-35.3Cu-1.75Ti). Composite substrates with as fabricated and polished surfaces were used for brazing. The microstructure and composition of the joint, examined using scanning electron microscopy (SEM) coupled with energy dispersive spectroscopy (EDS), showed sound metallurgical bonding in all systems. The butt strap tensile (BST) test was performed on bonded specimens at room and elevated temperatures. Effect of substrate composition, interlaminar properties, and surface roughness on the mechanical properties and failure behavior of joints will be discussed.

  10. Static fracture behavior of multilayered alumina-zirconia composites

    NASA Astrophysics Data System (ADS)

    Moon, Robert John

    The techniques for evaluating the static fracture behavior of monolithic materials are well established. Applying these same techniques to evaluate the fracture behavior of multilayered and/or gradient composites requires consideration of the changing microstructural influence on fracture. In the current study, single-edge-V-notched-beam (SEVNB) testing was used to evaluate the R-curve behavior of multilayered gradient alumina-zirconia composites. Crack initiation and extension from the V-notch tip were observed via in situ optical microscopy. The V-notch tip was positioned near specific microstructural features within the composite and during loading short cracks (5 to 75 mum) were initiated from the V-notch tip and extended stably in ˜10 mum increments. The influence of gradient microstructures, layer-layer interfaces, platelike alumina additions, residual stresses, and the direction of crack propagation on the resulting R-curves were investigated. The fracture mechanics weight function was used to estimate the fracture behavior based on the stress distribution (applied bending stress and residual stresses). The results were compared to the measured R-curves and the weight function analysis was observed to underestimate the measured KR. These differences were likely due to bridging stresses within the samples that were not accounted for in the weight function analysis. Initial attempts to account for bridging stress within the weight function analysis were in good agreement with the measured R-curves for the monolithic sample and for the samples having a step-wise change in residual stress. However, the same bridging function was not applicable for the samples having a composition gradient within each layer.

  11. Thermal shock behavior of fiber-reinforced composites

    SciTech Connect

    Wang, H.; Singh, R.N.; Beecher, S.C.; Dinwiddie, R.B.

    1995-02-01

    The thermal shock behavior of three types of continuous fiber-reinforced ceramic composites (Nextel{trademark} or Nicalon{trademark} fiber-reinforced chemical vapor infiltrated or polymer-derived SiC matrix composites) was studied using the water quench technique. The thermal shock induced damage was characterized by both destructive and nondestructive techniques. As compared with monolithic ceramics, the continuous fiber-reinforced ceramic composites were capable of preventing catastrophic failure caused by thermal shock and were able to retain a significant portion of their original strength at {Delta}{Tau} = 1000{degrees}C. The nondestructive techniques involved measuring the thermal diffusivity by the flash technique and determining the Young`s modulus by the dynamic resonance method. It has been demonstrated that these nondestructive techniques can detect damage induced by thermal shock and are more sensitive in detecting damage in the early stage than the conventional destructive technique of measuring the retained strength.

  12. Kindergarten Children's Perceptions of "Anthropomorphic Artifacts" with Adaptive Behavior

    ERIC Educational Resources Information Center

    Kuperman, Asi; Mioduser, David

    2012-01-01

    In recent years, children from a kindergarten in central Israel have been exposed to learning experiences in technology as part of the implementation of a curriculum based on technological thinking, including topics related to behaving-adaptive-artifacts (e.g., robots). This study aims to unveil children's stance towards behaving artifacts:…

  13. Predicting Adaptive Behavior from the Bayley Scales of Infant Development.

    ERIC Educational Resources Information Center

    Hotard, Stephen; McWhirter, Richard

    To examine the proportion of variance in adaptive functioning predictable from mental ability, chronological age, I.Q., evidence of brain malfunction, seizure medication, and receptive and expressive language scores, 25 severely and profoundly retarded institutionalized persons (2-19 years old) were administered the Bayley Infant Scale Mental…

  14. Investigation of Buckling Behavior of Composite Shell Structures with Cutouts

    NASA Astrophysics Data System (ADS)

    Arbelo, Mariano A.; Herrmann, Annemarie; Castro, Saullo G. P.; Khakimova, Regina; Zimmermann, Rolf; Degenhardt, Richard

    2015-12-01

    Thin-walled cylindrical composite shell structures can be applied in space applications, looking for lighter and cheaper launcher transport system. These structures are prone to buckling under axial compression and may exhibit sensitivity to geometrical imperfections. Today the design of such structures is based on NASA guidelines from the 1960's using a conservative lower bound curve generated from a database of experimental results. In this guideline the structural behavior of composite materials may not be appropriately considered since the imperfection sensitivity and the buckling load of shells made of such materials depend on the lay-up design. It is clear that with the evolution of the composite materials and fabrication processes this guideline must be updated and / or new design guidelines investigated. This need becomes even more relevant when cutouts are introduced to the structure, which are commonly necessary to account for access points and to provide clearance and attachment points for hydraulic and electric systems. Therefore, it is necessary to understand how a cutout with different dimensions affects the buckling load of a thin-walled cylindrical shell structure in combination with other initial geometric imperfections. In this context, this paper present some observations regarding the buckling load behavior vs. cutout size and radius over thickness ratio, of laminated composite curved panels and cylindrical shells, that could be applied in further recommendations, to allow identifying when the buckling of the structure is dominated by the presence of the cutout or by other initial imperfections.

  15. Hierarchical adaptive nanostructured PVD coatings for extreme tribological applications: the quest for nonequilibrium states and emergent behavior.

    PubMed

    Fox-Rabinovich, German S; Yamamoto, Kenji; Beake, Ben D; Gershman, Iosif S; Kovalev, Anatoly I; Veldhuis, Stephen C; Aguirre, Myriam H; Dosbaeva, Goulnara; Endrino, Jose L

    2012-08-01

    Adaptive wear-resistant coatings produced by physical vapor deposition (PVD) are a relatively new generation of coatings which are attracting attention in the development of nanostructured materials for extreme tribological applications. An excellent example of such extreme operating conditions is high performance machining of hard-to-cut materials. The adaptive characteristics of such coatings develop fully during interaction with the severe environment. Modern adaptive coatings could be regarded as hierarchical surface-engineered nanostructural materials. They exhibit dynamic hierarchy on two major structural scales: (a) nanoscale surface layers of protective tribofilms generated during friction and (b) an underlying nano/microscaled layer. The tribofilms are responsible for some critical nanoscale effects that strongly impact the wear resistance of adaptive coatings. A new direction in nanomaterial research is discussed: compositional and microstructural optimization of the dynamically regenerating nanoscaled tribofilms on the surface of the adaptive coatings during friction. In this review we demonstrate the correlation between the microstructure, physical, chemical and micromechanical properties of hard coatings in their dynamic interaction (adaptation) with environment and the involvement of complex natural processes associated with self-organization during friction. Major physical, chemical and mechanical characteristics of the adaptive coating, which play a significant role in its operating properties, such as enhanced mass transfer, and the ability of the layer to provide dissipation and accumulation of frictional energy during operation are presented as well. Strategies for adaptive nanostructural coating design that enhance beneficial natural processes are outlined. The coatings exhibit emergent behavior during operation when their improved features work as a whole. In this way, as higher-ordered systems, they achieve multifunctionality and high wear

  16. Hierarchical adaptive nanostructured PVD coatings for extreme tribological applications: the quest for nonequilibrium states and emergent behavior

    PubMed Central

    Fox-Rabinovich, German S; Yamamoto, Kenji; Beake, Ben D; Gershman, Iosif S; Kovalev, Anatoly I; Veldhuis, Stephen C; Aguirre, Myriam H.; Dosbaeva, Goulnara; Endrino, Jose L

    2012-01-01

    Adaptive wear-resistant coatings produced by physical vapor deposition (PVD) are a relatively new generation of coatings which are attracting attention in the development of nanostructured materials for extreme tribological applications. An excellent example of such extreme operating conditions is high performance machining of hard-to-cut materials. The adaptive characteristics of such coatings develop fully during interaction with the severe environment. Modern adaptive coatings could be regarded as hierarchical surface-engineered nanostructural materials. They exhibit dynamic hierarchy on two major structural scales: (a) nanoscale surface layers of protective tribofilms generated during friction and (b) an underlying nano/microscaled layer. The tribofilms are responsible for some critical nanoscale effects that strongly impact the wear resistance of adaptive coatings. A new direction in nanomaterial research is discussed: compositional and microstructural optimization of the dynamically regenerating nanoscaled tribofilms on the surface of the adaptive coatings during friction. In this review we demonstrate the correlation between the microstructure, physical, chemical and micromechanical properties of hard coatings in their dynamic interaction (adaptation) with environment and the involvement of complex natural processes associated with self-organization during friction. Major physical, chemical and mechanical characteristics of the adaptive coating, which play a significant role in its operating properties, such as enhanced mass transfer, and the ability of the layer to provide dissipation and accumulation of frictional energy during operation are presented as well. Strategies for adaptive nanostructural coating design that enhance beneficial natural processes are outlined. The coatings exhibit emergent behavior during operation when their improved features work as a whole. In this way, as higher-ordered systems, they achieve multifunctionality and high wear

  17. Interpreting problematic behavior: systematic compensatory adaptations as emergent phenomena in autism.

    PubMed

    Damico, Jack S; Nelson, Ryan L

    2005-01-01

    Based upon an emergent account of pragmatic ability and disability, this article provides theoretical and empirical support for a conceptually deeper understanding of some systematic behaviors that have served as diagnostic indices in communicatively impaired populations. Specifically, by employing conversation analysis, several examples of problematic behaviors in autism are analysed as a specific type of compensatory adaptation. Theoretical and clinical implications are discussed.

  18. Dialectical Behavior Therapy Adapted for the Vocational Rehabilitation of Significantly Disabled Mentally Ill Adults

    ERIC Educational Resources Information Center

    Koons, Cedar R.; Chapman, Alexander L.; Betts, Bette B.; O'Rourke, Beth; Morse, Nesha; Robins, Clive J.

    2006-01-01

    Twelve vocational rehabilitation clients with severe mental illness received a comprehensive adaptation of dialectical behavior therapy (DBT) delivered in a group format. Treatment consisted of 2 hours of standard DBT skills training per week and 90 minutes of diary card review, chain analysis, and behavioral rehearsal. Participants were selected…

  19. Researching Travel Behavior and Adaptability: Using a Virtual Reality Role-Playing Game

    ERIC Educational Resources Information Center

    Watcharasukarn, Montira; Krumdieck, Susan; Green, Richard; Dantas, Andre

    2011-01-01

    This article describes a virtual reality role-playing game that was developed as a survey tool to collect travel behavior data and explore and monitor travel behavior adaptation. The Advanced Energy and Material Systems Laboratory has designed, developed a prototype, and tested such a game platform survey tool, called Travel Activity Constraint…

  20. Making Sense by Building Sense: Kindergarten Children's Construction and Understanding of Adaptive Robot Behaviors

    ERIC Educational Resources Information Center

    Mioduser, David; Levy, Sharona T.

    2010-01-01

    This study explores young children's ability to construct and explain adaptive behaviors of a behaving artifact, an autonomous mobile robot with sensors. A central component of the behavior construction environment is the RoboGan software that supports children's construction of spatiotemporal events with an a-temporal rule structure. Six…

  1. Boldness behavior and stress physiology in a novel urban environment suggest rapid correlated evolutionary adaptation

    PubMed Central

    Cardoso, Gonçalo C.; Whittaker, Danielle J.; Campbell-Nelson, Samuel; Robertson, Kyle W.; Ketterson, Ellen D.

    2012-01-01

    Novel or changing environments expose animals to diverse stressors that likely require coordinated hormonal and behavioral adaptations. Predicted adaptations to urban environments include attenuated physiological responses to stressors and bolder exploratory behaviors, but few studies to date have evaluated the impact of urban life on codivergence of these hormonal and behavioral traits in natural systems. Here, we demonstrate rapid adaptive shifts in both stress physiology and correlated boldness behaviors in a songbird, the dark-eyed junco, following its colonization of a novel urban environment. We compared elevation in corticosterone (CORT) in response to handling and flight initiation distances in birds from a recently established urban population in San Diego, California to birds from a nearby wildland population in the species' ancestral montane breeding range. We also measured CORT and exploratory behavior in birds raised from early life in a captive common garden study. We found persistent population differences for both reduced CORT responses and bolder exploratory behavior in birds from the colonist population, as well as significant negative covariation between maximum CORT and exploratory behavior. Although early developmental effects cannot be ruled out, these results suggest contemporary adaptive evolution of correlated hormonal and behavioral traits associated with colonization of an urban habitat. PMID:22936840

  2. Use of Vineland Adaptive Behavior Scales-II in Children with Autism--An Indian Experience

    ERIC Educational Resources Information Center

    Manohari, S. M.; Raman, Vijaya; Ashok, M. V.

    2013-01-01

    The Vineland Adaptive Behavior Scales-II Edition 2005 (Vineland-II) is useful in assessing abilities in autism spectrum disorder, where an accurate assessment of intelligence using standardized tools is difficult both due to the unique social and communication difficulties that these children present with and the behavioral issues that occur as…

  3. Visual Behaviors and Adaptations Associated with Cortical and Ocular Impairment in Children.

    ERIC Educational Resources Information Center

    Jan, J. E.; Groenveld, M.

    1993-01-01

    This article shows the usefulness of understanding visual behaviors in the diagnosis of various types of visual impairments that are due to ocular and cortical disorders. Behaviors discussed include nystagmus, ocular motor dyspraxia, head position, close viewing, field loss adaptations, mannerisms, photophobia, and abnormal color perception. (JDD)

  4. Studying adaptation and homeostatic behaviors of kinetic networks by using MATLAB.

    PubMed

    Drengstig, Tormod; Kjosmoen, Thomas; Ruoff, Peter

    2011-01-01

    Organisms have the ability to counteract environmental perturbations and keep certain components within a cell homeostatically regulated. Closely related to homeostasis is the behavior of perfect adaptation where an organism responds to a step-wise perturbation by regulating some of its components, after a transient period, to their original pre-perturbation values. A particular interesting type of model relates to the so-called robust behavior where the homeostatic or perfect adaptation property is independent of the magnitude of the applied step-wise perturbation. It has been shown that this type of behavior is related to the control-theoretic concept of integral feedback (or integral control). Using downloadable MATLAB examples, we demonstrate how robust perfect adaptation sites can be identified in reaction kinetic networks by linearizing the system, applying the Laplace transform and inspecting the transfer function. We also show how the homeostatic set point in perfect adaptation is related to the presence of zero-order fluxes.

  5. Modeling the Mechanical Behavior of Ceramic Matrix Composite Materials

    NASA Technical Reports Server (NTRS)

    Jordan, William

    1998-01-01

    Ceramic matrix composites are ceramic materials, such as SiC, that have been reinforced by high strength fibers, such as carbon. Designers are interested in using ceramic matrix composites because they have the capability of withstanding significant loads while at relatively high temperatures (in excess of 1,000 C). Ceramic matrix composites retain the ceramic materials ability to withstand high temperatures, but also possess a much greater ductility and toughness. Their high strength and medium toughness is what makes them of so much interest to the aerospace community. This work concentrated on two different tasks. The first task was to do an extensive literature search into the mechanical behavior of ceramic matrix composite materials. This report contains the results of this task. The second task was to use this understanding to help interpret the ceramic matrix composite mechanical test results that had already been obtained by NASA. Since the specific details of these test results are subject to the International Traffic in Arms Regulations (ITAR), they are reported in a separate document (Jordan, 1997).

  6. Effects of Fiber Coating Composition on Mechanical Behavior of Silicon Carbide Fiber-Reinforced Celsian Composites

    NASA Technical Reports Server (NTRS)

    Bansal, Narottam P.; Elderidge, Jeffrey I.

    1998-01-01

    Celsian matrix composites reinforced with Hi-Nicalon fibers, precoated with a dual layer of BN/SiC by chemical vapor deposition in two separate batches, were fabricated. Mechanical properties of the composites were measured in three-point flexure. Despite supposedly identical processing, the composite panels fabricated with fibers coated in two batches exhibited substantially different mechanical behavior. The first matrix cracking stresses (sigma(sub mc)) of the composites reinforced with fibers coated in batch 1 and batch 2 were 436 and 122 MPa, respectively. This large difference in sigma(sub mc) was attributed to differences in fiber sliding stresses(tau(sub friction)), 121.2+/-48.7 and 10.4+/-3.1 MPa, respectively, for the two composites as determined by the fiber push-in method. Such a large difference in values of tau(sub friction) for the two composites was found to be due to the difference in the compositions of the interface coatings. Scanning Auger microprobe analysis revealed the presence of carbon layers between the fiber and BN, and also between the BN and SiC coatings in the composite showing lower tau(sub friction). This resulted in lower sigma(sub mc) in agreement with the ACK theory. The ultimate strengths of the two composites, 904 and 759 MPa, depended mainly on the fiber volume fraction and were not significantly effected by tau(sub friction) values, as expected. The poor reproducibility of the fiber coating composition between the two batches was judged to be the primary source of the large differences in performance of the two composites.

  7. Adaptive and maladaptive behavior in children with Smith-Magenis Syndrome.

    PubMed

    Martin, Staci C; Wolters, Pamela L; Smith, Ann C M

    2006-05-01

    Children with Smith-Magenis Syndrome (SMS) exhibit deficits in adaptive behavior but systematic studies using objective measures are lacking. This descriptive study assessed adaptive functioning in 19 children with SMS using the Vineland Adaptive Behavior Scales (VABS). Maladaptive behavior was examined through parent questionnaires and the Childhood Autism Rating Scale. Cognitive functioning was evaluated with an age-appropriate test. Children scored below average on VABS Communication, Daily Living Skills, and Socialization scales. Learning problems and hyperactivity scales on the Conner's Parent Rating Scale were elevated, and girls were more impulsive than boys. Stereotypic and self-injurious behaviors were present in all children. Cognitive functioning was delayed and consistent with communication and daily living skills, while socialization scores were higher than IQ.

  8. Processing and mechanical behavior of aluminium oxide microstructure composites

    NASA Astrophysics Data System (ADS)

    Pavlacka, Robert J.

    We have proposed a new class of composites that accesses different component properties not through the use of distinct materials, but through the exploitation of the microstructure-property relationship within a single material. That is, we seek to adapt composite concepts to take advantage of the considerable variance in properties associated with different microstructures. This new class of composites is called microstructure composites. Microstructure composites are predominately single phase ceramics that utilize multiple distinct microstructure features in the same composite to obtain unique property combinations. Spatial control and composite connectivity of the individual microstructure components of a microstructure composite are ultimately the key to developing and controlling useful and unique properties. Microstructural features can be controlled via the starting location and transport of the dopants, minority second phases, and liquid phases that are used to manipulate microstructure development. This work focuses on textured-equiaxed microstructure in the Al2O 3 system. Texture is obtained in situ using templated grain growth (TGG). To control microstructure development locally during microstructure composite fabrication, it is important to use relatively low levels of dopant to mitigate the effects of dopant interdiffusion. Therefore, the development of texture in alpha-Al2O3 using TGG was explored under low liquid-phase dopant concentration conditions. High temperature dilatometry was performed to quantify the effect of template constraint on x-y plane shirinkage and the extent to which this constraint could be mitigated as a function of the dopant concentration. x-y plane shrinkage was observed to be increasingly constrained with increasing template loading and decreasing dopant concentration. Final x-y plane shrinkage was greater for samples with 0.14 wt% dopant than for those without dopant, despite have a much lower peak strain rate. It was

  9. Increasing adaptive behavior skill deficits from childhood to adolescence in autism spectrum disorder: role of executive function.

    PubMed

    Pugliese, Cara E; Anthony, Laura; Strang, John F; Dudley, Katerina; Wallace, Gregory L; Kenworthy, Lauren

    2015-06-01

    Almost half of all children with autism spectrum disorder have average cognitive abilities, yet outcome remains poor. Because outcome in HFASD is more related to adaptive behavior skills than cognitive level it is important to identify predictors of adaptive behavior. This study examines cognitive and demographic factors related to adaptive behavior, with specific attention to the role of executive function (EF) in youth with HFASD aged 4-23. There was a negative relationship between age and adaptive behavior and the discrepancy between IQ and adaptive behavior increased with age. EF problems contributed to lower adaptive behavior scores across domains. As such, it is important to target adaptive skills, and the EF problems that may contribute to them, in youth with HFASD.

  10. Literacy and cultural adaptations for cognitive behavioral therapy in a rural pain population.

    PubMed

    Kuhajda, Melissa C; Thorn, Beverly E; Gaskins, Susan W; Day, Melissa A; Cabbil, Chalanda M

    2011-06-01

    Low literacy and chronic pain have been identified as significant problems in the rural USA. Cognitive behavioral therapy (CBT) is a widely used efficacious psychosocial treatment for chronic pain; adaptations for low-literacy rural populations are lacking. This paper reports on preparatory steps implemented to address this deficit. Adapting an existing group, CBT patient workbook for rural adults with low literacy is described, and adaptations to reduce cognitive demand inherent in CBT are explained via cognitive load theory. Adhering to health literacy guidelines, the patient workbook readability was lowered to the fifth grade. Two key informant interviews and four focus groups provided the impetus for structural and procedural adaptations. Using health literacy guidelines and participant feedback, the patient workbook and treatment approach were adapted for implementation in low-literacy rural adult chronic pain populations, setting the stage for proceeding with a larger trial using the adapted materials.

  11. Multigroup Confirmatory Factor Analysis for the Teacher Form, Ages 5 to 21, of the Adaptive Behavior Assessment System-II

    ERIC Educational Resources Information Center

    Aricak, O. Tolga; Oakland, Thomas

    2010-01-01

    The American Association on Intellectual and Developmental Disabilities has promulgated various models of adaptive behavior, including its 1992 model that highlighted 10 adaptive skills and its 2002 model that highlighted three conceptual domains. The Adaptive Behavior Assessment System-II (ABAS-II) was designed to be consistent with these models.…

  12. Pressure-composition-isotherm behaviors of MgHx-BCY composites by reactive mechanical alloying

    NASA Astrophysics Data System (ADS)

    Lee, Soo-Sun; Lee, Na-Ri; Kim, Kyeong-Il; Hong, Tae-Whan

    2013-11-01

    The aim of the present paper is to report results on hydrogenation behavior of a new composite material, MgHx-BCY10. Rare earth element-doped ABO3 perovskite oxides have been studied for their possibility use in hydrogen storage. Especially, materials based on BaCeO3 are known not only for their proton conductivity in hydrogen but also for the fact that they have higher hydrogen solubility than that of other metal oxides. So, the admixing of perovskite-type oxide in storage materials has to consider the possibility of MgHx leading to sorption kinetics. And, these materials can be new materials for hydrogen storage. This research considers Pressure-Composition-Isothermal behavior according to perovskite-type oxide powder ratio and hydrogen pressure. The effects of added amount of BCY show a temperature of dehydrogenation that has decreased.From the results shown in the P-C-T curves, the MgHx-5wt% BCY composite was evaluated as having a 2.81 wt% maximum hydrogen storage capacity at 623 K. The absorption curves show that the MgHx-10wt% BCY was composite evaluated at a maximum 0.43wt%/s hydrogen absorption rate at 623 K. From the results of the hydrogenation behavior observed, the role of BCY as a catalyst in hydrogen absorption is confirmed.

  13. Aggression and Adaptive Functioning: The Bright Side to Bad Behavior.

    ERIC Educational Resources Information Center

    Hawley, Patricia H.; Vaughn, Brian E.

    2003-01-01

    Asserts that effective children and adolescents can engage in socially undesirable behavior to attain personal goals at relatively little personal or interpersonal cost, implying that relations between adjustment and aggression may not be optimally described by standard linear models. Suggests that if researchers recognize that some aggression…

  14. Musical Aptitude and Adaptive Behavior of People with Mental Retardation.

    ERIC Educational Resources Information Center

    Miller, Leon K.; Monroe, Melinda J.

    1990-01-01

    Musical aptitude and behavioral adjustment were assessed in 16 mentally retarded adults nominated as having special musical interests and/or skills. Evidence of difficulties in adjustment associated with musical skill or interest was mixed, though results suggested no pervasive maladjustment among those with exceptional skill combined with mental…

  15. Profiles of classroom behavior in high schools: associations with teacher behavior management strategies and classroom composition.

    PubMed

    Pas, Elise T; Cash, Anne H; O'Brennan, Lindsey; Debnam, Katrina J; Bradshaw, Catherine P

    2015-04-01

    Although there has been considerable attention to the issue of classroom management and processes in educational reform models, there has been relatively limited research on these factors in high schools. The current study utilized observational data from 1262 classrooms in 52 high schools to examine teacher classroom management strategies and ratings of student compliance, engagement, and social disruption. Latent profile analysis (LPA) was conducted to examine specific patterns of classroom-wide student behavior in relation to teachers' use of classroom management strategies and classroom composition. The LPA revealed three distinct classroom behavioral profiles where students consistently met behavioral expectations (71%), inconsistently met expectations (23%), and were noncompliant (6%). Analyses indicated a functional association between patterns of student behavior and teachers' classroom management. In classrooms where students consistently met expectations, teachers provided more opportunities to respond and less disapproval and reactive behavioral management. Classrooms with noncompliant students had teachers who used the most disapproval and reactive behavior management. In addition, classrooms characterized as consistent had fewer males and more White students than classrooms characterized by inconsistent and noncompliant behaviors. These findings highlight the link between student patterns of behavior and teacher classroom management and have important implications for screening and professional development.

  16. Systematic Review of Engagement in Culturally Adapted Parent Training for Disruptive Behavior

    PubMed Central

    Butler, Ashley M.; Titus, Courtney

    2016-01-01

    This article reviews the literature reporting engagement (enrollment, attendance, and attrition) in culturally adapted parent training for disruptive behavior among racial/ethnic minority parents of children ages 2–7 years. The review describes the reported rates of engagement in adapted interventions and how engagement is analyzed in studies, methods to develop adaptations, and adaptations that have been implemented. Seven studies were identified. Parental engagement varied across and within studies. Only one study examined whether adaptations improved engagement compared to non-adapted intervention. Frequent methods to develop adaptations were building partnerships or conducting interviews/focus groups with minority parents or community members. Adaptations included addressing cultural beliefs (perceptions of parenting skills), values (interdependence), or experiences (immigration) that affect parenting or receptivity to interventions; ensuring racial/ethnic diversity of interventionists; and addressing cultural relevancy and literacy level of materials. Future research should examine engagement in adapted interventions compared to non-adapted interventions and examine factors (e.g., immigration status) that may moderate impact on engagement. PMID:27429537

  17. Composite Panel Postbuckling Behavior and General Model of Joints in Composite Structures

    NASA Technical Reports Server (NTRS)

    Zamula, G. N.; Kutinov, V. F.; Vasilyev, V. V.; Grishin, V. I.; Ierusalimsky, K. M.; Azikov, N. S.; Begeyev, T. K.

    1996-01-01

    The present paper is a final technical report on the research programme NCCW-73 accomplished within co-operation between NASA of the USA and GOSKOMOBORONPROM of Russia in the field of aeronautics. The report contains basic results of studies in two areas, 'Analysis of postbuckling behavior of composite panels' and 'Development of general model of joints in composite structures'; these results were obtained in conformity with requirements of NCCW-73. In addition, consideration is given to some related issues, and proposals for further studies are formulated.

  18. Effects of Behavior Support Team Composition on the Technical Adequacy and Contextual Fit of Behavior Support Plans

    ERIC Educational Resources Information Center

    Benazzi, Leah; Horner, Robert H.; Good, Roland H.

    2006-01-01

    This study examined how the composition of a behavior support team affected use of assessment information in the design of behavior support plans. Specifically, we examined if typical teams designed behavior support plans that differed in (a) technical adequacy and/or (b) contextual fit when (1) teams did not include behavior specialists, (2)…

  19. Adaptive Control Responses to Behavioral Perturbation Based Upon the Insect

    DTIC Science & Technology

    2006-11-01

    autonomous robot Soc Neuroci Abstr CD ROM 31: :176.110 Harley CM, Predina JD, Ritzmann RE (2006) Responses to incomplete sensory information in cockroach...climbing behavior. Soc Neuroci Abstr CD ROM 32:449.412 Hess D, Buschges A (1999) Role of proprioceptive signals from an insect femur-tibia joint in...Altered joint reflexes in the cockroach may lead to 17 directional changes in leg extension. Soc Neuroci Abstr CD ROM 32:449.411 Pollack AJ

  20. Adapting Autonomous Behavior Using an Inverse Trust Estimation

    DTIC Science & Technology

    2014-07-01

    to achieve team goals. Trustworthy behavior is not something that can be programmed into an agent in advance since how humans measure trust may be task...Inverse Trust Estimation 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S) 5d. PROJECT NUMBER 5e. TASK NUMBER 5f. WORK...wheeled unmanned ground vehicle (UGV) and uses eBotwork’s built-in natural language processing (for interpreting user commands), locomotion, and path

  1. Cognitive, adaptive, and behavioral features in Joubert syndrome.

    PubMed

    Bulgheroni, Sara; D'Arrigo, Stefano; Signorini, Sabrina; Briguglio, Marilena; Di Sabato, Maria Lucia; Casarano, Manuela; Mancini, Francesca; Romani, Marta; Alfieri, Paolo; Battini, Roberta; Zoppello, Marina; Tortorella, Gaetano; Bertini, Enrico; Leuzzi, Vincenzo; Valente, Enza Maria; Riva, Daria

    2016-12-01

    Joubert syndrome (JS) is a recessive neurodevelopmental disorder characterized by a distinctive cerebellar and brainstem malformation recognizable on brain imaging, the so-called molar tooth sign. The full spectrum of cognitive and behavioral phenotypes typical of JS is still far from being elucidated. The aim of this multicentric study was to define the clinical phenotype and neurobehavioral features of a large cohort of subjects with a neuroradiologically confirmed diagnosis of JS. Fifty-four patients aged 10 months to 29 years were enrolled. Each patient underwent a neurological evaluation as well as psychiatric and neuropsychological assessments. Global cognitive functioning was remarkably variable with Full IQ/General Quotient ranging from 32 to 129. Communication skills appeared relatively preserved with respect to both Daily Living and Socialization abilities. The motor domain was the area of greatest vulnerability, with a negative impact on personal care, social, and academic skills. Most children did not show maladaptive behaviors consistent with a psychiatric diagnosis but approximately 40% of them presented emotional and behavioral problems. We conclude that intellectual disability remains a hallmark but cannot be considered a mandatory diagnostic criterion of JS. Despite the high variability in the phenotypic spectrum and the extent of multiorgan involvement, nearly one quarter of JS patients had a favorable long-term outcome with borderline cognitive deficit or even normal cognition. Most of JS population also showed relatively preserved communication skills and overall discrete behavioral functioning in everyday life, independently from the presence and/or level of intellectual disability. © 2016 Wiley Periodicals, Inc.

  2. Resistance to exercise-induced weight loss: compensatory behavioral adaptations.

    PubMed

    Melanson, Edward L; Keadle, Sarah Kozey; Donnelly, Joseph E; Braun, Barry; King, Neil A

    2013-08-01

    In many interventions that are based on an exercise program intended to induce weight loss, the mean weight loss observed is modest and sometimes far less than what the individual expected. The individual responses are also widely variable, with some individuals losing a substantial amount of weight, others maintaining weight, and a few actually gaining weight. The media have focused on the subpopulation that loses little weight, contributing to a public perception that exercise has limited utility to cause weight loss. The purpose of the symposium was to present recent, novel data that help explain how compensatory behaviors contribute to a wide discrepancy in exercise-induced weight loss. The presentations provide evidence that some individuals adopt compensatory behaviors, that is, increased energy intake and/or reduced activity, that offset the exercise energy expenditure and limit weight loss. The challenge for both scientists and clinicians is to develop effective tools to identify which individuals are susceptible to such behaviors and to develop strategies to minimize their effect.

  3. The behavior of bonded doubler splices for composite sandwich panels

    NASA Technical Reports Server (NTRS)

    Zeller, T. A.; Weisahaar, T. A.

    1980-01-01

    The results of an investigation into the behavior of adhesively bonded doubler splices of two composite material sandwich panels are presented. The splices are studied from three approaches: analytical; numerical (finite elements); and experimental. Several parameters that characterize the splice are developed to determine their influence upon joint strength. These parameters are: doubler overlap length; core stiffness; laminate bending stiffness; the size of the gap between the spliced sandwich panels; and room and elevated temperatures. Similarities and contrasts between these splices and the physically similar single and double lap joints are discussed. The results of this investigation suggest several possible approaches to improving the strength of the sandwich splices.

  4. Fracture behavior of notched sheet-molding-compound composites

    NASA Astrophysics Data System (ADS)

    Nagoh, Satoshi; Choi, Nak-Sam; Takahashi, Kiyoshi

    1992-05-01

    The effect of notched tip radius on the fracture behavior of compact tension type specimens of sheet-molding compound composites was studied. For specimens were rho of 0.56 or less, a main crack initiated at the notch tip and grew in parallel with the generation of many subcracks surrounding the main crack tip. For rho of 2.1 mm, subcracks propagated in radial directions during main crack growth. With increasing notch tip radius, little increase in the maximum load, acoustic emission (AE) cumulative event count, and standard deviations of AE source locations was observed.

  5. Brainstem correlates of behavioral and compositional preferences of musical harmony.

    PubMed

    Bidelman, Gavin M; Krishnan, Ananthanarayan

    2011-03-30

    Certain chords are preferred by listeners behaviorally and also occur with higher regularity in musical composition. Event-related potentials index the perceived consonance (i.e., pleasantness) of musical pitch relationships providing a cortical neural correlate for such behavioral preferences. Here, we show correlates of these harmonic preferences exist at subcortical stages of audition. Brainstem frequency-following responses were measured in response to four prototypical musical triads. Pitch salience computed from frequency-following responses correctly predicted the ordering of triadic harmony stipulated by music theory (i.e., major >minor >diminished >augmented). Moreover, neural response magnitudes showed high correspondence with listeners' perceptual ratings of the same chords. Results suggest that preattentive stages of pitch processing may contribute to perceptual judgments of musical harmony.

  6. Thermal Degradation and Combustion Behavior of Polypropylene/MWCNT Composites

    NASA Astrophysics Data System (ADS)

    Zaikov, G. E.; Rakhimkulov, A. D.; Lomakin, S. M.; Dubnikova, I. L.; Shchegolikhin, A. N.; Davidov, E. Ya.

    2010-06-01

    Studies of thermal and fire-resistant properties of the polypropylene/multi-walled carbon nanotube composites (PP/MWCNT) prepared by means of melt intercalation are discussed. The sets of the data acquired with the aid of non-isothermal TG experiments have been treated by the model kinetic analysis. The thermal-oxidative degradation behavior of PP/MWCNT and stabilizing effect caused by addition of MWCNT has been investigated by means of TGA and EPR spectroscopy. The results of cone calorimetric tests lead to the conclusion that char formation plays a key role in the mechanism of flame retardation for nanocomposites. This could be explained by the specific antioxidant properties and high thermal conductivity of MWCNT which determine high-performance carbonization during thermal degradation process. Comparative analysis of the flammability characteristics for PP-clay/MWCNT nanocomposites was provided in order to emphasize the specific behavior of the nanocomposites under high-temperature tests.

  7. Adaptive behaviors in multi-agent source localization using passive sensing

    PubMed Central

    Shaukat, Mansoor; Chitre, Mandar

    2016-01-01

    In this paper, the role of adaptive group cohesion in a cooperative multi-agent source localization problem is investigated. A distributed source localization algorithm is presented for a homogeneous team of simple agents. An agent uses a single sensor to sense the gradient and two sensors to sense its neighbors. The algorithm is a set of individualistic and social behaviors where the individualistic behavior is as simple as an agent keeping its previous heading and is not self-sufficient in localizing the source. Source localization is achieved as an emergent property through agent’s adaptive interactions with the neighbors and the environment. Given a single agent is incapable of localizing the source, maintaining team connectivity at all times is crucial. Two simple temporal sampling behaviors, intensity-based-adaptation and connectivity-based-adaptation, ensure an efficient localization strategy with minimal agent breakaways. The agent behaviors are simultaneously optimized using a two phase evolutionary optimization process. The optimized behaviors are estimated with analytical models and the resulting collective behavior is validated against the agent’s sensor and actuator noise, strong multi-path interference due to environment variability, initialization distance sensitivity and loss of source signal. PMID:28018121

  8. Adaptive behaviors in multi-agent source localization using passive sensing.

    PubMed

    Shaukat, Mansoor; Chitre, Mandar

    2016-12-01

    In this paper, the role of adaptive group cohesion in a cooperative multi-agent source localization problem is investigated. A distributed source localization algorithm is presented for a homogeneous team of simple agents. An agent uses a single sensor to sense the gradient and two sensors to sense its neighbors. The algorithm is a set of individualistic and social behaviors where the individualistic behavior is as simple as an agent keeping its previous heading and is not self-sufficient in localizing the source. Source localization is achieved as an emergent property through agent's adaptive interactions with the neighbors and the environment. Given a single agent is incapable of localizing the source, maintaining team connectivity at all times is crucial. Two simple temporal sampling behaviors, intensity-based-adaptation and connectivity-based-adaptation, ensure an efficient localization strategy with minimal agent breakaways. The agent behaviors are simultaneously optimized using a two phase evolutionary optimization process. The optimized behaviors are estimated with analytical models and the resulting collective behavior is validated against the agent's sensor and actuator noise, strong multi-path interference due to environment variability, initialization distance sensitivity and loss of source signal.

  9. A Compositional Relevance Model for Adaptive Information Retrieval

    NASA Technical Reports Server (NTRS)

    Mathe, Nathalie; Chen, James; Lu, Henry, Jr. (Technical Monitor)

    1994-01-01

    There is a growing need for rapid and effective access to information in large electronic documentation systems. Access can be facilitated if information relevant in the current problem solving context can be automatically supplied to the user. This includes information relevant to particular user profiles, tasks being performed, and problems being solved. However most of this knowledge on contextual relevance is not found within the contents of documents, and current hypermedia tools do not provide any easy mechanism to let users add this knowledge to their documents. We propose a compositional relevance network to automatically acquire the context in which previous information was found relevant. The model records information on the relevance of references based on user feedback for specific queries and contexts. It also generalizes such information to derive relevant references for similar queries and contexts. This model lets users filter information by context of relevance, build personalized views of documents over time, and share their views with other users. It also applies to any type of multimedia information. Compared to other approaches, it is less costly and doesn't require any a priori statistical computation, nor an extended training period. It is currently being implemented into the Computer Integrated Documentation system which enables integration of various technical documents in a hypertext framework.

  10. Complex Features in Lotka-Volterra Systems with Behavioral Adaptation

    NASA Astrophysics Data System (ADS)

    Tebaldi, Claudio; Lacitignola, Deborah

    Lotka-Volterra systems have played a fundamental role for mathematical modelling in many branches of theoretical biology and proved to describe, at least qualitatively, the essential features of many phenomena, see for example Murray [Murray 2002]. Furthermore models of that kind have been considered successfully also in quite different and less mathematically formalized context: Goodwin' s model of economic growth cycles [Goodwin 1967] and urban dynamics [Dendrinos 1992] are only two of a number of examples. Such systems can certainly be defined as complex ones and in fact the aim of modelling was essentially to clarify mechanims rather than to provide actual precise simulations and predictions. With regards to complex systems, we recall that one of their main feature, no matter of the specific definition one has in mind, is adaptation, i. e. the ability to adjust.

  11. Static and quasi-static behavior of an adaptive system to compensate path errors for smart fiber placement

    NASA Astrophysics Data System (ADS)

    Perner, M.; Monner, H. P.; Krombholz, C.; Kruse, F. F.

    2015-04-01

    Smart fiber placement is an ambitious topic in current research for automated manufacturing of large-scale composite structures, e.g. wing covers. Adaptive systems get in focus to obtain a high degree of observability and controllability of the manufacturing process. In particular, vibrational issues and material failure have to be studied to significantly increase the production rate with no loss in accuracy of the fiber layup. As one contribution, an adaptive system has been developed to be integrated into the fiber placement head. It decouples the compaction roller from disturbances caused by misalignments, varying components' behavior over a large work area and acceleration changes during operation. Therefore, the smart system axially adapts the position of the compaction roller in case of disturbances. This paper investigates the behavior of the system to compensate quasi-static deviations from the desired path. In particular, the compensation efficiency of a constant offset, a linear drift with constant gradient and a single-curved drift is studied. Thus, the test bed with measurement devices and scenarios is explained. Based on the knowledge obtained by the experimental data, the paper concludes with a discussion of the proposed approach for its use under operating conditions and further implementation.

  12. Convergent Aeronautics Solutions (CAS) Showcase Presentation on Mission Adaptive Digital Composite Aerostructure Technologies (MADCAT)

    NASA Technical Reports Server (NTRS)

    Swei, Sean; Cheung, Kenneth

    2016-01-01

    This project is to develop a novel aerostructure concept that takes advantage of emerging digital composite materials and manufacturing methods to build high stiffness-to-density ratio, ultra-light structures that can provide mission adaptive and aerodynamically efficient future N+3N+4 air vehicles.

  13. Composition of Estonian Infants' Expressive Lexicon According to the Adaptation of CDI/Words and Gestures

    ERIC Educational Resources Information Center

    Schults, Astra; Tulviste, Tiia

    2016-01-01

    The growth rate and the composition of expressive lexicon was studied in a sample of 903 infants between the age of 0;8 and 1;4 whose parents completed the Estonian adaptation of the MacArthur-Bates Communicative Development Inventory-Words and Gestures. As expected, older children had on average larger vocabularies compared to younger children.…

  14. Flight Test of Composite Model Reference Adaptive Control (CMRAC) Augmentation Using NASA AirSTAR Infrastructure

    NASA Technical Reports Server (NTRS)

    Gregory, Irene M.; Gadient, ROss; Lavretsky, Eugene

    2011-01-01

    This paper presents flight test results of a robust linear baseline controller with and without composite adaptive control augmentation. The flight testing was conducted using the NASA Generic Transport Model as part of the Airborne Subscale Transport Aircraft Research system at NASA Langley Research Center.

  15. Lateral cascade of indirect effects in food webs with different types of adaptive behavior.

    PubMed

    Kamran-Disfani, Ahmad R; Golubski, Antonio J

    2013-12-21

    It is widely recognized that indirect effects due to adaptive behaviors can have important effects on food webs. One consequence may be to change how readily perturbations propagate through the web, because species' behaviors as well as densities may respond to perturbations. It is not well understood which types of behavior are more likely to facilitate versus inhibit propagation of disturbances through a food web, or how this might be affected by the shape of a food web or the patterns of interaction strengths within it. We model two simple, laterally expanded food webs (one with three trophic levels and one with four), and compare how various adaptive behaviors affect the potential for a newly introduced predator to change the equilibrium densities of distant species. Patterns of changes in response to the introduction were qualitatively similar across most models, as were the ways in which patterns of direct interaction strengths affected those responses. Depending on both the web structure and the specific adaptive behavior, the potential for density changes to propagate through the web could be either increased or diminished relative to the no-behavior model. Two behaviors allowed density changes to propagate through a four-level web that precluded such propagation in the no-behavior model, and each of these two behaviors led to qualitatively different patterns of density changes. In the one model (diet choice) in which density changes were able to propagate in both web structures, patterns of density changes differed qualitatively between webs. Some of our results flowed from the fact that behaviors did not interact directly in the systems we considered, so that indirect effects on distant species had to be at least partly density-mediated. Our models highlight this as an inherent limitation of considering in isolation behaviors that are strictly foraging-related or strictly defense-related, making a case for the value of simultaneously considering multiple

  16. The adaptive trade-off between detection and discrimination in cortical representations and behavior.

    PubMed

    Ollerenshaw, Douglas R; Zheng, He J V; Millard, Daniel C; Wang, Qi; Stanley, Garrett B

    2014-03-05

    It has long been posited that detectability of sensory inputs can be sacrificed in favor of improved discriminability and that sensory adaptation may mediate this trade-off. The extent to which this trade-off exists behaviorally and the complete picture of the underlying neural representations that likely subserve the phenomenon remain unclear. In the rodent vibrissa system, an ideal observer analysis of cortical activity measured using voltage-sensitive dye imaging in anesthetized animals was combined with behavioral detection and discrimination tasks, thalamic recordings from awake animals, and computational modeling to show that spatial discrimination performance was improved following adaptation, but at the expense of the ability to detect weak stimuli. Together, these results provide direct behavioral evidence for the trade-off between detectability and discriminability, that this trade-off can be modulated through bottom-up sensory adaptation, and that these effects correspond to important changes in thalamocortical coding properties.

  17. Measuring adaptations of motivational interviewing: the development and validation of the behavior change counseling index (BECCI).

    PubMed

    Lane, Claire; Huws-Thomas, Michelle; Hood, Kerenza; Rollnick, Stephen; Edwards, Karen; Robling, Michael

    2005-02-01

    One of the most common challenges faced by health professionals is encouraging patients to change their behavior to improve their health. This paper reports the development of a checklist, the behavior change counseling index (BECCI). This aims to measure practitioner competence in behavior change counseling (BCC), an adaptation of motivational interviewing suitable for brief consultations in healthcare settings. The checklist has demonstrated acceptable levels of validity, reliability and responsiveness, and aims to assist trainers and researchers in assessing change in practitioner behavior before, during and after training in BCC. BECCI will also provide valuable information about the standard of BCC that practitioners were trained to deliver in studies of BCC as an intervention.

  18. Nonequilibrium material effects on the behavior of polymeric composite matrices and their related composites

    NASA Technical Reports Server (NTRS)

    Wilkes, G. L.

    1982-01-01

    The effects of physical aging on the material properties of some linear and network macromolecular glasses are discussed. The free volume concept is used to describe this behavior. The effect of physical aging on properties of some uniaxial graphite/fiber epoxy resin composites is investigated using stress relaxation in both tensile and flexural modes. The matrix polymers used were resins both of which are based on a 4,4-methylenedianiline derivative of epichlorohydrin with diamino diphenyl sulfone (DDS) as the curing agent. The matrix resin, as used in the practical application in composites, not fully cured and the glass transition of the network was dependent on the curing schedule. The physical aging of the bulk crosslinked epoxy was found to depend on the annealing temperature, and the T sub g of the resin. The physical aging of the composite, monitored by the stress relaxation method, was found to be dependent on the testing direction.

  19. ADAPTIVE BEHAVIORS IN YOUNG CHILDREN: A UNIQUE CULTURAL COMPARISON IN ITALY

    PubMed Central

    Taverna, Livia; Bornstein, Marc H.; Putnick, Diane L.; Axia, Giovanna

    2010-01-01

    On account of a series of unique historical events, the present-day denizens of South Tyrol inhabit a cultural, political, and linguistic autonomous region that intercalates Italians and Austrian/German Italians. We compared contemporary Italian and Austrian/German Italian girls' and boys' adaptive behaviors in everyday activities in this region. Using the Vineland Adaptive Behavior Scales, we first interviewed mothers about their children's communication, daily living, socialization, and motor skills. Main effects of local culture (and no interactions with gender) emerged: Austrian/German Italian children were rated higher than Italian children in both adaptive daily living and socialization skills. Next, we explored ethnic differences in childrearing. Austrian/German Italians reported fostering greater autonomy in their children than Italians, and children's autonomy was associated with their adaptive behavior. Children living in neighboring Italian and Austrian/German Italian cultural niches appear to experience subtle but consequentially different conditions of development that express themselves in terms of differing levels of adaptive behaviors. PMID:21532914

  20. Mobile and Wireless Technologies in Health Behavior and the Potential for Intensively Adaptive Interventions

    PubMed Central

    Riley, William T.; Serrano, Katrina J.; Nilsen, Wendy; Atienza, Audie A.

    2015-01-01

    Recent advances in mobile and wireless technologies have made real-time assessments of health behaviors and their influences possible with minimal respondent burden. These tech-enabled real-time assessments provide the basis for intensively adaptive interventions (IAIs). Evidence of such studies that adjust interventions based on real-time inputs is beginning to emerge. Although IAIs are promising, the development of intensively adaptive algorithms generate new research questions, and the intensive longitudinal data produced by IAIs require new methodologies and analytic approaches. Research considerations and future directions for IAIs in health behavior research are provided. PMID:26086033

  1. Mobile and Wireless Technologies in Health Behavior and the Potential for Intensively Adaptive Interventions.

    PubMed

    Riley, William T; Serrano, Katrina J; Nilsen, Wendy; Atienza, Audie A

    2015-10-01

    Recent advances in mobile and wireless technologies have made real-time assessments of health behaviors and their influences possible with minimal respondent burden. These tech-enabled real-time assessments provide the basis for intensively adaptive interventions (IAIs). Evidence of such studies that adjust interventions based on real-time inputs is beginning to emerge. Although IAIs are promising, the development of intensively adaptive algorithms generate new research questions, and the intensive longitudinal data produced by IAIs require new methodologies and analytic approaches. Research considerations and future directions for IAIs in health behavior research are provided.

  2. Mechanical behavior of a composite interface: Calcium-silicate-hydrates

    SciTech Connect

    Palkovic, Steven D.; Moeini, Sina; Büyüköztürk, Oral; Yip, Sidney

    2015-07-21

    The generalized stacking fault (GSF) is a conceptual procedure historically used to assess shear behavior of defect-free crystalline structures through molecular dynamics or density functional theory simulations. We apply the GSF technique to the spatially and chemically complex quasi-layered structure of calcium-silicate-hydrates (C-S-H), the fundamental nanoscale binder within cementitious materials. A failure plane is enforced to calculate the shear traction-displacement response along a composite interface containing highly confined water molecules, hydroxyl groups, and calcium ions. GSF simulations are compared with affine (homogeneous) shear simulations, which allow strain to localize naturally in response to the local atomic environment. Comparison of strength and deformation behavior for the two loading methods shows the composite interface controls bulk shear deformation. Both models indicate the maximum shear strength of C-S-H exhibits a normal-stress dependency typical of cohesive-frictional materials. These findings suggest the applicability of GSF techniques to inhomogeneous structures and bonding environments, including other layered systems such as biological materials containing organic and inorganic interfaces.

  3. Mechanical behavior of a composite interface: Calcium-silicate-hydrates

    NASA Astrophysics Data System (ADS)

    Palkovic, Steven D.; Moeini, Sina; Yip, Sidney; Büyüköztürk, Oral

    2015-07-01

    The generalized stacking fault (GSF) is a conceptual procedure historically used to assess shear behavior of defect-free crystalline structures through molecular dynamics or density functional theory simulations. We apply the GSF technique to the spatially and chemically complex quasi-layered structure of calcium-silicate-hydrates (C-S-H), the fundamental nanoscale binder within cementitious materials. A failure plane is enforced to calculate the shear traction-displacement response along a composite interface containing highly confined water molecules, hydroxyl groups, and calcium ions. GSF simulations are compared with affine (homogeneous) shear simulations, which allow strain to localize naturally in response to the local atomic environment. Comparison of strength and deformation behavior for the two loading methods shows the composite interface controls bulk shear deformation. Both models indicate the maximum shear strength of C-S-H exhibits a normal-stress dependency typical of cohesive-frictional materials. These findings suggest the applicability of GSF techniques to inhomogeneous structures and bonding environments, including other layered systems such as biological materials containing organic and inorganic interfaces.

  4. Fatigue behavior and recommended design rules for an automotive composite

    SciTech Connect

    Corum, J.M.; Battiste, R.L.; Ruggles, M.B.

    1998-11-01

    Fatigue curves (stress vs cycles to failure) were generated under a variety of conditions (temperatures, fluid environments, mean stresses, block loadings) for a candidate automotive structural composite. The results were used to (1) develop observations regarding basic fatigue behavioral characteristics and (2) establish fatigue design rules. The composite was a structural reaction injection-molded polyurethane reinforced with continuous strand, swirl-mat E-glass fibers. Tensile fatigue tests on specimens from a single plaque at {minus}40 F, room temperature, and 250 F provided the basic behavioral characteristics. It was found that when stress was normalized by the at-temperature ultimate tensile strength, the fatigue curves at the three temperatures collapsed into a single master curve. An assessment of the individual stress-strain loops throughout each test showed a progressive loss in stiffness and an increase in permanent strain, both of which are indicative of increasing damage. Fatigue tests on specimens from several plaques were used to develop a design fatigue curve, which was established by using a reduction factor of 20 on average cycles to failure. This factor assures that the stiffness loss during the design life is no greater than 10 percent. Fatigue reduction factors were established to account for various fluids. Reversed stress fatigue tests allowed a mean stress rule to be validated, and block loading tests were used to demonstrate the adequacy of Miner`s rule for cumulative fatigue damage.

  5. Using practical and social information to influence flood adaptation behavior

    NASA Astrophysics Data System (ADS)

    Allaire, Maura C.

    2016-08-01

    As the prospect for more frequent and severe extreme weather events gains scientific support, many nations are evaluating mitigation and adaptation options. Insurance and home retrofits could reduce household welfare losses due to flood events. Yet even after disasters, households often fail to take risk mitigation actions. This paper presents the first randomized field experiment that tests the effect of information provision on household uptake of flood insurance and home retrofits. A sample of 364 flood-prone households in Bangkok was randomly split into treatment and control groups. The treatment group received practical details on home retrofits and flood insurance as well as social information regarding the insurance purchase decisions of peers. Results indicate that the information intervention increased insurance purchases by about five percentage points, while no effect was detected for home retrofits. This effect is nearly equal to the increase in uptake that the national insurance program in Thailand has achieved through all other means since its establishment in 2012. If scaled up to include all uninsured, flood-prone households in Bangkok, nearly 70,000 additional households could be insured. The results suggest that well-designed information interventions could increase uptake of flood insurance, without additional premium subsidies or mandates.

  6. Group Selection as Behavioral Adaptation to Systematic Risk

    PubMed Central

    Zhang, Ruixun; Brennan, Thomas J.; Lo, Andrew W.

    2014-01-01

    Despite many compelling applications in economics, sociobiology, and evolutionary psychology, group selection is still one of the most hotly contested ideas in evolutionary biology. Here we propose a simple evolutionary model of behavior and show that what appears to be group selection may, in fact, simply be the consequence of natural selection occurring in stochastic environments with reproductive risks that are correlated across individuals. Those individuals with highly correlated risks will appear to form “groups”, even if their actions are, in fact, totally autonomous, mindless, and, prior to selection, uniformly randomly distributed in the population. This framework implies that a separate theory of group selection is not strictly necessary to explain observed phenomena such as altruism and cooperation. At the same time, it shows that the notion of group selection does captures a unique aspect of evolution—selection with correlated reproductive risk–that may be sufficiently widespread to warrant a separate term for the phenomenon. PMID:25353167

  7. Mechanical properties and corrosion behavior of Mg-HAP composites.

    PubMed

    Campo, R Del; Savoini, B; Muñoz, A; Monge, M A; Garcés, G

    2014-11-01

    Mg and Mg-HAP composites containing 5, 10 and 15 wt% of hydroxyapatite have been produced following a powder metallurgy route that consists of mixing raw powders and consolidation by extrusion. The microstructure, texture, mechanical behavior and resistance to corrosion under a PBS solution have been studied. Addition of HAP increases the microhardness of the composites, however the yield strength under compression slightly decreases. Texture analyses reveal a fiber texture for pure Mg that is weakened increasing the HAP fraction. This texture promotes twinning and softening of Mg and Mg-5HAP during the initial deformation stages. Mg-10HAP and Mg-15HAP present a strain-hardening dependence showing no softening. The volume fraction of HAP particles weakens the texture and favors the activation of secondary slip systems. Corrosion experiments in PBS solution have shown that Mg-5HAP exhibits the best resistance to corrosion. Texture and porosity appear to be the main material features controlling the corrosion rates of Mg-HAP composites under the present conditions.

  8. Dynamic Mechanical Behavior of Nickel-Aluminum Reinforced Epoxy Composites

    NASA Astrophysics Data System (ADS)

    Martin, Morgana; Hanagud, Sathyanaraya; Thadhani, Naresh

    2005-07-01

    Epoxy-based composites reinforced with a mixture of micron-sized Ni and micron or nano-sized Al powders were fabricated as bulk materials by cast/curing. The structural/mechanical behavior of these materials was evaluated using elastic and plastic property measurements via static and dynamic compression tests performed on rod shaped samples. Reverse Taylor anvil-on-rod impact tests combined with velocity interferometry gave qualitative and quantitative information about the transient deformation and failure response of the composites. The material containing 20wt% epoxy and nano-sized Al powder showed the most superior mechanical properties in terms of elastic modulus, and static and dynamic compressive strength, and strain before fracture, as compared to the other reinforced cast materials. The results illustrate that nano-sized Al particles provide significant enhancement to strength of epoxy composites by dispersing in the epoxy and generating a nano-Al containing epoxy matrix with embedded Ni particles. Funding for this research was provided by AFOSR/MURI Grant No. F49620-02-1-0382.

  9. Psychological Adaptation to Extreme Environments: Effects of Team Composition on Individual Adaptation

    NASA Technical Reports Server (NTRS)

    Wood, J.; Hysong, S. J.; Lugg, D. J.; Harm, D. L.

    1999-01-01

    This study is part of an ongoing program of research examining the psychological effects of isolation and confinement on individual adaptation, productivity and group relations in Antarctic winter personnel. This environment is used as an analogue for long-duration space mission scenarios, such as a space station sojourn, or a mission to Mars. Earlier results from this and other environments have demonstrated that: (1) most changes in psychological well-being are event-related and of relatively short duration; and (2) the greatest problem facing most individuals is interpersonal conflict. Content analysis of responses to open-ended questions has identified the numerous enjoyable aspects of Antarctic living, and confirmed that many of the problems reported were interpersonal in nature, and that problems varied significantly by station. Current work is exploring the effects of team assignment on the self-reported psychological changes and self-evaluations of members of isolated teams. This work includes identifying the dimensions by which subjects determine how well they are functioning. These dimensions (e.g., work, social life, internal emotional state) appear to play an important role in how subjects evaluate many aspects of life in isolation.

  10. The Role of Adaptive Behavior in Autism Spectrum Disorders: Implications for Functional Outcome

    ERIC Educational Resources Information Center

    Kanne, Stephen M.; Gerber, Andrew J.; Quirmbach, Linda M.; Sparrow, Sara S.; Cicchetti, Domenic V.; Saulnier, Celine A.

    2011-01-01

    The relationship between adaptive functioning and autism symptomatology was examined in 1,089 verbal youths with ASD examining results on Vineland-II, IQ, and measures of ASD severity. Strong positive relationships were found between Vineland subscales and IQ. Vineland Composite was negatively associated with age. IQ accounted a significant amount…

  11. Adaptation of community health worker-delivered behavioral activation for torture survivors in Kurdistan, Iraq

    PubMed Central

    Magidson, J. F.; Lejuez, C. W.; Kamal, T.; Blevins, E. J.; Murray, L. K.; Bass, J. K.; Bolton, P.; Pagoto, S.

    2016-01-01

    Background Growing evidence supports the use of Western therapies for the treatment of depression, trauma, and stress delivered by community health workers (CHWs) in conflict-affected, resource-limited countries. A recent randomized controlled trial (Bolton et al. 2014a) supported the efficacy of two CHW-delivered interventions, cognitive processing therapy (CPT) and brief behavioral activation treatment for depression (BATD), for reducing depressive symptoms and functional impairment among torture survivors in the Kurdish region of Iraq. Methods This study describes the adaptation of the CHW-delivered BATD approach delivered in this trial (Bolton et al.2014a), informed by the Assessment–Decision–Administration-Production–Topical experts–Integration–Training–Testing (ADAPT–ITT) framework for intervention adaptation (Wingood & DiClemente, 2008). Cultural modifications, adaptations for low-literacy, and tailored training and supervision for non-specialist CHWs are presented, along with two clinical case examples to illustrate delivery of the adapted intervention in this setting. Results Eleven CHWs, a study psychiatrist, and the CHW clinical supervisor were trained in BATD. The adaptation process followed the ADAPT–ITT framework and was iterative with significant input from the on-site supervisor and CHWs. Modifications were made to fit Kurdish culture, including culturally relevant analogies, use of stickers for behavior monitoring, cultural modifications to behavioral contracts, and including telephone-delivered sessions to enhance feasibility. Conclusions BATD was delivered by CHWs in a resource-poor, conflict-affected area in Kurdistan, Iraq, with some important modifications, including low-literacy adaptations, increased cultural relevancy of clinical materials, and tailored training and supervision for CHWs. Barriers to implementation, lessons learned, and recommendations for future efforts to adapt behavioral therapies for resource

  12. Investigating Filler Reinforcement and Nonlinear Viscoelastic Behavior in Polymer Composites

    NASA Astrophysics Data System (ADS)

    Zhu, Zhiyong; Wang, Shi-Qing; von Meerwall, Ernst

    2004-03-01

    Solid fillers have been known to enhance the linear viscoelastic responses of polymer melts and elastomers. Nonlinear viscoelastic behavior of such systems is closely related to the reinforcement of the linear viscoelascity. Understanding such phenomena as the Payne effect (where the storage modulus is measured to decrease in oscillatory shear with the amplitude of the oscillation and with time for a fixed amplitude) requires a better understanding of the filler reinforcement mechanism. Recent publications, from two different groups (a) (b) prompted our present study. Using monodisperse 1,4-polybutadiene melts as the matrix and nano-silicon oxide particles of 15 nm diameter as the fillers, we carried out a variety of viscoelastic and NMR-spin-echo diffusion measurements to elucidate the important role of the filler-filler networking in controlling the observed linear and nonlinear behavior at temperatures over 100 degrees above the glass transition temperature of PBD. (a)S.S. Sternstein and A. Zhu, Macromolecules 35, 7262 (2002); Composites Sci. and Techn. 63, 1113 (2003). This work claims that the reinforcement arises primarily from the entrapped chain entanglement due to chain adsorption on filler surfaces instead of the filler-filler networking. (b) H. Montes, F. Lequeux and J. Berriot, Macromolecules, 36, 8107 (2003). This work advocates that a glassy layer formed around each filler is responsible for the enhanced linear viscoelascity and for the observed nonlinear viscoelastic behavior such as the Payne effect.

  13. Associations between risk perception, spontaneous adaptation behavior to heat waves and heatstroke in Guangdong province, China

    PubMed Central

    2013-01-01

    Background In many parts of the world, including in China, extreme heat events or heat waves are likely to increase in intensity, frequency, and duration in light of climate change in the next decades. Risk perception and adaptation behaviors are two important components in reducing the health impacts of heat waves, but little is known about their relationships in China. This study aimed to examine the associations between risk perception to heat waves, adaptation behaviors, and heatstroke among the public in Guangdong province, China. Methods A total of 2,183 adult participants were selected using a four-stage sampling method in Guangdong province. From September to November of 2010 each subject was interviewed at home by a well-trained investigator using a structured questionnaire. The information collected included socio-demographic characteristics, risk perception and spontaneous adaptation behaviors during heat wave periods, and heatstroke experience in the last year. Chi-square tests and unconditional logistic regression models were employed to analyze the data. Results This study found that 14.8%, 65.3% and 19.9% of participants perceived heat waves as a low, moderate or high health risk, respectively. About 99.1% participants employed at least one spontaneous adaptation behavior, and 26.2%, 51.2% and 22.6% respondents employed <4, 4–7, and >7 adaptation behaviors during heat waves, respectively. Individuals with moderate (OR=2.93, 95% CI: 1.38-6.22) or high (OR=10.58, 95% CI: 4.74-23.63) risk perception experienced more heatstroke in the past year than others. Drinking more water and wearing light clothes in urban areas, while decreasing activity as well as wearing light clothes in rural areas were negatively associated with heatstroke. Individuals with high risk perception and employing <4 adaptation behaviors during heat waves had the highest risks of heatstroke (OR=47.46, 95% CI: 12.82-175.73). Conclusions There is a large room for improving health

  14. Evaluation of cervical marginal and internal adaptation using newer bulk fill composites: An in vitro study

    PubMed Central

    Agarwal, Rolly Shrivastav; Hiremath, Hemlatha; Agarwal, Jatin; Garg, Ashish

    2015-01-01

    Objective: To evaluate the cervical marginal and internal adaptation of posterior bulk fill resin composites of different viscosities, before and after thermo-cycling (TMC). Materials and Methods: Eighty box-only class II cavities were prepared in 40 extracted human premolars with the distal proximal box beneath the enamel-cementum junction (CEJ). The teeth in the experimental groups were restored with bulk fill resin composite restorations (Gr. I- Sonic Fill, Gr. II- SDR, Gr. III- Tetric N Ceram Bulk Fill or a conventional composite designed for 2-mm increments (Gr. IV- Tetric N Flow along with Tetric N Ceram). Before and after thermal cycling, the gap-free marginal length was analyzed using SEM of epoxy resin replicas. After thermal cycling, specimens were cut longitudinally in order to investigate internal dentine adaptation by epoxy replicas under SEM (500 × magnification). Results: Statistical analysis was performed using the ANOVA and Tukey Post Hoc tests (P < 0.05). In enamel, high percentages of gap-free margins were initially identified for all the groups, which declined after thermal cycling. However, no significant differences were identified among any of the groups (P > 0.05). In dentine, bulk fill groups performed at par with the incremental placement; for both marginal and internal adaptation (P < 0.05), for all materials except Tetric N Ceram Bulk Fill. Conclusions: Viscosity of the bulk fill restorative material influenced the proportion of gap-free marginal interface and the internal adaptation in dentin. PMID:25657529

  15. Compensatory Expressive Behavior for Facial Paralysis: Adaptation to Congenital or Acquired Disability

    PubMed Central

    Bogart, Kathleen R.; Tickle-Degnen, Linda; Ambady, Nalini

    2015-01-01

    Purpose/Objective Although there has been little research on the adaptive behavior of people with congenital compared to acquired disability, there is reason to predict that people with congenital conditions may be better adapted because they have lived with their conditions for their entire lives (Smart, 2008). We examined whether people with congenital facial paralysis (FP), compared to people with acquired FP, compensate more for impoverished facial expression by using alternative channels of expression (i.e. voice and body). Research Method/Design Participants with congenital (n = 13) and acquired (n = 14) FP were videotaped while recalling emotional events. Main Outcome Measures Expressive verbal behavior was measured using the Linguistic Inquiry Word Count (Pennebaker, Booth & Francis, 2007). Nonverbal behavior and FP severity were rated by trained coders. Results People with congenital FP, compared to acquired FP, used more compensatory expressive verbal and nonverbal behavior in their language, voices, and bodies. The extent of FP severity had little effect on compensatory expressivity. Conclusions/Implications This study provides the first behavioral evidence that people with congenital FP use more adaptations to express themselves than people with acquired FP. These behaviors could inform social functioning interventions for people with FP. PMID:22369116

  16. Cell Walls of Tobacco Cells and Changes in Composition Associated with Reduced Growth upon Adaptation to Water and Saline Stress 1

    PubMed Central

    Iraki, Naim M.; Singh, Narendra; Bressan, Ray A.; Carpita, Nicholas C.

    1989-01-01

    The relative mass of the cell walls of tobacco (Nicotiana tabacum L.) cells adapted to grow in medium containing 30% polyethylene glycol 8000 or 428 millimolar NaCl was reduced to about 50% of that of the walls of unadapted cells. Cellulose synthesis was inhibited substantially in adapted cells. The proportions of total pectin in walls of unadapted and adapted cells were about the same, but substantial amount of uronic acid-rich material from walls of cells adapted to either NaCl or polyethylene glycol was more easily extracted with cold sodium ethylenediamine tetraacetic acid solutions (NM Iraki et al. [1989] Plant Physiol. 91: 39-47). We examined the linkage composition of the pectic and hemicellulosic polysaccharides to ascertain chemical factors that may explain this difference in physical behavior. Adaptation to stress resulted in the formation of a loosely bound shell of polygalacturonic acid and rhamnogalacturonan. Pectins extracted from walls of adapted cells by either cold sodium ethylenediamine tetraacetic acid or hot ammonium oxalate were particularly enriched in rhamnose. Compared to pectins of unadapted cells, rhamnosyl units of the rhamnogalacturonans of adapted cells were more highly substituted with polymers containing arabinose and galactose, but the side groups were of greatly reduced molecular size. Possible functional roles of these modifications in cell wall metabolism related to adaptation to osmotic stress are discussed. PMID:16667041

  17. Dissociation of the behavioral and subjective components of nitrogen narcosis and diver adaptation.

    PubMed

    Hamilton, K; Laliberté, M F; Fowler, B

    1995-03-01

    We investigated adaptation to nitrogen narcosis by compressing 11 highly experienced divers in a hyperbaric chamber to the equivalent of 54.6 meters of seawater once a day for 5 consecutive days. The behavioral component of narcosis was assessed with a serial choice-reaction time (RT) task, and the subjective component with a global magnitude estimate. Supplementary magnitude estimates were obtained with adjectives describing work effectiveness and body sensations. The results showed that there was no adaptation on the RT task, although learning was evident. In contrast, the global estimate dissociated from RT and showed clear adaptation by Day 3. The work effectiveness adjectives followed RT and did not show adaptation. Some body sensation adjectives showed clear adaptation, but others did not. These results lead to the conclusion that the anecdotal reports of adaptation by divers can probably be attributed to the subjective rather than the behavioral component of narcosis. Dissociation of these components suggests mediation by different brain mechanisms, and it is speculated that the gamma-aminobutyric acidA/benzodiazepine receptor complex, which has been implicated in both the anesthetic and anxiolytic properties of agents such as nitrous oxide, may be involved.

  18. State Norms for IQ, Adaptive Behavior, and Sociocultural Status: Implications for Nonbiased Assessment.

    ERIC Educational Resources Information Center

    Reschly, Daniel J.; And Others

    Findings from the Iowa Assessment Project are examined regarding the assessment and use of information on adaptive behavior and sociocultural background in decisions about students with mild mental retardation. Background aspects reviewed include terminology regarding mild retardation; research, litigation, and legislation on the topic during the…

  19. A Systematic Review and Psychometric Evaluation of Adaptive Behavior Scales and Recommendations for Practice

    ERIC Educational Resources Information Center

    Floyd, Randy G.; Shands, Elizabeth I.; Alfonso, Vincent C.; Phillips, Jessica F.; Autry, Beth K.; Mosteller, Jessica A.; Skinner, Mary; Irby, Sarah

    2015-01-01

    Adaptive behavior scales are vital in assessing children and adolescents who experience a range of disabling conditions in school settings. This article presents the results of an evaluation of the design characteristics, norming, scale characteristics, reliability and validity evidence, and bias identification studies supporting 14…

  20. Intelligence, Parental Depression, and Behavior Adaptability in Deaf Children Being Considered for Cochlear Implantation

    ERIC Educational Resources Information Center

    Kushalnagar, Poorna; Krull, Kevin; Hannay, Julia; Mehta, Paras; Caudle, Susan; Oghalai, John

    2007-01-01

    Cognitive ability and behavioral adaptability are distinct, yet related, constructs that can impact childhood development. Both are often reduced in deaf children of hearing parents who do not provide sufficient language and communication access. Additionally, parental depression is commonly observed due to parent-child communication difficulties…

  1. Mothers' and Fathers' Parenting Styles and Associations with Toddlers' Externalizing, Internalizing, and Adaptive Behaviors

    ERIC Educational Resources Information Center

    Rinaldi, Christina M.; Howe, Nina

    2012-01-01

    The two primary objectives of the present study were to (a) investigate mothers' and fathers' reports of their own as well as their partner's parenting styles, and (b) assess how mothers' and fathers' parenting styles uniquely and jointly predicted toddlers' externalizing, internalizing, and adaptive behaviors. Fifty-nine mothers and fathers…

  2. Adaptive Interventions and SMART Designs: Application to Child Behavior Research in a Community Setting

    ERIC Educational Resources Information Center

    Kidwell, Kelley M.; Hyde, Luke W.

    2016-01-01

    Heterogeneity between and within people necessitates the need for sequential personalized interventions to optimize individual outcomes. Personalized or adaptive interventions (AIs) are relevant for diseases and maladaptive behavioral trajectories when one intervention is not curative and success of a subsequent intervention may depend on…

  3. Adaptive Responses to Prochloraz Exposure That Alter Dose-Response and Time-Course Behaviors

    EPA Science Inventory

    Dose response and time-course (DRTC) are, along with exposure, the major determinants of health risk. Adaptive changes within exposed organisms in response to environmental stress are common, and alter DRTC behaviors to minimize the effects caused by stressors. In this project, ...

  4. Using Mental Health Consultation to Decrease Disruptive Behaviors in Preschoolers: Adapting an Empirically-Supported Intervention

    ERIC Educational Resources Information Center

    Williford, Amanda P.; Shelton, Terri L.

    2008-01-01

    Background: This study examined the effectiveness of an adaptation of an empirically-supported intervention delivered using mental health consultation to preschoolers who displayed elevated disruptive behaviors. Method: Ninety-six preschoolers, their teachers, and their primary caregivers participated. Children in the intervention group received…

  5. Behavioral Adaptation in Deceptive Transactions: Fact or Fiction: Reply to Levine and McCornack.

    ERIC Educational Resources Information Center

    Buller, David B.; And Others

    1996-01-01

    Takes issue with the findings of T. Levine, and S. McCornack, which suggest that behavioral adaption explanation (BAE) cannot account for the probing effect, the effect that sources interrogatively probed appear more honest to message recipients than nonprobed sources. (TB)

  6. Longitudinal Changes in Adaptive Behavior in Adults with Down Syndrome: Interim Findings from a Longitudinal Study.

    ERIC Educational Resources Information Center

    Prasher, V. P.; Chung, Man Cheung; Haque, M. S.

    1998-01-01

    A study examined underlying factors for age-related decline in adaptive behavior in 128 adults with trisomy 21 over a three-year period. Presence of dementia was the only determining factor, although the difference in trend over time as compared to subjects without dementia was not significant. (Author/CR)

  7. Adaptive Behavior and Development of Infants and Toddlers with Williams Syndrome

    PubMed Central

    Kirchner, Rebecca M.; Martens, Marilee A.; Andridge, Rebecca R.

    2016-01-01

    Williams syndrome (WS) is a neurodevelopmental disorder that causes deficits in adaptive behavior, difficulties eating and sleeping, cognitive delays, and delayed development. Although researchers have conducted characterizations of children and adults with WS, less is known about young children with this disorder. This study characterizes the developmental and adaptive behavior features of 16 infants and toddlers with WS aged 3 months – 5 years. Data for this project was obtained from 2007 to 2014, and includes parent report data and standardized developmental testing. Thirty-one percent (31.3%) of parents reported that their infant/toddler with WS had sleeping problems and 58.3% reported feeding difficulties. Levels of adaptive behavior were in the Mildly Delayed range as measured by the Adaptive Behavior Assessment System, Second Edition. Self-care skills such as feeding or dressing oneself were significantly weaker than skills needed to function in the community, such as recognizing his/her home or throwing away trash. The difficulty with self-care skills is hypothesized to be related to the reported difficulties with eating and sleeping. Motor skills were significantly lower than both cognitive and language skills on the Bayley Scales of Infant and Toddler Development, Third Edition. The current study highlights the need for early intervention in these young children across all areas of development, particularly in self-care skills. PMID:27199832

  8. Future Time Perspective as a Predictor of Adolescents' Adaptive Behavior in School

    ERIC Educational Resources Information Center

    Carvalho, Renato Gil Gomes

    2015-01-01

    Future time perspective (FTP) has been associated with positive outcomes in adolescents' development across different contexts. However, the extent to which FTP influences adaptation needs additional understanding. In this study, we analysed the relationship between FTP and adolescents' behavior in school, as expressed in several indicators of…

  9. Rapid Assessment of the Effects of Restraint on Self-Injury and Adaptive Behavior.

    ERIC Educational Resources Information Center

    Wallace, Michele D.; Iwata, Brian A.; Zhou, Liming; Goff, Gerald A.

    1999-01-01

    This study evaluated the effects of restraint on occurrences of self-injurious behavior (SIB) and adaptive responses exhibited by two individuals with profound mental retardation across eight response-effort conditions with varying degrees of physical restraint. Analysis identified a restraint level for each individual that reduced SIB but did not…

  10. Neurodevelopmental Status and Adaptive Behaviors in Preschool Children with Chronic Kidney Disease

    ERIC Educational Resources Information Center

    Duquette, Peter J.; Hooper, Stephen R.; Icard, Phil F.; Hower, Sarah J.; Mamak, Eva G.; Wetherington, Crista E.; Gipson, Debbie S.

    2009-01-01

    This study examines the early neurodevelopmental function of infants and preschool children who have chronic kidney disease (CKD). Fifteen patients with CKD are compared to a healthy control group using the "Mullen Scales of Early Learning" (MSEL) and the "Vineland Adaptive Behavior Scale" (VABS). Multivariate analysis reveals…

  11. Longitudinal Changes in Adaptive Behaviors of Movers and Stayers: Findings from a Controlled Research Design

    ERIC Educational Resources Information Center

    Lerman, Paul; Apgar, Dawn Hall; Jordan,Tameeka

    2005-01-01

    Reviews of research on deinstitutionalization show that investigators have focused primarily on adaptive behavior changes of "movers," while paying minimal attention to "stayers." Analysis of their research also revealed some methodological problems. We assessed 150 movers and 150 stayers in 1994, before deinstitutionalization began in 1997. We…

  12. Effects of Culturally Adapted Parent Management Training on Latino Youth Behavioral Health Outcomes

    ERIC Educational Resources Information Center

    Martinez, Charles R.; Eddy, J. Mark

    2005-01-01

    A randomized experimental test of the implementation feasibility and the efficacy of a culturally adapted Parent Management Training intervention was conducted with a sample of 73 Spanish-speaking Latino parents with middle-school-aged youth at risk for problem behaviors. Intervention feasibility was evaluated through weekly parent satisfaction…

  13. Psychometric Properties of the Portuguese Version of the Adaptive Behavior Scale

    ERIC Educational Resources Information Center

    Santos, Sofia; Morato, Pedro; Luckasson, Ruth

    2014-01-01

    The adaptive behavior construct has gained prominent attention in human services over the last several years in Portugal, and its measurement has become an integral part of the assessment of populations with intellectual disability. In Portugal, diagnosis remains exclusively based on IQ measures, although some attention recently has been given to…

  14. A Post-Genomic View of Behavioral Development and Adaptation to the Environment

    ERIC Educational Resources Information Center

    LaFreniere, Peter; MacDonald, Kevin

    2013-01-01

    Recent advances in molecular genetics and epigenetics are reviewed that have major implications for the bio-behavioral sciences and for understanding how organisms adapt to their environments at both phylogenetic and ontogenic levels. From a post-genomics perspective, the environment is as crucial as the DNA sequence for constructing the…

  15. The Role of Metabotropic Glutamate Receptors and Cortical Adaptation in Habituation of Odor-Guided Behavior

    ERIC Educational Resources Information Center

    Yadon, Carly A.; Wilson, Donald A.

    2005-01-01

    Decreases in behavioral investigation of novel stimuli over time may be mediated by a variety of factors including changes in attention, internal state, and motivation. Sensory cortical adaptation, a decrease in sensory cortical responsiveness over prolonged stimulation, may also play a role. In olfaction, metabotropic glutamate receptors on…

  16. Studying the Genetics of Behavior and Evolution by Adaptation and Natural Selection.

    ERIC Educational Resources Information Center

    Silverman, Jules

    1998-01-01

    Provides an exercise designed to give students an appreciation for the genetic basis of behavior. Employs the phenomenon of glucose aversion as an example of evolution by mutation and accelerated natural selection, thereby revealing one of the ways in which organisms adapt to human interference. (DDR)

  17. The adaptive problems of female teenage refugees and their behavioral adjustment methods for coping

    PubMed Central

    Mhaidat, Fatin

    2016-01-01

    This study aimed at identifying the levels of adaptive problems among teenage female refugees in the government schools and explored the behavioral methods that were used to cope with the problems. The sample was composed of 220 Syrian female students (seventh to first secondary grades) enrolled at government schools within the Zarqa Directorate and who came to Jordan due to the war conditions in their home country. The study used the scale of adaptive problems that consists of four dimensions (depression, anger and hostility, low self-esteem, and feeling insecure) and a questionnaire of the behavioral adjustment methods for dealing with the problem of asylum. The results indicated that the Syrian teenage female refugees suffer a moderate degree of adaptation problems, and the positive adjustment methods they have used are more than the negatives. PMID:27175098

  18. High temperature fatigue behavior of tungsten copper composites

    NASA Technical Reports Server (NTRS)

    Verrilli, M. J.; Kim, Y.-S.; Gabb, T. P.

    1990-01-01

    The present study investigates the high-temperature fatigue behavior of a 9-v/o tungsten fiber-reinforced copper matrix composite. Load-controlled isothermal fatigue at 260 and 560 C and thermomechanical fatigue (TMF) experiments, both in-phase and out-of-phase between 260 and 560 C, were performed. The stress-strain response under all conditions displayed considerable inelasticity. Strain ratchetting was observed during all the fatigue experiments. For the isothermal fatigue and in-phase TMF tests, the ratchetting was always in a tensile direction, continuing until failure. The ratchetting during the out-of-phase TMF test shifted from a tensile to a compressive direction. For all cases, the fatigue lives were found to be controlled by the damage of the copper matrix. On a stress basis, TMF loading substantially reduced lives relative to isothermal cycling.

  19. Mechanical analysis of woven composites at high strain rates and its application to predicting impact behavior

    NASA Astrophysics Data System (ADS)

    Ryou, Hansun; Chung, Kwansoo; Lim, Ji-Ho

    2008-12-01

    The deformation behavior of woven composites at high strain rates was analyzed using a constitutive equation developed to describe the nonlinear, anisotropic/asymmetric and rate-dependent mechanical behavior of woven composites. The rate-dependent nonlinear behavior of woven composites was characterized at high strain rates (1 s-1 to 100 s-1) using a tensile testing method first proposed in this research. The material properties for the developed constitutive equation were determined and subsequently used in a finite element analysis of the deformation behavior of woven composites at high strain rates. Finally, the impact behavior of woven composites was predicted using the constitutive equation and the results were compared with experiments, showing that the current constitutive equation including the characterization method is adequate to describe the deformation behavior of woven composites at high strain rates up to impact level.

  20. Social stratification, classroom climate, and the behavioral adaptation of kindergarten children.

    PubMed

    Boyce, W Thomas; Obradovic, Jelena; Bush, Nicole R; Stamperdahl, Juliet; Kim, Young Shin; Adler, Nancy

    2012-10-16

    Socioeconomic status (SES) is the single most potent determinant of health within human populations, from infancy through old age. Although the social stratification of health is nearly universal, there is persistent uncertainty regarding the dimensions of SES that effect such inequalities and thus little clarity about the principles of intervention by which inequalities might be abated. Guided by animal models of hierarchical organization and the health correlates of subordination, this prospective study examined the partitioning of children's adaptive behavioral development by their positions within kindergarten classroom hierarchies. A sample of 338 5-y-old children was recruited from 29 Berkeley, California public school classrooms. A naturalistic observational measure of social position, parent-reported family SES, and child-reported classroom climate were used in estimating multilevel, random-effects models of children's adaptive behavior at the end of the kindergarten year. Children occupying subordinate positions had significantly more maladaptive behavioral outcomes than their dominant peers. Further, interaction terms revealed that low family SES and female sex magnified, and teachers' child-centered pedagogical practices diminished, the adverse influences of social subordination. Taken together, results suggest that, even within early childhood groups, social stratification is associated with a partitioning of adaptive behavioral outcomes and that the character of larger societal and school structures in which such groups are nested can moderate rank-behavior associations.

  1. Treating Individuals with Intellectual Disabilities and Challenging Behaviors with Adapted Dialectical Behavior Therapy

    ERIC Educational Resources Information Center

    Brown, Julie F.; Brown, Milton Z.; Dibiasio, Paige

    2013-01-01

    Approximately one third of adults with intellectual and developmental disabilities have emotion dysregulation and challenging behaviors (CBs). Although research has not yet confirmed that existing treatments adequately reduce CBs in this population, dialectical behavior therapy (DBT) holds promise, as it has been shown to effectively reduce CBs in…

  2. Laminate Analyses, Micromechanical Creep Response, and Fatigue Behavior of Polymer Matrix Composite Materials.

    DTIC Science & Technology

    1982-12-01

    FATIGUE BEHAVIOR of POLYMER MATRIX COMPOSITE MATERIALS , 4 " .’* .. . . ". ... .. ... . . ~December 1982 41 .. FINAL REPORT .Army Research Office I I...DEPARTMENT REPORT UWME-DR-201-108-1 LAMINATE ANALYSES, MICROMECHANICAL CREEP RESPONSE, AND FATIGUE BEHAVIOR OF POLYMER MATRIX COMPOSITE MATERIALS...Behavior of Polymer Matrix Composite 16 Sept. 1979 - 30 Nov. 1982 Materials 6 PERFORMING ORG. REPORT NUMBER UWME-DR-201-108-1 7. AUTHOR(.) S. CONTRACT

  3. Strength and failure behavior of stitched carbon/epoxy composites

    NASA Astrophysics Data System (ADS)

    Kamiya, Ryuta; Chou, Tsu-Wei

    2000-03-01

    This article presents a study of the effect of through-the-thickness stitching yarns upon the strength and failure behavior of multidirectionally reinforced composites. The in-plane yarns were placed in four directions (0,±45, 90) to form a quasi-isotropic preform, which had open spaces between adjacent yarns. These interyarn spaces allowed easy insertion of the through-the-thickness stitching yarns without significant damage of the in-plane fibers. Fiber volume fractions of over 54 pct were obtained by this method. The through-the-thickness yarn sizes used in this study were 2, 4, and 6 kilo-filament (kf). Non-stitched performs were also manufactured with the same fiber content and by the same procedure as the stiched preforms for the control experiments. All preforms were infiltrated with epoxy resin by the resin transfer molding (RTM) technique. In-plane tensile and compressive strength, interlaminar shear strength, and mode I fracture toughness of the carbon/epoxy composites were measured at three through-the-thickness yarn contents. Although the through-the-thickness yarns significantly enhanced the mode I fracture toughness, they tended to degrade the in-plane tensile and compressive strength. The failure process under interlaminar shear loading by double notch shear tests showed two distinct stages: the fiber-matrix interfacial failure followed by the breakage/debonding of the through-the-thickness yarns. The through-the-thickness yarns caused a reduction of the initial failure load in the first stage but could enhance the final failure load in the second stage. In composites with 6 kf through-the-thickness yarns, the final failure load could exceed the initial failure load. Scanning electron microscope (SEM) and optical microscopic examinations were also conducted for observing the failure mechanisms and fracture surfaces.

  4. High temperature fatigue behavior of tungsten copper composites

    NASA Technical Reports Server (NTRS)

    Verrilli, Michael J.; Kim, Yong-Suk; Gabb, Timothy P.

    1989-01-01

    The high temperature fatigue behavior of a 9 vol percent, tungsten fiber reinforced copper matrix composite was investigated. Load-controlled isothermal fatigue experiments at 260 and 560 C and thermomechanical fatigue (TMF) experiments, both in phase and out of phase between 260 and 560 C, were performed. The stress-strain response displayed considerable inelasticity under all conditions. Also, strain ratcheting was observed during all the fatigue experiments. For the isothermal fatigue and in-phase TMF tests, the ratcheting was always in a tensile direction, continuing until failure. The ratcheting during the out-of-phase TMF test shifted from a tensile direction to a compressive direction. This behavior was thought to be associated with the observed bulging and the extensive cracking of the out-of-phase specimen. For all cases, the fatigue lives were found to be controlled by damage to the copper matrix. Grain boundary cavitation was the dominant damage mechanism of the matrix. On a stress basis, TMF loading reduced lives substantially, relative to isothermal cycling. In-phase cycling resulted in the shortest lives, and isothermal fatigue at 260 C, the longest.

  5. Adaptive Behavior Ratings Correlate with Symptomatology and IQ among Individuals with High-Functioning Autism Spectrum Disorders

    ERIC Educational Resources Information Center

    Kenworthy, Lauren; Case, Laura; Harms, Madeline B.; Martin, Alex; Wallace, Gregory L.

    2010-01-01

    Caregiver report on the Adaptive Behavior Assessment System-II (ABAS) for 40 high-functioning individuals with Autism Spectrum Disorders (ASD) and 30 typically developing (TD) individuals matched for age, IQ, and sex ratio revealed global adaptive behavior deficits in ASD, with social skills impairments particularly prominent. Within the ASD…

  6. Health-related quality of life and adaptive behaviors of adolescents with sickle cell disease: stress processing moderators.

    PubMed

    Ziadni, Maisa S; Patterson, Chavis A; Pulgarón, Elizabeth R; Robinson, M Renée; Barakat, Lamia P

    2011-12-01

    The objective of this study was to examine resilience among adolescents with sickle cell disease (SCD), focusing on the interaction of health-related quality of life with stress processing to explain adaptive behavior. Forty-four adolescents with SCD completed paper-and-pencil measures of health-related quality of life, appraisals (hope), pain coping strategies (e.g. adherence), and adaptive behavior. Self-reported health-related quality of life was significantly associated with adaptive behavior, as was adherence. Findings for moderation were mixed. Pain coping strategies moderated the association of health-related quality of life with adaptive behavior such that at lower levels of Coping Strategies Questionnaire (CSQ) Adherence, better quality of life was associated with higher adaptive behavior. Similarly, at higher levels of hope, better quality of life was associated with higher adaptive behavior, and poorer quality of life was associated with lower adaptive behavior. Adolescents with SCD showed resilience, particularly in terms of personal adjustment, that may be explained by their appraisals and stress processing strategies. Interventions to support an optimistic or hopeful outlook and improve adherence to recommendations for medical management of sickle cell pain may result in improved resilience/adaptive behavior.

  7. Increasing Adaptive Behavior Skill Deficits from Childhood to Adolescence in Autism Spectrum Disorder: Role of Executive Function

    ERIC Educational Resources Information Center

    Pugliese, Cara E.; Anthony, Laura; Strang, John F.; Dudley, Katerina; Wallace, Gregory L.; Kenworthy, Lauren

    2015-01-01

    Almost half of all children with autism spectrum disorder have average cognitive abilities, yet outcome remains poor. Because outcome in HFASD is more related to adaptive behavior skills than cognitive level it is important to identify predictors of adaptive behavior. This study examines cognitive and demographic factors related to adaptive…

  8. Behaviorally Mediated, Warm Adaptation: A Physiological Strategy When Mice Are Allowed to Behaviorally Thermoregulate

    EPA Science Inventory

    Laboratory mice housed under standard vivarium conditions with an ambient temperature (Ta) of -22°C are likely to be cold stressed because this Ta is below their thermoneutral zone (TNZ). Mice raised at Tas within the TNZ adapt to the warmer temperatures, developing smaller int...

  9. Fabrication and Testing of Active and Adaptive Cyanate Ester Composite Mirrors

    NASA Technical Reports Server (NTRS)

    Bennett, H. E.

    2004-01-01

    The objective of the NASA/Bennett Optical Research Inc. (BOR) NAS8-02008 Phase II Program, which also incorporated ideas developed under the earlier NASA NAS8-01035 Phase 1 Program, was to develop a large mirror fabrication and test facility with emphasis on producing large, light weight active and adaptive optics. A principle objective was to develop mandrels on which to make large composite graphite-filled cyanate ester mirrors, Deliverables were two of these superpolished lightweight active/adaptive optic composite mirrors, one 12" (approx.1/3 meter) in diameter and one 22" (approx.1/2 meter) in diameter. In addition optical superpolishers for mandrels up to 1.2 meters in diameter, test instruments for determining optical figure and scattered light, novel design actuators for making the composite mirrors both active and adaptive, and passive and active means for measuring actuator performance were developed at BOR. We are now installing a superpolisher capable of producing 3 meter diameter mirror/mandrels. All polishers utilize the principle of centrifugal elutriation and produce superpolished mandrels with surface microroughnesses under 1 nm rms.

  10. Frontal theta links prediction errors to behavioral adaptation in reinforcement learning.

    PubMed

    Cavanagh, James F; Frank, Michael J; Klein, Theresa J; Allen, John J B

    2010-02-15

    Investigations into action monitoring have consistently detailed a frontocentral voltage deflection in the event-related potential (ERP) following the presentation of negatively valenced feedback, sometimes termed the feedback-related negativity (FRN). The FRN has been proposed to reflect a neural response to prediction errors during reinforcement learning, yet the single-trial relationship between neural activity and the quanta of expectation violation remains untested. Although ERP methods are not well suited to single-trial analyses, the FRN has been associated with theta band oscillatory perturbations in the medial prefrontal cortex. Mediofrontal theta oscillations have been previously associated with expectation violation and behavioral adaptation and are well suited to single-trial analysis. Here, we recorded EEG activity during a probabilistic reinforcement learning task and fit the performance data to an abstract computational model (Q-learning) for calculation of single-trial reward prediction errors. Single-trial theta oscillatory activities following feedback were investigated within the context of expectation (prediction error) and adaptation (subsequent reaction time change). Results indicate that interactive medial and lateral frontal theta activities reflect the degree of negative and positive reward prediction error in the service of behavioral adaptation. These different brain areas use prediction error calculations for different behavioral adaptations, with medial frontal theta reflecting the utilization of prediction errors for reaction time slowing (specifically following errors), but lateral frontal theta reflecting prediction errors leading to working memory-related reaction time speeding for the correct choice.

  11. A Self-Adaptive Behavior-Aware Recruitment Scheme for Participatory Sensing.

    PubMed

    Zeng, Yuanyuan; Li, Deshi

    2015-09-16

    Participatory sensing services utilizing the abundant social participants with sensor-enabled handheld smart device resources are gaining high interest nowadays. One of the challenges faced is the recruitment of participants by fully utilizing their daily activity behavior with self-adaptiveness toward the realistic application scenarios. In the paper, we propose a self-adaptive behavior-aware recruitment scheme for participatory sensing. People are assumed to join the sensing tasks along with their daily activity without pre-defined ground truth or any instructions. The scheme is proposed to model the tempo-spatial behavior and data quality rating to select participants for participatory sensing campaign. Based on this, the recruitment is formulated as a linear programming problem by considering tempo-spatial coverage, data quality, and budget. The scheme enables one to check and adjust the recruitment strategy adaptively according to application scenarios. The evaluations show that our scheme provides efficient sensing performance as stability, low-cost, tempo-spatial correlation and self-adaptiveness.

  12. Adaptive behavior of bacterial mechanosensitive channels is coupled to membrane mechanics.

    PubMed

    Belyy, Vladislav; Kamaraju, Kishore; Akitake, Bradley; Anishkin, Andriy; Sukharev, Sergei

    2010-06-01

    Mechanosensitive channel of small conductance (MscS), a tension-driven osmolyte release valve residing in the inner membrane of Escherichia coli, exhibits a complex adaptive behavior, whereas its functional counterpart, mechanosensitive channel of large conductance (MscL), was generally considered nonadaptive. In this study, we show that both channels exhibit similar adaptation in excised patches, a process that is completely separable from inactivation prominent only in MscS. When a membrane patch is held under constant pressure, adaptation of both channels is manifested as a reversible current decline. Their dose-response curves recorded with 1-10-s ramps of pressure are shifted toward higher tension relative to the curves measured with series of pulses, indicating decreased tension sensitivity. Prolonged exposure of excised patches to subthreshold tensions further shifts activation curves for both MscS and MscL toward higher tension with similar magnitude and time course. Whole spheroplast MscS recordings performed with simultaneous imaging reveal activation curves with a midpoint tension of 7.8 mN/m and the slope corresponding to approximately 15-nm(2) in-plane expansion. Inactivation was retained in whole spheroplast mode, but no adaptation was observed. Similarly, whole spheroplast recordings of MscL (V23T mutant) indicated no adaptation, which was present in excised patches. MscS activities tried in spheroplast-attached mode showed no adaptation when the spheroplasts were intact, but permeabilized spheroplasts showed delayed adaptation, suggesting that the presence of membrane breaks or edges causes adaptation. We interpret this in the framework of the mechanics of the bilayer couple linking adaptation of channels in excised patches to the relaxation of the inner leaflet that is not in contact with the glass pipette. Relaxation of one leaflet results in asymmetric redistribution of tension in the bilayer that is less favorable for channel opening.

  13. [Adaptation of vigilance behavior in ex situ conservation of Tibetan antelope].

    PubMed

    Sun, Ping; Yu, Hong-Hao; Zhao, Xin-Quan; Wang, De-Hua

    2011-10-01

    Tibetan antelope (Pantholops hodgsoni) are an endemic and endangered species of the Tibetan Plateau. Ex situ conservation may represent an important way to protect Tibetan antelope; however, this process may influence aspects of their behavior. To investigate the ability of these antelopes to adapt to new environments, a study on the vigilance behavior of captive antelope in different seasons was conducted. Using instantaneous scan sampling, focal animal sampling, and all-occurrence recording methods, the vigilance rate and vigilance time of captive male and female Tibetan antelope during cold and warm seasons were recorded and analyzed. Very significant sex differences in vigilance behavior were observed during the warm season, but were not observed in the cold season. Interestingly, vigilance behavior showed seasonal variation as there were significant differences in vigilance time and vigilance rate between cold and warm seasons in both males and females. Specifically, males and females showed more vigilance during the cold than warm season. No interaction between season and sex was found in the vigilance behavior of antelope. Comparing vigilance behavioral characteristic with the Kekexili Tibetan antelope indicated that captive antelope could adapt to a new environment.

  14. Fiber/matrix interface effect on monotonic and fatigue behavior of unidirectional carbon/epoxy composites

    SciTech Connect

    Large-Toumi, B.; Salvia, M.; Vincent, L.

    1996-12-31

    This paper deals with the study of the influence of fiber/matrix interface on the fatigue behavior of unidirectional carbon/epoxy composites. These materials are based on a T300/DGEBA/DDM system and the sizing nature, fiber oxidation, and degree of cure are varied independently. The interfacial properties were evaluated by the microdebonding test. The results show the good adhesion developed in the systems. The epoxy specific sizing increases the interfacial strength and the lack of oxidation treatment slightly decreases it. In three-point bending, the failures of the composites all appear on the compressive side, due to undesirable fiber kinking phenomena. To overcome these difficulties, which are linked to the compressive effects of the loading nose, a compression bending test was adapted to perform monotonic as well as fatigue tests. Under this configuration, progressive failure initiates on the tensile side and slowly propagates through the thickness of the sample. The Woehler`s curves can be plotted with moderate scattering. They are very flat, in comparison to the GFRP curves, and thus show the excellent fatigue behavior of these materials. The effect of the interface on both the monotonic and cyclic behaviors is clearly pointed out. The lack of fiber oxidation increases the monotonic properties without changing the fatigue resistance significantly. On the other hand, a slight matrix under-cure leads to a better intrinsic fatigue resistance but to smaller properties-to-failure. The analysis of both monotonic and cyclic properties reveals the existence of different optima depending on the interfacial properties.

  15. Neurocognitive, Social-Behavioral, and Adaptive Functioning in Preschool Children with Mild to Moderate Kidney Disease

    PubMed Central

    Hooper, Stephen R.; Gerson, Arlene C.; Johnson, Rebecca J.; Mendley, Susan R.; Shinnar, Shlomo; Lande, Marc B.; Matheson, Matthew B.; Gipson, Debbie S.; Morgenstern, Bruce; Warady, Bradley A.; Furth, Susan L.

    2016-01-01

    Objective The negative impact of End Stage Kidney Disease on cognitive function in children is well established, but no studies have examined the neurocognitive, social-behavioral, and adaptive behavior skills of preschool children with mild to moderate chronic kidney disease (CKD). Methods Participants included 124 preschool children with mild to moderate CKD, ages 12-68 months (median=3.7 years), and an associated mean glomerular filtration rate (GFR) of 50.0 ml/min per 1.73m2. In addition to level of function and percent of participants scoring≥1SD below the test mean, regression models examined the associations between biomarkers of CKD (GFR, anemia, hypertension, seizures, abnormal birth history), and Developmental Level/IQ, attention regulation, and parent ratings of executive functions, social-behavior, and adaptive behaviors. Results Median scores for all measures were in the average range; however, 27% were deemed at-risk for a Developmental Level/IQ<85, 20% were at-risk for attention variability, and parent ratings indicated 30% and 37% to be at-risk for executive dysfunction and adaptive behavior problems, respectively. Approximately 43% were deemed at-risk on two or more measures. None of the disease-related variables were significantly associated with these outcomes, although the presence of hypertension approached significance for attention variability (p<.09). Abnormal birth history and lower maternal education were significantly related to lower Developmental Level/IQ; seizures were related to lower parental ratings of executive function and adaptive behavior; and abnormal birth history was significantly related to lower ratings of adaptive behavior. When predicting risk status, the logistic regression did evidence both higher GFR and the lack of anemia to be associated with more intact Developmental Level/IQ. Conclusions These findings suggest relatively intact functioning for preschool children with mild to moderate CKD, but the need for ongoing

  16. Comparison of the marginal adaptation of direct and indirect composite inlay restorations with optical coherence tomography

    PubMed Central

    TÜRK, Ayşe Gözde; SABUNCU, Metin; ÜNAL, Sena; ÖNAL, Banu; ULUSOY, Mübin

    2016-01-01

    ABSTRACT Objective The purpose of the study was to use the photonic imaging modality of optical coherence tomography (OCT) to compare the marginal adaptation of composite inlays fabricated by direct and indirect techniques. Material and Methods Class II cavities were prepared on 34 extracted human molar teeth. The cavities were randomly divided into two groups according to the inlay fabrication technique. The first group was directly restored on cavities with a composite (Esthet X HD, Dentsply, Germany) after isolating. The second group was indirectly restored with the same composite material. Marginal adaptations were scanned before cementation with an invisible infrared light beam of OCT (Thorlabs), allowing measurement in 200 µm intervals. Restorations were cemented with a self-adhesive cement resin (SmartCem2, Dentsply), and then marginal adaptations were again measured with OCT. Mean values were statistically compared by using independent-samples t-test and paired samples t-test (p<0.05), before and after cementation. Results Direct inlays presented statistically smaller marginal discrepancy values than indirect inlays, before (p=0.00001442) and after (p=0.00001466) cementation. Marginal discrepancy values were increased for all restorations after cementation (p=0.00008839, p=0.000000952 for direct and indirect inlays, respectively). The mean marginal discrepancy value of the direct group increased from 56.88±20.04 µm to 91.88±31.7 µm, whereas the indirect group increased from 107.54±35.63 µm to 170.29±54.83 µm. Different techniques are available to detect marginal adaptation of restorations, but the OCT system can give quantitative information about resin cement thickness and its interaction between tooth and restoration in a nondestructive manner. Conclusions Direct inlays presented smaller marginal discrepancy than indirect inlays. The marginal discrepancy values were increased for all restorations that refer to cement thickness after cementation

  17. Fatigue and environmental behavior of long fiber thermoplastic (LFT) composites

    NASA Astrophysics Data System (ADS)

    Goel, Ashutosh

    In the present work we have characterized the mechanical behavior of long fiber thermoplastic (LFT) composites (21% E-glass fiber/polypropylene) under different conditions. We start by comparing the elastic modulus of LFT predicted by a microstructure-based approach called Object Oriented Finite (OOF) element method, and compare the result with prediction from various models commonly used in the literature and the experimental value. The predictions from the models used currently in the literature did not agree well with the experimental value due to the assumptions inherent in the models. The prediction by OOF was the closest to the experimental value because of the microstructure based approach which takes into account the fiber distribution and orientation during the finite element calculation. This was followed by characterization of fatigue behavior of LFT. Samples tested along longitudinal direction showed a higher fatigue life than the transverse samples because of the preferred orientation of the fibers along the longitudinal direction developed during the processing of LFT by extrusion-compression molding process. Fatigue life decreased with increase in frequency. Hysteretic energy loss and temperature rise were measured; they depended on the stress amplitude as well as the cyclic frequency. LFT composite showed a lower temperature rise compared to neat PP because LFT has higher thermal conductivity than neat PP and thus faster heat dissipation to the surroundings occur. The hysteretic heating also led to decrease in the modulus of LFT as a function of number of cycles. The last part of the work was to study the effect of ultraviolet (UV) exposure on the microstructure and mechanical properties of LFT. Microscopic observations revealed that the damage due to UV was confined only to the surface region in the form of surface cracking and exposure of fibers to the surface in the case of LFT. FTIR and nanoindentation results showed that there was a large

  18. Thermal Effects on the Bearing Behavior of Composite Joints

    NASA Technical Reports Server (NTRS)

    Walker, Sandra Polesky

    2001-01-01

    Thermal effects on the pin-bearing behavior of an IM7/PET15 composite laminate are studied comprehensively. A hypothesis presents factors influencing a change in pin-bearing strength with a change in temperature for a given joint design. The factors include the change in the state of residual cure stress, the material properties, and the fastener fit with a change in temperature. Experiments are conducted to determine necessary lamina and laminate material property data for the IM7/PET15 being utilized in this study. Lamina material properties are determined between the assumed stress free temperature of 460 F down to -200 F. Laminate strength properties are determined for several lay-ups at the operating temperatures of 350 F, 70 F, and -200 F. A three-dimensional finite element analysis model of a composite laminate subject to compressive loading is developed. Both the resin rich layer located between lamina and the thermal residual stresses present in the laminate due to curing are determined to influence the state of stress significantly. Pin-bearing tests of several lay-ups were conducted to develop an understanding on the effect of temperature changes on the pin-bearing behavior of the material. A computational study investigating the factors influencing pin-bearing strength was performed. A finite element model was developed and used to determine the residual thermal cure stresses in the laminate containing a hole. Very high interlaminar stress concentrations were observed two elements away from the hole boundary at all three operating temperatures. The pin-bearing problem was modeled assuming a rigid frictionless pin and restraining only radial displacements at the hole boundary. A uniform negative pressure load was then applied to the straight end of the model. A solution, where thermal residual stresses were combined with the state of stress due to pin-bearing loads was evaluated. The presence of thermal residual stresses intensified the interlaminar

  19. AgRP Neural Circuits Mediate Adaptive Behaviors in the Starved State

    PubMed Central

    Padilla, Stephanie L.; Qiu, Jian; Soden, Marta E.; Sanz, Elisenda; Nestor, Casey C; Barker, Forrest D.; Quintana, Albert; Zweifel, Larry S.; Rønnekleiv, Oline K.; Kelly, Martin J.; Palmiter, Richard D.

    2016-01-01

    In the face of starvation animals will engage in high-risk behaviors that would normally be considered maladaptive. Starving rodents for example will forage in areas that are more susceptible to predators and will also modulate aggressive behavior within a territory of limited or depleted nutrients. The neural basis of these adaptive behaviors likely involves circuits that link innate feeding, aggression, and fear. Hypothalamic AgRP neurons are critically important for driving feeding and project axons to brain regions implicated in aggression and fear. Using circuit-mapping techniques, we define a disynaptic network originating from a subset of AgRP neurons that project to the medial nucleus of the amygdala and then to the principle bed nucleus of the stria terminalis, which plays a role in suppressing territorial aggression and reducing contextual fear. We propose that AgRP neurons serve as a master switch capable of coordinating behavioral decisions relative to internal state and environmental cues. PMID:27019015

  20. Effect of light-curing method on marginal adaptation, microleakage, and microhardness of composite restorations.

    PubMed

    Ritter, André V; Cavalcante, Larissa M; Swift, Edward J; Thompson, Jeffrey Y; Pimenta, Luiz A

    2006-08-01

    The objective of this study was to investigate the effects of different light-curing methods on microleakage, marginal adaptation, and microhardness of composite restorations. Slot-type preparations were made in bovine teeth, with gingival margins on dentin. Specimens were divided into 12 groups (n = 12) according to composite-light-curing unit (LCU) combinations. Three composites were used: Filtek Supreme, Herculite XRV, and Heliomolar. All restorations were placed using the same adhesive. Four LCUs were used: a quartz-tungsten-halogen (QTH) LCU (Optilux 501), a first-generation light-emitting diode (LED) LCU (FreeLight 1), and two second-generation LED LCUs (FreeLight 2 and Translux Power Blue). After finishing and polishing, specimens were subjected to mechanical load cycling (100,000 cycles). Gingival margin adaptation was determined as a function of gap formation using epoxy replicas. Microleakage was evaluated by measuring dye penetration across the gingival wall in cross-sectioned specimens. Microhardness was measured as Knoop Hardness number (KHN) at different occluso-gingival locations in cross-sectioned specimens. Data were analyzed for statistical significance (p = 0.05) using appropriate statistical tests. Marginal adaptation was affected by load-cycling in most specimens, but no significant differences were observed among composites and LCUs. Microleakage was not affected by LCU, except for Heliomolar specimens which when cured with Optilux 501 resulted in higher microleakage scores than those obtained with the other LCUs. For microhardness, Translux Power Blue generally produced the highest values and the FreeLight 1 produced the lowest. The performance of the second-generation LED LCUs generally was similar to that of the QTH control, and better than that of the first-generation LED unit.

  1. Improving the reliability of autism diagnoses: examining the utility of adaptive behavior.

    PubMed

    Tomanik, Stacey S; Pearson, Deborah A; Loveland, Katherine A; Lane, David M; Bryant Shaw, J

    2007-05-01

    The classification agreement of the Autism Diagnostic Interview-Revised (ADI-R) and the Autism Diagnostic Observation Schedule (ADOS) was examined in 129 children and adolescents (aged 7-18 years) who were evaluated for autism. Participants received a diagnosis of autism or non-autism based on the ADI-R. Linear discriminant analysis revealed adequate concordance between the ADI-R and ADOS, with 75% of the participants being correctly classified using the ADOS. Classification accuracy significantly improved to 84% when a measure of adaptive functioning (i.e., the Vineland Adaptive Behavior Scales) was included in the analysis. The findings suggest that when clinicians obtain discrepant information on the ADI-R and ADOS, assessment of an individual's adaptive functioning may reduce diagnostic errors.

  2. Evaluation of the effect of vibration nonlinearity on convergence behavior of adaptive higher harmonic controllers

    NASA Technical Reports Server (NTRS)

    Molusis, J. A.; Mookerjee, P.; Bar-Shalom, Y.

    1983-01-01

    Effect of nonlinearity on convergence of the local linear and global linear adaptive controllers is evaluated. A nonlinear helicopter vibration model is selected for the evaluation which has sufficient nonlinearity, including multiple minimum, to assess the vibration reduction capability of the adaptive controllers. The adaptive control algorithms are based upon a linear transfer matrix assumption and the presence of nonlinearity has a significant effect on algorithm behavior. Simulation results are presented which demonstrate the importance of the caution property in the global linear controller. Caution is represented by a time varying rate weighting term in the local linear controller and this improves the algorithm convergence. Nonlinearity in some cases causes Kalman filter divergence. Two forms of the Kalman filter covariance equation are investigated.

  3. Evolutionary Influences of Plastic Behavioral Responses Upon Environmental Challenges in an Adaptive Radiation

    PubMed Central

    Foster, Susan A.; Wund, Matthew A.; Baker, John A.

    2015-01-01

    At the end of the 19th century, the suggestion was made by several scientists, including J. M. Baldwin, that behavioral responses to environmental change could both rescue populations from extinction (Baldwin Effect) and influence the course of subsequent evolution. Here we provide the historical and theoretical background for this argument and offer evidence of the importance of these ideas for understanding how animals (and other organisms that exhibit behavior) will respond to the rapid environmental changes caused by human activity. We offer examples from long-term research on the evolution of behavioral and other phenotypes in the adaptive radiation of the threespine stickleback fish (Gasterosteus aculeatus), a radiation in which it is possible to infer ancestral patterns of behavioral plasticity relative to the post-glacial freshwater radiation in northwestern North America, and to use patterns of parallelism and contemporary evolution to understand adaptive causes of responses to environmental modification. Our work offers insights into the complexity of cognitive responses to environmental change, and into the importance of examining multiple aspects of the phenotype simultaneously, if we are to understand how behavioral shifts contribute to the persistence of populations and to subsequent evolution. We conclude by discussing the origins of apparent novelties induced by environmental shifts, and the importance of accounting for geographic variation within species if we are to accurately anticipate the effects of anthropogenic environmental modification on the persistence and evolution of animals. PMID:26163679

  4. Evolutionary Influences of Plastic Behavioral Responses Upon Environmental Challenges in an Adaptive Radiation.

    PubMed

    Foster, Susan A; Wund, Matthew A; Baker, John A

    2015-09-01

    At the end of the 19th century, the suggestion was made by several scientists, including J. M. Baldwin, that behavioral responses to environmental change could both rescue populations from extinction (Baldwin Effect) and influence the course of subsequent evolution. Here we provide the historical and theoretical background for this argument and offer evidence of the importance of these ideas for understanding how animals (and other organisms that exhibit behavior) will respond to the rapid environmental changes caused by human activity. We offer examples from long-term research on the evolution of behavioral and other phenotypes in the adaptive radiation of the threespine stickleback fish (Gasterosteus aculeatus), a radiation in which it is possible to infer ancestral patterns of behavioral plasticity relative to the post-glacial freshwater radiation in northwestern North America, and to use patterns of parallelism and contemporary evolution to understand adaptive causes of responses to environmental modification. Our work offers insights into the complexity of cognitive responses to environmental change, and into the importance of examining multiple aspects of the phenotype simultaneously, if we are to understand how behavioral shifts contribute to the persistence of populations and to subsequent evolution. We conclude by discussing the origins of apparent novelties induced by environmental shifts, and the importance of accounting for geographic variation within species if we are to accurately anticipate the effects of anthropogenic environmental modification on the persistence and evolution of animals.

  5. The Influence of Cultural Adaptation and Sexual Risk Behaviors on Cervical Cytology in a Hispanic Population

    PubMed Central

    Ward, Kristy K.; Roncancio, Angelica M.; Breitkopf, Carmen Radecki

    2010-01-01

    OBJECTIVE To determine if the level of cultural adaptation (acculturation) of Hispanic women is associated with increased sexual risk behaviors and cervical cytological abnormalities. METHODS Hispanic women 18 to 55 years of age (mean = 30.5 ± 8.32) underwent routine Papanicoulaou (Pap) testing and completed a comprehensive survey (N=3149). Acculturation (cultural adaptation) was measured using the Short Acculturation Scale for Hispanics. Structural equation modeling (SEM) was employed to test a mediation model. RESULTS Highly acculturated women engaged in a greater number of sexual risk behaviors and were more likely to have an abnormal Pap test when compared to less acculturated Hispanic women (p < .001). CONCLUSION Acculturation is related to sexual risk taking and abnormal cervical cytology. Determination of acculturation level as part of culturally competent healthcare will aid in tailoring patient communication and counseling on the prevention of cervical cancer among Hispanic women. PMID:20864073

  6. Modeling the behavioral substrates of associate learning and memory - Adaptive neural models

    NASA Technical Reports Server (NTRS)

    Lee, Chuen-Chien

    1991-01-01

    Three adaptive single-neuron models based on neural analogies of behavior modification episodes are proposed, which attempt to bridge the gap between psychology and neurophysiology. The proposed models capture the predictive nature of Pavlovian conditioning, which is essential to the theory of adaptive/learning systems. The models learn to anticipate the occurrence of a conditioned response before the presence of a reinforcing stimulus when training is complete. Furthermore, each model can find the most nonredundant and earliest predictor of reinforcement. The behavior of the models accounts for several aspects of basic animal learning phenomena in Pavlovian conditioning beyond previous related models. Computer simulations show how well the models fit empirical data from various animal learning paradigms.

  7. The Association of Intelligence, Visual-Motor Functioning, and Personality Characteristics With Adaptive Behavior in Individuals With Williams Syndrome.

    PubMed

    Fu, Trista J; Lincoln, Alan J; Bellugi, Ursula; Searcy, Yvonne M

    2015-07-01

    Williams syndrome (WS) is associated with deficits in adaptive behavior and an uneven adaptive profile. This study investigated the association of intelligence, visual-motor functioning, and personality characteristics with the adaptive behavior in individuals with WS. One hundred individuals with WS and 25 individuals with developmental disabilities of other etiologies were included in this study. This study found that IQ and visual-motor functioning significantly predicted adaptive behavior in individuals of WS. Visual-motor functioning especially predicted the most amount of unique variance in overall adaptive behavior and contributed to the variance above and beyond that of IQ. Present study highlights the need for interventions that address visual-motor and motor functioning in individuals with WS.

  8. Neural adaptive control for vibration suppression in composite fin-tip of aircraft.

    PubMed

    Suresh, S; Kannan, N; Sundararajan, N; Saratchandran, P

    2008-06-01

    In this paper, we present a neural adaptive control scheme for active vibration suppression of a composite aircraft fin tip. The mathematical model of a composite aircraft fin tip is derived using the finite element approach. The finite element model is updated experimentally to reflect the natural frequencies and mode shapes very accurately. Piezo-electric actuators and sensors are placed at optimal locations such that the vibration suppression is a maximum. Model-reference direct adaptive neural network control scheme is proposed to force the vibration level within the minimum acceptable limit. In this scheme, Gaussian neural network with linear filters is used to approximate the inverse dynamics of the system and the parameters of the neural controller are estimated using Lyapunov based update law. In order to reduce the computational burden, which is critical for real-time applications, the number of hidden neurons is also estimated in the proposed scheme. The global asymptotic stability of the overall system is ensured using the principles of Lyapunov approach. Simulation studies are carried-out using sinusoidal force functions of varying frequency. Experimental results show that the proposed neural adaptive control scheme is capable of providing significant vibration suppression in the multiple bending modes of interest. The performance of the proposed scheme is better than the H(infinity) control scheme.

  9. Effect of curing unit and adhesive system on marginal adaptation of composite restorations.

    PubMed

    Casselli, Denise Sa Maia; Faria-e-Silva, Andre Luis; Casselli, Henrique; Martins, Luis Roberto Marcondes

    2012-01-01

    This study sought to evaluate how a curing unit and adhesive system affected the marginal adaptation of resin composite restorations. Class V cavities were prepared in bovine teeth with a gingival margin in dentin and an incisal margin in enamel. The cavities were restored with a micro-hybrid resin composite using one of four adhesives: Single Bond 2, Prime & Bond NT, Clearfil SE Bond, Xeno IV. The light-activations were performed using a quartz-tungsten-halogen (QTH) lamp or a second-generation light-emitting diode (LED). Restorations were finished and polished and epoxy replicas were prepared. Marginal adaptation was analyzed by using scanning electronic microscopy (magnification 500X). The widest gaps in each margin were recorded, and data were submitted to Kruskal-Wallis, Mann-Whitney, and Wilcoxon tests (α = 0.05). Differences between the adhesives were observed only when the dentin margins were evaluated: Clearfil SE Bond demonstrated better marginal adaptation than Prime & Bond NT or Single Bond 2 (which demonstrated the widest gaps in the dentin margin). The type of curing unit only affected the results for Xeno IV when the enamel margin was analyzed; the LED lamp promoted smaller gaps than the QTH lamp.

  10. Mechanical Behavior of Homogeneous and Composite Random Fiber Networks

    NASA Astrophysics Data System (ADS)

    Shahsavari, Ali

    systems with large multiscale heterogeneity, which controls their mechanical behavior. This pronounced heterogeneity leads to a pronounced size and boundary condition effects on their mechanical behavior. To emphasize the source of the size effect, the network heterogeneity is characterized by analyzing the geometry of the network (density distribution), the strain field and the strain energy distribution. It is shown that the heterogeneity of the mechanical fields depends not only on the network topology, but also on the ratio between the bending and axial stiffness of fibers. In this study, the size effect is quantified and the minimum model size needed to eliminate the size effect for a given set of system parameters, is determined. The results are also used for the selection of the size of representative volume elements useful for multiscale models of fiber networks such as the sequential approach. The elastic response of composite random fiber networks in which two types of fibers are used, is studied. This analysis is performed by adding stiff fibers to a relatively softer base while considering two cases: cross-linked and non-cross-linked added fibers. The linear elastic modulus of the network is determined in terms of the system parameters, including the density of added fibers. The results are compared to the case of adding stiff fibers to a homogeneous continuum base. It is shown that there is a threshold of added fiber density, above which the axial stiffens of the base filaments controls the mechanics. In this regime, the elastic response of the composites that have network bases mimics the behavior of those with continuum bases. The results presented in this thesis are relevant for many biological and engineering fibrous materials, including connective tissue, the cellular cytoskeleton, special clothing, consumer products, filters, and dampers. It is shown that the overall behavior of the material is very sensitive to several system parameters (power law

  11. Behavior of Frame-Stiffened Composite Panels with Damage

    NASA Technical Reports Server (NTRS)

    Jegley, Dawn C.

    2013-01-01

    NASA, the Air Force Research Laboratory and The Boeing Company have worked to develop new low-cost, light-weight composite structures for aircraft. A Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS) concept has been developed which offers advantages over traditional metallic structures. In this concept, a stitched carbon-epoxy material system has been developed with the potential for reducing the weight and cost of transport aircraft structure by eliminating fasteners, thereby reducing part count and labor. Stitching and the use of thin skins with rod-stiffeners to move loading away from the morevulnerable outer surface produces a structurally efficient, damage tolerant design. This study focuses on the behavior of PRSEUS panels loaded in the frame direction and subjected to severe damage in the form of a severed central frame in a three-frame panel. Experimental results for a pristine two-frame panel and analytical predictions for pristine two-frame and three-frame panels as well as damaged three-frame panels are described.

  12. Adaptation.

    PubMed

    Broom, Donald M

    2006-01-01

    The term adaptation is used in biology in three different ways. It may refer to changes which occur at the cell and organ level, or at the individual level, or at the level of gene action and evolutionary processes. Adaptation by cells, especially nerve cells helps in: communication within the body, the distinguishing of stimuli, the avoidance of overload and the conservation of energy. The time course and complexity of these mechanisms varies. Adaptive characters of organisms, including adaptive behaviours, increase fitness so this adaptation is evolutionary. The major part of this paper concerns adaptation by individuals and its relationships to welfare. In complex animals, feed forward control is widely used. Individuals predict problems and adapt by acting before the environmental effect is substantial. Much of adaptation involves brain control and animals have a set of needs, located in the brain and acting largely via motivational mechanisms, to regulate life. Needs may be for resources but are also for actions and stimuli which are part of the mechanism which has evolved to obtain the resources. Hence pigs do not just need food but need to be able to carry out actions like rooting in earth or manipulating materials which are part of foraging behaviour. The welfare of an individual is its state as regards its attempts to cope with its environment. This state includes various adaptive mechanisms including feelings and those which cope with disease. The part of welfare which is concerned with coping with pathology is health. Disease, which implies some significant effect of pathology, always results in poor welfare. Welfare varies over a range from very good, when adaptation is effective and there are feelings of pleasure or contentment, to very poor. A key point concerning the concept of individual adaptation in relation to welfare is that welfare may be good or poor while adaptation is occurring. Some adaptation is very easy and energetically cheap and

  13. Compositional, mechanical and hydrologic controls on fault slip behavior

    NASA Astrophysics Data System (ADS)

    Ikari, Matt J.

    comparing the frictional behavior of granular gouge and lithified fault rock as an analogue for cataclastic fault rocks at seismogenic depths, the lithification of fault rock is found to have a significant strengthening effect, however in phyllosilicate-rich rocks pre-existing foliation provides a weakening mechanism that offsets the strengthening due to lithification. This weakening depends on the intensity of foliation such that strongly foliated rocks, such as books of mica sheets, are significantly weaker than granular mica gouges. Very thick fault zones can exhibit a reduction in measured apparent friction, the magnitude of which may be related to the orientation of through-going R1 shears and internal structural complexity. Consistent velocity-strengthening behavior is observed for both lithified and granular phyllosilicate-rich samples despite the observation of slip localization features in microstructural analysis, suggesting that as an isolated parameter advanced lithification state of fault rock is also inadequate for allowing seismic slip nucleation. Collectively, the results of the experiments in this study have several important implications for fault slip behavior. Granular, unconsolidated phyllosilicate-rich gouges, such as those that are common at shallow depths in both subduction zones and strike-slip faults, will tend to be aseismic, a condition that may be related to their overall weakness. The transition from aseismic to seismic slip at the updip limit of the seismogenic zone should be driven by changes in pressure and temperature, due to the overall ambient conditions as well as inducing changes in the character of the fault material itself. These may include compositional changes and mechanical effects of the lithification process, such as consolidation and cementation. However, when tested as isolated variables, the dehydration of smectite, conversion of smectite to illite, and lithification of fault gouge were found to be insufficient in allowing

  14. Depth of cure and marginal adaptation to dentin of xenon lamp polymerized resin composites.

    PubMed

    Hasegawa, T; Itoh, K; Yukitani, W; Wakumoto, S; Hisamitsu, H

    2001-01-01

    Marginal adaptation of four resin composites (Clearfil APX, Estelite, Silux Plus and Z-100) cured with two xenon lamp units (Plasma Arc Curing System or Apollo 95E) or a halogen lamp unit (Witelite) were evaluated by measuring the wall-to-wall contraction gap width. A cylindrical dentin cavity (ø3 mm x 1.5 mm) prepared in an extracted human molar was treated with the Megabond system or an experimental bonding system consisting of 0.5 M EDTA, 35% GM and Clearfil Photo Bond prior to composite filling and was irradiated for three seconds (xenon lamp) or 40 seconds (halogen lamp). The contraction gap was measured with a light microscope. In addition, the curing capability of these three light sources was evaluated by measuring the curing depth of the composites filled in a split Teflon mold (ø4 mm x 8 mm). There was no marginal gap formation for Clearfil APX, Estelite and Silux Plus treated with the experimental bonding system regardless of the type of light sources. The curing depth of the xenon lamp was significantly higher than the halogen lamp, while marginal adaptation did not suffer any significant deterioration.

  15. Toward a mechanics of adaptive behavior: evolutionary dynamics and matching theory statics.

    PubMed

    McDowell, J J; Popa, Andrei

    2010-09-01

    One theory of behavior dynamics instantiates the idea that behavior evolves in response to selection pressure from the environment in the form of reinforcement. This computational theory implements Darwinian principles of selection, reproduction, and mutation, which operate on a population of potential behaviors by means of a genetic algorithm. The behavior of virtual organisms animated by this theory may be studied in any experimental environment. The evolutionary theory was tested by comparing the steady-state behavior it generated on concurrent schedules to the description of steady state behavior provided by modern matching theory. Ensemble fits of modern matching theory that enforced its constant-k requirement and the parametric identities required by its equations, accounted for large proportions of data variance, left random residuals, and yielded parameter estimates with values and properties similar to those obtained in experiments with live organisms. These results indicate that the dynamics of the evolutionary theory and the statics of modern matching theory together constitute a good candidate for a mechanics of adaptive behavior.

  16. Toward a Mechanics of Adaptive Behavior: Evolutionary Dynamics and Matching Theory Statics

    PubMed Central

    McDowell, J.J; Popa, Andrei

    2010-01-01

    One theory of behavior dynamics instantiates the idea that behavior evolves in response to selection pressure from the environment in the form of reinforcement. This computational theory implements Darwinian principles of selection, reproduction, and mutation, which operate on a population of potential behaviors by means of a genetic algorithm. The behavior of virtual organisms animated by this theory may be studied in any experimental environment. The evolutionary theory was tested by comparing the steady-state behavior it generated on concurrent schedules to the description of steady state behavior provided by modern matching theory. Ensemble fits of modern matching theory that enforced its constant-k requirement and the parametric identities required by its equations, accounted for large proportions of data variance, left random residuals, and yielded parameter estimates with values and properties similar to those obtained in experiments with live organisms. These results indicate that the dynamics of the evolutionary theory and the statics of modern matching theory together constitute a good candidate for a mechanics of adaptive behavior. PMID:21451751

  17. Adolescents misperceive and are influenced by high-status peers' health risk, deviant, and adaptive behavior.

    PubMed

    Helms, Sarah W; Choukas-Bradley, Sophia; Widman, Laura; Giletta, Matteo; Cohen, Geoffrey L; Prinstein, Mitchell J

    2014-12-01

    Most peer influence research examines socialization between adolescents and their best friends. Yet, adolescents also are influenced by popular peers, perhaps due to misperceptions of social norms. This research examined the extent to which out-group and in-group adolescents misperceive the frequencies of peers' deviant, health risk, and adaptive behaviors in different reputation-based peer crowds (Study 1) and the prospective associations between perceptions of high-status peers' and adolescents' own substance use over 2.5 years (Study 2). Study 1 examined 235 adolescents' reported deviant (vandalism, theft), health risk (substance use, sexual risk), and adaptive (exercise, studying) behavior, and their perceptions of jocks', populars', burnouts', and brains' engagement in the same behaviors. Peer nominations identified adolescents in each peer crowd. Jocks and populars were rated as higher status than brains and burnouts. Results indicated that peer crowd stereotypes are caricatures. Misperceptions of high-status crowds were dramatic, but for many behaviors, no differences between populars'/jocks' and others' actual reported behaviors were revealed. Study 2 assessed 166 adolescents' substance use and their perceptions of popular peers' (i.e., peers high in peer perceived popularity) substance use. Parallel process latent growth analyses revealed that higher perceptions of popular peers' substance use in Grade 9 (intercept) significantly predicted steeper increases in adolescents' own substance use from Grade 9 to 11 (slope). Results from both studies, utilizing different methods, offer evidence to suggest that adolescents misperceive high-status peers' risk behaviors, and these misperceptions may predict adolescents' own risk behavior engagement.

  18. Adolescents Misperceive and Are Influenced By High Status Peers' Health Risk, Deviant, and Adaptive Behavior

    PubMed Central

    Helms, Sarah W.; Choukas-Bradley, Sophia; Widman, Laura; Giletta, Matteo; Cohen, Geoffrey L.; Prinstein, Mitchell J.

    2015-01-01

    Most peer influence research examines socialization between adolescents and their best friends. Yet, adolescents also are influenced by popular peers, perhaps due to misperceptions of social norms. This research examined the extent to which out-group and in-group adolescents misperceive the frequencies of peers' deviant, health risk, and adaptive behaviors in different reputation-based peer crowds (Study 1) and the prospective associations between perceptions of high status peers' and adolescents' own substance use over 2.5 years (Study 2). Study 1 examined 235 adolescents' reported deviant (vandalism, theft), health risk (substance use, sexual risk), and adaptive (exercise, studying) behavior, and their perceptions of Jocks', Populars', Burnouts', and Brains' engagement in the same behaviors. Peer nominations identified adolescents in each peer crowd. Jocks and Populars were rated as higher status than Brains and Burnouts. Results indicated that peer crowd stereotypes are caricatures. Misperceptions of high status crowds were dramatic, but for many behaviors, no differences between Populars'/Jocks' and others' actual reported behaviors were revealed. Study 2 assessed 166 adolescents' substance use and their perceptions of popular peers' (i.e., peers high in peer perceived popularity) substance use. Parallel process latent growth analyses revealed that higher perceptions of popular peers' substance use in Grade 9 (intercept) significantly predicted steeper increases in adolescents' own substance use from Grade 9 to 11 (slope). Results from both studies, utilizing different methods, offer evidence to suggest that adolescents misperceive high status peers' risk behaviors, and these misperceptions may predict adolescents' own risk behavior engagement. PMID:25365121

  19. Synaptic plasticity in a recurrent neural network for versatile and adaptive behaviors of a walking robot.

    PubMed

    Grinke, Eduard; Tetzlaff, Christian; Wörgötter, Florentin; Manoonpong, Poramate

    2015-01-01

    Walking animals, like insects, with little neural computing can effectively perform complex behaviors. For example, they can walk around their environment, escape from corners/deadlocks, and avoid or climb over obstacles. While performing all these behaviors, they can also adapt their movements to deal with an unknown situation. As a consequence, they successfully navigate through their complex environment. The versatile and adaptive abilities are the result of an integration of several ingredients embedded in their sensorimotor loop. Biological studies reveal that the ingredients include neural dynamics, plasticity, sensory feedback, and biomechanics. Generating such versatile and adaptive behaviors for a many degrees-of-freedom (DOFs) walking robot is a challenging task. Thus, in this study, we present a bio-inspired approach to solve this task. Specifically, the approach combines neural mechanisms with plasticity, exteroceptive sensory feedback, and biomechanics. The neural mechanisms consist of adaptive neural sensory processing and modular neural locomotion control. The sensory processing is based on a small recurrent neural network consisting of two fully connected neurons. Online correlation-based learning with synaptic scaling is applied to adequately change the connections of the network. By doing so, we can effectively exploit neural dynamics (i.e., hysteresis effects and single attractors) in the network to generate different turning angles with short-term memory for a walking robot. The turning information is transmitted as descending steering signals to the neural locomotion control which translates the signals into motor actions. As a result, the robot can walk around and adapt its turning angle for avoiding obstacles in different situations. The adaptation also enables the robot to effectively escape from sharp corners or deadlocks. Using backbone joint control embedded in the the locomotion control allows the robot to climb over small obstacles

  20. Synaptic plasticity in a recurrent neural network for versatile and adaptive behaviors of a walking robot

    PubMed Central

    Grinke, Eduard; Tetzlaff, Christian; Wörgötter, Florentin; Manoonpong, Poramate

    2015-01-01

    Walking animals, like insects, with little neural computing can effectively perform complex behaviors. For example, they can walk around their environment, escape from corners/deadlocks, and avoid or climb over obstacles. While performing all these behaviors, they can also adapt their movements to deal with an unknown situation. As a consequence, they successfully navigate through their complex environment. The versatile and adaptive abilities are the result of an integration of several ingredients embedded in their sensorimotor loop. Biological studies reveal that the ingredients include neural dynamics, plasticity, sensory feedback, and biomechanics. Generating such versatile and adaptive behaviors for a many degrees-of-freedom (DOFs) walking robot is a challenging task. Thus, in this study, we present a bio-inspired approach to solve this task. Specifically, the approach combines neural mechanisms with plasticity, exteroceptive sensory feedback, and biomechanics. The neural mechanisms consist of adaptive neural sensory processing and modular neural locomotion control. The sensory processing is based on a small recurrent neural network consisting of two fully connected neurons. Online correlation-based learning with synaptic scaling is applied to adequately change the connections of the network. By doing so, we can effectively exploit neural dynamics (i.e., hysteresis effects and single attractors) in the network to generate different turning angles with short-term memory for a walking robot. The turning information is transmitted as descending steering signals to the neural locomotion control which translates the signals into motor actions. As a result, the robot can walk around and adapt its turning angle for avoiding obstacles in different situations. The adaptation also enables the robot to effectively escape from sharp corners or deadlocks. Using backbone joint control embedded in the the locomotion control allows the robot to climb over small obstacles

  1. Marginal adaptation of class V composite restorations submitted to thermal and mechanical cycling

    PubMed Central

    CASSELLI, Denise Sá Maia; FARIA-E-SILVA, André Luis; CASSELLI, Henrique; MARTINS, Luis Roberto Marcondes

    2013-01-01

    Objective: This study evaluated the effect of the margin location and an adhesive system on the marginal adaptation of composite restorations. Material and Methods: Class V cavities were prepared in bovine teeth with the gingival margin on the dentin and the incisal margin on the enamel. The cavities were restored with a micro-hybrid composite resin using an etch-and-rinse [Single Bond 2 (SB)] or a self-etching adhesive [Clearfil SE Bond (CL)]. After finishing and polishing the restorations, epoxy replicas were prepared. The marginal adaptation was analyzed using scanning electronic microscopy (SEM, 500 x magnification). The higher gap width in each margin was recorded (T0). After the first evaluation, the samples were submitted to thermal cycling (2,000 cycles of 5ºC±2ºC followed by 55ºC±2ºC - T1) and mechanical cycling (100,000 cycles of 50 kN and 2 Hz - T2). Replicas of samples were rebuilt after each cycling and analyzed under SEM. The data were submitted to Mann-Whitney, Wilcoxon and Friedman testing (a=0.05). Results: The SB presented higher gaps in the dentin than the enamel, while there was no difference between the substrate for the CL. In the dentin, the CL showed better marginal sealing than the SB. The opposite occurred in the enamel. There were no significant differences between the baseline, thermal and mechanical cycling for any experimental condition. Conclusions: The outcomes of the present study showed that the adhesive system and margin location have an important effect on the marginal adaptation of composite restorations. PMID:23559115

  2. Changes in cortical activity associated with adaptive behavior during repeated balance perturbation of unpredictable timing

    PubMed Central

    Mierau, Andreas; Hülsdünker, Thorben; Strüder, Heiko K.

    2015-01-01

    The compensation for a sudden balance perturbation, unpracticed and unpredictable in timing and magnitude is accompanied by pronounced postural instability that is suggested to be causal to falls. However, subsequent presentations of an identical perturbation are characterized by a marked decrease of the amplitude of postural reactions; a phenomenon called adaptation or habituation. This study aimed to identify cortical characteristics associated with adaptive behavior during repetitive balance perturbations based on single-trial analyses of the P1 and N1 perturbation-evoked potentials. Thirty-seven young men were exposed to ten transient balance perturbations while balancing on the dominant leg. Thirty two-channel electroencephalography (EEG), surface electromyography (EMG) of the ankle plantar flexor muscles and postural sway (i.e., Euclidean distance of the supporting platform) were recorded simultaneously. The P1 and N1 potentials were localized and the amplitude/latency was analyzed trial by trial. The best match sources for P1 and N1 potentials were located in the parietal (Brodmann area (BA) 5) and midline fronto-central cortex (BA 6), respectively. The amplitude and latency of the P1 potential remained unchanged over trials. In contrast, a significant adaptation of the N1 amplitude was observed. Similar adaptation effects were found with regard to postural sway and ankle plantarflexors EMG activity of the non-dominant (free) leg; i.e., an indicator for reduced muscular co-contraction and/or less temporary bipedal stance to regain stability. Significant but weak correlations were found between N1 amplitude and postural sway as well as EMG activity. These results highlight the important role of the midline fronto-central cortex for adaptive behavior associated with balance control. PMID:26528154

  3. Changes in cortical activity associated with adaptive behavior during repeated balance perturbation of unpredictable timing.

    PubMed

    Mierau, Andreas; Hülsdünker, Thorben; Strüder, Heiko K

    2015-01-01

    The compensation for a sudden balance perturbation, unpracticed and unpredictable in timing and magnitude is accompanied by pronounced postural instability that is suggested to be causal to falls. However, subsequent presentations of an identical perturbation are characterized by a marked decrease of the amplitude of postural reactions; a phenomenon called adaptation or habituation. This study aimed to identify cortical characteristics associated with adaptive behavior during repetitive balance perturbations based on single-trial analyses of the P1 and N1 perturbation-evoked potentials. Thirty-seven young men were exposed to ten transient balance perturbations while balancing on the dominant leg. Thirty two-channel electroencephalography (EEG), surface electromyography (EMG) of the ankle plantar flexor muscles and postural sway (i.e., Euclidean distance of the supporting platform) were recorded simultaneously. The P1 and N1 potentials were localized and the amplitude/latency was analyzed trial by trial. The best match sources for P1 and N1 potentials were located in the parietal (Brodmann area (BA) 5) and midline fronto-central cortex (BA 6), respectively. The amplitude and latency of the P1 potential remained unchanged over trials. In contrast, a significant adaptation of the N1 amplitude was observed. Similar adaptation effects were found with regard to postural sway and ankle plantarflexors EMG activity of the non-dominant (free) leg; i.e., an indicator for reduced muscular co-contraction and/or less temporary bipedal stance to regain stability. Significant but weak correlations were found between N1 amplitude and postural sway as well as EMG activity. These results highlight the important role of the midline fronto-central cortex for adaptive behavior associated with balance control.

  4. Adapting Dialectical Behavior Therapy for the Treatment of Dissociative Identity Disorder.

    PubMed

    Foote, Brad; Van Orden, Kim

    2016-12-31

    Dialectical Behavior Therapy (DBT), created by Marsha Linehan, has been shown to be an effective therapy for the treatment of borderline personality disorder (BPD) and for suicidal and self-harming behavior. Dissociative identity disorder (DID) is a complex post-traumatic disorder which is highly comorbid with BPD, shares a number of clinical features with BPD, and which like BPD features a high degree of suicidality. The DID treatment literature emphasizes the importance of a staged approach, beginning with the creation of a safe therapeutic frame prior to addressing traumatic material; DBT is also a staged treatment, in which behavioral and safety issues are addressed in Stage 1, and trauma work reserved for Stage 2. The authors describe adapting DBT, and especially its techniques for Stage 1 safety work, for work with DID patients. Basic theoretical principles are described and illustrated with a case example.

  5. The Adolescent Behavioral Activation Program: Adapting Behavioral Activation as a Treatment for Depression in Adolescence.

    PubMed

    McCauley, Elizabeth; Gudmundsen, Gretchen; Schloredt, Kelly; Martell, Christopher; Rhew, Isaac; Hubley, Samuel; Dimidjian, Sona

    2016-01-01

    This study aimed to examine implementation feasibility and initial treatment outcomes of a behavioral activation (BA) based treatment for adolescent depression, the Adolescent Behavioral Activation Program (A-BAP). A randomized, controlled trial was conducted with 60 clinically referred adolescents with a depressive disorder who were randomized to receive either 14 sessions of A-BAP or uncontrolled evidenced-based practice for depression. The urban sample was 64% female, predominantly Non-Hispanic White (67%), and had an average age of 14.9 years. Measures of depression, global functioning, activation, and avoidance were obtained through clinical interviews and/or through parent and adolescent self-report at preintervention and end of intervention. Intent-to-treat linear mixed effects modeling and logistic regression analysis revealed that both conditions produced statistically significant improvement from pretreatment to end of treatment in depression, global functioning, and activation and avoidance. There were no significant differences across treatment conditions. These findings provide the first step in establishing the efficacy of BA as a treatment for adolescent depression and support the need for ongoing research on BA as a way to enhance the strategies available for treatment of depression in this population.

  6. Fracture behavior of thick, laminated graphite/epoxy composites

    NASA Technical Reports Server (NTRS)

    Harris, C. E.; Morris, D. H.

    1984-01-01

    The effect of laminate thickness on the fracture behavior of laminated graphite epoxy (T300/5208) composites was studied. The predominantly experimental research program included the study of the 0/+ or - 45/90 sub ns and 0/90 sub ns laminates with thickness of 8, 32, 64, 96 and 120 plies and the 0/+ or - 45 sub ns laminate with thickness of 6, 30, 60, 90 and 120 plies. The research concentrated on the measurement of fracture toughness utilizing the center-cracked tension, compact tension and three point bend specimen configurations. The development of subcritical damage at the crack tip was studied nondestructively using enhanced X-ray radiography and destructively using the laminate deply technique. The test results showed fracture toughness to be a function of laminate thickness. The fracture toughness of the 0 + or - 45/90 sub ns and 0/90 sub ns laminates decreased with increasing thickness and asymptotically approached lower bound values of 30 ksi square root of in. (1043 MPa square root of mm and 25 ksi square root of in (869 MPa square root of mm respectively. In contrast to the other two laminates, the fracture toughness of the 0/+ or - 45 sub ns laminate increased sharply with increasing thickness but reached an upper plateau value of 40 ksi square root of in (1390 MPa square root of mm) at 30 plies. Fracture toughness was independent of crack size for both thin and thick laminates for all three laminate types except for the 0/90 sub 2s laminate which spilt extensively. The center cracked tension, three point bend and compact tension specimens gave comparable results.

  7. Iron Supplementation in Infancy Contributes to More Adaptive Behavior at 10 Years of Age1234

    PubMed Central

    Lozoff, Betsy; Castillo, Marcela; Clark, Katy M.; Smith, Julia B.; Sturza, Julie

    2014-01-01

    Most studies of behavioral/developmental effects of iron deficiency anemia (IDA) or iron supplementation in infancy have found social-emotional differences. Differences could relate to behavioral inhibition or lack of positive affect and altered response to reward. To determine long-term behavioral effects, the study was a follow-up of a randomized controlled trial of behavioral/developmental effects of preventing IDA in infancy. Healthy Chilean infants free of IDA at age 6 mo were randomly assigned to iron supplementation or no added iron (formula with iron/powdered cow milk, vitamins with/without iron) from ages 6 to 12 mo. At age 10 y, 59% (666 of 1123) and 68% (366 of 534) of iron-supplemented and no-added-iron groups were assessed. Social-emotional outcomes included maternal-reported behavior problems, self-reported behavior, examiner ratings, and video coding of a social stress task and gamelike paradigms. Examiners rated the iron-supplemented group as more cooperative, confident, persistent after failure, coordinated, and direct and reality-oriented in speech and working harder after praise compared with the no-added-iron group. In a task designed to elicit positive affect, supplemented children spent more time laughing and smiling together with their mothers and started smiling more quickly. In the social stress task they smiled and laughed more and needed less prompting to complete the task. All P values were <0.05; effect sizes were 0.14–0.36. There were no differences in behaviors related to behavioral inhibition, such as anxiety/depression or social problems. In sum, iron supplementation in infancy was associated with more adaptive behavior at age 10 y, especially in affect and response to reward, which may improve performance at school and work, mental health, and personal relationships. PMID:24717366

  8. Changes and roles of membrane compositions in the adaptation of Saccharomyces cerevisiae to ethanol.

    PubMed

    Wang, Yanfeng; Zhang, Shuxian; Liu, Huaqing; Zhang, Lei; Yi, Chenfeng; Li, Hao

    2015-12-01

    Bioethanol fermentation by Saccharomyces cerevisiae is often stressed by the accumulation of ethanol. Cell membrane is the first assaulting target of ethanol. Ethanol-adapted S. cerevisiae strains provide opportunity to shed light on membrane functions in the ethanol tolerance. This study aimed at clarifying the roles of cell membrane in the ethanol tolerance of S. cerevisiae through comparing membrane components between S. cerevisiae parental strain and ethanol-adapted strains. A directed evolutionary engineering was performed to obtain the ethanol-adapted S. cerevisiae strains. The parental, ethanol-adapted M5 and M10 strains were selected to be compared the percentage of viable cells after exposing to ethanol stress and cell membrane compositions (i.e., ergosterol, trehalose, and fatty acids). Compared with the parental strain, M5 or M10 strain had higher survival rate in the presence of 10% v/v ethanol. Compared with that in the parental strain, contents of trehalose, ergosterol, and fatty acids increased about 15.7, 12.1, and 29.3%, respectively, in M5 strain, and about 47.5, 107.8, and 61.5%, respectively, in M10 strain. Moreover, expression differences of genes involved in fatty acids metabolisms among the parental, M5 and M10 strains were analyzed by quantitative real-time polymerase chain reaction (qRT-PCR), and results demonstrated that M5 or M10 strain had higher expression of ACC1 and OLE1 than the parental strain. These results indicated that although being exposed to step-wise increased ethanol, S. cerevisiae cells might remodel membrane components or structure to adapt to the ethanol stress.

  9. Fractal behavior of traffic volume on urban expressway through adaptive fractal analysis

    NASA Astrophysics Data System (ADS)

    He, Hong-di; Wang, Jun-li; Wei, Hai-rui; Ye, Cheng; Ding, Yi

    2016-02-01

    In this paper, we investigate the fractal behavior of traffic volume in urban expressway based on a newly developed adaptive fractal analysis (AFA), which has a number of advantages over traditional method of detrended fluctuation analysis (DFA). Before fractal analysis, autocorrelation function was first adopted on traffic volume data and the long-range correlation behavior was found to be existed in both on-ramp and off-ramp situations. Then AFA as well as DFA was applied to further examine the fractal behavior. The results showed that the multifractality and the long-range anti-persistent behavior existed on both on-ramp and off-ramp. Additionally, multifractal analysis on weekdays and weekends are performed respectively and the results show that the degree of multifractality on weekdays is higher than that on weekends, implying that long-range correlation behaviors were more obvious on weekdays. Finally, the source of multifractality is examined with randomly shuffled and the surrogated series. Long-range correlation behaviors are identified in both on-ramp and off-ramp situations and fat-tail distributions were found to make little in the contributions of multifractality.

  10. Anomalous brain functional connectivity contributing to poor adaptive behavior in Down syndrome.

    PubMed

    Pujol, Jesus; del Hoyo, Laura; Blanco-Hinojo, Laura; de Sola, Susana; Macià, Dídac; Martínez-Vilavella, Gerard; Amor, Marta; Deus, Joan; Rodríguez, Joan; Farré, Magí; Dierssen, Mara; de la Torre, Rafael

    2015-03-01

    Research in Down syndrome has substantially progressed in the understanding of the effect of gene overexpression at the molecular level, but there is a paucity of information on the ultimate consequences on overall brain functional organization. We have assessed the brain functional status in Down syndrome using functional connectivity MRI. Resting-state whole-brain connectivity degree maps were generated in 20 Down syndrome individuals and 20 control subjects to identify sites showing anomalous synchrony with other areas. A subsequent region-of-interest mapping served to detail the anomalies and to assess their potential contribution to poor adaptive behavior. Down syndrome individuals showed higher regional connectivity in a ventral brain system involving the amygdala/anterior temporal region and the ventral aspect of both the anterior cingulate and frontal cortices. By contrast, lower functional connectivity was identified in dorsal executive networks involving dorsal prefrontal and anterior cingulate cortices and posterior insula. Both functional connectivity increases and decreases contributed to account for patient scoring on adaptive behavior related to communication skills. The data overall suggest a distinctive functional organization with system-specific anomalies associated with reduced adaptive efficiency. Opposite effects were identified on distinct frontal and anterior temporal structures and relative sparing of posterior brain areas, which is generally consistent with Down syndrome cognitive profile. Relevantly, measurable connectivity changes, as a marker of the brain functional anomaly, could have a role in the development of therapeutic strategies addressed to improve the quality of life in Down syndrome individuals.

  11. International adoption: assessment of adaptive and maladaptive behavior of adopted minors in Spain.

    PubMed

    Barcons-Castel, Natalia; Fornieles-Deu, Albert; Costas-Moragas, Carme

    2011-05-01

    Research on adjustment of internationally adopted children indicates that, although they have adequate development, more emotional and behavioral problems are detected compared with nonadopted children. In this research, emotional and behavioral characteristics of a sample of 52 internationally adopted minors were examined with the BASC (Parent Rating Scales and Self-Report of Personality), comparing the outcomes with 44 nonadopted minors, all of them of ages between 6 and 11 years (mean age = 8.01 years). Results indicate differences between adopted and nonadopted children related to somatization, adopted minors are those that obtain lower scores in the scale, and in the adaptability scale, where nonadopted minors obtain higher scores. Significant differences were found in the adaptive abilities scales, suggesting that nonadopted boys show better abilities than adopted ones, and no differences were found among girls. In general, boys present higher scores in externalizing symptomatology and depression than girls. Among adopted children, time spent in an institution is a variable that has negative impact on the onset of externalizing and internalizing problems. Minors coming from Eastern Europe display more attentional problems, poorer adaptive abilities and poorer interpersonal relations than the rest of the minors. According to the age at placement, attentional problems appear in minors adopted after the age of 3 years.

  12. Sensory processing, school performance, and adaptive behavior of young school-age children with fetal alcohol spectrum disorders.

    PubMed

    Jirikowic, Tracy; Olson, Heather Carmichael; Kartin, Deborah

    2008-05-01

    This study described sensory processing behaviors and sensory-motor abilities in children with fetal alcohol spectrum disorders (FASD) and explored their relationship to home and school function. A clinic-referred sample of 25 children with FASD, ages 5 to 8 years, was compared with 26 children with typical development, balanced for age, gender, and race/ethnicity, on standardized tests examining sensory processing, sensory-motor performance, school performance, and adaptive behavior. Children with FASD scored significantly more poorly on sensory processing, sensory-motor, adaptive, and academic achievement measures, and demonstrated more problem behaviors at home and school. Correlations were significant between measures of sensory processing and sensory-motor performance, adaptive behavior, and some aspects of academic performance. Sensory processing and related foundational sensory-motor impairments should be considered when determining the developmental needs of children with FASD. These impairments may co-occur with and contribute, at least in part, to decreased adaptive and school function.

  13. Creep behavior of tungsten/niobium and tungsten/niobium-1 percent zirconium composites

    NASA Technical Reports Server (NTRS)

    Petrasek, Donald W.; Titran, Robert H.

    1988-01-01

    The creep behavior and microstructural stability of tungsten fiber reinforced niobium and niobium 1 percent zirconium was determined at 1400 and 1500 K in order to assess the potential of this material for use in advanced space power systems. The creep behavior of the composite materials could be described by a power law creep equation. A linear relationship was found to exist between the minimum creep rate of the composite and the inverse of the composite creep rupture life. The composite materials had an order of magnitude increase in stress to achieve 1 percent creep strain and in rupture strength at test temperatures of 1400 and 1500 K compared to unreinforced material. The composite materials were also stronger than the unreinforced materials by an order of magnitude when density was taken into consideration. Results obtained on the creep behavior and microstructural stability of the composites show significant potential improvement in high temperature properties and mass reduction for space power system components.

  14. Human Behavior & Low Energy Architecture: Linking Environmental Adaptation, Personal Comfort, & Energy Use in the Built Environment

    NASA Astrophysics Data System (ADS)

    Langevin, Jared

    Truly sustainable buildings serve to enrich the daily sensory experience of their human inhabitants while consuming the least amount of energy possible; yet, building occupants and their environmentally adaptive behaviors remain a poorly characterized variable in even the most "green" building design and operation approaches. This deficiency has been linked to gaps between predicted and actual energy use, as well as to eventual problems with occupant discomfort, productivity losses, and health issues. Going forward, better tools are needed for considering the human-building interaction as a key part of energy efficiency strategies that promote good Indoor Environmental Quality (IEQ) in buildings. This dissertation presents the development and implementation of a Human and Building Interaction Toolkit (HABIT), a framework for the integrated simulation of office occupants' thermally adaptive behaviors, IEQ, and building energy use as part of sustainable building design and operation. Development of HABIT begins with an effort to devise more reliable methods for predicting individual occupants' thermal comfort, considered the driving force behind the behaviors of focus for this project. A long-term field study of thermal comfort and behavior is then presented, and the data it generates are used to develop and validate an agent-based behavior simulation model. Key aspects of the agent-based behavior model are described, and its predictive abilities are shown to compare favorably to those of multiple other behavior modeling options. Finally, the agent-based behavior model is linked with whole building energy simulation in EnergyPlus, forming the full HABIT program. The program is used to evaluate the energy and IEQ impacts of several occupant behavior scenarios in the simulation of a case study office building for the Philadelphia climate. Results indicate that more efficient local heating/cooling options may be paired with wider set point ranges to yield up to 24

  15. Implementation of CAPIO for Composite Adaptive Control of Cross-Coupled Unstable Aircraft

    NASA Technical Reports Server (NTRS)

    Yildiz, Yildiray; Kolmanovsky, Ilya V.

    2011-01-01

    This paper presents an implementation of a recently developed control allocation algorithm CAPIO (a Control Allocation technique to recover from Pilot Induced Oscillations) for composite adaptive control of an inertially cross coupled unstable aircraft. When actuators are rate-saturated due to either an aggressive pilot command, high gain of the flight control system or some anomaly in the system, the effective delay in the control loop may increase due to the phase shifting between the desired and the achieved system states. This effective time delay may deteriorate the performance or even destabilize the system in some cases, depending on the severity of rate saturation. CAPIO reduces the effective time delay by minimizing the phase shift between the commanded and the actual attitude accelerations. We present simulation results for an unstable aircraft with cross-coupling controlled with a composite adaptive controller in the presence of rate saturation. The simulations demonstrate the potential of CAPIO serving as an effective rate saturation compensator in adverse conditions.

  16. Computational simulation of intermingled-fiber hybrid composite behavior

    NASA Technical Reports Server (NTRS)

    Mital, Subodh K.; Chamis, Christos C.

    1992-01-01

    Three-dimensional finite-element analysis and a micromechanics based computer code ICAN (Integrated Composite Analyzer) are used to predict the composite properties and microstresses of a unidirectional graphite/epoxy primary composite with varying percentages of S-glass fibers used as hydridizing fibers at a total fiber volume of 0.54. The three-dimensional finite-element model used in the analyses consists of a group of nine fibers, all unidirectional, in a three-by-three unit cell array. There is generally good agreement between the composite properties and microstresses obtained from both methods. The results indicate that the finite-element methods and the micromechanics equations embedded in the ICAN computer code can be used to obtain the properties of intermingled fiber hybrid composites needed for the analysis/design of hybrid composite structures. However, the finite-element model should be big enough to be able to simulate the conditions assumed in the micromechanics equations.

  17. Modeling the Stress Strain Behavior of Woven Ceramic Matrix Composites

    NASA Technical Reports Server (NTRS)

    Morscher, Gregory N.

    2006-01-01

    Woven SiC fiber reinforced SiC matrix composites represent one of the most mature composite systems to date. Future components fabricated out of these woven ceramic matrix composites are expected to vary in shape, curvature, architecture, and thickness. The design of future components using woven ceramic matrix composites necessitates a modeling approach that can account for these variations which are physically controlled by local constituent contents and architecture. Research over the years supported primarily by NASA Glenn Research Center has led to the development of simple mechanistic-based models that can describe the entire stress-strain curve for composite systems fabricated with chemical vapor infiltrated matrices and melt-infiltrated matrices for a wide range of constituent content and architecture. Several examples will be presented that demonstrate the approach to modeling which incorporates a thorough understanding of the stress-dependent matrix cracking properties of the composite system.

  18. Crystallization behavior and glass formation of selected lunar compositions.

    NASA Technical Reports Server (NTRS)

    Scherer, G.; Hopper, R. W.; Uhlmann, D. R.

    1972-01-01

    The kinetics of crystal growth have been determined over a wide range of temperature, from 800 to 1219 C, for lunar compositions 14259 and 14310. At all temperatures for both compositions the extent of crystal growth is found to be a linear function of time. For both materials, the growth rate versus temperature relations exhibit the form generally found with glass-forming materials. At all temperatures measured, the crystal growth rate of composition 14259 is smaller than that of composition 14310. The maximum growth rate for both compositions occurs at a temperature of about 1120 C. The growth rate data are combined with viscosity data obtained on the same compositions to construct the reduced growth rate versus undercooling relations.

  19. Treatment Sequencing for Childhood ADHD: A Multiple-Randomization Study of Adaptive Medication and Behavioral Interventions.

    PubMed

    Pelham, William E; Fabiano, Gregory A; Waxmonsky, James G; Greiner, Andrew R; Gnagy, Elizabeth M; Pelham, William E; Coxe, Stefany; Verley, Jessica; Bhatia, Ira; Hart, Katie; Karch, Kathryn; Konijnendijk, Evelien; Tresco, Katy; Nahum-Shani, Inbal; Murphy, Susan A

    2016-01-01

    Behavioral and pharmacological treatments for children with attention deficit/hyperactivity disorder (ADHD) were evaluated to address whether endpoint outcomes are better depending on which treatment is initiated first and, in case of insufficient response to initial treatment, whether increasing dose of initial treatment or adding the other treatment modality is superior. Children with ADHD (ages 5-12, N = 146, 76% male) were treated for 1 school year. Children were randomized to initiate treatment with low doses of either (a) behavioral parent training (8 group sessions) and brief teacher consultation to establish a Daily Report Card or (b) extended-release methylphenidate (equivalent to .15 mg/kg/dose bid). After 8 weeks or at later monthly intervals as necessary, insufficient responders were rerandomized to secondary interventions that either increased the dose/intensity of the initial treatment or added the other treatment modality, with adaptive adjustments monthly as needed to these secondary treatments. The group beginning with behavioral treatment displayed significantly lower rates of observed classroom rule violations (the primary outcome) at study endpoint and tended to have fewer out-of-class disciplinary events. Further, adding medication secondary to initial behavior modification resulted in better outcomes on the primary outcomes and parent/teacher ratings of oppositional behavior than adding behavior modification to initial medication. Normalization rates on teacher and parent ratings were generally high. Parents who began treatment with behavioral parent training had substantially better attendance than those assigned to receive training following medication. Beginning treatment with behavioral intervention produced better outcomes overall than beginning treatment with medication.

  20. Effects of Risperidone and Parent Training on Adaptive Functioning in Children with Pervasive Developmental Disorders and Serious Behavioral Problems

    ERIC Educational Resources Information Center

    Scahill, Lawrence; McDougle, Christopher J.; Aman, Michael G.; Johnson, Cynthia; Handen, Benjamin; Bearss, Karen; Dziura, James; Butter, Eric; Swiezy, Naomi G.; Arnold, L. Eugene; Stigler, Kimberly A.; Sukhodolsky, Denis D.; Lecavalier, Luc; Pozdol, Stacie L.; Nikolov, Roumen; Hollway, Jill A.; Korzekwa, Patricia; Gavaletz, Allison; Kohn, Arlene E.; Koenig, Kathleen; Grinnon, Stacie; Mulick, James A.; Yu, Sunkyung; Vitiello, Benedetto

    2012-01-01

    Objective: Children with Pervasive Developmental Disorders (PDDs) have social interaction deficits, delayed communication, and repetitive behaviors as well as impairments in adaptive functioning. Many children actually show a decline in adaptive skills compared with age mates over time. Method: This 24-week, three-site, controlled clinical trial…

  1. Being Mindful about the Assessment of Culture: A Cultural Analysis of Culturally Adapted Acceptance-Based Behavior Therapy Approaches

    ERIC Educational Resources Information Center

    La Roche, Martin; Lustig, Kara

    2013-01-01

    In this article we review a wide range of cultural adaptations of acceptance-based behavior therapies (ABBT) from a cultural perspective. Consistent with the cultural match model, we argue that psychotherapeutic cultural adaptations are more effective as the cultural characteristics of patients are matched to the cultural characteristics of the…

  2. Hard tissue as a composite material. I - Bounds on the elastic behavior.

    NASA Technical Reports Server (NTRS)

    Katz, J. L.

    1971-01-01

    Recent determination of the elastic moduli of hydroxyapatite by ultrasonic methods permits a re-examination of the Voigt or parallel model of the elastic behavior of bone, as a two phase composite material. It is shown that such a model alone cannot be used to describe the behavior of bone. Correlative data on the elastic moduli of dentin, enamel and various bone samples indicate the existence of a nonlinear dependence of elastic moduli on composition of hard tissue. Several composite models are used to calculate the bounds on the elastic behavior of these tissues. The limitations of these models are described, and experiments to obtain additional critical data are discussed.

  3. Criticality as a Set-Point for Adaptive Behavior in Neuromorphic Hardware

    PubMed Central

    Srinivasa, Narayan; Stepp, Nigel D.; Cruz-Albrecht, Jose

    2015-01-01

    Neuromorphic hardware are designed by drawing inspiration from biology to overcome limitations of current computer architectures while forging the development of a new class of autonomous systems that can exhibit adaptive behaviors. Several designs in the recent past are capable of emulating large scale networks but avoid complexity in network dynamics by minimizing the number of dynamic variables that are supported and tunable in hardware. We believe that this is due to the lack of a clear understanding of how to design self-tuning complex systems. It has been widely demonstrated that criticality appears to be the default state of the brain and manifests in the form of spontaneous scale-invariant cascades of neural activity. Experiment, theory and recent models have shown that neuronal networks at criticality demonstrate optimal information transfer, learning and information processing capabilities that affect behavior. In this perspective article, we argue that understanding how large scale neuromorphic electronics can be designed to enable emergent adaptive behavior will require an understanding of how networks emulated by such hardware can self-tune local parameters to maintain criticality as a set-point. We believe that such capability will enable the design of truly scalable intelligent systems using neuromorphic hardware that embrace complexity in network dynamics rather than avoiding it. PMID:26648839

  4. Clark's Nutcrackers (Nucifraga columbiana) Flexibly Adapt Caching Behavior to a Cooperative Context.

    PubMed

    Clary, Dawson; Kelly, Debbie M

    2016-01-01

    Corvids recognize when their caches are at risk of being stolen by others and have developed strategies to protect these caches from pilferage. For instance, Clark's nutcrackers will suppress the number of caches they make if being observed by a potential thief. However, cache protection has most often been studied using competitive contexts, so it is unclear whether corvids can adjust their caching in beneficial ways to accommodate non-competitive situations. Therefore, we examined whether Clark's nutcrackers, a non-social corvid, would flexibly adapt their caching behaviors to a cooperative context. To do so, birds were given a caching task during which caches made by one individual were reciprocally exchanged for the caches of a partner bird over repeated trials. In this scenario, if caching behaviors can be flexibly deployed, then the birds should recognize the cooperative nature of the task and maintain or increase caching levels over time. However, if cache protection strategies are applied independent of social context and simply in response to cache theft, then cache suppression should occur. In the current experiment, we found that the birds maintained caching throughout the experiment. We report that males increased caching in response to a manipulation in which caches were artificially added, suggesting the birds could adapt to the cooperative nature of the task. Additionally, we show that caching decisions were not solely due to motivational factors, instead showing an additional influence attributed to the behavior of the partner bird.

  5. Clark’s Nutcrackers (Nucifraga columbiana) Flexibly Adapt Caching Behavior to a Cooperative Context

    PubMed Central

    Clary, Dawson; Kelly, Debbie M.

    2016-01-01

    Corvids recognize when their caches are at risk of being stolen by others and have developed strategies to protect these caches from pilferage. For instance, Clark’s nutcrackers will suppress the number of caches they make if being observed by a potential thief. However, cache protection has most often been studied using competitive contexts, so it is unclear whether corvids can adjust their caching in beneficial ways to accommodate non-competitive situations. Therefore, we examined whether Clark’s nutcrackers, a non-social corvid, would flexibly adapt their caching behaviors to a cooperative context. To do so, birds were given a caching task during which caches made by one individual were reciprocally exchanged for the caches of a partner bird over repeated trials. In this scenario, if caching behaviors can be flexibly deployed, then the birds should recognize the cooperative nature of the task and maintain or increase caching levels over time. However, if cache protection strategies are applied independent of social context and simply in response to cache theft, then cache suppression should occur. In the current experiment, we found that the birds maintained caching throughout the experiment. We report that males increased caching in response to a manipulation in which caches were artificially added, suggesting the birds could adapt to the cooperative nature of the task. Additionally, we show that caching decisions were not solely due to motivational factors, instead showing an additional influence attributed to the behavior of the partner bird. PMID:27826273

  6. Microwave behavior of silicon carbide/high alumina cement composites

    NASA Astrophysics Data System (ADS)

    Leiser, Kristie Sue

    2001-09-01

    Microwave susceptors have been fabricated from composites of silicon carbide/high alumina cement. These composites are very useful for microwave processing other materials. By using these composites for microwave hybrid heating, both ordinary and unique materials have the potential to be fabricated. The use of the susceptors can help to produce a more even temperature distribution across a material being microwave heated. This composite of silicon carbide particles embedded in high alumina cement only needed to be better characterized to enhance its applicability to more systems. This goal was accomplished in this study. During the course of the study, the factors affecting the heating rate of the composites were identified. These factors included silicon carbide particle size, weight percent silicon carbide in the composite, silicon carbide phase, processing atmosphere, and the maximum temperature experienced by the composite. A systematic study was designed to examine the importance of factors such as these and their effects upon the heating rate of high alumina cement/silicon carbide composites. Statistical design was employed to determine the significance of the factors of interest. The effects of these factors on the heating rate of the composites were determined. As the amount of silicon carbide in the composite increased, the heating rate tended to increase. The effects observed were explained by a combination of dielectric mixing equations, a heat transfer model and percolation theory. The silicon carbide particle size also affected the heating rate of the composites. Mathematical modeling showed that the particle size effect was a geometric effect that was dependent upon imperfect thermal contact between the silicon carbide particle and the cement matrix. The silicon carbide particle size also affected the percolation threshold of the composites. The heating rate of the composites increased when calcium carbonate present in the cement was pyrolyzed to form

  7. Adapting cognitive behavioral therapy to meet the needs of Chinese clients: Opportunities and challenges.

    PubMed

    Guo, Feng; Hanley, Terry

    2015-06-01

    With the growing influence of China (Chinese people/culture) on the world's politics, economy, and culture, the psychological wellbeing of Chinese people is becoming increasingly important for both researchers and practitioners. Despite this, the cultural responsiveness of many conventional psychotherapeutic models has often been brought into question. In contrast, cognitive behavioral therapy (CBT) is rapidly becoming one of the most popular approaches in the mental health service industry and has been successfully adapted into many different cultural contexts. The current article is a theoretical discussion of the opportunities and challenges that CBT faces with respect to how it might meet the cultural needs and preferences of Chinese clients. Suggestions for successful cultural adaptation are offered based on existing research and practices. It is concluded that many features of CBT appear to match well with the Chinese cultural perspective. However, despite this promising start further work is needed to focus specifically on its practical effectiveness for Chinese clients.

  8. Feed-forward mechanisms: addiction-like behavioral and molecular adaptations in overeating.

    PubMed

    Alsiö, Johan; Olszewski, Pawel K; Levine, Allen S; Schiöth, Helgi B

    2012-04-01

    Food reward, not hunger, is the main driving force behind eating in the modern obesogenic environment. Palatable foods, generally calorie-dense and rich in sugar/fat, are thus readily overconsumed despite the resulting health consequences. Important advances have been made to explain mechanisms underlying excessive consumption as an immediate response to presentation of rewarding tastants. However, our understanding of long-term neural adaptations to food reward that oftentimes persist during even a prolonged absence of palatable food and contribute to the reinstatement of compulsive overeating of high-fat high-sugar diets, is much more limited. Here we discuss the evidence from animal and human studies for neural and molecular adaptations in both homeostatic and non-homeostatic appetite regulation that may underlie the formation of a "feed-forward" system, sensitive to palatable food and propelling the individual from a basic preference for palatable diets to food craving and compulsive, addiction-like eating behavior.

  9. Facets and mechanisms of adaptive pain behavior: predictive regulation and action

    PubMed Central

    Morrison, India; Perini, Irene; Dunham, James

    2013-01-01

    Neural mechanisms underlying nociception and pain perception are considered to serve the ultimate goal of limiting tissue damage. However, since pain usually occurs in complex environments and situations that call for elaborate control over behavior, simple avoidance is insufficient to explain a range of mammalian pain responses, especially in the presence of competing goals. In this integrative review we propose a Predictive Regulation and Action (PRA) model of acute pain processing. It emphasizes evidence that the nervous system is organized to anticipate potential pain and to adjust behavior before the risk of tissue damage becomes critical. Regulatory processes occur on many levels, and can be dynamically influenced by local interactions or by modulation from other brain areas in the network. The PRA model centers on neural substrates supporting the predictive nature of pain processing, as well as on finely-calibrated yet versatile regulatory processes that ultimately affect behavior. We outline several operational categories of pain behavior, from spinally-mediated reflexes to adaptive voluntary action, situated at various neural levels. An implication is that neural processes that track potential tissue damage in terms of behavioral consequences are an integral part of pain perception. PMID:24348358

  10. Adapt

    NASA Astrophysics Data System (ADS)

    Bargatze, L. F.

    2015-12-01

    Active Data Archive Product Tracking (ADAPT) is a collection of software routines that permits one to generate XML metadata files to describe and register data products in support of the NASA Heliophysics Virtual Observatory VxO effort. ADAPT is also a philosophy. The ADAPT concept is to use any and all available metadata associated with scientific data to produce XML metadata descriptions in a consistent, uniform, and organized fashion to provide blanket access to the full complement of data stored on a targeted data server. In this poster, we present an application of ADAPT to describe all of the data products that are stored by using the Common Data File (CDF) format served out by the CDAWEB and SPDF data servers hosted at the NASA Goddard Space Flight Center. These data servers are the primary repositories for NASA Heliophysics data. For this purpose, the ADAPT routines have been used to generate data resource descriptions by using an XML schema named Space Physics Archive, Search, and Extract (SPASE). SPASE is the designated standard for documenting Heliophysics data products, as adopted by the Heliophysics Data and Model Consortium. The set of SPASE XML resource descriptions produced by ADAPT includes high-level descriptions of numerical data products, display data products, or catalogs and also includes low-level "Granule" descriptions. A SPASE Granule is effectively a universal access metadata resource; a Granule associates an individual data file (e.g. a CDF file) with a "parent" high-level data resource description, assigns a resource identifier to the file, and lists the corresponding assess URL(s). The CDAWEB and SPDF file systems were queried to provide the input required by the ADAPT software to create an initial set of SPASE metadata resource descriptions. Then, the CDAWEB and SPDF data repositories were queried subsequently on a nightly basis and the CDF file lists were checked for any changes such as the occurrence of new, modified, or deleted

  11. Chemical composition of whole body and carcass of Bos indicus and tropically adapted Bos taurus breeds.

    PubMed

    Bonilha, S F M; Tedeschi, L O; Packer, I U; Razook, A G; Nardon, R F; Figueiredo, L A; Alleoni, G F

    2011-09-01

    Relationships between the chemical composition of the 9th- to 11th-rib section and the chemical composition of the carcass and empty body were evaluated for Bos indicus (108 Nellore and 36 Guzerah; GuS) and tropically adapted Bos taurus (56 Caracu; CaS) bulls, averaging 20 to 24 mo of age at slaughter. Nellore cattle were represented by 56 animals from the selected herd (NeS) and 52 animals from the control herd (NeC). The CaS and GuS bulls were from selected herds. Selected herds were based on 20 yr of selection for postweaning BW. Carcass composition was obtained after grinding, homogenizing, sampling, and analyzing soft tissue and bones. Similarly, empty body composition was obtained after grinding, homogenizing, sampling, analyzing, and combining blood, hide, head + feet, viscera, and carcass. Bulls were separated into 2 groups. Group 1 was composed of 36 NeS, 36 NeC, 36 CaS, and 36 GuS bulls and had water, ether extract (EE), protein, and ash chemically determined in the 9th- to 11th-rib section and in the carcass. Group 2 was composed of 20 NeS, 16 NeC, and 20 CaS bulls and water, EE, protein, and ash were determined in the 9th- to 11th-rib section, carcass, and empty body. Linear regressions were developed between the carcass and the 9th- to 11th-rib section compositions for group 1 and between carcass and empty body compositions for group 2. The 9th- to 11th-rib section percentages of water (RWt) and EE (RF) predicted the percentages of carcass water (CWt) and carcass fat (CF) with high precision: CWt, % = 29.0806 + 0.4873 × RWt, % (r(2) = 0.813, SE = 1.06) and CF, % = 10.4037 + 0.5179 × RF, % (r(2) = 0.863, SE = 1.26), respectively. Linear regressions between percentage of CWt and CF and empty body water (EBWt) and empty body fat (EBF) were also predicted with high precision: EBWt, % = -9.6821 + 1.1626 × CWt, % (r(2) = 0.878, SE = 1.43) and EBF, % = 0.3739 + 1.0386 × CF, % (r(2) = 0.982, SE = 0.65), respectively. Chemical composition of the 9th- to 11

  12. Lasting Adaptations in Social Behavior Produced by Social Disruption and Inhibition of Adult Neurogenesis

    PubMed Central

    Opendak, Maya; Offit, Lily; Monari, Patrick; Schoenfeld, Timothy J.; Sonti, Anup N.; Cameron, Heather A.

    2016-01-01

    Research on social instability has focused on its detrimental consequences, but most people are resilient and respond by invoking various coping strategies. To investigate cellular processes underlying such strategies, a dominance hierarchy of rats was formed and then destabilized. Regardless of social position, rats from disrupted hierarchies had fewer new neurons in the hippocampus compared with rats from control cages and those from stable hierarchies. Social disruption produced a preference for familiar over novel conspecifics, a change that did not involve global memory impairments or increased anxiety. Using the neuropeptide oxytocin as a tool to increase neurogenesis in the hippocampus of disrupted rats restored preference for novel conspecifics to predisruption levels. Conversely, reducing the number of new neurons by limited inhibition of adult neurogenesis in naive transgenic GFAP–thymidine kinase rats resulted in social behavior similar to disrupted rats. Together, these results provide novel mechanistic evidence that social disruption shapes behavior in a potentially adaptive way, possibly by reducing adult neurogenesis in the hippocampus. SIGNIFICANCE STATEMENT To investigate cellular processes underlying adaptation to social instability, a dominance hierarchy of rats was formed and then destabilized. Regardless of social position, rats from disrupted hierarchies had fewer new neurons in the hippocampus compared with rats from control cages and those from stable hierarchies. Unexpectedly, these changes were accompanied by changes in social strategies without evidence of impairments in cognition or anxiety regulation. Restoring adult neurogenesis in disrupted rats using oxytocin and conditionally suppressing the production of new neurons in socially naive GFAP–thymidine kinase rats showed that loss of 6-week-old neurons may be responsible for adaptive changes in social behavior. PMID:27358459

  13. Post-impact behavior of composite solid rocket motor cases

    NASA Technical Reports Server (NTRS)

    Highsmith, Alton L.

    1992-01-01

    In recent years, composite materials have seen increasing use in advanced structural applications because of the significant weight savings they offer when compared to more traditional engineering materials. The higher cost of composites must be offset by the increased performance that results from reduced structural weight if these new materials are to be used effectively. At present, there is considerable interest in fabricating solid rocket motor cases out of composite materials, and capitalizing on the reduced structural weight to increase rocket performance. However, one of the difficulties that arises when composite materials are used is that composites can develop significant amounts of internal damage during low velocity impacts. Such low velocity impacts may be encountered in routine handling of a structural component like a rocket motor case. The ability to assess the reduction in structural integrity of composite motor cases that experience accidental impacts is essential if composite rocket motor cases are to be certified for manned flight. The study described herein was an initial investigation of damage development and reduction of tensile strength in an idealized composite subjected to low velocity impacts.

  14. Behavior Change Interventions to Improve the Health of Racial and Ethnic Minority Populations: A Tool Kit of Adaptation Approaches

    PubMed Central

    Davidson, Emma M; Liu, Jing Jing; Bhopal, Raj; White, Martin; Johnson, Mark RD; Netto, Gina; Wabnitz, Cecile; Sheikh, Aziz

    2013-01-01

    Context Adapting behavior change interventions to meet the needs of racial and ethnic minority populations has the potential to enhance their effectiveness in the target populations. But because there is little guidance on how best to undertake these adaptations, work in this field has proceeded without any firm foundations. In this article, we present our Tool Kit of Adaptation Approaches as a framework for policymakers, practitioners, and researchers interested in delivering behavior change interventions to ethnically diverse, underserved populations in the United Kingdom. Methods We undertook a mixed-method program of research on interventions for smoking cessation, increasing physical activity, and promoting healthy eating that had been adapted to improve salience and acceptability for African-, Chinese-, and South Asian–origin minority populations. This program included a systematic review (reported using PRISMA criteria), qualitative interviews, and a realist synthesis of data. Findings We compiled a richly informative data set of 161 publications and twenty-six interviews detailing the adaptation of behavior change interventions and the contexts in which they were undertaken. On the basis of these data, we developed our Tool Kit of Adaptation Approaches, which contains (1) a forty-six-item Typology of Adaptation Approaches; (2) a Pathway to Adaptation, which shows how to use the Typology to create a generic behavior change intervention; and (3) RESET, a decision tool that provides practical guidance on which adaptations to use in different contexts. Conclusions Our Tool Kit of Adaptation Approaches provides the first evidence-derived suite of materials to support the development, design, implementation, and reporting of health behavior change interventions for minority groups. The Tool Kit now needs prospective, empirical evaluation in a range of intervention and population settings. PMID:24320170

  15. The Applied Behavior Analysis Research Paradigm and Single-Subject Designs in Adapted Physical Activity Research.

    PubMed

    Haegele, Justin A; Hodge, Samuel Russell

    2015-10-01

    There are basic philosophical and paradigmatic assumptions that guide scholarly research endeavors, including the methods used and the types of questions asked. Through this article, kinesiology faculty and students with interests in adapted physical activity are encouraged to understand the basic assumptions of applied behavior analysis (ABA) methodology for conducting, analyzing, and presenting research of high quality in this paradigm. The purposes of this viewpoint paper are to present information fundamental to understanding the assumptions undergirding research methodology in ABA, describe key aspects of single-subject research designs, and discuss common research designs and data-analysis strategies used in single-subject studies.

  16. The changing brain--insights into the mechanisms of neural and behavioral adaptation to the environment.

    PubMed

    Bergersen, L H; Bramham, C R; Hugdahl, K; Sander, M; Storm-Mathisen, J

    2013-09-05

    The Kavli Prize in Neuroscience was awarded for the third time in September 2012, by the Norwegian Academy of Science and Letters in Oslo. The accompanying Kavli Prize Symposium on Neuroscience, held in Bergen and Trondheim, was a showcase of excellence in neuroscience research. The common theme of the Symposium presentations was the mechanisms by which animals adapt to their environment. The symposium speakers--Michael Greenberg, Erin Schuman, Chiara Cirelli, Michael Meaney, Catherine Dulac, Hopi Hoekstra, and Stanislas Dehaene--covered topics ranging from the molecular and cellular levels to the systems level and behavior. Thus a single amino acid change in a transcriptional repressor can disrupt gene regulation through neural activity (Greenberg). Deep sequencing analysis of the neuropil transcriptome indicates that a large fraction of the synaptic proteome is synthesized in situ in axons and dendrites, permitting local regulation (Schuman). The nature of the 'reset' function that makes animals dependent of sleep is being revealed (Cirelli). Maternal behavior can cause changes in gene expression that stably modify behavior in the offspring (Meaney). Removal of a single sensory channel protein in the vomero-nasal organ can switch off male-specific and switch on female-specific innate behavior of mice in response to environmental stimulation (Dulac). Innate behaviors can be stably transmitted from parent to offspring through generations even when those behaviors cannot be expressed, as illustrated by the elaborate burrowing behavior in a rodent species, in which independent genetic regions regulate distinct modules of the burrowing pattern (Hoekstra). Finally, at the other extreme of the nature-nurture scale, functional magnetic resonance imaging (fMRI) analysis in children and adults identified a brain area specifically involved in reading (Dehaene). As the area must originally have developed for a purpose other than reading, such as shape recognition, this

  17. Life-history evolution at the molecular level: adaptive amino acid composition of avian vitellogenins

    PubMed Central

    Hughes, Austin L.

    2015-01-01

    Avian genomes typically encode three distinct vitellogenin (VTG) egg yolk proteins (VTG1, VTG2 and VTG3), which arose by gene duplication prior to the most recent common ancestor of birds. Analysis of VTG sequences from 34 avian species in a phylogenetic framework supported the hypothesis that VTG amino acid composition has co-evolved with embryo incubation time. Embryo incubation time was positively correlated with the proportions of dietary essential amino acids (EAAs) in VTG1 and VTG2, and with the proportion of sulfur-containing amino acids in VTG3. These patterns were seen even when only semi-altricial and/or altricial species were considered, suggesting that the duration of embryo incubation is a major selective factor on the amino acid composition of VTGs, rather than developmental mode alone. The results are consistent with the hypothesis that the level of EAAs provided to the egg represents an adaptation to the loss of amino acids through breakdown over the course of incubation and imply that life-history phenotypes and VTG amino acid composition have co-evolved throughout the evolutionary history of birds. PMID:26224713

  18. [Translation and adaptation of the Motorcycle Rider Behavior Questionnaire: a Brazilian version].

    PubMed

    Coelho, Roberta Paula Schell; Grassi-Oliveira, Rodrigo; Machado, Mônica; Williams, Anna Virginia; Matte, Breno Córdova; Pechansky, Flavio; Rohde, Luis Augusto Paim; Szobot, Claudia Maciel

    2012-06-01

    Traffic accidents are a leading cause of death in young adults. In Brazil, traffic accidents are proportionally more prevalent among motorcyclists as compared to automobile drivers. Although numerous data indicate that individual characteristics are involved in traffic accident risk, there is no instrument in Brazil to assess motorcyclists' traffic behavior. The authors thus proposed to perform translation and cultural adaptation of the Motorcycle Rider Behavior Questionnaire (MRBQ) into Brazilian Portuguese. The translation process consisted of: two independent translations into Brazilian Portuguese; unification of the translations; back-translation into English; formal assessment of semantic equivalence; application of a summary version in a convenience sample of motorcyclists; generation of a final version; and back-translation and submission to the original author, who approved this version. The Brazilian version maintained its semantic equivalence and was accepted by the convenience sample, an important characteristic for a self-completed instrument. Further studies are necessary to evaluate the questionnaire's psychometric properties in the Brazilian cultural context.

  19. Effect of lining with a flowable composite on internal adaptation of direct composite restorations using all-in-one adhesive systems.

    PubMed

    Yahagi, Chika; Takagaki, Tomohiro; Sadr, Alireza; Ikeda, Masaomi; Nikaido, Toru; Tagami, Junji

    2012-01-01

    The purpose of this study was to evaluate the effect of lining with a flowable composite on internal adaptation of composite restorations using three all-in-one adhesive systems; Bond Force (BF), G-Bond Plus (GP), and OptiBond All-in-one (OP), and a two-step self-etching adhesive system; Clearfil SE Bond (SE). They were applied to each cylindrical cavity prepared on the human dentin. The cavity surface was lined with/without a flowable resin composite prior to filling with a resin composite (FL/NL). After water storage for 24 h, the specimens were sectioned and polished, and internal adaptation of the restorations was assessed using a confocal laser scanning microscopy. For SE, a perfect cavity adaptation was recognized in both FL and NL. For BF, GP and OP, cavity adaptation was material dependent in NL, whereas no gap formation was observed in FL. However, voids formation was observed at the composite-adhesive-dentin interface in every all-in-one adhesive system.

  20. Friction and wear behavior of graphite fiber reinforced polymide composites

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.; Sliney, H. E.

    1977-01-01

    The friction and wear rate characteristics of 50/50 (weight percent) graphite fiber polyimide composites were studied by sliding metallic hemispherically tipped riders against disks made from the composites. Two different polyimides and two different graphite fibers were evaluated. Also studied were such variables as the effect of moisture in an air atmosphere; the effect of temperature; and the effect of different sliding speeds. In general, wear to the the metallic riders was negligible, and composite wear increased at a constant rate as a function of number of sliding cycles.

  1. Temper tantrums in young children: 1. Behavioral composition.

    PubMed

    Potegal, Michael; Davidson, Richard J

    2003-06-01

    Although tantrums are among the most common behavioral problems of young children and may predict future antisocial behavior, little is known about them. To develop a model of this important phenomenon of early childhood, behaviors reported in parental narratives of the tantrums of 335 children aged 18 to 60 months were encoded as present or absent in consecutive 30-second periods. Principal Component (PC) analysis identified Anger and Distress as major, independent emotional and behavioral tantrum constituents. Anger-related behaviors formed PCs at three levels of intensity. High-intensity anger decreased with age, and low-intensity anger increased. Distress, the fourth PC, consisted of whining, crying, and comfort-seeking. Coping Style, the fifth PC, had high but opposite loadings on dropping down and running away, possibly reflecting the tendency to either "submit" or "escape." Model validity was indicated by significant correlations of the PCs with tantrum variables that were, by design, not included in the PC analysis.

  2. Sex differences in autism spectrum disorders: does sex moderate the pathway from clinical symptoms to adaptive behavior?

    PubMed

    Mandic-Maravic, Vanja; Pejovic-Milovancevic, Milica; Mitkovic-Voncina, Marija; Kostic, Milutin; Aleksic-Hil, Olivera; Radosavljev-Kircanski, Jelena; Mincic, Teodora; Lecic-Tosevski, Dusica

    2015-05-19

    We explored sex differences in diagnostic categories, clinical symptoms and adaptive behavior of persons with autism spectrum disorders, as well as sex-specific correlations of clinical and adaptive caracteristics. The study involved 108 patients (83 males, 6.73 ± 4.33 years old) diagnosed with autism spectrum disorders (ASD). Assessment included ADI-R and Vineland Adaptive Behavior Scale II. Males were more often diagnosed with typical autism. There were no sex differences in the autistic symptoms, while females showed better functioning in Daily living skills, without reaching statistically significant difference (p = 0.062). We have found different associations of autistic symptoms with different aspects of adaptive behavior in males and females. Social reciprocity in females correlated with social domain of adaptive behavior, in a positive direction. Our findings have shown that although there are no sex differences in autistic symptoms, females tend to be somewhat more functional, and are also less frequently diagnosed with typical autism. Our results have also shown that sex might moderate the way clinical symptoms are expressed in adaptive behavior. Social reciprocity might be the core feature regarding sex differences in ASD. Our findings might have diagnostic and therapeutical implications, pointing out to the need for individualized, sex-specific treatment in this group of disorders.

  3. Children with Autism and Attention Difficulties: A Pilot Study of the Association between Sensory, Motor, and Adaptive Behaviors

    PubMed Central

    Mattard-Labrecque, Carolanne; Ben Amor, Leila; Couture, Mélanie M.

    2013-01-01

    Objectives: This pilot study aimed to compare sensory processing, motor skills and adaptive behaviors in children with a double diagnosis of Autism Spectrum Disorder (ASD) and Attention Deficit Hyperactivity Disorder (ADHD) (ASD+ADHD) with children with ADHD alone and to examine the association of sensory processing and motor skills with adaptive behaviors (self-care). Method: Thirty children aged 5–14 years diagnosed with ASD+ADHD (n = 13) or ADHD (n = 17) were evaluated on their sensory processing and motor skills and adaptive behaviors. Analysis of covariance compared the groups on these dimensions. Correlation analyses examined the association between sensory processing and motor skills and adaptive behaviors. Results: Compared to children with ADHD alone, children with ASD+ADHD had poorer skills in sensory processing (p < 0.001), motor (p = 0.001) and adaptive behaviors (p < 0.001). For all children, increased autonomy in self-care was correlated with better sensory processing (p < 0.001) and motor skills (p = 0.002). Conclusion: Children with ASD+ADHD have poorer sensory processing, motor and adaptive skills than those with ADHD alone. Sensory processing and motor deficits were negatively associated with autonomy in self-care. Interventions aiming to improve sensory processing and motor skills and autonomy in self-care should become important targets for these children. PMID:23667360

  4. Cognitive Abilities, Social Adaptation, and Externalizing Behavior Problems in Childhood and Adolescence: Specific Cascade Effects Across Development.

    PubMed

    Racz, Sarah Jensen; Putnick, Diane L; Suwalsky, Joan T D; Hendricks, Charlene; Bornstein, Marc H

    2016-11-04

    Children's and adolescents' cognitive abilities, social adaptation, and externalizing behaviors are broadly associated with each other at the bivariate level; however, the direction, ordering, and uniqueness of these associations have yet to be identified. Developmental cascade models are particularly well-suited to (1) discern unique pathways among psychological domains and (2) model stability in and covariation among constructs, allowing for conservative tests of longitudinal associations. The current study aimed to identify specific cascade effects among children's cognitive abilities, social adaptation, and externalizing behaviors, beginning in preschool and extending through adolescence. Children (46.2 % female) and mothers (N = 351 families) provided data when children were 4, 10, and 14 years old. Cascade effects highlighted significant stability in these domains. Unique longitudinal associations were identified between (1) age-10 cognitive abilities and age-14 social adaptation, (2) age-4 social adaptation and age-10 externalizing behavior, and (3) age-10 externalizing behavior and age-14 social adaptation. These findings suggest that children's social adaptation in preschool and externalizing behavior in middle childhood may be ideal intervention targets to enhance adolescent well-being.

  5. Aging behavior and life prediction of graphite composites

    NASA Technical Reports Server (NTRS)

    Ramohalli, Kumar; Raasch, David

    1989-01-01

    This paper presents experimental data from two independent tests, designed to determine the long-term reliability of composite materials. The technique of accelerated aging at elevated temperatures is employed. In the first set, graphite fiber, epoxy composites in five ply layups are manufactured and tested in the standard short-beam shear mode. In the second set, Nomex honeycomb, graphite fiber/epoxy composite face and rear sheet sandwich coupons are tested. After satisfying simple consistency checks, data interpretation is attempted within the framework of an Arrhenius degradation model. The elevated temperature is assumed to influence the degradation according to this temperature-dependent rate law. From these tests on five-ply composites and honeycomb sandwiches, it is concluded that aging is not a serious problem.

  6. The behavior of delaminations in composite materials - experimental results

    NASA Astrophysics Data System (ADS)

    Chermoshentseva, A. S.; Pokrovskiy, A. M.; Bokhoeva, L. A.

    2016-02-01

    Delamination is one of the most common failure modes of composite materials. It may occur as a consequence of imperfections in the production process or the effects of external factors during the operational life of the composite laminates, such as the impact by foreign objects. This paper presents the results of mechanical tests and the optimum degrees of filling the composite materials (CM) with hydrophobic powder (Tarkosil T-20) depending on the latter mass concentration. The results present test samples of the CM with the underlying interlayer defects. The samples were fabricated of twenty-ply pre-preg (fiberglass or carbon fiber). The industrial grade glass is T-25 (VM) specification 6-11-380-76. The composite materials have nanosized additives in structure. The volume concentration of nanopowders is varying from 0.1% to 0.5%. This kind of research has been done for the first time.

  7. Thermal-mechanical behavior of high precision composite mirrors

    NASA Astrophysics Data System (ADS)

    Kuo, C. P.; Lou, M. C.; Rapp, D.

    1993-04-01

    Composite mirror panels were designed, constructed, analyzed, and tested in the framework of a NASA precision segmented reflector task. The deformations of the reflector surface during the exposure to space enviroments were predicted using a finite element model. The composite mirror panels have graphite-epoxy or graphite-cyanate facesheets, separated by an aluminum or a composite honeycomb core. It is pointed out that in order to carry out detailed modeling of composite mirrors with high accuracy, it is necessary to have temperature dependent properties of the materials involved and the type and magnitude of manufacturing errors and material nonuniformities. The structural modeling and analysis efforts addressed the impact of key design and materials parameters on the performance of mirrors.

  8. High Strain Rate Behavior of Polymer Matrix Composites Analyzed

    NASA Technical Reports Server (NTRS)

    Goldberg, Robert K.; Roberts, Gary D.

    2001-01-01

    Procedures for modeling the high-speed impact of composite materials are needed for designing reliable composite engine cases that are lighter than the metal cases in current use. The types of polymer matrix composites that are likely to be used in such an application have a deformation response that is nonlinear and that varies with strain rate. To characterize and validate material models that could be used in the design of impactresistant engine cases, researchers must obtain material data over a wide variety of strain rates. An experimental program has been carried out through a university grant with the Ohio State University to obtain deformation data for a representative polymer matrix composite for strain rates ranging from quasi-static to high rates of several hundred per second. This information has been used to characterize and validate a constitutive model that was developed at the NASA Glenn Research Center.

  9. Cold microgradients elicit adaptive behavior in isotropically cooled, inert populations of Oxytricha bifaria (Ciliophora, Hypotrichida).

    PubMed

    Barbanera, F; Erra, F; Ricci, N

    2000-01-01

    To complete our investigations on the oriented behavioral response of isotropically cooled, inert populations of Oxytricha bifaria to a warm thermal gradient, their physiological potentialities under cold microgradient conditions arising at 8.5 degrees C were studied. We monitored the behavior of the experimental populations, both at the level of the passing cold wave front, and afterwards when the thermal gradient stabilized, evaluating (i) their distribution in general, (ii) their relative centroids, (iii) the percentage of both backward creeping and immobile ciliates, and (iv) the numerical indices and rates of their creeping tracks. At the arrival of the cold wave front, the oxytrichas react immediately to the thermal stimulus, creep backwards at very high velocity along uninterrupted linear tracks, and thus move away from the cooling source. No specific behavioral response was ever observed in the static microgradient conditions. At 8.5 degrees C, despite their inertness, the ciliates are still able to behave adaptively, reacting immediately and orientatedly, once a directional factor (the cold-repelling thermal gradient) arises in an isotropic environment. This is similar to their behavior in the symmetric warm attracting thermal gradient.

  10. Genomic Response to Selection for Predatory Behavior in a Mammalian Model of Adaptive Radiation.

    PubMed

    Konczal, Mateusz; Koteja, Paweł; Orlowska-Feuer, Patrycja; Radwan, Jacek; Sadowska, Edyta T; Babik, Wiesław

    2016-09-01

    If genetic architectures of various quantitative traits are similar, as studies on model organisms suggest, comparable selection pressures should produce similar molecular patterns for various traits. To test this prediction, we used a laboratory model of vertebrate adaptive radiation to investigate the genetic basis of the response to selection for predatory behavior and compare it with evolution of aerobic capacity reported in an earlier work. After 13 generations of selection, the proportion of bank voles (Myodes [=Clethrionomys] glareolus) showing predatory behavior was five times higher in selected lines than in controls. We analyzed the hippocampus and liver transcriptomes and found repeatable changes in allele frequencies and gene expression. Genes with the largest differences between predatory and control lines are associated with hunger, aggression, biological rhythms, and functioning of the nervous system. Evolution of predatory behavior could be meaningfully compared with evolution of high aerobic capacity, because the experiments and analyses were performed in the same methodological framework. The number of genes that changed expression was much smaller in predatory lines, and allele frequencies changed repeatably in predatory but not in aerobic lines. This suggests that more variants of smaller effects underlie variation in aerobic performance, whereas fewer variants of larger effects underlie variation in predatory behavior. Our results thus contradict the view that comparable selection pressures for different quantitative traits produce similar molecular patterns. Therefore, to gain knowledge about molecular-level response to selection for complex traits, we need to investigate not only multiple replicate populations but also multiple quantitative traits.

  11. LABRADOR: a learning autonomous behavior-based robot for adaptive detection and object retrieval

    NASA Astrophysics Data System (ADS)

    Yamauchi, Brian; Moseley, Mark; Brookshire, Jonathan

    2013-01-01

    As part of the TARDEC-funded CANINE (Cooperative Autonomous Navigation in a Networked Environment) Program, iRobot developed LABRADOR (Learning Autonomous Behavior-based Robot for Adaptive Detection and Object Retrieval). LABRADOR was based on the rugged, man-portable, iRobot PackBot unmanned ground vehicle (UGV) equipped with an explosives ordnance disposal (EOD) manipulator arm and a custom gripper. For LABRADOR, we developed a vision-based object learning and recognition system that combined a TLD (track-learn-detect) filter based on object shape features with a color-histogram-based object detector. Our vision system was able to learn in real-time to recognize objects presented to the robot. We also implemented a waypoint navigation system based on fused GPS, IMU (inertial measurement unit), and odometry data. We used this navigation capability to implement autonomous behaviors capable of searching a specified area using a variety of robust coverage strategies - including outward spiral, random bounce, random waypoint, and perimeter following behaviors. While the full system was not integrated in time to compete in the CANINE competition event, we developed useful perception, navigation, and behavior capabilities that may be applied to future autonomous robot systems.

  12. The aqueous corrosion behavior of technetium - Alloy and composite materials

    SciTech Connect

    Jarvinen, G.; Kolman, D.; Taylor, C.; Goff, G.; Cisneros, M.; Mausolf, E.; Poineau, F.; Koury, D.; Czerwinski, K.

    2013-07-01

    Metal waste forms are under study as possible disposal forms for technetium and other fission products. The alloying of Tc is desirable to reduce the melting point of the Tc-containing metal waste form and potentially improve its corrosion resistance. Technetium-nickel composites were made by mixing the two metal powders and pressing the mixture to make a pellet. The as-pressed composite materials were compared to sintered composites and alloys of identical composition in electrochemical corrosion tests. As-pressed samples were not robust enough for fine polishing and only a limited number of corrosion tests were performed. Alloys and composites with 10 wt% Tc appear to be more corrosion resistant at open circuit than the individual components based on linear polarization resistance and polarization data. The addition of 10 wt% Tc to Ni appears beneficial at open circuit, but detrimental upon anodic polarization. Qualitatively, the polarizations of 10 wt% Tc alloys and composites appear like crude addition of Tc plus Ni. The 1 wt% Tc alloys behave like pure Ni, but some effect of Tc is seen upon polarization. Cathodic polarization of Tc by Ni appears feasible based on open circuit potential measurements, however, zero resistance ammetry and solution measurements are necessary to confirm cathodic protection.

  13. Model-on-Demand Predictive Control for Nonlinear Hybrid Systems With Application to Adaptive Behavioral Interventions

    PubMed Central

    Nandola, Naresh N.; Rivera, Daniel E.

    2011-01-01

    This paper presents a data-centric modeling and predictive control approach for nonlinear hybrid systems. System identification of hybrid systems represents a challenging problem because model parameters depend on the mode or operating point of the system. The proposed algorithm applies Model-on-Demand (MoD) estimation to generate a local linear approximation of the nonlinear hybrid system at each time step, using a small subset of data selected by an adaptive bandwidth selector. The appeal of the MoD approach lies in the fact that model parameters are estimated based on a current operating point; hence estimation of locations or modes governed by autonomous discrete events is achieved automatically. The local MoD model is then converted into a mixed logical dynamical (MLD) system representation which can be used directly in a model predictive control (MPC) law for hybrid systems using multiple-degree-of-freedom tuning. The effectiveness of the proposed MoD predictive control algorithm for nonlinear hybrid systems is demonstrated on a hypothetical adaptive behavioral intervention problem inspired by Fast Track, a real-life preventive intervention for improving parental function and reducing conduct disorder in at-risk children. Simulation results demonstrate that the proposed algorithm can be useful for adaptive intervention problems exhibiting both nonlinear and hybrid character. PMID:21874087

  14. A Novel Model Predictive Control Formulation for Hybrid Systems With Application to Adaptive Behavioral Interventions

    PubMed Central

    Nandola, Naresh N.; Rivera, Daniel E.

    2010-01-01

    This paper presents a novel model predictive control (MPC) formulation for linear hybrid systems. The algorithm relies on a multiple-degree-of-freedom formulation that enables the user to adjust the speed of setpoint tracking, measured disturbance rejection and unmeasured disturbance rejection independently in the closed-loop system. Consequently, controller tuning is more flexible and intuitive than relying on move suppression weights as traditionally used in MPC schemes. The formulation is motivated by the need to achieve robust performance in using the algorithm in emerging applications, for instance, as a decision policy for adaptive, time-varying interventions used in behavioral health. The proposed algorithm is demonstrated on a hypothetical adaptive intervention problem inspired by the Fast Track program, a real-life preventive intervention for improving parental function and reducing conduct disorder in at-risk children. Simulation results in the presence of simultaneous disturbances and significant plant-model mismatch are presented. These demonstrate that a hybrid MPC-based approach for this class of interventions can be tuned for desired performance under demanding conditions that resemble participant variability that is experienced in practice when applying an adaptive intervention to a population. PMID:20830213

  15. Neocortical Tet3-mediated accumulation of 5-hydroxymethylcytosine promotes rapid behavioral adaptation.

    PubMed

    Li, Xiang; Wei, Wei; Zhao, Qiong-Yi; Widagdo, Jocelyn; Baker-Andresen, Danay; Flavell, Charlotte R; D'Alessio, Ana; Zhang, Yi; Bredy, Timothy W

    2014-05-13

    5-hydroxymethylcytosine (5-hmC) is a novel DNA modification that is highly enriched in the adult brain and dynamically regulated by neural activity. 5-hmC accumulates across the lifespan; however, the functional relevance of this change in 5-hmC and whether it is necessary for behavioral adaptation have not been fully elucidated. Moreover, although the ten-eleven translocation (Tet) family of enzymes is known to be essential for converting methylated DNA to 5-hmC, the role of individual Tet proteins in the adult cortex remains unclear. Using 5-hmC capture together with high-throughput DNA sequencing on individual mice, we show that fear extinction, an important form of reversal learning, leads to a dramatic genome-wide redistribution of 5-hmC within the infralimbic prefrontal cortex. Moreover, extinction learning-induced Tet3-mediated accumulation of 5-hmC is associated with the establishment of epigenetic states that promote gene expression and rapid behavioral adaptation.

  16. Effects of sex and gender on adaptation to space: behavioral health.

    PubMed

    Goel, Namni; Bale, Tracy L; Epperson, C Neill; Kornstein, Susan G; Leon, Gloria R; Palinkas, Lawrence A; Stuster, Jack W; Dinges, David F

    2014-11-01

    This article is part of a larger body of work entitled, "The Impact of Sex and Gender on Adaptation to Space." It was developed in response to a recommendation from the 2011 National Academy of Sciences Decadal Survey, "Recapturing a Future for Space Exploration: Life and Physical Sciences for a New Era," which emphasized the need to fully understand sex and gender differences. In this article, our workgroup-consisting of expert scientists and clinicians from academia and the private sector-investigated and summarized the current body of published and unpublished human research performed to date related to sex- and gender-based differences in behavioral adaptations to human spaceflight. This review identifies sex-related differences in: (1) sleep, circadian rhythms, and neurobehavioral measures; (2) personality, group interactions, and work performance and satisfaction; and (3) stress and clinical disorders. Differences in these areas substantially impact the risks and optimal medical care required by space-faring women. To ensure the health and safety of male and female astronauts during long-duration space missions, it is imperative to understand the influences that sex and gender have on behavioral health changes occurring during spaceflight.

  17. Effects of Sex and Gender on Adaptation to Space: Behavioral Health

    PubMed Central

    Bale, Tracy L.; Epperson, C. Neill; Kornstein, Susan G.; Leon, Gloria R.; Palinkas, Lawrence A.; Stuster, Jack W.; Dinges, David F.

    2014-01-01

    Abstract This article is part of a larger body of work entitled, “The Impact of Sex and Gender on Adaptation to Space.” It was developed in response to a recommendation from the 2011 National Academy of Sciences Decadal Survey, “Recapturing a Future for Space Exploration: Life and Physical Sciences for a New Era,” which emphasized the need to fully understand sex and gender differences. In this article, our workgroup—consisting of expert scientists and clinicians from academia and the private sector—investigated and summarized the current body of published and unpublished human research performed to date related to sex- and gender-based differences in behavioral adaptations to human spaceflight. This review identifies sex-related differences in: (1) sleep, circadian rhythms, and neurobehavioral measures; (2) personality, group interactions, and work performance and satisfaction; and (3) stress and clinical disorders. Differences in these areas substantially impact the risks and optimal medical care required by space-faring women. To ensure the health and safety of male and female astronauts during long-duration space missions, it is imperative to understand the influences that sex and gender have on behavioral health changes occurring during spaceflight. PMID:25259837

  18. Adaptive and Context-Aware Reconciliation of Reactive and Pro-active Behavior in Evolving Systems

    NASA Astrophysics Data System (ADS)

    Trajcevski, Goce; Scheuermann, Peter

    One distinct characteristics of the context-aware systems is their ability to react and adapt to the evolution of the environment, which is often a result of changes in the values of various (possibly correlated) attributes. Based on these changes, reactive systems typically take corrective actions, e.g., adjusting parameters in order to maintain the desired specifications of the system's state. Pro-active systems, on the other hand, may change the mode of interaction with the environment as well as the desired goals of the system. In this paper we describe our (ECA)2 paradigm for reactive behavior with proactive impact and we present our ongoing work and vision for a system that is capable of context-aware adaptation, while ensuring the maintenance of a set of desired behavioral policies. Our main focus is on developing a formalism that provides tools for expressing normal, as well as defeasible and/or exceptional specification. However, at the same time, we insist on a sound semantics and the capability of answering hypothetical "what-if" queries. Towards this end, we introduce the high-level language L_{ EAR} that can be used to describe the dynamics of the problem domain, specify triggers under the (ECA)2 paradigm, and reason about the consequences of the possible evolutions.

  19. Contextualizing the "Behavior Gap": Student Prosocial Behavior and Racial Composition in Urban Middle Schools

    ERIC Educational Resources Information Center

    Voight, Adam M.; Geller, Joanna D.; Nation, Maury

    2014-01-01

    Encouraging student prosocial behavior (PSB) is a challenge for urban middle schools. The issue of student behavior is a racialized one, as Black students generally evince more negative behavioral outcomes than their White peers. This racial "behavior gap" may be conditional on the school environment. This study examines how one element…

  20. Microstructure and mechanical behavior of metallic glass fiber-reinforced Al alloy matrix composites.

    PubMed

    Wang, Z; Georgarakis, K; Nakayama, K S; Li, Y; Tsarkov, A A; Xie, G; Dudina, D; Louzguine-Luzgin, D V; Yavari, A R

    2016-04-12

    Metallic glass-reinforced metal matrix composites are an emerging class of composite materials. The metallic nature and the high mechanical strength of the reinforcing phase offers unique possibilities for improving the engineering performance of composites. Understanding the structure at the amorphous/crystalline interfaces and the deformation behavior of these composites is of vital importance for their further development and potential application. In the present work, Zr-based metallic glass fibers have been introduced in Al7075 alloy (Al-Zn-Mg-Cu) matrices using spark plasma sintering (SPS) producing composites with low porosity. The addition of metallic glass reinforcements in the Al-based matrix significantly improves the mechanical behavior of the composites in compression. High-resolution TEM observations at the interface reveal the formation of a thin interdiffusion layer able to provide good bonding between the reinforcing phase and the Al-based matrix. The deformation behavior of the composites was studied, indicating that local plastic deformation occurred in the matrix near the glassy reinforcements followed by the initiation and propagation of cracks mainly through the matrix. The reinforcing phase is seen to inhibit the plastic deformation and retard the crack propagation. The findings offer new insights into the mechanical behavior of metal matrix composites reinforced with metallic glasses.

  1. Microstructure and mechanical behavior of metallic glass fiber-reinforced Al alloy matrix composites

    NASA Astrophysics Data System (ADS)

    Wang, Z.; Georgarakis, K.; Nakayama, K. S.; Li, Y.; Tsarkov, A. A.; Xie, G.; Dudina, D.; Louzguine-Luzgin, D. V.; Yavari, A. R.

    2016-04-01

    Metallic glass-reinforced metal matrix composites are an emerging class of composite materials. The metallic nature and the high mechanical strength of the reinforcing phase offers unique possibilities for improving the engineering performance of composites. Understanding the structure at the amorphous/crystalline interfaces and the deformation behavior of these composites is of vital importance for their further development and potential application. In the present work, Zr-based metallic glass fibers have been introduced in Al7075 alloy (Al-Zn-Mg-Cu) matrices using spark plasma sintering (SPS) producing composites with low porosity. The addition of metallic glass reinforcements in the Al-based matrix significantly improves the mechanical behavior of the composites in compression. High-resolution TEM observations at the interface reveal the formation of a thin interdiffusion layer able to provide good bonding between the reinforcing phase and the Al-based matrix. The deformation behavior of the composites was studied, indicating that local plastic deformation occurred in the matrix near the glassy reinforcements followed by the initiation and propagation of cracks mainly through the matrix. The reinforcing phase is seen to inhibit the plastic deformation and retard the crack propagation. The findings offer new insights into the mechanical behavior of metal matrix composites reinforced with metallic glasses.

  2. Microstructure and mechanical behavior of metallic glass fiber-reinforced Al alloy matrix composites

    PubMed Central

    Wang, Z.; Georgarakis, K.; Nakayama, K. S.; Li, Y.; Tsarkov, A. A.; Xie, G.; Dudina, D.; Louzguine-Luzgin, D. V.; Yavari, A. R.

    2016-01-01

    Metallic glass-reinforced metal matrix composites are an emerging class of composite materials. The metallic nature and the high mechanical strength of the reinforcing phase offers unique possibilities for improving the engineering performance of composites. Understanding the structure at the amorphous/crystalline interfaces and the deformation behavior of these composites is of vital importance for their further development and potential application. In the present work, Zr-based metallic glass fibers have been introduced in Al7075 alloy (Al-Zn-Mg-Cu) matrices using spark plasma sintering (SPS) producing composites with low porosity. The addition of metallic glass reinforcements in the Al-based matrix significantly improves the mechanical behavior of the composites in compression. High-resolution TEM observations at the interface reveal the formation of a thin interdiffusion layer able to provide good bonding between the reinforcing phase and the Al-based matrix. The deformation behavior of the composites was studied, indicating that local plastic deformation occurred in the matrix near the glassy reinforcements followed by the initiation and propagation of cracks mainly through the matrix. The reinforcing phase is seen to inhibit the plastic deformation and retard the crack propagation. The findings offer new insights into the mechanical behavior of metal matrix composites reinforced with metallic glasses. PMID:27067824

  3. Mechanical behavior of Fiber Reinforced SiC/RBSN Ceramic Matrix Composites: Theory and Experiment

    DTIC Science & Technology

    1991-01-01

    AD-A235 926 NASA AVSCOM Technical Memorandum 103688 Technical Report 91-C-004 Mechanical Behavior of Fiber Reinforced SiC/RBSN Ceramic Matrix Composites : Theory... CERAMIC MATRIX COMPOSITES : THEORY AND EXPERIMENT Abhisak Chulya* Department of Civil Engineering Cleveland State University Cleveland, Ohio 44115...tough and sufficiently stable continuous fiber- reinforced ceramic matrix composites (CMC) which can survive in oxidizing environ- ments at temperatures

  4. Behavior of curved laminated composite panels and shells under axial compression

    NASA Astrophysics Data System (ADS)

    Abramovich, H.; Bisagni, C.

    2015-10-01

    The buckling and post-buckling behavior of curved cylindrical stringer-stiffened laminated composite and metal panels had been investigated both numerically and experimentally. The results were compared to those of cylindrical stringer-stiffened laminated composite shells to yield a way of determining the optimal structure to be used for axial compression loading. For the present tested structures, the composite panels showed the best load-weight ratio.

  5. A parameter study on the biaxial behavior of flexible fabric composites

    SciTech Connect

    Mitra, A.; Luo, S.Y.

    1994-12-31

    The nonlinear behavior of flexible fabric composite under large bi-axial deformation is attributed by many factors, including the ratio of biaxial loads, the crimps of the yarns, the thickness of the composite, and the properties of the yarn and the matrix. A parameter study has been conducted to evaluate the significance of these factors on the stress-strain relations of flexible fabric composites.

  6. Effect of egg composition and oxidoreductase on adaptation of Tibetan chicken to high altitude.

    PubMed

    Jia, C L; He, L J; Li, P C; Liu, H Y; Wei, Z H

    2016-07-01

    Tibetan chickens have good adaptation to hypoxic conditions, which can be reflected by higher hatchability than lowland breeds when incubated at high altitude. The objective of this trial was to study changes in egg composition and metabolism with regards the adaptation of Tibetan chickens to high altitude. We measured the dry weight of chicken embryos, egg yolk, and egg albumen, and the activity of lactate dehydrogenase (LDH) and succinic dehydrogenase (SDH) in breast muscle, heart, and liver from embryos of Tibetan chicken and Dwarf chicken (lowland breed) incubated at high (2,900 m) and low (100 m) altitude. We found that growth of chicken embryos was restricted at high altitude, especially for Dwarf chicken embryos. In Tibetan chicken, the egg weight was lighter, but the dry weight of egg yolk was heavier than that of Dwarf chicken. The LDH activities of the three tissues from the high altitude groups were respectively higher than those of the lowland groups from d 15 to hatching, except for breast muscle of Tibetan chicken embryos on d 15. In addition, under the high altitude environment, the heart tissue from Tibetan chicken had lower LDH activity than that from Dwarf chicken at d 15 and 18. The lactic acid content of blood from Tibetan chicken embryos was lower than that of Dwarf chicken at d 12 and 15 of incubation at high altitude. There was no difference in SDH activity in the three tissues between the high altitude groups and the lowland groups except in three tissues of hatchlings and at d 15 of incubation in breast muscle, nor between the two breeds at high altitude except in the heart of hatchlings. Consequently, the adaptation of Tibetan chicken to high altitude may be associated with higher quantities of yolk in the egg and a low metabolic oxygen demand in tissue, which illuminate the reasons that the Tibetan chicken have higher hatchability with lower oxygen transport ability.

  7. Adaptation and Implementation of a Trauma-Focused Cognitive Behavioral Intervention for Girls in Child Welfare.

    PubMed

    Auslander, Wendy; McGinnis, Hollee; Tlapek, Sarah; Smith, Penny; Foster, April; Edmond, Tonya; Dunn, Jerry

    2016-12-15

    This study describes the process of adapting and implementing Girls Aspiring toward Independence (GAIN), a trauma-focused, group-based therapy adapted from Cognitive Behavioral Intervention for Trauma in Schools (CBITS) for girls in child welfare. Descriptive data were examined on 3 outcomes: posttraumatic stress disorder (PTSD), depression, and social problem-solving skills among adolescent girls in the child welfare system. Qualitative and quantitative methods were utilized to inform the adaptation of the CBITS intervention, evaluate feasibility, treatment fidelity, and acceptability, and to test the effects of the intervention. Girls ages 12 to 18 (N = 27) were randomly assigned to the experimental and usual care conditions. Participants' symptoms of PTSD and depression and social problem-solving skills were evaluated at pre, post- (3 months), and follow-up (6 months) assessments. Adaptations for GAIN were primarily related to program structure. Data indicated that the program was receptive to girls in child welfare and that it was feasible to recruit, randomize, assess outcomes, and implement with adequate fidelity. Retention was more successful among younger girls. Descriptive initial data showed greater reductions in the percentage of girls with PTSD and depression, and modest increases in social problem-solving skills in the experimental versus usual care condition. Despite the growth of knowledge in dissemination and implementation research, the application of trauma-focused empirically supported treatment to child welfare populations lags behind. A large-scale RCT is needed to determine if GAIN is effective in reducing mental health problems and social problem-solving in the child welfare population. (PsycINFO Database Record

  8. The Generalizability of Externalizing Behavior Composites and Subscale Scores across Time, Rater, and Instrument

    ERIC Educational Resources Information Center

    Bergeron, Renee; Floyd, Randy G.; McCormack, Allison C.; Farmer, William L.

    2008-01-01

    The dependability of externalizing behavior composites and subscale scores from the Behavior Assessment System for Children, Second Edition, Teacher Rating Scale-Child (Reynolds & Kamphaus, 2004) and the Achenbach System of Empirically Based Assessment, Teacher's Report Form for Ages 6-18 (Achenbach & Rescorla, 2001) was investigated.…

  9. An analysis of the impact of auditory-nerve adaptation on behavioral measures of temporal integration in cochlear implant recipients

    NASA Astrophysics Data System (ADS)

    Hay-McCutcheon, Marcia J.; Brown, Carolyn J.; Abbas, Paul J.

    2005-10-01

    The objective of this study was to determine the impact that auditory-nerve adaptation has on behavioral measures of temporal integration in Nucleus 24 cochlear implant recipients. It was expected that, because the auditory nerve serves as the input to central temporal integrator, a large degree of auditory-nerve adaptation would reduce the amount of temporal integration. Neural adaptation was measured by tracking amplitude changes of the electrically evoked compound action potential (ECAP) in response to 1000-pps biphasic pulse trains of varying durations. Temporal integration was measured at both suprathreshold and threshold levels by an adaptive procedure. Although varying degrees of neural adaptation and temporal integration were observed across individuals, results of this investigation revealed no correlation between the degree of neural adaptation and psychophysical measures of temporal integration.

  10. An analysis of the impact of auditory-nerve adaptation on behavioral measures of temporal integration in cochlear implant recipients.

    PubMed

    Hay-McCutcheon, Marcia J; Brown, Carolyn J; Abbas, Paul J

    2005-10-01

    The objective of this study was to determine the impact that auditory-nerve adaptation has on behavioral measures of temporal integration in Nucleus 24 cochlear implant recipients. It was expected that, because the auditory nerve serves as the input to central temporal integrator, a large degree of auditory-nerve adaptation would reduce the amount of temporal integration. Neural adaptation was measured by tracking amplitude changes of the electrically evoked compound action potential (ECAP) in response to 1000-pps biphasic pulse trains of varying durations. Temporal integration was measured at both suprathreshold and threshold levels by an adaptive procedure. Although varying degrees of neural adaptation and temporal integration were observed across individuals, results of this investigation revealed no correlation between the degree of neural adaptation and psychophysical measures of temporal integration.

  11. The contribution of children's self-regulation and classroom quality to children's adaptive behaviors in the kindergarten classroom.

    PubMed

    Rimm-Kaufman, Sara E; Curby, Tim W; Grimm, Kevin J; Nathanson, Lori; Brock, Laura L

    2009-07-01

    In this study, the authors examined the extent to which children's self-regulation upon kindergarten entrance and classroom quality in kindergarten contributed to children's adaptive classroom behavior. Children's self-regulation was assessed using a direct assessment upon entrance into kindergarten. Classroom quality was measured on the basis of multiple classroom observations during the kindergarten year. Children's adaptive classroom behavior in kindergarten was assessed through teacher report and classroom observations: Teachers rated children's cognitive and behavioral self-control and work habits during the spring of the kindergarten year; observers rated children's engagement and measured off-task behavior at 2-month intervals from November to May. Hierarchical linear models revealed that children's self-regulation upon school entry in a direct assessment related to teachers' report of behavioral self-control, cognitive self-control, and work habits in the spring of the kindergarten year. Classroom quality, particularly teachers' effective classroom management, was linked to children's greater behavioral and cognitive self-control, children's higher behavioral engagement, and less time spent off-task in the classroom. Classroom quality did not moderate the relation between children's self-regulation upon school entry and children's adaptive classroom behaviors in kindergarten. The discussion considers the implications of classroom management for supporting children's early development of behavioral skills that are important in school settings.

  12. The Influence of Temperature on Frictional Behavior of Plasma-Sprayed NiAl-Cr2O3 Based Self-Adaptive Nanocomposite Coatings

    NASA Astrophysics Data System (ADS)

    Ramazani, M.; Ashrafizadeh, F.; Mozaffarinia, R.

    2013-10-01

    Frictional behavior of nano and hybrid-structured NiAl-Cr2O3-Ag-CNT-WS2 adaptive self-lubricant coatings was evaluated at a range of temperatures, from room temperature to 700 °C. For this purpose, hybrid structured (HS) and nanostructured (NS) composite powders with the same nominal compositions were prepared by spray drying and heat treatment techniques. A series of HS and NS coating samples were deposited on steel substrate by an atmospheric plasma spraying process. The tribological behavior of both coatings was studied from room temperature to 700 °C at 100° intervals using a custom designed high temperature wear test machine. Scanning electron microscopy was employed for the evaluation of the composite coatings and worn surfaces. Experimental results indicated that the hybrid coating had inferior tribological properties when compared to the nanostructured coating, showing the attractive frictional behavior on the basis of low friction and high wear resistance; the NS coating possessed a more stable friction coefficient in the temperature range of 25-700 °C against alumina counterface. Microstructural examinations revealed more uniformity in NS plasma-sprayed coatings.

  13. Examining the Specific Effects of Context on Adaptive Behavior and Achievement in a Rural African Community: Six Case Studies from Rural Areas of Southern Province, Zambia

    ERIC Educational Resources Information Center

    Tan, Mei; Reich, Jodi; Hart, Lesley; Thuma, Philip E.; Grigorenko, Elena L.

    2014-01-01

    Generally accepted as universal, the construct of adaptive behavior differs in its manifestations across different cultures and settings. The Vineland-II (Sparrow et al. in "Vineland Adaptive Behavior Scales, Second edn." AGS Publishing, Circle Pines, MN, 2005) was translated into Chitonga and adapted to the setting of rural Southern…

  14. The Treatment of Severe Self-Injurious Behavior by the Systematic Fading of Restraints: Effects of Self-Injury, Self-Restraint, Adaptive Behavior, and Behavioral Correlates of Affect.

    ERIC Educational Resources Information Center

    Oliver, Chris; Hall, Scott; Hales, Jackie; Watts, Derek; Murphy, Glynis

    1998-01-01

    This study examined the effects of introducing flexion into a straight-arm splint, on self-injurious behavior (SIB), self-restraint, adaptive behavior, and behavioral correlates of affect for three individuals with severe mental retardation. For two individuals, SIB was reduced to zero, while overall level of restriction was also significantly…

  15. Experimental investigations on mechanical behavior of aluminium metal matrix composites

    NASA Astrophysics Data System (ADS)

    Rajesh, A. M.; Kaleemulla, Mohammed

    2016-09-01

    Today we are widely using aluminium based metal matrix composite for structural, aerospace, marine and automobile applications for its light weight, high strength and low production cost. The purpose of designing metal matrix composite is to add the desirable attributes of metals and ceramics to the base metal. In this study we developed aluminium metal matrix hybrid composite by reinforced Aluminium7075 alloy with silicon carbide (SiC) and aluminium oxide (alumina) by method of stir casting. This technique is less expensive and very effective. The Hardness test and Wear test were performed on the specimens which are prepared by stir casting techniques. The result reveals that the addition of silicon carbide and alumina particles in aluminium matrix improves the mechanical properties.

  16. Laminated metals composites fracture and ballistic impact behavior

    SciTech Connect

    Lesuer, D.R.; Syn, C.K.; Sherby, O.D.; Wadsworth, J.

    1998-01-20

    Recent advances in the fracture and ballistic impact response of laminated metal composites (LMCs) are reviewed. The laminate structure can provide significant improvements to these properties relative to the component materials. Typical fracture and ballistic impact properties in LMCs are illustrated for systems containing Al alloys and Al matrix composites. The unique mechanisms operating in a layered structure that contribute to fracture or ballistic impact resistance are discussed. The influence of laminate architecture, component material properties and interface strength on mechanisms and properties are briefly reviewed for these Al-based LMCs.

  17. Impact of Resistance Circuit Training on Neuromuscular, Cardiorespiratory and Body Composition Adaptations in the Elderly

    PubMed Central

    Romero-Arenas, Salvador; Martínez-Pascual, Miryam; Alcaraz, Pedro E.

    2013-01-01

    Declines in maximal aerobic power and skeletal muscle force production with advancing age are examples of functional declines with aging, which can severely limit physical performance and independence, and are negatively correlated with all cause mortality. It is well known that both endurance exercise and resistance training can substantially improve physical fitness and health-related factors in older individuals. Circuit-based resistance training, where loads are lifted with minimal rest, may be a very effective strategy for increasing oxygen consumption, pulmonary ventilation, strength, and functional capacity while improving body composition. In addition, circuit training is a time-efficient exercise modality that can elicit demonstrable improvements in health and physical fitness. Hence, it seems reasonable to identify the most effective combination of intensity, volume, work to rest ratio, weekly frequency and exercise sequence to promote neuromuscular, cardiorespiratory and body composition adaptations in the elderly. Thus, the purpose of this review was to summarize and update knowledge about the effects of circuit weight training in older adults and elderly population, as a starting point for developing future interventions that maintain a higher quality of life in people throughout their lifetime. PMID:24124631

  18. Adaptive control of radiated noise from a cylindrical shell using active fiber composite actuators

    NASA Astrophysics Data System (ADS)

    Goddu, Gregory; McDowell, Donald; Bingham, Brian S.

    2000-06-01

    This paper describes the application of Active Fiber Composite (AFC) actuators, a hybrid piezoelectric device, to the reduction of acoustic radiation from a cylindrical shell by active control methods. AFCs were developed to provide a mechanically robust method for large-area, orthotropic actuation and sensing in active structures. The actuation layer is formed by small diameter piezoelectric fibers that are unidirectionally aligned and imbedded in a resin matrix system. By the nature of its structure, an AFC actuator allows use of the primary piezoelectric effect in the plane of the composite. A cylindrical shell testbed is used for this experiment due to the predominance of this structure, and the resulting general interest, within the field of underwater acoustics. To control acoustic radiation from the cylindrical shell, the AFC actuators, placed at optimal locations determined using numerical models, are used to generate a strain field that counteracts the strain associated with acoustically efficient shell motions. Using an end-mounted accelerometer as the error measurement, an adaptive LMS algorithm is used to minimize the error signal in real-time. Experimental are supplied to validate both the device and the methodology in a complex, real-world environment.

  19. Distributed recurrent neural forward models with synaptic adaptation and CPG-based control for complex behaviors of walking robots

    PubMed Central

    Dasgupta, Sakyasingha; Goldschmidt, Dennis; Wörgötter, Florentin; Manoonpong, Poramate

    2015-01-01

    Walking animals, like stick insects, cockroaches or ants, demonstrate a fascinating range of locomotive abilities and complex behaviors. The locomotive behaviors can consist of a variety of walking patterns along with adaptation that allow the animals to deal with changes in environmental conditions, like uneven terrains, gaps, obstacles etc. Biological study has revealed that such complex behaviors are a result of a combination of biomechanics and neural mechanism thus representing the true nature of embodied interactions. While the biomechanics helps maintain flexibility and sustain a variety of movements, the neural mechanisms generate movements while making appropriate predictions crucial for achieving adaptation. Such predictions or planning ahead can be achieved by way of internal models that are grounded in the overall behavior of the animal. Inspired by these findings, we present here, an artificial bio-inspired walking system which effectively combines biomechanics (in terms of the body and leg structures) with the underlying neural mechanisms. The neural mechanisms consist of (1) central pattern generator based control for generating basic rhythmic patterns and coordinated movements, (2) distributed (at each leg) recurrent neural network based adaptive forward models with efference copies as internal models for sensory predictions and instantaneous state estimations, and (3) searching and elevation control for adapting the movement of an individual leg to deal with different environmental conditions. Using simulations we show that this bio-inspired approach with adaptive internal models allows the walking robot to perform complex locomotive behaviors as observed in insects, including walking on undulated terrains, crossing large gaps, leg damage adaptations, as well as climbing over high obstacles. Furthermore, we demonstrate that the newly developed recurrent network based approach to online forward models outperforms the adaptive neuron forward models

  20. Electrical behavior of carbon whisker reinforced elastomer matrix composites

    SciTech Connect

    Chellappa, V.; Chiou, Z.W.; Jang, B.Z.

    1994-12-31

    The electrical and mechanical properties of carbon whisker reinforced thermoplastic elastomer composites were investigated. The reinforcement whisker was made by a catalytic chemical vapor deposition (CCVD) process and the polymer matrix was from a thermoplastic elastomer (TPE, a butadiene-styrene block co-polymer). The electrical resistivity ({rho}) of the CCVD carbon whisker-elastomer composites can be varied by uniaxial deformation (10{sup 1}-10{sup 8}{Omega}-cm) and by changing the temperature (10{sup 1}-10{sup 5}{Omega}-cm). The temperature-resistivity studies indicate, that the resistivity of these composites depend on the physical property of the elastomer. The {rho} vs 1/T curves exhibit two distinct slopes intersected at the T{sub g} of the elastomer (-50{degrees}C). Further uniaxial deformation studies at room temperature (20{degrees}C) demonstrated that the resistivity increased exponentially with the deformation. The dependence of resistivity (or conductivity) of the composites with respect to deformation and temperature was explained on the basis of electron tunnelling induced conduction. CCVD carbon whiskers can be used as a reinforcement (filler) for the elastomer and can also make them electrically conductive.

  1. Oxidation Behavior of Carbon Fiber Reinforced Silicon Carbide Composites

    NASA Technical Reports Server (NTRS)

    Valentin, Victor M.

    1995-01-01

    Carbon fiber reinforced Silicon Carbide (C-SiC) composites offer high strength at high temperatures and good oxidation resistance. However, these composites present some matrix microcracks which allow the path of oxygen to the fiber. The aim of this research was to study the effectiveness of a new Silicon Carbide (SiC) coating developed by DUPONT-LANXIDE to enhance the oxidation resistance of C-SiC composites. A thermogravimetric analysis was used to determine the oxidation rate of the samples at different temperatures and pressures. The Dupont coat proved to be a good protection for the SiC matrix at temperatures lower than 1240 C at low and high pressures. On the other hand, at temperatures above 1340 C the Dupont coat did not seem to give good protection to the composite fiber and matrix. Even though some results of the tests have been discussed, because of time restraints, only a small portion of the desired tests could be completed. Therefore, no major conclusions or results about the effectiveness of the coat are available at this time.

  2. Matched Behavioral and Neural Adaptations for Low Sound Level Echolocation in a Gleaning Bat, Antrozous pallidus

    PubMed Central

    Measor, Kevin R.; Leavell, Brian C.; Brewton, Dustin H.; Rumschlag, Jeffrey; Barber, Jesse R.

    2017-01-01

    Abstract In active sensing, animals make motor adjustments to match sensory inputs to specialized neural circuitry. Here, we describe an active sensing system for sound level processing. The pallid bat uses downward frequency-modulated (FM) sweeps as echolocation calls for general orientation and obstacle avoidance. The bat’s auditory cortex contains a region selective for these FM sweeps (FM sweep-selective region, FMSR). We show that the vast majority of FMSR neurons are sensitive and strongly selective for relatively low levels (30-60 dB SPL). Behavioral testing shows that when a flying bat approaches a target, it reduces output call levels to keep echo levels between ∼30 and 55 dB SPL. Thus, the pallid bat behaviorally matches echo levels to an optimized neural representation of sound levels. FMSR neurons are more selective for sound levels of FM sweeps than tones, suggesting that across-frequency integration enhances level tuning. Level-dependent timing of high-frequency sideband inhibition in the receptive field shapes increased level selectivity for FM sweeps. Together with previous studies, these data indicate that the same receptive field properties shape multiple filters (sweep direction, rate, and level) for FM sweeps, a sound common in multiple vocalizations, including human speech. The matched behavioral and neural adaptations for low-intensity echolocation in the pallid bat will facilitate foraging with reduced probability of acoustic detection by prey. PMID:28275715

  3. Functional regulation of Pb-Ti/MoS2 composite coatings for environmentally adaptive solid lubrication

    NASA Astrophysics Data System (ADS)

    Ren, Siming; Li, Hao; Cui, Mingjun; Wang, Liping; Pu, Jibin

    2017-04-01

    The lubrication of molybdenum disulfide coatings has commonly been limited by the application environments, for instance, the crystal MoS2 are easily affected by water to form MoO3 that causes a higher friction coefficient and short lifetime. Therefore, to improve the tribolgical performance of MoS2 in high humidity condition, the co-doped Pb-Ti/MoS2 composite coatings are deposited by unbalanced magnetron sputtering system. The design of the co-doping elements in MoS2-based coatings can not only maintain the characteristic of low humidity-sensitivity as the Ti/MoS2 coating but also improve the mechanical properties and tribological performance of coatings as a comparison with single-doped ones. Moreover, the ultra-low friction coefficient with a minimum value of 0.006 under the vacuum condition is achieved for Pb-Ti/MoS2 composite coating containing about 4.6 at.% Pb, depending on the densification structure of coating. Intriguingly, the wear behaviours of Pb-Ti/MoS2 composite coatings are in accordance with the variation in H/E (hardness to the elastic modulus) ratio that the coating with higher H/E exhibits lower wear rate. These results demonstrate that the lubricating properties of MoS2 coatings in both humid environment and vacuum condition can be achieved through the Pb and Ti co-doped, which is of great significant for developing MoS2 coatings as the environmentally adaptive lubricants.

  4. Responses of leaf traits to climatic gradients: adaptive variation versus compositional shifts

    NASA Astrophysics Data System (ADS)

    Meng, T.-T.; Wang, H.; Harrison, S. P.; Prentice, I. C.; Ni, J.; Wang, G.

    2015-09-01

    , but Parea increased with temperature. Although the adaptive nature of many of these trait-climate relationships is understood qualitatively, a key challenge for modelling is to predict them quantitatively. Models must take into account that community-level responses to climatic gradients can be influenced by shifts in PFT composition, such as the replacement of deciduous by evergreen trees, which may run either parallel or counter to trait variation within PFTs. The importance of PFT shifts varies among traits, being important for biophysical traits but less so for physiological and chemical traits. Finally, models should take account of the diversity of trait values that is found in all sites and PFTs, representing the "pool" of variation that is locally available for the natural adaptation of ecosystem function to environmental change.

  5. Cultural adaptation of an intervention to reduce sexual risk behaviors among patients attending a STI clinic in St. Petersburg, Russia.

    PubMed

    Grau, Lauretta E; Krasnoselskikh, Tatiana V; Shaboltas, Alla V; Skochilov, Roman V; Kozlov, Andrei P; Abdala, Nadia

    2013-08-01

    Cultural adaptation is an important step in the process of implementing health promotion interventions that, having been proven to be effective in one culture, are being applied in another. This study describes the results of a formative investigation to culturally adapt a STI/HIV risk reduction intervention for use in St. Petersburg, Russia. Analyses of data from brief elicitation interviews, focus groups, community experts, and a pilot test of the adapted intervention identified environmental, cognitive-information processing, and affect-motivation factors that needed to be addressed during the adaptation process. The participant/counselor relationship was adapted to reflect a hierarchical (cf. collaborative) relationship in order to accommodate Russian expectations about patient interactions with healthcare experts. Key skills building activities (e.g., identification of personal risk behaviors, role-playing) were approached gradually or indirectly in order to maintain participants' engagement in the intervention, and close-ended questions were added to assist participants in understanding unfamiliar concepts such as "triggers" and self-efficacy. Information about the prevalence of HIV/STI infections and alcohol use included data specific to St. Petersburg to increase the personal relevance of these materials and messages. Intervention components were tailored to participants' risk reduction and informational needs. No gender differences that would have justified adaptation of the intervention approach or content were noted. Examples of specific adaptations and the key issues to attend to when adapting behavioral interventions for use in Russian clinical settings are discussed.

  6. Ammonia sensing behaviors of TiO2-PANI/PA6 composite nanofibers.

    PubMed

    Wang, Qingqing; Dong, Xianjun; Pang, Zengyuan; Du, Yuanzhi; Xia, Xin; Wei, Qufu; Huang, Fenglin

    2012-12-12

    Titanium dioxide-polyaniline/polyamide 6 (TiO(2)-PANI/PA6) composite nanofibers were prepared by in situ polymerization of aniline in the presence of PA6 nanofibers and a sputtering-deposition process with a high purity titanium sputtering target. TiO(2)-PANI/PA6 composite nanofibers and PANI/PA6 composite nanofibers were fabricated for ammonia gas sensing. The ammonia sensing behaviors of the sensors were examined at room temperature. All the results indicated that the ammonia sensing property of TiO(2)-PANI/PA6 composite nanofibers was superior to that of PANI/PA6 composite nanofibers. TiO(2)-PANI/PA6 composite nanofibers had good selectivity to ammonia. It was also found that the content of TiO(2) had a great influence on both the morphology and the sensing property of TiO(2)-PANI/PA6 composite nanofibers.

  7. A study on the crushing behavior of basalt fiber reinforced composite structures

    NASA Astrophysics Data System (ADS)

    Pandian, A.; Veerasimman, A. P.; Vairavan, M.; Francisco, C.; Sultan, M. T. H.

    2016-10-01

    The crushing behavior and energy absorption capacity of basalt fiber reinforced hollow square structure composites are studied under axial compression. Using the hand layup technique, basalt fiber reinforced composites were fabricated using general purpose (GP) polyester resin with the help of wooden square shaped mould of varying height (100 mm, 150 mm and 200 mm). For comparison, similar specimens of glass fiber reinforced polymer composites were also fabricated and tested. Axial compression load is applied over the top end of the specimen with cross head speed as 2 mm/min using Universal Testing Machine (UTM). From the experimental results, the load-deformation characteristics of both glass fiber and basalt fiber composites were investigated. Crashworthiness and mode of collapse for the composites were determined from load-deformation curve, and they were then compared to each other in terms of their crushing behaviors.

  8. Optimization of Wear Behavior of Magnesium Alloy AZ91 Hybrid Composites Using Taguchi Experimental Design

    NASA Astrophysics Data System (ADS)

    Girish, B. M.; Satish, B. M.; Sarapure, Sadanand; Basawaraj

    2016-06-01

    In the present paper, the statistical investigation on wear behavior of magnesium alloy (AZ91) hybrid metal matrix composites using Taguchi technique has been reported. The composites were reinforced with SiC and graphite particles of average size 37 μm. The specimens were processed by stir casting route. Dry sliding wear of the hybrid composites were tested on a pin-on-disk tribometer under dry conditions at different normal loads (20, 40, and 60 N), sliding speeds (1.047, 1.57, and 2.09 m/s), and composition (1, 2, and 3 wt pct of each of SiC and graphite). The design of experiments approach using Taguchi technique was employed to statistically analyze the wear behavior of hybrid composites. Signal-to-noise ratio and analysis of variance were used to investigate the influence of the parameters on the wear rate.

  9. Simplifications in the Behavior of Viscoelastic Composites With Growing Damage

    DTIC Science & Technology

    1990-07-01

    Eengineering interest. The emphasis of this paper is on simplifications which appear to be applicable at least to particle and fiber reinforced polymers when the...parameters. From equation (5), 3 Qj= aW T/aq j (10) showing that the body exhibits hyperelastic behavior during the time any 3 particular set of

  10. Compression Behavior of Fluted-Core Composite Panels

    NASA Technical Reports Server (NTRS)

    Schultz, Marc R.; Oremont, Leonard; Guzman, J. Carlos; McCarville, Douglas; Rose, Cheryl A.; Hilburger, Mark W.

    2011-01-01

    In recent years, fiber-reinforced composites have become more accepted for aerospace applications. Specifically, during NASA s recent efforts to develop new launch vehicles, composite materials were considered and baselined for a number of structures. Because of mass and stiffness requirements, sandwich composites are often selected for many applications. However, there are a number of manufacturing and in-service concerns associated with traditional honeycomb-core sandwich composites that in certain instances may be alleviated through the use of other core materials or construction methods. Fluted-core, which consists of integral angled web members with structural radius fillers spaced between laminate face sheets, is one such construction alternative and is considered herein. Two different fluted-core designs were considered: a subscale design and a full-scale design sized for a heavy-lift-launch-vehicle interstage. In particular, axial compression of fluted-core composites was evaluated with experiments and finite-element analyses (FEA); axial compression is the primary loading condition in dry launch-vehicle barrel sections. Detailed finite-element models were developed to represent all components of the fluted-core construction, and geometrically nonlinear analyses were conducted to predict both buckling and material failures. Good agreement was obtained between test data and analyses, for both local buckling and ultimate material failure. Though the local buckling events are not catastrophic, the resulting deformations contribute to material failures. Consequently, an important observation is that the material failure loads and modes would not be captured by either linear analyses or nonlinear smeared-shell analyses. Compression-after-impact (CAI) performance of fluted core composites was also investigated by experimentally testing samples impacted with 6 ft.-lb. impact energies. It was found that such impacts reduced the ultimate load carrying capability by

  11. Analytical and numerical modeling of the mechanical behavior of metal matrix composites

    NASA Astrophysics Data System (ADS)

    Elfishawy, Karim Fouad

    Metal matrix composites (MMCs) subjected to both external and thermal cycling loading can experience enhanced creep deformation, leading to dimensional instability in some cases. Three-dimensional finite element models have been constructed to predict the behavior of composites under such loading conditions. The different possible types of composite behavior are discussed in detail. The language and ideas developed in the continuum mechanics area of ratcheting and shakedown was shown to correlate quite closely to the thermal cycling behavior of composites and to apply to their analysis and design. Three composite configurations were analyzed analytically and their models were used to construct Composite Behavior Maps (CBMs). CBMs are diagrams which delineate regions of dimensionally stable and unstable composite behavior, and were shown to have a characteristic shape. Experimental and analytical methods are outlined for constructing conservative CBMs for complex composite configurations for which analytical solutions are not possible. The utility of such diagrams as both an analysis and design tool for MMCs on the microstructural scale is discussed in detail. The fundamental elastic and plastic properties of a new non-traditional alumina/aluminum composite where both phases are continuous, known as Csp4, were investigated analytically using finite element simulations and compared to experimental results. The composite behaves in a nearly bilinear manner defined by an elastic modulus and an elastic-plastic modulus. The apparent plasticity in the composite was shown to occur by true plastic deformation of aluminum and elastic accommodation of alumina. Effects of residual stresses and matrix strength on the tensile and compressive behavior of the composite were also investigated. The concept of selective reinforcement is discussed, along with its special considerations and limitations. The applicability and effectiveness of selective reinforcement as a design approach

  12. Oxidation behavior of molybdenum silicides and their composites

    SciTech Connect

    Natesan, K.; Deevi, S. C.

    2000-04-03

    A key materials issue associated with the future of high-temperature structural silicides is the resistance of these materials to oxidation at low temperatures. Oxidation tests were conducted on Mo-based silicides over a wide temperature range to evaluate the effects of alloy composition and temperature on the protective scaling characteristics and testing regime for the materials. The study included Mo{sub 5}Si{sub 3} alloys that contained several concentrations of B. In addition, oxidation characteristics of MoSi{sub 2}-Si{sub 3}N{sub 4} composites that contained 20--80 vol.% Si{sub 3}N{sub 4} were evaluated at 500--1,400 C.

  13. Behavioral buffering of global warming in a cold-adapted lizard.

    PubMed

    Ortega, Zaida; Mencía, Abraham; Pérez-Mellado, Valentín

    2016-07-01

    Alpine lizards living in restricted areas might be particularly sensitive to climate change. We studied thermal biology of Iberolacerta cyreni in high mountains of central Spain. Our results suggest that I. cyreni is a cold-adapted thermal specialist and an effective thermoregulator. Among ectotherms, thermal specialists are more threatened by global warming than generalists. Alpine lizards have no chance to disperse to new suitable habitats. In addition, physiological plasticity is unlikely to keep pace with the expected rates of environmental warming. Thus, lizards might rely on their behavior in order to deal with ongoing climate warming. Plasticity of thermoregulatory behavior has been proposed to buffer the rise of environmental temperatures. Therefore, we studied the change in body and environmental temperatures, as well as their relationships, for I. cyreni between the 1980s and 2012. Air temperatures have increased more than 3.5°C and substrate temperatures have increased by 6°C in the habitat of I. cyreni over the last 25 years. However, body temperatures of lizards have increased less than 2°C in the same period, and the linear relationship between body and environmental temperatures remains similar. These results show that alpine lizards are buffering the potential impact of the increase in their environmental temperatures, most probably by means of their behavior. Body temperatures of I. cyreni are still cold enough to avoid any drop in fitness. Nonetheless, if warming continues, behavioral buffering might eventually become useless, as it would imply spending too much time in shelter, losing feeding, and mating opportunities. Eventually, if body temperature exceeds the thermal optimum in the near future, fitness would decrease abruptly.

  14. Adaptation and implementation of cognitive behavioral intervention for trauma in schools with American Indian youth.

    PubMed

    Goodkind, Jessica R; Lanoue, Marianna D; Milford, Jaime

    2010-01-01

    American Indian adolescents experience higher rates of suicide and psychological distress than the overall U.S. adolescent population, and research suggests that these disparities are related to higher rates of violence and trauma exposure. Despite elevated risk, there is limited empirical information to guide culturally appropriate treatment of trauma and related symptoms. We report a pilot study of an adaptation to the Cognitive Behavioral Intervention for Trauma in Schools in a sample of 24 American Indian adolescents. Participants experienced significant decreases in anxiety and posttraumatic stress disorder symptoms, and avoidant coping strategies, as well as a marginally significant decrease in depression symptoms. Improvements in anxiety and depression were maintained 6 months postintervention; improvements in posttraumatic stress disorder and avoidant coping strategies were not.

  15. Adaptation and Implementation of Cognitive Behavioral Intervention for Trauma in Schools with American Indian Youth

    PubMed Central

    Goodkind, Jessica R.; LaNoue, Marianna D.; Milford, Jaime

    2011-01-01

    American Indian (AI) adolescents experience higher rates of suicide and psychological distress than the overall U.S. adolescent population, and research suggests that these disparities are related to higher rates of violence and trauma exposure. Despite elevated risk, there is limited empirical information to guide culturally appropriate treatment of trauma and related symptoms. We report a pilot study of an adaptation to the Cognitive Behavioral Intervention for Trauma in Schools in a sample of 24 AI adolescents. Participants experienced significant decreases in anxiety and PTSD symptoms, and avoidant coping strategies, as well as a marginally significant decrease in depression symptoms. Improvements in anxiety and depression were maintained 6 months post-intervention; improvements in PTSD and avoidant coping strategies were not. Feasibility, appropriateness, and acceptability of CBITS are discussed in the context of efforts to develop culturally sensitive interventions for AI youth. PMID:21058132

  16. Numerical Relations and Skill Level Constrain Co-Adaptive Behaviors of Agents in Sports Teams

    PubMed Central

    Silva, Pedro; Travassos, Bruno; Vilar, Luís; Aguiar, Paulo; Davids, Keith; Araújo, Duarte; Garganta, Júlio

    2014-01-01

    Similar to other complex systems in nature (e.g., a hunting pack, flocks of birds), sports teams have been modeled as social neurobiological systems in which interpersonal coordination tendencies of agents underpin team swarming behaviors. Swarming is seen as the result of agent co-adaptation to ecological constraints of performance environments by collectively perceiving specific possibilities for action (affordances for self and shared affordances). A major principle of invasion team sports assumed to promote effective performance is to outnumber the opposition (creation of numerical overloads) during different performance phases (attack and defense) in spatial regions adjacent to the ball. Such performance principles are assimilated by system agents through manipulation of numerical relations between teams during training in order to create artificially asymmetrical performance contexts to simulate overloaded and underloaded situations. Here we evaluated effects of different numerical relations differentiated by agent skill level, examining emergent inter-individual, intra- and inter-team coordination. Groups of association football players (national – NLP and regional-level – RLP) participated in small-sided and conditioned games in which numerical relations between system agents were manipulated (5v5, 5v4 and 5v3). Typical grouping tendencies in sports teams (major ranges, stretch indices, distances of team centers to goals and distances between the teams' opposing line-forces in specific team sectors) were recorded by plotting positional coordinates of individual agents through continuous GPS tracking. Results showed that creation of numerical asymmetries during training constrained agents' individual dominant regions, the underloaded teams' compactness and each team's relative position on-field, as well as distances between specific team sectors. We also observed how skill level impacted individual and team coordination tendencies. Data revealed

  17. Numerical relations and skill level constrain co-adaptive behaviors of agents in sports teams.

    PubMed

    Silva, Pedro; Travassos, Bruno; Vilar, Luís; Aguiar, Paulo; Davids, Keith; Araújo, Duarte; Garganta, Júlio

    2014-01-01

    Similar to other complex systems in nature (e.g., a hunting pack, flocks of birds), sports teams have been modeled as social neurobiological systems in which interpersonal coordination tendencies of agents underpin team swarming behaviors. Swarming is seen as the result of agent co-adaptation to ecological constraints of performance environments by collectively perceiving specific possibilities for action (affordances for self and shared affordances). A major principle of invasion team sports assumed to promote effective performance is to outnumber the opposition (creation of numerical overloads) during different performance phases (attack and defense) in spatial regions adjacent to the ball. Such performance principles are assimilated by system agents through manipulation of numerical relations between teams during training in order to create artificially asymmetrical performance contexts to simulate overloaded and underloaded situations. Here we evaluated effects of different numerical relations differentiated by agent skill level, examining emergent inter-individual, intra- and inter-team coordination. Groups of association football players (national--NLP and regional-level--RLP) participated in small-sided and conditioned games in which numerical relations between system agents were manipulated (5v5, 5v4 and 5v3). Typical grouping tendencies in sports teams (major ranges, stretch indices, distances of team centers to goals and distances between the teams' opposing line-forces in specific team sectors) were recorded by plotting positional coordinates of individual agents through continuous GPS tracking. Results showed that creation of numerical asymmetries during training constrained agents' individual dominant regions, the underloaded teams' compactness and each team's relative position on-field, as well as distances between specific team sectors. We also observed how skill level impacted individual and team coordination tendencies. Data revealed emergence of

  18. Adaptive pattern of nectar volume within inflorescences: bumblebee foraging behavior and pollinator-mediated natural selection

    PubMed Central

    Zhao, Zhigang; Lu, Ningna; Conner, Jeffrey K.

    2016-01-01

    Larger floral displays increase pollinator visitation as well as among-flower self-pollination (geitonogamy) in self-compatible species. Dichogamy (temporal separation of gender expression) can limit geitonogamy and increase outcrossing but this depends on pollinator behavior within inflorescences. Declining nectar volume from lower to upper flowers is a hypothesized adaptation to increase outcrossing and pollen export by encouraging the upward movment of pollinators from female to male flowers and by reducing the number of flowers probed per inflorescence, but supporting evidence has been equivocal. We tested this hypothesis in Aconitum gymnandrum by studying floral display and rewards, pollinator visitation, and pollinator-mediated selection on floral traits. We found that larger inflorescences of A. gymnandrum attracted more pollinators, but did not increase the number of flowers probed per visit. Nectar production declined with increasing flower height on average, but the opposite pattern was also common. Bumblebees responded strongly to the nectar pattern, moving from higher to lower nectar concentration. Finally, there was significant pollinator-mediated direct selection for this pattern of declining nectar volume after correcting for correlations with flower size, number, and mean nectar volume. Together, the results strongly suggest that declining nectar production in higher flowers is an adaptation to enhance outcrossing in A. gymnandrum. PMID:27687244

  19. Antenatal Glucocorticoid Treatment Induces Adaptations in Adult Midbrain Dopamine Neurons, which Underpin Sexually Dimorphic Behavioral Resilience

    PubMed Central

    Virdee, Kanwar; McArthur, Simon; Brischoux, Frédéric; Caprioli, Daniele; Ungless, Mark A; Robbins, Trevor W; Dalley, Jeffrey W; Gillies, Glenda E

    2014-01-01

    We demonstrated previously that antenatal glucocorticoid treatment (AGT, gestational days 16–19) altered the size and organization of the adult rat midbrain dopaminergic (DA) populations. Here we investigated the consequences of these AGT-induced cytoarchitectural disturbances on indices of DA function in adult rats. We show that in adulthood, enrichment of striatal DA fiber density paralleled AGT-induced increases in the numbers of midbrain DA neurons, which retained normal basal electrophysiological properties. This was co-incident with changes in (i) striatal D2-type receptor levels (increased, both sexes); (ii) D1-type receptor levels (males decreased; females increased); (iii) DA transporter levels (males increased; females decreased) in striatal regions; and (iv) amphetamine-induced mesolimbic DA release (males increased; females decreased). However, despite these profound, sexually dimorphic changes in markers of DA neurotransmission, in-utero glucocorticoid overexposure had a modest or no effect on a range of conditioned and unconditioned appetitive behaviors known to depend on mesolimbic DA activity. These findings provide empirical evidence for enduring AGT-induced adaptive mechanisms within the midbrain DA circuitry, which preserve some, but not all, functions, thereby casting further light on the vulnerability of these systems to environmental perturbations. Furthermore, they demonstrate these effects are achieved by different, often opponent, adaptive mechanisms in males and females, with translational implications for sex biases commonly found in midbrain DA-associated disorders. PMID:23929547

  20. Cognitions as determinants of (mal)adaptive emotions and emotionally intelligent behavior in an organizational context.

    PubMed

    Spörrle, Matthias; Welpe, Isabell M; Försterling, Friedrich

    2006-01-01

    This study applies the theoretical concepts of Rational Emotive Behavior Therapy (REBT; Ellis, 1962, 1994) to the analysis of functional and dysfunctional behaviour and emotions in the workplace and tests central assumptions of REBT in an organizational setting. We argue that Ellis' appraisal theory of emotion sheds light on some of the cognitive and emotional antecedents of emotional intelligence and emotionally intelligent behaviour. In an extension of REBT, we posit that adaptive emotions resulting from rational cognitions reflect more emotional intelligence than maladaptive emotions which result from irrational cognitions, because the former lead to functional behaviour. We hypothesize that semantically similar emotions (e.g. annoyance and rage) lead to different behavioural reactions and have a different functionality in an organizational context. The results of scenario experiments using organizational vignettes confirm the central assumptions of Ellis' appraisal theory and support our hypotheses of a correspondence between adaptive emotions and emotionally intelligent behaviour. Additionally, we find evidence that irrational job-related attitudes result in reduced work (but not life) satisfaction.

  1. Cognitive Adaptations for n-person Exchange: The Evolutionary Roots of Organizational Behavior

    PubMed Central

    Tooby, John; Cosmides, Leda; Price, Michael E.

    2013-01-01

    Organizations are composed of stable, predominantly cooperative interactions or n-person exchanges. Humans have been engaging in n-person exchanges for a great enough period of evolutionary time that we appear to have evolved a distinct constellation of species-typical mechanisms specialized to solve the adaptive problems posed by this form of social interaction. These mechanisms appear to have been evolutionarily elaborated out of the cognitive infrastructure that initially evolved for dyadic exchange. Key adaptive problems that these mechanisms are designed to solve include coordination among individuals, and defense against exploitation by free riders. Multi-individual cooperation could not have been maintained over evolutionary time if free riders reliably benefited more than contributors to collective enterprises, and so outcompeted them. As a result, humans evolved mechanisms that implement an aversion to exploitation by free riding, and a strategy of conditional cooperation, supplemented by punitive sentiment towards free riders. Because of the design of these mechanisms, how free riding is treated is a central determinant of the survival and health of cooperative organizations. The mapping of the evolved psychology of n-party exchange cooperation may contribute to the construction of a principled theoretical foundation for the understanding of human behavior in organizations. PMID:23814325

  2. Investigations into the mechanical behavior of composite bolted joints

    NASA Technical Reports Server (NTRS)

    Perry, J. C.; Hyer, M. W.

    1979-01-01

    Testing procedures and data reduction and interpretation techniques were established for a program to study the mechanical behavior of bolted joints at room temperature, -157 C (-250 F), and 315 C (600 F). The load transfer characteristics, from one bolt to another, in double-bolt joints were investigated by examining data generated in previous investigations. From the results, it appears the increase in load-carrying capacity by adding a second bolt in tandem can be predicted.

  3. Investigations into the mechanical behavior of composite bolted joints

    NASA Technical Reports Server (NTRS)

    Thornton, E. A.; Perry, J. C.; Hyer, M. W.

    1979-01-01

    Testing procedures, data reduction, and data interpretation methods used to study the mechanical behavior of graphite-polyimide bolted joints at room temperature, -157 C (-250 F), and 315 C (600 F) are described. The load transfer characteristics, from one bolt to another, in double-bolt joints were determined by examining data generated in previous investigations. From the results, it appears the increase in load-carrying capacity by adding a second bolt in tandem can be predicted.

  4. Sphingomyelin interfacial behavior: the impact of changing acyl chain composition.

    PubMed Central

    Li, X M; Smaby, J M; Momsen, M M; Brockman, H L; Brown, R E

    2000-01-01

    Sphingomyelins (SMs) containing homogeneous acyl chains with 12, 14, 16, 18, 24, or 26 carbons were synthesized and characterized using an automated Langmuir-type film balance. Surface pressure was monitored as a function of lipid molecular area at constant temperatures between 10 degrees C and 30 degrees C. SM containing lauroyl (12:0) acyl chains displayed only liquid-expanded behavior. Increasing the length of the saturated acyl chain (e.g., 14:0, 16:0, or 18:0) resulted in liquid-expanded to condensed two-dimensional phase transitions at many temperatures in the 10-30 degrees C range. Similar behavior was observed for SMs with lignoceroyl (24:0) or (cerotoyl) 26:0 acyl chains, but isotherms showed only condensed behavior at 10 and 15 degrees C. Insights into the physico-mechanical in-plane interactions occurring within the different SM phases and accompanying changes in SM phase state were provided by analyzing the interfacial area compressibility moduli. At similar surface pressures, SM fluid phases were less compressible than those of phosphatidylcholines with similar chain structures. The area per molecule and compressibility of SM condensed phases depended upon the length of the saturated acyl chain and upon spreading temperature. Spreading of SMs with very long saturated acyl chains at temperatures 30-35 degrees below T(m) resulted in condensed films with lower in-plane compressibilities, but consistently larger cross-sectional molecular areas than the condensed phases achieved by spreading at temperatures only 10-20 degrees below T(m). This behavior is discussed in terms of the enhancement of SM lateral aggregation by temperature reduction, a common approach used during domain isolation from biomembranes. PMID:10733971

  5. Manufacture and experimental and theoretical evaluation of adaptative glass/epoxy composites with embedded shape memory alloy wires

    NASA Astrophysics Data System (ADS)

    Choi, Young-Kuk; Salvia, Michelle

    2001-07-01

    Adaptable hybrid composites are materials into which actuators are embedded in polymer matrix composites. Shape memory alloys (SMA) are amongst the potential candidates for actuators embedded in such composite smart structures. In order to test the influence of the processing conditions on the actuation properties of adaptive hybrid composites, a model system based on a glass epoxy asymmetric laminate composite with prestrained shape memory nitinol-copper wires, was used. When the SMA wires were electrically heated and cooled, undergoing a reversible martensite to austenite transformation, reversible bending of the host composite was observed. The most important deflection of the host composite was obtained for the material, processed with embedded wires in TWSME conditions. Nevertheless, for samples just prestrained for the OWSME, a self-training effect occurred in relation to the reverse polarized austenite to martensite transformation, during cooling after actuation. The experimental results obtained in the conditions of the sample processed with embedded wires in TWSME conditions can be modeled in the frame of recent phenomenological modeling. In spite of some drastic simplifications, the quasi-linear variation of the bending effect with temperature is correctly described using the metallurgical parameters defined from the Clausius-Clapeyron diagrams of this alloy previously determined.

  6. A study of an adaptive replication framework for orchestrated composite web services.

    PubMed

    Mohamed, Marwa F; Elyamany, Hany F; Nassar, Hamed M

    2013-01-01

    Replication is considered one of the most important techniques to improve the Quality of Services (QoS) of published Web Services. It has achieved impressive success in managing resource sharing and usage in order to moderate the energy consumed in IT environments. For a robust and successful replication process, attention should be paid to suitable time as well as the constraints and capabilities in which the process runs. The replication process is time-consuming since outsourcing some new replicas into other hosts is lengthy. Furthermore, nowadays, most of the business processes that might be implemented over the Web are composed of multiple Web services working together in two main styles: Orchestration and Choreography. Accomplishing a replication over such business processes is another challenge due to the complexity and flexibility involved. In this paper, we present an adaptive replication framework for regular and orchestrated composite Web services. The suggested framework includes a number of components for detecting unexpected and unhappy events that might occur when consuming the original published web services including failure or overloading. It also includes a specific replication controller to manage the replication process and select the best host that would encapsulate a new replica. In addition, it includes a component for predicting the incoming load in order to decrease the time needed for outsourcing new replicas, enhancing the performance greatly. A simulation environment has been created to measure the performance of the suggested framework. The results indicate that adaptive replication with prediction scenario is the best option for enhancing the performance of the replication process in an online business environment.

  7. Composite adaptive control of belt polishing force for aero-engine blade

    NASA Astrophysics Data System (ADS)

    Zhsao, Pengbing; Shi, Yaoyao

    2013-09-01

    The existing methods for blade polishing mainly focus on robot polishing and manual grinding. Due to the difficulty in high-precision control of the polishing force, the blade surface precision is very low in robot polishing, in particular, quality of the inlet and exhaust edges can not satisfy the processing requirements. Manual grinding has low efficiency, high labor intensity and unstable processing quality, moreover, the polished surface is vulnerable to burn, and the surface precision and integrity are difficult to ensure. In order to further improve the profile accuracy and surface quality, a pneumatic flexible polishing force-exerting mechanism is designed and a dual-mode switching composite adaptive control(DSCAC) strategy is proposed, which combines Bang-Bang control and model reference adaptive control based on fuzzy neural network(MRACFNN) together. By the mode decision-making mechanism, Bang-Bang control is used to track the control command signal quickly when the actual polishing force is far away from the target value, and MRACFNN is utilized in smaller error ranges to improve the system robustness and control precision. Based on the mathematical model of the force-exerting mechanism, simulation analysis is implemented on DSCAC. Simulation results show that the output polishing force can better track the given signal. Finally, the blade polishing experiments are carried out on the designed polishing equipment. Experimental results show that DSCAC can effectively mitigate the influence of gas compressibility, valve dead-time effect, valve nonlinear flow, cylinder friction, measurement noise and other interference on the control precision of polishing force, which has high control precision, strong robustness, strong anti-interference ability and other advantages compared with MRACFNN. The proposed research achieves high-precision control of the polishing force, effectively improves the blade machining precision and surface consistency, and

  8. Functional adaptation of long bone extremities involves the localized ``tuning'' of the cortical bone composition; evidence from Raman spectroscopy

    NASA Astrophysics Data System (ADS)

    Buckley, Kevin; Kerns, Jemma G.; Birch, Helen L.; Gikas, Panagiotis D.; Parker, Anthony W.; Matousek, Pavel; Goodship, Allen E.

    2014-11-01

    In long bones, the functional adaptation of shape and structure occurs along the whole length of the organ. This study explores the hypothesis that adaptation of bone composition is also site-specific and that the mineral-to-collagen ratio of bone (and, thus, its mechanical properties) varies along the organ's length. Raman spectroscopy was used to map the chemical composition of long bones along their entire length in fine spatial resolution (1 mm), and then biochemical analysis was used to measure the mineral, collagen, water, and sulfated glycosaminoglycan content where site-specific differences were seen. The results show that the mineral-to-collagen ratio of the bone material in human tibiae varies by <5% along the mid-shaft but decreases by >10% toward the flared extremities of the bone. Comparisons with long bones from other large animals (horses, sheep, and deer) gave similar results with bone material composition changing across tens of centimeters. The composition of the bone apatite also varied with the phosphate-to-carbonate ratio decreasing toward the ends of the tibia. The data highlight the complexity of adaptive changes and raise interesting questions about the biochemical control mechanisms involved. In addition to their biological interest, the data provide timely information to researchers developing Raman spectroscopy as a noninvasive tool for measuring bone composition in vivo (particularly with regard to sampling and measurement protocol).

  9. Wear behavior of light-cured resin composites with bimodal silica nanostructures as fillers.

    PubMed

    Wang, Ruili; Bao, Shuang; Liu, Fengwei; Jiang, Xiaoze; Zhang, Qinghong; Sun, Bin; Zhu, Meifang

    2013-12-01

    To enhance wear behavior of resin composites, bimodal silica nanostructures including silica nanoparticles and silica nanoclusters were prepared and proposed as fillers. The silica nanoclusters, a combination of individually dispersed silica nanoparticles and their agglomerations, with size distribution of 0.07-2.70 μm, were fabricated by the coupling reaction between amino and epoxy functionalized silica nanoparticles, which were obtained by the surface modification of silica nanoparticles (~70 nm) using 3-aminopropyl triethoxysilane (APTES) and 3-glycidoxypropyl trimethoxysilane (GPS) as coupling agents, respectively. Silica nanoparticles and nanoclusters were then silanized with 3-methacryloxypropyl trimethoxysilane (γ-MPS) to prepare composites by mixing with bisphenol A glycerolate dimethacrylate (Bis-GMA) and tri (ethylene glycol) dimethacrylate (TEGDMA). Experimental composites with various filler compositions were prepared and their wear behaviors were assessed in this work. The results suggested that composites with increasing addition of silica nanoparticles in co-fillers possessed lower wear volume and smoother worn surface. Particularly, the composite 53:17 with the optimum weight ratio of silica nanoparticles and silica nanoclusters presented the excellent wear behavior with respect to that of the commercial Esthet-X, although the smallest wear volume was achieved by Z350 XT. The introduction of bimodal silica nanostructures as fillers might provide a new sight for the design of resin composites with significantly improved wear resistance.

  10. Effect of Sericin on Mechanical Behavior of Composite Material Reinforced by Silk Woven Fabric

    NASA Astrophysics Data System (ADS)

    Kimura, Teruo; Ino, Haruhiro; Hanada, Koji; Katori, Sigetaka

    Recent, attention has been given to shift from glass fibers and carbon fibers to natural fibers for FRP composites for the goal of protecting the environment. This paper concerned with the application of silk fabric for composite materials. Polypropylene (PP) was used for the matrix material and the silk fabric composites were molded using a compression molding method. Especially, the effect of sericin on mechanical behaviors of composite materials was discussed. Good adhesion between silk and PP was obtained by removing the sericin existing around the fibroin. The tensile modulus of composite decreased with decreasing the sericin because of the flexibility of silk fibers without sericin. In particular, the higher Izod impact value was obtained for the composites containing the silk fibers without sericin.

  11. Mechanical behavior of glass fiber polyester hybrid composite filled with natural fillers

    NASA Astrophysics Data System (ADS)

    Gupta, G.; Gupta, A.; Dhanola, A.; Raturi, A.

    2016-09-01

    Now-a-days, the natural fibers and fillers from renewable natural resources offer the potential to act as a reinforcing material for polymer composite material alternative to the use of synthetic fiber like as; glass, carbon and other man-made fibers. Among various natural fibers and fillers like banana, wheat straw, rice husk, wood powder, sisal, jute, hemp etc. are the most widely used natural fibers and fillers due to its advantages like easy availability, low density, low production cost and reasonable physical and mechanical properties This research work presents the effect of natural fillers loading with 5%, 10% and 15% on mechanical behavior of polyester based hybrid composites. The result of test depicted that hybrid composite has far better properties than single fibre glass reinforced composite under impact and flexural loads. However it is found that the hybrid composite have better strength as compared to single glass fibre composites.

  12. The experimental behavior of spinning pretwisted laminated composite plates

    NASA Technical Reports Server (NTRS)

    Kosmatka, John B.; Lapid, Alex J.

    1993-01-01

    The purpose of the research is to gain an understanding of the material and geometric couplings present in advanced composite turbo-propellers. Twelve pre-twisted laminated composite plates are tested. Three different ply lay-ups (2 symmetric and 1 asymmetric) and four different geometries (flat and 30x pre-twist about the mid-chord, quarter-chord, and leading edge) distinguish each plate from one another. Four rotating and non-rotating tests are employed to isolate the material and geometric couplings of an advanced turbo propeller. The first series of tests consist of non-rotating static displacement, strain, and vibrations. These tests examine the effects of ply lay-up and geometry. The second series of tests consist of rotating displacement, strain, and vibrations with various pitch and sweep settings. These tests utilize the Dynamic Spin Rig Facility at the NASA Lewis Research Center. The rig allows the spin testing of the plates in a near vacuum environment. The tests examine how the material and plate geometry interact with the pitch and sweep geometry of an advanced turbo-propeller.

  13. Mechanical Behavior of Electrospun Palmfruit Bunch Reinforced Polylactide Composite Fibers

    NASA Astrophysics Data System (ADS)

    Adeosun, S. O.; Akpan, E. I.; Gbenebor, O. P.; Peter, A. A.; Olaleye, Samuel Adebayo

    2016-01-01

    In this study, the mechanical characteristics of electrospun palm fruit bunch reinforced poly lactic acid (PLA) nanofiber composites using treated and untreated filler was examined. Poly lactic acid-palm fruit bunch-dichloromethane blends were electrospun by varying the concentration of the palm fruit bunch between 0 wt.% and 8 wt.%. A constant voltage of 26 kV was applied, the tip-to-collector distance was maintained at 27.5 cm and PLA-palm fruit bunch-dichloromethane (DCM) concentration of 12.5% (w/v) was used. The results revealed that the presence of untreated palm fruit bunch fillers in the electrospun PLA matrix significantly reduces the average diameters of the fibers, causing the formation of beads. As a result there are reductions in tensile strengths of the fibers. The presence of treated palm fruit bunch fillers in the electrospun PLA matrix increases the average diameters of the fibers with improvements in the mechanical properties. The optimal mechanical responses were obtained at 3 wt.% of the treated palm fruit bunch fillers in the PLA matrix. However, increase in the palm fruit fillers (treated and untreated) in the PLA matrix promoted the formation of beads in the nanofiber composites.

  14. Sex-based differences in the adaptive value of social behavior contrasted against morphology and environment.

    PubMed

    Vander Wal, E; Festa-Bianchet, M; Réale, D; Coltman, D W; Pelletier, F

    2015-03-01

    The adaptive nature of sociality has long been a central question in ecology and evolution. However, the relative importance of social behavior for fitness, compared to morphology and environment, remains largely unknown. We assessed the importance of sociality for fitness (lamb production and survival) in a population of mark6d bighorn sheep (Ovis canadensis) over 16 years (n = 1022 sheep-years). We constructed social networks from observations (n = 38,350) of group membership (n = 3150 groups). We then tested whether consistent individual differences in social behavior (centrality) exist and evaluated their relative importance compared to factors known to affect fitness: mass, age, parental effects, and population density. Sheep exhibited consistent individual differences in social centrality. Controlling for maternal carryover effects and age, the positive effect of centrality in a social network on adult female lamb production and survival was equal or greater than the effect of body mass or population density. Social centrality had less effect on male survival and no effect on adult male lamb production or lamb survival. Through its effect on lamb production and survival, sociality in fission-fusion animal societies may ultimately influence population dynamics equally or more than morphological or environmental effects.

  15. Time-dependent deformation behavior of polyvinylidene fluoride binder: Implications on the mechanics of composite electrodes

    NASA Astrophysics Data System (ADS)

    Santimetaneedol, Arnuparp; Tripuraneni, Rajasekhar; Chester, Shawn A.; Nadimpalli, Siva P. V.

    2016-11-01

    The majority of existing battery models that simulate composite electrode behavior assume the binder as a linear elastic material due to lack of a thorough understanding of time-dependent mechanical behavior of binders. Here, thin films of polyvinylidene fluoride binder, prepared according to commercial battery manufacturing method, are subjected to standard monotonic, load-unload, and relaxation tests to characterize the time-dependent mechanical behavior. The strain in the binder samples is measured with the digital image correlation technique to eliminate experimental errors. The experimental data showed that for (charging/discharging) time scales of practical importance, polyvinylidene fluoride behaves more like an elastic-viscoplastic material as opposed to a visco-elastic material; based on this observation, a simple elastic-viscoplastic model, calibrated against the data is adopted to represent the deformation behavior of binder in a Si-based composite electrode; the lithiation/delithiation process of this composite was simulated at different C rates and the stress/strain behavior was monitored. It is observed that the linear elastic assumption of the binder leads to inaccurate results and the time-dependent constitutive behavior of the binder not only leads to accurate prediction of the mechanics but is an essential step towards developing advanced multi-physics models for simulating the degradation behavior of batteries.

  16. Frontostriatal and behavioral adaptations to daily sugar-sweetened beverage intake: a randomized controlled trial.

    PubMed

    Burger, Kyle S

    2017-03-01

    Background: Current obesity theories suggest that the repeated intake of highly palatable high-sugar foods causes adaptions in the striatum, parietal lobe, and prefrontal and visual cortices in the brain that may serve to perpetuate consumption in a feed-forward manner. However, the data for humans are cross-sectional and observational, leaving little ability to determine the temporal precedence of repeated consumption on brain response.Objective: We tested the impact of regular sugar-sweetened beverage intake on brain and behavioral responses to beverage stimuli.Design: We performed an experiment with 20 healthy-weight individuals who were randomly assigned to consume 1 of 2 sugar-sweetened beverages daily for 21 d, underwent 2 functional MRI sessions, and completed behavioral and explicit hedonic assessments.Results: Consistent with preclinical experiments, daily beverage consumption resulted in decreases in dorsal striatal response during receipt of the consumed beverage (r = -0.46) and decreased ventromedial prefrontal response during logo-elicited anticipation (r = -0.44). This decrease in the prefrontal response correlated with increases in behavioral disinhibition toward the logo of the consumed beverage (r = 0.54; P = 0.02). Daily beverage consumption also increased precuneus response to both juice logos compared with a tasteless control (r = 0.45), suggesting a more generalized effect toward beverage cues. Last, the repeated consumption of 1 beverage resulted in an explicit hedonic devaluation of a similar nonconsumed beverage (P < 0.001).Conclusions: Analogous to previous reports, these initial results provide convergent data for a role of regular sugar-sweetened beverage intake in altering neurobehavioral responses to the regularly consumed beverage that may also extend to other beverage stimuli. Future research is required to provide evidence of replication in a larger sample and to establish whether the neurobehavioral adaptations observed herein are

  17. Hydrocarbons in soils: Origin, composition, and behavior (Review)

    NASA Astrophysics Data System (ADS)

    Gennadiev, A. N.; Pikovskii, Yu. I.; Tsibart, A. S.; Smirnova, M. A.

    2015-10-01

    It has been shown that a large body of evidence on the sources, transformation, and migration of hydrocarbons in soils has been acquired by different researchers. Available data about the origin and behavior of hydrocarbon gases, total petroleum hydrocarbons, polycyclic aromatic hydrocarbons, alkanes, and other compounds have been considered successively. A wide range of natural and anthropogenic factors affecting the transformation and migration of hydrocarbons in soils have been analyzed. The indicative value of these compounds has been explained. At the same time, many problems related to hydrocarbons in soils are still insufficiently understood. Sparse and fragmentary data are available in the literature on the interaction of different hydrocarbon groups in the soil. Few data refer to the features of hydrocarbons in background zonal soils; there are almost no interzonal comparisons. The behavior of hydrocarbons in soils of different landscape-geographical positions is characterized in isolated publications. The hydrocarbon status of soils as an integral complex of interrelated hydrocarbons is almost not analyzed. Hydrocarbons of a single class (polycyclic aromatic hydrocarbons, hydrocarbon gases, n-alkanes, etc.) are usually characterized in each publication.

  18. Tethered Nanoparticle -Polymer Composites: Phase behavior and rheology

    NASA Astrophysics Data System (ADS)

    Mangal, Rahul; Archer, Lynden A.

    2014-03-01

    Polymer nanocomposites with particle radius (a) approaching the radius of gyration (Rg) of entangled host polymer have been reported to exhibit an unusual negative reinforcement effect, which leads to an anomalous reduction in relative an anomalous reduction in relative viscosity at low particle loadings (φ) . This so-called Non-Einsteinian flow behavior is understood to be sensitive to the dispersion state of particles in host polymer. We studied suspensions of SiO2 nanoparticles tethered with polethylene glycol (PEG) in polymethylmethacralate (PMMA) with molecular weights (Mw) from 17 KDa to 280 KDa. Due to strong enthalpic interactions between PEG and PMMA (χ = -0.65), nanoparticles are expected to be well-dispersed, independent of Mw of PMMA. Using small angle x-ray scattering measurements we show that the phase stability of suspensions depends on Mw of the tethered PEG, host PMMA, and φ. Particles functionalized with low molecular weight PEG aggregate at low φ, but disperse at high φ. In contrast, nanoparticles functionalized with higher molecular weight PEG are well dispersed for host chain lengths (P) to tethered chain length (N), (P/N), is as high as 160. The stability boundary of these suspensions extends well beyond expectations for nanocomposites based on tethered PEG chains suspended in PEG. Through in-depth analysis of rheology and x-ray photon correlation spectra we explore the fundamental origins of non-Einsteinian flow behavior. King Abdullah University of Science and Technology (KAUST), Advanced Photon Source (APS).

  19. [Abnormal behavior and adaptation problems in dogs and cats and their pharmacologic control].

    PubMed

    Jöchle, W

    1998-11-01

    Small animal practitioners are increasingly confronted with patients showing adaptation related problems (ARP) which are expressed as disturbed or abnormal behavior (DAB). As a result, practitioners are asked increasingly to euthanize animals which seemingly cannot be socialized. In healthy dogs and cats, three main causes for DAB can be detected: refusal of obedience because of the drive for dominance; anxiety and frustration; and geriatric DAB. Increasingly, disease conditions not readily diagnosed can cause DAB, especially hypothyroidism. Influencing and contributing factors to DAB are breed, sex, experiences as a puppy, behavior of owners, changes in the pet's environment. ARPs may also cause disturbances in the condition of skin and fur, e.g. atopic dermatitis, pruritus sine materia, lick granuloma, and of the intestinal organs (vomiting, irritated bowel syndrome) and may result in an immune deficiency. Therapeutic approaches include behavioral therapy, surgical or hormonal castration with progestins or antiandrogens, substitution with thyroxin in cases with hypothyroidism, and/or the use of psychopharmaca, most prominently of modern antidepressiva like amitriptyline; buspirone; clomipramine and fluoxetine, but also of selegiline, a mono-aminoxydase inhibitor. These compounds, among other effects, are elevating prolactin levels. This seems to allow to formulate a working hypothesis: in the canine species, prolactin is obviously a hormone enabling socialization; hence all drugs which safely cause an increase in prolactin production might be suitable to manage or control ARPs and DAB in the dog, but also in the cat. Higher levels of prolactin than those required for socialization, as seen in nursing bitches or some clinically overt cases of pseudopregnancy, may cause maternal aggression and can be controlled with prolactin inhibitors, if needed.

  20. Microstructure, mechanical property, biodegradation behavior, and biocompatibility of biodegradable Fe-Fe2O3 composites.

    PubMed

    Cheng, J; Huang, T; Zheng, Y F

    2014-07-01

    In this study, the effects of Fe2O3 (addition, 2, 5, 10, and 50 wt %) on the microstructure, mechanical properties, corrosion behaviors, and in vitro biocompatibility of Fe-Fe2O3 composites fabricated by spark plasma sintering were systematically investigated as a novel-structure biodegradable metallic material. The results of X-ray diffraction analysis and optical microscopy indicated that Fe-Fe2O3 composite is composed of α-Fe and FeO instead of Fe2O3. Both eletrochemical measurements and immersion test showed a faster degradation rate of Fe-2Fe2O3 and Fe-5Fe2O3 composites than pure iron and Fe-5Fe2O3 exhibited the fastest corrosion rate among these composites. Besides, the effect of Fe2O3 on the corrosion behavior of Fe-Fe2O3 composites was discussed. The extracts of Fe-Fe2O3 composite exhibited no cytotoxicity to both ECV304 and L929 cells, whereas greatly reduced cell viabilities of vascular smooth muscle cells. In addition, good hemocompatibility of all Fe-Fe2O3 composites and pure iron was obtained. To sum up, Fe-5Fe2O3 composite is a promising alternative for biodegradable stent material with elevated corrosion rate, enhanced mechanical properties, as well as excellent biocompatibility.

  1. Strengthening behavior of chopped multi-walled carbon nanotube reinforced aluminum matrix composites

    SciTech Connect

    Shin, S.E.; Bae, D.H.

    2013-09-15

    Strengthening behavior of the aluminum composites reinforced with chopped multi-walled carbon nanotubes (MWCNTs) or aluminum carbide formed during annealing at 500 °C has been investigated. The composites were fabricated by hot-rolling the powders which were ball-milled under various conditions. During the early annealing process, aluminum atoms can cluster inside the tube due to the diffusional flow of aluminum atoms into the tube, providing an increase of the strength of the composite. Further annealing induces the formation of the aluminum carbide phase, leading to an overall drop in the strength of the composites. While the strength of the composites can be evaluated according to the rule of mixture, a particle spacing effect can be additionally imparted on the strength of the composites reinforced with the chopped MWCNTs or the corresponding carbides since the reinforcing agents are smaller than the submicron matrix grains. - Highlights: • Strengthening behavior of chopped CNT reinforced Al-based composites is investigated. • Chopped CNTs have influenced the strength and microstructures of the composites. • Chopped CNTs are created under Ar- 3% H2 atmosphere during mechanical milling. • Strength can be evaluated by the rule of the mixture and a particle spacing effect.

  2. Computational Simulation of Continuous Fiber-Reinforced Ceramic Matrix Composites Behavior

    NASA Technical Reports Server (NTRS)

    Murthy, Pappu L. N.; Chamis, Christos C.; Mital, Subodh K.

    1996-01-01

    This report describes a methodology which predicts the behavior of ceramic matrix composites and has been incorporated in the computational tool CEMCAN (CEramic Matrix Composite ANalyzer). The approach combines micromechanics with a unique fiber substructuring concept. In this new concept, the conventional unit cell (the smallest representative volume element of the composite) of the micromechanics approach is modified by substructuring it into several slices and developing the micromechanics-based equations at the slice level. The methodology also takes into account nonlinear ceramic matrix composite (CMC) behavior due to temperature and the fracture initiation and progression. Important features of the approach and its effectiveness are described by using selected examples. Comparisons of predictions and limited experimental data are also provided.

  3. Weather, habitat composition, and female behavior interact to modify offspring survival in Greater Sage-Grouse.

    PubMed

    Gibson, Daniel; Blomberg, Erik J; Atamian, Michael T; Sedinger, James S

    2017-01-01

    Weather is a source of environmental variation that can affect population vital rates. However, the influence of weather on individual fitness is spatially heterogeneous and can be driven by other environmental factors, such as habitat composition. Therefore, individuals can experience reduced fitness (e.g., decreased reproductive success) during poor environmental conditions through poor decisions regarding habitat selection. This requires, however, that habitat selection is adaptive and that the organism can correctly interpret the environmental cues to modify habitat use. Greater Sage-Grouse (Centrocercus urophasianus) are an obligate of the sagebrush ecosystems of western North America, relying on sagebrush for food and cover. Greater Sage-Grouse chicks, however, require foods with high nutrient content (i.e., forbs and insects), the abundance of which is both temporally and spatially dynamic and related primarily to water availability. Our goal was to assess whether nest site selection and movements of broods by females reduced the negative effect of drought on offspring survival. As predicted, chick survival was negatively influenced by drought severity. We found that sage-grouse females generally preferred to nest and raise their young in locations where their chicks would experience higher survival. We also found that use of habitats positively associated with chick survival were also positively associated with drought severity, which suggests that females reduced drought impacts on their dependent young by selecting more favorable environments during drought years. Although our findings suggest that female nest site selection and brood movement rates can reduce the negative effects of drought on early offspring survival, the influence of severe drought conditions was not completely mitigated by female behavior, and that drought conditions should be considered a threat to Greater Sage-Grouse population persistence.

  4. Elastic Behavior of Y-1-2-3/SILVER Composites

    NASA Astrophysics Data System (ADS)

    Shekhar, S.; Reddy, R. Ravinder; Reddy, P. Venugopal; Mulay, V. N.

    A series of Y-1-2-3/Ag high Tc superconducting composites have been prepared using the sol-gel method by sintering at three different sintering temperatures, viz. 910°C, 945°C, and 975°C. After the usual characterization by XRD, electrical resistance, bulk density, and porosity measurements, the longitudinal (V1) and shear wave (Vs) velocities were measured by the pulse transmission technique. Using the experimental data, several elasticity parameters such as Young's modulus (E), rigidity modulus (G), etc. were evaluated. The variation of elastic constants with dopant concentration has been explained in terms of the binding forces between various atoms of the superconductor. A linear relationship between the superconducting transition temperature (Tc) and the Debye temperature (θD) has also been obtained.

  5. The viscoelastic behavior of a composite in a thermal environment

    NASA Technical Reports Server (NTRS)

    Morris, D. H.; Brinson, H. F.; Griffith, W. I.; Yeow, Y. T.

    1979-01-01

    A proposed method for the accelerated predictions of modulus and life times for time dependent polymer matrix composite laminates is presented. The method, based on the time temperature superposition principle and lamination theory, is described in detail. Unidirectional reciprocal of compliance master curves and the shift functions needed are presented and discussed. Master curves for arbitrarily oriented unidirectional laminates are predicted and compared with experimantal results obtained from master curves generated from 15 minute tests and with 25 hour tests. Good agreement is shown. Predicted 30 deg and 60 deg unidirectional strength master curves are presented and compared to results of creep rupture tests. Reasonable agreement is demonstrated. In addition, creep rupture results for a (90 deg + or - 60 deg/90 deg) sub 2s laminate are presented.

  6. The use of the spectral method within the fast adaptive composite grid method

    SciTech Connect

    McKay, S.M.

    1994-12-31

    The use of efficient algorithms for the solution of partial differential equations has been sought for many years. The fast adaptive composite grid (FAC) method combines an efficient algorithm with high accuracy to obtain low cost solutions to partial differential equations. The FAC method achieves fast solution by combining solutions on different grids with varying discretizations and using multigrid like techniques to find fast solution. Recently, the continuous FAC (CFAC) method has been developed which utilizes an analytic solution within a subdomain to iterate to a solution of the problem. This has been shown to achieve excellent results when the analytic solution can be found. The CFAC method will be extended to allow solvers which construct a function for the solution, e.g., spectral and finite element methods. In this discussion, the spectral methods will be used to provide a fast, accurate solution to the partial differential equation. As spectral methods are more accurate than finite difference methods, the ensuing accuracy from this hybrid method outside of the subdomain will be investigated.

  7. Marginal adaptation of dentin bonded ceramic inlays: effects of bonding systems and luting resin composites.

    PubMed

    Haller, Bernd; Hässner, Katrin; Moll, Karlheinz

    2003-01-01

    This in vitro study evaluated the marginal adaptation of bonded inlays of lucite-reinforced glass ceramic (Empress) to dentin as influenced by different bonding systems and by luting resin composites (LRCs) with different curing modes. Forty-eight Empress inlays etched with 5% hydrofluoric acid and treated with a silane-coupling agent (Monobond-S) were bonded to two-surface Class II cavities. Two total-etch bonding systems (OptiBond FL, Nexus) and one bonding system with selective enamel etching and a self-conditioning dentin primer (ART Bond) were included in the study. ART Bond was tested with and without the pre-curing of a first layer of adhesive resin selectively applied to the cervical cavity floor (selective double-bond technique). Each bonding system was used in combination with a light-cured resin composite (Prodigy) and a dual-cured LRC (Nexus or Vita Cerec Duo Cement). Marginal integrity was evaluated before and after thermocycling (TC) in a scanning electron microscope (SEM). Dye penetration tests were performed after TC was completed. The median percentages of continuous margin in dentin ranged from 80% to 100% before TC and from 53.5% to 96.1 % after TC. After TC, the influence of the bonding system was more pronounced than that of the LRC. In combination with the LC resin composite, ART Bond with precuring was significantly higher and the Nexus bonding system had significantly lower proportions of continuous margin than all the other bonding systems investigated. Swelling of the adhesive along the gingival margins was frequently found with the Nexus bonding system and with ART Bond without pre-curing. Microleakage was detected with all bonding system/LRC combinations, with somewhat lower rates in specimens completed using the selective double-bond technique. With the exception of the Nexus bonding system, post-TC marginal integrity was not influenced by the curing mode of the LRC (LC vs DC). In conclusion, the marginal quality of dentin bonded

  8. Mechanical behavior and fracture characteristics of off-axis fiber composites. 2: Theory and comparisons

    NASA Technical Reports Server (NTRS)

    Chamis, C. C.; Sinclair, J. H.

    1978-01-01

    The mechanical behavior and stresses inducing fracture modes of unidirectional high-modulus graphite-fiber/epoxy composites subjected to off-axis tensile loads were investigated theoretically. The investigation included the use of composite mechanics, combined-stress failure criteria, and finite-element stress analysis. The results are compared with experimental data and led to the formulation of criteria and convenient plotting procedures for identifying, characterizing, and quantifying these fracture modes.

  9. Creep Behavior of an Oxide/Oxide Composite with Monazite Coating at Elevated Temperatures

    DTIC Science & Technology

    2005-03-01

    research composite of that nature was the General Electric Gen-IV. Results from Zawada et al (37) show fairly poor creep resistance of the N610 fiber...A: Applied Science and Manufacturing: 1005-1013 (1995). 36. Zawada , Larry P., Randall S. Hay, Shin S. Lee, and James Staehler. “Characterization...and High-Temperature Mechanical Behavior of an Oxide/Oxide Composite,” Journal of the American Ceramic Society, 86 [6]: 981-90 (2003). 37. Zawada

  10. Mechanical Properties and Fatigue Behavior of Unitized Composite Airframe Structures at Elevated Temperature

    DTIC Science & Technology

    2014-03-27

    matrix (typically a polymer , metal, or ceramic resin) and the reinforcement (can also be polymeric , metallic, or ceramic) in the form of fibers, whiskers...when all absorbed water was evaporated. Weight loss stabilized in less than 9 days as shown in Figure 12. The specimens were then removed 27 from the...The tension-tension fatigue behavior of newly developed polymer matrix composites (PMCs) and that of a unitized composite was studied. The PMCs

  11. Dry Sliding Wear Behavior of Fly Ash Cenosphere/AZ91D Mg Alloy Composites

    NASA Astrophysics Data System (ADS)

    Yu, S. R.; Huang, Z. Q.

    2014-10-01

    Fly ash cenosphere/AZ91D Mg alloy (FAC/AZ91D) composites were prepared using stir casting method. The effects of the applied load, the wearing time, and the diameter and the content of fly ash cenosphere on the wear behavior of the composites were investigated under dry sliding condition. The results showed the wear resistance of FAC/AZ91D composites is generally better than that of AZ91D Mg alloy. The mass fraction and diameter of FAC have important effects on the wear resistance of the composites, and the wear resistance of the composites is excellent when the mass fraction and diameter of FAC are moderate. When the mass fraction and diameter of FAC are more than the critical values, the wear resistance of the composites lowers again. The wear resistance of the composites decreases with the increase in the applied load. The relationship between the worn mass loss and the applied load is nonlinear. When the applied load is smaller, the worn mass loss of the composites increases rapidly with the increase of the applied load. These research results show that the composites have broad application prospects under dry sliding wear condition, and they can provide guidance for the selection of the raw materials, the structure design, and the application conditions of the composites.

  12. Deformation behavior of metallic glass composites reinforced with shape memory nanowires studied via molecular dynamics simulations

    NASA Astrophysics Data System (ADS)

    Şopu, D.; Stoica, M.; Eckert, J.

    2015-05-01

    Molecular dynamics simulations indicate that the deformation behavior and mechanism of Cu64Zr36 composite structures reinforced with B2 CuZr nanowires are strongly influenced by the martensitic phase transformation and distribution of these crystalline precipitates. When nanowires are distributed in the glassy matrix along the deformation direction, a two-steps stress-induced martensitic phase transformation is observed. Since the martensitic transformation is driven by the elastic energy release, the strain localization behavior in the glassy matrix is strongly affected. Therefore, the composite materials reinforced with a crystalline phase, which shows stress-induced martensitic transformation, represent a route for controlling the properties of glassy materials.

  13. An overview of the crash dynamics failure behavior of metal and composite aircraft structures

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.; Boitnott, Richard L.; Fasanella, Edwin L.; Jones, Lisa E.

    1991-01-01

    An overview of failure behavior results is presented from some of the crash dynamics research conducted with concepts of aircraft elements and substructure not necessarily designed or optimized for energy absorption or crash loading considerations. Experimental and analytical data are presented that indicate some general trends in the failure behavior of a class of composite structures that includes fuselage panels, individual fuselage sections, fuselage frames, skeleton subfloors with stringers and floor beams without skin covering, and subfloors with skin added to the frame stringer structure. Although the behavior is complex, a strong similarity in the static/dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models.

  14. Failure behavior of generic metallic and composite aircraft structural components under crash loads

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.; Robinson, Martha P.

    1990-01-01

    Failure behavior results are presented from crash dynamics research using concepts of aircraft elements and substructure not necessarily designed or optimized for energy absorption or crash loading considerations. To achieve desired new designs incorporating improved energy absorption capabilities often requires an understanding of how more conventional designs behave under crash loadings. Experimental and analytical data are presented which indicate some general trends in the failure behavior of a class of composite structures including individual fuselage frames, skeleton subfloors with stringers and floor beams without skin covering, and subfloors with skin added to the frame-stringer arrangement. Although the behavior is complex, a strong similarity in the static/dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models.

  15. Group compositional changes impact the social and feeding behaviors of captive hamadryas baboons (Papio hamadryas hamadryas).

    PubMed

    Ryan, Amy M; Hauber, Mark E

    2016-01-01

    The formation and modification of social groups in captivity are delicate management tasks. The ability for personnel to anticipate changes in group dynamics following compositional changes can increase the likelihood of successful management with minimized injury or social instability. Hamadryas baboons (Papio hamadryas hamadryas) have a distinctive multi-level social system comprising of one-male units (OMUs) that can make it difficult to apply knowledge from other primates' multi-female/multi-male social structure to changes imposed onto captive hamadryas baboon groups. We conducted an observational study of the behavioral impacts following the introduction of two females into the group of hamadryas baboons at the Wildlife Conservation Society's Prospect Park Zoo in NY to test hypotheses about the relationships between changes in group composition and social and feeding behavior. Generalized linear mixed models demonstrated that social interactions significantly increased following the compositional changes, even in groups that only experienced member removals. The increase in affiliative social behavior observed suggests that during times of social stress or uncertainty, hamadryas baboons may employ social behavior as a tension-reducing mechanism to negotiate relationships as opposed to using aggression to engage in competitions for ranks and resources. The observed response to compositional changes implies that hamadryas baboons may respond with less aggression than do other Old World monkey species and that levels of affiliative behavior may be a more accurate metric for evaluating introduction success in hamadryas baboons.

  16. Modeling of stress/strain behavior of fiber-reinforced ceramic matrix composites including stress redistribution

    NASA Technical Reports Server (NTRS)

    Mital, Subodh K.; Murthy, Pappu L. N.; Chamis, Christos C.

    1994-01-01

    A computational simulation procedure is presented for nonlinear analyses which incorporates microstress redistribution due to progressive fracture in ceramic matrix composites. This procedure facilitates an accurate simulation of the stress-strain behavior of ceramic matrix composites up to failure. The nonlinearity in the material behavior is accounted for at the constituent (fiber/matrix/interphase) level. This computational procedure is a part of recent upgrades to CEMCAN (Ceramic Matrix Composite Analyzer) computer code. The fiber substructuring technique in CEMCAN is used to monitor the damage initiation and progression as the load increases. The room-temperature tensile stress-strain curves for SiC fiber reinforced reaction-bonded silicon nitride (RBSN) matrix unidirectional and angle-ply laminates are simulated and compared with experimentally observed stress-strain behavior. Comparison between the predicted stress/strain behavior and experimental stress/strain curves is good. Collectively the results demonstrate that CEMCAN computer code provides the user with an effective computational tool to simulate the behavior of ceramic matrix composites.

  17. Bambara-wheat composite flour: rheological behavior of dough and functionality in bread.

    PubMed

    Erukainure, Ochuko L; Okafor, Jane N C; Ogunji, Akinyele; Ukazu, Happiness; Okafor, Ebele N; Eboagwu, Ijeoma L

    2016-11-01

    The rheological behavior and functional properties of doughs from bambara-wheat composite flour was investigated. Bambara-wheat composite flour was prepared by substituting wheat with 0%, 10%, 15%, and 20% of bambara flour. The rheological behavior of their dough was analyzed with Mixolab. Breads produced from the flour were analyzed for physical characteristics. Organoleptic analysis was carried out by 20 panelists. Mixolab analysis revealed, except for stability time, depreciating values for dough consistency (C1), protein weakening (C2), starch gelatinization (C3), amylase activity (C4), and retrogradation (C5) as the inclusion of bambara flour increased. Physical characteristics of the loaves revealed significant (P < 0.05) decreasing bread volume and increasing specific volume, respectively, as bambara inclusion increased. There was significant (P < 0.05) difference between wheat bread and the bambara-wheat composites in all the studied quality attributes. 15% bambara-wheat composite bread was the most accepted amongst the composite breads. Inclusion of bambara flour improved the protein behavior of the composite, but did not evidently show benefits in the baking characteristics.

  18. Two Children with Multiple Disabilities Increase Adaptive Object Manipulation and Reduce Inappropriate Behavior via a Technology-Assisted Program

    ERIC Educational Resources Information Center

    Lancioni, Giulio E.; O'Reilly, Mark F.; Singh, Nirbhay N.; Sigafoos, Jeff; Didden, Robert; Oliva, Doretta; Campodonico, Francesca

    2010-01-01

    Persons with severe to profound multiple disabilities, such as intellectual, visual, and motor disabilities, may be characterized by low levels of adaptive engagement with the environment. They may also display forms of inappropriate, stereotypical behavior (like hand mouthing, that is, putting their fingers into or over their mouths) or…

  19. The Contribution of Children's Self-Regulation and Classroom Quality to Children's Adaptive Behaviors in the Kindergarten Classroom

    ERIC Educational Resources Information Center

    Rimm-Kaufman, Sara E.; Curby, Tim W.; Grimm, Kevin J.; Brock, Laura L.; Nathanson, Lori

    2009-01-01

    In this study, the authors examined the extent to which children's self-regulation upon kindergarten entrance and classroom quality in kindergarten contributed to children's adaptive classroom behavior. Children's self-regulation was assessed using a direct assessment upon entrance into kindergarten. Classroom quality was measured on the basis of…

  20. Two Boys with Multiple Disabilities Increasing Adaptive Responding and Curbing Dystonic/Spastic Behavior via a Microswitch-Based Program

    ERIC Educational Resources Information Center

    Lancioni, Giulio E.; Singh, Nirbhay N.; O'Reilly, Mark F.; Sigafoos, Jeff; Didden, Robert; Oliva, Doretta

    2009-01-01

    A recent study has shown that microswitch clusters (i.e., combinations of microswitches) and contingent stimulation could be used to increase adaptive responding and reduce dystonic/spastic behavior in two children with multiple disabilities [Lancioni, G. E., Singh, N. N., Oliva, D., Scalini, L., & Groeneweg, J. (2003). Microswitch clusters to…

  1. Emotional Intelligence and Adaptive Success of Nurses Caring for People with Mental Retardation and Severe Behavior Problems

    ERIC Educational Resources Information Center

    Gerits, Linda; Derksen, Jan J. L.; Verbruggen, Antoine B.

    2004-01-01

    The emotional intelligence profiles, gender differences, and adaptive success of 380 Dutch nurses caring for people with mental retardation and accompanying severe behavior problems are reported. Data were collected with the Bar-On Emotional Quotient Inventory, Utrecht-Coping List, Utrecht-Burnout Scale, MMPI-2, and GAMA. Absence due to illness…

  2. An Overview of Intervention Options for Promoting Adaptive Behavior of Persons with Acquired Brain Injury and Minimally Conscious State

    ERIC Educational Resources Information Center

    Lancioni, Giulio E.; Bosco, Andrea; Belardinelli, Marta Olivetti; Singh, Nirbhay N.; O'Reilly, Mark F.; Sigafoos, Jeff

    2010-01-01

    This paper presents an overview of the studies directed at helping post-coma persons with minimally conscious state improve their adaptive behavior. Twenty-one studies were identified for the 2000-2010 period (i.e., a period in which an intense debate has occurred about diagnostic, rehabilitative, prognostic, and ethical issues concerning people…

  3. Adapting Phonological Awareness Interventions for Children with Down Syndrome Based on the Behavioral Phenotype: A Promising Approach?

    ERIC Educational Resources Information Center

    Lemons, Christopher J.; King, Seth A.; Davidson, Kimberly A.; Puranik, Cynthia S.; Fulmer, Deborah; Mrachko, Alicia A.; Partanen, Jane; Al Otaiba, Stephanie; Fidler, Deborah J.

    2015-01-01

    Many children with Down syndrome demonstrate deficits in phonological awareness, a prerequisite to learning to read in an alphabetic language. The purpose of this study was to determine whether adapting a commercially available phonological awareness program to better align with characteristics associated with the behavioral phenotype of Down…

  4. The Relationship between Parent Report of Adaptive Behavior and Direct Assessment of Reading Ability in Children with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Arciuli. Joanne; Stevens, Kirsten; Trembath, David; Simpson, Ian Craig

    2013-01-01

    Purpose: This study was designed to shed light on the profile of reading ability in children with autism spectrum disorder (ASD). A key aim was to examine the relationship between parent report of adaptive behavior and direct assessment of reading ability in these children. Method: The authors investigated children's reading ability using the Wide…

  5. The roles of life-history selection and sexual selection in the adaptive evolution of mating behavior in a beetle.

    PubMed

    Maklakov, Alexei A; Cayetano, Luis; Brooks, Robert C; Bonduriansky, Russell

    2010-05-01

    Although there is continuing debate about whether sexual selection promotes or impedes adaptation to novel environments, the role of mating behavior in such adaptation remains largely unexplored. We investigated the evolution of mating behavior (latency to mating, mating probability and duration) in replicate populations of seed beetles Callosobruchus maculatus subjected to selection on life-history ("Young" vs. "Old" reproduction) under contrasting regimes of sexual selection ("Monogamy" vs. "Polygamy"). Life-history selection is predicted to favor delayed mating in "Old" females, but sexual conflict under polygamy can potentially retard adaptive life-history evolution. We found that life-history selection yielded the predicted changes in mating behavior, but sexual selection regime had no net effect. In within-line crosses, populations selected for late reproduction showed equally reduced early-life mating probability regardless of mating system. In between-line crosses, however, the effect of life-history selection on early-life mating probability was stronger in polygamous lines than in monogamous ones. Thus, although mating system influenced male-female coevolution, removal of sexual selection did not affect the adaptive evolution of mating behavior. Importantly, our study shows that the interaction between sexual selection and life-history selection can result in either increased or decreased reproductive divergence depending on the ecological context.

  6. Family Emotional Climate and Sibling Relationship Quality: Influences on Behavioral Problems and Adaptation in Preschool-Aged Children

    ERIC Educational Resources Information Center

    Modry-Mandell, Kerri L.; Gamble, Wendy C.; Taylor, Angela R.

    2007-01-01

    We examined the impact of family emotional climate and sibling relationship quality on behavioral problems and adaptation in preschool-aged children. Participants were 63 mothers with a preschool-aged child enrolled in a Southern Arizona Head Start Program. Siblings were identified as children closest in age to target child. Mothers of…

  7. Promoting Adaptive Behavior in Persons with Acquired Brain Injury, Extensive Motor and Communication Disabilities, and Consciousness Disorders

    ERIC Educational Resources Information Center

    Lancioni, Giulio E.; Singh, Nirbhay N.; O'Reilly, Mark F.; Sigafoos, Jeff; Belardinelli, Marta Olivetti; Buonocunto, Francesca; Sacco, Valentina; Navarro, Jorge; Lanzilotti, Crocifissa; De Tommaso, Marina; Megna, Marisa; Badagliacca, Francesco

    2012-01-01

    These two studies extended the evidence on the use of technology-based intervention packages to promote adaptive behavior in persons with acquired brain injury and multiple disabilities. Study I involved five participants in a minimally conscious state who were provided with intervention packages based on specific arrangements of optic, tilt, or…

  8. Adaptation of Social Problem Solving for Children Questionnaire in 6 Age Groups and its Relationships with Preschool Behavior Problems

    ERIC Educational Resources Information Center

    Dereli-Iman, Esra

    2013-01-01

    Social Problem Solving for Child Scale is frequently used to determine behavioral problems of children with their own word and to identify ways of conflict encountered in daily life, and interpersonal relationships in abroad. The primary purpose of this study was to adapt the Wally Child Social Problem-Solving Detective Game Test. In order to…

  9. Compressive behavior of undulations in filament-wound composites

    NASA Technical Reports Server (NTRS)

    Jensen, David W.; Pickenheim, Timothy R.

    1993-01-01

    The compressive performance of a filament-wound cylinder can be severely degraded by unavoidable fiber curvatures due to the presence of crossover bands. These crossover bands contain fiber undulations which influence the compressive strength, stiffness, and associated failure mechanisms of a filament-wound structure. The primary objectives of this study were to identify failure mechanisms and measure the compressive strength and stiffness of test specimens which model the microundulations. Compressive tests were conducted on flat-panel coupons which were developed to model the mechanics of large-scale fiber undulation regions in filament-wound composite cylinders. The primary effect of the undulation regions within a filament-wound structure is to initiate failure. Depending on the overall laminate configuration, the failure process includes various combinations of failure mechanisms, such as delaminations, matrix splitting and/or fiber fracture. These failure mechanisms are aggravated by the presence of large deformations caused by the reduction in local compressive stiffness and the introduction of complex material couplings due to the fiber undulation. Furthermore, the adjacent layers have been shown to strongly influence the compressive strength, stiffness, and associated failure mechanisms by weakening or reinforcing the laminate.

  10. Oxidation Behavior of Carbon Fiber-Reinforced Composites

    NASA Technical Reports Server (NTRS)

    Sullivan, Roy M.

    2008-01-01

    OXIMAP is a numerical (FEA-based) solution tool capable of calculating the carbon fiber and fiber coating oxidation patterns within any arbitrarily shaped carbon silicon carbide composite structure as a function of time, temperature, and the environmental oxygen partial pressure. The mathematical formulation is derived from the mechanics of the flow of ideal gases through a chemically reacting, porous solid. The result of the formulation is a set of two coupled, non-linear differential equations written in terms of the oxidant and oxide partial pressures. The differential equations are solved simultaneously to obtain the partial vapor pressures of the oxidant and oxides as a function of the spatial location and time. The local rate of carbon oxidation is determined at each time step using the map of the local oxidant partial vapor pressure along with the Arrhenius rate equation. The non-linear differential equations are cast into matrix equations by applying the Bubnov-Galerkin weighted residual finite element method, allowing for the solution of the differential equations numerically.

  11. Adaptive evolution of a derived radius morphology in manakins (Aves, Pipridae) to support acrobatic display behavior.

    PubMed

    Friscia, Anthony; Sanin, Gloria D; Lindsay, Willow R; Day, Lainy B; Schlinger, Barney A; Tan, Josh; Fuxjager, Matthew J

    2016-06-01

    The morphology of the avian skeleton is often studied in the context of adaptations for powered flight. The effects of other evolutionary forces, such as sexual selection, on avian skeletal design are unclear, even though birds produce diverse behaviors that undoubtedly require a variety of osteological modifications. Here, we investigate this issue in a family of passerine birds called manakins (Pipridae), which have evolved physically unusual and elaborate courtship displays. We report that, in species within the genus Manacus, the shaft of the radius is heavily flattened and shows substantial solidification. Past work anecdotally notes this morphology and attributes it to the species' ability to hit their wings together above their heads to produce loud mechanical sonations. Our results show that this feature is unique to Manacus compared to the other species in our study, including a variety of taxa that produce other sonations through alternate wing mechanisms. At the same time, our data reveal striking similarities across species in total radius volume and solidification. Together, this suggests that supposedly adaptive alterations in radial morphology occur within a conserved framework of a set radius volume and solidness, which in turn is likely determined by natural selection. Further allometric analyses imply that the radius is less constrained by body size and the structural demands that underlie powered flight, compared to other forelimb bones that are mostly unmodified across taxa. These results are consistent with the idea that the radius is more susceptible to selective modification by sexual selection. Overall, this study provides some of the first insight into the osteological evolution of passerine birds, as well as the way in which opposing selective forces can shape skeletal design in these species. J. Morphol. 277:766-775, 2016. © 2016 Wiley Periodicals, Inc.

  12. High-Cycle Fatigue Behavior of a Nicalon(tm)/Si-N-C Composite

    NASA Technical Reports Server (NTRS)

    Verrilli, Michael J.; Kalluri, Sreeramesh; Kantzos, Peter T.

    1999-01-01

    Elevated temperature, high-cycle fatigue behavior of a woven SiC/Si-N-C ceramic matrix composite system was investigated at 910 C. High frequency (100 Hz) fatigue tests were conducted in air on specimens machined from the composite system, A power-law type fatigue life relationship adequately characterized the high-cycle fatigue data generated in the study. Post failure fractographic and metallographic studies were performed to document the fatigue crack initiation regions and damage mechanisms in the composite system. Fatigue cracks initiated primarily from the corners of the specimens and propagated along the 90 degree fiber tows.

  13. Behavior of magnetic field and eddy current in a magnetostriction based bi-layered composite

    NASA Astrophysics Data System (ADS)

    Zhang, Kewei; Zhang, Kehao; Liu, Huifeng; Li, Junlin

    2016-12-01

    In this paper, we presented a theoretical method for studying the behavior of magnetic field intensity and eddy current inside a magnetostriction based bi-layered composite. Firstly, the mathematical model for the electromagnetic field in the composite was established. Then, the governing equation for determining the magnetic field intensity and eddy current was solved. Furthermore, the effect of the composite's conductivity on the magnetic field intensity and eddy current were discussed. Lastly, by comparing with the well known R.L. Stoll's equation, the magnetic field intensity calculated based on our equation showed a less than 0.5% error.

  14. Overview Of Structural Behavior and Occupant Responses from Crash Test of a Composite Airplane

    NASA Technical Reports Server (NTRS)

    Jones, Lisa E.; Carden, Huey D.

    1995-01-01

    As part of NASA's composite structures crash dynamics research, a general aviation aircraft with composite wing, fuselage and empennage (but with metal subfloor structure) was crash tested at the NASA Langley Research Center Impact Research Facility. The test was conducted to determine composite aircraft structural behavior for crash loading conditions and to provide a baseline for a similar aircraft test with a modified subfloor. Structural integrity and cabin volume were maintained. Lumbar loads for dummy occupants in energy absorbing seats wer substantially lower than those in standard aircraft seats; however, loads in the standard seats were much higher that those recorded under similar conditions for an all-metallic aircraft.

  15. Influence of Reinforcement Size on Microplastic Deformation Behavior of SiCP/Al Composites

    NASA Astrophysics Data System (ADS)

    Yan, Yiwu; Geng, Lin; Liu, Dayong

    The microplastic deformation behavior of 20 vol.% SiCp/Al composites with various SiC particle sizes were investigated. The SiC particles are in four nominal sizes of 1, 5, 20 and 56 µm. The experimental results showed that the micro-yield strength is very sensitive to composite microstructure features. As the particle size increases, the micro-yield strength of composites decrease firstly, and then increase. The observed results were attributed to thermal residual stress and dislocation density due to the large difference in coefficient of thermal expansion between the matrix and reinforcement.

  16. Influence of Stacking Sequence and Notch Angle on the Charpy Impact Behavior of Hybrid Composites

    NASA Astrophysics Data System (ADS)

    Behnia, S.; Daghigh, V.; Nikbin, K.; Fereidoon, A.; Ghorbani, J.

    2016-09-01

    The low-velocity impact behavior of hybrid composite laminates was investigated. The epoxy matrix was reinforced with aramid, glass, basalt, and carbon fabrics using the hand lay-up technique. Different stacking sequences and notch angles were and notch angles considered and tested using a Charpy impact testing machine to study the hybridization and notch angle effects on the impact response of the hybrid composites. The energy absorption capability of specimens with different stacking sequences and notch angles is compared and discussed. It is shown that the hybridization can enhance the mechanical performance of composite materials.

  17. Polarization Raman Microscopic Study of Molecular Alignment Behavior in Liquid Crystal/Polymer Composite Films

    NASA Astrophysics Data System (ADS)

    Murashige, Takeshi; Fujikake, Hideo; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2005-12-01

    We clarified that the molecular alignment of aggregated polymers is partially synchronized with liquid crystal (LC) director reorientation in an LC/polymer composite film. The molecular alignment behavior in composite films with LC- and polymer-rich regions formed by photopolymerization-induced phase separation was investigated using polarization Raman spectral microscopy. Raman scattering intensity induced by aligned side chains of polymers in the LC-rich region changed with LC director reorientation when voltage was applied to the composite film. It was confirmed for the first time that polymers capable of movement are formed in the LC-rich region.

  18. Tensile Behavior of Tungsten/Niobium Composites at 1300 to 1600 K

    NASA Technical Reports Server (NTRS)

    Yun, Hee Mann; Titran, Robert H.

    1989-01-01

    The tensile behavior of continuous tungsten fiber reinforced niobium composites (W/Nb), fabricated by an arc-spray process, was studied in the 1300 to 1600 K temperature range. The tensile properties of the fiber and matrix components as well as of the composites were measured and were compared to rule of mixtures (ROM) predictions. The deviation from the ROM was found to depend upon the chemistry of the tungsten alloy fibers, with positive deviations for ST300/Nb (i.e., stronger composite strength than the ROM) and negative or zero deviations for 218/Nb.

  19. Creep behavior of tungsten/niobium and tungsten/niobium-1 percent zirconium composites

    NASA Technical Reports Server (NTRS)

    Petrasek, D. W.; Titran, R. H.

    1988-01-01

    A study was conducted to determine the feasibility of using tungsten fiber reinforced niobium or niobium-1 percent zirconium matrix composites to meet the anticipated increased temperature and creep resistance requirements imposed by advanced space power systems. The results obtained on the short time tensile properties indicated that W/Nb composites showed significant improvements in high temperature strength and offer significant mass reductions for high temperature space power systems. The prime material requirement for space power systems applications is long time creep resistance. A study was conducted to determine the effect of high temperature exposure on the properties of these composites, with emphasis upon their creep behavior at elevated temperatures.

  20. Effect of Ductile Agents on the Dynamic Behavior of SiC3D Network Composites

    NASA Astrophysics Data System (ADS)

    Zhu, Jingbo; Wang, Yangwei; Wang, Fuchi; Fan, Qunbo

    2016-10-01

    Co-continuous SiC ceramic composites using pure aluminum, epoxy, and polyurethane (PU) as ductile agents were developed. The dynamic mechanical behavior and failure mechanisms were investigated experimentally using the split Hopkinson pressure bar (SHPB) method and computationally by finite element (FE) simulations. The results show that the SiC3D/Al composite has the best overall performance in comparison with SiC3D/epoxy and SiC3D/PU composites. FE simulations are generally consistent with experimental data. These simulations provide valuable help in predicting mechanical strength and in interpreting the experimental results and failure mechanisms. They may be combined with micrographs for fracture characterizations of the composites. We found that interactions between the SiC phase and ductile agents under dynamic compression in the SHPB method are complex, and that interfacial condition is an important parameter that determines the mechanical response of SiC3D composites with a characteristic interlocking structure during dynamic compression. However, the effect of the mechanical properties of ductile agents on dynamic behavior of the composites is a second consideration in the production of the composites.

  1. Solid Particle Erosion Behaviors of Carbon-Fiber Epoxy Composite and Pure Titanium

    NASA Astrophysics Data System (ADS)

    Cai, Feng; Gao, Feng; Pant, Shashank; Huang, Xiao; Yang, Qi

    2016-01-01

    Rotor blades of Bell CH-146 Griffon helicopter experience excessive solid particle erosion at low altitudes in desert environment. The rotor blade is made of an advanced light-weight composite which, however, has a low resistance to solid particle erosion. Coatings have been developed and applied to protect the composite blade. However, due to the influence of coating process on composite material, the compatibility between coating and composite base, and the challenges of repairing damaged coatings as well as the inconsistency between the old and new coatings, replaceable thin metal shielding is an alternative approach; and titanium, due to its high-specific strength and better formability, is an ideal candidate. This work investigates solid particle erosion behaviors of carbon-fiber epoxy composite and titanium in order to assess the feasibility of titanium as a viable candidate for erosion shielding. Experiment results showed that carbon-fiber epoxy composite showed a brittle erosion behavior, whereas titanium showed a ductile erosion mode. The erosion rate on composite was 1.5 times of that on titanium at impingement angle 15° and increased to 5 times at impact angle 90°.

  2. Isotactic polypropylene carbon nanotube composites -- crystallization and ordering behavior

    NASA Astrophysics Data System (ADS)

    Georgiev, Georgi; Judith, Robert; Gombos, Erin; McIntyre, Michael; Schoen, Scott; Cebe, Peggy; Mattera, Michael

    2010-03-01

    The field of Polymer Nanocomposites (PNCs) is growing steadily in recent years. We use carbon nanotubes (CNTs) to affect the crystallization behavior of the polymers. Isotactic Polypropylene (iPP) is very widely used and is a good model system to understand the physics of other similar polymers. iPP/CNT PNCs form α, β, and γ crystallographic phases under a variety of crystallization conditions: non-isothermal and isothermal melt crystallization, shear, stress, fiber extrusion, etc. The crystal growth is altered from spherulitic to α-fibrillar upon the nucleation effect of CNTs. We are studying the effect of different temperature treatment schemes and different isothermal crystallization conditions. We found also that the smectic ordering in iPP is improved by the introduction of CNTs. We use Differential Scanning Calorimetry, Wide Angle X-ray scattering, Microscopic Transmission Ellipsometry and Avrami analysis. Research supported by: Assumption College Faculty Development Grant, funding for students' stipends, instrumentation and supplies, the NSF Polymers Program of the DMR, grant (DMR-0602473) and NASA grant (NAG8-1167).

  3. Fracture behavior of unidirectional boron/aluminum composite laminates

    NASA Technical Reports Server (NTRS)

    Goree, J. G.; Jones, W. F.

    1983-01-01

    An experiment was conducted to verify the results of mathematical models which predict the stresses and displacements of fibers and the amount of damage growth in a center-notched lamina as a function of the applied remote stress and the matrix and fiber material properties. A brittle lacquer coating was used to detect the yielding in the matrix while X-ray techniques were used to determine the number of broken fibers in the laminate. The notched strengths and the amounts of damage found in the specimens agree well with those predicted by the mathematical model. It is shown that the amount of damage and the crack opening displacement does not depend strongly on the number of plies in the laminate for a given notch width. By heat-treating certain laminates to increase the yield stress of the alumina matrix, the effect of different matrix properties on the fracture behavior was investigated. The stronger matrix is shown to weaken the notched laminate by decreasing the amount of matrix damage, thereby making the laminate more notch sensitive.

  4. Tribological behavior study on Ti-Nb-Sn/hydroxyapatite composites in simulated body fluid solution.

    PubMed

    Chen, Yuyong; Wang, Xiaopeng; Xu, Lijuan; Liu, Zhiguang; Kee, Do Woo

    2012-06-01

    In this study, Ti-35Nb-2.5Sn/xhydroxyapatite (HA) composites were sintered by pulse current activated sintering (PCAS) from powders milled for different time. These sintered composites were expected to be potential biomaterials. Ca(3)(PO(4))(2) phase which could increase hardness of sintered composites was found in the Ti-35Nb-2.5Sn/15HA composite sintered from 12 h milled powders. The sintered composites had low elastic modulus (18∼26 GPa) and high compression strength. Due to the importance of friction and wear in biomaterials application, the tribological behavior of sintered composites was studied in simulated body fluid (SBF) solution. Results revealed that milling time and HA content of powders could affect wear properties of sintered composites. The major wear mechanism was abrasive wear in the wear test. The wear rate and friction coefficient decreased when milling time and HA content of powders increased. The lowest friction coefficient (0.1223) was obtained in the Ti-35Nb-2.5Sn/15HA composite sintered from 12 h milled powders, and this composite had superior wear resistance.

  5. Rate dependent stress-strain behavior of advanced polymer matrix composites

    NASA Technical Reports Server (NTRS)

    Gates, Thomas S.

    1991-01-01

    The formulation of an elastic/viscoplastic constitutive model which was used to predict the measured behavior of graphite/thermoplastic and graphite/bismaleimide composite materials at elevated temperature is described. The model incorporates the concepts of overstress and effective strain/strain to provide a simple formulation which was able to account for material behavior under monotonic tension or compression loads over a temperature range of 23 to 200 C. Observed behavior such as stress relaxation and steady state creep, in off-axis tension and compression tests, were predicted by the model. Material constants required by the model were extracted from simple off-axis test data.

  6. Stress or no stress: mineralocorticoid receptors in the forebrain regulate behavioral adaptation.

    PubMed

    ter Horst, J P; van der Mark, M H; Arp, M; Berger, S; de Kloet, E R; Oitzl, M S

    2012-07-01

    Corticosteroid effects on cognitive abilities during behavioral adaptation to stress are mediated by two types of receptors. While the glucocorticoid receptor (GR) is mainly involved in the consolidation of memory, the mineralocorticoid receptor (MR) mediates appraisal and initial responses to novelty. Recent findings in humans and mice suggest that under stress, the MR might be involved in the use of different learning strategies. Here, we used male mice lacking the MR in the forebrain (MR(CaMKCre)), which were subjected to 5-10 min acute restraint stress, followed 30 min later by training trials on the circular hole board. Mice had to locate an exit hole using extra- and intra-maze cues. We assessed performance and the use of spatial and stimulus-response strategies. Non-stressed MR(CaMKCre) mice showed delayed learning as compared to control littermates. Prior stress impaired performance in controls, but did not further deteriorate learning in MR(CaMKCre) mice. When stressed, 20-30% of both MR(CaMKCre) and control mice switched from a spatial to a stimulus-response strategy, which rescued performance in MR(CaMKCre) mice. Furthermore, MR(CaMKCre) mice showed increased GR mRNA expression in all CA areas of the hippocampus and an altered basal and stress-induced corticosterone secretion, which supports their role in the modulation of neuroendocrine activity. In conclusion, our data provide evidence for the critical role of MR in the fast formation of spatial memory. In the absence of forebrain MR spatial learning performance was under basal circumstances impaired, while after stress further deterioration of performance was rescued by switching behavior increasingly to a stimulus-response strategy.

  7. Some psychophysiological and behavioral aspects of adaptation to simulated autonomous Mission to Mars

    NASA Astrophysics Data System (ADS)

    Gushin, V.; Shved, D.; Vinokhodova, A.; Vasylieva, G.; Nitchiporuk, I.; Ehmann, B.; Balazs, L.

    2012-01-01

    “Mars-105” experiment was executed in March-July 2009 in Moscow, at the Institute for Bio-Medical Problems (IBMP) with participation of European Space Agency (ESA) to simulate some specific conditions of future piloted Mars mission. In the last 35 days of isolation, in order to simulate autonomous flight conditions, some serious restrictions were established for the crew resupply and communication with Mission Control (MC). The objective of the study was to investigate psychophysiological and behavioral aspects (communication) of adaptation during this period of “high autonomy”. We used computerized analysis of the crew written daily reports to calculate the frequencies of utilization of certain semantic units, expressing different psychological functions. To estimate the level of psycho-physiological stress, we measured the concentration of urinal cortisol once in two weeks. To investigate psycho-emotional state, we used the questionnaire SAN, estimating Mood, Activity and Health once in two weeks.During the simulation of autonomous flight, we found out the different tendencies of communicative behavior. One group of subjects demonstrated the tendency to “activation and self-government” under “high autonomy” conditions. The other subjects continued to use communicative strategy that we called “closing the communication channel”. “Active” communication strategy was accompanied by increasing in subjective scores of mood and activity. The subjects, whose communication strategy was attributed as “closing”, demonstrated the considerably lower subjective scores of mood and activity. Period of high autonomy causes specific changes in communication strategies of the isolated crew.

  8. [The amino acid composition of blood serum of harp seal pups in the period of adaptation to captivity].

    PubMed

    Erokhina, I A

    1998-01-01

    It is cited results of investigation of amino acid composition of blood serum of harp seal pups in the first days after catch adaptation in conditions of oceanarium. It is shown that changes of amino acid composition are most expressed in the first ten-day period of observation and manifest itself by increase of free amino acid concentration at the expense of their endogenous entrance in blood. At the same time it was detected amino acid imbalance which is conditioned by stress of animals. Results of investigation witness intensification of protein catabolism under conditions of stress. Because of it it is necessary to correlate protein metabolism for prophylaxis of hypotrophy seal pups.

  9. Unique failure behavior of metal/composite aircraft structural components under crash type loads

    NASA Technical Reports Server (NTRS)

    Carden, Huey D.

    1990-01-01

    Failure behavior results are presented on some of the crash dynamics research conducted with concepts of aircraft elements and substructure which have not necessarily been designed or optimized for energy absorption or crash loading considerations. To achieve desired new designs which incorporate improved energy absorption capabilities often requires an understanding of how more conventional designs behave under crash type loadings. Experimental and analytical data are presented which indicate some general trends in the failure behavior of a class of composite structures which include individual fuselage frames, skeleton subfloors with stringers and floor beams but without skin covering, and subfloors with skin added to the frame-stringer arrangement. Although the behavior is complex, a strong similarity in the static/dynamic failure behavior among these structures is illustrated through photographs of the experimental results and through analytical data of generic composite structural models. It is believed that the thread of similarity in behavior is telling the designer and dynamists a great deal about what to expect in the crash behavior of these structures and can guide designs for improving the energy absorption and crash behavior of such structures.

  10. Composite behavior analysis for video surveillance using hierarchical dynamic Bayesian networks

    NASA Astrophysics Data System (ADS)

    Cheng, Huanhuan; Shan, Yong; Wang, Runsheng

    2011-03-01

    Analyzing composite behaviors involving objects from multiple categories in surveillance videos is a challenging task due to the complicated relationships among human and objects. This paper presents a novel behavior analysis framework using a hierarchical dynamic Bayesian network (DBN) for video surveillance systems. The model is built for extracting objects' behaviors and their relationships by representing behaviors using spatial-temporal characteristics. The recognition of object behaviors is processed by the DBN at multiple levels: features of objects at low level, objects and their relationships at middle level, and event at high level, where event refers to behaviors of a single type object as well as behaviors consisting of several types of objects such as ``a person getting in a car.'' Furthermore, to reduce the complexity, a simple model selection criterion is addressed, by which the appropriated model is picked out from a pool of candidate models. Experiments are shown to demonstrate that the proposed framework could efficiently recognize and semantically describe composite object and human activities in surveillance videos.

  11. Matrix cracking and creep behavior of monolithic zircon and zircon silicon carbide fiber composites

    NASA Astrophysics Data System (ADS)

    Anandakumar, Umashankar

    In this study, the first matrix cracking behavior and creep behavior of zircon matrix silicon carbide fiber composites were studied, together with the fracture and creep behavior of the monolithic zircon. These behaviors are of engineering and scientific importance, and the study was aimed at understanding the deformation mechanisms at elevated temperatures. The first matrix cracking behavior of zircon matrix uniaxially reinforced with silicon carbide fiber (SCS-6) composites and failure behavior of monolithic zircon were studied as a function of temperature (25°C, 500°C, and 1200°C) and crack length in three point bending mode. A modified vicker's indentation technique was used to vary the initial crack length in monolithic and composite samples. The interfacial shear strength was measured at these temperatures from matrix crack saturation spacing. The composites exhibited steady state and non steady state behaviors at the three different temperatures as predicted by theoretical models, while the failure stress of zircon decreased with increasing stress. The intrinsic properties of the composites were used to numerically determine the results predicted by three different matrix cracking models based on a fracture mechanics approach. The analysis showed that the model based on crack bridging analysis was valid at 25°C and 500°C, while a model based on statistical fiber failure was valid at 1200°C. Microstructural studies showed that fiber failure in the crack wake occurred at or below the matrix cracking stress at 1200°C, and no fiber failure occurred at the other two temperatures, which validated the results predicted by the theoretical models. Also, it was shown that the interfacial shear stress corresponding to debonding determined the matrix cracking stress, and not the frictional shear stress. This study showed for the first time, the steady state and non-steady state matrix cracking behavior at elevated temperatures, the difference in behavior between

  12. Teaching Paragraph Composition to Students with Emotional/Behavioral Disorders Using the Simultaneous Prompting Procedure

    ERIC Educational Resources Information Center

    Hudson, Tina Marlene; Hinkson-Lee, Kim; Collins, Belva

    2013-01-01

    The purpose of this study was to examine the effectiveness of the simultaneous prompting procedure in teaching paragraph composition to 4, 5th grade students identified with emotional behavioral disorder (EBD) and attention-deficit hyperactivity disorder (ADHD). The instructor taught students how to construct and proofread a 5-sentence paragraph…

  13. Treatment of addiction and addiction-related behavior using a composition of topiramate

    DOEpatents

    Dewey, Stephen L.; Brodie, Jonathan D.; Ashby, Jr., Charles R.

    2005-06-14

    The present invention relates to the use of a composition that increases central nervous system GABA levels in a mammal, for the treatment of addiction to drugs of abuse and modification of behavior associated with addiction to drugs of abuse in said mammal.

  14. Adaptive Behavior in Autism and Pervasive Developmental Disorder-Not Otherwise Specified: Microanalysis of Scores on the Vineland Adaptive Behavior Scales

    ERIC Educational Resources Information Center

    Paul, Rhea; Miles, Stephanie; Cicchetti, Domenic; Sparrow, Sara; Klin, Ami; Volkmar, Fred; Coflin, Megan; Booker, Shelley

    2004-01-01

    The purpose of this study is to provide a microanalysis of differences in adaptive functioning seen between well-matched groups of school-aged children with autism and those diagnosed as having Pervasive Developmental Disorder-Not Otherwise Specified, all of whom functioned in the mild to moderate range of intellectual impairment. Findings…

  15. Tensile behavior of MWCNT enhanced glass fiber reinforced polymeric composites at various crosshead speeds

    NASA Astrophysics Data System (ADS)

    Mahato, K. K.; Rathore, D. K.; Prusty, R. K.; Dutta, K.; Ray, B. C.

    2017-02-01

    Fiber reinforced polymeric (FRP) composite materials are subjected to different range of crosshead speeds during their in-service life. The work has been focused to investigate the effect of carbon nanotube (CNT) addition in glass fiber reinforced polymer (GFRP) composite on tensile behavior. The Control GFRP composites and CNT modified composites were tested at different crosshead speeds viz. 1, 10, 100 mm/min. CNT modified matrix was processed with epoxy as a matrix materials and multi-walled carbon nanotube (MWCNT) as a filler with different MWCNT content (i.e. 0.1, 0.3 and 0.5 wt. %). Increase in the CNT content upto 0.3% the tensile strength increasing for all the crosshead speeds as compared to the control GFRP composite. The tensile strength are dependent on the CNT content in GFRP composite. It has been observed that addition of 0.1% CNT and 0.3% CNT enhanced the tensile strength by 6.11% and 9.28% respectively than control GFRP composite. The tensile modulus is found to be mostly unaffected on an optimum CNT content in the GFRP composite. The tensile strength of control GFRP and all CNT modified GFRP composites were found to be crosshead speed sensitive and increased with increasing crosshead speeds in the aforesaid loadings. However, slight decrease in tensile modulus was observed with addition of CNT due to agglomeration of the CNT in the polymer matrix composites. The DSC analysis was also carried out to understand the effect of the CNT content on the glass transition temperature (Tg) of GFRP composites. Different failure patterns of GFRP composite tested at 1, 10, and 100 mm/min crosshead speeds were identified.

  16. Fatigue Crack Propagation Behavior According Tofiber Arraying Direction for Load Direction Inwoven CFRP Composite

    NASA Astrophysics Data System (ADS)

    Choi, Jung-Hun; Kang, Min-Sung; Koo, Jae-Mean; Seok, Chang-Sung; Kim, Hyung-Ick

    The fatigue crack propagation of CFRP (carbon fiber reinforced composite material) laminates is of current interest, particularly with regard to their durability under fatigue loading. Recently, carbon fiber reinforced composite materials (Woven fabric) are widely used in various fields of engineering because of its advanced properties. Then, many researchers have studied woven fabric CFRP materials but fatigue crack propagation behaviors for composites have not been still standardized . It shows the different crack propagation behavior according to load and fiber direction. Therefore, there is a need to consider fatigue crack propagation behavior in conformity with fiber arraying direction to load direction at designing structure using woven CFRP materials. In this study, therefore, the fatigue crack propagation for plain woven CFRP composite materials was investigated under two different fiber array direction (fiber arraying direction to load : 0°, 45°). Fatigue crack propagation tests of the woven CFRP composite were conducted under sinusoidal wave-form with stress ratios of 0.3 at a frequency of 10Hz, respectively. As a result of test, fatigue crack propagation rates (da/dN) were plotted against the stress-intensity factor amplitude (ΔK) and other factor. Also we compared ΔK with other factor that considering in-plain anisotropy. All of tests of fatigue crack propagation were carried out under mode I opening loading by using compact tension specimens.

  17. Highly Dynamic and Adaptive Traffic Congestion Avoidance in Real-Time Inspired by Honey Bee Behavior

    NASA Astrophysics Data System (ADS)

    Wedde, Horst F.; Lehnhoff, Sebastian; van Bonn, Bernhard; Bay, Z.; Becker, S.; Böttcher, S.; Brunner, C.; Büscher, A.; Fürst, T.; Lazarescu, A. M.; Rotaru, E.; Senge, S.; Steinbach, B.; Yilmaz, F.; Zimmermann, T.

    Traffic congestions have become a major problem in metropolitan areas world-wide, within and between cities, to an extent where they make driving and transportation times largely unpredictable. Due to the highly dynamic character of congestion building and dissolving this phenomenon appears even to resist a formal treatment. Static approaches, and even more their global management, have proven counterproductive in practice. Given the latest progress in VANET technology and the remarkable commercially driven efforts like in the European C2C consortium, or the VSC Project in the US, allow meanwhile to tackle various aspects of traffic regulation through VANET communication. In this paper we introduce a novel, completely decentralized multi-agent routing algorithm (termed BeeJamA) which we have derived from the foraging behavior of honey bees. It is highly dynamic, adaptive, robust, and scalable, and it allows for both avoiding congestions, and minimizing traveling times to individual destinations. Vehicle guidance is provided well ahead of every intersection, depending on the individual speeds. Thus strict deadlines are imposed on, and respected by, the BeeJamA algorithm. We report on extensive simulation experiments which show the superior performance of BeeJamA over conventional approaches.

  18. Learning from experience: Event-related potential correlates of reward processing, neural adaptation, and behavioral choice

    PubMed Central

    Walsh, Matthew M.; Anderson, John R.

    2012-01-01

    To behave adaptively, we must learn from the consequences of our actions. Studies using event-related potentials (ERPs) have been informative with respect to the question of how such learning occurs. These studies have revealed a frontocentral negativity termed the feedback-related negativity (FRN) that appears after negative feedback. According to one prominent theory, the FRN tracks the difference between the values of actual and expected outcomes, or reward prediction errors. As such, the FRN provides a tool for studying reward valuation and decision making. We begin this review by examining the neural significance of the FRN. We then examine its functional significance. To understand the cognitive processes that occur when the FRN is generated, we explore variables that influence its appearance and amplitude. Specifically, we evaluate four hypotheses: (1) the FRN encodes a quantitative reward prediction error; (2) the FRN is evoked by outcomes and by stimuli that predict outcomes; (3) the FRN and behavior change with experience; and (4) the system that produces the FRN is maximally engaged by volitional actions. PMID:22683741

  19. Behavioral adaptation of young and older drivers to an intersection crossing advisory system.

    PubMed

    Dotzauer, Mandy; de Waard, Dick; Caljouw, Simone R; Pöhler, Gloria; Brouwer, Wiebo H

    2015-01-01

    An advanced driver assistance system (ADAS) provided information about the right of way regulation and safety to cross an upcoming intersection. Effects were studied in a longer-term study involving 18 healthy older drivers between the ages of 65 and 82 years and 18 healthy young drivers between the ages of 20 and 25 years. Participants repeatedly drove 25 km city routes in eight sessions on separate days over a period of two months in a driving simulator. In each age group, participants were randomly assigned to the control (no ADAS) and treatment (ADAS) group. The control group completed the whole experiment without the ADAS. The treatment group drove two sessions without (sessions 1 and 7) and six times with ADAS. Results indicate effects of ADAS on driving safety for young and older drivers, as intersection time and percentage of stops decreased, speed and critical intersection crossings increased, the number of crashes was lower for treatment groups than for control groups. The implications of results are discussed in terms of behavioral adaptation and safety.

  20. Adaptive Behavior Assessment System-II Parent/Primary Caregiver Form: Ages 0-5--Its Factor Structure and Other Implications for Practice

    ERIC Educational Resources Information Center

    Oakland, Thomas; Algina, James

    2011-01-01

    A child's acquisition of adaptive behavior and skills may constitute his or her most important goal during infancy and early childhood. In addition, adaptive behavior data often are required when making decisions under Part C of the 2004 Individuals With Disabilities Education Improvement Act. This study reports the results of a factor analysis of…

  1. A Comparative Study of the Preliminary Effects in the Levels of Adaptive Behaviors: Learning Program for the Development of Children with Autism (LPDCA)

    ERIC Educational Resources Information Center

    Shin, Sunwoo; Koh, Myung-sook; Yeo, Moon-Hwan

    2012-01-01

    The purpose of this study was to investigate preliminary intervention effects of the adaptive behavior on the autism intervention program known as the Learning Program for the Development of Children with Autism (LPDCA). The adaptive behavior scores of two groups of students with autism spectrum disorders (ASD) were compared, with one group…

  2. Factorial and Hierarchical Cluster Analysis of the Adaptive Behavior Scales (Part I & II) in a Population of Older People (50 Years +) with Severe Intellectual Impairment (Mental Handicap).

    ERIC Educational Resources Information Center

    Moss, S. C.; Hogg, J.

    1990-01-01

    Principal components analysis was employed on the Adaptive Behavior Scales with scores of 122 older (mean age 63.5) individuals with severe intellectual impairment living in England. The study found the structure of adaptive skills and interpersonal maladaptive behaviors similar to that found for younger retarded adults. Two factors, personal…

  3. Transient Creep Behavior of a Plain Woven SiC Fiber/SiC Matrix Composite

    NASA Astrophysics Data System (ADS)

    Bessho, Takayuki; Ogasawara, Toshio; Aoki, Takuya; Ishikawa, Takashi; Ochi, Yasuo

    The present work investigates the transient creep behavior of a plain woven Tyranno™ Lox-M (Si-Ti-C-O) fiber/SiC matrix composite at 1473K in air. Tensile creep tests were carried out under a constant load between 80 and 160MPa. A creep strain rate is generally represented by ɛ∝ σn with a constant stress exponent, however the stress exponent decreased with time for this composite material. Monotonic tensile tests were also conducted for loading rates of 0.03, 0.3, and 3kN/min in order to investigate the effect of creep strain on tensile stress/strain behavior. Based on the empirical transient creep equation and creep-hardening model, stress/strain curves under monotonic tensile loading were predicted. A good correlation was obtained between the predicted and measured composite stress/strain curves using strain-hardening model.

  4. Thermal and mechanical behavior of metal matrix and ceramic matrix composites

    NASA Technical Reports Server (NTRS)

    Kennedy, John M. (Editor); Moeller, Helen H. (Editor); Johnson, W. S. (Editor)

    1990-01-01

    The present conference discusses local stresses in metal-matrix composites (MMCs) subjected to thermal and mechanical loads, the computational simulation of high-temperature MMCs' cyclic behavior, an analysis of a ceramic-matrix composite (CMC) flexure specimen, and a plasticity analysis of fibrous composite laminates under thermomechanical loads. Also discussed are a comparison of methods for determining the fiber-matrix interface frictional stresses of CMCs, the monotonic and cyclic behavior of an SiC/calcium aluminosilicate CMC, the mechanical and thermal properties of an SiC particle-reinforced Al alloy MMC, the temperature-dependent tensile and shear response of a graphite-reinforced 6061 Al-alloy MMC, the fiber/matrix interface bonding strength of MMCs, and fatigue crack growth in an Al2O3 short fiber-reinforced Al-2Mg matrix MMC.

  5. [Change in the lipid composition of the inner mitochondrial membranes in rat organs during adaptation to heat].

    PubMed

    Zubareva, E V; Seferova, R I; Denisova, N A

    1991-01-01

    Under conditions of adaptation to heating lipid composition in mitochondrial membranes of rat inner tissues was altered as follows: an increase in relative concentration of plasmalogenous forms of phospholipids (kidney, heart) and in content of saturated fatty acids (liver tissue), a decrease in the index of fatty acids unsaturation and in the ratio of fatty acids omega-3/omega-6. The alterations observed enabled the membranes to keep sufficient amount of liquidity essential for functional activity of mitochondria in heating.

  6. Vineland Adaptive Behavior Scales: II Profile of Young Children with Autism Spectrum Disorder

    ERIC Educational Resources Information Center

    Yang, Sabrina; Paynter, Jessica M.; Gilmore, Linda

    2016-01-01

    Adaptive behaviour is a crucial area of assessment for individuals with Autism Spectrum Disorder (ASD). This study examined the adaptive behaviour profile of 77 young children with ASD using the Vineland-II, and analysed factors associated with adaptive functioning. Consistent with previous research with the original Vineland a distinct autism…

  7. Classification and adaptive behavior prediction of children with autism spectrum disorder based upon multivariate data analysis of markers of oxidative stress and DNA methylation

    PubMed Central

    Melnyk, Stepan; James, S. Jill; Hahn, Juergen

    2017-01-01

    The number of diagnosed cases of Autism Spectrum Disorders (ASD) has increased dramatically over the last four decades; however, there is still considerable debate regarding the underlying pathophysiology of ASD. This lack of biological knowledge restricts diagnoses to be made based on behavioral observations and psychometric tools. However, physiological measurements should support these behavioral diagnoses in the future in order to enable earlier and more accurate diagnoses. Stepping towards this goal of incorporating biochemical data into ASD diagnosis, this paper analyzes measurements of metabolite concentrations of the folate-dependent one-carbon metabolism and transulfuration pathways taken from blood samples of 83 participants with ASD and 76 age-matched neurotypical peers. Fisher Discriminant Analysis enables multivariate classification of the participants as on the spectrum or neurotypical which results in 96.1% of all neurotypical participants being correctly identified as such while still correctly identifying 97.6% of the ASD cohort. Furthermore, kernel partial least squares is used to predict adaptive behavior, as measured by the Vineland Adaptive Behavior Composite score, where measurement of five metabolites of the pathways was sufficient to predict the Vineland score with an R2 of 0.45 after cross-validation. This level of accuracy for classification as well as severity prediction far exceeds any other approach in this field and is a strong indicator that the metabolites under consideration are strongly correlated with an ASD diagnosis but also that the statistical analysis used here offers tremendous potential for extracting important information from complex biochemical data sets. PMID:28301476

  8. Classification and adaptive behavior prediction of children with autism spectrum disorder based upon multivariate data analysis of markers of oxidative stress and DNA methylation.

    PubMed

    Howsmon, Daniel P; Kruger, Uwe; Melnyk, Stepan; James, S Jill; Hahn, Juergen

    2017-03-01

    The number of diagnosed cases of Autism Spectrum Disorders (ASD) has increased dramatically over the last four decades; however, there is still considerable debate regarding the underlying pathophysiology of ASD. This lack of biological knowledge restricts diagnoses to be made based on behavioral observations and psychometric tools. However, physiological measurements should support these behavioral diagnoses in the future in order to enable earlier and more accurate diagnoses. Stepping towards this goal of incorporating biochemical data into ASD diagnosis, this paper analyzes measurements of metabolite concentrations of the folate-dependent one-carbon metabolism and transulfuration pathways taken from blood samples of 83 participants with ASD and 76 age-matched neurotypical peers. Fisher Discriminant Analysis enables multivariate classification of the participants as on the spectrum or neurotypical which results in 96.1% of all neurotypical participants being correctly identified as such while still correctly identifying 97.6% of the ASD cohort. Furthermore, kernel partial least squares is used to predict adaptive behavior, as measured by the Vineland Adaptive Behavior Composite score, where measurement of five metabolites of the pathways was sufficient to predict the Vineland score with an R2 of 0.45 after cross-validation. This level of accuracy for classification as well as severity prediction far exceeds any other approach in this field and is a strong indicator that the metabolites under consideration are strongly correlated with an ASD diagnosis but also that the statistical analysis used here offers tremendous potential for extracting important information from complex biochemical data sets.

  9. Densification Behavior and Performances of C/C Composites Derived from Various Carbon Matrix Precursors

    NASA Astrophysics Data System (ADS)

    Shao, H. C.; Xia, H. Y.; Liu, G. W.; Qiao, G. J.; Xiao, Z. C.; Su, J. M.; Zhang, X. H.; Li, Y. J.

    2014-01-01

    Three types of carbon/carbon (C/C) composites were manufactured by densifying the needled carbon fiber preform through resin and pitch impregnation/carbonization repeatedly, as well as propylene pyrolysis by chemical vapor infiltration plus carbonization after the resin impregnation/carbonization. The densification behavior and performances (involving electric, thermal, and mechanical properties, as well as impurity) of the C/C composites were investigated systematically. The results show that besides the processing and testing conditions, the electric resistivity, thermal conductivity (TC), coefficient of thermal expansion (CTE), strength, and fracture, as well as impurity content and composition of the C/C composites were closely related to the fiber orientation, interfacial bonding between carbon fiber and carbon matrix, material characteristics of the three precursors and the resulting matrix carbons. In particular, the resin-carbon matrix C/C (RC/C) composites had the highest electric resistivity, tensile, and flexural strength, as well as impurity content. Meanwhile, the pitch-carbon matrix C/C (PC/C) composites possessed the highest TC and CTE in the parallel and vertical direction. And most of the performances of pyro-carbon/resin carbon matrix C/C composites were between those of the RC/C and PC/C composites except the impurity content.

  10. The influence of FRCs reinforcement on marginal adaptation of CAD/CAM composite resin endocrowns after simulated fatigue loading.

    PubMed

    Rocca, Giovanni Tommaso; Saratti, Carlo Massimo; Poncet, Antoine; Feilzer, Albert J; Krejci, Ivo

    2016-05-01

    To evaluate the marginal adaptation of endodontically treated molars restored with CAD/CAM composite resin endocrowns either with or without reinforcement by fibre reinforced composites (FRCs), used in different configurations. 32 human endodontically treated molars were cut 2 mm over the CEJ. Two interproximal boxes were created with the margins located 1 mm below the CEJ (distal box) and 1 mm over the CEJ (mesial box). All specimens were divided in four groups (n = 8). The pulp chamber was filled with: group 1 (control), hybrid resin composite (G-aenial Posterior, GC); group 2, as group 1 but covered by 3 meshes of E-glass fibres (EverStick NET, Stick Tech); group 3, FRC resin (EverX Posterior, GC); group 4, as group 3 but covered by 3 meshes of E-glass fibres. The crowns of all teeth were restored with CAD/CAM composite resin endocrowns (LAVA Ultimate, 3M). All specimens were thermo-mechanically loaded in a computer-controlled chewing machine (600,000 cycles, 1.6 Hz, 49 N and simultaneously 1500 thermo-cycles, 60 s, 5-55 °C). Marginal analysis before and after the loading was carried out on epoxy replicas by SEM at 200× magnification. For all the groups, the percentage values of perfect marginal adaptation after loading were always significantly lower than before loading (p < 0.05). The marginal adaptation before and after loading was not significantly different between the experimental groups (p > 0.05). Within the limitations of this in vitro study, the use of FRCs to reinforce the pulp chamber of devitalized molars restored with CAD/CAM composite resin restorations did not significantly influenced their marginal quality.

  11. Adaptive Optics with a Liquid-Crystal-on-Silicon Spatial Light Modulator and Its Behavior in Retinal Imaging

    NASA Astrophysics Data System (ADS)

    Shirai, Tomohiro; Takeno, Kohei; Arimoto, Hidenobu; Furukawa, Hiromitsu

    2009-07-01

    An adaptive optics system with a brand-new device of a liquid-crystal-on-silicon (LCOS) spatial light modulator (SLM) and its behavior in in vivo imaging of the human retina are described. We confirmed by experiments that closed-loop correction of ocular aberrations of the subject's eye was successfully achieved at the rate of 16.7 Hz in our system to obtain a clear retinal image in real time. The result suggests that an LCOS SLM is one of the promising candidates for a wavefront corrector in a prospective commercial ophthalmic instrument with adaptive optics.

  12. Tensile behavior of glass/ceramic composite materials at elevated temperatures

    NASA Technical Reports Server (NTRS)

    Mandell, J. F.; Grande, D. H.; Jacobs, J.

    1987-01-01

    This paper describes the tensile behavior of high-temperature composite materials containing continuous Nicalon ceramic fiber reinforcement and glass and glass/ceramic matrices. The longitudinal properties of these materials can approach theoretical expectations for brittle matrix composites, failing at a strength and ultimate strain level consistent with those of the fibers. The brittle, high-modulus matrices result in a nonlinear stress-strain curve due to the onset of stable matrix cracking at 10 to 30 percent of the fiber strain to failure, and at strains below this range in off-axis plies. Current fibers and matrices can provide attractive properties well above 1000 C, but composites experience embrittlement in oxidizing atmospheres at 800 to 1000 C due to oxidation of a carbon interface reaction layer.The oxidation effect greatly increases the interface bond strength, causing composite embrittlement.

  13. Environmental effects and viscoelastic behavior of laminated graphite/epoxy composites

    NASA Technical Reports Server (NTRS)

    Dillard, D. A.; Morris, D. H.; Brinson, H. F.

    1983-01-01

    Primarily because of the polymeric matrix, graphite/epoxy composites are viscoelastic materials which exhibit creep and delayed failures. Guided by the time-temperature superposition principle, the authors are developing accelerated characterization techniques to predict the long term compliance behavior and creep rupture strength of composite materials based on short term tests at elevated temperatures. The effect of a post-cure cycle on the compliance and creep rupture strength of composite materials is discussed. The Zhurkov type failure law is applied to experimental creep rupture data of a typical laminate and is shown to correlate the data. A beneficial mechanical strengthening effect is described which significantly affects the failure strengths of specimens which have been under creep loading for a period of time. This aging effect is reversible if the specimen is allowed to recover before being loaded to failure. Other environmental aspects of composite materials are also reviewed.

  14. R-Curve Behavior of Si3N4/BNNT Composites

    NASA Astrophysics Data System (ADS)

    Yu, Hang-Hai; Wang, Shou-Ren; Yang, Li-Ying

    2013-10-01

    The crack propagation rsistance behavior of Si3N4 ceramics reinforced by boron nitride nanotubes (BNNT) has been discussed in the work. And, bending strength and fracture toughness of Si3N4/BNNT composites were tested by three point bending method. It is shown that crack propagation resistance of BNNT/Si3N4 composites is increased distinctly owing to addition of BNNT. It is attributed to the pinning and bridging roles of BNNT. One kind of mathematical model was constructed for calculating crack propagation resistance of Si3N4 ceramics and BNNT/Si3N4 composites. Crack resistance curve ( R-Curve) of Si3N4 ceramics and BNNT/Si3N4 composites was also calculated. Crack propagation of them was simulated using finite element methods. The results show that strong shielding area is formed in crack tip owing to existence of BNNT and crack propagation is prevented by strong stress shielding roles.

  15. Measurement of the internal adaptation of resin composites using micro-CT and its correlation with polymerization shrinkage.

    PubMed

    Kim, H J; Park, S H

    2014-01-01

    In the present study, the internal adaptation of dentin-composite interfaces with various resin composite materials under conditions of thermomechanical loading was analyzed nondestructively using micro-computed tomography (micro-CT), and these results were compared with analyses of microgaps after sectioning. Additionally, the correlation of internal adaptation with polymerization shrinkage strain and stress was evaluated. Four nonflowable resins, Gradia Direct (GD), Filtek P90 (P9), Filtek Z350 (Z3), and Charisma (CH), and two flowable resins, SDR (SD) and Tetric N-Flow (TF) were used. First, the polymerization shrinkage strain and stress were measured. Then, Class I cavities were prepared in 48 premolars. They were divided randomly into six groups, and the cavities were filled with composites using XP bond. To evaluate the internal adaptation, tooth specimens were immersed in a 25% silver nitrate solution, and micro-CT analysis was performed before and after thermomechanical loading. The silver nitrate penetration (%SP) was measured. After buccolingual sectioning and rhodamine penetration of the specimen, the rhodamine penetration (%RP) was measured using a stereo-microscope. One-way analysis of variance was then used to compare the polymerization shrinkage strain, stress, %SP, and %RP among the groups at a 95% confidence level. A paired t-test was used to compare the %SP before and after thermomechanical loading. Pearson correlation analysis was used to compare the correlation between polymerization shrinkage strain/stress and %SP or %RP to a 95% confidence level. Evaluation of the polymerization shrinkage strain demonstrated that P9 < Z3 ≤ GD < CH ≤ SD < TF (p<0.05); similarly, evaluation of the polymerization shrinkage stress showed that P9 ≤ GD ≤ Z3 ≤ CH ≤ SD < TF (p<0.05). The %SP showed that P9 ≤ GD ≤ Z3 < CH ≤ SD < TF (p<0.05) before loading and that P9 ≤ GD ≤ Z3 ≤ CH ≤ SD < TF (p<0.05) after loading. There was a significant

  16. Mechanical properties and crystallization behavior of hydroxyapatite/poly(butylenes succinate) composites.

    PubMed

    Guo, Wenmin; Zhang, Yihe; Zhang, Wei

    2013-09-01

    Biodegradable synthetic polymers have attracted much attention nowadays, and more and more researches have been done on biodegradable polymers due to their excellent mechanical properties, biocompatibility, and biodegradability. In this work, hydroxyapatite (HA) particles were melt-mixing with poly (butylenes succinate) (PBS) to prepare the material, which could be used in the biomedical industry. To develop high-performance PBS for cryogenic engineering applications, it is necessary to investigate the cryogenic mechanical properties and crystallization behavior of HA/PBS composites. Cryogenic mechanical behaviors of the composites were studied in terms of tensile and impact strength at the glass transition temperature (-30°C) and compared to their corresponding behaviors at room temperature. With the increase of HA content, the crystallization of HA/PBS composites decreased and crystallization onset temperature shifted to a lower temperature. The diameter of spherulites increased at first and decreased with a further HA content. At the same time, the crystallization rate became slow when the HA content was no more than 15wt% and increased when HA content reached 20wt%. In all, the results we obtained demonstrate that HA/PBS composites reveal a better tensile strength at -30°C in contrast to the strength at room temperature. HA particles with different amount affect the crystallization of PBS in different ways.

  17. How do people's perceptions and climatic disaster experiences influence their daily behaviors regarding adaptation to climate change? - A case study among young generations.

    PubMed

    Deng, Ying; Wang, Ming; Yousefpour, Rasoul

    2017-03-01

    Adaptation is a commonly applied strategy used to address individual behavior changes, in response to climate change. However, in-depth, evidence-based investigations of the relationships among individual perceptions, climatic disaster experiences, and daily behaviors regarding adaptation to climate change remain to be conducted. We obtained survey data from 488 respondents in southwestern China, a region prone to frequent and severe droughts, to assess factors that influence adaptive behaviors and to identify their pathways. We applied Construal Level Theory (CLT) and the Theory of Planned Behavior (TPB) to differentiate between respondents' high-level abstract construals and their low-level concrete construals. We analyzed the influences of these two levels of perception, combined with drought experiences on water-saving behaviors. We developed a structural equation model to estimate the correlation coefficients of the latent and observed variables in the structural process linked to the respondents' adaptive behaviors. The results found that a concrete perception of saving water plays a more significant part than an abstract perception of climate change in prompting specific adaptive behaviors. Improving public perceptions of climate change might increase the desirability of adaptation, whereas improving perceptions of water saving might increase the feasibility of implementing adaptive measures. Experience influenced individual behaviors, but that influence was indirect through its effects on perceptions.

  18. Time dependent behavior of a graphite/thermoplastic composite and the effects of stress and physical aging

    NASA Technical Reports Server (NTRS)

    Gates, Thomas S.; Feldman, Mark

    1993-01-01

    Two complimentary studies were performed to determine the effects of stress and physical aging on the matrix dominated time dependent properties of IM7/8320 composite. The first of these studies, experimental in nature, used isothermal tensile creep/aging test techniques developed for polymers and adapted them for testing of the composite material. From these tests, the time dependent transverse (S22) and shear (S66) compliance's for an orthotropic plate were found from short term creep compliance measurements at constant, sub-T(sub g) temperatures. These compliance terms were shown to be affected by physical aging. Aging time shift factors and shift rates were found to be a function of temperature and applied stress. The second part of the study relied upon isothermal uniaxial tension tests of IM7/8320 to determine the effects of physical aging on the nonlinear material behavior at elevated temperature. An elastic/viscoplastic constitutive model was used to quantify the effects of aging on the rate-independent plastic and rate-dependent viscoplastic response. Sensitivity of the material constants required by the model to aging time were determined for aging times up to 65 hours. Verification of the analytical model indicated that the effects of prior aging on the nonlinear stress/strain/time data of matrix dominated laminates can be predicted.

  19. Behavior of plywood and fiberglass steel composite tube structures subjected to impact loading

    NASA Astrophysics Data System (ADS)

    Armaghani, Seyamend Bilind

    Paratransit buses are custom built as the major vehicle manufacturer produces the custom built passenger cage installed on the chassis for the Paratransit bus. In order for these Paratransit bus members to be sufficient, they have to be evaluated for crashworthiness and energy absorption. This has prompted Florida Department of Transportation (FDOT) to fund research for the safety evaluation of Paratransit busses consisting of crash and safety analysis. There has been a large body of research done on steel subjected to static loads, but more research is needed for steel applied under dynamic loading and high speeds in order to improve crashworthiness in events such as rollovers and side impacts. Bare steel Hollow Structural Section (HSS) tubing are used a lot as structural members of Paratransit buses because of their lightness and progressive buckling under loading. The research will be conducted on quantifying the tubing's behavior under bending by conducting static three point bending and impact loading tests. In addition to the bare tubing, plywood and fiberglass composites are investigated because they are both strong and lightweight and their behavior under dynamic loading hasn't been quantified. As a result, the main purpose of this research is to quantify the differences between the dynamic and static behavior of plywood steel composite and fiberglass steel composite tubing and compare these findings with those of bare steel tubing. The differences will be quantified using detailed and thorough experiments that will examine the composites behavior under both static and dynamic loading. These tests will determine if there are any advantages of using the composite materials and thus allow for recommendations to be made to the FDOT with the goal of improving the safety of Paratransit busses. Tensile tests were conducted to determine the material properties of the tested specimens. Before the static and dynamic experiments are run to investigate the differences

  20. Research on Tribological Behavior of PEEK and Glass Fiber Reinforced PEEK Composite

    NASA Astrophysics Data System (ADS)

    Li, E. Z.; Guo, W. L.; Wang, H. D.; Xu, B. S.; Liu, X. T.

    The tribological behaviors of pure polyetheretherketone (PEEK) and PEEK composites reinforced by 30wt% short glass fibers (GF) were comparatively evaluated on a ball-on-disc configuration at room temperature. The effects of applied load and sliding time on the friction coefficient and wear loss of the GF/PEEK were examined. The mechanical property, morphology and thermal performance of the composite were studied. The results indicated that the friction coefficient and wear loss of the composite increased gradually and tended to be a stable state as the increase of applied load and sliding time. The GF/PEEK has an excellent wear resistance, compared with PEEK. The SEM and EDS indicated that the short glass-fibers were extruded from the composite rather than pulverized into the composite. Compared with that of pure PEEK, the thermal decomposition temperature of GF/PEEK composite had an increase of 75 °C. The tensile strength and flexural strength of the composite were increased by 64% and 66%, respectively.