111 research outputs found

    High-resolution imaging of elastic properties using harmonic cantilevers

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    We present a micromachined scanning probe cantilever, in which a specific higher-order flexural mode is designed to be resonant at an exact integer multiple of the fundamental resonance frequency. We have fabricated such cantilevers by reducing the stiffness of the third order flexural mode relative to the fundamental mode, and we have demonstrated that these cantilevers enable sensing of non-linear mechanical interactions between the atomically sharp tip at the free end of the cantilever and a surface with unknown mechanical properties in tapping-mode atomic force microscopy. Images of surfaces with large topographical variations show that for such samples harmonic imaging has better resolution than standard tapping-mode imaging. Ā© 2003 Elsevier B.V. All rights reserved

    Harmonic cantilevers for nanomechanical sensing of elastic properties

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    We present a micromachined scanning probe cantilever, in which a specific higher order flexural mode is designed to be resonant at an exact integer multiple of the fundamental resonance frequency. We have demonstrated that such cantilevers enable sensing of nonlinear mechanical interactions between the atomically sharp tip at the free end of the cantilever and a surface with unknown mechanical properties in tapping-mode atomic force microscopy. Ā© 2003 IEEE

    The science of choice: an introduction

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    Introduction In October 2015, around 30 scholars convened at the Max Planck Institute for Demographic Research (MPIDR) in Rostock to discuss: (a) how individuals and families make decisions about marriage, child-birth, migration, retirement, and other transitions in the life course; and (b) how these decision processes can be operationalized in demographic models. The workshop was organized by the Scientific Panel on Microsimulation and Agent-Based Modelling con- vened by the International Union for the Scientific Study of Population (IUSSP) and by MPIDR. The report of this ā€˜Science of choiceā€™ workshop and the papers presented are available from the workshopā€™s website (see IUSSP 2015). The five papers included in this Supplement are revised versions of papers presented at the workshop in Rostock

    An Evaluation of Parent Preference for Prompting Procedures

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    Parent participation in intervention can enhance intervention efficacy and promote generalization of skills across settings. Thus, parents should be trained to implement behavioral interventions. The purpose of the current investigation was to evaluate parent preference for and acceptability of 3 commonly used prompting procedures. We trained parents of children with disabilities to use 3 empirically validated prompting strategies (i.e., leastā€toā€most, mostā€toā€least, and a progressiveā€prompt delay). Once the parent reached the mastery criteria with each prompting procedure, we evaluated his/her preference for each of the procedures using a concurrentā€chains arrangement. We also measured treatment acceptability of all procedures throughout the study. All participants met the mastery criteria for each of the prompting procedures and showed a preference for leastā€toā€most prompting. Results suggest parents\u27 acceptability of procedures prior to training were different than posttraining/postā€child practice. In addition, acceptability rating scores obtained at the end of the investigation corresponded to preference of intervention during the concurrentā€chains arrangement. The results demonstrate the benefits of objective measures for studying preference for behavioral, skillā€acquisition procedures

    A Critical Review on the Structural Health Monitoring Methods of the Composite Wind Turbine Blades

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    With increasing turbine size, monitoring of blades becomes increasingly im-portant, in order to prevent catastrophic damages and unnecessary mainte-nance, minimize the downtime and labor cost and improving the safety is-sues and reliability. The present work provides a review and classification of various structural health monitoring (SHM) methods as strain measurement utilizing optical fiber sensors and Fiber Bragg Gratings (FBGā€™s), active/ pas-sive acoustic emission method, vibrationā€’based method, thermal imaging method and ultrasonic methods, based on the recent investigations and prom-ising novel techniques. Since accuracy, comprehensiveness and cost-effectiveness are the fundamental parameters in selecting the SHM method, a systematically summarized investigation encompassing methods capabilities/ limitations and sensors types, is needed. Furthermore, the damages which are included in the present work are fiber breakage, matrix cracking, delamina-tion, fiber debonding, crack opening at leading/ trailing edge and ice accre-tion. Taking into account the types of the sensors relevant to different SHM methods, the advantages/ capabilities and disadvantages/ limitations of repre-sented methods are nominated and analyzed

    Write, draw, show, and tell: a child-centred dual methodology to explore perceptions of out-of-school physical activity

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    Background Research to increase childrenā€™s physical activity and inform intervention design has, to date, largely underrepresented childrenā€™s voices. Further, research has been limited to singular qualitative methods that overlook childrenā€™s varied linguistic ability and interaction preference. The aim of this study was to use a novel combination of qualitative techniques to explore childrenā€™s current views, experiences and perceptions of out-of-school physical activity as well as offering formative opinion about future intervention design. Methods Write, draw, show and tell (WDST) groups were conducted with 35 children aged 10ā€“11 years from 7 primary schools. Data were analysed through a deductive and inductive process, firstly using the Youth Physical Activity Promotion Model as a thematic framework, and then inductively to enable emergent themes to be further explored. Pen profiles were constructed representing key emergent themes. Results The WDST combination of qualitative techniques generated complimentary interconnected data which both confirmed and uncovered new insights into factors relevant to childrenā€™s out-of-school physical activity. Physical activity was most frequently associated with organised sports. Fun, enjoyment, competence, and physical activity provision were all important predictors of childrenā€™s out-of-school physical activity. Paradoxically, parents served as both significant enablers (i.e. encouragement) and barriers (i.e. restricting participation) to physical activity participation. Some of these key findings would have otherwise remained hidden when compared to more traditional singular methods based approaches. Conclusions Parents are in a unique position to promote health promoting behaviours serving as role models, physical activity gatekeepers and choice architects. Given the strong socialising effect parents have on childrenā€™s physical activity, family-based physical activity intervention may offer a promising alternative compared to traditional school-based approaches. Parents' qualitative input is important to supplement childrenā€™s voices and inform future family-based intervention design. The WDST method developed here is an inclusive, interactive and child-centred methodology which facilitates the exploration of a wide range of topics and enhances data credibility

    Spotting the enemy within: Targeted silencing of foreign DNA in mammalian genomes by the KrĆ¼ppel-associated box zinc finger protein family

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    High-resolution imaging of elastic properties using harmonic cantilevers

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    Cataloged from PDF version of article.We present a micromachined scanning probe cantilever, in which a specific higher-order flexural mode is designed to be resonant at an exact integer multiple of the fundamental resonance frequency. We have fabricated such cantilevers by reducing the stiffness of the third order flexural mode relative to the fundamental mode, and we have demonstrated that these cantilevers enable sensing of non-linear mechanical interactions between the atomically sharp tip at the free end of the cantilever and a surface with unknown mechanical properties in tapping-mode atomic force microscopy. Images of surfaces with large topographical variations show that for such samples harmonic imaging has better resolution than standard tapping-mode imaging. Ā© 2003 Elsevier B.V. All rights reserved
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