1,721,679 research outputs found
Bulk-wave ultrasonic propagation imagers
No full textLaser-based ultrasound systems are described that utilize the ultrasonic bulk-wave sensing to detect the damages and flaws in the aerospace structures. These systems apply pulse-echo or through transmission methods to detect longitudinal through-the-thickness bulk-waves. These thermoelastic waves are generated using Q-switched laser and non-contact sensing is performed using a laser Doppler vibrometer (LDV). Laser-based raster scanning is performed by either two-axis translation stage for linear-scanning or galvanometer-based laser mirror scanner for angular-scanning. In all ultrasonic propagation imagers, the ultrasonic data is captured and processed in real-time and the ultrasonic propagation can be visualized during scanning. The scanning speed can go up to 1.8 kHz for two-axis linear translation stage based B-UPIs and 10 kHz for galvanometer-based laser mirror scanners. In contrast with the other available ultrasound systems, these systems have the advantage of high-speed, non-contact, real-time, and non-destructive inspection. In this paper, the description of all bulk-wave ultrasonic imagers (B-UPIs) are presented and their advantages are discussed. Experiments are performed with these system on various structures to proof the integrity of their results. The C-scan results produced from non-dispersive, through-the-thickness, bulk-wave detection show good agreement in detection of structural variances and damage location in all inspected structures. These results show that bulk-wave UPIs can be used for in-situ NDE of engineering structures
On Intrinsic Safety of Soft Robots
No full textThe rapidly growing field of soft robotics owes its success to the vast vistas of possibilities they promise. They may be utilized as standalone systems or work in harmony with the existing robotic technologies. Being based on soft and/or flexible materials, soft robots have usually high dexterity and, at the same time, they are also often considered “intrinsically safe.” This is generally true and soft-bodied robots can be considered safer from a mechanical point of view, but this is sometimes improperly used. The identification of possible safety loopholes in soft robots is the subject of this paper. After a general overview of safety in robotics, we reported an overview of the main sources of unsafe conditions that may arise by the use of soft robotics technologies. Safety aspects are discussed in three categories: quasi-static, dynamic, and material failure. Some safety factors exclusive to soft robots such as whiplash-like effect and energy stored in highly strained elements are also introduced. Measures to avoid such unsafe conditions are presented such as establishing operational limits and introduction of inspection regimes and arrest systems
Human resource practices and turnover intentions: A study of the hotel industry in Malaysia / Syed Haider Ali Shah
Full text linkThis study is an attempt to examine and incorporate HR practices and its relationship with turnover intentions. Moreover, there is a gap to link such HR practices with talent engagement, affective commitment and their outcomes. The first objective of the study is to investigate the impact of HR practices in reducing turnover intentions. The second objective is to examine the effect of HR practices on turnover intentions through mediating role of talent engagement (job engagement & organization engagement). The third objective is to analyze the mediating role of affective commitment between HR practices and turnover intentions. Based on the social exchange theory, an integrated model with three bundle of HR practices (motivation enhancing, empowerment enhancing, and skills enhancing) predicting variables, three mediating variables (job engagement, organization engagement and affective commitment) and one dependent variable, turnover intentions, is examined in this study. First, relevant dimensions of HR practices are identified from literature, where 16 dimensions of these three HR practices are selected with the help of expert survey. Based on this, the study develops a close ended questionnaire. Data was collected from 51 hotels (three star, four star and five star) which are registered with Malaysia Association of Hotels, 2014. The respondents (the line and middle line manages) are identified as the locus of talent resulting in a total of 425 managers with the response rate of 75%. This study applied the structural equation modeling technique to investigate the direct effects of HR practices (overall and dimensions) and indirect effects (through talent engagement and affective commitment) on turnover intentions. The results reveal a significant negative effect of HR practices on turnover intentions. Likewise, findings showed the mediating role of talent engagement and affective commitment between HR practices and turnover intentions. In analyzing the effects of individual HR practices, the study concludes that i) motivation enhancing practices negatively effect the turnover intentions, ii) empowerment enhancing practices negatively effect the turnover intentions and, iii) skills enhancing practices positively effect on turnover intentions. This study classified and developed three bundles of HR practices which adds value to the existing body of knowledge. Moreover, before bundling the HR practices, it is necessary to consider its individual effects on turnover intentions instead of only aggregate HR practices. This study highlights the need of careful selection of skills enhancing practices with company specific training practices. Further, this empirical study has focused on the managerial level which is considered as locus of talent. This research contributes to the existing literature of HRM on managerial level rather than general employee turnover. In addition to empirical progress in the existing knowledge, this study provides the application of this proposed model in hotels in Malaysia. Therefore, hotel management may introduce intervention strategies in the form of equipping talents with the necessary meaningful job engagement and organizational engagement. Moreover, hotel management could view engagement as a broad organizational and cultural strategy. Hence, top management could develop and manage HR practices with affective commitment and talent engagement in reducing turnover intentions
Comparative Study in Pyroshock Measurement using Noncontact Remote Laser and Bolted Accelerometers
No full textFPGA-based Implementation of Ultrasonic Energy Mapping for Non-destructive Evaluation Applications
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Screw-based modeling of soft manipulators with tendon and fluidic actuation
No full textA screw-based formulation of the kinematics, differential kinematics, and statics of soft manipulators is presented, which introduces the soft robotics counterpart to the fundamental geometric theory of robotics developed since Brockett's original work on the subject. As far as the actuation is concerned, the embedded tendon and fluidic actuation are modeled within the same screw-based framework, and the screw-system to which they belong is shown. Furthermore, the active and passive motion subspaces are clearly differentiated, and guidelines for the manipulable and force-closure conditions are developed. Finally, the model is validated through experiments using the soft manipulator for minimally invasive surgery STIFF-FLOP
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
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