107 research outputs found
Role of the electro-thermo-mechanical multiple coupling on the operation of RF microswitch
A phenomenological approach is proposed to identify some effects occurring within the structure of the microswitch conceived for radio frequency application. This microsystem is operated via a nonlinear electromechanical action imposed by the applied voltage. Unfortunately, it can be affected by residual stress, due to the microfabrication process, therefore axial and flexural behaviors are strongly coupled. This coupling increases the actuation voltage required to achieve the so-called ‘‘pull-in'' condition. Moreover, temperature may strongly affect strain and stress distributions, respectively. Environmental temperature, internal dissipation of material, thermo-elastic and Joule effects play different roles on the microswitch flexural isplacement. Sometimes buckling phenomenon evenly occurs. Literature show that all those issues make difficult an effective computation of ‘‘pull-in'' and ‘‘pull-out'' voltages for evenly distinguishing the origin of some failures detected in operation. Analysis, numerical methods and experiments are applied to an industrial test case to investigate step by step the RF-microswitch operation. Multiple electro-hermomechanical coupling is first modeled to have a preliminary and comprehensive description of the microswitch behavior and of its reliability. ‘‘Pull-in'' and ‘‘pull-out'' tests are then performed to validate the proposed models and to find suitable criteria to design the RF-MEM
JPN Guidelines for the management of acute pancreatitis: treatment of gallstone-induced acute pancreatitis
Gallstones, along with alcohol, are one of the primary etiological factors of acute pancreatitis, and knowledge of the etiology as well as the diagnosis and management of gallstones, is crucial for managing acute pancreatitis. Because of this, evidence regarding the management of gallstone-induced pancreatitis in Japan was collected, and recommendation levels were established by comparing current clinical practices with optimal clinical practices. The JPN Guidelines for managing gallstone-induced acute pancreatitis recommend two procedures: (1) an urgent endoscopic procedure should be performed in patients in whom biliary duct obstruction is suspected and in patients complicated by cholangitis (Recommendation A); and (2) after the attack of gallstone pancreatitis has subsided, a laparoscopic cholecystectomy should be performed during the same hospital stay (Recommendation B)
Experimental characterization of electrostatically actuated in-plane bending of microcantilevers
Experimental validation of numerical models developed by the authors to predict the static behaviour of microelectrostatic actuators is described. Cantilever microbeams, currently used in connection with RF-MEMS and micro-scale material testing were analysed. A set of microcantilevers, bending in the plane of the wafer, i.e. in the same plane as the profiling system's target, was tested. This differs from the popular case of out-of-plane microbeams, usually studied in the literature. Geometry nonlinearity caused by large deflection of the microbeam was investigated and nonlinear coupled formulation of electromechanical equilibrium was performed. Coupled-field analysis was implemented using the Finite Element Method (FEM), to predict displacements and pull-in voltage measured by Fogale Zoomsurf 3D, subsequently plotting the displacement-versus-voltage curve to complete model validation. FEM nonlinear analysis, based on iterative approach with mesh morphing, and FEM non-incremental approach, including a special element proposed by the authors, are compared to the linear solution and to experimental results. Geometry nonlinearity appears relevant in microbeam modelling and requires a nonlinear solution of the coupled problem. Investigative work, which compared the results of 2D and 3D models to experimental data, revealed that some three dimensional effects are significant in model validation, but the 2D approach may be effective in predicting static behaviour provided that at least a microbeam thickness equivalent is adopte
Humanoid robot adoption and labour productivity: a perspective on ambidextrous product innovation routines
The increasing presence of humanoid robot adoption has generated a change in explorative and exploitative routines. If the explorative routines provoke creativity and critical thinking which are delivered by humans, exploitative routines induce repetitive actions and mimic activities which are executed by humanoids. This has raised the need for a better balance between both routines involving an ambidextrous dynamic process. Here, product innovations play a relevant role in enhancing such balance and labour productivity. If, from the conceptual standpoint, this phenomenon has already been explored, there is still the need to empirically analyse it. We thus offer a meso-analysis of twenty-four countries located in Europe through the lens of the Service Robot Deployment (SRD) Model and the conceptual lens of organizational ambidexterity. By a regression methodology, the results show that humanoid robot adoption is still not affecting labour productivity which, by contrast, is positively and significantly connected with both radically new and marginally modified/unchanged production of innovative routines. Our original contribution, which falls in the field of Human Resources Management and Artificial Intelligence, is that humanoids are not directly impacting labour productivity but indirectly through the generation of both new and marginally modified (or unchanged) routines. This situation persuades senior leaders to achieve a balance between exploitative and explorative product innovation routines. Supplemental data for this article is available online at https://doi.org/10.1080/09585192.2021.1897643
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