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lumped-mass-model
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Dynamics of the nanoneedle probe in trolling mode AFM
, Article Nanotechnology ; Volume 26, Issue 20 , April , 2015 ; 09574484 (ISSN) ; Pishkenari, H. N ; Keramati, R ; Minary Jolandan, M ; Sharif University of Technology
Institute of Physics Publishing
2015
Abstract
Atomic force microscopy (AFM), as an indispensable tool for nanoscale characterization, presents major drawbacks for operation in a liquid environment arising from the large hydrodynamic drag on the vibrating cantilever. The newly introduced 'Trolling mode' (TR-mode) AFM resolves this complication by using a specialized nanoneedle cantilever that keeps the cantilever outside of the liquid. Herein, a mechanical model with a lumped mass was developed to capture the dynamics of such a cantilever with a nanoneedle tip. This new developed model was applied to investigate the effects of the needle-liquid interface on the performance of the AFM, including the imaging capability in liquid
Pipe dampers as passive devices for seismic control of isolated bridges
, Article Structural Control and Health Monitoring ; Volume 24, Issue 2 , 2017 ; 15452255 (ISSN) ; Maleki, S ; Sharif University of Technology
John Wiley and Sons Ltd
2017
Abstract
During an earthquake, pounding of bridge superstructure into abutments is potentially destructive to structural elements and may cause unseating failure and collapse. By using energy dissipative devices such as passive dampers, the harmful pounding force may be prevented. One of the most economical passive dampers for structural applications is the pipe damper, recently introduced by the authors. In this paper, computer models of a two-span 60-m long conventional overpass bridge are equipped with different lengths of two types of pipe dampers, namely the dual-pipe (DPD) and infilled-pipe (IPD) dampers. A simplified lumped-mass model for the bridge considering soil stiffness is proposed and...