Search results for "Structural dynamics"

Structural Dynamics and Intentional Governance in Strategic Interorganizational Network Evolution: A Multilevel Approach

2016

This article aims to shed light on the drivers underlying the role and scope of intentional governance of the structural dynamics of whole interorganizational networks. Prior research has distinguished networks that are emergent from networks that are orchestrated. While empirical studies have shown situations in which the role and scope of intentional governance of whole interorganizational networks has changed in time, and there is a growing interest regarding the endogenous drivers of network dynamics, the dimensions that influence intentional governance of network structure dynamics and the way this is carried out remain still to be elucidated. In order to pinpoint these drivers, we le…

Visualizing a protein quake with time-resolved X-ray scattering at a free-electron laser

2014

We describe a method to measure ultrafast protein structural changes using time-resolved wide-angle X-ray scattering at an X-ray free-electron laser. We demonstrated this approach using multiphoton excitation of the Blastochloris viridis photosynthetic reaction center, observing an ultrafast global conformational change that arises within picoseconds and precedes the propagation of heat through the protein. This provides direct structural evidence for a 'protein quake': the hypothesis that proteins rapidly dissipate energy through quake-like structural motions. peerReviewed

Determination of the oxygen transmissibility and permeability of hydrogel contact lenses

1999

To test the validity of the method of stacked hydrogel contact lenses to obtain the oxygen permeability and transmissibility coefficients of the lenses, the coefficients of one low hydration (38% water) and two high hydration (55 and 58% water) hydrogel contact lenses stacked one to five on an oxygen electrode were deter- mined. From the oxygen diffusion through the lenses, the current intensity in the stationary state was determined, and from this the "instrument" the oxygen transmis- sibility was obtained. The permeability coefficients of the lenses, corrected for edge effects, were obtained from the slope of the plot of the reciprocal of the transmissibility coefficients versus the lens …

Proceedings of MDP2007 international Symposium on Recent Advances in Mechanics (structural/solid) Dynamical Systems (deterministic/stochastic) Probab…

2009

Influence of the effectiveness factors in assessing the shear capacity of RC beams strengthened with FRP

2021

Shear failure of RC beams strengthened with composite textiles is often affected by the different failure modes characterizing the FRP reinforcement. The most relevant analytical models for evaluating the shear capacity of RC beams strengthened with FRP take into account these failure modes by introducing an effectiveness factor “R”, which reduces the ultimate FRP tensile stress. Moreover, the interaction between stirrups and FRP reinforcement leads to a reduced efficiency of the transverse steel reinforcement due to the brittle failure of composite textile which hinders the yielding of all the stirrups involved by critical crack. In this regard, some analytical models introduce an effectiv…

Variable Friction Dampers (VFD) for a modulated mitigation of the seismic response of framed structures: Characteristics and design criteria

2022

In this paper a new approach for the energy dissipation is discussed based on the use of Variable Friction Dampers (VFDs). The VFD device is borrowed from braking systems mechanical engineering, able to modulate its capability of dissipation, providing a constant pure friction force coupled with an additional (variable) damping force with the increasing of the displacement. Resorting to a previous study, the characteristics and the efficiency of the “braking” system in terms of reduction of the displacements and the restoring forces is described for SDOF systems under seismic excitations and compared with the performances achievable by classic constant friction dampers (CFDs). Then, a desig…

Structural Dynamics of Interfirm Knowledge Networks

2016

In this chapter, we investigate the drivers of interfirm network structural dynamics and their influence on knowledge creation and diffusion processes that occur in such networks over time. Interfirm knowledge networks are complex webs of linkages connecting a variety of idiosyncratic firms within and across industries. Aimed to contribute to answer the recent calls for a more dynamic and multilevel view to understand network structures and processes, we leverage the complex network research to formulate a multilevel theoretical framework that clarifies the structural dynamics and knowledge creation and diffusion potential of interfirm networks.