Abstract:We evaluated the dynamic micromixing performances in slanted groove micromixers (SGM) and staggered herringbone micromixers (SHM) and quantitatively compared their differences using concentration vs. channel length profiles obtained from numerical stimulations. It is found that faster and finer mixing took place in the SHM and the chaotic mixing was more effective at locations closer to the grooves; in comparison, slower and coarser mixing occurred throughout the whole channel of the SGM. Subsequently, the concentration profile-based characterization method was demonstrated in hybrid floor-grooved micromixers to study the interaction of SGM and SHM.

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In this paper, the dynamic characteristics and vibration control of a rotating cantilever plate with fully covered active constrained layer damping (ACLD) treatments are investigated. The cantilever plate is rotating at different constant angular velocities about its normal to the horizontal plane. The model is based on the Kirchhoff classical laminated theory. The second kind of Lagrange formulation in conjunction with the finite element method (FEM) is developed to derive the governing equations of motion. Then the effects of different rotating angular velocities on modal characteristics of regular, passive constrained layer damping (PCLD) and ACLD treated-plate systems are investigated. In particular, frequency loci veering and crossing phenomena are exhibited and discussed in this work. Furthermore, the numerical simulation results of transient responses of regular, piezo-treated, PCLD and ACLD treated non-rotating and rotating plates in time domain are presented, respectively. Comparison of the performance of piezo, PCLD and ACLD treatments clearly demonstrate the merits of using ACLD as an effective means for suppressing the vibration of rotating cantilever plates. The results of this work are useful for system identification and vibration suppression of rotating flexible structures.

Anonymous credentials are a solid foundation for privacy-preserving Single Sign-On (SSO). They enable unlinkable authentication across domains and allow users to prove their identity without revealing more than necessary. Unfortunately, anonymous credentials schemes remain difficult to use and complex to deploy. They require installation and use of complex software at the user side, suffer from poor performance, and do not support security features that are now common, such as two-factor authentication, secret recovery, or support for multiple devices. In contrast, Open ID Connect (OIDC), the de facto standard for SSO is widely deployed and used despite its lack of concern for users’ privacy. We present EL PASSO, a privacy-preserving SSO system based on anonymous credentials that does not trade security for usability, and can be incrementally deployed at scale alongside Open ID Connect with no significant changes to end-user operations. EL PASSO client-side operations leverage a WebAssembly module that can be downloaded on the fly and cached by users’ browsers, requiring no prior software installation or specific hardware. We develop automated procedures for managing cryptographic material, supporting multi-device support, secret recovery, and privacy-preserving two-factor authentication using only the built-in features of common Web browsers. Our implementation using PS Signatures achieves 39x to 180x lower computational cost than previous anonymous credentials schemes, similar or lower sign-on latency than Open ID Connect and is amenable for use on mobile devices.

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