Albert P. Pisano’s research while affiliated with University of California, Berkeley and other places

The full nonlinear equations of motion are derived for a general angularly driven rate gyro. Sensitivity to cross-axis angular input rates and angular input accelerations are shown in simplified form for design purposes. The gyro drive and sense axes can be operated either nonresonantly or resonantly where the natural frequencies coincide with the forcing moment. The tuning requirements and increase in coriolis sensitivity for resonant operation are detailed. Using this tuning technique, a two input axis micromachined rate gyro has been fabricated which can sense 0.15 °/sec in a 20Hz bandwidth.

At the close of their June 2021 summit in Cornwall, the heads of state of the G7 nations issued a blueprint for developing potentially pivotal sovereign-to-sovereign science and technology (S&T) agreements for robust collective action in research and development (R&D): the G7 Research Compact (1). If such agreements can be properly focused and executed—and broadened over time to include other democracies—it could unlock solutions to a class of pressing global problems that can only be effectively addressed by multilateral, public-private applied R&D collaboration. Yet, an uneven track record of such collaboration thus far suggests that the G7 must modernize their international S&T agreements to generate more dexterity in establishing and managing cross-border R&D relationships, especially to enhance their economic growth and global competitiveness. To do this, the G7 must redesign their approach so that R&D collaboration is integrated into their international trade and investment agreements.

Rules for S&T collaboration should be integrated with trade and investment agreements.

This article proposes a novel control algorithm of a thermal phase-change process and shows its experimental verification using paraffin as a phase-change material (PCM). The core problem is to design a boundary feedback control for the "Stefan system" that describes the time evolution of the temperature profile in the liquid phase, which is associated with the time evolution of a position of liquid-solid phase interface, for the sake of stabilizing the interface position at a chosen set point. First, we design the continuous-time full-state feedback control law by means of the PDE backstepping method, which, in the absence of a demand for accelerated convergence, can also be arrived at by the energy-shaping method, and rigorously prove the stability of the closed-loop system under sufficiently small heat loss. Next, the control law is refined via observer-based output feedback under sampled-data measurements of the surface temperature and the phase interface position so that the control algorithm is practically implementable. Then, we conducted an experiment under a constant input to calibrate unknown parameters involved with the heat loss. Finally, the proposed model-based boundary feedback control algorithm is implemented in the experiment of melting paraffin. The experiment was successful: the convergence of the phase interface to the set point was achieved.

A concept for the development of spectrum-clean S1 Lamb wave resonator (LWR) utilizing an aluminum nitride (AlN) plate with damped edge reflectors is demonstrated. Numerical analysis is performed on the dispersive characteristics of the Lamb modes propagating in AlN plates, and the design parameters to enable zero group velocity (vg) for the S1 mode are identified. The simulation results based on finite element analysis verify that the use of the damped edge reflectors, instead of the conventional edge reflectors, can efficiently de-couple most of the Lamb waves such as the S0 mode by mode conversion upon edges, but not the S1 mode characterizing zero vg. Specifically, the measured frequency response of a 1.38-GHz AlN S1 LWR with damped edge reflectors yields a clean spectrum up to 6 GHz and excellent resonance passband performance.

This study reports the design of a novel Butterfly Lamb wave resonator (LWR) employing the S ₀ mode in the AlN plate, and for the first time, its ultrahigh parallel-resonance quality factor (Q _p ) of 4,021 is demonstrated, indicating an ultralow acoustic loss. Although the series resonance quality factor (Q _s ) is widely used for various loss comparisons, it is inconclusive since Q _s is always dominated by the routing resistance (Rs), which is normally huge without the thick metal rewiring. Instead, Q _p is a precise representation of the acoustic loss level for its independence of R _s and as it is closer to Q _max of the Bode Q-curve in the IDT-excited devices. A butterfly-shaped resonance cavity, theoretically predicted to reduce the anchor loss and suppress the transverse spurious mode, has been applied to the AlN LWR and experimentally shown to boost the Q _p by 2.3 times. In addition, a directly measured Bode-Q curve for the LWR is reported for the first time, showing superior Q profile for the Butterfly-LWR than the conventional-LWR and good agreement with the 3 dB- Q _p 's.

Low-cost manufacturing technology for a micro-sized structure is receiving a lot of attention as human society is getting mixed with sensors and electronics. A template printing technology which forms micro-patterns by letting ink dried within a solvent permeable template is an attractive alternative of traditional costly micro-fabrication. However, low printing speed and lack of scalability have been recognized as a major drawback of this method. Here, we propose a novel printing machine using an inflatable polymer template. It is expected that thin membrane improves the printing speed due to its high permeation speed; however, the theoretical prediction and experimental proof of this approach has not been studied. A 450-μm thick membrane is fabricated by the casting polydimethylsiloxane (PDMS) on a silicon master mold, fixed to a printer head, and inflated to contact with substrate uniformly. The permeation mechanism is investigated by using both of the numerical simulation and experiments and discovers that the diffusion in thin membrane obeys an analytical solution for Fick’s diffusion in steady state, while a conventional bulk template (10 mm) is in non-steady state. The printing system composed of pneumatic lines, a flash sintering unit, and a printer head holds the membrane is prototyped to ensure reproducibility of this novel method, five times faster printing speed compared to the ordinal method is confirmed.

Miniature non-contact voltage sensor has significant benefit for condition monitoring of power systems in terms of ease of installation and a minimum disturbance to an existing design. The electrostatic field sensor miniaturized by MEMS (Micro Electro Mechanical Systems)technology is a promising method to realize low cost and small sensors. However, the behavior of micro-sized mechanical shutter under an intense electric field and performance as a voltage sensor are barely studied. Here, we design the SOI (Silicon on Insulator)based shutter which has multiple vibration modes, evaluate the performance under an intense electric field (˜1.4 MV/m). The vibration spectrum obtained by sensor output shows a resonance frequency shift and a non-linearity of sensitivity. These results are explained by a numerical model which consider a vertical displacement of shutter due to the tensile force from an electric field. Finally, practical demonstrations are carried such as a calibration for linear response using multiple linear regression analysis of sensor outputs with various resonance mode and evaluation of sensor bandwidth with a synthesized sinusoidal and rapid change of an electric field for a quantitative comparison with past studies.