Development of Ultrasonic Devices for Non-destructive Testing: Ultrasonic Vibro-tactile Sensor and FPGA-Based Research Platform

This thesis is focused on the development of ultrasonic devices for industrial non-destructive testing (NDT). Ultrasound is generated from mechanical vibrations and then propagates through the medium. Ultrasonic devices can make use of the ultrasound in both aspects, vibrations and propagations, to perform inspections of the objects. To this end, two devices were developed in this research, each pertaining to NDT of the objects. The first device is the vibro-tactile sensor which aims to estimate the elastic modules of soft materials with minimally invasive technique. Inspired by load sensitivity studies in the high-power ultrasonic applications, vibration characteristics in resonance were utilized to perform the inspection. Only a minimal force to ensure contact with the object surface needs to be applied for a vibro-tactile sensor to perform inspection of the object; hence, it can be used for in-vivo measurement of the soft materials’ elastic moduli without causing severe surface deformation. The design and analysis of the device were carried out using the electro-mechanical analogy to address the electro-mechanical nature of piezoelectric devices. The designed vibro-tactile sensor resonates at ~40 kHz and can be applied to differentiate the elastic modulus of isotropic soft samples with a range from 10 kPa to 70 kPa. The second device developed is a field-programmable development platform for ultrasonic pulse-echo testing. Ultrasonic testing, utilizing sound wave propagation, is a widely used technique in the industry. The commercially available equipment for industrial NDT is highly dependent on the competence of the inspector and rarely provides the access to raw data. For successful transition from traditional labor-intensive manufacturing to the next generation “smart factory” where intelligent machines replace human labor, inspection equipment with automated in-line data collection and processing capability is highly needed. To this end, a flexible platform which provides the access to raw data for algorithm development and implementation should be established. Therefore, an affordable, versatile, and researcher-friendly development platform based on field-programmable gate array (FPGA) was developed in the research. Both hardware and software development tools and procedures were discussed. In the lab experiment, the developed prototype exhibited its competence in NDT applications and successfully carried out hardware-based auto-detection algorithm for mm-level defects on steel and aluminum specimens. Comparisons with commercial systems were provided to guide future development

Collective analog bioelectronic computation

Thesis (Ph. D.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2009.This electronic version was submitted by the student author. The certified thesis is available in the Institute Archives and Special Collections.Cataloged from student submitted PDF version of thesis.Includes bibliographical references (p. 677-710).In this thesis, I present two examples of fast-and-highly-parallel analog computation inspired by architectures in biology. The first example, an RF cochlea, maps the partial differential equations that describe fluid-membrane-hair-cell wave propagation in the biological cochlea to an equivalent inductor-capacitor-transistor integrated circuit. It allows ultra-broadband spectrum analysis of RF signals to be performed in a rapid low-power fashion, thus enabling applications for universal or software radio. The second example exploits detailed similarities between the equations that describe chemical-reaction dynamics and the equations that describe subthreshold current flow in transistors to create fast-and-highly-parallel integrated-circuit models of protein-protein and gene-protein networks inside a cell. Due to a natural mapping between the Poisson statistics of molecular flows in a chemical reaction and Poisson statistics of electronic current flow in a transistor, stochastic effects are automatically incorporated into the circuit architecture, allowing highly computationally intensive stochastic simulations of large-scale biochemical reaction networks to be performed rapidly. I show that the exponentially tapered transmission-line architecture of the mammalian cochlea performs constant-fractional-bandwidth spectrum analysis with O(N) expenditure of both analysis time and hardware, where N is the number of analyzed frequency bins. This is the best known performance of any spectrum-analysis architecture, including the constant-resolution Fast Fourier Transform (FFT), which scales as O(N logN), or a constant-fractional-bandwidth filterbank, which scales as O (N2).(cont.) The RF cochlea uses this bio-inspired architecture to perform real-time, on-chip spectrum analysis at radio frequencies. I demonstrate two cochlea chips, implemented in standard 0.13m CMOS technology, that decompose the RF spectrum from 600MHz to 8GHz into 50 log-spaced channels, consume < 300mW of power, and possess 70dB of dynamic range. The real-time spectrum analysis capabilities of my chips make them uniquely suitable for ultra-broadband universal or software radio receivers of the future. I show that the protein-protein and gene-protein chips that I have built are particularly suitable for simulation, parameter discovery and sensitivity analysis of interaction networks in cell biology, such as signaling, metabolic, and gene regulation pathways. Importantly, the chips carry out massively parallel computations, resulting in simulation times that are independent of model complexity, i.e., O(1). They also automatically model stochastic effects, which are of importance in many biological systems, but are numerically stiff and simulate slowly on digital computers. Currently, non-fundamental data-acquisition limitations show that my proof-of-concept chips simulate small-scale biochemical reaction networks at least 100 times faster than modern desktop machines. It should be possible to get 103 to 106 simulation speedups of genome-scale and organ-scale intracellular and extracellular biochemical reaction networks with improved versions of my chips. Such chips could be important both as analysis tools in systems biology and design tools in synthetic biology.by Soumyajit Mandal.Ph.D

Proceedings of the 19th Sound and Music Computing Conference

Proceedings of the 19th Sound and Music Computing Conference - June 5-12, 2022 - Saint-Étienne (France). https://smc22.grame.f