Greater Minneapolis-St. Paul Area
Senior Principal Engineer in the medical device industry poised with Strong Leadership Skills in Management, Electronics, Transducers, Sensors, Manufacturing, and knowledge-based lean development using robust Design of Experiments. Passionate, inquisitive, creative and decisive instincts emphasizing analytical, computational, and empirical methods in knowledge-based lean development with a Ph.D. from Penn State University focused in the multi-disciplinary field of Engineering Acoustics (Physics, Data Acquisition, Signal Processing)
Hearing aids are class II medical devices. After I visited the campus, met the people and saw the engineering playground, I became passionate about Starkey's transition to digital platforms and the ripe innovation landscape. For 10 years I directed the daily work of a nimble R&D team of seven cross-functional engineers, developing new technologies from principle to prototype leading to 20+ patents issued, 7 pending. We actively collaborated with Sales, Marketing, Product Development, Quality, Continuation Engineering, Test, Wireless, and Systems Engineering. I received Starkey's 2011 ‘Light Bulb’ award for the most innovative research. My current cross-functional role as Senior Principal has me reporting directly to the VP of Advanced Development and interacting with the same groups. I've given more than 30 technical presentations and publications, including invited talks for: • Agile, Lean, Product Development Savvy Meeting, Minneapolis (2014) • 5th European DOE User’s Meeting, Cambridge, UK (2014) • Characterization of Rayleigh Damping Parameters of post-cured, hybrid, methacrylic materials used in stereolithography systems, 16th ICSV, Krakow, PL (2009) • MEPTEC symposium on medical electronics technology integration. Tempe, AZ (2006) My approach to robust design is based on ACES methods: • Analytical: mathematical conception of principles using Matlab • Computational: virtual prototyping of (sub)systems with SolidWorks and FEA: virtual drop tests and fatigue using ADINA; electromagnetic radiation using ANSOFT Maxwell and HFSS • Empirical: data acquisition and DSP analysis using spectrum analyzers, laser vibrometers, force cells, MEMS motion sensors, and 3D prototype printing • Statistical analysis using Stat-Ease DOE and CETOL for tolerance analysis I've met regularly with patent attorneys, helping in the strategic planning and protection of Intellectual Property and in ideation processes. I loved mentoring 10 summer interns!
In the Microphone Development Group, I studied the acoustic impedance of the thin air gap between the membrane and backplate of studio condenser microphones. At the time, we wanted to understand what gave the Neumann U87 capsule its warm sound. Some believed it was the center post on the large membrane, and that certainly was part of it, but I was fortunate enough to have seen this $3,500 capsule completely disassembled under a microscope, including the unique pattern of holes and cavities in the backplate. Although the analytical portion of this study was based on the work of Hersh and Rogers (NASA, 1976), I focused on developing a computational approach using multi-physics FEA. I needed a robust finite element that could capture both the fluid-structure interactions of the membrane and the non-linear losses of air viscosity and thermal conductivity at the boundaries. Toward this end, I used the Ingard/Ising data (JASA, 1967) as a target, and chose a slightly-compressible Navier-Stokes fluid element in ADINA. Recall that acoustic pressure is six orders of magnitude below ambient pressure, thus a typical NS element could yield inaccurate acoustic results - especially with fine meshes. The air gap was only a few microns thick and it was delicate work keeping the upwinding parameters under control in the implicit solver, but we were able to reproduce the famous Ingard/Ising empirical results for non-linear fluid flow through an orifice shown in FIG 5 of the Hersh/Rogers report in the link below. The epiphany to me was this: the stretched membrane of a condenser microphone will have resonances that can be measured in-vacuo, and the typical values will be spot-on the textbook values throughout the audio range of frequencies. However, once the thin air gap is introduced, the resonances are increased beyond 20kHz. (Good) studio condenser mics operate below the lowest membrane / air-gap resonance and that's why their response is so flat.
This was my first gig out of graduate school. I had other offers, but I chose this firm because I wanted to be exposed to the prestigious spaces it had contracted globally. I am indebted to the senior consultants who mentored me. At first, I performed ancillary tasks on the bigger projects: reverberation time calculations for the movable ceiling of Dewan Filharmonik Petronas Hall in Kuala Lumpur, ray tracing in Chicago's Symphony Center, and some HVAC ambient noise calculations. In a short time, I was assigned as project manager collaborating with a team of clients and architects during programming, schematics, design development and contract documents for the $14M Paul Porter Performing Arts Center at Brevard College. The budget was tight, and they wanted to lower the height of the space to reduce cost. At the time, I was studying the difference in reverberation of Boston Symphony Hall and Avery Fisher (David Geffen) Hall in Lincoln Center. The two spaces are similar in plan and height, but Boston is much superior. Why? One reason is that the 3rd balcony of seats in Avery Fisher chokes the development of room modes. Boston only has two balconies, so I wanted Brevard to keep 10 feet of uninterrupted wall space above their balcony for room modes to develop and spill down on the audience. We kept the height and saved money by opting for a membrane roof, and although concerts may be noisier during thunderstorms, we felt it was a good tradeoff. I also collaborated with a Chicago law firm and architect in a $14M settlement with O'Hare airport for noise insulation in surrounding schools. The lawyer wanted me to establish the SNR needed for classroom learning. Every 5dB of SNR translated into $2.3M of noise insulation materials. We settled on 30dB SNR. I was assigned to the larger church projects: Trinity Church Wall Street, Queen of All Saints Basilica in Chicago, Church of Christ Scientist in Boston. Loved working on them.