Expert Details

Expert in Teaching and tutoring of mathematics and physics;

Expert ID: 724283 California, USA

Request Expert

There are two kinds of emission testing that Expert has done: sound pressure and sound power. Using sound pressure, Expert has determined local dB and/or dBA levels as well as measures of psychoacoustic metrics, such as Zwicker loudness, sharpness, intelligibility, roughness, etc. By means of sound intensity and sound power measurement, Expert has obtained localization of sound emission from a structure, as well as the calculation of the total sound power (in watts) radiated by a structure. Making a sound power measurement according to ISO 532B, Expert demonstrated that a new product from his company had only 1/2 the sound power emission of a competitor's, and this information was duly exploited by the marketing people.

Expert has performed experiments to determine the minimum number of degrees of freedom required in finite elements of centrifuge substructures, and he often used modal degrees of freedom for frequency response analysis when the number of physical degrees of freedom became excessively large (typically near 1 million dof).

In his studies of centrifuge dynamics, Expert utilized both computational techniques (such as finite element analysis) and experimental
techniques (such as frequency response function measurement and spectral decomposition of a time signal). His analyses of the dynamics of
centrifuges has allowed Beckman Coulter Corporation to remain the world leader in ultracentrifuge development and marketing while Expert
worked there.

Expert has worked both alone and with other consultants to precisely compare the acoustical performance of his company's products with those of the competition and to help show the way to improvement. His work during 2005-2007 resulted in the design of an ultracentrifuge whose noise output was only 5% that of its predecessor instrument.

Expert has used finite element (Nastran) models to calculate the normal and complex modes of centrifuges, to predict the instability of precessional modes of a rotating structure, to predict the response of a rotating system to rotor imbalance, and to predict the transient response of a system to a transient excitation. Examples of his experimental work include the use of measured frequency response functions to validate finite element models, the use of accelerometers and displacement probes to measure the time-dependence of motions on the structure, and the use of impact hammers and shakers to excite structures in controlled ways.

For more than 15 years, Expert played the lead role at Beckman Coulter Corporation in both computational and experimental dynamics for centrifuge development, and he mentored the younger engineers there in the application of those techniques.

Expert measured vibrations using accelerometers, eddy-current proximity probes, and capacitative probes. Some of these measurements were of vibrations during operation of centrifuges, while others were responses to measured force excitations (from an impact hammer or an electromagnetic shaker). Both the accelerometers and the force transducers were of the piezoelectric variety, with some of them requiring charge amplifiers and others (ICP) being stand-alone. The vibration data were used to confirm finite element model accuracy (via frequency response functions), design improvements, and sources of acoustical noise. The data were used to improve product performance and to help manufacturing improve their yields.

Expert always used calibration shakers to insure that the sensitivity of his accelerometers was known to within better than 1% accuracy. He calibrated eddy-current proximity probes and capacitative probes by means of micrometer-driven displacement stages (e.g., from Newport Corporation). He calibrated force cells indirectly using a ballistic pendulum of known mass. He was responsible for the annual calibration of all the sound and vibration instrumentation at Beckman Coulter's Palo Alto site via the use of a professional facility (Odin Metrology, Inc.) using procedures and equipment traceable to NIST standards.

Expert used vibration testing, over a period of more than 15 years, for the following purposes:

1) Diagnosis of sub-sychronous whirl in centrifuge drives, using spectral analysis.

2) High amplitude vibration of panels leading to undesirable acoustic radiation.

3) Generation of frequency response functions for determining the frequencies of resonances.

4) Determination of non-linear vibrations via spectral analysis of raw data.

5) Comparison of design iterations with respect to their vibration performance.

Using Nastran code and modal testing, he played the key dynamics analysis role in the design of a new family of general purpose centrifuges. As Beckman Coulter's in-house consultant in the field of structural dynamics, he helped to make the Allegra-15 centrifuge the quietest general purpose centrifuge created by Beckman Coulter since 1985.Using Nastran, diagnosed and prescribed successful treatment for a vibration problem that led to a one month stop-ship condition following the adoption of a cost-control design change. Resolution of the problem resulted in resumption of shipping in less than 3 weeks.Using impact hammer testing, diagnosed a cooling fin resonance that was generating unacceptable noise in a new ultracentrifuge model. Worked with design engineer to modify fin design, resulting in satisfactory acoustical performance.Using non-synchronous perturbation testing, diagnosed a sub-synchronous unstable precessional mode that was creating problems in manufacturing of a general purpose centrifuge. The problem was eventually found to be due to loss of damping in an elastomeric mount owing to elevated temperature. Change of the elastomer solved the instability problem.Using patented techniques for centrifuge motor speed control, found an absolutely optimized speed protocol for the separation of nicked from circular DNA plasmids from bacteria.

Expert may consult nationally and internationally, and is also local to the following cities: San Jose, California - San Francisco, California - Sacramento, California - Oakland, California - Stockton, California - Fremont, California - Modesto, California - Salinas, California - Santa Rosa, California - Hayward, California

Request Expert


Year Degree Subject Institution
Year: 1984 Degree: Ph.D Subject: Physics Institution: University of Illinois (Urbana)
Year: 1979 Degree: M.S. Subject: Physics Institution: University of Illinois (Urbana)
Year: 1971 Degree: A.B. Subject: Biology & Physics Institution: University of California, Berkeley

Work History

Years Employer Title Department Responsibilities
Years: 1988 to 2008 Employer: Beckman Coulter, Inc. Title: Senior Staff Physicist Department: Engineering/Product Development Responsibilities: He is responsible for technical lead for solution of all structural dynamical and acoustical problems concerning centrifuge development and line engineering. Also responsible for mentoring of junior engineers in those fields and for importing needed technologies (e.g., finite elements) for solving those kinds of problems.
Years: 1990 to 1993 Employer: College of San Mateo Title: Instructor Department: Mathematics & Sciences Responsibilities: He was responsible for creating and teaching a course on conceptual physics, over a period of 4 years, for non-majors. Specifically, he chose the textbook, wrote and delivered all the lectures and lab demonstrations, assigned and graded all homework and examinations, and gave final grades to students.
Years: 1985 to 1987 Employer: Cornell University Title: Post-doctoral research associate Department: Applied & Engineering Physics Responsibilities: He designed and procurred all optics, electronics, and software for acquiring data concerning kinetics studies of neurotransmitter receptor channel opening.
Years: 2008 to Present Employer: Undisclosed Title: Private physics and math tutor Department: Responsibilities: He is for hire as a private tutor in physics and mathematics for college and high school students.

International Experience

Years Country / Region Summary
Years: 1980 to 1980 Country / Region: Hungary Summary: As part of a three-way collaboration between the Hungarian Academy of Science's Biological Research Center in Szeged, UC San Francisco's Cardiovascular Research Institute, and University of Illinois Department of Physics, Expert did research on light energy transduction in bacterial cell membranes in Szeged, Hungary, during the entire summer of 1980. He also attended an International Conference on Bacteriorhodopsin that was held there in September 1980.
Years: 1984 to 1985 Country / Region: Japan Summary: With a grant award from NSF's US-Japan Cooperative Science Program, Expert did research at Rikagaku Kenkyusho (RIKEN) on the dynamics and structure of bacteriorhodopsin. He published papers on the dynamics of the C-terminus of the protein (studied with fluorescence polarization anisotropy decay), crystallization of a mutant form of the protein (using dynamic light scattering), and also a paper on light-energy transduction research in Japan for the U.S. Office of Naval Research.

Career Accomplishments

Associations / Societies
American Physical Society;
Acoustical Society of America
Awards / Recognition
Awarded grant from National Science Foundation for work in Japan concerning the dynamics of a light-energy transducing protein (1984)

Awarded Founder's Award at Beckman Coulter, Inc., in 1997, for focus on global outlook.
Publications and Patents Summary
He has over 20 publications and 2 patents.

Additional Experience

Training / Seminars
For a period of three years, he organized a weekly seminar program for engineers and scientists at Beckman Instruments, Inc., during which time he delivered more than 25 seminars on subjects ranging from sedimentation theory to the theory of analytical ultracentrifugation (using absorption and interference optics).
Vendor Selection
In addition to many others purchases, he selected a vendor (McNeal Schwendler Corporation) for a finite element program (Nastran) a data acquisition system for rotating machinery from Bently Nevada Corporation, a complete sound and vibration data acquisition and analysis system from LMS International, a large set of accelerometers, load cells, and impact hammers from Bruel & Kjaer, data acquisition boards and signal conditioning boards from Keithley, Alligator Technologies, and National Semiconductor, an electrodynamic shaker from Ling Electronics, a viscometer from Brookfield, a calibrated sound source from G&G Acoustics, Inc., a high quality sound intensity probe from G.R.A.S. Electronics, Inc., and capacitative displacement probes from Capacitek, Inc.
Other Relevant Experience
He created training programs for engineers and technicians at Beckman Coulter, Inc. in the field of structural dynamics, include impact hammer testing, finite element analysis (using Nastran), and sound and vibration testing. He has extensive experience measuring psychoacoustic metrics for product development engineers.
Before coming to Beckman Instruments in 1988, he had experience with experimentation in protein biophysics, such as kinetic absorption spectroscopy, photochemistry with a fluorescence microscope, high pressure measurements, and time-resolved fluorescence spectroscopy.

Language Skills

Language Proficiency
French He is familiar with very basic French, having studied it in high school.
German Having grown up around parents from Germany, he can understand and speak some German.
Japanese He studied Japanese while he lived in Japan during 1984. He still considers himself a beginner in the language.

Fields of Expertise

Request Expert

Dev Tool:

Request: expert/teaching-and-tutoring-of-mathematics-and-physics
Matched Rewrite Rule: expert/([^/]+)(?:/([0-9]+))?/?$
Matched Rewrite Query: experts=teaching-and-tutoring-of-mathematics-and-physics&page=
Loaded Template: single-experts.php