Thomas B. Jones

Professor of Electrical Engineering

Ph.D., Massachusetts Institute of Technology, 1970

Other Research Interests

Key Words:

microfluidics & microTAS, the "laboratory on a chip", dielectrophoresis and electrowetting, electromechanics of liquids and particles, industrial electrostatics, JAVA-based interactive nomograms, electric & magnetic levitation, Levitron

Electromechanics of Particles

The goal of our research in particle electromechanics at the University of Rochester is to understand the nature of electrical and magnetic interactions among particles in the 5 to 500 micrometer size range and to improve prediction of the electromechanics of systems of such particles. Practical implications of this work extend from xerographic copy machines and granular beds to novel miniaturized electrode structures for the manipulation of cells and other bioparticles. Over the years, this activity has received support from NSF and NATO, plus several New York State industrial R&D laboratories. Major research areas are listed below.

Biological Dielectrophoresis

The application of variable-frequency, non-uniform, electric fields to collect, align, probe, and process biological cells, DNA, and other bio-particles is becoming an important methodology in bio- technology. The recent move toward using microstructures to synthesize unique electric field configurations suitable for manipulating individual cells has created a need to predict more accurately the electromechanical forces and torques that make possible the new technology. Our laboratory was first to use feedback-controlled dielectrophoretic levitation to measure the membrane capacitance of individual cells and the dipole moments of particle chains.

In collaboration with Prof. M. Washizu of Tokyo University (Japan), we developed very general methods for predicting DEP forces and torques in microelectrode structures.

Another collaboration with Dr. N. Green (Southampton U.) and Prof. S. McAleavey (U of R) involved using numerical techniques to calculate the effective dipole moments of irregular particles for which standard analytical solutions are not amenable. From these effective moments, forces and torques can be estimated.

Papers on particle DEP & Levitation:

Books:

• Electromechanics of Particles, Cambridge University Press, New York City, NY, 1995.

Electrostatics

Our work in the broad area of electrostatics maintains a practical focus on consulting and training in the area of industrial electrostatic hazards and nuisances of charged powders and liquids. From 1991 to 2003, Prof. Jones served as Editor-in-Chief of the Journal of Electrostatics.

Electrostatic Hazards in Powders and Liquids

Dust and vapor explosions ignited by electrostatic discharges are a serious problem in the petroleum, pharmaceuticals, and plastics industries. Even now, the nature of charge relaxation processes and their influence upon explosion hazards are not well-understood. past research in this area has encompassed experimental and theoretical investigations. One project focussed on high-voltage dielectric test techniques for inspecting the glass anti-corrosion linings on chemical reaction vessels.

Industrial Electrostatics Demonstrations

A web site devoted to electrostatics demonstrations is maintained that covers important electrostatic phenomena relevant to manufacturing and commercial operations. These demonstrations have the practical aim of providing operators and manufacturing engineers an understanding of how electrostatic phenomena can cause product quality problems as well as serious accidents in the polymer, pharmaceutical, film manufacturing, and petrochemical industries. More than 50 lecture demonstrations have been presented around the world to audiences ranging from students to practicing engineers and researchers to operating personnel and safety officers. To arrange a lecture/demonstration, please inquire by email.

Books and Book Chapters:

On-line Interactive Nomograms

Nowadays, JAVA applets implemented on the Web place very user-friendly yet powerful analysis tools into the hands of more and more people in more and more work settings. One such scheme is interactive nomograms, which are graphic calculational tools that use the computer screen and a mouse as the interface. CLICK HERE for a practical example of an on-line nomogram used for assessing electrostatic ignition risks in flammable atmospheres of gas, vapor, or powder.

Long before the advent of handheld calculators, nomograms, which are closely related to the old-fashioned slide rule, were used extensively by engineers to facilitate tedious design calculations. Even today, they are still useful in situations where it is important to be able to refer to typical values for the important parameters in practical units for specific technical disciplines. Nomograms are commonplace in diagnostic medicine and veterinary science. CLICK HERE to examine and test an on-line nomogram generation tool.

The on-line nomogram project was made possible by grants from the Faculty Instructional Technology Initiative Program of the College Teaching Learning and Technology Roundtable (two grants) and the Wadsworth C. Sykes Engineering Endowment administered by the School of Engineering and Applied Science, both of the University of Rochester