Bio


Kenny's group is researching fundamental issues and applications of micromechanical structures. These devices are usually fabricated from silicon wafers using integrated circuit fabrication tools. Using these techniques, the group builds sensitive accelerometers, infrared detectors, and force-sensing cantilevers. This research has many applications, including integrated packaging, inertial navigation, fundamental force measurements, experiments on bio-molecules, device cooling, bio-analytical instruments, and small robots. Because this research field is multidisciplinary in nature, work in this group is characterized by strong collaborations with other departments, as well as with local industry.

Academic Appointments


Honors & Awards


  • General Chair, Transducers 2015 (2015)
  • Technical Achievement Award, IEEE (2011)
  • Program Manager, DARPA Microsystems Technology Office (2006-2010)
  • Captain, Ultimate Frisbee Coed World Champions (RFBF) (1999)
  • Captain, Ultimate Frisbee Coed National Champions (RFBF) (1998)
  • Terman Fellowship, Stanford University (1995-1998)
  • Robert Bosch Faculty Scholar, Robert Bosch Foundation (1995-1999)
  • CAREER Award, NSF (1995-1999)

Boards, Advisory Committees, Professional Organizations


  • Board of Directors, SiTime Corporation (2004 - Present)

Professional Education


  • PhD, UC Berkeley, Physics (1989)

Patents


  • Daniel J. Lenehan, Kenneth Goodson, Thomas W. Kenny, Mark Munch, Saroj Sahu. "United States Patent 8,602,292 Pump and Fan Control Concepts in a Cooling System", Cooligy, Inc, Dec 10, 2013
  • Thomas Kenny, Mark Munch, Peng Zhou, James Gill Shook, Kenneth Goodson, Dave Corbin, Mark McMaster, James Lovette. "United States Patent US 8,464,781 Cooling Systems Incorporating Heat Exchangers and Thermoelectric Layers", Cooligy, Inc, Jul 18, 2013
  • Robert J. Full, Ronald S. Fearing, Thomas W. Kenny, Kellar Autumn. "United States Patent US 6,737,160 Adhesive Microstructure and Method of Forming Same", The Regents Of The University Of California, May 18, 0004

2013-14 Courses


Journal Articles


  • Stability of Silicon Microelectromechanical Systems Resonant Thermometers IEEE SENSORS JOURNAL Ng, E. J., Lee, H. K., Ahn, C. H., Melamud, R., Kenny, T. W. 2013; 13 (3)
  • Topology Optimization of Stressed Capacitive RF MEMS Switches JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Philippine, M. A., Sigmund, O., Rebeiz, G. M., Kenny, T. W. 2013; 22 (1): 206-215
  • Bidirectionally tuning Kapitza conductance through the inclusion of substitutional impurities JOURNAL OF APPLIED PHYSICS Duda, J. C., English, T. S., Piekos, E. S., Beechem, T. E., Kenny, T. W., Hopkins, P. E. 2012; 112 (7)

    View details for DOI 10.1063/1.4757941

    View details for Web of Science ID 000310489400041

  • Phase and thickness dependent modulus of Ge2Sb2Te5 films down to 25 nm thickness APPLIED PHYSICS LETTERS Won, Y., Lee, J., Asheghi, M., Kenny, T. W., Goodson, K. E. 2012; 100 (16)

    View details for DOI 10.1063/1.3699227

    View details for Web of Science ID 000303128500018

  • Electrical and Thermal Conduction in Atomic Layer Deposition Nanobridges Down to 7 nm Thickness NANO LETTERS Yoneoka, S., Lee, J., Liger, M., Yama, G., Kodama, T., Gunji, M., Provine, J., Howe, R. T., Goodson, K. E., Kennyt, T. W. 2012; 12 (2): 683-686

    Abstract

    While the literature is rich with data for the electrical behavior of nanotransistors based on semiconductor nanowires and carbon nanotubes, few data are available for ultrascaled metal interconnects that will be demanded by these devices. Atomic layer deposition (ALD), which uses a sequence of self-limiting surface reactions to achieve high-quality nanolayers, provides an unique opportunity to study the limits of electrical and thermal conduction in metal interconnects. This work measures and interprets the electrical and thermal conductivities of free-standing platinum films of thickness 7.3, 9.8, and 12.1 nm in the temperature range from 50 to 320 K. Conductivity data for the 7.3 nm bridge are reduced by 77.8% (electrical) and 66.3% (thermal) compared to bulk values due to electron scattering at material and grain boundaries. The measurement results indicate that the contribution of phonon conduction is significant in the total thermal conductivity of the ALD films.

    View details for DOI 10.1021/nl203548w

    View details for Web of Science ID 000299967800026

    View details for PubMedID 22224582

  • Mechanical characterization of aligned multi-walled carbon nanotube films using microfabricated resonators CARBON Won, Y., Gao, Y., Panzer, M. A., Dogbe, S., Pan, L., Kenny, T. W., Goodson, K. E. 2012; 50 (2): 347-355
  • Electrostatic Tuning to Achieve Higher Stability Microelectromechanical Composite Resonators JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Lee, H. K., Melamud, R., Kim, B., Hopcroft, M. A., Salvia, J. C., Kenny, T. W. 2011; 20 (6): 1355-1365
  • Stable Operation of MEMS Oscillators Far Above the Critical Vibration Amplitude in the Nonlinear Regime JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Lee, H. K., Melamud, R., Chandorkar, S., Salvia, J., Yoneoka, S., Kenny, T. W. 2011; 20 (6): 1228-1230
  • Influence of the temperature dependent nonlinearities on the performance of micromechanical resonators APPLIED PHYSICS LETTERS Lee, H. K., Kim, B., Melamud, R., Hopcroft, M. A., Salvia, J. C., Kenny, T. W. 2011; 99 (19)

    View details for DOI 10.1063/1.3660235

    View details for Web of Science ID 000297030200082

  • Orientation angle and the adhesion of single gecko setae JOURNAL OF THE ROYAL SOCIETY INTERFACE Hill, G. C., Soto, D. R., Peattie, A. M., Full, R. J., Kenny, T. W. 2011; 8 (60): 926-933

    Abstract

    We investigated the effects of orientation angle on the adhesion of single gecko setae using dual-axis microelectromechanical systems force sensors to simultaneously detect normal and shear force components. Adhesion was highly sensitive to the pitch angle between the substrate and the seta's stalk. Maximum lateral adhesive force was observed with the stalk parallel to the substrate, and adhesion decreased smoothly with increasing pitch. The roll orientation angle only needed to be roughly correct with the spatular tuft of the seta oriented grossly towards the substrate for high adhesion. Also, detailed measurements were made to control for the effect of normal preload forces. Higher normal preload forces caused modest enhancement of the observed lateral adhesive force, provided that adequate contact was made between the seta and the substrate. These results should be useful in the design and manufacture of gecko-inspired synthetic adhesives with anisotropic properties, an area of substantial recent research efforts.

    View details for DOI 10.1098/rsif.2010.0720

    View details for Web of Science ID 000290898500002

    View details for PubMedID 21288955

  • AC Polarization for Charge-Drift Elimination in Resonant Electrostatic MEMS and Oscillators JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Bahl, G., Salvia, J. C., Melamud, R., Kim, B., Howe, R. T., Kenny, T. W. 2011; 20 (2): 355-364
  • Wafer-Level Epitaxial Silicon Packaging for Out-of-Plane RF MEMS Resonators with Integrated Actuation Electrodes IEEE TRANSACTIONS ON COMPONENTS PACKAGING AND MANUFACTURING TECHNOLOGY Chen, K., Wang, S., Salvia, J. C., Melamud, R., Howe, R. T., Kenny, T. W. 2011; 1 (3): 310-317
  • 3-D visualization of flow in microscale jet impingement systems INTERNATIONAL JOURNAL OF THERMAL SCIENCES Won, Y., Wang, E. N., Goodson, K. E., Kenny, T. W. 2011; 50 (3): 325-331
  • Active Electrostatic Compensation of Micromechanical Resonators Under Random Vibrations JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Yoneoka, S., Salvia, J. C., Bahl, G., Melamud, R., Chandorkar, S. A., Kenny, T. W. 2010; 19 (5): 1270-1272
  • Effect of fibril shape on adhesive properties APPLIED PHYSICS LETTERS Soto, D., Hill, G., Parness, A., Esparza, N., Cutkosky, M., Kenny, T. 2010; 97 (5)

    View details for DOI 10.1063/1.3464553

    View details for Web of Science ID 000281059500064

  • Characterization of Encapsulated Micromechanical Resonators Sealed and Coated With Polycrystalline SiC JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Yoneoka, S., Roper, C. S., Candler, R. N., Chandorkar, S. A., Graham, A. B., Provine, J., Maboudian, R., Howe, R. T., Kenny, T. W. 2010; 19 (2): 357-366
  • What is the Young's Modulus of Silicon? JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Hopcroft, M. A., Nix, W. D., Kenny, T. W. 2010; 19 (2): 229-238
  • A Method for Wafer-Scale Encapsulation of Large Lateral Deflection MEMS Devices JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Graham, A. B., Messana, M. W., Hartwell, P. G., Provine, J., Yoneoka, S., Melamud, R., Kim, B., Howe, R. T., Kenny, T. W. 2010; 19 (1): 28-37
  • Real-Time Temperature Compensation of MEMS Oscillators Using an Integrated Micro-Oven and a Phase-Locked Loop JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Salvia, J. C., Melamud, R., Chandorkar, S. A., Lord, S. F., Kenny, T. W. 2010; 19 (1): 192-201
  • Model and Observations of Dielectric Charge in Thermally Oxidized Silicon Resonators JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Bahl, G., Melamud, R., Kim, B., Chandorkar, S. A., Salvia, J. C., Hopcroft, M. A., Elata, D., Hennessy, R. G., Candler, R. N., Howe, R. T., Kenny, T. W. 2010; 19 (1): 162-174
  • Development of wafer scale encapsulation process for large displacement piezoresistive MEMS devices SENSORS AND ACTUATORS A-PHYSICAL Ayanoor-Vitikkate, V., Chen, K., Park, W., Kenny, T. W. 2009; 156 (2): 275-283
  • Temperature-Insensitive Composite Micromechanical Resonators JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Melamud, R., Chandorkar, S. A., Kim, B., Lee, H. K., Salvia, J. C., Bahl, G., Hopcroft, M. A., Kenny, T. W. 2009; 18 (6): 1409-1419
  • Performance Evaluation and Equivalent Model of Silicon Interconnects for Fully-Encapsulated RF MEMS Devices IEEE TRANSACTIONS ON ADVANCED PACKAGING Chen, K., Salvia, J., Potter, R., Howe, R. T., Kenny, T. W. 2009; 32 (2): 402-409
  • Multimode thermoelastic dissipation JOURNAL OF APPLIED PHYSICS Chandorkar, S. A., Candler, R. N., Duwel, A., Melamud, R., Agarwal, M., Goodson, K. E., Kenny, T. W. 2009; 105 (4)

    View details for DOI 10.1063/1.3072682

    View details for Web of Science ID 000263803300018

  • Hermeticity and diffusion investigation in polysilicon film encapsulation for microelectromechanical systems JOURNAL OF APPLIED PHYSICS Kim, B., Candler, R. N., Melamud, R., Hopcroft, M. A., Yoneoka, S., Lee, H. K., Agarwal, M., Chandorkar, S. A., Yama, G., Kenny, T. W. 2009; 105 (1)

    View details for DOI 10.1063/1.3054366

    View details for Web of Science ID 000262534100047

  • Acceleration insensitive encapsulated silicon microresonator APPLIED PHYSICS LETTERS Jha, C. M., Salvia, J., Chandorkar, S. A., Melamud, R., Kuhl, E., Kenny, T. W. 2008; 93 (23)

    View details for DOI 10.1063/1.3036536

    View details for Web of Science ID 000261699700087

  • Temperature dependence of quality factor in MEMS resonators JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Kim, B., Hopcroft, M. A., Candler, R. N., Jha, C. M., Agarwal, M., Melamud, R., Chandorkar, S. A., Yama, G., Kenny, T. W. 2008; 17 (3): 755-766
  • Mission results for Sapphire, a student-built satellite ACTA ASTRONAUTICA Swartwout, M., Kitts, C., Twiggs, R., Kenny, T., Smith, B. R., Lu, R., Stattenfield, K., Pranajaya, F. 2008; 62 (8-9): 521-538
  • A study of electrostatic force nonlinearities in resonant microstructures APPLIED PHYSICS LETTERS Agarwal, M., Chandorkar, S. A., Mehta, H., Candler, R. N., Kim, B., Hopcroft, M. A., Melamud, R., Jha, C. M., Bahl, G., Yama, G., Kenny, T. W., Murmann, B. 2008; 92 (10)

    View details for DOI 10.1063/1.2834707

    View details for Web of Science ID 000253989300168

  • Thermal isolation of encapsulated MEMS resonators JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Jha, C. M., Hopcroft, M. A., Chandorkar, S. A., Salvia, J. C., Agarwal, M., Candler, R. N., Melamud, R., Kim, B., Kenny, T. W. 2008; 17 (1): 175-184
  • Ultraminiature encapsulated accelerometers as a fully implantable sensor for implantable hearing aids BIOMEDICAL MICRODEVICES Park, W., O'Connor, K. N., Chen, K., Mallon, J. R., Maetani, T., Dalal, P., Candler, R. N., Ayanoor-Vitikkate, V., Roberson, J. B., Puria, S., Kenny, T. W. 2007; 9 (6): 939-949

    Abstract

    Experiments were conducted to evaluate a silicon accelerometer as an implantable sound sensor for implantable hearing aids. The main motivation of this study is to find an alternative sound sensor that is implantable inside the body, yet does not suffer from the signal attenuation from the body. The merit of the accelerometer sensor as a sound sensor will be that it will utilize the natural mechanical conduction in the middle ear as a source of the vibration. With this kind of implantable sound sensor, a totally implantable hearing aid is feasible. A piezoresistive silicon accelerometer that is completely encapsulated with a thin silicon film and long flexible flex-circuit electrical cables were used for this study. The sensor is attached on the middle ear ossicles and measures the vibration transmitted from the tympanic membrane due to the sound in the ear canal. In this study, the sensor is fully characterized on a human cadaveric temporal bone preparation.

    View details for DOI 10.1007/s10544-007-9072-4

    View details for Web of Science ID 000250462200019

    View details for PubMedID 17574533

  • Scaling of amplitude-frequency-dependence nonlinearities in electrostatically transduced microresonators JOURNAL OF APPLIED PHYSICS Agarwal, M., Mehta, H., Candler, R. N., Chandorkar, S. A., Kim, B., Hopcroft, M. A., Melamud, R., Bahl, G., Yama, G., Kenny, T. W., Murmann, B. 2007; 102 (7)

    View details for DOI 10.1063/1.2785018

    View details for Web of Science ID 000250147700148

  • High resolution microresonator-based digital temperature sensor APPLIED PHYSICS LETTERS Jha, C. M., Bahl, G., Melamud, R., Chandorkar, S. A., Hopcroft, M. A., Kim, B., Agarwal, M., Salvia, J., Mehta, H., Kenny, T. W. 2007; 91 (7)

    View details for DOI 10.1063/1.2768629

    View details for Web of Science ID 000248866600117

  • Using the temperature dependence of resonator quality factor as a thermometer APPLIED PHYSICS LETTERS Hopcroft, M. A., Kim, B., Chandorkar, S., Melamud, R., Agarwal, M., Jha, C. M., Bahl, G., Salvia, J., Mehta, H., Lee, H. K., Candler, R. N., Kenny, T. W. 2007; 91 (1)

    View details for DOI 10.1063/1.2753758

    View details for Web of Science ID 000247819700074

  • Temperature-compensated high-stability silicon resonators APPLIED PHYSICS LETTERS Melamud, R., Kim, B., Chandorkar, S. A., Hopcroft, M. A., Agarwal, M., Jha, C. M., Kenny, T. W. 2007; 90 (24)

    View details for DOI 10.1063/1.2748092

    View details for Web of Science ID 000247305400116

  • A multiaxis force sensor for the study of insect biomechanics JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Bartsch, M. S., Federle, W., Full, R. J., Kenny, T. W. 2007; 16 (3): 709-718
  • Frequency stability of wafer-scale film encapsulated silicon based MEMS resonators SENSORS AND ACTUATORS A-PHYSICAL Kim, B., Candler, R. N., Hopcroft, M. A., Agarwal, M., Park, W., Kenny, T. W. 2007; 136 (1): 125-131
  • Wafer-scale fabrication of infrared detectors based on tunneling displacement transducers SENSORS AND ACTUATORS A-PHYSICAL Ajakaiye, A., Grade, J., Shin, C., Kenny, T. 2007; 134 (2): 575-581
  • Inhibition of metalloprotease botulinum serotype A from a pseudo-peptide binding mode to a small molecule that is active in primary neurons JOURNAL OF BIOLOGICAL CHEMISTRY Burnett, J. C., Ruthel, G., Stegmann, C. M., Panchal, R. G., Nguyen, T. L., Hermone, A. R., Stafford, R. G., Lane, D. J., Kenny, T. A., McGrath, C. F., Wipf, P., Stahl, A. M., Schmidt, J. J., Gussio, R., Brunger, A. T., Bavari, S. 2007; 282 (7): 5004-5014

    Abstract

    An efficient research strategy integrating empirically guided, structure-based modeling and chemoinformatics was used to discover potent small molecule inhibitors of the botulinum neurotoxin serotype A light chain. First, a modeled binding mode for inhibitor 2-mercapto-3-phenylpropionyl-RATKML (K(i) = 330 nM) was generated, and required the use of a molecular dynamic conformer of the enzyme displaying the reorientation of surface loops bordering the substrate binding cleft. These flexible loops are conformationally variable in x-ray crystal structures, and the model predicted that they were pivotal for providing complementary binding surfaces and solvent shielding for the pseudo-peptide. The docked conformation of 2-mercapto-3-phenylpropionyl-RATKML was then used to refine our pharmacophore for botulinum serotype A light chain inhibition. Data base search queries derived from the pharmacophore were employed to mine small molecule (non-peptidic) inhibitors from the National Cancer Institute's Open Repository. Four of the inhibitors possess K(i) values ranging from 3.0 to 10.0 microM. Of these, NSC 240898 is a promising lead for therapeutic development, as it readily enters neurons, exhibits no neuronal toxicity, and elicits dose-dependent protection of synaptosomal-associated protein (of 25 kDa) in a primary culture of embryonic chicken neurons. Isothermal titration calorimetry showed that the interaction between NSC 240898 and the botulinum A light chain is largely entropy-driven, and occurs with a 1:1 stoichiometry and a dissociation constant of 4.6 microM.

    View details for DOI 10.1074/jbc.M608166200

    View details for Web of Science ID 000244482000083

    View details for PubMedID 17092934

  • Acceleration sensitivity in beam-type electrostatic microresonators APPLIED PHYSICS LETTERS Agarwal, M., Park, K. K., Chandorkar, S. A., Candler, R. N., Kim, B., Hopcroft, M. A., Melamud, R., Kenny, T. W., Murmann, B. 2007; 90 (1)

    View details for DOI 10.1063/1.2426884

    View details for Web of Science ID 000243379900112

  • Long-term and accelerated life testing of a novel single-wafer vacuum encapsulation for MEMS resonators JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Candler, R. N., Hopcroft, M. A., Kim, B., Park, W., Melamud, R., Agarwal, M., Yama, G., Partridge, A., Lutz, M., Kenny, T. W. 2006; 15 (6): 1446-1456
  • Engineering MEMS resonators with low thermoelastic damping JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Duwel, A., Candler, R. N., Kenny, T. W., Varghese, M. 2006; 15 (6): 1437-1445
  • Optimal drive condition for nonlinearity reduction in electrostatic microresonators APPLIED PHYSICS LETTERS Agarwal, M., Chandorkar, S. A., Candler, R. N., Kim, B., Hopcroft, M. A., Melamud, R., Jha, C. M., Kenny, T. W., Murmann, B. 2006; 89 (21)

    View details for DOI 10.1063/1.2388886

    View details for Web of Science ID 000242220000087

  • Impact of geometry on thermoelastic dissipation in micromechanical resonant beams JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Candler, R. N., Duwel, A., Varghese, M., Chandorkar, S. A., Hopcroft, M. A., Park, W., Kim, B., Yama, G., Partridge, A., Lutz, M., Kenny, T. W. 2006; 15 (4): 927-934
  • A hybrid method for bubble geometry reconstruction in two-phase microchannels EXPERIMENTS IN FLUIDS Wang, E. N., Devasenathipathy, S., Lin, H., Hidrovo, C. H., Santiago, J. G., Goodson, K. E., Kenny, T. W. 2006; 40 (6): 847-858
  • Encapsulated submillimeter piezoresistive accelerometers JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Park, W., Partridge, A., Candler, R. N., Ayanoor-Vitikkate, V., Yama, G., Lutz, M., Kenny, T. W. 2006; 15 (3): 507-514
  • Two-phase microfluidics for semiconductor circuits and fuel cells HEAT TRANSFER ENGINEERING Hidrovo, C. H., Kramer, T. A., Wang, E. N., Vigneron, E., Steinbrenner, J. E., Koo, J. M., Wang, F. M., Fogg, D. W., Flynn, R. D., Lee, E. S., Cheng, C. H., Kenny, T. W., Eaton, J. K., Goodson, K. E. 2006; 27 (4): 53-63
  • Phase change phenomena in silicon microchannels INTERNATIONAL JOURNAL OF HEAT AND MASS TRANSFER Zhang, L. A., Wang, E. N., Goodson, K. E., Kenny, T. W. 2005; 48 (8): 1572-1582
  • Micromachined jets for liquid impingement cooling of VLSI chips (vol 13, pg 833, 2004) JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Wang, E. N., Zhang, L., Jiang, L. N., Koo, J. M., Maveety, J. G., Sanchez, E. A., Goodson, K. E., Kenny, T. W. 2004; 13 (6): 1072-1072
  • Micromachined jets for liquid impingement cooling of VLSI chips JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Wang, E. N., Zhang, L., Jiang, L. N., Koo, J. M., Maveety, J. G., Sanchez, E. A., Goodson, K. E., Kenny, T. W. 2004; 13 (5): 833-842
  • Comparison of thermal and piezoresistive sensing approaches for atomic force microscopy topography measurements APPLIED PHYSICS LETTERS King, W. P., Kenny, T. W., Goodson, K. E. 2004; 85 (11): 2086-2088

    View details for DOI 10.1063/1.1787160

    View details for Web of Science ID 000223923300073

  • Fatigue crack growth in micro-machined single-crystal silicon JOURNAL OF MATERIALS RESEARCH Renuart, E. D., Fitzgerald, A. M., Kenny, T. W., Dauskardt, R. H. 2004; 19 (9): 2635-2640
  • Nucleation and growth of vapor bubbles in a heated silicon microchannel JOURNAL OF HEAT TRANSFER-TRANSACTIONS OF THE ASME Wang, E. N., Devasenathipathy, S., Santiago, J. G., Goodson, K. E., Kenny, T. W. 2004; 126 (4): 497-497
  • Measurement system for low force and small displacement contacts JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Pruitt, B. L., Park, W. T., Kenny, T. W. 2004; 13 (2): 220-229
  • High speed particles separation using ultrasound for microTAS and lab-on-a-chip application. Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference Li, H., Kenny, T. 2004; 4: 2631-2634

    Abstract

    Engineers have long envisioned that a handheld portable blood diagnosis device would be able to give an accurate measurement of chemical content based on a very small sample in the shortest time possible. One of the immediate applications of such device is the point of care (POC) diagnosis system, whereby a single drop of human blood would determine his health status. However, a major technical challenge lies in the ability to separate different particles, which in the case of human blood, is to separate red and white blood cells and plasma in a quick, cheap, reliable device with low power consumption. In this paper, we present some preliminary results from our tests of ultrasound standing waves as a potential separation mechanism for blood cells. Also, we report on the study of the behavior of suspended particles of the size equivalent to a human cell under the influence of ultrasonic acoustic field, using micro particle image velocimetry (PIV) measurement technique. This provides the fundamental understanding and foundation of designing an integrated microchannel structure that can provide ultrasonic cell separation in the microscale regime. The study has shown promising results of successfully separating two different particles based on their sizes difference.

    View details for PubMedID 17270815

  • Measurements of cooling by room-temperature thermionic emission across a nanometer gap JOURNAL OF APPLIED PHYSICS Hishinuma, Y., Geballe, T. H., Moyzhes, B. Y., Kenny, T. W. 2003; 94 (7): 4690-4696

    View details for DOI 10.1063/1.1606852

    View details for Web of Science ID 000185420900071

  • Stress wave interference effects during fracture of silicon micromachined specimens EXPERIMENTAL MECHANICS Fitzgerald, A. M., Kenny, T. W., Dauskardt, R. H. 2003; 43 (3): 317-322
  • Single wafer encapsulation of MEMS devices IEEE TRANSACTIONS ON ADVANCED PACKAGING Candler, R. N., Park, W. T., Li, H. M., Yama, G., Partridge, A., Lutz, M., Kenny, T. W. 2003; 26 (3): 227-232
  • Design of piezoresistive MEMS-based accelerometer for integration with wireless sensing unit for structural monitoring JOURNAL OF AEROSPACE ENGINEERING Lynch, J. P., Partridge, A., Law, K. H., Kenny, T. W., Kiremidjian, A. S., Carryer, E. 2003; 16 (3): 108-114
  • Design of large deflection electrostatic actuators JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Grade, J. D., Jerman, H., Kenny, T. W. 2003; 12 (3): 335-343
  • Piezoresistive cantilevers and measurement system for characterizing low force electrical contacts SENSORS AND ACTUATORS A-PHYSICAL Pruitt, B. L., Kenny, T. W. 2003; 104 (1): 68-77
  • Embedment of structural monitoring algorithms in a wireless sensing unit STRUCTURAL ENGINEERING AND MECHANICS Lynch, J. P., Sundararajan, A., Law, K. H., Kiremidjian, A. S., Kenny, T., Carryer, E. 2003; 15 (3): 285-297
  • On-chip coupling of isoelectric focusing and free solution electrophoresis for multidimensional separations ANALYTICAL CHEMISTRY Herr, A. E., Molho, J. I., Drouvalakis, K. A., Mikkelsen, J. C., Utz, P. J., Santiago, J. G., Kenny, T. W. 2003; 75 (5): 1180-1187

    Abstract

    We have developed an acrylic microfluidic device that sequentially couples liquid-phase isoelectric focusing (IEF) and free solution capillary electrophoresis (CE). Rapid separation (<1 min) and preconcentration (73x) of species were achieved in the initial IEF dimension. Using full-field fluorescence imaging, we observed nondispersive mobilization velocities on the order of 20 microm/s during characterization of the IEF step. This transport behavior allowed controlled electrokinetic mobilization of focused sample bands to a channel junction, where voltage switching was used to repeatedly inject effluent from the IEF dimension into an ampholyte-based CE separation. This second dimension was capable of analyzing all fluid volumes of interest from the IEF dimension, as IEF was 'parked' during each CE analysis and refocused prior to additional CE analyses. Investigation of each dimension of the integrated system showed time-dependent species displacement and band-broadening behavior consistent with IEF and CE, respectively. The peak capacity of the 2D system was approximately 1300. A comprehensive 2D analysis of a fluid volume spanning 15% of the total IEF channel length was completed in less than 5 min.

    View details for DOI 10.1021/ac026239a

    View details for Web of Science ID 000181259300027

    View details for PubMedID 12641239

  • Process compatible polysilicon-based electrical through-wafer interconnects in silicon substrates JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Chow, E. M., Chandrasekaran, V., Partridge, A., Nishida, T., Sheplak, M., Quate, C. F., Kenny, T. W. 2002; 11 (6): 631-640
  • Design of atomic force microscope cantilevers for combined thermomechanical writing and thermal reading in array operation JOURNAL OF MICROELECTROMECHANICAL SYSTEMS King, W. P., Kenny, T. W., Goodson, K. E., Cross, G. L., Despont, M., Durig, U. T., Rothuizen, H., Binnig, G., Vettiger, P. 2002; 11 (6): 765-774
  • Vacuum thermionic refrigeration with a semiconductor heterojunction structure APPLIED PHYSICS LETTERS Hishinuma, Y., Moyzhes, B. Y., Geballe, T. H., Kenny, T. W. 2002; 81 (22): 4242-4244

    View details for DOI 10.1063/1.1523653

    View details for Web of Science ID 000179340800048

  • Evidence for van der Waals adhesion in gecko setae PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA Autumn, K., Sitti, M., Liang, Y. C., Peattie, A. M., Hansen, W. R., Sponberg, S., Kenny, T. W., Fearing, R., Israelachvili, J. N., Full, R. J. 2002; 99 (19): 12252-12256

    Abstract

    Geckos have evolved one of the most versatile and effective adhesives known. The mechanism of dry adhesion in the millions of setae on the toes of geckos has been the focus of scientific study for over a century. We provide the first direct experimental evidence for dry adhesion of gecko setae by van der Waals forces, and reject the use of mechanisms relying on high surface polarity, including capillary adhesion. The toes of live Tokay geckos were highly hydrophobic, and adhered equally well to strongly hydrophobic and strongly hydrophilic, polarizable surfaces. Adhesion of a single isolated gecko seta was equally effective on the hydrophobic and hydrophilic surfaces of a microelectro-mechanical systems force sensor. A van der Waals mechanism implies that the remarkable adhesive properties of gecko setae are merely a result of the size and shape of the tips, and are not strongly affected by surface chemistry. Theory predicts greater adhesive forces simply from subdividing setae to increase surface density, and suggests a possible design principle underlying the repeated, convergent evolution of dry adhesive microstructures in gecko, anoles, skinks, and insects. Estimates using a standard adhesion model and our measured forces come remarkably close to predicting the tip size of Tokay gecko seta. We verified the dependence on size and not surface type by using physical models of setal tips nanofabricated from two different materials. Both artificial setal tips stuck as predicted and provide a path to manufacturing the first dry, adhesive microstructures.

    View details for DOI 10.1073/pnas.192252799

    View details for Web of Science ID 000178187000048

    View details for PubMedID 12198184

  • Subcritical crack growth in single-crystal silicon using micromachined specimens JOURNAL OF MATERIALS RESEARCH Fitzgerald, A. M., Iyer, R. S., Dauskardt, R. H., Kenny, T. W. 2002; 17 (3): 683-692
  • Measurements and modeling of two-phase flow in microchannels with nearly constant heat flux boundary conditions JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Zhang, L., Koo, J. M., Jiang, L., Asheghi, M., Goodson, K. E., Santiago, J. G., Kenny, T. W. 2002; 11 (1): 12-19
  • Characterization of a two-dimensional cantilever array with through-wafer electrical interconnects APPLIED PHYSICS LETTERS Chow, E. M., Yaralioglu, G. G., Quate, C. F., Kenny, T. W. 2002; 80 (4): 664-666
  • Electron spin relaxation near a micron-size ferromagnet PHYSICAL REVIEW LETTERS Stipe, B. C., Mamin, H. J., Yannoni, C. S., Stowe, T. D., Kenny, T. W., Rugar, D. 2001; 87 (27)

    Abstract

    Magnetic resonance force microscopy was used to study the behavior of small ensembles of unpaired electron spins in silica near a micrometer-size ferromagnetic tip. Using a cantilever-driven spin manipulation protocol and a magnetic field gradient greater than 10(5) T/m, signals from as few as 100 net spins within a 20 nm thick resonant slice could be studied. A sixfold increase in the spin-lattice relaxation rate was found within 800 nm of the ferromagnet, while no effect due to silica surface proximity was detected. The results are interpreted in terms of Larmor-frequency magnetic field fluctuations emanating from the ferromagnet.

    View details for DOI 10.1103/PhysRevLett.87.277602

    View details for Web of Science ID 000173040800056

    View details for PubMedID 11800915

  • A high-stiffness axial resonant probe for atomic force microscopy JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Harley, J. A., Kenny, T. W. 2001; 10 (3): 434-441
  • A high-precision, wide-bandwidth micromachined tunneling accelerometer JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Liu, C. H., Kenny, T. W. 2001; 10 (3): 425-433
  • Noncontact friction and force fluctuations between closely spaced bodies PHYSICAL REVIEW LETTERS Stipe, B. C., Mamin, H. J., Stowe, T. D., Kenny, T. W., Rugar, D. 2001; 87 (9)

    Abstract

    Noncontact friction between a Au(111) surface and an ultrasensitive gold-coated cantilever was measured as a function of tip-sample spacing, temperature, and bias voltage using observations of cantilever damping and Brownian motion. The importance of the inhomogeneous contact potential is discussed and comparison is made to measurements over dielectric surfaces. Using the fluctuation-dissipation theorem, the force fluctuations are interpreted in terms of near-surface fluctuating electric fields interacting with static surface charge.

    View details for DOI 10.1103/PhysRevLett.87.096801

    View details for Web of Science ID 000170698000030

    View details for PubMedID 11531586

  • Nanometer-Scale Force Sensing with MEMS Devices IEEE SENSORS JOURNAL Kenny, T. 2001; 1 (2): 148-157
  • Refrigeration by combined tunneling and thermionic emission in vacuum: Use of nanometer scale design APPLIED PHYSICS LETTERS Hishinuma, Y., Geballe, T. H., Moyzhes, B. Y., Kenny, T. W. 2001; 78 (17): 2572-2574
  • Magnetic dissipation and fluctuations in individual nanomagnets measured by ultrasensitive cantilever magnetometry PHYSICAL REVIEW LETTERS Stipe, B. C., Mamin, H. J., Stowe, T. D., Kenny, T. W., Rugar, D. 2001; 86 (13): 2874-2877

    Abstract

    Cantilever magnetometry with moment resolution better than 10(4)micro(B) was used to study individual nanomagnets. By using the fluctuation-dissipation theorem to interpret measurements of field-induced cantilever damping, the low frequency spectral density of magnetic fluctuations could be determined with resolution better than 1micro(B) Hz-1/2. Cobalt nanowires exhibited significant magnetic dissipation and the associated magnetic fluctuations were found to have 1/f frequency dependence. In individual submicron rare-earth alloy magnets, the dissipation/fluctuation was very small and not distinguishable from that of a bare silicon cantilever.

    View details for Web of Science ID 000167693000044

    View details for PubMedID 11290061

  • Optimization of turn geometries for microchip electrophoresis ANALYTICAL CHEMISTRY Molho, J. I., Herr, A. E., Mosier, B. P., Santiago, J. G., Kenny, T. W., Brennen, R. A., Gordon, G. B., Mohammadi, B. 2001; 73 (6): 1350-1360
  • Adventures in attonewton force detection APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING Rugar, D., Stipe, B. C., Mamin, H. J., Yannoni, C. S., Stowe, T. D., Yasumura, K. Y., Kenny, T. W. 2001; 72: S3-S10
  • Atomic force microscope cantilevers for combined thermomechanical data writing and reading APPLIED PHYSICS LETTERS King, W. P., Kenny, T. W., Goodson, K. E., Cross, G., Despont, M., Durig, U., Rothuizen, H., Binnig, G. K., Vettiger, P. 2001; 78 (9): 1300-1302
  • Adhesive force of a single gecko foot-hair NATURE Autumn, K., Liang, Y. A., Hsieh, S. T., Zesch, W., Chan, W. P., Kenny, T. W., Fearing, R., Full, R. J. 2000; 405 (6787): 681-685

    Abstract

    Geckos are exceptional in their ability to climb rapidly up smooth vertical surfaces. Microscopy has shown that a gecko's foot has nearly five hundred thousand keratinous hairs or setae. Each 30-130 microm long seta is only one-tenth the diameter of a human hair and contains hundreds of projections terminating in 0.2-0.5 microm spatula-shaped structures. After nearly a century of anatomical description, here we report the first direct measurements of single setal force by using a two-dimensional micro-electromechanical systems force sensor and a wire as a force gauge. Measurements revealed that a seta is ten times more effective at adhesion than predicted from maximal estimates on whole animals. Adhesive force values support the hypothesis that individual seta operate by van der Waals forces. The gecko's peculiar behaviour of toe uncurling and peeling led us to discover two aspects of setal function which increase their effectiveness. A unique macroscopic orientation and preloading of the seta increased attachment force 600-fold above that of frictional measurements of the material. Suitably orientated setae reduced the forces necessary to peel the toe by simply detaching above a critical angle with the substratum.

    View details for Web of Science ID 000087465800046

    View details for PubMedID 10864324

  • 1/F noise considerations for the design and process optimization of piezoresistive cantilevers JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Harley, J. A., Kenny, T. W. 2000; 9 (2): 226-235
  • Quality factors in micron- and submicron-thick cantilevers JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Yasumura, K. Y., Stowe, T. D., Chow, E. M., Pfafman, T., Kenny, T. W., Stipe, B. C., Rugar, D. 2000; 9 (1): 117-125
  • Electroosmotic capillary flow with nonuniform zeta potential ANALYTICAL CHEMISTRY Herr, A. E., Molho, J. I., Santiago, J. G., Mungal, M. G., Kenny, T. W., Garguilo, M. G. 2000; 72 (5): 1053-1057
  • Electroosmotic capillary flow with nonuniform zeta potential Analytical chemistry Herr, A. E., Molho, J. I., Santiago, J. G., Mungal, M. G., Kenny, T. W., Garguilo, M. G. 2000; 72 (5): 1053-7

    Abstract

    The present work is an analytical and experimental study of electroosmotic flow (EOF) in cylindrical capillaries with nonuniform wall surface charge (zeta-potential) distributions. In particular, this study investigates perturbations of electroosmotic flow in open capillaries that are due to induced pressure gradients resulting from axial variations in the wall zeta-potential. The experimental inquiry focuses on electroosmotic flow under a uniform applied field in capillaries with an EOF-suppressing polymer adsorbed onto various fractions of the total capillary length. This fractional EOF suppression was achieved by coupling capillaries with substantially different zeta-potentials. The resulting flow fields were imaged with a nonintrusive, caged-fluorescence imaging technique. Simple analytical models for the velocity field and rate of sample dispersion in capillaries with axial zeta-potential variations are presented. The resulting induced pressure gradients and the associated band-broadening effects are of particular importance to the performance of chemical and biochemical analysis systems such as capillary electrokinetic chromatography and capillary zone electrophoresis.

    View details for PubMedID 10739211

  • Silicon dopant imaging by dissipation force microscopy APPLIED PHYSICS LETTERS Stowe, T. D., Kenny, T. W., Thomson, D. J., Rugar, D. 1999; 75 (18): 2785-2787
  • An integrated controller for tunnel sensors IEEE JOURNAL OF SOLID-STATE CIRCUITS Partridge, A., Reynolds, J. K., Grade, J. D., Kane, B. J., Maluf, N. I., Kovacs, G. T., Kenny, T. W. 1999; 34 (8): 1099-1107
  • High-sensitivity piezoresistive cantilevers under 1000 angstrom thick APPLIED PHYSICS LETTERS Harley, J. A., Kenny, T. W. 1999; 75 (2): 289-291
  • Intrinsic-carrier thermal runaway in silicon microcantilevers MICROSCALE THERMOPHYSICAL ENGINEERING Chui, B. W., Asheghi, M., Ju, Y. S., Goodson, K. E., Kenny, T. W., Mamin, H. J. 1999; 3 (3): 217-228
  • Ultrahigh-density atomic force microscopy data storage with erase capability APPLIED PHYSICS LETTERS Binnig, G., Despont, M., Drechsler, U., Haberle, W., Lutwyche, M., Vettiger, P., Mamin, H. J., Chui, B. W., Kenny, T. W. 1999; 74 (9): 1329-1331
  • Technique for measurement of the noise of a sensor in the presence of large background signals REVIEW OF SCIENTIFIC INSTRUMENTS Barzilai, A., VanZandt, T., Kenny, T. 1998; 69 (7): 2767-2772
  • Characterization of a high-sensitivity micromachined tunneling accelerometer with micro-g resolution JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Liu, C. H., Barzilai, A. M., Reynolds, J. K., Partridge, A., Kenny, T. W., Grade, J. D., Rockstad, H. K. 1998; 7 (2): 235-244
  • Independent detection of vertical and lateral forces with a sidewall-implanted dual-axis piezoresistive cantilever APPLIED PHYSICS LETTERS Chui, B. W., Kenny, T. W., Mamin, H. J., Terris, B. D., Rugar, D. 1998; 72 (11): 1388-1390
  • Low-stiffness silicon cantilevers with integrated heaters and piezoresistive sensors for high-density AFM thermomechanical data storage JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Chui, B. W., Stowe, T. D., Ju, Y. S., Goodson, K. E., Kenny, T. W., Mamin, H. J., Terris, B. D., Ried, R. P., Rugar, D. 1998; 7 (1): 69-78
  • Attonewton force detection using ultrathin silicon cantilevers APPLIED PHYSICS LETTERS Stowe, T. D., Yasumura, K., Kenny, T. W., Botkin, D., Wago, K., Rugar, D. 1997; 71 (2): 288-290
  • Fabrication of collimating grids for an x-ray solar telescope using LIGA methods MICROSYSTEM TECHNOLOGIES Brennen, R. A., Hecht, M. H., Wiberg, D. V., MANION, S. J., Bonivert, W. D., Hruby, J. M., Scholz, M. L., Stowe, T. D., Kenny, T. W., Jackson, K. H., Malek, C. K. 1997; 3 (3): 91-96
  • Low-stiffness silicon cantilevers for thermal writing and piezoresistive readback with the atomic force microscope APPLIED PHYSICS LETTERS Chui, B. W., Stowe, T. D., Kenny, T. W., Mamin, H. J., Terris, B. D., Rugar, D. 1996; 69 (18): 2767-2769
  • Micromachined infrared sensors using tunneling displacement transducers REVIEW OF SCIENTIFIC INSTRUMENTS Kenny, T. W., Reynolds, J. K., Podosek, J. A., Vote, E. C., Miller, L. M., Rockstad, H. K., Kaiser, W. J. 1996; 67 (1): 112-128
  • WIDE-BANDWIDTH ELECTROMECHANICAL ACTUATORS FOR TUNNELING DISPLACEMENT TRANSDUCERS JOURNAL OF MICROELECTROMECHANICAL SYSTEMS Kenny, T. W., Kaiser, W. J., Rockstad, H. K., Reynolds, J. K., Podosek, J. A., Vote, E. C. 1994; 3 (3): 97-104

Conference Proceedings


  • Development and characterization of a TES optical imaging array for astrophysics applications Burney, J., Bay, T. J., Brink, P. L., Cabrera, B., Castle, J. P., Romani, R. W., Tomada, A., Nam, S. W., Miller, A. J., Martinis, J., Wang, E., Kenny, T., Young, B. A. ELSEVIER SCIENCE BV. 2004: 533-536
  • Closed-loop electroosmotic microchannel cooling system for VLSI circuits Jiang, L. N., Mikkelsen, J., Koo, J. M., Huber, D., Yao, S. H., Zhang, L., Zhou, P., Maveety, J. G., Prasher, R., Santiago, J. G., Kenny, T. W., Goodson, K. E. IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC. 2002: 347-355
  • Integration of through-wafer interconnects with a two-dimensional cantilever array Chow, E. M., Soh, H. T., Lee, H. C., Adams, J. D., Minne, S. C., Yaralioglu, G., Atalar, A., Quate, C. F., Kenny, T. W. ELSEVIER SCIENCE SA. 2000: 118-123
  • Fracture toughness and crack growth phenomena of plasma-etched single crystal silicon Fitzgerald, A. M., Dauskardt, R. H., Kenny, T. W. ELSEVIER SCIENCE SA. 2000: 194-199
  • Rapid biochemical detection and differentiation with magnetic force microscope cantilever arrays Rudnitsky, R. G., Chow, E. M., Kenny, T. W. ELSEVIER SCIENCE SA. 2000: 256-262
  • Packaging a piezoresistive pressure sensor to measure low absolute pressures over a wide sub-zero temperature range Reynolds, J. K., Catling, D., Blue, R. C., Maluf, N. I., Kenny, T. ELSEVIER SCIENCE SA. 2000: 142-149
  • Torsional force probes optimized for higher order mode suppression STOWE, T., Yasumura, K., Pfafman, T., Kenny, T., Botkin, D., Rugar, D. I E E E. 1997: 141-144
  • A miniature, high-sensitivity, electron tunneling accelerometer Rockstad, H. K., Tang, T. K., Reynolds, J. K., Kenny, T. W., Kaiser, W. J., Gabrielson, T. B. ELSEVIER SCIENCE SA. 1996: 227-231
  • SENSORS BASED ON TUNNELING DISPLACEMENT TRANSDUCERS - DESIGN, APPLICATIONS, AND LIMITATIONS Kenny, T. AMER CHEMICAL SOC. 1995: 50-COLL