DE CALLAFON, RAYMOND A
Faculty
callafon@ucsd.edu

Research Interests

Research Unit: Information Storage

Professor De Callafon is interested in modeling and control applications that involve mechanical, servo and structural systems. He uses system identification techniques to develop models to simulate, monitor, predict and control a variety of dynamical systems. System identification is an interactive and systematic way of modeling system behavior by estimating dynamic models on the basis of experimental input/output data. Due to inherent experiment based nature of his research, the techniques can be applied to a wide variety of dynamical systems and include problems such as dynamic modeling for control, health monitoring and model validation. De Callafon is working with UCSD's Center for Magnetic Recording Research to model hard disk drives in order to develop robust servo control algorithms. He studies disk drive disturbances, such as windage, and product variability to improve functionality. De Callafon also looks at flutter behavior in light weight airplane wings, creating health monitoring models that can predict failure based on monitoring and feedback stabilization. In the process, input and output data are gathered and it is determined of the information could have been produced by the model. If not, then the system's properties have changed or it is about to fail. In addition, De Callafon uses his techniques to develop dynamic models for vibration and noise control. This research has structural applications and could be used to control a building's response during an earthquake, as well as active noise control to model, predict and control sound produced by devices such as ventilation fans. In this case, a counter noise is produced to cancel out the fan's noise. His research has been applied to control a number of electromechanical systems such as a CD-ROM player and the positioning mechanism found in a wafer stepper.


JIN, SUNGHO
Faculty-Emeritus
sujin@ucsd.edu

Research Interests

Research Unit: Information Storage

Professor Jin is a world-renowned researcher in the field of functional materials used in applications ranging from magnetic devices and electronic devices to optical telecommunications networks. Jin is involved in R&D of micro-electro-mechanical-system (MEMS) devices and materials; exploratory bio-materials and devices; carbon nanotube materials on which future nano-scale devices can be based; and sensor/actuator devices and technologies. Jin has also been a pioneer in the development of high-temperature superconductor materials, colossal magnetoresistance (CMR) materials, diamond film thinning techniques, anisotropic conductive polymers, and new, environmentally safe, lead-free solders that he has championed since the early 1990s. He also invented magnet sensor materials now widely used in anti-theft security tags in retail stores. With roughly 170 patents to his name, Jin can discuss intellectual property issues and is developing a course on inventions and patents.


LUBARDA, VLADO
Faculty-Adjunct
vlubarda@ucsd.edu

Research Interests

Research Unit: Information Storage

Professor Lubarda is interested in a number of unique aspects related to solids, including elasticity, plasticity, dislocations, damage mechanics, and fracture mechanics. He applies his extensive knowledge of elastoplasticity theory, the subject of his latest book, to better understand and predict the behavior of materials. A material that is elastic bends under certain loads and then returns to its original shape. An elastoplastic solid will bend and remain in a deformed position. Often times, this characteristic is desirable. In creating automobiles for example, the steel must be shaped and pressed to form certain shapes while at the same time retaining strength and reliability. It is a matter of finding the balance between deformation and strength, and knowing a solid's limits. In other cases, elastoplasticity is undesirable and may compromise the structural integrity of a solid (e.g. buildings and bridges). Lubarda has worked with organizations such as the NSF, the U.S. Army, and ALCOA (Aluminum Company of America) to provide a greater understanding of solid behaviors under various conditions. He studied fundamental aspects of mathematical and physical theories of elastoplasticity with funding from NSF. For the Army he did research in damage and rock mechanics to gauge the effectiveness of underground bunkers in protecting against outside penetration. And for ALCOA he analyzed dislocations and other imperfections in aluminum alloys (such as Al-Cu alloys) to improve the mechanical properties related to their ductility and strength.


TALKE, FRANK E
Faculty
ftalke@ucsd.edu

Research Interests

Research Unit: Information Storage

In the last 55 years, areal density of data storage in rigid disks has increased 100 million fold to more than 500 Gbits (500 billion bits) per inch square. The next mile stone, 1 Tbit/square inch, is near and researchers are working on 10 Terabits (ten trillion bits) per square inch areal density. New techniques are required to design devices with moving parts orders of magnitude smaller than those typically encountered by mechanical engineers. As head of the Tribology and Mechanics Lab at UCSD’s Center for Magnetic Recording Research, Professor Talke is at the forefront of research that takes places where borders blur between mechanics, physics, and chemistry. For example, storage density of one Terabit/square inch will require read-write heads in a disk drive to fly within one or two nanometers from the disk media. Active flying height control by thermal activation of the magnetic read/write head is one of the possibilities to achieve this. A flying height of one or two nanometers is so close that adhesion forces between slider and disk must be considered, that lubricant-materials interactions (stiction) come into play, and that the slightest mechanical disturbance can cause the slider to lose the desired track. Areas of expertise for Talke are the mechanics of the head/disk interface in tape and disk drives, the tribology and surface interactions of heads and recording media, strategies to reduce the flying height, the physics and chemistry of lubricants, modeling and analysis of the flying characteristics of sliders, and high precision instrumentation to assess and measure slider motion, slider dynamics and wear at the head disk interface.