David Field - US grants

An ecological approach to computational vision is developed which investigates the relation between the statistical structure of the visual environment and the properties of the mammalian visual pathway. A specific theory will be developed and tested based on the premise that the goal of early visual processing is to produce a response to the visual environment that is both sparse (a minimum number of 'active' cells) and distributed (all cells have equal response probability). The proposed studies will be directed along three parallel lines. 1) A general theory will be developed to account for how sparse distributed codes can be produced given an environment with statistical regularity. 2) Using computational models of the mammalian visual system this theory will be tested by investigating whether natural scenes have the necessary and sufficient conditions to produce sparse distributed activity 3) Using computational modeling and experiments involving human psycho-physics, specific hypotheses about the advantages of sparse distributed codes will be tested. By relating the behavior of cell populations to the statistical structure of the visual environment, we expect to gain a better insight into the nature of how the mammalian visual system functions under natural conditions. The computational studies along with proposed studies related to the perception of blur in natural environments, will provide a means for relating visual dysfunction (e.g., low vision) to underlying clinical abnormalities.

A thermal-source field-emission SEM (FESEM) will be acquired to perform structural characterization on nano-scale and nano-crystalline materials. Specifically, projects in the development and optimization of functional thin films will be enabled by this instrument. The WSU MEMS based engine which operates on layers of piezo-electric films (lead zirconate titanate, PZT) currently produces power sufficient to operate small electrical devices (such as a wrist-watch). Optimization of the structures through strategic processing will boost the power output to tens of watts. This will be accomplished through complete structural characterization of the grain structure and local crystallographic texture. Such analysis is only possible through electron backscatter diffraction (EBSD) on an FESEM. Cu interconnects for integrated circuits have enabled continued miniaturization of the interconnect structure that now requires maximum spatial resolution for adequate crystallographic analysis of the structures. Local crystallogaprhic texture and grain boundary structure (including twin boundary content and morphology) are important for improved manufacturability and resistance to electromigration that now has driving forces on the order of 106 A/cm2. Finally, mechanical properties of nanocrystalline materials are controlled by mechanisms that are not considered to be important in conventional polycrystals. Investigation of the mechanisms controlling the performance of nanocrystalline metals requires complete structural characterization on the scale of the crystallites that can be accomplished using the FESEM. The instrument will add significant new strength to existing funded research areas such as MEMS, structures and properties of metal films for microelectronics applications, the study of radiation induced structures in wide bandgap materials, and nano-materials for biological applications.

In addition to the several graduate students that will be primary users of the FESEM, there will be access to the instrumentation for various undergraduate students working on specific topic areas under one of the principal or ancillary users, or as part of the requirements to complete undergraduate research projects. The instrument will be used by undergraduate students in a Materials Characterization Laboratory course, and will be highly utilized in our NSF sponsored REU program in Characterization of Advanced Materials (in which about 50% of the participants are women or minority students). The proposed FESEM can easily be adapted for remote operation and will be remotely operated for training purposes. This will benefit existing courses on our main campus. In the future, this remote access will be offered to the various high school and community colleges in Washington State that may have an interest.



A field-emission scanning electron microscope (FESEM) will be purchased for use in characterization of nano-scale materials. Advances in SEM technology have enabled superior imaging resolution, via the field emission electron source. Electron back-scatter diffraction (EBSD) analysis enables crystallographic information (phase and orientation) to be obtained in the SEM. These enhancements have empowered researchers to embark on an entirely new class of research that previously could not be reasonably approached with any other analytical instrumentation. Fine structures in crystalline materials ultimately control the macroscopic properties of materials. The FESEM will be used to develop microstructure-property relationships and processing/synthesis-microstructure relationships in several key application areas. It will be used to further develop and optimize the world's smallest engine currently in development at WSU. This micro-electromechanical system (MEMS) device is only millimeters in total dimension, and can generate power on the order of tens of watts. The power-generating films in this device are sub-micron in thickness, with structural features on the order of 50 nm. Local structure analysis can only be performed using an FESEM in concert with EBSD technology. Additional major research projects require the characterization power of the FESEM. Mechanical properties of nanocrystalline materials are generally superior to conventional materials. Optimizing the structures of such materials will allow for stronger, more efficient materials that will result in lighter, stronger materials for use in automotive, aerospace, and structural applications. Finally, modern integrated circuits require highly optimized interconnect structure with minimum feature sizes on the order of 100 nm and shrinking with each new generation. This research will continue to further the understanding of optimal structures, particularly in the copper interconnect wires, that will lead to increased speed and reliability of computer chips.

In addition to the several graduate students that will be primary users of the FESEM, there will be access to the instrumentation for various undergraduate students working on specific topic areas under one of the principal or ancillary users, or as part of the requirements to complete undergraduate research projects. The instrument will be used by undergraduate students in a Materials Characterization Laboratory course, and will be highly utilized in our NSF sponsored REU program in Characterization of Advanced Materials (in which about 50% of the participants are women or minority students). The proposed FESEM can easily be adapted for remote operation and will be remotely operated for training purposes. This will benefit existing courses on our main campus. In the future, this remote access will be offered to the various high school and community colleges in Washington State that may have an interest.

0502387
Field

The International Research Fellowship Program enables U.S. scientists and engineers to conduct three to twenty-four months of research abroad. The program's awards provide opportunities for joint research, and the use of unique or complementary facilities, expertise and experimental conditions abroad.

This award will support a twenty-two-month research fellowship by Dr. David B. Field to work with Dr. Dimitri Gutierrez at Instituto del Mar del Peru in Callao, Peru, and Dr. Christina Ravel at the University of California, Santa Cruz.


The tropical Pacific is a key component in the global climate system and has far reaching societal impacts. Paleoclimate records are needed to examine ocean variability beyond the El Nino Southern Oscillation (ENSO) timescale. Since different modes of variability have unique horizontal and vertical patterns, determining the mechanisms of change is possible through reconstructing changes in the vertical structure of the water column with planktonic and benthic foraminifera, as well as through comparison of records between different locations. Laminated sediments from the Peruvian shelf region are ideally suited to test hypotheses concerning the role of the eastern tropical Pacific (ETP) and intermediate water circulation in decadal- to-centennial-scale variability, the ecosystem response to such ocean variability, and the effects of anthropogenic activity. This proposal outlines an international effort to develop paleoceanographic time series resolving decadal-scale changes over the last 1,000 years from laminated sediments off Peru. This effort will take place at IMARPE (Instituto del Mar del Peru) in Callao, Peru in direct collaboration with Dr. Dimitri Gutierrez and other scientists from Peru, Chile, France, and Mexico. In the period of time spent at the University of California, Santa Cruz, the PIs will investigate the sources of high frequency climate variability in the Eastern tropical Pacific.

Characterizing the natural modes of climate variability is essential to understanding climate and ecosystem processes, detecting anthropogenic influences, and identifying and predicting future changes and risks. The time series of this research will serve as important constraints on the role of the ETP in modifying ENSO, decadal-to-centennial climate variability, and 20th century warming. Understanding the mechanisms of change has policy implications for assessing the potential environmental and ecological risks and uncertainties associated with future natural and/or anthropogenic change.

Engineering - Materials Science (57)

This project is focused on increasing student involvement in active undergraduate research activities across engineering disciplines, primarily in the freshmen and sophomore years. This is being done by developing a two stage program. The first aspect is an intensive summer camp to provide basic information about research skills and techniques that are broadly applicable to science and engineering. After successfully completing the week-long summer program, students enter the second stage of the program; a mentoring and seminar program during the school year to pair students with faculty on campus. Faculty members from four engineering disciplines are participating in both the camp and school year programs. Up to 20 students per year are participating in the program. The program is creating new teaching strategies while providing a core group of faculty from several engineering programs an opportunity to develop expertise in a unique format of education not commonly carried out at universities. The program is being evaluated via a control group to assess measurable outcomes that include increased student participation in research and retention in engineering.

EEC-0754370
Cecilia D. Richards

This three year REU Site program will expose ten undergraduate students each year to basic concepts in the emerging field of multiscale science and engineering and will provide them with intensive hands-on research experience. The students will have an opportunity to work in a multidisciplinary environment with a range of mentors (faculty, post docs and graduate students) on projects ranging from material processing, fabrication and testing, microfluidic and MEMS devices, nanoindentation and atomic force measurements, to introduction to design algorithms for nano-macro-structured materials, molecular dynamics, dislocation dynamics, mesoscale analyses for deformation and flow in nano and macro structures.

Students will participate in a weekly forum where they will give short overviews/updates of their projects and develop their oral technical communication skills. They will also participate in a joint activity with the NSF sponsored Engineering Education Research Center (EERC) to gain exposure to another emerging area of engineering research. The participants will disseminate the results of their independent research projects in a campus wide poster session.

Recent developments in nanostructures have brought to light exceptional electromagnetic, thermal and optical properties of a class of foam-like nanostructures formed of disordered intertwined structural units (nanowires, nanobelts, nanotubes). Such disordered assemblies are named turfs. Applications include thermal switches, flat panel displays, hard discs drives, and, chemical and biological sensors.
Although the mechanical properties are usually not the primary service characteristic of turfs, they are nevertheless of paramount importance. Irrespective of application, the turfs are often subjected to mechanical loads, either as service load as in thermal switches, or, as accidental contacts. Under externally forced deformation, the nano-topology of the turf changes, which, in turn, affects all the other effective properties: electrical, thermal, optical, sensing and permeability.
We will develop an integrated approach to the problem: multiscale modeling, nanomechanical experiments, and, nanostructure characterization, with the following objectives:
Understanding and quantification of the behavior of turfs as materials on the basis of the physical and geometrical properties of the individual units and their collective behavior in the assembly.
Development of the nanoscale characterization methods that reveal the relevant parameters of the nanostructure.
Practical technological impact of the project is that the results will enable rational design of nanoturfs tailored for particular application in sensors, thermal switches and other devices. The REU component of the program is carefully structured and includes assessment methods, developed and proven at the Center for Teaching and Learning at WSU. Our pilot student mentoring program will provide graduate students with mentoring experience a skill that PhD graduates need, but is sorely missing in most graduate programs.

TECHNICAL SUMMARY: This research ultimately aims at developing a more complete understanding of triple junction character and how the geometric character of the triple junction relates to the observed properties and local character of the microstructure. A triple-junction distribution function (3DF) will be developed that characterizes the complete space of triple junctions without assuming a priori that a certain type of boundary or junction is special. 3DF measurements will be obtained using grain-boundary engineered Cu and the Inconel alloys 600 and 617. The 3DF will include the functional dependence on crystallite lattice misorientations, triple line orientations with respect to the lattice and grain-boundary plane orientations. The complete function lies in an extremely large space making statistically reliable measurements difficult to obtain. This problem will be overcome by focusing on triple junctions associated with twin boundaries, thereby reducing the dimensionality of the function. The proposed analysis applies specifically to grain-boundary engineered alloys that have a preponderance of coherent twins, but the technique can be easily extended to include all triple junctions. Microstructural characterization to this extent has yet to be employed in investigations of grain-boundary engineering and offers a real opportunity to gain a more complete understanding of the mechanisms involved in formation of triple junctions. Finally, carbide and void distributions in alloy 617 will be characterized using the 3DF.

NON-TECHNICAL SUMMARY: Polycrystalline materials subjected to stress at high temperatures for long periods of time often develop brittle phases or even voids and cracks in certain regions that are most susceptible to this type of microstructural damage. Such materials are used in conventional fossil-fuel and nuclear power plants, for example, and these alloys are the primary focus of this project. To be able to predict the lifetime of such materials, the distribution of grain boundaries and their intersections (triple junctions), where damage is most likely to occur, should be quantified. To this end, the difficulty in measuring triple-junction distributions has prevented reliable characterization of these features in real materials. The present work focuses on the development of a triple junction distribution function that will enable researchers to properly characterize regions that are most susceptible to damage and distinguish them from those that are least susceptible. With this information, more realistic predictions of the useful life of engineering materials can be made, and process engineers will be able to design fabrication procedures that result in the most damage resistant microstructures. Undergraduate and graduate students will be involved through experience in the laboratory and development of curriculum.

This Research Experience for Undergraduates (REU) Site focuses on characterization of advanced materials. Under the supervision of faculty from Mechanical and Materials Engineering, Chemistry, and Civil Engineering, undergraduate student participants utilize tools such as electron microscopy, scanning probe microscopy, infrared spectroscopy, nanoindentation, and other methods to understand the relationships between the processing, structure and properties of a wide range of materials. Ten undergraduate students, including freshmen and sophomores, from a wide variety of disciplines and schools are recruited nationwide every year for the ten-week summer research experience. The Site also adds new faculty members over its life to encourage starting faculty to provide significant undergraduate research experiences.

In addition to independent projects, students participate in a series of short workshops on research skills and presentation skills to enhance their ability to communicate their work to broad audiences. Research projects are presented at a campus-wide poster session at the end of the summer with up to 100 participants.

This REU Site is suppported by the Department of Defense in partnership with the NSF REU program.