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2001-2002 University Research Professors

Chi-Sing Man: Heavy Into Light Metals

by Jeff Worley

Let's start with a platitude: A chain is only as strong as its weakest link.

In the Department of Mathematics at the University of Kentucky, Chi-Sing Man's work on the microstructures of aluminum and titanium may call this aphorism to mind.

"To the naked eye, the polished surface of a metal sheet appears as a clear, unbroken continuum," says Man, who came to UK from Johns Hopkins University in 1985. "But looking into his microscope, a metallographer can see the underlying polycrystalline structure. The orientation of the crystals, or grains—their texture and how they arrange themselves together—exerts a strong influence on the mechanical behavior of the larger structure."

Photo of Chi-Sing Man and Thomas WidigerChi-Sing Man and Thomas Widiger, two of this year's University Research Professors

Apart from the pure science interest in understanding these sub-structures, such work might lead to actually saving people's lives. For instance, the National Transportation Safety Board determined that an undetected metallurgic defect in a titanium fan disc of the No. 2 engine caused the crash of a United Airlines DC-10 in Sioux City, Iowa, in 1989.

Man explains that the tiny grains which make up a piece of metal are simply imitating nature. Ice and rocks are made up of tiny crystals that assume different orientations in space. Their shape and size and the way they fit together determine the discernable object's shape and strength. Think of a snowball. Its "throwability" is dependent on how our hands shape and pressure—or re-orient—the billions of ice crystals that comprise the frozen globe.

It's clear that microscopic properties of materials are crucial to their flexibility and durability, but what does this have to do with math?

Man explains: "Sound mathematical models that predict the response of these materials to stress, and enable accurate measurement of material properties, are of clear interest and importance to industries like Commonwealth Aluminum and GE Aircraft Engines that have partnered with federal agencies such as the Department of Energy and the National Science Foundation to co-sponsor my research."

A fundamental problem, he says, is to determine what's going on at the microscopic level of a metal and how that composition affects the behavior of the material in a mathematically tractable way. "It is clearly impractical to measure the orientation and other microscopic properties of each individual crystal in a polycrystalline material. Instead, a statistical approach must be used in which these microscopic properties can be described by a probability distribution. A sound mathematical model enables us to both measure the material properties and to predict the mechanical behavior of materials once the microstructural properties are known," Man says.

"Chi-Sing's work is bringing to the University of Kentucky exactly the kind of national recognition for outstanding research we aspire to," says Peter Anton Perry, chair of the math department. "His ambitious research program is bringing to fruition five years of research in continuum mechanics that he has developed in collaboration with students and colleagues both in mathematics and in chemical and materials engineering."

Thomas Widiger: Re-thinking Personality Disorders
"Either you have it or you don't."

Tom Widiger, a professor in the Department of Psychology at UK, says this is how personality disorders have been traditionally defined, and he's quick to take issue with this "either/or" way of thinking about such maladies.

"The American Psychiatric Association believes that someone with a personality disorder is qualitatively distinct from someone with a normal personality," says Widiger, who began his career here in 1982. He adds that such a characterization is based on the analogy of a medical disorder—you either have cancer, for example, or you don't. "My major work is arguing that these personality disorders actually represent a maladaptive variant of common personality traits."

The analogy Widiger prefers has to do with intelligence.

"We think of intelligence, as measured by IQ, as a continuum. All of us can be located somewhere along this continuum." Mental retardation, he says, is simply an arbitrary point on this line. "And it follows that people defined as mentally retarded aren't different in kind, only in degree."

Widiger believes that the same is true of those with personality disorders, even the most extreme disorders.

"It's fairly common for people to think of someone like, for instance, Ted Bundy as a totally alien creature," he says. "The press called him 'a monster,' and though it might make us feel better to think this is somehow true, the fact is that he wasn't different—in kind—from us at all. Many of the genes that provided his pathologic dispositions are present in the general population." Bundy, who was convicted of three murders and died in the electric chair in 1989, was suspected of at least 25 abductions and murders of young women. "It's not that everybody has the potential to be a Ted Bundy, not at all," Widiger quickly points out. "But what made Ted Bundy what he was is the same thing that made your personality." A growing number of psychologists and psychiatrists are coming to believe in this idea of seeing this as a continuum, he says.

In his work on personality disorders, Widiger uses a theoretical model called the Five-Factor Model (FFM), which describes five broad domains of personality: (1) neuroticism versus emotional stability, (2) extraversion versus introversion, (3) openness to experience versus "closedness" to experience, (4) antagonism versus agreeableness, and (5) conscientiousness versus negligence.

But where did these classifications come from? How can something as complex as personality be so easily categorized?

Widiger explains that in order to develop this taxonomy, he became a sort of geologist.

"Throughout the history of psychology, grand theorists have proposed which personality traits are the most important for describing yourself and other people," says Widiger. "My model involved just going to the dictionary, which can be seen as a sedimentary deposit of the most important observations people have made over thousands of years, and doing a lexical analysis of the language." The relative importance of a trait, he says, is indicated by the number of terms that have been invented to describe the various degrees and nuances of that trait. "The FFM domains and facets were identified precisely on the basis of their importance in describing oneself and others."

Widiger's interest in the diagnosis and classification of mental disorders has attracted the attention of psychologists and clinicians across the country. Recently, he has been asked by the director of the National Institute for Mental Health to be part of a task force for the next version of the Diagnostic and Statistical Manual of Mental Disorders (DSM).

"This comprehensive book, the source for knowledge about mental disorders since 1952, is massively important and necessary," Widiger says. "We have to have common language so we can talk with each other about what constitutes a mental disorder and what doesn't. Every hospital uses it and every government agency uses it."

One facet of Widiger's current research has to do with its application. He is working toward actual, clinical use of his model. With a small cadre of graduate students, Widiger is partnering with about 10 local clinical psychologists who have agreed to apply the Five-Factor Model to describe their patients. "Without the research professorship, which is supporting extensive data collection, funding for clinicians to provide their input, and funding of patients to participate in the study, I couldn't do this work," he says.

"We want to show that clinicians can actually use this model to define in a much more useful and helpful way various personality traits of their patients. I want to have an impact on the practice of clinicians and, in turn, have them impact my research."

The University Research Professorships were established in 1976 to recognize outstanding research achievement. The professorships carry an award of $35,000 to enable professors to devote full time to their research or continue to teach and use the award to support research activities. Since the inception of the award, there have been 89 University Research Professors at UK. Funds for this award are provided by the Office of the Vice President for Research.