Research Digest | Search | MIT News | Comments | MIT
These brief summaries of MIT research are drawn
from several sources and are issued throughout the year. More
information on any of these stories can be obtained by
contacting
the MIT News Office. In some
cases, photos may be available for news organizations.
|
Front (left) and back views of a new
microchip for the controlled release of chemicals. The dots
between the three large bars (cathodes) on the front are the
caps (anodes) covering the reservoirs that hold chemicals.
An electrical voltage applied between a reservoir cap and a
cathode causes a reaction that dissolves the cap, releasing
the chemical. The back view shows the larger openings for
each reservoir through which chemicals are deposited.
Photo by Paul Horwitz, Atlantic Photo Service, Inc.
|
Coal-Mining Productivity. Coal plays an important role in our national well-being: it provides more than a fifth of the energy and half of the electricity consumed in the United States. Much attention therefore focuses on coal-mining productivity. National statistics to that end show that -- except during the 1970s -- coal mines have become steadily more efficient. However, an MIT Energy Laboratory study by Sloan School lecturer A. Denny Ellerman, director of MIT's Center for Energy and Environmental Policy Research (CEEPR), and Economics Professors Thomas Stoker and Ernst Berndt suggests that those national statistics do not tell the whole story. Their analysis of productivity data for more than 19,000 mines from 1972-1995 showed that some regions and technologies lagged far behind others. Further analyses of why productivity changed brought some unexpected results. For example, even after accounting for geology and technology, bigger mines were more productive than smaller ones. The study shows that aggregated national productivity data do not provide an accurate picture of the efficiency with which an industry uses its resources or of the causes of changes in overall productivity. CEEPR supported the research.
Diet Drug & Blood Chemistry. Even a single, low dose of the diet drug phentermine inhibits an important enzyme in the blood, according to a January 2 paper in the journal Lancet by researchers at the Massachusetts College of Pharmacy and Allied Health Sciences (MCP/AHS) and MIT. From 1992 to 1997, millions of Americans were prescribed "fen-phen," which includes the amphetamine-like phentermine, for weight control. A small number of people who took the anti-obesity drug combination developed primary pulmonary hypertension and heart valve lesions, which may be tied to the effect phentermine has on blood chemistry in combination with fenfluramine, the other half of the weight-loss drug duo. The Lancet authors are MCP professor Timothy Maher (also a lecturer in MIT's Department of Brain and Cognitive Sciences, or BCS); visiting MIT scientist Ismail Ulus, a professor at the University of Uludag in Turkey; and BCS Professor Richard Wurtman, director of MIT's Clinical Research Center. The trio also reported these findings in September 1998 at the International Congress of Obesity in Paris. These studies were supported in part by the NIH and the Center for Brain Sciences & Metabolism Charitable Trust.
The Age Lab. Global aging -- with its social, political and economic consequences -- is a growing concern for scientists and citizens alike. Enter MIT's Age Lab, a new initiative through the Center for Transportation Studies. Headed by Dr. Joseph Coughlin, the Age Lab is working with the business and medical communities to help people over 60 live healthy, independent lives. For example, driving is a crucial part of independent aging. But aging diminishes physical and mental capabilities needed for safe driving. The Age Lab aims to exploit new technologies for a next-generation transportation system for elders, including intelligent vehicle applications to compensate for diminished physical capabilities. Coughlin also notes that seniors are more likely to die from falls at home. So the Age Lab is examining new safety and health standards and information technology products for the home and establishing a model safe-home environment for demonstration purposes in homes and care facilities. In addition to engineering, human-factors and marketing researchers, two medical doctors are affiliated with the lab. One is working on issues surrounding the vision of older adults, the other is a geriatrician concerned with overall health needs. The lab is funded primarily by industry -- including EDS and St. Jude Medical, Inc. -- as well as by the American Association of Retired Persons and private foundations.
New "Active" Materials. Apply an electrical voltage to certain materials, and they will stretch, shrink, or otherwise give a mechanical response. Known as piezoelectrics, such materials are currently used in a variety of devices such as autofocus cameras, high-precision positioners for atomic-force microscopes, and vibration dampeners in high-performance skis. The piezoelectrics with the best properties, however, contain lead oxide. The toxicity of this compound has led to an increasing demand for alternative materials that are environmentally benign. Now MIT researchers led by Professor Yet-Ming Chiang in the Department of Materials Science and Engineering have identified just such a family of materials. As they reported in a recent issue of Applied Physics Letters, the new lead-free piezoelectrics not only exhibit an exceptionally high piezoelectric response, but can also easily be grown as single crystals. (Piezoelectric materials made of single crystals have higher performance than those made of multiple crystals.) The MIT work has also shown that continuous single-crystal piezoelectric fibers can be grown, paving the way for development of "active fiber composites" whose mechanical response is electronically controlled. The work is supported by the ONR and the Army Research Office-Multidisciplinary University Research Initiative.
When Stars Die. When massive stars die, they may leave behind objects that are more unusual and exotic than previously imagined, says MIT Professor Victoria Kaspi of physics and the Center for Space Research. For one thing, the pulsar -- a type of neutron star that has long been thought to be the standard product of such stellar deaths -- may be merely one species in a larger zoo. At an invited talk at the annual meeting of the American Astronomical Society, Kaspi noted alternatives to pulsars such as unusual celestial X-ray sources called anomalous X-ray pulsars, unpredictable soft gamma-ray repeaters, and magnetars, ultra-magnetized neutron stars hypothesized to explain these phenomena. Also in the family may be quiet, isolated, cooling neutron stars that, for unknown reasons, never "turned on" to radiate like their cousins. By taking a broad look at diverse types of recent observations, Kaspi and others are starting to unify these observations into one cohesive explanation of what happens when a massive star dies. This work is funded primarily by NASA.
