Global Power Technologies Group (United States)

Carole B. Lewis, PT, DPT, GTC, PhD, has focused throughout her career on the continuous improvement of clinical care provided to older adults. Dr Lewis is an adjunct professor at the George Washington University Medical Center Department of Health Care Services and continues to work in private practice. She serves as president of Great Seminars and Books and Great Seminars Online and for 33 years has been editor-in-chief of Topics in Geriatric Rehabilitation , which won the Association of American Publishers' Award for the Most Outstanding Issue of a Scientific Journal. She earned a DPT from MGH Institute of Health Professions, a PhD in health education from the University of Maryland, an MS in gerontology from the University of Southern California Leonard Davis School, an MPA in health care management from the University of Southern California, and a BS in physical therapy from The Ohio State University. Dr Lewis has held 24 consultation positions in clinics and workplaces and with third-party payers. One of the first researchers to determine that older adults are able to exercise safely and can realize major improvements in outcomes when prescribed appropriate exercise, Dr Lewis has published extensively in the field of aging, with research published in journals such as Archives of Physical Medicine and Rehabilitation and the New England Journal of Medicine. She is author of more than 20 textbooks on aging, including what may be the first text on aging and rehabilitation and one of the first on functional assessment ( Aging: Health Care's Challenge: Interdisciplinary Assessment and Treatment of the Geriatric Patient , now in its fourth edition; Geriatric Clinical Strategies ; Geriatric Physical Therapy ; Orthopedic Assessment and Treatment of the Geriatric Patient ; The Geriatric Exercise Kit ; The Functional Toolbox I & II ; The Balance Book and Osteoporosis Exercise …

A well designed Silicon Carbide (SiC) Schottky-Barrier Diode (SBD) has to optimize reverse leakage current in addition to the familiar silicon (Si) device trade-off of avalanche breakdown voltage (BV) and forward voltage drop (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">F</sub> ). Reverse leakage current is a strong function of temperature and we show experimentally that this sensitivity of reverse leakage to temperature is a function of the electric field at the Schottky interface at rated voltage. We model this phenomenon using Hatakeyama's approximations of electron emission across the metal-SiC barrier. This model and our results point to a previously un-reported design trade-off between BV margin over rated voltage and temperature dependence of SiC SBD rated reverse leakage current. Using this trade-off, we show that optimum epitaxial design of a SiC SBD is different for a given rated voltage than what mere BV vs R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">on</sub> considerations indicate. Optimized epitaxy is also different for different JBS geometries.

In this paper, a hybrid booster power module with Si IGBT and Silicon Carbide (SiC) Schottky Barrier Diode (SBDs) is presented. The switching characteristics of the hybrid booster module are compared with commercial Silicon IGBT/Si PIN diode based modules. We applied the booster power module into a non-isolated on board vehicle charger with a simple buck-booster topology. The performances of the on-vehicle charger are analyzed and measured with different power modules. The test data is measured in the same system, at the same points of operation, using the conventional Si and hybrid Si/SiC power modules. The measured power conversion efficiency of the proposed on-vehicle charger is 96.4 % with the SiC SBD based hybrid booster module. The conversion efficiency gain of 1.4 % is realizable by replacing the Si-based booster module with the Si IGBT/SiC SBD hybrid boost module in the 6.6 kW on-vehicle chargers.

Abstract Records obtained in a 2-year period (1960 and 1961) in hilly terrain in the unglaciated section of southwestern Wisconsin near La Crosse showed that the springtime frost frequency between April 26 and July 1 was about twice as high in a cove at 920 feet elevation as on a nearby ridgetop at 1,250 feet elevation. Freezes of 30° F. or less occured three times as often in the cove. The degree-hours of frost of 30° F. or less in the period were eight times as abundant in the cove as on the ridgetop. For freezes of 28° F. or less, the cove had 67.5 degree-hours compared to none on the ridgetop. In the cove, temperatures reached minima of 1.0 to 10.5° F. colder than on the ridge in eight of nine times on which freezes occurred in this period; these minima on six occasions were at least 3° F. colder for the cove. The temperature inversions were greatest on calm, clear nights. Long-term records over an 89-year period at La Crosse indicate there is probability of a freezing temperature on the average of about once every 2½ years in May.