Spine injuries in combat troops--Panama, 1989

Operation Just Cause was until recently the largest American combat operation since Vietnam, and remains the largest nighttime parachute operation since World War II. All 252 casualties were airlifted to San Antonio, Texas, for medical treatment. Greater than 80% sustained orthopedic injuries. Sixteen patients were admitted for injuries to the back or neck. Three of the four patients with significant fractures or fracture-dislocations were paraplegic. Two of the three patients with gunshot wounds to the back required extensive reconstruction for wound management. In addition to the 252 casualties, there were 23 fatalities, among whom 7 suffered major injuries to the spine. Spine injuries represented the most significant source of long-term morbidity among those soldiers wounded in combat in Panama, and were common among the fatalities. Noteworthy in these cases was the high percentage of severe neurologic injuries in patients with significant fractures (75%), particularly fractures associated with gunshot wounds. Also of interest were the cases of major soft tissue injury associated with high-velocity gunshot wounds (66%) and the extensive soft tissue surgery needed to treat these injuries.     

Acceptance sampling: an efficient, accurate method for estimatingand optimizing parametric yield [IC manufacture]

Acceptance sampling is a new yield estimation and optimization method which combines the accuracy of Monte Carlo analysis with the computational efficiency of response surface methods. Response surface approximations are used to guide selection of simulation samples. Formulas based on established statistical methods (viz., confidence intervals, stratified sampling) estimate yield and predict accuracy. Yield optimization procedures employ conventional search algorithms. Examples using 50 to 100 simulations demonstrate accuracy matching 1000 to 10000 Monte Carlo samples     

Consecutive k-out-of-n:F system with sequential failures and a single repair

This paper presents a solution for determining the mean time to system failure of a consecutive k-out-of-n:F system with a single repair. The components of the system are subject to sequential failures. The mean time to system failure is evaluated by making use of the relation between the reliability function and the probability of the first passage time to system failure. The Laplace transform of the first passage time to system failure is obtained as a ratio of two determinants.     

Switched-capacitor neuromorphs with wide-range variable dynamics.

The use of switched capacitors as wide-range, programmable resistive elements in spatially extensive artificial dendritic trees (ADT's) is described. We show that silicon neuro-morphs with ADT's can produce impulse responses that last millions of times longer than the initiating impulse and that dynamical responses are tunable in both shape and duration over a wide range. The switched-capacitor resistors forming a dendritic tree are shown indirectly to have a useful programmable resistance range between 500 KOmega and 1000 GOmega. Experimental results are presented that show variable impulse response functions, tunable frequency selectivity, and rate-invariance of spatiotemporal pattern responses.     

A comparison of energy consumption in eastern and western Europe

The aim of this paper is to examine the factors affecting energy consumption in eastern Europe and also to make a comparison with western Europe. The authors first examine 1978 energy consumption figures and energy intensities for the two regions. Then, to give a clearer picture of long-term developments, a dynamic analysis for the period 1950–1975 is presented. Finally, on the basis of both comparisons, an attempt is made to illustrate the results macroeconomically. The higher energy intensity in eastern European countries cannot be explained in terms of any one factor. Any explanation should include economic conditions, climate and energy supplies.     

Railroad track modulus estimation using ground penetrating radar measurements

Track defects and failures resulting from weak strength and buckling cause many of the railroad accidents. One parameter that greatly affects track performance and safety is the track vertical modulus, which is a measure of the vertical stiffness of the rail foundation. Current techniques for track modulus measurement, while accurate, are time-consuming, labor-intensive, require track closure, and provide only single-point information. Ground penetrating radar (GPR) is a non-destructive and non-invasive technology that has shows great potential for imaging subsurface features and assessing the integrity of track substructure. The technique is based on the principles of electromagnetic wave reflection from and transmission through distinct layers of varying dielectric properties. A single electromagnetic pulse of energy at an appropriate frequency is launched into the ground, and reflections from various subsurface layers are recorded in the form of an image. Since studies have shown that the electrical properties of base course aggregates can be used to infer their strength properties, we hypothesize that the information on the track substructure layering characteristics can be used to indirectly infer track modulus. Using a comprehensive set of coincident GPR and track modulus measurements acquired over various types of railroad track geometries, a multivariate linear regression model has been developed. Our analysis reveals a consistent relationship between the weighted average of subsurface 400 MHz GPR reflectivities at specific depths to the measured track modulus with an accuracy of better than approximately 3.4 MPa (500 lb/in./in.). The model is thus able to predict track modulus from GPR measurements, and would considerably reduce the time and expense of operational track maintenance strategies.