114 research outputs found
Complex Power Distribution Network Investigation Using SPICE Based Extraction from First Principle Formulations
The modeling and the analysis of the power distribution networks (PDN) within multi-layer printed circuit board is crucial for the investigation of the performance of PCB systems. Carrying out such analyses in SPICE based tools has the advantage of being faster than the corresponding full-wave modeling and it allows obtaining both frequency and time domain results
Power Integrity Investigation of BGA Footprints by Means of the Segmentation Method
The engineering of the power delivery network is becoming a fundamental issue in the design of high speed digital systems on PCB\u27s. In fact, providing the required power to the different IC\u27s at the specified noisefree voltage levels allows a correct functioning of the overall PCB systems. More over, the ongoing trend of replacing active devices with peripherally located I/O and PWR/GND pins with areally located I/O and PWR/GND pins (BGA packaged) increases the complexity of the models, when power delivery issues need to be studied in a larger contest, such as the overall PCB\u27s. The employment of the powerful, but simple, concept of the segmentation method allows investigation of the power delivery network of the PCB systems in two fundamental stages. During the first stage, a small cut out of the board corresponding to the BGA footprint is modelled with a 3D full wave simulation tool. During the second stage the equivalent impedance network representation corresponding to this cut out is combined, by means of the segmentation method [1-5], with larger pieces of a board, whose network representations can be extracted from the closed form expression of the cavity model approach [6-9]
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Compliance to Bleach Disinfection Protocols among Injecting Drug Users in Miami
Bleach cleansing of injection equipment has been recommended to reduce the risk of human immunodeficiency virus (HIV) transmission associated with the reuse of injection equipment by injecting drug users (IDUs). We evaluated the recall and performance of the most commonly recommended bleach cleansing procedure of two complete fillings of the syringe with bleach, followed by two complete fillings with rinse water, and not putting used bleach and water back into source containers. IDUs were taught this procedure on enrollment in an HIV prevention demonstration project in Dade County, Florida. During follow-up session 6-12 months after initial training, the knowledge and ability of IDUs to perform bleach cleansing were assessed by trained observers using a standardized method. In 1988-90, we assessed the knowledge and ability of 450 IDUs to perform the bleach cleansing procedure taught at enrollment. More than 90% of IDUs assessed performed the basic steps. However, only 43.1% completely filled the syringe with bleach and only 35.8% completely filled the syringe with bleach at least twice. Substantial proportions of IDUs did not perform all the steps of the previously taught bleach cleansing procedure. Compliance decreased as the number of steps required was increased. This limited compliance may make bleach cleansing less effective and suggests that some IDUs may fail to adequately disinfect injection equipment and therefore sterile needles and syringes are safer than bleach-cleansed ones. Compliance testing can help assess the effectiveness of HIV prevention programs. © 1994 Raven Press, Ltd., New York
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Summer 1970
The U.S. Nitrogen Industry by George C. Sweeney, Jr. (page 3) Learn the Oil Alphabet by Melvin E. Long (7) Weed Control with Repeated Applications of Tordon Herbicides by John W. Gibson (9) Plants Speed Formation of Soil by Brij L. Sawney (12) St. Augustine Decline (SAD) A Virus Disease of St. Augustine Grass by Norman L. McCoy, Robert W. Toler, and Jose Amador (15) The Problem of Responsibility for Recreation by Ronald F. Paige (19) Editorial (20) Massachusetts Fine Turf Conference (23) Dickinson Memorial Fund (23
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