Simón Bolívar University

About: Simón Bolívar University is a education organization based out in Caracas, Venezuela. It is known for research contribution in the topics: Population & Crystallization. The organization has 5912 authors who have published 8294 publications receiving 126152 citations.

Direct extraction of semiconductor device parameters using lateral optimization method

Abstract: Direct extraction of semiconductor device parameters using lateral optimization method A. Ortiz-Conde, Yuansheng Ma, J. Thomson, E. Santos, J.J. Liou*, F.J. Garco a Sa nchez, M. Lei, J. Finol, P. Layman Departamento de ElectroÂnica, Universidad SimoÂn BoloÂvar, Apartado 89000, Caracas, 1080-A, Venezuela Department of ECE, University of Central Florida, Orlando, FL 32816-2450, USA Modeling and Simulation Group, Lucent Technologies, Orlando, FL, USA Motorola, 3102 North 56th Street, Phoenix, Arizona 85018, USA

Fire intensity and severity in brazilian campos grasslands

Abstract: SUMMARY Brazilian Campos grasslands are rich in species and the maintenance of its diversity and physiognomy is dependent on disturbance (e.g. fire and grazing). Nevertheless, studies about fire intensity and severity are inexistent. The present paper describes fire parameters, using 14 experimental burn plots in southern Brazil (30o02’ to 30o04’S, and 51o06’ to 51o09’W, 311masl). Two sites under different fire histories were chosen: frequent ly burned and excluded since six years. Experimental burning was performed during summer (2006-2007), when most burning takes place in these grasslands. The following parameters were measured: air temperature and moisture, vegetation height, wind speed, fuel (fine, coarse), fuel moisture, fire temperatures (soil level and at 50cm), ash, residuals, flame height, fire dura tion; burning efficiency and fire intensity were later calculated. Fuel load varied from 0.39 to 1.44kg·m -2 , and correlated positively with both fire temperature and fire intensity. Fire tempera tures ranged 47 to 537.5°C, being higher in the excluded site. Fire intensity was low compared to grassland elsewhere (36.5319.5kW·m -1 ), differing significantly between sites. Fine fuel was the variable that best explained fire intensity. The results on fire intensity and severity in Campos grasslands can be considered a pilot study, since plots were very small. However, the data provided can help other researchers to get permission for experimentation using larger plots. The results provide support for further studies about the effects of fire on grassland vegetation and for studies involving fire models and fire risk prediction.