RESUMO
Brazil is the largest worldwide producer of alcohol and sugar from sugar-cane and has an extensive alternative program for car fuel which is unique. The objective of this work is to offer one management option of a solid residue produced by this industrial segment. The pressed sugar-cane bagasse is burned to produce steam and electricity by cogeneration. The combustion yields both bottom and fly ashes which contain high amounts of silicon oxide as a major component. Fly ash which contains a high volume (>30% by weight) of charcoal was used in this work. The ash was sieved to separate the thick charcoal from inorganic materials which are concentrated in the thinner fraction. The briquettes were hand pressed using charcoal mixed with a binder (starch) obtained from cassava flour (a tropical root). The results (density, mechanical resistance) obtained with 8% by weight of starch binder are presented here. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) were used to characterize the ashes and the briquettes. The results show that sugar-cane bagasse fly ash (SCBFA) can be used to produce briquettes with an average density of 1.12gcm(-3) and an average calorific value of 25,551kJ/kg.
Assuntos
Biocombustíveis , Carbono/química , Celulose/química , Carvão Vegetal/síntese química , Material Particulado/química , Brasil , Varredura Diferencial de Calorimetria , Carvão Vegetal/química , Cinza de Carvão , TermogravimetriaRESUMO
Avaliou-se o efeito da dexametasona, a 0,1%, sobre a pressäo intra-ocular de 48 olhos de 46 pacientes portadores de glaucoma crônico simples, cuja pressäo intra-ocular foi controlada cirurgicamente há mais de seis meses, e que näo faziam uso de nenhuma medicaçäo hipotensora adicional. Os pacientes foram divididos conforme a técnica cirúrgica adotada: Grupo I, 18 pacientes operados de Trabeculectomia, Grupo II, 13 pacientes operados de Iridencleise, e Grupo III, 15 pacientes submetidos a trepanaçäo córneo-escleral de Elliot. Todos os pacientes dos 3 grupos, näo apresentaram variaçäo da pressäo intra-ocular significativa ao teste da dexametasona
Assuntos
Humanos , Feminino , Masculino , Adulto , Dexametasona/administração & dosagem , Glaucoma de Ângulo Aberto/cirurgia , Pressão Intraocular/efeitos dos fármacos , BrasilRESUMO
We have determined the genotoxic and mutagenic activities associated with inhalable particulate matter (IPM) collected in Rio de Janeiro, Brazil, Camden, NJ, and Caldecott Tunnel, CA, and used these results to compare three different bioassays. Samples collected every 12 hr (Rio) or every 24 hr (Camden) were extracted sequentially with cyclohexane (CX), dichloromethane (DCM), and acetone (ACE), for a rough fractionation by polarity, and composites of the extracts were tested for mutagenicity using the Salmonella frame shift (TA98) and base substitution (TA100) tester strains, as well as for genotoxicity using the Rossman Microscreen bioassay based on the induction of lambda-prophage in a lysogenic Escherichia coli strain. All samples were tested without and with S9 metabolic activation. Maximum mutagenic and genotoxic activities were in the nonpolar (CX) and polar (ACE) fractions, respectively, indicating that these two assays detect different classes of compounds with different efficiencies. Oxidative aging of the Rio aerosol is indicated by a shift in activities in both tests from the less polar fractions in the day to the polar (ACE) fraction at night. The Rio TA98 mutagenic (18 rev/m3) and genotoxic (1.4 x 10(5) PFU/m3) activities were higher than those for Camden, an Eastern U.S. city, by factors of 1.4 and 2.8, respectively.