Buscar
Mostrando ítems 2051-2060 de 5343
Dinámica del nitrógeno en el sistema agroforestal Coffea arabica con Eucalyptus deglupta en la Zona Sur de Costa Rica
(CATIE, Turrialba (Costa Rica), 2004)
En un Ultisol en la Zona Sur de Costa Rica (600 msnm y 2700 mm año exponente -1), en cafetales (Coffea arabica) a pleno soy y café bajo sombra de Eucalyptus deglupta, se evaluaron las tasas de mineralización y nutrificación ...
Impact of the Desilication Treatment of Y Zeolite on the Catalytic Cracking of Bulky Hydrocarbon Molecules
(Springer/Plenum Publishers, 2015-08)
Mesoporosity was induced on a USY zeolite by means of an alkaline leaching process. Samples were immersed in 0.05, 0.10 and 0.20 M NaOH solutions during 15 min at room temperature and then were exchanged with NH4+ ions and ...
Trivalent chromium ion removal from aqueous solutions using low-cost zeolitic materials obtained from exhausted FCC catalysts
(Sage Publications, 2011-07)
The hydrothermal treatment of exhausted FCC catalysts with zeolite was optimized by varying the chemical composition of the synthesis mixture. The zeolitic products obtained were used to evaluate their ability for the ...
Characterization of the Atrazine Sorption Process on Andisol and Ultisol Volcanic Ash-Derived Soils: Kinetic Parameters and the Contribution of Humic Fractions
(2013)
Atrazine sorption was studied in six Andisol and Ultisol soils. Humic and fulvic acids and humin contributions
were established. Sorption on soils was well described by the Freundlich model. Kf values ranged from 2.2−15.6 ...
Formation of hydrocarbon gaseous compounds during bioleaching of copper sulphide minerals with mesophilic microorganisms
(ELSEVIER, 2008-11)
An experimental study was conducted for assessing the formation of hydrocarbon gaseous compounds during bioleaching of copper sulphide ores with mesophilic microorganisms. Three different mineral samples were used: a pyrite ...
Screening and determination of pesticides in soil using continuous subcritical water extraction and gas chromatography - mass spectrometry
(ELSEVIER SCIENCE BV, 2003-04-25)
In the present work the efficiency of water under subcritical conditions for the extraction of pesticides having a broad spectrum of polarities from soils was evaluated. The pesticides under study were carbofuran, ...
Ultrasound-assisted pressurized solvent extraction for aliphatic and polycyclic aromatic hydrocarbons from soils
(ELSEVIER, 2006-11-03)
In the present work the efficiency of extraction of aliphatic diesel range organics (DROs) and polycyclic aromatic hydrocarbons (PAHs) from soil was assessed by using dynamic modes of pressurized solvent extraction (PSE), ...
Avaliação das técnicas de precipitação química e encapsulamento no tratamento e destinação conjunta de resíduos líquidos contendo cromo e vidrarias de laboratório
(Sociedade Brasileira de Química, 2008)
In this paper, we present procedures for the treatment and final disposal of residual solutions containing chromium, in order to evaluate the effectiveness of chemical precipitation of the metal and the potential of the ...
Effect of accelerated carbonation on cementitious roofing tiles reinforced with lignocellulosic fibre
(ELSEVIER SCI LTD, 2010)
The present work evaluated the effects of accelerated carbonation on mechanical and physical characteristics of cementitious roofing tiles reinforced with vegetable fibre. The maximum load and toughness of the tiles have ...
A study of the chemical and physical properties of cashew nut shell ash for use in cement materials.
(UNIV ESTADUAL MARINGA, PRO-REITORIA PESQUISA POS-GRADUACAO, 2010)
A study of the chemical and physical properties of cashew nut shell ash for use in cement materials. Ash occupies a prominent place among agro-industrial wastes, as it is derived from energy generation processes. Several ...