Zobrazeno 1 - 10
of 40
pro vyhledávání: '"Valnei S. Cunha"'
Autor:
Mary A. Gonçalves, Fabiano B. Gonzaga, Isabel C. S. Fraga, Carla M. Ribeiro, Sidney P. Sobral, Eliane C. P. Rego, Elaine B. Santana, Leonardo M. Oliveira, Viviane F. Silva, Rodrigo V. P. Leal, Dalni M. E. Santo Filho, José R. R. Siqueira, Thales P. Barbosa, Janaína M. Rodrigues, Valnei S. Cunha, Vinícius L. Skrobot, Cristiane B. Costa, Aderson R. Pessoa Júnior, Helena S. P. Carneiro, Helenice Colares, Ednéia Caliman, Márcia V. S. Alves
Publikováno v:
Química Nova, Vol 36, Iss 3, Pp 393-399 (2013)
This work shows the results of a Proficiency Testing performed by a partnership between INMETRO and ANP. The performance of 49 Brazilian laboratories (using the z-score statistical test) in determining 10 quality parameters of ethanol fuel and biodie
Externí odkaz:
https://doaj.org/article/7b8171c17fff4447b68c2e81ef17eba6
Autor:
Janaína M. Rodrigues, Evelyn F. Guimarães, Marcus V. B. Sousa, Viviane F. Silva, Isabel C. S. Fraga, Vanderléa Souza, Valnei S. Cunha
Publikováno v:
Química Nova, Vol 35, Iss 5, Pp 1011-1015 (2012)
Bioethanol is a strategic biofuel in Brazil. Thus, a strong metrological basis for its measurements is required to ensure the quality and promote its exportation. Recently, Inmetro certified a reference material for water content in bioethanol. This
Externí odkaz:
https://doaj.org/article/5f2cf0fb0d294f6c8b44b7f0029eb9fd
Autor:
Raquel D. C. C. Bandeira, Thais M. Uekane, Carolina P. da Cunha, Luths R. O. Geaquinto, Valnei S. Cunha, Janaina M. R. Caixeiro, Ronoel Luiz O. Godoy, Marcus Henrique C. de la Cruz
Publikováno v:
Química Nova, Vol 35, Iss 1, Pp 66-71 (2012)
A method using LC/ESI-MS/MS for the quantitative analysis of Ochratoxin A in roasted coffee was described. Linearity was demonstrated (r = 0.9175). The limits of detection and quantification were 1.0 and 3.0 ng g-1, respectively. Trueness, repeatabil
Externí odkaz:
https://doaj.org/article/9df1bf28f0044882982375fb52af58c7
Publikováno v:
Research & Development in Material Science. 10
Publikováno v:
Waste and Biomass Valorization. 8:1265-1271
This paper describes the preparation of a biobased catalyst derived from residual Jatropha curcas cake using a combination of low-temperature conversion and chemical treatment to be applied for epoxidation of vegetable oil. The catalyst was character
Autor:
Samantha R. Silva, A. S. Sarpal, Thays V. C. Monteiro, Júlia Itacolomy, Paulo R. M. Silva, Valnei S. Cunha, Romeu J. Daroda
Publikováno v:
Energy & Fuels. 29:7956-7968
A direct, rapid, and convenient method for the determination of iodine value (IV) of biodiesels from vegetable oils has been developed by the application of nuclear magnetic resonance (500 and 600 MHz 1H NMR) techniques. The method is based on the co
Autor:
Luiz Roberto Barbosa Morais, Thays V. C. Monteiro, Alessandra Sussulini, Werickson Fortunato de Carvalho Rocha, Marcos N. Eberlin, Maíra Fasciotti, Valnei S. Cunha
Publikováno v:
European Journal of Lipid Science and Technology. 122:2000019
Autor:
Luciano N. Batista, Claudia S. C. Castro, Valnei S. Cunha, Marcos A. S. Costa, Viviane Fernandes da Silva, Eveline De Robertis
Publikováno v:
Journal of Thermal Analysis and Calorimetry. 123:973-980
Metal cutting fluids (MCFs) or cutting fluids are widely applied industrial products traditionally based on hydrocarbons. However, hydrocarbon-based cutting fluids have low thermal stability and tend to vaporize during application, causing environmen
Autor:
Marcos N. Eberlin, Ildenize B. S. Cunha, Paulo Rogério Catarini da Silva, Soraya El-Khatib, Anna Maria A. P. Fernandes, Rosana M. Alberici, Márcio José da Silva, Andreia M Porcari, Romeu J. Daroda, Valnei S. Cunha
Publikováno v:
Energy & Fuels. 29:3096-3103
Biodiesel has become increasingly attractive because of its environmental benefits and production from renewable resources. The use of Jatropha curcas L. oil as the feedstock for biodiesel production has attracted growing interest because it is a non
Autor:
Gilberto F. de Sá, Marcos N. Eberlin, Romeu J. Daroda, Giovana A. Bataglion, Nelson H. Morgon, Renan Galaverna, Gabriel Heerdt, Valnei S. Cunha
Publikováno v:
European Journal of Organic Chemistry. 2015:2189-2196
To address the title question, the relative intrinsic acidities of phenol and benzoic acid as well as the isomeric family of ortho-, meta-, and para-hydroxybenzoic acids were compared. Dissociation of the [PhCO2···H···OPh]– proton-bound dimer