3125227 documents found, page 8433 of 312523
Influência do contra-íon molibdênio nas propriedades do pigmento SnO2: Cr
Silva, Renata Ferreira Lins daSnO2 pigments, when doped with chromium, lead to violet or purple colors, depending on chromium oxidation state. There is a need to control the chromophore oxidation state, as Cr(VI) is toxic and carcinogenic, while Cr(III) leads to no risk to living beings. Cr(VI) formation may be avoided with the addition of counterions, that lead to a charge imbalance. In this work, SnO2:Cr pigments were synthesized by the p...
Determinação da acidez total de vinhos tintos empregando titulações baseadas em...
Tôrres, Adamastor RodriguesThis work proposes the use of digital images captured by a Webcam for determination of total acidity in red wines by means of an acid-base titration without using an external indicator. Digital images present the colour of the emergent radiation, which is complementary to the radiation absorbed by molecules of anthocyanines presents in wines. Each image, generated according to RGB system, yields a matrix of the...
Novas Perspectivas da Glicerina Síntese de Novos Nitratos com Propriedades Farm...
Santos, Alexsandro Fernandes dosThe major purposes for the production and use of biodiesels are environmental, social and economic benefits. However the production of 90 cubic meters of biodiesel generates about 10 cubic meters of glycerin, so partial or total replacement of diesel by biodiesel can because of glycerin generate a lot of problems. A great surplus (without market), could force the devaluation of its price, and glycerin factories...
Estudos químicos e avaliação antioxidante, bactericida e larvicida do óleo esse...
Sousa, Manaces CunhaThis study aimed to investigate major metabolites from the aerial parts of Ocimum basilicum by a phytochemical screening. Quantitatively extracting the essential oil and subjecting it to thermal analysis and chromatography, as well as verifying its performance as an antioxidant, antibacterial and larvicidal agents. In this study it was observed that the aerial parts of Ocimum basilicum present tannins, depsides...
Microfabricação de um analisador em Fluxo-Batelada (Micro Flow-Batch) à base de...
Monte Filho, Severino Sílvio doThis work describes the construction of a new flow-batch analyzer (FB) in micro scale (micro Flow-Batch-μFBA) using the technique of deep ultraviolet photolithography with commercial resin based in urethane acrylate oligomers (UA). The device was constructed from the union of two layers of pre-polymerized resin of 3.4 mm thick each, thus forming a single structure. The main feature of the new device is the smal...
Vermiculitas tratadas quimicamente na obtenção de sólidos microporosos como pre...
Alves, Ana Paula de MeloThe selective leaching of clay minerals is an important method in the preparation of porous silicates presenting as a simple, effective and low cost route. In this study, vermiculite was submitted to acid treatment at concentrations 1, 2, 3, and 4 mol dm-3, resulting the precursor solids named as VacX (x=1 a 4), respectively. The lixiviated matrices and vermiculite reacted covalently with the organosilanes amin...
Caracterização, estabilidade oxidativa e determinação do potencial energético d...
Melo, Maria Ladjane Sodré deThe aim of this research was to study the chemical and physical properties of the papaya seeds of three different cultivars produced in Brazil: Sunrise Solo (Hawaii), Golden and Formosa. The chemical composition of the seeds and the extracted oils, physical chemical properties of oils and obtained biodiesel were analyzed to evaluate the industrial use of this disposable residue as renewable energy source. Golde...
Cardanol e Eugenol Modificados - Uso como antioxidante no controle do processo ...
Rodrigues Filho, Manoel GabrielBiodiesel is composed by a mixture of different kinds of esters that may have unsaturations in their chains. These unsaturations are susceptible to oxidation processes, especially in the presence of oxygen. The oxidative stability of biodiesel becomes therefore an important quality parameter since the oxidation of the esters may cause some problems when using this fuel. In the search for new technologies to sol...
Blendas de biodiesel: propriedades de fluxo, estabilidade térmica e oxidativa e...
Dantas, Manoel BarbosaThe Brazilian biodiesel, whatever the source of their raw materials must meet some physical and chemical parameters that ensure their quality. A major problem associated with the use of biodiesel, especially prepared with castor oil, is its high viscosity that is outside the limit set by the ANP, becoming viable as fuel, only when used as a blend to diesel or other biodiesel with lower viscosity. The soybean bi...
Monitoramento da Estabilidade Oxidativa no Armazenamento de Biodiesel Metílico ...
Melo, Marco Aurelio Rodrigues deThe present paper aimed at synthesizing, storing and monitoring biodiesel from the alkaline homogeneous transesterification of soybean oil and castor oil, using the methanol route, as well as evaluating the oxidative stability, during a 60 day-period, by means of the EN14112 standard. Blends of castor oil biodiesel and soybean oil biodiesel, containing 10, 20 and 30% v/v of castor oil biodiesel, respectively ca...