Catalisador Pd/gama-Al2O3: efeito do tamanho de partícula na atividade catalítica para combustão do CH4

Methane, the main constituent of natural gas (> 85%), is employed in large scale as an energy source (thermoelectric power plants, automobiles, etc). However, significant quantities of this gas contribute to the greenhouse effect. The catalytic combustion of methane can minimize these emissions. Palladium is one of the metals that shows the highest activity, depending on the different active forms of the metal. In this article, we focus on the influence of particle size and pretreatment on the catalytic performance of palladium in the methane combustion reaction.

Titulação potenciométrica aplicada na determinação de ácidos graxos livres de óleos e gorduras comestíveis

Free fatty acids are a measure of evaluating fats and oils, submitted to abusive conditions, besides being a quality characteristic of edible vegetable oils. The official method of determination (AOCS Ca 5a-40, 2004) is based on titration, using phenolphthalein as an indicator. For crude and degummed oils, the titration end point is difficult to be observed due to the high level of pigments, resulting in dark solutions. In this case and others, such as self-life studies, in which sample quantities are limited, potentiometric titration may be a very good alternative.

A technique for high recoveries from vacuum distillations

The design and use of a novel apparatus for a variant of vacuum distillation is described. Relative to a conventional device, the apparatus/technique described permits superior recovery of multigram quantities of moderately volatile liquids from vacuum distillations.

Projecte de legalització d'una activitat dedicada a l'explotació ramadera i a la formatgeria artesanal

La integració en una mateixa activitat d'una explotació ramadera ecològica basada en el bestiar cabrú de llet i d'una formatgeria artesanal basada en varietats autòctones de formatge de cabra, permet ocupar un nínxol de mercat encara poc explotat actualment a Catalunya. D'igual manera, la dificultat que tenen actualment molts dels formatgers artesans del país per trobar llet de cabra en quantitats suficients i amb unes mínimes garanties higiènico-sanitàries dificulten l'avanç d'un sector amb molt bones perspectives de futur com és el de la formatgeria artesanal i justifica la necessitat de crear noves explotacions (o reconvertir-ne de ja existents) orientant-les de ple vers l'aprofitament lleter del bestiar cabrú, que és actualment molt reduït en l'àmbit Català. A més d'això, les actuals exigències en el camp del benestar animal així com en el camp de la qualitat i de la seguretat alimentaria, exigeixen a les explotacions ramaderes i a les indústries alimentàries el compliment d'una sèrie de requisits, tan de disseny dels locals i de les instal•lacions, com de control de les activitats i dels productes elaborats, que garanteixin en tot moment la seva correcte gestió i funcionament en aquestes matèries. L'objectiu d'aquest projecte, doncs, és la legalització d'una activitat, que anomenarem “Mas Peirot, S.L.”, dedicada a l'explotació ramadera ecològica de bestiar cabrú de llet i a la formatgeria artesanal de formatge de cabra. És important mencionar que tot i tractar-se d'un projecte de legalització d'una activitat,, també s'hi han contemplat aspectes i detalls relacionats amb l'execució de la mateixa, al tractar-se d'unes obres d'una certa complexitat i considerant que així es tracten amb més detall i rigorositat les actuacions projectades. En concret, en aquest projecte es planifiquen les operacions de rehabilitació de dues naus ramaderes actualment en desús, per tal que puguin destinar-se a l'explotació ramadera de bestiar cabrú i a la formatgeria artesanal, projectant-se així mateix totes les instal•lacions necessàries per tal que a les mencionades naus s'hi puguin desenvolupar les activitats citades. Com a conclusions més importants d'aquest projecte podem dir que amb un cens de 100 caps de bestiar cabrú és possible obtenir una producció mitjana de llet de 32.500 litres anuals, que es corresponen a un volum total de 3.823 quilograms de formatge a l'any (de les tipologies Formatge Garrotxa i Formatge de cabra amb oli, ambdues varietats tradicionals catalanes) obtenint un benefici de 21.389,47 Euros/any durant els primers 15 anys i un benefici de 33.386,39 Euros/any a partir del 16è any, cosa que permetrà recuperar la inversió inicial de 172.716,76 Euros que valen les naus i instal•lacions projectades, en un termini de 8 anys i permetrà, com s'ha dit, ocupar un nínxol de mercat encara poc explotat per la indústria agroalimentària a Catalunya.

Caracterização das cinzas de incineração de resíduos industriais e de serviços de saúde

Three ash samples from an incinerator in Belo Horizonte (Brazil) were physically and chemically characterized. The chemical composition of the ashes was not always the same, neither in terms of the chemical species nor in terms of the quantities of those that are common to the three ashes. The ashes called CF1 and CF3D contain heavy metals above the detection limits of the analytical methods and the zinc concentration is high enough to justify treatment of the ashes. For these ashes, a high loss on ignition was found, indicating that the process of incineration might present failures.

Isolation of compounds attractive to the leaf-cutting ant Atta sexdens rubropilosa forel (hymenoptera: Formicidae) from Mabea fistulifera elaiosome

Mabea fistulifera (Euphorbiaceae)is a pioneer plant species with seeds dispersed by the ant Atta sexdens rubropilosa. Since the ants are attracted to the seeds to use its elaiosome as a source of energy, we investigated its composition. The elaiosomes from 13,000 seeds were extracted with a methanol:chloroform mixture (2:1 v/v) and yielded 22% of a residue. This residue was fractionated by column chromatography and its composition determined by infrared spectroscopy and chromatography/mass spectrometry (GC-MS). The elaiosome lipids are constituted mainly by free fatty acids, triacylglycerols and minor quantities of monoacylglycerols or diacylglycerols.

Influência da temperatura de secagem sobre o rendimento e a composição química do óleo essencial de Tanaecium nocturnum (barb. Rodr.) bur. & K. Shum

The yields and chemical compositions of the essential oils obtained by steam distillation of the fresh and dried (30 and 40 ºC) leaves, stems and roots of Tanaecium nocturnum are reported. The identification and quantification of the volatile constituents were accomplished by GC/MS and GC/FID, respectively. The essential oils obtained from the various parts of the plant were constituted mainly of benzaldehyde. Large losses and variations in the quantities of the components during the drying process were observed. The presence of mandelonitrile in higher concentration in the stem and roots indicates that this species produces cyanogenic glycosides.

Sellutehtaan sekundäärilämmön käytön tehostaminen

Energia on olennainen osa nykyaikaisen sellutehtaan prosesseja, joissa kuluu suuria määriä lämpöä ja sähköä. Pyrittäessä entistä kustannustehokkaampaan liiketoimintaan nousee energiatehokkuus usein mielenkiinnon kohteeksi. Pitkälle viety sähkön ja lämmön yhteistuotanto yhdistettynä korkeaan biopolttoaineiden osuuteen energian tuotannossa luovat pohjan tälle pyrkimykselle. Sekundäärilämpöä syntyy prosessien sivutuotteena ja sen mahdollisimman suuri hyödyntäminen on yksi keino päästä kohti parempaa energiatehokkuutta. Joissain tapauksissa sillä voidaan korvata jopa primäärienergian käyttöä ja mahdollisesti pienentää ostopolttoaineiden tarvetta. Diplomityössä tutkitaan sellutehtaan sekundäärilämpöjärjestelmän toimintaa, ohjausta ja energiankulutusta. Sekundäärilämpöjärjestelmästä muodostetaan taseet talvitilanteessa ja samalla etsitään mahdollisia uusia talteenotettavia sekundäärilämpövirtoja tai vastaavasti käyttökohteita. Lisäksi päivitetään sekundäärilämpöjärjestelmän raportoinnin ja ohjauksen työkaluja nykytilannetta vastaavaksi. Työn aikana kiinnitetään myös huomiota järjestelmän toimintaan muutostilanteissa, joissa kaikkia vesijakeita ei välttämättä ole saatavilla prosessin tarvitsemia määriä.

Earnings quality and performance in the banking industry: a profit frontier approach

The analysis of efficiency and productivity in banking has received a great deal of attention for almost three decades now. However, most of the literature to date has not explicitly accounted for risk when measuring efficiency. We propose an analysis of profit efficiency taking into account how the inclusion of a variety of bank risk measures might bias efficiency scores. Our measures of risk are partly inspired by the literature on earnings management and earnings quality, keeping in mind that loan loss provisions, as a generally accepted proxy for risk, can be adjusted to manage earnings and regulatory capital. We also consider some variants of traditional models of profit efficiency where different regimes are stipulated so that financial institutions can be evaluated in different dimensions—i.e., prices, quantities, or prices and quantities simultaneously. We perform this analysis on the Spanish banking industry, whose institutions have been deeply affected by the current international financial crisis, and where re-regulation is taking place. Our results can be explored in multiple dimensions but, in general, they indicate that the impact of earnings management on profit efficiency is of less magnitude than what might a priori be expected, and that on the whole, savings banks have performed less well than commercial banks. However, savings banks are adapting to the new regulatory scenario and rapidly catching up with commercial banks, especially in some dimensions of performance.

Do isolamento à síntese da convolutamidina A

Convolutamydine A is a member of a family of oxindole alkaloids isolated from the Floridian marine bryozan Amathia convoluta in 8.6x10-6 % yield. This compound is interesting as it has been described in the literature to have significant pharmacological activity. When bioactive substances are isolated in low yields, such as in the case of convolutamydine A, the use of synthetic organic chemistry to prepare larger quantities of these substances is necessary. This paper describes the isolation, structural characterization and synthesis of convolutamydine A, using readily available reagents and reaction conditions that may be applied in any organic chemistry undergraduate laboratory course.

Resíduos de agrotóxicos em alimentos: uma preocupação ambiental global - Um enfoque às maçãs

This paper describes the use of pesticides in agriculture. Research has shown that significant quantities of pesticide residues have been found in many types of foods. Thus, an overview is given of pesticide residue determinations in fruits and vegetables, with special attention to apples. The toxicity and the adverse effects possibly caused by the exposure of these compounds are alerting the scientific community to develop studies about the validation of analytical methods for multiresidue pesticide determination in these samples. This review shows that pesticide-residue determination in apples is becoming a very important and challenging issue.

Caracterización del proceso de adsorción de 3-cloro fenol desde solución acuosa sobre carbon activado por calorimetria de inmersión

The immersion enthalpy of activated carbon in 3-chlorophenol solutions, of 100 mg L-1, is determined at different pH values between 3 and 11 with results between 37.6 and 21.2 J g-1. The 3-chlorophenol adsorbed quantities on the activated carbon during the calorimetric experience, are between 1.13 and 2.19 mg g-1, for different pH values of the solution. The 3-chlorophenol adsorbed quantity and the immersion enthalpy decrease by increasing of the pH solution, while increasing the adsorbed quantity increases the immersion enthalpy value.

Tocoferois e tocotrienois em óleos vegetais e ovos

The distribution and content of vitamin E isomers was investigated in vegetable oils and raw and cooked egg yolk in commercial restaurants. The analysis of the eight vitamin E isomers was carried out by High Performance Liquid Chromatography (HPLC) with fluorescence detection. The tocopherol and tocotrienol composition of foods varied considerably. Tocopherols were detected in greater quantity and frequency. The α-tocopherol predominated in egg yolks and olive oil while γ-tocopherol was found in high quantities in soybean and canola oils. Cooking did not cause major losses for most of the vitamin E isomers in egg yolks.

Comparação entre um trocador aniônico de sal de amônio quaternário de quitosana e um trocador comercial na extração de fósforo disponível em solos

The present work aimed modify chemically the chitosan (QTS) surface to obtain a reticulate chitosan quaternary ammonium salt (SAQQR), and compare this anionic exchanger with an commercial ion exchanger in the extraction of available phosphorus in soils. The results showed that the two exchangers are identical, extracting similar and proportional quantities of available phosphorus in the studied soils, and the anionic exchanger of SAQQR provides a high chemical stability, not affected by the pH difference of soils.

Avaliação físico-química de efluente gerado em biodigestor anaeróbio para fins de avaliação de eficiência e aplicação como fertilizante agrícola

The use of biodigester for basic and environmental sanitation has large demand in Brazil. A biodigester was built to treat conjunctly the human and pig feces and urine, regarding to its future application in rural small towns. The results show that the biodigester can reduce 90% of COD and BOD and, up to 99.99% of thermotolerant coliforms. The treated effluent has variable quantities of macro- and micro-nutrients; and organic matter. However, the concentration variability of the nutrients makes difficult a dosed application into soil. The soluble salts (mainly as Na+ form) make necessary a controlled use to avoid environmental degradation.