Encontrados 14 documentos, a visualizar página 1 de 2
Proportion, composition and potencial N mineralisation of particle size fractio...
Fangueiro, D.; Gusmão, M.; Grilo, J.; Porfirio, G.; Vasconcelos, E.; Cabral, F.Research Paper ; Mechanical slurry separation is a useful technology for slurry management on farms. The characteristics of the fractions obtained depend on the separation efficiency and on the characteristics of the original slurry. In the present work, three types of slurry e pig, cow and duck e were separated into 4 particle size fractions. The proportion, composition in terms of carbon and nutrients as nit...
Carbon and nitrogen mineralization of organic wastes from sugarcane distillerie...
Vasconcelos, E.; Cabral, F.; Pita, V.; Fangueiro, D.; Ribeiro, H.M.RAMIRAN International Conference ; In Madeira Island (Portugal) significant amounts of wastes are generated in sugarcane distilleries, namely vinasse (the remaining fermented must after distillation) and yeast waste (the yeast surplus produced during the alcoholic fermentation). These wastes have high organic loads and low pH, leading to serious environmental problems when released directly into natural waterc...
Assessment of CO2 emissions during acidification, storage and after incorporati...
Fangueiro, D.; Gusmão, M.; Surgy, S.; Cabral, F.RAMIRAN International Conference ; Large amounts of pig slurry are produced each year in Portugal leading to environmental problems such as water and air pollution. Previous studies have reported that livestock production is the main source of anthropogenic ammonia (NH3) emissions in Europe (Kai et al., 2008) and an important source of greenhouse gases (Weiske and Petersen, 2006). Effluent treatment has been p...
Influence of the particle size and animal slurry type on the potential of nitro...
Fangueiro, D.; Gusmão, M.; Grilo, J.; Vasconcelos, E.; Cabral, F.RAMIRAN International Conference ; Animal manures are rich in organic matter and nutrients, namely nitrogen (N) and, consequently, widely applied to soil as organic fertilizers. However, a large part of the nitrogen contained in animal manures is in the organic form and so not directly available for plants. Indeed, organic N has to be mineralized prior to plant uptake (Rees and Castle, 2002). Several manure ch...
Assessment of N mineralization and leaching in soil using a new in-situ incubat...
Cabral, F.; Sousa, J.R.; Coutinho, J.RAMIRAN International Conference ; Towards sustainable soil management, the application of organic residues to the soil has to be based on criteria sustained by experimental studies. Several methods for estimating the amount of N that mineralizes from landapplied organic residues can be used but laboratory incubations has been the main methodology used due to several advantages related to practical and economi...
Extraction of bixin from annatto seeds using supercritical carbon dioxide
Silva,G. F.; Gamarra,Felix M. C.; Oliveira,A. L.; Cabral,F. A.The solubility of 93% pure bixin in supercritical carbon dioxide (SC-CO2) and of the bixin present in annatto seeds (Bixa orellana L.) was measured. For the seeds, the measurements were made in a temperature range from 30 to 50ºC and pressure between 10 and 35 MPa and for the pure bixin, at 40ºC from 10 to 35 MPa. The main pigments of annatto seeds are bixin and norbixin, but the extracts only showed the presen...
Short-term effects on soil properties and wheat production from secondary paper...
Nunes, J. Rato; Cabral, F.; López-Piñeiro, A.This study was conducted under greenhouse conditions to evaluate the potential use of SPS as a fertilizer, amendment and/or liming agent for wheat (Triticum aestivum L.). Two representative Mediterranean agricultural soils, a Cambic Arenosol (cmAR) and a Cromic Cambisol (crCM) were used. Treatments included four sludge rates ranging from 0 to 40 g kg 1 (equivalent of 0, 38, 88 and 120 Mg ha 1). A significant in...
Use of pulp mill inorganic wastes as alternative liming materials
Cabral, F.; Ribeiro, H.M.; Hilário, L.; Machado, L.; Vasconcelos, E.A laboratory aerobic incubation study was performed during 18 weeks under controlled conditions to assess the effects of applying different doses of pulp mill inorganic wastes on the physical–chemical properties of an acid Dystric Cambissol. Three different inorganic wastes were tested – wood ash, dregs and grits, and an agriculture limestone was used as reference. Results showed that increasing the dose applie...
Influence on the quality of essential lemon (Citrus aurantifolia) oil by distil...
Gamarra,F. M. C.; Sakanaka,L. S.; Tambourgi,E. B.; Cabral,F. A.The essential oil of key lime (Citrus aurantifolia) was obtained by steam distillation at normal conditions (1.0 bar/25ºC) with steam at 110ºC, during 10h. The GC analysis identified about 10 main substances, being limonene, p-cymene, myrcene and beta-bisabolene the most significant compounds. Aldehyde content increased significantly during distillation time (upper phase). After 10h of process, oil has presente...
Reentrant spin glass behavior in polycrystalline La0.7Sr0.3Mn1-X FeX O 3
Xavier Jr.,M.M.; Cabral,F.A.O.; de Araújo,J.H.; Dumelow,T.; Coelho,A.A.The magnetic and transport properties of the compound La0.7Sr0.3Mn1-xFe xO 3 (0.1 < x <0.4) have been studied by means of electrical resistivity, AC magnetic susceptibility, and DC magnetization. At low concentrations (x <0.1), the system displays essentially para-to-ferromagnetic transitions as the temperature is decreased, although a decrease in the magnetic moment has been observed in previous studies at tem...
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