880 resultados para MOISTURE-CONTENT


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The aim of this research consisted in the use of wastes from tropical wood (Cordia goeldiana) with low density and the polyurethane resin (mono and bicomponent) castor oil based in the manufacture of particleboards, generating subsidies as application in rural and civil construction, as well in the furniture industry. The particleboards were manufactured with 15% of polyurethane resin content (one part of pre-polymer and one part of polyol), compaction pressure of 4MPa, pressing temperature of 90 degrees C and press time of 7 minutes. The physical and mechanical properties investigated were density, moisture content, strength modulus in bending and internal bond, both obtained according to the recommendations of the Brazilian standard ABNT NBR 14810:2002. The mean values obtained for these properties were systematically superior to the Brazilian standard requirement. This point showed that it is possible the use of Cordia goeldiana wastes in the particleboard production. We confirmed the hypothesis of a significant linear relation between density and the internal bond of the panels, allowing the estimation of the internal bond of particleboards.

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The aim of this study was to adapt the methodology of the accelerated aging and electrical conductivity tests for determination of physiological potential in crambe seeds. Six seed lots of crambe (cv. FMS Brilhante) were subjected to determination of moisture content, germination test, first count germination, emergence, and emergence speed index. For the accelerated aging test, the traditional methodology was used with water, and with a saturated potassium chloride and sodium chloride solution in three periods of exposure (24, 48, and 72 hours) at 41 degrees C; the electrical conductivity test was performed with four pre-soaking treatments (0, 2, 4, and 8 hours) and four soaking periods (4, 8, 16, and 24 hours) at 25 degrees C. The accelerated aging test with water for 72 hours and the electrical conductivity test with 2 hours of pre-soaking and assessment after 16 hours were effective for classification of the crambe seed lots in regard to physiological quality.

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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Composting is considered a process that enables adding value to organic solid waste turning them into organic fertilizer. In this process, factors such as mishandling the windrow, failed to control the temperature, aeration and moisture content will result in the quality of waste decomposition, and thus affect the quality of the final compound. Decentralized systems such as home composting, composting in restaurants, food courts and schools are one of the solutions for valuing these waste in a non expensive way and with greater quality. For this purpose, the project aims to analyze the conditions for composting of solid waste of the University Restaurant of Rio Claro- SP, through two different composting systems: manual revolving windrow and static pile. It was found that in University Restaurant (RU) on average 33% by weight of the total waste generated in the property are capable of composting. In this sense, in order to investigate the preliminary process operation parameters were mounted one manual windrow composed of 100% of the UR waste and a static pile composed of 60% of the UR waste and 40% of pruning and grass residues (PG). This study analyzed the manual revolving windrow and static pile systems for the parameters: moisture content, pH, C / N ratio and temperature. The study of the proportions of the PG and UR waste pointed to the need for pruning and grass residues addition for composting, considering that the manual revolving windrow composed by 100% of the UR waste had no satisfactory performance due to low temperatures measured during 60 days analysis. The best ratio for manual revolving windrow method analyzed in this study was 60% of the UR waste and 40% of PG waste, in dry weight. From this proportion a static pile was assembled, composed of 60% of UR waste e 40% of PG waste from the maintenance activities of the green area of the university. The biological activity in the static pile reached the maximum temperature of ...

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

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Oxycarotenoids concentration in layer hens’ feed may be increased whenever the consumer market demands for more pigmented egg yolks. Oxycarotenoids present in Rubrivivax gelatinosus biomass grown in industrial wastewater have already proved their ability on enhancing yolk color. Moreover, there is a current interest on the antioxidant properties that some carotenoids may provide to food and health. So, in this experiment, we investigated the effects of oxycarotenoids supplementation in hens´ diets on yolk composition and stability to rancidity. Hy line hens aging 19 weeks were individually housed in wire cages equipped with feeders and drinkers. After 15 days receiving a corn basal diet nutritionally balanced, they were assigned to four different treatments, with six replicates, that lasted for 28 days: T1 – basal diet (control), T2 – basal diet + 1.5 mg/kg canthaxanthin, T3 – basal diet + 4.5 g/kg freeze dried R. gelatinosus biomass and T4 - basal diet + 4.5 g/kg spray dried R. gelatinosus biomass. Eggs laid on the last 5 days of rearing were collected; the yolks were separated, analyzed for pH and then freeze dried for the further analyses. Proximate composition was determined after drying and the rancidity (TBRAS method) was investigated at 0, 30 and 60 days of storage at room temperature/dark conditions. Yolks that received the oxycarotenoids had the lowest moisture content and the highest protein contents (P < 0.05). Lipids and pH were the same for all treatments (P > 0.05) and ashes only were higher for T2 (P < 0.05). All treatments that received oxycarotenoids had lower TBARS than control group and, among them, oxycarotenoids from spray dried R. gelatinosus biomass were the most effective to prevent rancidity (P < 0.05). So, we concluded that the use of R. gelatinosus biomass in hens feed brings positive effects to the yolk quality, since protein content is increased and conservation is increased due to decreased water content and lipid oxidation.

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A thermotolerant strain of Rhizopus oryzae was grown in three agro-industrial by-products: brewers’ rice, corn grits and wheat bran. Different substrates, cultivation time, moisture content, additional nitrogen sources, pH and temperature of incubation were evaluated aiming to optimize growing conditions. The highest enzymatic activity was observed after 24 h of cultivation using wheat bran as substrate with the following salt solutions: NH4NO3, MgSO4.7H2O and (NH4)2SO4 0.1% at temperature of 35°C. It was observed that changes in the pH range 4.0-6.0 did not significantly affect α-amylase activity. The optimum operation conditions were 75°C and pH 4.5. The enzymes remained stable at 75°C in the absence of substrate for 25 min.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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The bamboo waste can be an alternative material to sustain the crescent demand for particleboards, also bringing ecological benefits as reduction of the pressure for raw materials and landfill space demands. In this context, this research aimed to manufacture and determine some physical and mechanical properties of particleboards with bamboo waste particles (Dendrocalamus giganteus), obtained from different sources, bonded with four different percentages of urea–formaldehyde (UF) based resin (6%, 8%, 10% and 12% related to dry material of particles). Response variables investigated were: density; moisture content; thickness swelling in 2 and 24 hours; water absorption in 2 and 24 hours; internal adhesion (STpe); strength in tension parallel to faces (STpa); modulus of elasticity (MOE) and modulus of rupture (MOR). Results permitted to conclude that particleboards as mentioned showed good performance only in the physical properties requirements imposed by Brazilian Standard NBR 14810, but this was not observed to mechanical properties considered. New researches are needed in order to optimize the producing process parameters.

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The problem of proper disposal of solid waste generated in different industrial processes is one of worldwide environmental concerns nowadays. Thus, this study aimed to establish a new alternative for the disposal of two agro-industrial residues employing them to produce particleboard for different purposes in building construction. The focus was given to the reuse of the sugarcane bagasse (SB) originated during the processing of Saccharum officinarum for sugar and ethanol production, and bamboo stem leaves of Dendrocalamus giganteus(BB). For this, six particleboards were produced in the following compositions: with 100% SB, 75% SB + 25% BB, 50% SB+50% BB, 40% SB +60 BB, 25% SB+ 75% BB and 100% BB in the total mass of the composites. The particleboards physical characterization followed Brazilian Standard ABNT NBR 14810-3 to density, moisture content and water absorption. Results showed these raw materials are compatible to particleboard production.

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This study aims to determine physical properties of particleboard made of sawmill waste, as a mix of several wood species, and two adhesives: urea-formaldehyde, usually employed in industry (even with drawbacks or formaldehyde emission during pressing) and FASTBOND®, water based resin, still poorly referenced in literature. Sixteen panels have been produced, in four experimental conditions, defined by using two adhesives and a 12 mm thick limiter (or not). Variance analysis was adopted to evaluate influence of experimental conditions on physical properties of produced panels, manufactured in nominal dimensions 350x350mm; 10% resin related to particles mass (at 5% moisture); 3.5 MPa compaction pressure, temperature 130°C, in a 10 min cycle. Tests to determine density, moisture content, swelling and water absorption were carried out based on normative parameters of ABNT NBR 14810:2006. Results have been satisfactory to panels produced with urea-formaldehyde but those manufactured with polychloroprene based resin (FASTBOND®) not meet regulatory requirements. Best results have been obtained without limiter.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)