Estudo das propriedades térmicas de materiais aplicados em paredes divisórias leves

Para o presente estudo das propriedades térmicas de paredes divisórias leves foi considerada uma parede composta por isolamento (como núcleo) e membranas (como revestimento). Avaliou-se comparativamente o desempenho térmico dos materiais de isolamento aplicados a paredes divisórias: poliestireno expandido (EPS), espuma de poliuretano (PU), estruturas tridimensionais do tipo sandwich em poliéster (3DWK), aglomerados de coco (CKE), fibra de coco (CKF), lã de rocha (RW), fibra reciclados (WF), fibras de sisal (SF), fibras de poliéster (PESF). O objectivo deste estudo é comparar o desempenho térmico dos materiais de isolamento à base de polímeros ou fibras têxteis com os valores de referência das paredes divisórias leves convencionais, produzidas com painéis de gesso cartonado e isolamento em lã de rocha. As conclusões do trabalho permitem quantificar as principais vantagens e desvantagens dos diferentes isolamentos no que diz respeito ao desempenho térmico de divisórias

Effect of dairy effluents pre-treatment on N2O emissions and N-organic degradation after soil application

Nitrous oxide (N2O) is a potent greenhouse gas that plays a key role in climatic forcing contributing to the greenhouse effect by about 4 %, and also contributes to stratospheric ozone depletion. Cattle slurries are commonly applied to agricultural soils, inducing an increase of soil nitrous oxide emissions. Therefore, many procedures were developed for slurry pre-treatment in order to improve soil slurry application and reduce nitrogen losses, namely N2O emissions. The aim of this work was to compare N2O emissions and the kinetic of N organic degradation from treated and untreated cattle-slurry after its incorporation in agricultural soils

Separação de sólidos e nutrientes com PAM e bentonite em chorumes bovinos

A separação de sólidos do chorume e a aplicação de agentes floculantes à fracção líquida obtida constituem processos de tratamento deste efluente pecuário que permitem a obtenção de materiais com características distintas que ampliam as opções de utilização e de gestão do chorume. A redução do teor de sólidos e nutrientes na fracção sobrenadante apresenta vantagens em termos de odores, armazenamento, tratamento, aplicação aos solos e irrigação. Este trabalho teve como objectivo avaliar a utilização dos agentes floculantes poliacrilamida (PAM) e bentonite na remoção de sólidos e nutrientes da fracção líquida do chorume de explorações de bovinicultura leiteira. O trabalho experimental decorreu em Vila do Conde durante 2004, numa exploração de bovinicultura leiteira intensiva. O chorume bruto foi sujeito a separação mecânica de sólidos. Posteriormente a fracção líquida obtida foi bombeada para recipientes, e definiram-se 3 tratamentos com 2 repetições: controlo, adição de 200 mg L -1 de PAM e adição de 2 g L -1 de bentonite. Após a aplicação dos floculantes foram recolhidas amostras às fracções sobrenadante e sedimentada nos tempos 0, 2, 4, 20 e 30 horas. Essas amostras foram analisadas relativamente à concentração de N Kjeldahl, P e K totais, N-NH4 + , P solúvel em água, C orgânico solúvel em água, valor de pH e %MS. A separação mecânica do chorume bruto conduziu a uma eficiência de remoção pela fracção sólida obtida de 22, 25, 44 e 21%, respectivamente, dos teores de N Kjeldahl, P total, P solúvel em água e MS. Quanto à capacidade de remoção dos floculantes, a aplicação de PAM conduziu à eficiência de remoção da fracção sobrenadante de 46, 40, 65, 57 e 40%, respectivamente para o N Kjeldahl, P e K totais, P solúvel em água e MS; e a aplicação de bentonite a remoções de 19, 21, 11, 16 e 12%

Characterization of porous acoustic materials applied to lightweight partition walls

The increased need to save material and energetic resources, allied with a growing concern on the environmental issues and incertitude on the evolution of the economy, has impelled minimalist-approaches to Architecture and Engineering, reducing to the minimum necessary expression the building elements. The development of new lightweight materials, most of them composites with fibrous reinforcement systems, has interest for building materials and textile industries. However, these materials still do not have a significant implementation in the building industry or, at least, this implementation is not being made exploring all their potentialities. Non load bearing interior partition walls are thin elements built to divide the indoor space into rooms or other compartments. Porous materials applied in interior partition walls have a significant importance in these building elements because sound insulation is an important requirement. Walls must provide an airborne sound barrier between rooms in a same dwelling and especially between different dwellings, this last issue as a compulsory requirement to fulfil in Portuguese regulations. In the present study it will be considered a lightweight interior partition wall composed by insulation material and layered within two membranes. The process of selecting materials for that interior partition wall is a challenging task. This paper intends to compare results of functional (acoustic and thermal) performance of materials such as expandable polystyrene (EPS), polyurethane foam (PU), Ethylene-vinyl acetate (EVA), 3D warp knitted polyester fabrics (3DWK), Cork (CK), Expanded Cork (CKE), Rockwool (RW), coconut fibber (CCF), silicone (SI), waste fiber (WF), to discuss about their potentialities as insulation or membrane materials applied in interior dividing walls technologies. It also presents a morphological characterization of materials, through microscopic analysis, in order to define the relationship between the morphology and acoustic performance. The results of tests are compared with reference values of rock wool as insulation material - conventionally used in lightweight dividing walls made of plasterboard leaves and light gauge steel framing structure. One of the results of this paper is that a lightweight and thin interior partition wall filled with insulation material present acoustic advantages when compared with a heavyweight interior partition wall with more thickness. The concept of membrane goes back to the Latin word “membrana”, meaning parchment or skin. In previous studies it could be verified that low density makes membrane structures poor thermal and acoustic insulators. However, it is available in the market heavily coated or microperforated membranes that have dampening effect A low density generally also implies a high porosity or a high volume of voids, which leads to a decrease in the thermal conductivity. In previous studies from the same authors, it was concluded that the presence of air gap between insulation materials in a lightweight interior partition can increase the acoustic insulation between 2 to 5 dB, the inclusion of porous materials in the air gap can contribute between 1 to 4 dB in thicknesses till 10cm. The compromise between thermal and acoustic performance should also be attended. However thermal performance is only a requirement for interior partition walls between useful and non useful areas in housing buildings. In this study it will be presented results for different densities of insulation material. In the process of airborne sound transmission between two spaces, should be distinguished: a) direct transmission, that occurs directly through the separation element; or b) marginal transmission - that occurs through other building elements interlocked to the element of separation in study. The direct transmission can occur through joints, cracks or discontinuance of the construction element or through the construction element vibration. The heat transfer coefficient calculation tests were conducted according UNE EN 6946. The sound insulation estimation between locals was conducted according to EN 12354-1. Procedures for measuring the reverberation of a room, the absorption of the covering layers, as well as the sound absorption coefficients of a specimen of sound absorptive material were made according to ASTM C – 423

Impact of cattle slurry treatment by separation and acidification on gaseous emissions after soil application

Objectives: Cattle-slurry management became a priority in many livestock farms and slurry treatment is used to increase the fertilizer value of slurry and/or minimize its environmental impact. Indeed, significant emissions of ammonia (NH3) and greenhouse gases (GHG) as nitrous oxide (N2O), carbon dioxide (CO2) and methane (CH4) can occur during and after slurry application to soil. Application of acidified slurry or liquid fraction (LF) obtained by solid-liquid separation are two alternatives to raw slurry application that have proven to be efficient to minimize ammonia emissions. However, few is known about its effect on GHG emissions. The aim of the present work was to assess the efficiency of cattle slurry treatment by acidification and/or solid liquid separation to mitigate ammonia (NH3) and greenhouse gases (GHG) emissions following surface application to a sandy loam soil

Influence of two nitrification inhibitors (DCD and DMPP) on annual ryegrass yield and soil mineral N dynamics after incorporation with cattle slurry

Nitrogen (N) losses through nitrate leaching, occurring after slurry spreading, can be reduced by the use of nitrification inhibitors (NIs) such as dicyandiamide (DCD) and 3,4-dimethyl pyrazole phosphate (DMPP). In the present work, the effects of DCD and DMPP, applied at two rates with cattle slurry, on soil mineral N profiles, annual ryegrass yield, and N uptake were compared under similar pedoclimatic conditions. Both NIs delayed the nitrate formation in soil; however, DMPP ensured that the soil mineral N was predominantly in the ammonium form rather than in the nitrate form for about 100 days, whereas with DCD such effect was observed only during the first 40 days after sowing. Furthermore, the use of NIs led to an increase of the drymatter (DM) yields in a range of 32–54% and of the forage N removal in a range of 34–68% relative to the slurry-only (SO) treatment (without NIs). A DM yield of 8698 kg ha21 was obtained with the DMPP applied at the greater rate against only 7444 kg ha21 obtained with the greater rate of DCD (4767 kg ha21 in the SO treatment). Therefore, it can be concluded that DMPP is more efficient as an NI than DCD when combined with cattle slurr

Influence of the particle size and animal slurry type on the potential of nitrogen mineralization after soil incorporation

RAMIRAN International ConferenceAnimal 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 characteristics as the C:N ratio (Chadwick et al., 2000), the lignin content (Kristensen, 1996) and the NH4 +/organic N ratio (Beauchamp and Paul, 1989) have been suggested as indicators of the plant-available N. More recently, Fangueiro et al. (2008) showed that the potential of N mineralization (PNM) of cattle slurry is inversely correlated with slurry particle size: finest fractions are the particle-size fractions from which N mineralization occurs in slurries whereas coarser fractions are associated with immobilization. Furthermore, Moller et al. (2002) reported that animal diet and anaerobic decomposition during storage in slurry channels and stores affect the slurry particle size distribution. Such information is of great interest since the finest slurry particle size should infiltrate the soil more easily and quickly relative to the coarser slurry particle size that should remain close to soil surface. Furthermore, mechanical slurry separation is now performed in many pig and dairy farms in order to improve slurry management in terms of nutrients utilization and reducing costs related to slurry storage. Slurry separation by screw press leads to a nutrient rich organic solid fraction (0.7– 3.2 mm particles) that may be composted and a liquid fraction that can be used for fertigation. In the present study, three types of slurry (pig, duck and cattle) were separated into 4 slurry particle size fractions (>2000 um, 2000-500 um, 500-100 um, <100 um) in order to assess the influence of the type of slurry and slurry particle size on the PNM after soil incorporation

New eco-friendly hybrid composite materials for civil construction

This paper concerns the development of new hybrid composite materials using granulated cork, a by-product of cork industry, cellulose pulp, from recycling of paper residues, and hemp fibres. The binder used is either cellulose pulp or lime-pozzolan mixture. Such materials may be used as composite boards and mortars for non structural elements of construction, such as dry walls and ceiling or floor levelling and filling. The possibility of using these composites in conjugation with light structural supports has been studied. The paper will present the properties and the manufacturing methods used to produce the above mentioned promising eco-friendly composites that can unfold ways of using industrial wastes as new construction materials with excellent inherent thermal and acoustic properties