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Aderência de chapiscos em concretos estruturais - melhoria da microestrutura da zona de interface pela adição da sílica da casca de arroz; Adherence of slurry mortars in structural concretes – microstructure improvement of the interfacial transition zone through addition of silica obtained from rice husk

Silva, Vanessa Silveira
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 09/02/2004 PT
Relevância na Pesquisa
37.45%
Avaliação da aderência de chapiscos em substratos de concretos estruturais. Com o objetivo de aprimorar a microestrutura da zona de interface argamassa/concreto e aumentar a resistência de aderência do revestimento, utilizou-se chapisco com baixa relação água/aglomerante e adição da sílica ativa extraída da casca de arroz como tratamento da zona de interface da argamassa e substrato. Para avaliar a aderência do revestimento realizaram-se ensaios de determinação da resistência de aderência à tração. Utilizou-se a técnica de microscopia eletrônica de varredura associada à espectrografia por dispersão de energia para analisar a microestrutura da zona de interface do chapisco e concreto. Os resultados do programa experimental evidenciaram que, quando se utiliza a sílica extraída da casca de arroz no chapisco, em teores de 5% em relação à massa de cimento, há aumentos significativos de resistência de aderência do revestimento. Nos estudos microestruturais, foi possível observar que devido às ações físicas e químicas da sílica da casca de arroz, formou-se uma microestrutura densa, de baixa porosidade e com a presença de produtos hidratados pouco cristalinos na interface chapisco/concreto. A implementação de uma ponte de ligação constituída por chapiscos com sílica ativa...

Aderência de revestimentos externos de argamassa em substratos de concreto : influência das condições de temperatura e ventilação na cura do chapisco; External mortar rendering bond in concrete substrates : influence of temperature and ventilation conditions during the slurry layer curing

Moura, Cristiane Borges
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
37.48%
A prevenção de manifestações patológicas em revestimentos de argamassa, em especial os descolamentos, é refletida no interesse das empresas construtoras e pesquisadores por um maior conhecimento das propriedades dos elementos constituintes do sistema, bem como dos fatores externos. Destes pode-se citar as variáveis que intervêm nos mecanismos de aderência, porém que não são controláveis, como a temperatura, umidade e ventilação. Neste contexto, o presente trabalho objetiva analisar a influência da ação do vento e da temperatura elevada durante a cura da argamassa de chapisco na aderência dos revestimentos externos de argamassa aplicados em substratos de concreto. Foram moldados prismas nas dimensões 40x45x10cm, com resistência aos 28 dias de 37MPa. Utilizou-se 3 argamassas de chapisco, uma dosada em obra com traço 1:5,67 (em massa com areia seca) e outras duas industrializadas de diferentes fabricantes. Também foram utilizadas 3 argamassas de revestimento, uma dosada em obra com traço 1:0,78:6,5 (em massa com areia seca), e outras duas industrializadas de diferentes fabricantes, sendo os mesmos das argamassas de chapisco. Combinou-se os tipos de argamassa de chapisco e revestimento juntamente com o modo de preparo de cada para a composição de diferentes sistemas de revestimento...

Aderência de revestimentos de argamassa em substrato de concreto : influência da forma de aplicação e composição do chapisco; Mortar rendering bond in concrete substrate: influence of the application form and composition of slurry mortar

Gasperin, Josiane
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
37.58%
Revestimentos de argamassa, embora largamente utilizados, ainda e cada vez mais, geram interesse, tanto por parte do meio acadêmico quanto pelas empresas construtoras. Este fato se deve pela, sempre presente, necessidade de melhoria da tecnologia, visando, principalmente, maior conhecimento dos elementos constituintes do sistema de revestimento e, também, devido ao grande número de manifestações patológicas ocorridas neste tipo de revestimento, em especial o descolamento. Neste contexto, este trabalho teve como objetivo avaliar a influência da camada de preparo da base, o chapisco, quanto a sua forma de aplicação e composição, na resistência de aderência de revestimentos de argamassa aplicados sobre substrato de concreto de baixa porosidade. Para isso, foram moldadas placas de concreto com dimensões de (35x25x5)cm e resistência, aos 28 dias de, aproximadamente, 30MPa, que receberam argamassa de chapisco e posteriormente foram revestidos com argamassa de revestimento. Afim de isolar o efeito do chapisco, nesta pesquisa, o substrato de concreto e a argamassa de revestimento foram mantidos fixos, sendo, então, o chapisco o único elemento variável do sistema. Em relação ao chapisco variou-se sua forma de aplicação (manual e mecanizada)...

Mitigation of N2O emissions from grassland by nitrification inhibitor and actilith F2 applied with fertilizer and cattle slurry

Merino, P.; Estavillo, J. M.; Graciolli, L. A.; Pinto, M.; Lacuesta, M.; Muñoz-Rueda, A.; Gonzalez-Murua, C.
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 135-141
ENG
Relevância na Pesquisa
37.4%
Nitrous oxide (N2O) is involved in both ozone destruction and global warming. In agricultural soils it is produced by nitrification and denitrification mainly after fertilization. Nitrification inhibitors have been proposed as one of the management tools for the reduction of the potential hazards of fertilizer-derived N2O. Addition of nitrification inhibitors to fertilizers maintains soil N in ammonium form, thereby gaseous N losses by nitrification and denitrification are less likely to occur and there is increased N utilization by the sward. We present a study aimed to evaluate the effectiveness of the nitrification inhibitor dicyandiamide (DCD) and of the slurry additive Actilith F2 on N2O emissions following application of calcium ammonium nitrate or cattle slurry to a mixed clover/ryegrass sward in the Basque Country. The results indicate that large differences in N2O emission occur depending on fertilizer type and the presence or absence of a nitrification inhibitor. There is considerable scope for immediate reduction of emissions by applying DCD with calcium ammonium nitrate or cattle slurry. DCD, applied at 25 kg ha-1, reduced the amount of N lost as N2O by 60% and 42% when applied with cattle slurry and calcium ammonium nitrate...

Integrated approach for effective bioethanol production using whole slurry from autohydrolyzed Eucalyptus globulus wood at high-solid loadings

Romaní, Aloia; Ruíz, Héctor A.; Pereira, Francisco B.; Teixeira, J. A.; Domingues, Lucília
Fonte: Elsevier BV Publicador: Elsevier BV
Tipo: Artigo de Revista Científica
Publicado em //2014 ENG
Relevância na Pesquisa
37.27%
One of the most important targets and challenges in the second generation bioethanol is the development of a cost-effective process on large-scale. In this context, the high solid loading on saccharification and fermentation and the use of whole-slurry from pretreatment could be promising alternatives to obtain high ethanol concentrations and to decrease operational costs and wastewater. In this work, Eucalyptus globulus wood was submitted to non-isothermal autohydrolysis treatment (Tmax = 210 °C) and the whole-slurry obtained was assayed for the optimization of enzymatic saccharification at different solid and enzymes (CTec2 and HTec2) loadings using a Box–Behnken experimental design. Under the optimized conditions (liquid solid ratio 6.4 g/g, cellulase to substrate ratio 22.5 FPU/g and hemicellulase to substrate ratio 500 UI/g), two strategies were evaluated for ethanol production (Simultaneous Saccharification and Fermentation, SSF and Presaccharification and Simultaneous Saccharification and Fermentation, PSSF), using an industrial and robust Saccharomyces cerevisiae strain. High concentrations of ethanol (50.2 and 48.8 g/L) and productivities (0.63 and 0.55 g/L h) were obtained by SSF and PSSF, respectively. The SSF process proved to be an advantageous strategy to obtain concentrations >6% (v/v) of ethanol with elevated conversion (95%) even employing high solid loading and non-detoxified hydrolysate. Following an integrated optimization process...

Assessment of CO2 emissions during acidification, storage and after incorporation to soil of pig slurry

Fangueiro, D.; Gusmão, M.; Surgy, S.; Cabral, F.
Fonte: Cordovil, C. e Ferreira, L. Publicador: Cordovil, C. e Ferreira, L.
Tipo: Conferência ou Objeto de Conferência
Publicado em /09/2010 ENG
Relevância na Pesquisa
37.58%
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 promoted to improve slurry management and to reduce its environmental impact (Sommer and Hutchings, 2001, Fangueiro et al., 2008a). Solid-liquid separation of slurry is a useful tool at the farm level producing valuable fractions, a liquid that can be used for direct fertilisation and a solid fraction that can be composted (Fangueiro et al., 2008b). Alternatively, acidification of slurry has been proposed to reduce ammonia (NH3) emissions during storage and field application (Kai et al., 2008). Previous works (Misselbrook et al., 2005; Fangueiro et al., 2008a) reported that higher NH3 emissions occurred during storage of liquid fraction of slurry or manure with low dry matter content, probably due to a reduced crust formation that decreases NH3 emissions. Hence, acidification of the liquid fraction of slurry is strongly recommended. Slurry acidification is common practice in The Netherlands and Denmark (Schils et al....

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

Fangueiro, D.; Gusmão, M.; Grilo, J.; Vasconcelos, E.; Cabral, F.
Fonte: Cordovil, C. e Ferreira, L. Publicador: Cordovil, C. e Ferreira, L.
Tipo: Conferência ou Objeto de Conferência
Publicado em /09/2010 ENG
Relevância na Pesquisa
37.62%
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 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...

Proportion, composition and potencial N mineralisation of particle size fractions obtained by mechanical separation of animal slurry

Fangueiro, D.; Gusmão, M.; Grilo, J.; Porfirio, G.; Vasconcelos, E.; Cabral, F.
Fonte: Elsevier Publicador: Elsevier
Tipo: Artigo de Revista Científica
Publicado em //2010 ENG
Relevância na Pesquisa
37.54%
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 nitrogen (N) phosphorus (P) and potassium (K) was evaluated. The potential of N mineralisation of whole slurries, and each fraction after soil application, was assessed. Results of the study showed that the characteristics of the slurry fractions obtained depend strongly on the slurry type considered, namely on its dry matter (DM) content. A positive value of PNM was observed with the 3 slurry types and 4 fractions considered, indicating that no N immobilisation occurred. Nevertheless, results showed that the value of PNM vary significantly (P < 0.05) with slurry types and slurry particle size fractions.

Direct analysis of Antarctic krill by slurry sampling: determination of copper, iron, manganese and zinc by flame atomic absorption spectrometry

Alves,Flávia L.; Smichowski,Patricia; Farías,Silvia; Marrero,Julieta; Arruda,Marco A. Z.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/08/2000 EN
Relevância na Pesquisa
37.27%
Slurry sampling in combination with flame atomic absorption spectrometry was employed for the direct determination of four essential trace elements, namely Cu, Fe, Mn and Zn in Antarctic krill. The effect of instrumental operating conditions and slurry sampling preparation on the analytical signal was investigated. For the determination of Cu, Fe and Zn, samples were suspended in a solution containing 2 mol L-1 HNO3. In the case of Mn, 4 mol L-1 HNO3 was necessary for the preparation of the slurry. The precision between sample replicates was better than 5%. The method was applied to the direct determination of Cu, Fe, Mn and Zn in Antarctic krill samples using aqueous reference solutions to prepare the calibration curves. The results obtained were in good agreement with those achieved by FAAS and ICP-AES after microwave-assisted wet digestion of the krill samples. The detection limits were 4.5, 1.0, 4.9 and 8.4 mug L-1 for Cu, Zn, Mn and Fe, respectively.

Slurry sampling for Hg determination in sediments, sewage sludge and coal samples by cold vapor atomic absorption spectrometry

Ribeiro,Anderson S.; Vieira,Mariana A.; Curtius,Adilson J.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/12/2004 EN
Relevância na Pesquisa
37.4%
A simple and robust method for the determination of Hg in environmental samples by slurry sampling cold vapor generation atomic absorption spectrometry is proposed. After reducing the sample particles size to < 50 µm in an agate mortar, two procedures were used in the slurry preparation: either using 6.7% v/v nitric acid only or 10% v/v aqua regia plus 2% v/v hydrofluoric acid medium. Depending on the sample, the slurry concentrations varied from 3.3 to 23 mg mL-1. The mercury cold vapor generated directly from the acidified sample slurry was conducted to quartz T tube, placed in the atomizer of the spectrometer. Eight certified environmental materials were analyzed. By using the conventional calibration against aqueous standard solutions, excellent results were obtained when aqua regia plus hydrofluoric acid was used as the slurry medium. Sediment and coal samples from Santa Catarina, Brazil were also analyzed. The obtained limit of detection was 30 ng g-1. Simplicity, low cost and high efficiency are some of the qualities of the proposed method, making it adequate for routine analysis.

Slurry sampling for arsenic determination in sediments by hydride generation atomic absorption spectrometry

Torres,Daiane P.; Vieira,Mariana A.; Ribeiro,Anderson S.; Curtius,Adilson J.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2007 EN
Relevância na Pesquisa
37.27%
A simple and robust method for the determination of arsenic in sediments by hydride generation atomic absorption spectrometry (HG-AAS) using slurry sampling is proposed. Aqua regia (5% v/v) and hydrofluoric acid (1% v/v) were mixed with an aliquot of the sediment with particle size of 50 µm in an ultrasonic bath for 30 min. The slurry was allowed to stand for 48 h for an effective extraction of the analyte to the aqueous phase. The final volume of the slurry was made up with HCl 1 mol L-1. A NaBH4 solution stabilized with NaOH was used as reducing agent. The arsine was transported to the quartz T-tube heated at 900 °C for detection. Five certified reference materials of sediment were analyzed and the obtained concentrations were in good agreement with the certified values, according to the t-test for a 95% confidence level with RSD (relative standard deviation) lower than 13%. The limit of detection (LOD) in the sample was 0.6 µg g-1. The proposed procedure for arsenic determination in sediment is precise, accurate and adequate for the environmental samples routine analyses.

Determination of Metal Loading in Heterogeneous Catalyst by Slurry Sampling Flame Atomic Absorption Spectrometry

Garcia,Marco A. S.; Silvestre,Daniel M.; Nomura,Cassiana S.; Rossi,Liane M.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2015 EN
Relevância na Pesquisa
37.35%
Quantification of metal loading in supported catalysts is imperative; however, the analytical methods are usually time-consuming, expensive, and require sophisticated equipment and sample extraction with hazardous and corrosive strong acids. Herein, we report a new method for quantification of metal in supported catalysts using slurry sampling flame atomic absorption spectrometry. The slurry sampling method was used for determination of gold and the results were similar to those obtained with the traditional extraction method using aqua regia; however, it overcomes the main drawbacks associated with sample digestion by avoiding the use of concentrated toxic reagents, minimizing sample manipulation, and consequently, reducing the risks of contamination and the sample preparation time. Ultrasound radiation optimization associated with the solvent, mass of sample, concentration, and matrix effect in the slurry analysis allowed direct analysis by using the calibration in aqueous medium. The slurry sampling procedure could be applied to other catalysts with different supports and in bimetallic systems.

Oxidação úmida de fenóis com catalisadores de ferro suportado em argilominerais em reator de leito de lama (slurry); Phenol Wet oxidation on catalyst supported in clay minerals using a reactor with mechanical agitation (slurry)

Santiago Júnior, Aristides Felipe
Fonte: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Química; Pesquisa e Desenvolvimento de Tecnologias Regionais Publicador: Universidade Federal do Rio Grande do Norte; BR; UFRN; Programa de Pós-Graduação em Engenharia Química; Pesquisa e Desenvolvimento de Tecnologias Regionais
Tipo: Tese de Doutorado Formato: application/pdf
POR
Relevância na Pesquisa
37.27%
The wet oxidation of organic compounds with CO2 and H2O has been demonstrated to be an efficient technique for effluent treatment. This work focuses on the synthesis, characterization and catalytic performance of Fe-MnO2/CeO2, K-MnO2/CeO2/ palygorskite and Fe/ palygorskite toward the wet oxidative degradation of phenol. The experiments were conducted in a sludge bed reactor with controlled temperature, pressure and stirring speed and sampling of the liquid phase. Experiments were performed on the following operating conditions: temperature 130 ° C, pressure 20.4 atm, catalyst mass concentration of 5 g / L initial concentration of phenol and 0.5 g / L. The catalytic tests were performed in a slurry agitated reactor provided with temperature, pressure and agitation control and reactor liquid sampling. The influences of iron loaded on the support (0.3; 7 and 10%, m/m) and the initial pH of the reactant medium (3.1; 6.8; 8.7) were studied. The iron dispersion on the palygorskite, the phase purity and the elemental composition of the catalyst were evaluated by X-Ray Difraction (XRD), Scanning Electron Microscopy (SEM) and X-Ray Flourescence (XRF). The use of palygorskite as support to increase the surface area was confirmed by the B.E.T. surface results. The phenol degradation curves showed that the Fe3+ over palygorskite when compared with the other materials tested has the best performance toward the (Total Organic carbonic) TOC conversion. The decrease in alkalinity of the reaction medium also favors the conversion of TOC. The maximum conversion obtained from the TOC with the catalyst 3% Fe / palygorskite was around 95% for a reaction time of 60 minutes...

Efeitos da adição de nióbio no desempenho de ferros fundidos brancos de alto teor de cromo utilizados no bombeamento de polpa na mineração; Effects of Niobium Addition on Performance of White Cast Iron High Chromium Used in Slurry Pumping in Mining

Pereira, Leonardo Rodrigues
Fonte: Universidade Federal de Uberlândia Publicador: Universidade Federal de Uberlândia
Tipo: Dissertação
POR
Relevância na Pesquisa
37.27%
Durante o processo de beneficiamento da pirita e arsenopirita, minérios do qual se extrai o Ouro, são necessários equipamentos para a cominuição, classificação, concentração, entre outros, de um minério contendo elevados teores de óxidos altamente abrasivos, em especial, o óxido de Silício. Os componentes destes equipamentos apresentam, por esta razão, elevadas taxas de desgaste abrasivo e erosivo, gerando altos custos com reposição de peças. Como exemplo destes, citam-se: Ferramentas de penetração no solo, caçambas, barras de britadores, carcaça e rotores de bombas e revestimentos de moinhos. Os ferros fundidos brancos de alto Cromo (FFBAC) têm sido empregados na confecção de componentes de bombas de polpa. Neste trabalho foram identificados os mecanismos de desgaste atuantes nestes componentes, com o objetivo de selecionar os ensaios de desgaste mais adequados para a seleção de materiais usados na fabricação de rotores e revestimentos de bombas de polpa. Foram avaliadas ligas ferrosas com diferentes teores de Cromo e Molibdênio no estado temperado e revenido a 200ºC. São apresentados também, os resultados obtidos no desenvolvimento dos FFBAC contendo de 0,0 até 1,5% em peso de Nb. O comportamento foi analisado utilizando ensaios de laboratório feitos para reproduzir condições de campo. Foi utilizado um jato erosivo para avaliação do desgaste de componentes de bombas...

Effect of particle size on the flow properties of a South Australian coal-water slurry

Nguyen, Q.; Logos, C.
Fonte: Elsevier Science Publicador: Elsevier Science
Tipo: Artigo de Revista Científica
Publicado em //1996 EN
Relevância na Pesquisa
37.54%
The rheological behaviour of a low-rank coal-water slurry from Lochiel, South Australia, has been studied as a function of solids concentration, particle size and size distribution. Coal slurries consisting of particles finer than 45 μm suspended in water were found to exhibit a wide spectrum of flow behaviour ranging from Newtonian as low solids concentrations to shear-thinning and viscoplastic with a yield stress at higher concentrations. By adding a narrow-sized coarse coal fraction (208–279 μm) to the fine coal slurry, the flow characteristic of the slurry, at a fixed total solids concentrations, could be changed significantly with a substantial reduction in the slurry viscosity. An optimum coarse-to-fine particle ratio of 40:60 exists at which the slurry is Newtonian with a minimum viscosity of a about 5 times lower than the viscosity of a slurry containing only fine particles at the same solids concentration. A further reduction in the slurry viscosity of 50% was achieved by adding a second coarse coal particle (279–325 μm) to the bimodal slurry. The significant improvement in the rheological behaviour with changing the particle size distribution may be explained in terms of spatial rearrangement of the particles, and an apparent dilution effect. The results obtained in this study indicate that...

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

Fangueiro, D.; Fernandes, A.; Coutinho, J.; Moreira, N.; Trindade, H.
Fonte: Taylor & Francis Publicador: Taylor & Francis
Tipo: Artigo de Revista Científica
Publicado em //2009 ENG
Relevância na Pesquisa
37.35%
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 slurry

Molecular detection of hepatitis E virus in feces and slurry from swine farms, Rio Grande do Sul, Southern Brazil

Vasconcelos,J.; Soliman,M.C.; Staggemeier,R.; Heinzelmann,L.; Weidlich,L.; Cimirro,R.; Esteves,P.A.; Silva,A.D.; Spilki,F.R.
Fonte: Universidade Federal de Minas Gerais, Escola de Veterinária Publicador: Universidade Federal de Minas Gerais, Escola de Veterinária
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 EN
Relevância na Pesquisa
37.27%
Hepatitis E virus (HEV) is highly disseminated among swine herds worldwide. HEV is also a threat to public health, since particularly genotypes 3 and 4 may cause acute hepatitis in human beings. No previous studies were done on the occurrence of HEV in environmental samples in Rio Grande do Sul, Brazil. In the present study, reverse transcriptase-polymerase chain reaction (RT-PCR) was employed to detect the presence of HEV in swine feces and in effluents from slurry lagoons in farms located in the municipality of Teutônia, inside the area of swine husbandry in the state. Pooled fecal samples from the floor of pig barns from 9 wean-to-finish farms and liquid manure samples were collected from the slurry lagoons from 8 of these farms. From the pooled fecal samples, 8/9 were positive for the HEV ORF1 gene by RT-PCR; all the slurry lagoon samples were positive for HEV RNA (100%). The identity of the HEV ORF1 amplicons was confirmed by sequencing belonging to HEV genotype 3, which was previously shown to be circulating in South America.

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

Fangueiro, D.; Pereira, J.; Bichana, A.; Surgy, S.; Cabral, F.; Coutinho, J.
Fonte: Instituto Politécnico de Viseu Publicador: Instituto Politécnico de Viseu
Tipo: Artigo de Revista Científica
Publicado em /09/2015 ENG
Relevância na Pesquisa
37.48%
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.

Contribuição ao estudo da aderência de revestimentos de argamassa e chapiscos em substrato de concreto; Contribution to study of the bond strength of mortar renderings and slurry mortars on concrete substrate

Ruduit, Felipe Regert
Fonte: Universidade Federal do Rio Grande do Sul Publicador: Universidade Federal do Rio Grande do Sul
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
37.51%
A grande ocorrência de manifestações patológicas em revestimentos de argamassa associadas à falha de aderência a substratos de concreto cada vez mais chama a atenção do meio técnico, pois além de prejuízos às edificações, pode representar risco aos usuários, motivando diversos trabalhos sobre o assunto. Abordando o problema, a presente dissertação teve como tema a aderência de revestimentos de argamassa à substratos de concreto estrutural. Além da revisão bibliográfica, foram realizadas uma pesquisa em cima de dados de ensaios de resistência de aderência de revestimentos de argamassa em obras e edificações em uso e um programa experimental executado em laboratório. A pesquisa analisou dados obtidos de determinações de resistência de aderência à tração em revestimentos de argamassa de construções e edificações em uso em cidades do Rio Grande do Sul, principalmente na capital Porto Alegre. As informações foram coletadas de ensaios em analogia à NBR 13528 (ABNT, 1995) realizados pelo Departamento de Materiais de Construção Civil da Fundação de Ciência e Tecnologia (CIENTEC/RS) entre 1998 e 2009, totalizando 2616 resultados. Foram correlacionados resistências de aderência, regiões de ruptura e tipos de revestimentos e substratos com o objetivo de analisar as interações destes parâmetros com os resultados de aderência. Entre as constatações destacam-se a aderência dos revestimentos aplicados sobre substratos de concreto estrutural...

A full-scale study of treatment of pig slurry by composting: Kinetic changes in chemical and microbial properties

Ros Muñoz, Margarita Matilde; García Izquierdo, Carlos; Hernández Fernández Muñoz, María Teresa
Fonte: Elsevier Publicador: Elsevier
Tipo: Artículo Formato: 259768 bytes; application/pdf
ENG
Relevância na Pesquisa
37.27%
11 pages, 7 figures, 5 tables.; Since the indiscriminate disposal of pig slurry can cause not only air pollution and bad odours but also nutrient pollution of ground waters and superficial waters, composting is sometimes used as one environmentally acceptable method for recycling pig manure. The aim of this study was to evaluate the effect of composting pig slurry on its sanitation (evaluated by ecotoxicity assays and pathogen content determination), as well as to determine the effect of a carbon-rich bulking agent (wood shavings, WS) and the starting C/N ratio on the changes undergone by different chemical (volatile organic matter, C and N fractions) and microbiological (microbial biomass C, ATP, dehydrogenase activity, urease, protease, phosphatase, and β-glucosidase activities) parameters during composting. Pig slurry mixed with bulking agent (P + WS) and the solid faction separated from it, both with (PSF + WS) and without bulking agent (PSF), were composted for 13 weeks. Samples for analysis were taken from composting piles at the start of the process and at 3, 6, 9, and 13 weeks after the beginning of composting. The total organic carbon, water soluble C and ammonium content decreased with composting, while Kjeldahl N and nitrate content increased. The nitrification process in the PSF + WS pile was more intense than in the PSF or P + WS composting piles. The pathogen content decreased with composting...