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Obtaining high purity silica from rice hulls

SILVA JÚNIOR, José da; CUNHA, Carlo R. da; CARVALHO, Flávio L. S. de; RODRIGUES FILHO, Ubirajara P.; OLIVEIRA, Paulo R.; SILVA, Marcos A. Segatto
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
707.3493%
Many routes for extracting silica from rice hulls are based on direct calcining. These methods, though, often produce silica contaminated with inorganic impurities. This work presents the study of a strategy for obtaining silica from rice hulls with a purity level adequate for applications in electronics. The technique is based on two leaching steps, using respectively aqua regia and Piranha solutions, which extract the organic matrix and inorganic impurities. The material was characterized by Fourier-transform infrared spectroscopy (FTIR), powder x-ray diffraction (XRD), x-ray fluorescence (XRF), scanning electron microscopy (SEM), particle size analysis by laser diffraction (LPSA) and thermal analysis.

Análise da variação do índice de amorfismo da cinza de casca de arroz sobre a atividade pozolânica; Analysis of variation of the index of amorfization the ash of rice husk on the pozzolanic activity

Cordeiro, Luciana de Nazaré Pinheiro
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
482.35656%
Cinzas de casca de arroz são resíduos de comprovada eficiência como material pozolânico. No entanto, a variabilidades do material, decorrente das diferentes condições de geração impedem que o mesmo seja comercializado. Assim o presente trabalho tem como objetivo verificar a influência da variação do índice de amorfismo (IA) de cinzas de casca de arroz, sobre a atividade pozolânica deste material. As cinzas foram utilizadas em substituição parcial ao cimento. A metodologia de pesquisa foi dividida nas seguintes fases: (1) Coleta das cascas de arroz; (2) produção das cinzas de casca de arroz através da queima em diferentes temperaturas (500, 650, 800, 950 e 1100ºC) realizada em forno de laboratório. Fixou-se o tempo de residência do material (3 horas), a taxa de aquecimento (5°C/min), e resfriamento lento. Posteriormente utilizou-se a moagem das cinzas em diferentes tempos para que os diâmetros atendessem a finura apropriada para uma pozolana. (3) Em seguida o material gerado foi caracterizado através de ensaios químicos, físicos e mineralógicos; os demais materiais, tais como cimento e areia, também foram caracterizados, de forma que atendam as especificações normativas. (4) Com base nas análises dos resultados...

Otimização da hidrólise da casca de arroz (Oryza sativa) e avaliação da capacidade de bioconversão deste hidrolisado a etanol e xilitol por leveduras; Rice hull hydrolysis optimization and evaluation of this hydrolysate bioconversion to ethanol and xylitol by yeasts

Hickert, Lilian Raquel
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
381.39293%
Os resíduos lignocelulósicos agroindustriais, como a casca de arroz, são fontes abundantes e de baixo custo de celulose e hemicelulose, para produção biotecnológica de compostos de alto valor agregado, como os alcoóis, etanol e xilitol. O presente trabalho teve como objetivo otimizar a hidrólise ácida diluída da casca de arroz, utilizando como ferramenta o planejamento experimental, e ampliar os conhecimentos sobre a produção biotecnológica de etanol e xilitol, mediante o cultivo de microrganismos sobre esse hidrolisado. Um planejamento composto central 22 com três pontos centrais foi realizado abrangendo apenas as variáveis significativas para liberação de açúcares (temperatura e concentração de ácido). A máxima solubilização dos açúcares (70% de eficiência) foi obtida a 150ºC e 3 mmol H2SO4 g-1 sólido seco (SS), gerando cerca de 2,3 g L-1 de tóxicos totais (soma de inibidores ácido acético, furfural e hidroximetilfurfural). No entanto, é desejável que o hidrolisado contenha baixo teor de compostos tóxicos, já que estes podem comprometer a eficiência da fermentação. Sendo assim, a condição que empregou a temperatura de 129ºC e 4,4 mmol H2SO4 g-1 SS, apresentando 52% de eficiência na liberação de açúcares e apenas 0...

The Allium cepa bioassay to evaluate landfarming soil, before and after the addition of rice hulls to accelerate organic pollutants biodegradation

Souza, T. S.; Hencklein, F. A.; Angelis, D. F.; Goncalves, R. A.; Fontanetti, C. S.
Fonte: Academic Press Inc. Elsevier B.V. Publicador: Academic Press Inc. Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 1363-1368
ENG
Relevância na Pesquisa
507.3493%
Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Landfarming is a soil bioremediation technology practiced by oil refineries in order to reduce or eliminate hydrocarbons from petroleum sludge. The goal of the current study was to use Allium cepa bioassay to assess landfarming and landfarming with rice hulls amendment before and after hydrocarbons biodegradation assay in the laboratory. Three cytogenetic endpoints were used: mitotic and chromosome abnormalities (MCA), micronucleus (MN) and nuclear buds (NB). Landfarming presented 13.5 g/kg of total petroleum hydrocarbons (TPHs) and caused strong clastogenic and mutagenic effects (p<0.05) in A. cepa. After 108 days of biodegradation, the landfarming reached the rate of 26.30 mmol of CO(2) released, the concentration of TPHs decreased by 27% and there was significant reduction in MCA, MN and NB. Landfarming treated with rice hulls had the highest release of CO(2), 110.9 mmol, associated with a remarkable reduction in TPHs concentration, 59%, and had the highest decrease in MCA, MN and NB (p>0.05). Our findings showed that the use of rice hulls accelerated the biodegradation efficacy of landfarming and reduced their clastogenicity, indicating that supplementary treatments are important to improve the efficiency of bioremediation processes. (C) 2009 Published by Elsevier B.V.

High-fiber diets with reduced crude protein for commercial layers

Praes, M. F. F. M.; Junqueira, O. M.; Pereira, A. A.; Filardi, R. S.; Duarte, K. F.; Sgavioli, S.; Alva, J. C. R.; Domingues, C. H. F.
Fonte: Fundação APINCO de Ciência e Tecnologia Avícolas Publicador: Fundação APINCO de Ciência e Tecnologia Avícolas
Tipo: Artigo de Revista Científica Formato: 43-49
ENG
Relevância na Pesquisa
518.74047%
This study aimed at evaluating diets containing different fiber sources and two crude protein levels on the performance, egg quality, and nitrogen metabolism of commercial layers. In total, 392 48-wk-old Isa Brown layers were distributed according to a completely randomized experimental design in a 3x2+1 (control) factorial arrangement, resulting in seven treatments with seven replicates of eight birds each. Treatments consisted of three fiber feedstuffs (cottonseed hulls, soybean hulls, and rice hulls) and two dietary crude protein levels (12% and 16%). Cottonseed hulls associated with the high crude protein level (16%) resulted in the worst feed conversion ratio per dozen eggs. Diets with 16% crude protein resulted in the highest feed intake, egg production, egg weight, egg mass values, and improved feed conversion ratio (kg eggs/kg feed). The dietary inclusion of soybean hulls determined low yolk pigmentation, and of rice hulls, low egg specific gravity. The 16% crude protein diet with rice hulls promoted the best feed conversion ratio. Hens fed the reference diet presented higher egg mass and better feed conversion ratio per kg eggs and per dozen eggs. Hens fed the diets with low crude protein level (12%) had reduced nitrogen excretion...

Preparação e caracterização de carvão ativado quimicamente a partir da casca de arroz

Schettino Jr.,Miguel A.; Freitas,Jair C. C.; Cunha,Alfredo G.; Emmerich,Francisco G.; Soares,Ana B.; Silva,Paulo R. N.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2007 PT
Relevância na Pesquisa
487.22133%
This work consists in a study about the chemical activation of charred rice hulls using NaOH as the activation agent. The influence of the naturally-occurring silica was particularly evidenced. X-ray diffraction patterns showed the formation of sodium carbonate and silicates in the activated samples, whereas thermogravimetric curves revealed a strong reduction in the ash content of these samples after washing with water. Nitrogen adsorption data indicated a microporosity development only in the washed samples, with BET surface area values of 450 and 1380 m²/g achieved for the samples activated at 800 °C starting from the precursor with or without silica, respectively.

Obtaining high purity silica from rice hulls

Silva Júnior,José da; Cunha,Carlo R. da; Carvalho,Flávio L. S. de; Rodrigues Filho,Ubirajara P.; Oliveira,Paulo R.; Silva,Marcos A. Segatto
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2010 EN
Relevância na Pesquisa
707.3493%
Many routes for extracting silica from rice hulls are based on direct calcining. These methods, though, often produce silica contaminated with inorganic impurities. This work presents the study of a strategy for obtaining silica from rice hulls with a purity level adequate for applications in electronics. The technique is based on two leaching steps, using respectively aqua regia and Piranha solutions, which extract the organic matrix and inorganic impurities. The material was characterized by Fourier-transform infrared spectroscopy (FTIR), powder x-ray diffraction (XRD), x-ray fluorescence (XRF), scanning electron microscopy (SEM), particle size analysis by laser diffraction (LPSA) and thermal analysis.

Addition of alternative materials to ceramic slabs

Nara,E. O. B.; Moraes,J. A. R.; Freitas,A. M. V. de; Rediske,G.; Benitez,G. B.
Fonte: Associação Brasileira de Cerâmica Publicador: Associação Brasileira de Cerâmica
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/09/2014 EN
Relevância na Pesquisa
375.7486%
The construction market is very growing, leading to the emergence of new technologies and materials, and a growing need for sustainable products for the construction process, and the call for quality of life we present the description of a new option alternative materials for environments that require careful with the acoustics. The research covers the development and incorporation of new material in construction, with the potential acoustic, from tests and measurements with calibrated decibel meter called. We also used the ceramic tiles pre-molded, used for making floors or ceilings in buildings and homes. The methodology used for the development of this research was characterized as literature, exploratory, descriptive, qualitative and quantitative, alternative and affordable. How after the analysis results of the tests performed it can be seen that the incorporation of rice hulls of agglomerated to form ceramic tiles, possible reductions in noise levels on the order of 8 dB (A) than the traditional construction of the buildings, and then an excellent material. This research contributes to the construction so that presented a description of a new product developed from a conventional material, originating in agriculture, waste rice husk and its incorporation during the construction of buildings and home...

Rice hull-derived silica: applications in Portland cement and mullite whiskers

Souza,M.F. de; Batista,P.S.; Regiani,I.; Liborio,J.B.L.; Souza,D.P.F. de
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/04/2000 EN
Relevância na Pesquisa
591.45457%
Silica was extracted from rice hulls by three processing routes, starting with acid treatment followed by burning and milling. The amorphous white silica powder showed a surface area of 260 to 480 m²/g, purity above 99% and average particle size of 2.0 to 0.6 mm. This silica is suitable for the preparation of mullite whiskers employing the rare earth aluminosilicate glass technique. Due to its highly pozzolanic reaction, this prepared silica is used as an additive in high performance concrete.

Silica Derived from Burned Rice Hulls

Souza,M.F. de; Magalhães,W.L.E.; Persegil,M.C.
Fonte: ABM, ABC, ABPol Publicador: ABM, ABC, ABPol
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/10/2002 EN
Relevância na Pesquisa
599.68152%
Three new processes to obtain silica having high specific surface area from burned pre-treated rice hulls are presented and discussed. These procedures allow for the simultaneous recovery of biomass energy and the production of high quality silica at thermoelectric plants, without the risk of using corrosive substances in the burning process. The first method involves treatment of the hull with hot organic acid solutions before burning, the second with boiling water, both using an autoclave at temperatures close to150 °C, while the third method renders the hull fragile by treating it at 250 °C and reducing it to a fine powder before burning. The first two methods result in white amorphous silica that can show 500 m²/g of specific surface area. The third method, which does not remove the alkaline elements from the hull, produces an amorphous gray carbon-free powder whose specific surface area can be as high as 250 m²/g. An investigation of the specific surface area of the prepared silica indicates the alkaline elements are not mixed with silica in the hulls or combined as insoluble compounds. A comparison is made of these processes and the dissolution of silica by sodium hydroxide solutions is discussed.

High-fiber diets with reduced crude protein for commercial layers

Praes,MFFM; Junqueira,OM; Pereira,AA; Filardi,RS; Duarte,KF; Sgavioli,S; Alva,JCR; Domingues,CHF
Fonte: Fundação APINCO de Ciência e Tecnologia Avícolas Publicador: Fundação APINCO de Ciência e Tecnologia Avícolas
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2014 EN
Relevância na Pesquisa
518.74047%
This study aimed at evaluating diets containing different fiber sources and two crude protein levels on the performance, egg quality, and nitrogen metabolism of commercial layers. In total, 392 48-wk-old Isa Brown layers were distributed according to a completely randomized experimental design in a 3x2+1 (control) factorial arrangement, resulting in seven treatments with seven replicates of eight birds each. Treatments consisted of three fiber feedstuffs (cottonseed hulls, soybean hulls, and rice hulls) and two dietary crude protein levels (12% and 16%). Cottonseed hulls associated with the high crude protein level (16%) resulted in the worst feed conversion ratio per dozen eggs. Diets with 16% crude protein resulted in the highest feed intake, egg production, egg weight, egg mass values, and improved feed conversion ratio (kg eggs/kg feed). The dietary inclusion of soybean hulls determined low yolk pigmentation, and of rice hulls, low egg specific gravity. The 16% crude protein diet with rice hulls promoted the best feed conversion ratio. Hens fed the reference diet presented higher egg mass and better feed conversion ratio per kg eggs and per dozen eggs. Hens fed the diets with low crude protein level (12%) had reduced nitrogen excretion...

Activity of the Entomopathogenic Fungus Beauveria bassiana (Deuteromycota: Hyphomycetes) Against Three Coleopteran Pests of Stored Grain

Rice, William C.; Cogburn, Robert R.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
Relevância na Pesquisa
383.1108%
A Beauveria bassiana isolate from the rice water weevil, Lissorhoptrus oryzophilus Kuschel (Coleoptera: Curculionidae), was evaluated as a conidial powder against 3 coleopteran pests of stored grain: the rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae); the lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae); and the red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). Bioactivity of B. bassiana isolate 22292A was assessed on 3 types of food substrates (red flour beetle media, medium grain brown rice, and long grain rough rice) at 27°C and 60% RH. Adult mortality was 80–100% at the higher dosage levels for all insects tested on all media types at 21 d after treatment. Emergence of adult progeny on brown and rough rice was reduced by 83–99% at the 2 highest dosage level. The abrasive nature of rice hulls on the rough rice may contribute to the accelerated mortality seen on this medium.

Fate of Malathion and Chlorpyrifos Methyl in Rough Rice and Milling Fractions Before and After Parboiling and Cooking

Cogburn, Robert R.; Simonaitis, R. A.; Webb, B. D.
Fonte: Oxford University Press Publicador: Oxford University Press
Tipo: Artigo de Revista Científica Formato: text/html
EN
Relevância na Pesquisa
402.5486%
Long-grain rough rice treated with malathion (14 ppm) or chlorpyrifos methyl (Reldan) (6 ppm or 12 ppm) was sampled after 1, 6, and 12 wk. Samples from each treatment were processed raw or were parboiled with fresh steeping water, once-used, and twice-used steeping water. Three replicates of rough rice and of each milling fraction were preserved, and three of milled rice were cooked. Chemical residues were measured on rough rice, hulls, brown rice, bran, milled rice, and cooked rice. Parboiling reduced residues on rough rice and hulls but tended to increase residues in the other fractions. Residues of Reldan in bran were substantially increased by parboiling. Doubling the amount of Reldan applied to rough rice approximately doubled the residues found in the milling fractions. Small amounts of the protectants survived all processing including cooking. Residues of malathion in cooked rice averaged about 0.016 ppm in nonparboiled and 0.013 ppm in parboiled rice. Residues of Reldan in cooked rice was commensurate with the amount applied to rough rice. When applied to rough rice at 6 ppm, residues of Reldan in cooked rice averaged 0.05 ppm in nonparboiled rice and 0.065 ppm in parboiled rice. When applied to rough rice at 12 ppm, residues in cooked rice averaged 0.053 ppm in nonparboiled rice and 0.15 ppm in parboiled rice. Legal tolerances were not exceeded in any milling fraction. Reuse of the steeping water had little or no effect on residues.

Diferentes recipientes e substratos na produção de mudas de cafeeiros; Containers and substrates in seedlings production of coffee tree

Fonte: Editora da Universidade Federal de Lavras Publicador: Editora da Universidade Federal de Lavras
Tipo: Artigo de Revista Científica
PT_BR
Relevância na Pesquisa
487.22133%
With the objective of evaluating the effects of different recipients and substrates on the production of coffee tree seedlings (Coffea arabica L.), an experiment was carried out at the Coffee Sector of the Universidade Federal de Lavras, MG - UFLA, in the period of September 2003 to January 2004. The experiment was arranged in a randomized block design using a 3x3 factorial scheme. The recipients used were rigid polyethylene tubettes /50 mL capacity; tubettes /120 mL; and 10x20cm polyethylene bags with approximate capacity of 700 mL. The substrates used were alternative substrate, composed of 65% charred rice hulls + 35% commercial substrate; Plantmax HT®; and standard substrate, composed of 70% soil + 30% (sieved) cattle manure. The results obtained brought us to the conclusion that the type of recipient and substrate, in fact, significantly influence the development of coffee tree seedlings; and the recipients of larger volume (polyethylene bags and 120mL tubettes) filled with alternative and commercial substrates provide seedlings with improved growth rate.

Sil??cio oriundo da cinza de casca de arroz carbonizada como promotor do rendimento e da qualidade fisiol??gica de sementes de soja; Silicon derived ash rice hulls as a promoter yield and seed quality of soybean

OLIVEIRA, Sandro de
Fonte: Universidade Federal de Pelotas; Agronomia; Programa de P??s-gradua????o em Ci??ncia e Tecnologia de Sementes; UFPel; BR Publicador: Universidade Federal de Pelotas; Agronomia; Programa de P??s-gradua????o em Ci??ncia e Tecnologia de Sementes; UFPel; BR
Tipo: Dissertação Formato: application/pdf
POR
Relevância na Pesquisa
378.35367%
Soybean is an important crop for Brazilian agriculture. The use of quality seeds, as well as appropriate plant nutrition and the adoption of modern techniques of cultivation are fundamental to the success of the crop. The use of silicon is a clean technology to environmentally and in addition may offer several benefits to plants. The aims of this study were to evaluate the effect of application of silicon from carbonized rice husk through the seed treatment and from soil in two soybean cultivars, and evaluate physiological quality of treated seeds, morphologic characteristics, yield components, yield and physiological quality of the seed produced. Four experiments were performed in randomized complete block design, using carbonized rice husk as a source of silicon. The experiments differ as the application form of carbonized rice husk and five doses of silicon were applied using seed coating (0, 30, 60, 90, and 120 g 100 kg seed-1) and throught soil were used the following doses (0, 1, 2, 3, and 4 tons ha-1). The soybean cultivars used in this study were (BMX Turbo RR and NA 5909 RR). Physiological quality of treated seeds and seed produced were evaluated by germination test and vigor tests. Morphological characteristics and yield components were also analyzed. The results showed that the application rates of silicon in the soil increases productivity...

Cambodia

World Bank Group
Fonte: Washington, DC Publicador: Washington, DC
Tipo: Relatório
EN_US
Relevância na Pesquisa
386.1689%
The use of quality seed is a major component of increased yields in crop production. Quality seed and seed programs in a country does not emerge by happenstance; it is created by a combination of many factors that include variety development, seed production, quality control, processing, marketing, and governmental oversight. As the seed sector in a country matures, each of these factors becomes more important and plays a more important role in the growth of the agricultural sector. The seed program in Cambodia is interestingly different from that in many other developing countries. Even without a true seed program in Cambodia, farmers understand the need to plant quality seed to increase crop yields. When structuring this growing seed industry, it is important to look at current practices and to incorporate these practices into programs. Since a major thrust of the seed program in Cambodia involves rice, it is important to consider its role in the average Cambodian’s life. Cambodia’s climate must also be accounted for in any decisions regarding seed. Its heat and humidity causes rapid deterioration of seed viability and germination in rice and other seeds in both the growth and storage phases. CARDI research has shown that the level of rice germination falls below 80-85 percent within 6-8 months after harvest; this means that seed must be planted during the growing season following harvest. Therefore...

Obtenção de sílicas mesoporosas altamente ordenadas a partir das cinzas da casca de arroz e do bagaço de cana-de-açúcar; Obtaining highly ordered mesoporous silica from rice husk and sugar cane bagasse ashes

Oliveira, Juliana Ferreira de
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 11/12/2014 PT
Relevância na Pesquisa
480.1184%
O presente trabalho propõe o uso das cinzas de dois resíduos agroindustriais - casca de arroz e bagaço de cana-de-açúcar - como fonte de sílica (SiO2) para a síntese de sílicas mesoporosas altamente ordenadas. Esta aplicação, além de agregar valor aos resíduos, busca uma alternativa ao tetraetil ortossicato, uma fonte de sílica dispendiosa, cuja obtenção resulta em danos ambientais. Amostras de cascas arroz de quatro procedências distintas foram caracterizadas por termogravimetria/ termogravimetria derivada (TG/DTG), calorimetria exploratória diferencial (DSC) e análise elementar de CHN. Com base nestes resultados, duas amostras foram selecionadas para obtenção de sílica. Outras duas amostras de bagaço de cana-de-açúcar de origens diferentes foram também caracterizadas por esta metodologia. Para melhor entender as etapas de degradação térmica da matéria orgânica, os resultados de TG/DTG foram associados aos de FT-IR e um estudo cinético por TG foi realizado. Diferentes tratamentos em meio ácido, com o objetivo de remover impurezas e reduzir o tempo necessário para calcinação dos materiais, foram realizados. O método escolhido para cada um dos materiais foi definido a partir dos testes e por avaliação de resultados de TG/DTG. As cinzas obtidas após calcinação em mufla dos materiais com e sem tratamento ácido prévio...

Efeito de substrato artificial no enraizamento de estacas de calanchoe (Kalanchoe x blossfeldiana cv. singapur, crassulaceae); Artificial substract effect on the rooting of calanchoe (Kalanchoe x blossfeldiana cv. singapur, crassulaceae) cuttings

Gonçalves, A.L.; Minami, K.
Fonte: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz Publicador: Universidade de São Paulo. Escola Superior de Agricultura Luiz de Queiroz
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; ; ; ; ; Formato: application/pdf
Publicado em 01/08/1994 POR
Relevância na Pesquisa
391.45457%
Ten different artificial mixtures were studied as rooting media for Kalanchoe x blossfeldiana cv. Singapur cuttings. They were: vermiculite + toasted rice hulls (1:1, 2:1, 3:1); vermiculite + Oliver filter cake (1:1, 2:1, 3:1); vermiculite + peat (1:1, 2:1, 3:1); and vermiculite + pine bark (commercial mixture). The best results were observed for vermiculite + Oliver filter cake (1:1, 2:1, 3:1), vermiculite + toasted rice hulls (3:1) and vermiculite + peat (3:1). The worst results were observed with vermiculite + pine bark and vermiculite + peat (1:1).; Dez misturas artificiais foram estudadas para avaliar o efeito sobre o enraizamento de estacas apicais de Kalanchoe x blossfeldiana cv. Singapur, da família Crassulaceae. Essas misturas foram as seguintes: vermiculita + casca de arroz tostada nas proporções 1:1, 2:1 e 3:1; vermiculita + torta de filtro Oliver nas proporções 1:1, 2:1 e 3:1; vermiculita + turfa da região de Atibaia-SP, nas proporções 1:l, 2:le3:l; vermiculita + casca de pinheiro (mistura comercial). Os melhores resultados foram obtidos com a mistura vermiculita + torta de filtro Oliver em todas as proporções, vermiculita + casca de arroz tostada 3:1 e vermiculita + turfa 3:1. Os piores desempenhos foram os das misturas vermiculita + casca de pinheiro e vermiculita + turfa 1:1.

Renewable substrates in the seedling production of Mimosa scabrella.; SUBSTRATOS RENOVÁVEIS PARA PRODUÇÃO DE MUDAS DE Mimosa scabrella

Kratz, Dagma; Doutoranda, UFPR, Curitiba, PR, Brasil; Nogueira, Antonio Carlos; UFPR; Wendling, Ivar; Embrapa Florestas; de Souza, Paulo Vitor Dutra; UFRGS
Fonte: FUPEF DO PARANÁ Publicador: FUPEF DO PARANÁ
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Artigo Avaliado pelos Pares Formato: application/pdf
Publicado em 19/11/2014 POR
Relevância na Pesquisa
522.45574%
Objetivou-se neste estudo avaliar a viabilidade técnica de substratos renováveis à base de fibra de coco, casca de arroz carbonizada em diferentes granulometrias, biossólido e casca de pínus semidecomposta para a produção de mudas de Mimosa scabrella. Para tanto, foram formulados 41 tratamentos, contendo como testemunha substrato comercial à base de casca de pínus, os quais tiveram suas propriedades físicas e químicas avaliadas. Realizou-se semeadura direta em tubetes de 55 cm³, permanecendo por 120 dias em estufa de vidro e 30 dias na área de pleno sol. Observou-se que o substrato comercial à base de casca de pínus e substratos com diferentes combinações de casca de arroz carbonizada e fibra de coco apresentaram-se viáveis para produção de mudas de M. scabrella, enquanto que o componente biossólido mostrou-se inviável. O peneiramento da casca de arroz não se justifica, quando comparado com a casca de arroz carbonizada na sua forma íntegra. Quanto menor a agregação do substrato às raízes, maior a facilidade de retirada das mudas dos tubetes. A densidade, matéria orgânica, pH, condutividade elétrica, salinidade e concentração de magnésio e fósforo influenciaram no crescimento das mudas.Palavras-chave:  Bracatinga; biossólido; casca de arroz carbonizada; fibra de coco; propriedades físicas. AbstractRenewable substrates in the seedling production of Mimosa scabrella. The objective of this study was to evaluate the technical feasibility of renewable-based substrates coconut fiber...

PERFORMANCE OF TWO TYPES OF CEMENT IN PRODUCTION OF CEMENT BONDED WOOD PANELS COMBINED WITH RICE HULL; PERFORMANCE OF TWO TYPES OF CEMENT IN PRODUCTION OF CEMENT BONDED WOOD PANELS COMBINED WITH RICE HULL

Azambuja, Rafael da Rosa; UFPR; Lilge, Daniela Silva; UNIPAMPA; Santini, Elio José; UFSM; Haselein, Clovis Roberto; UFSM
Fonte: FUPEF DO PARANÁ Publicador: FUPEF DO PARANÁ
Tipo: info:eu-repo/semantics/article; info:eu-repo/semantics/publishedVersion; Artigo Avaliado pelos Pares Formato: application/pdf
Publicado em 09/04/2014 POR
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AbstractThe objective of this study was to evaluate the performance of two types of cement in the manufacturing of cement bonded wood panels with addition of rice hull. Sealers used were cement V-ARI (CP V) and cement Portland IV, pozzolanic (CP IV). Proportions adopted in the composition of panels were 0, 50 and 100 % rice hulls combined with 100, 50 and 0% of wood particles. Species used in this study were Eucalyptus grandis and Pinus elliottii. Parameters considered to evaluate panels were the mechanical properties. CP IV did not cure with the addition of pine particles in any proportion. The values of modulus of rupture (MOR) were higher with CP IV, but with the addition of rice hulls they decreased. CP V shoved higher internal bond strength in all proportions studied. Addition of rice hulls decreased all the mechanical properties studied in this work, therefore its use in cement bonded wood panels must be controlled, larger quantities than 50% of total vegetal mass weight are not recommended. Using Bison process as a reference, CP IV presented the necessary requirements to be used in cement bonded wood panels.Keywords: Eucalyptus grandis; CP IV; CP V-ARI; agricultural waste.; AbstractPERFORMANCE OF TWO TYPES OF CEMENT IN PRODUCTION OF CEMENT BONDED WOOD PANELS COMBINED WITH RICE HULLThe objective of this study was to evaluate the performance of two types of cement in the manufacturing of cement bonded wood panels with addition of rice hull. Sealers used were cement V-ARI (CP V) and cement Portland IV...