oalib

Publish in OALib Journal

ISSN: 2333-9721

APC: Only $99

Submit

Any time

2019 ( 55 )

2018 ( 99 )

2017 ( 94 )

2016 ( 103 )

Custom range...

Search Results: 1 - 10 of 65120 matches for " Machado Carlos Cardoso "
All listed articles are free for downloading (OA Articles)
Page 1 /65120
Display every page Item
Comportamento geotécnico de misturas granulometricas de solo-grits
Machado, Carlos Cardoso;Portugal, Carla Ribeiro Machado e;
Revista árvore , 2012, DOI: 10.1590/S0100-67622012000300014
Abstract: the objective of this experiment was to analyze the influence of size distribution of the industrial waste, named grits, on the optimum compaction parameters, mechanical strength and expansion of two typical soils in the north forest zone of minas gerais state, brazil, for forest road applications. contents of waste used in the mixtures were 4, 8, 12, 16, 20, 24 and 28 % regarding soils dry mass, working with compacting units of intermediary and modified proctor trials. the assessed waste fractions were those equivalent to clay and silt (? < 0.074 mm), sand (0.074 < ? < 2 mm), and gravel (2 mm < ? < 76 mm), considering the size scale adopted by dnit (dnit, 1996). bearing capacity and expansion of soils and mixtures were evaluated by using the cbr test. results showed that the fine fraction of the grits is the one which contributes the most for gains in the mechanical strength, evidencing its importance in the reactivity of the mixtures, and gravel is that influences the least the gain of bearing capacity of the soils.
PRODUTIVIDADE E CUSTOS DO PROCESSADOR TRABALHANDO EM POVOAMENTOS DE Eucalyptus grandis Hill ex Maiden
Bernardo Carlos Tarnowski,Paulo Renato Schneider,Carlos Cardoso Machado
Ciência Florestal , 1999,
Abstract: No presente trabalho foi realizado um estudo de tempos com o objetivo de ajustar equa es para estimar o tempo das atividades, a produtividade, o custo operacional e da produ o do processador utilizado em um sistema de colheita de madeira de povoamentos de Eucalyptus grandis Hill ex Maiden, em topografia plana, no Estado da Bahia. O ciclo operacional do processador consistiu no tempo gasto para processar uma árvore e foi dividido em etapas as quais foram cronometradas, usando a metodologia dos tempos individuais. A unidade amostral foi constituída do ciclo operacional da máquina. A análise estatística baseou-se em estudo de regress o, sendo utilizado o procedimento de modelagem de regress o "stepwise". Com as equa es ajustadas, foi possível estimar a produtividade da máquina em fun o do diametro das árvores. Nas condi es do estudo, considerando uma eficiência operacional de 70%, a produtividade do processador foi de 25,8 m3cc/h, o custo operacional 47,90 US$/h e o custo de produ o de 1,86 US$/m3cc. Com base nos resultados obtidos, pode-se concluir que: o tempo de processamento das árvores varia diretamente com o aumento do diametro; o tempo de prepara o, ao contrário do tempo de processamento, possui uma baixa correla o com o diametro das árvores; a produtividade do processador é diretamente proporcional ao aumento do diametro das árvores, quando expressa em volume, e inversamente proporcional, quando expressa em número de árvores; o custo por metro cúbico de madeira processada com processador, varia numa rela o inversa ao aumento do diametro; do custo operacional do processador, o custo fixo é o de maior propor o, seguido do custo variável, administrativo e da m o-de-obra; e, o custo de produ o do processador diminui em forma exponencial com o aumento do diametro das árvores.
Comportamento resiliente de um solo argiloso da regi o de Vi osa-MG no estado natural e estabilizado com cimento e alcatr o fracionado
Sant'Anna Giovanni Levi,Machado Carlos Cardoso,Carvalho Carlos Alexandre Braz de,Lima Dario Cardoso de
Revista árvore , 2003,
Abstract: A importancia do estudo das características resilientes dos solos e das misturas estabilizadas quimicamente justifica-se pela necessidade de conhecer o seu comportamento mecanico, sob a a o de cargas repetidas e transientes, quando constituintes do pavimento de estradas florestais. O método tradicional de determina o do módulo de resiliência, em laboratório, requer o emprego de um equipamento triaxial de cargas repetidas, que é relativamente complexo e caro, o que leva à necessidade de se desenvolver métodos mais simples para determina o do módulo de resiliência. Assim, buscou-se com este trabalho determinar o módulo de resiliência de um solo argiloso comum na regi o de Vi osa-MG em seu estado natural e quando estabilizado com cimento e alcatr o, como também propor correla es empíricas entre este e outros parametros geotécnicos de fácil obten o em laboratório.
Módulo de resiliência de um solo arenoso e de suas misturas com alcatr o fracionado e cal
Sant'Anna Giovani Levi,Machado Carlos Cardoso,Carvalho Carlos Alexandre Braz de,Lima Dario Cardoso de
Revista árvore , 2003,
Abstract: O conhecimento do módulo de resiliência dos solos de subleito e dos materiais que comp em as camadas de pavimentos rodoviários é obrigatório para uma análise eficiente de seu comportamento estrutural como um todo. Devido à importancia dos materiais granulares como constituintes de camadas de pavimentos rodoviários flexíveis, tem-se evidenciado maior interesse em abordar a sua resposta resiliente e de misturas estabilizadas quimicamente obtidas a partir destes, procurando conhecer o seu comportamento mecanico, sob a a o de cargas repetidas, quando constituintes do pavimento de estradas florestais. Buscou-se, com a realiza o deste trabalho, identificar o módulo de resiliência de um solo arenoso comum na regi o de Vi osa-MG, em seu estado natural e quando estabilizado com cal e alcatr o, e propor correla es empíricas entre este e outros parametros geotécnicos de fácil obten o em laboratório.
Influência da imers?o em água na resistência mecanica de misturas solo-grits compactadas e curadas com vistas a aplica??es em estradas florestais
Pereira, Reginaldo Sérgio;Machado, Carlos Cardoso;Lima, Dario Cardoso de;Carvalho, Carlos Alexandre Braz de;Danuse Machado, Pires;
Revista árvore , 2007, DOI: 10.1590/S0100-67622007000300013
Abstract: this paper address the influence of water submersion on mechanical strength parameters of soil-grits specimens. two residual soils, predominantly clayey and sandy soils from the city of vi?osa, located in the state of minas gerais, "zona da mata norte", brazil, and waste from cellulose industry were used in the study. the laboratory testing program consisted of cbr (california bearing ratio) and ucs (unconfined compression strength) of specimens prepared with waste contents ranging from 4 to 28 %, compacted at the intermediate and modified compaction efforts, and cured during 0, 7 and 28 days. laboratory tests were performed as follow: (i) cbr: tests were performed following the standard procedure, i.e. after 4 days water submersion before specimen penetration, and without submersion; and (ii) ucs: tests were performed following the brazilian standard procedure, i.e. after 4 hours specimen submersion before testing, and without water submersion. the laboratory testing program data support that water submersion significantly influenced the tested mechanical strength parameters, which were dependent of the type of assay and soil, percentage of grits waste, compaction effort and cure.
Uso do resíduo industrial grits em pavimentos de estradas florestais: influência do período de cura na resistência mecanica e expans?o de misturas solo-grits compactadas
Pereira, Reginaldo Sérgio;Machado, Carlos Cardoso;Lima, Dario Cardoso de;Carvalho, Carlos Alexandre Braz de;Pires, Danuse Gouvea Machado;
Revista árvore , 2006, DOI: 10.1590/S0100-67622006000500013
Abstract: this paper addresses the influence of stabilizer content, compaction effort and curing time on the mechanical strength and swelling of two soils from the "zona da mata norte" region, state of minas gerais, brazil. two residual gneiss soils from the municipality of vi?osa, brazil, silt-sand-clay and silt-clay-sandy soils named soils 1 and 2, respectively, were used in this study. industrial grits provided by celulose nipo brasileira - cenibra was used as stabilizer, with contents ranging from 4 to 28 % regarding soil dry mass. specimens of soil-grits mixtures were compacted at the intermediate proctor compaction effort and curing times of 0, 7, 28 and 90 days. mechanical strength was evaluated as follows: california bearing ratio (cbr), unconfined compression strength (ucs) and indirect tensile strength (its). data from the laboratory-testing program supported that all parameters affected mixture mechanical strength significantly, and the mechanical behavior of soil 1-grits mixtures were also influenced by sodium content of grits.
Caracteriza??o tecnológica de misturas solo-grits para pavimentos de estradas florestais: influência do tratamento térmico do grits na resistência mecanica das misturas
Machado, Carlos Cardoso;Pereira, Reginaldo Sérgio;Lima, Dario Cardoso de;Carvalho, Carlos Alexandre Braz de;Pires, Danuse Machado;
Revista árvore , 2007, DOI: 10.1590/S0100-67622007000300014
Abstract: the objective of this paper was to analyze the influence of grits thermal treatment on the mechanical strength of soil-grits mixtures. the laboratory testing program included: (i) two residual gneiss soils from the zona da mata, northern minas gerais; (ii) waste from the cellulose industry, namely grits, composed by non-hydrated lime and sand, among others by-products; (iii) grits samples submitted to thermal treatment in a muffle at the temperatures of 600, 700, 800 and 900 oc before soils-grits specimens preparation; (iv) soils-grits specimens containing 24% of treated grits in relation to soil dry unit compacted at the intermediate and modified proctor compaction test, and cured during 7 and 28 days in a moist room at the temperature of 22 oc and relative humidity close to 100 %; and (iv) complete immersion of cured specimens in water (4 hours) before testing for compressive strength using the unconfined compression test. data from the laboratory testing program support that: (i) thermal treatment produced more reactive grits samples; and (ii) best soils-grits mechanical responses were associated to grits treatment temperatures of 800 and 900 oc for soil 1, and to 800 oc for soil 2.
Compacta??o de misturas solo-grits para emprego em estradas florestais: influência do tempo decorrido entre mistura e compacta??o na resistência mecanica
Pereira, Reginaldo Sérgio;Machado, Carlos Cardoso;Lima, Dario Cardoso de;
Revista árvore , 2006, DOI: 10.1590/S0100-67622006000300012
Abstract: many factors affect the construction and performance of chemically stabilized highway pavement soil layers, especially mixture homogenization, time between mixture and compaction, and selection of compaction equipment. regarding forest road application, this paper addresses the influence of time between mixture and compaction (tmc) on compaction optimum parameters and on mechanical strength of mixtures of two typical soils from the region `zona da mata norte', state of minas gerais, and grits, a waste from the cellulose industry, as well as the influence of grits sampling on the mechanical strength of soil 2-grits mixtures. california bearing ratio (cbr) data from laboratory specimens compacted at the intermediate proctor compaction effort were used throughout the study. the laboratory testing data supported that time between mixture and compaction significantly affected the mechanical strength of the tested soil mixtures. regarding soil samples and from a practical point of view, it is recommended that such studies should be always performed on regional basis. it was observed significant influence of grits sampling on the mechanical strength of soil 2-grits mixtures.
Influência do tratamento térmico do resíduo sólido industrial (Grits) na resistência mecanica de um latossolo para pavimentos de estradas florestais
Machado, Carlos Cardoso;Pereira, Reginaldo Sérgio;Pires, José Maurício Machado;
Revista árvore , 2003, DOI: 10.1590/S0100-67622003000400015
Abstract: road engineering studies involving chemical stabilization of soils deserve special recognition mainly those directed to lowering the costs of forest engineering roads. this work focuses on soil stabilization of a characteristic latosol from vi?osa, minas gerais, brazil, herein named eta, using a residue from paper and cellulose industry production, herein called grits. grits content of 10% related to soil dry weight was used throughout the study after residue thermal treatment using a furnace at 200, 300, 400, 500 and 600 oc. geotechnical standard parameters from compaction and unconfined compression tests were used to evaluate the effect of thermal treatment on the mechanical response of soil-grits mixtures. unconfined compression testing data show that grits is a promising soil stabilizer, mainly after thermal treatment at 600 oc.
Potencial poluidor de resíduo sólido da Samarco Minera??o: estudo de caso da barragem de Germano
Pires, José Maurício Machado;Lena, Jorge Carvalho de;Machado, Carlos Cardoso;Pereira, Reginaldo Sérgio;
Revista árvore , 2003, DOI: 10.1590/S0100-67622003000300017
Abstract: samples of solid waste from the germano dam of samarco minera??o s.a were studied. this dam is located in the county of mariana and it is mainly used to retain the waste resulting from the iron ore treatment at the germano plant. the waste was classified according to the abnt norms 10004, 10005, 10006 and 10007. as class iii (inert) which was shown to be capable to retain heavy metals as well as chromium.
Page 1 /65120
Display every page Item


Home
Copyright © 2008-2017 Open Access Library. All rights reserved.