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Registro Completo |
Biblioteca(s): |
Embrapa Meio Norte / UEP-Parnaíba. |
Data corrente: |
25/06/1996 |
Data da última atualização: |
05/01/2012 |
Autoria: |
SILVA, E. M. da. |
Título: |
Analysis of furrow irrigation uniformity as affected by furruw spacing. |
Ano de publicação: |
1990 |
Fonte/Imprenta: |
Arizona: The University of Arizona, 1990. |
Volume: |
2 v. |
Páginas: |
449p. |
Idioma: |
Inglês |
Notas: |
Tese Doutorado. |
Conteúdo: |
This research examines the effects of furrow spacing on irrigation uniformity and efficiency. Laboratory and field experiments were conducted to obtain information on soil physical characteristics, furrow infiltration and water advance data in order to validate the theoretical results. A furrow infiltration model based on Richards' equation and a finite element technique is developed and used to predict infiltrated depths in the transverse and longitudinal directions relative to the furrow centerline and furrow inlet, respectively. The model predicted measured furrow infiltration in the field from the third irrigation but failed to do so for the first and second irrigations. Simulations of furrow irrigation in a hypothetical soil with various furrow spacingsshowed that cumulative infiltration is not affected by furrow spacing until the lateral wetting front reaches the imaginary vertical boundary located midway between two furrows. An analysis of uniformity and efficiency from predicted water distribution profiles from field irrigated furrows are conclusive in that the use of longitudinal water distribution profile alone is not enough to assess the performance of furrow irrigation. The transverse distribution of infiltrated depths which is a function of furrow spacing must be included in the analysis. |
Palavras-Chave: |
Uniformidade. |
Thesagro: |
Irrigação por Sulco. |
Thesaurus Nal: |
furrow irrigation. |
Categoria do assunto: |
-- |
Marc: |
LEADER 01819nam a2200181 a 4500 001 1077587 005 2012-01-05 008 1990 bl uuuu m 00u1 u #d 100 1 $aSILVA, E. M. da 245 $aAnalysis of furrow irrigation uniformity as affected by furruw spacing. 260 $aArizona: The University of Arizona$c1990 300 $a449p. 2 v. 490 $v2 v. 500 $aTese Doutorado. 520 $aThis research examines the effects of furrow spacing on irrigation uniformity and efficiency. Laboratory and field experiments were conducted to obtain information on soil physical characteristics, furrow infiltration and water advance data in order to validate the theoretical results. A furrow infiltration model based on Richards' equation and a finite element technique is developed and used to predict infiltrated depths in the transverse and longitudinal directions relative to the furrow centerline and furrow inlet, respectively. The model predicted measured furrow infiltration in the field from the third irrigation but failed to do so for the first and second irrigations. Simulations of furrow irrigation in a hypothetical soil with various furrow spacingsshowed that cumulative infiltration is not affected by furrow spacing until the lateral wetting front reaches the imaginary vertical boundary located midway between two furrows. An analysis of uniformity and efficiency from predicted water distribution profiles from field irrigated furrows are conclusive in that the use of longitudinal water distribution profile alone is not enough to assess the performance of furrow irrigation. The transverse distribution of infiltrated depths which is a function of furrow spacing must be included in the analysis. 650 $afurrow irrigation 650 $aIrrigação por Sulco 653 $aUniformidade
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Registro Completo
Biblioteca(s): |
Embrapa Florestas. |
Data corrente: |
23/08/2019 |
Data da última atualização: |
03/10/2019 |
Tipo da produção científica: |
Artigo em Periódico Indexado |
Circulação/Nível: |
A - 1 |
Autoria: |
CADEMARTORI, P. H. G. de; ARTNER, M. A.; FREITAS, R. A. de; MAGALHAES, W. L. E. |
Afiliação: |
Pedro Henrique Gonzalez de Cademartori, UFPR; Mirela Angelita Artner, UFPR; Rilton Alves de Freitas, UFPR; WASHINGTON LUIZ ESTEVES MAGALHAES, CNPF. |
Título: |
Alumina nanoparticles as formaldehyde scavenger for urea-formaldehyde resin: rheological and in-situ cure performance. |
Ano de publicação: |
2019 |
Fonte/Imprenta: |
Composites Part B, v. 176, article 107281, Nov. 2019. 9 p. |
DOI: |
10.1016/j.compositesb.2019.107281 |
Idioma: |
Inglês |
Conteúdo: |
Formaldehyde emission in the environment from thermosetting resins, like urea-formaldehyde (UF), is one of the most negative aspects of wood-based composite panels. UF resins with low or zero formaldehyde emission and keeping or improving their remarkable properties have been designed by different approaches, with special attention to organic and inorganic nanofillers. Although formaldehyde emission can be mitigated, controlling of rheology kinetics, curing and thermal stability are essential to avoid restrictions for practical applications. Here, we investigated the incorporation of small percentages of Al2O3 nanoparticles into UF resin regarding its rheology, thermodynamic mechanics, thermal kinetics and morphology. Changes on formaldehyde emission was determined by desiccator method and qualitatively illustrated by thermogravimetry-mass spectrometry analysis. The Al2O3 incorporation without significant agglomerations changed the viscosity of UF resin, presenting a shear thinning behavior, especially for higher quantity of nanoparticles. Likewise, analysis of thermodynamic mechanisms shows Al2O3 as an effective additive for UF resin without changing important curing parameters like vitrification point and gel temperature. Al2O3 nanoparticles are also effective to reduce the formaldehyde emission during the UF resin cure reactions at high temperatures and up to 14% in MDF composite panels at environmental temperatures. |
Palavras-Chave: |
Alumina; Cure behavior; Formaldeído; Nanopartícula; Reologia; Thermosetting resin. |
Thesaurus NAL: |
Nanoparticles; Rheology. |
Categoria do assunto: |
X Pesquisa, Tecnologia e Engenharia |
Marc: |
LEADER 02262naa a2200265 a 4500 001 2111572 005 2019-10-03 008 2019 bl uuuu u00u1 u #d 024 7 $a10.1016/j.compositesb.2019.107281$2DOI 100 1 $aCADEMARTORI, P. H. G. de 245 $aAlumina nanoparticles as formaldehyde scavenger for urea-formaldehyde resin$brheological and in-situ cure performance.$h[electronic resource] 260 $c2019 520 $aFormaldehyde emission in the environment from thermosetting resins, like urea-formaldehyde (UF), is one of the most negative aspects of wood-based composite panels. UF resins with low or zero formaldehyde emission and keeping or improving their remarkable properties have been designed by different approaches, with special attention to organic and inorganic nanofillers. Although formaldehyde emission can be mitigated, controlling of rheology kinetics, curing and thermal stability are essential to avoid restrictions for practical applications. Here, we investigated the incorporation of small percentages of Al2O3 nanoparticles into UF resin regarding its rheology, thermodynamic mechanics, thermal kinetics and morphology. Changes on formaldehyde emission was determined by desiccator method and qualitatively illustrated by thermogravimetry-mass spectrometry analysis. The Al2O3 incorporation without significant agglomerations changed the viscosity of UF resin, presenting a shear thinning behavior, especially for higher quantity of nanoparticles. Likewise, analysis of thermodynamic mechanisms shows Al2O3 as an effective additive for UF resin without changing important curing parameters like vitrification point and gel temperature. Al2O3 nanoparticles are also effective to reduce the formaldehyde emission during the UF resin cure reactions at high temperatures and up to 14% in MDF composite panels at environmental temperatures. 650 $aNanoparticles 650 $aRheology 653 $aAlumina 653 $aCure behavior 653 $aFormaldeído 653 $aNanopartícula 653 $aReologia 653 $aThermosetting resin 700 1 $aARTNER, M. A. 700 1 $aFREITAS, R. A. de 700 1 $aMAGALHAES, W. L. E. 773 $tComposites Part B$gv. 176, article 107281, Nov. 2019. 9 p.
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