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Teste e comparação de modelos matemáticos para o traçado de curvas granulométricas. Infoteca-e
LIMA, J. E. F. W.; SILVA, E. M. da.
RESUMO: O conhecimento sobre a distribuição granulométrica de partículas sólidas é essencial para as áreas de material de construção, mecânica dos solos, física dos solos, hidrossedimentologia, entre outras. Em geral, as técnicas utilizadas para a avaliação da distribuição granulométrica de amostras resultam em valores pontuais, dependendo de posterior interpolação para o traçado da curva granulométrica e a obtenção de diâmetros característicos específicos. A transformação de valores pontuais em funções contínuas pode ser realizada por meio de modelos matemáticos. Entretanto, poucos estudos têm sido desenvolvidos com o fito de determinar o melhor modelo para o ajuste de curvas granulométricas. Sendo assim, o objetivo deste trabalho foi testar e comparar 14...
Tipo: Boletim de Pesquisa e Desenvolvimento (INFOTECA-E) Palavras-chave: Soil chemicophysical properties; Non-linear regression; Growth rate; Growth curves.; Curva de Crescimento; Física do Solo; Granulometria; Regressão Linear; Solo; Textura do Solo.; Granules; Soil texture..
Ano: 2003 URL: http://www.infoteca.cnptia.embrapa.br/infoteca/handle/doc/569214
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Limit between stages I and II of a seed imbibition curve Scientia Agricola
Pinho,Sheila Zambello de; Carvalho,Lídia Raquel de; Delachiave,Maria Elena Aparecida.
A knowledge of the imbibition stages shown by different species, is essential in research projects aiming at improvement of seed quality by treatments such as osmotic conditioning, initial wetting, and the use of bioregulators. The objective of this study was to establish a methodology to determine the limit between the first and second stages of the process, considering the model W = f(t) - (a - w0)exp(-kt), using statistical tests. This limit was determined using an asymptotic distribution of an estimator function. The data point beyond which the difference (W*) is no longer significant was determined using Student's T statistics. The model is <img border=0 id="_x0000_i1026" src="../../../img/revistas/sa/v61n1/a03img01.gif" align=absmiddle > or =...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Water absorption; Non-linear regression; Germination.
Ano: 2004 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162004000100003
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A study of in situ degradability: heterogeneity of variances and correlated errors Scientia Agricola
Savian,Taciana Villela; Muniz,Joel Augusto.
Degradation models exhibit a non-linear behavior and the selection of a model to describe the degradability depends on the coherence of the model with the involved biological events. The purpose of this study is to evaluate the behavior of the parameters of the degradation model proposed by Mertens &amp; Loften, adjusted to the results of an in situ degradability trial. The experiment evaluated the potential degradable residue of neutral detergent fiber (NDF) of coastcross grass (Cynodon dactylon × Cynodon nlemfuensis) submitted to two cutting ages (30 and 90 days), with three replicates. For each cutting age, the potentially degradable residue of NDF was studied using fifteen incubation times (0; 0,5; 1; 3; 6; 9; 12; 18; 34; 35; 48; 56; 72; 96 e 120...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Ruminal degradability; Non-linear regression; Parameters estimation; Coast-cross grass.
Ano: 2007 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0103-90162007000500013
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Critical analyses when modeling tree biomass to ensure additivity of its components Anais da ABC (AABC)
BEHLING,ALEXANDRE; PÉLLICO NETTO,SYLVIO; SANQUETTA,CARLOS ROBERTO; CORTE,ANA PAULA D.; AFFLECK,DAVID L.R.; RODRIGUES,AURÉLIO L.; BEHLING,MARCOS.
ABSTRACT It is presented the theme additivity of biomass of tree components. To evaluate and discuss this context, experimental information collected in forests of Acacia mearnsii De Wild. was used. Equations for components (stem and crown) and total biomass were fitted by means of two procedures: 1) generalized nonlinear least squares and 2) weighted-nonlinear seemingly unrelated regressions. Analyzing the performance of the estimators, it can be concluded that the two tested procedures are equivalent. On the other hand, this conclusion differs when evaluated the consistency and efficiency of the estimators. Fitting equations for the components and for the total biomass by an independent way is not realistic, because from a biological point of view the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Biomass; Biological consistency; Non-linear regression; System of equations.
Ano: 2018 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0001-37652018000401759
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Comparison of methods for phenotypic stability analysis of cassava (Manihot esculenta Crantz) genotypes for yield and storage root dry matter content BABT
Kvitschal,Marcus Vinícius; Vidigal Filho,Pedro Soares; Scapim,Carlos Alberto; Gonçalves-Vidigal,Maria Celeste; Sagrilo,Edvaldo; Pequeno,Manoel Genildo; Rimoldi,Fabrício.
The objective of this work was to compare different phenotypic stability methods by using yield and storage root dry matter content data of eight cassava genotypes, assessed in eight environments in northwest of Paraná State, Brazil. All the methodologies applied showed to be able to study the stability of cassava genotypes, but each with its peculiarities. The methodologies of Eskridge, Annicchiarico and Lin and Binns were the most appropriated on situation with smaller effect of G x E interaction. The AMMI analysis and the Toler and Burrows methodology were the most specific on detailing specific adaptations of cassava genotypes to favorable and unfavorable environments. It could be suggested to use simultaneous AMMI analysis and Toler and Burrows...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Manihot esculenta; Correlation; Stability; Safety first indexes; Non-linear regression; AMMI analysis.
Ano: 2009 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1516-89132009000100022
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Degradability study of neutral detergent fiber of coast cross (Cynodon dactylon x Cynodon nlemfunensis) Ciência e Agrotecnologia
Savian,Taciana Villela; Muniz,Joel Augusto; Aquino,Luiz Henrique de; Banys,Vera Lúcia; Ferreira,Daniel Furtado.
The objective of this work was to fit the degradation model proposed by Orskov &amp; McDonald (1979) to data of an in situ degradability trial. Neutral detergent fiber degradations (NDF) of coast cross grass (Cynodon dactylon x Cynodon nlemfunensis) were submitted to twelve cutting ages (30, 60, 90, 120, 150, 180, 210, 240, 270, 300, 330 and 360 days) in a complete block design. At each cutting age, NDF degradation was investigated using nine incubation times (0, 3, 6, 12, 24, 48, 72, 96 and 120 hours) in a split-plot design, taking cutting age as main plots and incubation time as subplots. Each plot comprised a non-lactating cow with a permanent ruminal fistula. Variances of the parameter estimates were also obtained, as well as expressions for the...
Tipo: Info:eu-repo/semantics/article Palavras-chave: Coast cross; Degradability model; Fitting quality; Non-linear regression.
Ano: 2007 URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S1413-70542007000400035
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