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  • Polymer and Materials Science  (8)
  • Life and Medical Sciences  (2)
  • N availability index  (2)
  • Oxisol  (2)
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Keywords
  • 1
    Electronic Resource
    Electronic Resource
    Solubility and availability to sugarcane (Saccharum Spp.) of two silicate materials (1988)
    Springer
    Nutrient cycling in agroecosystems 16 (1988), S. 3-13 
    Details
    ISSN: 1573-0867
    Keywords: dicalcium orthosilicate ; calcium metasilicate ; mini-granulation ; extractable Si ; Si in saturation extract ; Oxisol ; Andept
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Silicate materials, dicalcium orthosilicate (Ca2SiO4), calcium metasilicate (CaSiO3), and mini-granulated CaSiO3, were incorporated into three highly weathered, low-Si soils. The mixtures were moistened to field moisture-holding capacity and incubated in plastic bags for 60 days at approximately 25°C, after which Si was extracted. Application rates of silicate materials were 0, 460, 920, and 1380 mg Si per kg soil. Two ranges of particles sizes, 0.25 to 0.84 mm and 0.074 to 0.15 mm CaSiO3 and Ca2SiO4 were compared. The soils were a Typic Gibbsiorthox, pH 4.6; a Humoxic Tropohumult, pH 4.2; and a Typic Hydrandept, pH 5.0. Materials were evaluated by four extraction procedures: shaking in water, water displacement from saturated soil, shaking in ammonium acetate solution, and biologically by roots of sugarcane (Saccharum Spp. hybrid). Silicate from the CaSiO3 materials were generally more readily extracted chemically and biologically than silicate from the Ca2SiO4. Solubility and availability of Si usually increased as primary particle size of the silicate materials decreased. The exceptions were associated with the most acid (pH 4.2) Ultisol. Mini-granulation did not reduce the effectiveness of CaSiO3 thus confirming agronomic feasibility of mini-granulation. Plant uptake of Si was most closely related to water-extractable soil Si, followed by Si in saturation extracts and then by NH4 OAc-extractable Si.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01053310
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  • 2
    Electronic Resource
    Electronic Resource
    Chemical characterization of two extracts used in the determination of available soil nitrogen (1982)
    Springer
    Plant and soil 64 (1982), S. 331-341 
    Details
    ISSN: 1573-5036
    Keywords: Humic substances ; Molecular weight distribution ; N availability index ; Ninhydrindetectable N ; Relative N uptake ; Soil proteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary Two soil extracts used for chemical indexes for N availability, 0.01M NaHCO3 and boiling 0.01M CaCl2, were analyzed in effort to learn more about the nature of the extracted organic matter (O.M.). The two extracts appeared to remove different fractions of the soil O.M. A study of five soils showed that the C/N value of the NaHCO3 extract (following decarbonation) was significantly higher than that of the total soil O.M.; while the C/N value in the boiling CaCl2 extract was not significantly different from that in the soil O.M. There was also significant variation in C/N values among soils for the boiling CaCl2 extract. The extracts of three soils were analyzed for apparent molecular weight distribution using gel filtration and the results compared to those for base-extracted humic substances. Almost all the molecules in the extracts had apparent molecular weights less than 21,000 daltons while 21 to 47% of the humic substances from the same soils (extracted with 0.5M NaOH) had molecular weights greater than 21,000 daltons. In the boiling CaCl2 extract, 78 to 87% of the humic substances had apparent molecular weights less than 1,000 daltons, whereas with the NaHCO3 extract, 42 to 83% of the humic substances were in the 1,000 to 21,000 dalton range. Forty-three to 92% of the N extracted by the NaHCO3 was in protein form, and 8 to 30% was ninhydrin-detectable. In the boiling CaCl2 extract 25 to 30% of the extracted N was ninhydrin-detectable. For the same 10 soils, ninhydrin-detectable N values of the boiling CaCl2 extract appeared closely related to greenhouse and field relative N uptake, while the ninhydrin-detectable N values of the NaHCO3 extract appeared unrelated to both. The protein N and protein in plus ninhydrin-detectable N values of the NaHCO3 extract were closely related to greenhouse relative N uptake only. The results of this study indicated that specific fractions of the soil O.M. were being extracted by the two solutions and that significant differences existed in the chemical nature of the two extracts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02372516
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  • 3
    Electronic Resource
    Electronic Resource
    Effect of temperature and time of storage of dry soil samples on a chemical index of N availability (1982)
    Springer
    Plant and soil 66 (1982), S. 81-89 
    Details
    ISSN: 1573-5036
    Keywords: Extractable organic matter ; N availability index ; Organic matter ; Organic N ; Soil storage
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The effect was studied of storage temperature on the index of available soil N wich uses U.V. absorbance of a 0.01M NaHCO3 extract as an indicator. The U.V. absorbance was found to increase at a non-linear rate for four soils stored at temperatures of 50, 75, and 150°C. The change in extract absorbance due to extended soil storage at each of these temperatures was positively correlated to the percent organic matter, percent N, C/N value and concentration of humic substances in soils, but not to the extract absorbance prior to soil storage. These findings were not consistent with room temperature storage data which showed a linear increase in extract absorbance with soil storage time. The change in absorbance for the room temperature case was not related to any of the soil parameters mentioned above. Analysis of a soil stored at 105°C showed an increase in ninhydrin-detectable N, protein N and Kjeldahl N of the NaHCO3 extract, while the apparent molecular weight distribution of extracted organic matter (as determined by gel filtration) showed only a slight change. As a comparison to the NaHCO3 extract, a boiling CaCl2 extract of the same soil was also analyzed; and the absorbance at 260 nm was found to increase in a curvilinear fashion with starage time at 75°C but to less of an extent than was noted with the NaHCO3 extract. Nitrogen availability indexes based on the U.V. absorbance of these extracts, particularly those utilizing the NaHCO3 extract, would be significantly affected by soil storage at elevated temperatures.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02203405
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  • 4
    Electronic Resource
    Electronic Resource
    Interactions of soil pH, nutrients and moisture on phytophthora root rot of avocado (1984)
    Springer
    Plant and soil 81 (1984), S. 165-176 
    Details
    ISSN: 1573-5036
    Keywords: Avocado ; Ca ; Mn ; Oxisol ; P ; pH ; Phytophthora root rot ; Soil water
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary This experiment employed a factorial design combining 4 soil pH levels, 3 soil moisture levels, with and without the addition ofPhytophthora cinnamomi to the soil to evaluate the conditions that lead to Phytophthora root rot of avocado. An inverse relation between soil pH and leaf production (and root-weight) was observed in nondiseased plants. In soil infested withP. cinnamomi, plant growth and root weights were much depressed by low soil pH, and especially by low soil pH coupled with high soil moisture contents. These interactions were statistically highly significant. Root weights in pots withP. cinnamomi were closely related to the incidence of disease. A disease index was used to visually assess the conditions of roots. Isolation of the pathogen from diseased plant roots confirmed the accuracy of the disease index. A process of elimination suggsts that favorable soil Ca level and not high pHper se was responsible for disease suppression and that the devastating effects of low soil pH was produced by high Mn (and possibly Al) and associated low levels of Ca and P in soil solutions, which led to breakdown of biological control mechanisms.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02197148
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  • 5
    Electronic Resource
    Electronic Resource
    Synthetic sequence effects in polyurethane-poly(n-butyl methacrylate) mixtures: Grafting and mechanical properties (1990)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 41 (1990), S. 1281-1298 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Morphology, stress-strain properties, and grafting have been investigated in highly phase-separated polyurethane (PU)-poly(n-butyl methacrylate) (PBMA) mixtures as a function of the sequence of formation of the components, both linear (l) and crosslinked (x), in the presence of each other. In the range of 0.3-0.7 weight fraction of PU, a morphology of PBMA particles in a PU matrix results. Particle size depends on matrix viscosity at the time of PBMA formation, decreasing as viscosity increases. The PBMA (l) particles are spherical; PBMA (x) particles are irregular in shape when formed in a fluid medium but tend to become spherical as the delay time before the onset of their formation is increased. Grafting, decreasing with increasing delay time, is observed between PBMA (l) particles and the PU (x) or PU (l) matrix. The grafting results from transesterification between BMA and the polyol precursors to the PU. Two families of mechanical properties are found, depending generally more on particle shape than size. Systematic trends of property values through a series of samples of constant composition, but increasing delay times, are observed with greater variation in the series with PBMA (x) particles; the trends are explainable in terms of matrix immobilization by the particles.
    Additional Material: 11 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1990.070410536
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  • 6
    Electronic Resource
    Electronic Resource
    Photodegradation of poly(methyl methacrylate) in solution and the effect of added solutes (1967)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 11 (1967), S. 2373-2379 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Poly(methyl methacrylate) has been photolyzed with 2537 A. radiation in dioxane and in methylene chloride at about 25°C. in the presence and absence of air. In degassed solutions, quantum yields for random scission are only slightly affected by either intensity or polymer concentration. Oxygen is an apparent inhibitor for photodegradation. The inhibiting and sensitizing effects of a variety of added solutes, including aromatic hydrocarbons, aliphatic dienes, and ketones were investigated; the behavior is similar whether or not oxygen is present. The results are best explained on the basis of an electronic energy transfer mechanism involving the lowest excited triplet levels of the polymer and the added solutes.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1967.070111124
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  • 7
    Electronic Resource
    Electronic Resource
    Photolytic degradation of some poly(alkylene polysulfides)Presented in part before the Society of Plastic Engineers, Regional Technical Conference, Washington, D. C., June 4, 1964, and before the Organic Coatings and Plastics Chemistry Division at the 148th Meeting of the American Chemical Society, Chicago, September 1, 1964. (1965)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Applied Polymer Science 9 (1965), S. 3489-3497 
    Details
    ISSN: 0021-8995
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Poly(methylene disulfide), poly(methylene tetrasulfide), poly(ethylene disulfide), and poly(ethylene tetrasulfide) have been subjected to ultraviolet radiation in vacuum at 50°C. Weight losses during photolysis include both low molecular weight compounds and readily condensable polymeric materials; the latter account for the greater proportion of the weight losses. Carbon monosulfide, isolated as its polymer, and hydrogen sulfide are major photolytic products. Carbon disulfide is a major product from the methylene but not from the ethylene polymers. The tetrasulfide polymers during irradiation from volatile products which on condensation give the original polymer. A mechanism of degradation compatible with these findings is suggested.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/app.1965.070091025
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  • 8
    Electronic Resource
    Electronic Resource
    Morphogenetic studies of the rabbit XLI. Gradients of correlation in the architecture of morphology (1970)
    New York, NY [u.a.] : Wiley-Blackwell
    American Journal of Anatomy 128 (1970), S. 137-145 
    Details
    ISSN: 0002-9106
    Keywords: Life and Medical Sciences ; Cell & Developmental Biology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Significant sex and strain differences in correlation of bone, body and skeletal weights show significant localized effects of sex and strain and a combination of both. Individually they seem to lack biological meaning. However, when considered in relation to the ponderal correlations, of which they are a part, they fall into place at the distal ends of a graded linear correlation series, both within and between limbs; and similarly between mandible and sacrum, respectively, with each bone of both limbs. The pattern of these gradients reveals a linear decline in correlation of bones with distance (rule of neighborhood, Karl Pearson) in most cases, but the exceptions are such as can be related to the functions in which they cooperate. In this way they demonstrate at least two major unifying genetic influences. One associates sex and strain with locomotion and the other with the incipient upright investigative posture of the Lagomorphs (including the rabbit). The expected effect of sex on the pelvis is apparently not expressed by these ponderal measurements. The manner in which this correlation approach, based on well established genetic growth differences, converges with the phylogenetic and ontogenetic concepts of normal and abnormal growth of bone in limbs and cranio-facial development suggests that a combination of correlation and epigenetic analysis would be helpful in establishing a sound genetic background for the newer biomechanic, functional matrix and architectonic approaches.
    Additional Material: 3 Tab.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/aja.1001280202
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  • 9
    Electronic Resource
    Electronic Resource
    Charge transfer interaction and electrical conductivity of poly(vinyl acetals) containing dispersed TCNQ radical anion salts (1982)
    New York : Wiley-Blackwell
    Journal of Polymer Science: Polymer Chemistry Edition 20 (1982), S. 2765-2772 
    Details
    ISSN: 0360-6376
    Keywords: Physics ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Charge transfer (CT) interaction is described in semiconducting dispersions of TCNQ complex salt \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm Et}_3 {\rm NH}^+ ({\rm TCNQ})_2^{\cdot^{\hskip-3.7pt\hbox{--}}}$\end{document} with and without added TCNQ°, in poly(vinyl acetal) matrices in which the electron-donor moiety is varied. The extent of CT interaction was determined in films and in solution (DMF, acetonitrile, or methylene chloride) through the absorbances at 398 nm (\documentclass{article}\pagestyle{empty}\begin{document}$ {\rm TCNQ}{\ }^{\cdot^{\hskip-3.7pt\hbox{--}}}$\end{document} and TCNQ°) and 857 nm \documentclass{article}\pagestyle{empty}\begin{document}$ {\rm TCNQ}{\ }^{\cdot^{\hskip-3.7pt\hbox{--}}}$\end{document}. Resistivity of the conductive films was related to the stoichiometry of TCNQ species in the films and found to have a minimum at \documentclass{article}\pagestyle{empty}\begin{document}$[{\rm TCNQ}^\circ]/[{\rm TCNQ}{\ }^{\cdot^{\hskip-3.7pt\hbox{--}}}]\simeq 1$\end{document}. Lower resistivities were attained with films having a uniform, densely packed dispersion of microcrystallites which were obtained at a relatively slow solvent removal rate. With this particular complex salt, strong electron-donor polymers are found to be better matrices for semiconductivity.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1982.170201003
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  • 10
    Electronic Resource
    Electronic Resource
    Photolysis of poly-α-methylstyrene (1962)
    Hoboken, NJ : Wiley-Blackwell
    Journal of Polymer Science 56 (1962), S. 507-517 
    Details
    ISSN: 0022-3832
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The photodegradation of thin films of poly-α-methylstyrene by near ultraviolet radiation has been studied in vacuum at 27 and 115°C. Changes taking place during photolysis were followed by a determination of monomer formation by ultraviolet spectroscopy, residue molecular weight through a measurement of intrinsic viscosity, and volatile products by mass spectroscopy. Gross features of the photolysis include random chain scission in the polymer with subsequent depolymerization of the radicals formed to yield small amounts of monomer; the kinetic chain length is on the order of 15 in the temperature range studied. Quantum yields at 27°C. for chain scission and monomer formation are 1 × 10-3 and 7 × 10-3, respectively. At 115°C. the quantum yields are 2 × 10-2 and 0.5. Small quantities of hydrogen, CO2, CO, and a number of hydrocarbons were liberated during irradiation. An approximate one-to-one correlation between the number of main chain scissions and CO2 + CO molecules evolved was found, suggesting the occurrence of chain scission at weak linkages involving oxygen.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pol.1962.1205616422
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