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91.
92.
Luis Carlos da Silva Ramos Joao Shogiro Tango Angelo Savi Nilson Roberto Leal 《Journal of the American Oil Chemists' Society》1984,61(12):1841-1843
Thirty-six castorbean varieties were surveyed for oil and fatty acid composition, in order to determine variability of these
seed compounds. A large variability of seed oil percentage was observed, ranging from 39.6 to 59.5%. Concerning the fatty
acids, little variability was observed for ricinoleic acid, which was the most abundant in the oil, ranging from 83.65 to
90.00%. The other fatty acids appeared in small concentrations and showed a small range: 0.87 to 2.35, 0.68 to 1.84, 2.96
to 5.64, 3.19 to 5.98, and 0.34 to 0.91%, for palmitic, stearic, oleic, linoleic, and linolenic acid, respectively. Non-significant
correlations were observed between fatty acids and seed oil percentage. However, significant correlations were observed among
fatty acid concentrations: positive and negative ones. These significant correlations could be associated with the biosynthetic
pathways of the fatty acids, which are not fully elucidated. They suggest, however, that selection for a particular fatty
acid will tend to increase those positively correlated, and decrease those negative ones. Selection and plant breeding techniques
could then be applied to modify the oil content of the castorbean seeds, considering the variability observed. For the fatty
acid composition, however, the variability was not large enough to make substantial changes in their concentrations by selection
procedures. More varieties should be surveyed to find out if such variability is available. 相似文献
93.
Carlos Rivas-Costa Luis Anido-Rifón Miguel A. Gómez-Carballa Sonia Valladares-Rodríguez Roberto Soto-Barreiros 《International journal of human-computer interaction》2014,30(6):480-494
This article discusses a modular, accessible platform that provides a computing environment for people with disabilities accessible through adapted control devices and the television set at users’ homes. Relying on a standard television set as the presentation device allows dependent individuals, especially people with disabilities, to introduce new technological advances in communication and information management in their everyday lives. As a proof-of-concept, the solution presented offers a collection of educational and training services related to teleworking and the search of employment targeted to people with disabilities. A smart job advisor included among these services, which was designed to help our target users to locate job offers that best suit the abilities and disabilities of a particular individual, is also discussed to illustrate how semantic technologies can be applied to increase the perceived accessibility and inclusion by reducing the dependence from other persons. The platform developed, the introduction of semantic technologies, and the way adapted interfacing and presentation devices were integrated may also serve as inspiration to provide services to people with disabilities. 相似文献
94.
This article introduces a new method for model falsification using set‐valued observers, which can be applied to a class of discrete linear time‐invariant dynamic systems with time‐varying model uncertainties. In comparison with previous results, the main advantages of this approach are as follows: The computation of the convex hull of the set‐valued estimates of the state can be avoided under certain circumstances; to guarantee convergence of the set‐valued estimates of the state, the required number of previous steps is at most as large as the number of states of the nominal plant; and it provides a straightforward nonconservative method to falsify uncertain models of dynamic systems, including open‐loop unstable plants. The results obtained are illustrated in simulation, emphasizing the advantages and shortcomings of the suggested method. Copyright © 2013 John Wiley & Sons, Ltd. 相似文献
95.
Carlos G. Levi Eric Sommer Scott G. Terry Amalia Catanoiu Manfred Rühle 《Journal of the American Ceramic Society》2003,86(4):676-85
The microstructure of Al2 O3 formed by oxidation of a model NiCrAlY alloy during electron-beam physical vapor deposition of ZrO2 –7.6 mol% YO1.5 is examined and compared with that formed on the bare substrate. The growth rate, morphology, and chemical composition of the oxide vary among the different constituents of the alloy surface and are further influenced by the O2 partial pressure and the physical presence of the thermal barrier coating (TBC) layer. These differences, however, are largely limited to the outer oxide layer. The interplay between the TBC and the growing oxide leads to the formation of a fine-grain Al2 O3 –ZrO2 "mixed zone" within the thermally grown oxide. A mechanism is outlined to explain this behavior, based on the dissolution of ZrO2 in a transient Al2 O3 structure growing by outward diffusion of Al, and its subsequent reprecipitation when the metastable phase transforms to the stable α-Al2 O3 form. 相似文献
96.
Michael Gelfer Carlos Avila‐orta Lizhi Liu Ling Yang Benjamin Chu Benjamin S. Hsiao Hyun H. Song Mayu Si Miriam Rafailovich Andy H. Tsou 《Polymer Engineering and Science》2002,42(9):1841-1851
A series of nanocomposites prepared by melt‐blending of cloisite‐based organoclays with poly(ethylene‐vinylacetate) (EVA) and neutralized poly (ethylene‐methacrylic acid) (EMA) copolymers were investigated via DSC, small‐angle X‐ray scattering (SAXS), and rheological techniques. SAXS results indicated partial clay exfoliation in all samples. In both EMA and EVA systems, the nominal melting temperature Tm and bulk crystallinity are not significantly affected by the presence of organoclays, suggesting that clay particles are predominantly confined in the amorphous phase. In rheological measurements (above Tm), the EVA‐clay system demonstrated a solid‐like rheological behavior under the small‐strain oscillatory shear, yet it was able to yield and flow under a steady shear, which is the characteristic of physical crosslinking. In contrast, the EMA‐clay system exhibited a melt‐like rheological behavior, where the influence of organoclay on the thermorheological behavior of the EMA composite was quite minimal. We propose that the carbonyl groups of vinylacetate in EVA interact with the clay surface, resulting in a strong physically crosslinking like interaction in the melt. On the other hand, the interaction between EMA and clay is weak because of repulsion between carboxyl anions and negatively charged clay surface. 相似文献
97.
Raul C. Maranhão Thais B. Cesar Suzana R. Pedroso-Mariani Mario H. Hirata Carlos H. Mesquita 《Lipids》1993,28(8):691-696
A protein-free microemulsion (LDE) with a lipid composition resembling that of low-density lipoprotein (LDL) was used in metabolic
studies in rats to compare LDE with the native lipoprotein. LDE labeled with radioactive lipids was injected into the bloodstream
of male Wistar rats, and plasma kinetics of the labeled lipids were followed on plasma samples collected at regular intervals
for 12 h after injection. The 24-h LDE uptake by different tissues was also measured in tissue samples excised after the animals
had been sacrificed. We found that LDE plasma kinetics were similar to those described for native LDL [fractional clearance
rate (FCR) of cholesteryl ester, 0.42±0.11 h−1]. The major site for LDE uptake was the liver, and the tissue distribution of the LDE injected radioactivity was as one would
expect for LDL. To test whether LDE was taken up by the specific LDL receptors, the LDE emulsion was injected into rats treated
with 17α-ethinylestradiol, which is known to increase the activity of these receptors; as expected, removal of LDE from the
bloodstream increased (FCR=0.90±0.35 h−1). On the other hand, saturation of the receptors that remove remnants by prior infusion of massive amounts of lymph chylomicrons
did not change LDE plasma kinetics. These results indicate that LDE is cleared from plasma by B,E receptors and not by the
E receptors that remove remnants. Incorporation of free cholesterol into LDE increased LDE plasma clearance. Incubation studies
also showed that LDE incorporates a variety of apolipoproteins, including apo E, a ligand for recognition of lipoproteins
by specific receptors. Our data suggest that LDE can be a useful tool to test LDL metabolism and B,E receptor function. 相似文献
98.
Mari Lou Balmer Fred F. Lange Carlos G. Levi 《Journal of the American Ceramic Society》1994,77(8):2069-2075
Aqueous solutions of zirconium acetate and aluminum nitrate were spray pyrolyzed at 250°C and upquenched to different temperatures to yield metastable solid solutions of composition Zr(1− x ) Alx O(2− x /2) . An amorphous oxide forms first during pyrolysis which subsequently crystallizes as a single phase for x ≤ 0.57 (≤40 mol% Al2 O3 ). The crystallization temperature increased with Al2 O3 content. Electron diffraction, supported by Raman spectroscopy, indicates that the initial phase is tetragonal. At higher temperatures, the initial solid solation partitions to other metastable phases, viz., t -ZrO2 +γ-Al2 O3 , prior to achieving their equilibrium phase assemblage, m -ZrO2 +α-Al2 O3 . Partitioning yields a nanocomposite microstructure with grain sizes of 20–100 nm, compared to the 3 to 5 nm in the initial, single phase. Compositions containing 45 to 50 mol% Al2 O3 concurrently crystallize and partition. The structure selected during crystallization and the partitioning phenomena are discussed in terms of diffusional constraints during crystallization, which are conceptually similar to those operating during rapid solidification. 相似文献
99.
Blends of statistical copolymers containing ethylene/hexene (PEH) and ethylene/butene (PEB) exhibited the behavior of upper critical solution temperature (UCST). The interplay between the early and intermediate stage liquid-liquid phase separation (LLPS) and crystallization of the PEH/PEB 50/50 blend was studied by time-resolved simultaneous small-angle X-ray scattering (SAXS) and wide-angle X-ray diffraction (WAXD) techniques. Samples were treated by two different quench procedures: in single quench, the sample was directly quenched from 160 °C to isothermal crystallization temperature of 114 °C; while in double quench, the sample was firstly quenched to 130 °C for 20 min annealing, where LLPS occurred, and then to 114 °C. It was found that in the early stage of crystallization, the integrated values of Iq2 and crystallinity, Xc, in the double quench procedure were consistently higher than those in the single quench procedure, which could be attributed to accelerated nucleation induced by enhanced concentration fluctuations and interfacial tension. In the late stage of crystallization, some morphological parameters were found to crossover and then reverse, which could be explained by retardation of lamellar growth due to phase separation formed during the double quench procedure. This phenomenon was also confirmed by DSC measurements in blends of different compositions at varying isothermal crystallization temperatures. The crystal lamellar thickness determined by SAXS showed a good agreement with TEM observation. Results indicated that the early stage LLPS in the PEH/PEB blend prior to crystallization indeed dictated the resulting lamellar structures, including the average size of lamellar stack and the stack distribution. There seemed to be little variation of lamellar thickness and long period between the two quenching procedures (i.e., single quench versus double quench). 相似文献
100.
A general method is proposed for prediction of the flow rate and maximum velocity in the isothermal, steady, uniform, laminar flow of any incompressible, time-independent non-Newtonian fluid in straight open channels of arbitrary cross section. The method requires only a knowledge of two geometric coefficients and a function of shear stress, used to characterize the behavior of the fluid model. The slip effect at the solid boundary has been taken into consideration. Numerical values of the geometric parameters have been determined for flow through an inclined plane of infinite width, semi-circular, semi-elliptical, rectangular, and 90° and 60° symmetric triangular open channels. Applications have been made to various non-Newtonian fluid models such as the power-law, Bingham, Ellis, Meter and the Reiner-Rivlin general model. Numerical examples are presented. A generalization of the Fanning friction factor — Reynolds number is also presented. The problem of determining the point of transition from laminar to turbulent flow in the general case is examined, as is the problem of prediction of the friction factor in turbulent flow. 相似文献