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51.
To investigate species-specific decomposition rates of litter from native (Quercus faginea) and introduced (Eucalyptus globulus) tree species in Portugal, we monitored changes in the phenolic signature of leaf litter during decomposition as mediated by an aquatic, Proasellus coxalis (Isopoda: Asellota), and two terrestrial, Porcellio dispar and Eluma caelatum (Isopoda: Oniscidea), detritivores. Although the litter of Eucalyptus and Quercus did not differ in overall protein precipitation capacity, we detected differences in terms of contents of particular phenolic compounds and phenol oxidation products. Accordingly, we observed food-specific consumption rates in Proasellus, but not in the terrestrial isopods. Proasellus digested Eucalyptus at significantly higher rates than Quercus, whereas the opposite was the case for Eluma, and Porcellio digested both litter types equally well. Despite slight differences in detail, effects of Proasellus on changes in the signature of litter phenolics were similar for both litter types, whereas terrestrial isopods—Porcellio and Eluma, although they differed from each other—digestively degraded phenolic compounds in Eucalyptus and Quercus litter, respectively, in different ways. Overall, however, degradation of litter phenolics was similarly effective on both litter types. From these data, we conclude that decomposition of Eucalyptus litter does not proceed more slowly than of litter from native Portuguese trees. 相似文献
52.
Stephen Q. Zhou Liming Wang Xiugao Liao Georges Manuel William P. Weber 《Journal of Inorganic and Organometallic Polymers and Materials》1991,1(2):199-210
High molecular weight poly(1,1-dimethyl-1-germa-cis-pent-3-ene), poly(1,1-diphenyl-1-germa-cis-pent-3-ene), poly(1,1-dimethyl-1-sila-cis-pent-3-ene), and poly(1-methyl-1-phenyl-1-sila-cis-pent-3-ene) have been prepared. The thermal stability of these polymers is found to increase with their molecular weight. 相似文献
53.
Aranzazu García M Victoria Ruiz-Méndez Concepción Romero Manuel Brenes 《Journal of the American Oil Chemists' Society》2006,83(2):159-164
By definition, virgin olive oil is consumed unrefined, although a great proportion of the olive oil produced has to be refined
to render it edible. Phenolic compounds are among the substances eliminated during the refining process; in the present work
these were characterized by HPLC, and their evolution during the different refining steps was studied. The complete refining
process removed most polyphenols from oils, but the behavior of individual compounds at each step also was observed. o-Diphenols
(hydroxytyrosol, catechol, and hydroxytyrosol acetate) and flavonoids (luteolin and apigenin) were eliminated first during
the alkaline treatment. Tyrosol and 4-ethylphenol remained in the oil until the deodorization step. A large amount of phenolic
compounds was discovered in the refining by-products such as soapstocks and deodorization distillates. In the latter streams,
the concentrations of tyrosol and 4-ethylphenol reached up to 149 and 3720 mg/kg by-product, respectively. This high level
of 4-ethylphenol and its well-known strong off-odor can interfere during further processing of the deodorization distillates,
and this must be taken into account when deciding what is to become of them. Similarly, the results of this work open the
possibility of recovering phenolic compounds from the “second centrifugation olive oils” by adding a new washing step prior
to the refining process. By including this new step, the most polar polyphenols, hydroxytyrosol and tyrosol, will diffuse
from oil to water and a concentration of up to 1400 mg/L of hydroxytyrosol may be achieved. 相似文献
54.
Jose Ygnacio Pastor Jaime Planas Manuel Elices 《Journal of the American Ceramic Society》1993,76(11):2927-2929
A new technique that provides stable fracture tests in brittle ceramic materials at room and at high temperature is presented. This technique uses the crack mouth opening displacement signal from a laser extensometer to feed the servo control of a hydraulic testing machine. In this way it is possible to obtain—in addition to the fracture toughness—the fracture energy and the R -curve, in a single test. 相似文献
55.
Kiyoshi Hirao Masayoshi Ohashi Manuel E. Brito Shuzo Kanzaki 《Journal of the American Ceramic Society》1995,78(6):1687-1690
Silicon nitride with a preferred orientation of large elongated grains was obtained by tape casting of raw powder slurry seeded with rodlike β-Si3 N4 particles, followed by a gas pressure sintering under 1 MPa nitrogen pressure. The large elongated grains developed from seeds lay in planes parallel to the casting direction in a two-dimensional distribution. Increased fracture toughness (11.1 MPa·m1/2 ) and bending strength (1100 MPa) were achieved in the direction perpendicular to the grains alignment compared to specimens with a random distribution of elongated grains. Morover, the specimens exhibited a high Weibull modulus of 46 due to the uniform distribution of large grains. 相似文献
56.
Manuel Baena-García José M. Carmona-Cejudo Rafael Morales-Bueno 《Journal of Computer and System Sciences》2014
Discovering frequent factors from long strings is an important problem in many applications, such as biosequence mining. In classical approaches, the algorithms process a vast database of small strings. However, in this paper we analyze a small database of long strings. The main difference resides in the high number of patterns to analyze. To tackle the problem, we have developed a new algorithm for discovering frequent factors in long strings. We present an Apriori-like solution which exploits the fact that any super-pattern of a non-frequent pattern cannot be frequent. The SANSPOS algorithm does a multiple-pass, candidate generation and test approach. Multiple length patterns can be generated in a pass. This algorithm uses a new data structure to arrange nodes in a trie. A Positioning Matrix is defined as a new positioning strategy. By using Positioning Matrices, we can apply advanced prune heuristics in a trie with a minimal computational cost. The Positioning Matrices let us process strings including Short Tandem Repeats and calculate different interestingness measures efficiently. Furthermore, in our algorithm we apply parallelism to transverse different sections of the input strings concurrently, speeding up the resulting running time. The algorithm has been successfully used in natural language and biological sequence contexts. 相似文献
57.
Pablo Giménez Benjamín Molina Jaime Calvo-Gallego Manuel Esteve Carlos E. Palau 《Computers in Industry》2014
Sensor Web Enablement (SWE) technologies have been successfully applied to a great variety of outdoor scenarios but, in practical terms, little effort has been applied for indoor environments, and even less in the field of industrial applications. This article presents an intelligent SWE application for an indoor and industrial scenario, with the aim of improving and increasing the levels of human safety. The base low-level architecture is built on top of wireless sensor networks (WSN) connected to a Sensor Observation Service (SOS). Higher layers in the architecture include services that make real time decisions based on the collected data. Both simulation and experimental results are presented. The paper shows the viability of our approach in terms of performance, scalability, modularity and safety. 相似文献
58.
Towards an Environmentally Acceptable Heterogeneous Catalytic Method of Producing Adipic Acid by the Oxidation of Hydrocarbons in Air 总被引:1,自引:0,他引:1
Raja Robert Lee Sang-Ok Sanchez-Sanchez Manuel Sankar Gopinathan Harris Kenneth D.M. Johnson Brian F.G. Thomas John Meurig 《Topics in Catalysis》2002,20(1-4):85-88
A survey is given of the catalytic methods potentially available for the production of adipic acid by the oxidation of readily available hydrocarbon precursors under environmentally benign conditions. Encouraging results are reported using H2O2 as oxidant and microporous FeAlPO-5 as catalyst at moderate temperatures. 相似文献
59.
Ana Paula Vieira Soares Manuel Farinha Portela Alain Kiennemann 《Catalysis Reviews》2005,47(1):125-174
This review deals with the important industrial reaction of formaldehyde manufacture by methanol oxidation over iron molybdate catalysts. Detailed reference is made to the used catalyst, preparation techniques (coprecipitation, sol-gel like, mechanical mixing, etc.) including unsupported and supported catalysts, promoters and characterization methods. The controversial active phase assignment (stoichiometric versus Mo rich iron molybdate) is discussed. The proposed reaction mechanisms and kinetic laws for the main and side reactions are examined. The catalyst deactivation processes are reviewed and the role of Mo excess on these processes is underlined. Finally conclusions and perspectives are presented. 相似文献
60.
Emilio Soto Candela Mario Ortega Pérez Clemente Marín Romero David C. Pérez López Gustavo Salvador Herranz Manuel Contero Mariano Alcañiz Raya 《Multimedia Tools and Applications》2014,70(3):1837-1868
In this paper, a computer vision based interactive multi-touch tabletop system called HumanTop is introduced. HumanTop implements a stereo camera vision subsystem which allows not only an accurate fingertip tracking algorithm but also a precise touch-over-the-working surface detection method. Based on a pair of visible spectra cameras, a novel synchronization circuit makes the camera caption and the image projection independent from each other, providing the minimum basis for the development of computer vision analysis based on visible spectrum cameras without any interference coming from the projector. The assembly of both cameras and the synchronization circuit is not only capable of performing an ad-hoc version of a depth camera, but it also introduces the recognition and tracking of textured planar objects, even when contents are projected over them. On the other hand HumanTop supports the tracking of sheets of paper and ID-code markers. This set of features makes the HumanTop a comprehensive, intuitive and versatile augmented tabletop that provides multitouch interaction with projective augmented reality on any flat surface. As an example to exploit all the capabilities of HumanTop, an educational application has been developed using an augmented book as a launcher to different didactic contents. A pilot study in which 28 fifth graders participated is presented. Results about efficiency, usability/satisfaction and motivation are provided. These results suggest that HumanTop is an interesting platform for the development of educational contents. 相似文献