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1.
Fbio Gomes Costa Elias Andrade Braga Soraia Teixeira Brando Alexandre de Freitas Espeleta Zênis Novais da Rocha Lílian Maria Tosta Simplício Emerson Andrade Sales 《Applied Catalysis A: General》2005,290(1-2):221-226
Infrared and UV–vis studies of metallocene immobilization on silica are reported here. The results have indicated changes in the Zr coordination sphere of metallocene depending on the immobilization route used. The reaction of [(Cp)2ZrCl2] with silica formed [(Cp)2ZrCl]+[SiO]− species. The same metallocene, reacting with TMA modified silica, formed monomethylated and dimethylated species by the substitution of chloro for methyl ligands, stabilized on the surface by interaction with “MAO-like” species (methylaluminoxane, MAO). These monomethylated and dimethylated cationic zirconium species are the active centers for the polymerization reaction. Different order of TMA addition in the silica modification step generated surface species of a similar nature, differing in their relative quantities. The highest amount of these active species was obtained when the support was added to the TMA solution rather than adding the TMA solution to the silica support. This was the most significant parameter affecting catalytic activity in ethylene polymerization. 相似文献
2.
In this paper we discuss about geographic representations as a basis for describing, organizing, accessing and understanding heterogeneous shared information on the web. Maps are popular on the web, because of the reference to space, the most important domain of human experience, the proliferation of location aware devices and services and the availability of a set of tools that enable an heterogeneous population of users to explore and even modify these representations.Metaphorical maps, representing concepts and relations of a specific knowledge domain with symbols taken from another well known and widely used domain, couple the benefits of cartographic representation with the power and intuitiveness of the metaphor, permitting the communication and sharing of such knowledge.We introduce a classification of maps based on antinomies between real and imaginary worlds, and between direct and metaphoric knowledge; we argue that cartography can be used as a visual language for organizing and sharing knowledge related to different semantic domains, supporting our arguments with examples. Finally, we define a set of functions and related data structures able to support a user in browsing cartographic representations using state-of-art tools and systems available on the web. 相似文献
3.
Evandro Eduardo Broday Antonio Augusto de Paula XavierReginaldo de Oliveira 《International Journal of Industrial Ergonomics》2014
The incorrect determination of metabolic rate can be linked to discrepancies between the model of the PMV (Predicted Mean Vote) and real thermal sensation collected in field studies. Aiming to improve the correlation of the PMV model and the real thermal sensation, this work established new values for the metabolic rate: one way being called “calculated” using Newton's Method and the other called "measured" using a metabolic analyzer. Welder's activities were evaluated, through the measurements of environmental and personal variables. New values of metabolic rate were determined for this activity. The values found for the calculated form and the measured one were, respectively, 178.63 and 145.46 W/m2, different from the range provided by the table of ISO 8996 (2004) for this activity (75–125 W/m2). In order to verify which of the values of the metabolic rate was closer to the real thermal sensation of PMV, a linear regression was made between the PMV and the real thermal sensation in three ways: S × PMVtabulated (R2 = 0.1749), S × PMVcalculated (R ² = 0.7481) and S × PMVmeasured (R2 = 0.7854). It was found that the values measured by the instrument gave a higher coefficient of determination which was chosen for the correction of the table. The correction of the table provides a value of Mpredicted, that is a value of metabolic rate that corrects the values provided by the tables of ISO 8996 (2004), by means of a correction coefficient. For the welder's activities in a metal-mechanics industry, tabulated values can be multiplied by the correction coefficient 1.4648 in order to minimize inaccuracies. The PMVpredicted, obtained through the Mpredicted, when related to the actual thermal sensation, provides a coefficient of determination of 0.7511, thereby improving the model of the PMV. 相似文献
4.
Clinical practice guidelines in paper format are still the preferred form of delivery of medical knowledge and recommendations to healthcare professionals. Their current support and development process have well identified limitations to which the healthcare community has been continuously searching solutions. Artificial intelligence may create the conditions and provide the tools to address many, if not all, of these limitations.. This paper presents a comprehensive and up to date review of computer-interpretable guideline approaches, namely Arden Syntax, GLIF, PROforma, Asbru, GLARE and SAGE. It also provides an assessment of how well these approaches respond to the challenges posed by paper-based guidelines and addresses topics of Artificial intelligence that could provide a solution to the shortcomings of clinical guidelines. Among the topics addressed by this paper are expert systems, case-based reasoning, medical ontologies and reasoning under uncertainty, with a special focus on methodologies for assessing quality of information when managing incomplete information. Finally, an analysis is made of the fundamental requirements of a guideline model and the importance that standard terminologies and models for clinical data have in the semantic and syntactic interoperability between a guideline execution engine and the software tools used in clinical settings. It is also proposed a line of research that includes the development of an ontology for clinical practice guidelines and a decision model for a guideline-based expert system that manages non-compliance with clinical guidelines and uncertainty. 相似文献
5.
L. A. Gioielli R. N. M. Pitombo M. Vitolo R. Baruffaldi M. N. Oliveira M. S. Augusto 《Journal of the American Oil Chemists' Society》1994,71(6):579-582
The lipase-catalyzed interesterification of oils and fats gives products that are unobtainable by chemical interesterification
methods. Acidolysis of babassu fat and palmitic acid, catalyzed by immobilized lipase (Lipozyme; Novo Industri, Bagsveard,
Denmark), was studied. The reactions were performed at 65°C with 5% w/w enzyme for 4 h. The molar proportions of babassu fat/palmitic
acid were 1∶0.1, 1∶0.3 and 1∶0.5. At the end of the reaction period, the catalyst particles were removed by filtration, and
the residual oil was extracted with organic solvent (diethyl ether). The recovered particles were then reused. The palmitic
acid content of babassu fat before and after acidolysis changed from 10 to 22% at a molar proportion of 1∶0.5. The equilibrium
was attained in about 4 h. The original water and enzymatic activities of Lipozyme were maintained after acidolysis. Water
sorption isotherms of the immobilized enzyme were determined at 25, 35 and 45°C. From the temperature dependence of the isotherms,
isosteric heats of sorption were evaluated by means of the Clausius Clapeyron equation. Monolayer moisture content was calculated
by means of the B.E.T. and Guggenhein-Anderson-De Boer analyses.
Paper presented at the International Meeting on Fats and Oils Technology, Universidade Estadual de Campinas, Brazil, 1991. 相似文献
6.
Augusto Lanzón Tomás Albi Arturo Cert Jaime Gracián 《Journal of the American Oil Chemists' Society》1994,71(3):285-291
In numerous Spanish virgin olive oils, 6,10-dimethyl-1-undecene, various sesquiterpenes, the series ofn-alkanes from C14 to C35, n-8-heptadecene and squalene are the only less volatile components detected by gas chromatography
in the hydrocarbon fraction. In oils from olives of the Arbequine variety, a series ofn-9-alkenes has also been found. In refined oils, notable features are the absence of the most volatile compounds and the appearance
of other hydrocarbons produced during the refining process. Among these,n-alkanes, alkadienes (mainlyn-hexacosadiene), stigmasta-3,5-diene, isomerization products of squalene, isoprenoidal polyolefins coming from hydroxy derivatives
of squalene and steroidal hydrocarbons derived from 24-methylene cycloartanol were identified. Physical refining produces
larger amounts of degradation products and greater losses ofn-alkanes than chemical processing. Squalene is the major hydrocarbon component in all oils, both virgin and refined. The ranges
of concentration for the different hydrocarbons found in Spanish virgin olive oils are presented. 相似文献
7.
Stephen J. Walsh Amy L. McCleary Carlos F. Mena Yang Shao Julie P. Tuttle Augusto Gonzlez Rachel Atkinson 《Remote sensing of environment》2008,112(5):291-1941
In the Galapagos Islands of Ecuador, one of the greatest threats to the terrestrial ecosystem is the increasing number and areal extent of invasive species. Increased human presence on the islands has hastened the introduction of plant and animal species that threaten the native and endemic flora and fauna. Considerable research on invasive species in the Galapagos Islands has been conducted by the Charles Darwin Foundation. We complement that work through a spatially- and spectrally-explicit satellite assessment of an important invasive plant species (Psidium guajava — guava) on Isabela Island that integrates diverse remote sensing systems, data types, spatial and spectral resolutions, and analytical and image processing approaches. QuickBird and Hyperion satellite data are processed to characterize the areal extent and spatial structure of guava through the following approaches: (1) QuickBird data are classified through a traditional pixel-based approach (i.e., an unsupervised classification approach using the ISODATA algorithm), as well as an Object-Based Image Analysis (OBIA) approach; (2) multiple approaches for spectral “unmixing” of the Hyperion hyper-spectral data are assessed to construct spectral end-members from QuickBird data using linear and non-linear mixture modeling approaches; and (3) landscape pattern metrics are calculated and compared for the pixel-based, object-based, and spectral unmixing approaches. The spectral–spatial characteristics of guava are interpreted relative to management strategies for the control of guava and the restoration of natural ecosystems in the Galapagos National Park. 相似文献
8.
Daniele Di Gioacchino Nicola Poccia Martijn Lankhorst Claudio Gatti Bruno Buonomo Luca Foggetta Augusto Marcelli Hans Hilgenkamp 《Journal of Superconductivity and Novel Magnetism》2017,30(2):359-363
The current frontiers in the investigation of high-energy particles demand for new detection methods. Higher sensitivity to low-energy deposition, high-energy resolution to identify events and improve the background rejection, and large detector masses have to be developed to detect even an individual particle that weakly interacts with ordinary matter. Here, we will describe the concept and the layout of a novel superconducting proximity array which show dynamic vortex Mott insulator to metal transitions, as an ultra-sensitive compact radiation-particle detector. 相似文献
9.
George André Tonini Luís Augusto Martins Ruotolo 《Clean Technologies and Environmental Policy》2017,19(2):403-415
Heavy metal removal from industrial wastewaters has been intensively studied, since it is well known that they can cause severe problems to human health and aquatic life, even at very low concentrations. In this work, it was demonstrated that electrodeposition in fluidized bed electrode (FBE) can be efficiently employed to remove metal ions from solution, avoid contamination, and recover the metal. Copper electrodeposition from diluted solutions was efficiently performed using a membraneless FBE. The average current efficiency (ACE), average energy consumption (AEC), and space–time yield (AY) was optimized taking into account the operational and process variables. It was noted that for all response variables studied, the raise of supporting electrolyte concentration (C s) contributed to improvements in the process. The operational conditions current (I) and bed expansion (E) determined the values of CE, Y, and EC under activated control, but the initial copper concentration (C 0) determined how long the electrodeposition process will work under activated or mass transfer control, thus affecting the average values of CE, Y, and EC. Considering C 0 of 500 mg L?1, copper can be optimally recovered with ACE >60 %, AY >38 kg h?1 m?3, and AEC <4.0 kWh kg?1 by applying the lowest I and the highest levels of E and C s. It was concluded that the electrochemical technology using a membraneless FBE reactor is economically competitive and be applied for the treatment of wastewaters contaminated with copper or other metals. 相似文献
10.
José Augusto de Oliveira Diogo Aparecido Lopes Silva Mariana Guardia Lillian do Nascimento Gambi Otávio José de Oliveira Aldo Roberto Ometto 《Clean Technologies and Environmental Policy》2017,19(6):1761-1774
The companies’ needs to adopt changes in their way of production to maximize the environmental performance required by their stakeholders, and at the same time, to maximize their economic and market performance, have made them seek for environmental strategies and certifications. In this sense, the Cleaner Production and the Environmental Management System based on ISO 14001 have been, respectively, presented, since the main objective of this research is to identify and analyze Cleaner Production contributions to comply with ISO 14001 requirements. For such, a survey research has been carried out in Brazilian industrial companies certified by ISO 14001. We have identified the main performance factors by leading practices and variables of Cleaner Production that contribute to the compliance with the standard requirements by companies. Thus, it has been noted that Cleaner Production is an important strategy for the preparation of companies for certification as well as for improving their environmental performance. 相似文献