864 resultados para Content syndication


Relevância:

20.00% 20.00%

Publicador:

Resumo:

In this paper we describe the electrosynthesis of poly[(2-bromo-5-hexyloxy- 1,4-phenylenevinylene)-co-(1,4-phenylenevinylene)] (BHPPV-co-PPV), a novel conducting copolymer, and its application as active layer of a chemiresistive gas sensor suitable for quantification of ethanol present in ethanol-gasoline mixtures normally present in the fuel tanks of flex-fuel vehicles. This information is crucial for the smooth operation of the engine since it permits optimal air:fuel ratio regulation. The sensor consists of an interdigitated electrode coated with a thin polymer film doped with dodecylbenzenesulfonic acid. On exposure to fuel vapours at room temperature, the device presents a linear correlation between its electrical conductance and the ethanol concentration in the fuel. (C) 2008 Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The oxygen reduction reaction (ORR) was investigated on carbon-supported Pt-Co nanoparticle electrocatalysts with low Pt content in alkaline electrolyte. High resolution transmission electron microscopy, In situ X-ray absorption spectroscopy, and X-ray diffraction analysis evidenced large structural differences of the Pt-Co particles depending oil the route of the catalyst synthesis. It was demonstrated that although the Pt-Co materials contain low amounts of Pt, they show very good activities when the particles are formed by a Pt-rich shell and a Pt-Co core, which was obtained after submitting the electrocatalyst to a potential cycling in acid electrolyte. The high activity of this material was due to a major contribution from its higher surface area, as a result of the leaching of the Co atoms from the particle Surface. Furthermore, its high activity was ascribed to a minor contribution from the electronic interaction of the Pt atoms, at the particle surface, and the Co atoms located in the beneath layer, lowering the Pt cl-band center. As these electrocatalysts presented high activity for the ORR with low Pt content, the cost of the fuel cell cathodes could be lowered considerably. (c) 2009 Elsevier B.V. All rights reserved.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

This presentation was offered as part of the CUNY Library Assessment Conference, Reinventing Libraries: Reinventing Assessment, held at the City University of New York in June 2014.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

The Thesis focused on hardware based Load balancing solution of web traffic through a load balancer F5 content switch. In this project, the implemented scenario for distributing HTTPtraffic load is based on different CPU usages (processing speed) of multiple member servers.Two widely used load balancing algorithms Round Robin (RR) and Ratio model (weighted Round Robin) are implemented through F5 load balancer. For evaluating the performance of F5 content switch, some experimental tests has been taken on implemented scenarios using RR and Ratio model load balancing algorithms. The performance is examined in terms of throughput (bits/sec) and Response time of member servers in a load balancing pool. From these experiments we have observed that Ratio Model load balancing algorithm is most suitable in the environment of load balancing servers with different CPU usages as it allows assigning the weight according to CPU usage both in static and dynamic load balancing of servers.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

A dislocation model, accurately describing the uniaxial plastic stress-strain behavior of dual phase (DP) steels, is proposed and the impact of martensite content and ferrite grain size in four commercially produced DP steels is analyzed. It is assumed that the plastic deformation process is localized to the ferrite. This is taken into account by introducing a non-homogeneity parameter, f(e), that specifies the volume fraction of ferrite taking active part in the plastic deformation process. It is found that the larger the martensite content the smaller the initial volume fraction of active ferrite which yields a higher initial deformation hardening rate. This explains the high energy absorbing capacity of DP steels with high volume fractions of martensite. Further, the effect of ferrite grain size strengthening in DP steels is important. The flow stress grain size sensitivity for DP steels is observed to be 7 times larger than that for single phase ferrite.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

There is a lack of research on the everyday lives of older people in developing countries. This exploratory study used structured observation and content analysis to examine the presence of older people in public fora, and considered the methods’ potential for understanding older people’s social integration and inclusion. Structured observation occurred of public social spaces in six cities each located in a different developing country, and in one city in the United Kingdom, together with content analysis of the presence of people in newspaper pictures and on television in the selected countries. Results indicated that across all fieldwork sites and data sources, there was a low presence of older people, with women considerably less present than men in developing countries. There was variation across fieldwork sites in older people’s presence by place and time of day, and in their accompanied status. The presence of older people in images drawn from newspapers was associated with the news/non-news nature of the source. The utility of the study’s methodological approach is considered, as is the degree to which the presence of older people in public fora might relate to social integration and inclusion in different cultural contexts.

Relevância:

20.00% 20.00%

Publicador:

Resumo:

Mercury contamination of food products results from contact with soil, water, and air polluted with mercury from industrial sources, as well as from the use of mercury-containing pesticides and fungicides on plants. A method was developed for extracting mercury from tobacco products. The mercury content of various tobacco products was determined, using an atomic absorption spectrophotometer.