Using what we know: Consequences of intentionally retrieving gist versus item-specific information.

The effect of a prior gist-based versus item-specific retrieval orientation on recognition of objects and words was examined. Prior item-specific retrieval increased item-specific recognition of episodically related but not previously tested objects relative to both conceptual- and perceptual-gist retrieval. An item-specific retrieval advantage also was found when the stimuli were words (synonyms) rather than objects but not when participants overtly named objects during gist-based recognition testing, which suggests that they did not always label objects under general gist-retrieval instructions. Unlike verbal overshadowing, labeling objects during recognition attenuated (but did not eliminate) test- and interference-related forgetting. A full understanding of how retrieval affects subsequent memory, even for events or facts that are not themselves retrieved, must take into account the specificity with which that retrieval occurs. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

An analytical model for the combustion of coal particles

A model for the combustion of coal particles is developed which accounts for the gasification and pyrolysis reactions throughout the particles, oxidation reactions at the particles' outer surface, distributed gas-phase reactions around the particles, and transport of heat and mass throughout the reaction zones. The model shows that the combustion of large particles is dominated by gasification and gas-phase reactions. As large particles burn and shrink, however, the mechanism changes to one dominated by surface oxidation. This change in mechanism can be gradual or very rapid (even discontinuous) depending on the combustion conditions. The particle size at which this transition takes place decreases as the bulk gas temperature or oxygen concentration increase. The proposed model is used to predict the conversion of pulverized coal as a function of time; the results agree with literature data for particles of 26-32 μm radius.     

Production of UF<Subscript>4</Subscript> From Refinery Scrap Materials

Under the auspices of the AEC the National Lead Co. has endeavored to develop a method of producing uranium from scrap. The authors compare the relative difficulty and cost of the prior operations to their method in addition to a detailed discussion of the present mode of activity.     

Operation, administration, and maintenance in MPLS networks

The boundaries between packet and circuit networks have long disappeared, with many traditional circuit-switched applications such as voice and video now being carried over packet-switched IP/MPLS or Ethernet networks. However, this transition has happened so fast that many OAM functions supported by circuit-switched networks such as SONET/SDH are still unmatched in packet networks. In order to match the quality sustained by circuit-switched networks, OAM functions must also be developed for such packet networks. A number of recent efforts have started to address OAM functions for IP/MPLS and Ethernet packet technologies. Service providers and carriers alike are the driving force behind the work, as there is general recognition that to generate sustained revenues, services must be efficiently managed. In this article we discuss issues in providing OAM features and capabilities for MPLS-based packet networks.     

One Year Operating Experience of Large Electrochemical SCR Rectifiers

After more than one year of successful operation, the design and performance of a 52.5 MW thyristor controlled rectifier installation in a chlor-alkali plant are reviewed. Procedures for final checkout of the installation before plant startup as well as field modifications made to the equipment are discussed. Maintenance procedures are outlined and advantages of thyristor controlled rectifiers are detailed. Power factor and harmonic considerations are also presented.     

Operation, administration, and maintenance of Ethernet services in wide area networks

Recent developments in Ethernet technology, such as 10G Ethernet interfaces, Ethernet passive optical networks, and resilient packet rings are pushing Ethernet from the local area network environment to metropolitan and wide area network environments. For Ethernet service providers, managing Ethernet services efficiently is key to a sustainable business model. This article discusses issues in providing OAM features and capabilities to Ethernet services over metro and wide area networks. We analyze current Ethernet features that can be leveraged in an Ethernet OAM framework, and introduce requirements and new functionalities to support Ethernet services in wide area networks.     

Substructured macro elements based on locally blended interpolation

In this paper we describe a new class of locally refined macro finite elements which are especially amenable to the use of substructuring techniques for the efficient solution of the resulting idealization. The tools and guidelines illustrated by the examples of modelling crack tips, point load singularities and singularities at re-entrant corners should enable an analyst to construct other such blended macro elements specifically tailored to his particular class of problems. The use of such substructured macro elements in finite element calculations permits substantial reduction in the manual effort of data preparation and the computational cost of numerical solution.     

A control theoretical approach to congestion control in packet networks

In this paper, we introduce a control theoretical analysis of the closed-loop congestion control problem in packet networks. The control theoretical approach is used in a proportional rate controller, where packets are admitted into the network in accordance with network buffer occupancy. A Smith Predictor is used to deal with large propagation delays, common to high speed backbone networks. The analytical approach leads to accurate predictions regarding both transients as well as steady-state behavior of buffers and input rates. Moreover, it exposes tradeoffs regarding buffer dimensioning, packet loss, and throughput.     

A new class of transitional blended finite elements for the analysis of solid structures

Recently developed computer aided design systems for the design and modification of complex physical solids using interactive computer graphics offer the exciting possibility of an integrated design/analysis system. Called geometric modellers, these systems build complex solids from primitive solids (cubes, cylinders, spheres, etc.) and macro solids (combinations of primitives). To provide an effective finite element analysis capability for these systems, methods must be devised to ease the burden of discretizing the solid geometry into a user controlled finite element mesh. In this paper we describe a new class of transitional blended finite elements which make substantially simpler the task of finite element mesh generation and local mesh refinement. Computational experience indicates that numerical accuracy is not compromised by use of these flexible elements.