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121.
122.
Thermodynamic studies of a HAT cycle and its components 总被引:1,自引:0,他引:1
The electric power grid contains more and more renewable power production such as wind and solar power. The use of renewable power sources increases the fluctuations in the power grid which increase the demand for highly efficient, fast-starting power-producing units that can cope with sudden production losses. One of the more innovative power plant cycles, that have the potential of competing with conventional combined power plants in efficiency but has a higher availability and faster start up time, is the Evaporative Gas Turbine (EvGT) or Humid Air Turbine (HAT). A thermodynamic evaluation of different HAT cycle layouts has been done in this paper. Each layout is evaluated separately which makes it possible to study different components individual contribution to the efficiency and specific power. The thermodynamic evaluation also shows that it is important to look at different cool-flow extracting positions. The effect of water temperature entering the cycle, called make-up water, and where it is introduced into the cycle has been evaluated. The make-up water temperature also affects the optimal pressure level for intercooling and it is shown that an optimal position can be decided considering design parameters of the compressor and the water circuit. 相似文献
123.
Martin Oschatz Marcus Rose Nicole Klein Thomas Freudenberg Gleb Yushin 《Carbon》2010,48(14):3987-3992
A hierarchical and highly porous carbide-derived carbon (CDC) was obtained by nanocasting of pre-ceramic precursors into cubic ordered silica (KIT-6) and subsequent chlorination. Resulting CDC replica materials show high methane and n-butane uptake and excellent performance as electrode materials in supercapacitors. 相似文献
124.
Ruscio John; Walters Glenn D.; Marcus David K.; Kaczetow Walter 《Canadian Metallurgical Quarterly》2010,22(1):5
A number of recent studies have used Meehl’s (1995) taxometric method to determine empirically whether one should model assessment-related constructs as categories or dimensions. The taxometric method includes multiple data-analytic procedures designed to check the consistency of results. The goal is to differentiate between strong evidence of categorical structure, strong evidence of dimensional structure, and ambiguous evidence that suggests withholding judgment. Many taxometric consistency tests have been proposed, but their use has not been operationalized and studied rigorously. What tests should be performed, how should results be combined, and what thresholds should be applied? We present an approach to consistency testing that builds on prior work demonstrating that parallel analyses of categorical and dimensional comparison data provide an accurate index of the relative fit of competing structural models. Using a large simulation study spanning a wide range of data conditions, we examine many critical elements of this approach. The results provide empirical support for what marks the first rigorous operationalization of consistency testing. We discuss and empirically illustrate guidelines for implementing this approach and suggest avenues for future research to extend the practice of consistency testing to other techniques for modeling latent variables in the realm of psychological assessment. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
125.
Marcus Knauf 《Holz als Roh- und Werkstoff》2017,75(4):639-649
This article presents an explorative study analyzing the market potential for timber-concrete composites (TCC) in the German construction industry. Data from official statistics on building activity in Germany for 2014 and the period from 2010 to 2014 were evaluated in the analysis, and interviews with expert architects and planners were conducted. The goal of the study is to explore the market opportunities of TCC. The experts who were questioned consider TCC as the key to opening the market for types of buildings in which timber construction has had limited application until now (multi-family houses and residential-like/multi-story non-residential buildings). Possible market potentials are calculated with the aid of a scenario which can also be adapted in the context of individual scenarios based on the given data. The study makes it clear that TCC is not only to be evaluated technologically (R + D, standards etc.); market development depends at least as much on soft (social) factors. In part, this concerns the identity of timber construction itself, which must deconstruct the mindsets that have formed over decades in the wood-based sector and are communicated in marketing. At the same time, a co-operation between concrete and timber constructors becomes necessary, which experts call a “clash of cultures.” 相似文献
126.
Guido Berning Marcus Brandenburg Korhan Gürsoy Vipul Mehta Franz-Josef Tölle 《OR Spectrum》2002,24(4):371-401
This paper considers a complex scheduling problem in the chemical process industry involving batch production. The application
described comprises a network of production plants with interdependent production schedules, multi-stage production at multi-purpose
facilities, and chain production. The paper addresses three distinct aspects: (i) a scheduling solution obtained from a genetic algorithm based optimizer, (ii) a mechanism for collaborative planning among the involved plants, and (iii) a tool for manual updates and schedule changes. The tailor made optimization algorithm simultaneously considers alternative
production paths and facility selection as well as product and resource specific parameters such as batch sizes, and setup
and cleanup times. The collaborative planning concept allows all the plants to work simultaneously as partners in a supply
chain resulting in higher transparency, greater flexibility, and reduced response time as a whole. The user interface supports
monitoring production schedules graphically and provides custom-built utilities for manual changes to the production schedule,
investigation of various what-if scenarios, and marketing queries.
RID="*"
ID="*" The authors would like to thank Hans-Otto Günther and Roland Heilmann for helpful comments on draft versions of this
paper. 相似文献
127.
Marcus E. Markiewicz Carlos J.P. Lucena Paulo S.C. Alencar Donald D. Cowan 《Annals of Software Engineering》2002,13(1-4):111-140
Separation of concerns is a well-established principle in software engineering that supports reuse by hiding complexity through abstraction mechanisms. The Abstract Design Views model was created with reuse in mind and allows the designer to apply separation of concerns in a software system from the design to the implementation. In this model, viewed objects represent the basic concern, i.e., the algorithms that provide the essential functionality relevant to an application domain, and viewer objects represent the special concerns related to other software issues, such as user interface presentation, synchronization, and timing. In this paper we use a reuse taxonomy to analyze and validate this model. Using this analysis and the properties of the relationship between viewer and viewed objects, called views, we also indicate how to map the views-based designs into implementations based on design patterns that satisfy the views properties. Finally, we show how to apply the principles of our approach, using views and the design patterns, to design e-commerce applications. 相似文献
128.
129.
Marco Zaffalon Marcus Hutter 《Annals of Mathematics and Artificial Intelligence》2005,45(1-2):215-239
This paper is concerned with the reliable inference of optimal tree-approximations to the dependency structure of an unknown
distribution generating data. The traditional approach to the problem measures the dependency strength between random variables
by the index called mutual information. In this paper reliability is achieved by Walley's imprecise Dirichlet model, which generalizes Bayesian learning with Dirichlet priors. Adopting the imprecise Dirichlet model results in posterior interval
expectation for mutual information, and in a set of plausible trees consistent with the data. Reliable inference about the
actual tree is achieved by focusing on the substructure common to all the plausible trees. We develop an exact algorithm that
infers the substructure in time O(m
4), m being the number of random variables. The new algorithm is applied to a set of data sampled from a known distribution. The
method is shown to reliably infer edges of the actual tree even when the data are very scarce, unlike the traditional approach.
Finally, we provide lower and upper credibility limits for mutual information under the imprecise Dirichlet model. These enable
the previous developments to be extended to a full inferential method for trees. 相似文献
130.
In this paper we describe two projects on contextualized computer systems and audio augmented environments we are currently
working on at the Fraunhofer Institutes FIT and IMK. In this paper we will only focus on the world models and the augmentation
layer. Both projects are based on completely different technologies, and use different representation methods and interaction
facilities. While in hippie users are moving with small laptop computers or wearable computers with a small visual display,
in LISTEN users will have only a wireless headphone displaying spatially rendered sound-scenes.
Correspondence to: J. Goβmann, Fraunhofer-IMK, Schloss Birlinghoven, D-53754 St Augustin, Germany. 相似文献