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71.
The numerical analysis of thermoacoustic oscillation phenomena by means of time-dependent CFD simulations usually requires a great computational effort, which may not be reasonable in industrial design. On the other hand, CFD tools provide the only approach that includes all the physical and chemical aspects involved in the thermoacoustic coupling between flame heat release and the acoustic modes of the burner/combustion chamber system. This paper presents some guidelines to reduce the computational effort required to perform a CFD analysis of the thermoacoustic oscillations with commercial codes. These guidelines are organized in a procedure that can be followed to analyze thermoacoustic coupling conditions that actually lead to unstable oscillations or are identified as potentially critical in the design phase. This procedure is also illustrated by an example of application, the partially-premixed flame type burner of a real 10 MW industrial boiler which shows noisy pressure fluctuations at a low frequency. 相似文献
72.
Carlos Colman-Meixner Ferhat Dikbiyik M. Farhan Habib Massimo Tornatore Chen-Nee Chuah Biswanath Mukherjee 《Photonic Network Communications》2014,27(3):141-153
Cloud-computing services are provided to consumers through a network of servers and network equipment. Cloud-network (CN) providers virtualize resources [e.g., virtual machine (VM) and virtual network (VN)] for efficient and secure resource allocation. Disasters are one of the worst threats for CNs as they can cause massive disruptions and CN disconnection. A disaster may also induce post-disaster correlated, cascading failures which can disconnect more CNs. Survivable virtual-network embedding (SVNE) approaches have been studied to protect VNs against single physical-link/-node and dual physical-link failures in communication infrastructure, but massive disruptions due to a disaster and their consequences can make SVNE approaches insufficient to guarantee cloud-computing survivability. In this work, we study the problem of survivable CN mapping from disaster. We consider risk assessment, VM backup location, and post-disaster survivability to reduce the risk of failure and probability of CN disconnection and the penalty paid by operators due to loss of capacity. We formulate the proposed approach as an integer linear program and study two scenarios: a natural disaster, e.g., earthquake and a human-made disaster, e.g., weapons-of-mass-destruction attack. Our illustrative examples show that our approach reduces the risk of CN disconnection and penalty up to 90 % compared with a baseline CN mapping approach and increases the CN survivability up to 100 % in both scenarios. 相似文献
73.
Roberta Ansuini Roberto Larghetti Alberto Giretti Massimo Lemma 《Energy and Buildings》2011,43(11):3019-3026
The control of indoor thermal comfort in buildings through thermal inertia during the summer season plays a fundamental role in the design of energy efficient buildings, especially in the Mediterranean climate. In fact, lightweight, highly insulated buildings cannot provide the necessary mass to buffer thermal gains. Phase change materials (PCM) have been used to provide lightweight building components with the required thermal inertia without increasing their overall mass. So far the integration of PCM into lightweight piped radiant floors for the control of thermal comfort during summer cooling regimes has not been investigated. This paper reports the development of a lightweight piped radiant floor prototype with an integrated PCM layer aimed at buffering internal gains at constant temperature during summer cooling regimes without affecting its winter warming capacity. Both the construction of the laboratory specimens and the development of the optimized finite element models are detailed and the assessment of the floor performance in a simulated room is discussed. 相似文献
74.
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76.
The Rovereto Emotion and Cooperation Corpus (RECC) is a new resource collected to investigate the relationship between cooperation
and emotions in an interactive setting. Previous attempts at collecting corpora to study emotions have shown that this data
are often quite difficult to classify and analyse, and coding schemes to analyse emotions are often found not to be reliable.
We collected a corpus of task-oriented (MapTask-style) dialogues in Italian, in which the segments of emotional interest are
identified using psycho-physiological indexes (Heart Rate and Galvanic Skin Conductance) which are highly reliable. We then
annotated these segments in accordance with novel multimodal annotation schemes for cooperation (in terms of effort) and facial
expressions (an indicator of emotional state). High agreement was obtained among coders on all the features. The RECC corpus
is to our knowledge the first resource with psycho-physiological data aligned with verbal and nonverbal behaviour data. 相似文献
77.
78.
Michele Dei Nicolò Nizza Massimo Piotto Paolo Bruschi 《Analog Integrated Circuits and Signal Processing》2009,58(1):43-47
A compact voltage controlled CMOS current divider is presented. Differently from previous implementations, exploiting the
MOSFET translinear characteristics in subthreshold region, the proposed circuit is based on devices operating from moderate
to strong inversion. An input current linearity range of nearly a decade is obtained by compensating for the deviations from
the ideal drain current square-law approximation through an original empirical approach. The circuit is suitable for use as
a building block in analog multipliers and for transconductor continuous tuning. The effectiveness of the proposed configuration
is demonstrated by means of electrical simulations, performed on a prototype designed with a commercial process. The robustness
of the linearization algorithm with respect to temperature variations is proven. 相似文献
79.
Stefano Mercati Massimo MilaniLuca Montorsi Fabrizio Paltrinieri 《International Journal of Hydrogen Energy》2013
The working cycle of a novel hydrogen and power generation system based on aluminum combustion with water is analyzed in order to evaluate the best performance in terms of energy conversion efficiency. The system exploits the exothermic reaction between aluminum and steam and produces thermal power for a super-heated steam cycle and hydrogen as a by-product of the reaction. 相似文献
80.
Massimo Merro 《Information and Computation》2009,207(2):194-208
We propose a process calculus to study the behavioural theory of Mobile Ad Hoc Networks. The operational semantics of our calculus is given both in terms of a Reduction Semantics and in terms of a Labelled Transition Semantics. We prove that the two semantics coincide. The labelled transition system is then used to derive the notions of (weak) simulation and bisimulation for ad hoc networks. The labelled bisimilarity completely characterises reduction barbed congruence, a standard branching-time and contextually-defined program equivalence. We then use our (bi)simulation proof method to formally prove a number of non-trivial properties of ad hoc networks. 相似文献