Constrained Networks
Mostrando 13-24 de 24 artigos, teses e dissertações.
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13. Energy and capital targets for constrained heat exchanger networks
A new procedure for estimating area and capital cost targets of constrained heat exchanger networks is presented. The method allows for match constrained networks and exchangers with more than one tube pass. The procedure is based on modelling the problem as a non-linear formulation where the forbidden exchanger matches are included as constraints and the te
Brazilian Journal of Chemical Engineering. Publicado em: 2000-12
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14. Aspectos operacionais e estruturais em "retrofit" de redes de trocadores de calor
The study of retrofit procedures for heat exchanger networks has been subject of numerous research work, due to its importance in inergy-saving policies in chemical processes. Early work focused on the cost (and area) estimation of the additional exchangers required to achieve the new process conditions, without considering the layout of the existing network
Publicado em: 1999
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15. Contribuição ao estudo das coberturas penseis
This work presents a finite element approach to static and dynamic analysis of counterstressed cable structures. Two nodes, constant strain finite elements are used to model hanging cables, plane prestressed cable trusses and 3-D prestressed cable networks. The two nodes elements are assembled with tniss, beam and frame elements to the static analysis or mix
Publicado em: 1991
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16. The adaptive nature of the human neurocognitive architecture: An alternative model
The model of the human neurocognitive architecture proposed by evolutionary psychologists is based on the presumption that the demands of hunter-gatherer life generated a vast array of cognitive adaptations. Here we present an alternative model. We argue that the problems inherent in the biological markets of ancestral hominids and their mammalian predecesso
The National Academy of Sciences.
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17. Degree dependence in rates of transcription factor evolution explains the unusual structure of transcription networks
Transcription networks have an unusual structure. In both prokaryotes and eukaryotes, the number of target genes regulated by each transcription factor, its out-degree, follows a broad tailed distribution. By contrast, the number of transcription factors regulating a target gene, its in-degree, follows a much narrower distribution, which has no broad tail. W
The Royal Society.
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18. Mitotic chromosomes are chromatin networks without a mechanically contiguous protein scaffold
Isolated newt (Notophthalmus viridescens) chromosomes were studied by using micromechanical force measurement during nuclease digestion. Micrococcal nuclease and short-recognition-sequence blunt-cutting restriction enzymes first remove the native elastic response of, and then to go on to completely disintegrate, single metaphase newt chromosomes. These exper
National Academy of Sciences.
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19. Integrative Analysis of Cell Cycle Control in Budding YeastD⃞
The adaptive responses of a living cell to internal and external signals are controlled by networks of proteins whose interactions are so complex that the functional integration of the network cannot be comprehended by intuitive reasoning alone. Mathematical modeling, based on biochemical rate equations, provides a rigorous and reliable tool for unraveling t
The American Society for Cell Biology.
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20. Supply–demand balance and metabolic scaling
It is widely accepted that metabolic rates scale across species approximately as the 3/4 power of mass in most if not all groups of organisms. Metabolic demand per unit mass thus decreases as body mass increases. Metabolic rates reflect both the ability of the organism's transport system to deliver metabolites to the tissues and the rate at which the tissues
National Academy of Sciences.
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21. Emergent trade-offs and selection for outbreak frequency in spatial epidemics
Nonspatial theory on pathogen evolution generally predicts selection for maximal number of secondary infections, constrained only by supposed physiological trade-offs between pathogen infectiousness and virulence. Spread of diseases in human populations can, however, exhibit large scale patterns, underlining the need for spatially explicit approaches to path
National Academy of Sciences.
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22. Rapid Sequence Evolution of Transcription Factors Controlling Neuron Differentiation in Caenorhabditis
Whether phenotypic evolution proceeds predominantly through changes in regulatory sequences is a controversial issue in evolutionary genetics. Ample evidence indicates that the evolution of gene regulatory networks via changes in cis-regulatory sequences is an important determinant of phenotypic diversity. However, recent experimental work suggests that the
Oxford University Press.
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23. The origin of intermediary metabolism
The core of intermediary metabolism in autotrophs is the citric acid cycle. In a certain group of chemoautotrophs, the reductive citric acid cycle is an engine of synthesis, taking in CO2 and synthesizing the molecules of the cycle. We have examined the chemistry of a model system of C, H, and O that starts with carbon dioxide and reductants and uses redox c
The National Academy of Sciences.
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24. A Gα-dependent pathway that antagonizes multiple chemoattractant responses that regulate directional cell movement
Chemotactic cells, including neutrophils and Dictyostelium discoideum, orient and move directionally in very shallow chemical gradients. As cells polarize, distinct structural and signaling components become spatially constrained to the leading edge or rear of the cell. It has been suggested that complex feedback loops that function downstream of receptor si
Cold Spring Harbor Laboratory Press.