1,327 research outputs found
Development and Verification for the Control Method Using Surplus Pressure of Primary Pumps in Chiller Plant Systems for Air Conditioning which Adopts Primary/Secondary Piping Systems PPT
The primary/secondary piping systems are often employed in large chiller plant Systems.
Normally, the primary flow becomes more than secondary flow, and the flow difference
returns to a chiller via decoupler, which is common to primary flow loop (chiller side) and
secondary flow loop (load side). It is a huge energy loss, because the primary pumps use their
head to lead much flow to the decoupler. Therefore, we have developed new control method
using surplus pressure of the primary pump to reduce the primary and secondary pumps'
energy. In this paper, we used this control method to the actual chiller plant buildings and
verified its effectiveness. As a result, cold water conveyances, both primary loop and
secondary loop, could be covered by only primary pumps during plant operating time, and the
water conveyance power energy was reduced approximately 80%
High-temperature Superconductivity in Layered Nitrides \beta-LiMNCl (M = Ti, Zr, Hf): Insights from Density-functional Theory for Superconductors
We present an ab initio analysis with density functional theory for
superconductors (SCDFT) to understand the superconducting mechanism of doped
layered nitrides \beta-LiMNCl (M=Ti, Zr, and Hf). The current version of
SCDFT is based on the Migdal-Eliashberg theory and has been shown to reproduce
accurately experimental superconducting-transition temperatures Tc of a wide
range of phonon-mediated superconductors. In the present case, however, our
calculated Tc4.3 K (M=Zr) and 10.5 K (M=Hf) are found to be less
than a half of the experimental Tc. In addition, Tc obtained in the present
calculation increases with the doping concentration x, opposite to that
observed in the experiment. Our results indicate that we need to consider some
elements missing in the present SCDFT based on the Migdal-Eliashberg theory.Comment: 18 pages, 13 figures, submitted to Physical Review
Universality of weak selection
Weak selection, which means a phenotype is slightly advantageous over
another, is an important limiting case in evolutionary biology. Recently it has
been introduced into evolutionary game theory. In evolutionary game dynamics,
the probability to be imitated or to reproduce depends on the performance in a
game. The influence of the game on the stochastic dynamics in finite
populations is governed by the intensity of selection. In many models of both
unstructured and structured populations, a key assumption allowing analytical
calculations is weak selection, which means that all individuals perform
approximately equally well. In the weak selection limit many different
microscopic evolutionary models have the same or similar properties. How
universal is weak selection for those microscopic evolutionary processes? We
answer this question by investigating the fixation probability and the average
fixation time not only up to linear, but also up to higher orders in selection
intensity. We find universal higher order expansions, which allow a rescaling
of the selection intensity. With this, we can identify specific models which
violate (linear) weak selection results, such as the one--third rule of
coordination games in finite but large populations.Comment: 12 pages, 3 figures, accepted for publication in Physical Review
A Comprehensive Framework for Human Resources for Health System Development in Fragile and Post-Conflict States
Noriko Fujita and colleagues offer a comprehensive framework for human resource system development, based upon experiences in three fragile and post-conflict health systems: Afghanistan, the Democratic Republic of Congo, and Cambodia
The IEA/ECBCS/Annex 40 Glossary on Commissioning
International Energy Agency's (IEA) Energy Conservation in
Building and Community Systems' (ECBCS) Annex 40 has developed a
glossary of commissioning terms as one of the first commissioning tools
produced within the annex. The glossary consists of four major sections: 1)
definition of basic terms, 2) explanation of basic terms, 3) commissioning
types, and 4) commissioning process. These sections, which were originally
developed to facilitate Annex 40 discussions, are now incorporated into an
on-line database system. This on-line tool is publicly available on the
Annex 40 website and enables users to search for specific definitions and
provides links for more detailed explanations, related terms, and existing
reference definitions. Using this database system many documents
developed in Annex 40 have been actively linked to the glossary for direct
access to the definitions. In addition, during the development and review
process for the glossary, users are able to submit suggestions for new terms,
translations, and other modifications. The purpose of this paper is to
introduce the glossary and database system developed in Annex 40 and to
invite users to participate in the public review of the glossary before
publication of the final report
The Red Rectangle: Its Shaping Mechanism and its Source of Ultraviolet Photons
The proto-planetary Red Rectangle nebula is powered by HD 44179, a
spectroscopic binary (P = 318 d), in which a luminous post-AGB component is the
primary source of both luminosity and current mass loss. Here, we present the
results of a seven-year, eight-orbit spectroscopic monitoring program of HD
44179, designed to uncover new information about the source of the
Lyman/far-ultraviolet continuum in the system as well as the driving mechanism
for the bipolar outflow producing the current nebula. Our observations of the
H-alpha line profile around the orbital phase of superior conjunction reveal
the secondary component to be the origin of the fast (max. v~560^{-1}\sun_{max} \ge 17,0002 -
5\times10^{-5}\sun^{-1}\sun$, about 5% of the
luminosity of the entire system. (abridged)Comment: Accepted for publication in Ap
The surprising negative correlation of gene length and optimal codon use - disentangling translational selection from GC-biased gene conversion in yeast
<p>Abstract</p> <p>Background</p> <p>Surprisingly, in several multi-cellular eukaryotes optimal codon use correlates negatively with gene length. This contrasts with the expectation under selection for translational accuracy. While suggested explanations focus on variation in strength and efficiency of translational selection, it has rarely been noticed that the negative correlation is reported only in organisms whose optimal codons are biased towards codons that end with G or C (-GC). This raises the question whether forces that affect base composition - such as GC-biased gene conversion - contribute to the negative correlation between optimal codon use and gene length.</p> <p>Results</p> <p>Yeast is a good organism to study this as equal numbers of optimal codons end in -GC and -AT and one may hence compare frequencies of optimal GC- with optimal AT-ending codons to disentangle the forces. Results of this study demonstrate in yeast frequencies of GC-ending (optimal AND non-optimal) codons decrease with gene length and increase with recombination. A decrease of GC-ending codons along genes contributes to the negative correlation with gene length. Correlations with recombination and gene expression differentiate between GC-ending and optimal codons, and also substitution patterns support effects of GC-biased gene conversion.</p> <p>Conclusion</p> <p>While the general effect of GC-biased gene conversion is well known, the negative correlation of optimal codon use with gene length has not been considered in this context before. Initiation of gene conversion events in promoter regions and the presence of a gene conversion gradient most likely explain the observed decrease of GC-ending codons with gene length and gene position.</p
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