101 research outputs found
Проект парогазовой ТЭЦ с противодавленческими турбинами
Дипломный проект 86страниц, 5рисунков, 10таблиц, 10 источников, 1 приложение, 7 листов графического материала,
ТЕПЛОВАЯ СХЕМА, ПАРОГАЗОВАЯ УСТАНОВКА, КОТЕЛ-УТИЛИЗАТОР, ПАРОВАЯ ТУРБИНА СХЕМА КИП и А.
Объектом исследования является парогазовый энергоблок.
Цель работы – проект парогазового энергоблока.
В процессе работы выполнен расчет тепловой схемы расчетный для проектирования отопления режим.
режим, проектирование котла-утилизатора, технико-экономические расчеты.
В результате выполнения работы показаны преимущества парогазового
энергоблока на базе высокотемпературной газотурбинной установки SGT-800, проект позволяет повысить КПД энергоблока в сравнении с традиционными паросиловыми установками.
Технико-экономические расчеты показали быструю окупаемость проекта и низкую себестоимость электроэнергии.
Пояснительная записка выполнена в текстовом редакторе Microsoft Of-
fice Word 2007, чертежи в графических редакторах Компас.Graduation project 86stranits, 5risunkov, 10tablits 10 sources 1 annex, 7 sheets of graphic material,
Thermal circuit, combined cycle gas turbine, heat recovery boiler, steam turbine and instrumentation A. SCHEME
The object of the research is combined-cycle unit.
Objective - combined cycle power project.
In the process, calculated the thermal circuit current mode for heating design.
mode, design recovery boiler, technical and economic calculations.
As a result of the work shows the benefits of combined cycle gas turbine
power on the basis of high-temperature gas turbine SGT-800 installation, the project improves the power efficiency compared to conventional steam power plants.
Technical and economic calculations have shown a rapid return on the project and the low cost of electricity.
The explanatory note is made in the text editor Microsoft Of-
fice Word 2007 drawing in the graphic editors Compass
Chiral Asymmetry and the Spectral Action
We consider orthogonal connections with arbitrary torsion on compact
Riemannian manifolds. For the induced Dirac operators, twisted Dirac operators
and Dirac operators of Chamseddine-Connes type we compute the spectral action.
In addition to the Einstein-Hilbert action and the bosonic part of the Standard
Model Lagrangian we find the Holst term from Loop Quantum Gravity, a coupling
of the Holst term to the scalar curvature and a prediction for the value of the
Barbero-Immirzi parameter
Eta invariants for flat manifolds
Using H. Donnelly result from the article "Eta Invariants for G-Spaces" we
calculate the eta invariants of the signature operator for almost all
7-dimensional flat manifolds with cyclic holonomy group. In all cases this eta
invariants are an integer numbers. The article was motivated by D. D. Long and
A. Reid article "On the geometric boundaries of hyperbolic 4-manifolds, Geom.
Topology 4, 2000, 171-178Comment: 18 pages, a new version with referees comment
Beyond Einstein-Cartan gravity: Quadratic torsion and curvature invariants with even and odd parity including all boundary terms
Recently, gravitational gauge theories with torsion have been discussed by an
increasing number of authors from a classical as well as from a quantum field
theoretical point of view. The Einstein-Cartan(-Sciama-Kibble) Lagrangian has
been enriched by the parity odd pseudoscalar curvature (Hojman, Mukku, and
Sayed) and by torsion square and curvature square pieces, likewise of even and
odd parity. (i) We show that the inverse of the so-called Barbero-Immirzi
parameter multiplying the pseudoscalar curvature, because of the topological
Nieh-Yan form, can only be appropriately discussed if torsion square pieces are
included. (ii) The quadratic gauge Lagrangian with both parities, proposed by
Obukhov et al. and Baekler et al., emerges also in the framework of Diakonov et
al.(2011). We establish the exact relations between both approaches by applying
the topological Euler and Pontryagin forms in a Riemann-Cartan space expressed
for the first time in terms of irreducible pieces of the curvature tensor.
(iii) Only in a Riemann-Cartan spacetime, that is, in a spacetime with torsion,
parity violating terms can be brought into the gravitational Lagrangian in a
straightforward and natural way. Accordingly, Riemann-Cartan spacetime is a
natural habitat for chiral fermionic matter fields.Comment: 12 page latex, as version 2 an old file was submitted by mistake,
this is now the real corrected fil
A spinorial energy functional: critical points and gradient flow
On the universal bundle of unit spinors we study a natural energy functional
whose critical points, if dim M \geq 3, are precisely the pairs (g, {\phi})
consisting of a Ricci-flat Riemannian metric g together with a parallel
g-spinor {\phi}. We investigate the basic properties of this functional and
study its negative gradient flow, the so-called spinor flow. In particular, we
prove short-time existence and uniqueness for this flow.Comment: Small changes, final versio
The Holst Action by the Spectral Action Principle
We investigate the Holst action for closed Riemannian 4-manifolds with
orthogonal connections. For connections whose torsion has zero Cartan type
component we show that the Holst action can be recovered from the heat
asymptotics for the natural Dirac operator acting on left-handed spinor fields.Comment: We correct a sign mistake in Proposition 2.3. As a consequence the
main result (Theorem 3.4) becomes more natura
Manifolds with small Dirac eigenvalues are nilmanifolds
Consider the class of n-dimensional Riemannian spin manifolds with bounded
sectional curvatures and diameter, and almost non-negative scalar curvature.
Let r=1 if n=2,3 and r=2^{[n/2]-1}+1 if n\geq 4. We show that if the square of
the Dirac operator on such a manifold has small eigenvalues, then the
manifold is diffeomorphic to a nilmanifold and has trivial spin structure.
Equivalently, if M is not a nilmanifold or if M is a nilmanifold with a
non-trivial spin structure, then there exists a uniform lower bound on the r-th
eigenvalue of the square of the Dirac operator. If a manifold with almost
nonnegative scalar curvature has one small Dirac eigenvalue, and if the volume
is not too small, then we show that the metric is close to a Ricci-flat metric
on M with a parallel spinor. In dimension 4 this implies that M is either a
torus or a K3-surface
The spectral action and cosmic topology
The spectral action functional, considered as a model of gravity coupled to
matter, provides, in its non-perturbative form, a slow-roll potential for
inflation, whose form and corresponding slow-roll parameters can be sensitive
to the underlying cosmic topology. We explicitly compute the non-perturbative
spectral action for some of the main candidates for cosmic topologies, namely
the quaternionic space, the Poincare' dodecahedral space, and the flat tori. We
compute the corresponding slow-roll parameters and see we check that the
resulting inflation model behaves in the same way as for a simply-connected
spherical topology in the case of the quaternionic space and the Poincare'
homology sphere, while it behaves differently in the case of the flat tori. We
add an appendix with a discussion of the case of lens spaces.Comment: 55 pages, LaTe
Diverse tick-borne microorganisms identified in free-living ungulates in Slovakia
Background: Free-living ungulates are hosts of ixodid ticks and reservoirs of tick-borne microorganisms in central Europe and many regions around the world. Tissue samples and engorged ticks were obtained from roe deer, red deer, fallow deer, mouflon, and wild boar hunted in deciduous forests of south-western Slovakia. DNA isolated from these samples was screened for the presence of tick-borne microorganisms by PCR-based methods. Results: Ticks were found to infest all examined ungulate species. The principal infesting tick was Ixodes ricinus, identified on 90.4% of wildlife, and included all developmental stages. Larvae and nymphs of Haemaphysalis concinna were feeding on 9.6% of wildlife. Two specimens of Dermacentor reticulatus were also identified. Ungulates were positive for A. phagocytophilum and Theileria spp. Anaplasma phagocytophilum was found to infect 96.1% of cervids, 88.9% of mouflon, and 28.2% of wild boar, whereas Theileria spp. was detected only in cervids (94.6%). Importantly, a high rate of cervids (89%) showed mixed infections with both these microorganisms. In addition to A. phagocytophilum and Theileria spp., Rickettsia helvetica, R. monacensis, unidentified Rickettsia sp., Coxiella burnetii, "Candidatus Neoehrlichia mikurensis", Borrelia burgdorferi (s.l.) and Babesia venatorum were identified in engorged I. ricinus. Furthermore, A. phagocytophilum, Babesia spp. and Theileria spp. were detected in engorged H. concinna. Analysis of 16S rRNA and groEL gene sequences revealed the presence of five and two A. phagocytophilum variants, respectively, among which sequences identified in wild boar showed identity to the sequence of the causative agent of human granulocytic anaplasmosis (HGA). Phylogenetic analysis of Theileria 18S rRNA gene sequences amplified from cervids and engorged I. ricinus ticks segregated jointly with sequences of T. capreoli isolates into a moderately supported monophyletic clade. Conclusions: The findings indicate that free-living ungulates are reservoirs for A. phagocytophilum and Theileria spp. and engorged ixodid ticks attached to ungulates are good sentinels for the presence of agents of public and veterinary concern. Further analyses of the A. phagocytophilum genetic variants and Theileria species and their associations with vector ticks and free-living ungulates are required.Fil: Kazimírová, Mária. Slovak Academy of Sciences. Institute of Zoology; EslovaquiaFil: Hamšíková, Zuzana. Slovak Academy of Sciences. Institute of Zoology; EslovaquiaFil: Spitalská, Eva. Slovak Academy of Sciences. Institute of Virology. Biomedical Research Center,; EslovaquiaFil: Minichová, Lenka. Slovak Academy of Sciences. Institute of Virology. Biomedical Research Center,; EslovaquiaFil: Mahríková, Lenka. Slovak Academy of Sciences. Institute of Zoology; EslovaquiaFil: Caban, Radoslav. Široká ; EslovaquiaFil: Sprong, Hein. National Institute for Public Health and Environment.Laboratory for Zoonoses and Environmental Microbiology; Países BajosFil: Fonville, Manoj. National Institute for Public Health and Environment.Laboratory for Zoonoses and Environmental Microbiology; Países BajosFil: Schnittger, Leonhard. Instituto Nacional de Tecnología Agropecuaria. Centro de Investigación en Ciencias Veterinarias y Agronómicas. Instituto de Patobiología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Kocianová, Elena. Slovak Academy of Sciences. Institute of Virology. Biomedical Research Center,; Eslovaqui
Estimating Ixodes ricinus densities on the landscape scale
Background: The study describes the estimation of the spatial distribution of questing nymphal tick densities by investigating Ixodes ricinus in Southwest Germany as an example. The production of high-resolution maps of questing tick densities is an important key to quantify the risk of tick-borne diseases. Previous I. ricinus maps were based on quantitative as well as semi-quantitative categorisations of the tick density observed at study sites with different vegetation types or indices, all compiled on local scales. Here, a quantitative approach on the landscape scale is introduced.
Methods: During 2 years, 2013 and 2014, host-seeking ticks were collected each month at 25 sampling sites by flagging an area of 100 square meters. All tick stages were identified to species level to select nymphal ticks of I. ricinus, which were used to develop and calibrate Poisson regression models. The environmental variables height above sea level, temperature, relative humidity, saturation deficit and land cover classification were used as explanatory variables.
Results: The number of flagged nymphal tick densities range from zero (mountain site) to more than 1,000 nymphs/100 m. Calibrating the Poisson regression models with these nymphal densities results in an explained variance of 72 % and a prediction error of 110 nymphs/100 m in 2013. Generally, nymphal densities (maximum 374 nymphs/100 m), explained variance (46 %) and prediction error (61 nymphs/100 m2) were lower in 2014. The models were used to compile high-resolution maps with 0.5 km grid size for the study region of the German federal state Baden-Württemberg. The accuracy of the mapped tick densities was investigated by leave-one-out cross-validation resulting in root-mean-square-errors of 227 nymphs/100 m for 2013 and 104 nymphs/100 m for 2014.
Conclusions: The methodology introduced here may be applied to further tick species or extended to other study regions. Finally, the study is a first step towards the spatial estimation of tick-borne diseases in Central Europe
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