635 research outputs found
Design of wave energy converter system with linear generator
International Conference on Computational and Experimental Science and Engineering (ICCESEN) -- OCT 25-29, 2014 -- Antalya, TURKEYsahin, mustafa ergin/0000-0002-5121-6173WOS: 000363011700070It is not wrong to say that wave energy will be one of the most important energy sources to be used in the future, when it is thought that three-quarters of the world is covered by water. the initial investment and maintenance costs are the only expenses, beside not any price have to be paid for the primary energy. the wave energy does not leave any contaminants, as well as it is cheap, clean, environmentally, friendly and a great energy sources. in this study, wave energy converter system which has a four poles linear generator is discussed. the Linear generator model has been designed and created as a portable model. the results obtained from this model were examined
Assessing and managing scenery of the Caribbean Coast of Colombia
This study provides the coastal scenery assessment of 135 sites along the Colombian Caribbean littoral by
analysing 26 physical and human factors. Sites were categorised into five classes from Class 1, top grade
scenery, to Class 5, poor scenery. Fifty five percent of the investigated coastal areas were included in
Classes 1 and 2, 18% belonged to Class 3 and 47% of the sites fall into Classes 4 and 5. Classification of
analysed sites depends on the geological setting and the degree of human occupation. Classes 1 and 2
sites are located in natural protected areas in La Guajira and Magdalena departments. Low classification
recorded at Classes 3, 4 and 5 corresponds to a progressive decrease of both natural and (especially)
human parameters. Concerning coastal management issues, emphasis should be given to the upgrading
of human parameters eliminating litter and sewage evidences, vegetation debris and enhancing beach
nourishment work
Congenital Lymphoedema, Bronchiectasis And Seizure: Case Report
A l0-year-old girl with facial anomalies, mental retardation, peripheral lymphoedema, convulsions, cerebral cortical dysgenetic changes, bronchiectasis and chronic sinusitis is presented. She had features of both yellow nail syndrome and Hennekam syndrome. We think that our case might be a new congenital lymphoedema syndrome or an
intermediate form between these syndromes. East African Medical Journal Vol. 85 (3) 2008: pp. 145-14
One Loop Beta Functions in Topologically Massive Gravity
We calculate the running of the three coupling constants in cosmological,
topologically massive 3d gravity. We find that \nu, the dimensionless
coefficient of the Chern-Simons term, has vanishing beta function. The flow of
the cosmological constant and Newton's constant depends on \nu, and for any
positive \nu there exist both a trivial and a nontrivial fixed point.Comment: 44 pages, 16 figure
Structure and propertties of ball milled utrahigh-molecular weight Polyethylene - clay composite
In this work the composite material based on polymer matrix filled with clay is studied. The preparation of powder composition consists of mechanical activation of substances and further common ball milling of polymer and clay in a high energy planetary ball mill. The process is divided into two stages; the first stage involves crushing of clay to obtain a nanosized powder, and in the second stage preparation of powdered nanocomposite is carried out. New clay-polymer composite shows considerable increase in modulus of elasticity and a decrease in coefficient of friction
Ultrafast time-resolved spectroscopy of 1D metal-dielectric photonic crystals
We study the all-optical switching behavior of one-dimensional
metal-dielectric photonic crystals due to the nonlinearity of the free metal
electrons. A polychromatic pump-probe setup is used to determine the wavelength
and pump intensity dependence of the ultrafast transmission suppression as well
as the dynamics of the process on a subpicosecond timescale. We find ultrafast
(sub-picosecond) as well as a slow (millisecond) behavior. We present a model
of the ultrafast dynamics and nonlinear response which can fit the measured
data well and allows us to separate the thermal and the electronic response of
the system.Comment: 7 pages, 5 figure
Witten-Nester Energy in Topologically Massive Gravity
We formulate topologically massive supergravity with cosmological constant in
the first order formalism, and construct the Noether supercurrent and
superpotential associated with its local supersymmetry. Using these results, we
construct in ordinary topologically massive gravity the Witten-Nester integral
for conserved charges containing spinors which satisfy a generalized version of
Witten equation on the initial value surface. We show that the Witten-Nester
charge, represented as an integral over the boundary of the initial value
surface produces the Abbott-Deser-Tekin energy for asymptotically anti de
Sitter spacetimes. We consider all values of the Chern-Simons coupling
constant, including the critical value known as the chiral point, and study the
cases of standard Brown-Henneaux boundary conditions, as well as their weaker
version that allow a slower fall-off. Studying the Witten-Nester energy as a
bulk integral over the initial value surface instead, we find a bound on the
energy, and through it the sufficient condition for the positivity of the
energy. In particular, we find that spacetimes of Petrov type N that admit
globally well defined solutions of the generalized Witten equation have
positive energy.Comment: 43 page
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