Abstract: Microstrip antennas are conformable to planar and
nonplanar surfaces, simple and inexpensive to fabricate using modern
printed-circuit technology. Circular polarization of low-profile
microstrip patch with high bandwidth is achieved in this research
through the use of a three-cross-arms branch-line coupler with
sequential rotated arrays, another low-profile antenna of hollow
cylinder is also proposed and the function of reconnaissance with
microstrip antenna on Mini UAV (unmanned aerial vehicle) are
evaluated in practical flight test.
Abstract: This work contains information about the influence low-level optical irradiation on sperm motility of sturgeon fish. On the basis of given and earlier received data the following conclusion has been made. Among the photophysical processes of a resonant and not resonant nature (oriented action of light; action of gradient forces; dipole-dipole interaction; termooptical processes), which are capable to cause the photobiological effects depended on such laserspecific characteristics as polarization and coherency, determining influence belongs to oriented action of light and dipole-dipole interactions among the processes studied in the present work.
Abstract: A tunable photonic microwave bandpass filter with
negative coefficient based on an electro-optic phase modulator (EOPM) and a variable polarization beamsplitter (VPBS) is
demonstrated. A two-tap microwave bandpass filter with one negative coefficient is presented. The chromatic dispersion and
optical coherence are not affected on this filter.
Abstract: A study of electromagnetic flow meter is presented in the paper. Comparison has been made between the analytical and the numerical results by the use of FEM numerical analysis (Quick Field 5.6) for determining polarization voltage through the circle cross section of the polarization transducer. Exciting and geometrical parameters increasing its effectiveness has been examined. The aim is to obtain maximal output signal. The investigations include different variants of the magnetic flux density distribution around the tube: homogeneous field of magnitude Bm, linear distribution with maximal value Bm and trapezium distribution conserving the same exciting magnetic energy as the homogeneous field.
Abstract: As a matter of the fact that online social networks like
Twitter, Facebook and MySpace have experienced an extensive
growth in recent years. Social media offers individuals with a tool for
communicating and interacting with one another. These social
networks enable people to stay in touch with other people and
express themselves. This process makes the users of online social
networks active creators of content rather than being only consumers
of traditional media. That’s why millions of people show strong
desire to learn the methods and tools of digital content production
and necessary communication skills. However, the booming interest
in communication and interaction through online social networks and
high level of eagerness to invent and implement the ways to
participate in content production raise some privacy and security
concerns.
This presentation aims to open the assumed revolutionary,
democratic and liberating nature of the online social media up for
discussion by reviewing some recent political developments in
Turkey. Firstly, the role of Internet and online social networks in
mobilizing collective movements through social interactions and
communications will be questioned. Secondly, some cases from Gezi
and Okmeydanı Protests and also December 17-25 period will be
presented in order to illustrate misinformation and manipulation in
social media and violation of individual privacy through online social
networks in order to damage social unity and stability contradictory
to democratic nature of online social networking.
Abstract: The finite-difference time-domain (FDTD) method is
one of the most widely used computational methods in
electromagnetic. This paper describes the design of two-dimensional
(2D) FDTD simulation software for transverse magnetic (TM)
polarization using Berenger's split-field perfectly matched layer
(PML) formulation. The software is developed using Matlab
programming language. Numerical examples validate the software.
Abstract: We report on a high-speed quantum cryptography
system that utilizes simultaneous entanglement in polarization and in
“time-bins". With multiple degrees of freedom contributing to the
secret key, we can achieve over ten bits of random entropy per detected coincidence. In addition, we collect from multiple spots o
the downconversion cone to further amplify the data rate, allowing usto achieve over 10 Mbits of secure key per second.
Abstract: Degradation of polymeric insulation systems of
electrical equipments increases the space charge density and the
concentration of electrical dipoles. By consequence, the maximum
values and the slopes of absorption/resorption (A/R) currents can
change with insulation systems ageing. In this paper, an analysis of
the nature of the A/R currents and the importance of their
components, especially the polarization current and the current given
by the space charge, is presented. The experimental study concerns
the A/R currents measurements of plane samples (made from
CALMICAGLAS tapes), virgin and thermally accelerated aged. The
obtained results show that the ageing process produces an increase of
the values and a decrease of shapes of the A/R currents. Finally, the
possibility of estimating insulations ageing state and lifetime from
A/R currents measurements is discussed.
Abstract: Polarization modulation infrared reflection absorption
spectroscopy (PM-IRRAS) in combination with electrochemistry,
was employed to study the influence of surface charge (potential) on
the kinetics of bovine serum albumin (BSA) adsorption on a
biomedical-grade 316LVM stainless steel surface is discussed. The
BSA adsorption kinetics was found to greatly depend on the surface
potential. With an increase in surface potential towards more
negative values, both the BSA initial adsorption rate and the
equilibrium (saturated) surface concentration also increased. Both
effects were explained on the basis of replacement of well-ordered
water molecules at the 316LVM / solution interface, i.e. by the
increase in entropy of the system.
Abstract: Martensitic stainless steels have been extensively used for their good corrosion resistance and better mechanical properties. Heat treatment was suggested as one of the most excellent ways to this regard; hence, it affects the microstructure, mechanical and corrosion properties of the steel. In the current research work the microstructural changes and corrosion behavior in an AISI 420A stainless steel exposed to temperatures in the 980-1035oC range were investigated. The heat treatment is carried out in vacuum furnace within the said temperature range. The quenching of the samples was carried out in oil, brine and water media. The formation and stability of passive film was studied by Open Circuit Potential, Potentiodynamic polarization and Electrochemical Scratch Tests. The Electrochemical Impedance Spectroscopy results simulated with Equivalent Electrical Circuit suggested bilayer structure of outer porous and inner barrier oxide films. The quantitative data showed thick inner barrier oxide film retarded electrochemical reactions. Micrographs of the quenched samples showed sigma and chromium carbide phases which prove the corrosion resistance of steel alloy.
Abstract: This paper unifies power optimization approaches in
various energy converters, such as: thermal, solar, chemical, and
electrochemical engines, in particular fuel cells. Thermodynamics
leads to converter-s efficiency and limiting power. Efficiency
equations serve to solve problems of upgrading and downgrading of
resources. While optimization of steady systems applies the
differential calculus and Lagrange multipliers, dynamic optimization
involves variational calculus and dynamic programming. In reacting
systems chemical affinity constitutes a prevailing component of an
overall efficiency, thus the power is analyzed in terms of an active
part of chemical affinity. The main novelty of the present paper in the
energy yield context consists in showing that the generalized heat
flux Q (involving the traditional heat flux q plus the product of
temperature and the sum products of partial entropies and fluxes of
species) plays in complex cases (solar, chemical and electrochemical)
the same role as the traditional heat q in pure heat engines.
The presented methodology is also applied to power limits in fuel
cells as to systems which are electrochemical flow engines propelled
by chemical reactions. The performance of fuel cells is determined by
magnitudes and directions of participating streams and mechanism of
electric current generation. Voltage lowering below the reversible
voltage is a proper measure of cells imperfection. The voltage losses,
called polarization, include the contributions of three main sources:
activation, ohmic and concentration. Examples show power maxima
in fuel cells and prove the relevance of the extension of the thermal
machine theory to chemical and electrochemical systems. The main
novelty of the present paper in the FC context consists in introducing
an effective or reduced Gibbs free energy change between products p
and reactants s which take into account the decrease of voltage and
power caused by the incomplete conversion of the overall reaction.
Abstract: Computational fluid dynamics (CFD) simulations
carried out in this paper show that spacer orientation has a major
influence on temperature patterns and on the heat transfer rates. The
local heat flux values significantly vary from high to very low values
at each filament when spacer touches the membrane surface. The
heat flux profile is more uniform when spacer filaments are not in
contact with the membrane thus making this arrangement more
beneficial. The temperature polarization is also found to be less in
this case when compared to the empty channel.
Abstract: This paper evaluate the multilevel modulation for
different techniques such as amplitude shift keying (M-ASK), MASK,
differential phase shift keying (M-ASK-Bipolar), Quaternary
Amplitude Shift Keying (QASK) and Quaternary Polarization-ASK
(QPol-ASK) at a total bit rate of 107 Gbps. The aim is to find a costeffective
very high speed transport solution. Numerical investigation
was performed using Monte Carlo simulations. The obtained results
indicate that some modulation formats can be operated at 100Gbps
in optical communication systems with low implementation effort
and high spectral efficiency.
Abstract: We theoretically demonstrate modulation of light
polarization by a crossed rectangular hole array with asymmetric arm
lengths. There are two waveguide modes that can modulate the x- and
y- polarized incident waves independently. A specific structure is
proposed to convert a left-hand incident wave to a right-hand outgoing
wave by transmission.
Abstract: The solvated electron is self-trapped (polaron) owing
to strong interaction with the quantum polarization field. If the
electron and quantum field are strongly coupled then the collective
localized state of the field and quasi-particle is formed. In such a
formation the electron motion is rather intricate. On the one hand the
electron oscillated within a rather deep polarization potential well
and undergoes the optical transitions, and on the other, it moves
together with the center of inertia of the system and participates in
the thermal random walk. The problem is to separate these motions
correctly, rigorously taking into account the conservation laws. This
can be conveniently done using Bogolyubov-Tyablikov method of
canonical transformation to the collective coordinates. This
transformation removes the translational degeneracy and allows one
to develop the successive approximation algorithm for the energy and
wave function while simultaneously fulfilling the law of conservation
of total momentum of the system. The resulting equations determine
the electron transitions and depend explicitly on the translational
velocity of the quasi-particle as whole. The frequency of optical
transition is calculated for the solvated electron in ammonia, and an
estimate is made for the thermal-induced spectral bandwidth.
Abstract: Recently, several designs of single fed circularly
polarized microstrip antennas have been studied. Relatively, a few
designs for achieving circular polarization using triangular microstrip
antenna are available. Typically existing design of single fed
circularly polarized triangular microstrip antennas include the use of
equilateral triangular patch with a slit or a horizontal slot on the patch
or addition a narrow band stub on the edge or a vertex of triangular
patch.
In other word, with using a narrow band tune stub on middle of an
edge of triangle causes of facility to compensate the possible
fabrication error and substrate materials with easier adjusting the
tuner stub length. Even though disadvantages of this method is very
long of stub (approximate 1/3 length of triangle edge). In this paper,
instead of narrow band stub, a wide band stub has been applied,
therefore the length of stub by this method has been decreased
around 1/10 edge of triangle in addition changing the aperture angle
of stub, provides more facility for designing and producing circular
polarization wave.
Abstract: We demonstrate single-photon interference over 10 km using a plug and play system for quantum key distribution. The quality of the interferometer is measured by using the interferometer
visibility. The coding of the signal is based on the phase coding and the value of visibility is based on the interference effect, which result a number of count. The setup gives full control of polarization inside
the interferometer. The quality measurement of the interferometer is based on number of count per second and the system produces 94 % visibility in one of the detectors.
Abstract: Analytically the effect of polarization dependent loss on a high speed fiber optic communication link has been investigated. PDL and the signal's incoming state of polarization (SOP) have a significant co-relation between them and their various combinations produces different effects on the system behavior which has been inspected. Pauli's spin operator and PDL parameters are combined together to observe the attenuation effect induced by PDL in a link containing multiple PDL elements. It is found that in the presence of PDL the Q-factor and BER at the receiver undergoes fluctuation causing the system to be unstable and results show that it is mainly due to optical-signal-to-parallel-noise ratio (OSNItpar) that these parameters fluctuate. Generally the Q-factor, BER deteriorates as the value of average PDL in the link increases except for depolarized light for which the system parameters improves when PDL increases.
Abstract: We have investigated the effect of piezoelectric (PZ)
polarization property in binary as well as in ternary wurtzite nitrides.
It is found that with the presence of PZ polarization property, the
phonon group velocity is modified. The change in phonon group
velocity due to PZ polarization effect directly depends on
piezoelectric tensor value. Using different piezoelectric tensor values
recommended by different workers in the literature, percent change in
group velocities of phonons has been estimated. The Debye
temperatures and frequencies of binary nitrides GaN, AlN and InN
are also calculated using the modified group velocities. For ternary
nitrides AlxGa(1-x)N, InxGa(1-x)N and InxAl(1-x)N, the phonon group
velocities have been calculated as a functions of composition. A
small positive bowing is observed in phonon group velocities of
ternary alloys. Percent variations in phonon group velocities are also
calculated for a straightforward comparison among ternary nitrides.
The results are expected to show a change in phonon relaxation rates
and thermal conductivity of III-nitrides when piezoelectric
polarization property is taken into consideration.