Abstract: The current statuses of lifetime test of LaB6 hollow
cathode at the Lanzhou Institute of Physics (LIP), China, was
described. 5A LaB6 hollow cathode was design for LIPS-200 40mN
Xenon ion thruster, and it could be used for LHT-100 80 mN Hall
thruster, too. Life test of the discharge and neutralizer modes of LHC-5
hollow cathode were stared in October 2011, and cumulative operation
time reached 17,300 and 16,100 hours in April 2015, respectively. The
life of cathode was designed more than 11,000 hours. Parameters of
discharge and key structure dimensions were monitored in different
stage of life test indicated that cathodes were health enough. The test
will continue until the cathode cannot work or operation parameter is
not in normally. The result of the endurance test of cathode
demonstrated that the LaB6 hollow cathode is satisfied for the required
of thruster in life and performance.
Abstract: The analytical bright two soliton solution of the 3-
coupled nonlinear Schrödinger equations with variable coefficients in
birefringent optical fiber is obtained by Darboux transformation
method. To the design of ultra-speed optical devices, Soliton
interaction and control in birefringence fiber is investigated. Lax pair
is constructed for N coupled NLS system through AKNS method.
Using two-soliton solution, we demonstrate different interaction
behaviors of solitons in birefringent fiber depending on the choice of
control parameters. Our results shows that interactions of optical
solitons have some specific applications such as construction of logic
gates, optical computing, soliton switching, and soliton amplification
in wavelength division multiplexing (WDM) system.
Abstract: The customers use the best compromise criterion
between price and quality of service (QoS) to select or change
their Service Provider (SP). The SPs share the same market and
are competing to attract more customers to gain more profit. Due
to the divergence of SPs interests, we believe that this situation is a
non-cooperative game of price and QoS. The game converges to an
equilibrium position known Nash Equilibrium (NE). In this work, we
formulate a game theoretic framework for the dynamical behaviors
of SPs. We use Genetic Algorithms (GAs) to find the price and
QoS strategies that maximize the profit for each SP and illustrate
the corresponding strategy in NE. In order to quantify how this NE
point is performant, we perform a detailed analysis of the price of
anarchy induced by the NE solution. Finally, we provide an extensive
numerical study to point out the importance of considering price and
QoS as a joint decision parameter.
Abstract: A geoelectric survey was carried out in some parts of
Angwan Gwari, an outskirt of Lapai Local Government Area on
Niger State which belongs to the Nigerian Basement Complex, with
the aim of evaluating the soil corrosivity, aquifer transmissivity and
protective capacity of the area from which aquifer characterisation
was made. The G41 Resistivity Meter was employed to obtain fifteen
Schlumberger Vertical Electrical Sounding data along profiles in a
square grid network. The data were processed using interpex 1-D
sounding inversion software, which gives vertical electrical sounding
curves with layered model comprising of the apparent resistivities,
overburden thicknesses, and depth. This information was used to
evaluate longitudinal conductance and transmissivities of the layers.
The results show generally low resistivities across the survey area
and an average longitudinal conductance variation from
0.0237Siemens in VES 6 to 0.1261Siemens in VES 15 with almost
the entire area giving values less than 1.0 Siemens. The average
transmissivity values range from 96.45 Ω.m2 in VES 4 to 299070
Ω.m2 in VES 1. All but VES 4 and VES14 had an average
overburden greater than 400 Ω.m2, these results suggest that the
aquifers are highly permeable to fluid movement within, leading to
the possibility of enhanced migration and circulation of contaminants
in the groundwater system and that the area is generally corrosive.
Abstract: A Multi-dimensional computational fluid dynamics
(CFD) two-phase model was developed with the aim to simulate
the in-core coolant circuit of a pressurized heavy water reactor
(PHWR) of a commercial nuclear power plant (NPP). Due to the
fact that this PHWR is a Reactor Pressure Vessel type (RPV),
three-dimensional (3D) detailed modelling of the large reservoirs of
the RPV (the upper and lower plenums and the downcomer) were
coupled with an in-house finite volume one-dimensional (1D) code
in order to model the 451 coolant channels housing the nuclear fuel.
Regarding the 1D code, suitable empirical correlations for taking into
account the in-channel distributed (friction losses) and concentrated
(spacer grids, inlet and outlet throttles) pressure losses were used.
A local power distribution at each one of the coolant channels
was also taken into account. The heat transfer between the coolant
and the surrounding moderator was accurately calculated using a
two-dimensional theoretical model. The implementation of subcooled
boiling and condensation models in the 1D code along with the use
of functions for representing the thermal and dynamic properties of
the coolant and moderator (heavy water) allow to have estimations
of the in-core steam generation under nominal flow conditions for a
generic fission power distribution. The in-core mass flow distribution
results for steady state nominal conditions are in agreement with the
expected from design, thus getting a first assessment of the coupled
1/3D model. Results for nominal condition were compared with
those obtained with a previous 1/3D single-phase model getting more
realistic temperature patterns, also allowing visualize low values of
void fraction inside the upper plenum. It must be mentioned that the
current results were obtained by imposing prescribed fission power
functions from literature. Therefore, results are showed with the aim
of point out the potentiality of the developed model.
Abstract: Round addition differential fault analysis using
operation skipping for lightweight block ciphers with on-the-fly key
scheduling is presented. For 64-bit KLEIN, it is shown that only a pair
of correct and faulty ciphertexts can be used to derive the secret master
key. For PRESENT, one correct ciphertext and two faulty ciphertexts
are required to reconstruct the secret key. Furthermore, secret key
extraction is demonstrated for the LBlock Feistel-type lightweight
block cipher.
Abstract: Targeted drug delivery is a method of delivering
medication to a patient in a manner that increases the concentration
of the medication in some parts of the body relative to others.
Targeted drug delivery seeks to concentrate the medication in the
tissues of interest while reducing the relative concentration of the
medication in the remaining tissues. This improves efficacy of the
while reducing side effects. In the present work, we investigate the
effect of magnetic field, flow rate and particle concentration on the
capturing of magnetic particles transported in a stent implanted
fluidic channel. Iron oxide magnetic nanoparticles (Fe3O4)
nanoparticles were synthesized via co-precipitation method. The
synthesized Fe3O4 nanoparticles were added in the de-ionized (DI)
water to prepare the Fe3O4 magnetic particle suspended fluid. This
fluid is transported in a cylindrical tube of diameter 8 mm with help
of a peristaltic pump at different flow rate (25-40 ml/min). A
ferromagnetic coil of SS 430 has been implanted inside the
cylindrical tube to enhance the capturing of magnetic nanoparticles
under magnetic field. The capturing of magnetic nanoparticles was
observed at different magnetic magnetic field, flow rate and particle
concentration. It is observed that capture efficiency increases from
47-67% at magnetic field 2-5kG, respectively at particle
concentration 0.6mg/ml and at flow rate 30 ml/min. However, the
capture efficiency decreases from 65 to 44% by increasing the flow
rate from 25 to 40 ml/min, respectively. Furthermore, it is observed
that capture efficiency increases from 51 to 67% by increasing the
particle concentration from 0.3 to 0.6 mg/ml, respectively.
Abstract: The steady flow of a second order fluid through
constricted tube with slip velocity at wall is modeled and analyzed
theoretically. The governing equations are simplified by implying no
slip in radial direction. Based on Karman Pohlhausen procedure
polynomial solution for axial velocity profile is presented.
Expressions for pressure gradient, shear stress, separation and
reattachment points, and radial velocity are also calculated. The
effect of slip and no slip velocity on magnitude velocity, shear stress,
and pressure gradient are discussed and depicted graphically. It is
noted that when Reynolds number increases magnitude velocity of
the fluid decreases in both slip and no slip conditions. It is also found
that the wall shear stress, separation, and reattachment points are
strongly affected by Reynolds number.
Abstract: Annihilations, phase shifts, scattering lengths and
elastic cross sections of low energy positrons scattering from
magnesium atoms were studied using the least-squares variational
method (LSVM). The possibility of positron binding to the
magnesium atoms is investigated. A trial wave function is suggested
to represent e+-Mg elastic scattering and scattering parameters were
derived to estimate the binding energy and annihilation rates. The
trial function is taken to depend on several adjustable parameters, and
is improved iteratively by increasing the number of terms. The
present results have the same behavior as reported semi-empirical,
theoretical and experimental results. Especially, the estimated
positive scattering length supports the possibility of positronmagnesium
bound state system that was confirmed in previous
experimental and theoretical work.
Abstract: In this article, we used the residual correction method
to deal with transient thermoelastic problems with a hollow spherical
region when the continuum medium possesses spherically isotropic
thermoelastic properties. Based on linear thermoelastic theory, the
equations of hyperbolic heat conduction and thermoelastic motion
were combined to establish the thermoelastic dynamic model with
consideration of the deformation acceleration effect and non-Fourier
effect under the condition of transient thermal shock. The approximate
solutions of temperature and displacement distributions are obtained
using the residual correction method based on the maximum principle
in combination with the finite difference method, making it easier and
faster to obtain upper and lower approximations of exact solutions.
The proposed method is found to be an effective numerical method
with satisfactory accuracy. Moreover, the result shows that the effect
of transient thermal shock induced by deformation acceleration is
enhanced by non-Fourier heat conduction with increased peak stress.
The influence on the stress increases with the thermal relaxation time.
Abstract: Graphene, a single-atom sheet, has been considered as
the most promising material for making future nanoelectromechanical
systems as well as purely electrical switching with graphene
transistors. Graphene-based devices have advantages in scaled-up
device fabrication due to the recent progress in large area graphene
growth and lithographic patterning of graphene nanostructures. Here
we investigated its mechanical responses of circular graphene
nanoflake under the nanoindentation using classical molecular
dynamics simulations. A correlation between the load and the
indentation depth was constructed. The nanoindented force in this
work was applied to the center point of the circular graphene nanoflake
and then, the resonance frequency could be tuned by a nanoindented
depth. We found the hardening or the softening of the graphene
nanoflake during its nanoindented-deflections, and such properties
were recognized by the shift of the resonance frequency. The
calculated mechanical parameters in the force-vs-deflection plot were
in good agreement with previous experimental and theoretical works.
This proposed schematics can detect the pressure via the deflection
change or/and the resonance frequency shift, and also have great
potential for versatile applications in nanoelectromechanical systems.
Abstract: Exact solution of an unsteady MHD flow of elasticoviscous
fluid through a porous media in a tube of elliptic cross
section under the influence of magnetic field and constant pressure
gradient has been obtained in this paper. Initially, the flow is
generated by a constant pressure gradient. After attaining the steady
state, the pressure gradient is suddenly withdrawn and the resulting
fluid motion in a tube of elliptical cross section by taking into
account of the porosity factor and magnetic parameter of the
bounding surface is investigated. The problem is solved in two-stages
the first stage is a steady motion in tube under the influence of a
constant pressure gradient, the second stage concern with an unsteady
motion. The problem is solved employing separation of variables
technique. The results are expressed in terms of a non-dimensional
porosity parameter, magnetic parameter and elastico-viscosity
parameter, which depends on the Non-Newtonian coefficient. The
flow parameters are found to be identical with that of Newtonian case
as elastic-viscosity parameter, magnetic parameter tends to zero, and
porosity tends to infinity. The numerical results were simulated in
MATLAB software to analyze the effect of Elastico-viscous
parameter, porosity parameter, and magnetic parameter on velocity
profile. Boundary conditions were satisfied. It is seen that the effect
of elastico-viscosity parameter, porosity parameter and magnetic
parameter of the bounding surface has significant effect on the
velocity parameter.
Abstract: CuO thin films were deposited by spray ultrasonic
pyrolysis with different precursor solution. Two staring solution slats
were used namely: copper acetate and copper chloride. The influence
of these solutions on CuO thin films proprieties of is instigated. The
X rays diffraction (XDR) analysis indicated that the films deposed
with copper acetate are amorphous however the films elaborated with
copper chloride have monoclinic structure. UV- Visible transmission
spectra showed a strong absorbance of the deposited CuO thin films
in the visible region. Electrical characterization has shown that CuO
thin films prepared with copper acetate have a higher electrical
conductivity.
Abstract: The measurement of organ radiation exposure dose is
one of the most important steps to be taken initially, for developing a
new radiopharmaceutical. In this study, the dosimetric studies of a
novel agent for SPECT-imaging of the bone metastasis, 111In-
1,4,7,10-tetraazacyclododecane-1,4,7,10 tetraethylene phosphonic
acid (111In-DOTMP) complex, have been carried out to estimate the
dose in human organs based on the data derived from rats. The
radiolabeled complex was prepared with high radiochemical purity in
the optimal conditions. Biodistribution studies of the complex was
investigated in the male Syrian rats at selected times after injection
(2, 4, 24 and 48 h). The human absorbed dose estimation of the
complex was made based on data derived from the rats by the
radiation absorbed dose assessment resource (RADAR) method.
111In-DOTMP complex was prepared with high radiochemical purity
of >99% (ITLC). Total body effective absorbed dose for 111In-
DOTMP was 0.061 mSv/MBq. This value is comparable to the other
111In clinically used complexes. The results show that the dose with
respect to the critical organs is satisfactory within the acceptable
range for diagnostic nuclear medicine procedures. Generally, 111In-
DOTMP has interesting characteristics and can be considered as a
viable agent for SPECT-imaging of the bone metastasis in the near
future.
Abstract: In this paper, the results of Kano from one dimensional
cosine and sine series are extended to two dimensional cosine and sine
series. To extend these results, some classes of coefficient sequences
such as class of semi convexity and class R are extended from
one dimension to two dimensions. Further, the function f(x, y) is
two dimensional Fourier Cosine and Sine series or equivalently it
represents an integrable function or not, has been studied. Moreover,
some results are obtained which are generalization of Moricz’s
results.
Abstract: We consider the problem of stabilization of an unstable
heat equation in a 2-D, 3-D and generally n-D domain by deriving a
generalized backstepping boundary control design methodology. To
stabilize the systems, we design boundary backstepping controllers
inspired by the 1-D unstable heat equation stabilization procedure.
We assume that one side of the boundary is hinged and the other
side is controlled for each direction of the domain. Thus, controllers
act on two boundaries for 2-D domain, three boundaries for 3-D
domain and ”n” boundaries for n-D domain. The main idea of the
design is to derive ”n” controllers for each of the dimensions by
using ”n” kernel functions. Thus, we obtain ”n” controllers for the
”n” dimensional case. We use a transformation to change the system
into an exponentially stable ”n” dimensional heat equation. The
transformation used in this paper is a generalized Volterra/Fredholm
type with ”n” kernel functions for n-D domain instead of the one
kernel function of 1-D design.
Abstract: It is well-known that, using principal weak flatness
property, some important monoids are characterized, such as regular
monoids, left almost regular monoids, and so on. In this article, we
define a generalization of principal weak flatness called GP-Flatness,
and will characterize monoids by this property of their right (Rees
factor) acts. Also we investigate new classes of monoids called
generally regular monoids and generally left almost regular monoids.
Abstract: Analytical techniques for measuring and planning
railway capacity expansion activities have been considered in this
article. A preliminary mathematical framework involving track
duplication and section sub divisions is proposed for this task. In
railways, these features have a great effect on network performance
and for this reason they have been considered. Additional motivations
have also arisen from the limitations of prior models that have not
included them.
Abstract: In this study, we examine some spectral properties
of non-selfadjoint matrix-valued difference equations consisting of
a polynomial-type Jost solution. The aim of this study is to
investigate the eigenvalues and spectral singularities of the difference
operator L which is expressed by the above-mentioned difference
equation. Firstly, thanks to the representation of polynomial type Jost
solution of this equation, we obtain asymptotics and some analytical
properties. Then, using the uniqueness theorems of analytic functions,
we guarantee that the operator L has a finite number of eigenvalues
and spectral singularities.
Abstract: In this paper, a asymptotically periodic predator-prey
model with Modified Leslie-Gower and Holling-Type II schemes
is investigated. Some sufficient conditions for the uniformly strong
persistence of the system are established. Our result is an important
complementarity to the earlier results.