Abstract: Empirical force fields and density functional theory
(DFT) was used to study the binding energies and structures of
methylamine on the surface of activated carbons (ACs). This is a first
step in studying the adsorption of alkyl amines on the surface of
functionalized ACs. The force fields used were Dreiding (DFF),
Universal (UFF) and Compass (CFF) models. The generalized
gradient approximation with Perdew Wang 91 (PW91) functional
was used for DFT calculations. In addition to obtaining the aminecarboxylic
acid adsorption energies, the results were used to establish
reliability of the empirical models for these systems. CFF predicted a
binding energy of -9.227 (kcal/mol) which agreed with PW91 at -
13.17 (kcal/mol), compared to DFF 0 (kcal/mol) and UFF -0.72
(kcal/mol). However, the CFF binding energies for the amine to ester
and ketone disagreed with PW91 results. The structures obtained
from all models agreed with PW91 results.
Abstract: The present work deals with the calculation of
transport properties of Hg0.8Cd0.2Te (MCT) semiconductor in
degenerate case. Due to their energy-band structure, this material
becomes degenerate at moderate doping densities, which are around
1015 cm-3, so that the usual Maxwell-Boltzmann approximation is
inaccurate in the determination of transport parameters. This problem
is faced by using Fermi-Dirac (F-D) statistics, and the non-parabolic
behavior of the bands may be approximated by the Kane model. The
Monte Carlo (MC) simulation is used here to determinate transport
parameters: drift velocity, mean energy and drift mobility versus
electric field and the doped densities. The obtained results are in
good agreement with those extracted from literature.
Abstract: The deterministic quantum transfer-matrix (QTM)
technique and its mathematical background are presented. This
important tool in computational physics can be applied to a class of
the real physical low-dimensional magnetic systems described by the
Heisenberg hamiltonian which includes the macroscopic molecularbased
spin chains, small size magnetic clusters embedded in some
supramolecules and other interesting compounds. Using QTM, the
spin degrees of freedom are accurately taken into account, yielding
the thermodynamical functions at finite temperatures.
In order to test the application for the susceptibility calculations to
run in the parallel environment, the speed-up and efficiency of
parallelization are analyzed on our platform SGI Origin 3800 with
p = 128 processor units. Using Message Parallel Interface (MPI)
system libraries we find the efficiency of the code of 94% for
p = 128 that makes our application highly scalable.
Abstract: Self-sensing estimates the air gap within an electro
magnetic path by analyzing the bearing coil current and/or voltage
waveform. The self-sensing concept presented in this paper has been
developed within the research project “Active Magnetic Bearings
with Supreme Reliability" and is used for position sensor fault
detection.
Within this new concept gap calculation is carried out by an alldigital
analysis of the digitized coil current and voltage waveform.
For analysis those time periods within the PWM period are used,
which give the best results. Additionally, the concept allows the
digital compensation of nonlinearities, for example magnetic
saturation, without degrading signal quality. This increases the
accuracy and robustness of the air gap estimation and additionally
reduces phase delays.
Beneath an overview about the developed concept first
measurement results are presented which show the potential of this
all-digital self-sensing concept.
Abstract: The paper presents the applications of artificial
intelligence technique called adaptive tabu search to design the
controller of a buck converter. The averaging model derived from the
DQ and generalized state-space averaging methods is applied to
simulate the system during a searching process. The simulations
using such averaging model require the faster computational time
compared with that of the full topology model from the software
packages. The reported model is suitable for the work in the paper in
which the repeating calculation is needed for searching the best
solution. The results will show that the proposed design technique
can provide the better output waveforms compared with those
designed from the classical method.
Abstract: A finite element analysis was conducted to determine
the effect of moisture diffusion and hygroscopic swelling in rice. A
parallel simple stochastic modeling was performed to predict the
number of grains cracked as a result of moisture absorption and
hygroscopic swelling. Rice grains were soaked in thermally (25 oC)
controlled water and then tested for compressive stress. The
destructive compressive stress tests revealed through compressive
stress calculation that the peak force required to cause cracking in
grains soaked in water reduced with time as soaking duration was
extended. Results of the experiment showed that several grains had
their value of the predicted compressive stress below the von Mises
stress and were interpreted as grains which become cracked and/or
broke during soaking. The technique developed in this experiment
will facilitate the approximation of the number of grains which will
crack during soaking.
Abstract: A new decomposition form is introduced in this report
to establish a criterion for the bi-partite separability of Bell diagonal
states. A such criterion takes a quadratic inequality of the coefficients
of a given Bell diagonal states and can be derived via a simple
algorithmic calculation of its invariants. In addition, the criterion can
be extended to a quantum system of higher dimension.
Abstract: Hydraulic conductivity is one parameter important for predicting the movement of water and contaminants dissolved in the water through the soil. The hydraulic conductivity is measured on soil samples in the lab and sometimes tests carried out in the field. The hydraulic conductivity has been related to soil particle diameter by a number of investigators. In this study, 25 set of soil samples with sand texture. The results show approximately success in predicting hydraulic conductivity from particle diameters data. The following relationship obtained from multiple linear regressions on data (R2 = 0.52): Where d10, d50 and d60, are the soil particle diameter (mm) that 10%, 50% and 60% of all soil particles are finer (smaller) by weight and Ks, saturated hydraulic conductivity is expressed in m/day. The results of regression analysis showed that d10 play a more significant role with respect to Ks, saturated hydraulic conductivity (m/day), and has been named as the effective parameter in Ks calculation.
Abstract: A computational study at the level density functional theory (DFT) was carried out to investigate the influences of Si and C-doping on the 14N and 27Al quadrupole coupling constant in the (10, 0) zigzag single ? walled Aluminum-Nitride nanotube (AlNNT). To this aim, a 1.16nm, length of AlNNT consisting of 40 Al atoms and 40 N atoms were selected where the end atoms are capped by hydrogen atom. To follow the purpose, three Si atoms and three C atoms were doped instead of three Al atoms and three N atoms as a central ring in the surface of the Si and C-doped AlNNT. At first both of systems optimized at the level of BLYP method and 6-31G (d) basis set and after that, the NQR parameters were calculated at the level BLYP method and 6-311+G** basis set in two optimized forms. The calculate CQ values for both optimized AlNNT systems, raw and Si and C-doped, reveal different electronic environments in the mentioned systems. It was also demonstrated that the end nuclei have the largest CQ values in both considered AlNNT systems. All the calculations were carried out using Gaussian 98 package of program.
Abstract: This article is focused on the calculation of heat
radiation intensity and its optimization on an aluminum mould
surface. The inside of the mould is sprinkled with a special powder
and its outside is heated by infra heaters located above the mould
surface, up to a temperature of 250°C. By this way artificial leathers
in the car industry are produced (e. g. the artificial leather on a car
dashboard). A mathematical model of heat radiation of infra heaters
on a mould surface is described in this paper. This model allows us to
calculate a heat-intensity radiation on the mould surface for the
concrete location of infra heaters above the mould surface. It is
necessary to ensure approximately the same heat intensity radiation
on the mould surface by finding a suitable location for the infra
heaters, and in this way the same material structure and color of
artificial leather. In the model we have used a genetic algorithm to
optimize the radiation intensity on the mould surface. Experimental
measured values for the heat radiation intensity by a sensor in the
surroundings of an infra heater are used for the calculation
procedures. A computational procedure was programmed in language
Matlab.
Abstract: Saccharomyces cerevisiae (baker-s yeast) can exhibit
sustained oscillations during the operation in a continuous bioreactor
that adversely affects its stability and productivity. Because of
heterogeneous nature of cell populations, the cell population balance
models can be used to capture the dynamic behavior of such cultures.
In this paper an unstructured, segregated model is used which is
based on population balance equation(PBE) and then in order to
simulation, the 4th order Rung-Kutta is used for time dimension and
three methods, finite difference, orthogonal collocation on finite
elements and Galerkin finite element are used for discretization of the
cell mass domain. The results indicate that the orthogonal collocation
on finite element not only is able to predict the oscillating behavior of
the cell culture but also needs much little time for calculations.
Therefore this method is preferred in comparison with other methods.
In the next step two controllers, a globally linearizing control (GLC)
and a conventional proportional-integral (PI) controller are designed
for controlling the total cell mass per unit volume, and performances
of these controllers are compared through simulation. The results
show that although the PI controller has simpler structure, the GLC
has better performance.
Abstract: A power cable is widely used for power supply in
power distributing networks and power transmission lines. Due to
limitations in the production, delivery and setting up power cables,
they are produced and delivered in several separate lengths. Cable
itself, consists of two cable terminations and arbitrary number of
cable joints, depending on the cable route length. Electrical stress
control is needed to prevent a dielectric breakdown at the end of the
insulation shield in both the air and cable insulation. Reliability of
cable joint depends on its materials, design, installation and operating
environment. The paper describes design and performance results for
new modeled cable joints. Design concepts, based on numerical
calculations, must be correct. An Equivalent Electrodes
Method/Boundary Elements Method-hybrid approach that allows
electromagnetic field calculations in multilayer dielectric media,
including inhomogeneous regions, is presented.
Abstract: A two-dimensional numerical simulation of the contribution
of both inertial and aerodynamic forces on the blade loads of
a Vertical-Axis Wind Turbine (VAWT) is presented. After describing
the computational model and the relative validation procedure, a
complete campaign of simulations - based on full RANS unsteady
calculations - is proposed for a three-bladed rotor architecture characterized
by a NACA 0021 airfoil. For each analyzed angular velocity,
the combined effect of pressure and viscous forces acting on every
rotor blade are compared to the corresponding centrifugal forces,
due to the revolution of the turbine, thus achieving a preliminary
estimation of the correlation between overall rotor efficiency and
structural blade loads.
Abstract: An electronic portal image device (EPID) has become
a method of patient-specific IMRT dose verification for radiotherapy.
Research studies have focused on pre and post-treatment verification,
however, there are currently no interventional procedures using EPID
dosimetry that measure the dose in real time as a mechanism to
ensure that overdoses do not occur and underdoses are detected as
soon as is practically possible. As a result, an EPID-based real time
dose verification system for dynamic IMRT was developed and was
implemented with MATLAB/Simulink. The EPID image acquisition
was set to continuous acquisition mode at 1.4 images per second. The
system defined the time constraint gap, or execution gap at the image
acquisition time, so that every calculation must be completed before
the next image capture is completed. In addition, the
Abstract: In this paper, we propose a novel concept of relative
distance measurement using Stereo Vision Technology and discuss
its implementation on a FPGA based real-time image processor. We
capture two images using two CCD cameras and compare them.
Disparity is calculated for each pixel using a real time dense disparity
calculation algorithm. This algorithm is based on the concept of
indexed histogram for matching. Disparity being inversely
proportional to distance (Proved Later), we can thus get the relative
distances of objects in front of the camera. The output is displayed on
a TV screen in the form of a depth image (optionally using pseudo
colors). This system works in real time on a full PAL frame rate (720
x 576 active pixels @ 25 fps).
Abstract: Added stresses due to adjacent structure should be
considered in foundation design and stress control in soil under the structure. This case is considered less than other cases in design and
calculation whereas stresses in implementation are greater than analytical stress.
Structure load are transmitted to earth by foundation and role of foundation is propagation of load on the continuous and half extreme
soil. This act cause that, present stresses lessen to allowable strength
of soil. Some researchers such as Boussinesq and westergaurd by
using of some assumption studied on this issue, theorically. Target of
this paper is study and evaluation of added stresses under structure
due to adjacent structure. For this purpose, by using of assumption, theoric relation and numeral methods, effects of adjacent structure
with 4 to 10 storeys on the main structure with 4 storeys are studied
and effect of parameters and sensitivity of them are evaluated.
Abstract: This article presents the results using a parametric approach and a Wavelet Transform in analysing signals emitting from the sperm whale. The extraction of intrinsic characteristics of these unique signals emitted by marine mammals is still at present a difficult exercise for various reasons: firstly, it concerns non-stationary signals, and secondly, these signals are obstructed by interfering background noise. In this article, we compare the advantages and disadvantages of both methods: Auto Regressive models and Wavelet Transform. These approaches serve as an alternative to the commonly used estimators which are based on the Fourier Transform for which the hypotheses necessary for its application are in certain cases, not sufficiently proven. These modern approaches provide effective results particularly for the periodic tracking of the signal's characteristics and notably when the signal-to-noise ratio negatively effects signal tracking. Our objectives are twofold. Our first goal is to identify the animal through its acoustic signature. This includes recognition of the marine mammal species and ultimately of the individual animal (within the species). The second is much more ambitious and directly involves the intervention of cetologists to study the sounds emitted by marine mammals in an effort to characterize their behaviour. We are working on an approach based on the recordings of marine mammal signals and the findings from this data result from the Wavelet Transform. This article will explore the reasons for using this approach. In addition, thanks to the use of new processors, these algorithms once heavy in calculation time can be integrated in a real-time system.
Abstract: This paper reports on investigations into capacity of a
Multiple Input Multiple Output (MIMO) wireless communication
system employing a uniform linear array (ULA) at the transmitter and
either a uniform linear array (ULA) or a uniform circular array (UCA)
antenna at the receiver. The transmitter is assumed to be surrounded by
scattering objects while the receiver is postulated to be free from
scattering objects. The Laplacian distribution of angle of arrival
(AOA) of a signal reaching the receiver is postulated. Calculations of
the MIMO system capacity are performed for two cases without and
with the channel estimation errors. For estimating the MIMO channel,
the scaled least square (SLS) and minimum mean square error
(MMSE) methods are considered.
Abstract: Traditional object segmentation methods are time consuming and computationally difficult. In this paper, onedimensional object detection along the secant lines is applied. Statistical features of texture images are computed for the recognition process. Example matrices of these features and formulae for calculation of similarities between two feature patterns are expressed. And experiments are also carried out using these features.
Abstract: As the electrical power industry is restructured, the electrical power exchange is becoming extended. One of the key information used to determine how much power can be transferred through the network is known as available transfer capability (ATC). To calculate ATC, traditional deterministic approach is based on the severest case, but the approach has the complexity of procedure. Therefore, novel approach for ATC calculation is proposed using cost-optimization method in this paper, and is compared with well-being method and risk-benefit method. This paper proposes the optimal transfer capability of HVDC system between mainland and a separated island in Korea through these three methods. These methods will consider production cost, wheeling charge through HVDC system and outage cost with one depth (N-1 contingency)