Abstract: Bendability is constrained by maximum top roller
load imparting capacity of the machine. Maximum load is
encountered during the edge pre-bending stage of roller bending.
Capacity of 3-roller plate bending machine is specified by
maximum thickness and minimum shell diameter combinations that
can be pre-bend for given plate material of maximum width.
Commercially available plate width or width of the plate that can be
accommodated on machine decides the maximum rolling width.
Original equipment manufacturers (OEM) provide the machine
capacity chart based on reference material considering perfectly
plastic material model. Reported work shows the bendability analysis
of heavy duty 3-roller plate bending machine. The input variables for
the industry are plate thickness, shell diameter and material property
parameters, as it is fixed by the design. Analytical models of
equivalent thickness, equivalent width and maximum width based on
power law material model were derived to study the bendability.
Equation of maximum width provides bendability for designed
configuration i.e. material property, shell diameter and thickness
combinations within the machine limitations. Equivalent thicknesses
based on perfectly plastic and power law material model were
compared for four different materials grades of C-Mn steel in order
to predict the bend-ability. Effect of top roller offset on the
bendability at maximum top roller load imparting capacity is
reported.
Abstract: Cs-type nanocomposite zeolite membrane was successfully synthesized on an alumina ceramic hollow fibre with a mean outer diameter of 1.7 mm; cesium cationic exchange test was carried out inside test module with mean wall thickness of 230 μm and an average crossing pore size smaller than 0.2 μm. Separation factor of n-butane/H2 obtained indicate that a relatively high quality closed to 20. Maxwell-Stefan modeling provides an equivalent thickness lower than 1 µm. To compare the difference an application to CO2/N2 separation has been achieved, reaching separation factors close to (4,18) before and after cation exchange on H-zeolite membrane formed within the pores of a ceramic alumina substrate.
Abstract: Kish Islands in South of Iran is located in coastal
water near Hormozgan Province. Based on the wind 3-hour statistics
in Kish station, the mean annual windspeed in this Island is 8.6 knot
(4.3 m/s). The maximum windspeed recorded in this stations 47 knot
(23.5 m/s). In 45.7 percent of recorded times, windspeed has been
Zero or less than 8 knot which is not suitable to use the wind energy.
But in 54.3 percent of recorded times, windspeed has been more than
8 knot and suitable to use wind energy to run turbines. In 40.2
percent of recorded times, windspeed has been between 8 to 16 knot,
in 13 percent of times between 16 to 24 knot and in 1 percent of
times it has been higher than 24 knot. In this station, the direction of
winds higher than 8 is west and wind direction in Kish station is
stable in most times of the year.With regard to high – speed and
stable direction winds during the year and also shallow coasts near
this is land, it is possible to build offshore wind farms near Kish
Island and utilize wind energy produce the electricity required in this
Island during most of the year.
Abstract: Several works regarding facial recognition have dealt with methods which identify isolated characteristics of the face or with templates which encompass several regions of it. In this paper a new technique which approaches the problem holistically dispensing with the need to identify geometrical characteristics or regions of the face is introduced. The characterization of a face is achieved by randomly sampling selected attributes of the pixels of its image. From this information we construct a set of data, which correspond to the values of low frequencies, gradient, entropy and another several characteristics of pixel of the image. Generating a set of “p" variables. The multivariate data set with different polynomials minimizing the data fitness error in the minimax sense (L∞ - Norm) is approximated. With the use of a Genetic Algorithm (GA) it is able to circumvent the problem of dimensionality inherent to higher degree polynomial approximations. The GA yields the degree and values of a set of coefficients of the polynomials approximating of the image of a face. By finding a family of characteristic polynomials from several variables (pixel characteristics) for each face (say Fi ) in the data base through a resampling process the system in use, is trained. A face (say F ) is recognized by finding its characteristic polynomials and using an AdaBoost Classifier from F -s polynomials to each of the Fi -s polynomials. The winner is the polynomial family closer to F -s corresponding to target face in data base.
Abstract: Coronary artery bypass grafts (CABG) are widely
studied with respect to hemodynamic conditions which play
important role in presence of a restenosis. However, papers which
concern with constitutive modeling of CABG are lacking in the
literature. The purpose of this study is to find a constitutive model for
CABG tissue. A sample of the CABG obtained within an autopsy
underwent an inflation–extension test. Displacements were
recoredered by CCD cameras and subsequently evaluated by digital
image correlation. Pressure – radius and axial force – elongation
data were used to fit material model. The tissue was modeled as onelayered
composite reinforced by two families of helical fibers. The
material is assumed to be locally orthotropic, nonlinear,
incompressible and hyperelastic. Material parameters are estimated
for two strain energy functions (SEF). The first is classical
exponential. The second SEF is logarithmic which allows
interpretation by means of limiting (finite) strain extensibility.
Presented material parameters are estimated by optimization based
on radial and axial equilibrium equation in a thick-walled tube. Both
material models fit experimental data successfully. The exponential
model fits significantly better relationship between axial force and
axial strain than logarithmic one.
Abstract: Modeling transfer phenomena in several chemical
engineering operations leads to the resolution of partial differential
equations systems. According to the complexity of the operations
mechanisms, the equations present a nonlinear form and analytical
solution became difficult, we have then to use numerical methods
which are based on approximations in order to transform a
differential system to an algebraic one.Finite element method is one
of numerical methods which can be used to obtain an accurate
solution in many complex cases of chemical engineering.The packed
columns find a large application like contactor for liquid-liquid
systems such solvent extraction. In the literature, the modeling of this
type of equipment received less attention in comparison with the
plate columns.A mathematical bidimensionnal model with radial and
axial dispersion, simulating packed tower extraction behavior was
developed and a partial differential equation was solved using the
finite element method by adopting the Galerkine model. We
developed a Mathcad program, which can be used for a similar
equations and concentration profiles are obtained along the column.
The influence of radial dispersion was prooved and it can-t be
neglected, the results were compared with experimental concentration
at the top of the column in the extraction system:
acetone/toluene/water.
Abstract: In the recent works related with mixture discriminant
analysis (MDA), expectation and maximization (EM) algorithm is
used to estimate parameters of Gaussian mixtures. But, initial values
of EM algorithm affect the final parameters- estimates. Also, when
EM algorithm is applied two times, for the same data set, it can be
give different results for the estimate of parameters and this affect the
classification accuracy of MDA. Forthcoming this problem, we use
Self Organizing Mixture Network (SOMN) algorithm to estimate
parameters of Gaussians mixtures in MDA that SOMN is more robust
when random the initial values of the parameters are used [5]. We
show effectiveness of this method on popular simulated waveform
datasets and real glass data set.
Abstract: A high energy dual-wavelength extracavity KTA
optical parametric oscillator (OPO) with excellent stability and beam
quality, which is pumped by a Q-switched single-longitudinal-mode
Nd:YAG laser, has been demonstrated based on a type II noncritical
phase matching (NCPM) KTA crystal. The maximum pulse energy of
10.2 mJ with the output stability of better than 4.1% rms at 3.467 μm is
obtained at the repetition rate of 10 Hz and pulse width of 2 ns, and the
11.9 mJ of 1.535 μm radiation is obtained simultaneously. This
extracavity NCPM KTA OPO is very useful when high energy, high
beam quality and smooth time domain are needed.
Abstract: Prior to the use of detectors, characteristics
comparison study was performed and baseline established. In patient
specific QA, the portal dosimetry mean values of area gamma,
average gamma and maximum gamma were 1.02, 0.31 and 1.31 with
standard deviation of 0.33, 0.03 and 0.14 for IMRT and the
corresponding values were 1.58, 0.48 and 1.73 with standard
deviation of 0.31, 0.06 and 0.66 for VMAT. With ImatriXX 2-D
array system, on an average 99.35% of the pixels passed the criteria
of 3%-3 mm gamma with standard deviation of 0.24 for dynamic
IMRT. For VMAT, the average value was 98.16% with a standard
deviation of 0.86. The results showed that both the systems can be
used in patient specific QA measurements for IMRT and VMAT.
The values obtained with the portal dosimetry system were found to
be relatively more consistent compared to those obtained with
ImatriXX 2-D array system.
Abstract: A closed-loop controlled wireless power transmission circuit block for implantable biomedical applications is described in this paper. The circuit consists of one front-end rectifier, power management sub-block including bandgap reference and low drop-out regulators (LDOs) as well as transmission power detection / feedback circuits. Simulation result shows that the front-end rectifier achieves 80% power efficiency with 750-mV single-end peak-to-peak input voltage and 1.28-V output voltage under load current of 4 mA. The power management block can supply 1.8mA average load current under 1V consuming only 12μW power, which is equivalent to 99.3% power efficiency. The wireless power transmission block described in this paper achieves a maximum power efficiency of 80%. The wireless power transmission circuit block is designed and implemented using UMC 65-nm CMOS/RF process. It occupies 1 mm × 1.2 mm silicon area.
Abstract: The aim of this work is to determine the supersonic
nozzle profiles used in propulsion, for the launchers or embarked
with the satellites. This design has as a role firstly, to give a
important propulsion, i.e. with uniform and parallel flow at exit,
secondly to find a short length profiles without modification of the
flow in the nozzle. The first elaborate program is used to determine
the profile of divergent by using the characteristics method for an
axisymmetric flow. The second program is conceived by using the
finite volume method to determine and test the profile found
connected to a convergent.
Abstract: This paper presents a model for the evaluation of
energy performance and aerodynamic forces acting on a small
straight-bladed Darrieus-type vertical axis wind turbine depending on
blade geometrical section. It consists of an analytical code coupled to
a solid modeling software, capable of generating the desired blade
geometry based on the desired blade design geometric parameters.
Such module is then linked to a finite volume commercial CFD code
for the calculation of rotor performance by integration of the
aerodynamic forces along the perimeter of each blade for a full period
of revolution.After describing and validating the computational
model with experimental data, the results of numerical simulations
are proposed on the bases of two candidate airfoil sections, that is a
classical symmetrical NACA 0021 blade profile and the recently
developed DU 06-W-200 non-symmetric and laminar blade
profile.Through a full CFD campaign of analysis, the effects of blade
geometrical section on angle of attack are first investigated and then
the overall rotor torque and power are analyzed as a function of blade
azimuthal position, achieving a numerical quantification of the
influence of airfoil geometry on overall rotor performance.
Abstract: This paper aims to develop a model that assists the
international retailer in selecting the country that maximizes the
degree of fit between the retailer-s goals and the country
characteristics in his initial internationalization move. A two-stage
multi criteria decision model is designed integrating the Analytic
Hierarchy Process (AHP) and Goal Programming. Ethical, cultural,
geographic and economic proximity are identified as the relevant
constructs of the internationalization decision. The constructs are
further structured into sub-factors within analytic hierarchy. The
model helps the retailer to integrate, rank and weigh a number of
hard and soft factors and prioritize the countries accordingly. The
model has been implemented on a Turkish luxury goods retailer who
was planning to internationalize. Actual entry of the specific retailer
in the selected country is a support for the model. Implementation on
a single retailer limits the generalizability of the results; however, the
emphasis of the paper is on construct identification and model
development. The paper enriches the existing literature by proposing
a hybrid multi objective decision model which introduces new soft
dimensions i.e. perceived distance, ethical proximity, humane
orientation to the decision process and facilitates effective decision
making.
Abstract: In the present paper, we propose numerical methods for solving the Stein equation AXC - X - D = 0 where the matrix A is large and sparse. Such problems appear in discrete-time control problems, filtering and image restoration. We consider the case where the matrix D is of full rank and the case where D is factored as a product of two matrices. The proposed methods are Krylov subspace methods based on the block Arnoldi algorithm. We give theoretical results and we report some numerical experiments.
Abstract: In recent past, the Unified Modeling Language (UML) has become the de facto industry standard for object-oriented modeling of the software systems. The syntax and semantics rich UML has encouraged industry to develop several supporting tools including those capable of generating deployable product (code) from the UML models. As a consequence, ensuring the correctness of the model/design has become challenging and extremely important task. In this paper, we present an approach for automatic verification of protocol model/design. As a case study, Session Initiation Protocol (SIP) design is verified for the property, “the CALLER will not converse with the CALLEE before the connection is established between them ". The SIP is modeled using UML statechart diagrams and the desired properties are expressed in temporal logic. Our prototype verifier “UML-SMV" is used to carry out the verification. We subjected an erroneous SIP model to the UML-SMV, the verifier could successfully detect the error (in 76.26ms) and generate the error trace.
Abstract: In order to study floristic and molecular classification
of common wild wheat (Triticum boeoticum Boiss.), an analysis was
conducted on populations of the Triticum boeoticum collected from
different regions of Iran. Considering all floristic compositions of
habitats, six floristic groups (syntaxa) within the populations were
identified. A high level of variation of T. boeoticum also detected
using SSR markers. Our results showed that molecular method
confirmed the grouping of floristic method. In other word, the results
from our study indicate that floristic classification are still useful,
efficient, and economic tools for characterizing the amount and
distribution of genetic variation in natural populations of T.
boeoticum. Nevertheless, molecular markers appear as useful and
complementary techniques for identification and for evaluation of
genetic diversity in studied populations.
Abstract: This paper describes an ongoing study into the quality of service provided by the Irish Revenue Commisioners- online tax filing and collection system. The Irish Revenue On-Line Service (ROS) site has won several awards. In this study, a version of the widely use SERVQUAL measuring instrument, adapted for use with online services, has been modified for the specific case of ROS. In this paper, the theory behind this instrument is set out, the particular problems of evaluating revenue collecting online are examined and the rationale for this approach is explained.
Abstract: A model of a system concerning one species of demersal
(inshore) fish and one of pelagic (offshore) fish undergoing fishing
restricted by marine protected areas is proposed in this paper. This
setup was based on the FISH-BE model applied to the Tabina fishery
in Zamboanga del Sur, Philippines. The components of the model
equations have been adapted from widely-accepted mechanisms in
population dynamics. The model employs Gompertz-s law of growth
and interaction on each type of protected and unprotected subpopulation.
Exchange coefficients between protected and unprotected
areas were assumed to be proportional to the relative area of the
entry region. Fishing harvests were assumed to be proportional to
both the number of fishers and the number of unprotected fish. An
extra term was included for the pelagic population to allow for the
exchange between the unprotected area and the outside environment.
The systems were found to be bounded for all parameter values. The
equations for the steady state were unsolvable analytically but the
existence and uniqueness of non-zero steady states can be proven.
Plots also show that an MPA size yielding the maximum steady state
of the unprotected population can be found. All steady states were
found to be globally asymptotically stable for the entire range of
parameter values.
Abstract: Human middle-ear is the key component of the
auditory system. Its function is to transfer the sound waves through
the ear canal to provide sufficient stimulus to the fluids of the inner
ear. Degradation of the ossicles that transmit these sound waves from
the eardrum to the inner ear leads to hearing loss. This problem can
be overcome by replacing one or more of these ossicles by middleear
prosthesis. Designing such prosthesis requires a comprehensive
knowledge of the biomechanics of the middle-ear. There are many
finite element modeling approaches developed to understand the
biomechanics of the middle ear. The available models in the
literature, involve high computation time. In this paper, we propose a
simplified model which provides a reasonably accurate result with
much less computational time. Simulation results indicate a
maximum sound pressure gain of 10 dB at 5500 Hz.
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.