2010
17
4
4
0
http://scientiairanica.sharif.edu/3324.html
Gauss Integration Singular Integrals of BEM for Geometrically Linear ElementsLimits in Nearly
2
2
The most suitable and widely used numerical integration method for boundary integrals
in the BEM method is GaussLegendre integration. But, this integration method is not appropriate
for singular and nearly singular integrations in BEM. In this study, some criteria are introduced for
recognizing nearly singular integrals in the integral form of the Laplace equation. At the rst stage,
a criterion is obtained for the constant element and, at the later stages, higher order elements are
investigated. In the present research, the Romberg integration method is used for nearly singular
integrals. The results of this numerical method have good agreement with analytical integration. The
singular integrals are solved by composing the Romberg method and midpoint rule. Constant, linear
and other interpolation functions of potentials over an element are a category of BEM elements. In
those elements, the GaussLegendre integration will be accurate if the source point is placed out of
the circle with a diameter equal to element length, and its center matched to the midpoint of the
element.
2
The most suitable and widely used numerical integration method for boundary integrals
in the BEM method is GaussLegendre integration. But, this integration method is not appropriate
for singular and nearly singular integrations in BEM. In this study, some criteria are introduced for
recognizing nearly singular integrals in the integral form of the Laplace equation. At the rst stage,
a criterion is obtained for the constant element and, at the later stages, higher order elements are
investigated. In the present research, the Romberg integration method is used for nearly singular
integrals. The results of this numerical method have good agreement with analytical integration. The
singular integrals are solved by composing the Romberg method and midpoint rule. Constant, linear
and other interpolation functions of potentials over an element are a category of BEM elements. In
those elements, the GaussLegendre integration will be accurate if the source point is placed out of
the circle with a diameter equal to element length, and its center matched to the midpoint of the
element.
Keywords: Boundary element method; GaussLegendre integration; Laplace equation; Nearly singular
integrals; Romberg integration
0
0


M.
Ghodsi
Department of Civil Engineering,Sharif University of Technology
Iran
email@email.com


M.
Abbaspour
Department of Mechanical Engineering,Sharif University of Technology
Iran
mabbaspour@jamejam.net
Boundary element method
GaussLegendre integration
Laplace equation
Nearly singular integrals
Romberg integration
http://scientiairanica.sharif.edu/3325.html
Comparison of the Mollification Method, Wavelet Transform and Moving Average Filter for Reduction of Measurement Noise Effects in Inverse Heat Conduction Problems
2
2
This paper proposes a procedure to smooth temperature data by wavelet transform, moving
average filter and the mollification method prior to utilizing the IHCP methods (i.e. the conjugate gradient
method, the Tikhonov regularization method) for unknown heat
ux estimation. The measured transient
temperature data utilized in the solution may be obtained from locations inside the body or from locations
on its inactive boundaries. Two case studies are used to investigate the eciency and accuracy of the
mentioned procedure. The first case study is performed on a rectangular body. The second case study
demonstrates the ability of the proposed method to estimate heat
ux in a more complicated geometry.
Smoothing measured data causes an increase in the accuracy and stability of the estimation.
2
This paper proposes a procedure to smooth temperature data by wavelet transform, moving
average filter and the mollification method prior to utilizing the IHCP methods (i.e. the conjugate gradient
method, the Tikhonov regularization method) for unknown heat
ux estimation. The measured transient
temperature data utilized in the solution may be obtained from locations inside the body or from locations
on its inactive boundaries. Two case studies are used to investigate the eciency and accuracy of the
mentioned procedure. The first case study is performed on a rectangular body. The second case study
demonstrates the ability of the proposed method to estimate heat
ux in a more complicated geometry.
Smoothing measured data causes an increase in the accuracy and stability of the estimation.
Keywords: Mollification method; Wavelet transform; Moving average filter; Estimated heat
ux;
Conjugate gradient method; Tikhonov regularization method.
0
0


S.
D. Farahani
Department of Mechanical Engineering,University of Tehran
Iran
hbsidgwj@scientiaunknown.non


F.
Kowsary
Department of Mechanical Engineering,University of Tehran
Iran
htdxdixy@scientiaunknown.non
mollification method
wavelet transform
Moving average filter
Estimated heat ux
conjugate gradient method
Tikhonov regularization method
http://scientiairanica.sharif.edu/3326.html
Experimental Investigation of Bae Eect on the Flow in a Rectangular Primary Sedimentation Tank
2
2
In primary sedimentation tanks, shortcircuiting enlargement of dead zones and high
ow mixing problems are caused by circulation regions (dead zones), which can reduce the optimal
sedimentation of particles. For proper design of such tanks, the formation of recirculation zones should be
avoided. The provision of a bae as a geometrical modication of a tank may in
uence the
ow eld for
better sedimentation. Thus, in this study, velocity measurements were performed by a threedimensional
Acoustic Doppler Velocimeter (ADV) to investigate bae eects on the velocity distribution in a primary
rectangular sedimentation tank, quantitatively. Eects of bae positioning were also determined. Mean
ow analysis shows how a bae can alter the hydrodynamics of the
ow eld. It was quantitatively found
that the intermediate bae not only in
uences the
ow eld in its downstream, but also aects the
ow
pattern in its upstream. It was found that the bae setting and its position relative to the inlet and
outlet in
uences the
ow eld and the development of
ow. Baed
ow may provide better conditions for
sedimentation by in
uencing velocity proles. However, further detailed experimental study is necessary
to fully capture the bae eect and obtain further insight into the complex
ow eld in a sedimentation
tank.
2
In primary sedimentation tanks, shortcircuiting enlargement of dead zones and high
ow mixing problems are caused by circulation regions (dead zones), which can reduce the optimal
sedimentation of particles. For proper design of such tanks, the formation of recirculation zones should be
avoided. The provision of a bae as a geometrical modication of a tank may in
uence the
ow eld for
better sedimentation. Thus, in this study, velocity measurements were performed by a threedimensional
Acoustic Doppler Velocimeter (ADV) to investigate bae eects on the velocity distribution in a primary
rectangular sedimentation tank, quantitatively. Eects of bae positioning were also determined. Mean
ow analysis shows how a bae can alter the hydrodynamics of the
ow eld. It was quantitatively found
that the intermediate bae not only in
uences the
ow eld in its downstream, but also aects the
ow
pattern in its upstream. It was found that the bae setting and its position relative to the inlet and
outlet in
uences the
ow eld and the development of
ow. Baed
ow may provide better conditions for
sedimentation by in
uencing velocity proles. However, further detailed experimental study is necessary
to fully capture the bae eect and obtain further insight into the complex
ow eld in a sedimentation
tank.
Keywords: ADV; Intermediate bae; Sedimentation tank; Primary settling tank; Reverse
ow region.
0
0


B.
Firoozabadi
Department of Mechanical Engineering,Sharif University of Technology
Iran
email@email.com


H.
Jamshidnia
Department of Mechanical Engineering,Sharif University of Technology
Iran
dvewlwkg@scientiaunknown.non
ADV
Intermediate bae
Sedimentation tank
Primary settling tank
Reverse ow region
http://scientiairanica.sharif.edu/3327.html
Classification of Mean Arterial Pressure Regimes in ICU Using a ModelBased Support Vector Machine: Acute Hypotensive, Critical and Survival Episodes
2
2
In this study, a new pattern discrimination method for the classication of Mean Arterial
Pressure (MAP) regimes in ICU via an appropriately regulated Radial Basis Function (RBF) Support
Vector Machine (SVM) is described. The aim of this classication is to detect hazardous cardiogenic
shock situations to prevent probable fatal failure of organs. To this end, rst, electrocardiogram (ECG)
and Blood Pressure (BP) waveforms are processed via a Modied Hilbert Transform (MHT), and QRS
complexes (equivalently obtaining heart rateHR trend) and pressure pulses (equivalently obtaining trends
of systolic, diastolic and mean arterial pressures) are detected, respectively. In the next step, a RBFSVM
classier is tuned using features obtained from the cardiogenic shock risk scoring model developed by
Hasdai et al. (2000) to classify MAP regimes into three categories; survival (the status that will not fall
into shock), critical (the transient status that may lead to shock or a return to the survival episode) and
Acute Hypotensive Episode AHE (meaning cardiogenic shock will certainly occur.) Then, the regulated
RBFSVM classier is applied to 60 records of the Computers in Cardiology (CinC) Challenge 2009 and
the values of Se = 92% and P+ = 93% are obtained for sensitivity and positive predictivity, respectively.
As some results of this study, the proposed classication method recognized truly 15 subjects out of 15
normal (without shock episodes) subjects of the MIMICII database as belonging to the survival class",
while the algorithm could classify 24 subjects as AHE", 3 subjects as of the critical class" and 3 subjects
as in the survival" situation out of 30 shock containing records of the MIMICII database.
2
In this study, a new pattern discrimination method for the classication of Mean Arterial
Pressure (MAP) regimes in ICU via an appropriately regulated Radial Basis Function (RBF) Support
Vector Machine (SVM) is described. The aim of this classication is to detect hazardous cardiogenic
shock situations to prevent probable fatal failure of organs. To this end, rst, electrocardiogram (ECG)
and Blood Pressure (BP) waveforms are processed via a Modied Hilbert Transform (MHT), and QRS
complexes (equivalently obtaining heart rateHR trend) and pressure pulses (equivalently obtaining trends
of systolic, diastolic and mean arterial pressures) are detected, respectively. In the next step, a RBFSVM
classier is tuned using features obtained from the cardiogenic shock risk scoring model developed by
Hasdai et al. (2000) to classify MAP regimes into three categories; survival (the status that will not fall
into shock), critical (the transient status that may lead to shock or a return to the survival episode) and
Acute Hypotensive Episode AHE (meaning cardiogenic shock will certainly occur.) Then, the regulated
RBFSVM classier is applied to 60 records of the Computers in Cardiology (CinC) Challenge 2009 and
the values of Se = 92% and P+ = 93% are obtained for sensitivity and positive predictivity, respectively.
As some results of this study, the proposed classication method recognized truly 15 subjects out of 15
normal (without shock episodes) subjects of the MIMICII database as belonging to the survival class",
while the algorithm could classify 24 subjects as AHE", 3 subjects as of the critical class" and 3 subjects
as in the survival" situation out of 30 shock containing records of the MIMICII database.
Keywords: Acute hypotensive episode; Cardiogenic shock; Blood pressure pulse detection; Piecewise
polynomial tting; Support vector machine; Risk scoring model.
0
0


M.R.
Homaeinezhad
Department of Mechanical Engineering,Khajeh Nasire Toosi University of Technology
Iran
wjxjlfay@scientiaunknown.non


A.
Ghaffari
Department of Mechanical Engineering,Khajeh Nasire Toosi University of Technology
Iran
ilhhnxgu@scientiaunknown.non


M.
Akraminia
Department of Mechanical Engineering,Khajeh Nasire Toosi University of Technology
Iran
dukywnhb@scientiaunknown.non


M.
Atarod
Department of Mechanical Engineering,Khajeh Nasire Toosi University of Technology
Iran
xpwzdqve@scientiaunknown.non


R.
Rahmani
Department of Mechanical Engineering,Khajeh Nasire Toosi University of Technology
Iran
sjpuamwz@scientiaunknown.non
Acute hypotensive episode
Cardiogenic shock
Blood pressure pulse detection
Piecewise polynomial tting
support vector machine
Risk scoring model
http://scientiairanica.sharif.edu/3328.html
Optimal Trajectory Planning with the Dynamic Load Carrying Capacity of a Flexible CableSuspended Manipulator
2
2
This paper presents an indirect method for computing optimal trajectory, subject to robot
dynamics,
exibilities and actuator constraints. One keyissue that arises from mechanism
exibility is
nding the Dynamic Load Carrying Capacity (DLCC). The motion planning problem is rst formulated
as an optimization problem, and then solved using Pontryagin's minimum principle. The basic problem
is converted to the TwoPoint Boundary Value Problem (TPBVP), which includes joint
exibility. Some
examples are employed to compare three models, dynamic,
exible joint, and rigid. The results illustrate
the eectiveness of this indirect method.
2
This paper presents an indirect method for computing optimal trajectory, subject to robot
dynamics,
exibilities and actuator constraints. One keyissue that arises from mechanism
exibility is
nding the Dynamic Load Carrying Capacity (DLCC). The motion planning problem is rst formulated
as an optimization problem, and then solved using Pontryagin's minimum principle. The basic problem
is converted to the TwoPoint Boundary Value Problem (TPBVP), which includes joint
exibility. Some
examples are employed to compare three models, dynamic,
exible joint, and rigid. The results illustrate
the eectiveness of this indirect method.
Keywords: Path planning; Payload; Flexible cablesuspended manipulator; Optimal control; Two point
boundary value problem
0
0


M. H.
Korayem
Department of Mechanical Engineering,Iran University of Science and Technology
Iran
hkorayem@iust.ac.ir


M.
Bamdad
Department of Mechanical Engineering,Iran University of Science and Technology
Iran
dmjvaurk@scientiaunknown.non


E.
Davarzani
Department of Mechanical Engineering,Iran University of Science and Technology
Iran
vdqtcrbh@scientiaunknown.non
Path planning
Payload
Flexible cablesuspended manipulator
Optimal control
Two point boundary value problem
http://scientiairanica.sharif.edu/3329.html
Surface Characterization of Through Cage Plasma Nitriding on the Surface Properties of Low Alloy Steel
2
2
DIN 1.6580 low alloy steel has been plasma nitrided using the novel Through Cage (TC)
plasma nitriding technique. Experimental results show that the thickness of the compound layer increases
with temperature, as well as nitrogen percent, in the gas mixture, that an increase in screen hole size has
no eect on the compound layer thickness under screen top lid conditions and, also, that an increase in
screen hole size at the same temperature results in an increase in the thickness of the compound layer
under iron plate top lid conditions. The results of microhardness measurements indicate that surface
hardness increases with temperature, as well as nitrogen volume, in the treatment gas. It was also found
that the hardness values obtained using a screen top lid are relatively greater than those obtained using
an iron plate top lid.
2
DIN 1.6580 low alloy steel has been plasma nitrided using the novel Through Cage (TC)
plasma nitriding technique. Experimental results show that the thickness of the compound layer increases
with temperature, as well as nitrogen percent, in the gas mixture, that an increase in screen hole size has
no eect on the compound layer thickness under screen top lid conditions and, also, that an increase in
screen hole size at the same temperature results in an increase in the thickness of the compound layer
under iron plate top lid conditions. The results of microhardness measurements indicate that surface
hardness increases with temperature, as well as nitrogen volume, in the treatment gas. It was also found
that the hardness values obtained using a screen top lid are relatively greater than those obtained using
an iron plate top lid.
Keywords: Plasma nitriding; Through Cage Plasma Nitriding (TCPN); Active screen; Compound layer;
Low alloy steels.
0
0


F.
Taherkhani
Department of Mechanical Engineering,Azad University
Iran
vygxtsxo@scientiaunknown.non


A.
Taherkhani
Department of Mechanical Engineering,Azad University
Iran
mkamaxoz@scientiaunknown.non
Plasma nitriding
Through Cage Plasma Nitriding (TCPN)
Active screen
Compound layer
Low alloy steels