Thabt, Khaled Mohamed. Expression of Somatostatin Receptor Tupe II in Hepatocellular Carcinoma and The Therapeutic Effects of Some Herbs /

frontdotardUrban and Civil

Nov 15, 2013 (3 years and 8 months ago)

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Author:

Thabt, Khaled Mohamed.

Title:

Expression of Somatostati
n Receptor Tupe II in Hepatocellular
Carcinoma and The Therapeutic Effects of Some Herbs /


Statement of
responsibility:

Khaled Mohamed Thabt ; Supervisor Nabil Mohie Abd El
-
Hamid, Atef
Ebrahim Abd El
-
Baky, Omer Mahmoud Mohamed.

Dissertation:

ph

Abstract:

The Actively
-
controlled Constrained Layer Damping treatment ACLD
for flexible anns has been presented In this thesis. The proposed
ACLD consists of a conventional Passive Constrained Layer Damping
augmented with effective control means to contr
ol the strain of the
constrained layer, in response to the vibration of the ann. The three
-
layer composite ACLD when bonded to the vibrating surface acts as a
SMART constrained layer damping treatment with built
-
in sensing
and actuation capabilities. Propo
rtional and derivative contfollers are
used separately to control the rigid and flexible body motion of the
ann.

A finite element model is developed based on the Euler
-
Bernoulli
beam theory to study the dynamic characteristics and control of the
flexible a
nn. The model accounted for the behavior of the distributed
piezoelectric sensor and actuator. The developed beam element has
two nodes with four degrees of freedom per node to describe the
longitudinal and the transverse displacements. The combined mass,
stiffness and gyroscopic matrices obtained are utilized to compute
the natural frequency of the ann. The Runge
-
Kutta fourth order
method is utilized to simulate the response of the system under
different control inputs using the state space representation
of the
system.

The effect of adding a tip mass to the ann on the vibration damping
capability of the controller and on the dynamic response of the tip
position ill general is studied theoretically as an indication of the
robustness of the controller to par
ameter variations. It is found that
the ACLD controller is robust to the parameter variation due to the
loading conditions.

The theoretical predictions of the finite element model were
compared with the experimental measurements of the ACLD for the
arm at
a proportional gain of 425 and at different command step
angular positions. Good agreement is realized between the simulated
tip position response and the experimental step response of the arm.

The effectiveness of the ACLD treatment in damping the vibrati
on of
the flexible arm is theoretically and experimentally demonstrated at
different excitation conditions. Good attenuation characteristics are
obtained with a simple analog amplifier. Without complex digital
signal processmg. The results obtained emphasi
ze the merits of the
SMART Actively
-
controlled Constrained Layer Damping and suggest
its suitability for nwnerous other applications. Further improvements
of the characteristics of the ACLD treatment can be obtained by
augmenting the control law with a der
ivative component in order to
enhance its capabilities at high frequencies.

The use of a rigid body PD
-
controller to damp
-
out the vibration of
the flexible ann shows that, it is better to have fast motions but
smaller maneuvering angles for the arm to main
tain lower amplitude
of vibration. The experimental results obtained with the ACLD
controller show that, wider maneuvering angles can be achieved,
therefore the use of both controllers altogether is strongly
recommended to obtain faster motions and wider m
aneuvering
angles.

The development of analytical tools and modeling teclmiques which
provide more accurate and complete representation of the system
should be emphasized in future research. In particular, it is
necessary to implement various finite element

techniques and
experimental procedures to extend the work to thick arms with shear
effects. For example, the finite element model which is based on the
Euler
-
Bernoulli beam theory in this thesis needs to be replaced by
the Timoshenko’s deformation theory
to better describe the
deformation of the thick arms.

The motor dynamics of the arm should be included in the
mathematical model in the future to better describe the dynamics of
the model.

Multi
-
layers laminated composite arms should be considered to
demon
strate the feasibility and merits of the ACLD concept. Also, the
selection of the optimal control gains, robust control strategies and
shaping of the piezoelectric sensor/actuator pairs should be studied
to accommodate the tIDcertainties of the of the ACLD

parameters
and reject the effects of the noise and external disturbances in future
design research.

The application of the ACLD controller to multi
-
link flexible
manipulators should be considered, which requires the development
of a mathematical model to
describe the dynamics of the system and
experimental verification of the model.