
غلامرضا شهریار
حشمتی
author
text
article
2003
per
The ultraspherical polynomials form a orthogonal system on 1=[l,1] for the
measure dµ?(x)=(l_x2) ?dx for
The Gegenbauer’s multiplication formula shows that the Gegenbauer Kernel is stochastic. By means of the Gegenbauer Kernel we construct a Markov operator and by using the abstract result for a Markov Operators we prove its asymptotic stability for o ? ??½ This result will be
generalized for all ?? ½ by use of the
Harmonic analysis techniques.
University College of Engineering
دانشکده فنی
08031026
36
v.
4
no.
2003
https://jfe.ut.ac.ir/article_10161_775af15b6ca1187eca53f1cb079dafe6.pdf

احمد فیض
دیزجی
author
رامبد
رستگاری
author
text
article
2003
per
Dynamic equation of a simply supported beam with a lump mass in the midspan subjected to harmonic axial excitation, whose one end can move along the beam freely, is a nonlinear differential equation with no explicite solution. In this article we start extracting the equation of motion. Existence of periodic solution, under some condition, are investigated and proved using green function and Schaunder’s fixed point theorem; also noting into the structure of differential equation of motion, existence of oscillating response investigated, independently. By this analysis, it becomes possible to predict whether the solution converges to a point (zero) or a periodic answer.
University College of Engineering
دانشکده فنی
08031026
36
v.
4
no.
2003
https://jfe.ut.ac.ir/article_10162_cf7e27cf53957a7fca233d644bcd89b5.pdf

ابراهیم رحیم
پور
author
حمید
لسانی
author
حسین
محسنی
author
یوخن
کریستین
author
کورت
فزر
author
text
article
2003
per
The application of the transfer function is discussed at present as a method for onsite monitoring and diagnosis of power transformers with regard to mechanical damages of the winding. In order to be able to evaluate the measurements, the correlation between the characteristics of transfer functions and possible damages must be known. Radial deformation of transformer windings have been studied both experimentally and theoretically. The primary winding of the test transformer has 30 double disk coils (1.2 MVA, 10 kV) and the secondary is a one layer winding with 23 turns (1.2 MVA, 400 V). A detailed mathematical model was developed for the test object and a comparison between measured and calculated results was carried out. A numerical method for the calculation of inductances is suggested, which is independent of the shape of the windings’ turns. For the calculation of the earth capacitances a relationship is given. An independent simulation confirmed the
accuracy of this relationship by using finite elements method. It is shown that the developed model can represent the behavior of transformer windings in the frequency domain in case of sound and deformed conditions.
University College of Engineering
دانشکده فنی
08031026
36
v.
4
no.
2003
https://jfe.ut.ac.ir/article_10163_eca3e0e64dc3c89921d636cbe5608a2f.pdf

ابراهیم
کرمی
author
حمید
سلطانیانزاده
author
محمود کمره
ای
author
text
article
2003
per
Researchers have shown that appropriate heating of the cancer cells during the mitosis damages and kills them. This is referred to as hyperthermia cancer therapy. In this process, it is crucial to focus the heat on the cancerous tissue (target) so that the surrounding normal tissue is not damaged by the therapy. Several methods have been proposed for hyperthemia treatment; ultrasound is most commonly proposed and applied, and is the focus of our research. Phased arrays are the means to focus the ultrasound beam and concentrate the ultrasound energy on the target tissue. This paper presents design, development, and evaluation of our ultrasound phased array system for hyperthemia therapy. The system is controlled by a computer and consists of both hardware (phased array and electronic circuits) and computer software. Based on the effective errors measured in the system evaluation phase, we have developed approaches to mitigate the errors. These approaches add voltage and phase feedback to the system. Experimental results illustrate that the most appropriate response is obtained using the phase feedback approach.
University College of Engineering
دانشکده فنی
08031026
36
v.
4
no.
2003
https://jfe.ut.ac.ir/article_10164_95027b23af9f2a3e9bf254d23d2e259b.pdf

محمود
محسنی
author
فرهنگ جلالی
فراهانی
author
text
article
2003
per
Separtation units are one of the most important parts in the chemical processes, arid distillation towers are one of them. In recent years, reactive distillation has received a great attention in optimization of the process and has got a good development. In order to evaluate a reactive distillation system, MESH equations are solved and with the results out of this calculation, composition, temperature, and pressure are evaluated. MESH equations are nonlinear in nature and their solution is very crucial and, therefore, conventional methods are not reliable to solve this system. Therefore, in this work it has been tried to use Homotopy continuation method to find the solution. Homotopy Continuation can guarantee with any initial guess and it can be applied to other process design problem.
University College of Engineering
دانشکده فنی
08031026
36
v.
4
no.
2003
https://jfe.ut.ac.ir/article_10165_4a40e27caa6730de73e13c4d34ffe70b.pdf

چنگیز
دهقانیان
author
text
article
2003
per
University College of Engineering
دانشکده فنی
08031026
36
v.
4
no.
2003
https://jfe.ut.ac.ir/article_10166_f5fb61c7833eba1215e407f0f9d44377.pdf

محمد رضا
طلاقت
author
جلیل
اوجی
author
text
article
2003
per
The high annual rate of production of rice bran in our country usually results in accumulation of a large quantity of bran. This fact promoted us to evaluate different sample of rice bran for oil constituents. This research work was the extraction of oil from different varieties of bran collected from the North and the Southern parts of Iran. The total oil content, the quantity and their suitability for use as edible oil and/or in soap manufacturing were compared. Based on their resolution power and solvents availability, nhexane was eventually selected as the suitable decolorization using activated carbon and! or acid activated clay toward final purification. Based on our results and findings, the oil samples obtained were edible but the total oil content of the Northern samples were higher than the those collected from the South of Iran. The oil content of these samples was ranged from 1.2 to 5.3 percent. Therefore, rice bran can be considered as an alternative source of edible oil which may be used in preparation of foodstuffs and dietary supplements
University College of Engineering
دانشکده فنی
08031026
36
v.
4
no.
2003
https://jfe.ut.ac.ir/article_10167_dc6e09799c9a16f18c5660e346f3e8f2.pdf

نازنین سادات قدسی
پور
author
سید مجتبی صدر
عاملی
author
محمدرضا
امیدخواه
author
text
article
2003
per
In this work, a rotary regenerator is simulated by solving a developed mathematical model and optimized. A novel experimental rotary wheel has been designed and setup in the laboratory scale. The effects of parameters on the system performance have been investigated using an experimental design method. A new model for the system efficiency in which three parameters (rotor speed, hot and cold stream flow rates) are involved has been presented for the prediction of the rotary regenerator performance
University College of Engineering
دانشکده فنی
08031026
36
v.
4
no.
2003
https://jfe.ut.ac.ir/article_10168_69412557e3013e7d4f1fe7ff6d07c4c9.pdf

محسن
صارمی
author
احسان الدین
محلاتی
author
text
article
2003
per
The objective of present research work is study the sodium nitrite function as an anodic inhibitor on corrosion behavior of mild steel in concrete. For this purpose, cyclic potentiodynamic polarization technique was applied on steel in Simulated Concrete Pore (SCP) solution. The experimental results illustrated that the presence of nitrite ions in solution containing CF will form a passive film on the metal surface and consequently, potential of pit nucleation, Epit, would be considerably increased in positive direction. However, with increasing sodium nitrite concentration, at first the protection potential of pits, Epro, is increased and then it remained constant. For this reason the Epro didn’t come up to Epit. So the pits weren’t entirely repaired. The microscopy of the surface after cyclic polarization confirmed the electrochemical observation.
University College of Engineering
دانشکده فنی
08031026
36
v.
4
no.
2003
https://jfe.ut.ac.ir/article_10169_eb87cba5795de181391240ea34fcabae.pdf

حسن
فرهنگی
author
حمید
قاسم
author
سید شمس الدین
عابدی
author
text
article
2003
per
Effect of Hydrogen On Mechanical
Behavior, strength and ductility properties
and related fracture mechanisms in a low
carbon and low alloy 2.25 Cr I Mo
bainitic steel were studied. Entrance of
hydrogen into the microstructure was done
by cathodic charging in IN sulfuric acid
containing arsenic trioxide as a cathodic
poison. Immediately after cathodic
hydrogen charging, slow strain rate testing
(SSRT) at strain rates of 10.6 to l04s, as
well as ordinary tension test and sustained
load test were performed. Fractographic
investigation were performed using stereo
and scanning electron microscopes. The
process of hydrogen charging into the alloy
steel brings about reductions in strength
and ductility properties leading to a
completely brittle mechanical behavior.
The results of fractographic studies
showed that hydrogen induced cracking
was initiated at subsurface inclusion
matrix interfaces, which initially
propagated by an intergranular cracking
mechanism, and was followed by extensive
low energy quasicleavage mode at later
stages of crack growth. Crack growth
mechanisms under various testing
conditions are presented in a schematic
model and discussed.
University College of Engineering
دانشکده فنی
08031026
36
v.
4
no.
2003
https://jfe.ut.ac.ir/article_10170_7c0282e7e3494cf502d75f5936df6c09.pdf

دارا
معظمی
author
text
article
2003
per
Center for Theoretical Physics and
Mathematics, Atomic Energy Organization of
Iran
For any fixed integers m, n, with in m? n + 1, we consider classes of graphs G , that are nconnected with the minimum number of edges. G graphs are examples of graphs with maximum connectivity. This property makes them useful to network designers and thus it is of interest to study the behavior of other stability parameters for these gaphs. In this paper we study the tenacity of the 0
when “m” is even and “n” is odd number.
University College of Engineering
دانشکده فنی
08031026
36
v.
4
no.
2003
https://jfe.ut.ac.ir/article_10171_fa852c3a3454f56fae6094a15a22dab7.pdf