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Fatigue Behavior of Piezoelectric Ceramics Material

Thesis Info

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Author

Pasha, Riffat Asim

Program

PhD

Institute

University of Engineering and Technology

City

Taxila

Province

Punjab

Country

Pakistan

Thesis Completing Year

2009

Thesis Completion Status

Completed

Subject

Applied Sciences

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1389

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726199289

Similar


Piezoelectric ceramics materials are extensively used in many electromechanical systems as sensing and actuating devices. The performance of these devices deteriorates due to cyclic loading either mechanical, electrical, electromechanical, thermo-mechanical, and under thermal shocking conditions. Earlier the effect of electrical and mechanical cycling loadings on the functional performance has been investigated. The properties of commercial lead zirconate titanate degrade during such cycling. However degradation phenomenon of piezoelectric material during thermal shocking is still an area which has to be explored. The decay in functional properties of materials is somewhat called degradation and this terminology used to describe the loss in performance with time due to stress and temperature. The common phenomenon of degradation is aging of the material, which affects the performance of the material with time. This change in performance is thought to be due to re-orientation of dipoles in different configurations. Environment is another degradation phenomenon influence the performance of piezo devices. Output performance of piezoelectric materials changes frequently with the change in temperature, pressure, humidity and moisture. Recently many studies show that water has the profound effect on the performance of piezoelectric materials. Reliability of these smart materials is important and hence there is a requirement to have an extensive study on its functional performance and properties. In actuators mostly disc shaped piezoelectric are used due to their improved properties. A part of this particular research work was to investigate the degradation of thin lead zirconate titanate piezoelectric discs through a series of experimentation to observe its function at variable frequencies in simple tap water, de-ionized water and sodium chloride (NaCl) solutions. Output viperformance has been monitored in real time as peak-peak voltage change. PZT disc found sensitive in performance in various solutions at different frequencies. The results obtained can be utilized as qualitative data for designing of micro electro- mechanical systems. The change in capacitance has been measured by using relevant instrumentation during thermal shocking in de- ionized water. The change in capacitance is a measure of dielectric constant and other piezoelectric properties. Dielectric constant, impedance, tangent loss and dissipation factors are the required parameters and can be measured by using suitable size and shape of piezoelectric materials. In general, piezoelectric ceramics posses the largest electromechanical coupling factor, dielectric constant and lowest dielectric loss. The sudden change in temperature may experience a thermal stress which further changes its above stated properties. Most of the properties are attributed to change in capacitance values at resonance and anti resonance frequencies. In a part of this research work, focus was to determine the various piezoelectric properties by thermal shocking in de-ionized water at resonance frequencies. In another phase piezoelectric ceramics disc has been investigated for its sensitivity at different temperatures and at different frequencies and resistances. A model has been developed to indicate the effect of resistance band at different temperatures. The model of performance characteristics of thin PZT disc under different temperature conditions is a unique finding and may used in selection of particular frequency and resistance range for many piezo devices for the stated conditions. The objective of this research work was to explore the degradation of thin PZT piezoelectric ceramics disc in its performance and change of various piezoelectric viiproperties during thermal cycling and shocking. The present work uncovers the various unattended thermal cycling and shocking condition of stated piezoelectric material. Comprehensive data obtained by real time experimentation may useful for designing of various micro-electromechanical systems.
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یونس فریدی احوال و آثار

یونس فریدی: احوال و آثار
مکمل نام: محمد یونس
قلمی نام: یونس ؔفریدی
تخلص: یونس ؔ
پیدائش:
یونس ؔ ؔفریدی۴ اگست ۱۹۵۵ء بروز جمعرات شہرِ فریدؒ(پاکپتن شریف) کے محلہ ’’غلہ منڈی‘‘میں پیدا ہوئے۔ان کے والد کا نام چودھری ولی محمدہے۔ایک معزز آرائیں گھرانے سے تعلق رکھتے ہیں۔
شروع شروع میں ان کا نام’’محمد اصغر‘‘ رکھا گیا اور بلدیہ میں بھی اسی نام کا اندراج کروایا گیا۔ بعد میں سرداراں بی بی (پھوپھی) نے نام محمد یونس رکھا جو آج تک ان کی پہچان کا باعث ہے اور اسی نام سے پکارے جاتے ہیں۔(۱)
پھر بعد میں حضرت بابا فرید الدین مسعود گنج شکر رحمتہ اللہ علیہ کے ساتھ دلی عقیدت اور نسبت کے باعث نام کے ساتھ ’’فریدی‘‘ لکھنا شروع کیا۔یونسؔ فریدی اس بارے میں کہتے ہیں:
’’اپنے نام کے ساتھ فریدی میں نے خود ہی لکھنا شروع کردیا تھا۔ میرے ایک استادِ گرامی! نے پوچھا فریدی کے کیا معنی ہیں؟ اور تم نے کیوں لگایا ہے اپنے نام کے ساتھ؟ میں نے عرض کی جناب معنی تو مجھے نہیں معلوم لیکن مجھے یہ اچھا لگتا ہے۔سو میں نے لگا دیا۔ اور پھر بعد میں جب میرے شعور کی آنکھ کھلی تو میرا رجحان تصوف کی طرف ہو گیا۔ اور حضرت بابا فرید رحمتہ اللہ علیہ سے دلی عقیدت ہو گئی جو آج بھی ہے۔ اب تو مکمل فریدی ہو گیا ہوں۔ہاں بچپن میں اپنے والدِ گرامی کے ساتھ دربار شریف حاضری دیا کرتا تھا۔‘‘(۲)
یونس اپنے نام کے ساتھ فریدی لکھے بغیر اپنے نام کو ادھورا سمجھتے ہیں اور نام کے ساتھ فریدی لکھنا فخر محسوس کرتے ہیں۔یعنی محمد یونس سے تب سے اب تک محمد یونس ؔفریدی لکھنا اپنی اصل پہچان کا باعث سمجھتے ہیں۔
خاندانی پس ِ منظر:
جب یونس ؔ ؔفریدی کے شعور کی آنکھ کھلی تو وہ دیکھتے ہیں کہ ان...

امام جلال الدین السیوطی رحمہ اللہ کی زندگی اور علم تصوف میں خدمات

The Almighty Allah has sent many intellectual and pious people after the Last Prophet and Messenger Allah Subhan-o-Tala for the security of Den-e-Islam. They not noly Protect Deen-e-Islam from the foreign imovation but take their roles in its world over spreading. One among these prestigious personalities and intellectual is Jalal Ud Din Asoyothi (849-911). He was a multi sided personality. At the same time he was a great scholar, Author, Reviewer and genius intellectual among his friends. You are the author of approximately 700 books. He has touched my aspect of life in written works. While having such a busy and prestigious life of honesty, truthfulness, rejecting the materialistic life having a heart for the spiritual life. He started to leads the life of mysticism and till death did not leave the life of mystics persons. In this mystic’s life he has written and review many books. Due to this mysticism he was serves the humanity and protect Deen-e-Islam from the false beliefs. In this research paper some of the aspect of mysticism in the light of his research works has been discussed.

Cost-Effectiveness Comparison of Distance Education in Indonesia, Bangladesh and Pakistan

The significant objectives of this study were; to examine and calculate the total and average costs of each selected item, to calculate student’s opportunity costs, to analyse student’s satisfaction with programme, to analyse the cost effective measures taken by academicians for each of three programmes and to assess eleven years admissions and completion and to analyse main objectives of programmes. It was descriptive study based on analysis and comparison of B.Ed programme at Bangladesh Open University (BOU), B.Ed at Allama Iqbal Open University (AIOU) Pakistan, and degree level/SI teacher training programme at University Terbuka (UT) Indonesia. It used a simple non-linear input and output design of “economic approach” of cost effectiveness analysis. The instruments that were developed to collect data about costs and other relevant features of programme were questionnaires. There were two questionnaires. The first questionnaire was administered to the management of programme. The elements in first questionnaire were; 1-Enrolment, 2-completion, 3-costs of examinations, 4- costs of radio and television transmissions, 5-course presentation costs (tutorial and workshop), 6- costs of printed material, 7-departmental/ establishment costs, 8- cost of building meant for this programme in the main campus of university, 9- objectives of programme and analyses about achievement of objectives, 10-benrolment and completion since 1992 to 2002. viiiThe selected output variables for cost-effectiveness analysis were; (a) Completion rate (b) Student’s satisfaction with programme. (C) The most important objectives of each selected programme were analyzed separately. Independent variables for data analysis were university, gender, age, qualification at the time of admission, profession and who paid the opportunity cost of students. The dependent variables for data analysis were student’s satisfaction with programme and student’s opportunity cost. The purpose to add some queries about the preliminary information was to obtain some of background knowledge about programme. Unit cost per pupil was the criteria for cost effectiveness analysis. The cost function applied for data analysis was; Unit cost = Fixed cost + Variable costs / N The results showed that enrolment was the highest at AIOU during 11 years. The highest average costs of examination were; 93.36 (UT), costs of course presentation were 93.46 (UT), costs of printed material were 98.97 (BOU), and departmental costs were 78.76 (BOU). Radio and television department produced programmes for students of BOU. Average cost of broadcast media was .851 at UT. As far as unit cost per student is concerned it was the lowest at AIOU. The mean scores of total opportunity costs were 411 for UT, 227 for BOU and 458 for AIOU. Student’s satisfaction with programme was highest at UT and lowest at BOU. The result showed that unit cost was lowest at AIOU and programme was the most cost effective due to economy of scale. Income from fee of each programme and item wise costs should be maintained in documents so that the assessment and comparison of programme may be feasible for management and researchers. The cost of examination is high at UT as compared to the other two universities. It is better to work out to lower down the cost of examination at UT. Costs of broadcast media at AIOU are in the margin. AIOU may spend on transmissions for all students of B. Ed. The costs of print and Department at UT are the lowest. AIOU and BOU can benchmark for lower down costs of print and department.