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Vibration Characteristics of Fluid-Filled Functionally Graded Cylindrical Shells on Elastic Foundations

Thesis Info

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Author

Shah, Abdul Ghafar

Program

PhD

Institute

The Islamia University of Bahawalpur

City

Bahawalpur

Province

Punjab

Country

Pakistan

Thesis Completing Year

2011

Thesis Completion Status

Completed

Subject

Mathemaics

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1842

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727661499

Similar


Cylindrical shells are fundamental and core structural elements in various fields of engineering and technology. They have been extensively used for the purpose of load- carrying in the past. Recently they have acquired a paramount and valuable place in practical applications constructing gas cylinders, pressure vessels, boilers, pipe lines, arch dams, submarines, tunnels, missiles and so on. Prior to their practical uses, their different dynamical aspects, such as vibration, buckling, and stability have been studied analytically to avoid any fatigue and risk that may implicate a physical system. Particularly, the analyses of their vibration characteristics have attracted the attention of theoretical researchers in recent years for their vital uses. In this dissertation, vibrations of cylindrical shells are investigated by involving Winkler and Pasternak elastic foundations. Fluid loading terms are also introduced to examine the influence of fluids on the shell vibrations. The present shells are considered to be constructed from isotropic and functionally graded materials. The vibrations of functionally graded cylindrical shells with exponential volume fraction law are investigated. Shell frequencies are varied by changing the bases of the law. The shell problem is solved by employing the Rayleigh-Ritz method for the simply supported boundary conditions. It is found that both the values of bases and exponents of the volume fraction law influence the frequencies of the shell. The vibration characteristics of functionally graded cylindrical shells based on the Winkler and Pasternak foundations are investigated. The Wave Propagation approach has been utilized to solve the shell dynamical equations. It is found that the influence of these elastic foundations is more pronounced for the circumferential wave numbers (n). Shell frequencies increase as the circumferential wave number is increased. Also the vibration analysis of fluid-filled cylindrical shells as well as fluid-filled functionally graded cylindrical shells resting on elastic foundations is examined. It is noted that the fluid-loading terms reduce frequencies of fluid-filled cylindrical shells to almost up to half of their corresponding values for empty cylindrical shells. It is concluded that the natural frequencies of the functionally graded cylindrical shells are greatly affected when the shells are filled with fluid and placed on elastic foundations. Three research papers of the author have been published in internationally recognized journals and one is accepted.
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حکیم حبیب الرحمن

حکیم حبیب الرحمن مرحوم ڈھاکہ
ڈھاکہ کے متعدد دوستوں کے خطوط سے یہ معلوم کرکے بڑا افسوس ہوا کہ بنگال کے جادو نگار ادیب اور نادرۂ روزگار طبیب شفاء الملک حکیم حبیب الرحمن نے یکم ربیع الثانی ۱۳۶۶؁ھ کی شب میں ضغطہ دم (بلڈ پریشر) کی بیماری میں سنہ قمری سے اڑسٹھ اور شمسی سے چھیاسٹھ برس کی عمر میں دفعتہ وفات پائی، مولانا ظفر احمد صاحب عثمانی تھانوی اپنے والا نامہ میں لکھتے ہیں:
’’آپ کو وفیات لکھنے میں ملکہ ہے ایک اور وفات نامہ معارف میں لکھ دیجیے، آپ کے اور میرے مخلص دوست حکیم حبیب الرحمن صاحب کا یکم ربیع الثانی ۱۳۶۶؁ھ مطابق ۲۳؍ فروری ۱۹۴۷؁ء کی شب میں دفعتہ بلڈ پریشر بڑھ جانے سے انتقال ہوگیا، اناﷲ۔
مرحوم حضرت حکیم الامت تھانویؒ کے ابتدائی صرف ونحو کے شاگرد اور بڑے عاشق تھے، علامہ شبلی کے دوستوں میں تھے، مسلم لیگ کی جب بنیاد ۱۹۰۶؁ء میں ڈھاکہ میں رکھی گئی اور نواب سر سلیم اﷲ خان اس کے صدر ہوئے تو مرحوم جوائنٹ سکریڑی ہوئے تھے، علم طب حکیم عبدالمجید خان صاحب سے حاصل کیا، اور اس میں کمال کا درجہ پایا، بنگال میں اس وقت ان کے درجہ کا کوئی طبیب نہیں سنا گیا، ڈھاکہ میں طبیہ کالج قائم کیا، اور بڑی ہمت سے اس کو چلانے سے گورنمنٹ نے شفاء الملک کا خطاب دیا، جس کو ( لیگ کی تحریک کی بنا پر) ستمبر میں واپس کردیا‘‘۔
ان کے اس کالج سے بہت سے اطبا پیدا ہوئے اور اب بھی سلسلہ درس جاری ہے اور خدا کرے برابر جاری رہے۔
مولانا شبلی مرحوم مسلم ایجوکیشنل کانفرنس کے سالانہ اجلاس کے سلسلہ میں ۱۹۰۶؁ء میں ڈھاکہ تشریف لے گئے تھے، وہاں سے دو دوستوں کے نام ہم لوگوں کے لیے تحفہ میں اپنے ساتھ لائے، ایک کا نام مرزا فقیر محمد صاحب...

اسلام میں امن اور دہشت گردی کا تصور: ایک علمی اور تحقیقی جائزہ

Islam is the religion of peace as is evident from the very meaning of  the word Islam which is derived from root word \" salam\" meaning peace and obedience. The advent of Islam has been a pannaca for all humanity and, ever since its inception, it has the distinction of contributing more and more to the betterment and progress of humanity. Its statute is crystal clear over all religions and systems. But unfortunately, there has been a systematic campaign to present Islam as a religion of violence. The  orientalists who tend  to misinterpret Islam by relying on some injunctions without looking into their specific context. The international media, under the influence of Jews, is also spreading a false propaganda. Moreover, certain elements with in Islamic world are also providing ample opportunity for the same. In such circumstances there is a dire  need to present the true spirit of Islam but such attempts are lacking in the Muslim world despite that it is one  of the major concern, This research paper is an attempt to present Islam in its true spirit in light of holy Quran and Sunnah. It is hoped that it would pave way for further research in the field.

Biodiversity and Medicinal Valus of Vascular Plants for Sustainable Livelihood Security of Malam Jabba Valley, Hindukush Range Swat, Pakistan

(A) TAXONOMIC STUDIES (VASCULAR PLANT BIODIVERSITY) The Malam Jabba Valley, district Swat has a diverse flora with the spectacular scenic beauty that attracts tourists across the globe and makes the valley a paradise for the nature lovers and adventure seekers. Floristically the area is located in Hindukush Range, dominated by Sino- Japanese type of vegetation. A detailed investigation was carried out during 2013-2017 in order to explore and determine the vascular plant biodiversity and their conservation value based on native, naturalized, cultivated/alien species for sustainable livelihood security of Malam Jabba Valley, Hindukush Range, District Swat, Pakistan. The study documented 476 taxa of vascular plants taxonomically segregated into 334genera and 112 families. Pteridophytes were represented by 26 species classified among 14 genera and 10 families. Gymnosperms consisted of 11 species in 9 genera belonging to 4 families. Angiosperms were represented by 98 families, of these; 86 species of 69 genera in 16 families were monocots while 353 species distributed within 242 genera in 82 families were dicots. The number of plant species per family varies from 1 to 51. Athyraceae with 5 species and 3 genera was recognized as leading family in Pteridophyta followed by Adiantaceae, Aspleniacae, Dryopteridaceae and Pteridaceae with 4 species each while the remaining five families, Dennstaedtiaceae, Equisetaceae, Marsileaceae, Selaginellaceae, Thelypteridaceae were monospecific that contributes one species and one genus each. Pinaceae was prominent family in term of species diversity having 6 species and 4 genera followed by Cupressaceae with 3 species and 3 genera, Ephedraceae and Taxaceae comprising of two genera and each genus with single species. In monocots, the leading family was Poaceae with 51 species and 43 genera followed by Cyperaceae with 9 species and 5 genera, Araceae 5 species and 3 genera, Alliaceae, Asparagaceae and Liliaceae 3 species each, Alismataceae, Amaryllidaceae and Iridaceae 2 species each. Seven families (single species each) are represented by Asphodelaceae, Colchicaceae, Commelinaceae, Dioscoreaceae, Hyacinthaceae, Juncaceae and Smilacaceae. Asteraceae with 41 species and 32 genera was the key prominent family in term of species diversity in dicots followed by Rosaceae with 29 species and 15 genera; Papilionaceae 21 species and 13 genera; Lamiaceae 20 species and 15 genera; Brassicacaceae 17 species and 13 genera; Ranunculaceae 15 species and 8 genera; Solanaceae 12 species and 8 genera; Apiaceae 11 species and 10 genera; Euphorbiaceae 9 species and 4 genera; Polygonaceae 8 species and 5 genera. Four families Moraceae, Scrophulariaceae, Boraginaceae and Cucurbitaceae are represented by 7 species each. Geraniaceae are represented by 6 species and 2 genera followed by Gentianaceae, Rutaceae and Urticaceae with 5 species each. Eight families are represented by Amaranthaceae, Balsaminaceae, Chenopodiaceae, Crassulaceae, Myrtaceae, Primulaceae, Rhamnaceae and Salicaceae which contribute 4 species each. Nine families viz. Acanthaceae, Asclepiadaceae, Caryophyllaceae, Fagaceae, Malvaceae, Oleaceae, Papaveraceae, Rubiaceae and Violacea are identified with 3 species each. Fifteen families Aizoaceae, Anacardiaceae, Buxaceae. Campanulaceae, Caprifoliaceae, Convolvulaceae, Ebenaceae, Guttiferae, Mimosaceae, Onagraceae, Plantaginaceae, Thymelaeaceae, Verbenaceae, Vitaceae and Zygophyllaceae are represented by 2 species each while the remaining 32 families were monogeneric and monospecific which contribute only one genus and one species each. These families were represented by Apocynaceae, Araliaceae, Berberidaceae, Betulaceae, Buddlejaceae, Caesalpiniaceae, Canabinaceae, Celastraceae, Cuscutaceae, Elaeagnaceae, Fumariaceae, Hamamelidaceae, Hippocastinaceae, Juglandanceae, Meliaceae, Myrsinaceae, Nyctaginaceae, Oxalidaceae, Paeoniaceae, Plantanaceae, Plumbaginaceae, Podophyllaceae, Polemoniaceae, Polygalaceae, Punicaceae, Sambucaceae, Sapindaceae, Sapotaceae, Saxifragaceae, Simaroubaceae, Ulmaceae and Valerianaceae. The most important and leading taxonomic groups in term of species percentage are Dicots with a share of (74%), followed by Monocots (18.0%), Pteridophytes (6%) and Gymnosperms (2%). Herbaceous layer (286 species) was found to be the most used life form followed by shrubs (64 species), trees (58 species), grasses (51 species), climbers (16 species) and parasitic herb (01 species) in descending order. Four hundred and thirty plant taxa (90 %) of the total flora in the area are wild while the remaining 46 taxa (10 %) are cultivated or exotic species. (B) CONSERVATION STUDIES A detailed investigation was carried out during 2013-2017 in order to determine conservation status of vascular plant biodiversity for sustainable livelihood security of Malam Jabba Valley (MJV), Hindukush Range, District Swat, Pakistan. The conservation status of 430 vascular plants from 306 genera and 110 families were determined. The criteria used were those recommended by the “International Union for the Conservation of Nature” at regional and national levels (IUCN 2003, 2012a). The assessment was based on their status within MJV. Thirty species were assessed as Critically Endangered (CR), 34 species Endangered (EN), 46 species Vulnerable (VU), 78 species Near Threatened (NT), 200 species Least Concern (LC) and 42 species Data Deficient (DD). Among threatened species, the leading taxonomic groups in term of species percentage were Dicots with a share of (78%) followed by Monocots (13 %), Gymnosperms (08%) and Pteridophytes (01%). A major decline in plant biodiversity is due to some ecological factors such as habitat degradation, habitat loss, ruthless deforestation, high consumption of plant resources for fuel wood, timber and medicinal purposes, unscientific extraction of plants, influx of excessive tourism, introduced/alien species, attack of pathogens, environmental related natural disaster and hazards, developmental works, population explosion and their anthropogenic activities. Poverty, ignorance, lack of scientific knowledge, overharvesting and deforestation also create biotic pressure on the woody plant resources and result is degradation of environment. Some of the highly valuable indigenous trees like Cedrus deodara, Abies pendrow, Picea smithiana and Taxus wallichiana are in danger of local extinction if proper conservation measurements are not taken in the near future. Conservation measures are needed on urgent basis to protect threatened and economically important trees from local extinction. Awareness program about the importance of the indigenous flora, environmental education regarding sustainable harvesting, conservation practices and long term management of important and globally rich plant resources are very crucial for the sustainable livelihood security of the local community for present and future generation. There is also a need to protect the vascular plant biodiversity for the sustainable livelihood security of the research area. (C) ETHNOMEDICINAL STUDIES Malam Jabba is a lush green valley strewn with an amazing variety of plants which supports spectacular medicinal plant biodiversity of promising economic values. A detailed study was carried out from 2013 to 2017 in order to elucidate ethnomedicinal and conservation values of medicinal plant biodiversity for the sustainable livelihood security of the Malam Jabba Valley, Hindu Kush Range, Swat, Pakistan. A total of 476 plant species have been documented and explored from the area. Local people were found to use 188 species belonging to 146 genera and 83 families for treatment of human and livestock ailments. Fifty five diseases/health groups of human and twenty four of livestock were recorded during the course of study being cured with ethno-medicinal and ethno-veterinary plants. Pteridaceae with 4 species and one genus was the leading family in Pteridophytes. In Gymnosperms, Pinaceae was largest family in term of species diversity having 6 species under 4 genera. In monocots, the largest number of species was contributed by Alliaceae with 3 species and single genus. The most important and leading families in term of species diversity in dicots were Lamiaceae and Rosaceae with (12 species each), Asteraceae (11 species), Solanaceae (8 species each), Cucurbitaceae and Euphorbiaceae (6 species each), Polygonaceae and Ranunculaceae (5 species each), Brassicaceae, Moraceae and Rhamnaceae (4 species each) while the rest of families had species with range of 1-3. Leaves (31%) were the most frequently used plant parts in the preparation of ethno medicinal recipes for the health care diseases followed by fruit (19%), whole plant (10%), roots (09%), seeds (09%), flower (05%), fronds (04%), shoots (04%), Bark (03%), rhizome (02%), bulbs (02%), latex (01) and resins (01%). The crude drug and folk recipes are mostly prepared in the form of decoctions, paste and powder drug. Mostly a single medicinal plant species was used and taken orally. Study also revealed that some plants have multiple medicinal values where as others were used for only one disease. IUCN Red List Categories and Criteria (2001,2012b) Version 3.1, Appendix Vll, following Guidelines for Application of IUCN Red List Criteria at Regional and National Levels (IUCN 2003 Version 3.0 & 2012a Version 4.0) were used for detailed investigation of conservation issues. Of the 188 species, 30 species were recorded Critically Endangered (CR), 30 species Endangered (EN), 27 species Vulnerable (VU), 35 species Near Threatened (NT), 41species Least Concern (LC), 04 species Data Deficient (DD) and 21 species Cultivated /Alien. The Valley is highly rich spot of medicinal plant biodiversity and local community utilized plant sources for their livelihood security but unsustainable harvesting of plant resources has threaten a significant portion of wild species in the area, resulting in a major decline in plant biodiversity and associated indigenous knowledge that support sustainable livelihoods, nutrition, local food security, medicine and health care. Most of the medicinal plant biodiversity are severely threatened in the area due to habitat loss, habitat degradation, deforestation, overgrazing, overharvesting of threatened, rare, endemic medicinal plants for various ailments, over exploitation of plant species for timber, fuel wood collection, ecotourism, population explosion, construction activities, introduction of invasive species and other environmental related disaster and hazards. Some globally important and endangered medicinal plants of the area are Berberis lycium, Colchicum luteum, Bistorta amplexicaulis, Podopyllum emodi, Juglans regia, Paeonia emodi, Polygonatum verticillatum, Primula denticulata, Geranium wallichianum, Rheum australe, Saussurea lappa, Skimmia laureola, Valeriana jatamansi, Viola betonicifolia, Viola canescens, Viola pilosa, etc. Non-sustainable and over harvesting of these medicinal plants faces a great threat to the flora of the Malam Jabba Valley. It may face a local extinction in near future if constantly being exploited at such commercial rate. Conservation measures are needed on urgent basis to protect threatened and critically endangered medicinal plant biodiversity from extinction in near future. It was recommended that public awareness about importance of wild medicinal flora, conservation practices, sustainable harvesting, utilization and cultivation of highly rich medicinal plant species is strongly desirable for sustainable livelihood security of the area. It was also recommended to protect rare, threaten and globally important plants by involvement of local community in their native habitats and identify factors affecting indigenous knowledge of medicinal plant biodiversity in the area." xml:lang="en_US