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New Results Regarding the Motion of Newtonian and Non-Newtonian Fluids Due to a Shear Stress on the Boundary

Thesis Info

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External Link

Author

Rana, Mehwish

Supervisor

Constantin Fetecau

Program

PhD

Institute

Government College University

City

Lahore

Province

Punjab

Country

Pakistan

Thesis Completing Year

2012

Thesis Completion Status

Completed

Subject

Mathemaics

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/2255/1/2501S.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726753716

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The present PhD dissertation has completed research on results related to flow behavior due to shear stress on the boundary of some Newtonian and non- Newtonian fluids under different circumstances. Firstly, we have discussed some concepts related to Newtonian and non-Newtonian fluids, constitutive equations, equations of motion and integral transforms. Secondly, we have presented the exact solutions of velocity, temperature and shear stress fields corresponding to some flows of Newtonian, second grade, Maxwell and Oldroyd-B fluids. We have established general solutions for the unsteady free convection flow of an incompressible viscous fluid due to an infinite vertical plate that applies a shear stress f (t) to the fluid, when thermal radiation and porous effects are considered. These general solutions may generate a large class of exact solutions corresponding to different motions with technical relevance. Some special cases are investigated under the effects of pertinent parameters on the fluid motion. Unsteady motion of second grade fluids induced by an infinite plate that applies a time-dependent shear stress f (t) to the fluid is also studied. General solutions may be reduced to new solutions of Newtonian fluids or they may be used to obtain known solutions from the literature. Furthermore, in view of an important remark, general solutions for the flow due to a moving plate may be developed. We have also studied the Couette flows of a Maxwell fluid caused by the bottom plate applying shear stress on the fluid. Exact expressions for velocity and shear stress corresponding to the fluid motion are determined using the Laplace transform. Two particular cases with constant shear stress on the bottom plate or sinusoidal oscillations of the wall shear stress are further discussed. Some important charac- teristics of fluid motion are highlighted through graphs. The unsteady motion of an Oldroyd-B fluid over an infinite flat plate is studied by means of the Laplace and Fourier transforms. After time t = 0, the plate applies cosine/sine oscillating shear stress to the fluid. The solutions obtained are presented viii as a sum of steady-state and transient solutions, which may easily be reduced to the similar solutions corresponding to Newtonian or Maxwell fluids. A central issue namely, obtaining the time for which the steady-state is reached is address by means of numerical calculations and graphical illustrations. The influence of oscillations frequency or of material parameters on this time corresponding to the steady-state is also analyzed. It is lower for cosine oscillations in comparison to sine oscillations of the shear, decreases with respect to ω and λ and increases with regard to λr .
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ڈاکٹر عبدالجلیل فریدی

ڈاکٹر عبدالجلیل فریدی
افسوس ہے گذشتہ ماہ ڈاکٹر عبدالجلیل فریدی اکسٹھ برس کی عمر میں ہم سے جُدا ہوگئے۔ مرحوم ایک نہایت بلند مرتبہ اور ماہرِ فن ڈاکٹر کی حیثیت سے ریاست میں ہرجگہ معروف اور مشہور تھے ، لیکن عملی سیاسیات کے میدان میں گامزن ہوئے ابھی انھیں دس بارہ برس ہی ہوئے تھے،اس کے باوجود وہ اس شان اور کروفرکے ساتھ اپنی ریاست کے آسمان ِ سیاست پر نمودار ہوئے کہ پرانے چراغ جھلملا کے رہ گئے۔ ان کی سیاست اگر چہ اتر پردیش تک محدود رہی،لیکن ان کی غیر معمولی شخصیت کاوقار اوروزن پورے ملک کے مسلمانوں میں ہر جگہ محسوس کیا جاتا تھا۔اس کی وجہ یہ ہے کہ مرحوم جذبہ اورعمل دونوں کے انسان تھے، نہایت جری،بے باک اورصاف گوتھے۔ان کی سیاست شترگربگی یامنافقت کے عیب سے پاک وصاف تھی۔اورسب سے بڑھ کریہ کہ سیاست کوجلب منفعت کا ذریعہ بنانے کے بجائے انھوں نے چند در چند مالی نقصانات برداشت کیے اور اپنی کمائی کے لاکھوں روپئے اپنے کازپر بے دریغ خرچ کرڈالے۔اخلاق وعادات کے اعتبارسے بھی وہ بڑی خوبیوں کے مالک تھے ۔عقیدہ اورعمل میں پکے اورسچے مسلمان، ہمدرد ومتواضع، خوش اخلاق وخوش طبع تھے، اس بنا پر مخالفین بھی ان کاادب واحترام کرتے تھے۔ عارضۂ صدر میں مبتلاتھے، روس اور یورپ میں اعلیٰ سے اعلیٰ علاج کرایا مگرمرض نہ گیا۔ایک مرتبہ بڑی حسرت سے بولے : میں نے ڈاکٹر کی حیثیت میں تین لاکھ مریضوں کے ہاتھ دیکھے ہیں،لیکن آج خود اپنا ہاتھ دیکھتا ہوں توحسرت ہوتی ہے ۔آخر یہی مرض جان لیوا ثابت ہوا اوروہ خدا کو پیارے ہوگئے۔ا للّٰھمَّ اغفرلہ وارحمہ۔ [جون ۱۹۷۴ء]

 

COMPARISON OF THE LEVEL OF BURNOUT AMONG THE ACADEMIC AND CLINICAL PHYSICAL THERAPISTS

Aims of Study: To compare the level of burnout among the academic and clinical physical therapists. Methodology: A cross sectional study was conducted from August 2019 to January 2020. Data was collected from physical therapists working in the universities and hospitals of Rawalpindi and Islamabad. Data was collected from 278 participants. Maslach burnout inventory scale was used to measure the level of burnout which was analyzed using SPSS statistics 21.  Results: The mean value of emotional exhaustion for clinical physical therapists was 20.02 ± 8.08 and for academic physical therapist was 18.6 ± 6.57 with significant p value (p˂0.05). The mean value for depersonalization for clinical physical therapists was 9.22 ± 5.17 and for academic 9.29 ± 5.07 with significant p value (p˂0.05). The mean value of personal accomplishment for clinical physical therapists and academic physical therapists was 35.43 ± 7.715 and 35.74 ± 6.49 respectively with non-significant p value (p˃0.05). Limitations and Future Implications: It was conducted for specific time period which not record the overall or yearly impact of burnout on participants. So time lapse and longitudinal study should be done. Originality: The clinical physical therapists have increased level of burnout than academic physical therapists. Conclusion: The clinical physical therapists have increased level of burnout than academic physical therapists.

Prevalence and Characterization of Fungal Pathogens Associated With Loquat Eriobotrya Japonica in Punjab Pakistan

In Pakistan, loquat (Eriobotrya japonica) is becoming a major fruit crop for local and export markets but its yield is continuously declining. The aims of the current study were to determine the geographical distribution, incidence and morpho-molecular identification of major fungal pathogens associated with loquat in Punjab, Pakistan. For this purpose, a total number of 34 loquat orchards were surveyed during summer and winter 2014 and summer and winter 2015 in loquat growing areas of Punjab. A total number of 2720 samples (fruit, leaves and twigs) were collected from Taxila, Wah Cantt, Khanpur, Tret, Chatar, Murree, Kalar Kahar and Choa Saiden Shah. Alternaria leaf spots and fruit rot, twig dieback, anthracnose, Curvularia leaf spot and fruit rot and Fusarium fruit rot were recorded in all locations. Fungal diseases were found in all orchards and average incidence was recorded as 25.55 percent and 27.6 percent of tree in two consecutive years. The environmental conditions for the development of fungal diseases were more favorable in summer as compared to winter and due to this, the disease incidences recorded higher in summer. During the second year, increases in fungal diseases incidence were recorded in Taxila (6 percent), Wah Cantt (5.5 percent), Khanpur (1.7 percent), Tret (1.65 percent), Choa Saiden Shah (1 percent), Chatar (0.85 percent) and Murree (0.65 percent), due to dispersal of infected loquat debris in loquat orchards. A reduction in disease incidence was observed in Kalar Kahar (1 percent) due to the proper sanitation measures. Alternaria alternata, A. mali, Curvularia lunata, C. geniculata, Colletotrichum gloeosporioides, C. capsici, Fusarium solani and F. equiseti were isolated from the infected loquat fruit and leaves while only Lasiodiplodia theobromae was observed to cause twig dieback of xvii loquat. A total number of 843 isolates were confirmed through morphological characterizations. Alternaria sp. was exhibiting the maximum (168) isolates followed by L. theobromae (146), Colletotrichum capsici (140), Fusarium sp. (136), C. gloeosporioides (131) and Curvularia sp. (122) and Alternaria leaf spot and fruit rot was prominent in Tret (26.54 percent), Khanpur (26.19 percent), Taxila (25.76 percent) and Wah Cantt (19.23 percent) while maximum incidence of Curvularia leaf spot and fruit rot, Fusarium fruit rot, twig dieback and anthracnose (C. capsici) was recorded in Chatar (20.59 percent), Murree (20.58 percent), Choa Saiden Shah (20 percent) and Kalar Kahar (17.86 percent) respectively. The pathogenic abilities of each isolate were checked on healthy loquat plants, detached leaves and fruit. The internal transcribed spacer regions (ITS1, 5.8S and ITS2) of 44 highly virulent fungal isolates was amplified through PCR assay and sequencing analysis of ITS regions exhibited 99 to 100 percent genetic homology with previously reported isolates. Five multi-genes sequence analysis viz ITS, translocation elongation factor 1-α (EF), beta-tubulin (BT), actin (ACT) and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) confirmed these pathogens at species level. The morphological characterization and multigene sequence analysis confirmed Lasiodiplodia theobromae, Curvularia lunata, C. geniculata, Colletotrichum gloeosporioides, C. capsici, Alternaria mali, A. Alternata, Fusarium solani and F. equiseti. The geographical distributions, incidences and morpho-molecular identification of major fungal pathogens is providing the guidelines for new researcher working on disastrous pathogens of loquat in Punjab Pakistan and this information will act as a remedy for development strategies of proper management of these destructive fungal pathogens.