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Computational Fluid Dynamics Modeling and Simulation of Hollow Fiber Membrane Contactors for Liquid-Liquid Extraction

Thesis Info

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External Link

Author

Muhammad, Amir

Program

PhD

Institute

University of Engineering and Technology

City

Peshawar

Province

KPK

Country

Pakistan

Thesis Completing Year

2017

Thesis Completion Status

Completed

Subject

Chemical Engineering

Language

English

Link

http://prr.hec.gov.pk/jspui/bitstream/123456789/11507/1/Amir%20muhammad%20chemical%20engg%202019%20uet%20peshawar%20prr.pdf

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676725778373

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Dispersion-free membrane-based Liquid-Liquid Extraction (LLE) is an emerging technique to recover a variety of solutes from aqueous streams. The process employs a Hollow Fiber Membrane Contactor (HFMC) that accomplishes the mass transfer between feed and solvent without any dispersion. Compactness of the unit, known and higher interfacial area, less solvent loss and independent control of operating flowrates are benefits of the process that make it attractive for researchers. Fluid dynamics and mass transport modeling of HFMC for dispersion free LLE process has been given the most attention in recent years. In the current study, numerical model has been developed to explore the dispersion free LLE processes. Extraction of copper (II) and aroma compounds from aqueous streams was taken as case study for the validation of the model.Copper (II) was extracted with trifluoro-acetylacetone (TFA) in commercially available HFMCs’ modules from LiquiCelTM (USA). A 2D model was developed for convection-diffusion mass and momentum transfer using continuity and Navier-Stokes equations. The model was simulated with Computational Fluid Dynamics (CFD) technique to study copper (II) extraction. The MatlabTM and COMSOL MultuphysicsTMsoftwares were used as simulation tools. The codes developed in MatlabTM were coupled with COMSOL MultiphysicsTM for recycled based dynamic system. Model was validated with experimental data and simulation was run to check effects of hydrodynamics conditions on contactor performance. Simulations were performed under various operating parameters and membrane geometrical characteristics in order to determine solute extraction efficiency, distribution profiles of copper (II) concentration, flux and velocity in 2-D. CFD model was then extended to investigate the extraction of four aroma compounds. These compounds have been recovered from aqueous solutions with hexane as an organic solvent in HFMC. Another model, which is based on resistance-in-series approach was also applied to study the extraction of copper (II). After validation with experimental results from the literature, the model was run to investigate the distribution of copper (II) at interface, transmembrane flux and height of transfer unit (HTU). The study revealed that an integrated mathematical model and numerical simulations can be effectively applied for the optimum design of membrane-based extraction processes.
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شفیق الرحمن قدوائی

شفیق الرحمن قدوائی
شفیق الرحمن مرحوم اگر چہ شہرت و ناموری کے عام معیار سے کو ئی بڑے آدمی نہ تھے مگر اپنے ایثار و قربانی، اخلاق وکردار، اخلاص و عمل اور خاموش اور بے لوث خدمات کے لحاظ سے بہت سے بڑے بڑے لیڈروں پر فائق تھے، جامعہ ملیہ کے لئے تو انھوں نے اپنی زندگی وقف کردی تھی اور سرد و گرم دور میں بھی اس سے جدا نہ ہو ئے، اور یہ کہنا غلط نہ ہوگا کہ جامعہ انہی کی محنت و جانفشانی کی بدولت زندہ رہ گیا، ظاہر وباطن دونوں میں مسلمان اور اپنے اوصاف کی بنا پر ہر جماعت میں مقبول تھے، کا نگریس اور حکومت دونوں کے سنجیدہ طبقہ میں ان کا بڑا وقار و وزن اور اخلاقی اثر تھا، مگر وہ اتنے بے لوث تھے کہ کبھی اس اثر سے فائدہ اٹھانے کی کوشش نہیں کی، ان کو بنیادی تعلیم کا عملی تجربہ تھا، اس کے وہ ماہر تھے، اس لئے یو این او کی جانب سے اس کام کے لئے انڈونیشیا بھیجے گئے تھے، ابھی وہ وہیں تھے کہ گذشتہ الیکشن میں کانگریس نے ان کو دہلی اسمبلی کے لئے مقرر ہو ئے، مگر اس سے بھی ان کا فائدہ اٹھانے کا موقع نہ مل سکا، تھوڑے ہی دنوں کے بعد بیمار پڑگئے، اور چند مہینے بیمار رہ کر ۳؍ اپریل کو انتقال کیا، انتقال کے وقت کل ۵۳ سال کی عمر تھی جو سیاست کی دنیا میں عین شباب کی عمرہے، مسلمانوں میں اب ایسے مخلص اور باعمل آدمی مشکل سے پیدا ہوں گے، اﷲ تعالیٰ اس پیکر اخلاص کو اپنی رحمت و مغفرت سے سرفراز فرمائے۔ (شاہ معین الدین ندوی، اپریل ۱۹۵۳ء)

 

شاذ: محدثىین اور احناف کى آراء کا تقابلى جائزہ

Veracity of trustworthiness of Hadith is an ongoing exercise of Islamic scholars to know whether the target hadith is safe and free from contradictions or not. It is mostly judged from its Sanad. Sometimes hadiths are ineffective. Besides this, a continuously referred hadith has also been considered as right. Conversely, a hadith is considered as impuissant (Daif) in certain conditions i.e. When it contradicts with Quran, famous Sunnah of Prophet Muhammad (PBUH), consensus (Ijma) of scholars of Ummah and in a particular exceptional (شاذ) case. In this article, a comparative analysis of views on irregular Hadith of Muhaddithin and Hanafi Jurists have been attempted. It discusses that how Jurists have considered and given a status to those irregular (شاذ) hadiths. And how do they differentiate those exceptional hadiths from mainstream hadiths?

Impact of Downsizing on Organizational Commitment, Motivation and Psychological Well-Being Among Workers of Secondary and Tertiary Organizations of Pakistan

Organizational downsizing becomes inevitable sometimes, for competence improvement, output augmentation or cost cutback but the results may be in the form of negative impacts on survivors’ thoughts, moral, and insights, if the technicalities of survivors’ psychological attitudes are not considered by the corporations. Its ultimate impact appears in the form of worsening organizational phenomena instead of improvement. Extent of downsizing is the main factor on which survivors’ potential psychosomatic thoughts and organizational behaviors are based. The present research uses experimental type-retrospective study design to explore the impact of downsizing and extent of downsizing, on survivors’ affective organizational commitment, work motivation and psychological well-being. Sixteen main and nine secondary hypotheses were formulated. A pre-formulated and pre- tested research questionnaire measuring affective organizational commitment, work motivation, psychological well-being, and downsizing was circulated. Disproportionate stratified random sampling technique was adopted to collect the data from 299 respondents before downsizing (72.93% response rate) and 520 respondents after downsizing (control group: 272 respondents with 71.58% response rate; and experimental group: 248 respondents with 62% response rate) from the four organizations throughout Pakistan; two from secondary and tertiary sectors of economy each. Data collected was examined employing explanatory statistics and ANOVA at 0.05 alpha levels. The results were further verified using Structural Equation Modeling (SEM) and Path Analysis techniques. As per results, a negative shift in survivors’ psychological attitudinal levels has been observed before and after downsizing. The downsizing itself, has negative effects on survivors’ organizational commitment, work motivation and psychological well- being and that psychological attitudes and behaviors are the limiting factors of extent of downsizing. As per results the extent of downsizing must be limited to a predetermined level (20% suggested by the study) to avoid the deteriorating effect on these psychological states. A positive correlation is found among the three attitudinal variables. Affective organizational commitment and psychological well- being have been found to be mediating the relationship between work motivation and some tangible demographics. The difference of experiences regarding xxv survivors’ attitudes is also assessed sector-wise as well as among organizations separately. This study provides a mean to academicians, researchers, and policy makers to understand the influence of downsizing and its extent on survivors’ selected attitudes in secondary and tertiary economy sectors of developing countries. Keywords: Downsizing, organizational commitment, work motivation, psychological well-being, secondary sector, tertiary sector, layoff survivors.