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Theoretical Analysis of Dynamic Behaviors in Liquid Chromatography

Thesis Info

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Author

Javeria Nawaz Abbasi

Program

PhD

Institute

COMSATS University Islamabad

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2015

Thesis Completion Status

Completed

Subject

Mathemaics

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/786

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676727600616

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Theoretical Analysis of Dynamic Behaviors in Liquid Chromatography The chromatographic techniques are used on laboratory and industrial scales for the sepa- ration of substances that under the traditional processes, such as distillation or extraction, are neither technically nor economically feasible. It is an important separation technique in the petrochemical industry and becomes more and more exploited in fine chemical, phar- maceutical and biotechnical industries. For instance, this attractive technology is used to separate chiral molecules, enzymes, sugar and to purify proteins or to produce insulin. This thesis project is concerned with the analytical and numerical solutions of three stan- dard liquid chromatographic models namely, the equilibrium dispersive model (EDM), the lumped kinetic model (LKM) and the general rate model (GRM). Each model consid- ers different levels of complexities to describe the process. These models are systems of convection-diffusion partial differential equations with dominating convective terms and coupled through differential or algebraic equations. The Laplace transformation is applied to derive the analytical solutions of the EDM and LKM considering the special case of single-component linear adsorption isotherm, contin- uous or finite width pulse injections, two different sets of boundary conditions and fully porous particles. For further analysis of the solute transport behavior, the analytical tem- poral moments are derived from the Laplace-transformed solutions and are compared with the numerical solutions of a semi-discrete high resolution finite volume scheme (HR-FVS). For nonlinear adsorption isotherms, numerical techniques are the only tools to provide solu- tions. However, the strong nonlinearities of realistic thermodynamic functions pose major difficulties for the numerical schemes. For that reason, computational efficiency and accu- racy of the numerical methods are highly important. The suggested HR-FVS is extended to approximate these nonlinear model equations. The numerical results of the suggested HR-FVS are compared with some other finite volume schemes available in the literature. Different case studies are considered covering a wide range of mass transfer kinetics. The results obtained verified the correctness of analytical results and accuracy of the suggested HR-FVS. An interesting aspect of this thesis project is the application of GRM to fixed-bed chro- matographic columns packed with core-shell or fully porous particles. Due to their proven performance and improved availability, core-shell particles are increasingly applied for chro- matographic separations. Such particles are useful for highly efficient and fast separation of complex samples with a reasonably low back pressure. Cored beads provide advantages over fully porous beads, such as reduced diffusional mass transfer resistances in particle macropores and separation times. The concept has improved column efficiency by shorten- ing the diffusion path that molecules have to travel and thus, has improved the diffusional mass transfer kinetics in particle macropores. Once again, both single-component linear and multi-component nonlinear GRM models are considered. The above mentioned ana- lytical and numerical solution techniques are applied to solve the model equations. The potential of the solutions is demonstrated by considering different case studies that quan- tify the effects of the relative core size, axial dispersion, film mass transfer resistance and intraparticle diffusion resistance in the porous layer on the elution curves.
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اردو زبان کا آغاز و ارتقا

موضوع 10:اردو زبان کا آغاز و ارتقا
کسی زبان کے آغاز اور ارتقاء کی داستان کچھ مخصوص تہذیبی اور معاشرتی حالات سے جڑی ہوتی ہے۔ زبان اپنی ترقی یافتہ شکل اختیار کرنے سے پہلے مختلف مراحل سے گزرتی ہے۔ اسے رنگ و روپ دینے اور نکھارنے میں مختلف عوامل کار فرما ہوتے ہیں۔ اردو زبان جو آج کی چند ترقی یافتہ اور کثرت سے بولی جانے والی زبانوں میں سے ایک ہے اسے بھی معرض وجود میں آنے سے قبل مختلف مراحل سے گزرنا پڑا۔ ان مختلف مراحل اور تہذیبی اور معاشرتی عوامل کو سمجھنے کے لئے ہمیں ماضی کی طرف پلٹنا ضروری ہے۔
جیسا کہ تاریخ کے مطالعے سے پتہ چلتا ہے کہ ہندوستان کے قدیم باشندے دراوڑ تھے۔آریا قوم باہر سے آئی اور مقامی باشندوں کو پیچھے دھکیل کر ملک پر قابض ہو گئی۔آریا قوم ملک پر ایک نئی تہذیبی طاقت بن کر ابھری۔ ان کی زبان کو مرکزی حیثیت حاصل ہوئی۔ مقامی باشندوں سے میل جول کی وجہ سے آریاؤں کی زبان متاثر ہونے لگی اور بہت سے الفاظ کا تلفظ کچھ سے کچھ ہو گیا۔ آریاؤں نے اپنی زبان کو محفوظ رکھنے کے خیال سے اسے قواعدی اصولوں سے جکڑ دیا اور اپنی زبان میں صرف ٹکسالی الفاظ باقی رکھے۔مقامی اثرات اس سے پاک و صاف ہو کر ان کی زبان نے اپنا ایک معیار برقرار رکھا اور اسی معیاری زبان کو سنسکرت کا نام دیا گیا۔
اس زبان کو کافی فروغ حاصل ہوا لیکن اس کا رشتہ عوام سے کٹ گیا گیا اور ایک مخصوص دائرے تک سمٹ کر رہ گئی۔ عوام کی زبان مختلف علاقوں میں تھوڑے سے فرق کے ساتھ ایک رسم الخط میں موجود رہیں اس زبان کو پراکرت کا نام دیا گیا۔ پراکرت زبان برابر ترقی کرتی رہی اور مختلف علاقوں میں مختلف روپ اختیار کرتی رہی۔ آگے...

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