Search or add a thesis

Advanced Search (Beta)
Home > Multidimensional Process Models for Seeded Batch Crystallization

Multidimensional Process Models for Seeded Batch Crystallization

Thesis Info

Access Option

External Link

Author

Noor, Saima

Supervisor

Habil. Shamsul Qamar

Program

PhD

Institute

COMSATS University Islamabad

City

Islamabad

Province

Islamabad.

Country

Pakistan

Thesis Completing Year

2011

Thesis Completion Status

Completed

Subject

Mathemaics

Language

English

Link

http://prr.hec.gov.pk/jspui/handle/123456789/1949

Added

2021-02-17 19:49:13

Modified

2024-03-24 20:25:49

ARI ID

1676726731895

Asian Research Index Whatsapp Chanel
Asian Research Index Whatsapp Chanel

Join our Whatsapp Channel to get regular updates.

Similar


This contribution focuses on the modeling and numerical approxima- tion of population balance models describing batch and polymorphic crystallization processes. Such processes have wide range applica- tions inne chemicals, pharmaceutical, minerals, and food indus- tries. Di erent numerical techniques are employed for solving these models in one and two property coordinates. The space-time CE/SE method and the semi-discrete upwindnite volume schemes are de- rived and implemented to solve the batch crystallization models with nes dissolution. Thene dissolution reduces undesirable small crys- tals and improves the quality of a product. A delay in the recycle pipe is also included in the model. Apart from the above mentioned methods, a new numerical technique is introduced to solve a model describing polymorphic crystallization of L-glutamic acid. The sug- gested technique employs together the method of characteristics and Duhamel''s principle to approximate the considered model e ciently and accurately. This technique has capability to produce accurate results on coarse meshes and no mesh re nement technique is needed for further improvement in the results. Furthermore, an alternative bivariate quadrature method of moments (QMOM) is developed for solving two-dimensional batch crystallization model involving crys- tals growth, nucleation, aggregation, and small nuclei dissolution in an external loop. The quadrature points and weights are obtained by using the orthogonal polynomials of lower order moments. Several case studies are carried out. The numerical computations demonstrate the eficiency, accuracy, and robustness of the proposed schemes. The results agree with the experimental predictions and could be used for process design and optimization.
Loading...
Loading...

Similar Books

Loading...

Similar Chapters

Loading...

Similar News

Loading...

Similar Articles

Loading...

Similar Article Headings

Loading...

پسلی

پسلی

ڈاکٹرمجاہد عباس

لیکچرار شعبہ اردو، نمل، اسلام آباد

’’پسلی‘‘ کا بستہ اندر باہر سے دوات    کی سیاہی کے سبب  اس کے دل کی طرح داغ دار تھا۔  پلاسٹک کی  ایک پرانی دوائیوں والی شیشی میں چند پرانی  لیریں ، چند قطرے  نلکے یا نالے کا پانی اور ایک سیاہ پڑیا  ڈال کر اس نے دوات بنانے کی ترکیب  اپنےہم جولیوں سے سیکھ لی تھی۔ شیشی کا ڈھکن ٹوٹا ہوا تھا جسے اس نے ایک لیر  کی مدد سے   مضبوطی سے باندھ رکھا  تھا مگر اکثر اوقات دوات کے سیاہ قطرے اس  کےقاعدے، تختی اور بستے  میں رچ بس جاتےتھے۔ اس کا قلم  کانے  کا تھا جس کی نوک پر دوات جم کر کسی پھوڑے کے کھرنڈ جیسی ہو چکی تھی۔ وہ  سکول کے احاطے میں  داخل ہونے سے پہلے ایک لمحے کے لیے رکتا اور پھر دانت بھینچتا ہوا آگے بڑھ جاتا۔ وہ جب  تختی پر  الف ب ج لکھتا تو اس سے ایک حرف بھی سیدھا نہ لکھا جاتا۔ لکھتے ہوئے وہ  اپنے ہاتھ کو اپنے ذہن کے تابع کرنے کی کوشش میں  یوں محو ہوجاتا کہ اسے خبر ہی نہیں رہتی تھی اور اس کے بدن کی تختی ٹیڑھی ہو جاتی ہے۔ استاد کی  آواز اسے چونکا دیتی اور وہ کچھ دیر کے لیے سیدھا ہو جاتا  اور اگلا حرف لکھتے ہوئے پھر اس کا سرڈھلک جاتا، آنکھیں  ترچھی دکھائی دیتیں اور وہ بہتی ناک کو الٹی آستین سے  اپنی ہی دھن میں  رگڑتا رہتا تھا۔

سکول سے گھر تک پہنچتے  ہوئے اسے کئی دشوار راستوں سے گزرنا پڑتا۔ایک ایک کر کے اس کے ہم مکتب راستے میں چھوٹتے جاتے اور وہ اکیلا رہ جاتا۔ویسے بھی وہ سب کے ساتھ گھلتا ملتا نہیں تھا کیونکہ اکثر لڑکے اس کی ...

Discourse on Madrassah Education Reform in Pakistan: Challenges to State Narrative and its Implications

It is generally perceived that Madrassah produce extremism which possesses a threat to the peace and security of the state and to the world as well. Government along with local and International community wants to eradicate extremism and terrorism through reforming Madrassah education. The purpose of current study is to answer the question “why attempts of Madrassah reforms were unfruitful”? By focusing on it, study is divided into three phase such as to find out; different narrative on Madrassah reform, potential barriers in the way of reform and skepticisms associated with reformist policy. The main objective of current study is to understand the problems regarding Madrassah reform through realistic approach by addressing main question what are the challenges in developing alternative narrative on Madrassah reforms and its implications? The main investigation has three driving questions that what Madrassah reform means in point of view of different actors? What are main obstacles in the process of reform? And what are skepticisms about reform? In this qualitative study stakeholder interviews have been conducted. Results of the study indicates that Government narrative with regards to Madrassah education reform is to bring them into mainstream whereas religious community think that there are hidden agendas behind the modernization of Madrassahs. They viewed Madrassahs reforms to dilute the attention of religious sector from religious education to western education. Similarly, it viewed that changes in curricula, financial control, regulatory change, and vested interest are the main hurdles in the way of reform.

Design and Development of a Continuous Solar Roaster Csr for the Processing of Agricultural Products

About 30% of perishable agriculture products are spoiled during post-harvest processing. This study has been taken up for the enhancement of existing post-harvest processing facilities using renewable energy by developing a continuous solar roaster (CSR) for the on-farm roasting of different agricultural products. Existing roasting techniques are not adoptable for the growers of developing countries due to high initial investment and rapidly escalating prices of non-renewable energy resources. A 10 m2 Scheffler reflector is used to generate thermal energy by converging the incoming direct normal irradiance (DNI) at a 460 mm diameter copper coil heat exchanger which is transferred to a 2000 mm long and 450 mm in diameter roasting cylinder by circulation of thermal oil. Hot thermal oil delivers the absorbed heat to products while flowing in a semi-circular oil jacket (13.5 liter capacity) installed beneath the roasting cylinder. Groundnuts were fed into the roasting cylinder through a 0.015 m3 capacity feeding hopper and slide towards discharge chute with the help of ribbon type paddle screw conveyor. Performance evaluation results showed that more energy can be drawn in winter season than the summer with standing Scheffler reflector in northern hemisphere and maximum cooking power was calculated to be 3279 W under the average DNI of 815 W/m2. Central composite rotatable design (CCRD) technique was selected to design the experiments in Design Expert® (Version: 11.0.5.0 64-bit) software to investigate the single and interactive effects of operating parameters of CSR. The optimization results for maximum feeding capacity (15 kg) and minimum thermal oil flow rate (0.01 L/s) revealed that the conveyor speeds of 1.42 rpm, 0.99 rpm and 0.69 rpm corresponding to 14+0.1, 20+0.1 and 29+0.1 min roasting time resulted in light, medium and dark quality groundnut roasting respectively. Final moisture contents of groundnut kernels were found to be 1.99, 1.73 and 1.34% against the L* value of 53.42, 48.77 and 43.41 at light, medium and dark roasting respectively. On a sunny day, 140 to 288 kg groundnuts can be continuously roasted subjected to light to dark roasting conditions respectively with satisfactory food quality. The payback period of CSR was assessed to be 1.7 to 3.9 years depending upon the alternate source used for equivalent energy generation. It was also estimated that CSR can generate about 55 MWh energy for roasting in expected life span of 10 year. For equivalent energy production, CO2 emission by wood, coal, diesel, kerosene and gas were found to be 21.45, 19.25, 14.85, 14.30 and 11 thousand tons respectively. The overall system efficiency was found to be 39 to 41%.