Sharif Digital Repository

In this research, Mg-Zn bulk metallic glasses have been investigated using molecular dynamics simulation. In order to study the structure of this alloy, coordination number, short and medium order of chemical range, Voronoi analysis, glass conversion temperature and atomic pair distribution function have been used. According to the results, the full icosahedral structure with IS connection type in comparison with other structures has an essential role in the stability of the system during cooling and creating medium-scale areas. The results show that the ability to form glass depends on the chemical composition and cooling rate. In this research, the cooling rate is considered to be 1011 K/s... 

Polyamide6 has many engineering applications due to its physical, mechanical and processability properties. However, its low impact resistance limits the use of polyamide6. One of the common ways to overcome this problem and extend the range of polyamide6 application is its elasticity with elastomeric materials, which reduces the strength and modulus (tensile and flexure) in comparision with neat polyamide6. To overcome this limitation, various reinforcements, often fiber or particle-shaped, are used. Today, with the development of nanoparticles, this effort is being made to use nanoparticles, especially carbon nanoparticles with unique properties. Recent research has shown that the addition... 

Drying is one of the important downstream processes in the production of biotechnological products. The dryer design for heat-sensitive materials such as proteins requires special process considerations. In this study, a rotary dryer evaluated for drying protein products. The used liquid enzyme as model, a bacterial α-amylase, first, immobilized on sodium sulfate and sodium tripolyphosphate as carriers in a spraying mode and then, the obtained wet solid materials containing the enzyme, dried in a batch dryer. The performance of this dryer investigated to achieve suitable properties such as the enzyme activity and the final moisture content of product by changing the process conditions.... 

In the world today, biological materials widely used are which requires proper packaging, the types of enzymes are used in various industries: food, pharmaceutical, cosmetics. Shelf Life of enzymes Limited and affected by internal and external factors a maximum of one year. Internal factors include water activity, pH, microbial flora, oxidation-reduction potential, chemistry and biochemistry products, product formulation, additives and the reaction with package. External factors such as relative humidity, light, gas atmosphere within the package, the storage conditions and temperature. Water activity and relative humidity are important factors in spoilage. Avoid drying, lipid reaction,... 

In biotechnology processes, in addition of culture media there is a solid phase which dispensed across the system.In most of bioprocesses, first operational unit for downstream treatment is the separation of this particles from fermentation liquor. In contrast with other categories like inorganic chemistry, solid particles in fermentation liquor (which the main part of it is biomass itself) have complicated physical & rheological properties. For example, all of biomass species are hydrophilic and sometimes form colloidal solutions.With this perspective, separation of solid phase from fermentation liquor is a hard challenge in this kind of processes.In this research, with regard of great... 

The outbreak of a type of corona virus in 2019, plunged the world into a huge panic. Businesses entered into an unprecedented recession and economic growth was severely reduced. Millions of people have been infected and unfortunately countless numbers have also lost their lives. This which quickly crossed the borders of countries, proved how much a not-so-deadly infectious disease can affect human life. Another point that was revealed was the importance of epidemiology knowledge. Since the beginning of the outbreak of this disease, scientists in this field have tried to predict the state of the disease in the coming days by presenting models. Many countries formed special working groups to... 

In this study, mixing of binary solids in Tapered beds with inlet jet using solid particle particle techniques was investigated. A two-dimensional model in which the motion of solid particles and gas in two dimensions is studied is used to simulate the conical beds. For the particle phase by solving the equations obtained with the gas phase equations simultaneously considering the equations and collisions between particles and the gas with the particle is simulated using DEM model. In this study, mixing of binary solids with two different sizes and the influence of simulation parameters such as inlet jet velocity, jet position, using multiple jets instead of single jet with same inlet flow,... 

Due to the successful experience gained in the process intensification and implementation of Reactive Distillation and Divided Wall Column in industry, Reactive Divided Wall Column have also been considered as a further step in process intensification. One important research area in implementation of RDWCs is their control issue. In the present study, the dynamic simulation of reactive divided wall columns and their control were studied and the adaptive model predictive control was used for the control objectives. Aspen Dynamics software was used for simulation and MATLAB software was utilized for applying the control strategy. The advantage of the applied control method is the use of...