Sharif Digital Repository

Targeted delivery by either passive or active targeting of therapeutics to the bone is an attractive treatment for various bone related diseases such as osteoporosis, osteosarcoma, multiple myeloma, and metastatic bone tumors. Engineering novel drug delivery carriers can increase therapeutic efficacy and minimize the risk of side effects. Developmnet of nanocarrier delivery systems is an interesting field of ongoing studies with opportunities to provide more effective therapies. In addition, preclinical nanomedicine research can open new opportunities for preclinical bone-targeted drug delivery; nevertheless, further research is needed to progress these therapies towards clinical... 

2,4-Dinitrophenylhydrazones were efficiently and rapidly converted to their corresponding carbonyl compounds with supported potassium ferrate(VI) under microwave irradiation  

This paper presents a theoretical framework for the energy and exergy evaluation of a basic as well as three modified Organic Rankine Cycles (ORCs). The modified ORCs considered incorporating turbine bleeding, regeneration and both of them. The results demonstrate that evaporator has major contribution in the exergy destruction which is improved by increase in its pressure. The results confirm that the integrated ORC with turbine bleeding and regeneration has the highest thermal and exergy efficiencies (22.8% and 35.5%) and the lowest exergy loss (42.2 kW) due to decrease in cold utility demand and high power generation  

The ecotourism industry is one of the largest industries and has an important role in the economic social and cultural development of societies, especially in developing countries. Policymaking and planning procedures in this industry require the application of the methods that can appropriately model mutual and complex interactions and contacts. System dynamics is an accurate modeling method to simulate complex systems in a structured way and to design more effective policies by using these complex systems. In this study, the interactions and dynamics of the main components of ecotourism (effective variables) in the Taleghan area are modeled using system dynamics. To formulate and model... 

Controlling topographic features at all length scales is of great importance for the interaction of cells with tissue regenerative materials. We utilized an indirect three-dimensional printing method to fabricate polymeric scaffolds with pre-defined and controlled external and internal architecture that had an interconnected structure with macro- (400-500 μm) and micro- (∼25 μm) porosity. Polycaprolactone (PCL) was used as model system to study the kinetics of tissue growth within porous scaffolds. The surface of the scaffolds was decorated with TiO2 and bioactive glass (BG) nanoparticles to the better match to nanoarchitecture of extracellular matrix (ECM). Micrometric BG particles were... 

To investigate the gas–solid flow pattern of a combustor-style fluid catalytic cracking regenerator, a laboratory-scale regenerator was designed. In scaling down from an actual regenerator, large-diameter hydrodynamic effects were taken into consideration. These considerations are the novelties of the present study. Applying the Eulerian–Eulerian approach, a three-dimensional computational fluid dynamics (CFD) model of the regenerator was developed. Using this model, various aspects of the hydrodynamic behavior that are potentially effective in catalyst regeneration were investigated. The CFD simulation results show that at various sections the gas–solid flow patterns exhibit different... 

The three-dimensional (3D) nano scaffold of the cellulose acetate (CA) containing graphene/cobalt nanocomposite (0.1wt.%) was fabricated via electrospinning technique, and its impact on bone regeneration was investigated. Through this aim, bone marrow mesenchymal stem cells are cultured on the CA, and graphene/cobalt (rGO/Co)/CA nanocomposite scaffold surfaces and the samples are treated under low frequency alternative magnetic field (75Hz). The scaffolds are characterized using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and thermal studies (TG/DSC). The proliferation behavior of stem cells on CA, and rGO/Co/CA nano scaffolds are studied by MTT assay, show their... 

Many potential therapies are currently being studied that may promote neural regeneration and guide regenerating axons to form correct connections following injury. It has been shown that adult neurons have some limited regenerative capabilities, and the lack of connection formation between neurons is not an intrinsic inability of these cells to form axons after being damaged, but rather the inhibitory microenvironment of the injured tissue prevents regeneration. In this study, the polarization and chemotaxis of neuronal stem cells (NSC) in response to quantified gradients of nerve growth factor (NGF) was examined. To accomplish this, a microfluidic device was designed and fabricated to... 

Chatter vibration is a major obstacle in achieving high performance machining. In order to present a realistic model of chatter vibration, in this research, a finite element simulation of orthogonal chip formation combined with a 2D model of machine tool dynamics is developed. The proposed approach has the ability to incorporate various, mostly nonlinear, phenomena affecting chatter occurrence. The dynamic allows the tool to vibrate as a result of chip load variation leading to chatter. The 2DOF model makes it possible to observe the occurrence of model coupling phenomenon, in addition to the regeneration of waviness mechanism. The investigation of mode-coupling and regeneration phenomena in... 

A new reactor technology is used for propane dehydrogenation over a Cr 2O 3/Al 2O 3 catalyst. This reactor allows the continuous regeneration of the catalyst, but avoids the transfer of large amounts of solid between two reactors. Good similarity between experimental work and the model is realized. This is an abstract of a paper presented at the 18th International Congress of Chemical and Process Engineering (Prague, Czech Republic 8/24-28/2008)  

HVAC systems that use heat-regenerated desiccant wheels to remove moisture can be energy-efficient alternatives to traditional systems. Site-specific conditions and differing application requirements must be understood and quantified before desiccant-assisted hybrid systems can be justified on economic grounds. Although a detailed analysis is generally required, a few key variables drive costs and benefits. When two or more of these key variables favor a hybrid system over a conventional system, then a detailed analysis of the benefits vs. costs of a hybrid desiccant system is appropriate  

This article presents a new optimization algorithm based on integrating the use of genetic algorithms and tabu search methods to optimal allocation of dispersed generation resources in distribution networks. The proposed algorithm finds how much distribution losses can be reduced if dispersed generations are optimally allocated at the demand side of power system. A significant improvement of the proposed algorithm results, over that obtained by genetic algorithm, has been achieved. Numerical examples also showed the superiority of the proposed algorithm compared with the simple genetic algorithm. Copyright © Taylor & Francis Inc  

Due to the wide usage of rotary equipment and the necessity of their testing for maintenance and repair, test rigs have become necessary. The mechanical closed-loop test rig developed in Sharif University of Technology branch of ACECR (Academic Centre of Education, Culture and Research) is a test rig with low energy losses that is suitable for testing high power gearboxes such as aerospace or wind turbine gearboxes. It can be loaded up to 489Hp at a maximum speed of 3000 rpm, and the test components can be tested in different testing conditions including a variety of torques and speeds. This paper describes the preliminary, conceptual, and detailed design, steps including frame work design,...