Sharif Digital Repository

A sustainable supply chain requires constant sustainable changes in the design and performance of its steps. The main characteristic of sustainability is the consideration of social, environmental and economic criteria in strategic and operational decisions. Due to the great importance of the sustainability in transportation network, proper planning and careful design for this issue in recent years has been considered and welcomed by relevant researchers. In this research we want to provide an integrated frame work for transportation network design toward sustainability. In this regard, we also use 3D printing technology as our innovation in operations. Our main issue is the Inventory... 

Creating sustainable development in today's society is essential, and one of the most important elements to achieve this is the phenomenon of recycling. Lead-acid batteries are one of the sources of environmental pollution, and their separators contain 50% recyclable silica nanoparticles. In this research, impurities in these separators were removed using two methods: washing with water and sandblasting. The purity of recycled nanoparticles was 85.5% in the first method and 98% in the second method. In addition to the importance of recycling, finding a suitable use for recycled materials is also critical. FDM 3D printing is a new method of producing parts, but polypropylene is not commonly... 

In the last decade, mechanical metamaterials have attracted more attention due to new design principles that combine the concept of hierarchical architecture with material size effects at the micro or nano scale. This strategy shows extraordinary mechanical performance that we use in unknown parts of the material property space, including strength-to-density ratios, extraordinary flexibility, and the ability to absorb energy with brittle components. The aim of this research was to print metamaterial scaffolds from a combination of biocompatible and bioactive to be used as scaffolds in bone tissue engineering. In addition to the biological properties appropriate to the host tissue, the... 

In recent years, batch systems were often used in the synthesis of pharmaceuticals. Nowadays, due to the possibility of more optimal conditions in flow systems, such as better mixing and optimal performance of heat transfer and mass transfer, process safety, reduction of retention time, and ease in increasing the scale of the process, the use of flow systems has been expanded. B-hydroxysulfone is a pharmaceutical intermediate in the production of bicalutamide, which is used in the treatment of prostate cancer and is used in many organic and biological processes. The reaction time in batch systems is about 17 to 20 hours, and in the flow system, the retention time has reached about 180-90... 

Strain softening after the yield point is a prevalent phenomenon in the stress-strain response of cellular solids, consisting of porosities in micro/macro-meter scale, as well as polymers, consisting of free volumes in sub-nanometer molecular scale. Although the underlying micromechanisms for softening in cellular solids are already known, the molecular origin for softening in polymers is still unknown. In this thesis, the micromechanisms of the softening in both materials are investigated. Then, a hypothesis is raised and evaluated to connect the nano-mechanics of softening in polymers to the micro-mechanics of softening in cellular solids. Experiments of compression test, positron-based... 

Tissue engineering has the potential to revolutionize our health care system. Conceptually, lost or malfunctioning tissues will be replaced by man-made biological substitutes to restore, maintain, or improve function. Tissue engineering has already shown great promise to contribute to treatments of a myriad of diseases including osteoarthritis, cancer, diabetes, skin burns, cardiovascular conditions and various traumatic injuries. Tissue engineering is a highly multidisciplinary discipline that demands integration of knowledge, tools and skills from biology, chemistry, engineering and medicine. Integrating nano- and microtechnologies into clinically sized implants represents a major... 

The heart is a vital part of the body whose primary function is to pump blood throughout the body. The world's leading cause of deaths is due to heart problems. Today, most countries invest heavily in solving these problems and preventing the resulting deaths. One solution for patients with advanced heart disease is to use ventricular assist devices. This device is Used in parallel to the patient's heart, completely or partially replaces the normal functioning of the heart and provides much of the blood needed by the body. The purpose of this study is to design, manufacture and parametrically optimize a ventricular assist pump and its driver system. Since blood is clotted in contact with... 

Nowadays, storing solar renewable energy in hydrogen (as a clean fuel) is an attractive method for substitution of environmentally pollutant energy resources (fossil fuels) which is applicable through water splitting with the use of semiconductors. Among metal oxide photoanodes, WO3 as a moderate band gap semiconductor with high photo-stability, environmental compatibility, and low cost has attracted significant attention. However, photoelectron conversion efficiency of WO3 is still limited due to poor oxygen evolution reaction kinetics and charge carrier recombination. Herein, two strategies of nanostructuring and compositing with cocatalysts were applied to envisage with these limitations.... 

3D bioprinting technology is a promising approach for corneal stromal tissue regeneration. At first, two different concentrations of GelMA macromer (7.5% and 12.5%) were tested for corneal stroma bioprinting. Due to high macromer concentrations, 12.5% GelMA was stiffer than 7.5% GelMA, which made it easier to handle. In terms of water content and optical transmittance of the bioprinted scaffolds, we observed that scaffold with 12.5% GelMA concentration was closer to the native corneal stroma tissue. Subsequently, cell proliferation, gene and protein expression of human corneal stromal cells encapsulated in the bioprinted scaffolds were investigated. Cytocompatibility in 12.5% GelMA scaffolds... 

In recent years, additive manufacturing has been widely used in prototyping and production of industrial-commercial pieces. Additive manufacturing or three-dimensional (3D) printing is able to easily produce any piece for initial prototyping, no matter how complex it is. The fused deposition modeling (FDM) is a type of additive manufacturing process that produces the piece with the mechanism of feeding the PLA filament, then the molten polymer extrusion and depositing the fluid layer by layer with a high viscosity. Since the thickness of the layers is directly proportional to the diameter of the nozzle and the diameter of the used nozzles cannot be in the micron range (lower than 100... 

The processes of electrochemical water splitting and carbon dioxide reduction are among novel technologies that have gained attention for tackling climate change and global warming. Though, catalysts with fininancial justification for industrial utilization of these processes is still not available. In this study, a 3D-structured electrode of low-carbon 316 stainless steel, made by additive manufacturing, is modified with a trilayered metal-organic framework (MOF), with Iron, Cobalt, and Nickel metallic nodes and BDC-NH2 as the organic ligand, for water splitting. Also, the same steel electrode is modified with a single layered MOF, with Iron node and BDC-NH2 ligand, along with nanoparticles... 

In the last decade, the application of organ-on-chip systems to investigate the effectiveness and side effects of various drugs, modele diseases for different tissues has become noticed a lot because these systems are a promising approach to eliminate animal tests and clinical studies on different people. Current conventional methods for drug testing are expensive, time-consuming, and sometimes unreliable. Various organ-on-a-chip systems have been fabricated in order to mimic the conditions of different native tissues in the human body, but only the blood vessel has been considered in most of them while besides blood vessels, as a source to nourish cells, there are lymph vessels as a sink in... 

Manufacturing in many industries, such as electronics, petrochemical, automotive, and food, has long relied on continuous approaches, while the pharmaceutical industry has traditionally been processed in batch reactors. Since the beginning of the third millennium, continuous drug synthesis has received attention due to its multiple advantages over batch systems, which include process safety, adaptability, controllability, economic efficiency, scale-up, and enhancing performance. In this project, the pharmaceutical intermediate 1,4-benzodiazepine, which is usable as a precursor of diazepam and flurazepam, is continuously synthesized in a 400 microliters integrated micromixer and microreactor... 

Cranioplasty is a surgical procedure for repairing skull defects. This surgery will protect the brain tissue, reduce pain in the lesion site and reduce the psychological burden on the patient. Cranioplasty implants should have distinct characteristics, i.e., high strength for protecting the brain, full coverage of skull defects, resistance to infection, non-expansion with heat, and reasonable price. Titanium implants, bone allografts, hydroxyapatite, and methyl methacrylate are commonly used in this surgery. However, these materials have many disadvantages that limit their use. As a result, biodegradable material and 3D printing technology are the next steps for designing scaffolds according... 

In this research, a new method is proposed for constructing concrete structures with complex geometry, including topology-optimized concrete dams on a small scale. According to global statistics, concrete is the most consumed material in the world after water, and its production process causes a lot of damage to the environment. One of the best ways to reduce concrete consumption is to use tools such as topology optimization to design concrete structures. Nevertheless, few research has been done in the field of topology optimization of concrete dams, one of the important reasons for which is the difficulty of building physical model to perform physical tests, validating numerical models, and... 

Tissue engineering is a science that tries to create new tissues by using cells, growth factors and appropriate biological materials in order to repair damaged organs and replace parts lost due to various reasons. In this research, the effect of adding mxene sheets on the oxidized alginate-gelatin hydrogel scaffold was investigated. For this purpose, mxene nanosheets were first synthesized by Max phase chemical etching and its synthesis was confirmed by X-ray diffraction spectroscoy, field emission scanning electron microscope, X-ray energy diffraction spectroscopy, Fourier-transform infrared spectroscopy, UV-visible spectroscopy. Then, in order to prepare the scaffolds, different amounts of... 

Despite the increase in the number of cardiovascular diseases worldwide, the number of new drugs to treat these diseases has been decreasing in the last decade. Current preclinical drug evaluation strategies, which use cell cultures and oversimplified animal models, cannot meet the growing demand for new and effective drugs. In the last decade, the development of microfluidic bioreactors and organ-on-chip systems to improve the drug screening process has been increasing significantly. These systems have shown many advantages over previous preclinical models. Despite all these advantages, keeping the oxygen concentration at the optimal physiological level in microfluidic systems has its own... 

Polylactic acid (PLA) is considered as a great option to be employed as 3D porous scaffold in tissue engineering applications owing to its excellent biocompatibility and processability. However, relatively weak mechanical properties, low degradation rate and inappropriate biodegradability limit its extensive usage. In order to overcome the mentioned challenges, micrometric magnesium (Mg) particles were incorporated into the PLA matrix by the fused deposition modeling (FDM) technique. The effects of various Mg contents (i.e., 2, 4, 6, 8 and 10 wt%) on the mechanical, thermal, structural, wettability, rheological, biodegradability characteristics and cellular behavior of the 3D porous PLA-Mg...