Sharif Digital Repository

Curcumin incorporated polyurethanes (CPU) are gaining much attention as a biomaterial. However, challenges are still remained due to hydrophobicity and low mechanical strength of CPU. Herein, we synthesized the CPU/ZnO nanocomposites with good mechanical and improved hydrophilic properties via in-situ polymerization. A series of curcumin incorporated polyurethane with different concentrations of ZnO nanoparticles (ZnCPU) are synthesized by using the curcumin, polyethylene glycol (PEG) as the soft segment, hexamethylene diisocyanate (HDI) as the hard segment, and 1,4-butanediol (BDO) as the chain extender. The addition of ZnO nanoparticles (NPs) facilitated the soft domain of PU which is... 

Stimulated devices are highly demanded for actuators and artificial muscles in the recent era but susceptible to low deformation at an applied voltage. In the present work, ionic liquids (ILs) based gel films were prepared from the polyvinyl chloride (PVC), dibutyl adipate (DBA), 1-butyl, 3-methimidazolium chloride, and 1-pentyl-3-methylimidazolium hexafluorophosphate by a simple solvent evaporation method. The structural, morphological, optical, and mechanical properties of the composite PVC/ILs gel were characterized by Fourier-transform infrared spectroscopy (FTIR), Large Angle X-ray scattering (LAXS), UV–visible (UV–vis) absorption spectroscopy, scanning electron micrpscopy (SEM) and... 

Stimulated devices are highly demanded for actuators and artificial muscles in the recent era but susceptible to low deformation at an applied voltage. In the present work, ionic liquids (ILs) based gel films were prepared from the polyvinyl chloride (PVC), dibutyl adipate (DBA), 1-butyl, 3-methimidazolium chloride, and 1-pentyl-3-methylimidazolium hexafluorophosphate by a simple solvent evaporation method. The structural, morphological, optical, and mechanical properties of the composite PVC/ILs gel were characterized by Fourier-transform infrared spectroscopy (FTIR), Large Angle X-ray scattering (LAXS), UV–visible (UV–vis) absorption spectroscopy, scanning electron micrpscopy (SEM) and... 

Nonlinear optical (NLO) materials are essential components in modern photonics and optical devices due to their ability to generate new frequencies through the nonlinear interaction with intense light. Synthesizing porphyrin-based NLO materials is complex and challenging, requiring specialized techniques to achieve high purity and yield. Controlling chromophore orientation and optimizing nonlinear optical properties are key difficulties that demand interdisciplinary efforts for practical photonics and optical applications. In the present study by using z-scan technique some of non-linear optical (NLO) parameters includingthird order NLO susceptibility (χ3), and molecular second... 

Ionic liquids, which are designable and nonvolatile, have become a hot topic in the field of CO2 separation from industrial gases. In order to utilize the nonvolatile and low heat capacity of ionic liquids, it is necessary to solve the problem of high viscosity of pure ionic liquids. In the present study, ether functionalized pyridinium ion [E1Py]+ with good biodegradability and low viscosity was selected as cation. Ions containing cyano groups were used as anions, such as thiocyanate ion [SCN]-, dicyanamide ion [N(CN)2]-, tricyanomethanide ion [C(CN)3]-. Three ionic liquids with low viscosity were synthesized and characterized by 1HNMR, 13CNMR and FTIR. The physiochemical properties of... 

Porphyrin-POM hybrid materials with excellent NLO properties are supposed to be a worthy entrant for forthcoming telecommunication, optical fibers, optical data storage and optical limiting devices, but due to adverse solubility problems, they are replaced by polymeric materials. Herein, we assessed third order NLO and second hyperpolarizability of porphyrin-polyimide compounds (NH-PI and Zn-PI) synthesized from the reaction of 4,4ʹ-hexafluoroisopropylidene-diphthalic anhydride (6FDA) with C44H32N6 (NH-DATPP) and C44H30N4Zn (Zn-DATPP) porphyrins under ambient conditions. The Z-scan measurement of these compounds revealed reverse saturation absorption as well as self-defocusing performance.... 

The dearth of efficient, robust, and economical electrocatalysts for water oxidation is dubiously the key obstacle for renewable energy devices, so synthesis of efficient, and cost-effective metal-based water oxidation catalysts is vital. Herein, Co3O4, Co9S8 catalysts and their heterostructure Co3O4/Co9S8 were synthesized and evaluated as water oxidation electrocatalysts. The characterization of Co3O4, Co9S8, and Co3O4/Co9S8 electrocatalysts was performed using Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction techniques. The heterostructure Co3O4/Co9S8 (1.46 V) exhibited water oxidation electrocatalysis at extremely low onset potential compared to... 

The dearth of efficient, robust, and economical electrocatalysts for water oxidation is dubiously the key obstacle for renewable energy devices, so synthesis of efficient, and cost-effective metal-based water oxidation catalysts is vital. Herein, Co3O4, Co9S8 catalysts and their heterostructure Co3O4/Co9S8 were synthesized and evaluated as water oxidation electrocatalysts. The characterization of Co3O4, Co9S8, and Co3O4/Co9S8 electrocatalysts was performed using Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray diffraction techniques. The heterostructure Co3O4/Co9S8 (1.46 V) exhibited water oxidation electrocatalysis at extremely low onset potential compared to... 

For more than a decade, stent implantation has been strategically used for solving gastrointestinal dilemmas such as biliary stenosis. Predicaments like insufficient radial strength, low twisting ability, inappropriate dynamic behaviour and restenosis are expected to be solved by the introduction of new designs. Superelastic Nitinol stent is an interesting alternative for minimising these tight spots. The application of finite element method to predict metallurgical and geometric behaviour of superelastic Nitinol stents for biliary duct dilatation is supported by conventional crimp tests. Model calculations show that all stents encounter the highest stress in their intersegment curvature.... 

Nitinol stents are used to minimize improper dynamic behavior, low twistability, and inadequate radial mechanical strength of femoral artery stents. In this study, finite element method is used to investigate the effect of crimping and Austenite finish temperature (A f) of Nitinol on mechanical performance of Z-shaped open-cell femoral stent under crimping conditions. Results show that low A f Nitinol has better mechanical and clinical performance due to small chronic outward force, large radial resistive force, and appropriate superelastic behavior  

Fully supramolecular dendrosomes (FSD) as bi-phase drug delivery systems are reported in this work. For preparation of FSD, amphiphilic linear-dendritic supramolecular systems (ALDSS) have been synthesized by host-guest interactions between hyperbranched polyglycerol having β-cyclodextrin core and bi-chain polycaprolactone (BPCL) with a fluorescine focal point. Self-assembly of ALDSS in aqueous solutions led to FSD. They were able to encapsulate paclitaxel with a high loading capacity. The dendrosome-based drug delivery systems were highly sensitive to pH and temperature. They were stable at 20-37. °C and pH7-8, but dissociated and released drug at temperatures lower than 20. °C or higher... 

Hybrid nanofluids exhibit higher thermal performance than conventional nanofluids. Due to improved thermal features of hybrid nanomaterials, these materials can be utilized in industrial and engineering devices to enhance their efficiency. Owing such applications, the aim objective of current study is to examine the behavior of radiative non-Newtonian Casson fluid submerged tiny particles of cobalt ferrite (CoFe2O4) and manganese zinc spinal ferrite (Mn − Zn Fe2O4). Behavior of flow is examined in a rotating porous cone with cluster interfacial layer impacts. Slip mechanisms of solid nanoparticles at the boundary of the surface are accounted. The governing flow model is acquired taking the... 

An energy management system (EMS) was proposed for a campus microgrid (μG) with the incorporation of renewable energy resources to reduce the operational expenses and costs. Many uncertainties have created problems for microgrids that limit the generation of photovoltaics, causing an upsurge in the energy market prices, where regulating the voltage or frequency is a challenging task among several microgrid systems, and in the present era, it is an extremely important research area. This type of difficulty may be mitigated in the distribution system by utilizing the optimal demand response (DR) planning strategy and a distributed generator (DG). The goal of this article was to present a... 

Considering the role of black hole singularity in quantum evolution, a resolution to the firewall paradox is presented. It is emphasized that if an observer has the singularity as a part of his spacetime, then the semi-classical evolution would be non-unitary as viewed by him. Specifically, a free-falling observer inside the black hole would have a Hilbert space with non-unitary evolution; a quantum jump for particles encountering the singularity to outside of the horizon as late Hawking radiations. The non-unitarity in the jump resembles the one in collapse of wave function, but preserves entanglements. Accordingly, we elaborate the first postulate of black hole complementarity: freely... 

Peer-to-peer (P2P) energy trading platform is an upcoming energy generation and effective energy managing strategy that rewards proactive customers (acting as prosumers) in which individuals trade energy for products and services. On the other hand, P2P trading is expected to give multiple benefits to the grid in minimizing the peak load demand, energy consumption costs, and eliminating network losses. However, installing P2P energy trading on a broader level in electrical-based networks presents a number of modeling problems in physical and virtual network layers. As a result, this article presents a thorough examination of P2P studies of energy trade literature. An overview is given with... 

Stent implantation has been regarded as a major strategy to solve gastrointestinal diseases such as biliary obstruction during the last decade. The application of nitinol superelastic stents has been recently considered for minimising such problems as restenosis after stent implantation, the ability to low stent twist, unsuitable dynamic behaviour and inadequate strength radial of stent. In the present article, the effects of material properties on mechanical performance of Z shaped nitinol wire stent under crushing test for clinical applications are studied by finite element modelling. Nitinol stent shows better mechanical and clinical performance after applying 90% crushing, less chronic... 

Effects of pH, D2EHPA, Cyanex® 272 and Cyanex® 302 on extraction of zinc, manganese and cobalt from a Zn-Mn-Co-Cd-Ni containing solution at the room temperature was comprehensively investigated. Addition of Cyanex® 302 indicated a left-shifting-effect on the extraction curve of zinc, a right-shifting-effect on the extraction curve of manganese and no effect on the extraction of cobalt. Addition of Cyanex® 272 shifted all three curves to the right. Therefore, the most suitable extractant for separation of zinc from manganese was therefore 0.3-0.3 mixture of D2EHPA and Cyanex® 302, and that for separation of manganese from cobalt was pure D2EHPA. The stoichiometric coefficient for the... 

Electrical energy is very necessary for human life in the modern era. The rising energy prices, depletion of fossil fuels, and instability of the grid are alarming situations. So, it needs a smart solution to ensure the balance between pricing and saving natural resources. Some other issues like environmental change, limitations on installation of new transmission lines, reliability concerns, and considering the expansion in distributed energy generation technologies promise the implementation of distributed generation extensively. The integration of two or more energy supplies in a power system is known as distributed energy resource system. In this study, a university campus is taken as a... 

Compound 3-benzyl-2H-pyrano[3,2-c]chromene-2,5(6H)-dione(3), was prepared and fully characterized. The vibrational modes (FT-IR) and NMR data ( 1H and 13C chemical shifts) were compared with the results of Density Functional Theory (DFT) method at the B3LYP/cc-PVTZ level. The calculated vibrational frequencies and NMR chemical shifts are in good agreement with the experimental results. The electronic (UV-Vis) spectrum was calculated using the TD-DFT method in CH2Cl2 with the Polarizable Continuum Model using the integral equation formalism variant (IEFPCM) and was correlated to the experimental spectra. The assignment and analysis of the frontier HOMO and LUMO orbitals indicate that... 

Various researchers have contributed to the identification of the mass and stiffness matrices of two dimensional (2-D) shear building structural models for a given set of vibratory frequencies. The suggested methods are based on the specific characteristics of the Jacobi matrices, i.e., symmetric, tri-diagonal and semi-positive definite matrices. However, in case of three dimensional (3-D) structural models, those methods are no longer applicable, since their stiffness matrices are not tri-diagonal. In this paper the inverse problem for a special class of vibratory structural systems, i.e., 3-D shear building models, is investigated. A practical algorithm is proposed for solving the inverse...