Sharif Digital Repository

A Zn-Rich (GaN)1−x(ZnO)xnanostructure was synthesized with the assistance of a high-gravity technique in order to reduce the reaction time and temperature. The synthesized inorganic nanomaterial has been applied in both drug and gene delivery systems, and as the first fully inorganic nanomaterial, it was investigated in a comprehensive cellular investigation as well. In order to increase the potential bioavailability, as well as the interactions with the pCRISPR, the nanomaterial was enriched with additional Zn ions. The nanomaterial and the final nanocarrier were characterized at each step before and after any biological analysisviaFESEM, AFM, TEM, FTIR and XRD. The polymer coated... 

The absorption characteristics of zirconium nitride (ZrN)-based metamaterial absorber of fractal geometry are studied. The proposed absorber is comprised of fractal metasurface at the top having subwavelength-sized periodic pattern of specially designed ZrN circular nano-discs arranged over silicon dioxide (SiO2) substrate. A tri-layer graphene, owing to its exhibiting better tunability, is introduced at the interface of metasurface and substrate. The bottom side of SiO2 is coated with silver nanolayer to block transmission. The absorptivity essentially depends on the kind of fractal design used in metasurface to configure the absorber. The obtained results exhibit the absorption... 

In this study, ternary MWCNTs/CoFe2O4/FeCo nanocomposite coated with conductive PEDOT-polyaniline (PA@MW/F/C) co-polymers were synthesized by microwave-assisted sol-gel followed in-situ polymerization methods. The phases, crystal structures, morphologies, magnetic and electromagnetic features of the as-prepared samples were identified via XRD, SEM, XPS, VSM, and VNA respectively. Absorption characteristics were investigated in the frequency (12–18 GHz) Ku band. XRD, VSM and SEM analysis confirmed the partial reduction process of CoFe2O4 and successfully decorated magneto-dielectric particles with co-polymers. By measuring electromagnetic features of the samples, it was found that coating... 

In terms of manufacturability, there is a high tendency to deposit light-absorbing CuInS2 films by solution processing methods like ink-based depositions. In particular, for nanoparticle inks, the synthesis of highly dispersed and stable inks, with uniformity in the deposition process, is a serious challenge. Here, we demonstrate a novel two-step low-temperature CuInS2 film deposition method in which the In2S3 is deposited first. It then partially is converted into CuInS2 through the infiltration of Cu+ ions in the In2S3 layer in a dip-coating process. The resulting films are highly uniform, with diffraction peaks indicating the formation of pure CuInS2 phase. The proper stoichiometry of... 

The design and development of efficient approaches for water–oil separation have had widespread interest. Most previously introduced techniques and materials used for development of the successful separation of oily wastewater could not answer all the desired demands, such as being efficient and environmentally and economically friendly. Therefore, in seeking a novel method capable of answering these expectations, surfaces with special wettability were introduced. A novel, reusable, and recyclable superhydrophilic and superoleophobic poly(Vsim-Vim)@PFOA@SiO2 nanocomposite-coated stainless steel mesh was synthesized through a facile preparation process. Since the most important factors of... 

Biocompatible nanostructured coating plays an important role in enhancement of osseointegration ability of metallic implants. This study sets out to obtain optimized SiC concentration in Hydroxyapatite (HA) coating on AISI 316L stainless steel alloy through electrophoretic deposition method. Effect of SiC concentrations (1, 2, and 3%.wt) on the morphology, corrosion behaviour, and mechanical properties of the HA coating is investigated. Results show that SiC could obstruct the formation and growth of micro cracks in the HA coating where HA-3%SiC is considered as a crack free coating. Electrochemical tests reveal that SiC has improved the corrosion resistance of HA coating, and HA-3%SiC... 

Utilizing 3D and 2D porous materials modified by a superhydrophobic/philic coating for quick removal of oil from water and a continuous process of oil/water separation, respectively, has attracted a lot of attention recently. Here we report the separation capacities of one commercial and three home-made sponges, sprayed by a superhydrophobic coating, for a broad range of oils and solvents. The contact angle of water on the coated sponges is 162.5˚, whereas the pristine sponge shows a contact angle of 91.8˚ (these values are for sponge D which had the highest absorption capacity). We investigate the effects of the density of sponges and the dynamic viscosity of oils and solvents on the... 

This paper analytically studies the effect of functionally graded materials (FGMs) on the primary resonances of large amplitude flexural vibration of in-extensional rotating shafts with nonlinear curvature as well as nonlinear inertia. The constituent material is assumed to vary along the radial direction according to a power-law gradation. The governing differential equations and the corresponding boundary conditions are derived employing the variational approach. Then, the Galerkin method and the multiple scales perturbation method are utilized to obtain the frequency–response equation. In a numerical case study, the effects of the power-law index on the steady-state responses and locus of... 

LiNi0.8Co0.1Mn0.1O2 (NCM811) has been considered as a promising cathode for Li-ion batteries (LIBs) due to its high electrochemical capacity and low cost; however, poor cycling stability is one of the main restricting factors in industrial applications of the NCM811 cathode material. Notably, the capacity fading and low structural stability of NCM811 are intensified at elevated temperatures. ZrO2- and composite rGO-ZrO2-coated NCM811 were fabricated by a facile wet chemical method and evaluated at 25 and 55 °C to overcome these impediments. The ZrO2 coating provides superior cycling and thermal stability and perfectly protects the cathode active material from deleterious side reactions, and... 

This work aims to present an experimentally verified analytical solution to examine damping properties of systems including viscoelastic treatments. Although there are several methods for characterizing the behavior of three-layer damping systems, the RKU method is the most frequently used one. In this paper, this method is modified such a way that to be applied for a five-layer damping system. The achieved analytical relations are then employed to study the effects of a four-layer vibration-absorbing coating on the dynamic behavior of an aluminum sheet with free-free boundary conditions. Since the vibration-damping properties of the coating are unknowns, its loss factor and shear modulus... 

In this research, the effect of surface characteristics on boiling heat transfer has been investigated experimentally. For this purpose, a device with the ability to automatically record the liquid temperature of the inlet and outlet of the test area, calculate the coefficient of boiling heat transfer, and heat flux has been developed. The automatic temperature stability of the working fluid and the ability to investigate the effect of surfaces with different characteristics (in terms of material and surface structure) on the boiling heat transfer parameters are the most important features of this device. The performance of the experimental setup was evaluated by the modified "Chen" equation... 

In this study, nano-sized diamond particles (ND) were functionalized in two consecutive stages. First, dry thermal oxidation was employed to obtain carboxylated ND. In the next step, carboxylated ND was properly surface modified through wet chemistry to acquire aminated-ND (ND-NH2). Then, polyaniline (PANI) was synthesized in the presence of aminated-ND particles at a broad concentration from 1 wt% to 70 wt% to obtain PANI/ND hybrid nanostructures. The chemical structure, morphology, and thermal stability of nanoparticles were comprehensively characterized by different techniques such as FT-IR, UV–visible, TGA, XRD, FESEM, and TEM. It was observed that the morphology of PANI/ND... 

Condensation heat transfer on stainless steel tube utilizing superhydrophobic coatings was investigated. The electrophoretic deposition and spraying methods were employed to coat the tubes’ outer surface. The mixture that was synthesized for spray coating was a hybrid paint. It incorporated polyurethane matrix and a colloidal suspension containing organic nanoparticles. The hybrid paint had a proper adhesion to the substrate which caused more durability compared to the electrophoretic coating. The agglomeration of nanoparticles in the hybrid paint caused the formation of particles with larger size compared to the particles in the electrophoretic coating. Consequently, contact angle... 

A one-pot and facile method with assistance of high gravity was applied for the synthesis of inorganic two-dimensional MOF-5 embedded MXene nanostructures. The innovative inorganic MXene/MOF-5 nanostructure was applied in co-delivery of drug and gene, and to increase its bioavailability and interaction with the pCRISPR, the nanomaterial was coated with alginate and chitosan. The polymer-coated nanosystems were fully characterized, and the sustained DOX delivery and comprehensive cytotoxicity studies were conducted on the HEK-293, PC12, HepG2, and HeLa cell lines, demonstrating acceptable and excellent cell viability at both very low (0.1 μg.mL-1) and high (10 μg·mL-1) concentrations. The... 

Herein, the NH2-UiO-66 metal organic framework (MOF) has been green synthesized with the assistance of high gravity to provide a suitable and safe platform for drug loading. The NH2-UiO-66 MOF was characterized using a field-emission scanning electron microscope, transmission electron microscope (TEM), X-ray diffraction, and zeta potential analysis. Doxorubicin was then encapsulated physically on the porosity of the green MOF. Two different stimulus polymers, p(HEMA) and p(NIPAM), were used as the coating agents of the MOFs. Doxorubicin was loaded onto the polymer-coated MOFs as well, and a drug payload of more than 51% was obtained, which is a record by itself. In the next step, pCRISPR was... 

Nowadays, increasing the CO2 emissions are one of the inevitable challenges in the world. In addition, in many industries, fossil fuels are the main source of energy demands which worsen the problem. Since in most applications, the performance and energy loss are highly affected by the drag force, many investigations have been proposed to improve the surface properties to moving surface against the water, and consequently, increasing drag reduction. To this end, one effective way is utilizing superhydrophobic coatings. In this study, we prepare two different superhydrophobic coatings using Al2O3 nanoparticles (NPs) modified by HMDS (1,1,1,3,3,3-Hexamethyldisilazane) and PDMS... 

Designing multifunctional surfaces is key to develop advanced materials for orthopedic applications. In this study, we design a double-layer coating, assembled onto the completely regular titania nanotubes (cRTNT) array. Benefiting from the biological and topological characteristics of chitosan nanofibers (CH) and reduced graphene oxide (RGO) through a unique assembly, the designed material features promoted osteoblast cell viability, prolonged antibiotic release profile, as well as inhibited bacterial biofilm formation. The synergistic effect of RGO and CH on the biological performance of the surface is investigatSed. The unique morphology of the nanofibers leads to the partial coverage of... 

In this study, for the first time, the influence of the nanoporous Zr-based NH2-UiO-66 metal-organic frameworks (MOFs) on the tensile strength and fracture toughness of the epoxy coating was investigated. In addition, the impacts of the UiO particles' functionality (i.e., NH2 or GMA) on the MOFs/epoxy interfacial bonding and nanoparticles dispersion quality in the epoxy resin were examined by the tensile test, dynamic mechanical thermal analysis (DMTA) and field emission-scanning electron microscope (FE-SEM). The NH2-UiO-66 and GMA-UiO-66 MOFs chemical structures were investigated by FT-IR, BET, and FE-SEM approaches. The FE-SEM investigation of the fracture morphology (at the cross-section... 

For the first time, the UIO-66, NH2-UIO, and NH2-UIO particles covalently functionalized by Glycidyl Methacrylate (GMA@NH2-UIO), were utilized as the novel functional anti-corrosive fillers. The functionality, high surface area, phase composition, excellent thermal properties as well as chemical stability of the Zr-MOFs were proved by FT-IR, BET, XRD, TGA, and water stability tests, respectively. The smart pH-sensitive controlled-release activity of the corrosion inhibitors (i.e., Zr ions and organic compounds) from the prepared Zr-MOFs was proved by the water stability test of the Zr-MOFs particles in the acidic (pH = 2), neutral (pH = 7.5), and alkaline (pH = 12) solutions containing 3.5... 

Nowadays, the LiNi0.8Co0.1Mn0.1O2 (NCM811) cathode material has attracted great research interest due to its high energy density and less usage of costly raw materials. However, the high nickel content of NCM811 brings about an extremely unstable interface between the electrode and electrolyte and therefore inferior cyclic stability. Herein, we have proposed a straightforward method to deliver 1, 2, and 4 wt % of TiO2 nanoparticles (NPs) on the surface of the NCM811 cathode material and to improve its properties at room and high temperatures. Based on scanning electron microscopy and transmission electron microscopy observations, the coating thickness varies from 10 to 35 nm and the 2 wt %...