Sharif Digital Repository

All-solution-processed multilayer ZnO/Ag NWs/ZnO/PVP/PVA composite is introduced as a transparent conductive film (TCF) for optoelectronic applications. Unlike conventional film formation methods that impose high investment expenses, scalable spray coating is applied over the layers using a hand-made spray apparatus. The resulting TCF exhibits high transmittance (T, 86% at 550 nm) and low sheet resistance (Rs, 6 Ω/sq), which is comparable to the sputtered counterparts. The bending test demonstrates the flexibility of the multilayer TCF with no noticeable increase in Rs, even after 1500 bending iterations. Moreover, chemical stability test (exposure to a corrosive agent) and adhesion... 

Moving from two-dimensional hexagonal boron nitride (2D h-BN) flatlands towards their quantum sized zero-dimensional (0D) islands, as the newest member of the h-BN family, has recently opened up novel research areas due to the emergence of unique optical and physicochemical properties, excellent thermal and chemical stability, and desirable biocompatibility. This review elaborates on the fundamental properties of 2D and 0D h-BN nanomaterials and covers the latest progress in the fabrication and applications of BN nanosheets (BNNSs) and quantum dots (BNQDs). Initially, the transformation of properties in h-BN nanomaterials is discussed when moving from the 2D realm towards the 0D quantum... 

Hybrid nanoliquids comprise of better physical strength, mechanical resistance, thermal conductivity, and chemical stability as equated to individual nanoliquids. The present work investigates the MHD laminar flow, containing hybrid nanoparticles, with heat transfer phenomenon over a stretching sheet immersed in a porous medium. The effect of induced magnetic field has also been taken into account. The flow model PDEs are rehabilitated into ordinary ones using a persuasive tool of similarity variables. The analogous system of dimensionless equations alongside the boundary conditions is numerically treated with the Successive-Over-Relaxation (SOR) technique. Flow and heat transfer aspects of... 

Hybrid nanoliquids comprise of better physical strength, mechanical resistance, thermal conductivity, and chemical stability as equated to individual nanoliquids. The present work investigates the MHD laminar flow, containing hybrid nanoparticles, with heat transfer phenomenon over a stretching sheet immersed in a porous medium. The effect of induced magnetic field has also been taken into account. The flow model PDEs are rehabilitated into ordinary ones using a persuasive tool of similarity variables. The analogous system of dimensionless equations alongside the boundary conditions is numerically treated with the Successive-Over-Relaxation (SOR) technique. Flow and heat transfer aspects of... 

Field evidence indicates that the thermal and chemical regimes in wellbore considerably affect the wellbore stability. This study presents a general coupled model for transport of solute, solvent and heat including their combined effects on the wellbore stability. Optimization of drilling fluid parameters is crucial for wellbore stability analysis particularly in high pressure-high temperature environments. The coupled effects of chemical potential and temperature gradients on fluid flow significantly change the pore pressure and stress around a borehole. The effects of various parameters such as mud weight, solute concentration gradient, shale properties, and temperature gradient on... 

Asphaltene precipitation is a major assurance problem posing significant technical and economic loss on petroleum industry. To tackle this issue, various treatments have been proposed and applied by industry. Amongst, inhibiting or retarding the asphaltene precipitation has been understood as the most efficient approach. In this regard, blending crude oil with chemical additives could appreciably heighten its stability. Surfactants, owing to amphiphilic nature, could keep asphaltene dissolved in crude oil by precluding self-tendency of those particles to making agglomerates. Despite importance of this subject, there is still lack of sufficient experimental data to evaluate effectiveness of... 

Condensate and water banking around gas condensate wells result in vital well deliverability issues. Wettability alteration of near wellbore region to gas wetting condition is known to be the most novel and the only permanent method, to improve condensate well productivity. In this work, a water based nanofluid is used to change the wettability of sandstone reservoir rocks from strongly liquid wetting to intermediate gas wetting condition. Static contact angle measurements demonstrated significant increase of liquid phase contact angle as a result of chemical treatment with SurfaPore M nanofluid. The characteristics of SurfaPore M adsorption on sandstone rock are quantified through kinetic... 

Reverse osmosis (RO) membrane process has become the most promising technology for desalination to produce purified water. Among numerous polymeric materials used to fabricate RO membranes, aromatic polyamide thin film composite (TFC) membranes are dominant in commercial RO membrane processes because of their high salt rejection and water permeability as well as their excellent chemical, thermal, and mechanical stability. However, the major hindrance to the effective application of polyamide TFC RO membranes is membrane fouling. Furthermore, polyamide TFC RO membranes have limited stability to chlorine, which is commonly used as disinfect to control membrane biofouling. These two factors... 

Two-dimensional boron nitride quantum dots (2D BNQDs) with excellent chemical stability, high photoluminescence efficiency, and low toxicity are a new class of advanced materials for biosensing and bioimaging applications. To overcome the current challenge about the lack of facile, scalable, and reproducible synthesis approach of BNQDs, we introduce a green and facile approach based on mechanochemical exfoliation of bulk h-BN particles in ethanol. Few-layered hydroxylated-functionalized QDs with a thickness of 1-2 nm and a lateral dimension of 2-6 nm have been prepared. The synthesized nanocrystals exhibit a strong fluorescence emission at 407 and 425 nm with a quantum efficiency of ∼6.2%.... 

Medical engineering advances in total joint replacements and societies’ rising demand for long-lasting materials have proven it essential to manufacture materials that are more similar to the original tissue in the fields of mechanical, tribological, and biological properties. Ultra-high molecular weight polyethylene (UHMWPE) is a polymer widely used in arthroplasty applications due to its biocompatibility, chemical stability, and reasonable mechanical properties; however, it still fails to entirely meet the standards of the hip joint implant. In this study, different concentrations of nanosized zirconia were added to UHMWPE and HAp matrix with an intended application in arthroplasty.... 

Modified perovskite-type oxides were synthesized through co-precipitation and conventional citrate methods. The synthesized perovskite materials had the nominal compositions of LaCoO3, LaCo0.8Cu0.2O3, La0.8Sr0.2Co0.8Cu0.2O 3, and La0.8M0.2FeO3 (where M = Ce and Sr). The catalytic activity of the perovskite samples (for low-temperature CO oxidation) was measured using a quartz reactor with an inlet gas mixture containing 97% N2, 1% O2, and 2% CO. The prepared perovskite samples were characterized by SEM, nitrogen adsorption (BET), XRF, and XRD analyses. The perovskite catalysts showed good structural and chemical stability up to 600 °C and high activity for the catalytic CO oxidation... 

A new non-enzymatic sensor for glucose is prepared by using of Ni(II)-one dimensional coordination polymer (Ni(II)-Cp) and C 60 . The Ni(II)-Cp prepared by slow diffusion and evaporation of two solution layers of NiCl 2 and diaza-macrocycle bearing two pyridine side arms (as the reported tecton) in DMF. The Ni(II)-Cp was characterized by powder x-ray diffraction (PXRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) as well as Fourier transform infrared spectroscopy (FT-IR). C 60 as modified was added to Ni(II)-Cp for improving the electrical and chemical stability of the composite. The newly assembled Ni(II)-Cp/C 60 also coated on glassy carbon electrode (GC) to... 

Zirconium based metal-organic frameworks (Zr-MOFs) are promising candidates for photocatalytic wastewater treatment due to their excellent properties such as high chemical and thermal stability and high photodegradation ability. Herein, we report a novel porous TiO2/ZrO2 photocatalyst derived from UiO-66 and Titania hybrids. UiO-66 nanoparticles was synthesized through solvothermal method and utilized as catalyst support to grow TiO2 particles on its surface. The prepared Titania/MOF nanocomposite was calcined to obtain porous TiO2/ZrO2 photocatalyst for degradation of organic pollutants from colored wastewater under LED visible light. The prepared materials were fully characterized with... 

Medical engineering advances in total joint replacements and societies’ rising demand for long-lasting materials have proven it essential to manufacture materials that are more similar to the original tissue in the fields of mechanical, tribological, and biological properties. Ultra-high molecular weight polyethylene (UHMWPE) is a polymer widely used in arthroplasty applications due to its biocompatibility, chemical stability, and reasonable mechanical properties; however, it still fails to entirely meet the standards of the hip joint implant. In this study, different concentrations of nanosized zirconia were added to UHMWPE and HAp matrix with an intended application in arthroplasty.... 

Engineering the chemical composition of inorganic-organic hybrid perovskite materials is an effective strategy to boost the performance and operational stability of perovskite solar cells (PSCs). Among the diverse family of ABX3 perovskites, methylammonium-free mixed A-site cation CsxFA1-xPbI3 perovskites appear as attractive light-absorber materials because of their optimum band gap, superior optoelectronic property, and good thermal stability. Here, we develop a simple and very effective one-step solution method for the preparation of high-quality (Cs)x(FA)1-xPbI3 perovskite films upon the addition of excess CsCl to the FAPbI3 precursor solution. It is found that the addition of CsCl as a... 

The presence of dyes as pollutants in wastewater sources from textile industries can cause significant health issues if they are not adequately treated. Dye adsorption to entrap contaminants in nanoparticle pores has created considerable attention in recent years due to the environmental concerns occurring as a result of spillage of dyes in water bodies. In efforts to understand adsorption capability UiO-66, metal-organic frameworks (MOFs) were developed and examined for the separation of four pollutant dyes containing methyl red (MR), methyl orange (MO), malachite green (MG), and methylene blue (MB), which are widely used in textile industries. The adsorbent structural stability in water,... 

Promising properties of boron nitride nanomaterials such as their chemical, thermal, and mechanical stability have made them suitable materials in a various range of applications. However, their low electrical conductivity and wide bandgap, particularly in the case of boron nitride quantum dots (BNQDs), have given rise to severe limitations. Efforts on bandgap engineering through doping and surface functionalization have gained little success due to their high thermodynamic stability and inertness. Herein, we present a novel approach to functionalize BNQDs by hydroxyl, methyl, and amine functional groups aiming to adjust the electronic structure. The successful exfoliation is demonstrated by... 

Mg-based metallic glasses are promising materials for biodegradable implants. Understanding atomistic mechanism behind glass formation in these glasses plays a critical role in developing them for future applications. In the present work, we perform a set of molecular dynamics simulations to study structural origin behind glass form ability of Mg-based Mg-Zn metallic glasses at a wide range of compositions. Pair distribution function, Voronoi tessellation and dynamical analysis were adopted to characterize local structures in these glasses. Structural analysis was performed considering both topological and chemical short-range orders. It was found that structure of Mg-Zn metallic glasses... 

Interactions between the metal interconnect and glass sealant in the solid oxide cells stack are critical to retaining the system integrity. To address this issue, in the current study, 8YSZ coating is applied on the Crofer22 APU steel via sol-gel and dip-coating method. Dense and continuous 8YSZ coatings are obtained on Crofer22 APU substrates. X-ray diffraction and Raman spectroscopy results show that both cubic and tetragonal structures of 8YSZ are formed. A glass-based sealing paste is applied on bare and 8YSZ coated Crofer22 APU steel. The interfacial compatibility and chemical stability of steel/glass and steel/8YSZ/glass joint couples are investigated using SEM and EDS line scan... 

One of the key parts of perovskite solar cells which has great influence on their performance and stability is hole transporting layer. Spiro-OMeTAD is extensively used as organic hole transporting material in perovskite solar cells. However, Spiro-OMeTAD is expensive and has low chemical stability. In this study, the solution processed Sb2S3 and Cu3SbS4 nanocrystals have been synthesized and then the n-i-p mesoscopic perovskite solar cells have been fabricated using Spiro-OMeTAD, Sb2S3 and Cu3SbS4 nanocrystals as hole transporting layer at ambient air condition. It is shown that the conduction and valence band levels of the synthesized Sb2S3 and Cu3SbS4 nanocrystals are in the proper...