Sharif Digital Repository

In this paper, the impacts of Maxwell nanoliquid transmission, rectangular with titanium oxide nanoparticles are explored over the triangular, chamfer blades. The innovation of this paper is the use of the number of chamfers, rectangular, and triangular blades at the top and bottom of a stretched plate to study physical nanofluid parameters such as temperature and the effects of magnetism. Also, by determining the appropriate height and length for the blades, we achieve the best optimization of temperature and velocity of nanofluid between the plate and the blades, which improves heat transfer and with a more and better effect of magnetic effects. The finite element method is utilized for... 

Rapid population growth and widespread industrialization are the main contributing factors to the increasing contamination of the world’s diminishing freshwater resources. This work investigates Fe/TiO2 as an efficient and sustainable photocatalyst for treating organic micropollutants in water. The photocatalysts prepared by these mechanochemical methods used a high-energy ball milling technique to manipulate Fe/TiO2’s structural, optical, and catalytic properties for the photo-oxidation of 2,4-Dichlorophenol (2,4-DCP). Doping with iron effectively reduced the band gap of rutile TiO2 from 3 to 2.22 eV. By reducing the ball/powder ratio from 34 to 7, the removal efficiency of 2,4-DCP... 

In drilling industry, energy consumption counts from 20 to 40 percent of total costs. Enhanced water-based mud (WBM) drilling fluids with nanoparticles can save energy in drilling processes. An in-house Taylor-Couette flow system (TCS) was developed at Australian University (AU) to study WBM enhanced by Al2O3, SiO2, and TiO2 nanoparticles. The TCS is really a practical tool to help well drillers with a rough idea of viscosity when nanoparticles are added. The TCS for sure cannot substitute advanced rheometry. The goal of the present experiment is to produce a rough estimate in field operation. Experimental results were examined with several rheology models in our previous publications. In... 

Incorporating titanium dioxide (TiO2) nanoparticles into the polymeric matrix offers an opportunity to obtain nanocomposites with improved functionality. In this study, the commercial TiO2 nanoparticles (TNP) were surface treated by different concentrations of aminopropyl triethoxy silane (APTS) as a coupling agent and triethylamine (Et3N) as a surface grafting catalyst by an aqueous process to prepare a nanocomposite with superior properties. Fourier transform infrared spectroscopy (FTIR) and thermogravimetric analysis (TGA) were performed to confirm the successful surface modification of TNP. The prepared modified TiO2 nanoparticles (mTNP) with different weight fractions were used as... 

TiO2 nanotubes (TNTs) were synthesized hydrothermally and modified by Cu2O using a sol-gel method to provide photocatalytic activity in visible light. Cellulose nanofiber (CNF)-based films were prepared by adding TiO2, TNTs, and Cu2O-modified TNT (TNT-Cu2O). The TiO2-based nanoparticles (TiO2, TNTs, and TNT-Cu2O) were uniformly distributed in the base polymer to make compatible and flexible films. The incorporation of nanoparticles significantly enhanced the UV-shielding properties of the film while slightly decreasing the transparency. Incorporating nanofillers improved the film's mechanical and water resistance properties depending on the nanoparticle type. The TNT-Cu2O-added CNF film... 

Preparation of the defective TiO2 nanoparticles (NPs) have been recently in particular interest for its outstanding applications in visible-light active photocatalysis. In order to make TiO2 visible-light absorber, optical band gap should be modified especially via introducing structural defects like oxygen vacancies as an effective pathway. In this research, we prepared defective rutile TiO2 NPs with highly efficient photocatalytic activity under visible light. The NPs were synthesized by electric arc discharge in water as a cost-effective and environmentally friendly method with capability of defect formation which followed by heat treatment. The photocatalytic activity improvement... 

The most common reasons for hard-tissue implant failure are structural loosening and prosthetic infections. Hence, in this study, to overcome the first problem, different bioinspired coatings, including dual acid-etched, anodic TiO2 nanotubes array, anodic hierarchical titanium oxide (HO), micro- and nanostructured hydroxyapatite (HA) layers, and HA/chitosan (HA/CS) nanocomposite, were applied to the titanium alloy surfaces. X-ray diffraction and FTIR analysis demonstrated that the in situ HA/CS nanocomposite formed successfully. The MTT assay showed that all samples had excellent cell viability, with cell proliferation rates ranging from 120% to 150% after 10 days. The HO coating... 

The features of heat transferral capability between metallic (Cu) and non-metallic (TiO2) nanoparticles suspended in the engine-oil (EO) third-grade base-liquid has been analysed under the influence of strong magnetic field. The numerical investigation of system of coupled differential equations for third-grade nanofluid flow model is accomplished via Quasi-linearization method (QLM). The stretching horizontal sheet is heated through convective heat process assuming the special effects of thermal radiation, joule heating, heat generation and viscous dissipation in the energy equation. The mass suction and slip velocity at the boundary of the sheet has been taken into account to enhance... 

Eight eco-friendly, and magnetically-separable heterogeneous photocatalysts including five Au nanoparticles (NPs) modified magnetic TiO2@Fe3O4 NPs and three Ag-Au bi-plasmonic NPs-decorated TiO2@Fe3O4 NPs with enhanced photocatalytic performance under visible light were synthesized and used for photodegradation of methyl orange (MO) as a model pollutant in textile wastewater samples. The photocatalytic activity was assessed using two radiation sources namely, an intense linear 532-nm laser and a continuous solar-simulated xenon lamp. Compared to the TiO2 alone, the prepared photocatalysts revealed efficient photocatalytic activity in visible region due to the presence of two localized... 

Titanium dioxide (TiO2) and Cu-doped TiO2 (Cu–TiO2) were synthesized using a sol-gel method and used as nanofillers to prepare CMC-based functional packaging films. The Cu–TiO2 was spherical particles with a size range of 66.1 ± 9.0 nm TiO2 and Cu–TiO2 nanoparticles had good compatibility with CMC and were evenly distributed in the CMC polymer matrix to form a composite film. The TiO2-added film did not show significant antibacterial activity, but the Cu–TiO2-added film exhibited high antibacterial activity against foodborne pathogenic bacteria (L. monocytogenes and E. coli) under visible light. When bananas were packaged with the CMC-based films, the CMC/Cu–TiO2 film effectively delayed the... 

For the first time this work reports a new idea to develop a round-the-clock self-cleaning coating which was successfully applied to preserve cultural heritage and modern artifacts under sunlight illumination and at night. To fabricate this structure, namely, H2:TiO2/WO3@Pt, soft templating and hydrogen treatment approaches were selected to enhance the performance of TiO2/WO3 photocatalyst, together with the addition of Pt plasmonic nanoparticles. The coating can be photochemically charged in the presence of sacrificial electron donors and keep its stability, benefiting from the remained electrons stock for over 10 h to clean the surface from aggressive pollution also at night, in absence of... 

The necessity of research in food and nutrition and the emergence of diabetes mellitus call for fast and efficient glucose detection. Here, series of highly sensitive non-enzymatic photoelectrochemical glucose sensor based on engineered titanium dioxide nanotube arrays has been synthesized using a simple electrochemical approach to tune nanotubes morphology in a way that the highest sensitivity factor (525.5 µAmM−1cm−2) and saturation concentrations (0.18 mM) achieved in the photoelectrochemical sensor. The formation of oxygen-rich titanium oxide was confirmed by several techniques. Dependent on the growth condition, nanotube length changed from 1.9 to 8.4 µm while their inner diameter... 

Sufficient quantity of trace metals is essential for a well performing anaerobic digestion (AD) process. Among the essential trace elements in active sites of multiple important enzymes for AD are iron and nickel ions. In the present study, iron and nickel in the form of Fe2O3 and NiO were coated on TiO2 nanoparticles to be used in batch and continuous operation mode. The effect of TiO2, Fe2O3–TiO2, and NiO–TiO2 nanoparticles on each step of AD process was assessed utilizing simple substrates (i.e. cellulose, glucose, acetic acid, and mixture of H2–CO2) as well as complex ones (i.e. municipal biopulp). The hydrolysis rate of cellulose substrate increased with higher dosages of the coated... 

The synthesis of nanocomposites via in situ grafting polymerization due to its ability to produce polymeric materials with promising microscopic and macroscopic characteristics is becoming very attractive. In this paper, different poly(L-Lactide)-block-poly(ε-caprolactone) (PLLA-b-PCL) copolymers were in situ synthesized in the presence of modified titanium dioxide (TiO2) nanoparticles (mTNP) as the initiator and stannous octoate as the catalyst. The surface of TiO2 was modified by grafting aminopropyl trimethoxy silane to improve initiator efficiency. Copolymers with 90/10, 70/30, and 50/50 mass ratio of L-lactide/ ε-caprolactone and 5 wt% of mTNP (proportional to ε-caprolactone) were... 

Efficient sunlight harvesting is of great significance for environmental remediation through photocatalysis. Herein, very small (20 nm) upconverter SrF2:Yb,Tm@CaF2:Yb@Fluorine-doped TiO2heteronanoparticles (denoted as UCNPs@TiO2) with strong UV-blue emission and broadband photocatalytic performance were prepared via a facile three-step hydrothermal method for the first time. The SrF2:Yb,Tm upconverter nanoparticles (NPs) were produced as the light-emitting core, epitaxially grown CaF2:Yb as the middle shell to enhance the upconversion luminescence output and TiO2as the photocatalyst outermost layer. Superior photocatalytic functioning of UCNPs@TiO2was affirmed through methylene blue (MB)... 

In the present research, we investigate the synergistic effects of Ru-doping and Ar/H2 reduction treatment on the photoelectrochemical water splitting performance and hydrogen evolution rate of TiO2 nanotube array photoelectrodes. The Ti-Ru alloy with 0.2 at. % Ru was used to grow anodic self-organized Ru-doped TiO2 nanotube layers. An ideal synergy between Ar/H2 reduction treatment and Ru-doping results in the extended absorption toward the visible light region and improved photoelectrocatalytic activity. The black Ru-doped TiO2-x photoanode's water splitting rate improves remarkably (∼ninefold) compared to the black TiO2-x sample (∼twofold). Moreover, the black Ru-doped TiO2-x photoanode... 

The nanofibers prepared by electrospinning process have high potential for the removal of toxic matters from wastewaters. In the present study, the titanium dioxide and titanium dioxide/zinc oxide (TiO2/ZnO) nanofibers prepared by electrospinning technique were coated on the sewage sludge carbon (SSC) surface for adsorption of Ni(II), Cu(II), and COD from aqueous solutions and industrial wastewaters of Iran. The synthesized adsorbents were characterized using XRD, SEM and EDX analysis. The effect of adsorbent type, pH, adsorbent dosage, contact time and initial concentrations of Ni(II), Cu(II) and COD on the adsorption capacity of synthesized SSC/TiO2 and SSC/TiO2/ZnO nanofibrous adsorbents... 

Crystalline anatase TiO2 nanoparticles were synthesized in the gas phase using an H2O-assisted atmospheric-pressure CVS process. Simultaneous oxidation/hydrolysis of TiCl4 in the H2O-assisted APCVS process demonstrates the feasibility of facile fabrication and the designed synthesis of TiO2 nanoparticles in atmospheric pressure. Kinetics and thermodynamics studies of TiCl4 reactions in the gas phase illustrated oxidation or hydrolysis domination theoretically and were confirmed by experimental runs. Effects of H2O/O2 ratio on the reactions mechanisms, phase formation, size characteristics, morphology, and purity of TiO2 nanoparticles were experimentally studied using various analytical... 

Power consumption of wellbore drilling in oil and gas exploitations count for 40% of total costs, hence power saving of WBM (water-based mud) by adding different concentrations of Al2O3, TiO2 and SiO2 nanoparticles is investigated here. A high-speed Taylor–Couette system (TCS) was devised to operate at speeds 0–1600 RPM to simulate power consumption of wellbore drilling using nanofluids in laminar to turbulent flow conditions. The TCS control unit uses several sensors to record current, voltage and rotational speed and Arduino microprocessors to process outputs including rheological properties and power consumption. Total power consumption of the TCS was correlated with a second-order... 

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 %...