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Dehydrogenation of alkane to alkene is a key process in petrochemical industry. Propylene has intermediate role to production many industrial polymers. In this research applying oxidative dehydrogenation method for propylene production and CO2 used as oxidant. By use of XRD, Raman, TEM, BET and EDX techniques the results have been analyzed. In XRD and Raman tests anatase phase and Titania nanotubes have been distinguished. TEM confirmed TiNTs with pure structure. Vanadium catalyst with 5% of vanadia synthesized by impregnation method. Adding silicon in support increased thermal stability of catalyst. Raman and XRD method confirmed good distribution of active phase on supports. VSiTi catalyst have 28.31% conversion and 51% selectivity in 550 oC. Improvement in yield of propylene production would be in result of higher surface area and good distribution of vanadia over modified Titania nanotubes.  

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Research Subject: The conversion of anthropogenous CO₂ gas into value-add chemicals known as solar fuel technology attracted much consideration from the beginning of the 21st century owing to the potential of this technology in solving the climate change and energy shortage issues.
Research Approach: In the current study, Bismuth and copper modified TiO₂ were prepared using sol-gel and wet impregnation method in order to investigate as a catalyst for photocatalytic conversion of carbon dioxide into renewable methane.  
Main Results: The results of X-ray diffraction analysis, Field emission scanning microscope images and Transmission electron microscope images demonstrated that titanium dioxide nanoparticles with 20 nm in size were synthesized that after the addition of bismuth, the size of particles became smaller. Also, using energy dispersive x-ray analysis and elemental mapping technique, it was determined that the bismuth and copper were uniformly inserted in the prepared nanoparticles. Diffuse reflectance spectroscopy showed that the bandgap became smaller in bismuth and copper-containing samples, which resulted in visible light absorption. In addition, photoluminescence spectroscopy showed an impressive decrease in the rate of electron-hole separation in the prepared nanocomposite. The result of CO₂ photoreduction experiments revealed that the incorporation of 3 wt% Bismuth and 1.5 wt% copper into the structure of TiO₂ would increase the amount of methane production to 7.6 times greater than bare TiO₂. This superior activity for methane generation could be related to the ability of bismuth compounds in adsorption and activation of carbon dioxide molecules and also the efficient separation of charge carriers given by copper. Additionally, the smaller particle size and increase in the surface area had also a positive effect on the CO₂ reduction enhancement.

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Research subject: In the present study, titanium dioxide/silver nanocomposites (TiO₂/Ag) were synthesized by sol-gel method and their performance for photocatalytic removal of metribuzin was compared with commercial TiO₂ catalysts P25 Degussa.
Research approach: The synthesized nanocomposites were evaluated using X-ray diffraction spectroscopy (XRD), field emission scanning electron microscopy (FESEM), and energy dispersive X-ray analysis (EDX). The effect of operating parameters including reaction time (0-240 minutes), pH (9-4), catalyst dose (0.005-0.015 g), temperature (10-60 ºC), visible light and UV light radiation, concentration Initial metribuzin (10-25 mg/L), the catalyst effect in the dark, and the amount of silver in TiO₂/Ag nanocomposites (0.10-7% by weight) were investigated on the photocatalytic removal of metribuzin from artificial and real aqueous solutions.
Main results: Laboratory investigations showed that TiO₂/Ag nanocomposite containing 10% by weight of silver, reaction time of 120 minutes, pH equal to 6, catalyst mass of 0.013 g, and initial concentration of 10 mg/L metribuzin are the best properties to maximize the removal of metribuzin in the presence of UV light. The obtained results showed that the synthesized TiO₂/Ag nanocomposite has a higher potential in the degradation of herbicides compared to the commercial TiO₂ nano-catalyst. In addition, the proposed method was used to remove metribuzin injected into the water of the Karun and Zohreh rivers and the wastewater of the sugarcane factory under optimal conditions, and successful results were obtained. Also, the results of using and regenerating the titanium dioxide/silver catalyst three times to remove metribuzin show the high efficiency of this photocatalyst in removing metribuzin from water samples. Comparing the methods available in the literature for the removal of metribuzin with the present method showed that the proposed method is better or comparable to the reported methods.

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Research subject: Osmosis membrane bioreactor is one of the best industrial wastewater treatment methods. The main advantage of using osmosis process is its operation at low hydraulic pressures which has a better performance in removing pollutants and low energy consumption than other methods                        
Research approach: In this research, Nano porous Titanium dioxide powder with a specific surface area and anatase wall was synthesized through a thermal process using cetyltrimethylammonium bromide (CTAB) as a surfactant directing agent and a pore-creating agent.Ultrafiltration nanocomposite membranes were made using modified titanium dioxide (TiO₂) (MT) and polysulfone (PSf) by phase the inversion method. The morphology and structure of the prepared membranes and nanoparticles were investigated using by atomic fourier transforms infrared spectroscopy(FESEM), X-ray diffraction (XRD) and transmission electron microscopy (TEM). In this research, bovine serum albumin (BSA) was used as simulated wastewater for the feed solution. The fabricated ultrafiltration membranes were tested in osmosis membrane bioreactor (OMBR) system due to lower energy and fouling. 0.6 % solution of poly (sodium 4-styrene sulfonate) was used as an osmotic solution. Comparative separation performance and antifouling properties of both nanocomposites in several analyzes such as water contact angle measurement, pure water flux and filtration of different concentrations of bovine serum albumin solution. BSA and fouling resistance have been investigated


Main results:  TThe results that Due to the addition of MT nanoparticles to the polymer matrix, the hydrophilicity and surface energy of the membrane increased, which led to the improvement of the membrane performance. The membrane containing 1% titanium oxide nanoparticles showed the best result. For example, for feeding with a concentration of 200 ppm, the water flux increased from 20 to 38.5 L/ m² h, and the percentage of returning lethal solution decreased from 19.6 to 30 g/ m² h. The flux recovery in this membrane was 96%, which indicates the antifouling property of the modified nanocomposite membrane.                                                                
              

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Backgrounds: This study aimed to assess antibacterial properties of Artemisia scoparia, Titanium dioxide nanoparticles, and their synergistic effect on clinical isolates of Klebsiella pneumonia.
Materials & Methods: In this experimental study, 30 isolates of K. pneumonia were collected from patients’ sputum in the microbiology lab of Masih Daneshvari hospital during 3 months. Then biochemical tests were performed for strain confirming. Moreover, genomic DNA was extracted from all the isolates, and hly gene was detected in the isolates via PCR method. The susceptibility of the isolates to 10 antibiotics was evaluated by the disk diffusion method. Then minimum inhibitory concentration (MIC) of all components (Artemisia extract, TiO2, and their combination) was assessed using the microdilution method against the isolates.
Findings: The results indicated that simultaneous use of hydro-alcoholic extract of A. scoparia and titanium dioxide nanoparticles exhibited a significant synergistic antibacterial effect on 25 clinical isolates in comparison with the use of extract or nanoparticles alone.
Conclusion: It seems that simultaneous use of Artemisia herbal extracts and nanoparticles is beneficial in increasing their antibacterial effect and may decrease antibiotics consumption.

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- In this study, Aluminum closed-cell foam was produced through accumulative roll bonding using TiH2 as blowing agent. Then, the effect of the number of rolling passes, foaming temperature, foaming time and heating rate on percent of porosity was investigated. The results indicate that foaming process improves with increasing temperature. The TiH2 powder was uniformly dispersed into the matrix with increasing the number of roll passes and caused an increase of the percent of porosity. Finally, 41% of porosity at foaming temperature of 680°C, foaming time of 5 min and heating rate of 10(°C)/s was produced.

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Aims: In recent years, awareness of how urban surfaces can improve the microclimate has grown. Meanwhile, the challenge of using cool materials in urban spaces to change the microclimate is significant. Because urban surfaces are made up of two types of vertical surfaces (urban facades) and horizontal surfaces (pavements), each of which has a different impact based on where it is set.

Methods: This research investigates the cooling effect of titanium dioxide (TiO2)-based photocatalytic self-cleaning material (P-S-TiO2) in an urban square. Materials and methods: This study experimentally studied the evaluation of these materials on horizontal and vertical urban surfaces using ENVI-met software in the space of an urban square, a topic unexplored in earlier research.

Findings: The findings show that when these materials were used in the square's pavement, the air temperature of the urban space of the square at the height of 1.5 meters decreased by about 0.6°C because the square's pavement is about 16°C cooler. Meanwhile, the simulation results showed that if these materials are used in the urban facades of the square, there will be no noticeable change in the air temperature.

Conclusion: The conclusion of this research will increase awareness of how to use P-S-TiO2 on both vertical and horizontal surfaces. In other words, using these materials on horizontal surfaces benefits the urban microclimate. Improving the urban microclimate increases the quality of the urban space of JOLFA neighborhood square.

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In this study, various amounts of clay nanoparticles and titan nanoparticles (1, 3 and 5% wt.) were introduced into a vinyl ester resin matrix by high shear mixer. The influence of these nanoparticles on the mechanical properties (tensile strength, tensile modulus, flexural strength, flexural strength and fracture toughness) is investigated. To investigate the structure of nanocomposites, X-ray diffraction (XRD) and transmission electron microscopy (TEM) tests are done. The XRD test shows that the structure of clay-vinyl ester nanocomposites is exfoliated. The results of tensile, flexural and fracture toughness experiments show that clay is better than titan in the improvement of the mechanical properties. Clay- vinyl ester nanocomposite with 1% wt. of clay has the better mechanical properties than others samples.

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In this paper, the process of joining Ti-3Al-2.5V titanium alloy thin sheets by means of micro-plasma arc welding (MPAW) is reported. An experimental set-up was developed using traditional gas tungsten arc welding apparatus and a home-built torch for butt welding of coupon specimens. The specimens were welded under controlled welding parameters, such as voltage, current, travel speed and shielding gas flow rate. An appropriate set of parameters for MPAW process was examined by mechanical properties tests and microstructure characterization. Mechanical tests including tensile test, bending test and micro-hardness evaluation across the weld line generally show that if suitable welding parameters are used, the tensile strength of the welded specimen is well comparable with that of the base metal while its hardness increased at the fusion zone (FZ). The bending test revealed that using appropriate welding parameters, no crack or notch appeared at the welded joint. Fractography, X-ray diffraction and metallograpghy were also performed to study the microstructure evolution. SEM images of the fracture surface presented characteristics of ductile rupture. Studies on microstructure morphology of the specimens at the FZ and HAZ reveal occurrence of phase transformation from high temperature phase to acicular phase

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Abstract- In this study, mechanical and thermal properties of nanocomposites based on polypropylene/ linear low density polyethylene/ nano titanium dioxide (PP/LLDPE/Tio2) were studied. The samples were produced using a co-rotating twin screw extruder including 0,2,4 Wt.% of nano particles, 20,40,60 Wt.% of LLDPE and styrene-ethylene-butylene-styrene(SEBS) as comptabilizer. Tensile properties (modulus, tensile strength and elongation at break), impact resistance and thermal properties (meltingand crystallization temperatures) were evaluated. The results showed that modulus was increased by 9% with addition of nano particles in comparison to PP/LLDPE. In addition, impact resistance was increased and tensile strength and elongation at break were decreased. Melting and crystallization temperatures of PP were increased less or more while, these temperatures for LLDPE did not show meaningful differences.

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Abrasive water jet cutting process can produce tapered edges on cutting kerf. This problem can limit the applications of abrasive water jet cutting process and in some cases it is necessary another edge preparation process. In this paper, an experimental investigation kerf characteristics of Ti-6Al-4V titanium alloy under abrasive water jet cutting is presented. In this regards, it is shown how to use the hybrid approach of Taguchi method and principal component analysis to optimize abrasive water jet cutting are used in this paper. The abrasive water jet cutting process input parameters effect on material removal rate and the characteristics of the surface. A considerable effort was made in understanding the influence of the system operational process parameters such as water jet pressure, traverse speed, abrasive flow rate, and standoff distance. Due to appropriate selecting abrasive water jet cutting process parameters leads to optimizing of kerf characteristics include top kerf width, kerf tapper and kerf deviation, therefore it is important to select appropriate input parameters. The obtained results from this method show that the hybrid approach of Taguchi method and principal component analysis is a suitable solution for optimizing of abrasive water jet cutting process.

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Micromilling is a machining process in manufacturing of the miniature parts. Because of high oxidation and corrosion resistance, high fatigue strength and application of Ti6Al4V in hi-tech industries, in this paper surface roughness and burr formation in micromilling of this alloy have been investigated. Cutting parameters including spindle speed, feed rate and axial depth of cuthave been considered as input parameters of tests. Experiments have been performed for two cases: a) in presence of the minimum quantity lubrication and b) wet conditions. Carbide micro-end mill tool of diameter 0.5 mm and TiAlN coating was used. The Taguchi experimental design method has been used to design and analysis of results. Results showed that the spindle speed and feed rate were the most effective parameters on the surface roughness and burr width of titanium alloy, respectively. Also, by increasing both of these parameters, surface roughness and burr width were decreased. In addition, application of minimum quantity lubrication technique significantly improved the surface quality, and it was more effective in upper levels of spindle speed and axial depth of cut. Finally, the best surface quality was attained in spindle speed of 30000 rpm, feed rate of 0.8 μm/tooth and cutting depth of 60 μm.

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Mathematical modeling is an important step in the design and optimization of process parameters for metal forming. Researchers have been concerned the metal forming limit diagram as an efficient tool to optimize the production of components using forming methods. Due to the low ductility of titanium alloys and wide applications of these alloys in advanced industries such as aerospace, researchers have focused on studying the forming behavior of these alloys. Due to the high cost of experimental methods, especially at high temperatures, numerical methods, has attracted the attention of many researchers. The accuracy of the numerical methods is affected by model of elastic-plastic material behavior. Unusual mechanical behavior of Ti-64 titanium alloys such as high in-plane anisotropy/asymmetry of yield stress and hardening response has been observed. In this paper, the Marciniak model with Cazacu and Hill yield criterions has been used for forming limit prediction. It is observed that the prediction of forming limit using the Cazacu criterion is closer to the experimental results. This is due to the better prediction of the behavior of the titanium alloy, specially Lankford and stress anisotropy coefficients by Cazacu criterion. Cazacu and Hill criterions prediction of Lankford coefficients and yield stresses have been compared.

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Equal channel angular pressing is one of the most effective severe plastic deformation processes for fabrication of ultrafine grained or even nanostructured materials. Among the metallic biomaterials, commercially pure titanium exhibits the best mechanical properties, compared with other alloys. In this study, the effect of work-piece cross section on the mechanical properties of commercially pure titanium produced by this process has been investigated. The work-pieces in two types of cross section(square and circular) are pressed one pass in the square channel with angle 120° at room temperature and effects of cross section on the forming load, grain size, hardness, strength and toughness was studied. Finite element simulation by using the ABAQUS software has been performed for forecasting the forming load, equivalent plastic strain and investigation of effects of geometry parameters of die channel on these. The simulation results have shown good agreement with experimental results. Through analysis of results, it is found that by using the work-piece with circular cross section at equal channel angular pressing process, not only decreased the required pressing load, but also significantly improved the mechanical properties of the materials such as hardness and strength as compared to using the work-piece with square cross section.

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The fabrication of nano‐composites is quite challenging because uniform dispersion of nano‐sized reinforcements in metallic substrate is difficult to achieve using powder metallurgy or liquid processing methods. Friction stir processing (FSP) is a new solid-state process used to modify the refinement of microstructure, improvement of material’s mechanical properties and production of surface layer composites. In this investigation via friction stir processing, metal matrix composite surface (MMCs) was fabricated on surface of 5083 aluminum sheets by means of 5 μm and 80 nm TiO2 particles. The friction processed surface composite layer was analyzed throughoptical and scanning electron microscopical studies. Effects of reinforcing particle size and FSP pass number on the microstructure, microhardness, on tensile and wear properties of the developed surfaces were investigated. Results show that the created nanocomposite layer by TiO2 particles exhibits a microstructure with smaller grains and higher hardness, strength, and elongation compared to the composite TiO2 layer by particles. Increasing FSP pass number results in improved distribution of particles, finer grains, and higher hardness, strength, elongation, and wear resistance. The surface composite layer resulted in four passes with change in rotation direction with nano particle reinforcement exhibited better properties in hardness, tensile behavior and wear resistance compared tothe behavior of the base metal.

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In this study, emulsion films based on pectin were prepared by the casting method, and the effect of titanium dioxide (TiO2) nanoparticles and carnauba wax on the mechanical and the antimicrobial properties of films were studied. The results showed that water vapor permeability was decreased by increasing of nanoparticles. Mechanical tests showed that the tensile strength (TS) of films was lower than control film duo to adding wax carnauba. But TiO2 increased the TS of films. The highest TS was observed in the films incorporating 1% TiO2. Carnauba wax increased the elasticity of films, but TiO2 reduced this parameter. Results showed that both TiO2 and carnauba wax decreased the transparency of films. In the case of the yellow index, carnauba wax increased and TiO2 decreased the “b” value. Antimicrobial test results showed that the inhibitory effect of films against Escherichia coli was increased by the TiO2 and 3% TiO2 had the highest inhibitory effect. Also, the films were studied in terms of morphology and distribution of nanoparticles using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results showed that by increasing the nanoparticle concentration, agglomeration of nanoparticles was increased.

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In this research, carboxymethyl cellulose (CMC)-based nanocomposite films containing montmorillonite (MMT) (1, 3 and 5% wt) were fabricated via casting method.Then, hybrid nanocomposites were prepared by loading dioxide titanium (TiO2) (1, 3 and 5% wt) nanoparticles (NPs) into nanocomposites containing 5% MMT. Moisture content, density, moisture uptake and mechanical properties of the produced films were determined. Also, surface morphology of the nanocompositeswere measured by scanning electron microscopy (SEM).The obtained results indicated that addition of NPs resulted in slightly increase of the films moisture content, and the production of denser samples. Incorporation of 5% MMT decreased moisture uptake of the nanocomposites up to 30%; this decreasing trend was maintained with TiO2 loading. The nanoclays enhanced ultimate tensile strength (UTS) and Young's modulus (YM) of the films at the expense of elongation at break. Addition of TiO2 into MMT-loaded nanocomposites caused to structural weakening and diminishing UTS and YM. SEM micrographs showed well-dispersed MMT and TiO2NPs through the films surface especially at low concentrations. In conclusion, although the films loaded with nanoclays exhibited better properties than the control film, inclusion of TiO2 improved the functional characteristics of them and extended the potential as a biodegradable packaging.

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Titanium alloy Ti-6Al-4V is one of the most used industrial alloys that is used often in important and risky applications. One of the requirements for machining such parts is to achieve the appropriate surface integrity. Powder mixed electrical discharge machining is a process which has different mechanism compared with traditional electrical discharge machining process; and it often used in order to obtain good surface finish. In this study two different kind of Nano powders SiO2 and Al2O3 added in dielectric for machining of Ti-6Al-4V titanium alloy; so that the effect of adding them on the output characteristics of the electric discharge process, including removal rate, tool wear ratio, surface roughness and integrity is investigated and compared. In order to investigate surface micro cracks and heat altered layer, surface and cross section of it were studied by scanning electron microscopy imaging. The results show addition of Nano powders into dielectric, especially SiO2, increases material removal rate, the effect of Nano powders on tool wear ratio depends on machining condition and setting. SiO2 Nano powder decreases surface roughness more than Al2O3 Nano powder. Surface integrity of machined sample in terms of micro-cracks and depth of the heat altered layer is improved with the addition of nanoparticles.