Enhanced photocatalytic activity of CuWO4 doped TiO2 photocatalyst towards carbamazepine removal under UV irradiation

Abatement of contaminants of emerging concerns (CECs) in water sources has been widely studied employing TiO2 based heterogeneous photocatalysis. However, low quantum energy yield among other limitations of titania has led to its modification with other semiconductor materials for improved photocatalytic activity. In this work, a 0.05 wt.% CuWO4 over TiO2 was prepared as a powder composite. Each component part synthesized via the sol-gel method for TiO2, and CuWO4 by co-precipitation assisted hydrothermal method from precursor salts, underwent gentle mechanical agitation. Homogenization of the nanopowder precursors was performed by zirconia ball milling for 2 h. The final material was obtained after annealing at 500◦C for 3.5 h. Structural and morphological characterization of the synthesized material has been achieved employing X-ray diffraction (XRD), Fourier transform infra-red (FTIR) spectroscopy, Brunauer–Emmett–Teller (BET) N2 adsorption–desorption analysis, Scanning electron microscopy-coupled Energy dispersive X-ray spectroscopy (SEM-EDS), Transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), and UV-Vis diffuse reflectance spectroscopy (UV-vis DRS) for optical characterization. The 0250.05 wt.% CuWO4-TiO2 catalyst was investigated for its photocatalytic activity over carbamazepine (CBZ), achieving a degradation of almost 100% after 2 h irradiation. A comparison with pure TiO2 prepared under those same conditions was made. The effect of pH, chemical scavengers, H2O2 as well as contaminant ion effects (anions, cations), and humic acid (HA) was investigated, and their related influences on the photocatalyst efficiency towards CBZ degradation highlighted accordingly

Microstructure, microhardness and tensile properties of FSWed DP 800 steel

Purpose: Dual phase (DP) steels are widely used in the automotive industry due to their properties of a high balance of strength and formability. However, it is known that conventional welding of high strength steel leads to some undesirable results such as hardness decrease in the heat affected zone. Friction stir welding (FSW) is a new solid state joining method, which is used to join these steels due to its advantage of low heat input. The aim of this study is to evaluate the microstructural change and mechanical properties of friction stir welded DP800 steel. Design/methodology/approach: DP 800 steels with 1.5 mm thickness were subjected to friction stir welding, by using a tungsten carbide (WC) tool. The tool was tilted 2°, and downforce of the tool was kept constant at 6 kN. During processing, the tool rotation and traverse speed were fixed at 1600 rpm and 170 mm·min-1, respectively. Findings: The friction stir welded region comprises martensite, bainite, refined ferrite. The average microhardness of stir zone has increased from 260 HV0.2 to about 450 HV0.2. The tensile sample shows a decrease in the ultimate tensile strength (?UTS) about 3%, from 827 MPa to 806 MPa for the joint. The yield strength (YS) of the joint is about 566 MPa and the value is near that of DP800. Research limitations/implications: The tungsten carbide tool used for the friction stir welding has suffered deterioration in the pin profile after 1 meter welding operation. It may be advisable to drill a pre-hole in the specimens for a longer tool life. Practical implications: Tool wear for industrial applications will be a major problem. Therefore, the use of tools with high wear resistance such as polycrystalline cubic boron nitride may be recommended. Originality/value: Works on friction stir welding of dual phase steels are limited and they mostly focus on spot welding. Also, this study systematically investigates the microstructure and mechanical properties of dual-phase 800 steels after the friction stir welding. © by International OCSCO World Press. All rights reserved.Karadeniz Teknik Üniversitesi: FBA-2016-5509This study was supported by Scientific Research Projects of Karadeniz Technical University, under Grant No: FBA-2016-5509. Authors would like to than

Investigation of mechanical and microstructural properties of friction stir welded dual phase (DP) steel

2nd International Conference on Material Strength and Applied Mechanics (MSAM) -- MAY 27-30, 2019 -- Kiev, UKRAINEWOS: 000562383900010The application of dual phase (DP) steels has been increasing significantly in the automotive industry because of their high strength as well as good ductility, thus, cold formability. These steels are generally joined using conventional welding methods such as resistance spot welding and laser welding in the production of automotive parts. in recent years, several studies have been conducted to investigate the possibility of joining the advanced high-strength steels such as DP steels using the solid-state friction stir welding (FSW) method due to its advantages over conventional fusion joining methods such as metallurgical benefits, energy efficiency, and environmental friendliness. the aim of this study is to investigate the microstructure, hardness and tensile properties of friction stir welded DP 600 steel plates. Thus, 1.5 mm thick DP 600 steel plates were friction stir butt-welded by a tungsten carbide stirring tool consisting of a concave shoulder having a diameter of 14 mm and a conical pin (angle=30 degrees) with a diameter and length of 5 mm and 1.25 mm, respectively. in the weld trials conducted, the tool was tilted 2 degrees and the down-force of the tool was kept constant at 6 kN. the tool rotation and traverse speeds used in FSW trials were 1600 rpm and 170 mm.min-1, respectively. the microstructure of friction stir welded zone comprised of main martensite, bainite, and refined ferrite. the average hardness of the stir zone has increased to about 400 HV. the tensile specimens failed in the base plate away from the weld zone and tensile strength as high as that of the base plate was obtained from the welded specimens, i.e., about 640 MPa. However, the elongation of the welded plates was significantly reduced, i.e. about 55% of that of the base.Natl Acad Sci Ukraine, Pisarenko Inst Problems StrengthScientific Research Projects Council of Karadeniz Technical University [FBA-2016-5509]This study was financed by the Scientific Research Projects Council of Karadeniz Technical University, under Grant No: FBA-2016-5509. Authors would like to thank Dr. Cemil Gunhan ERHUY and Ermetal Automotive and Goods (ERMETAL) Inc., Bursa, Turkey for their support in supplying the initial material

Growth of Cu 2 ZnSnS 4 (CZTS) thin films using short sulfurization periods

In this study CZTS thin films were grown by a two-stage process that involved sequential sputter deposition of metallic Cu, Zn, and Sn layers on Mo coated glass substrates followed by RTP annealing at 530 and 560 °C for various dwell times (1, 60, and 180 s). CZTS thin films obtained by reaction at different sulfurization temperatures and reaction times were characterized employing XRD, Raman spectroscopy, SEM, EDX, and photoluminescence. It was observed that it is possible to obtain Cu-poor and Zn-rich CZTS thin films with short dwell time of reactions. XRD pattern and Raman spectra of the films showed formation of kesterite CZTS structure and some secondary phases such as CuS, SnS, SnS 2 . The full-width-at-half-maximum (FWHM) values extracted from the (112) diffraction peaks of the CZTS thin films showed that extension of the sulfurization time provides better crystalline quality except for the CZTS560-60 thin film. SEM surface microstructure of the films displayed non-uniform, dense, and polycrystalline structure. The optical band gap of the films as determined by photoluminescence was found to be about 1.36-1.38 eV. © 2019 IOP Publishing Ltd

Friction stir processing of dual phase steel: Microstructural evolution and mechanical properties

Kucukomeroglu, Tevfik/0000-0002-4392-9966; Davut, Kemal/0000-0002-9860-881X; Aktarer, Semih Mahmut/0000-0001-5650-7431WOS: 000483411900009The influence of friction stir processing (FSP) on the microstructure and mechanical properties of a DP 600 steel has been studied. the microstructure evolution during the FSP has been characterized using electron back scatter diffraction (EBSD) technique and scanning and transmission electron microscopes. Standard tension and hardness tests were used to characterize the mechanical properties. the results show that the FSP produced a refined microstructure composed of ferrite, bainite, martensite, and tempered martensite which in turn increased the hardness and strength magnitudes by a factor of 1.5. the initially 2.83 mu m average grain size of ferrite has decreased to 0.79 mu m in the pin effected zone of (PE-SZ-I) of the processed region. Both EBSD and TEM observations showed regions with high dislocation density and sub-structures region in the processed zone. the grain size became coarser, the density of both dislocations and low-angle grain boundaries decrease, away from the processed zone. Moreover, phase fractions and hardness values were predicted using CALPHAD thermodynamic based software based on commercial material properties. Although the prediction does not take into consideration the influence of severe plastic deformation, the results were within 10% uncertainties of the experimental findings. the present study demonstrates that an ultra-fine grained structure can be obtained through the thickness of a 1.5 mm thick D P600 steel sheet via FSP. FSP can produce a range of different hardness and strength values; which can also be predicted successfully by inputting the composition and local temperatures reached during the FSP.Scientific Research Projects of Karadeniz Technical University [FBA-2016-5509]This study was supported by Scientific Research Projects of Karadeniz Technical University, under Grant No: FBA-2016-5509. Authors would like to thank Dr. Cemil Giinhan ERHUY and Ermetal Automotive and Goods (ERMETAL) Inc., Bursa, Turkey for supplying the DP600 steel sheets

Superconducting and levitation force characterisation of pyrene added MgB2 bulk superconductors

This research presents the influence of pyrene (C16H10) addition (0, 2, 4, 6, 8, 10 wt%) on the superconducting properties of bulk MgB2. For C16H10 added MgB2 samples, a shrinkage in a-lattice parameters was determined, whereas c-lattice parameters remained practically unchanged. The (1 1 0) peak observed at 2? ? 59.9? slightly shifted to higher angles, the lattice strain increased and the crystallite size reduced after C16H10 addition. By virtue of induced stronger pinning force, the in-field critical current density (Jc) increased after C16H10 addition. The Jc value at 20 K and 4 T was obtained about two times higher (8.54 × 103 A/cm2) for 4 wt% C16H10 added MgB2 sample than that of the pure one. In addition, the variation of levitation force characteristic of MgB2 with increasing C16H10 content was determined at 20, 25 and 30 K. The best vertical levitation force performance in zero-field-cooled regime was obtained as 7.09 N/g at 20 K for 4 wt% C16H10 added MgB2 sample with 13 mm in diameter. © 2020 Elsevier Ltd2015/2-03 2013/13638, 110T622 Türkiye Bilimsel ve Teknolojik Araştirma KurumuThis research was supported by Bayburt University Scientific Research Projects Coordination Department [Project No: 2015/2-03]. Levitation force measurements were performed by using MLFMS, designed by the project supported by the Scientific and Technological Research Council of Turkey (TUBITAK) [Contract number 110T622 , Patent application number 2013/13638 ]

Growth of Cu2ZnSnS4 (CZTS) thin films using short sulfurization periods

Olgar, Mehmet Ali/0000-0002-6359-8316;WOS: 000457544900001In this study CZTS thin films were grown by a two-stage process that involved sequential sputter deposition of metallic Cu, Zn, and Sn layers on Mo coated glass substrates followed by RTP annealing at 530 and 560 degrees C for various dwell times (1, 60, and 180 s). CZTS thin films obtained by reaction at different sulfurization temperatures and reaction times were characterized employing XRD, Raman spectroscopy, SEM, EDX, and photoluminescence. It was observed that it is possible to obtain Cu-poor and Zn-rich CZTS thin films with short dwell time of reactions. XRD pattern and Raman spectra of the films showed formation of kesterite CZTS structure and some secondary phases such as CuS, SnS, SnS2 . the full-width-at-half-maximum (FWHM) values extracted from the (112) diffraction peaks of the CZTS thin films showed that extension of the sulfurization time provides better crystalline quality except for the CZTS560-60 thin film. SEM surface microstructure of the films displayed non-uniform, dense, and polycrystalline structure. the optical band gap of the films as determined by photoluminescence was found to be about 1.36-1.38 eV

Improvement in levitation force performance of bulk MgB2 superconductors through coronene powder adding

The effect of coronene (C24H12) addition on the levitation force properties of MgB2 superconductor has been investigated for the first time in this study. The polycrystalline disk-shaped MgB2 + y wt % C24H12 samples (y = 0, 2, 4, 6, 8, 10), were synthesized by a pellet/closed tube method at 850 °C under Ar atmosphere, after hot pressing at 200 °C. XRD analysis indicates a decrease in lattice parameters of coronene added samples and confirms substitution of carbon in boron sites. An increase in lattice strain and a decrease in grain size are observed due to the carbon substitution effect. Vertical and lateral levitation force measurements under zero-field-cooled and field-cooled regimes were carried out at different temperatures of 20, 25 and 30 K. It was found that the coronene addition significantly increases the high-field critical current density of MgB2. The Jc values were obtained as 4.6 × 103 Acm?2 and 1.3 × 104 Acm?2 for pure and 4 wt % coronene added samples at 20 K and 4 T. In addition, the levitation force measurements show that 4 wt % coronene adding is very effective in increasing both the vertical and lateral levitation force performances at 20 K. The maximum levitation force for 4 wt % coronene added sample corresponds to 7.58 N/g whereas the reference sample shows 6.73 N/g at 20 K in ZFC regime. The results point out that the hydrocarbon of C24H12 is an effective carbon-containing additive for MgB2 and can be useful for optimizing the levitation performance of MgB2 superconductors for potential applications. © 2017 Elsevier B.V

CZTS layers formed under sulfur-limited conditions at above atmospheric pressure

In this study CZTS thin films were grown by a two-stage process that involved sequential sputter deposition of metallic Cu, Zn, and Sn layers on Mo coated glass substrates followed by RTP annealing in a sulfur atmosphere at background gas pressures in the range of 1–2 atm. Sulfurization was carried out in a mini reaction volume that provided a relatively S-limited environment. Reacted films were characterized using XRD, EDX, SEM, photoluminescence and Raman spectroscopy. It was found that, under the S-limited regime provided in these experiments the Cu-S secondary phase formation was most extreme in the sample grown at 1.5 atm, whereas films grown at lower and higher pressures showed much smaller degree of phase separation. Reaction at 2 atm yielded a compound film that was the closest to the initial precursor in terms of its composition. SEM micrographs showed rough morphology and polycrystalline structure that changed with the sulfurization pressure. The optical band gap of the films as determined by photoluminescence was found to be about 1.37 eV. These experiments demonstrated the importance of the sulfurization pressure as well as the size of the reactor internal volume in determining secondary phase formation in two-stage processed CZTS layers. © 2018 Elsevier Lt

Investigation of magnetic force properties between different PMGs and multi-seeded YBCO superconductors with different seed distances

Kucukomeroglu, Tayfur/0000-0003-4121-9343; ABDIOGLU, MURAT/0000-0002-5497-0817; GUNER, SAIT BARIS/0000-0001-7487-4817; Ozturk, Kemal/0000-0002-8847-1880WOS: 000489690700007The magnetic levitation force in vertical direction and guidance force in lateral direction should be increased for enhancing the loading capacity and stability of Maglev systems, respectively. in this study, we have produced multi-seeded YBCO (YBa2Cu3O7) superconductors with two seeds and investigated the effect of seed distance on the vertical levitation force and lateral guidance force properties by using different permanent magnetic guideway (PMG) arrangements. Although there are studies in literature related to different distance, orientation and angle of seeds; there is no detailed study investigating the effect of seed distance on the vertical and lateral magnetic force properties of Maglev systems depending on different types of PMGs. in this study, after the sample fabrication, the optimum PMG arrangement were determined by using numerical simulation to obtain magnetic flux density distribution. It is determined that both maximum levitation and guidance force values firstly increased with increasing the seed distance from 0 to 4 mm and then related forces decreased with increasing the seed distance from 4 to 16 mm but still keep the higher force values than the sample with the seed distances of 0 mm. This situation is clarified as the increasing of the seed distance to an optimum value enhances both the levitation and guidance forces simultaneously and this is very important for levitation force applications because it causes to easy control of the Maglev system in vertical and lateral directions