Effect of Ti amount on wear and corrosion properties of Ti-doped Al2O3 nanocomposite ceramic coated CP titanium implant material

Al₂O₃ and Ti-doped Al₂O₃ nanocomposite ceramic coatings were prepared by using a sol-gel dip-coating process. Corrosion and wear resistance of Al₂O₃ ceramic coatings in relation to Ti amount were carried out using pin-on-disk tribotester, potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). Surface characterizations before and after the corrosion and wear tests were investigated by the scanning electron microscope (SEM) and X-ray diffraction (XRD) and hardness analysis. The results of corrosion and wear tests exhibited that the corrosion and wear resistance of nanocomposite ceramic coatings became better than uncoated samples. Also, corrosion and wear resistance of nanocomposite ceramic coatings improved with Ti doping content increased.     

Elimination of boron and lithium coexisting in geothermal water by adsorption-membrane filtration hybrid process

Direct release of geothermal waters to the environment may cause some damages to some plants because they contain toxic species such as boron, arsenic, fluoride etc. along with valuable minerals including lithium. In this study, a hybrid process combining adsorption and membrane filtration was used to separate boron and lithium simultaneously from geothermal water. According to the results obtained, separation efficiencies for lithium and boron from geothermal water were 100% and 83% using boron selective ion exchange resin Dowex XUS-43594.00 and lithium selective λ-MnO₂ adsorbent, respectively. The kinetic data of lithium and boron adsorption have been evaluated using pseudo-first order and pseudo-second-order kinetic models.     

Color of absence and presence: Reconsidering black in architecture

Abstract: This article explores the effects of using black on spatial experience by means of phenomenological analysis of its architectural examples with a special focus on Serpentine Gallery Pavilion designed by Peter Zumthor. Contrary to the growing interest in the color in contemporary architecture, black rarely found a place in architectural history and in studies on color design. Whereas, the distinct achromatic qualities of the color that appear highly self‐contradictory swinging back and forth from absence to presence cover a wide range of potentials to be used in architectural design. Through insights delved into the spatial experience constructed around these qualities, this paper attempts to analyze how black is used as a design element in built environments. This analysis revolves around Zumthor s pavilion, which stood as a uniform black box on the expanse of green grass of London Kensington Gardens for more than three months in 2011. Encompassing various oppositions, the box built to surround a hortus conclusus, an enclosed garden inside, provided its visitors with a unique spatial experience depending predominantly on the combination of its form, tectonics and the qualities of its color, black. The phenomenological analysis of these qualities manifests that the architect utilized the contradictory characteristics of the color intentionally in order to create a complex and manifold spatial experience for visitors in and outside the box. In an interplay of absence and presence, momentary crystallizations of the vision of black provide architects with uncharted opportunities for creative use of color in the design of built environments. © 2016 Wiley Periodicals, Inc. Col Res Appl, 42, 378–387, 2017     

Properties of pumice aggregate concretes at elevated temperatures and comparison with ANN models

The mechanical properties and thermal conductivity of concretes including pumice aggregate (PA) exposed to elevated temperature were analyzed by thermal conductivity, compressive strength, flexure strength, dynamic elasticity modulus (DEM) and dry unit weight tests. PA concrete specimens were cast by replacing a varying part of the normal aggregate (0–2 mm) with the PA. All concrete samples were prepared and cured at 23 ± 10C lime saturated water for 28 days. Compressive strength of concretes including PA decreased that reductions were 14, 19, 25 and 34% for 25, 50, 75 and 100% PA, respectively. The maximum thermal conductivity of 1.9382 W/mK was observed with the control samples containing normal aggregate. The tests were carried out by subjecting the samples to a temperature of 0, 100, 200, 300, 400 500, 600 and 700 °C for 3 h, then cooling by air cooling or in water method. The results indicated that all concretes exposed to a temperature of 500 and 700 °C occurred a significant decrease in thermal conductivity, compressive strength, flexure strength and DEM. An artificial neural network (ANN) approach was used to model the thermal and mechanical properties of PA concretes. The predicted values of the ANN were in accordance with the experimental data. The results indicate that the model can predict the concrete properties after elevated temperatures with adequate accuracy. Copyright © 2016 John Wiley & Sons, Ltd.     

Effect of Ozonated Water Treatment on Fatty Acid Composition and Some Quality Parameters of Olive Oil

The organic olives from Çine-Ayd?n (Turkey) were washed with tap or ozonated water for 2 and 5 min, respectively, and pressed to olive oil. The effects of wash treatments on fatty acid composition and several quality parameters of the oils were determined. The maximum values after 2-min ozonated water washes were 9.58 meqO₂/kg, 0.73%, 2.44 and 0.16 for peroxide, free acid, K₂₃₂ and K₂₇₀ values, respectively, which were under the standard limits for extra-virgin olive oil. Five min of ozonated water washes also yielded acceptable results, except for a slight excess on K₂₃₂ value. Ozonated water washes had almost no effect on fatty acid composition.     

Effect of layer thickness on the electrical parameters and conduction mechanisms of conjugated polymer‐based heterojunction diode

In this study, thickness‐dependent current density–voltage (J–V) characteristics obtained for poly{(9,9‐dioctylfluorene)?2,7‐diyl‐(4,7‐bis(thien‐2‐yl) 2‐dodecyl‐benzo[1,2,3] triazole)} (PFTBT) conjugated copolymer based heterojunction diode fabricated on ITO were investigated in terms of electrical characteristics. In order to analyze J –V plots with ITO/PEDOT:PSS/PFTBT:PC₆₁BM/LiF/Al configuration, the thickness‐dependent J–V measurements were applied in the thickness range between 90 and 200 nm. The effect of PFTBT:PC₆₁BM layer thickness on the forward J –V characteristics were investigated by evaluating electrical parameters such as zero bias barrier height (Φ_Bo), ideality factor (n ), shunt resistance (R _sh), series resistance (R_s ), the interface states density (N _ss), and space‐charge limited mobility. The results show that at PFTBT:PC₆₁BM layer thickness of 90 and 200 nm, ideality factor for ITO/PEDOT:PSS/PFTBT:PC₆₁BM/LiF/Al heterojunction diodes ranged from 2.726 to 3.121 and the thermionic emission over the heterojunction diodes is crucial at low current densities and the intrinsic thermally generated charge carriers controlled the forward current this region of the heterojunction diode. At relatively higher voltage, the current mechanism of ITO/PFTBT:PC₆₁BM/PEDOT:PSS/LiF/Al heterojunction diodes were found to obey a space charge limited (SCLC) conduction mechanism. The values of N_ss and R_s in heterojunction diodes increase with increasing PFTBT:PC₆₁BM layer thickness and effect the main electrical parameters of diodes. In addition, the leakage current of heterojunction diodes are taken and interpreted via Poole‐Frenkel emission and Schottky emission. The leakage current was controlled in ITO/PEDOT:PSS/PFTBT:PC₆₁BM/LiF/Al heterojunction diodes by Poole‐Frenkel emission above 140 nm and by Schottky emission under 140 nm. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44817.     

Spectroscopic and conductometric studies on the interactions of thionine with anionic and nonionic surfactants

In this study, the interaction of thionine, a cationic dye, with anionic [sodium dodecyl sulphate (SDS), lithium dodecyl sulphate (LiDS), and sodium dodecylbenzene sulphonate (SDBS)], nonionic (Tween 20 and Triton X‐100), and binary mixtures of anionic and nonionic surfactants was studied by conductometric and spectrophotometric measurements. The degree of ionisation, the counterion binding parameters, and the equilibrium constants in the premicellar region were obtained from conductivity data. Binding constants of thionine to anionic, nonionic, and mixtures of anionic and nonionic micelles were determined by spectrophotometric measurements. The binding tendency of thionine to anionic micelles followed the order SDBS > SDS > LiDS. The presence of nonionic surfactants increased significantly the binding affinity of thionine to anionic micelles, and the highest binding constant was calculated in the presence of Tween 20. The results obtained from conductometric studies correlated with those obtained from spectroscopic studies. Data concerning dye–surfactant interaction are important for a fundamental understanding of the performance of single and mixed surfactants and for their industrial application.     

Application of ozone gas for the stripping of fabric ink‐jet‐printed with reactive dyes

In this study, a novel process utilizing ozone was carried out for colour stripping of fabrics misprinted with reactive dyes in ink‐jet machines. The results of ozone applications were compared with conventional colour stripping process performed by thiourea dioxide (TUDO) and soda ash. In trials, cotton‐based and viscose‐based woven fabrics were used as these fabrics were the most utilized at the textile mill in which this study was performed. Different ozone treatment times (30, 45, 60 or 90 min) were tested to find optimum process time and it was found that process times depended on fabric type. Particularly, colour stripping on high density and thick fabrics were harder than low density and thin fabric types. Fabric strengths, whiteness indexes and chemical oxygen demand (COD) values were measured. Also energy, chemical and water consumptions were calculated. Consequently, it was found that the reduction of the COD value of effluent was up to 98%. The calculations showed that the savings in time and cost in ozone treatment were up to 77%. Satisfactory colour stripping and tensile strengths were achieved.     

Photoluminescence characterization and heat treatment effect on luminescence behavior of BaTa2O6:Dy3+ phosphor

Undoped and Dy³⁺‐doped barium tantalate phosphors were synthesized by the solid‐state reaction method at 1425°C. Also, 10 mol% Dy³⁺‐doped BaTa₂O₆ was sintered between 1150 and 1425°C in order to determine temperature effect on structural and luminescence properties. Afterwards, they were characterized by XRD, SEM‐EDS and photoluminescence (PL) analyses. PL spectra exhibited the excitation peaks between 300 and 440 nm. Two typical emissions were observed at 486.2 nm (blue) and 577.7 nm (yellow) due to the ⁴F_9/2→⁶H_15/2 and ⁴F_9/2→⁶H_13/2 transitions, respectively. Emission intensities increased with increasing doping concentration of Dy³⁺ up to 10 mol% and then decreased due to the concentration quenching effect. Moreover, depending on the increase in heat treatment temperature, the intensity of emission reached maximum at 1425°C. The calculated CIE chromaticity coordinates of phosphors located in the white light region.