Estimating the bearing capacity of single reinforced granular fill overlying clay

This paper develops an empirical design approach for estimating the footing pressure and settlement behavior of a circular footing on a geogrid reinforced granular fill overlying a weak clay soil by regression analysis. A power model has been developed with a high coefficient of determination R² with 0.959, according to the 398 training data obtained from in-situ tests. The empirical formulation has been evaluated for the validity of the regression model with 220 data which were not used in the derivation of the formulation and the mean absolute percentage error values have been demonstrated that the predictions were obtained with less than 10% error, on average. Additionally, the validity of the developed formulation has been confirmed with different plate load test results from literature, with an acceptable convergence.     

Electrical resistivity and thermal conductivity properties of graphene-coated woven fabrics

In this study, it was aimed to develop electrically and thermal conductive textiles surfaces. Pretreated polyester fabrics were coated with nano graphene powders at different concentration rates (50, 100, and 200 g/kg) by knife over roll technique. Electrical resistivity, thermal conductivity, thickness and mass per unit area measurements, bending rigidity, and abrasion resistance tests of coated fabrics were performed. Surface resistivity measurements of coated fabrics were made according to ASTM D 257 standard with Keithley 8009 Resistivity Test Fixture. Surface electrical resistivity values of coated fabrics decreased with increasing concentration rates. Of note, 2.53 × 10⁴ Ω/sq surface resistivity value was obtained at 200 g/kg graphene concentration rate. Thermal conductivity measurements of coated fabrics were made according to JIS R 2618 standard with Quick Thermal Conductivity Meter (QTM-710). Thermal conductivity property of fabrics improved depending on graphene concentration. The highest thermal conductivity value (0.4243 W/mK) was obtained at 200 g/kg graphene concentration rate. One of the most important results of the study was that a maximum weight loss of 0.40% was observed in the abrasion resistance test even after 100 000 cycles. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 48024.     

CFD-driven surrogate-based multi-objective shape optimization of an elbow type draft tube

Draft tube is the part of Francis turbines which is used to both discharge water and recover kinetic energy at the exit of the runner. A design optimization study of an elbow type draft tube based on the combined use of Computational Fluid Dynamics (CFD), design of experiments, surrogate models and multi-objective optimization is presented in this study. The geometric variables that specify the shape of the draft tube are chosen as input variables for surrogate models and the pressure recovery factor and the head loss are selected as output responses. It is determined that, pressure recovery factor, which is the main performance parameter, can be increased by 4.3%, and head loss can be reduced by %20 compared to the initial CFD aided design. Pressure recovery factor, is represented with a second order polynomial regression model in terms of the geometrical parameters based on the optimization results. The verification of the model is also provided by comparison with CFD results for different draft tubes other than that are used in the development of the model. The model is verified using 30 different design points and it can predict the pressure recovery factor with an error of less than 8%. This model allows the fast and correct design and optimization of elbow type draft tubes, without the need for further CFD simulations.     

Improved Seismic Response of Multisimple-Span Skewed Bridges Retrofitted with Link Slabs

Results of a recent bridge inventory evaluation indicated that about 50% of Turkish highway bridges have more than 30° of skew angle and can be classified as irregular bridges. During the recent major earthquake in Turkey, multisimple-span bridges with continuous decks and link slabs performed well even though these bridges were in the vicinity of the fault line. This study aims to evaluate the improvements in seismic response of skew bridges in terms of forces and displacements when link slabs are added as a retrofit tool. A series of elastic dynamic analyses and nonlinear time history analyses were conducted to investigate the seismic response of various standard highway bridges with different span lengths and skew angles. A new reinforcement design for edge zones of link slabs is proposed for bridges located in high seismic zones. In practice, link slabs can be implemented easily during a regular redecking of a bridge.     

Micro- and nano-encapsulation of limonene and permethrin for mosquito repellent finishing of cotton textiles

Iranian Polymer Journal - The aim of this study was to prepare mosquito repellent textiles. To compare bio-based and synthetic mosquito repellent agents, limonene and permethrin were encapsulated...     

Effect of Strontium and Magnesium Additions on the Microstructure and Mechanical Properties of Al–12Si Alloys

Metals and Materials International - In this study, a binary Al–12Si, eight ternary Al–12Si–Sr, and six quaternary Al–12Si–0.1Sr–(0.2–1)Mg alloys were...     

Phenolic compounds profile and antioxidant activity of Dorystoechas hastata L. Boiss et Heldr

Phenolic compound profile and antioxidant activity of methanol, acetone, ethyl acetate, water and petroleum ether (b.p. 40–60 °C) extracts of Dorystoechas hastata, endemic to Turkey and being consumed as herbal tea by local inhabitants, have been investigated. HPLC–DAD analysis indicated the presence of chlorogenic, caffeic, p-coumaric, ferulic and rosmarinic acids as phenolic acids, quercetin, kaempferol and apigenin as flavonoids and carnosic acid and carnosol as diterpenoid antioxidants in the plant. Petroleum ether, methanol and water extracts of D. hastata were found to be very effective antioxidative extracts. Petroleum ether extract, having the highest amount of carnosic acid and carnosol contents (531.3 and 389.9 mg/g DW, respectively) among all solvent extracts, was found to have the highest antioxidative potential based on the individual antioxidant activity assays; DPPH, ABTS⁺, TBARS and total phenolic content, expressed as IC₅₀, TEAC, EC₅₀ and TPC values, respectively, and also on the principal component analysis. It exhibited significantly high TEAC (7.1 mM trolox) and low EC₅₀ (54.5 μg/mL) values, indicating the strong potential in in vitro radical scavenging and in inhibiting lipid oxidation. Water extract, with its extremely low IC₅₀ value of 4.9 μg/mL in DPPH radical scavenging and significant TEAC (4.8 mM trolox), EC₅₀ (64.4 μg/mL) and TPC (116.7 mg GAE/g DW) values, was found to be the second highest in antioxidative potential among all extracts. TPC value of methanol extract (147.3 mg GAE/g DW) was found to be significantly higher than the other extracts studied. The results showed that D. hastata can be used as a potential antioxidative edible source due to its different classes of phenolic compounds and strong antioxidative capacity.     

RCS2D: A 2D MoM and FDTD‐based scattering simulator

A Java‐based, two‐dimensional electromagnetic (EM) scattering field simulator—RCS2D—is introduced. It enables one to explore EM wave—arbitrary object interaction under a plane wave illumination. RCS2D uses both method of moments and finite‐difference time‐domain models for both transverse magnetic and transverse electric polarizations. © 2013 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013.     

Three-dimensional numerical analysis of geocell reinforced shell foundations

The effects of geocell reinforcement on the behavior of shell foundations were studied using PLAXIS 3D finite element software. For this purpose, conical and pyramidal geometries were adopted as shell foundations. The real honeycomb shape of geocell and rigid body behavior of shells were simulated in PLAXIS 3D. The numerical models for shell foundations and geocell reinforced foundations were separately validated using several laboratory studies in the literature. The validated models were extended to the shell foundations resting on geocell reinforced sandy beds. The inclusion of geocell-reinforcement provided more than 70% reduction in the settlement of pyramidal and conical shell foundations. The stress transferred to the sand beds were reduced and distributed a wider area compared to the unreinforced cases. The maximum improvement in the bearing capacity and the settlement were observed in the case of conical shell foundation. The effect of adopted geocell and shell configuration on the foundation behavior was also analyzed for realistic prototype foundation size.     

Inorganic–Organic Hybrid Materials of Zirconium and Aluminum and Their Usage in the Removal of Methylene Blue

Two novel inorganic–organic hybrid materials, Al-Pydca-3-APDEMS-H and Zr-Pydca-3-APDEMS-H, were prepared by the sol gel method in two steps. In the first step, Al(O^sBu)₂-Pydca and Zr(OPrⁿ)₃-Pydca complexes were prepared from the reactions of aluminum sec-butoxide Al(O^sBu)₃ and zirconium n-propoxide Zr(OPrⁿ)₄ with 2,6-pyridinedicarboxylic acid, respectively. After 3 h of stirring, 3-aminopropyldiethoxymethyl silane (3-APDEMS) and dilute hydrochloric acid were added to the Al(O^sBu)₂-Pydca and Zr(OPrⁿ)₃-Pydca mixtures to hydrolyze the reactions and to form condensation products. These hybrid products were characterized by a combination of Fourier-transform infrared (FT-IR) spectroscopy, powder X-ray diffraction (XRD), scanning electron microscope (SEM), energy-dispersive X-ray (EDX) spectroscopy, Brunauer–Emmett–Teller (BET) analysis, Barrett-Joyner-Halenda (BJH) and other analysis methods. These hybrid materials were used for the removal of methylene blue (MB), a cationic organic dye. The removal efficiency of hybrid materials was measured by UV–Vis spectroscopy.