Modeling of fretting wear evolution in rough circular contacts in partial slip

This paper presents a numerical model that maps the evolution of contact pressure and surface profile of Hertzian rough contacting bodies in fretting wear under partial slip conditions. The model was used to determine the sliding distance of the contacting surface asperities for one cycle of tangential load. The contact pressure and sliding distance were used with Archard's wear law to determine local wear at each surface asperity. Subsequently, the contact surface profile was updated due to wear. The approach developed in this study allows for implementation of simulated and/or measured real rough surfaces and study the effects of various statistical surface properties on fretting wear. The results from this investigation indicate that an elastic–perfectly plastic material model is superior to a completely elastic material model. Surface roughness of even small magnitudes is a major factor in wear calculations and cannot be neglected.     

Morphology enhancement of TiO2/PVP composite nanofibers based on solution viscosity and processing parameters of electrospinning method

In this work, different sol solutions with various titanium tetraisopropoxide (TIP)/glacial acetic acid ratios in 2‐propanol with 5 wt % poly(vinyl pyrrolidone) (PVP) (M_w = 360,000 g/mol) were prepared and electrospun. Composition of the prepared sols and as‐spun TiO₂/PVP nanofibers were determined by Fourier transform infrared and Raman spectroscopy methods. Morphology of the electrospun TiO₂/PVP nanofibers was studied by scanning electron microscopy and transmission electron microscopy (TEM) techniques. Rheometry measurements of the sol solutions showed decrease of viscosity upon the addition of TIP to the polymer solutions with constant polymer and acid concentrations. The sol solution having the lowest viscosity (at shear rate 10 s^?1) but the highest TIP/glacial acetic acid ratio showed beaded nanofibers morphology when electrospun under 10 and 12 kV applied voltage while injection rate, needle tip to collector distance, and needle gauge were kept constant. However, smooth electrospun TiO₂/PVP composite nanofibers with the average nanofibers diameters (148 ± 79 nm) were achieved under the same condition when applied voltage increased to 15 kV. TEM micrographs of the electrospun TiO₂/PVP nanofiber showed that the TiO₂ particles with continuous structure are formed at the middle of the nanofiber and distributed along its axis. © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 46337.     

A Simple and Efficient Method for the Synthesis of 2-Aminothiazoles Under Mild Conditions

NEt₃ was found to be a simple, mild, and efficient catalyst for the synthesis of 2-aminothiazole derivatives from the reaction of different ketones, thiourea, and iodine in EtOH media under mild conditions for the first time. Present methodology offers several advantages, such as simple procedure, shorter reaction times, and milder conditions, and takes place at reflux temperature, with operational simplicity and with excellent yields.     

Investigation of the soil amplification factor in the Adapazari region

Turkey is located on the highly active Eurasian plate. A very active strike slip fault, the North Anatolian Fault Zone (NAFZ), crosses Turkey from east to west; earthquakes occurred on this fault on August 17, 1999 (Kocaeli) and November 12, 1999 (Düzce). Regional geology and subsoil conditions can significantly change the characteristics of ground motion. For this reason, determining soil amplification during an earthquake, especially for soft soils, is a very important topic for researchers. In this study, one dimensional ground response analyses were performed for selected Adapazari sites using the August 17, 1999 Kocaeli earthquake strong ground motion record with SHAKE2000 software. Soil characteristics and depth to engineering bedrock at the selected sites are different and the observed level of structural damage at these sites during the Kocaeli earthquake was also different. Calculated soil surface response spectrums at these sites were compared with the recommended design spectra of the Turkish Earthquake Code and the Eurocode 8. According to one dimensional ground response analyses, the calculated response spectra of the selected sites exceed the recommended design spectra of the Turkish Earthquake Code and the Eurocode 8. Calculations show that higher amplification ratios occur at higher periods due to soil behaviour. Results of this study indicate that local geological conditions may amplify ground motion at some periods and, due to this amplification, the calculated response spectra may exceed the recommended design spectra. Therefore, it is clear that local site conditions must be considered for earthquake-resistant engineering designs on soft alluvial soil deposits.     

Investigation of immiscible CO2 and C1 injection and comparison with water injection for enhanced oil recovery in naturally fractured reservoirs

Reservoir oil and gas content tends to rise up to the surface as long as their potential energy levels are sufficient. In order to amplify this energy, either during the time when oil is uprising on its inherent energy or since after, so as to facilitate the traveling of oil to the surface, enhanced oil recovery (EOR) methods come into play. Furthermore, the increasing demand for oil from one hand, and the shrinkage of producible reserves on the other hand, have made it unavoidable to undertake EOR techniques. Built in this research was a 10-element model of reservoir fluid to simulate its behavior. Furthermore, slim tube simulation was undertaken to determine minimum miscibility pressure for various gases. Then, different scenarios of natural depletion, CO₂ injection, methane injection, and water injection were simulated by ECLIPSE 300 software package with the results of different scenarios compared. The results indicated water injection to be associated with higher recovery factor.     

Deep Neural Networks Regularization Using a Combination of Sparsity Inducing Feature Selection Methods

Neural Processing Letters - Deep learning is an important subcategory of machine learning approaches in which there is a hope of replacing man-made features with fully automatic extracted features....