α‐Thiophene end‐capped styrene copolymer containing fullerene pendant moieties: Synthesis,characterization, and gas sensing properties

We report the synthesis, characterization, and gas sensing properties of a styrene copolymer bearing α‐thiophene end group and fullerene (C₆₀) pendant moieties P(S‐co‐CMS‐C₆₀). First, the copolymer of styrene (S) and chloromethylstyrene (CMS) monomers was prepared in bulk via a bimolecular nitroxide‐mediated radical polymerization (NMP) technique using benzoyl peroxide (BPO) as the radical initiator and nitroxy‐functional thiophene compound (Thi‐TEMPO) as the co‐radical and this gave α‐thiophene end‐capped copolymer P(S‐co‐CMS). The chloromethylstyrene units of P(S‐co‐CMS) allowed further side‐chain functionalization onto P(S‐co‐CMS). The obtained P(S‐co‐CMS) was then reacted with sodium azide (NaN₃) and this led to the copolymer with pendant azide groups, P(S‐co‐CMS‐N₃), and then grafted with electron‐acceptor C₆₀ via the reaction between N₃ and C₆₀. The final product was characterized by using NMR, FTIR, and UV–vis methods. Electrical characterization of P(S‐co‐CMS‐C₆₀) thin film was also investigated at between 30 and 100 °C as the ramps of 10 °C. Temperature dependent electrical characterization results showed that P(S‐co‐CMS‐C₆₀) thin film behaves like a semiconductor. Furthermore, P(S‐co‐CMS‐C₆₀) was employed as the sensing layer to investigate triethylamine (TEA), hydrogen (H₂), acetone, and ethanol sensing properties at 100 °C. The results revealed that P(S‐co‐CMS‐C₆₀) thin film has a sensing ability to H₂. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43641.     

Investigation of bismuth doped bioglass/graphene oxide nanocomposites for bone tissue engineering

In this study, bismuth doped 45S5 nanobioactive bioglass (nBG) and graphene oxide (GO) nanocomposites were developed and characterized in terms of microstructural, mechanical, bioactivity and biological properties. Bismuth (Bi) - doped nBG was synthesized by sol-gel method and sintered at 600 °C for 2 h. Nanosized GO was homogeneously mixed with Bi doped bioglass at various ratios to prepare nanocomposites. Addition of Bi increased the density of nBG samples while a considerable decrease in density was observed for nanocomposites with GO incorporation. Bi improved the diametral tensile strength of nBG and addition of 2.5% GO to the composite also increased the diametral tensile strength of the nanocomposites. However, addition of more than 2.5% GO had negative effect on the diametral tensile strength of the composites. Bi doping to bioglass and its composite with GO increased the biocompatibility of 45S5 nBG in which 96.5BG1Bi2.5GO (containing 96.5% BG 1% Bi 2.5% GO in weight ratio) showed highest cell viability. Overall, it can be concluded that composites of Bi doped 45S5 nBG with GO hold promise as biomaterial for biomedical applications.     

Surface Characterization and Biocompatibility of Selenium‐Doped Hydroxyapatite Coating on Titanium Alloy

Selenium‐doped hydroxyapatite (HA) was biomimetically coated on Ti6Al4V plates with the aim of combining the anticancer and antibacterial properties of selenium with the biocompatibility and bioactivity of HA. For the coating process, the composition of 1.5 × SBF (solution with ion concentrations at 1.5 times that of simulated body fluid, SBF) was modified to include 0.15 mM selenate (SeO₄^2?) ion. The selenium‐doped HA coating was characterized by several methods, such as scanning electron microscopy, X‐ray diffraction, and Fourier transform infrared spectroscopy. The cytotoxicity of selenium on osteoblast and osteosarcoma cells was determined. The coating was shown to inhibit the growth of Staphylococcus epidermidis.     

Evaluation of the Parameters of Water Quality with Wavelet Techniques

Generally, wavelets are purposefully crafted to have specific properties that make them useful for signal processing. In recent years, wavelet analysis have commonly been used instead of Fourier analysis. This is a new approach for evaluation of water quality parameters. This study determined water quality parameters and effects on water quality in Gölcük, Turkey. A 13-month data series was compared with results from laboratory analysis by using wavelet model techniques. The study investigated eight surface water sources, located in rural areas (five different villages) in the vicinity of Gölcük. Water samples were obtained during spring and analyzed for contaminants. The samples were analyzed for Cl^- (chlorine), NO₃-N (nitrate) and pH values. Wavelet analysis of extreme events showed the role of seasonal oscillations, and small-, meso- and large-scale effects on some water quality parameters. In addition, the Cl^-, NO₃-N and pH contents were determined for their suitability for irrigation, drinking and other domestic uses.     

An Application of Genetic Algorithm Search Techniques to the Future Total Exergy Input/Output Estimation

Since 1975, there has been a great deal of interest, particularly during the past decade, in the promising genetic algorithm (GA) and its application to various disciplines from medicine to cogeneration. However, the studies performed on energy-related GA modeling are relatively low in numbers. The main objective of the present study is to develop the exergy input/output estimation equations in order to estimate the future projections based on the GA notion. In this regard, the GA Future Total EXergy Input/Output Estimation Models (GAFTEXIEM/GAFTEXOEM) are used to estimate total exergy input/output demand of Turkey, which is selected as an application country, based on the economic and social indicators of gross domestic product (GDP), population, import, export and house production figures. The future prediction of Turkey's total exergy input/output values are projected between 2003 and 2023. It may be concluded that the models proposed here can be used as an alternative solution and estimation techniques to available estimation techniques. It is also expected that this study will be helpful in developing highly applicable and productive planning for energy policies.     

Exergetic analysis and evaluation of a new application of gas engine heat pumps (GEHPs) for food drying processes

In this study, three medicinal and aromatic plants (Foeniculum vulgare, Malva sylvestris L. and Thymus vulgaris) were dried in a pilot scale gas engine driven heat pump drier, which was designed, constructed and installed in Ege University, Izmir, Turkey. Drying experiments were performed at an air temperature of 45 °C with an air velocity of 1 m/s. In this work, the performance of the drier along with its main components is evaluated using exergy analysis method. The most important component for improving the system efficiency is found to be the gas engine, followed by the exhaust air heat exchanger for the drying system. An exergy loss and flow diagram (the so-called Grassmann diagram) of the whole drying system is also presented to give quantitative information regarding the proportion of the exergy input dissipated in the various system components, while the sustainability index values for the system components are calculated to indicate how sustainability is affected by changing the exergy efficiency of a process. Gas engine, expansion valve and drying ducts account for more than 60% amount of exergy in the system. The exergetic efficiency values are in the range of 77.68–79.21% for the heat pump unit, 39.26–43.24% for the gas engine driven heat pump unit, 81.29–81.56% for the drying chamber and 48.24–51.28% for the overall drying system.     

Composite panels containing multiple through-the-width delaminations and subjected to compression. Part II: Experiments & verification

The objective of this investigation was to perform compression tests on laminated composites for verifying the analytical model and the finite element analysis previously developed by the authors for analyzing compression response of composite panels containing multiple delaminations. T300/976 graphite/epoxy composite was selected for the study. Specimens with various ply orientations were fabricated from both flat and cylindrical composite panels containing one to two pre-implanted through-the-width delaminations. Specimens were tested by uniaxial compression, and strain gauges were utilized to record the strain history as a function of the applied load from initial loading to final failure. Numerical simulations were performed according to the test conditions. Comparisons were then made between the predictions and the measured test data. Overall, the predictions agreed with the data very well. Parametric studies were also performed using the finite element analysis to demonstrate the effect of the size, location and number of the delaminations on the compression response of laminated composites.     

Bit Impact Factor: Towards making fair vulnerability comparison

Reliability is becoming a major design concern in contemporary microprocessors since soft error rate is increasing due to technology scaling. Therefore, design time system vulnerability estimation is of paramount importance. Architectural Vulnerability Factor (AVF) is an early vulnerability estimation methodology. However, AVF considers that the value of a bit in a clock cycle is either required for Architecturally Correct Execution (i.e. ACE-bit) or not (i.e. unACE-bit); therefore, AVF cannot distinguish the vulnerability impact level of an ACE-bit. In this study, we present a new dimension which takes into account the vulnerability impact level of a bit. We introduce Bit Impact Factor metric which, we believe, will be helpful for extending AVF evaluation to provide a more accurate vulnerability analysis.     

Effects of Inclination of Bridge Piers on Scouring Depth

For a safe design of a bridge pier footing, it is important to estimate the maximum depth of scour as accurately as possible. The aim of this experimental study is to investigate the effects of inclination of bridge piers on local scour depths around bridge piers. Single circular piers inclined toward the downstream direction were founded in a uniform bed material. Near threshold conditions were employed. The results of this study indicate that the local scour depth decreases as the inclination of the pier increases.