Prioritization methodology of dangerous substances for water quality monitoring with scarce data

Monitoring and control of dangerous substances discharged into receiving waters have attracted more attention lately. Since it is not possible to analyze every single substance, a prioritization methodology is needed for the selection of those to be monitored. Existing well-developed models require significant amount of data for reliable outcomes. This paper presents a methodology to prioritize the dangerous substances having adverse effects on freshwaters in Turkey, where data are scarce. Such a methodology will also serve as a solid model for other countries with limited background data. The adopted methodology enabled the elimination of chemicals to generate a candidate list composed of 608 substances among more than 5000 substances. Further screening and prioritization were conducted using different assessment methods (i.e., Total Hazard Value, Total Impact Value, Combined Monitoring-based, and Modelling-based Priority Setting) to obtain a proposed Final Candidate Specific Pollutants List of 150 dangerous substances. The proposed Candidate National Pollutant List of Turkey was established by combining 45 priority pollutants of the European Union with a list of candidate specific pollutants. According to the outcomes of this study, monitoring and controlling of 195 dangerous substances in freshwaters are recommended. Further detailed studies should be conducted in order to observe the actual levels of these dangerous substances in freshwaters followed by a review of the monitoring list accordingly. Moreover, further revisions might be required in the proposed list due to some possible versatile conditions in terms of sampling points (i.e., change in the location of industries).     

Convolutional neural networks for the classification of chest X-rays in the IoT era

Multimedia Tools and Applications - Chest X-ray medical imaging technology allows the diagnosis of many lung diseases. It is known that this technology is frequently used in hospitals, and it is...     

A novel strategy for cartilage tissue engineering: Collagenase-loaded cryogel scaffolds in a sheep model

In this study, we developed a novel strategy, through which cartilage tissue pieces were placed in a sheep cartilage defect model and covered with a collagenase incorporated cryogel scaffold (in vivo cartilage tissue engineering, IVCTE group). While applying this strategy, the chondrocytes could be isolated inside the body and the treatment could be accomplished in one session. To compare our strategy, to another group, in which we used cultured cells and Chondro-gide, standard matrix-induced autologous chondrocyte implantation (MACI) was applied. Although the MACI applied group demonstrated better healing than IVCTE, the type II collagen synthesis was better in the IVCTE group compared to MACI applied group. Collagenase did not have detrimental effect on surrounding cartilage in IVCTE group. The preliminary results of the novel strategy applied group (IVCTE) were promising.     

Effect of carbon nanotube purification on the electrical and mechanical properties of poly(ethylene terephthalate) composites with carbon nanotubes in low concentration

Surface properties of carbon nanotubes (CNTs) were altered by purification with nitric acid, sulfuric acid, ammonium hydroxide, and hydrogen peroxide. As‐received and purified CNT‐based conductive poly (ethylene terephthalate) composites were prepared with a twin‐screw extruder. The effects of CNT purification on the surface properties of the CNTs and on the morphology and electrical and mechanical properties of CNT‐based composites were investigated. Surface energy measurements showed that the acidic component of the surface energies of the CNTs increased after purification. According to Fourier transform infrared (FTIR) spectroscopy, the purification resulted in the formation of oxygen‐containing functional groups on the surfaces of the CNTs. Electron spectroscopy for chemical analysis results indicate the removal of the metallic catalyst residues and an increase in the oxygen content of the CNT surfaces as a result of the purification procedure. X‐ray diffraction analyses revealed a change in the crystalline structure of the CNTs after purification. All of the composites prepared with the purified CNTs had higher electrical resistivities and tensile and impact strength values than the composites based on the as‐received CNTs because of the functional groups and defect sites formed on the surfaces of the CNTs during purification. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Impact damage sensing of multiscale composites through epoxy matrix containing carbon nanotubes

Carbon nanotubes are used to provide increased electrical conductivity for polymer matrix materials, thus offering a method to monitor the structure's health. This work investigates the effect of impact damage on the electrical properties of multiscale composite samples, prepared with woven fiberglass reinforcement and epoxy resin modified with as‐received multi‐walled carbon nanotubes (MWCNTs). Moreover, this study addresses potential bias from manufacturing, and investigates the effectiveness of resistance measurements using two‐ and four‐point probe methods. Transmission electron microscopy and static tensile tests results were used to evaluate, respectively, the dispersion of MWCNTs in the epoxy resin and the influence of the incorporation of these nanoparticles on the static tensile properties of the matrix, and interpret results from the resistance measurements on impacted specimens. In this study, the four‐point probe method is shown to be much more repeatable and reliable than the two‐point probe method. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013     

Improving reinforcement learning by using sequence trees

This paper proposes a novel approach to discover options in the form of stochastic conditionally terminating sequences; it shows how such sequences can be integrated into the reinforcement learning framework to improve the learning performance. The method utilizes stored histories of possible optimal policies and constructs a specialized tree structure during the learning process. The constructed tree facilitates the process of identifying frequently used action sequences together with states that are visited during the execution of such sequences. The tree is constantly updated and used to implicitly run corresponding options. The effectiveness of the method is demonstrated empirically by conducting extensive experiments on various domains with different properties.     

Effect of solid state grinding on properties of PP/PET blends and their composites with carbon nanotubes

In this study, it was aimed to improve electrical conductivity and mechanical properties of conductive polymer composites, composed of polypropylene (PP), poly(ethylene terephthalate) (PET), and carbon nanotubes (CNT). Grinding, a type of solid state processing technique, was applied to PP/PET and PP/PET/CNT systems to reduce average domain size of blend phases and to improve interfacial adhesion between these phases. Surface energy measurements showed that carbon nanotubes might be selectively localized at PET phase of immiscible blend systems. Grinding technique exhibited improvement in electrical conductivity and mechanical properties of PP/PET/CNT systems at low PET compositions. Ground composites molded below the melting temperature of PET exhibited higher tensile strength and modulus values than those prepared above the melting temperature of PET. According to SEM micrographs, micron‐sized domain structures were obtained with ground composite systems in which PET was the minor phase. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Screening of free radical scavenging capacity and antioxidant activities of Rosmarinus officinalis extracts with focus on location and harvesting times

Methanolic extracts from the leaves of Rosmarinus officinalis (rosemary) harvested from different locations of Turkey at four different times of the year were analyzed by HPLC, and their radical scavenging capacities and antioxidant activities were studied by various assays. The amounts of carnosol, carnosic acid and rosmarinic acid, active constituents of rosemary, varied in different geographical regions of growth, and also showed a seasonal variation. The levels of the constituents were higher in the warm months of June 2004 and September 2004. The antioxidant activities of 12 extracts were determined by in vitro DPPH radical scavenging activity, by Trolox equivalent antioxidant capacity (TEAC), and by reversing H₂O₂-induced erythrocyte membrane lipid peroxidation (EMLP). The two antioxidant enzyme activities of human erythrocyte, namely superoxide dismutase (SOD) and catalase (CAT), after in vitro incubation with the extracts, were also examined in order to see whether the observed effects are related to altered enzymatic efficiency. The resulting values were correlated with active metabolite and total phenol contents of the extracts. The results indicated that the plants harvested in September possessing higher levels of active constituent had superior antioxidant capacities compared to the ones collected at other times. With respect to the location, plants harvested from the Izmir region had lower total phenol and active constituent levels resulting in poorer antioxidant activity.     

Effect of composite preparation techniques on electrical and mechanical properties and morphology of nylon 6 based conductive polymer composites

Nylon 6/carbon black conductive composites were prepared using two different methods, masterbatch dilution and melt mixing. Their effect on the size and distribution of carbon black agglomerates in the matrix was studied in terms of electrical and mechanical properties and morphology. The electrical resistivity of composites prepared by both methods decreased with increasing filler composition. The electrical resistivity of the diluted masterbatch composites and the melt mixed composites was reduced from the resistivity of pure nylon 6, 10¹⁵ “ohm, cm”, to 10⁷ “ohm, cm” at 1 and 6 wt % of carbon black, respectively. As the filler content increased, elongation at break and impact strength decreased, but tensile modulus increased. Masterbatch dilution method provided smaller carbon black clusters in composites compared to melt mixing method. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2520–2526, 2006