PCDD,PCDF and PCB contamination in Atherina boyeri (Risso, 1810) from Turkey

The levels of polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), dioxin-like polychlorinated biphenyls (DL-PCBs) and indicator polychlorinated biphenyls were measured in Atherina boyeri (Risso, 1810) samples collected from Hirfanl? Dam Lake, Turkey in 2008 and 2009.Concentrations of PCDDs–PCDFs were detected as 0.16 and 0.17 pg TEQ₍₁₉₉₈₎ g^?1 wet weight while contamination levels of DL-PCBs were found as 0.42 and 0.38 pg TEQ₍₁₉₉₈₎ g^?1 wet weight in fish samples. The concentrations of total indicator PCBs in fish samples were found as 1.5 ng g^?1 and 0.9 ng g^?1 wet weight. Concentrations of PCDDs–PCDFs and DL-PCBs were below the EU regulation limits.     

Evaluation of hybrid solar-wind-hydrogen energy system based on methanol electrolyzer

In this study, it is aimed to meet the annual electricity and heating needs of a house without interruption with the photovoltaic panel, wind turbine, methanol electrolyzer, and high temperature proton exchange membrane fuel cell system. The system results show that the use of the 2 WT with 18 PV was enough to provide the need of the methanol electrolyzer, which provides requirements of the high temperature proton exchange membrane fuel cell. The produced heat by the fuel cell was used to meet the heat requirement of the house with combined heat and power system. Electrical, thermal and total efficiencies of fuel cell system with combined heat and power were obtained as 38.54%, 51.77% and 90%, respectively. Additionally, the levelized cost of energy of the system was calculated as 0.295 $/kWh with combined heat and power application. The results of this study show that H₂ is useful for long-term energy storage in off-grid energy systems and that the proposed hybrid system may be the basis for future H₂-based alternative energy applications.     

Synthesis and application of dual-curable PVB based adhesive formulations for cord/rubber applications

In this research, formaldehyde-free dual-curable adhesive formulations containing polyvinyl butyral (PVB) were prepared with the reaction of 2,4-toluene diisocyanate (TDI) and 2-hydroxyethyl methacrylate (HEMA) and then applied on cord fabrics upon adhere onto the rubber surfaces. The effects of PVB ratio on peel strength value between the cord and rubber were studied. The structure of the oligomer was characterized by FTIR and ¹H NMR spectroscopy. Thermal properties of coated and UV-cured fabrics were investigated by TGA and DSC. Surface wettability properties of the fabrics after coating were observed with contact angle measurement. The peel strength between cord/rubber surfaces was determined by T-peel test after thermal curing stage under heat and pressure. Results showed that peel strength value increases with increasing PVB amount in the formulation. The highest peel strength of 94.7 N/cm was observed when 5% PVB was included in the formulation. This study leads to a new type of promising adhesives with superior peel strength for cord/rubber applications as it is being a totally formaldehyde-free process.     

Experimental investigation of CO tolerance in high temperature PEM fuel cells

In the present work, the effect of operating a high temperature proton exchange membrane fuel cell (HT-PEMFC) with different reactant gases has been investigated throughout performance tests. Also, the effects of temperature on the performance of a HT-PEMFC were analyzed at varying temperatures, ranging from 140 °C to 200 °C. Increasing the operating temperature of the cell increases the performance of the HT-PEMFC. The optimum operating temperature was determined to be 160 °C due to the deformations occurring in the cell components at high working temperatures. To investigate the effects of CO on the performance of HT-PEMFC, the CO concentration ranged from 1 to 5 vol %. The current density at 0.6 V decreases from 0.33 A/cm² for H₂ to 0.31 A/cm² for H₂ containing 1 vol % CO, to 0.29 A/cm² for 3 vol % CO, and 0.25 A/cm² for 5 vol % CO, respectively. The experimental results show that the presence of 25 vol % CO₂ or N₂ has only a dilution effect and therefore, there is a minor impact on the HT-PEMFC performance. However, the addition of CO to H₂/N₂ or H₂/CO₂ mixtures increased the performance loss. After long-term performance test for 500 h, the observed voltage drop at constant current density was obtained as ～14.8% for H₂/CO₂/CO (75/22/3) mixture. The overall results suggest that the anode side gas mixture with up to 5 vol % CO can be supplied to the HT-PEMFC stack directly from the reformer.     

Donor-acceptor polymer electrochromes with cyan color: Effect of alkyl chain length on doping processes

A new series of donor-acceptor-donor (D-A-D) type compounds consisting of dialkyl substituted 3,4-propylenedioxythiophene and benzothiadiazole units were synthesized and polymerized chemically and electrochemically to investigate the effect of alkyl chain length on the doping process of the conjugated polymers. It was found that the alkyl chain length plays a key role on both doping processes and the solubility of the polymer. It is also noteworthy that this new series of D-A-D electrochromes transmits or reflects the cyan color of the Cyan-Magenta-Yellow (CMY) color space in the neutral state which can be switched to transmissive grey when oxidized.     

Silver and proton driven fluorescent multiple-mode molecular logic gates employing phthalocyanines

Spectral properties and switch behavior of two alkyl thia units bearing Zn (II) phthalocyanine derivatives (Pc-A and Pc-B) were investigated in solvents and in solid matrix of ethyl cellulose by means of absorption and emission spectroscopy. Fluorescence lifetime and fluorescence quantum yield values of the Zn (II) phthalocyanines were calculated. The employed phthalocyanines demonstrated multiple molecular logic gate functions operated by H⁺ and Ag⁺ ions as chemical inputs. The silver driven fluorescence modulation of the Pc-A arises from reversible variations in emission signal intensity at 717 nm. The Pc-B exhibited a similar decreasing emission response to proton and silver ions and an accompanying increasing peak yielding an isobestic point at 746 nm upon protonation. The phthalocyanine doped thin films selectively responded to silver ions in sub-nano and/or pico molar levels. Observed detection limits were 7.6 × 10⁻¹² and 2.3 × 10⁻¹¹ M for Pc-A and Pc-B, respectively. In immobilized phases the attained reversible relative signal changes of Pc-A and Pc-B were 82 and 90%, respectively.     

Biodiesel production from waste chicken fat based sources and evaluation with Mg based additive in a diesel engine

In this study, chicken fat biodiesel with synthetic Mg additive was studied in a single-cylinder, direct injection (DI) diesel engine and its effects on engine performance and exhaust emissions were studied. A two-step catalytic process was chosen for the synthesis of the biodiesel. Methanol, sulphuric acid and sodium hydroxide catalyst were used in the reaction. To determine their effects on viscosity and flash point of the biodiesel, reaction temperature, methanol ratio, type and amount of catalyst were varied as independent parameters. Organic based synthetic magnesium additive was doped into the biodiesel blend by 12 μmol Mg. Engine tests were run with diesel fuel (EN 590) and a blend of 10% chicken fat biodiesel and diesel fuel (B10) at full load operating conditions and different engine speeds from 1800 to 3000 rpm. The results showed that, the engine torque was not changed significantly with the addition of 10% chicken fat biodiesel, while the specific fuel consumption increased by 5.2% due to the lower heating value of biodiesel. In-cylinder peak pressure slightly rose and the start of combustion was earlier. CO and smoke emissions decreased by 13% and 9% respectively, but NO_x emission increased by 5%.     

Growth and mineral acquisition response of grapevine rootstocks (Vitis spp.) to inoculation with different strains of plant growth-promoting rhizobacteria (PGPR)

BACKGROUND: Effects of the plant growth‐promoting rhizobacteria (PGPR) strains Burkholderia gladii BA‐7, Bacillus subtilis OSU‐142, Bacillus megatorium M‐3 and Azospirillum brasilense Sp 245 on vegetative development and mineral uptake of 1103 P and 41 B grapevine rootstocks were investigated. The roots of nursery plants of the grapevine rootstocks were immersed in bacterial solutions and transplanted to a sterilised peat and perlite mixture in 5 L pots. Plants were cultivated in a semi‐controlled glasshouse during the vegetation period. RESULTS: Vegetative development of grapevine rootstocks was obviously promoted by bacterial inoculation, with the maximum increase induced by Sp 245. Inoculation with Sp 245 also significantly improved the chlorophyll concentrations of the leaves of the two rootstocks. Among the bacteria, OSU‐142 also significantly stimulated vegetative development and mineral acquisition of the plants. Nutrient contents of the leaf blades of the plants were generally higher than those of control plants. CONCLUSION: Overall investigations revealed that A. brasilense Sp 245 and B. subtilis OSU‐142 performed more efficiently than the other strains. Therefore these bacteria seem to have considerable potential in reducing the need for inorganic fertiliser. Copyright © 2012 Society of Chemical Industry     

A new low-voltage-driven polymeric electrochromic

Design, synthesis, and properties of a novel donor-acceptor-donor type low-voltage-driven green polymeric electrochrome, P1, which is based on 8-(2,3-dihydrothieno[3,4-b][1,4]dioxin-5-yl)-11-(2,3-dihydrothieno[3,4-b][1,4]dioxin-7-yl)acenaphtho[1,2-b]quinoxaline (1) are highlighted. It is noted that P1 has an ambipolar (n- and p-doping processes) character in 0.1 M tetrabutylammonium hexafluorophosphate/dichloromethane solution and switches to a transmissive blue state upon oxidation. Furthermore, this new polymeric electrochromic candidate exhibits high redox stability, high coloration efficiency and/or contrast ratio, high percent transmittance (%T) and low response time (1.0 s) with a band gap of 1.10 eV-1.25 eV.