Application of response surface methodology and artificial neural network on pyrolysis of safflower seed press cake

In this study, mathematical correlation between the process variables and product yields for pyrolysis of safflower seed press cake (SPC) in fixed-bed reactor was investigated by using the response surface methodology (RSM) and artificial neural networks (ANNs). The RSM results showed that the second-order response model can be used to describe the relationship between the various factors and the response. Several feed-forward fully connected neural networks were investigated and optimal configuration of the ANN model was obtained. The results revealed that the ANN model could be considered as an alternative to RSM and practical modeling technique for the pyrolysis product yields.     

Seasonal variation in drinking water concentrations of disinfection by-products in IZMIR and associated human health risks

Seasonal variation in concentrations of two different disinfection by-product groups, trihalomethanes (THMs) and haloacetonitriles (HANs), was investigated in tap water samples collected from five sampling points (one groundwater and four surface water sources) in Izmir, Turkey. Estimates of previously published carcinogenic and non-carcinogenic risks through oral exposure to THMs were re-evaluated using a probabilistic approach that took the seasonal concentration variation into account. Chloroform, bromoform, dibromochloromethane and dichloroacetonitrile were the most frequently detected compounds. Among these, chloroform was detected with the highest concentrations ranging from 0.03 to 98.4 microg/L. In tap water, at the groundwater supplied sampling point, brominated species, bromoform and dibromoacetonitrile, were detected at the highest levels most probably due to bromide ion intrusion from seawater. The highest total THM and total HAN concentrations were detected in spring while the lowest in summer and fall. The annual average total THM concentration measured at one of the surface water supplied sampling points exceeded the USEPA's limit of 80 microg/L. While all non-carcinogenic risks due to exposure to THMs in Izmir drinking water were negligible, carcinogenic risk levels associated with bromodichloromethane and dibromochloromethane were higher than one in million.     

Monodisperse palladium nanoparticles assembled on graphene oxide with the high catalytic activity and reusability in the dehydrogenation of dimethylamine-borane

Highly effective and stable palladium nanoparticles (Pd NPs) supported on graphene oxide (GO) were synthesized, characterized and applied for dehydrogenation of dimethylamine-borane (DMAB). Monodisperse Pd NPs were synthesized with the ultrasonic reduction method in the presence of oleylamine and GO as support matrices at room temperature. Almost uniformly distributed Pd (0) nanoparticles in size of 3.89 nm were isolated in a reproducible manner by filtering through the reaction mixture. They were characterized by TEM, HRTEM, XRD, Raman, and XPS. It was found that Pd@GO NPs are stable and one of the most active catalysts in the dehydrogenation of DMAB. This catalyst with its turnover frequency of 38.02 h^?1 exhibits one of the good results among all the catalysts prepared in the literature for dehydrogeneration of DMAB. Significant activation parameters of the catalytic dehydrogenation reaction were also calculated, and the activation enthalpy (ΔH^#), activation entropy (ΔS^#) and the apparent activation energy (Ea) were found 16.5 kJ mol^?1, ?179 J mol^?1 K^?1, and 18.6 kJ mol^?1, respectively.     

Radiometric dating of sediment cores from a hydrothermal vent zone off Milos Island in the Aegean Sea

Sediment cores from a hydrothermal vent zone off Milos Island in the Aegean Sea were dated using the 210Pb method. The average unsupported 210Pb inventory in the cores was calculated to be 3256 Bq m(-2). The corresponding mean annual 210Pb flux of 105 Bq m(-2) year(-1) is comparable to estimates of the atmospheric flux given in the literature. 210Pb fluxes calculated from the unsupported 210Pb inventories in cores are also comparable with the 210Pb vertical fluxes determined from settling particles off the coast of Milos Island. The highest unsupported 210Pb concentrations (89 Bq kg(-1)) were measured in the sediments nearest to the hydrothermal vent area suggesting that the sedimentation rate is lowest at this site. Direct gamma measurements of 210Pb were used to date three sediment cores that are located at different distances from the vent zone: one is in the immediate vicinity of the vent; and others are outside the zone. Sedimentation rates for these cores, calculated using the CRS and CIC models, ranged from 0.088+/-0.008 cm year(-1) to 0.14+/-0.01 cm year(-1). Where both models were applicable, the results given by the two methods were in good agreement. 137Cs concentrations in all three cores generally declined with depth but showed no clear signal of either the period of maximum fallout from weapons testing or the Chernobyl accident. 210Po activities were also measured and the maximum 210Po concentration was in the sediment surface layer (166 Bq kg(-1)).     

Operational Conditions of Activated Sludge: Influence on Flocculation and Dewaterability

Selected operational conditions of activated sludge are investigated in relation to their effect on flocculation and dewatering. Semi-continuous reactors with 2 -L volume were operated at different mean cell residence times, C/N ratios, and three different influent cations. Results show that MCRT, C/N ratio, and the cation type affect the bioflocculation capacity of activated sludge measured by the quantity of extracellular polymeric substances. As the MCRT value operated in the reactors and the C/N ratio of the influent wastewater increase, total amount of polymers produced increases. High MCRT values and low C/N values cause good dewatering of the sludge. All cations are shown to stimulate the EPS production in a way that the highest total EPS concentrations are observed at the highest cation dosages. The dewaterability of the sludges improves only with increasing calcium and magnesium concentrations and deteriorates with increasing potassium concentration.     

Modified forensic-based investigation algorithm for global optimization

Engineering with Computers - Forensic-based investigation (FBI) is recently developed metaheuristic algorithm inspired by the suspect investigation–location–pursuit operations of police...