Effect of feeding pattern on biochemical storage by activated sludge under anoxic conditions

This study investigated the effect of feeding pattern on bacterial storage under anoxic conditions, emphasizing previous adaptation of biomass to a long term feeding condition, under steady-state operation. Storage was evaluated in a sequencing batch reactor (SBR) system operated in a sequence of anoxic/aerobic phases, fed with acetate as the sole carbon source during anoxic conditions. The experimental results indicated that biochemical storage of acetate as PHB occurred when substrate was fed as a pulse, while acetate was removed mostly through direct microbial growth under continuous feeding. For pulse feeding, the anoxic yield, Y(STOD) was calculated as 0.58mg COD (mgCOD)(-1) in two different ways, using mass balances on acetate utilization, PHB generation and nitrate consumption. This value was supported by parallel batch tests and similar results in the literature. Similarly, the rate coefficient for storage under anoxic conditions, k(STOD) was computed as 9.3day(-1) based on basic stoichiometry and model calibration of experimental data. Batch tests conducted with biomass adapted to different feeding patterns showed that substrate storage was insignificant when the feed was added continuously at low concentrations, even if the biomass was previously adapted to storage. Similarly biomass acclimated to continuous feeding could not store the excess substrate although fed instantly. For the operating conditions selected for the study, storage response was significant only with a microbial culture with metabolic activities previously adapted to storage and with short-term substrate feeding at high concentrations.     

Electrospun porous cellulose acetate fibers from volatile solvent mixture

Electrospun porous cellulose acetate (CA) fibers were produced from highly volatile binary solvent system; dichloromethane(DCM)/acetone. The morphology and porous structure of CA fibers were highly dependent on DCM/acetone ratio and the concentration of the solutions. Ribbon-like porous CA fibers were obtained from 5% (w/v) to 10% (w/v) polymer solutions depending on the DCM/acetone ratio; 1/1, 2/1, 3/1 and 9/1 (v/v). Using higher DCM/acetone ratio resulted in bead-free fibers from less concentrated polymer solutions due to the high viscosity of the solutions, in addition, more porous CA fibers were obtained owing to the high volatility of DCM.     

Effect of the atmospheric plasma treatment parameters on jute fabric: The effect on mechanical properties of jute fabric/polyester composites

The effect of atmospheric air plasma treatment of jute fabrics on the mechanical properties of jute fabric reinforced polyester composites was investigated. The jute fabrics were subjected to different plasma powers (60, 90, and 120 W) for the exposure times of 1, 3, and 6 min. The effects of plasma powers and exposure times on interlaminar shear strength, tensile strength, and flexural strength of polyester based composites were evaluated. The greatest ILSS increase was about 171% at plasma power of 120 W and exposure time of 6 min. It is inferred that atmospheric air plasma treatment improves the interfacial adhesion between the jute fiber and polyester. This result was also confirmed by scanning electron microscopy observations of the fractured surfaces of the composites. The greatest tensile strength and flexural strength values were determined at 120 W for 1 min and at 60 W for 3 min, respectively. Moreover, it can be said that atmospheric air plasma treatment of jute fibers at longer exposure times (6 min) made a detrimental effect on tensile and flexural properties of jute‐reinforced polyester composites. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Nanofiber network of electropolymerized 3,4-(2-benzylpropylenedioxy)thiophene on single carbon fiber microelectrode

Electropolymerization of 3,4-(2-benzylpropylene)-dioxythiophene (ProDOT-Bz) on (approximately 7 microm diameter) single carbon fiber microelectrodes (SCFMEs) in different electrolytes resulted the network of nanofiber structure. Electropolymerization performed in different electrolytes by using cyclovoltammetric technique. Surface morphology of coatings was investigated by Scanning Electron Microscopy (SEM), the attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) was used for the characterization. A linear relationship between peak currents of films with polymerization charge, and capacitances and coating thickness were obtained. The size of nanofiber network (and pores) can be controlled by the scan rate of the cyclovoltammetric process. Electrochemical impedance spectroscopic investigation of these nanostructures has been indicated the capacitive behavior of electrode system. Electrochemical Impedance Spectroscopic characterization (Capacitance) of the PProDOTBz/SCFME consisting cell was simulated at applied potential and parameters explained by equivalent circuit modeling.     

Characterization of atmospheric concentrations and partitioning of PAHs in the Chicago atmosphere

An intensive sampling program has been undertaken in the absence of precipitation at an urban site, Chicago, to characterize the atmospheric concentration and partitioning of PAHs. Two different sampling programs have been carried out with a large number of samples. Measured ambient concentrations of PAHs were classified as Land and Lake samples based on wind direction and back trajectory calculations. Differences in ambient concentrations of PAHs were observed between Land and Lake samples. The concentrations of PAHs when air originated over the Land were approximately two-four times higher than the concentrations measured when air originated over the Lake. It has been demonstrated that partitioning of PAHs shows a consistent difference between samples taken when wind came from off the land rather than off the water. This was most evident by more shallow slopes for Lake samples compared to the slopes for Land samples, when partition coefficient (K(p)) is plotted on a log-log scale vs. the subcooled liquid vapor pressure (P(L)(0)). Experimentally, determined K(p) values were compared with the results obtained using two different models, one based on absorption into aerosol organic matter and the other adsorption onto soot carbon. Experimental K(p) values generally agreed well with the soot+octanol based model predictions.     

Air-water exchange and dry deposition of polybrominated diphenyl ethers at a coastal site in Izmir Bay, Turkey

The air-water exchange of polybrominated diphenyl ethers (PBDEs), an emerging class of persistent organic pollutants (POPs), was investigated using paired air-water samples (n = 15) collected in July and December, 2005 from Guzelyali Port in Izmir Bay, Turkey. Total dissolved-phase water concentrations of PBDEs (sigma7PBDEs) were 212 +/- 65 and 87 +/- 57 pg L(-1) (average +/- SD) in summer and winter, respectively. BDE-209 was the most abundant congener in all samples, followed by BDE-99 and -47. Average ambient gas-phase sigma7PBDE concentrations were between 189 +/- 61 (summer) and 76 +/- 65 pg m(-3) (winter). Net air-water exchange fluxes ranged from -0.9 +/- 1.0 (BDE-28) (volatilization) to 11.1 +/- 5.4 (BDE-209) ng m(-2) day(-1) (deposition). The BDE-28 fluxes were mainly volatilization while the other congeners were deposited. Gas- and dissolved-phase concentrations were significantly correlated (P = 0.33-0.55, p < 0.05, except for BDE-209, r = 0.05, p > 0.05) indicating thatthe atmosphere controls the surface water PBDE levels in this coastal environment. Estimated particulate dry deposition fluxes ranged between 2.7 +/- 1.9 (BDE-154) and 116 +/- 84 ng m(-2) day(-1) (BDE-209) indicating that dry deposition is also a significant input to surface waters in the study area.     

Smartphone addiction and its relationship with social anxiety and loneliness

Individuals with psychosocial problems such as social phobia or feelings of loneliness might be vulnerable to excessive use of cyber-technological devices, such as smartphones. We aimed to determine the relationship of smartphone addiction with social phobia and loneliness in a sample of university students in Istanbul, Turkey. Three hundred and sixty-seven students who owned smartphones were given the Smartphone Addiction Scale (SAS), UCLA Loneliness Scale (UCLA-LS), and Brief Social Phobia Scale (BSPS). A significant difference was found in the mean SAS scores (p?<?.001) between users who declared that their main purpose for smartphone use was to access social networking sites. The BSPS scores showed positive correlations with all six subscales and with the total SAS scores. The total UCLA-LS scores were positively correlated with daily life disturbance, positive anticipation, cyber-oriented relationship, and total scores on the SAS. In regression analyses, total BSPS scores were significant predictors for SAS total scores (β?=?0.313, t?=?5.992, p?<?.001). In addition, BSPS scores were significant predictors for all six SAS subscales, whereas UCLA-LS scores were significant predictors for only cyber-oriented relationship subscale scores on the SAS (β?=?0.130, t?=?2.416, p?<?.05). The results of this study indicate that social phobia was associated with the risk for smartphone addiction in young people. Younger individuals who primarily use their smartphones to access social networking sites also have an excessive pattern of smartphone use.