Isolation of some active compounds from Origanum vulgare L. ssp. vulgare and determination of their genotoxic potentials

Origanum vulgare L. (oregano) is a flavoring herb widely used around the world. In the present study, crude extract of O. vulgare L. (oregano) and its petroleum ether, chloroform, ethyl acetate, n-butanol, water fractions were prepared in order to isolate and investigate antimutagenic compounds from the active extract through the bacterial genotoxicity assay guided fractionation procedures. The methanol extract and its n-butanol fraction showed significant antimutagenic activity. In the end of sub-fractionation process of the n-butanol extract, luteolin 7-O-glucuronide and luteolin 7-O-xyloside were isolated. These compounds showed significant antimutagenic activity against 9-Aminoacridine and N-Methyl-N′-nitro-N-nitrosoguanidine mutagenicity. The inhibition rates ranged from 22.1% (luteolin 7-O-xyloside: Salmonella typhimurium TA1537 – 0.4 mM/plate) to 67.8% (luteolin 7-O-glucuronide: S. typhimurium TA1537 – 0.8 μM/plate). In conclusion, the results revealed that luteolin 7-O-glucuronide and luteolin 7-O-xyloside are two of the antimutagenic compounds of O. vulgare L. ssp. vulgare.     

Reduction of Cogging Force in Linear Permanent-Magnet Generators

Although linear permanent-magnet generators (LPMGs) are widely used for converting wave energy into electrical energy, they suffer from large cogging force. The cogging force causes oscillatory output power, which shortens lifetime and increases the maintenance costs of the generators. To reduce this force in the generator, we have designed and simulated a three-phase LPMG for direct wave energy conversion and predicted its performance using the finite-element method. We studied the influence of different design parameters on the cogging force and minimized this force by varying the proposed parameters. The results obtained confirm a large reduction in the cogging force and an enhancement in the generator performance.     

Artificial neural networks for automotive air-conditioning systems performance prediction

In this study, ANN model for a standard air-conditioning system for a passenger car was developed to predict the cooling capacity, compressor power input and the coefficient of performance (COP) of the automotive air-conditioning (AAC) system. This paper describes the development of an experimental rig for generating the required data. The experimental rig was operated at steady-state conditions while varying the compressor speed, air temperature at evaporator inlet, air temperature at condenser inlet and air velocity at evaporator inlet. Using these data, the network using Lavenberg–Marquardt (LM) variant was optimized for 4–3–3 (neurons in input–hidden–output layers) configuration. The developed ANN model for the AAC system shows good performance with an error index in the range of 0.65–1.65%, mean square error (MSE) between 1.09 × 10^?5 and 9.05 × 10^?5 and the root mean square error (RMSE) in the range of 0.33–0.95%. Moreover, the correlation which relates the predicted outputs of the ANN model to the experimental results has a high coefficient in predicting the AAC system performance.     

Application Oriented Multi Criteria Optimization in WSNs Using on AHP

With the increasing number and variety of Wireless Sensor Network (WSN) applications the need to define a suitable protocol design model that fits their specific requirements and operation has become even more pressing. The traditional methods and the well known OSI layered model prove to be inadequate for WSNs. Utilizing cross layer interactions on the other hand leads to increased efficiency in operation and prolonging the network lifetime. Similarly, proper optimization can even further add to improving the performance and reducing energy consumption in WSN. However there is no common ground to compare the suggested solutions or there is no well defined methodology for determining the optimization parameters for each specific case. In this paper we discuss two major issues: the first one is definition of optimization parameters for WSN and check for their consistency, the second one is how the suggested approach can be incorporated in a cross layer framework to provide adaptivity to different application requirements while maximizing the network performance and prolonging the network lifetime.     

Synthesis,characterization, and colloidal properties of polythiophene/borax conducting composite

In this study, synthesis of polythiophene (PT) and polythiophene/borax pentahydrate (PT/borax) conducting composite were carried out by in‐situ oxidative polymerization. The composite was subjected to various characterization techniques namely: FTIR, particle size, magnetic susceptibility, density, conductivity, dielectric, TGA, XRD, SEM, and zeta (ζ)‐potential measurements. The effects of time, pH, various surfactants, electrolytes and temperature on the ζ‐potential of PT and PT/borax composite were investigated. In a basic medium the ζ‐potential of the composite was observed to decrease up to ζ = −66.5 mV. The most effective surfactant on the ζ‐potential of the composite was sodium dodecyl sulfate, which reduced the value of ζ‐potential to ζ = −39.2 mV. It was concluded that the presence of mono‐valent (NaCl) salt has no impact on ζ‐potential whereas, di‐valent (BaCl₂) salt shifted the ζ‐potential value to more positive regions. Elevated temperatures caused almost no change on the ζ‐potential of the composite. Also an electrorheological effect (a tremendous viscosity increase) was determined from the PT/borax colloidal systems under an externally applied electric field, and the results obtained will be discussed in the forthcoming article. POLYM. COMPOS., 2011. © 2010 Society of Plastics Engineers     

Suitability of acid whey for fermented and fresh-pack cornichon pickle production

Suitability of acid whey (AW) as brine media in fermented and fresh-pack cornichon pickle production was investigated. Fermented and fresh-pack pickles were produced with AW and vinegar (control). Microbiological, textural, colour and sensory properties of the pickles were monitored during 12-wk storage at room temperature. Fermented and fresh-pack pickles manufactured with AW exhibited higher total solids content than the pickles manufactured with vinegar. Acid whey as pickling media increased the development of presumptive lactococci species both in fermented and in fresh-pack pickles. This study shows that AW is a suitable pickling media for fermented and fresh-pack cornichon pickle manufacture.     

Characterization of polypyrrole/azocalix[4]arene salts: Electrical properties and thermal stability

Polypyrrole (PPy) was doped with the azocalix[4]arene [(5,11,17,23‐tetrakis[(p‐carboxyphenyl)azo]25,26,27,28‐tetrahydroxycalix[4]arene)] host species. PPy/azocalix[4]arene salts were characterized by FTIR, TGA, SEM, X‐ray diffraction, and conductivity measurements. The properties of PPy were investigated in the presence of azocalix[4]arene host species. The conductivity of PPy increased in the presence of azocalix[4]arene. TGA results indicated that the PPy/azocalix[4]arene salts have higher thermal stability than PPy. It was observed from SEM analysis that the particle diameter of PPy decreased with increasing content of azocalix[4]arene. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

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.     

Fluorene‐Carbazole Dendrimers: Synthesis,Thermal, Photophysical and Electroluminescent Device Properties

Novel hole‐transporting dendrimeric molecules containing dioctylfluorene, spirobi(fluorene) and spiro(cylododecane‐fluorene) as the core unit and different numbers of carbazole and thiophene moieties as the peripheral groups are synthesized. All the dendrimers are characterized by ¹H NMR, ¹³C NMR, FTIR, UV–vis, PL spectroscopy, and MALDI‐TOF. They are thermally stable with high glass transition and decomposition temperatures and exhibit chemically reversible redox processes. They are used as the hole‐transporting layer (HTL) material for multilayer organic light emitting diodes (OLEDs) with a low turn‐on voltage of around 2.5 V and a bright green emission with a maximum luminance of around 25400 cd m^?2.     

Performance analysis of fast reclosing transients in inductionmotors

Induction motors are used extensively in heavy industry. For these loads, this often requires reclosing on the motor before it reaches zero speed. However, if the supply voltage is applied before the motor reaches zero speed, the motor can be damaged due to excessive current and torque transients. This paper presents a performance analysis of fast reclosing transients in induction motors. It is shown that the optimum time instant for reclosing depends upon the supply voltage and load parameters. The results indicate that the maximum absolute value of instantaneous torque occurs in the first cycle and for every time cycle of supply voltage. In fact, there are at least one positive peak and one negative peak for the torque