Quantifying selected growth parameters of Leptothrix discophora SP-6 in biofilms from oxygen concentration profiles

It is a dubious but common practice to use growth parameters measured in suspended cultures to predict substrate concentration profiles in biofilms. To obtain biofilm biokinetic parameters that apply to biofilms, a reliable method is needed that allows the computation of biokinetic parameters from substrate concentration profiles measured directly in biofilms. We have developed such a method and demonstrated its utility by evaluating biokinetic parameters from oxygen concentration profiles measured in biofilms of Leptothrix discophora SP-6 grown on a membrane, which was placed on top of an agar plate by fitting the data to Monod or Tessier growth kinetics, including maintenance substrate consumptions. We found that the Monod model represented the growth of L. discophora SP-6 biofilms marginally better than the Tessier model. The Monod half saturation coefficient was .     

Characterization of poly(vinylferrocenium) coated surfaces and their applications in DNA sensor technology

Poly(vinylferrocenium) (PVF⁺) modified gold (Au) electrode was developed in this study for the electrochemical sensing of deoxyribonucleic acid (DNA) hybridization based on the oxidation signals of polymer and guanine, and also for the electrochemical investigation of interaction of anticancer drug, mitomycin C (MC) and DNA immobilized onto PVF⁺ modified Au electrode. PVF⁺ modified Au electrode was prepared by electrooxidation of poly(vinylferrocene) PVF at +0.7 V versus Ag/AgCl reference electrode. The polymer modified electrode and DNA immobilized polymer modified electrode were characterized by X-ray photoelectron (XPS), Fourier transform infrared-attenuated total reflentance (FTIR-ATR) and alternating current (AC) impedance spectroscopy. For application studies, differential pulse voltammetry (DPV) technique was used.     

Efficient Path Delay Test Generation for Custom Designs

Due to the rapidly growing complexity of VLSI circuits, test methodologies based on delay testing become popular. However, most approaches cannot handle custom logic blocks which are described by logic functions rather than by circuit primitive elements. To overcome this problem, a new path delay test generation algorithm is developed for custom designs. The results using benchmark circuits and real designs prove the efficiency of the new algorithm. The new test generation algorithm can be applied to designs employing intellectual property (IP) circuits whose implementation details are either unknown or unavailable.     

Uranium immobilization by sulfate-reducing biofilms grown on hematite, dolomite, and calcite

Biofilms of sulfate-reducing bacteria Desulfovibrio desulfuricans G20 were used to reduce dissolved U(VI) and subsequently immobilize U(IV) in the presence of uranium-complexing carbonates. The biofilms were grown in three identically operated fixed bed reactors, filled with three types of minerals: one noncarbonate-bearing mineral (hematite) and two carbonate-bearing minerals (calcite and dolomite). The source of carbonates in the reactors filled with calcite and dolomite were the minerals, while in the reactor filled with hematite it was a 10 mM carbonate buffer, pH 7.2, which we added to the growth medium. Our five-month study demonstrated that the sulfate-reducing biofilms grown in all reactors were able to immobilize/reduce uranium efficiently, despite the presence of uranium-complexing carbonates.     

NMR spectroscopy of ozonated wastewaters obtained from steaming of Fagus silvatica

NMR ¹H and ¹³C spectroscopy was successfully used to monitor the ozonation of wastewaters generated during the steaming treatment of green lumber of beech wood (Fagus sylvatica). A noticeable diminution of signals from aromatic cycle was observed. An increase of the carbonyl and carboxyl group was also noticed. The signals from the carbohydrates were constant after the ozonation. This study clearly suggest that ozonation is an effective means to degrade the phenolic compounds generated during the steam treatment.

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NMR- Spektroskopie ozonisierter Abwässer von dampfbehandelter Buche (Fagus silvatica)

Zusammenfassung ¹H und ¹³C NMR-Spektroskopie wurden erfolgreich eingesetzt, um die Ozonisierung von Abwässern, die während der Dampfbehandlung von waldfrischem Buchenschnittholz (Fagus silvatica) entstehen, zu registrieren. Eine deutlich merkbare Verminderung der Signale aromatischer Ringe wurde beobachtet. Eine Zunahme der Carbonyl- und Carboxyl-Gruppen wurde ebenfalls beobachtet. Die Signale der Kohlenhydrate waren nach der Ozonisierung konstant. Diese Untersuchung weist deutlich darauf hin, dass die Ozonisierung eine wirksame Methode zum Abbau phenolischer Komponenten darstellt, die während der Dampfbehandlung entstehen.

     

Procedure for determining maximum sustainable power generated by microbial fuel cells

Power generated by microbial fuel cells is computed as a product of current passing through an external resistor and voltage drop across this resistor. If the applied resistance is very low, then high instantaneous power generated by the cell is measured, which is not sustainable; the cell cannot deliver that much power for long periods of time. Since using small electrical resistors leads to erroneous assessment of the capabilities of microbial fuel cells, a question arises: what resistor should be used in such measurements? To address this question, we have defined the sustainable power as the steady state of power delivery by a microbial fuel cell under a given set of conditions and the maximum sustainable power as the highest sustainable power that a microbial fuel cell can deliver under a given set of conditions. Selecting the external resistance that is associated with the maximum sustainable power in a microbial fuel cell (MFC) is difficult because the operator has limited influence on the main factors that control power generation: the rate of charge transfer at the current-limiting electrode and the potential established across the fuel cell. The internal electrical resistance of microbial fuel cells varies, and it depends on the operational conditions of the fuel cell. We have designed an empirical procedure to predict the maximum sustainable power that can be generated by a microbial fuel cell operated under a given set of conditions. Following the procedure, we change the external resistors incrementally, in steps of 500 omega every 10, 60, or 180 s and measure the anode potential, the cathode potential, and the cell current. Power generated in the microbial fuel cell that we were using was limited by the anodic current. The anodic potential was used to determine the condition where the maximum sustainable power is obtained. The procedure is simple, microbial fuel cells can be characterized within an hour, and the results of the measurements can serve many purposes, such as: (1) estimating power generation in various MFCs, (2) comparing power generation in MFCs using different electroactive reactants, (3) quantifying the effects of the operational regime on the power generation in MFCs, and finally, (4) the purpose for which the procedure was designed, optimizing the performance of existing MFCs.     

Particle filter-based aerial tracking for moving targets

This paper considers the problem of tracking a moving target with a radio transmitter using an aerial robot in an online manner. The aerial robot is equipped with a low-cost directional antenna and Software Defined Radio receiver to obtain the signal emitted by the target. The aerial robot rotates around itself and collects a predefined number of signal recordings from each direction to determine the bearing angle to the target in which the received signal strength is maximized. The measurement uncertainty is assumed to be bounded and represented by two triangular areas divided by a bisector. To localize and track the target, a particle filter-based approach is proposed. In this approach, we integrate the discrete and bounded measurement model with the particle filter in such a way that the particles' weights are updated based on a novel method which considers the measurement wedge and the particle locations with respect to this wedge along with a logistic function. We also incorporate the doubling strategy into the particle filter to determine the next measurement locations and avoid arbitrarily large number of measurements. We choose wildlife monitoring as a use case scenario in which a radio transmitter is put on the animal under consideration to allow wildlife researchers to track it. Since each animal has its own motion behavior, we consider different motion models for the target, which are used in modeling animal movements in wildlife studies. Therefore, the proposed approach is validated using a target moving with varying velocity and acceleration. We verified the tracking performance of the approach through a series of extensive simulations. We compared the proposed approach with the optimal offline strategy in terms of the empirical competitive ratio of the total distance traveled and the tracking distance. We also developed a low-cost hardware platform and software infrastructure for the proposed tracking system. Using this platform, we conducted field experiments for the stationary and moving targets.     

Effects of Ozone Treatment on Microbiological Quality and Physicochemical Properties of Turkey Breast Meat

ABSTRACT

The effects of ozone treatment (1 × 10^?2 kg m^?3, for up to 8 h) on quality parameters of turkey meat were investigated. Ozone was effective in inactivating microorganisms. Approximately 2.9, 2.3 and 1.9 log reductions were achieved in the counts of total aerobic mesophilic bacteria, Enterobacteriaceae and yeast-mold, respectively. Ozone caused significant changes in carbonyl contents, thiobarbituric acid reactive substances, color and pH values of the samples. Water holding capacity and cooking yield of treated samples increased significantly (p < .05). This is the first report demonstrating that quality parameters of turkey breast meat are markedly affected by ozone treatment.     

Service-orientation in electronic markets

This special theme aims to analyze the linkage between service-orientation and electronic markets. On the one hand, questions focus on how service-oriented thinking and service-oriented solutions provide value to electronic markets, and on the other how electronic markets improve the effectiveness of service industries, such as healthcare, telecommunications, logistics, education, and others. While the papers in the special theme section highlight selected aspects of a services-based business transformation, this preface discusses main underlying assumptions of the service evolution, underpins the link between service-orientation and electronic markets, and concludes with some developments on the emerging trans-disciplinary field of service science.     

Characterization and strain‐energy‐function‐based modeling of the thermomechanical response of shape‐memory polymers

Shape‐memory polymers (SMPs) are an emerging class of active polymers that can be used on a wide range of reconfigurable structures and actuation devices. In this study, an epoxy‐based SMP was synthesized, and its thermomechanical behaviors were comprehensively characterized. The stress–strain behavior of the SMP was determined to be nonlinear, finite deformation in all regions. Strain‐energy‐based models were used to capture the complicated stress–strain behavior and shape‐recovery response of the SMP. Among various strain energy functions, the stretch‐based Ogden model provided the best fit to the experimental observations. Compared to the sophisticated models developed for SMPs, the strain‐energy‐based model was found to be reliable and much easier to use for practical SMP designs. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41861.