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Among 50 bacterial isolates obtained from maize rhizosphere, 13 isolates belonged to the genus Azotobacter. Isolates were biochemically characterized and estimated for pH and halo tolerance ability and antibiotic resistance. According to characterization, the six representative isolates were selected and further screened in vitro for plant growth promoting properties: production of indole-3-acetic acid (IAA), siderophores, hydrogen cyanide (HCN), exopolysaccharides, phosphate solubilization and antifungal activity (vs. Helminthosporium sp., Macrophomina sp., Fusarium sp.). Beside HCN production, PGP properties were detected for all isolates except Azt 7 . All isolates produced IAA in the medium without L-tryptophan and the amount of produced IAA increased with concentration of precursor in medium. The highest amount of IAA was produced by isolates Azt 4 (37.69 and 45.86 µg ml -1 ) and Azt 5 (29.44 and 50.38 µg ml -1 ) in the medium with addition of L-tryptophan (2.5 and 5 mM). The isolates showed the highest antifungal activity against Helminthosporium sp. and the smallest antagonistic effect on Macrophomina sp. Radial Growth Inhibition (RGI) obtained by the confrontation of isolates with tested phytopathogenic fungi, ranged from 10 to 48%. Među 50 izolata bakterija iz rizosfere kukuruza, 13 izolata pripadali su rodu Azotobacter. Izolati su biohemijski karakterisani i ispitana je tolerantnost prema reakciji sredine, koncentraciji soli i rezistentnost na antibiotike. Nakon karakterizacije, odabrano je šest reprezentativnih izolata za dalja ispitivanja PGP svojstava: produkcije indol-3-sirćetne kiseline (IAA), siderofora, cijanovodonične kiseline, egzopolisaharida, fosfosolubilizacije i antifungalne aktivnosti (prema Helminthosporium sp., Macrophomina sp., Fusarium sp.). Osim produkcije HCN, PGP svojstva utvrđena su za sve izolate osim Azt 7 . Najveću količinu IAA produkovali su izolati Azt 4 (37,69 i 45,86 µg ml -1 ) i Azt 5 (29,44 i 50,38 µg ml -1 ) u podlozi sa dodatkom L-tryptophan-a (2,5 i 5 mM). Izolati su ispoljili najveću antifungalnu aktivnost prema Helminthosporium sp., a najmanji antagonostički efekat prema Macrophomina sp. Procenat inhibicije rasta (RGI) dobijen suočavanjem izolata sa ispitivanim fitopatogenim gljivama kretao se od 10 do 48%.

The anthraquinone dye, C.I. Acid Blue 111, was subjected to electrochemical oxidation using an IrOx electrode and sodium sulphate or sodium chloride as electrolytes. The effects of different operating parameters on the rate of dye decolorization, such as applied current, electrolyte concentration, and initial pH were studied. The dye concentration during the study was followed via ultraviolet-visible spectroscopy. The changes in the dye molecule during electrochemical oxidation were analyzed by Fourier Transformation-infrared spectroscopy. The level of mineralization after electrochemical oxidation was established by total organic carbon analysis. Correction to “Direct and Indirect Electrochemical Degradation of Acid Blue 111 Using IrOx Anode” Int. J. Electrochem. Sci., 12(2017)8564-8577; doi: [http://dx.doi.org/10.20964/2017.09.44]

The control of anti-lock braking system is a great challenge, because of the nonlinear and complex characteristics of braking dynamics, unknown parameters of vehicle environment and system parameter variations. Using some of robust control methods, such as sliding mode control, can be a right solution for these problems. In this paper, we introduce a novel approach to design of ABS controllers, which is based on digital sliding mode control with only input/output measurements. The relay term of the proposed digital sliding mode control is filtered through digital integrator, reducing the chattering phenomenon in that way, and the additional signal of estimated modelling error is introduced into control algorithm to enhance the system steady-state accuracy. The given solution was verified in real experimental framework and the obtained results were compared with the results of implementation of two other digital sliding mode control algorithms. It is shown that it gives better system response, higher steady-state accuracy and smaller chattering.

A new class of lowpass linear-phase FIR filter function given in an explicit compact form is introduced. First, the general form of a new class of n th-order difference equations with all real coefficients equals one is proposed, and after that the simple frequency sampling structure for any odd and even orders of the filter is designed. Finally, several simulation experiments have been performed in order to compare this filter with other known filters for the same values of free real integer parameters. It should be highlighted that the new filters compare favourably even with the already existing filters, because they have an insert attenuation of 158 dB, 15.1681% lower cutoff frequency of the passband of the filter, and 18.5313% lower cutoff frequency of the stopband of the filter, for an insert loss of 100 dB.

A new ultra-selective lowpass finite impulse response (FIR) filter function is proposed. First, a new difference equation with all coefficients equals one, and the general structure of the corresponding linear-phase lowpass digital filter is given. Then, the high economical realisation with only four adders and without multipliers, for any filter order is presented. The concrete example of the proposed filter, compared to the already existing filters, demonstrates a higher selectivity, lower passband and circuit of lower complexity.

Oxygen reduction was investigated at FeTMPP–Cl adsorbed on the Black Pearls carbon and heat-treated at temperatures from 200 to 1000°C. Kinetic parameters of the reaction and the dependence of the reaction rate on the heat-treatment temperature were established in acid and alkaline media. It was found that the O2 reduction rate increases with increase in the heat-treatment temperature of the electrocatalyst, reaching a plateau at 700≤T≤1000°C. The reaction rate was higher in alkaline solution on all electrocatalysts examined, but its dependence on the heat-treatment temperature was the same as in acid media. Like similar other macrocycle catalysts, FeTMPP–Cl/BP was found to be methanol-tolerant. The effect of sulfate, perchlorate, and phosphate anions was also investigated and no influence on the reaction rate was found. Activities of FeTMPP–Cl/BP and Pt/BP electrocatalysts were compared. FeTMPP–Cl/BP heat-treated at 700≤T≤1000°C showed similar activity to Pt/BP if they are compared in alkaline solution, but in acid solution, the reaction rate on the Pt electrocatalyst was higher. The controversy in the literature on the role of metallic Fe particles in O2 reduction catalysis is discussed. Comparison of present results with previous cyclic voltammetry and TEM investigations of the same electrocatalyst gave further evidence that some other products of the heat-treatment are responsible for the high activity of the catalyst.

Iron(III) tetramethoxyphenyl porphyrin chloride adsorbed on the Black Pearls carbon (FeTMPP‐Cl/BP) was heat‐treated at temperatures from 200 to 1000°C in Ar atmosphere and characterized by using cyclic voltammetry, X‐ray photoelectron spectroscopy (XPS), and transmission electron microscopy (TEM) techniques. Cyclic voltammetry experiments were carried out in acidic and alkaline solutions. Redox peaks due to the Fe(III)/Fe(II) reaction were present in an unheat‐treated sample and in the sample heat‐treated at 200°C but were significantly reduced in height for the sample heat‐treated at 400°C. At higher temperatures they disappeared, indicating decomposition of FeTMPP‐Cl. After heat‐treatment at 700°C or higher, an anodic peak in the first cathodic sweep was observed and it was attributed to the dissolution of metallic Fe. XPS measurements did not show unambiguously the valence state of the Fe in the electrocatalyst heat‐treated at high temperatures, but comparison of cyclic voltammograms of electrodeposited Fe and a bulk Fe electrode with cyclic voltammograms of FeTMPP‐Cl/BP indicated that it was metallic Fe. Fe particles were observed on TEM images. Ma.ny more iron particles were present in the sample heat‐treated at 1000°C than in the sample heat‐treated at 800°C. Some of the particles remained in both samples after electrochemical dissolution, and they were completely surrounded by carbon particles or wrapped in the graphite shell. A well‐defined graphite shell surrounding iron particles was observed only in the sample heat‐treated at 1000°C.

The kinetics of O{sub 2} reduction on both oxidized and reduced Pt rotating disk surfaces covered with thin films (1 to 15 {micro}m) of recast polybenzimidazole (PBI) or Nafion have been examined in 0.1 M aqueous solutions of H{sub 3}PO{sub 4}, H{sub 2}SO{sub 4}, and HClO{sub 4} at 25.0 C. Polymer films were deposited on a Pt disk electrode by a spin-coating technique. Experiments were performed at different rotation rates and potential scan rates. This investigation was undertaken to establish to what extent the solid polymer electrolyte influences the mechanism and kinetics of O{sub 2} reduction. The number of electrons exchanged per O{sub 2} molecule and kinetic parameters for O{sub 2} reduction (reaction order with respect to O{sub 2}, Tafel slope/transfer coefficient, and exchange current density) are not changed in the presence of the polymer films, indicating that the reaction path and kinetics are not altered in the presence of recast PBI and Nafion films. The diffusion coefficient (D) and concentration (C) of O{sub 2} in recast films were determined by means of linear sweep voltammetry measurements in quiescent solution. The D and C values in polymer films immersed in acidic solutions were found to have different values than thosemore » in the solutions. D(O{sub 2}) is about 2.5 times lower in the recast films than in the solutions, whereas C(O{sub 2}) is slightly higher in the film. The largest concentration increase, by a factor of two, was found in PBI film in 0.1 M HClO{sub 4}. Cyclic voltammetric measurements under argon atmosphere have shown that PBI and Nafion recast films are electrochemically stable in the potential range between the onsets of H{sub 2} and O{sub 2} evolution. A decrease in the effective electrocatalyst surface area due to deposition of solid polymer films was 15 to 20%.« less

The scattering properties of four-parameter one-dimensional point interactions also define time aspect of these interactions. In this paper we investigate how different families of point interactions affect the relevant tunneling times. Particular emphasis is given to various interpretations of so called δ' potential.

The kinetics of O 2 reduction has been examined on an ink-type electrode made with Pt supported on high-area carbon. Electrocatalysts with 5-40 mass % of Pt on Black Pearls, Vulcan XC-72, and Shawinigan acetylene black carbons were used. Experiments were performed in 0.1 M solutions of H 2 SO 4 , H 3 PO 4 , HClO 4 , and NaOH. Kinetic parameters of O 2 reduction were found to be similar as on a smooth Pt surface. No influence of the type of carbon was observed. The mass activity of O 2 reduction was independent of Pt loading at low currents, but at high currents the mass activity decreased with an increase in Pt loading. It is suggested that mass-transfer limitations are responsible for the different influence of Pt loading on mass activity at low an high currents. Reproducibility of the measurements on the ink electrode was satisfactory, and it is recommended for investigations of dispersed electrocatalysts.

In this paper, we investigate phase rigidity of one-dimensional point interactions. With the aid of supersymmetric quantum mechanics (SUSYQM) we generate family of isospectral potentials describing point interactions. We than demonstrate that for SUSYQM generated bound states in the continuum (BIC) phase rigidity is always zero, while for bound states from discrete part of spectrum phase rigidity may vary from zero to unity, depending on the strength of point interaction.

Four-parameter family of point interactions represent all possible self-adjoint extensions of kinetic energy operator. We demonstrate a method for generating a bound state in the continuum of point interactions which relies on supersymmetric quantum mechanics (SUSYQM). Both zero and nonzero transparency cases are considered.

Hypertension was induced by chronic foot-shock and noise stress in adult male Sprague-Dawley rats. Microinjection of 0.3 microliters (150 mmol) sodium glutamate (Glu) into the nucleus arcuatus (ARC) elicited a significant depressor effect in rats with chronic stress-induced hypertension. The depressor effect induced by excitation of ARC neurons was attenuated significantly by microinjection of 0.3 microliters beta-endorphin antiserum (beta-EPAS) into the dorso-medial periaqueductal gray (PAG) or 0.1 microliters into the area of locus coeruleus (LC) due to blockage of beta-endorphinergic fibres from ARC to PAG or LC.

Es wird eine neue Methode zur schnellen elektroanalytischen Bestimmung des Antimons angegeben. Diese Methode gestattet die Bestimmung: 1.groser und kleiner Mengen metallischen Antimons 2.des Antimons in seinen Salzen und Erzen Vergleiche mit der titrimetrischen Methode mit Hilfe von Kaliumbromat ergaben gute Ubereinstimmung.