Advanced Materials Research Vols. 610-613

Abstract: The effect of hydrogen peroxide (H₂O₂) of low concentration on thermotolerance of tall fescue (Festuca arundinacea cv. Barlexas) and perennial ryegrass (Lolium perenne cv. Accent) was studied following a foliar pretreatment with 10 mM H₂O₂. Turfgrass quality, relative water content (RWC), oxidative damage were measured in both cool-season turfgrass cultivars under heat stress (38/30 °C, day/night) and control normal temperature (26/15 °C, day/night). Pre-treated plants of two cultivars showed the lower MDA and H₂O₂ levels and the higher turfgrass quality and RWC under heat stress. Our results demonstrated that exogenous H₂O₂ of the low concentration improved the thermotolerance of tall fescue and perennial ryegrass by inducing the antioxidative enzyme activities and alleviating the oxidative damage.

Abstract: Corrosion behavior of steel Q235 was investigated during natural evaporation in soils with and without sulfate reducing bacteria (SRB) by microbiological analysis, electrochemical impedance spectroscopy (EIS), energy dispersive X-ray analysis (EDXA) and electron-probe X-ray microanalysis (EPMA). The results show that during natural evaporation, oxygen content increases, amounts of SRB decrease, and the corrosion rates of steel Q235 increase with decreasing humidity of soils with and without SRB. Increments of the corrosion rates are much bigger in soils with SRB than those without SRB.

Abstract: The effect of hydrogen peroxide (H₂O₂) of low concentration on thermotolerance of tall fescue (Festuca arundinacea cv. Barlexas) and perennial ryegrass (Lolium perenne cv. Accent) was studied following a foliar pretreatment with 10 mM H₂O₂. Antioxidative enzymes activities and antioxidant content were measured in both cool-season turfgrass cultivars under heat stress (38/30 °C, day/night) and control normal temperature (26/15 °C, day/night). While activities of catalase(CAT), guaiacol peroxidase (POD), ascorbate peroxidase (APX), glutathione reductase (GR) and glutathione-dependent peroxidases (GPX) were enhanced by H₂O₂ pretreatment during heat stress. APX, GR and GPX activities were significantly enhanced during heat stress. These were likely the most important antioxidative enzymes in tall fescue and perennial ryegrass protecting plants against heat stress. The thermotolerance was also concomitant with an increased glutathione pool, as evaluated by the significant increase of the total glutathione pool in two pretreated cultivars. The increase of POD, CAT, APX, GR activities and significant increase of GPX activity prior to the initiation of heat stress in pre-treatment plants suggested a possible role for H₂O₂ as a signaling molecule protecting them against the subsequent heat-induced damage.

Abstract: The lignin will drag interference in the system of the sugar determination. Dual wavelength spectrophotometry can remove the interference when making use of the DNS to detect the reducing sugar content in the black liquor. After the analysis to the absorbency graphs of the lignin and the glucose dissolved in the DNS solution at specific wave length region in the ultraviolet-visible light, and the contrast between the coefficients of the relation curves between their absorbency and their concentration at specific wave length, the test wave length is intended to be 520 and 570nm. From the relation curves between the absorbency of the lignin and its concentration at 520nm and 570nm, the magnification coefficient of the differential signal were defined as K2=5.338, K1=3.288.The correction index k=1.2. Then the concentration c (g/L) of the glucose solution can be figured out through formula c=(S/k-0.0165)×M/0.821.Then a group of glucose solution with same glucose addition but different lignin addition had been measured. So this method is effective to detect the reducing sugar content in the black liquor.

Abstract: In this paper,granular activated carbon GAC was used to investigate the adsorption capacity and adsorption rate of a typical nitrogen-containing organic compounds L-phenylalanine. GAC shows a high adsorption capacity for the L-phenylalanine and the adsorption isotherms conform to with Langmuir model.The pseudo-first-order equation shows the best fitting for adsorption kinetics in L-phenylalanine adsorption by GAC. Besides the factors such as the temperature, adsorption time and activated carbon quantity were studied.

Abstract: Hydrogen-producing zymogenous bacteria YUAN-3 (Ethanoligenens harbinense) is used as the study object, on which the intermittent hydrogen production test is applied to examine the influence of Magnesium ions concentration on the growth and gas generation of YUAN-3. Research results show that when Magnesium ions concentration is 0.3g/L, volatile acid reaches the maximum level; when Magnesium ions concentration is maintained at 0.3g/L, the unit volume production of hydrogen reaches at 256mlH₂/L，culture medium is applicable for hydrogen generation of YUAN-3.

Abstract: A sensitive method for the simultaneous determination of TCC and TCS in water, which involves enrichment with SPE and detection with HPLC-ESI-MS, was developed. The influence of the operational parameters,such as eluan, the acidity of the sample, were investigated and optimized. Under the optimum conditions, the limits of detection were 1.0 ng L-1and 2.5 ng L-1 for TCC and TCS, respectively. The method was successfully applied to the analysis of triclocarban and triclosan in real environmental water samples, including river water, lake water and tap-water. The spiked recoveries of TCC and TCS in these samples were achieved in the range of 89.5%–97.5%.

Abstract: Splash zone corrosion was investigated for a number of selected corrosion resistant alloys including in synthetic seawater. Stainless steels 304 and 316 and duplex stainless steels 2205 and 2507 were all investigated. A laboratory apparatus designed to simulate the wetting by a splash, and the subsequent drying through exposure to the weather, was used for this study. The corrosion potential showed a distinct evolution throughout the wet – dry cycle, compared to a sample maintained under constant immersion. However, the corrosion potential gave no indication of susceptibility to pitting corrosion. On the other hand, examination under an infinite focus microscope revealed significant pitting in the samples subjected to wet – dry cycling compared to those maintained under constant immersion

Abstract: Crevice corrosion (CC) was investigated for a number of selected corrosion resistant alloys in natural seawater containing microorganisms for up to 18 months under stagnant conditions. Experimental controls consisted of tests in natural seawater filtered in accordance with hydrostatic testing procedures. The corrosion potential of alloys was monitored throughout exposure and corrosion was evaluated by weight loss and 3D optical microscopy. CC was initiated on several alloys and corrosion rates in time indicated a positive effect of seawater filtration on the long-term performance of the alloys. Microbial adhesion, as indicated by fluorescence microscopy, occurred mainly outside the crevice and differed according to the nature of the substratum surface.

Abstract: In order to understand the micro-interfacial relationship between environmental copper ions and loosely bound extracellular polymeric substances (LB-EPS), a fluorescence titration of LB-EPS from the Hongfeng lake sediment by Cu (Ⅱ) was studied. Results showed that Cu (Ⅱ) could debase the fluorescence intensity (FI) of LB-EPS. Titration of LB-EPS by Cu (Ⅱ) at pH values of 4.0, 6.0, 7.0 and 9.0 demonstrated an obvious variety of wavelength spectra. The FI of LB-EPS reacting with Cu (Ⅱ) (2.5×10-4M), with the increase of pH values, decreased, which was attributed to more conjunct capacity of the fluorophore with Cu (Ⅱ) in alkaline conditions. At low or middle pH, the quenching of LB-EPS by Cu (Ⅱ) was attributed to the complex quenching triggered by ligand processes; and in the high pH the cause of quenching was not only linked to complex quenching, but also related to collision quenching.