Resuscitation and quantification of stressed Escherichia coli K12 NCTC8797 in water samples

The aim of this study was to investigate the impact on numbers of using different media for the enumeration of Escherichia coli subjected to stress, and to evaluate the use of different resuscitation methods on bacterial numbers. E. coli was subjected to heat stress by exposure to 55 °C for 1 h or to light-induced oxidative stress by exposure to artificial light for up to 8 h in the presence of methylene blue. In both cases, the bacterial counts on selective media were below the limits of detection whereas on non-selective media colonies were still produced. After resuscitation in non-selective media, using a multi-well MPN resuscitation method or resuscitation on membrane filters, the bacterial counts on selective media matched those on non-selective media. Heat and light stress can affect the ability of E. coli to grow on selective media essential for the enumeration as indicator bacteria. A resuscitation method is essential for the recovery of these stressed bacteria in order to avoid underestimation of indicator bacteria numbers in water. There was no difference in resuscitation efficiency using the membrane filter and multi-well MPN methods. This study emphasises the need to use a resuscitation method if the numbers of indicator bacteria in water samples are not to be underestimated. False-negative results in the analysis of drinking water or natural bathing waters could have profound health effects

Analysis of a bonded connector for pultruded G.R.P. structural elements

Available from British Library Document Supply Centre-DSC:DXN039942 / BLDSC - British Library Document Supply CentreSIGLEGBUnited Kingdo

Synthesis, characterization and catalytic investigation of novel polymeric thiourea

In this study, in order to obtain polymeric thiourea compounds which have unsolubulity properties and higher metal content, new reaction pathways based on the use of the template effect were investigated. For this purpose, the reactions between different diamines, such as ethylendiamine, ortho (o-) and para (p-) phenylenediamine, and carbon disulfide (CS2) were investigated and optimized by using the template effect of Ni(II). Catalytic activity of the polymeric structure on oxidation of styrene was also investigated in terms of different parameters such as heat (25 and 80° C), time (4 and 8 h), oxidant hydrogen peroxide (H2O2), tert-butyl hydroperoxide (TBHP), di-tert-butyl peroxide (DtBP) and solvent (acetonitrile and benzene). The products have been characterized on the basis of analytical and spectral method, Fourier transform infrared spectroscopy, 1H- and 13C-nuclear magnetic resonance, gel-permeation chromatography, elemental analysis, thermogravimetric analysis, atomic adsorbtion spectrometry, gas chromatography and gas chromatography mass spectrometry. © 2010 Koninklijke Brill NV, Leiden.National Council for Scientific Research: 106 T 365The authors thank The Scientific and Tecnological Research Council (TÜB'TAK) for financial support (Project number 106 T 365) and Prof. Dr. Osman Serindag for the TGA/DTA analysis

Mild conditions for oxidation/epoxidation of styrene

In this study, in order to obtain novel support materials for immobilization of transition metals, polymeric Schiff bases were synthesized using a poly-condensation reaction between ortho(o-)phthalaldehyde tere(t-)phthalaldehyde, oxaldehyde and diamines like, e.g., ethylene-p- phenylene- and o-phenylenediamine. Additionally, catalytic activity of polymeric Schiff base metal on oxidation/epoxidation of styrene complexes were investigated. The products have been characterized on the basis of analytical and spectral method, Fourier transform infrared spectroscopy, 1H- and 13C-nuclear magnetic resonance, gel-permeation chromatography, elemental analysis, thermogravimetric analysis, atomic adsorbtion spectrometry, gas chromatography and gas chromatography mass spectrometry. © 2011 Koninklijke Brill NV, Leiden

Design of a short tensile coupon for fiber reinforced plastic using artificial neural networks

The measurement of the mechanical properties of Fibre Reinforced Plastic (FRP) material is necessary for numerical structural analysis and design. The mechanical properties of the FRP materials may be determined by specific coupon test methods or by analytical calculation. However, pultruded or moulded FRP components may not possess the dimensions to permit the extraction of standard length coupons. The shape of the short tensile coupon has been established to circumvent this limitation using a Finite Element (FE) representation and Artificial Neural Network (ANN) including the effect of gripping length, coupon shape, width, length and thickness. The FE results have been used for the learning and testing sets of the ANN. The Multi-Layer Perceptron (MLP) has been employed in the modelling of the ANN. The MLP model has been trained using the Scaled Conjugate Gradient Algorithm (SCGA) and tested. The ANN results show that the correlation between targets and outputs are consistent

The Relation between Uniaxial Compressive Strength and Block Punch Index for Pyroclastic Rocks

24th INTERNATIONAL MINING CONGRESS OF TURKEY -- APR 14-17, 2015 -- Antalya, TURKEYWOS: 000380558200080Because preparing the desired smooth specimens from pyroclastic rocks is difficult for some standard tests, the development of some equations is important for predicting the uniaxial compressive strength (UCS) of these rocks. In this study, the relation between the UCS and block punch index (BPI) for pyroclastic rocks was investigated. Twenty eight different samples of pyroclastic rocks collected from the Cappadocia Region were tested in the laboratory. The linear regression analysis shows that the UCS-BPI conversion factor for the tested rocks is 3.0. On the other hand, the correlation coefficient of power law function is higher than that of the linear function. Concluding remark is that the UCS-BPI conversion factor for the pyroclastic rocks is lower than the suggested general conversion factor of 5.5 and the UCS-BPI relation is best represented by power law function.UCTEA Chamber Min Enigneers Turke

Experimental and FE studies on the bonding performance of basalt FRP bonded to notched concrete beams and improving with anchorage

Fiber Reinforced Polymer (FRP) composites have been widely used for the repair and strengthening of the reinforced concrete (RC) structures. One of the main problems encountered in these methods is premature debonding failure of externally bonded FRP strip before reaching the strength capacity. In this study, experimental and finite element (FE) studies have been performed to investigate and improve the bonding performance of FRP strips externally bonded to the notched concrete beam surface. Parameters investigated through the experimental studies are (a) bond length, (c) concrete surface quality, (c) BFRP fan anchor, (d) BFRP U wrap anchor, and (e) a new steel anchor type; and that of numerical studies are (a) bond length, (b) concrete surface quality, and (c) a new steel anchor type. Specimens were tested by four-point flexural test under monotonic loading. The change of crack load, ultimate load, deflections, and failure modes were investigated by the results of the experiment and FE analysis. Then, Parametric studies were performed to determine an effective bond length, an efficient thickness of BFRP strips and an effective steel anchor location. According to the findings from the experimental and FE model study, the debonding failure of the non-anchored specimens is caused by the separation of a few millimeter-thick concrete layers from the concrete surface to which the FRP strips are adhered. The results of the experimental study showed that joining the ends of the BFRP strips with steel anchors increased the load-bearing capacity by 24–26% compared to UW and Fan anchors and by 29–43% compared to non-anchored samples; the developed FE model also confirmed these results. In order to effectively utilize the strength capacity of the BFRP strip, anchoring the end of the strip and evenly distributing the load on the BFRP strip proved to be more effective than solely extending the adhesive length