Search

• The addition of MgAlCO 3 -LDHs to the IFR coating effectively reduced the TSP and SPR from the cone calorimetry. • Thermal decomposition of MgAlCO3-LDHs could promote and catalyze esterification between APP and PER. • The C-N-P-MgAl coating could improve the thermal insulation performance of the char layer. MgAlCO 3 -layered double hydroxides (MgAlCO 3 -LDHs) were introduced in a waterborne intumescent fire retardant (IFR) with nano-coating containing ammonium polyphosphate (APP), pentaerythritol (PER), and melamine (MEL). The effects of MgAlCO 3 -LDHs were evaluated based on thermogravimetry (TG), differential thermal analysis (DTA), Fourier transform infrared spectroscopic analyses (FT-IR), X-ray power spectroscopy (XPS), scanning electron microscopy (SEM), fire performance test, and cone calorimetry. The 1.8 wt% of MgAlCO 3 -LDHs added to the IFR coating promoted the expansion of the char layer to improve its thermal insulation performance during the fire performance test. The results characterized by TG, DTA, XPS, and FT-IR revealed that MgAlCO 3 -LDHs enhanced the residual weight, the thermal stability and the oxidation resistance of the IFR coating. There was statistical evidence that the heat-shielding performance was reinforced by adding an appropriate amount of MgAlCO 3 -LDHs to the IFR coating to form uniform and compact foams in the char layer by using the digital image to process SEM images. The cone calorimetry revealed that a 46% reduction in total smoke production (or total smoke release) and a 25% decrease in the smoke production ratio were achieved in the coating with added MgAlCO 3 -LDHs compared with that without. It can be concluded that the addition of MgAlCO 3 -LDHs to IFR coating actively interacts with APP, PER, and MEL, thus improving the fire retardant properties of the coating. [ABSTRACT FROM AUTHOR]

BACKGROUND Biocontrol is a promising strategy in the control of rice blast disease. In the present study, we isolated and characterized a novel antagonist to the pathogen Magnaporthe oryzae from rice endophytic actinomycetes. RESULTS Out of 482 endophytic actinomycetes isolated from rice blast infected and healthy rice, Streptomyces endus OsiSh-2 exhibited remarkable in vitro antagonistic activity. Scanning electron microscopy observations of M. oryzae treated by OsiSh-2 revealed significant morphological alterations in hyphae. In 2-year field tests, the spraying of OsiSh-2 spore solution (107 spores mL−1) is capable of reducing rice blast disease severity by 59.64%. In addition, a fermentation broth of OsiSh-2 and its cell-free filtrates could inhibit the growth of M. oryzae, suggesting the presence of active enzymes and secondary metabolites. OsiSh-2 tested positive for polyketide synthase-I and nonribosomal peptide synthetase genes and can produce cellulase, protease, gelatinase, siderophore, indole-3-acetic acid and 1-amino-cyclopropane-1-carboxylate deaminase. A preliminary separation indicated that the methanol extract of OsiSh-2 could suppress the growth of pathogens. The major active component was identified as nigericin. CONCLUSION Endophytic S. endus OsiSh-2 has potential as a biocontrol agent against rice blast in agriculture. © 2016 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In this work, nanostructured copper oxide of varied morphologies and high surface area were prepared by calcination of copper oxalate precursors, and were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, thermogravimetric analysis and differential thermal analysis, and nitrogen adsorption–desorption measurements. The sphere-like CuO (specific surface area: 73 m2 g−1) functionalized QCM resonators were fabricated and explored for HCN sensing. The sensitivity (10 s HCN exposure) of sphere-like CuO functionalized QCM resonators reached as high as 6.53 Hz μg−1. The reproducibility and stability of sphere-like CuO functionalized QCM resonators was excellent, and the selectivity was very high with a converse response to examined common chemicals. The high surface area CuO functionalized QCM sensors may be applicable for HCN gas sensing. [ABSTRACT FROM AUTHOR]

• An analysis method for SEM images of intumescent fire retardant char layers is proposed. • Foams in an intumescent fire retardant char layer are characterized quantificationally. • Appropriate addition of CaAlCO 3 -LDHs makes the char layer compact and uniform. • Unsatisfactory result image after color transformation is returned to object segmentation. A new characterization method is proposed to investigate the microscopic morphology of intumescent fire retardant (IFR) char layer observed under a scanning electron microscope (SEM). The method consists of object segmentation extracting the object, color transformation improving the recognition of subtle details, and statistical analysis obtaining the features (area, average, and standard deviation) of the object in the SEM images. There is a descending trend in the standard deviation of the foams with the increase of CaAlCO 3 -LDHs (layered double hydroxides) added to the coatings. Specifically, the number of the foams in the IFR coating with 5 wt% of CaAlCO 3 -LDHs addition is increased from 102 (that of the char layer without CaAlCO 3 -LDHs) to 123. Meanwhile, the standard deviation of the foams in the char layer is decreased from 6383.6 to 4304.5, demonstrating that an appropriate addition of CaAlCO 3 -LDHs can improve the foam quality of the IFR coating by making it more compact and uniform, and enhance the thermal insulation of the char layer covered on the substrate surface. [ABSTRACT FROM AUTHOR]

Abstract: In the current work, CuO nanoparticles were synthesized in a facile way, and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetry. Using these CuO nanoparticles, CuO functionalized QCM resonators were fabricated and explored for HCN sensing. The sensing properties were studied by a sensor characterization system coupled with a mass spectrometer. The sensor response to HCN (+347Hz) was found to be in an opposite direction as compared with other common volatile substances (ether: −1230Hz; water: −1815Hz; n-hexane: −2100Hz; benzene: −3410Hz; acetic acid: −4840Hz; ethanol: −6270Hz), offering excellent selectivity for HCN detection. In addition, the sensitivity (15.1Hz/μg) was very high, and the response (30s) and recovery (750s) were very fast. A sensing mechanism was proposed based on experimental results, in which a surface redox reaction occurs between CuO and Cu2O on the nanoparticle reversibly upon contact with HCN and air, respectively. The current results would provide an exciting alternative to fast, sensitive and selective detection of trace HCN, which would be of particular benefit in the area of public security and environmental applications. [Copyright &y& Elsevier]

Copper oxide nanoparticles were prepared by the solvothermal method, and characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and nitrogen adsorption-desorption measurements. The as-prepared CuO nanoparticles functionalized QCM resonators were fabricated and explored for HCN sensing under varied humidity conditions. When the humidity of air containing HCN is the same as that of environmental air, a characteristic positive frequency shift of CuO nanoparticles functionalized QCM resonator is always observed towards HCN because of a reversible surface redox reaction between CuO and HCN. The sensitivity of CuO nanoparticles functionalized QCM resonators increases with increase of relative humidity in the range of 9-51%. These results provide an important guidance for further developing HCN gas sensors towards practical applications. [ABSTRACT FROM AUTHOR]