Cultivar and Maturity Effects on Muskmelon ( Cucumis melo) Colour,Texture and Cell Wall Polysaccharide Composition

Cell wall polysaccharides (CWP) of two types of melons were isolated and purified. Fractionations were performed using cyclohexanetrans-1,2-diamine tetraacetate (CDTA), Na₂CO₃, guanidinium thiocyanate (GTC) and KOH. Alditol acetate derivatives of neutral sugars from each CWP fraction were prepared and analysed by gas chromatography. Trifluoro-acetic acid insoluble fractions were analysed colorimetrically and uronic acid was determined. The CDTA and Na₂CO₃ fractions were found to be composed of typical pectic materialscontaining primarily galacturonic acid with the neutral sugars arabinose, galactose, rhamnose and a smaller amount of xylose. As maturity increased, CDTA fraction yields increased, though total neutral sugar CWP compositions decreased. GTC and KOH fractions were typical of hemicellulose, and contained principally xylose, glucose, galactose, mannose and fucose, with very small amounts of uronic acid, arabinose and rhamnose. The residues contained principally glucose and galactose, with smaller amounts of mannose, xylose, arabinose and fucose. With the exception of xylose and glucose, all neutral sugars decreased significantly during ripening in both the Cantaloupe and Honey Dew melons. Total uronic acid did not change as maturity increased, except for Cantaloupe, where total uronic acid decreased from the ripe to overripe stages. Relationships between firmness, drip loss and other composition measurements, as well as the total CWP sugar composition, were also determined. Only the CDTA fraction yields were negatively correlated with the changes in firmness of both melons and positively correlated with changes in drip loss as maturity increased.     

Spatial variation of residual stresses in a welded pipe for high temperature applications

Measurements of residual macro-stresses have been undertaken in a feature multipass circumferential single V butt-weld made from a P91 ferritic steel pipe over different spatial depths: (i) ≤10 μm by X-ray diffraction, (ii) ≤1 mm by incremental centre-hole drilling and (iii) through wall section using deep-hole drilling. The ability to make near-surface X-ray residual stress measurements on as-oxidised surfaces has been demonstrated and the implications for use in the evaluation of overall integrity are discussed. Each of the three measurement techniques provides complementary and consistent measurement of induced residual stresses for weld metal, heat affected zone and parent metal for the as-welded and the post-weld heat-treated conditions over the complete spatial range. The results are discussed with respect to the importance of the weld capping run in introducing near-surface compressive residual stresses, the through-wall profiles of the residual stresses measured at the weld metal position in hoop and axial directions and the presence of existing surface oxide.     

Benchmarking parameters for remote electrochemical corrosion detection and monitoring of offshore wind turbine structures

The remote location and position of offshore wind turbine structures severely limits the application of in situ corrosion detection methods such as ultrasonic, acoustic emission, and X‐ray. A real‐time remote sensing (RTRS) technology can be implemented to provide autonomous detection and monitoring, providing exhaustive and detailed information on the corrosion process. Utilizing the concept of Internet of Things (IoT) through the integration with satellite and terrestrial communication network, iWindCr, a technology development project funded by the Innovate UK, aims to design a wireless sensor network (WSN) of smart miniaturized sensors for corrosion detection and monitoring of the offshore wind turbine structures. This paper discusses the rationale and challenges around the iWindCr WSN design, particularly in the development of a miniaturized system and in relation to the provision of power and power consumption. The later has led to the selection and the integration of the electrochemical analysis techniques, namely open circuit potential (OCP) and zero resistance ammeter (ZRA) on the sensor interface system. The verification of these techniques for the corrosion detection sensor has resulted in a database consisting of the corrosion parameter outputs or threshold values of metals specific to offshore wind turbine structures, in this case tower, foundation, and nacelle (gearbox). The database provides end‐users with the benchmark that can be used to detect physical changes during the course of corrosion or passive film damage. These parameters are incorporated in the user interface data analytic software, enabling the quantification of corrosion or film damage.