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Wellington, New Zealand

Cottle D.J.,University of New England of Australia | Baxter B.P.,SGS New Zealand Ltd.
Textile Progress | Year: 2015

This review explores research and development in wool metrology to date. In doing so, it highlights the research work undertaken by three organisations, in particular, to the development of wool and textile metrology research covering all of the important physical properties of wool. Three key wool research centres at the beginning of the twenty-first century were CSIRO's Division of Textile and Fibre Technology at Belmont near Geelong, Victoria, the School of Fibre Science and Technology, University of NSW at Kensington, NSW in Australia, and the Wool Research Organisation of New Zealand Inc. at Lincoln near Christchurch, New Zealand. Due to funding pressures between 1997 and 2007, these centres either ceased to operate or were absorbed into larger, non-wool-focused organisations. The substantial contribution to the world's wool metrology literature made by their staff and graduates, over the period when the three organisations had around 300-500 staff involved in wool-related research activities, is recognised. The review analyses the research undertaken on wool properties to identify gaps that might be exploited through the application of new or novel use of technologies by the next generation of wool metrologists. The analysis indicates that although the main fibre/fleece characteristics which currently affect the pricing and trading of Merino wool are able to be readily and accurately measured, there remains considerable work to be done in linking wool measurements to the prediction of performance both in processing and in the final product. © 2015 The Textile Institute. Source

Liu W.,SGS New Zealand Ltd.
Engineering Failure Analysis | Year: 2013

The premature failure of the economiser in a biomass fuel boiler was studied. On the internal oxide surface, three morphologies of iron oxides - aggregate oxide (Fe3O4), flower oxide (Fe3O4) and spherical oxide (FeO) have been discovered using ESEM/EDS. The oxidation and pitting occurred on the internal surface was trivial in comparison to the erosion-corrosion rate at outer surface of the economiser. The dominant abrasive SiO2 particles were partially cemented by the calcium compound particles in the biomass fly ash. The individual sharp abrasive SiO2 particles had been revealed with filtergram by dissolved the calcium compound particles in acid solution. The average size of SiO2 particles was approximately 100μm. Some SiO2 particles were up to 500μm. Study on the external scale found different oxide morphologies and the compositions, the flower-like oxide (Fe3O4) at the top and " mud-crack" FeO oxide at the flat sides. The wastage profile of 'V-shaped thickness thinning' can be explained by the mechanism proposed in this paper; the oxidation acting simultaneously with two-body abrasive wear by fly ash particle impingement. © 2013 Elsevier Ltd. Source

Liu W.,SGS New Zealand Ltd.
Advanced Materials Research | Year: 2014

A repeat geartooth breakage occurred in a load gearbox of a 40MW steam turbine. Fractographic examination suggests that the breakage was a fatigue fracture. The oil deposit on the fracture surface has been applied as an auxiliary fractographic method. The root cause of the failure was due to improper heat treatment. The insufficient surface hardness and shallow case caused the case/core separation. The very coarse low carbon martensite in core caused cleavage fracture in final fast fracture. The fractographic morphology of the butterfly has been revealed. Hertzian stress and non-metallic inclusions are not the necessary condition of the butterfly formation. The microcracks within the butterflies did not actively play the role of the fatigue rupture. © (2014) Trans Tech Publications, Switzerland. Source

Liu W.,SGS New Zealand Ltd.
Engineering Failure Analysis | Year: 2014

Bearing premature failures are prevalent in VFD (Variable Frequency Drives) motors. The three common symptoms of the modern bearing current appeared on the bearings of a group of pump motors. The bearing failure mechanisms have been studied from the tribological point of view. The natures of the three common symptoms have been uncovered. A hypothesis of the skin effect has been proposed to explain the three common symptoms. The discovery of the serial microcraters reveals the discharge with Fourier series features. The nature of the fluting patterns excluded the theories of both EDM (Electrical Discharge Machining) and discharge corrugation. VA (Vibration Analysis) detected the harmonics of the BPOR (Ball Pass Outer Ring) frequency which associated with the fluting on the outer raceway. This discovery may be applied to detect fluting in condition monitoring. © 2014 Elsevier Ltd. Source

Liu W.,SGS New Zealand Ltd.
Engineering Failure Analysis | Year: 2014

A duplex stainless steel (2205) pipe in a new yacht suffered an extremely high corrosion rate (40mm/y) failure. ESEM/EDS and XPS analyses indicate that the failure mode was MIC. The bacteria attached preferentially on the austenite grains forming the colony "centre". The preferential corrosion on the austenite grains formed the "sponge" feature. The remaining ferrite grains became the "skeleton" structure. The sulphate detected by XPS suggests SOB involvement in the MIC. A hypothesis of SRB and SOB proliferating symbiotically proposed in this paper can explain the extremely high corrosion rate. SRB transferred sulphate from seawater to sulphide. SOB converted the sulphide to the extremely acid (H2SO4). SOB should be the main culprit of the failure through its high corrosion rate. The nitriding effect around the FZ had been confirmed by SES and EDS analyses. The high nitrogen contents attracted the bacteria to attach and proliferate. This finding may uncover the mystery of why weldments are susceptible to MIC. © 2014 Elsevier Ltd. Source

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