RRS James Cook Cruise JC120 15 Apr - 19 May 2015. Manzanillo to Manzanillo, Mexico. Managing Impacts of Deep-seA resource exploitation (MIDAS): Clarion-Clipperton Zone North Eastern Area of Particular Environmental Interest

RRS James Cook Cruise JC120 was part of the Managing Impacts of Deep-seA resource exploitation (MIDAS) European Union Framework Programme 7 Project. It was jointly funded by the UK Natural Environment Research Council. JC120 was the first UK science cruise to the Clarion Clipperton Zone (CCZ) in the northern equatorial Pacific, an area likely to be targeted for deep-sea mining for polymetallic nodules. This cruise visited the north easternmost Area of Particular Environmental Importance (APEI). There are a total of nine of these APEIs situated to the north and south of the mining claim areas defined by the International Seabed Authority (ISA) across the CCZ. The APEIs have been delineated by the ISA as part of their environmental management plan for the CCZ and are designed to protect representative species and habitats for the CCZ. The APEIs have been designed based on surface ocean characteristics and the topography of the seafloor, estimated from satellite altimetry. At present there has been virtually no sampling of seafloor habitats or species in the APEIs. The NERC cruise aimed to change that. The cruise studied a representative area of the APEI in great detail at high resolution and over a variety of scales. This characterised the habitats, biology, physical and chemical conditions - adding important information about the CCZ in general and making a detailed baseline assessment for this area, which can be compared to other sites and used as a barometer of change in the deep sea associated with mining activities. The NERC cruise JC120 used a variety of tools for assessment of this >4000m deep area of the CCZ. Shipboard mapping of depth and backscatter were carried out (EM12). The autonomous underwater vehicle (AUV) Autosub6000 carried out wide-area acoustic surveys (Edgetech Side-scan sonar, EM2040 Multibeam Bathymetry and sub-bottom profiler), collected seabed photographs and made physical measurements of the water column of the APEI. There were also more detailed HD video and photographic surveys of the seafloor using the HyBIS vehicle. Sediment samples (megacore, boxcore and gravity core), water samples (CTD) and biological samples (Agassiz Trawl) were also collected

Characterisation of microstructure, defect and high-cycle-fatigue behaviour in a stainless steel joint processed by brazing

We report the characterisation of microstructures and high-cycle-fatigue (HCF) properties of Type 304 stainless steel joints processed by brazing. Pure copper was applied as the filler metal for brazing at 1120 °C. A two-phase microstructure was obtained within the joint region: the star-shaped precipitates and copper matrix. The precipitates with an average size of 0.43 μm were rich in iron and chromium. A fixed orientation relationship was found between the precipitates and copper matrix. The joint exhibited much higher tensile strength and HCF life when compared to pure copper. The strength enhancement can be attributed to the presence of precipitates. Furthermore, the effect of joint interface roughness as well as defects was critically investigated. The joint interface roughness showed little influence on the HCF lives. Post-examinations revealed that fatigue crack initiation and propagation occurred entirely within the joint region, hence being consistent with the similar HCF lives regardless of the pre-defined interface roughness conditions. In addition, it was found that the HCF lives decreased exponentially with the increase of initial defect area. Fractography analysis revealed that fatigue striation spacings near the crack initiation zone increased with the increase of defect area, suggesting that the larger defects result in higher crack growth rate, hence shorten the overall fatigue life.</div

Weird weather in Bristol during the Grindelwald Fluctuation (1560–1630)

The Grindelwald Fluctuation (1560–1630) was a cooling phase during the ‘Little Ice Age’ (c.1300–1850). Poor weather during the Fluctuation contributed to harvest failures, mass starvation and political crises across the globe. This paper examines information taken from Bristol chronicles that discuss some of the extreme weather events of the period. The entries support the notion that the Grindelwald Fluctuation featured some extraordinarily poor weather, such as great frosts, floods, severe storms, unseasonal snowfalls and droughts