Polymers of intrinsic microporosity as high temperature templates for the formation of nanofibrous oxides

The highly rigid molecular structure of Polymers of Intrinsic Microporosity (PIM) – associated with a high thermolysis threshold – combined with the possibility to fill intrinsic micropores allows the direct “one-step” templated conversion of metal nitrates into nano-structured metal oxides. This is demonstrated here with PIM-EA-TB and with PIM-1 for the conversion of Pr(NO3)3 to Pr6O1

Health Status of Sand Flathead (Platycephalus bassensis), Inhabiting an Industrialised and Urbanised Embayment, Port Phillip Bay, Victoria as Measured by Biomarkers of Exposure and Effects

Port Phillip Bay, Australia, is a large semi-closed bay with over four million people living in its catchment basin. The Bay receives waters from the Yarra River which drains the city of Melbourne, as well as receiving the discharges of sewage treatment plants and petrochemical and agricultural chemicals. A 1999 study demonstrated that fish inhabiting Port Phillip Bay showed signs of effects related to pollutant exposure despite pollution management practices having been implemented for over a decade. To assess the current health status of the fish inhabiting the Bay, a follow up survey was conducted in 2015. A suite of biomarkers of exposure and effects were measured to determine the health status of Port Phillip Bay sand flathead (Platycephalus bassensis), namely ethoxyresorufin-O-deethylase (EROD) activity, polycyclic aromatic hydrocarbons (PAH) biliary metabolites, carboxylesterase activity (CbE) and DNA damage (8-oxo-dG). The reduction in EROD activity in the present study suggests a decline in the presence of EROD activity-inducing chemicals within the Bay since the 1990s. Fish collected in the most industrialised/urbanised sites did not display higher PAH metabolite levels than those in less developed areas of the Bay. Ratios of PAH biliary metabolite types were used to indicate PAH contaminant origin. Ratios indicated fish collected at Corio Bay and Hobsons Bay were subjected to increased low molecular weight hydrocarbons of petrogenic origin, likely attributed to the close proximity of these sites to oil refineries, compared to PAH biliary metabolites in fish from Geelong Arm and Mordialloc.Quantification of DNA damage indicated a localised effect of exposure to pollutants, with a 10-fold higher DNA damage level in fish sampled from the industrial site of Corio Bay relative to the less developed site of Sorrento. Overall, integration of biomarkers by multivariate analysis indicated that the health of fish collected in industrialised areas was compromised, with biologically significant biomarkers of effects (LSI, CF and DNA damage) discriminating between individuals collected in industrialised areas from observations made in fish collected in less developed areas of the Bay

Marine Tar Residues: a Review

Abstract Marine tar residues originate from natural and anthropogenic oil releases into the ocean environment and are formed after liquid petroleum is transformed by weathering, sedimentation, and other processes. Tar balls, tar mats, and tar patties are common examples of marine tar residues and can range in size from millimeters in diameter (tar balls) to several meters in length and width (tar mats). These residues can remain in the ocean envi-ronment indefinitely, decomposing or becoming buried in the sea floor. However, in many cases, they are transported ashore via currents and waves where they pose a concern to coastal recreation activities, the seafood industry and may have negative effects on wildlife. This review summarizes the current state of knowledge on marine tar residue formation, transport, degradation, and distribution. Methods of detection and removal of marine tar residues and their possible ecological effects are discussed, in addition to topics of marine tar research that warrant further investigation. Emphasis is placed on ben-thic tar residues, with a focus on the remnants of the Deepwater Horizon oil spill in particular, which are still affecting the northern Gulf of Mexico shores years after the leaking submarine well was capped

The peritectoid formation and mechanical properties of Zr[subscript 3]Al-based alloys

Imperial Users onl

Microstructure and thermal stability of electrodeposited nanocrystalline nickel

Nanocrystalline nickel deposits have been prepared using electrodeposition in nickel sulphate based baths. The samples were characterised using microhardness testing, X-ray diffraction (XRD) and transmission electron microscopy (TEM).As-deposited samples showed a narrow grain size distribution with an average grain size of less than 20nm. The greatly increased microhardness of nanocrystalline materials, similar to 500kg/mm(2) for the Ni samples in this study, and their other superior properties have many potential applications. However, the microstructure of nanocrystals is metastable, and grain growth occuring at elevated temperatures can lead to a deterioration of properties.In this work, we have studied grain growth in nanocrystalline Ni annealed at 250degreesC. TEM micrographs revealed that the type of growth is abnormal. 3D atom probe analysis gave no indication of gain boundary segregation in as-deposited materials, and the low levels of segregation found in material annealed for 60 minutes were clearly not sufficient to significantly inhibit grain growth.Upon annealing, an increase in hardness up to about 580kg/mm(2) occurred within the first 5 minutes. Despite fast abnormal grain growth inside the nanocrystalline Ni, the high hardness values were maintained for a surprisingly long time. Only after about 240 minutes when the volume fraction of abnormal grains was above 50%, did the hardness start to decrease significantly. A two-phase model is proposed to relate the hardness data to the observed microstructure