A Kind of Affine Weighted Moment Invariants

A new kind of geometric invariants is proposed in this paper, which is called affine weighted moment invariant (AWMI). By combination of local affine differential invariants and a framework of global integral, they can more effectively extract features of images and help to increase the number of low-order invariants and to decrease the calculating cost. The experimental results show that AWMIs have good stability and distinguishability and achieve better results in image retrieval than traditional moment invariants. An extension to 3D is straightforward

Phase Behavior during Electrochemical Cycling of Ni-Rich Cathode Materials for Li-Ion Batteries

Although layered lithium nickel-rich oxides have become the state-of-the-art cathode materials for lithium-ion batteries in EV applications, they can suffer from rapid performance failure – particularly when operated under conditions of stress (temperature, high voltage), the underlying mechanisms of which are not fully understood. In this essay, we aim to connect the electrochemical performance with changes in structure during cycling. First, we compare the structural properties of LiNiO2, to the substituted Ni-rich compounds NMCs (LiNixMnyCo1-x-yO2) and NCAs (LiNixCoyAl1-x-yO2). Particular emphasis is placed on decoupling intrinsic behaviour and extrinsic “two-phases” reactions observed during initial cycles, as well as after extensive cycling for NMC and NCA cathodes. We highlight the need to revisit the various high-voltage structural change processes that occur in LiNiO2 with modern characterization tools to aid the understanding of the accelerated degradation for Ni- rich cathodes at high voltages

Increased Dissolved Organic Carbon Concentrations in Peat‐Fed UK Water Supplies Under Future Climate and Sulfate Deposition Scenarios

Peatlands are globally‐important terrestrial carbon stores as well as regional sources of potable water supply. Water draining from peatlands is rich in dissolved organic carbon (DOC), which can be problematic for water treatment. However, it is unclear how future climate and sulfate deposition changes may impact DOC in peatland‐derived potable water. The United Kingdom (UK) is a global hotspot that consumes 79% of all potable water derived directly from peatlands. Here, a physically‐based hydrological model and a biogeochemical organic carbon model were used to predict discharge and DOC concentration in nine hotspots of peatland‐derived potable water use in the UK under a range of 21st century climate and sulfate deposition scenarios. These nine catchments supply 72% of all peatland‐derived water consumed in the UK and 57% of the global total, equivalent to the total domestic consumption of over 14 million people. Our simulations indicate that annual discharges will decrease and that mean annual DOC concentrations will increase under all future scenarios (by as much as 53.4% annually for the highest emissions scenario) in all catchments. Large increases (by as much as a factor of 1.6) in DOC concentration in the 2090s over the baseline period are projected for autumn and winter, seasons when DOC concentrations are already high in the baseline datasets such that water treatment works often reach their capacity to cope. The total DOC flux is largely insensitive to future climate change because the projected increase in DOC concentration is mostly counterbalanced by the projected decrease in discharge

Experimental assessment and constitutive modelling of rubberised concrete materials

This paper focuses on examining the uniaxial behaviour of concrete materials incorporating rubber particles, obtained from recycled end-of-life tyres, as a replacement for mineral aggregates. A detailed account of a set of material tests on rubberised concrete cylindrical samples, in which fine and coarse mineral aggregates are replaced in equal volumes by rubber particles with various sizes, is presented. The experimental results carried out in this investigation, combined with detailed examination of data available from previous tests on rubberised concrete materials, show that the rubber particles influence the mechanical properties as a function of the quantity and type of the mineral aggregates replaced. Experimental evaluation of the complete stress-strain response depicts reductions in compressive strength, elastic modulus, and crushing strain, with the change in rubber content. Enhancement is also observed in the energy released during crushing as well as in the lateral strain at crushing, primarily due to the intrinsic deformability of the interfacial clamping of rubber particles which leads to higher lateral dilation of the material. The test results and observations enable the definition of a series of expressions to estimate the mechanical properties of rubberised concrete materials. An analytical model is also proposed for the detailed assessment of the complete stress-strain response as a function of the volumetric rubber ratio. Validations performed against the material tests carried out in this study, as well as those from previous investigations on rubberised concrete materials, show that the proposed models offer reliable predictions of the mechanical properties including the full axial and lateral stress-strain response of concrete materials incorporating rubber particles

Dynamic shear fracture toughness and failure characteristics of Ti–6Al–4V alloy under high loading rates

A novel 2-bar/double-shear impact (2B/2SI) loading technique is used to study the dynamic mode II (shear) fracture characteristics of Ti–6Al–4V. The new specimen design, to be used in combination with a standard split Hopkinson pressure bar, circumvent classical limitations associated with conventional one-point impact methods. This paper presents a combined experimental-numerical approach to determining the mode II fracture toughness of Ti–6Al–4V for a broad range of loading rates between 1.10 × 10^{−2}- 4.98 × 10^{7} (MPa, m^{1/2}s^{−1}). Results showed only a slight initial increase in toughness, which increases abruptly with loading rates beyond 10^{6} (MPa, m^{1/2}s^{−1}). Fractographic examination showed distinctively different mechanisms in operation at the microscale, depending on the rate of loading. Failure is through a brittle-ductile, mixed-mode fracture under quasi-static conditions; by contrast, the fracture surface exhibited fractographic features of adiabatic shear bands (ASB) and material melting/re-solidification under dynamic conditions. High-speed photography showed that both dynamic shear fracture (DSF) and ASB occurred during the same loading process. Interactions between DSF and ASB were observed to influence the dominant failure mechanism of the material at high loading rates

A New Troodontid Theropod Dinosaur from the Lower Cretaceous of Utah

BACKGROUND: The theropod dinosaur family Troodontidae is known from the Upper Jurassic, Lower Cretaceous, and Upper Cretaceous of Asia and from the Upper Jurassic and Upper Cretaceous of North America. Before now no undisputed troodontids from North America have been reported from the Early Cretaceous. METHODOLOGY/PRINCIPAL FINDINGS: Herein we describe a theropod maxilla from the Lower Cretaceous Cedar Mountain Formation of Utah and perform a phylogenetic analysis to determine its phylogenetic position. The specimen is distinctive enough to assign to a new genus and species, Geminiraptor suarezarum. Phylogenetic analysis places G. suarezarum within Troodontidae in an unresolved polytomy with Mei, Byronosaurus, Sinornithoides, Sinusonasus, and Troodon+(Saurornithoides+Zanabazar). Geminiraptor suarezarum uniquely exhibits extreme pneumatic inflation of the maxilla internal to the antorbital fossa such that the anterior maxilla has a triangular cross-section. Unlike troodontids more closely related to Troodon, G. suarezarum exhibits bony septa between the dental alveoli and a promaxillary foramen that is visible in lateral view. CONCLUSIONS/SIGNIFICANCE: This is the first report of a North American troodontid from the Lower Cretaceous. It therefore contributes to a fuller understanding of troodontid biogeography through time. It also adds to the known dinosaurian fauna of the Cedar Mountain Formation

Long-term and seasonal changes in nutrients, phytoplankton biomass, and dissolved oxygen in deep bay, Hong Kong

Deep Bay is a semienclosed bay that receives sewage from Shenzhen, a fast-growing city in China. NH 4 is the main N component of the sewage (>50% of total N) in the inner bay, and a twofold increase in NH 4 and PO 4 concentrations is attributed to increased sewage loading over the 21-year period (1986-2006). During this time series, the maximum annual average NH 4 and PO 4 concentrations exceeded 500 and 39 μM, respectively. The inner bay (Stns DM1 and DM2) has a long residence time and very high nutrient loads and yet much lower phytoplankton biomass (chlorophyll (Chl) 2 mg L -1) than expected. Because it is shallow (̃2 m), phytoplankton growth is likely limited by light due to mixing and suspended sediments, as well as by ammonium toxicity, and biomass accumulation is reduced by grazing, which may reduce the occurrence of hypoxia. Since nutrients were not limiting in the inner bay, the significant long-term increase in Chl a (0. 52-0. 57 μg L -1 year -1) was attributed to climatic effects in which the significant increase in rainfall (11 mm year -1) decreased salinity, increased stratification, and improved water stability. The outer bay (DM3 to DM5) has a high flushing rate (0. 2 day -1), is deeper (3 to 5 m), and has summer stratification, yet there are few large algal blooms and hypoxic events since dilution by the Pearl River discharge in summer, and the invasion of coastal water in winter is likely greater than the phytoplankton growth rate. A significant long-term increase in NO 3 (0. 45-0. 94 μM year -1) occurred in the outer bay, but no increasing trend was observed for SiO 4 or PO 4, and these long-term trends in NO 3, PO 4, and SiO 4 in the outer bay agreed with those long-term trends in the Pearl River discharge. Dissolved inorganic nitrogen (DIN) has approximately doubled from 35-62 to 68-107 μM in the outer bay during the last two decades, and consequently DIN to PO 4 molar ratios have also increased over twofold since there was no change in PO 4. The rapid increase in salinity and DO and the decrease in nutrients and suspended solids from the inner to the outer bay suggest that the sewage effluent from the inner bay is rapidly diluted and appears to have a limited effect on the phytoplankton of the adjacent waters beyond Deep Bay. Therefore, physical processes play a key role in reducing the risk of algal blooms and hypoxic events in Deep Bay. © 2009 Coastal and Estuarine Research Federation.published_or_final_versionSpringer Open Choice, 01 Dec 201

Selective targeting of activating and inhibitory Smads by distinct WWP2 ubiquitin ligase isoforms differentially modulates TGFβ signalling and EMT

Ubiquitin-dependent mechanisms have emerged as essential regulatory elements controlling cellular levels of Smads and TGFß-dependent biological outputs such as epithelial–mesenchymal transition (EMT). In this study, we identify a HECT E3 ubiquitin ligase known as WWP2 (Full-length WWP2-FL), together with two WWP2 isoforms (N-terminal, WWP2-N; C-terminal WWP2-C), as novel Smad-binding partners. We show that WWP2-FL interacts exclusively with Smad2, Smad3 and Smad7 in the TGFß pathway. Interestingly, the WWP2-N isoform interacts with Smad2 and Smad3, whereas WWP2-C interacts only with Smad7. In addition, WWP2-FL and WWP2-C have a preference for Smad7 based on protein turnover and ubiquitination studies. Unexpectedly, we also find that WWP2-N, which lacks the HECT ubiquitin ligase domain, can also interact with WWP2-FL in a TGFß-regulated manner and activate endogenous WWP2 ubiquitin ligase activity causing degradation of unstimulated Smad2 and Smad3. Consistent with our protein interaction data, overexpression and knockdown approaches reveal that WWP2 isoforms differentially modulate TGFß-dependent transcription and EMT. Finally, we show that selective disruption of WWP2 interactions with inhibitory Smad7 can stabilise Smad7 protein levels and prevent TGFß-induced EMT. Collectively, our data suggest that WWP2-N can stimulate WWP2-FL leading to increased activity against unstimulated Smad2 and Smad3, and that Smad7 is a preferred substrate for WWP2-FL and WWP2-C following prolonged TGFß stimulation. Significantly, this is the first report of an interdependent biological role for distinct HECT E3 ubiquitin ligase isoforms, and highlights an entirely novel regulatory paradigm that selectively limits the level of inhibitory and activating Smads