Objective image quality assessment (IQA) plays an important role in the development of multimedia applications. Prediction of IQA metric should be consistent with human perception. The release of the ...newest IQA database (TID2013) challenges most of the widely used quality metrics (e.g., peak-to-noise-ratio and structure similarity index). We propose a new methodology to build the metric model using a regression approach. The new IQA score is set to be the nonlinear combination of features extracted from several difference of Gaussian (DOG) frequency bands, which mimics the human visual system (HVS). Experimental results show that the random forest regression model trained by the proposed DOG feature is highly correspondent to the HVS and is also robust when tested by available databases.
A new metal‐free radical 5‐exo‐dig cyclization of phenol‐linked 1,6‐enynes with O2, 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO), and tBuONO is described. With this general method, carbonylated ...benzofurans can be accessed through incorporation of two oxygen atoms into the product from O2 and TEMPO through dioxygen activation and oxidative cleavage of the NO bond, respectively.
Benzofurans are obtained by the tBuONO‐initiated radical 5‐exo‐dig cyclization of enynes under mild and metal‐free conditions. The two oxygen atoms that constitute the newly formed carbonyl groups of the benzofuran system originate from O2 and 2,2,6,6‐tetramethyl‐1‐piperidinyloxy (TEMPO), respectively.
Ammonia removal and recovery from wastewater have been a critical issue worldwide and a key to achieve a sustainable nitrogen cycle and circular economy. Conventional ammonia removal via air ...stripping needs pH adjustment pretreatment with chemical additives while electrokinetic technologies can provide electrochemically in-situ pH control without chemicals needed. The integration of electrokinetic and air stripping technologies is a potential process for the simultaneous removal/recovery of ammonia/ammonium from wastewater. This study consolidates research findings of the separate research domains of electrokinetic and air stripping technologies and aims to identify an integrated process for the simultaneous nitrogen removal/recovery from waste streams. Process integration involves research on improved ammonia removal efficiencies and liquid side mass transfer performances using innovative air stripping system designs and gas-liquid contactors, e.g., rotating packed beds and membrane contactors, compared with the conventional stripping tower process. Findings in the applications and performances of electrokinetic separation processes, including electrodialysis, electrodeionization, capacitive deionization, electrochemical cell, and bio-electrochemical systems, on the removal/recovery of ammonia/ammonium, are a crucial link to integration as well. Energy consumptions between 5–20.4 kWh/kg–NH4-N with a removal ratio of around 90% for electrokinetic processes are currently achievable, and some groups can be implemented on the biodegradable organic substrates from urine. Innovative hybrid technologies of ammonia nitrogen removal/recovery with energy production and co-product valorization that reduce the overall cost and energy consumption via integrated processes optimization, and discussions on the environmental impact assessment (via life cycle assessment) and economic benefit analysis (via techno-economic analysis) of ammonia recovery practices on waste streams are investigated.
•Advanced NH3 stripping processes enhance the gas-liquid mass transfer rate.•Energy-efficient electrokinetic processes facilitate NH4+/NH3 recovery.•Novel hybrid technology for NH4+/NH3 recovery and energy production was discussed.•Establishes a sustainable nitrogen cycle to promote environmental and economic benefits.
Sub‐freezing temperature presents a significant challenge to the survival of current Li‐ion batteries (LIBs) as it leads to low capacity retention and poor cell rechargeability. The electrolyte in ...commercial LIBs relies too heavily on ethylene carbonate (EC) to produce a stable solid electrolyte interphase (SEI) on graphite (Gr) anodes, but its high melting point (36.4 °C) severely restricts ion transport below 0 °C, causing energy loss and Li plating. Here, a class of EC‐free electrolytes that exhibits remarkable low‐temperature performance without compromising cell lifespan is reported. It is found that at sub‐zero temperatures, EC forms highly resistive SEI that seriously impedes electrode kinetics, whereas EC‐free electrolytes create a highly stable, low‐impedance SEI through anion decomposition, which boosts capacity retention and eliminates Li plating during charging. Pouch‐type LiCoO2 (LCO)|Gr cells with EC‐free electrolytes sustain 900 cycles at 25 °C with 1 C charge/discharge, and LiNi0.85Co0.10Al0.05O2 (NCA)|Gr cells last 300 cycles at −15 °C with 0.3 C charge, both among the best‐performing in the literature under comparable conditions. Even at −50 °C, the NCA|Gr cell with EC‐free electrolytes still delivers 76% of its room‐temperature capacity, outperforming EC‐based electrolytes.
A new class of ethylene carbonate (EC)‐free electrolytes, based on methyl acetate and fluorinated ethers, is proposed for Li‐ion batteries operating at sub‐freezing temperatures. The EC‐free electrolyte demonstrates all‐round performance advantages over the traditional EC‐based electrolyte and presents a viable solution to improve the capacity retention and rechargeability of metal‐ion batteries in cold climates.
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•Dynamic recrystallization grains nucleated at 4-, 3- and 2-grain junctions in turn.•Two proposed recrystallization nucleation mechanisms operate well at grain junctions.•The ...nucleation priority of one grain junction can be predicted by Taylor factors.
Despite the important role of grain junctions to the dynamic recrystallization (DRX) of nickel-based superalloys, the nucleation mechanisms operating there and the influence factors besides deformation condition on nucleation priority are still unclear. The microstructure evolution considering grain junction effects has not been explored in depth yet. In this paper, DRX nucleation at the 2-, 3- and 4-grain junctions of a nickel-based superalloy was investigated. A proposed passive grain boundary bulging (PGBB) mechanism operated well at 2-grain junctions, and accounted for the continuity of necklace structure during the early stage of hot deformation. For the 3-grain junctions, a two-step strain-induced bulging of grain boundary fragments, which closely adjoined the junctions, was found to dominate the DRX nucleation. In addition, an increasing nucleation priority from 2-, 3- to 4-grain junctions was confirmed by the established thermodynamic model, while the nucleation priority differences of the same kind grain junctions were quantitatively analyzed by using the Taylor factors of their component grains. Finally, the DRX microstructure evolution of a 4-grain stacking unit during hot deformation was described. The understanding of DRX associated with 2-, 3- to 4-grain junctions made it more effective to tailor the microstructure of nickel-based superalloy forgings.
The pathogenesis of mucoinfective lung disease in cystic fibrosis (CF) patients likely involves poor mucus clearance. A recent model of mucus clearance predicts that mucus flow depends on the ...relative mucin concentration of the mucus layer compared with that of the periciliary layer; however, mucin concentrations have been difficult to measure in CF secretions. Here, we have shown that the concentration of mucin in CF sputum is low when measured by immunologically based techniques, and mass spectrometric analyses of CF mucins revealed mucin cleavage at antibody recognition sites. Using physical size exclusion chromatography/differential refractometry (SEC/dRI) techniques, we determined that mucin concentrations in CF secretions were higher than those in normal secretions. Measurements of partial osmotic pressures revealed that the partial osmotic pressure of CF sputum and the retained mucus in excised CF lungs were substantially greater than the partial osmotic pressure of normal secretions. Our data reveal that mucin concentration cannot be accurately measured immunologically in proteolytically active CF secretions; mucins are hyperconcentrated in CF secretions; and CF secretion osmotic pressures predict mucus layer-dependent osmotic compression of the periciliary liquid layer in CF lungs. Consequently, mucin hypersecretion likely produces mucus stasis, which contributes to key infectious and inflammatory components of CF lung disease.
New sequencing technologies promise a new era in the use of DNA sequence. However, some of these technologies produce very short reads, typically of a few tens of base pairs, and to use these reads ...effectively requires new algorithms and software. In particular, there is a major issue in efficiently aligning short reads to a reference genome and handling ambiguity or lack of accuracy in this alignment. Here we introduce the concept of mapping quality, a measure of the confidence that a read actually comes from the position it is aligned to by the mapping algorithm. We describe the software MAQ that can build assemblies by mapping shotgun short reads to a reference genome, using quality scores to derive genotype calls of the consensus sequence of a diploid genome, e.g., from a human sample. MAQ makes full use of mate-pair information and estimates the error probability of each read alignment. Error probabilities are also derived for the final genotype calls, using a Bayesian statistical model that incorporates the mapping qualities, error probabilities from the raw sequence quality scores, sampling of the two haplotypes, and an empirical model for correlated errors at a site. Both read mapping and genotype calling are evaluated on simulated data and real data. MAQ is accurate, efficient, versatile, and user-friendly. It is freely available at http://maq.sourceforge.net.
Spectral unmixing is an important technique in hyperspectral image applications. Recently, sparse regression has been widely used in hyperspectral unmixing, but its performance is limited by the high ...mutual coherence of spectral libraries. To address this issue, a new sparse unmixing algorithm, called double reweighted sparse unmixing and total variation (TV), is proposed in this letter. Specifically, the proposed algorithm enhances the sparsity of fractional abundances in both spectral and spatial domains through the use of double weights, where one is used to enhance the sparsity of endmembers in spectral library, and the other is introduced to improve the sparsity of fractional abundances. Moreover, a TV-based regularization is further adopted to explore the spatial-contextual information. As such, the simultaneous utilization of both double reweighted l 1 minimization and TV regularizer can significantly improve the sparse unmixing performance. Experimental results on both synthetic and real hyperspectral data sets demonstrate the effectiveness of the proposed algorithm both visually and quantitatively.
Microplastics, as emerging contaminants in the global environment, have become a cause for concern for both academics and the public. The present understanding of microplastic pollution is primarily ...focused on marine environments, and less attention has been given to freshwater environments, in particular, to urban rivers. In this study, microplastics were sampled from surface water and sediments in 14 sites located in the lower course of the Pearl River. These sampling sites are located along Guangzhou of South China, with built-up areas being the dominant land use. The abundances of microplastics in surface water and sediments ranged from 379 to 7924 items·m−3 and 80 to 9597 items·kg−1, respectively. Polyethylene and polypropylene were the common types of microplastics, together accounting for 64.3% and 73.8% of surface water and sediment samples, respectively. Fibers were the dominant microplastic shapes in both water and sediment samples. The abundances of microplastics varied in surface water and sediments with each site, which might be affected by multiple factors. Our results indicated that wastewater treatment plants (WWTP) could reduce microplastics from municipal sewage which was finally discharged into the Pearl River along Guangzhou.
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•Microplastics in the Pearl River along Guangzhou were investigated for the first time.•Fibers were detected in both surface water and sediment samples.•PE and PP were the dominant polymer types in surface water and sediments.•WWTP in Guangzhou could reduce microplastic pollution in the municipal sewage.
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