Investigation on the interactions among lignocellulosic constituents and minerals of biomass and their influences on co-firing

The influences of biomass constituents, such as lignocellulosic components and minerals, on the combustion of coal/biomass blends are of significant importance in co-firing due to its potential impacts on ignition, flame stability and burnout. In this research, combustion characteristics of pure lignocellulosic elements, Rosewood, Mengxi coal and their blends were studied in detail. The effect of minerals in Rosewood on combustion of biomass/Mengxi coal blends was investigated which revealed reductions in the ignition (≤20 °C), peak (≤12 °C)and burnout temperatures (≤6 °C). The results also demonstrate the existence of interactions between lignocellulosic constituents in the model biomass, which is dominated by the interactions of cellulose-derived products with xylan and lignin respectively which led to ∼8% reduction in char oxidation temperature. The minerals in biomass showed different impacts at different stages of the combustion process, such as inhibition effect during the devolatilization stage, and promotive synergy (mainly due to calcium)on ignition and char oxidation. © 2019 Elsevier Lt

Production of H2-rich syngas from lignocellulosic biomass using microwave-assisted pyrolysis coupled with activated carbon enabled reforming

This study focuses on the use of a microwave reactor that combines biomass pyrolysis, at mild temperature, with catalytic reforming of the pyrolytic gas, using activated carbon, for generating hydrogen-rich synthesis gas. The traditional pyrolysis of biomass coupled with the reforming of its pyrolytic yields were also conducted using an electrically heated reactor. The bio-oil attained from conventional pyrolysis was higher in comparison to the yield from microwave pyrolysis. The reforming of the pyrolytic gas fraction led to reductions in bio-oil yield to <3.0 wt%, with a simultaneous increase in gaseous yields. An increase in the syngas and H2 selectivity was discovered with the reforming process such that the use of microwave pyrolysis with activated carbon reforming produced 85 vol% synthesis gas fraction containing 55 vol% H2 in comparison to the 74 vol% syngas fraction with 30 vol% H2 obtained without the reforming. Cracking reactions were improved with microwave heating, while deoxidation and dehydrogenation reactions were enhanced by activated carbon, which creates a reduction environment. Consequently, these reactions generated H2-rich syngas formation. The approach implemented in this study revealed higher H2, syngas yield and that the overall LHV of products has huge potential in the transformation of biomass into high-value synthesis gas

A critical review of methods for analyzing freshwater eutrophication

Water eutrophication is a global environmental problem that poses serious threats to aquatic ecosystems and human health. The evaluation of eutrophication provides a theoretical basis and technical guidance for the management and rehabilitation of water ecosystems. In the last four decades, dozens of evaluation methods have been applied to freshwater eutrophication, but there is a clear need to optimize and standardize the most suitable methods. We have addressed this gap by presenting a systematic review of methodologies. Due to the diversity and complexity of water bodies, no single evaluation method was identified that would adequately represent eutrophication under all scenarios. We demonstrate that lakes can best be assessed using the trophic level index (TLI) method, reservoirs and wetlands the trophic state index (TSI) and fuzzy comprehensive evaluation (FCE) method, respectively, and rivers the FCE method or back propagation (BP) neural network methods. More recently applied methodologies including spectral imaging and 3-D mapping of water quality using underwater gliders allow greater resolution and can be effective in managing waterbodies to avoid future eutrophication. The aim of this review is to guide future studies on the most appropriate methods available for assessing and reporting water eutrophication

One for Multiple: Physics-informed Synthetic Data Boosts Generalizable Deep Learning for Fast MRI Reconstruction

Magnetic resonance imaging (MRI) is a principal radiological modality that provides radiation-free, abundant, and diverse information about the whole human body for medical diagnosis, but suffers from prolonged scan time. The scan time can be significantly reduced through k-space undersampling but the introduced artifacts need to be removed in image reconstruction. Although deep learning (DL) has emerged as a powerful tool for image reconstruction in fast MRI, its potential in multiple imaging scenarios remains largely untapped. This is because not only collecting large-scale and diverse realistic training data is generally costly and privacy-restricted, but also existing DL methods are hard to handle the practically inevitable mismatch between training and target data. Here, we present a Physics-Informed Synthetic data learning framework for Fast MRI, called PISF, which is the first to enable generalizable DL for multi-scenario MRI reconstruction using solely one trained model. For a 2D image, the reconstruction is separated into many 1D basic problems and starts with the 1D data synthesis, to facilitate generalization. We demonstrate that training DL models on synthetic data, integrated with enhanced learning techniques, can achieve comparable or even better in vivo MRI reconstruction compared to models trained on a matched realistic dataset, reducing the demand for real-world MRI data by up to 96%. Moreover, our PISF shows impressive generalizability in multi-vendor multi-center imaging. Its excellent adaptability to patients has been verified through 10 experienced doctors' evaluations. PISF provides a feasible and cost-effective way to markedly boost the widespread usage of DL in various fast MRI applications, while freeing from the intractable ethical and practical considerations of in vivo human data acquisitions.Comment: 22 pages, 9 figures, 1 tabl

Direct observation of spin polarization in epitaxial Fe3O4(001)/MgO thin films grown by magnetron sputtering

We obtained epitaxial single-crystal Fe3O4(001)/MgO(001) thin films by magnetron sputtering. The high quality of the grown Fe3O4 films was confirmed by reflection high-energy electron diffraction and x-ray photoelectron spectroscopy. Atomic magnetic properties of Fe3O4(001)/MgO(001) were investigated using vibrating sample magnetometry and x-ray magnetic circular dichroism. The values of saturation magnetization and magnetic moment are 407 ± 5 emu/cm3 (3.26 ± 0.04 μ B / (f. u.)) and 3.31 ± 0.15 μ B / (f. u.), respectively, in the Fe3O4 film as thin as 5 nm, which are close to the bulk values. The spin polarization was directly measured using spin-resolved photoemission spectroscopy. The measured spin polarization has a maximum value of -42% ± 3%, which is comparable to the theoretical value for the (2 × 2)R45° reconstructed Fe3O4(001) surface. Furthermore, the film thickness-dependent measurements indicate that the anti-phase boundaries significantly decrease the spin polarization rather than the lattice mismatch. Our results demonstrate that epitaxial Fe3O4(001)/MgO thin films grown by magnetron sputtering have desired magnetic properties, facilitating the potential application of Fe3O4-based spintronic devices

Study on Electronic Energy Meter Failure Power Calculation Based on Metering Automation Systems

Whether the energy metering device is accurate or not is related to the economic interests of both the division and sale of electric power, but in reality, energy metering device failure is inevitable. When a failure occurs, it must be certain of the correct way to calculate the accrued power. Classic methods of electricity are estimated by returning and adding “correction coefficient”, but the fault characteristics of electronic table differs from previous induction meter. Electrical parameters and the cumulative power is erratic, leading to “correction coefficient method” failure. This paper describes a means of electrical parameter automation metering systems continuously recorded using the thought of “integration”, the correction coefficient to compensate for the lack of power to solve real projections fault electronic energy meter problem

A reconfigurable rectifier-based power improving method of free-standing two-coil magnetic field energy harvesters over a wide load range

Free-standing magnetic field energy harvesters (FSMFEHs) have promising potential in charging sensors used in electrical power grids. The output power of the FSMFEH is highly dependent on the load resistance. However, the load resistance of the sensors varies over a wide range during the operation process. Therefore, a crucial challenge for an FSMFEH system is to maintain high output power over a wide load range. In this letter, an innovative reconfigurable rectifier-based FSMFEH system with two coils connected in parallel is proposed. First, a new structure of two identical coils in parallel is proposed in magnetic energy harvesting applications. Then, a reconfigurable rectifier with two operation modes is developed to incorporate the new coil structure. By switching between the full-bridge mode and the half-bridge mode according to the actual load demand, the proposed FSMFEH can maintain high output power over a wide load range. In addition, the mode transition can be easily achieved by shorting one of the diodes, leading to a simple and low-loss control. The effectiveness of the proposed FSMFEH system is verified based on a laboratory prototype. It is provided that the experimental result is consistent with the theoretical analysis. The output power can be maintained above 8.19 mW within the 50-150

Detachable Soft Actuators with Tunable Stiffness Based on Wire Jamming

The integration of variable stiffness materials and structures into soft robots is a popular trend, allowing soft robots to switch between soft and rigid states in different situations. This concept combines the advantages of rigid mechanisms and soft robots, resulting in not only excellent flexibility but also tunable stiffness for high load capacity and fast and precise operation. Here, a stiffness-tunable soft actuator based on wire/fiber jamming structure is proposed, where the fiber-reinforced soft actuator is responsible for the bending motion, and the jamming structure acts as a stiffness-tunable layer controlled by vacuum pressure. The primary design objective of this study is to fabricate a jamming structure with wide-range stiffness, universal adaptability and high dexterity. Thus, the behaviors of wire/fiber jamming structures with different layouts, materials and wire arrangements are analyzed, and a theoretical model is developed to predict the effect of geometric parameters. Experimental characterizations show that the stiffness can be significantly enhanced in the bending direction, while the stiffness is smaller in the torsion direction. Additionally, by integrating Velcro strips into the design, a quick and detachable scheme for the stiffness-tunable soft actuator is achieved. Application examples exhibit high load capacity and good shape adaptability

Synthesis of Ag-La0.8Sr0.2MnO3 (LSM-Ag) Composite Powder and Its Application in Magnesium Air Battery

La0.8Sr0.2MnO3 (LSM) catalyst is prepared via a sol-gel method and modified via a typical silver mirror reaction. Silver ammonia solution is reduced in a polyvinylpyrrolidone (PVP)-containing solution to obtain silver nanoparticles and sodium dodecyl sulfate (SDS) is added as a surfactant. The microstructure and morphology of the LSM-Ag composite powder are characterized. According to the results, the Ag particles precipitate on the LSM surface in elemental form and the grain size is about one hundred nanometers. The analysis of electrocatalytic performance of LSM-Ag cathodes with different amounts of silver loading reveals that the number of electrons transferred during the oxygen reduction reaction (ORR) of the cathode with an Ag content of 14% by weight reached 3.9, which is very close to that of commercial Pt/C catalysts. Similarly, the maximum power density of the air battery made of LSM-14%Ag is 73 mW/cm2, which exceeds that of 63 mW/cm2, found for the LSM battery. Finally, increasing the amount of silver loading allows one to improve the electrochemical performance of LSM catalysts. The best effect is achieved when the Ag loading exceeds 14%