7,198 research outputs found
Tunneling magnetoresistance in diluted magnetic semiconductor tunnel junctions
Using the spin-polarized tunneling model and taking into account the basic
physics of ferromagnetic semiconductors, we study the temperature dependence of
the tunneling magnetoresistance (TMR) in the diluted magnetic semiconductor
(DMS) trilayer heterostructure system (Ga,Mn)As/AlAs/(Ga,Mn)As. The
experimentally observed TMR ratio is in reasonable agreement with our result
based on the typical material parameters. It is also shown that the TMR ratio
has a strong dependence on both the itinerant-carrier density and the magnetic
ion density in the DMS electrodes. This can provide a potential way to achieve
larger TMR ratio by optimally adjusting the material parameters.Comment: 5 pages (RevTex), 3 figures (eps), submitted to PR
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Comment on "A pilot-scale field study: in situ treatment of PCB-impacted sediments with bioamended activated carbon"
The intensified constructed wetlands are promising for treatment of ammonia stripped effluent: nitrogen transformations and removal pathways
This study investigated the treatment performance and nitrogen removal mechanism of highly alkaline ammonia-stripped digestate effluent in horizontal subsurface flow constructed wetlands (CWs). A promising nitrogen removal performance (up to 91%) was observed in CWs coupled with intensified configurations, i.e., aeration and effluent recirculation. The results clearly supported that the higher aeration ratio and presence of effluent recirculation are important to improve the alkalinity and pollutant removal in CWs. The influent pH (>10) was significantly decreased to 8.2ā8.8 under the volumetric hydraulic loading rates of 0.105 and 0.21 d-1 in the CWs. Simultaneously, up to 91% of NH4+-N removal was achieved under the operation of a higher aeration ratio and effluent recirculation. Biological nitrogen transformations accounted for 94% of the consumption of alkalinity in the CWs. The significant enrichment of Ī“15N-NH4+ in the effluent (47ā58ā°) strongly supports the occurrence of microbial transformations for NH4+-N removal. However, relatively lower enrichment factors of Ī“15N-NH4+ (ā1.8 ā° ā ā11.6ā°) compared to the values reported in previous studies reflected the inhibition effect of the high pH alkaline environment on nitrifiers in these CWs
PMS64 Persistence Rate With Subcutaneous Biologic Therapies in Patients With Rheumatoid Arthritis (Ra)
Software fault-tolerance by design diversity DEDIX: A tool for experiments
The use of multiple versions of a computer program, independently designed from a common specification, to reduce the effects of an error is discussed. If these versions are designed by independent programming teams, it is expected that a fault in one version will not have the same behavior as any fault in the other versions. Since the errors in the output of the versions are different and uncorrelated, it is possible to run the versions concurrently, cross-check their results at prespecified points, and mask errors. A DEsign DIversity eXperiments (DEDIX) testbed was implemented to study the influence of common mode errors which can result in a failure of the entire system. The layered design of DEDIX and its decision algorithm are described
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Optimisation of bioscrubber systems to simultaneously remove methane and purify wastewater from intensive pig farms
The use of bioscrubber is attracting increasing attention for exhaust gas treatment in intensive pig farming. However, the challenge is to improve the methane (CH4) removal efficiency as well as the possibility of pig house wastewater treatment. Three laboratory-scale bioscrubbers, each equipped with different recirculation water types, livestock wastewater (10-times-diluted pig house wastewater supernatant), a methanotroph growth medium (10-times-diluted), and tap water, were established to evaluate the performance of CH4 removal and wastewater treatment. The results showed that enhanced CH4 removal efficiency (25%) can be rapidly achieved with improved methanotrophic activity due to extra nutrient support from the wastewater. The majority of the CH4 was removed in the middle to end part of the bioscrubbers, which indicated that CH4 removal could be potentially optimised by extending the length of the reactor. Moreover, 52ā86% of the ammonium (NH4+-N), total organic carbon (TOC), and phosphate (PO43ā-P) removal were simultaneously achieved with CH4 removal in the present study. Based on these results, this study introduces a low-cost and simple-to-operate method to improve CH4 removal and simultaneously treat pig farm wastewater in bioscrubbers
Comment: Closing phosphorus cycle from natural waters: re-capturing phosphorus through an integrated water-energy-food strategy
Geometric analysis and formability of the cubic A2BX6 vacancy ordered double perovskite structure
A geometric analysis of the cubic A2BX6 structure commonly formed by metal halides is presented. Using the āhard-sphereā approximation, where the ions are represented by spheres of a fixed radius, we derive four limiting models that each constrain the distances between constituent ions in different ways. We compare the lattice parameters predicted by these four models with experimental data from the Inorganic Crystal Structure Database (ICSD). For the fluorides, the maintenance of the AX bond length at the sum of the A and X radii gives the best approximation of the lattice parameter, leading to structures with widely separated BX6 octahedra. For the heavier halides, a balance between forming an A-site cavity of the correct size and maintaining suitable anionāanion distances determines the lattice parameter. It is found that in many A2BX6 compounds of heavier halides, the neighboring octahedra show very significant anionāanion overlap. We use these models to predict a compound with A-site rattling and use density functional theory (DFT) to confirm this prediction. Finally, we use the geometric models to derive formability criteria for vacancy-ordered double perovskites
Volatility spillovers and carbon price in the Nordic wholesale electricity markets
This is the final version. Available from Elsevier via the DOI in this record.āÆData availability:
Datasets related to this electricity intraday prices can be found at
Nord Pool Elspot (Day-ahead markets) and Elbas (Intraday markets),
https://www.nordpoolgroup.
com/services/power-market-data-services/. This research dataset obtained from Nord Pool is confidential and cannot be redistributed or
posted on a website. Access requests to Nord Pool data portal shall be
made to Nord Pool. Datasets related to energy market prices and carbon
market prices can be found at Thomson Reuters Eikon, and Bloomberg
and are available upon reasonable request with the corresponding
author.This paper investigates price volatility and spillovers in the Nordic electricity wholesale markets. We use the
Time-Varying Parameter Vector Autoregressive (TVP-VAR), Rolling Window-based VAR (RW-VAR), and high
dimensional VAR with common factors (VAR-CF) methods and analyze the integration dynamics among these
markets and impact of carbon prices on volatility spillovers. We use 107,352 hourly price data from January
2010 to March 2022. The novelty of this research is four-fold. First, we adopt a connectedness approach to
explore volatility interactions among the four Nordic markets, contributing to the scarce literature on volatility in
this market. Second, we segment the Norwegian market into southern and northern regions, revealing differences
in volatility spillover patterns. Third, we investigate the effect of carbon prices on volatility spillovers and market
dynamics. Last, we show significant contribution of covariances to interdependence among markets. We find
significant connectedness between the Nordic markets, with an average Total Connectedness Index of between
50% (with a system of variance) and 90% (with a system of both variance and covariance). Sweden is the sole net
volatility spillover transmitter, while Denmark experiences the largest shocks from the system. We further find
that carbon prices exert a 5% significant impact on the volatility spillover index.Copenhagen School of Energy Infrastructure (CSEI
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