7,257 research outputs found
Generalized Ohm\u27s Law In A 3-D Reconnection Experiment
We report the measurement of non-ideal terms of the generalized Ohm\u27s law at a reconnection site of a weakly collisional laboratory magnetohydrodynamic plasma. Results show that the Hall term dominates the measured terms; resistive and electron inertia terms are small. We suggest that electron pressure (not measured) supports the observed quasistatic reconnection rate, and that anomalous resistivity, while not ruled out, is not required to account for the results
Three-Dimensional Structure Of Magnetic Reconnection In A Laboratory Plasma
The local three-dimensional structure of magnetic reconnection has been measured for the first time in a magnetohydrodynamic (MHD) laboratory plasma at the Swarthmore Spheromak Experiment. An array of 600 magnetic probes which resolve ion inertial length and MHD time scale dynamics on a single shot basis measured the magnetic structure of partial spheromak merging events. Counter-helicity spheromaks merge rapidly, and reconnection activity clearly self-generates a local component of B which breaks the standard 2D symmetry at the ion inertial scale. Consistent with prior results, no reconnection is observed for co-helicity merging
Experimental Observation Of Energetic Ions Accelerated By Three-Dimensional Magnetic Reconnection In A Laboratory Plasma
Magnetic reconnection is widely believed responsible for heating the solar corona as well as for generating X-rays and energetic particles in solar flares. On astrophysical scales, reconnection in the intergalactic plasma is a prime candidate for a local source (Mpc) of cosmic rays exceeding the Greisen-Zatsepin-Kuzmin cutoff (∼10(19) eV). In a laboratory astrophysics experiment, we have made the first observation of particles accelerated by magnetic reconnection events to energies significantly above both the thermal and the characteristic magnetohydrodynamic energies. These particles are correlated temporally and spatially with the formation of three-dimensional magnetic structures in the reconnection region
Challenges and solutions for Latin named entity recognition
Although spanning thousands of years and genres as diverse as liturgy, historiography, lyric and other forms of prose and poetry, the body of Latin texts is still relatively sparse compared to English. Data sparsity in Latin presents a number of challenges for traditional Named Entity
Recognition techniques. Solving such challenges and enabling reliable Named Entity Recognition in Latin texts can facilitate many down-stream applications, from machine translation to digital historiography, enabling Classicists, historians, and archaeologists for instance, to track
the relationships of historical persons, places, and groups on a large scale. This paper presents the first annotated corpus for evaluating Named Entity Recognition in Latin, as well as a fully supervised model that achieves over 90% F-score on a held-out test set, significantly outperforming a competitive baseline. We also present a novel active learning strategy that predicts how many and which sentences need to be annotated for named entities in order to attain a specified degree
of accuracy when recognizing named entities automatically in a given text. This maximizes the productivity of annotators while simultaneously controlling quality
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Spectrophotometric analysis of ternary uranyl systems to replace tri-N-butyl phosphate (TBP) in used fuel reprocessing
In this report, the interaction of monoamide/diamide and monoamide/diglycolamide mixtures with UO2+2 are investigated in pH = 1 methanolic nitric acid media. These monoamides include N,N-dimethylacetamide (DMAA), N,N-diethylacetamide (DEAA), N,N-dibutylacetamide (DBAA) and N,N-dibutylbutanamide (DBBA). N,N,N′N′-tetraethylmalonamide (TEMA) and N,N,N′,N′-tetraethyldiglycolamide (TEDGA), which were chosen as model diamides and diglycolamides, respectively. Complex stability constants for each ligand were modelled using the Stability Quotients Using Absorbance Data program using UV–visible data. Complex stoichiometry of ligand mixtures was determined using Job plots and UV–Vis spectrometry. Monoamides were confirmed to produce only disolvate complexes with UO2+2 in solution. The log10(K) values for monoamides were found to be independent of amine-side chain length, but were slightly dependent on the carbonyl-side chain length. TEDGA was found to produce multiple uranyl complexes in solution. Job plot data indicated that the uranyl cation strongly prefers to bond either only with the monoamide or diamide in ternary monoamide–diamide–UO2 systems. Monoamide–diglycolamide–UO2 systems were more complicated, with Job plot data indicating the potential for multiple ternary species being present is dependent on the monoamide structure
Synthesis and characterization of biodegradable lignin nanoparticles with tunable surface properties
Lignin nanoparticles can serve as biodegradable carriers of biocidal actives with minimal environmental footprint. Here we describe the colloidal synthesis and interfacial design of nanoparticles with tunable surface properties using two different lignin precursors, Kraft (Indulin AT) lignin and Organosolv (high-purity lignin). The green synthesis process is based on flash precipitation of dissolved lignin polymer, which enabled the formation of nanoparticles in the size range of 45–250 nm. The size evolution of the two types of lignin particles is fitted on the basis of modified diffusive growth kinetics and mass balance dependencies. The surface properties of the nanoparticles are fine-tuned by coating them with a cationic polyelectrolyte, poly(diallyldimethylammonium chloride). We analyze how the colloidal stability and dispersion properties of these two types of nanoparticles vary as a function of pH and salinities. The data show that the properties of the nanoparticles are governed by the type of lignin used and the presence of polyelectrolyte surface coating. The coating allows the control of the nanoparticles’ surface charge and the extension of their stability into strongly basic regimes, facilitating their potential application at extreme pH conditions
Prehabilitation Influences Exercise-Related Psychological Constructs Such as Self-Efficacy and Outcome Expectations to Exercise
Brown, K, Loprinzi, PD, Brosky, JA, and Topp, R. Prehabilitation influences exercise-related psychological constructs such as self-efficacy and outcome expectations to exercise. J Strength Cond Res 28(1): 201–209, 2014—Osteoarthritis (OA) is a clinical condition affecting more than 27 million Americans. There is no known cure for OA other than replacing the diseased joint with a joint prosthesis, a process called total knee arthroplasty (TKA). The TKA projections for the year 2016 are 1,046,000, and this number is predicted to increase by 600% to more than 3.4 million cases by 2030. The purpose of this study was to determine whether knee OA patients who engage in guided exercise (prehabilitation) before their TKA report higher levels of self-efficacy to exercise (SEE) and higher outcome expectations for exercise (OEE) than those who do not. Thirty-one participants were randomized into 2 groups (16 in prehabilitation group [PRE] and 15 in control group [CON]), all participants completed the protocol (22 women and 9 men). The PRE group participated in an exercise intervention (prehabilitation) 3 times per week for 8 weeks before TKA. One-way repeated measures analysis of variance was used to investigate the effects of group (PRE vs. CON), time (baseline T1, T2, T3, and T4), and the interaction of group and time on the dependent variables of SEE and OEE. This analysis indicated that SEE did not change over time (p = 0.62) or between the groups (p = 0.86). The analysis of the OEE indicated a significant time effect (p = 0.008). Post hoc analysis indicated that the CON group significantly declined between T2 and T4. The PRE group did not significantly change their OEE over the 4 data collection points of the study
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