687 research outputs found
Development, implementation, and validation of a generic nutrient recovery model (NRM) library
The reported research developed a generic nutrient recovery model (NRM) library based on detailed chemical solution speciation and reaction kinetics, with focus on fertilizer quality and quantity as model outputs. Dynamic physicochemical three-phase process models for precipitation/crystallization, stripping and acidic air scrubbing as key unit processes were developed. In addition, a compatible biological-physicochemical anaerobic digester model was built. The latter includes sulfurgenesis, biological N/P/K/S release/uptake, interactions with organics, among other relevant processes, such as precipitation, ion pairing and liquid-gas transfer. Using a systematic database reduction procedure, a 3- to 5-fold improvement of model simulation speeds was obtained as compared to using full standard thermodynamic databases. Missing components and reactions in existing standard databases were discovered. Hence, a generic nutrient recovery database was created for future applications. The models were verified and validated against a range of experimental results. Their functionality in terms of increased process understanding and optimization was demonstrated
Motor imagery alone drives corticospinal excitability during concurrent action observation and motor imagery
We studied the motor simulation processes involved in concurrent action observation and motor imagery (AO+MI) using motor evoked potentials induced by transcranial magnetic stimulation. During congruent AO+MI, participants were shown videos of a modelâs hand performing rhythmical finger movements, and they imagined moving the same finger of their own hand in synchrony with the observed finger. During incongruent AO+MI, the imagery task involved a different finger from the observed one. As expected, congruent AO+MI yielded robust facilitatory effects, relative to baseline, only in the effector involved in the task. Incongruent AO+MI produced equally pronounced effects in the effector that was engaged in MI, whilst no corticospinal facilitation was found for the effector corresponding to the observed action. We further replicated that engaging in pure AO without MI does not produce reliable effects. These results do not support the proposal that observed and imagined action are both simulated at the level of the primary motor cortex. Rather, motor imagery alone can sufficiently explain the observed effects in both AO+MI conditions. This bears clear implications for the application of AO+MI procedures in sport and neurorehabilitation
Presence and mobility of arsenic in estuarine wetland soils of the Scheldt estuary (Belgium)
We aimed to assess the presence and availability of arsenic (As) in intertidal marshes of the Scheldt estuary. Arsenic content was determined in soils sampled at 4 sampling depths in 11 marshes, together with other physicochemical characteristics. Subsequently, a greenhouse experiment was set up in which pore water arsenic (As) concentrations were measured 4 times in a 298-day period in 4 marsh soils at different sampling depths (10, 30, 60 and 90 cm) upon adjusting the water table level to 0, 40 and 80 cm below the surface of these soils. The As content in the soil varied significantly with sampling depth and location. Clay and organic matter seem to promote As accumulation in the upper soil layer (0â20 cm below the surface), whereas sulfide precipitation plays a significant role at higher sampling depths (20â 100 cm below the surface). The As concentrations in the pore water of the greenhouse experiment often significantly exceeded the Flemish soil sanitation thresholds for groundwater. There were indications that As release is not only affected by the reductive dissolution of Fe/Mn oxides, but also by e.g. a direct reduction of As(V) to As(III). Below the water table, sulfide precipitation seems to lower As mobility when reducing conditions have been sufficiently established. Above the water table, sulfates and bicarbonates induce As release from the solid soil phase to the pore water
Development of a BelRAI screening instrument for correctional facilities preparatory phase for testing
Commissioned by the Belgian federal government, a BelRAI screening tool for the detention context was developed. The aim of this screening instrument is to collect all information necessary for care providers inside prison to decide whether a penitentiary care trajectory is needed
Observing binary inspiral in gravitational radiation: One interferometer
We investigate the sensitivity of individual LIGO/VIRGO-like interferometers
and the precision with which they can determine the characteristics of an
inspiralling binary system. Since the two interferometers of the LIGO detector
share nearly the same orientation, their joint sensitivity is similar to that
of a single, more sensitive interferometer. We express our results for a single
interferometer of both initial and advanced LIGO design, and also for the LIGO
detector in the limit that its two interferometers share exactly the same
orientation. We approximate the evolution of a binary system as driven
exclusively by leading order quadrupole gravitational radiation. To assess the
sensitivity, we calculate the rate at which sources are expected to be
observed, the range to which they are observable, and the precision with which
characteristic quantities describing the observed binary system can be
determined. Assuming a conservative rate density for coalescing neutron star
binary systems we expect that the advanced LIGO detector will observe
approximately 69~yr with an amplitude SNR greater than 8. Of these,
approximately 7~yr will be from binaries at distances greater than
950~Mpc. We explore the sensitivity of these results to a tunable parameter in
the interferometer design (the recycling frequency). The optimum choice of the
parameter is dependent on the goal of the observations, e.g., maximizing the
rate of detections or maximizing the precision of measurement. We determine the
optimum parameter values for these two cases.Comment: 40 pages (plus 7 figures), LaTeX/REVTEX3.0, NU-GR-
Increased aerobic capacity reduces susceptibility to acute highâfat dietâinduced weight gain
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/134165/1/oby21564.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/134165/2/oby21564_am.pd
Experimental demonstration of a squeezing enhanced power recycled Michelson interferometer for gravitational wave detection
Interferometric gravitational wave detectors are expected to be limited by
shot noise at some frequencies. We experimentally demonstrate that a power
recycled Michelson with squeezed light injected into the dark port can overcome
this limit. An improvement in the signal-to-noise ratio of 2.3dB is measured
and locked stably for long periods of time. The configuration, control and
signal readout of our experiment are compatible with current gravitational wave
detector designs. We consider the application of our system to long baseline
interferometer designs such as LIGO.Comment: 4 pages 4 figure
Noise parametric identification and whitening for LIGO 40-meter interferometer data
We report the analysis we made on data taken by Caltech 40-meter prototype
interferometer to identify the noise power spectral density and to whiten the
sequence of noise. We concentrate our study on data taken in November 1994, in
particular we analyzed two frames of data: the 18nov94.2.frame and the
19nov94.2.frame.
We show that it is possible to whiten these data, to a good degree of
whiteness, using a high order whitening filter. Moreover we can choose to
whiten only restricted band of frequencies around the region we are interested
in, obtaining a higher level of whiteness.Comment: 11 pages, 15 figures, accepted for publication by Physical Review
Detection, Measurement and Gravitational Radiation
Here I examine how to determine the sensitivity of the LIGO, VIRGO, and LAGOS
gravitational wave detectors to sources of gravitational radiation by
considering the process by which data are analyzed in a noisy detector. By
constructing the probability that the detector output is consistent with the
presence of a signal, I show how to (1) quantify the uncertainty that the
output contains a signal and is not simply noise, and (2) construct the
probability distribution that the signal parameterization has a certain value.
From the distribution and its mode I determine volumes in parameter
space such that actual signal parameters are in with probability . If
we are {\em designing} a detector, or determining the suitability of an
existing detector for observing a new source, then we don't have detector
output to analyze but are interested in the ``most likely'' response of the
detector to a signal. I exploit the techniques just described to determine the
``most likely'' volumes for detector output corresponding to the source.
Finally, as an example, I apply these techniques to anticipate the sensitivity
of the LIGO and LAGOS detectors to the gravitational radiation from a perturbed
Kerr black hole.Comment: 37 pages (plus 6 figures), LaTeX/REVTE
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