Voltage regulator dissipates minimal power and functions as a voltage divider

Regulator requires minimum amount of power for voltage division and it is not required continuously. The only power loss, except for regulating purposes, is that needed to provide for imbalances in load current requirements. For balanced loads, only leakage current flows through regulating transistors

03/05/1948 Letter from the Lewiston High School Band Booster Club

Letter from Hester B. Hunter, Ticket Committee of the Lewiston High School Band Booster Club, to Louis-Philippe Gagné.https://digitalcommons.usm.maine.edu/fac-lpg-letters-1948-01-06/1016/thumbnail.jp

Break up of returning plasma after the 7 June 2011 filament eruption by Rayleigh-Taylor instabilities

A prominence eruption on 7 June 2011 produced spectacular curtains of plasma falling through the lower corona. At the solar surface they created an incredible display of extreme ultraviolet brightenings. The aim is to identify and analyze some of the local instabilities which produce structure in the falling plasma. The structures were investigated using SDO/AIA 171A and 193A images in which the falling plasma appeared dark against the bright coronal emission. Several instances of the Rayleigh-Taylor instability were investigated. In two cases the Alfven velocity associated with the dense plasma could be estimated from the separation of the Rayleigh-Taylor fingers. A second type of feature, which has the appearance of self-similar branching horns, is also discussed.Comment: 6 pages, 7 figures, submitted A&A. Movies are at http://www.mps.mpg.de/data/outgoing/innes/arcs_movie.avi and http://www.mps.mpg.de/data/outgoing/innes/horns_movie.av

Electronic controller for reciprocating rotary crystallizer

An electronic controller for a reciprocating rotary crystallizer is described. The heart of this system is the electronic timer circuit. A schematic along with a detailed description of its operation is given

Going Negative: The Next Horizon in Climate Engineering Law

As the global community struggles to turn the Paris Agreement’s commitments into meaningful emission reductions and the United States turbulently reverses its climate policies, the potential role of “negative emissions technologies” and other climate engineering approaches is drawing increasingly serious attention. These technologies are engineering on the grandest scale: climate engineering seeks to offset the effects of anthropogenic climate change by either altering the solar radiation reaching the earth’s surface or changing the composition of the atmosphere itself. Specifically, negative emissions technologies would directly remove greenhouse gases (GHGs) from the ambient air and help to remove accumulated atmospheric carbon dioxide (CO2) caused by historical emissions. After over a decade of debate, substantive research and planning associated with negative emissions technologies and solar radiation management have begun to inch forward. But this movement is happening in unexpected ways, and some of the most important decisions and commitments are occurring outside of the spotlight

The Colha Preceramic Project: A Status Report

Latin American Studie

Proper Motions of PSRs B1757-24 and B1951+32: Implications for Ages and Associations

Over the last decade, considerable effort has been made to measure the proper motions of the pulsars B1757-24 and B1951+32 in order to establish or refute associations with nearby supernova remnants and to understand better the complicated geometries of their surrounding nebulae. We present proper motion measurements of both pulsars with the Very Large Array, increasing the time baselines of the measurements from 3.9 yr to 6.5 yr and from 12.0 yr to 14.5 yr, respectively, compared to previous observations. We confirm the non-detection of proper motion of PSR B1757-24, and our measurement of (mu_a, mu_d) = (-11 +/- 9, -1 +/- 15) mas yr^{-1} confirms that the association of PSR B1757-24 with SNR G5.4-1.2 is unlikely for the pulsar characteristic age of 15.5 kyr, although an association can not be excluded for a significantly larger age. For PSR B1951+32, we measure a proper motion of (mu_a, mu_d) = (-28.8 +/- 0.9, -14.7 +/- 0.9) mas yr^{-1}, reducing the uncertainty in the proper motion by a factor of two compared to previous results. After correcting to the local standard of rest, the proper motion indicates a kinetic age of ~51 kyr for the pulsar, assuming it was born near the geometric center of the supernova remnant. The radio-bright arc of emission along the pulsar proper motion vector shows time-variable structure, but moves with the pulsar at an approximately constant separation ~2.5", lending weight to its interpretation as a shock structure driven by the pulsar.Comment: LaTeX file uses emulateapj.cls; 7 pages, 4 figures, to be published ApJ February 10, 2008, v674 p271-278. Revision reflects journal formatting; there are no substantial revision

Learning from Errors: Error-Related Neural Activity Predicts Improvements in Future Inhibitory Control Performance

Failure to adapt performance following an error is a debilitating symptom of many neurological and psychiatric conditions. Healthy individuals readily adapt their behavior in response to an error, an ability thought to be subserved by the posterior medial frontal cortex (pMFC). However, it remains unclear how humans adaptively alter cognitive control behavior when they reencounter situations that were previously failed minutes or days ago. Using functional magnetic resonance imaging, we examined neural activity during a Go/No-go response inhibition task that provided the opportunity for participants to learn from their errors. When they failed to inhibit their response, they were shown the same target stimulus during the next No-go trial, which itself could occur up to 20 trials after its initial presentation. Activity within the pMFC was significantly greater for initial errors that were subsequently corrected than for errors that were repeated later in the display sequence. Moreover, pMFC activity during errors predicted future responses despite a sizeable interval (on average 12 trials) between an error and the next No-go stimulus. Our results indicate that changes in cognitive control performance can be predicted using error-related activity. The increased likelihood of adaptive changes occurring during periods of recent success is consistent with models of error-related activity that argue for the influence of outcome expectancy (Holroyd and Coles, 2002; Brown and Braver, 2005). The findings may also help to explain the diminished error-related neural activity in such clinical conditions as schizophrenia, as well as the propensity for perseverative behavior in these clinical groups

VLBI imaging of a flare in the Crab Nebula: More than just a spot

We report on very long baseline interferometry (VLBI) observations of the radio emission from the inner region of the Crab Nebula, made at 1.6 GHz and 5 GHz after a recent high-energy flare in this object. The 5 GHz data have provided only upper limits of 0.4 milli-Jansky (mJy) on the flux density of the pulsar and 0.4 mJy/beam on the brightness of the putative flaring region. The 1.6 GHz data have enabled imaging the inner regions of the nebula on scales of up to ~40". The emission from the inner "wisps" is detected for the first time with VLBI observations. A likely radio counterpart (designated "C1") of the putative flaring region observed with Chandra and HST is detected in the radio image, with an estimated flux density of $0.5\pm 0.3$\,mJy and a size of 0.2-0.6". Another compact feature ("C2") is also detected in the VLBI image closer to the pulsar, with an estimated flux density of 0.4 +- 0.2 mJy and a size smaller than 0{\farcs}2. Combined with the broad-band SED of the flare, the radio properties of C1 yield a lower limit of ~0.5 mG for the magnetic field and a total minimum energy of 1.2*10^41 ergs vested in the flare (corresponding to using about 0.2% of the pulsar spin-down power). The 1.6 GHz observations provide upper limits for the brightness (0.2 mJy/beam) and total flux density (0.4 mJy) of the optical Knot 1 located at 0.6" from the pulsar. The absolute position of the Crab pulsar is determined, and an estimate of the pulsar proper motion is obtained.Comment: Astronomy & Astrophysics; accepted; 10 pages, 8 figure