3,505 research outputs found
Electrical termination techniques
A technical review of high reliability electrical terminations for electronic equipment was made. Seven techniques were selected from this review for further investigation, experimental work, and preliminary testing. From the preliminary test results, four techniques were selected for final testing and evaluation. These four were: (1) induction soldering, (2) wire wrap, (3) percussive arc welding, and (4) resistance welding. Of these four, induction soldering was selected as the best technique in terms of minimizing operator errors, controlling temperature and time, minimizing joint contamination, and ultimately producing a reliable, uniform, and reusable electrical termination
The Nucleus of Comet 10P/Tempel 2 in 2013 and Consequences Regarding Its Rotational State: Early Science from the Discovery Channel Telescope
We present new lightcurve measurements of Comet 10P/Tempel 2 carried out with
Lowell Observatory's Discovery Channel Telescope in early 2013 when the comet
was at aphelion. These data represent some of the first science obtained with
this new 4.3-m facility. With Tempel 2 having been observed to exhibit a small
but ongoing spin-down in its rotation period for over two decades, our primary
goals at this time were two-fold. First, to determine its current rotation
period and compare it to that measured shortly after its most recent perihelion
passage in 2010, and second, to disentangle the spin-down from synodic effects
due to the solar day and the Earth's orbital motion and to determine the sense
of rotation, i.e. prograde or retrograde. At our midpoint of 2013 Feb 24, the
observed synodic period is 8.948+/-0.001 hr, exactly matching the predicted
prograde rotation solution based on 2010 results, and yields a sidereal period
of the identical value due to the solar and Earth synodic components just
canceling out during the interval of the 2013 observations. The retrograde
solution is ruled out because the associated sidereal periods in 2010 and 2013
are quite different even though we know that extremely little outgassing,
needed to produce torques, occurred in this interval. With a definitive sense
of rotation, the specific amounts of spin-down to the sidereal period could be
assessed. The nominal values imply that the rate of spin-down has decreased
over time, consistent with the secular drop in water production since 1988. Our
data also exhibited an unexpectedly small lightcurve amplitude which appears to
be associated with viewing from a large, negative sub-Earth latitude, and a
lightcurve shape deviating from a simple sinusoid implying a highly irregularly
shaped nucleus.Comment: Accepted by AJ; 12 pages of text (pre-print style), 3 tables, 2
figure
Analysis of total urinary catecholamines by liquid chromatography: methodology, routine experience and clinical interpretations of results
A simple routine method is described for simultaneous assay of total urinary adrenaline, noradrenaline and dopamine. The catecholamines are pre-purified on a small ion-exchange column, separated by reversed phase ion-pair liquid chromatography, and are quantitated by electrochemical detection. The method was routinely applied to 422 urines. Elevated values were found in four urine specimens obtained from patients with histologically proven phaeochromocytomas. Virtually no interference by endogenous or exogenous compounds was found. Values for urinary catecholamines determined by fluorimetric analysis agreed with those obtained by high pressure liquid chromatography with electrochemical detection. Within-day CVs for the compounds ranged from 5.2-11.9%, between-day CVs from 3.3-6.6%. The normal range (95% confidence level) was 20-230 micrograms/24 h for noradrenaline and 1-35 micrograms/24 h for adrenaline
Evaluation of a Cognitive-Behavioral Mood Management Intervention for Depressed College Smokers
College smoking correlates positively with depressive symptoms, and given the relation between smoking and mood regulation, cigarette smoking is a major health concern among depressed college smokers. This randomized clinical trial examined smoking reduction and cessation among college smokers with elevated depressive symptoms participating in a group-based multi-component intervention including mood management, behavioral counseling, and motivational enhancement (CBT). Fifty-eight smokers (smoked 6 or more days in the past 30) were randomized to six sessions of the experimental intervention (n = 29) or a nutrition-focused attention-matched control group (CG; n = 29). Relative to CG participants, a significantly greater proportion of CBT participants reduced smoking intensity by 50 percent or more at end of treatment. In addition, confidence to reduce smoking increased significantly among CBT participants and decreased among CG participants from baseline to end of treatment. Overall, CBT participants maintained these changes at 3-month follow-up even though group differences were no longer statistically significant. Study findings demonstrate the feasibility of this intervention and support its utility for smoking reduction among depressed college students
Like Uber, but for Local Government Law: The Future of Local Regulation of the Sharing Economy
In the past five years, sharing economy firms like Uber, Zipcar, Airbnb and TaskRabbit have generated both huge market valuations and fierce regulatory contests in America\u27s cities. Incumbent firms in the taxi, hotel, and other industries, as well as consumer protection, labor, and neighborhood activists, have pushed for regulations stifling or banning new sharing economy entrants. Sharing firms have fought back, using their popularity with consumers and novel political strategies, lobbying for freedom to operate as broadly as possible without government interference. But to date, both participants and observers of these sharing wars have relied on an unstated assumption: if the sharing firms win these fights, their future will be largely free from government regulation. Local governments will either shut sharing down, or they will leave it alon
Effect of pressure on the partial equivalent volume of salts in seawater
The effect of pressure on the partial equivalent volumes of salts of the major ions in 35%, seawater at 10 and 25°C was determined for applied pressures of 400 and 1000 bars from measurements of the change in solution compression with salt concentration...
Like Uber, but for Local Government Law: The Future of Local Regulation of the Sharing Economy
In the past five years, sharing economy firms like Uber, Zipcar, Airbnb and TaskRabbit have generated both huge market valuations and fierce regulatory contests in America\u27s cities. Incumbent firms in the taxi, hotel, and other industries, as well as consumer protection, labor, and neighborhood activists, have pushed for regulations stifling or banning new sharing economy entrants. Sharing firms have fought back, using their popularity with consumers and novel political strategies, lobbying for freedom to operate as broadly as possible without government interference. But to date, both participants and observers of these sharing wars have relied on an unstated assumption: if the sharing firms win these fights, their future will be largely free from government regulation. Local governments will either shut sharing down, or they will leave it alon
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