45,977 research outputs found
Very high speed direct-readout, control and recording system
Characteristics of electronic system for high speed readout, control, and recording of data are discussed. Operation of system is described to show rate of data processing and accuracy obtainable. Primary advantage of system is providing direct recording of parameter value several times per second
Measurement system
A measurement system is described for providing an indication of a varying physical quantity represented by or converted to a variable frequency signal. Timing pulses are obtained marking the duration of a fixed number, or set, of cycles of the sampled signal and these timing pulses are employed to control the period of counting of cycles of a higher fixed and known frequency source. The counts of cycles obtained from the fixed frequency source provide a precise measurement of the average frequency of each set of cycles sampled, and thus successive discrete values of the quantity being measured. The frequency of the known frequency source is made such that each measurement is presented as a direct digital representation of the quantity measured
Building Social Movement Unionism: The Transformation of the American Labor Movement
[Excerpt] In the United States, the renewed energy displayed by the labor movement is particularly promising. From organizing drives to strike victories to legislative campaigns, labor\u27s renewed influence in the American political economy is clearly seen. A labor movement that was left for dead by many in the Reagan era has developed new leadership and innovative strategies for rank-and-file mobilization and political clout. In a global economy dominated to a large extent by American-based multinational corporations, the world needs a strong American labor movement. The goal of the new activists, young and old, who drive today\u27s labor campaigns, is the rebirth of modernized, mobilized, powerful American unions.
We suggest that innovations at the heart of the current revitalization are part of a broad shift away from traditional postwar unionism to a new social movement unionism. The transformation occurs in a weak institutional context in which experimentation and innovation are possible. Driving the change are two generations of activists: veterans of the social movements of the 1960s, now in leadership positions at the American Federation of Labor-Congress of Industrial Organizations (AFL-CIO) and in many member unions, and a new generation of campus and workplace activists
Maxometers (peak wind speed anemometers)
An instrument for measuring peak wind speeds under severe environmental conditions is described, comprising an elongated cylinder housed in an outer casing. The cylinder contains a piston attached to a longitudinally movable guided rod having a pressure disk mounted on one projecting end. Wind pressure against the pressure disk depresses the movable rod. When the wind reaches its maximum speed, the rod is locked by a ball clutch mechanism in the position of maximum inward movement. Thereafter maximum wind speed or pressure readings may be taken from calibrated indexing means
Alessi 95 and the short period Cepheid SU Cassiopeiae
The parameters for the newly-discovered open cluster Alessi 95 are
established on the basis of available photometric and spectroscopic data, in
conjunction with new observations. Colour excesses for
spectroscopically-observed B and A-type stars near SU Cas follow a reddening
relation described by E(U-B)/E(B-V)=0.83+0.02*E(B-V), implying a value of
R=Av/E(B-V)~2.8 for the associated dust. Alessi 95 has a mean reddening of
E(B-V)_(B0)=0.35+-0.02 s.e., an intrinsic distance modulus of Vo-Mv=8.16+-0.04
s.e. (+-0.21 s.d.), d=429+-8 pc, and an estimated age of 10^8.2 yr from ZAMS
fitting of available UBV, CCD BV, NOMAD, and 2MASS JHKs observations of cluster
stars. SU Cas is a likely cluster member, with an inferred space reddening of
E(B-V)=0.33+-0.02 and a luminosity of =-3.15+-0.07 s.e., consistent with
overtone pulsation (P_FM=2.75 d), as also implied by the Cepheid's light curve
parameters, rate of period increase, and Hipparcos parallaxes for cluster
stars. There is excellent agreement of the distance estimates for SU Cas
inferred from cluster ZAMS fitting, its pulsation parallax derived from the
infrared surface brightness technique, and Hipparcos parallaxes, which all
agree to within a few percent.Comment: Accepted for Publication (MNRAS
On the Form of the Spitzer Leavitt Law and its Dependence on Metallicity
The form and metallicity-dependence of Spitzer mid-infrared Cepheid relations
are a source of debate. Consequently, Spitzer 3.6 and 4.5 um period-magnitude
and period-color diagrams were re-examined via robust routines, thus providing
the reader an alternative interpretation to consider. The relations (nearly
mean-magnitude) appear non-linear over an extensive baseline (0.45< logPo
<2.0), particularly the period-color trend, which to first-order follows
constant (3.6-4.5) color for shorter-period Cepheids and may transition into a
bluer convex trough at longer-periods. The period-magnitude functions can be
described by polynomials (e.g., [3.6 um]=Ko-(3.071+-0.059)
logPo-(0.120+-0.032)logPo^2), and Cepheid distances computed using 3.6 and 4.5
um relations agree and the latter provides a first-order consistency check (CO
sampled at 4.5 um does not seriously compromise those distances). The
period-magnitude relations appear relatively insensitive to metallicity
variations ([Fe/H]~0 to -0.75), a conclusion inferred partly from comparing
galaxy distances established from those relations and NED-D (n>700), yet a
solid conclusion awaits comprehensive mid-infrared observations for metal-poor
Cepheids in IC 1613 ([Fe/H] -1). The Cepheid-based distances were corrected for
dust obscuration using a new ratio (i.e., A(3.6)/E(B-V)=0.18+-0.06) deduced
from GLIMPSE (Spitzer) data.Comment: To appear in Ap
Industry views on water resources planning methods – prospects for change in England and Wales
This paper describes a qualitative study of practitioner perspectives on regulated water resources planning practice in England and Wales. The study focuses on strengths and weaknesses of existing practice and the case for change towards a risk-based approach informed by stochastic modelling assessments. In-depth, structured interviews were conducted to capture the views of planners, regulators and consultants closely involved in the planning process. We found broad agreement that the existing water availability assessment methods are fallible; they lack transparency, are often highly subjective and may fail to adequately expose problems of resilience. While most practitioners believe these issues warrant a more detailed examination of risk in the planning process, few believe there is a strong case for a fundamental shift towards risk-based planning informed by stochastic modelling assessments. The study identifies perceived business risks associated with change and exposes widespread scepticism of stochastic methods
Numerical investigations of linear least squares methods for derivative estimation
The results of a numerical investigation into the errors for least squares estimates of function gradients are presented. The underlying algorithm is obtained by constructing a least squares problem using a truncated Taylor expansion. An error bound associated with this method contains in its numerator terms related to the Taylor series remainder, while its denominator contains the smallest singular value of the least squares matrix. Perhaps for this reason the error bounds are often found to be pessimistic by several orders of magnitude. The circumstance under which these poor estimates arise is elucidated and an empirical correction of the theoretical error bounds is conjectured and investigated numerically. This is followed by an indication of how the conjecture is supported by a rigorous argument
Fertility building strategies during the conversion period – assessment of performance in a stockless field vegetable rotation
This report was presented at the UK Organic Research 2002 Conference of the Colloquium of Organic Researchers (COR). Nutrient off-takes, residue returns and nutrient inputs were measured during and after conversion from a conventional arable system to organic vegetables with cereals. This data was used to construct nutrient budgets to assess the effectiveness of contrasting fertility building strategies and various cropping regimes. The effect of placing the cereal crops in different places in the crop sequence was also considered
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