5,327 research outputs found
Design and manufacture of direct current torquer amplifiers Final summary report
Design and manufacture of direct current torquer amplifier with pulse width modulation circui
Effects of Irrigation on an Adjoining Ranch Economy
To determine whether irrigation development in western South Dakota is economically worthwhile, one must consider the stabilization effects it would have on the ranching economy of the area. Irrigation development is going forward. The Angostura Unit on the Cheyenne River is now partially irrigated. Additional water for the long established Belle Fourche Project has been made available from the Keyhole Dam in Wyoming. The Bureau of Reclamation has extensive plans for pump irrigation along the Missouri River and its tributaries. The Oahe Dam is under construction. Proposed irrigation of 750,000 acres from water impounded by this dam greatly overshadows all previous irrigation developments in South Dakota. The Shadehill Dam on the Grand River has been completed. Investigations to determine the feasibility of irrigation in the Oahe area and from Shadehill Dam are under way. These developments require large outlays of public funds, and their effects touch not only the people in the area but their neighbors, the state, and the nation. In western South Dakota less than 10 percent of the farms and ranches have some irrigation, according to the 1950 Census of Agriculture. Some of this land is irrigated from streams, small private reservoirs, or wells. Other land is irrigated by water made available by large government-sponsored irrigation developments such as the Belle Fourche project. A few farmers and ranchers have feed bases on such projects even though their main unit is some miles away. But 90 percent of the operators in western South Dakota have no irrigation
Simple models for the shuttle remote manipulator system
The investigation is aimed at establishing a series of simple models which can be used to study the forces and moments which occur due to the reaction control system (RCS) jet plume firings during a deployment or retrieval of an IUS type payload. The models considered in this investigation are primarily planar in nature. In this study primary attention is given to the roles the payload play in determining the overall moments on the remote manipulator system arm
Beyond Dependency: Strategies for Saving Foundations
We have generally tried to depend on the force of argument to win the day against the structural forces that have driven this decline. Yet foundations generally operates from a position of relative weakness in schools of education: we provide service to programs but generally do not have our own strong programs. We “take” enrollment from other departments, but do not “give” enrollment to them or bring independent enrollment to the school. This leaves foundations in a position of dependency. The core argument of this paper is that we need to move beyond dependency toward a vision of foundations as, at least in part, a provider of robust (if collaborative) programs of its own, and we discuss a range of strategies designed to foster the development of such programs. Amidst the current environment, we believe that foundations will find it increasingly difficult to make our arguments stick without the associated power to make ourselves heard
The response of interferometric gravitational wave detectors
The derivation of the response function of an interferometric gravitational
wave detector is a paradigmatic calculation in the field of gravitational wave
detection. Surprisingly, the standard derivation of the response wave detectors
makes several unjustifiable assumptions, both conceptual and quantitative,
regarding the coordinate trajectory and coordinate velocity of the null
geodesic the light travels along. These errors, which appear to have remained
unrecognized for at least 35 years, render the "standard" derivation inadequate
and misleading as an archetype calculation. Here we identify the flaws in the
existing derivation and provide, in full detail, a correct derivation of the
response of a single-bounce Michelson interferometer to gravitational waves,
following a procedure that will always yield correct results; compare it to the
"standard", but incorrect, derivation; show where the earlier mistakes were
made; and identify the general conditions under which the "standard" derivation
will yield correct results. By a fortuitous set of circumstances, not generally
so, the final result is the same in the case of Minkowski background spacetime,
synchronous coordinates, transverse-traceless gauge metric perturbations, and
arm mirrors at coordinate rest.Comment: 10 pages, one figure, as accepted to PR
A stochastic template placement algorithm for gravitational wave data analysis
This paper presents an algorithm for constructing matched-filter template
banks in an arbitrary parameter space. The method places templates at random,
then removes those which are "too close" together. The properties and
optimality of stochastic template banks generated in this manner are
investigated for some simple models. The effectiveness of these template banks
for gravitational wave searches for binary inspiral waveforms is also examined.
The properties of a stochastic template bank are then compared to the
deterministically placed template banks that are currently used in
gravitational wave data analysis.Comment: 14 pages, 11 figure
A new numerical method to construct binary neutron star initial data
We present a new numerical method for the generation of binary neutron star
initial data using a method along the lines of the the Wilson-Mathews or the
closely related conformal thin sandwich approach. Our method uses six different
computational domains, which include spatial infinity. Each domain has its own
coordinates which are chosen such that the star surfaces always coincide with
domain boundaries. These properties facilitate the imposition of boundary
conditions. Since all our fields are smooth inside each domain, we are able to
use an efficient pseudospectral method to solve the elliptic equations
associated with the conformal thin sandwich approach. Currently we have
implemented corotating configurations with arbitrary mass ratios, but an
extension to arbitrary spins is possible. The main purpose of this paper is to
introduce our new method and to test our code for several different
configurations.Comment: 18 pages, 8 figures, 1 tabl
The equivalence principle, uniformly accelerated reference frames, and the uniform gravitational field
The relationship between uniformly accelerated reference frames in flat
spacetime and the uniform gravitational field is examined in a relativistic
context. It is shown that, contrary to previous statements in the pages of this
journal, equivalence does not break down in this context. No restrictions to
Newtonian approximations or small enclosures are necessary
Removing non-stationary, non-harmonic external interference from gravitational wave interferometer data
We describe a procedure to identify and remove a class of non-stationary and
non-harmonic interference lines from gravitational wave interferometer data.
These lines appear to be associated with the external electricity main
supply, but their amplitudes are non-stationary and they do not appear at
harmonics of the fundamental supply frequency. We find an empirical model able
to represent coherently all the non-harmonic lines we have found in the power
spectrum, in terms of an assumed reference signal of the primary supply input
signal. If this signal is not available then it can be reconstructed from the
same data by making use of the coherent line removal algorithm that we have
described elsewhere. All these lines are broadened by frequency changes of the
supply signal, and they corrupt significant frequency ranges of the power
spectrum. The physical process that generates this interference is so far
unknown, but it is highly non-linear and non-stationary. Using our model, we
cancel the interference in the time domain by an adaptive procedure that should
work regardless of the source of the primary interference. We have applied the
method to laser interferometer data from the Glasgow prototype detector, where
all the features we describe in this paper were observed. The algorithm has
been tuned in such a way that the entire series of wide lines corresponding to
the electrical interference are removed, leaving the spectrum clean enough to
detect signals previously masked by them. Single-line signals buried in the
interference can be recovered with at least 75 % of their original signal
amplitude.Comment: 14 pages, 5 figures, Revtex, psfi
Economics of Federal Irrigation Projects in the Missouri Basin
A greatly expanded Federal program for irrigation development is planned for the Missouri Basin. Under the Flood Control Act of 1944, nearly 5 million acres were proposed for irrigation; and in addition, about half a million acres under irrigation were to receive supplemental water. Nearly one-half of the new irrigation planned was to be located in North and South Dakota. The Missouri-Souris Unit in North Dakota of more than a million acres and the Oahe Unit in South Dakota of three-quarter million acres are the two largest under consideration. Both units are receiving further study to determine the suitability of the soils for irrigation. The irrigation facilities in the Missouri The irrigation facilities in the Missouri Basin would be built and financed largely by the Federal Government. Consequently, certain questions concerning evaluation, accounting of costs, allocations of costs to various purposes, repayments by beneficiaries and similar questions are of public interest. No less important are factors such as the suitability of soils for irrigation, adequacy of water supplies, repayment capacity and related farm problems. However, much less information has been available to the public on some of the over-all economic aspects of the proposed development, and these are the concern of this report. While it is recognized that there are important benefits from irrigation, these are not taken up here because they have been discussed in other reports. (See more in text
- …