2,661 research outputs found
Three computer codes to read, plot and tabulate operational test-site recorded solar data
Computer programs used to process data that will be used in the evaluation of collector efficiency and solar system performance are described. The program, TAPFIL, reads data from an IBM 360 tape containing information (insolation, flowrates, temperatures, etc.) from 48 operational solar heating and cooling test sites. Two other programs, CHPLOT and WRTCNL, plot and tabulate the data from the direct access, unformatted TAPFIL file. The methodology of the programs, their inputs, and their outputs are described
Development of a rotating gravity gradiometer for earth orbit applications (AAFE)
Some preliminary mission studies are described along with the design, fabrication, and test of a breadboard model of an earth orbital, rotating gravity gradiometer with a design goal of 10 to the minus 11th power/sec sq (0.01 EU) in a 35-sec integration time. The proposed mission uses a Scout vehicle to launch one (or two orthogonally oriented) spin-stabilized satellites into a 330-km circular polar orbit some 20 days before an equinox. During the short orbital lifetime, the experiment would obtain two complete maps of the gravity gradient field with a resolution approaching 270 km (degree 75). The breadboard model of the gradiometer demonstrated a combined thermal and electronic noise threshold of 0.015 EU per data channel. The design changes needed to reduce the noise to less than 0.01 EU were identified. Variations of the sensor output signal with temperature were experimentally determined and a suitable method of temperature compensation was developed and tested. Other possible error sources, such as sensor interaction with satellite dynamics and magnetic fields, were studied analytically and shown to be small
A Project to Develop Genetic Specification for the Beef Industry
A new beef breeding project will be conducted at the Rhodes and McNay farms of ISU. The project will use the field data of the American Angus Association along with the research resources (cattle) of the farms to study questions that will enhance the genetic investigations using the field data. It will build on the expertise developed at ISU with ultrasound to measure body composition in the live animal and in the carcass. Two selection lines, using registered Angus obtained as heifers and through ET, of 200 females each will be selected for increased intramuscular fat (Q line) and for increased retail product (R line). The estimation of the genetic correlation between quality and amount of product can best be accomplished through the study of one generation of selection using measures of body composition derived from ultrasound. A progeny test herd will be maintained to evaluate all sires used through progeny carcass testing and to further research with ultrasound. The project will study efficiency of body maintenance. Results will be shared through the Beef Improvement Federation to benefit all producers in the development of sound programs to profitably produce specified beef products
Flux amplification using stochastic superconducting quantum interference devices
This is the published version, also available here: http://dx.doi.org/10.1063/1.114161.The flux change δ Φ through a bistable superconducting quantum interference device has been measured in the presence of thermally induced switching (with rate Γ) versus δ Φ x , the change in the applied flux. For small δ Φ x , δ Φ is proportional to δ Φ x with a measured flux gain g, depending on the temperature, barrier height, and frequency Ω, with a maximum of about 16. In agreement with theories of periodically driven stochastic bistable systems,g(Ω) is nearly frequency independent up to Γ and is proportional to Ω−1 for Ω≫Γ. For larger amplitude signals, harmonic generation has been measured in the adiabatic limit (Ω≪Γ) and found to be in good agreement with theory. Possible applications of this system for flux measurement are discussed
Human prostate specific and shared differentiation antigens defined by monoclonal antibodies.
Phenology satellite experiment
There are no author-identified significant results in this report
The Positivity of Energy for Asymptotically Anti-de Sitter Spacetimes
We use the formulation of asymptotically anti-de Sitter boundary conditions
given by Ashtekar and Magnon to obtain a coordinate expression for the general
asymptotically AdeS metric in a neighbourhood of infinity. From this, we are
able to compute the time delay of null curves propagating near infinity. If the
gravitational mass is negative, so will be the time delay (relative to null
geodesics at infinity) for certain null geodesics in the spacetime. Following
closely an argument given by Penrose, Sorkin, and Woolgar, who treated the
asymptotically flat case, we are then able to argue that a negative time delay
is inconsistent with non-negative matter-energies in spacetimes having good
causal properties. We thereby obtain a new positive mass theorem for these
spacetimes. The theorem may be applied even when the matter flux near the
boundary-at-infinity falls off so slowly that the mass changes, provided the
theorem is applied in a time-averaged sense. The theorem also applies in
certain spacetimes having local matter-energy that is sometimes negative, as
can be the case in semi-classical gravity.Comment: (Plain TeX - figures not included
Neural Network Application for Classifying Beef Intramuscular Fat Percentage
In the previous report, we have presented statistical pattern recognition and classification techniques to preclassify the ultrasonic images into the low- or high- IFAT groups (less than 8% and more than 8%). The classification tree was used in the previous report, and it provided overall classification accuracy of 90% for low- and high- IFAT groups of images. Here, we are presenting artificial neural network (ANN) as a pattern recognition tool to get better classification accuracy. ANNs provide a nonparametric approach for the nonlinear estimation of data. These models are trained to mimic the desired behavior using example data from the actual problem. The ANN model provided classification accuracy of 95% for 653 sample images
Scaling dependence on the fluid viscosity ratio in the selective withdrawal transition
In the selective withdrawal experiment fluid is withdrawn through a tube with
its tip suspended a distance S above a two-fluid interface. At sufficiently low
withdrawal rates, Q, the interface forms a steady state hump and only the upper
fluid is withdrawn. When Q is increased (or S decreased), the interface
undergoes a transition so that the lower fluid is entrained with the upper one,
forming a thin steady-state spout. Near this transition the hump curvature
becomes very large and displays power-law scaling behavior. This scaling allows
for steady-state hump profiles at different flow rates and tube heights to be
scaled onto a single similarity profile. I show that the scaling behavior is
independent of the viscosity ratio.Comment: 33 Pages, 61 figures, 1 tabl
Rouse Chains with Excluded Volume Interactions: Linear Viscoelasticity
Linear viscoelastic properties for a dilute polymer solution are predicted by
modeling the solution as a suspension of non-interacting bead-spring chains.
The present model, unlike the Rouse model, can describe the solution's
rheological behavior even when the solvent quality is good, since excluded
volume effects are explicitly taken into account through a narrow Gaussian
repulsive potential between pairs of beads in a bead-spring chain. The use of
the narrow Gaussian potential, which tends to the more commonly used
delta-function repulsive potential in the limit of a width parameter "d" going
to zero, enables the performance of Brownian dynamics simulations. The
simulations results, which describe the exact behavior of the model, indicate
that for chains of arbitrary but finite length, a delta-function potential
leads to equilibrium and zero shear rate properties which are identical to the
predictions of the Rouse model. On the other hand, a non-zero value of "d"
gives rise to a prediction of swelling at equilibrium, and an increase in zero
shear rate properties relative to their Rouse model values. The use of a
delta-function potential appears to be justified in the limit of infinite chain
length. The exact simulation results are compared with those obtained with an
approximate solution which is based on the assumption that the non-equilibrium
configurational distribution function is Gaussian. The Gaussian approximation
is shown to be exact to first order in the strength of excluded volume
interaction, and is found to be accurate above a threshold value of "d", for
given values of chain length and strength of excluded volume interaction.Comment: Revised version. Long chain limit analysis has been deleted. An
improved and corrected examination of the long chain limit will appear as a
separate posting. 32 pages, 9 postscript figures, LaTe
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