3,151 research outputs found
Sediment management for Southern California mountains, coastal plains and shoreline
The Environmental Quality Laboratory at Caltech and the Shore
Processes Laboratory at Scripps Institution of Oceanography have jointly
undertaken a study of regional sediment balance problems in coastal
southern California (see map in Figure 1). The overall objective in
this study is to define specific alternatives in sediment management that
may be implemented to alleviate a) existing sediment imbalance problems
(e.g. inland debris disposal, local shoreline erosion) and b) probable
future problems that have not yet manifested themselves. These
alternatives will be identified through a consideration of economic,
legal, and institutional issues as well as an analysis of governing
physical processes and engineering constraints.
The first part of this study (Phase I), which is currently under
way, involves a compilation and analysis of all available data in
an effort to obtain an accurate definition of the inland/coastal
regional sediment balance under natural conditions, and specific
quantitative effects man-made controls have on the overall natural process.
During FY77, substantial progress was made at EQL and SPL in
achieving the objectives of the initial Planning and Assessment Phase
of the CIT/SIO Sediment Management Project. Financial support came
from Los Angeles County, U.S. Geological Survey, Orange County,
U.S. Army Corps of Engineers, and discretionary funding provided by
a grant from the Ford Foundation. The current timetable for completion
of this phase is Fall 1978.
This report briefly describes the project status, including
general administration, special activities, and research work as of
January 1978
Characterization of a spheromak plasma gun: The effect of refractory electrode coatings
In order to investigate the proposition that high-Z impurities are responsible for the anomalously short lifetime of the Caltech spheromak, the center electrode of the spheromak plasma gun has been coated with a variety of metals (bare steel, copper, nickel, chromium, rhodium, and tungsten). Visible light (230–890 nm) emitted directly from the plasma in the gun breech was monitored for each of the coated electrodes. Plasma density and temperature and spheromak lifetime were compared for each electrode. Results indicate little difference in gun performance or macroscopic plasma parameters. The chromium and tungsten electrodes performed marginally better in that a previously reported helicity injection effect [Phys. Rev. Lett. 64, 2144 (1990)] is only observed in discharges using these electrode coatings. There are subtle differences in the detailed line emission spectra from the different electrodes, but the spectra are remarkably similar. The fact that (1) contrary to expectations, attempts to reduce high-Z impurities had only marginal effect on the spheromak lifetime coupled with (2) an estimate of Zeff<2 based on a 0-D model suggests that it is not impurities but some other mechanism that limits the lifetime of small, cold spheromaks. We will discuss the general characteristics of the spheromak gun as well as effects due to the coatings
Sediment Management for Southern California Mountians, Coastal Plains and Shoreline. Part D: Special Inland Studies
In southern California the natural environmental system involves the continual relocation of sedimentary materials. Particles are eroded from inland areas where there is sufficient relief and, precipitation. Then, with reductions in hydraulic gradient along the stream course and at the shoreline, the velocity of surface runoff is reduced and there is deposition. Generally, coarse sand, gravel and larger particles are deposited near the base of the eroding surfaces (mountains and hills) and the finer sediments are deposited on floodplains, in bays or lagoons, and at the shoreline as delta deposits. Very fine silt and clay particles, which make up a significant part of the eroded material, are carried offshore where they eventually deposit in deeper areas. Sand deposited at the shoreline is gradually moved along the coast by waves and currents, and provides nourishment for local beaches. However, eventually much of this littoral material is also lost to offshore areas. Human developments in the coastal region have substantially altered the natural sedimentary processes, through changes in land use, the harvesting of natural resources (logging, grazing, and sand and gravel mining); the construction and operation of water conservation facilities and flood control structures; and coastal developments. In almost all cases these developments have grown out of recognized needs and have well served their primary purpose. At the time possible deleterious effects on the local or regional sediment balance were generally unforeseen or were felt to be of secondary importance. In 1975 a large-scale study of inland and coastal sedimentation processes in southern California was initiated by the Environmental Quality Laboratory at the California Institute of Technology and the Center for Coastal Studies at Scripps Institution of Oceanography. This volume is one of a series of reports from this study. Using existing data bases, this series attempts to define quantitatively inland and coastal sedimentation processes and identify the effects man has had on these processes. To resolve some issues related to long-term sediment management, additional research and data will be needed. In the series there are four Caltech reports that provide supporting studies for the summary report (EQL Report No. 17). These reports include: EQL Report 17-A Regional Geological History EQL Report 17-B Inland Sediment Movements by Natural Processes EQL Report 17-C Coastal Sediment Delivery by Major Rivers in Southern California EQL Report 17-D -- Special Inland Studies Additional supporting reports on coastal studies (shoreline sedimentation processes, control structures, dredging, etc.) are being published by the Center for Coastal Studies at Scripps Institution of Oceanography, La Jolla, California
Neurophysiology
Contains reports on sixo research projects.National Institutes of Health (Grant 5 RO1 NB-04985-03)National Institutes of Health (Grant 5 RO1 NB-4897-03)National Institutes of Health (Grant NB-06251-01)U.S. Air Force (Office of Scientific Research) under Grant AF-AFOSR-880-65U.S. Air Force (Research and Technology Division) under Contract AF33(615)-1747The Teagle Foundation, Inc. (Grant)Bell Telephone Laboratories, Inc. (Grant)Instrumentation Laboratory under the auspices of DSR Project 55-257Bioscience Division of National Aeronautics and Space Administratio
Entropy generation in 2+1-dimensional Gravity
The tunneling approach, for entropy generation in quantum gravity, is shown
to be valid when applied to 3-D general relativity. The entropy of de Sitter
and Reissner-Nordstr\"om external event horizons and of the 3-D black hole
obtained by Ba\~nados et. al. is rederived from tunneling of the metric to
these spacetimes. The analysis for spacetimes with an external horizon is
carried out in a complete analogy with the 4-D case. However, we find
significant differences for the black hole. In particular the initial
configuration that tunnels to a 3-D black hole may not to yield an infinitely
degenerate object, as in 4-D Schwarzschild black hole. We discuss the possible
relation to the evaporation of the 3-D black hole.Comment: 22 pages, Tex, TAUP-2102-9
Many worlds in one
A generic prediction of inflation is that the thermalized region we inhabit
is spatially infinite. Thus, it contains an infinite number of regions of the
same size as our observable universe, which we shall denote as \O-regions. We
argue that the number of possible histories which may take place inside of an
\O-region, from the time of recombination up to the present time, is finite.
Hence, there are an infinite number of \O-regions with identical histories up
to the present, but which need not be identical in the future. Moreover, all
histories which are not forbidden by conservation laws will occur in a finite
fraction of all \O-regions. The ensemble of \O-regions is reminiscent of
the ensemble of universes in the many-world picture of quantum mechanics. An
important difference, however, is that other \O-regions are unquestionably
real.Comment: 9 pages, 2 figures, comments and references adde
MISSION ENGINEERING FOR HYBRID FORCE 2025
This report focuses on the mission engineering process for a hybrid force in 2025. Updated tasking from OPNAV N9I emphasized the necessity of focusing on the benefits of using cost-conservative unmanned systems. Specifically, the focus was placed on the near-peer competitor China and the problems that could be expected in an anti-access/area denial (A2/AD) situation in the South China Sea. The Naval Surface Warfare Center mission engineering approach was used to identify specific vignettes for proposed alternative fleet architectures and then analyzed using combat simulation and optimization models. Research on performance characteristics and cost were compiled on current unmanned systems, specifically those in development at a high technology readiness level. Proposed unmanned systems architectures were developed as solutions to the A2/AD problem and proposed vignettes. The unmanned systems architectures were then run through an optimization model to maximize system performance while minimizing cost. The results of the architecture optimization were then input into modeling and simulation. The overall effectiveness of each architecture in each vignette were then compared to find the most effective solution. An analysis of the results was performed to show the expected mission effectiveness and proposed cost of utilizing the proposed solution unmanned architectures. The most effective architectures included search, counter swarm, delivery, and attack systems.Lieutenant, United States NavyLieutenant, United States NavyLieutenant, United States NavyMajor, Republic of Singapore NavyMajor, Singapore ArmyLieutenant, United States NavyLieutenant, United States NavyLieutenant, United States NavyCommander, United States NavyApproved for public release. Distribution is unlimited
Communications Biophysics
COntains reports on six research projects.National Institutes of Health (Grant 2 P01 MH-04737-06)National Institutes of Health (Grant 5 ROl NB-05462-02)Joint Services Electronics Programs (U. S. Army, U. S. Navy, and U. S. Air Force) under Contract DA 36-039-AMC-03200(E)National Science Foundation (Grant GK-835)National Aeronautics and Space Administration (Grant NsG-496
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Results of the radiological and chemical characterization of surface impoundments 3539 and 3540 at Oak Ridge National Laboratory, Oak Ridge, Tennessee
A radiological and chemical characterization survey of impoundments 3539 and 3540 at the Oak Ridge National Laboratory (ORNL) was conducted during December 1997. Impoundments 3539 and 3540 are located in the Surface Impoundments Operable Unit (SIOU) of Waste Area Group 1. The investigation was performed by the Measurement Applications and Development Group of the Life Sciences Division of ORNL at the request of the Department of Energy (DOE) Office of Environmental Restoration. Sampling was conducted in order to quantify the presence of polychlorinated biphenyls (PCBs), Resource Conservation and Recovery Act (RCRA) constituents, and other contaminants of interest in support of the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA) remediation for the SIOU> The survey included collection of sediment/clay samples, quality control blank water samples and equipment rinsate samples for chemical and radiological analysis. Results show the samples contain traces of various organic, inorganic, and radioactive materials. Of particular interest are PCB values which demonstrate the impoundments are not regulated under the Toxic Substances Control Act
Gravitating Model Solitons
We study axially symmetric static solitons of O(3) nonlinear model
coupled to (2+1)-dimensional anti-de Sitter gravity. The obtained solutions are
not self-dual under static metric. The usual regular topological lump solution
cannot form a black hole even though the scale of symmetry breaking is
increased. There exist nontopological solitons of half integral winding in a
given model, and the corresponding spacetimes involve charged Baados-Teitelboim-Zanelli black holes without non-Abelian scalar hair.Comment: 35 pages, RevTe
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