1,360 research outputs found
Saline Conversion and Ice Structures from Artificially Grown Sea Ice
The environment of cold regions is generally viewed as inhospitable, primarily
due to application of ideal processes and techniques suitable to temperate
zones. The work herein is a step toward solving two environmental problems.
The first involves the supply of inexpensive, potable water in Arctic regions,
the lack of which is a severe detriment to development. Although water does
exist in the Arctic, it is neither available in potable form during many months
of the year nor does it occur in sufficient quantity near the point of use. Principally,
this lack is caused by the aridness of the Arctic and the shallowness
of fresh water sources which, for all practical purposes, do not exist but
freeze completely each winter season. The remaining liquid water source is
the sea. Arctic problems are then similar to other arid regions where the
conversion of sea water to potable water or the transmission of potable water
to desired locations is necessary. Cold temperatures generally preclude
transmission except over very short distances.
Desalination by freezing sea water is a much reported process and has been
included among the desalination processes under study worldwide. The
advantage of this method in the Arctic is the cold winter-time temperature
for freezing and the existence of adequate solar energy in the summer for
melting self purified ice. Power requirements are greatly reduced using these
natural phenomena.
The second aspect of this study concerns the use of artificially grown sea ice
as a structural material, thinking primarily in terms of coastal facilities such
as docks, jetties, islands, platforms, etc. At sufficiently high latitudes, the
summer ablation can be controlled to the point where major structures can be
maintained intact during the summer. The unit cost of material is quite low
because of low energy requirements.
The results of this study show that each of these sea water uses have considerable
promise. Desalination to potable level was accomplished. Ice growth
rates were obtained which indicate that ice structures of substantial size can
be built.This project was accomplished under a matching grant between the Office of
Water Resources Research, Department of the Interior, and the University
of Alaska, Arctic Environmental Engineering Laboratory. Funds available
under this grant purposefully did not anticipate the heavy logistic expense
in moving the project and equipment from Fairbanks to Kotzebue, Alaska.
Therefore, a major third contributor was the Alaska Air National Guard,
Kulis Air Force Base, Alaska. The support offered by the officers and men
of the Alaska Air National Guard was excellent and greatly appreciated
The Cost of Stability in Coalitional Games
A key question in cooperative game theory is that of coalitional stability,
usually captured by the notion of the \emph{core}--the set of outcomes such
that no subgroup of players has an incentive to deviate. However, some
coalitional games have empty cores, and any outcome in such a game is unstable.
In this paper, we investigate the possibility of stabilizing a coalitional
game by using external payments. We consider a scenario where an external
party, which is interested in having the players work together, offers a
supplemental payment to the grand coalition (or, more generally, a particular
coalition structure). This payment is conditional on players not deviating from
their coalition(s). The sum of this payment plus the actual gains of the
coalition(s) may then be divided among the agents so as to promote stability.
We define the \emph{cost of stability (CoS)} as the minimal external payment
that stabilizes the game.
We provide general bounds on the cost of stability in several classes of
games, and explore its algorithmic properties. To develop a better intuition
for the concepts we introduce, we provide a detailed algorithmic study of the
cost of stability in weighted voting games, a simple but expressive class of
games which can model decision-making in political bodies, and cooperation in
multiagent settings. Finally, we extend our model and results to games with
coalition structures.Comment: 20 pages; will be presented at SAGT'0
Application of tunable diode lasers as local oscillators in an Infrared Heterodyne Radiometer (IHR)
The utility of diode lasers as local oscillators (LOs) in a heterodyne receiver application was investigated. The CW power, spectral tunability, spectral stability, and spatial intensity distribution of the TDL outputs were measured. A tunable diode laser LO was incorporated into a laboratory Dicke-switched infrared heterodyne setup and used to measure radiometer sensitivity as well as spectroscopic characteristics of selected absorption lines of ammonia. The test results on one of the two tunable diode lasers are emphasized in an attempt to provide a comprehensive data package which may be useful for future planning purposes. The second tunable diode laser exhibits characteristics similar to the fully tested TDL with the exception that some changes in its performance characteristics as it was temperature cycled between room temperature and the operating temperature of approximately 50K occurred
Little Brown Bird
A personal essay reflecting on patient care and loss in medical school.
Berlin Prize 2020 First Place Winning Submissio
Optical constants of uranium plasma Final report
Thermodynamic and optical properties of uranium plasma in proposed gaseous core nuclear rocket
- …