7,623 research outputs found
Implications of non-feasible transformations among icosahedral orbitals
The symmetric group that permutes the six five-fold axes of an
icosahedron is introduced to go beyond the simple rotations that constitute the
icosahedral group . Owing to the correspondence , the
calculation of the Coulomb energies for the icosahedral configurations
based on the sequence can be brought
to bear on Racah's classic theory for the atomic d shell based on . Among the elements of is the kaleidoscope
operator that rotates the weight space of SO(5) by . Its use
explains some puzzling degeneracies in d^3 involving the spectroscopic terms
^2P, ^2F, ^2G and ^2H.Comment: Tentatively scheduled to appear in Physical Preview Letters Apr 5,
99. Revtex, 1 ps figur
Development of an integrated low-power RF partial discharge detector
This paper presents the results from integrating a low-power partial discharge detector with a wireless sensor node designed for operating as part of an IEEE 802.15.4 sensor network, and applying an on-line classifier capable of classifying partial discharges in real-time. Such a system is of benefit to monitoring engineers as it provides a means to exploit the RF technique using a low-cost device while circumventing the need for any additional cabling associated with new condition monitoring systems. The detector uses a frequency-based technique to differentiate between multiple defects, and has been integrated with a SunSPOT wireless sensor node hosting an agent-based monitoring platform, which includes a data capture agent and rule induction agent trained using experimental data. The results of laboratory system verification are discussed, and the requirements for a fully robust and flexible system are outlined
A pilot level decision analysis of thermionic reactor development strategy for nuclear electric propulsion
The development policy for thermionic reactors to provide electric propulsion and power for space exploration was analyzed to develop a logical procedure for selecting development alternatives that reflect the technical feasibility, JPL/NASA project objectives, and the economic environment of the project. The partial evolution of a decision model from the underlying philosophy of decision analysis to a deterministic pilot phase is presented, and the general manner in which this decision model can be employed to examine propulsion development alternatives is illustrated
More on coupling coefficients for the most degenerate representations of SO(n)
We present explicit closed-form expressions for the general group-theoretical
factor appearing in the alpha-topology of a high-temperature expansion of
SO(n)-symmetric lattice models. This object, which is closely related to
6j-symbols for the most degenerate representation of SO(n), is discussed in
detail.Comment: 9 pages including 1 table, uses IOP macros Update of Introduction and
Discussion, References adde
(SNP074) Loula Judd, interviewed by Nancy Smith
Records the reminiscences of Loula Judd, who lived near the Big Meadows area of Shenandoah National Park until the mid 1930s. Describes daily life in the mountains, including local agriculture, livestock and food preservation, as well as important cash crops. Recalls the traditional remedies used for common ailments and injuries, as well as a brief discussion on the Influenza Epidemic of 1918. Includes comments on local entrepreneur, George Pollock, owner of Skyland resort and the construction of Camp Hoover, the presidential retreat created by Herbert Hoover.https://commons.lib.jmu.edu/snp/1064/thumbnail.jp
Inheritance of Awns in a Cross Between Hard Federation and Kota Wheats
During the past few years there have been numerous studies made of various characters in wheat. Some characters which were thought at first to be simple in inheritance have since been found to be rather complex.
The data in the following pages are the results of an investigation made to study the inheritance of awns in a cross between Hard Federation and Kota varieties of wheat.
Until the last few years awn inheritance in wheat has been regarded as extremely simple, that is, as being dependent on a single factor difference. The awns of the F1 plants have nearly always been intermediate in length between the awns of the two parents with the F2 ratios 3:1 or 1:2:1, awnlessness usually being regarded as dominant. Recently, however, it has become apparent that the inheritance of awns is much more complex than the original data indicated. Several workers have found two independent factors and one has found two factors segregating in such a fashion as strongly to suggest linkage between these two factors
(SNP075) Loula Judd, interviewed by Nancy Smith
Continues an earlier interview, (SdArch no. SNP-74), with Loula Judd, who lived near the Big Meadows area of Shenandoah National Park until the mid 1930s. Describes the wildlife found in the mountains, including venomous snakes, wolves and other predators. Discusses the slave trade in the region before the Civil War and includes anecdotes about Herbert Hoover, whom the local people often encountered during his frequent stays at the nearby presidential retreat, Camp Hoover.https://commons.lib.jmu.edu/snp/1065/thumbnail.jp
New methodology for assessing the probability of contaminating Mars
Methodology is proposed to assess the probability that the planet Mars will be contaminated by terrestrial microorganisms aboard a spacecraft. The present NASA methods are extended to permit utilization of detailed information on microbial characteristics, the lethality of release and transport mechanisms, and of other information about the Martian environment. Different types of microbial release are distinguished, and for each release mechanism a probability of growth is computed. Using this new methodology, an assessment was carried out for the 1975 Viking landings on Mars. The resulting probability of contamination for each Viking lander is 6 x 10 to the -6 power, and is amenable to revision as additional information becomes available
Assessment of the probability of contaminating Mars
New methodology is proposed to assess the probability that the planet Mars will by biologically contaminated by terrestrial microorganisms aboard a spacecraft. Present NASA methods are based on the Sagan-Coleman formula, which states that the probability of contamination is the product of the expected microbial release and a probability of growth. The proposed new methodology extends the Sagan-Coleman approach to permit utilization of detailed information on microbial characteristics, the lethality of release and transport mechanisms, and of other information about the Martian environment. Three different types of microbial release are distinguished in the model for assessing the probability of contamination. The number of viable microbes released by each mechanism depends on the bio-burden in various locations on the spacecraft and on whether the spacecraft landing is accomplished according to plan. For each of the three release mechanisms a probability of growth is computed, using a model for transport into an environment suited to microbial growth
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