32,598 research outputs found
Claim your space: re-placing spaces to better meet the needs of the net generation
The challenge for the Reid Library at The University of Western Australia was the transformation of a 1960s building into a welcoming space with services and facilities appropriate for a more technologically demanding generation. A key issue was how to balance the continuing need for access to physical collections with the rapidly expanding demand for new kinds of learning spaces and facilities oriented towards on-line and collaborative learning and research. This paper outlines the approach taken to identify client needs (both physical and virtual), define and propose new service models, and transform learning spaces while maintaining access to physical collections
Workshop on the Early Earth: The Interval from Accretion to the Older Archean
Presentation abstracts are compiled which address various issues in Earth developmental processes in the first one hundred million years. The session topics included: accretion of the Earth (processes accompanying immediately following the accretion, including core formation); impact records and other information from planets and the Moon relevant to early Earth history; isotopic patterns of the oldest rocks; and igneous, sedimentary, and metamorphic petrology of the oldest rocks
System diagnostic builder
The System Diagnostic Builder (SDB) is an automated software verification and validation tool using state-of-the-art Artificial Intelligence (AI) technologies. The SDB is used extensively by project BURKE at NASA-JSC as one component of a software re-engineering toolkit. The SDB is applicable to any government or commercial organization which performs verification and validation tasks. The SDB has an X-window interface, which allows the user to 'train' a set of rules for use in a rule-based evaluator. The interface has a window that allows the user to plot up to five data parameters (attributes) at a time. Using these plots and a mouse, the user can identify and classify a particular behavior of the subject software. Once the user has identified the general behavior patterns of the software, he can train a set of rules to represent his knowledge of that behavior. The training process builds rules and fuzzy sets to use in the evaluator. The fuzzy sets classify those data points not clearly identified as a particular classification. Once an initial set of rules is trained, each additional data set given to the SDB will be used by a machine learning mechanism to refine the rules and fuzzy sets. This is a passive process and, therefore, it does not require any additional operator time. The evaluation component of the SDB can be used to validate a single software system using some number of different data sets, such as a simulator. Moreover, it can be used to validate software systems which have been re-engineered from one language and design methodology to a totally new implementation
Absorption and Screening in Phycomyces
In vivo absorption measurements were made through the photosensitive zones of Phycomyces sporangiophores and absorption spectra are presented for various growth media and for wavelengths between 400 and 580 mµ. As in mycelia, ß-carotene was the major pigment ordinarily found. The addition of diphenylamine to the growth media caused a decrease in ß-carotene and an increase in certain other carotenoids. Growth in the dark substantially reduced the amount of ß-carotene in the photosensitive zone; however, growth on a lactate medium failed to suppress ß-carotene in the growing zone although the mycelia appeared almost colorless. Also when diphenylamine was added to the medium the absorption in the growing zone at 460 mµ was not diminished although the colored carotenoids in the bulk of the sporangiophore were drastically reduced. Absorption which is characteristic of the action spectra was not found. Sporangiophores immersed in fluids with a critical refractive index show neither positive nor negative tropism. Measurements were made of the critical refractive indices for light at 495 and 510 mµ. The critical indices differed only slightly. Assuming primary photoreceptors at the cell wall, the change in screening due to absorption appears too large to be counterbalanced solely by a simple effect of the focusing change. The possibility is therefore advanced that the receptors are internal to most of the cytoplasm; i.e., near the vacuole
A combined R-matrix eigenstate basis set and finite-differences propagation method for the time-dependent Schr\"{od}dinger equation: the one-electron case
In this work we present the theoretical framework for the solution of the
time-dependent Schr\"{o}dinger equation (TDSE) of atomic and molecular systems
under strong electromagnetic fields with the configuration space of the
electron's coordinates separated over two regions, that is regions and
. In region the solution of the TDSE is obtained by an R-matrix basis
set representation of the time-dependent wavefunction. In region a grid
representation of the wavefunction is considered and propagation in space and
time is obtained through the finite-differences method. It appears this is the
first time a combination of basis set and grid methods has been put forward for
tackling multi-region time-dependent problems. In both regions, a high-order
explicit scheme is employed for the time propagation. While, in a purely
hydrogenic system no approximation is involved due to this separation, in
multi-electron systems the validity and the usefulness of the present method
relies on the basic assumption of R-matrix theory, namely that beyond a certain
distance (encompassing region ) a single ejected electron is distinguishable
from the other electrons of the multi-electron system and evolves there (region
II) effectively as a one-electron system. The method is developed in detail for
single active electron systems and applied to the exemplar case of the hydrogen
atom in an intense laser field.Comment: 13 pages, 6 figures, submitte
Power and Propulsion Element (PPE) Spacecraft Reference Trajectory Document
This document captures example reference trajectories for the PPE including a reference delivery orbit and orbit maintenance, an example cislunar orbit transfer and end-of-mission (EOM) disposal trajectory. The flexibility of electric propulsion offers, by its low thrust nature, multiple different trajectory options to transfer from one orbit to another. The trajectories captured in this document are representative examples of a low thrust transfer from the NRHO and to multiple cislunar orbits. This document provides a consistent set of data from mission design to be used in the design of the vehicle capable of flying the trajectory described. The data in this document will be used to create conference papers. In order to do so, we are ending this document through for external release
Some consequences of intense electromagnetic wave injection into space plasmas
The future possibility of actively testing the current understanding of how energetic particles may be accelerated in space or dumped from the radiation belts using intense electromagnetic energy from ground based antennas is discussed. The ground source of radiation is merely a convenience. A space station source for radiation that does not have to pass through the atmosphere and lower ionosphere, is an attractive alternative. The text is divided into two main sections addressing the possibilities of: (1) accelerating electrons to fill selected flux tubes above the Kennel-Petscheck limit for stably trapped fluxes, and (2) using an Alfven maser to cause rapid depletion of energetic protons or electrons from the radiation belts
High Voltage CMOS Control Interface for Astronomy - Grade Charged Coupled Devices
The Pan-STARRS telescope consists of an array of smaller mirrors viewed by a
Gigapixel arrays of CCDs. These focal planes employ Orthogonal Transfer CCDs
(OTCCDs) to allow on-chip image stabilization. Each OTCCD has advanced logic
features that are controlled externally. A CMOS Interface Device for High
Voltage has been developed to provide the appropiate voltage signal levels from
a readout and control system designated STARGRASP. OTCCD chip output levels
range from -3.3V to 16.7V, with two different output drive strenghts required
depending on load capacitance (50pF and 1000pF), with 24mA of drive and a rise
time on the order of 100ns. Additional testing ADC structures have been
included in this chip to evaluate future functional additions for a next
version of the chip.Comment: 13 pages, 17 gigure
Star Formation History since z = 1.5 as Inferred from Rest-Frame Ultaviolet Luminosity Density Evolution
We investigate the evolution of the universal rest-frame ultraviolet
luminosity density from z = 1.5 to the present. We analyze an extensive sample
of multicolor data (U', B, V = 24.5) plus spectroscopic redshifts from the
Hawaii Survey Fields and the Hubble Deep Field. Our multicolor data allow us to
select our sample in the rest-frame ultraviolet (2500 angstrom) over the entire
redshift range to z = 1.5. We conclude that the evolution in the luminosity
density is a function of the form (1+z)^{1.7\pm1.0} for a flat lambda cosmology
and (1+z)^{2.4\pm1.0} for an Einstein-de Sitter cosmology.Comment: 12 pages, 7 figs, 5 tables, submitted to A
- …