A Martian Quarantine Risk Model
Structured model using loss functions to assess risk of using given decontamination procedure on all Martian unmanned landing craft
Cornell, R. G.↗
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Results for “structure function”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Mass spectrometry in structural and stereochemical problems. CXXXVII - Examples of interaction of remote functional groups after electron impact.
Cyclic ketones containing methoxyl and hydroxyl studied for oxygen rearrangement on electron impact
Djerassi, C.↗
Skylab status report
Skylab experiments, spacecraft facilities and project status, discussing operations, crew functions and weight of structure, systems, consumables and related storage
Schneider, W. C.↗
Origin and development of plasma membrane derived invaginations in Vinca rosea l.
The occurrence, morphology, and possible ontogeny of plasma-membrane-related structures are described which can develop into invaginations or intravacuolar formations. An underlying study of meristematic tissues from the shoot of Vinca rosea supports the interpretation that endocytosis does occur in plant cells and that it is appropriate to refer to these structures as endocytoses. The function of these invaginations or their content remains to be elucidated.
Mahlberg, P.↗
The ergodic decomposition of stationary discrete random processes
The ergodic decomposition is discussed, and a version focusing on the structure of individual sample functions of stationary processes is proved for the special case of discrete-time random processes with discrete alphabets. The result is stronger in this case than the usual theorem, and the proof is both intuitive and simple. Estimation-theoretic and information-theoretic interpretations are developed and applied to prove existence theorems for universal source codes, both noiseless and with a fidelity criterion.
Gray, R. M.↗
Two dimensional turbulence in inviscid fluids or guiding center plasmas
Analytic theory for two-dimensional turbulent equilibria for the inviscid Navier-Stokes equations is examined mathematically. Application of the technique to electrostatic guiding center plasma is discussed. A good fit is demonstrated for the approach to a predicted energy per Fourier mode obtained from a two-temperature canonical ensemble. Negative as well as positive temperature regimes are explored. Fluctuations about the mean energy per mode also compare well with theory. In the regime of alpha less than zero, beta greater than zero, with the minimum value of alpha plus beta times k squared near zero, contour plots of the stream function reveal macroscopic vortex structures similar to those seen previously in discrete vortex simulations. Eulerian direct interaction equations, which can be used to follow the approach to inviscid equilibrium, are derived.
Seyler, C. E., Jr.↗
Cases in the relation of research on remote sensing to decisionmakers in a state agency
The use is considered of various management tools in order to assess their effects on the anticipated relevance of the remote sensing research to the needs of government agencies. Among these tools are different organizational structures and ways of functioning, which are applied to the design and management of projects and to the communication of research results. The characteristics of data and information flow, and technology transfer are discussed along with the management of three projects and a remote sensing data center in terms of the use of some tools for influencing these processes.
Jondrow, J. W.↗
Digital filter structures having low errors and simple hardware implementation
Sensitivity and roundoff errors can seriously limit the application of recursive digital filters in practice, particularly when the filters have poles near z = + 1. A filter structure, based on digital incremental computers is proposed, which has low sensitivity, good error characteristics, and simple hardware implementation for pole locations close to z = + 1. Expressions for the roundoff errors are derived and compared to those for conventional structures. A design procedure is suggested to implement the new filter structure given the transfer function. Simulation results are presented.
Abu-El-haija, A. I.↗
The IFIP WG 2.5 proposals on FORTRAN
Language problem areas are summarized and possible solutions are discussed. Areas covered are: (1) double complex, (2) arrays of work space in library subroutines, (3) calls from a library subprogram to user code, (4) decomposition and synthesis of floating-point numbers, (5) environment parameters, (6) precision function, and (7) control structures.
Lawson, C. L.↗
Preliminary trend monitoring system data manager's guide
The functions and data base structures that the data base manager will be responsible for maintaining are documented. All normal and error sequences are included.
Turberville, L.↗
A structure suitable for implementing digital filters with poles near z = +1
Errors limiting the application of recursive digital filters which have poles near z = +1 are considered, and a filter structure for pole locations close to z = +1 is proposed. The filter structure, based on digital incremental computers, has low sensitivity and good error characteristics for pole locations near z = +1. Expressions for the roundoff error are derived, and errors associated with the proposed structure and a conventional structure are compared. A design procedure is suggested for implementing the new filter structure when the transfer function is given. Simulation results are presented.
Abu-El-haija, A. I.↗
H Lyman-alpha emission from photodissociation of H2O
Lyman-alpha fluorescence measurements were used to study the photodissociation of water vapor to produce H(n equals 2) atoms from threshold to 500 A. The experimental threshold of 813.0 A nearly coincides with the thermodynamic limit. Excitation cross sections rise slowly from threshold to a maximum value of (1.55 plus or minus 0.12) x 10 to the -18th sq cm at about 709 A and decrease to a negligible value below 550 A. Structure in the excitation function is attributed to predissociation of Rydberg series converging to the B(overbar)B2 state of H2O(plus).
Mentall, J. E.↗
Escape of heated ions upstream of quasi-parallel shocks
A simple theoretical criterion by which quasi-parallel and quasi-perpendicular collisionless shocks may be distinguished is proposed on the basis of an investigation of the free escape of ions from the post-shock plasma into the region upstream of a fast collisionless shock. It was determined that the accessibility of downstream ions to the upstream region depends on upstream magnetic field shock normal angle, in addition to the upstream plasma parameters, with post-shock ions escaping upstream for shock normal angles of less than 45 deg, in agreement with the observed transition between quasi-parallel and quasi-perpendicular shock structure. Upstream ion distribution functions resembling those of observed intermediate ions and beams are also calculated.
Edmiston, J. P.↗
Structural optimization - Challenges and opportunities
A review of developments in structural optimization techniques and their interface with growing computer capabilities is presented. Structural design steps comprise functional definition of an object, an evaluation phase wherein external influences are quantified, selection of the design concept, material, object geometry, and the internal layout, and quantification of the physical characteristics. Optimization of a fully stressed design is facilitated by use of nonlinear mathematical programming which permits automated definition of the physics of a problem. Design iterations terminate when convergence is acquired between mathematical and physical criteria. A constrained minimum algorithm has been formulated using an Augmented Lagrangian approach and a generalized reduced gradient to obtain fast convergence. Various approximation techniques are mentioned. The synergistic application of all the methods surveyed requires multidisciplinary teamwork during a design effort.
Sobieszczanski-Sobieski, J.↗
Structural optimization: Challenges and opportunities
A review of developments in structural optimization techniques and their interface with growing computer capabilities is presented. Structural design steps comprise functional definition of an object, an evaluation phase wherein external influences are quantified, selection of the design concept, material, object geometry, and the internal layout, and quantification of the physical characteristics. Optimization of a fully stressed design is facilitated by use of nonlinear mathematical programming which permits automated definition of the physics of a problem. Design iterations terminate when convergence is acquired between mathematical and physical criteria. A constrained minimum algorithm has been formulated using an Augmented Lagrangian approach and a generalized reduced gradient to obtain fast convergence. Various approximation techniques are mentioned. The synergistic application of all the methods surveyed requires multidisciplinary teamwork during a design effort.
Sobieszczanski-Sobieski, J.↗
Far-infrared laser magnetic resonance of vibrationally excited CD2
The detection of 13 rotational transitions in the first excited bending state (010) of CD2 using the technique of far-infrared laser magnetic resonance spectroscopy is reported. Molecular parameters for this state are determined from these new data together with existing infrared observations of the v(2) band. Additional information on the ground vibrational state (000) is also provided by the observation of a new rotational transition, and this is combined with existing data to provide a refined set of molecular parameters for the CD2 ground state. One spectrum has been observed that is assigned as a rotational transition within the first excited symmetric stretching state (100) of CD2. These data will be of use in refining the structure and the potential function of the methylene radical.
Evenson, K. M.↗
Experimental methods for quenching structures in lunar-analog silicate melts: Variations as a function of quench media and composition
Compositions analogous to lunar green, organge, and brown glasses were synthesized under consistent conditions, then quenched into a variety of different media when the samples were removed from the furnace. Iron valence and coordination are a direct function of quench media used, spanning the range from brine/ice (most effective quench), water, butyl phthalate, silicone oil, liquid nitrogen, highly reducing CO-CO2 gas, to air (least efficient quench). In the green and brown glasses, Fe(3+) in four-fold and six-fold coordination is observed in the slowest-quenched samples; Fe(2+) coordination varies directly with quench efficiency. Less pronounced changes were observed in the Ti-rich orange glass. Therefore the remote-sensed spectrum of a glass-bearing regolith on the Moon may be influenced by the process by which the glass cooled, and extreme caution must be used when comparing spectra of synthetic glass analogs with real lunar glasses.
Dyar, M. D.↗
Experimental methods for quenching structures in lunar-analog silicate melts - Variations as a function of quench media and composition
Compositions analogous to lunar green, orange, and brown glasses were synthesized under consistent conditions, then quenched into a variety of different media when the samples were removed from the furnace. Iron valence and coordination are a direct function of quench media used, spanning the range from brine/ice (most effective quench), water, butyl phthalate, silicone oil, liquid nitrogen, highly reducing CO-CO2 gas, to air (least efficient quench). In the green and brown glasses, Fe(3+) in four-fold and six-fold coordination is observed in the slowest-quenched samples; Fe(2+) coordination varies directly with quench efficiency. Less pronounced changes were observed in the Ti-rich orange glass. Therefore the remote-sensed spectrum of a glass-bearing regolith on the moon may be influenced by the process by which the glass cooled, and extreme caution must be used when comparing spectra of synthetic glass analogs with real lunar glasses.
Dyar, M. D.↗