Performance evaluation system for inertial navigation equipment

Testing system studies inertial characteristics of gyroscopic devices. System consisting of instrument support package, dynamic test table, torque control electronics, and real-time computer evaluates performance of prototype gyroscopic strapdown units in inertial-grade attitude-reference systems. System is applicable to commercial aircraft

Langley Research Center Metrology Program status for fiscal year 1987

The status of the Langley Research Center's metrology program for fiscal year 1987 is presented. The NASA Metrology Information System, which was operational for the entire year, provided the majority of performance data describing work analysis, turnaround time, out-of-tolerance instrument data, and other instrument service data. Calibration system development, equipment replacing and updating, status of last year's planned objectives, and Reference Standard certification requirements are described. The status of the LaRC voltage and resistance measurement assurance program and the agency-wide resistance program are reviewed. Progress on fiscal year 1987 objectives is discussed and fiscal year 1988 objectives are stated

Modelling cytoskeletal traffic: an interplay between passive diffusion and active transport

We introduce the totally asymmetric exclusion process with Langmuir kinetics (TASEP-LK) on a network as a microscopic model for active motor protein transport on the cytoskeleton, immersed in the diffusive cytoplasm. We discuss how the interplay between active transport along a network and infinite diffusion in a bulk reservoir leads to a heterogeneous matter distribution on various scales. We find three regimes for steady state transport, corresponding to the scale of the network, of individual segments or local to sites. At low exchange rates strong density heterogeneities develop between different segments in the network. In this regime one has to consider the topological complexity of the whole network to describe transport. In contrast, at moderate exchange rates the transport through the network decouples, and the physics is determined by single segments and the local topology. At last, for very high exchange rates the homogeneous Langmuir process dominates the stationary state. We introduce effective rate diagrams for the network to identify these different regimes. Based on this method we develop an intuitive but generic picture of how the stationary state of excluded volume processes on complex networks can be understood in terms of the single-segment phase diagram.Comment: 5 pages, 7 figure

Introduction to total- and partial-pressure measurements in vacuum systems

An introduction to the fundamentals of total and partial pressure measurement in the vacuum regime (760 x 10 to the -16th power Torr) is presented. The instrument most often used in scientific fields requiring vacuum measurement are discussed with special emphasis on ionization type gauges and quadrupole mass spectrometers. Some attention is also given to potential errors in measurement as well as calibration techniques

The midwife factor in obstetric procedures and neonatal outcome

Aims. In the face of major tendency towards midwiferyled-care it was our purpose to investigate the extent of the influence of the midwife on the rates of obstetric procedures and perinatal outcome. Methods. 5384 consecutive deliveries at the Department of Obstetrics and Gynecology. University of Graz, were enrolled in the study. The following data were collected: mode of delivery, pH of umbilical artery, Apgar score. Firstly, data were investigated for interindividual differences and, secondly, for relationship with age of the midwife as a measure of experience. Results. Interindividual differences were significant for episiotomy rates (minimum: 31.6%; maximum 76.9%; p<0.001), forceps rates (minimum: 1.7%; maximum 11.1%;p=0.002) and pH of umbilical arteries (minimum: 7.21:maxinium: 7.28 p=0.001) but not for cesarean section rates and Apgar scores. Linear regression analysis was significant between age of midwives and pH of umbilical arteries (p<0.001: r=0.055) and for one-minute Apgar score (p=0.009; r=0.050) but not for episiotomy rates, cesarean section rates, forceps rates and five-minutes Apgar score. Conclusions. There are large interindividual differences in obstetric intervention rates which cannot be explained by the midwives' age. Provision of health care should be primarily determined by need and not by the personal characteristics of the health care provider, thus interindividual differences should be reduced and more often taken into account when analyzing any kind of data

Photochemical Reductive trans-Elimination from trans-Diacidotetracyanoplatinate(IV) Complexes

Abstract Upon CT excitation the complex ions trans-[Pt(CN)4N3X]2- and trans-[Pt(CN)4X2]2- (X = Cl and Br) undergo a reductive trans-elimination with formation of [Pt(CN)4]2- and two ligand radicals in the photoprimary step. The formation of a Pt(III) intermediate is not observed. Due to the stability of [Pt(CN)4]2-, recombination reactions regenerating the starting complex are efficient if the ligand radicals are not scavenged. For the azide complexes the high quantum yields for the production of [Pt(CN)4]2- are explained by the instability of azide radicals. For trans-[Pt(CN)4X2]2-, the recombination is efficient in aqueous solution, while in ethanol the halogen atoms are scavenged by hydrogen abstraction. The sequence of steps following CT excitation can be explained by a potential energy diagram.</jats:p

Phase closure nulling of HD 59717 with AMBER/VLTI . Detection of the close faint companion

Aims: The detection of close and faint companions is an essential step in many astrophysical fields, including the search for planetary companions. A new method called "phase closure nulling" has been proposed for the detection of such faint and close companions based on interferometric observations when the system visibility amplitude is close to zero due to the large diameter of the primary star. We aim at demonstrating this method by analyzing observations obtained on the spectroscopic binary HD 59717. Methods: Using the AMBER/VLTI instrument in the K-band with ~1500 spectral resolution, we record the spectrally dispersed closures phases of the SB1 binary HD 59717 with a three-baseline combination adequate for applying phase closure methods. After a careful data reduction, we fit the primary diameter, the binary flux ratio, and the separation using the phase closure data. Results: We detect the 5-mag fainter companion of HD 59717 at a distance of 4 stellar radii from the primary. We determine the diameter of the primary, infer the secondary's spectral type and determine the masses and sizes of the stars in the binary system. This is one of the highest contrasts detected by interferometry between a companion and its parent star. Based on observations collected at the European Southern Observatory, Paranal, Chile, within the commissioning programme 60.A-9054(A)