scholarly journals Investigation of systematic bias in radiometric diameter determination of near-Earth asteroids: the night emission simulated thermal model (NESTM)

2009 ◽  
Vol 400 (1) ◽  
pp. 204-218 ◽  
Author(s):  
Stephen D. Wolters ◽  
Simon F. Green
Keyword(s):  
Thermal Model ◽  
Systematic Bias ◽  
Near Earth Asteroids

Determination of plasma bicarbonate of neonates in intensive care.

1988 ◽  
Vol 34 (7) ◽  
pp. 1483-1485 ◽  
Author(s):  
P Masters ◽  
M E Blackburn ◽  
M J Henderson ◽  
J F Barrett ◽  
P R Dear
Keyword(s):  
Intensive Care ◽  
Clinical Significance ◽  
Systematic Bias ◽  
Blood Gas ◽  
Laboratory Measurements ◽  
Blood Samples ◽  
Plasma Bicarbonate ◽  
A Value ◽  
Hasselbalch Equation

Abstract Most modern blood-gas analyzers are programmed to use the Henderson-Hasselbalch equation to calculate a value for plasma bicarbonate. It has been suggested, however, that among acutely ill patients, including newborns, these calculated values may be at variance with measured total CO2. To assess the clinical significance of such errors, we compared calculated bicarbonate with measured total CO2 in 79 blood samples from 40 babies in intensive care. The calculated bicarbonate values consistently exceeded the measured values by about 1.5 mmol/L. Of the errors, 94% were within the range -10% to +20%. When the systematic bias was removed, calculated and measured bicarbonate values agreed within +/- 3.30 mmol/L in 95% of cases. Because calculated values can be obtained much more quickly and frequently than laboratory measurements, we believe that these limits are clinically acceptable.

Preliminary Design of a Calorimeter for Experimental Determination of Effective Absorptivity of Metal Substrates During Laser Powder Deposition

2005 ◽  
Author(s):  
Jacob J. Koester ◽  
Michael A. Langerman ◽  
Umesh A. Korde ◽  
James W. Sears ◽  
Gregory A. Buck
Keyword(s):  
Experimental Data ◽  
Thermal Model ◽  
Laser Energy ◽  
Metal Substrate ◽  
Published Data ◽  
Preliminary Design ◽  
Laser Powder Deposition ◽  
Powder Deposition ◽  
Laser Energy Absorption

A thermal model of the laser powder deposition (LPD) process has been developed and tested. Results obtained from the model, however, are dependent upon the magnitude of the laser energy absorbed during the process. Although spectral absorptivities of metal surfaces are described in literature, during the LPD process, the powder increases the energy delivered to the substrate. There are no published data regarding this affect. Therefore, the SDSM&T Additive Manufacturing Laboratory (AML) is developing a calorimeter to experimentally investigate the affect of the powder on laser energy absorption at the metal substrate. The preliminary design is described in this paper with discussion on measures being taken to increase the accuracy of experimental data.

scholarly journals Physical models of asteroids from sparse photometric data

2006 ◽  
Vol 2 (S236) ◽  
pp. 191-200 ◽  
Author(s):  
Josef Ďurech ◽  
Petr Scheirich ◽  
Mikko Kaasalainen ◽  
Tommy Grav ◽  
Robert Jedicke ◽  
...  
Keyword(s):  
Photometric Data ◽  
Physical Models ◽  
Binary Asteroids ◽  
Rapid Response System ◽  
Response System ◽  
State Determination ◽  
Scientific Potential ◽  
Near Earth Asteroids ◽  
Realistic Shape

AbstractWe present an overview of our work on shape and spin state determination of asteroids from photometric data sparse in time. Our results are based on simulations that were performed using realistic shape and light-scattering models and time sequences that will be provided by Pan-STARRS (Panoramic Survey Telescope and Rapid Response System). We show some typical examples of physical model reconstruction of main belt and near-Earth asteroids and discuss the lightcurve inversion of slow and fast rotators, binary asteroids and tumbling asteroids. We emphasize the scientific potential of sparse photometric data to produce models of a large number of asteroids within the next few years.

scholarly journals Kharkiv study of near-Earth asteroids

2006 ◽  
Vol 2 (S236) ◽  
pp. 385-390 ◽  
Author(s):  
Yu. N. Krugly ◽  
N. M. Gaftonyuk ◽  
I. N. Belskaya ◽  
V. G. Chiorny ◽  
V. G. Shevchenko ◽  
...  
Keyword(s):  
Surface Properties ◽  
Crimean Astrophysical Observatory ◽  
Photometric System ◽  
Rotation Periods ◽  
Photometric Observations ◽  
National University ◽  
Ccd Observations ◽  
Asteroid Hazard ◽  
Near Earth Asteroids

AbstractThe regular CCD observations of near-Earth asteroids (NEAs) in the Institute of Astronomy of Kharkiv National University were initiated in 1995 within the framework of asteroid hazard problem in collaboration with the DLR, Institute of Planetary Research (Berlin). The main aim of the study is a determination of rotation periods and shapes of NEAs as well as astrometry of newly discovered objects. We also carry out the absolute photometry of NEAs in BVRI bands in order to put constraints on surface properties and to estimate their diameters. The observations are carried out with 0.7-m telescope of the Institute of Astronomy (Kharkiv) and with 1-m telescope of the Crimean Astrophysical Observatory (Simeiz) in the standard Johnson-Cousins photometric system. Some observations were made as an optical support of radar observation of NEAs. We present the results of photometric observations of 21 NEAs obtained in 2004-2006 which include asteroid rotation properties, diameters and shapes.

Traction Behavior of Some Lubricants Used for Rolling Bearings in Spacecraft Applications: Experiments and Thermal Model Based on Primary Laboratory Data

2001 ◽  
Vol 124 (1) ◽  
pp. 72-81 ◽  
Author(s):  
Daniel Ne´lias ◽  
Eric Legrand ◽  
Philippe Vergne ◽  
Jean-Bernard Mondier
Keyword(s):  
Thermal Model ◽  
Laboratory Data ◽  
Rolling Bearing ◽  
Operating Conditions ◽  
Model Parameters ◽  
Rolling Bearings ◽  
Traction Coefficient ◽  
Shear Heating ◽  
Rheological Experiments

Three synthetic oils used in spacecraft mechanisms (Pennzane SHF X2000, Nye 186 A, and Fomblin Z25) have been studied. Rheological tests were performed in order to characterize the behavior of each fluid versus pressure, temperature and shear rate. That includes the determination of the WLF viscosity model parameters. Tribological tests were carried out to measure the traction coefficient for operating conditions representative of spacecraft applications. Experimental results were compared with theoretical ones obtained using a non-newtonian thermal model. The modeling of traction in EHL contact is based on the Johnson and Tevaarwerk’s model modified to account for the shear heating of the fluid. The variations of the lubricant thermal conductivity with respect to temperature and pressure are also considered. In this model, input data comes directly from rheological experiments or are derived from other measurements through physical relationships. These rheological and tribological characterizations are essential to better describe the behavior of a lubricated rolling bearing.

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