Ablation model validation and analytical sensitivity study for the Mars Pathfinder heat shield

Author(s):  
William Congdon
2015 ◽  
Vol 96-97 ◽  
pp. 903-906 ◽  
Author(s):  
Anatoly Panin ◽  
Mikhail Khovayko ◽  
Yury Krasikov ◽  
Alexander Nemov ◽  
Wolfgang Biel ◽  
...  

2013 ◽  
Vol 50 (6) ◽  
pp. 1171-1182 ◽  
Author(s):  
Milad Mahzari ◽  
Robert D. Braun ◽  
Todd R. White

Author(s):  
R. Levi-Setti ◽  
J. M. Chabala ◽  
R. Espinosa ◽  
M. M. Le Beau

We have shown previously that isotope-labelled nucleotides in human metaphase chromosomes can be detected and mapped by imaging secondary ion mass spectrometry (SIMS), using the University of Chicago high resolution scanning ion microprobe (UC SIM). These early studies, conducted with BrdU- and 14C-thymidine-labelled chromosomes via detection of the Br and 28CN- (14C14N-> labelcarrying signals, provided some evidence for the condensation of the label into banding patterns along the chromatids (SIMS bands) reminiscent of the well known Q- and G-bands obtained by conventional staining methods for optical microscopy. The potential of this technique has been greatly enhanced by the recent upgrade of the UC SIM, now coupled to a high performance magnetic sector mass spectrometer in lieu of the previous RF quadrupole mass filter. The high transmission of the new spectrometer improves the SIMS analytical sensitivity of the microprobe better than a hundredfold, overcoming most of the previous imaging limitations resulting from low count statistics.


Author(s):  
J. Zhang ◽  
D.B. Williams ◽  
J.I. Goldstein

Analytical sensitivity and spatial resolution are important and closely related factors in x-ray microanalysis using the AEM. Analytical sensitivity is the ability to distinguish, for a given element under given conditions, between two concentrations that are nearly equal. The analytical sensitivity is directly related to the number of x-ray counts collected and, therefore, to the probe current, specimen thickness and counting time. The spatial resolution in AEM analysis is determined by the probe size and beam broadening in the specimen. A finer probe and a thinner specimen give a higher spatial resolution. However, the resulting lower beam current and smaller X-ray excitation volume degrade analytical sensitivity. A compromise must be made between high spatial resolution and an acceptable analytical sensitivity. In this paper, we show the necessity of evaluating these two parameters in order to determine the low temperature Fe-Ni phase diagram.A Phillips EM400T AEM with an EDAX/TN2000 EDS/MCA system and a VG HB501 FEG STEM with a LINK AN10 EDS/MCA system were used.


1964 ◽  
Vol 7 (4) ◽  
pp. 389-393 ◽  
Author(s):  
David C. Shepherd ◽  
Robert Goldstein ◽  
Benjamin Rosenblüt

Two separate studies investigated race and sex differences in normal auditory sensitivity. Study I measured thresholds at 500, 1000, and 2000 cps of 23 white men, 26 white women, 21 negro men, and 24 negro women using the method of limits. In Study II thresholds of 10 white men, 10 white women, 10 negro men, and 10 negro women were measured at 1000 cps using four different stimulus conditions and the method of adjustment by means of Bekesy audiometry. Results indicated that the white men and women in Study I heard significantly better than their negro counterparts at 1000 and 2000 cps. There were no significant differences between the average thresholds measured at 1000 cps of the white and negro men in Study II. White women produced better auditory thresholds with three stimulus conditions and significantly more sensitive thresholds with the slow pulsed stimulus than did the negro women in Study II.


2017 ◽  
Vol 04 (03) ◽  
pp. 231-236 ◽  
Author(s):  
Barham S. Mahmood ◽  
Jagar Ali ◽  
Shirzad B. Nazhat ◽  
David Devlin

AIAA Journal ◽  
2001 ◽  
Vol 39 ◽  
pp. 308-314
Author(s):  
G. Greschik ◽  
M. Mikulas ◽  
A. Palisoc ◽  
C. Cassapakis ◽  
G. Veal
Keyword(s):  

Sign in / Sign up

Export Citation Format

Share Document