The Variable Frame Theory of Focal Points: An Experimental Study

1997 ◽  
Vol 19 (1) ◽  
pp. 1-45 ◽  
Author(s):  
Michael Bacharach ◽  
Michele Bernasconi
Keyword(s):  
Experimental Study ◽  
Frame Theory ◽  
Focal Points

scholarly journals Factors Contributing to Increased Blast Overpressure Inside Modern Ballistic Helmets

2020 ◽  
Vol 10 (20) ◽  
pp. 7193
Author(s):  
Maciej Skotak ◽  
Jonathan Salib ◽  
Anthony Misistia ◽  
Arturo Cardenas ◽  
Eren Alay ◽  
...  
Keyword(s):  
Experimental Study ◽  
Shock Tube ◽  
Principle Component Analysis ◽  
Hot Spots ◽  
Shape Factor ◽  
Elevated Pressure ◽  
Focal Points ◽  
Parietal Region ◽  
Blast Overpressure ◽  
Pressure Fields

This study demonstrates the orientation and the "shape factor" have pronounced effects on the development of the localized pressure fields inside of the helmet. We used anatomically accurate headform to evaluate four modern combat helmets under blast loading conditions in the shock tube. The Advanced Combat Helmet (ACH) is used to capture the effect of the orientation on pressure under the helmet. The three modern combat helmets: Enhanced Combat Helmet (ECH), Ops-Core, and Airframe, were tested in frontal orientation to determine the effect of helmet geometry. Using the unhelmeted headform data as a reference, we characterized pressure distribution inside each helmet and identified pressure focal points. The nature of these localized “hot spots” is different than the elevated pressure in the parietal region of the headform under the helmet widely recognized as the under-wash effect also observed in our tests. It is the first experimental study which indicates that the helmet presence increased the pressure experienced by the eyes and the forehead (glabella). Pressure fingerprinting using an array of sensors combined with the application of principle component analysis (PCA) helped elucidate the subtle differences between helmets.

scholarly journals Factors Contributing to Increased Blast Overpressure inside Modern Ballistic Helmets

2020 ◽  
Author(s):  
Maciej Skotak ◽  
Jonathan Salib ◽  
Anthony Misistia ◽  
Arturo Cardenas ◽  
Eren Alay ◽  
...  
Keyword(s):  
Experimental Study ◽  
Principle Component Analysis ◽  
Hot Spots ◽  
Shape Factor ◽  
Pressure Sensors ◽  
Elevated Pressure ◽  
Focal Points ◽  
Parietal Region ◽  
Blast Overpressure ◽  
Pressure Fields

This study demonstrates the orientation and the ‘shape factor’ have pronounced effects on the development of the localized pressure fields inside of the helmet. We used anatomically accurate headform to evaluate four modern combat helmets under blast loading conditions in the shock tube. The Advanced Combat Helmet (ACH) is used to capture the effect of the orientation on pressure under the helmet. The three modern combat helmets: ECH, Ops-Core, and Airframe, were tested in frontal orientation to determine the effect of helmet geometry. Using the unhelmeted headform data as a reference, we characterized pressure distribution inside each helmet and identified pressure focal points. The nature of these localized “hot spots” is different than the elevated pressure in the parietal region of the headform under the helmet widely recognized as the under-wash effect also observed in our tests. It is the first experimental study which indicates that the helmet presence increased the pressure experienced by the eyes (as evidenced by the pressure sensors in the H8 and H9 locations), and the forehead (denoted as H1 location). Pressure fingerprinting using an array of sensors combined with the application of principle component analysis (PCA) helped elucidate the subtle differences between helmets.

Experimental Study to Produce Multiple Focal Points of Acoustic Field for Active Path Selection of Microbubbles through Multi-bifurcation

2013 ◽  
Vol 52 (7S) ◽  
pp. 07HF13 ◽  
Author(s):  
Ren Koda ◽  
Jun Koido ◽  
Takumi Ito ◽  
Takashi Mochizuki ◽  
Kohji Masuda ◽  
...  
Keyword(s):  
Experimental Study ◽  
Acoustic Field ◽  
Path Selection ◽  
Focal Points ◽  
Active Path ◽  
Selection Of

Experimental study on the restoration from a tilt-azimuth series for improvement in resolution

1995 ◽  
Vol 53 ◽  
pp. 636-637
Author(s):  
Norio Baba ◽  
Norihiko Ichise ◽  
Syunya Watanabe
Keyword(s):  
Experimental Study ◽  
Spherical Aberration ◽  
Incident Beam ◽  
Optical Parameters ◽  
Beam Tilting ◽  
Illumination Method ◽  
Restoration Method ◽  
Illumination Mode

The tilted beam illumination method is used to improve the resolution comparing with the axial illumination mode. Using this advantage, a restoration method of several tilted beam images covering the full azimuthal range was proposed by Saxton, and experimentally examined. To make this technique more reliable it seems that some practical problems still remain. In this report the restoration was attempted and the problems were considered. In our study, four problems were pointed out for the experiment of the restoration. (1) Accurate beam tilt adjustment to fit the incident beam to the coma-free axis for the symmetrical beam tilting over the full azimuthal range. (2) Accurate measurements of the optical parameters which are necessary to design the restoration filter. Even if the spherical aberration coefficient Cs is known with accuracy and the axial astigmatism is sufficiently compensated, at least the defocus value must be measured. (3) Accurate alignment of the tilt-azimuth series images.

An Experimental Study of Some Properties of Stuttered Words

1962 ◽  
Vol 5 (4) ◽  
pp. 387-394 ◽  
Author(s):  
Bruce Quarrington ◽  
Jerome Conway ◽  
Nathan Siegel
Keyword(s):  
Experimental Study

Experimental study of total body washout employing extracorporeal circulation and hypothermia

1974 ◽  
Vol 126 (2) ◽  
pp. 243-248
Author(s):  
A WAKABAYASHI ◽  
T KUBO ◽  
K CHARNEY ◽  
Y NAKAMURA ◽  
J CONNOLLY
Keyword(s):  
Experimental Study ◽  
Extracorporeal Circulation ◽  
Total Body

Gastric Freezing: An Experimental Study

1963 ◽  
Vol 45 (3) ◽  
pp. 374-383 ◽  
Author(s):  
Donald C. McIlrath ◽  
George A. Hallenbeck ◽  
Hubert A. Allen ◽  
Charles V. Mann ◽  
Edward J. Baldes ◽  
...  
Keyword(s):  
Experimental Study
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