Qualitative Experimental Verification of the Change of Burning Rate of Rocket Powders with Radiation Path Length

1948 ◽  
Vol 19 (6) ◽  
pp. 511-513 ◽  
Author(s):  
S. S. Penner
Keyword(s):  
Burning Rate ◽  
Experimental Verification ◽  
Path Length ◽  
Radiation Path

scholarly journals Personal UV exposure on a ski-field at an alpine site

2008 ◽  
Vol 8 (1) ◽  
pp. 2745-2769 ◽  
Author(s):  
A. M. Siani ◽  
G. R. Casale ◽  
H. Diémoz ◽  
G. Agnesod ◽  
M. G. Kimlin ◽  
...  
Keyword(s):  
Uv Radiation ◽  
Biological Markers ◽  
Path Length ◽  
Uv Exposure ◽  
Individual Response ◽  
Mountainous Areas ◽  
Sunscreen Use ◽  
Exposure Ratio ◽  
First Time ◽  
Radiation Path

Abstract. Mountain sites experience enhanced ambient UV radiation levels due to the concurrent effects of shorter radiation path-length, low aerosol load and high reflectivity of the snow surfaces. This study was encouraged by the possibility to collect data of personal UV exposure in the mountainous areas of Italy, for the first time. Personal UV exposure (expressed in terms of Exposure Ratio, ER) of two groups of volunteers (ski instructors and skiers) at the Alpine site of La Thuile (Valle d'Aosta region, Italy) was assessed using polysulphone dosimetry which was tested in a mountainous snow-covered environment. In addition measurements of biological markers of individual response to UV exposure such as skin colorimetric parameters were carried out. It was found that snow and altitude of study site affect calibration curves of polysulphone dosimeters in comparison to a situation without snow. The median ER, taking into account the whole sample, is 0.60 in winter, with a range of 0.29 to 1.46, and 1.02 in spring, ranging from 0.46 to 1.72. There are no differences in exposures across skiers and instructors in spring while in winter skiers experience lower values. UV exposures are not sensitive to the use of sunscreen across instructor/skier group by day or by seasons or by photo-type. With regard to colorimetric parameters, the main result was that both skiers and instructors had on average significantly lower values of L* and b* after exposure i.e. becoming darker but the inappropriate sunscreen use did not reveal any changes in skin colorimetric parameters except in one spring day. In conclusions UV intensities on the ski-fields are often significantly higher than those on horizontal surfaces. Given the high levels of exposure observed in the present study, dedicated public heath messages on the correct sunscreen use should be adopted.

The Effect of Path Length and Display Size on Memory for Spatial Information

2012 ◽  
Vol 59 (3) ◽  
pp. 147-152 ◽  
Author(s):  
Katherine Guérard ◽  
Sébastien Tremblay
Keyword(s):  
Path Length ◽  
Potential Role ◽  
Spatial Information ◽  
Recall Performance ◽  
Minor Role ◽  
Length Effect ◽  
Serial Memory ◽  
Fixed Reference ◽  
A Minor

In serial memory for spatial information, some studies showed that recall performance suffers when the distance between successive locations increases relatively to the size of the display in which they are presented (the path length effect; e.g., Parmentier et al., 2005) but not when distance is increased by enlarging the size of the display (e.g., Smyth & Scholey, 1994). In the present study, we examined the effect of varying the absolute and relative distance between to-be-remembered items on memory for spatial information. We manipulated path length using small (15″) and large (64″) screens within the same design. In two experiments, we showed that distance was disruptive mainly when it is varied relatively to a fixed reference frame, though increasing the size of the display also had a small deleterious effect on recall. The insertion of a retention interval did not influence these effects, suggesting that rehearsal plays a minor role in mediating the effects of distance on serial spatial memory. We discuss the potential role of perceptual organization in light of the pattern of results.

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