scholarly journals Comments on “The Determination of View-Factors in Urban Canyons”

Author(s):  
D. G. Steyn ◽  
T. J. Lyons
Keyword(s):  
1968 ◽  
Vol 5 (2) ◽  
pp. 139-140 ◽  
Author(s):  
William E. Reifsnyder

Author(s):  
D. G. Steyn ◽  
J. E. Hay ◽  
Ian D. Watson ◽  
Glenn T. Johnson

2009 ◽  
Vol 36 (11-12) ◽  
pp. 1681-1688 ◽  
Author(s):  
Santosh B. Bopche ◽  
Arunkumar Sridharan

2018 ◽  
Vol 9 (1) ◽  
pp. 115-128
Author(s):  
Grzegorz JĄCZEK ◽  
Józef GACEK ◽  
Wojciech FURMANEK

This work presents a fuze setting method for ammunition for cannons and grenade launchers with a calibre of 25 to 40 mm, with a projectile body, that generates fragments by burst, on its trajectory during projectile flight. This setting method is based on fuze data delivery with a number of projectile turns between a muzzle and accurately predetermined point on its trajectory. The proposed method for fuzes setting is intended for precise determination of the distance travelled by the projectile, and should provide an alternative method for time setting fuzes. The method utilizes the phenomenon when the projectile, launched from the rifling barrel, overcomes a distance, in one turn path, equal to the barrel rifling pitch. This distance, independent of the projectile muzzle’s velocity and the number of turns made by the projectile, will determine the path travelled by it. In this work, important factors were presented, that apply to functioning the fuzes with spin detecting and turns counting features and that were omitted in descriptions of similar fuzes’ known solutions. These factors are: "idle gun elevation angles", when signal is not generated; electromagnetic interferences, affecting quantity of impulses that are counted and random projectile initial orientation after a gun loading, in relation to projectile airbust point on a trajectory. Consideration of those important, from the ballistic point of view, factors in fuze construction makes it an innovative one. This publication shows also a proposition of the fuze electronic subassembly, that includes all of the questions that were mentioned.


2010 ◽  
Vol 132 (7) ◽  
Author(s):  
T. Walker ◽  
S.-C. Xue ◽  
G. W. Barton

A ray-tracing method is presented for numerically determining radiative view factors in complex three-dimensional geometries. This method uses a set of “primitive” shapes to approximate the required geometry together with a Monte Carlo simulation to track the fate of randomized rays leaving each surface. View factors were calculated for an operational fiber drawing furnace using both numerical integration and ray-tracing methods. Calculated view factor profiles were essentially identical above a ray density of 105 per unit area. Run times for the ray-tracing method were considerable longer, although the setup time to describe a new geometry is very short and essentially independent of system complexity.


Author(s):  
Glenn T. Johnson ◽  
Ian D. Watson
Keyword(s):  

1966 ◽  
Vol 25 ◽  
pp. 93-97
Author(s):  
Richard Woolley

It is now possible to determine proper motions of high-velocity objects in such a way as to obtain with some accuracy the velocity vector relevant to the Sun. If a potential field of the Galaxy is assumed, one can compute an actual orbit. A determination of the velocity of the globular clusterωCentauri has recently been completed at Greenwich, and it is found that the orbit is strongly retrograde in the Galaxy. Similar calculations may be made, though with less certainty, in the case of RR Lyrae variable stars.


1999 ◽  
Vol 190 ◽  
pp. 549-554
Author(s):  
Nino Panagia

Using the new reductions of the IUE light curves by Sonneborn et al. (1997) and an extensive set of HST images of SN 1987A we have repeated and improved Panagia et al. (1991) analysis to obtain a better determination of the distance to the supernova. In this way we have derived an absolute size of the ringRabs= (6.23 ± 0.08) x 1017cm and an angular sizeR″ = 808 ± 17 mas, which give a distance to the supernovad(SN1987A) = 51.4 ± 1.2 kpc and a distance modulusm–M(SN1987A) = 18.55 ± 0.05. Allowing for a displacement of SN 1987A position relative to the LMC center, the distance to the barycenter of the Large Magellanic Cloud is also estimated to bed(LMC) = 52.0±1.3 kpc, which corresponds to a distance modulus ofm–M(LMC) = 18.58±0.05.


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