• Wind and Structures
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• v.15 no.4
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• pp.345-354
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• 2012

This work discusses the wind stability requirements specified by UN Reg. 27 on emergency car warning triangles, which are of mandatory use in many countries. Wind tunnel experiments have been carried out in order to determine aerodynamic coefficients of commercial warning triangles and the friction coefficients between the triangle legs and an asphalt base that fulfils the roughness requirements stated by Reg. 27 for wind stability certification. The wind stability specifications for warning triangles are reviewed, compared with pressure field measurements and discussed. Results of wind tunnel tests and comparison with field measurements reported in the literature show that the requirements could be excessively conservative.

• Journal of Internet of Things and Convergence
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• v.4 no.1
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• pp.37-41
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• 2018

This paper examines smart warning triangles to prevent secondary accidents on roads. After a traffic accident on the road, a safety tripod must be installed to notify the accident. However, it can cause secondary accidents during warning triangle installation. To solve this problem, a smart warning triangle was proposed and implemented. A smart warning triangle acts as a triangle through a logo light projector when it detects an impact. Arduino functions as an impact detector and a logo light projector. The proposed smart safety tripod is expected to help prevent secondary accidents by acting as a safety tripod if the brightness of illumination is complemented.

• Journal of architectural history
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• v.1 no.1 s.1
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• pp.205-217
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• 1992

For all the variety of past studies on the pyramids of Old Kingdom of Egypt, they still basically remain in 'enigma and mystery' as Giedion rightly puts in. This paper deals directly with the three most obvious facts about the pyramids : their cardinal orientation, the varying slopes, and above all, their magnitude. The prominent triangles of their once polished faces were there to be seen from the Nile valley as they shined or shaded under the Sun. The northern faces, especially, went in and out of the Sun in accordence with the seasonal variation of the solar declination, The steeper northern faces which turned into shade in high summer noon could have been warning signs of oncoming inundation of Nile, and the milder slopes that suddenly began to shine in some early spring noons could have been the vernal alarms to awaken the peasants to their timely toil on the fresh land. Dates and hours of insolation on the northern faces of pyramids are graphically and numerically computed.