Some studies on safe maximum packing of live agents in crowds or containers
O. Córdoba–Rodríguez, M. del Castillo–Mussot*, and J.A. Montemayor–Aldrete
Instituto de Física, Universidad Nacional Autónoma de México, Apartado Postal 20–364 México, D.F. 01000 México. e–mail: *marcelodlcstll@yahoo.com
Recibido el 3 de julio de 2009
Aceptado el 24 de noviembre de 2009
Abstract
We study the geometrical and physical conditions for maximizing the safe packing of live agents in crowds or in containers, like wagons or subways. In order to accommodate small children in interstitial spaces among adults, we firs approximate standing–up people, as observed from above, as circles or ellipses. According to our results, in very crowded conditions babies are better protected only among "athletic" adults (in the sense that their shoulder–shoulder lateral distance is sufficientl larger than their lateral waist) by positioning them on the adults flan at kidney level. In several adults we applied sustained pectoral or thoracic pressure in order to fin the applied force dependence of the chest compression, and the maximum chest compression before not being able to breathe. For every five people barely fittin in a container, we can barely accommodate one more person, due to the chest compression of all persons. Practical recommendations are given in very crowded situations.
Keywords: Granular systems; medical physics; elasticity; pressure or forces in macroscopic solids.
Resumen
Estudiamos las condiciones geométricas y físicas para maximizar el transporte seguro de agentes vivos en contenedores, como en vagones o metros subterráneos. Para acomodar a niños pequeños en espacios intersticiales entre adultos, primero aproximamos a las personas vistas desde arriba, como círculos o elipses. Según nuestros resultados, en aglomeraciones muy densas los bebés están mejor protegidos solo entre los adultos "atléticos" colocándolos a un costado a la altura de los ríñónes. En varios adultos aplicamos presión pectoral o torácica sostenida para encontrar la dependencia de la compresión pectoral en la fuerza y la máxima compresión pectoral antes de no poder respirar. Por cada cinco personas apenas ajustadas en un contenedor, podemos acomodar a otra persona más, comprimiendo los pechos de todos. Se dan recomendaciones prácticas en aglomeraciones muy densas.
Descriptores: Sistemas granulares; física médica; elasticidad; presión o fuerzas en sólidos macroscópicos.
PACS: 45.70.–n; .90.+y; 91.60.Ba; 46.00.00; 74.62.Fj
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