As a fundamental study relevant to micro-combustor application, the effects of mixture dilution on the lean extinction characteristics is studied for a stagnation-point flow system with a methane/air mixture over a platinum surface. For steady conditions, the level of flammability extension by surface reaction depends strongly on the mixture dilution, such that the benefit of catalyst-assisted ...

Humans are unique in many respects including being furless, striding bipeds that excel at walking and running long distances in hot conditions. This review summarizes what we do and do not know about the evolution of these characteristics, and how they are related. Although many details remain poorly known, the first hominins (species more closely related to humans than to chimpanzees) apparent...

We present a systematic and quantitative model of huddling penguins. In this mathematical model, each individual penguin in the huddle seeks only to reduce its own heat loss. Consequently, penguins on the boundary of the huddle that are most exposed to the wind move downwind to more sheltered locations along the boundary. In contrast, penguins in the interior of the huddle neither have the spac...

BACKGROUND The plumage of birds is important for flying, insulation and social communication. Contour feathers cover most of the avian body and among other functions they provide a critical insulation layer against heat loss. Feather structure and composition are known to vary among individuals, which in turn determines variation in the insulation properties of the feather. However, the extent ...

Porous media are often used in flame arresters because of the high surface area to volume ratio that is required for flame quenching. However, if the flame is not quenched, the flow obstruction within the porous media can promote explosion escalation, which is a well-known phenomenon in obstacle-laden channels. There are many parallels between explosion propagation through porous media and obst...

Metallized plastic sheeting (m.p.s.) was used in 14 neurosurgical patients and changes in body heat content during surgery compared with those of 14 control patients. All patients, except three in the study group and one in the control group, lost heat by the end of the operation. There was, however, a statistically significant reduction in heat loss in the patients wrapped in m.p.s. Measuremen...