Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

The shape of a perfect fire

08.06.2015

A new Duke theory identifies the height-to-base ratio that helped humanity master fire and migrate across the globe

From ancient Egyptians roasting a dripping cut of beef next to the Great Pyramid of Giza to a Boy Scout learning to build a log cabin fire in his backyard, everyone builds fires with the same general shape.


Today in Nature Scientific Reports, engineering professor Adrian Bejan shows that the best campfires are roughly as tall as they are wide. The shape is the most efficient for the flow of air and heat.

"Our bonfires are shaped as cones and pyramids, as tall as they are wide at the base. They look the same in all sizes, from the firewood in the chimney, to the tree logs and wooden benches in the center of the university campus after the big game," Bejan said.

Courtesy of Duke University

And now we know why.

In a study published in Nature Scientific Reports on June 8, Adrian Bejan, the J.A. Jones professor of mechanical engineering at Duke University, shows that, all other variables being equal, the best fires are roughly as tall as they are wide. This is why, he argues, everyone has built fires that basically look the same since the dawn of time.

... more about:
»Egyptians »Nature »evolve »heat flow »movement »pyramids

'Humans from all eras have been relying on this design,' said Bejan. 'The reason is that this shape is the most efficient for air and heat flow. Our success in building fires in turn made it possible for humans to migrate and spread across the globe heat flow from fire facilitates the movement and spreading of human mass on the globe, which is a direct prediction of the Constructal Law.'

In 1996, Bejan penned the Constructal Law that postulates that movement -- or 'flow' -- systems such as trees, rivers or air currents evolve into configurations that provide easier and easier access to flows. Now internationally recognized, the law is increasingly finding applications in improving design and maximizing efficiency of manmade systems.

Bejan continued, 'Our bonfires are shaped as cones and pyramids, as tall as they are wide at the base. They look the same in all sizes, from the firewood in the chimney, to the tree logs and wooden benches in the center of the university campus after the big game. They look the same as the pile of charcoal we make to grill meat. And now we know why.'

So the next time you're out camping and want to build the perfect fire, now you know what general shape it should take.

But you already knew that, didn't you?

###

'Why humans build fires shaped the same way.' Adrian Bejan. Nature Scientific Reports, 2015; 5:11270. DOI: 10.1038/srep11270

Media Contact

Ken Kingery
ken.kingery@duke.edu
919-660-8414

 @DukeU

http://www.duke.edu 

Ken Kingery | EurekAlert!

Further reports about: Egyptians Nature evolve heat flow movement pyramids

More articles from Materials Sciences:

nachricht Mat4Rail: EU Research Project on the Railway of the Future
23.02.2018 | Universität Bremen

nachricht Atomic structure of ultrasound material not what anyone expected
21.02.2018 | North Carolina State University

All articles from Materials Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Attoseconds break into atomic interior

A newly developed laser technology has enabled physicists in the Laboratory for Attosecond Physics (jointly run by LMU Munich and the Max Planck Institute of Quantum Optics) to generate attosecond bursts of high-energy photons of unprecedented intensity. This has made it possible to observe the interaction of multiple photons in a single such pulse with electrons in the inner orbital shell of an atom.

In order to observe the ultrafast electron motion in the inner shells of atoms with short light pulses, the pulses must not only be ultrashort, but very...

Im Focus: Good vibrations feel the force

A group of researchers led by Andrea Cavalleri at the Max Planck Institute for Structure and Dynamics of Matter (MPSD) in Hamburg has demonstrated a new method enabling precise measurements of the interatomic forces that hold crystalline solids together. The paper Probing the Interatomic Potential of Solids by Strong-Field Nonlinear Phononics, published online in Nature, explains how a terahertz-frequency laser pulse can drive very large deformations of the crystal.

By measuring the highly unusual atomic trajectories under extreme electromagnetic transients, the MPSD group could reconstruct how rigid the atomic bonds are...

Im Focus: Developing reliable quantum computers

International research team makes important step on the path to solving certification problems

Quantum computers may one day solve algorithmic problems which even the biggest supercomputers today can’t manage. But how do you test a quantum computer to...

Im Focus: In best circles: First integrated circuit from self-assembled polymer

For the first time, a team of researchers at the Max-Planck Institute (MPI) for Polymer Research in Mainz, Germany, has succeeded in making an integrated circuit (IC) from just a monolayer of a semiconducting polymer via a bottom-up, self-assembly approach.

In the self-assembly process, the semiconducting polymer arranges itself into an ordered monolayer in a transistor. The transistors are binary switches used...

Im Focus: Demonstration of a single molecule piezoelectric effect

Breakthrough provides a new concept of the design of molecular motors, sensors and electricity generators at nanoscale

Researchers from the Institute of Organic Chemistry and Biochemistry of the CAS (IOCB Prague), Institute of Physics of the CAS (IP CAS) and Palacký University...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

2nd International Conference on High Temperature Shape Memory Alloys (HTSMAs)

15.02.2018 | Event News

Aachen DC Grid Summit 2018

13.02.2018 | Event News

How Global Climate Policy Can Learn from the Energy Transition

12.02.2018 | Event News

 
Latest News

Basque researchers turn light upside down

23.02.2018 | Physics and Astronomy

Finnish research group discovers a new immune system regulator

23.02.2018 | Health and Medicine

Attoseconds break into atomic interior

23.02.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>