Radiative contribution to thermal conductance in animal furs and other woolly insulators

Simonis, Priscilla; Rattal, Mourad; Oualim, El Mostafa; Mouhse, Azeddine; Vigneron, Jean‐Pol

doi:10.1364/oe.22.001940

Cited by 62 publications

(15 citation statements)

References 16 publications

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“…Micro-scale structures of peacock feathers comprise complex branching patterns of barbs and barbules that depend on their surface curvature, twist, orientation distributions, etc., and change during feather growth [1,6,9,10,47,48]. The spatial average over many barbules smoothes the reflectance spectra created by sub-micron 2D photonic crystal structures within the cortex surface of each single barbule and spread reflected light over a wide angular range [1,9,11].…”

Section: Resultsmentioning

confidence: 99%

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Classification of peacock feather reflectance using principal component analysis similarity factors from multispectral imaging data

Medina¹,

Díaz²,

Vukusic³

2015

Opt. Express

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Iridescent structural colors in biology exhibit sophisticated spatially-varying reflectance properties that depend on both the illumination and viewing angles. The classification of such spectral and spatial information in iridescent structurally colored surfaces is important to elucidate the functional role of irregularity and to improve understanding of color pattern formation at different length scales. In this study, we propose a non-invasive method for the spectral classification of spatial reflectance patterns at the micron scale based on the multispectral imaging technique and the principal component analysis similarity factor (PCASF). We demonstrate the effectiveness of this approach and its component methods by detailing its use in the study of the angle-dependent reflectance properties of Pavo cristatus (the common peacock) feathers, a species of peafowl very well known to exhibit bright and saturated iridescent colors. We show that multispectral reflectance imaging and PCASF approaches can be used as effective tools for spectral recognition of iridescent patterns in the visible spectrum and provide meaningful information for spectral classification of the irregularity of the microstructure in iridescent plumage.

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Section: Resultsmentioning

confidence: 99%

“…Its constituent feather barbules lack melanin rods [ Fig. 1(f)] and its white color appearance is principally produced by broadband scattering in its keratin matrix [45][46][47]. We follow this by applying PCASF to the comparison of spatial reflectance patterns produced by feathers from an adult and a young peacock [Figs.…”

Section: Introductionmentioning

confidence: 99%

Classification of peacock feather reflectance using principal component analysis similarity factors from multispectral imaging data

Medina¹,

Díaz²,

Vukusic³

2015

Opt. Express

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“…Interestingly, few examples of high-transport solid thermal materials exist in nature, in contrast to the opposite extreme of highly insulating structures, such as animal fur (Simonis et al, 2014). This state of affairs is likely the result of the peculiarly good thermal transport properties of water -by far the most abundant natural liquid.…”

Section: Adaptable Thermofluidic Transportmentioning

confidence: 99%

Contemporary Challenges for Thermal and Mass Transport Technologies: A Perspective on Twenty-First Century Opportunities for the Field

Fisher

2016

Front. Mech. Eng.

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The development of thermal and mass transport as a subject of scientific study holds a central place in the origin and advancement of the Industrial Revolution by enabling the steam engine, which in turn provided unprecedented levels of power and speed for transportation, material processing, and eventually the distribution of electricity. Even earlier, elementary understanding of heat and mass transfer were crucial elements in providing for human safety and comfort, as well as food preservation via cooking and drying. Given this rich and diverse history, a logical question is: how much more of this subject remains to be discovered and explored? One answer would point to nuances of how heat and mass flow occurs at different scales through various material solid and fluid hosts, new forms of which are constantly being discovered and developed (Bergman et al., 2008). However, such a perspective seems relatively narrow in comparison to the outsize history of impact in the field, yet at the same time global grand challenge problems, such as clean energy and water, food security, or eradication of disease are too general to have useful meaning for the present purpose. Instead, we consider here how improved understanding of the details of thermal and mass transport might rekindle a new set of discoveries and technologies with broad global impact. tranSient and nOn-eQUiliBriUM prOceSSeSA useful starting point for imagining the possibilities of transformative discoveries in the area of transport processes is the semiconductor industry. Borne of a seemingly simple yet profound combination of materials built into a unique device, the solid-state transistor has served as the genesis of multiple industries, ranging from personal computing to telecommunications (Brinkman et al., 1997). One of the crucial insights to the development of integrated circuits (ICs) was that individual devices could be operated away from thermodynamic equilibrium in a repeated and coordinated manner to produce a greater overall effect than the "sum of their parts. " With such developments arose other specialized circuit elements such as micro-capacitors and dynamic memory devices that, along with a set of community-driven and shared design tools (Dutton and Yu, 2012), have enabled the simple transistor to form the basis of ICs that now touch nearly every technology-based device and product.In comparison, the study of transport phenomena has focused strongly on near-equilibrium and steady-or quasi-steady-state processes. This emphasis is apparent in virtually any textbook on heat, mass, and/or fluid transport, largely because of the myriad complexities produced by nonequilibrium thermodynamics and transient dynamics (Groot and Mazur, 1962). One important example of non-equilibrium behavior involves the fast collection of "hot carriers" as proposed

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“…But she claims her research shows that hairs reflect infrared light, so contributing to the significant insulating power of polar bear fur. 3 Together with colleagues from the University of Hassan I in Morocco, Simonis created a computer model consisting of a hot and a cold thermostat that roughly simulated an animal's body and the outside environment. The two thermostats were separated by an empty space into which the researchers added 'radiative shields' that could mimic individual hairs in a fur coat.…”

Section: Fur and Feathersmentioning

confidence: 99%

Trapped air

2014

Chemistry & Industry

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Radiative contribution to thermal conductance in animal furs and other woolly insulators

Cited by 62 publications

References 16 publications

Classification of peacock feather reflectance using principal component analysis similarity factors from multispectral imaging data

Classification of peacock feather reflectance using principal component analysis similarity factors from multispectral imaging data

Contemporary Challenges for Thermal and Mass Transport Technologies: A Perspective on Twenty-First Century Opportunities for the Field

Trapped air

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