MASTER THESIS Biomimetic potential of sponge ... - IAP/TU Wien

Importantly, social jetlag is closely correlated with obesity and likely other metabolic
phenomena according to the wide database of Roenneberg and colleagues (2012). From
1980 to 2008, obesity has doubled worldwide and 65% percent of the world population (of
more than seven billion people) live in countries where more people die because of obesity
and overweight than because of underweight (www.who.int/topics/obesity/en/)(Foster,
2012). Hence, if the social jetlag theory is further corroborated, better entrainement or other
measures to realign social and circadian clocks seem an imperative. In this context it is
relevant to state that the photoreceptors likely involved in the entrainment of the circadian
rhythm absorb blue light (446-488 nm) (Brainard & Hanafin, 2004) (Bellia et al., 2011).
This factor relates specifically to workplaces, because working hours usually are during
daylight time, which accordingly makes natural light a good option for lighting. There have
been reported numerous other health related concerns with regards to illumination of
workspaces (reviewed in (Wilkins, 1993)). These include problems with low-frequency
magnetic fields and rapid variation in luminous intensity (including flicker), both examples
that are not a concern in daylighting.
A very different concern is the ambiance of an office. As has been discussed by Kaplen
(1975) the design of an office space is often used to convey a message about the identity
and aspirations of a company. Light and lighting systems can help to improve the perceived
value of such a space. Since novel systems for lighting, like most innovative systems, require
higher investment from the client, it is desirable to offer the client not only functionality and
aesthetic design, but also the possibility to express their identity or philosophy.
Obviously, there are great local differences in the incidence of sunlight and other factors
influencing the availability of daylight for lighting. For planning and simulation purposes
different fraction of external illuminance (availability of light) are commonly distinguished,
e.g. direct normal (DN) (Figure 24) and global horizontal (GH) illuminance. GH illuminance in
this case accounts for all scattered and reflected light. Numerical values for these
parameters, as well as other data for illuminance and solar radiation, can be obtained with
good temporal and regional (20 km steps) from (free) websites (soda-is.com). Distinguishing
different types of light (illuminance) is essential in this context, because some daylight
guidance systems can only make use of direct normal irradiation, making these
inappropriate for places like London. The same system might however outperform other
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