Saving energy through changing light: The impact of illumination on thermal comfort

The ‘Hue-Heat Hypothesis’ states that light with wavelengths predominantly at the red end of the spectrum (or of a low colour temperature) are felt as warmer, whilst light with wavelengths mainly in the blue end (or of a high colour temperature) are felt as cooler. If confirmed, the Hue-Heat-Hypothesis could be a powerful tool for energy savings: Temperatures could be lowered under a reddish light in the heating season. Conversely, less air-conditioning might be needed during the cooling season if higher temperatures were accepted under a bluish light. Even a transitory effect would be beneficial in managing power demand by allowing building temperatures to drift over a wider range of temperatures before heating or cooling was required. We used an experimental design to study the Hue-Heat-Hypothesis. Testing took place in a climate chamber, in which ambient temperature, relative humidity, and air speed can be controlled. We installed a LED-lighting system in the chamber covering the range of correlated colour temperatures from 2700K, a warm, reddish light, to 6500K which appears bluish-cold. Participants (age range 18 to 35 years) were exposed to combinations of colour temperature and ambient temperature and completed standard thermal comfort surveys at specific time-points. Prior to testing, participants filled in a survey that asked about other factors potentially impacting on thermal comfort. In Study 1, temperature in the climate chamber was cooled continuously from 24°C to 20°C over a 60-minute period. Comfort ratings were obtained every 10 minutes. Participants (N = 32) were either exposed to a colour temperature of 2700K or 6500K (between-subjects design). Thermal comfort was higher under the warm colour temperature (2700K) than under the cold one (6500K). This difference was particularly pronounced for temperatures around 21 and 22°C. For the same subjective thermal comfort rating, ambient temperatures differed by around half a degree under the different lighting conditions. The magnitude of the effect varied with temperature (greatest effects observed around 22-23˚C) and by comfort question asked. In Study 2, a within-subject design was used. Subjects were exposed to three different lights (2700K, 4440K,6500 K) with temperature decreasing from 23°C to 19°C. Preliminary results were similar to those of Study 1 with higher comfort under the warm-appearing light. Comfort ratings under the medium colour temperature of 4400K were positioned between the higher ratings obtained for 2700K and lower ratings for 6500K, again, only in a limited corridor of ambient temperature. In Study 3, light was changed gradually from a cold to a warm colour temperature whilst ambient temperature decreased from 23°C to 19°C. Testing is on-going, but initial results indicate that the changes in self-reported comfort under decreasing temperatures are slower in the condition of changing light dynamically than under a stable Our studies support the Hue-Heat-Hypothesis. Varying the ambient light has an effect on thermal comfort and hence may be a suitable tool for energy savings and reducing of peak power demand

Nanodrawing of aligned single carbon nanotubes with a nanopen

Single-walled carbon nanotubes (SWCNTs) are considered pivotal components for molecular electronics. Techniques for SWCNT lithography today lack simplicity, flexibility, and speed of direct, oriented deposition at specific target locations. In this paper SWCNTs are directly drawn and placed with chemical identification and demonstrated orientation using fountain pen nanolithography (FPN) under ambient conditions. Placement across specific electrical contacts with such alignment is demonstrated and characterized. The fundamental basis of the drawing process with alignment has potential applications for other related systems such as inorganic nanotubes, polymers, and biological molecules

Integrin α8 Is Abundant in Human, Rat, and Mouse Trophoblasts

Objective: Integrins exert regulatory functions in placentogenesis. Null mutation of certain integrin α subunits leads to placental defects with subsequent fetal growth restriction or embryonic lethality in mice. So far, the placental role of α8 integrin remains to be determined. Methods: Localization of α8 integrin and its ligands, fibronectin (FN) and osteopontin (OPN), was studied by immunohistochemistry in human, rat, and mouse placenta. The vascularization of the placental labyrinth layer of α8 integrin-deficient mice was determined by CD31 staining. In humans, α8 integrin expression was assessed via real-time polymerase chain reaction in healthy placentas, in the placental pathologies such as intrauterine growth restriction (IUGR), preeclampsia, and HELLP-syndrome (hemolysis, elevated liver enzymes, low platelet count), as well as in primary extravillous trophoblasts (EVT) and villous trophoblasts. Results: In humans, α8 integrin was detected in first and third trimester syncytiotrophoblast and EVT. Although OPN showed the same localization, FN was observed in EVT only. No expressional changes in α8 integrin were detected in the placental pathologies studied. Rodent placenta showed α8 integrin expression in giant cells and in the labyrinth layer. The localization of OPN and FN, however, showed species-specific differences. Knockout of α8 integrin in mice did not cause IUGR, despite some reduction in labyrinth layer vascularization. Conclusion: α8 Integrin is expressed in functional placental compartments among its ligands, OPN and/or FN, across species. Although this may point to a regulatory role in trophoblast function, our data from α8 integrin-deficient mice indicated only mild placental pathology. Thus, the lack of placental α8 integrin seems to be largely compensated for

Evaluating assumptions of scales for subjective assessment of thermal environments – Do laypersons perceive them the way, we researchers believe?

International audienc

Evaluating arbitrary strain configurations and doping in graphene with Raman spectroscopy

Raman spectroscopy is a powerful tool for characterizing the local properties of graphene. Here, we introduce a method for evaluating unknown strain configurations and simultaneous doping. It relies on separating the effects of hydrostatic strain (peak shift) and shear strain (peak splitting) on the Raman spectrum of graphene. The peak shifts from hydrostatic strain and doping are separated with a correlation analysis of the 2D and G frequencies. This enables us to obtain the local hydrostatic strain, shear strain and doping without any assumption on the strain configuration prior to the analysis. We demonstrate our approach for two model cases: Graphene under uniaxial stress on a PMMA substrate and graphene suspended on nanostructures that induce an unknown strain configuration. We measured $\omega_\mathrm{2D}/\omega_\mathrm{G} = 2.21 \pm 0.05$ for pure hydrostatic strain. Raman scattering with circular corotating polarization is ideal for analyzing strain and doping, especially for weak strain when the peak splitting by shear strain cannot be resolved

Food and Beverage Options at Highway Rest Areas in North Carolina: A Mixed-Methods Audit and Geospatial Approach

Introduction Each year, millions of people purchase food at highway rest areas. Rest areas are potential sites for health promotion because they are operated by the public sector; they are frequently visited by professional truck drivers, who have a disproportionate burden of chronic disease; and they are easily accessible. To our knowledge, no research has systematically examined the healthfulness of food offerings at rest areas. The objective of this study was to determine the accessibility and healthfulness of food and beverages offered at highway rest areas in North Carolina using a mixedmethods audit and geospatial approach. Methods We conducted a cross-sectional audit of all rest areas offering foods and beverages in North Carolina (N = 30) in summer 2018. We used the Nutrition Environment Measures Survey-Vending (NEMS-V) to record the 1) type, price, and size of all foods and beverages and 2) healthfulness of items offered (based on NEMS-V categorization). Two researchers independently double coded NEMS-V data. We used geospatial analysis to examine proximity of rest areas to food stores. We analyzed data by using univariate and bivariate analysis. Results The mean number of vending machines per site was 8.0 (range, 2-12, standard deviation, 2.8). The healthfulness of offerings varied across sites. Most food items (88.1%; 2,922 of 3,315) and beverage items (63.7%; 1,567 of 2,459) were classified as least healthful. Cold beverage machines had a greater percentage of healthful items (38.2%; 778 of 2,036) than snack machines (11.4%; 374 of 3,270) (P \u3c.001), mainly because of water and diet soda in beverage machines. Conclusion Policy changes are needed to increase the number and presentation of healthful food options at highway rest areas. Policy changes could provide travelers with more healthful options conveniently located along their travel route