The Usambara effect and its interaction with other colour change phenomena

AbstractSustainability in electronics has a growing importance due to, e.g. increasing electronic waste, and global and European sustainability goals. Printing technologies and use of paper as a substrate enable manufacturing of sustainable electronic devices for emerging applications, such as the multi-layer anti-counterfeit label presented in this paper. This device consisted of electrochromic display (ECD) element, NFC (near field communication) tag and circuitry, all fully roll-to-roll (R2R) printed and assembled on plastic-free paper substrate, thus leading to a sustainable and recyclable device. Our setup uses harvested energy from HF field of a smartphone or reader, to switch an electrochromic display after rectification to prove authenticity of a product. Our novelty is in upscaling the manufacturing process to be fully printable and R2R processable in high-throughput conditions simulating industrial environment, i.e. in pilot scale. The printing workflow consisted of 11 R2R printed layers, all done in sufficient quality and registration. The printed antennas showed sheet resistance values of 32.9±1.9 mΩ/sq. The final yield was almost 1500 fully printed devices, and in R2R assembly over 1400 labels were integrated with 96.5% yield. All the assembled tags were readable with mobile phone NFC reader. The optical contrast (ΔE*) measured for the ECDs was over 15 for all the printed displays, a progressive switching time with a colour change visible in less than 5 s. The smart tag is ITO-free, plastic-free, fully printed in R2R and has a good stability over 50 cycles and reversible colour change from light to dark blue.

Download Full-text

Evolutionary Changes in LUMINOUS STARS

Highlights of Astronomy ◽

10.1017/s1539299600020979 ◽

1998 ◽

Vol 11 (1) ◽

pp. 346-346

Author(s):

E. Zsldos

Keyword(s):

Light Curve ◽

19Th Century ◽

Stellar Evolution ◽

Colour Change ◽

Light Curves ◽

Appreciable Change ◽

Luminous Blue Variables ◽

Secular Changes ◽

Evolutionary Changes ◽

The 19Th Century

The light curves of luminous stars often show spectacular secular changes which can be connected to stellar evolution. Such events are, e.g. the outbursts of P Cygni in the 17th century and 77 Carinae in the last century. Both stars belong to the Luminous Blue Variables, but these changes are not restricted to blue stars. The light curve of HR 8752 (V509 Cassiopeiae) shows a certain similarity to that of the former two stars. When it was first catalogued in the middle of the 19th century, it had been a 6m star. During 100 years the star showed a secular brightening of lm. A similar yellow hypergiant, p Cassiopeiae produced at least two outbursts this century, though both have smaller amplitudes than it is in the case of the LBVs. Moreover, these yellow variables also have an apparently secular colour change: the B − V colour of HR 8752 is decreasing while that of ρ Cassiopeiae is increasing. In both cases evolutionary changes are possible but one cannot exclude other causes. Besides these well studied stars there are several other yellow hypergiants with promising light curves. One of the most interesting cases seems to be R Puppis, which was discovered to be variable in the last century, but then did not show any appreciable change in the following 70-80 years. In the late 1970s, however, it began to vary once more.

Download Full-text

COLOUR CHANGE IN C.T. HALOTESTIN

The Medical Journal of Australia ◽

10.5694/j.1326-5377.1980.tb135015.x ◽

1980 ◽

Vol 1 (9) ◽

pp. 443-443

Keyword(s):

Colour Change

Download Full-text

Efficient photorelease of carbon monoxide from a luminescent tricarbonyl rhenium(i) complex incorporating pyridyl-1,2,4-triazole and phosphine ligands

Dalton Transactions ◽

10.1039/d0dt03577g ◽

2021 ◽

Author(s):

Ángel D. Hernández Mejías ◽

Alexandre Poirot ◽

Meriem Rmili ◽

Nadine Leygue ◽

Mariusz Wolff ◽

...

Keyword(s):

Carbon Monoxide ◽

Colour Change ◽

Phosphine Ligands

In this new Re(i) PhotoCORM, the efficient photoproduction of carbon monoxide is visualized through a strong colour change of the emitted phosphorescence.

Download Full-text

Perceiving numerosity does not cause automatic shifts of spatial attention

Experimental Brain Research ◽

10.1007/s00221-021-06185-7 ◽

2021 ◽

Author(s):

Michele Pellegrino ◽

Mario Pinto ◽

Fabio Marson ◽

Stefano Lasaponara ◽

Fabrizio Doricchi

Keyword(s):

Spatial Attention ◽

Colour Change ◽

Simultaneous Presentation ◽

Variable Delay ◽

Large Magnitude ◽

Small Magnitude ◽

Spatial Component ◽

Speed Up ◽

The Right

AbstractIt is debated whether the representation of numbers is endowed with a directional-spatial component so that perceiving small-magnitude numbers triggers leftward shifts of attention and perceiving large-magnitude numbers rightward shifts. Contrary to initial findings, recent investigations have demonstrated that centrally presented small-magnitude and large-magnitude Arabic numbers do not cause leftward and rightward shifts of attention, respectively. Here we verified whether perceiving small or large non-symbolic numerosities (i.e., clouds of dots) drives attention to the left or the right side of space, respectively. In experiment 1, participants were presented with central small (1, 2) vs large-numerosity (8, 9) clouds of dots followed by an imperative target in the left or right side of space. In experiment 2, a central cloud of dots (i.e., five dots) was followed by the simultaneous presentation of two identical dot-clouds, one on the left and one on the right side of space. Lateral clouds were both lower (1, 2) or higher in numerosity (8, 9) than the central cloud. After a variable delay, one of the two lateral clouds turned red and participants had to signal the colour change through a unimanual response. We found that (a) in Experiment 1, the small vs large numerosity of the central cloud of dots did not speed up the detection of left vs right targets, respectively, (b) in Experiment 2, the detection of colour change was not faster in the left side of space when lateral clouds were smaller in numerosity than the central reference and in the right side when clouds were larger in numerosity. These findings show that perceiving non-symbolic numerosity does not cause automatic shifts of spatial attention and suggests no inherent association between the representation of numerosity and that of directional space.

Download Full-text

O15 Using a smartphone app to characterise and quantify skin colour changes in Raynaud's attacks

Rheumatology ◽

10.1093/rheumatology/keab246.014 ◽

2021 ◽

Vol 60 (Supplement_1) ◽

Author(s):

Graham Dinsdale ◽

Joanne Manning ◽

Ariane Herrick ◽

Mark Dickinson ◽

Christopher Taylor

Keyword(s):

Mobile Phone ◽

Strong Association ◽

Colour Change ◽

Objective Measure ◽

Skin Colour ◽

Smartphone App ◽

Limiting Factor ◽

Bhattacharyya Distance ◽

Automated Method ◽

The Mean

Abstract Background/Aims The lack of objective outcome measures for Raynaud's phenomenon (RP) has been a major limiting factor in development of effective treatments. At present, the Raynaud's Condition Score (RCS) is the only validated outcome measure, and is highly subjective. Mobile phone technology could provide a way forward. We have developed a smartphone app for RP monitoring that guides the patient through the process of capturing images of their hands during RP episodes, as well as capturing other data through post-attack and daily questionnaires. One of the objectives of our research programme (reported here) was to compare digital image (photographic) parameters to the RCS. Methods 40 patients with RP (8 with primary RP, 32 with RP secondary to systemic sclerosis) were recruited (40 female, median age (range): 57 years (25-74), median (range) duration of RP symptoms: 17 (0-53) years). Patients were given a smartphone handset with a pre-installed Raynaud’s Monitoring app and were trained on how to use it/take usable photographs. They were then asked to take photographs of RP attacks over a 14 day period and also to record the RCS for each episode. The app specifically prompts the patient to take a picture of their hand every minute during an attack, until confirmation is given that the attack is complete. At a 2nd visit, the handsets, images, and data were collected for analysis. The mean colour change during each RP attack was quantified (semi-automated method) by the Bhattacharyya distance (BD) in colour space between a region of interest (e.g. a section of a digit) and a control region (dorsal hand). BD was then compared to the RCS using ANOVA, after controlling for patient variability in the range of RCS values used by each patient. Results A total of 3,030 images were collected, describing 229 RP attacks. The median RCS reported was 6 (inter-quartile range [IQR]: 4), while the median for BD was 5.6 (IQR 3.2). ANOVA showed that measured values of the mean image BD were significantly different when different values of RCS were recorded by the patient (p < 0.001), i.e. attacks where patients selected different values of RCS had significantly different values of BD. Across all attacks/patients the F-value from ANOVA for RCS was 76.2, suggesting that the variation in BD for different values of RCS is much greater than the variation in BD for any one value of RCS. Conclusion Patients successfully used a smartphone app to collect photographs and data during episodes of RP. A strong association was found between skin colour change (via BD) and the gold-standard RCS. Mobile phone-documented colour change therefore has potential as an objective measure of RP. Further validation work is now required, as well as studies examining sensitivity to change. Disclosure G. Dinsdale: None. J. Manning: None. A. Herrick: None. M. Dickinson: None. C. Taylor: None.

Download Full-text