Role of ambient wavelength, shell size and pigmentation intensity in the heating of Mediterranean Theba pisana (Eupulmonata: Helicidae)

2020 ◽  
Vol 86 (3) ◽  
pp. 249-253
Author(s):  
Tatjana Tull ◽  
Danina Schmidt ◽  
Heinz-R Köhler

ABSTRACT Theba pisana is a polymorphic land snail widely used in ecophysiological research on the biological significance of solar irradiation. We investigated whether, taking size into account, differently pigmented morphs of a Mediterranean population of T. pisana influence the snails’ heating under different wavelengths. We used a laboratory set-up comprising light-emitting diodes emitting visible light of defined wavelengths and quantified shell heating using high-resolution thermography. Shell pigmentation was quantified densitometrically. There were significant effects of both shell size and light wavelength, such that small snails heated more than large ones over 15 min, and blue light (470 nm) raised temperature more than green light (525 nm). Pigmentation alone did not show significance, but a trend towards higher temperature with increasing pigmentation was evident. Despite the observed significances and trends, we could only explain at most 4.67% of variation in shell heating by multiple regression modelling. However, the light intensity used in this experiment was low and the pigmentation intensity of the shells varied, at most, by a factor of 2. This suggests the actual temperature of a snail depends not only on the tested variables, but also on the multifactorial action of a number of unknown, perhaps intrinsic physiological parameters.

Author(s):  
Hyunsik Im ◽  
Atanu Jana ◽  
Vijaya Gopalan Sree ◽  
QIANKAI BA ◽  
Seong Chan Cho ◽  
...  

Lead-free, non-toxic transition metal-based phosphorescent organic–inorganic hybrid (OIH) compounds are promising for next-generation flat-panel displays and solid-state light-emitting devices. In the present study, we fabricate highly efficient phosphorescent green-light-emitting diodes...


2021 ◽  
Vol 118 (2) ◽  
pp. 021102
Author(s):  
Dong-Pyo Han ◽  
Ryoto Fujiki ◽  
Ryo Takahashi ◽  
Yusuke Ueshima ◽  
Shintaro Ueda ◽  
...  

Electronics ◽  
2021 ◽  
Vol 10 (11) ◽  
pp. 1291
Author(s):  
Giuseppe Schirripa Schirripa Spagnolo ◽  
Fabio Leccese

Nowadays, signal lights are made using light-emitting diode arrays (LEDs). These devices are extremely energy efficient and have a very long lifetime. Unfortunately, especially for yellow/amber LEDs, the intensity of the light is closely related to the junction temperature. This makes it difficult to design signal lights to be used in naval, road, railway, and aeronautical sectors, capable of fully respecting national and international regulations. Furthermore, the limitations prescribed by the standards must be respected in a wide range of temperature variations. In other words, in the signaling apparatuses, a system that varies the light intensity emitted according to the operating temperature is useful/necessary. In this paper, we propose a simple and effective solution. In order to adjust the intensity of the light emitted by the LEDs, we use an LED identical to those used to emit light as a temperature sensor. The proposed system was created and tested in the laboratory. As the same device as the ones to be controlled is used as the temperature sensor, the system is very stable and easy to set up.


1992 ◽  
Vol 283 ◽  
Author(s):  
Peter Steiner ◽  
Frank Kozlowski ◽  
Hermann Sandmaier ◽  
Walter Lang

ABSTRACTFirst results on light emitting diodes in porous silicon were reported in 1991. They showed a quantum efficiency of 10-7 to 10-5 and an orange spectrum. Over the last year some progress was achieved:- By applying UV-light during the etching blue and green light emitting diodes in porous silicon are fabricated.- When a p/n junction is realized within the porous region, a quantum efficiency of 10-4 is obtained.


2001 ◽  
Vol 34 (12) ◽  
pp. 4124-4129 ◽  
Author(s):  
Min Zheng ◽  
Liming Ding ◽  
E. Elif Gürel ◽  
Paul M. Lahti ◽  
Frank E. Karasz
Keyword(s):  

2010 ◽  
Vol 428-429 ◽  
pp. 421-425 ◽  
Author(s):  
Ye Tang Guo ◽  
Yuan Ming Huang

Well known long-persistent phosphorous strontium aluminates were synthesized by conventional combustion method in a furnace at about 600oC. By incorporating the obtained phosphorous strontium aluminates into organic host polystyrene, we prepared the organic-inorganic composite material (i.e., phosphor-polystyrene) which could be cast into flexible and green-light- emitting films. The morphology of the obtained phosphorous strontium aluminates and the phosphorescence of the organic-inorganic composite films were characterized with the scanning electron microscopy and the fluorescence spectroscopy, respectively. Our results show that the organic-inorganic composite films can be used as green-light- emitting roll-able screens in the industry of information displays.


1995 ◽  
Vol 187 (2) ◽  
pp. 467-470 ◽  
Author(s):  
W. C. Harsch ◽  
G. Cantwell ◽  
J. F. Schetzina

2000 ◽  
Vol 180 (1) ◽  
pp. 217-223 ◽  
Author(s):  
M.W. Cho ◽  
J.H. Chang ◽  
H. Wenisch ◽  
H. Makino ◽  
T. Yao

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