scholarly journals Photometric Observations of Aerosol Optical Properties and Emission Flux Rates of Stromboli Volcano Plume during the PEACETIME Campaign

2021 ◽  
Vol 13 (19) ◽  
pp. 4016
Author(s):  
Pasquale Sellitto ◽  
Giuseppe Salerno ◽  
Jean-François Doussin ◽  
Sylvain Triquet ◽  
François Dulac ◽  
...  
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Visible Range ◽  
Infrared Range ◽  
Emission Flux ◽  
Stromboli Volcano ◽  
Aerosol Emission ◽  
Photometric Observations ◽  
Sulphate Aerosols ◽  
Aerosol Emissions

The characterisation of aerosol emissions from volcanoes is a crucial step towards the assessment of their importance for regional air quality and regional-to-global climate. In this paper we present, for the first time, the characterisation of aerosol emissions of the Stromboli volcano, in terms of their optical properties and emission flux rates, carried out during the PEACETIME oceanographic campaign. Using sun-photometric observations realised during a near-ideal full plume crossing, a plume-isolated aerosol optical depth of 0.07–0.08 in the shorter-wavelength visible range, decreasing to about 0.02 in the near infrared range, was found. An Ångström exponent of 1.40 ± 0.40 was also derived. This value may suggest the dominant presence of sulphate aerosols with a minor presence of ash. During the crossing, two separate plume sections were identified, one possibly slightly affected by ash coming from a mild explosion, and the other more likely composed of pure sulphate aerosols. Exploiting the full crossing scan of the plume, an aerosol emission flux rate of 9–13 kg/s was estimated. This value was 50% larger than for typical passively degassing volcanoes, thus pointing to the importance of mild explosions for aerosol emissions in the atmosphere.

scholarly journals Combination of Zinc Oxide and Antimony Doped Tin Oxide Nanocoatings for Glazing Application

Coatings ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 248 ◽  
Author(s):  
Benjamin Schumm ◽  
Thomas Abendroth ◽  
Saleh A. Alajlan ◽  
Ahmed M. Almogbel ◽  
Holger Althues ◽  
...  
Keyword(s):  
Thin Films ◽  
Zinc Oxide ◽  
Optical Properties ◽  
Tin Oxide ◽  
Near Infrared ◽  
Glass Production ◽  
Float Glass ◽  
Building Envelope ◽  
Visible Range ◽  
Production Processes

Multilayered nanocoatings allow outstanding properties with broad potential for glazing applications. Here, we report on the development of a multilayer nanocoating for zinc oxide (ZnO) and antimony doped tin oxide (ATO). The combination of ZnO and ATO thin films with their promising optical properties is a cost-efficient alternative for the production of energy-efficient glazing. It is an effective modification of the building envelope to reduce current high domestic demand of electrical power for air conditioning, especially in hot climates like Saudi Arabia. In this paper, we report the development of a nanocoating based on the combination of ZnO and ATO. Principle material and film investigations were carried out on lab-scale by dip coating with chemical solution deposition (CSD), while with regard to production processes, chemical vapor deposition (CVD) processes were evaluated in a second stage of the film development. It was found that with both processes, high-quality thin films and multilayer coatings with outstanding optical properties can be prepared. While keeping the optical transmission in the visible range at around 80%, only 10% of the NIR (near infrared) and below 1% of UV (ultraviolet) light passes these coatings. However, in contrast to CSD, the CVD process allows a free combination of the multilayer film sequence, which is of high relevance for production processes. Furthermore, it can be potentially integrated in float glass production lines.

scholarly journals Optical investigation of bovine grey and white matters in visible and near-infrared ranges

2021 ◽  
Vol 27 (1) ◽  
pp. 99-107
Author(s):  
Ali Shahin ◽  
Wesam Bachir ◽  
Moustafa Sayem El-Daher
Keyword(s):  
Optical Properties ◽  
Absorption Coefficient ◽  
Wavelength Range ◽  
Grey Matter ◽  
Near Infrared ◽  
Biological Tissues ◽  
Integrating Sphere ◽  
Visible Range ◽  
Optical Investigation

Abstract Introduction: Due to enormous interests for laser in medicine and biology, optical properties characterization of different tissue have be affecting in development processes. In addition, the optical properties of biological tissues could be influenced by storage methods. Thus, optical properties of bovine white and grey tissues preserved by formalin have been characterized over a wide wavelength spectrum varied between 440 nm and 1000 nm. Materials and Methods: To that end, a single integrating sphere system was assembled for spectroscopic characterization and an inverse adding-doubling algorithm was used to retrieve optical coefficients, i.e. reduced scattering and absorption coefficients. Results: White matter has shown a strong scattering property in comparison to grey matter. On the other hand, the grey matter has absorbed light extensively. In comparison, the reduced scattering profile for both tissue types turned out to be consistent with prior works that characterized optical coefficients in vivo. On the contrary, absorption coefficient behavior has a different feature. Conclusion: Formalin could change the tissue’s optical properties because of the alteration of tissue’s structure and components. The absence of hemoglobin that seeps out due to the use of a formalin could reduce the absorption coefficient over the visible range. Both the water replacement by formalin could reduce the refractive index of a stored tissue and the absence of hemoglobin that scatters light over the presented wavelength range should diminish the reduced scattering coefficients over that wavelength range.

scholarly journals Methodological Basis of The UAVs Use for the Weed Detection

2018 ◽  
Keyword(s):  
Electromagnetic Waves ◽  
Near Infrared ◽  
Classification Method ◽  
Likelihood Method ◽  
Cultivated Plants ◽  
Visible Range ◽  
Infrared Range ◽  
Weed Detection ◽  
Weight Method ◽  
Remote Observation

Purpose. To work out methodological approaches to the use of quadcopters for weeds assesment. Methods. The shooting was carried out using DJI Phantom Vision 2+ and LadyBug Copper Dot. The LadyBug was shoted in the visible and near-infrared range using the 12-megapixel S100 NDVI UAV-Kit camera with elevations: 20 m, 40 m and 60 m. The DJI Phantom Vision 2+ was shot in the visible range of the GoPro 14 megapixel camera altitudes: 10 m, 15 m, 30 m and 60 m. Decryption of photographs was carried out using the controlled classification method in QGIS and TNTmips programs. Weed accounting was performed on control sites 1m2 by weight method, taking into account their qualitative composition. Results. It is shown that the best results of weed recognition during decoding of images was obtained by the use of controlled classification according to the maximum likelihood method under conditions of shooting from heights up to 40 m. In order to improve the recognition of weeds and separate their image from images of cultivated plants, it is expedient to use the object-oriented analysis. At the stage of sunflower budding, about 30% of the weeds are closed from the remote observation, which led to an automatic underestimation of number of weeds. Conclusions. In order to evaluate the crop contamination, it is possible to successfully use the data from UAVs in a visible range of electromagnetic waves under low altitudes (up to 40 meters) and the use of a controlled classification method for decoding images. For the recognition of weeds, the images in the infrared range do not have advantages over images in the visible range. It is necessary to additionally apply ground-based control of weeds to assess the proportion of "hidden" from remote observation of weeds.

scholarly journals Astaxanthin as a new Raman probe for biosensing of specific subcellular lipidic structures: can we detect lipids in cells under resonance conditions?

2020 ◽  
Author(s):  
Krzysztof Czamara ◽  
Adriana Adamczyk ◽  
Marta Stojak ◽  
Basseem Radwan ◽  
Malgorzata Baranska
Keyword(s):  
Near Infrared ◽  
Resonance Excitation ◽  
Live Cells ◽  
Visible Range ◽  
Infrared Range ◽  
Dependent Manner ◽  
Chromophore Group ◽  
Group A ◽  
Raman Probe ◽  
Near Infrared Range

AbstractHere we report a new Raman probe for cellular studies on lipids detection and distribution. It is (3S, 3'S)-astaxanthin (AXT), a natural xanthophyll of hydrophobic properties and high solubility in lipids. It contains a chromophore group, a long polyene chain of eleven conjugated C=C bonds including two in the terminal rings, absorbing light in the visible range that coincides with the excitation of lasers commonly used in Raman spectroscopy for studying of biological samples. Depending on the laser, resonance (excitation in the visible range) or pre-resonance (the near infrared range) Raman spectrum of astaxanthin is dominated by bands at ca. 1008, 1158, and 1520 cm−1 that now can be also a marker of lipids distribution in the cells. We showed that AXT accumulates in lipidic structures of endothelial cells in time-dependent manner that provides possibility to visualize e.g. endoplasmic reticulum, as well as nuclear envelope. As a non-toxic reporter, it has a potential in the future studies on e.g. nucleus membranes damage in live cells in a very short measuring time.

Progress in design, nanofabrication and performance of metalenses

2021 ◽  
Author(s):  
Zhenghao WANG ◽  
Yongling WU ◽  
Dongfeng QI ◽  
Wenhui YU ◽  
Hongyu ZHENG
Keyword(s):  
High Resolution ◽  
Near Infrared ◽  
Visible Range ◽  
Infrared Range ◽  
High Dispersion ◽  
High Resolution Imaging ◽  
Direct Writing ◽  
Nanoscale Structures ◽  
Resolution Imaging ◽  
And Performance

Abstract Metalens has been shown to overcome the diffraction limit of conventional optical lenses to achieve sub-wavelength resolution. Due to its planar structure and lightweight, metalens has the potential applications in the manufacture of flat lenses for cameras and other high resolution imaging optics. However, currently reported metalenses have low focusing efficiencies: 26% - 68% in THz and GHz range, 1% - 91% in near infrared range (NIR), and 5% - 91.6% in the visible range. Far field imaging in the visible light is essential for use in camera and mobile phones, which requires a complex metalens structure with multi-layers of alternating metal and dielectric layers. Most of the reported metalenses work in a single wavelength, mainly due to the high dispersion characteristics of the diffractive metalenses. It remains a challenge to realize high resolution imaging for a wide wavelength band in particular in the visible range. In this review, we report the state-of-the-art in metalens design principle, types of nanoscale structures, and various fabrication processes. We introduce femtosecond laser direct writing based on two-photon polymerization as an emerging nanofabrication technology. We provide an overview of the optical performance of the recently-reported metalenses and elaborate the major research and engineering challenges and future prospects.

Changes in Optical Properties of in vitro Myocardium Tissue Due to Heating in the Visible and Near-Infrared Range

2008 ◽  
Vol 35 (5) ◽  
pp. 792-796 ◽  
Author(s):  
敖荟兰 Ao Huilan ◽  
邢达 Xing Da ◽  
魏华江 Wei Huajiang ◽  
巫国勇 Wu Guoyong ◽  
鲁建军 Lu Jianjun
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Infrared Range ◽  
Near Infrared Range

Optical properties of a polyimide-fullerene system in the near infrared range (λ=1047 nm)

2003 ◽  
Vol 29 (8) ◽  
pp. 672-675 ◽  
Author(s):  
N. V. Kamanina ◽  
M. O. Iskandarov ◽  
A. A. Nikitichev
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Infrared Range ◽  
Near Infrared Range

Optical properties of bread in the near-infrared range

1988 ◽  
Vol 8 (2) ◽  
pp. 129-139 ◽  
Author(s):  
Christina Skjöldebrand ◽  
Christina Ellbjär ◽  
Claes Göran Andersson ◽  
Tord S. Eriksson
Keyword(s):  
Optical Properties ◽  
Near Infrared ◽  
Infrared Range ◽  
Near Infrared Range

scholarly journals Ga-Doped ZnO Coating—A Suitable Tool for Tuning the Electrode Properties in the Solar Cells with CdS/ZnS Core-Shell Quantum Dots

Crystals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 137
Author(s):  
Mariya Aleksandrova ◽  
Tatyana Ivanova ◽  
Velichka Strijkova ◽  
Tsvetozar Tsanev ◽  
Ajaya Kumar Singh ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Quantum Dots ◽  
Solar Cells ◽  
Indium Tin Oxide ◽  
Near Infrared ◽  
Optical Transmittance ◽  
Visible Range ◽  
Infrared Range ◽  
Layer System ◽  
Doped Zno

Two layer system from sputtered indium tin oxide (ITO) and gallium doped zinc oxide (Ga:ZnO, GZO) were studied for transparency in the visible electromagnetic range, reflectivity in the near infrared range, conductivity and valent band for a solar cells with quantum dots. The bi-layer coatings produced at optimized oxygen partial pressure, films thickness and surface roughness exhibit improved optical properties without worsening the electrical parameters, even if additional oxygen introduction during the reactive sputtering of the GZO. With an average optical transmittance of 91.3% in the visible range, average reflection and resistivity lower than 0.4 × 10−2 Ω.cm, these coatings are suitable for top electrode in the solar cells. The obtained results reveal that multilayered stacks of transparent ITO/Ga-doped ZnO coatings possess relatively low surface roughness (7–9 nm) and appropriate refractive index. The additional oxidation of GZO films induces modification of the film thickness and respectively of their optical performances.

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