scholarly journals A simulation chamber for absorption spectroscopy in planetary atmospheres

2021 ◽  
Vol 14 (11) ◽  
pp. 7187-7197
Author(s):  
Marcel Snels ◽  
Stefania Stefani ◽  
Angelo Boccaccini ◽  
David Biondi ◽  
Giuseppe Piccioni
Keyword(s):  
Extrasolar Planets ◽  
Planetary Atmospheres ◽  
Absorption Bands ◽  
Continuum Absorption ◽  
Ambient Temperatures ◽  
Physical Conditions ◽  
Temperature And Pressure ◽  
Absorption Chamber ◽  
Simulation Chamber ◽  
Absorption Measurements

Abstract. A novel simulation chamber, PASSxS (Planetary Atmosphere Simulation System for Spectroscopy), has been developed for absorption measurements performed with a Fourier transform spectrometer (FTS) and, possibly, a cavity ring-down (CRD) spectrometer with a sample temperature ranging from 100 up to 550 K, while the pressure of the gas can be varied from 10 mbar up to 60 bar. These temperature and pressure ranges cover a significant part of the planetary atmospheres in the solar system, and the absorption chamber can thus be used to simulate planetary atmospheres of solar planets and extrasolar planets with similar physical conditions. The optical absorption path for the FTS absorption measurements is 3.2 m due to the implementation of a multi-pass setup inside the chamber. The FTS measurements cover a wide spectral range, from the visible to the mid-infrared, with a sensitivity sufficient for medium-strength absorption bands. The FTS has been used previously to measure high-pressure atmospheres, including collision-induced absorption bands and continuum absorption at ambient temperatures. PASSxS allows the measurement of the temperature dependence of collision-induced bands and continuum absorption, which is important for both the modeling of planetary atmospheres and fundamental processes involving collisions between molecules and atoms.

scholarly journals A simulation chamber for absorption spectroscopy in planetary atmospheres

2021 ◽  
Author(s):  
Marcel Snels ◽  
Stefania Stefani ◽  
Angelo Boccaccini ◽  
David Biondi ◽  
Giuseppe Piccioni
Keyword(s):  
Planetary Atmospheres ◽  
Fourier Transform Spectrometer ◽  
Absorption Bands ◽  
Continuum Absorption ◽  
Ambient Temperatures ◽  
Medium Strength ◽  
Temperature And Pressure ◽  
Absorption Chamber ◽  
Simulation Chamber ◽  
Absorption Measurements

Abstract. A novel simulation chamber PASSxS (Planetary Atmosphere Simulation System for Spectroscopy) has been developed for absorption measurements performed with a Fourier Transform Spectrometer (FTS) and, possibly, a cavity ring down (CRD) spectrometer, with a sample temperature ranging from 100 K up to 550 K, while the pressure of the gas can be varied from 10 mbar up to 60 bar. These temperature and pressure ranges cover a significant part of the planetary atmospheres in the solar system and the absorption chamber can thus be used to simulate planetary atmospheres of solar planets and extra solar planets with similar atmospheres. The optical absorption path for the FTS absorption measurements is 3.2 m, due to the implementation of a multipass setup inside the chamber. The FTS measurements cover a wide spectral range, from the visible to the mid-infrared with a sensitivity sufficient for medium strength absorption bands. The FTS has been used previously to measure high pressure atmospheres, including collision induced absorption bands and continuum absorption at ambient temperatures. PASSxS allows to measure the temperature dependence of collision induced bands and continuum absorption, which is important both for the modelling of planetary atmospheres as well as for fundamental processes involving collisions between molecules and atoms.

Composition Dependence of the Judd-Ofelt Intensity Parameters in TeO2-PbF2: Tm3+ Glasses

2004 ◽  
Vol 829 ◽  
Author(s):  
Idris Kabalci ◽  
Gonul Ozen ◽  
Adnan Kurt ◽  
Alphan Sennaroglu
Keyword(s):  
Cross Sections ◽  
Composition Dependence ◽  
Strong Dependence ◽  
Local Environment ◽  
Ground Level ◽  
Absorption Bands ◽  
Intensity Parameters ◽  
Nir Absorption ◽  
Doped Glasses ◽  
Absorption Measurements

ABSTRACTTm3+ -doped glasses with the composition of (1-x)TeO2-xPbF2, where x=10, 15, 20, 25 mol.% were synthesized and, their thermal and absorption measurements were investigated. All the glasses were transparent. The absorption bands corresponding to the absorption of the 1G4, 3F2, 3F3, 3F4, 3H5, and 3H4 levels from the 3H6 ground level of the Tm3+ ion were observed in the optical UV/VIS/NIR absorption measurements. We calculated the integrated absorption cross sections of each band except that of 3H5 level was found to vary with composition of the PbF2. The absorption measurements were first made to determine the spontaneous emission probabilities of the 4f-4f transitions of the Tm3+ ions. The calculations were made by using the Judd - Ofelt theory. The Ω2 parameter shows the strongest dependence on the host composition and it increases with the increasing PbF2 amount. The values Ω4 increases rather slowly while the value of Ω6 is practically independent of the composition. The strong dependence of the parameter Ω2 indicates that this parameter is related to the structural change and symmetry of the local environment of the Tm3+ ions in this glass.

scholarly journals Nanophotonics-enabled solar membrane distillation for off-grid water purification

2017 ◽  
Vol 114 (27) ◽  
pp. 6936-6941 ◽  
Author(s):  
Pratiksha D. Dongare ◽  
Alessandro Alabastri ◽  
Seth Pedersen ◽  
Katherine R. Zodrow ◽  
Nathaniel J. Hogan ◽  
...  
Keyword(s):  
Operating Temperature ◽  
Membrane Distillation ◽  
Operating Costs ◽  
Input Flow ◽  
Ambient Temperatures ◽  
Photothermal Heating ◽  
Promising Solution ◽  
Human Use ◽  
Temperature And Pressure ◽  
Desalination Plants

With more than a billion people lacking accessible drinking water, there is a critical need to convert nonpotable sources such as seawater to water suitable for human use. However, energy requirements of desalination plants account for half their operating costs, so alternative, lower energy approaches are equally critical. Membrane distillation (MD) has shown potential due to its low operating temperature and pressure requirements, but the requirement of heating the input water makes it energy intensive. Here, we demonstrate nanophotonics-enabled solar membrane distillation (NESMD), where highly localized photothermal heating induced by solar illumination alone drives the distillation process, entirely eliminating the requirement of heating the input water. Unlike MD, NESMD can be scaled to larger systems and shows increased efficiencies with decreased input flow velocities. Along with its increased efficiency at higher ambient temperatures, these properties all point to NESMD as a promising solution for household- or community-scale desalination.

scholarly journals Light absorption efficiencies of photosynthetic pigments: the dependence on spectral types of central stars

2014 ◽  
Vol 14 (3) ◽  
pp. 505-510 ◽  
Author(s):  
Yu Komatsu ◽  
Masayuki Umemura ◽  
Mitsuo Shoji ◽  
Megumi Kayanuma ◽  
Kazuhiro Yabana ◽  
...  
Keyword(s):  
Photosynthetic Pigments ◽  
Light Absorption ◽  
Extrasolar Planets ◽  
Soret Band ◽  
Absorption Bands ◽  
Radiation Spectra ◽  
Stellar Radiation ◽  
Higher Temperature ◽  
M Stars ◽  
Lower Temperature

AbstractFor detecting life from reflection spectra on extrasolar planets, trace of photosynthesis is one of the indicators. However, it is not yet clear what kind of radiation environments is acceptable for photosynthesis. Light absorption in photosystems on the Earth occurs using limited photosynthetic pigments such as chlorophylls (Chls) and bacteriochlorophylls (BChls). Efficiencies of light absorption for the pigments were evaluated by calculating the specific molecular absorption spectra at the high accuracy-quantum mechanical level. We used realistic stellar radiation spectra such as F, G, K and M-type stars to investigate the efficiencies. We found that the efficiencies are increased with the temperature of stars, from M to F star. Photosynthetic pigments have two types of absorption bands, the Qy and Soret. In higher temperature stars like F star, contributions from the Soret region of the pigments are dominant for the efficiency. On the other hand, in lower temperature stars like M stars, the Qy band is crucial. Therefore, differences on the absorption intensity and the wavelength between the Qy and Soret band are the most important to characterize the photosynthetic pigments. Among photosynthetic pigments, Chls tend to be efficient in higher temperature stars, while BChls are efficient for M stars. Blueward of the 4000 Å break, the efficiencies of BChls are smaller than Chls in the higher temperature stars.

Heat Flow Transducer Responses to Hyperbaric Environments

1980 ◽  
Vol 102 (3) ◽  
pp. 247-252 ◽  
Author(s):  
M. L. Nuckols
Keyword(s):  
Heat Flow ◽  
Ambient Pressure ◽  
Heat Fluxes ◽  
Constant Heat ◽  
Flow Transducer ◽  
Ambient Temperatures ◽  
Temperature And Pressure ◽  
Environmental Temperatures ◽  
Body Heat ◽  
Hyperbaric Conditions

The responses of heat flow transducers, used in the evaluation of convective body heat losses, have been investigated at hyperbaric environments. Environmental temperatures, pressures, and gas composition were varied while transducer responses to constant heat fluxes were observed. Ambient temperatures were varied between 3° and 40° C. Ambient pressures were varied between simulated depths of 0 and 1000 feet of seawater (445 psi). Transducer responses to heat fluxes varying between 0 and 250 watts/m2 are reported in the above temperature and pressure ranges within atmospheres of helium, nitrogen, and air. Ambient pressure variations were found to have little effect on the response of the heat flow transudcers to a constant heat source once appropriate temperature corrections were made. However, transducer response variations of up to 14 percent were observed when environmental gas compositions were varied at hyperbaric conditions.

scholarly journals In situ Investigations from Spinels under high pressure and high Temperatures

2014 ◽  
Vol 70 (a1) ◽  
pp. C398-C398
Author(s):  
Michael Wehber ◽  
Frank Schilling ◽  
Christian Lathe ◽  
Hans Mueller
Keyword(s):  
High Pressure ◽  
Volume Change ◽  
X Ray Diffraction ◽  
Ambient Temperatures ◽  
The Earth ◽  
Deep Interior ◽  
State Apparatus ◽  
Temperature And Pressure ◽  
Murnaghan Equation

Spinels seem to be important constituents of the deep interior of the Earth while transition with spinel or pseudospinel structure strongly influence the dynamic of the mantle. On the other hand, spinels are widely used as artificial material. The spinels Magnetite, Franklinite, and Gahnite are investigated at the Hamburger Synchrotron Laboratory (HASYLAB) at Hamburg. The experiments were carried out using the high pressure multi anvil devices MAX80 (F2.1 Beamline) and MAX200x (W2 Beamline). The MAX80 is a single state apparatus located at a bending magnet, MAX200x is a double state system located at a wiggler. Energy-dispersive X-ray diffraction in combination with Rietveld refinement [1, 2] was used to determine the pressure and temperature induced volume change. Isothermal experiments were performed up to 15 GPa at ambient temperature. The temperature and pressure dependent volume change were derived from compression experiments using MAX80 apparatus up to 5 GPa at temperatures of 298, 500, 700, 900 and 1100 K. Bulk moduli at ambient temperatures using a Birch-Murnaghan equation of state result in KT=184(7) GPa with K'=4.5(2) for Magnetite, KT =178(6) with K'=4.6(4) for Franklinite, and KT =204(9) with K'=4.9(6) for Gahnite.

scholarly journals MULTICHARME: A modified Chernin-type multi-pass cell designed for IR and THz long-path absorption measurements in the CHARME atmospheric simulation chamber

2021 ◽  
Author(s):  
Jean Decker ◽  
Éric Fertein ◽  
Jonas Bruckhuisen ◽  
Nicolas Houzel ◽  
Pierre Kulinski ◽  
...  
Keyword(s):  
Polar Compounds ◽  
Thz Spectroscopy ◽  
Near Ir ◽  
Atmospheric Reactivity ◽  
High Degree ◽  
First Time ◽  
Effective Reflectivity ◽  
Simulation Chamber ◽  
Absorption Measurements ◽  
Better Than

Abstract. We have developed MULTICHARME, a modified Chernin-type multi-pass cell especially designed for IR and THz long-path absorption measurements in the CHamber for Atmospheric Reactivity and Metrology of the Environment (CHARME). By measuring the output power using a near-IR diode-laser and a THz amplified multiplication chain, we have established that the effective reflectivity of MULTICHARME is better than 94 % over approximately three decades of frequency. Absorption measurements of N2O have been performed by probing highly excited rovibrational transitions in the near-IR and ground state rotational transitions at submillimetre wavelengths. In each case the linearity of the absorbance with the pathlengths was verified. Finally, we demonstrate that THz spectroscopy is able to study the isotopic composition of greenhouse polar gases such as N2O and to absolutely quantify stable (N2O) and reactive (O3) species at trace levels. Moreover, a THz monitoring at low pressure of the ozone decay in the chamber has been performed. The deduced ozone lifetime of 3.4 ± 0.1 h is shorter compared with previous measurements performed in CHARME at atmospheric pressure. For the first time, the ability of THz rotational spectroscopy to monitor, with a very high degree of selectivity, stable and reactive polar compounds at trace level in an atmospheric simulation chamber is demonstrated. However, the sensitivity of the THz monitoring needs to be improved to reach the atmospheric trace levels. For this purpose, it is necessary to figure out the baseline variations as well as possible induced by the multiple standing waves present in MULTICHARME.

scholarly journals A New Non-Centrosymmetricorganotin (IV) Hybrid Compound C5H14N2 [SnCl6] 2H2O: Crystal Structure And Optical Study Characterization

2021 ◽  
Author(s):  
Nejeh Hannachi ◽  
Thierry ROISNEL ◽  
Faouzi HLEL
Keyword(s):  
Crystal Structure ◽  
Single Crystal ◽  
Optical Band Gap ◽  
X Ray Diffraction ◽  
Absorption Bands ◽  
Hybrid Compound ◽  
Visible Absorption ◽  
X Ray ◽  
Uv Visible ◽  
Absorption Measurements

Abstract A new non-centrosymmetricorganotin (IV) hybrid compoundC5H14N2 [SnCl6] 2H2O was determined by single crystal X-ray diffraction at 150(2) K. Its crystal structure was solved by single crystal X-ray diffraction reveling that compound crystallizes in the orthorhombic system with Pbca space group with the following lattice parameters: a = 12.1486 (15) Å, b= 15.4571 (17) Å, c = 16.7610 (18) Å with Z = 8. The bonding between inorganic and organic entities in the compounds is realized by hydrogen bonding O−H…O ,O−H…Cl , NH • • • Cl, N-H…Cl and O−H…Cl. Finally,UV-visible absorption measurements exhibit two absorption bands (226 nm and 262 nm).The optical band gap (Eg) is deduced to be 3.46 Ev.

Subcritical and Supercritical Nanodroplet Evaporation: A Molecular Dynamics Investigation

2007 ◽  
Author(s):  
S. Mikkilineni ◽  
E. S. Landry ◽  
A. J. H. McGaughey
Keyword(s):  
Molecular Dynamics ◽  
Critical Temperature ◽  
Critical Pressure ◽  
Ambient Pressure ◽  
Transition Line ◽  
Ambient Temperatures ◽  
Lennard Jones ◽  
Temperature And Pressure ◽  
A New Technique ◽  
Dynamics Simulations

Molecular dynamics simulations are used to investigate the subcritical and supercritical evaporation of a Lennard-Jones (LJ) argon nanodroplet in its own vapor. Using a new technique to control both the ambient temperature and pressure, a range of conditions are considered to define a transition line between subcritical and supercritical evaporation. The evaporation is considered to be supercritical if the surface temperature of the droplet reaches the LJ argon critical temperature during its lifetime. Between ambient temperatures of 300 K and 800 K, the transition from subcritical to supercritical evaporation is observed to occur at an ambient pressure 1.4 times greater than the LJ argon critical pressure. For subcritical conditions, the droplet lifetimes obtained from the simulations are compared to independently predicted lifetimes from the D2 law.

scholarly journals Retrieval of temperature and pressure using broadband solar occultation: SOFIE approach and results

2011 ◽  
Vol 4 (5) ◽  
pp. 893-907 ◽  
Author(s):  
B. T. Marshall ◽  
L. E. Deaver ◽  
R. E. Thompson ◽  
L. L. Gordley ◽  
M. J. McHugh ◽  
...  
Keyword(s):  
Measurement Technique ◽  
Atmospheric Temperature ◽  
Co2 Absorption ◽  
Gas Mixing ◽  
Absorption Bands ◽  
Atmospheric Processes ◽  
Mixing Ratios ◽  
Solar Occultation ◽  
Sensitivity Studies ◽  
Temperature And Pressure

Abstract. Measurement of atmospheric temperature as a function of pressure, T(P), is key to understanding many atmospheric processes and a prerequisite for retrieving gas mixing ratios and other parameters from solar occultation measurements. This paper gives a brief overview of the solar occultation measurement technique followed by a detailed discussion of the mechanisms that make the measurement sensitive to temperature. Methods for retrieving T(P) using both broadband transmittance and refraction are discussed. Investigations using measurements of broadband transmittance in two CO2 absorption bands (the 4.3 and 2.7 μm bands) and refractive bending are then presented. These investigations include sensitivity studies, simulated retrieval studies, and examples from SOFIE.

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