Revised UV absorption spectra, ozone depletion potentials, and global warming potentials for the ozone-depleting substances CF2Br2, CF2ClBr, and CF2BrCF2Br

2013 ◽  
Vol 40 (2) ◽  
pp. 464-469 ◽  
Author(s):  
Dimitrios K. Papanastasiou ◽  
Nabilah Rontu Carlon ◽  
J. Andrew Neuman ◽  
Eric L. Fleming ◽  
Charles H. Jackman ◽  
...  
Keyword(s):  
Global Warming ◽  
Absorption Spectra ◽  
Ozone Depletion ◽  
Uv Absorption ◽  
Uv Absorption Spectra ◽  
Global Warming Potentials ◽  
Ozone Depleting Substances

scholarly journals UV and Infrared Absorption Spectra, Atmospheric Lifetimes, and Ozone Depletion and Global Warming Potentials for CCl2FCCl2F (CFC-112), CCl3CClF2 (CFC-112a), CCl3CF3 (CFC-113a), and CCl2FCF3 (CFC-114a)

2016 ◽  
Author(s):  
Maxine E. Davis ◽  
François Bernard ◽  
Max R. McGillen ◽  
Eric L. Fleming ◽  
James B. Burkholder
Keyword(s):  
Global Warming ◽  
Absorption Spectra ◽  
Infrared Absorption ◽  
Ozone Depletion ◽  
Stratospheric Ozone ◽  
Uv Absorption ◽  
Model Calculations ◽  
Uv Absorption Spectra ◽  
Infrared Absorption Spectra ◽  
Global Warming Potentials

Abstract. The potential impact of the recently observed CCl2FCCl2F (CFC-112), CCl3CClF2 (CFC-112a), CCl3CF3 (CFC-113a), and CCl2FCF3 (CFC-114a) (chlorofluorocarbons, CFCs), on stratospheric ozone and climate are presently not well characterized. In this study, the UV absorption spectra of these CFCs were measured between 192.5–235 nm over the temperature range 207–323 K. Precise parameterizations of the UV absorption spectra are presented. A 2-D atmospheric model was used to evaluate the CFC atmospheric loss processes, lifetimes, ozone depletion potentials (ODPs), and the associated uncertainty ranges in these metrics. The CFCs are primarily removed in the stratosphere by short wavelength UV photolysis with calculated global annually averaged steady-state lifetimes (years) of 63.6 (61.9–64.7), 51.5 (50.0–52.6), 55.4 (54.3–56.3), and 105.3 (102.9–107.4) for CFC-112, CFC-112a, CFC-113a, and CFC-114a, respectively. The range of lifetimes given in parentheses where obtained by including the 2σ uncertainty in the UV absorption spectra and O(1D) rate coefficients in the model calculations. The 2-D model was also used to calculate the CFC ozone depletion potentials (ODPs) with values of 0.98, 0.86, 0.73, and 0.72 obtained for CFC-112, CFC-112a, CFC-113a, and CFC-114a, respectively. Using the infrared absorption spectra and lifetimes determined in this work, the CFCs global warming potentials (GWPs) were estimated to be 4260 (CFC-112), 3330 (CFC-112a), 3650 (CFC-113a), and 6510 (CFC-114a) for the 100-year time-horizon.

scholarly journals UV and infrared absorption spectra, atmospheric lifetimes, and ozone depletion and global warming potentials for CCl<sub>2</sub>FCCl<sub>2</sub>F (CFC-112), CCl<sub>3</sub>CClF<sub>2</sub> (CFC-112a), CCl<sub>3</sub>CF<sub>3</sub> (CFC-113a), and CCl<sub>2</sub>FCF<sub>3</sub> (CFC-114a)

2016 ◽  
Vol 16 (12) ◽  
pp. 8043-8052 ◽  
Author(s):  
Maxine E. Davis ◽  
François Bernard ◽  
Max R. McGillen ◽  
Eric L. Fleming ◽  
James B. Burkholder
Keyword(s):  
Global Warming ◽  
Absorption Spectra ◽  
Infrared Absorption ◽  
Ozone Depletion ◽  
Stratospheric Ozone ◽  
Uv Absorption ◽  
Model Calculations ◽  
Uv Absorption Spectra ◽  
Infrared Absorption Spectra ◽  
Global Warming Potentials

Abstract. The potential impact of CCl2FCF3 (CFC-114a) and the recently observed CCl2FCCl2F (CFC-112), CCl3CClF2 (CFC-112a), and CCl3CF3 (CFC-113a) chlorofluorocarbons (CFCs) on stratospheric ozone and climate is presently not well characterized. In this study, the UV absorption spectra of these CFCs were measured between 192.5 and 235 nm over the temperature range 207–323 K. Precise parameterizations of the UV absorption spectra are presented. A 2-D atmospheric model was used to evaluate the CFC atmospheric loss processes, lifetimes, ozone depletion potentials (ODPs), and the associated uncertainty ranges in these metrics due to the kinetic and photochemical uncertainty. The CFCs are primarily removed in the stratosphere by short-wavelength UV photolysis with calculated global annually averaged steady-state lifetimes (years) of 63.6 (61.9–64.7), 51.5 (50.0–52.6), 55.4 (54.3–56.3), and 105.3 (102.9–107.4) for CFC-112, CFC-112a, CFC-113a, and CFC-114a, respectively. The range of lifetimes given in parentheses is due to the 2σ uncertainty in the UV absorption spectra and O(1D) rate coefficients included in the model calculations. The 2-D model was also used to calculate the CFC ozone depletion potentials (ODPs) with values of 0.98, 0.86, 0.73, and 0.72 obtained for CFC-112, CFC-112a, CFC-113a, and CFC-114a, respectively. Using the infrared absorption spectra and lifetimes determined in this work, the CFC global warming potentials (GWPs) were estimated to be 4260 (CFC-112), 3330 (CFC-112a), 3650 (CFC-113a), and 6510 (CFC-114a) for the 100-year time horizon.

Simulation of UV Absorption Spectra and Relaxation Dynamics of Uracil and Uracil-Water Clusters

2020 ◽  
Author(s):  
Branislav Milovanović ◽  
Jurica Novak ◽  
Mihajlo Etinski ◽  
Wolfgang Domcke ◽  
Nadja Doslic
Keyword(s):  
Aqueous Solution ◽  
Gas Phase ◽  
Absorption Spectra ◽  
Absorption Spectroscopy ◽  
Water Clusters ◽  
Uv Absorption ◽  
Relaxation Dynamics ◽  
Nonradiative Relaxation ◽  
Uv Absorption Spectra ◽  
Uv Absorption Spectroscopy

Despite many studies, the mechanisms of nonradiative relaxation of uracil in the gas phase and in aqueous solution are still not fully resolved. Here we combine theoretical UV absorption spectroscopy...

scholarly journals Subcritical and Supercritical Operation of Innovative Thermal Mechanical Refrigeration System

2020 ◽  
Author(s):  
Ahmad Sleiti ◽  
Wahib Al-Ammari ◽  
Mohammed Al-Khawaja ◽  
Maxim Glushenkov ◽  
Alexander Kronberg
Keyword(s):  
Global Warming ◽  
Ozone Depletion ◽  
Fossil Fuels ◽  
Waste Heat ◽  
Low Frequency ◽  
Low Grade ◽  
Refrigeration System ◽  
Heat System ◽  
Global Warming Potentials ◽  
Carbon Dioxide Co2

Around 17% of the globally generated energy is consumed for residential, commercial, and transportation refrigeration. The current cooling technologies utilize refrigerants with high Ozone Depletion and Global Warming Potentials. Furthermore, the current technologies are expensive alongside with toxicity and flammability hazards. On the other side, energy produced by combustion of fossil fuels results in substantial amounts of waste heat. Therefore, it is necessary to develop new refrigeration technologies that utilize waste heat as a source of energy with ecofriendly refrigerants with zero ozone depletion potential and zero global warming potential. In addition, this thermal mechanical refrigeration (TMR) technology improves the energy efficiency of the source of waste heat system and minimizes the emissions of the carbon dioxide (CO2). In this study, a novel thermo-mechanical refrigeration system is proposed. It operates with low-grade energy sources (such as waste heat) at temperature range of 60 oC to 100 oC. Furthermore, it has the advantage of working with low-frequency driver-compressor unit, which eliminates noise and increases its lifetime. Moreover, the TMR system is adaptable to commercial, transportation, and residential refrigeration applications.

scholarly journals UV-Absorption Spectra of Complexes Between Some Disulfides and Iodine. I.

1969 ◽  
Vol 23 ◽  
pp. 2127-2135 ◽  
Author(s):  
Bengt Nelander ◽  
G. Hagen ◽  
Seija Vesala ◽  
Tarja Aalto ◽  
Per-Erik Werner ◽  
...  
Keyword(s):  
Absorption Spectra ◽  
Uv Absorption ◽  
Uv Absorption Spectra

UV and IR Spectral Characteristics of Chloramben in Selected Environments

Weed Science ◽  
1976 ◽  
Vol 24 (1) ◽  
pp. 107-114 ◽  
Author(s):  
V. E. Berkheiser ◽  
J. L. Ahlrichs
Keyword(s):  
Ir Spectra ◽  
Water Content ◽  
Absorption Spectra ◽  
Spectral Characteristics ◽  
Uv Absorption ◽  
Hydration Water ◽  
Carboxyl Group ◽  
Amino Group ◽  
Acid Base ◽  
Uv Absorption Spectra

Ultraviolet (UV) absorption spectra were recorded of chloramben (3-amino-2,5-dichlorobenzoic acid) and selected relatives in solutions of different pH's. From these spectra, the Broensted acid-base properties of chloramben were deduced. Interpretations of solution spectra were applied to UV absorption spectra of chloramben adsorbed onto Ca-montmorillonite at low water content. Infrared (IR) transmittance spectra were recorded of chloramben and selected derivatives in KBr pellets and band assignments were made. Interpretations of these spectra were also applied to IR spectra of chloramben adsorbed onto Ca-montmorillonite at low water content. Both UV and IR measurements indicated that protonation of the amino group occurs and that the carboxyl group of chloramben is strongly hydrogen-bonded to the hydration water of the interlayer cations.

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