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Global air quality and climate change
Published in John K. Pearson, Richard G. Derwent, Air Pollution and Climate Change, 2022
John K. Pearson, Richard G. Derwent
Halocarbons are a group of up to forty organic compounds containing fluorine, chlorine, bromine or iodine that are widely used as aerosol propellants, refrigerants, air conditioning fluids, foam-blowing agents, anaesthetic gases and solvents. Each has its own emission pattern, atmospheric lifetime and radiative efficiency and hence ability to act as a greenhouse gas. Almost all, with a few notable exceptions, are entirely synthetic and are not present in nature and have only been present in the atmosphere in detectable levels since 1950.
Climate Change and its Impact on Plant–Microbe Interaction
Published in Javid A. Parray, Suhaib A. Bandh, Nowsheen Shameem, Climate Change and Microbes, 2022
Ozone is a greenhouse emission that is frequently made and destroyed within the atmosphere by chemical reactions. Within the layer, anthropogenic activities have raised gas through the discharge of gases like carbon monoxide, hydrocarbons, and nitrogen oxide that reacts with chemicals to provide gas. As mentioned earlier, halocarbons released by human activities destroy ozone in the stratosphere and have caused the ozone hole over Antarctica (Gupta et al., 2014).
Environment
Published in Suzanne K. Kearns, Fundamentals of International Aviation, 2021
Above the tropopause, the temperature increases throughout the stratosphere as a result of the ozone layer. Ozone, a very rare molecule in our atmosphere, plays an important role by filtering ultraviolet light and allowing only a limited amount to reach Earth’s surface. Unfortunately, human-produced chemicals (including halocarbons and chlorofluorocarbons [CFCs]) have a depleting impact on the ozone layer and are a significant environmental and health concern.
Rheology Properties of Cyclopentane Hydrate Slurry in the Presence of Wax Crystals
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2023
Jiaqiang Jing, Lequan Zhuang, Rinat Karimov, Jie Sun, Xingtang Zhang, Hang Yang
Materials included CP (Aladdin, 96% purity), 3# industrial white oil (Orncbio Lubricant Company, Shanghai), Halocarbon oil 27 (polychlorotrifluoroethylene polymer, Merck), deionized water, 58# paraffin wax (Sichuan Petroleum Branch Company, Chengdu), and sorbitan monooleate (Span 80, Aladdin). In this investigation, the oil phase of emulsions is composed of 50 vol% CP and the remainder 3# industrial white oil and Halocarbon oil 27. The density and viscosity of Halocarbon oil 27 are 1900 kg/m3 and 30 mPa·s at 20°C, respectively. Halocarbon oil 27 is used to match the densities of the oil and water phases to reduce the effects of droplet settling. The density and viscosity of 3# industrial white oil are 852 kg/m3 and 51 mPa·s at 20°C, respectively. The carbon distribution of 3# industrial white oil and 58# paraffin wax are shown in Tables 1 and 2, respectively. The thermal characteristics parameters of the wax precipitation of different wax content are shown in Table 3. Span 80 is a hydrophilic-lipophilic balanced nonionic surfactant utilized to form stable oil-water emulsions (Schmitt et al. 2017). Dosages of wax and Span 80 were determined with the mass fraction of oil. All factors were controlled constant in the hydrate formation experiments except water cut, wax content, and target temperature, including the dosage of Span 80 (0.5 wt%), shear rate (300 s−1), and cooling velocity (1°C/min).