scholarly journals Global Annual Mean Atmospheric Histories, Growth Rates and Seawater Solubility Estimations of the Halogenated Compounds HCFC-22, HCFC-141b, HCFC-142b, HFC-134a, HFC-125, HFC-23, PFC-14 and PFC-116

2018 ◽  
Author(s):  
Pingyang Li ◽  
Jens Mühle ◽  
Stephen A. Montzka ◽  
David E. Oram ◽  
Benjamin R. Miller ◽  
...  
Keyword(s):  
Growth Rates ◽  
Water Solubility ◽  
Halogenated Compounds ◽  
Salting Out ◽  
East Anglia ◽  
Model Calculations ◽  
Linear Free Energy ◽  
Hfc 134A ◽  
The Future ◽  
Hcfc 142B

Abstract. We present consistent annual mean atmospheric histories and growth rates for the mainly anthropogenic halogenated compounds HCFC-22, HCFC-141b, HCFC-142b, HFC-134a, HFC-125, HFC-23, PFC-14 and PFC-116, all potentially useful oceanic transient tracers (tracers of water transport within the ocean), for the Northern and Southern Hemisphere with the aim of providing input histories for these compounds. Where available we utilize observations of the halogenated compounds made by the Advanced Global Atmospheric Gases Experiment (AGAGE), National Oceanic and Atmospheric Administration (NOAA) and University of East Anglia (UEA). Prior to the direct observational record we estimated the atmospheric history concentrations from other sources such as archived air measurements, firn air measurements and published model calculations. The results show that the atmospheric mole fractions for each species have been increasing since they were initially produced. Recently, their atmospheric growth rates are decreasing for HCFCs (HCFC-22, HCFC-141b and HCFC-142b), increasing for HFCs (HFC-134a, HFC-125, HFC-23), and stable with small fluctuation for PFCs (PFC-14 and PFC-116). The atmospheric histories (source functions) and natural background values show that HCFCs (HCFC-22, HCFC-141b and HCFC-142b) and HFCs (HFC-134a, HFC-125 and HFC-23) have the potential to be oceanic transient tracers for the next few decades only because of the recently imposed bans on production. When the atmospheric histories of the compounds are not monotonically changing, the equilibrium atmospheric concentrations (and ultimately the age associated with that concentration) calculated from their concentration in the ocean are not unique, reducing the potential as transient tracer. Moreover, HFCs have potential to be oceanic transient tracers for a longer period in the future than HCFCs as the growth rates of HFCs are increasing and those of HCFCs are decreasing in the background atmosphere. PFC-14 and PFC-116, however, have the potential to be the tracers for longer period in the future thanks to their extremely long lifetimes, steady atmospheric growth rates and no explicit ban. In this work, we also derive solubility functions for HCFC-22, HCFC-141b, HCFC-142b, HFC-134a, HFC-125, HFC-23, PFC-14 and PFC-116 in seawater to facilitate the use as oceanic transient tracers. These functions are based on the Clark-Glew-Weiss (CGW) water solubility functions fit and salting-out coefficients estimated by the poly-parameter linear free energy relationships (pp-LFERs). Here we also provide three methods of seawater solubility estimation for more compounds.

scholarly journals Atmospheric histories, growth rates and solubilities in seawater and other natural waters of the potential transient tracers HCFC-22, HCFC-141b, HCFC-142b, HFC-134a, HFC-125, HFC-23, PFC-14 and PFC-116

Ocean Science ◽  
2019 ◽  
Vol 15 (1) ◽  
pp. 33-60 ◽  
Author(s):  
Pingyang Li ◽  
Jens Mühle ◽  
Stephen A. Montzka ◽  
David E. Oram ◽  
Benjamin R. Miller ◽  
...  
Keyword(s):  
Mole Fraction ◽  
Growth Rates ◽  
Natural Waters ◽  
Water Solubility ◽  
Halogenated Compounds ◽  
Model Calculations ◽  
Hfc 134A ◽  
Wide Range ◽  
The Future ◽  
Hcfc 142B

Abstract. We present consistent annual mean atmospheric histories and growth rates for the mainly anthropogenic halogenated compounds HCFC-22, HCFC-141b, HCFC-142b, HFC-134a, HFC-125, HFC-23, PFC-14 and PFC-116, which are all potentially useful oceanic transient tracers (tracers of water transport within the ocean), for the Northern and Southern Hemisphere with the aim of providing input histories of these compounds for the equilibrium between the atmosphere and surface ocean. We use observations of these halogenated compounds made by the Advanced Global Atmospheric Gases Experiment (AGAGE), the Scripps Institution of Oceanography (SIO), the Commonwealth Scientific and Industrial Research Organization (CSIRO), the National Oceanic and Atmospheric Administration (NOAA) and the University of East Anglia (UEA). Prior to the direct observational record, we use archived air measurements, firn air measurements and published model calculations to estimate the atmospheric mole fraction histories. The results show that the atmospheric mole fractions for each species, except HCFC-141b and HCFC-142b, have been increasing since they were initially produced. Recently, the atmospheric growth rates have been decreasing for the HCFCs (HCFC-22, HCFC-141b and HCFC-142b), increasing for the HFCs (HFC-134a, HFC-125, HFC-23) and stable with little fluctuation for the PFCs (PFC-14 and PFC-116) investigated here. The atmospheric histories (source functions) and natural background mole fractions show that HCFC-22, HCFC-141b, HCFC-142b, HFC-134a, HFC-125 and HFC-23 have the potential to be oceanic transient tracers for the next few decades only because of the recently imposed bans on production and consumption. When the atmospheric histories of the compounds are not monotonically changing, the equilibrium atmospheric mole fraction (and ultimately the age associated with that mole fraction) calculated from their concentration in the ocean is not unique, reducing their potential as transient tracers. Moreover, HFCs have potential to be oceanic transient tracers for a longer period in the future than HCFCs as the growth rates of HFCs are increasing and those of HCFCs are decreasing in the background atmosphere. PFC-14 and PFC-116, however, have the potential to be tracers for longer periods into the future due to their extremely long lifetimes, steady atmospheric growth rates and no explicit ban on their emissions. In this work, we also derive solubility functions for HCFC-22, HCFC-141b, HCFC-142b, HFC-134a, HFC-125, HFC-23, PFC-14 and PFC-116 in water and seawater to facilitate their use as oceanic transient tracers. These functions are based on the Clark–Glew–Weiss (CGW) water solubility function fit and salting-out coefficients estimated by the poly-parameter linear free-energy relationships (pp-LFERs). Here we also provide three methods of seawater solubility estimation for more compounds. Even though our intention is for application in oceanic research, the work described in this paper is potentially useful for tracer studies in a wide range of natural waters, including freshwater and saline lakes, and, for the more stable compounds, groundwaters.

Agriculture of Russia: an Optimistic View of the Future

2020 ◽  
pp. 2-5
Author(s):  
A.F. Serkov ◽  
◽  
M.V. Kharina ◽  
V.S. Chekalin ◽  
◽  
...  
Keyword(s):  
National Economy ◽  
Growth Rates ◽  
Agricultural Policy ◽  
Agricultural Sector ◽  
Economic Relations ◽  
The Future

The article considers strategic directions of modern agricultural policy in Russia, outlines the problems of the development of the agricultural sector in conjunction with the functioning of the national economy. An attempt has been made to formulate the problems of the formation of socio-economic relations for a more distant prospect - the next 30 years. The possible growth rates of production in agriculture according to the optimistic and inertial options are determined.

scholarly journals Changing trends and emissions of hydrochlorofluorocarbons and their hydrofluorocarbon replacements

2016 ◽  
Author(s):  
Peter G. Simmonds ◽  
Matthew Rigby ◽  
Archibold McCulloch ◽  
Simon O'Doherty ◽  
Dickon Young ◽  
...  
Keyword(s):  
Growth Rates ◽  
Montreal Protocol ◽  
Hfc 134A ◽  
Production And Consumption ◽  
Ozone Depleting Substances ◽  
Phase Out ◽  
Article 5 ◽  
The Impact ◽  
Global Emissions

Abstract. High frequency, in situ global observations of HCFC-22 (CHClF2), HCFC-141b (CH3CCl2F), HCFC-142b (CH3CClF2) and HCFC-124 (CHClFCF3) and their main HFC replacements HFC-134a (CH2FCF3), HFC-125 (CHF2CF3), HFC-143a (CH3CF3), and HFC-32 (CH2F2) have been used to determine their changing global growth rates and emissions in response to the Montreal Protocol and its recent amendments. The 2007 adjustment to the Montreal Protocol required the accelerated phase-out of HCFCs with global production and consumption capped in 2013, to mitigate their environmental impact as both ozone depleting substances and important greenhouse gases. We find that this change has coincided with a reduction in global emissions of the four HCFCs with aggregated global emissions in 2015 of 444 ± 75 Gg/yr, in CO2 equivalent units (CO2 e) 0.75 ± 0.1 Gt/yr, compared with 483 ± 70 Gg/yr (0.82 ± 0.1 Gt/yr CO2 e) in 2010. (All quoted uncertainties in this paper are 1 sigma). About 80 % of the total HCFC atmospheric burden in 2015 is HCFC-22, where global HCFC emissions appear to have been relatively constant in spite of the 2013 cap on global production and consumption. We attribute this to a probable increase in production and consumption of HCFC-22 in Montreal Protocol Article 5 (developing) countries and the continuing release of HCFC-22 from the large banks which dominate HCFC global emissions. Conversely, the four HFCs all show increasing annual growth rates with aggregated global HFCs emissions in 2015 of 329 ± 70 Gg/yr (0.65 ± 0.12 Gt/yr CO2 e) compared to 2010 with 240 ± 50 Gg/yr (0.47 ± 0.08 Gt/yr CO2 e). As HCFCs are replaced by HFCs we investigate the impact of the shift to refrigerant blends which have lower global warming potentials (GWPs). We also note that emissions of HFC-125 and HFC-32 appear to have increased more rapidly during the 2011–2015 5-yr period compared to 2006–2010.

scholarly journals Suggested Procedures for the Reproducible Synthesis of Poly(d,l-lactideco-glycolide) Nanoparticles Using the Emulsification Solvent Diffusion Platform

2018 ◽  
Vol 14 (5) ◽  
pp. 448-453 ◽  
Author(s):  
Shadabul Haque ◽  
Ben J. Boyd ◽  
Michelle P. McIntosh ◽  
Colin W. Pouton ◽  
Lisa M. Kaminskas ◽  
...  
Keyword(s):  
Ethyl Acetate ◽  
Water Solubility ◽  
Plga Nanoparticles ◽  
Diffusion Method ◽  
Salting Out ◽  
Solvent Diffusion ◽  
Zeta Potentials ◽  
Highly Sensitive ◽  
Nanoparticulate Systems ◽  
Uniform Particle Size

Background: Poly(d,l-lactide-co-glycolide) (PLGA) based biodegradable nanoparticles are of key interest for the development of controlled release drug delivery systems and for other biomedical applications. It has been reported that PLGA polymers can be converted into colloidal nanoparticulate systems by various techniques, such as emulsification-diffusion, emulsificationevaporation, interfacial deposition, salting out, dialysis and nanoprecipitation. Emulsificationevaporation with water immiscible solvents including dichloromethane and chloroform has been the preferred method for the synthesis of PLGA nanoparticles due to the low boiling point and limited water solubility of these solvents. We and others, however, have found that when water-immiscible solvents are used for the synthesis of PLGA nanoparticles, particle aggregation, non-uniform particle size and multimodal size distribution are commonly encountered problems. This suggests that the synthesis of PLGA nanoparticles using water immiscible solvents is highly sensitive to small procedural variations that affect overall reproducibility. Objective: This study presents a simple and robust procedure for the preparation of PLGA nanoparticles with very small batch to batch variability (<5% variability in size (z-average) as determined by dynamic light scattering). Results: The results showed that the emulsification solvent diffusion method teamed with partially water-miscible solvents, such as ethyl acetate, is a versatile approach for the preparation of PLGA nanoparticles with highly reproducible sizes (between 50 and 400 nm) and zeta potentials (between - 30 and +30 mV), with relatively narrow polydispersity. Conclusion: Emulsification-diffusion with ethyl acetate is, therefore, a more reliable alternative to several existing procedures for the reproducible and refined synthesis of PLGA nanoparticles.

Rheological Behavior of Mixtures of Polystyrene with HCFC 142b and HFC 134a

1999 ◽  
Vol 35 (3) ◽  
pp. 221-246 ◽  
Author(s):  
Richard Gendron ◽  
Louis E. Daigneault ◽  
Louis Michel Caron
Keyword(s):  
Rheological Behavior ◽  
Hfc 134A ◽  
Hcfc 142B

scholarly journals A Framework to The Inventory of Cuture-based Tourism Products

2017 ◽  
Author(s):  
Cláudia Henriques ◽  
Manuela Guerreiro ◽  
Júlio Mendes
Keyword(s):  
Growth Rates ◽  
Cultural Tourism ◽  
Self Esteem ◽  
Market Segment ◽  
Employment Opportunities ◽  
The Future ◽  
World Tourism Organization ◽  
Tourism Destinations ◽  
To Come ◽  
Tourism Organization

Cultural Tourism is a promising market segment with higher growth rates than other niches. World Tourism Organization (UNWTO) data indicate that the proportion of international trips accounted for cultural motivations grew from 37% in 1995 to 40% in 2004. Additionally, UNWTO (2015) considers that this type of tourism could, in the future, increase competitiveness, create employment opportunities, generate income for investment in preservation, and simultaneously contribute to a sense of pride and self-esteem among host communities. In this article the authors propose a reflection on cultural tourism, based on the questioning of concepts such as tourism and culture, experiences and transformations. To this purpose, this paper aims to come up with a framework upon which tourism destinations can develop culture-based tourism products.

Synthesis of water-soluble conducting polypyrrole with transition-metal tetrasulfonated porphyrins

2010 ◽  
Vol 14 (02) ◽  
pp. 128-132 ◽  
Author(s):  
Mohammad Reza Nabid ◽  
Mitra Shamsianpour ◽  
Roya Sedghi ◽  
Samira Osati ◽  
Nasser Safari
Keyword(s):  
Transition Metal ◽  
Water Solubility ◽  
Water Soluble ◽  
Sulfonated Polystyrene ◽  
Salting Out ◽  
Electrically Conducting ◽  
Ph Values ◽  
Ft Ir ◽  
A Charge ◽  
Conducting Polypyrrole

A novel catalytic route for the synthesis of a water-soluble and electrically conducting polypyrrole (PPy) in the presence of sulfonated polystyrene (SPS) is presented. Anionic water-soluble transition-metal tetrasulfonated porphyrins (TSPP) were used to catalyze the polymerization. The reactions were carried out with different monomer, catalyst, template and initiator concentrations and the optimum conditions are reported. Also various pH values ranging from 1 to 4 were investigated. The absorbance of the polaron bands at different pH values demonstrates that pH 2 is the best condition for polymerization. Precipitation or "salting out" phenomenon was highly dependent on the mentioned factors. The formation of PPy was confirmed by UV-vis and FT-IR spectroscopy. Cyclic voltammetry (CV) showed that the synthesized polymer has convenient electroactivity. Furthermore, the presence of SPS that serves as a charge-compensating dopant in this complex provides a unique combination of properties such as processability and water solubility.

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