Gas and water vapor transport through a series of novel poly(aryl ether sulfone) membranes

The permeation behavior of water vapor, H-2, CO2, O-2, N-2, and CH4 gases in a series of novel poly(aryl ether sulfone)s has been examined over a temperature range of 30-100 degreesC. These polymers include four alkyl-substituted cardo poly(aryl ether sulfone)s and four intermolecular interaction enhanced poly(aryl ether sulfone)s. Their water vapor and gas transport properties were compared to the unmodified cardo poly(aryl ether sulfone) (PES-C). It was found that the bulky alkyl substituents on the phenylene rings were advantageous for gas permeability, while the intermolecular hydrogen bonds and ionic bonds resulted in a considerable increase in gas permselectivity. The causes of the trend were interpreted according to free volume, interchain distance, and glass transition temperature, together with the respective contribution of gas solubility and diffusivity to the overall permeability. Of interest was the observation that IMPES-L, which simultaneously bears bulky isopropyl substituent and pendant carboxylic groups, displayed 377% higher O-2 permeability and 5.3% higher O-2/N-2 permselectivity than PES-C. Furthermore, sodium salt form PES-Na+ and potassium salt form PES-K+ exhibited water vapor permeability twice as high as PES-C and H2O/N-2 selectivity in 10(5) order of magnitude.

Is there a connection between high transport of water through the Rockall Trough and ecological changes in the North Sea?

Changes in the ecosystem of the North Sea may occur as pronounced inter-annual and step-wise shifts as well as gradual trends. Marked inter-annual shifts have occurred at least twice in the last two decades, the late 1980s and the late 1990s, that appear to reflect an increased inflow of oceanic water and species. Numerical modelling has demonstrated a link between altered rates of inflow of oceanic water into the northern North Sea and a regime shift after 1988. In 1989 and 1997 oceanic species not normally found in the North Sea were observed there, suggesting pulses of oceanic water had entered the basin and triggered the subsequent ecosystem change. The oceanic water has origins mainly west of Britain in the Rockall Trough, where the long-term mean volume transport is around 3.7Sv northwards (1Sv=10 super(6)m super(3)s super(1)), but in early 1989 and early 1998 was observed to be more than twice the mean value, reaching over 7Sv. These periods of high transport coinciding with the inferred pulses of oceanic water into the North Sea suggest a connection through the continental shelf edge current. Copyright 2001 International Council for the Exploration of the Sea

Localization of deep water formation: role of atmospheric moisture transport and geometrical constraints on ocean circulation

A series of coupled atmosphere–ocean–ice aquaplanet experiments is described in which topological constraints on ocean circulation are introduced to study the role of ocean circulation on the mean climate of the coupled system. It is imagined that the earth is completely covered by an ocean of uniform depth except for the presence or absence of narrow barriers that extend from the bottom of the ocean to the sea surface. The following four configurations are described: Aqua (no land), Ridge (one barrier extends from pole to pole), Drake (one barrier extends from the North Pole to 35°S), and DDrake (two such barriers are set 90° apart and join at the North Pole, separating the ocean into a large basin and a small basin, connected to the south). On moving from Aqua to Ridge to Drake to DDrake, the energy transports in the equilibrium solutions become increasingly “realistic,” culminating in DDrake, which has an uncanny resemblance to the present climate. Remarkably, the zonal-average climates of Drake and DDrake are strikingly similar, exhibiting almost identical heat and freshwater transports, and meridional overturning circulations. However, Drake and DDrake differ dramatically in their regional climates. The small and large basins of DDrake exhibit distinctive Atlantic-like and Pacific-like characteristics, respectively: the small basin is warmer, saltier, and denser at the surface than the large basin, and is the main site of deep water formation with a deep overturning circulation and strong northward ocean heat transport. A sensitivity experiment with DDrake demonstrates that the salinity contrast between the two basins, and hence the localization of deep convection, results from a deficit of precipitation, rather than an excess of evaporation, over the small basin. It is argued that the width of the small basin relative to the zonal fetch of atmospheric precipitation is the key to understanding this salinity contrast. Finally, it is argued that many gross features of the present climate are consequences of two topological asymmetries that have profound effects on ocean circulation: a meridional asymmetry (circumpolar flow in the Southern Hemisphere; blocked flow in the Northern Hemisphere) and a zonal asymmetry (a small basin and a large basin).

Ocean heat transport and water vapor greenhouse in a warm equable climate: a new look at the low gradient paradox

The authors study the role of ocean heat transport (OHT) in the maintenance of a warm, equable, ice-free climate. An ensemble of idealized aquaplanet GCM calculations is used to assess the equilibrium sensitivity of global mean surface temperature and its equator-to-pole gradient (ΔT) to variations in OHT, prescribed through a simple analytical formula representing export out of the tropics and poleward convergence. Low-latitude OHT warms the mid- to high latitudes without cooling the tropics; increases by 1°C and ΔT decreases by 2.6°C for every 0.5-PW increase in OHT across 30° latitude. This warming is relatively insensitive to the detailed meridional structure of OHT. It occurs in spite of near-perfect atmospheric compensation of large imposed variations in OHT: the total poleward heat transport is nearly fixed. The warming results from a convective adjustment of the extratropical troposphere. Increased OHT drives a shift from large-scale to convective precipitation in the midlatitude storm tracks. Warming arises primarily from enhanced greenhouse trapping associated with convective moistening of the upper troposphere. Warming extends to the poles by atmospheric processes even in the absence of high-latitude OHT. A new conceptual model for equable climates is proposed, in which OHT plays a key role by driving enhanced deep convection in the midlatitude storm tracks. In this view, the climatic impact of OHT depends on its effects on the greenhouse properties of the atmosphere, rather than its ability to increase the total poleward energy transport.

Sodium chloride added to transport water and physiological responses of Matrinxã Brycon amazonicus (Teleost: Characidae)

A adição de sal à água tem sido utilizada para a mitigação de estresse e aumento da taxa de sobrevivência em peixes. O presente estudo avaliou o efeito do cloreto de sódio (0,0; 1,0; 3,0 e 6.0 g/l) nas concentrações de cortisol plasmático, glicemia, triglicerídios, proteínas total plasmática, hematócrito, hemoglobina, número de eritrócitos, glicogênio e lipídio hepáticos, e lipídio muscular em matrinxã Brycon amazonicum adultos após quatro horas de transporte e durante período de recuperação de 96 h. Amostras foram coletadas antes e depois do transporte, bem como 24 e 96 h após a chegada. O nível de cortisol plasmático estava mais elevado logo após o transporte quando comparado à condição inicial (pré-transporte), exceto para os peixes transportados com sal nas concentrações 3,0 e 6,0 g/l. Comportamento semelhante foi observado para a glicemia, porém os peixes dos tratamentos 0,0, 1,0 e 3,0 g/l necessitaram de período superior a 24 h para recuperar a condição inicial. Foram registrados níveis mais baixos de glicogênio hepático em peixes do tratamento controle (0,0 g/l). Os parâmetros hemoglobina, número de eritrócitos, proteína plasmática total e lipídio hepático não apresentaram alterações durante o período experimental. Os valores de hematócrito diminuíram logo após o transporte em todos os tratamentos, retornando aos níveis iniciais após 24 h. Todos os tratamentos apresentaram redução nos níveis de lipídio muscular e triglicerídios durante o período de recuperação. Os resultados sugerem que a adição de 6,0 g/l de sal na água de transporte reduz as alterações fisiológicas de estresse e que é necessário período de 96 h após o transporte para a recuperação da condição inicial de matrinxãs transportados sem a adição de sal.

Effects of twenty-four hour transport or twenty-four hour feed and water deprivation on physiologic and performance responses of feeder cattle

The objective of this study was to compare the effects of 24-h road transport or 24-h feed and water deprivation on acute-phase and performance responses of feeder cattle. Angus x Hereford steers (n = 30) and heifers (n = 15) were ranked by gender and BW (217 +/- 3 kg initial BW; 185 +/- 2 d initial age) and randomly assigned to 15 pens on d -12 of the experiment (3 animals/pen; 2 steers and 1 heifer). Cattle were fed alfalfa-grass hay ad libitum and 2.3 kg/animal daily (DM basis) of a corn-based concentrate throughout the experiment (d -12 to 28). on d 0, pens were randomly assigned to 1 of 3 treatments: 1) transport for 24 h in a livestock trailer for 1,200 km (TRANS), 2) no transport but feed and water deprivation for 24 h (REST), or 3) no transport and full access to feed and water (CON). Treatments were concurrently applied from d 0 to d 1. Total DMI was evaluated daily from d -12 to d 28. Full BW was recorded before treatment application (d -1 and 0) and at the end of experiment (d 28 and 29). Blood samples were collected on d 0, 1, 4, 7, 10, 14, 21, and 28. Mean ADG was greater (P < 0.01) in CON vs. TRANS and REST cattle but similar (P = 0.46) between TRANS and REST cattle (1.27, 0.91, and 0.97 kg/d, respectively; SEM = 0.05). No treatment effects were detected for DMI (P >= 0.25), but CON had greater G: F vs. TRANS (P < 0.01) and REST cattle (P = 0.08) whereas G: F was similar (P = 0.21) between TRANS and REST cattle. Plasma cortisol concentrations were greater (P <= 0.05) in REST vs. CON and TRANS cattle on d 1, 7, 14, and 28 and also greater (P = 0.02) in TRANS vs. CON cattle on d 1. Serum NEFA concentrations were greater (P < 0.01) in REST and TRANS vs. CON cattle on d 1 and greater (P < 0.01) in REST vs. TRANS cattle on d 1. Plasma ceruloplasmin concentrations were greater (P = 0.04) in TRANS vs. CON cattle on d 1, greater (P = 0.05) in REST vs. CON on d 4, and greater (P <= 0.05) in REST vs. TRANS and CON on d 14. Plasma haptoglobin concentrations were greater (P < 0.01) in TRANS vs. CON and REST cattle on d 1 and greater (P <= 0.05) for REST vs. TRANS and CON cattle on d 7. In conclusion, 24-h transport and 24-h nutrient deprivation elicited acute-phase protein reactions and similarly reduced feedlot receiving performance of feeder cattle. These results suggest that feed and water deprivation are major contributors to the acute-phase response and reduced feedlot receiving performance detected in feeder cattle transported for long distances.

Simulations of Ground-Water Flow, Transport, Age, and Particle Tracking near York, Nebraska, for a Study of Transport of Anthropogenic and Natural Contaminants (TANC) to Public-Supply Wells

The U.S. Geological Survey (USGS) is committed to providing the Nation with credible scientific information that helps to enhance and protect the overall quality of life and that facilitates effective management of water, biological, energy, and mineral resources (http://www.usgs.gov/). Information on the Nation’s water resources is critical to ensuring long-term availability of water that is safe for drinking and recreation and is suitable for industry, irrigation, and fish and wildlife. Population growth and increasing demands for water make the availability of that water, now measured in terms of quantity and quality, even more essential to the long-term sustainability of our communities and ecosystems. The USGS implemented the National Water-Quality Assessment (NAWQA) Program in 1991 to support national, regional, State, and local information needs and decisions related to water-quality management and policy (http://water.usgs.gov/nawqa). The NAWQA Program is designed to answer: What is the condition of our Nation’s streams and ground water? How are conditions changing over time? How do natural features and human activities affect the quality of streams and ground water, and where are those effects most pronounced? By combining information on water chemistry, physical characteristics, stream habitat, and aquatic life, the NAWQA Program aims to provide science-based insights for current and emerging water issues and priorities. From 1991-2001, the NAWQA Program completed interdisciplinary assessments and established a baseline understanding of water-quality conditions in 51 of the Nation’s river basins and aquifers, referred to as Study Units (http://water.usgs.gov/nawqa/studyu.html).

Ionic Transport and Water Vapor Uptake of Ammonium Exchanged Perfluorosulfonic Acid Membranes

Nafion membranes series N117 doped with ammonium, at different cation fractions (H+/NH4+), were investigated for ionic transport and water vapor uptake, for several water activities and temperatures. Ammonium cations change both properties of the polymer in a similar manner. Membrane ionic conductivity and water vapor uptake (lambda) decrease as the ammonium concentration increases in the polymer. Ionic transport activation energies are calculated and the transport mechanism of ammonium ions in Nafion is discussed. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.040203jes] All rights reserved.

Water masses, mass transport and variability of the Canary current in autumn

Máster en Oceanografía