Solubility of nonpolar gases in halogenated compounds. 1. Solubility of hydrogen, deuterium, nitrogen, oxygen, methane, ethylene, ethane, carbon tetrafluoride, sulfur hexafluoride and carbon dioxide in chlorocyclohexane at 263.15-303.15 K and 101.32 kPa of partial pressure of gas

An increased demand for energy in recent decades has caused an increase in the emissions of combustion products, among which carbon-dioxide is the most harmful. As carbon-dioxide induces negative environmental effects, like global warming and the greenhouse effect, a decrease of the carbon-dioxide emission has emerged as one of the most urgent tasks in engineering. In this work, the possibility for the application of the polymer-based, dense, mixed matrix membranes for flue gas treatment was tested. The task was to test a potential decrease in the permeability and selectivity of a mixed-matrix membrane in the presence of moisture and at elevated temperature. Membranes are based on two different poly(ethylene oxide)-based polymers filled with two different zeolite powders (ITR and IWS). An additive of detergent type was added to improve the contact properties between the zeolite and polymer matrix. The measurements were performed at three different temperatures (30, 60, and 90 °C) under wet conditions, with partial pressure of the water equal to the vapor pressure of the water at the given temperature. The permeability of carbon-dioxide, hydrogen, nitrogen, and oxygen was measured, and the selectivity of the carbon-dioxide versus other gases was determined. Obtained results have shown that an increase of temperature and partial pressure of the vapor slightly increase both the selectivity and permeability of the synthesized membranes. It was also shown that the addition of the zeolite powder increases the permeability of carbon-dioxide while maintaining the selectivity, compared to hydrogen, oxygen, and nitrogen.

Download Full-text

A new technique to analyse threshold-intensities based on time dependent change-points in the ratio of minute ventilation and end-tidal partial pressure of carbon-dioxide production

Respiratory Physiology & Neurobiology ◽

10.1016/j.resp.2021.103735 ◽

2021 ◽

pp. 103735

Author(s):

Ozgur Ozkaya ◽

Gorkem A. Balci ◽

Hakan As ◽

Engin Yildiztepe

Keyword(s):

Carbon Dioxide ◽

Partial Pressure ◽

Minute Ventilation ◽

Carbon Dioxide Production ◽

Time Dependent ◽

Change Points ◽

Dependent Change ◽

Time Dependent Change ◽

A New Technique ◽

End Tidal

Download Full-text

Effect of vegetation on limestone solution in a small High Arctic basin

Canadian Journal of Earth Sciences ◽

10.1139/e77-059 ◽

1977 ◽

Vol 14 (4) ◽

pp. 571-581 ◽

Cited By ~ 19

Author(s):

Ming-Ko Woo ◽

Philip Marsh

Keyword(s):

Carbon Dioxide ◽

Partial Pressure ◽

Soil Water ◽

Water Hardness ◽

Late Summer ◽

Arctic Basin ◽

The Arctic ◽

Total Hardness ◽

Equilibrium Partial Pressure ◽

Biogenic Carbon

To evaluate the effect of tundra vegetation on limestone solution processes, the present study was carried out in a small basin in southwestern Ellesmere Island, N.W.T. A test reach was selected along the stream, and water samples were collected at regular intervals from a seepage point entering the reach, a soil water pit at the bottom of a vegetated slope along the test reach, and from the stream at the outlet of the reach. Hydrochemical characteristics of the samples were described by several measured and calculated variables including water temperature, pH, calcium and total hardness, bicarbonate concentration, equilibrium partial pressure of carbon dioxide, and indices of saturation with respect to calcite and dolomite. Throughout the growing season of 1975, all samples indicated higher concentrations in water hardness and in bicarbonate than those reported in nonvegetated areas of the Arctic. A rising trend was apparent in these data, with the concentrations reaching a seasonal maximum in late summer. These phenomena are attributed to the production of biogenic carbon dioxide, which increased the aggressiveness of the water. The partial pressure of carbon dioxide in soil water was directly increased by this process, while the addition of soil water to the stream caused noticeable downstream increase in partial pressure of carbon dioxide and a corresponding reduction in saturation with respect to calcite and to dolomite. The influence of vegetation was therefore very marked in both surface and in subsurface flows.

Download Full-text