Theory of the diffusion and sorption of various substances through a biporous sorbent membrane with constant concentration difference at its boundaries

1981 ◽  
Vol 30 (1) ◽  
pp. 58-61
Author(s):  
V. I. Ulin ◽  
P. P. Zolotarev
Keyword(s):  
Constant Concentration ◽  
Concentration Difference ◽  
Biporous Sorbent

The Onset of Thermohaline Convection in a Linearly-Stratified Horizontal Layer

1976 ◽  
Vol 98 (4) ◽  
pp. 558-563 ◽  
Author(s):  
J. H. Wright ◽  
R. I. Loehrke
Keyword(s):  
Porous Metal ◽  
Horizontal Layer ◽  
Free Boundaries ◽  
Constant Concentration ◽  
Concentration Difference ◽  
Thermohaline Convection ◽  
Metal Plates ◽  
Convective Motions ◽  
Fixed Constant ◽  
Rayleigh Numbers

The convective stability of a horizontal layer of water with salt and heat addition from below was studied experimentally. The layer was bounded above and below by porous metal plates through which heat and salt could diffuse. A well-mixed region of warm, salty water below the lower plate and another of cooler, fresher water above the upper plate set the temperature and concentration difference for the intervening quiescent layer. With a fixed, constant concentration gradient established between the plates the temperature difference was slowly increased until convective motions were observed. The instability boundary for this system lies within the unstable region predicted by linear theory for a horizontal layer with constant gradients and stress-free boundaries and approaches the linear boundary at high Rayleigh numbers.

The effect of electrondonors on the polymerization kinetics of isoprene

1980 ◽  
Vol 45 (12) ◽  
pp. 3338-3346
Author(s):  
Miroslav Kašpar ◽  
Jiří Trekoval
Keyword(s):  
Induction Period ◽  
Ethyl Ether ◽  
Reaction Order ◽  
Propagation Rate ◽  
Reaction Scheme ◽  
Polymerization Kinetics ◽  
Polymerization Rate ◽  
Constant Concentration ◽  
Initial Concentration ◽  
Kinetics Of

The effect of small additions of 1-octene, butyl ethyl ether and triethylamine on the polymerization kinetics of isoprene (2-methyl-1,3-butadiene) in benzene initiated with butyllithium was investigated by employing the GLC analysis. The addition of 1-octane was reflected only in a shorter induction period of the reaction; the effect on the propagation rate was insignificant. With the increasing amount of butyl ethyl ether, the polymerization rate increases linearly, while the reaction order with respect to the concentration of triethylamine is variable and increases from 0.33 to 0.66 with the increasing concentration of the initiator. For a constant concentration of triethylamine, the reaction order with respect to the initial concentration of the initiator was found to vary considerably, reaching even negative values. A reaction scheme was suggested, taking into account the competition between two different solvates of alkyllithium.

scholarly journals A Novel Iron Chloride Red-Ox Concentration Flow Cell Battery (ICFB) Concept; Power and Electrode Optimization

Energies ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 1109
Author(s):  
Robert Bock ◽  
Björn Kleinsteinberg ◽  
Bjørn Selnes-Volseth ◽  
Odne Stokke Burheim
Keyword(s):  
Energy Storage ◽  
Large Scale ◽  
Fossil Fuels ◽  
Flow Cell ◽  
Iron Chloride ◽  
Carbon Electrodes ◽  
Concentration Difference ◽  
Term Energy ◽  
Short And Long Term

For renewable energies to succeed in replacing fossil fuels, large-scale and affordable solutions are needed for short and long-term energy storage. A potentially inexpensive approach of storing large amounts of energy is through the use of a concentration flow cell that is based on cheap and abundant materials. Here, we propose to use aqueous iron chloride as a reacting solvent on carbon electrodes. We suggest to use it in a red-ox concentration flow cell with two compartments separated by a hydrocarbon-based membrane. In both compartments the red-ox couple of iron II and III reacts, oxidation at the anode and reduction at the cathode. When charging, a concentration difference between the two species grows. When discharging, this concentration difference between iron II and iron III is used to drive the reaction. In this respect it is a concentration driven flow cell redox battery using iron chloride in both solutions. Here, we investigate material combinations, power, and concentration relations.

PENETRATION OF RADIOACTIVE ISOPROPYL METHYLPHOSPHONOFLUORIDATE (SARIN) VAPOR THROUGH SKIN

1960 ◽  
Vol 38 (9) ◽  
pp. 935-944 ◽  
Author(s):  
M. K. McPhail ◽  
P. A. Adie
Keyword(s):  
Exposure Time ◽  
Vapor Concentration ◽  
Constant Concentration ◽  
Time Required

Studies have been made of the penetration of sarin (isopropyl methylphosphonofluoridate) tagged with P32 through the skin of rabbits. Sarin vapor at a constant concentration was passed through a plastic cup attached to the clipped bellies of rabbits. Using different sizes of cups it has been found that the L(ct)50 (concentration × exposure time required to kill 50% of the animals exposed) decreased as the exposure area was increased. From these experiments it was possible to determine how absorption through skin varies with area exposed, vapor concentration, and exposure time and to find the approximate 'ct' necessary to kill a rabbit for any area of skin exposed.

The Influence of Auxins on the Biosynthesis of Isoprene Derivatives in Callus Cultures of Vaccinium corymbosum var. bluecrop

2006 ◽  
Vol 61 (7-8) ◽  
pp. 565-570 ◽  
Author(s):  
Piotr Migas ◽  
Maria Łuczkiewicz ◽  
Wojciech Cisowski
Keyword(s):  
Quantitative Analysis ◽  
Vaccinium Corymbosum ◽  
Callus Cultures ◽  
Constant Concentration ◽  
Triterpene Synthesis

Callus cultures of Vaccinium corymbosum var. bluecrop were optimized for their isoprene derivatives production by supplementing Schenk-Hildebrandt (SH) medium with constant concentration of kinetin (2.32 μᴍ) and two different amounts of selected auxins. Every auxin, except for IBA, used in 10-time higher concentration (2,4D, NAA, IAA, NOA) stimulated biosynthesis of β-sitosterol and inhibited triterpene synthesis. Quantitative analysis of isoprene derivatives in callus biomass collected on the 25th day of the experiment proved that the analyzed callus of Vaccinium corymbosum var. bluecrop synthesized the highest amount of isoprene derivatives after subculturing on SH medium modified with 22.6 μᴍ of 2,4D and 2.32 μᴍ of kinetin.

First-pass of GTS-21 on canine gut wall and liver determined by portal–systemic concentration difference

2001 ◽  
Vol 14 (2) ◽  
pp. 159-165 ◽  
Author(s):  
Ryotaro Azuma ◽  
Tomio Hirota ◽  
Hiroshi Manabe ◽  
Masahito Komuro ◽  
Hiroshi Kiwada
Keyword(s):  
Concentration Difference ◽  
First Pass

Inhibition of Adenosine Triphosphatases in Vitro by Silver Nitrate and Silver Sulfadiazine

1984 ◽  
Vol 3 (1) ◽  
pp. 37-42 ◽  
Author(s):  
B. R. Nechay ◽  
J. P. Saunders
Keyword(s):  
Silver Nitrate ◽  
Aqueous Suspension ◽  
Human Kidney ◽  
Silver Sulfadiazine ◽  
Constant Concentration ◽  
Inhibitory Potency ◽  
Adenosine Triphosphatases ◽  
Tissue Homogenates ◽  
Atpase Inhibition

Inhibition of adenosine triphosphatase (ATPase) by silver nitrate (AgNO3) in vitro was studied in microsomal fractions or tissue homogenates of canine brain and kidney and human kidney. In microsomal fractions, AgNO3 was an indiscriminate inhibitor of ouabain-sensitive (Na+ + K+ ATPase) and ouabain-insensitive (Mg2+ ATPase) activities, with 50% inhibition obtaining at concentrations on the order of 10–7 to 10–6 M. Changing the concentrations of Na+, K+, H+, Mg2+, and ATP did not alter the fractional inhibition of Na+ + K+ ATPase by a constant concentration of AgNO3. An aqueous suspension of silver sulfadiazine had an inhibitory potency similar to AgNO3. It was concluded that silver gives a different pattern of Na+ + K+ ATPase inhibition than other metallic inhibitors of the enzyme so far examined.

Electrokinetic Power Generation by Forward Osmosis

2012 ◽  
Author(s):  
Kar Cherng Hon ◽  
Chun Yang ◽  
Seow Chay Low
Keyword(s):  
Power Generation ◽  
Salinity Gradient ◽  
Forward Osmosis ◽  
Streaming Potential ◽  
Nacl Solution ◽  
Direct Power ◽  
Concentration Difference ◽  
Permeable Membrane ◽  
Flat Sheet ◽  
Novel Method

In this paper, an innovative direct power generation technique from salinity gradient is proposed and demonstrated. The basis of this novel method encompasses forward osmosis (FO) and electrokinetic (EK) principles. Tapping the concentration difference between seawater and river fresh water, forward osmosis (FO) is utilized to allow for spontaneously transporting water across a semi-permeable membrane. The flow of water is then directed towards array of microchannels in the form of porous medium where power is produced from the electrokinetical streaming potential. Experimentally, NaCl solution and DI water were used to model as seawater and fresh river water, respectively. Both glass and polymer based porous media and commercial flat sheet FO membranes were employed herein. Results show power density could reach the order of 101W/m2. Having features of ease of fabrication, simple configuration and no mechanical moving parts, this method provides a feasible mean to harvest enormous energy from salinity gradient. Thus the proposed technique could contribute greatly to renewable energy and towards sustainable future.

Capacité calorifique de polyélectrolytes en solution

1985 ◽  
Vol 63 (7) ◽  
pp. 1568-1571 ◽  
Author(s):  
Hubert Daoust ◽  
Hoa Le Thanh ◽  
Pierre Ferland ◽  
Daniel St-Cyr
Keyword(s):  
Heat Capacity ◽  
Sodium Salt ◽  
Polyacrylic Acid ◽  
Molar Heat Capacity ◽  
Conformational Transformation ◽  
Polymethacrylic Acid ◽  
High Dilution ◽  
Constant Concentration ◽  
Apparent Molar Heat Capacity ◽  
Low Concentrations

Heat capacities of polyelectrolytes in aqueous solutions have been measured at 25 °C using a Picker-type dynamic micro-calorimeter. The precision of the apparatus is such that it is possible to calculate the apparent molar heat capacity [Formula: see text] of the solute, even at high dilution. The polymers that were studied include polymethacrylic acid (PMAH) and polyacrylic acid (PAH), as well as its sodium salt and the sodium salt of the polystyrènesulfonate. For the salts, the results show that the value of [Formula: see text] decreases rapidly with dilution to low concentrations; this result is in perfect concordance with a relation derived from the theory of Lifson and Katchalsky. A study of the variation of [Formula: see text] at a constant concentration, with the extent of the neutralization of the acids PMAH and PAH has also been conducted. As has been shown previously, the chain of the PMAH undergoes a conformational transformation when the level of neutralization gets close to 25%. This transformation implies an increase of the value of [Formula: see text] [Journal translation]

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