Simple Theoretical Model for Ion Cooperativity in Aqueous Solutions of Simple Inorganic Salts and Its Effect on Water Surface Tension

Flotation data on copper-bearing shale in aqueous solutions of inorganic electrolytes (NaCl, Na2SO4, KPF6, NH4Cl) and organic reagents (ethylamine, propylamine) as frothers were presented and discussed. The relationships between shale flotation, surface tension of aqueous solution and foam height during bubbling with air in the flotation system were presented. It has been found that flotation of shale in the presence of inorganic salts the yield was directly proportional to the surface tension of the aqueous solution of salt and inversely proportional to the height of the foam. On the other hand, for organic reagents solutions (short chain amines), a reverse effect has been observed in relation to the inorganic compounds studied, that is the yield of copper-bearing shale flotation and the foam height were inversely proportional to the surface tension of the amine solution.

Download Full-text

ISOTOPE EFFECTS ON MOLAR VOLUME AND SURFACE TENSION: SIMPLE THEORETICAL MODEL AND EXPERIMENTAL DATA FOR HYDROCARBONS

10.2172/4540065 ◽

1965 ◽

Author(s):

L Bartell ◽

R Roskos

Keyword(s):

Experimental Data ◽

Surface Tension ◽

Theoretical Model ◽

Molar Volume ◽

Isotope Effects ◽

Simple Theoretical Model

Download Full-text

Immunoferritin localization of intracellular antigens in positively stained frozen sections

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010008170x ◽

1978 ◽

Vol 36 (2) ◽

pp. 168-169

Author(s):

K. T. Tokuyasu

Keyword(s):

Surface Tension ◽

Water Surface ◽

Thin Layers ◽

The Other ◽

Positive Staining ◽

Frozen Sections ◽

The Past ◽

Ultrathin Frozen Sections ◽

Definition Of

During the past investigations of immunoferritin localization of intracellular antigens in ultrathin frozen sections, we found that the degree of negative staining required to delineate u1trastructural details was often too dense for the recognition of ferritin particles. The quality of positive staining of ultrathin frozen sections, on the other hand, has generally been far inferior to that attainable in conventional plastic embedded sections, particularly in the definition of membranes. As we discussed before, a main cause of this difficulty seemed to be the vulnerability of frozen sections to the damaging effects of air-water surface tension at the time of drying of the sections.Indeed, we found that the quality of positive staining is greatly improved when positively stained frozen sections are protected against the effects of surface tension by embedding them in thin layers of mechanically stable materials at the time of drying (unpublished).

Download Full-text

Incumbent and Entrant Bidding in Scoring Rule Auctions: A Study on Italian Canteen Services

The B E Journal of Economic Analysis & Policy ◽

10.1515/bejeap-2019-0146 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Riccardo Camboni ◽

Paola Valbonesi

Keyword(s):

Theoretical Model ◽

Production Cost ◽

Specific Information ◽

Scoring Rule ◽

The Public ◽

Simple Theoretical Model ◽

Original Dataset

AbstractWe empirically investigate incumbents’ and entrants’ bids on an original dataset of 192 scoring rule auctions for canteen services in Italy. Our findings show that winning rebates are lower (i.e., prices paid by the public buyer are higher) when the contract is awarded to the incumbent supplier. This result is not explained by the observable characteristics of the auction or the service awarded. We develop a simple theoretical model showing that the result is consistent with a setting in which the buyer exploits specific information on the incumbent supplier’s production cost.

Download Full-text

Adsorption Properties of Hydrocarbon and Fluorocarbon Surfactants Ternary Mixture at the Water-Air Interface

Molecules ◽

10.3390/molecules26144313 ◽

2021 ◽

Vol 26 (14) ◽

pp. 4313

Author(s):

Bronisław Jańczuk ◽

Katarzyna Szymczyk ◽

Anna Zdziennicka

Keyword(s):

Surface Tension ◽

Water Surface ◽

Standard Free Energy ◽

Ternary Mixtures ◽

Free Energy Of Adsorption ◽

Interface Tension ◽

Air Interface ◽

Surface Excess Concentration ◽

Tail Water ◽

Triton X

Measurements were made of the surface tension of the aqueous solutions of p-(1,1,3,3-tetramethylbutyl) phenoxypoly(ethylene glycols) having 10 oxyethylene groups in the molecule (Triton X-100, TX100) and cetyltrimethylammonium bromide (CTAB) with Zonyl FSN-100 (FC6EO14, FC1) as well as with Zonyl FSO-100 (FC5EO10, FC2) ternary mixtures. The obtained results were compared to those provided by the Fainerman and Miller equation and to the values of the solution surface tension calculated, based on the contribution of a particular surfactant in the mixture to the reduction of water surface tension. The changes of the aqueous solution ternary surfactants mixture surface tension at the constant concentration of TX100 and CTAB mixture at which the water surface tension was reduced to 60 and 50 mN/m as a function of fluorocarbon surfactant concentration, were considered with regard to the composition of the mixed monolayer at the water-air interface. Next, this composition was applied for the calculation of the concentration of the particular surfactants in the monolayer using the Frumkin equation. On the other hand, the Gibbs surface excess concentration was determined only for the fluorocarbon surfactants. The tendency of the particular surfactants to adsorb at the water-air interface was discussed, based on the Gibbs standard free energy of adsorption which was determined using different methods. This energy was also deduced, based on the surfactant tail surface tension and tail-water interface tension.

Download Full-text

Market Choices Driven by Reference Groups: A Comparison of Analytical and Simulation Results on Random Networks

Entropy ◽

10.3390/e23081007 ◽

2021 ◽

Vol 23 (8) ◽

pp. 1007

Author(s):

Michał Ramsza

Keyword(s):

Theoretical Model ◽

Reference Group ◽

Third Party ◽

Qualitative Behavior ◽

Reference Groups ◽

Group Influence ◽

Simple Theoretical Model ◽

High Connectivity ◽

Simulation Results ◽

Two Equilibria

The present paper reports simulation results for a simple model of reference group influence on market choices, e.g., brand selection. The model was simulated on three types of random graphs, Erdos–Renyi, Barabasi–Albert, and Watts–Strogatz. The estimates of equilibria based on the simulation results were compared to the equilibria of the theoretical model. It was verified that the simulations exhibited the same qualitative behavior as the theoretical model, and for graphs with high connectivity and low clustering, the quantitative predictions offered a viable approximation. These results allowed extending the results from the simple theoretical model to networks. Thus, by increasing the positive response towards the reference group, the third party may create a bistable situation with two equilibria at which respective brands dominate the market. This task is easier for large reference groups.

Download Full-text

Surface Thermodynamics, Viscosity, Activation Energy of N-Methyldiethanolamine Aqueous Solutions Promoted by Tetramethylammonium Arginate

Entropy ◽

10.3390/e22121337 ◽

2020 ◽

Vol 22 (12) ◽

pp. 1337

Author(s):

Xiangfeng Tian ◽

Lemeng Wang ◽

Pan Zhang ◽

Dong Fu

Keyword(s):

Activation Energy ◽

Surface Tension ◽

Diffusion Coefficient ◽

Aqueous Solutions ◽

Quantitative Relationship ◽

Viscosity Data ◽

Surface Thermodynamics ◽

Surface Entropy ◽

Operation Conditions ◽

Surface Enthalpy

The surface tension and viscosity values of N-methyldiethanolamine (MDEA) aqueous solutions promoted by tetramethylammonium arginate ([N1111][Arg]) were measured and modeled. The experimental temperatures were 303.2 to 323.2 K. The mass fractions of MDEA (wMDEA) and [N1111][Arg] (w[N1111][Arg]) were 0.300 to 0.500 and 0.025 to 0.075, respectively. The measured surface tension and viscosity values were satisfactorily fitted to thermodynamic models. With the aid of experimentally viscosity data, the activation energy (Ea) and H2S diffusion coefficient (DH2S) of MDEA-[N1111][Arg] aqueous solution were deduced. The surface entropy and surface enthalpy of the solutions were calculated using the fitted model of the surface tension. The quantitative relationship between the calculated values (surface tension, surface entropy, surface enthalpy, viscosity, activation energy, and H2S diffusion coefficient) and the operation conditions (mass fraction and temperature) was demonstrated.

Download Full-text