scholarly journals Coumarin 153 Dynamics in Ethylammonium Nitrate: The Effects of Dilution with Methanol

2021 ◽  
Vol 2 (4) ◽  
pp. 778-795
Author(s):  
Mark P. Heitz ◽  
Tyler J. Sabo ◽  
Stephanie M. Robillard
Keyword(s):  
Steady State ◽  
Mole Fraction ◽  
Marked Change ◽  
Hydrodynamic Theory ◽  
Binary Solvent ◽  
Magic Angle ◽  
Anionic Dyes ◽  
Model Framework ◽  
Coumarin 153 ◽  
Ethylammonium Nitrate

Magic angle intensity decay and dynamic fluorescence anisotropy measurements were made on the binary solvent system composed of ethylammonium nitrate ([N2,0,0,0+][NO3−], EAN) + methanol (MeOH) across the complete EAN mole fraction range (xIL = 0–1) using the neutral dipolar solute coumarin 153 (C153) at 295 K. Stokes–Einstein–Debye (SED) hydrodynamic theory was used as a model framework to assess the C153 rotational reorientation dynamics. Departure from stick SED prediction was observed (in contrast to literature reports that used cationic or anionic dyes) and indicated a significant influence of domain nanoheterogeneity on probe dynamics. Steady-state spectroscopy indicated minimal changes in spectral peak and width with mole fraction, except at xIL = 0.3 where absorption widths decreased by ~170 cm−1, signaling that C153 sensed a change in solution heterogeneity. Magic angle intensity decays corroborated the steady-state observation and the excited-state lifetimes showed a marked change from xIL = 0.2–0.4 where EAN-EAN interactions became notably more significant. C153 average rotation times (⟨τrot⟩) showed significant solvent decoupling with increased EAN. The rotational data were fit to a power law dependence, ⟨τrot⟩ ∝ (ηT)p, where p = 0.82, demonstrating the presence of dynamic heterogeneity in the EAN/MeOH solutions. With increased EAN, rotation times showed that the heterogeneity became increasingly more significant since the rotation times systematically decreased away from the hydrodynamic stick limit.

scholarly journals Experimental and Computational Approaches for Solubility Measurement of Pyridazinone Derivative in Binary (DMSO + Water) Systems

Molecules ◽  
2019 ◽  
Vol 25 (1) ◽  
pp. 171 ◽  
Author(s):  
Faiyaz Shakeel ◽  
Sultan Alshehri ◽  
Mohd Imran ◽  
Nazrul Haq ◽  
Abdullah Alanazi ◽  
...  
Keyword(s):  
Computational Model ◽  
Mole Fraction ◽  
Research Work ◽  
Solvent System ◽  
Binary Solvent ◽  
Thermodynamic Evaluation ◽  
Computational Approaches ◽  
Neat Water ◽  
Poorly Soluble ◽  
Binary Solvent Systems

The current research work was performed to evaluate the solubilization behavior, solution thermodynamics, and solvation behavior of poorly soluble pyridazinone derivative i.e., 6-phenyl-pyridazin-3(2H)-one (PPD) in various binary solvent systems of dimethyl sulfoxide (DMSO) and water using experimental and various computational approaches. The solubility of PPD in various binary solvent system of DMSO and water was investigated within the temperature range T = 298.2 K to 318.2 K at constant air pressure p = 0.1 MPa, by employing an isothermal technique. The generated solubility data of PPD was computationally represented by five different cosolvency models including van’t Hoff, Apelblat, Yalkowsky–Roseman, Jouyban–Acree, and Jouyban–Acree–van’t Hoff models. The performance of each computational model for correlation studies was illustrated using root mean square deviations (RMSD). The overall RMSD value was obtained <2.0% for each computational model. The maximum solubility of PPD in mole fraction was recorded in neat DMSO (4.67 × 10−1 at T = 318.2 K), whereas the lowest one was obtained in neat water (5.82 × 10−6 at T = 298.2 K). The experimental solubility of PPD in mole fraction in neat DMSO was much higher than its ideal solubility, indicating the potential of DMSO for solubility enhancement of PPD. The computed values of activity coefficients showed maximum molecular interaction in PPD-DMSO compared with PPD-water. Thermodynamic evaluation showed an endothermic and entropy-driven dissolution of PPD in all the mixtures of DMSO and water. Additionally, enthalpy–entropy compensation evaluation indicated an enthalpy-driven mechanism as a driven mechanism for the solvation property of PPD.

The Effect of Lubricant Inertia in Journal-Bearing Lubrication

1957 ◽  
Vol 24 (4) ◽  
pp. 494-496
Author(s):  
J. F. Osterle ◽  
Y. T. Chou ◽  
E. A. Saibel
Keyword(s):  
Reynolds Number ◽  
Steady State ◽  
Reynolds Equation ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Hydrodynamic Theory ◽  
Simple Relationship ◽  
Inertia Effect ◽  
Laminar Regime ◽  
Steady State Operation

Abstract The Reynolds equation of hydrodynamic theory, modified to take lubricant inertia into approximate account, is applied to the steady-state operation of journal bearings to determine the effect of lubricant inertia on the pressure developed in the lubricant. A simple relationship results, relating this “inertial” pressure to the Reynolds number of the flow. It is found that the inertia effect can be significant in the laminar regime.

scholarly journals Beyond the bucket – Developing a global gradient-based groundwater model (G<sup>3</sup>M v1.0) for a global hydrological model from scratch

2018 ◽  
Author(s):  
Robert Reinecke ◽  
Laura Foglia ◽  
Steffen Mehl ◽  
Tim Trautmann ◽  
Denise Cáceres ◽  
...  
Keyword(s):  
Steady State ◽  
Capillary Rise ◽  
Hydrological Models ◽  
Grid Cells ◽  
Reservoir Model ◽  
Model Framework ◽  
Water Flows ◽  
Macro Scale ◽  
Gradient Based ◽  
The Impact

Abstract. To quantify water flows between groundwater (GW) and surface water (SW) as well as the impact of capillary rise on evapotranspiration by global hydrological models (GHMs), it is necessary to replace the bucket-like linear GW reservoir model typical for hydrological models with a fully integrated gradient-based GW flow model. Linear reservoir models can only simulate GW discharge to SW bodies, provide no information on the location of the GW table and assume that there is no GW flow among grid cells. A gradient-based GW model simulates not only GW storage but also hydraulic head, which together with information on SW table elevation enables the quantification of water flows from GW to SW and vice versa. In addition, hydraulic heads are the basis for calculating lateral GW flow among grid cells and capillary rise. G3M is a new global gradient-based GW model with a spatial resolution of 5' that will replace the current linear GW reservoir in the 0.5° WaterGAP Global Hydrology Model (WGHM). The newly developed model framework enables in-memory coupling to WGHM while keeping overall runtime relatively low, allowing sensitivity analyses and data assimilation. This paper presents the G3M concept and specific model design decisions together with results under steady-state naturalized conditions, i.e. neglecting GW abstractions. Cell-specific conductances of river beds, which govern GW-SW interaction, were determined based on the 30'' steady-state water table computed by Fan et al. (2013). Together with an appropriate choice for the effective elevation of the SW table within each grid cell, this enables a reasonable simulation of drainage from GW to SW such that, in contrast to the GW model of de Graaf et al. (2015, 2017), no additional drainage based on externally provided values for GW storage above the floodplain is required in G3M. Comparison of simulated hydraulic heads to observations around the world shows better agreement than de Graaf et al. (2015). In addition, G3M output is compared to the output of two established macro-scale models for the Central Valley, California, and the continental United States, respectively. As expected, depth to GW table is highest in mountainous and lowest in flat regions. A first analysis of losing and gaining rivers and lakes/wetlands indicates that GW discharge to rivers is by far the dominant flow, draining diffuse GW recharge, such that lateral flows only become a large fraction of total diffuse and focused recharge in case of losing rivers and some areas with very low GW recharge. G3M does not represent losing rivers in some dry regions. This study presents the first steps towards replacing the linear GW reservoir model in a GHM while improving on recent efforts, demonstrating the feasibility of the approach and the robustness of the newly developed framework.

scholarly journals Transient coarsening and the motility of optically heated Janus colloids in a binary liquid mixture

Soft Matter ◽  
2020 ◽  
Vol 16 (36) ◽  
pp. 8359-8371
Author(s):  
Juan Ruben Gomez-Solano ◽  
Sutapa Roy ◽  
Takeaki Araki ◽  
S. Dietrich ◽  
Anna Maciołek
Keyword(s):  
Steady State ◽  
Liquid Mixture ◽  
Binary Liquid Mixture ◽  
Binary Solvent ◽  
Janus Particle ◽  
Equilibrium Dynamics ◽  
Binary Liquid ◽  
Non Equilibrium

We study experimentally and theoretically the non-equilibrium dynamics of a binary solvent around a gold-capped Janus particle, lasting from the very moment of switching illumination on until a steady state is reached.

Steady-State Modelling and Simulation of a Reactive Distillation Process for n-Butyl Acetate Production Using CHEMCAD

2017 ◽  
Vol 29 ◽  
pp. 70-80 ◽  
Author(s):  
Abdulwahab Giwa ◽  
Saidat Olanipekun Giwa
Keyword(s):  
Acetic Acid ◽  
Steady State ◽  
Mole Fraction ◽  
Butyl Acetate ◽  
Reactive Distillation ◽  
Esterification Reaction ◽  
Reflux Ratio ◽  
Distillation Process ◽  
Condenser Section ◽  
Steady State Simulation

This work has been carried out to demonstrate the application of a process simulator known as CHEMCAD to the modelling and the simulation of a reactive distillation process used for the production of n-butyl acetate, with water as the by-product, from the esterification reaction between acetic acid and n-butanol. The esterification reaction, which is generally an equilibrium type, was modelled as two kinetic reaction types in the reaction section of the column used, which had 17 stages with the middle section (stages 6 – 12) being the reaction section. A reflux ratio of 3 and reboiler duty of 78 kJ/min as well as 30 mL/min of each of the reactants with 99% molar purity were used for the simulation of the column. The results obtained revealed that the developed model was a valid one because there was a very good agreement between the results and the theoretical knowledge of a distillation column based on the fact that the desired (which was the heavy) product (n-butyl acetate) was found to have the highest mole fraction in the bottom section of the column while the by-product of the process (water) was discovered to have a mole fraction higher than that of n-butyl acetate in the top (condenser) section of the column. Therefore, CHEMCAD has been applied to the steady-state simulation of the reactive distillation process used for the production of n-butyl acetate from the esterification reaction of acetic acid and n-butanol successfully.

Understanding the Optical Band Shape:  Coumarin-153 Steady-State Spectroscopy

2001 ◽  
Vol 105 (37) ◽  
pp. 8516-8532 ◽  
Author(s):  
Dmitry V. Matyushov ◽  
Marshall D. Newton
Keyword(s):  
Steady State ◽  
Band Shape ◽  
Coumarin 153

Thiocyanate as a probe of the cystic fibrosis transmembrane conductance regulator chloride channel pore

2001 ◽  
Vol 79 (7) ◽  
pp. 573-579 ◽  
Author(s):  
Paul Linsdell
Keyword(s):  
Cystic Fibrosis ◽  
Steady State ◽  
Mole Fraction ◽  
Chloride Channel ◽  
Theory Model ◽  
Anion Binding ◽  
Rate Theory ◽  
Patch Clamp Recording ◽  
Channel Pore ◽  
Mammalian Cell Lines

Immediately following exposure to thiocyanate (SCN–)-containing solutions, the cystic fibrosis conductance regulator Cl– channel exhibits high unitary SCN– conductance and anomalous mole fraction behaviour, suggesting the presence of multiple anion binding sites within the channel pore. However, under steady-state conditions SCN– conductance is very low. Here I show, using patch clamp recording from CFTR-transfected mammalian cell lines, that under steady-state conditions neither SCN– conductance nor SCN– permeability show anomalous mole fraction behaviour. Instead, SCN– conductance, permeability, and block of Cl– permeation can all be reproduced by a rate theory model that assumes only a single intrapore anion binding site. These results suggest that under steady-state conditions the interaction between SCN– and the CFTR channel pore can be understood by a simple model whereby SCN– ions enter the pore more easily than Cl–, and bind within the pore more tightly than Cl–. The implications of these findings for investigating and understanding the mechanism of anion permeation are discussed.Key words: chloride channel, permeation, anion binding, multi-ion pore behaviour, rate theory model.

scholarly journals Dissolution and solubility of the arsenate - phosphate hydroxylapatite solid solution [Ca5(PxAs1 - xO4)3(OH)] at 25°C

2011 ◽  
Vol 8 (2) ◽  
pp. 133 ◽  
Author(s):  
Xuehong Zhang ◽  
Yinian Zhu ◽  
Honghu Zeng ◽  
Dunqiu Wang ◽  
Jie Liu ◽  
...  
Keyword(s):  
Solid Solution ◽  
Aqueous Solution ◽  
Steady State ◽  
Mole Fraction ◽  
Large Family ◽  
Batch Experiments ◽  
Aqueous Environments ◽  
Phosphate Species ◽  
Peak Value

Environmental contextApatites form a large family of minerals and compounds that can incorporate a variety of ions, including arsenate that can substitute for phosphate. Apatites may therefore control the concentration of arsenic in some aqueous environments. This manuscript describes the synthesis and characterisation of the arsenate–phosphate hydroxylapatite solid solution and the solid solution–aqueous solution interaction. Abstract Nine different members of the arsenate–phosphate hydroxylapatite solid solution [Ca5(PxAs1–xO4)3(OH)] were prepared and characterised by various techniques, and then dissolution of the synthetic solids was studied at 25°C and pH 2 in a series of batch experiments. The concentrations of aqueous arsenate species increased rapidly at the beginning of the dissolution and reached a steady-state after 480 h. The concentrations of aqueous phosphate species increased very fast initially and reached a peak value within the first hour of dissolution and then declined slowly with time and remained constant after 240–360 h. The solubility of the Ca5(PxAs1–xO4)3(OH) solid solution increased and its stability decreased with an increase in the mole fraction of Ca5(AsO4)3(OH). The dissolution followed or slightly overshot the Lippmann solutus curve, then approached the solutus curve. The Ca5(AsO4)3(OH)-poor solid solution was in equilibrium with the arsenate-rich aqueous solution.

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