scholarly journals Nature of Excess Hydrated Proton at the Water–Air Interface

2019 ◽  
Vol 142 (2) ◽  
pp. 945-952 ◽  
Author(s):  
Sudipta Das ◽  
Sho Imoto ◽  
Shumei Sun ◽  
Yuki Nagata ◽  
Ellen H. G. Backus ◽  
...  
Keyword(s):  
Air Interface ◽  
Hydrated Proton

FRACTALIZATION OF CONVECTIVE FLOW UPON VERTICAL GROOVED DISC/AIR INTERFACE

2020 ◽  
Vol 27 (3) ◽  
pp. 267-288
Author(s):  
Tahar Boussoukaia ◽  
Belkacem Draoui ◽  
M. Hamouda
Keyword(s):  
Convective Flow ◽  
Air Interface

SIMULASI NEURAL NETWORK UNTUK PREDIKSI LOKASI USER PADA MOBILE NETWORK

2016 ◽  
Vol 9 (1) ◽  
Author(s):  
Alexander Driyarkoro ◽  
Nurain Silalahi ◽  
Joko Haryatno
Keyword(s):  
Neural Network ◽  
Mobile Station ◽  
Mobile Network ◽  
Learning Rate ◽  
Noise Factor ◽  
Optimal Learning ◽  
Air Interface ◽  
Location Area ◽  
Optimal Learning Rate

Prediksi lokasi user pada mobile network merupakan hal sangat penting, karena routing panggilan pada mobile station (MS) bergantung pada posisi MS saat itu. Mobilitas MS yang cukup tinggi, terutama di daerah perkotaan, menyebabkan pencarian (tracking) MS akan berpengaruh pada kinerja sistem mobile network, khususnya dalam hal efisiensi kanal kontrol pada air interface. Salah satu bentuk pencarian adalah dengan mengetahui perilaku gerakan yang menentukan posisi MS. Dari MSC/VLR dapat diketahui posisi MS pada waktu tertentu. Karena location area suatu MS selalu unik dari waktu ke waktu, dan hal itu merupakan perilaku (behaviour) MS, maka dapat dibuat profil pergerakannya. Dengan menggunakan Neural Network (NN) akan diperoleh location area MS pada masa yang akan datang. Model NN yang digunakan pada penelitian ini adalah Propagasi Balik. Beberapa parameter NN yang diteliti dalam mempengaruhi kinerja prediksi lokasi user meliputi noise factor, momentum dan learning rate. Pada penelitian ini diperoleh nilai optimal learning rate = 0,5 dan noise factor = 1.

scholarly journals Interfacial Crystallization and Supramolecular Self-Assembly of Spider Silk Inspired Protein at the Water-Air Interface

Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4239
Author(s):  
Pezhman Mohammadi ◽  
Fabian Zemke ◽  
Wolfgang Wagermaier ◽  
Markus B. Linder
Keyword(s):  
Self Assembly ◽  
Spider Silk ◽  
Assembly Process ◽  
Protein Solution ◽  
Time Resolved ◽  
Macromolecular Assembly ◽  
X Ray Scattering ◽  
Air Interface ◽  
Fundamental Research ◽  
Β Sheet

Macromolecular assembly into complex morphologies and architectural shapes is an area of fundamental research and technological innovation. In this work, we investigate the self-assembly process of recombinantly produced protein inspired by spider silk (spidroin). To elucidate the first steps of the assembly process, we examined highly concentrated and viscous pendant droplets of this protein in air. We show how the protein self-assembles and crystallizes at the water–air interface into a relatively thick and highly elastic skin. Using time-resolved in situ synchrotron X-ray scattering measurements during the drying process, we showed that the skin evolved to contain a high β-sheet amount over time. We also found that β-sheet formation strongly depended on protein concentration and relative humidity. These had a strong influence not only on the amount, but also on the ordering of these structures during the β-sheet formation process. We also showed how the skin around pendant droplets can serve as a reservoir for attaining liquid–liquid phase separation and coacervation from the dilute protein solution. Essentially, this study shows a new assembly route which could be optimized for the synthesis of new materials from a dilute protein solution and determine the properties of the final products.

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

Molecules ◽  
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.

Marangoni-flow-induced partial coalescence of a droplet on a liquid/air interface

2018 ◽  
Vol 3 (2) ◽  
Author(s):  
Kai Sun ◽  
Peng Zhang ◽  
Zhizhao Che ◽  
Tianyou Wang
Keyword(s):  
Marangoni Flow ◽  
Partial Coalescence ◽  
Air Interface

scholarly journals β-Lactoglobulin Adsorption Layers at the Water/Air Surface: 5. Adsorption Isotherm and Equation of State Revisited, Impact of pH

2021 ◽  
Vol 5 (1) ◽  
pp. 14
Author(s):  
Georgi G. Gochev ◽  
Volodymyr I. Kovalchuk ◽  
Eugene V. Aksenenko ◽  
Valentin B. Fainerman ◽  
Reinhard Miller
Keyword(s):  
Theoretical Description ◽  
Fluid Interfaces ◽  
Interfacial Behavior ◽  
Current State ◽  
Air Interface ◽  
Direct Measurements ◽  
Wide Range ◽  
Dilational Viscoelasticity ◽  
Parameter Values ◽  
Β Lactoglobulin

The theoretical description of the adsorption of proteins at liquid/fluid interfaces suffers from the inapplicability of classical formalisms, which soundly calls for the development of more complicated adsorption models. A Frumkin-type thermodynamic 2-d solution model that accounts for nonidealities of interface enthalpy and entropy was proposed about two decades ago and has been continuously developed in the course of comparisons with experimental data. In a previous paper we investigated the adsorption of the globular protein β-lactoglobulin at the water/air interface and used such a model to analyze the experimental isotherms of the surface pressure, Π(c), and the frequency-, f-, dependent surface dilational viscoelasticity modulus, E(c)f, in a wide range of protein concentrations, c, and at pH 7. However, the best fit between theory and experiment proposed in that paper appeared incompatible with new data on the surface excess, Γ, obtained from direct measurements with neutron reflectometry. Therefore, in this work, the same model is simultaneously applied to a larger set of experimental dependences, e.g., Π(c), Γ(c), E(Π)f, etc., with E-values measured strictly in the linear viscoelasticity regime. Despite this ambitious complication, a best global fit was elaborated using a single set of parameter values, which well describes all experimental dependencies, thus corroborating the validity of the chosen thermodynamic model. Furthermore, we applied the model in the same manner to experimental results obtained at pH 3 and pH 5 in order to explain the well-pronounced effect of pH on the interfacial behavior of β-lactoglobulin. The results revealed that the propensity of β-lactoglobulin globules to unfold upon adsorption and stretch at the interface decreases in the order pH 3 > pH 7 > pH 5, i.e., with decreasing protein net charge. Finally, we discuss advantages and limitations in the current state of the model.

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