scholarly journals Investigation of Parameters Influencing Tubular-Shaped Chitosan-Hydroxyapatite Layer Electrodeposition

Molecules ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 104
Author(s):  
Mariusz Mąkiewicz ◽  
Radosław A. Wach ◽  
Katarzyna Nawrotek
Keyword(s):  
Calcium Ions ◽  
Structural Characteristics ◽  
Water Electrolysis ◽  
Nerve Tissue ◽  
Total Charge ◽  
Colloidal Systems ◽  
Colloidal Solutions ◽  
Time Deposit ◽  
Gas Volume ◽  
Calculated Number

Tubular-shaped layer electrodeposition from chitosan-hydroxyapatite colloidal solutions has found application in the field of regeneration or replacement of cylindrical tissues and organs, especially peripheral nerve tissue regeneration. Nevertheless, the quantitative and qualitative characterisation of this phenomenon has not been described. In this work, the colloidal systems are subjected to the action of an electric current initiated at different voltages. Parameters of the electrodeposition process (i.e., total charge exchanged, gas volume, and deposit thickness) are monitored over time. Deposit structures are investigated by scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). The value of voltage influences structural characteristics but not thickness of deposit for the process lasting at least 20 min. The calculated number of exchanged electrons for studied conditions suggests that the mechanism of deposit formation is governed not only by water electrolysis but also interactions between formed hydroxide ions and calcium ions coordinated by chitosan chains.

scholarly journals Effects of pipe casing structure on acoustic emission characteristics of underwater pyrotechnic combustion

2019 ◽  
Vol 39 (1) ◽  
pp. 149-157
Author(s):  
Jie Li ◽  
Jun Du ◽  
Xian Chen ◽  
Yanli Wang
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Acoustic Radiation ◽  
Structural Characteristics ◽  
Bubble Formation ◽  
Pressure Level ◽  
Radiation Characteristics ◽  
Acoustic Testing ◽  
Gas Volume ◽  
Broadband Sound

In order to investigate the acoustic radiation characteristics of underwater, a pipe casing was introduced and the effects of its main structural characteristics on underwater combustion acoustic radiation were studied by acoustic testing. The results show that the addition of the pipe casing significantly increased the sound pressure level of underwater pyrotechnic combustion, especially the peak of sound pressure level that was increased by 15.9 dB from 155.5 to 171.4 dB at the frequency of 125 and 100 Hz. But the addition of the pipe casing had little effect on the frequency. These results indicated that adding a pipe casing is effective for improving sound pressure level in underwater pyrotechnic combustion. An increase in nozzle diameter from 10 to 12.5 mm resulted in an increase of gas volume, so the peak of sound pressure level and broadband sound pressure level is higher. Changing the pipe casing direction to vertical downward will make the bubble formation period shorter, which will generate more bubbles and strong wake; the interaction between bubbles and wake results in a higher intensity of turbulence, which accounts for the coalescence and breakup of bubbles in the fluid. Besides, changing the diameter of pipe casing can be used to lower the frequency of underwater noise.

scholarly journals Investigations on the scattering of light in colloidal solutions and gels. Part I—Agar sol and gel

1929 ◽  
Vol 122 (789) ◽  
pp. 76-103 ◽  
Keyword(s):  
Optical Properties ◽  
Colloidal Particles ◽  
Clear Understanding ◽  
Special Importance ◽  
Colloidal Systems ◽  
Colloidal Solutions ◽  
Scattering Of Light ◽  
Internal Equilibrium ◽  
Tyndall Effect ◽  
Colloidal State

One of the fundamental problems in the field of colloids is the investigation of their structure. This is a subject of considerable importance and has been attracting a great deal of attention from workers in this field. A systematic study of the various physical properties of colloids is essential for a clear understanding of the nature of the colloidal state. The optical properties are of special importance as they have the great advantage of revealing the structure of colloidal systems without disturbing their internal equilibrium. They furnish direct information concerning the size and the shape of the colloidal particles. In a series of papers, of which this is the first, the author proposes to publish investigations on the scattering of light in colloidal solutions and gels. An attempt will be made to discuss the various problems concerning their structure, as revealed by the study of the Tyndall effect in such systems.

scholarly journals The properties of colloidal systems. I.-The osmotic pressure of congo-red and of some other dyes

1909 ◽  
Vol 81 (548) ◽  
pp. 269-286 ◽  
Keyword(s):  
Blood Serum ◽  
Osmotic Pressure ◽  
Congo Red ◽  
Colloidal Systems ◽  
Colloidal Solutions ◽  
Definite Proof ◽  
Made In

Experiment made in 1895 by Linder and Picton upon solutions of arsenious sulphide indicated that colloidal solutions possess a real osmotic pressure, although the authors themselves claim no quantitative value for their results. In 1905 further experiments were made, but again great difficulties were met with, and, although it seemed evident that osmotic pressure was present, the numerical values obtained were irregular and small. The first definite proof that certain colloidal solutions are able to exert a not inconsiderable osmotic pressure was given by Starling in the case of the colloids of blood-serum. When separated by a gelatin membrane from a solution obtained by filtration of some of the same serum through Martin’s gelatin filter, the pressure rose to about 30 mm. Of mercury.

scholarly journals STUDY OF CHITOSAN PROTECTIVE PROPETIES IN COLLOIDAL SOLUTIONS OF CADMIUM SELENIDE QUANTUM DOTS

2017 ◽  
pp. 217-223
Author(s):  
Ирина (Irina) Андреевна (Andreevna) Штоббе (Shtobbe) ◽  
Сергей (Sergej) Александрович (Aleksandrovich) Безносюк (Beznosjuk) ◽  
Ирина (Irina) Евгеньевна (Evgen'evna) Мозорева (Mozoreva)
Keyword(s):  
Quantum Dots ◽  
Protective Effect ◽  
Cadmium Selenide ◽  
Light Transmission ◽  
Protective Action ◽  
Colloidal System ◽  
Colloidal Systems ◽  
Colloidal Solutions ◽  
Chitosan Matrix ◽  
Cadmium Selenide Quantum Dots

In this paper, by a low-temperature colloidal aqueous method, without the use of toxic media, the quantum dots of cadmium selenide in the shell of chitosan were synthesized. Chitosan was used as a matrix for the growth of colloidal semiconductor particles, and it also stabilized the obtained particles.The purpose of this work was studying the protective properties of chitosan in colloidal solutions of cadmium selenide quantum dots. The objective of the study was to analyze the protective effect of chitosan in colloidal systems by analyzing the optical and rheological properties of the obtained solutions.The dependence of the light transmission of colloidal solutions of cadmium selenide quantum dots in the shell of chitosan on the concentration of polysaccharide was investigated.It has been established that the light transmission of colloidal solutions decreases with time, the lower the content of chitosan in solution, which indicates that the protective action of colloidal solutions of quantum dots of cadmium selenide increases with increasing concentration of the polysaccharide.A study was made of the kinematic viscosity of the obtained solutions with different concentrations of chitosan in time. It was established that when the quantum dots are formed in the chitosan matrix, the viscosity of the colloidal system decreases. The protective effect of chitosan increases with increasing concentration in the solution.

scholarly journals Quantitative express estimation of humine and fulvo acids content in aqueous solutions by photo-stimulated luminescence

2018 ◽  
Keyword(s):  
Quantum Yield ◽  
Dynamic Range ◽  
Light Flux ◽  
Low Noise ◽  
Light Sources ◽  
Colloidal Systems ◽  
Colloidal Solutions ◽  
Measuring Device ◽  
Light Emitting ◽  
Quantum Yield Of Luminescence

The work substantiates the expediency of using the methods of recording the quantum yield of luminescence of humic and folic compounds in the process of determining the relative concentrations of these substances in aqueous and colloidal solutions. The efficiency of using modern high-power ultraviolet semiconductor light sources with high monochromaticity of light flux has been proved, followed by the registration of reviews of the samples under investigation with the help of a low-noise semiconductor photodetector with a connected operational amplifier, which allows to provide a wide dynamic range of current and voltage measurements. The subject of the study is the process of recording the quantitative and qualitative parameters of the se- lected chemical compounds in colloidal systems in the liquid phase developed in the course of research by the model of the measuring instrument. The novelty of the work is to improve the classical methods for recording the quantum yield of lumines- cence, using a modern element base and testing the model of a measuring device with powerful ultraviolet light-emitting diodes as a light source and low-noise photodetector with a clear dynamic range designed for recording the quantum yield of luminescence of the samples under investigation.

scholarly journals Injectable Chitosan Scaffolds with Calcium β-Glycerophosphate as the Only Neutralizing Agent

Processes ◽  
2019 ◽  
Vol 7 (5) ◽  
pp. 297 ◽  
Author(s):  
Piotr Owczarz ◽  
Anna Rył ◽  
Marek Dziubiński ◽  
Jan Sielski
Keyword(s):  
Calcium Ions ◽  
Sol Gel ◽  
Sem Analysis ◽  
Sodium Ions ◽  
Colloidal Solutions ◽  
Crosslinking Process ◽  
Chitosan Scaffolds ◽  
Neutralizing Agent ◽  
Gel Phase ◽  
Chitosan Hydrogels

The presented work describes the method of preparation of thermosensitive chitosan hydrogels using calcium β-glycerophosphate salt as the only pH neutralizing agent and supporting the crosslinking process. The presence of calcium ions instead of sodium ions is particularly important in the case of scaffolds in bone tissue engineering. Rheological and physicochemical properties of low concentrated chitosan solutions with the addition of calcium β-glycerophosphate were investigated using rotational rheometry techniques, Zeta potential (by electrophoresis), XPS, and SEM analysis together with an EDS detector. It was found to be possible to prepare colloidal solutions of chitosan containing only calcium β-glycerophosphate (without sodium ions) undergoing a sol-gel phase transition at the physiological temperature of the human body. It has also been shown that it is possible to further enrich the obtained cellular scaffolds with calcium ions. Using the addition of calcium carbonate, hydrogels with a physiological ratio of calcium to phosphorus (1.6–1.8):1 were obtained.

scholarly journals Sepiolite-Hydrogels: Synthesis by Ultrasound Irradiation and Their Use for the Preparation of Functional Clay-Based Nanoarchitectured Materials

2021 ◽  
Vol 9 ◽  
Author(s):  
Eduardo Ruiz-Hitzky ◽  
Cristina Ruiz-García ◽  
Francisco M. Fernandes ◽  
Giulia Lo Dico ◽  
Lorenzo Lisuzzo ◽  
...  
Keyword(s):  
Layered Double Hydroxides ◽  
High Speed ◽  
Structural Characteristics ◽  
Functional Materials ◽  
Ultrasound Irradiation ◽  
High Viscosity ◽  
Low Density ◽  
Colloidal Systems ◽  
Micro Particles ◽  
Double Hydroxides

Sepiolite and palygorskite fibrous clay minerals are 1D silicates featuring unique textural and structural characteristics useful in diverse applications, and in particular as rheological additives. Here we report on the ability of grinded sepiolite to generate highly viscous and stable hydrogels by sonomechanical irradiation (ultrasounds). Adequate drying of such hydrogels leads to low-density xerogels that show extensive fiber disaggregation compared to the starting sepiolite—whose fibers are agglomerated as bundles. Upon re-dispersion in water under high-speed shear, these xerogels show comparable rheological properties to commercially available defibrillated sepiolite products, resulting in high viscosity hydrogels that minimize syneresis. These colloidal systems are thus very interesting as they can be used to stabilize many diverse compounds as well as nano-/micro-particles, leading to the production of a large variety of composites and nano/micro-architectured solids. In this context, we report here various examples showing how colloidal routes based on sepiolite hydrogels can be used to obtain new heterostructured functional materials, based on their assembly to solids of diverse topology and composition such as 2D and 1D kaolinite and halloysite aluminosilicates, as well as to the 2D synthetic Mg,Al-layered double hydroxides (LDH).

scholarly journals The distribution of suspended particles under gravity

1932 ◽  
Vol 138 (834) ◽  
pp. 133-146 ◽  
Keyword(s):  
Volume Concentration ◽  
Colloidal Suspensions ◽  
Coarse Particles ◽  
Colloidal Systems ◽  
Colloidal Solutions ◽  
Large Particles ◽  
Apparent Stability ◽  
Gravitational Equilibrium ◽  
Number Of Particles ◽  
Numerical Concentration

The apparent stability and freedom from settling shown in practice by many colloidal suspensions has in recent years prompted renewed study of the distribution of the particles of colloidal systems under the influence of gravity, and results greatly at variance with earlier work have been obtained. The object of the present communication is (1) to show that the later conclusions are not justified by the experiments on which they are based, and (2) to describe experiments which favour a considerable extension of the applicability to colloidal solutions of a law similar to that which defines the behaviour of ordinary dilute solutions. Perrin, in 1909, showed that there was, within a depth of 0·01 cm. from the surface, a logarithmic decrease of concentration with height for suspensions of gamboge or mastic in gravitational equilibrium. In 1914 Costantin, working at lower depths than Perrin, and with a higher volume concentration of gamboge and correspondingly higher numerical concentration, obtained evidence of a repelling force between the particles at concentrations greater than 8 X 10 10 particles per cubic centimetre. Perrin showed how his equation could be modified to take this into account by assuming a law of the van der Waals’ type, which was found to agree with the observations up to the highest concentration investigated (6 X 10 11 particles per cubic centimetre). In the following year Westgren published the results of a series of measurements on selenium and gold sols with coarse particles, which were in complete harmony with Perrin’s law over a distance of 0·05 cm. and at concentrations up to 5 X 10 10 per cubic centimetre. These investigators were precluded from studying the distribution over greater ranges of depth solely by the restrictions of their experimental method, which demanded that for accurate counting the number of particles in the field of view should not be too large. For this reason also they were limited to moderately dilute sols and to rather large particles, that is, to specially prepared sols.

scholarly journals Digital sovereignty of Russia based on the element base of topological nanostructures on a solid surface induced by laser radiation

2021 ◽  
Vol 2131 (5) ◽  
pp. 052082
Author(s):  
S M Arakelian ◽  
A O Kucherik ◽  
D N Bukharov ◽  
T A Khudaiberganov
Keyword(s):  
Solid Surface ◽  
Materials Science ◽  
Structural Characteristics ◽  
High Tech ◽  
State University ◽  
Colloidal Systems ◽  
Industrial Sectors ◽  
Stage Scheme ◽  
Surface Nanostructures ◽  
Technical Principles

Abstract The purpose of this work is to develop breakthrough technologies and technology transfer in the field of topological photonics, nanoelectronics and new materials with controlled functional and structural characteristics using a unique line of the Vladimir State University (VlSU) equipment (within the framework of the corresponding created structures - Centre of collective use, Center for Structural Materials Science and Breakthrough Engineering Physical Technologies, Center for Engineering Competencies, etc.) for carrying out work in the direction of high-tech industrial sectors. The report deals with the following issues on this topic: basic physical and scientific and technical principles, methods for measuring laser-induced structures on the surface of materials in real time, obtaining surface nanostructures on solid materials by deposition from colloidal systems using a two-stage scheme with laser ablation, modeling macroscopic quantum states in the functional properties of laser-induced 4d-topological nanoclusters in thin films on a solid surface and experimental demonstration of the work of real prototypes.

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