Adiabatic Compressibility Coefficient Research Articles

БИОЛОГИЯЛЫҚ СҮТ ӨНІМДЕРІН СЕРПІМДІ ТОЛҚЫНДАРМЕН ЗЕРТТЕУ

The scientific article contains a pulsed ultrasonic installation in order to determine the temperature dependence of the density of biological fluids and the velocity of their elastic linear wave and the coefficient of adiabatic compressibility. With the help of experimental measurements and theoretical calculations, the temperature dependences of the density of the sample under study, the velocity of the linear wave, the coefficient of adiabatic compressibility (25-125)0C were studied for the first time, graphs of the dependences p=p(t), u=u(t), α5= α5 (t) were constructed. In order to study biological fluids, we used a thermos for domestic use. The source and receiver of the ultrasonic wave, a mirror reflecting the wave, a heater, and injection molding machines are placed in the biological liquid under study. We have positioned the piezoelectric element and the mirror at a certain distance. The required temperature and velocity of the elastic wave in the studied samples were measured using special curves a and B. Correct measurements of the installation.

Molecular Interaction Study in the Binary Liquid Mixture of PEO and DMF by Ultrasonic Technique

The non‐destructive ultrasonic technique is a great employ for knowing the solute–solvent interaction in the polymer blend. By the ultrasonic velocity and attenuation evaluation, the visco‐elastic behaviors of the polymer solution have been assessed and compared with the results of conventional dynamic mechanical analysis. In the present research work, a comprehensive ultrasonic investigation of molecular interaction in a polymeric mixture of Poly (ethylene oxide) PEO and dimethyformamide (DMF) at 333 K has been executed by using the information provided by the literature. For this purpose, ultrasonic waves of two different frequencies such as 2 and 5 MHz have been implemented. Several acoustical parameters such as adiabatic compressibility, acoustic impedance, relaxation time, and ultrasonic attenuation coefficient (𝛼/𝑓2) are explored. Thermodynamic parameters like relative association and intermolecular free path length are also estimated. The evaluated values have been associated with the previous experimental results. The non‐ideal approach of the solution is analyzed and discussed in detail.

Modeling of water hammer effect during the single cavitating bubble oscillation

The paper presents the results of an analytical study of the vapor-gas bubble dynamics in cavitation processes, giving consideration to the liquid compressibility. The study is based on the concept that cavitation effects are directly related to the occurrence of hydraulic shock on the surface of an extremely compressed bubble. The purpose of this work is to study cavitation bubble dynamics accounting for the spherical water hammer effects. An equation for the bubble dynamics was obtained, which includes the coefficient of liquid adiabatic compressibility as a basic parameter that is directly related to the liquid compressibility. For this equation reduces to the classical Rayleigh-Plesset equation for incompressible liquids. The results of a computational experiment performed within the framework of the modified model are presented for which the behavior of a cavitation bubble both in compressible and in incompressible water was analyzed. Based on a detailed analysis of the results obtained, it is shown that over time .the compressed bubble is in the state of a supercritical fluid with temperature up to 2000 K and pressure of about 400 MPa. The potential energy of the compressed liquid, in the form of a powerful acoustic pulse, emitted by the bubble at the stage of its collapse, is irreversibly dissipated in the surrounding liquid.

GREEN SYNTHESIS OF CHROMIUM OXIDE NANOPARTICLES - STUDY OF ITS ANTIBACTERIAL, PHOTOCATALYTIC AND THERMODYNAMIC PROPERTIES

An endeavor has been made to report the herbal synthesis of chromium oxide (Cr2O3) nanoparticles using aqueous extract of nigella sativa seed extract as a capping agent and chromic sulphateas a precursor material. The structural, morphological and optical properties of the Cr2O3 nanoparticles were analyzed by X - ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and UV- Visible spectroscopy. The antibacterial efficacy of chromium oxide nanoparticles was tested against Staphylococcus aureus, Klebsiella pneumonia and Pseudomonas aeruginosa. The photocatalytic activity of biosynthesized Cr2O3 nanoparticles was evaluated by degrading methylene blue dye and Congo red dye under the irradiation of visible light. Apart from this, ultrasonic velocity, density and viscosity were measured for different concentrations of Cr2O3 nanofluid using ultrasonic techniques. Thermoacoustical such as adiabatic compressibility, free length, acoustic impedance, relaxation time and absorption coefficient values are computed from the measured data and the results are interpreted in terms of particle - fluid interactions.

Prediction of sound velocity for selected ionic liquids using a multilayer feed-forward neural network

Ionic liquids (ILs) have a great potential as the new hydraulic fluids and the high-pressure heat transfer media. The speed of sound data represent the basis for determining practically important thermoelastic and thermodynamic properties. Since the speed of sound velocity measurements at elevated pressures are expensive and time consuming, their accurate predictions become particularly valuable. This study proposes a structurally straightforward neural network for speed of sound and adiabatic compressibility data in ILs. Its results are compared with the predictions of CP-PC-SAFT Equation of State. It is shown that both models are accurate, while each of them has advantages and disadvantages. Predictions of the adiabatic compressibility coefficients by CP-PC-SAFT and modelling framework coupling CP-PC-SAFT and neural network are also discussed.

Characterization of the ergometric properties of commercial bioactive dairy peptides

The thermodynamic properties of bioactive peptides provide insights into their functional behavior and their biological efficacy. We conducted precise analyses of the density, the ultrasonic velocity and the relative attenuation of serial dilutions of three commercial dairy peptides prepared by enzymatic methods. From these we determined the partial specific volume and the partial specific adiabatic compressibility coefficient for the peptides. At concentrations greater than ~2.5 ​mg ​mL−1, the apparent values for specific volume and adiabatic compressibility were constant, differing between the three peptides at ±3% for specific volume and ±70% for compressibility. Both specific volume and adiabatic compressibility were highly dependent on concentration, indicating the importance of precise low concentration measurements to obtain correct values for these thermodynamic parameters. From these parameters it was apparent that restructuring of water molecules around the peptides (and their associated counterions) led to compact solutes that were also incompressible. These thermodynamic analyses are critical for understanding how the properties and the beneficial effects of bioactive peptides are influenced by their chemical environment.

Molecular interactions analysis of some aluminium salts in binary aqueous solutions of tetrahydrofuran (THF): Acoustic and Conductometric approach

In the present investigation conductance and speed of sound of aluminium sulphate, aluminium nitrate, and aluminium chloride were experimentally determined in aqueous medium as well in binary aqueous mixtures of THF. Various conductance and acoustic parameters viz; molar conductance, limiting molar conductance, partial molar adiabatic compressibility, coefficient of adiabatic compressibility were also determined using Kohlrausch's Law, Debye-Huckel theory and Masson’s equation at working temperatures and different compositions of THF. Analysis reveals that limiting molar conductivity decreases with increase in composition of THF in water indicating the decrease in the ion-solvent interactions with increase in composition THF in water. Further it was found that with increase in temperature the values increase for all the three salts which support the increase in ion-solvent interactions with increase in temperature. The values of partial molar isentropic compression were found negative and these values further increase with increase in composition of THF indicating that on increase in composition, attractive interactions develop between THF and water which induces dehydration of aluminium salts which make the water molecules of aluminium salts more compressible than that of lower THF concentration resulting in decrease of ion solvent interactions with increase in THF composition in water. On the other hand with increase in temperature, the values of further increase leading to increase in ion-solvent interactions of aluminium salts in water and 5% THF+ water. Walden product and its temperature coefficient i.e. have also been calculated which confirms that aluminium salts act as structure breaker in different compositions of THF in water.

Fractionation of Acacia seyal gum by ion exchange chromatography

Acacia gum is a complex gum exudate from trees of selected Acacia species (i.e. A. senegal and A. seyal). It is a continuum of molecular species showing diverse, sugar and protein composition, molar mass and charge density. Numerous studies have been conducted on several aspects of Acacia senegal gum (Asen), including its fractionation. Acacia seyal gum (Asey) has been less studied, although it has recently been gaining importance. Certain gum characteristics, such as the protein and polysaccharide composition and the molecular parameters, play a key role in the Acacia gums functionality and, hence, in their uses by food, pharmaceutical or materials industries. Our main objective is to obtain a fraction from Asey gum with high molar mass and high protein content, allowing future research works and industrial applications. Asey gum has been separated by ion exchange chromatography (IEC) into two different fractions, IEC-F1 and IEC-F2, which have been thoroughly characterized. Thus, we have succeeded to recover a protein-rich fraction with high molar mass and high intrinsic viscosity, the fraction IEC-F1. The Mark-Houwink-Sakurada analysis further indicated that fraction IEC-F1 presents more anisotropic conformation compared to fraction IEC-F2. From the partial specific volume (vs°) and the partial specific adiabatic compressibility (βs°) coefficients, a more flexible and less hydrated structure in the fraction IEC-F1 compared to Asey gum was suggested.

Tetraalkylammonium bromide-water mixtures revisited: Isothermal compressibility and internal pressure variation in limiting concentration range at 298.15 K

Abstract The recent literature data of density (ρ) at different temperatures (293.15, 298.15 and 303.15 K) and sound velocity (u) at 298.15 K on aqueous solutions of tetraalkylammonium bromides (R4NBr) in limiting concentration range (0.01–0.15) mol kg−1 have been used to obtain coefficient of thermal expansion (α) and adiabatic compressibility (βs) of solutions at 298.15 K. Using specific heat capacity (Cp) data, the appropriate calculations of isothermal compressibility (βT) and internal pressure (Pi) in solutions have been accomplished. In solutions the Pi and βs were found to increase and decrease with increase in concentration of salt. These have been interpreted in terms of hydrophobic hydration of R4N+ cations in contrast to normal alkali cation hydration. The Tammann-Tait-Gibson (TTG) model was applied to derive the excess volume change for the electrolytes ( V ‾ 2 0 E = V ‾ 2 - V int . ) and intrinsic volume (Vint.) of the studied salts at 298.15 K. The Vint. values are further used to compute ionic radii for tetraalkylammonium cations (R4N+) by subtracting the intrinsic volume of bromide ions. The calculated radii agree satisfactorily with those obtained from model and geometry consideration of cations. The magnitudes of excess volumes are found to be negative and which increase with the extent of methylene group substitution (tetramethyl to tetrabutyl cations) in the salt cations. This is generally known as water structural and caging effect. The analysis of the present work indicates that the thermal expansion coefficient property of the organic cations and water structural alterations (in the form of clathrate like structures), govern the parameters like excess volumes of the ions in contrast to normal electrostrictive alkali cations. The results are in conformity of the Frank and Wen’s model of hydration of cations mainly governed by cation-cation interaction presumably due to the overlapping of extensive hydration structures and not directly caused by columbic hydration.

Flexibility and Hydration of Amphiphilic Hyperbranched Arabinogalactan-Protein from Plant Exudate: A Volumetric Perspective

Plant Acacia gum exudates are composed by glycosylated hydroxyproline-rich proteins, which have a high proportion of heavily branched neutral and charged sugars in the polysaccharide moiety. These hyperbranched arabinogalactan-proteins (AGP) display a complexity arising from its composition, architecture, and conformation, but also from its polydispersity and capacity to form supramolecular assemblies. Flexibility and hydration partly determined colloidal and interfacial properties of AGPs. In the present article, these parameters were estimated based on measurements of density and sound velocity and the determination of volumetric parameters, e.g., partial specific volume (vs°) and coefficient of partial specific adiabatic compressibility coefficient (βs°). Measurements were done with Acacia senegal, Acacia seyal, and fractions from the former separated according to their hydrophobicity by Hydrophobic Interaction Chromatography, i.e., HIC-F1, HIC-F2, and HIC-F3. Both gums presented close values of vs° and βs°. However, data on fractions suggested a less hydrated and more flexible structure of HIC-F3, in contrast to a less flexible and more hydrated structure of HIC-F2, and especially HIC-F1. The differences between the macromolecular fractions of A. senegal are significantly related to the fraction composition, protein/polysaccharide ratio, and type of amino acids and sugars, with a polysaccharide moiety mainly contributing to the global hydrophilicity and a protein part mainly contributing to the global hydrophobicity. These properties form the basis of hydration ability and flexibility of hyperbranched AGP from Acacia gums.

Speed of sound and density of water + 1,5-pentanediol mixtures in a wide temperature range. Comparison with mixtures of water with diethylene glycol, propoxyethanol and diethylene glycol dimethyl ether

Densities (ρ) and speed of sound (u) were measured in the binary liquid mixture of water and 1,5-pentanediol (PD) over the entire mixture composition range. Densitometric measurement were conducted in a temperature range of 278.15–333.15K under atmospheric pressure, using a precise sealed vibrating-tube densimeter. Acoustic study was carried out in a range of 288.15–318.15K. The values of molar volume (Vm), adiabatic compressibility coefficient (βs), temperature coefficients of these parameters, excess of compressibility coefficient (βsE), excess molar volume (VmE) and derivatives (∂H/∂p), (∂S/∂p) and (∂Cp/∂p) were determined from the experimental data. The values of molar volume were used to determine the values of partial molar volumes of the mixture components. Changes in the measured and calculated values of the physicochemical parameters as a function of temperature and composition of the mixture were analysed in terms of interactions in two-component systems. The obtained results were compared with those received in our earlier investigations of the mixtures of water with diethylene glycol and propoxyethanol as well as with those found in the literature survey concerning water–diethylene glycol dimethyl ether mixtures.

Acoustic and volumetric studies on water + diethylene glycol mixtures in a wide temperature range. Comparison with mixtures of water with tri- and tetraethylene glycol

Densities (ρ) and sound velocity (u) were measured in the binary liquid mixture of water and diethylene glycol-water (DEG) over the entire mixture composition range. Density values were recorded in a temperature range of 278.15–333.15K under atmospheric pressure, using a precise sealed vibrating-tube densimeter. Sound speed values were recorded in a range of 288.15–318.15K. The values of molar volume (Vm), adiabatic compressibility coefficient (βs), temperature coefficients of these parameters, excess of compressibility coefficient (βsE), excess molar volume (VmE) and derivatives (∂H/∂p), (∂S/∂p) and (∂Cp/∂p) were determined from the experimental data.The values of molar volume were used to determine the values of partial molar volumes of the mixture components. Changes in the values of physicochemical parameters measured and calculated as functions of composition and temperature were analyzed in the aspect of intermolecular interactions in two-component systems. The results obtained were compared with the results of similar studies of the mixtures of water and tri- and tetraethylene glycols.

Acoustic and volumetric studies on (triethylene glycol + water) mixtures in a wide temperature range

The sound velocity (u) and density (ρ) have been measured in binary liquid mixture of water and (triethylene glycol+water) (TEG) over the entire mixture composition range. Density values were recorded in a temperature range of (278.15 to 333.15)K, while speed of sound values were recorded in a range of T=(288.15 to 318.15)K. The values of molar volume (Vm), adiabatic compressibility coefficient (βs), temperature coefficients of these parameters, excess of compressibility coefficient (βsE), excess molar volume (VmE) and derivatives (∂H/∂p), (∂S/∂p) and (∂Cp/∂p) have been determined from the experimental data.The values of molar volume were used to determine the values of partial molar volumes of the mixture components. Changes in the values of physicochemical parameters measured and calculated as functions of composition and temperature were analysed in the aspect of intermolecular interactions in two-component systems.

Volumetric and acoustic studies on (tetraethylene glycol + water) mixtures in a wide temperature range

The sound velocity (u) and density (ρ) of (tetraethylene glycol (T4EG)+water) mixtures were measured in the whole mixture composition range. Density measurements were carried out in the temperature range of (278.15 to 333.15)K, while acoustic measurements in the temperature range of (288.15 to 318.15)K. Density and sound velocity values were used to determine the values of molar volume (Vm), adiabatic compressibility coefficient (βs) as well as temperature coefficients of these parameters. The values of excess compressibility coefficient (βsE), excess molar volume (VmE), excess expansion volume coefficient (αE) and derivatives (∂H/∂p), (∂S/∂p) and (∂Cp/∂p) were also determined. The partial molar volumes of the mixture components were calculated. Changes in the measured and calculated values of physicochemical parameters as functions of composition and temperature were analysed in terms of interactions and structure of the binary mixtures investigated.

Acoustic and Volumetric Properties of Binary Mixtures of Ionic Liquid 1-Butyl-3-methylimidazolium Bis(trifluoromethylsulfonyl)imide with Acetonitrile and Tetrahydrofuran

Speeds of sound and densities of binary mixtures of 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide with acetonitrile or with tetrahydrofuran have been measured within the temperature range of (298.15 to 313.15) K. From these experimental values, some related quantities have been derived, such as adiabatic compressibility coefficients, κs, excess molar volumes, VE, excess molar compressions, KSE, apparent molar volumes, Vϕ, partial molar volumes, Vi, excess partial molar volumes, ViE, and apparent molar adiabatic compressions, KS,ϕ. It has been found that concentration dependence of speed of sound in investigated systems resembles that of surface tension. Also, it has been observed that excess molar volumes and adiabatic compressions of some shorter chain 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imides in mixtures with the same solvent are very similar.

Ultrasonic and densimetric titration applied for acid-base reactions.

Classical acoustic acid-base titration was monitored using sound speed and density measurements. Plots of these parameters, as well as of the adiabatic compressibility coefficient calculated from them, exhibit changes with the volume of added titrant. Compressibility changes can be explained and quantitatively predicted theoretically in terms of Pasynski theory of non-compressible hydrates combined with that of the additivity of the hydration numbers with the amount and type of ions and molecules present in solution. It also seems that this development could be applied in chemical engineering for monitoring the course of chemical processes, since the applied experimental methods can be carried out almost independently on the medium under test (harmful, aggressive, etc.).

Ultrasonic and Densimetric Characterization of the Association of Cyclic AMP with the cAMP-Binding Domain of the Exchange Protein EPAC1

We employed a combination of densimetric and ultrasonic velocimetric techniques to characterize the volumetric properties of the association of the cAMP-binding domain (CBD) of EPAC1 with cAMP at 25 °C in a pH 7.6 buffer. The binding of cAMP to the CBD of EPAC1 is accompanied by changes in volume, ΔV, and adiabatic compressibility, ΔKS, of -59 ± 4 cm(3) mol(-1) and (34 ± 9) × 10(-4) cm(3) mol(-1) bar(-1), respectively. We use these volumetric results in conjunction with the structural data to estimate a change in hydration, Δnh, accompanying the binding. We calculate that approximately 103 water molecules are released to the bulk from the associating surfaces of the protein and the ligand. This number is ∼30% larger than the number of water molecules in direct contact with the associating surfaces while also being within the error of our Δnh determination. Therefore, we conclude that cAMP binding to EPAC1 may involve, in addition to the waters from within the first coordination sphere, also some waters from the second coordination sphere of the protein and cAMP. Our analysis of the compressibility data reveals that the protein becomes more rigid and less dynamic upon the cAMP binding as reflected in a 4 ± 0.5% decrease in its intrinsic coefficient of adiabatic compressibility. Finally, we estimate the hydration, ΔShyd, and configurational, ΔSconf, contributions to the binding entropy, ΔSb. We find that the binding entropy is determined by the fine balance between the ΔShyd and ΔSconf terms. In general, we discuss insights that are derived from a combination of volumetric and structural properties, in particular, emphasizing how measured changes in volume and compressibility can be interpreted in terms of hydration and dynamic properties of EPAC1 in its apo- and holo-forms.

Solvent effects on the molecular structures of crude gliadins as revealed by density and ultrasound velocity measurements

Gliadins were extracted from hard red spring wheat flour with 70% (v/v) aqueous ethanol and lyophilized. These crude gliadins were dissolved in 70% (v/v) aqueous ethanol or 4 mM acetic acid with or without ultrasonication. Precise measurements of the density and ultrasound velocity of the solutions were made at 20 °C. For non-sonicated solutions, crude gliadins solubilized in ethanol had a slightly larger partial specific volume (0.76 cm 3 g −1), and a larger partial specific adiabatic compressibility coefficient (15 × 10 −11 Pa −1) compared to those solubilized in acid (0.739 cm 3 g −1, 3.1 × 10 −11 Pa −1, respectively). Larger values are consistent with the existence of complexes formed by gliadins and lipids in aqueous ethanol solutions. Utrasonication had no effect on these protein–lipid complexes based on measurements of density, but it did alter the compressibility of gliadins in dilute acid (making them almost twice as compressible). Novel insights into gluten protein properties can be gained from compressibility measurements of solutions using ultrasonic resonators when coupled with measurements of protein specific volume.

Acoustic and Thermophysical Properties of Binary Liquid Mixtures of Primary Butanols with Hexane and Cyclohexane at 293.15 K

The experimental density and speed of ultrasound measurements, along with literature data, were used to calculate adiabatic and isothermal compressibility coefficients, the specific heat ratio, and isobaric thermal expansion coefficients for the binaries of 1-butanol with hexane and cyclohexane. They were also used to determine Beyer’s parameter of nonlinearity, B/A, and free intermolecular lengths, L. The free intermolecular lengths, L, calculated according to the Jacobson equation, were compared with values estimated from thermoacoustical parameters.

Adiabatic Compressibilities of Divalent Transition-Metal Perchlorates and Chlorides in N,N-Dimethylacetamide and Dimethylsulfoxide

Sound velocities of solutions of manganese(II), cobalt(II), nickel(II), copper(II), and zinc(II) perchlorates and chlorides in N,N-dimethylacetamide (DMA) and dimethylsulfoxide (DMSO) were measured at 298.15 K. Adiabatic compressibility coefficients of the solutions were determined, and apparent adiabatic molar compressibilities of the salts at infinite dilution were evaluated and discussed.