Experimental Density Data Research Articles

Acoustic and spectroscopic characterization of glycol ethers in vitamin B7 over the range of temperatures (288.15, 293.15, 298.15, 303.15) K

Density (ρ) and ultrasonic speed (u) of butoxyethanol and phenoxyethanol in aqueous solution of biotin concentrations (0.0012, 0.0017, 0.0022) mol·kg−1 at varying temperature range (288.15, 293.15, 298.15 and 303.15) K at 0.1 MPa were measured using Anton Paar DSA 5000 M. The volumetric and acoustical properties such as apparent molar properties (V∅), partial molar volume (V∅0),partial molar volume of transfer (ΔV∅0),apparent molar isentropic compression (K∅),partial molar isentropic compression (K∅0),partial molar isentropic compression of transfer are computed using the experimental data of density (ρ) and ultrasonic speed (u). This investigation is useful to understand the solvation behavior of biotin. Additionally, partial molar expansibilities (E∅0) along with their first order derivatives (∂E∅0/∂T)pare determined using the obtained experimental data. These results are effective in understanding the nature of interaction occurring inside the solution. Further, pair and triplet coefficients are evaluated which determines the structure making and breaking ability of glycol ethers in aqueous solution of biotin. Also, spectroscopic study of solutions is mentioned in current research which reveals the nature and strength of bond formation and various interactions in the mixture. The present study suggests the molecular interaction between the solute and solvent present in aqueous solution of Biotin (Vitamin B7) as solvent, butoxyethanol (BE) and phenoxyethanol (PE) as solute.

Thermophysical properties: Viscosity, density, and excess properties of 2-propanol and n-Decane mixtures from 283.15 K to 343.15 K under atmospheric conditions

To study the effects of temperature as well as molecular interaction of a fluid system on the thermophysical properties of 2-propanol and n-Decane binary mixture, the density (ρ), dynamic viscosity (η), speed of sound (u), and refractive index (nD) of pure 2-propanol and n-Decane, along with their binary mixtures, were experimentally measured across the entire compositional range at temperatures from 283.15 to 343.15 K and atmospheric pressure. These experimental measurements helped in the evaluation of various thermophysical properties, such as excess molar volume (vE), coefficient of thermal expansion (αE), and isentropic compressibility (κsE). The experimental dynamic viscosity (η) and density (ρ) data were used to evaluate kinematic viscosity (v) and Gibbs free energy (ΔG) of flow with an equation based on Eyring's absolute state theory, and their corresponding excess properties. The excess properties of the binary mixtures were correlated using a Redlich-Kister type polynomial equation via the least-squares regression method, with fitting parameters determined for the binary system. Moreover, the Prigogine–Flory–Patterson theory (PFP) was utilized to identify the primary molecular interactions contributing to the excess molar volume at 293.15, 308.15, and 323.15 K for the binary mixtures. Additionally, the capability of the Eyring-NRTL model was tested to predict the viscosity as well as vapor-liquid equilibrium (VLE) of the binary system, and the correlated model results agreed with literature data.

Molecular modeling and simulation of organic electrolyte solutions for lithium ion batteries.

Multi-criteria optimization is used for developing molecular models for ethylene carbonate (EC) and propylene carbonate (PC), organic solvents commonly used in Li-ion batteries. The molecular geometry and partial charges of the solvents are obtained from quantum mechanical calculations. Using a novel optimization strategy that combines systematic variations of the Lennard-Jones parameters with a reduced units approach, the models are fitted to experimental data on the liquid density, vapor pressure, relative permittivity, and self-diffusion coefficient. Since no experimental data for the self-diffusion coefficient of pure EC were available in the literature, they are measured in this work using a gradient-based nuclear magnetic resonance technique. For all pure component properties, excellent agreement between experiment and simulation is obtained. Moreover, the predictive capabilities of the new solvent models are assessed by comparison to experimental data for the liquid density and relative permittivity of mixtures of EC and PC. In addition, molecular models for the anions PF6-, BF4-, and ClO4- in solutions of their lithium electrolytes in PC are developed using experimental data on the solution densities. Finally, the self-diffusion coefficients of LiPF6 in PC and in aqueous solution are predicted and compared, showing that diffusion is much slower in the organic solution due to the formation of larger solvent shells around the ions. Furthermore, an analysis of the radial distribution functions in these solutions suggests that the ions have much less impact on the structure of the solvent PC than on water.

TAMie Force Field for Alkanethiols: Multifidelity Gaussian Processes for Dealing with Scarce Experimental Data.

This study extends the transferable anisotropic Mie potential (TAMie) to alkanethiols. The force field parameters are optimized by using an analytic equation of state as a surrogate model. Given the lack of experimental density data at elevated temperatures where Monte Carlo simulations have high statistical precision, the equation of state is supplemented by a linear multifidelity Gaussian process approach to bridge the temperature gap. Force field parameters are adjusted by minimizing squared deviations of calculated vapor pressures and liquid densities from experimental data of 1-propanethiol, 1-butanethiol and 1-pentanethiol leading to small mean absolute relative deviations in liquid densities and vapor pressures. The force field is transferable to higher 1-thiols, as shown for 1-hexanethiol and 1-octanethiol. Individual parameter sets are provided for methanethiol and ethanethiol. The shear viscosity of pure substances is predicted in fair agreement with experimental data, considering that it is not included in the parametrization. Further, the phase behavior of binary mixtures of alkanethiols with alkanes is studied, and predictions of the TAMie model are found in excellent agreement with experimental data.

An experimental-computational study on thermodynamic properties and intermolecular interactions of binary mixtures composed of quaternary ammonium salts-based deep eutectic solvents and [ETN] or [ACN]

To deep understand the thermodynamic properties and intermolecular interactions of quaternary ammonium salts-based deep eutectic solvents (DESs), two novel DESs systems ([TPAB]:[MA] and [TBAB]:[MA]) were synthesized using tetrapropylammonium bromide ([TPAB]) or tetrabutylammonium bromide ([TBAB]) as hydrogen bond acceptor (HBA) and malonic acid ([MA]) as hydrogen bond donor (HBD). Then, the ethanol (ETN) and acetonitrile (ACN) were used to prepare four DESs + solvent mixtures. Based on experimental data of density and surface tension of these four binary mixtures, the thermodynamic parameters such as apparent molar volume (Vϕ), excess molar volume (VE), limiting apparent molar expansibility (E0ϕ), molar surface entropy (s), molar surface Gibbs energy (gs), and molar surface enthalpy (h) were calculated. At the same temperature, the calculated VE values of binary mixtures were arranged in the following sequence: [TBAB]:[MA] + [ETN] > [TPAB]:[MA] + [ETN] > [TPAB]:[MA] + [ACN] > [TBAB]:[MA] + [ACN]. Based on the radial distribution functions (RDFs) theory, this observed phenomenon was attributed to the enhanced interaction between HBA and [ETN] in the DESs + [ETN] as compared to the interaction between HBA and [ACN] in the DESs + [ACN]. The predicted surface tension values (γ(pre)) of the four binary mixtures were calculated and highly correlated with the experimental surface tension values (γ(exp)). Moreover, the Br1 atom in [TPAB], the Br2 atom in [TBAB], and the H9 atom in [MA] were selected as reference sites. The interaction strength sequence between HBD and HBA was investigated using RDFs as follows: [TBAB]:[MA] + [ACN] > [TPAB]:[MA] + [ACN] > [TBAB]:[MA] + [ETN] > [TPAB]:[MA] + [ETN]. This study can provide an important theoretical support for further utilization of quaternary ammonium salts-based DESs.

Configuration rearrangement of squalane induced by carbon dioxide dissolution: A molecular simulation study

Squalane has emerged as a desirable absorbent material for carbon capture, utilization, and storage solutions due to its tunable sorption properties, microscopic structures, and cost-effectiveness in response to the increasing demand. Moreover, a thorough understanding of the fundamental characteristics of hydrocarbons and dissolved gases involved in the Fischer–Tropsch industrial synthesis processes is also essential for researching industrial purification and separation. However, these macromolecules may experience varying degrees of induced alterations in their structural rearrangement when absorbing absorbates, which impacts the performance indicators of squalane. This study examined the solubility characteristics of absorbents made from squalane and their interaction with gaseous CO2 molecules. The perturbed chain statistical associated fluid theory (PC–SAFT) was employed to comprehensively evaluate the macroscopic thermodynamic experimental density and solubility data. Simultaneously, the Monte Carlo (MC) simulation approach was utilized to investigate the rearrangement and swelling features of the squalane chain induced by the presence of CO2 gas in a broad spectrum of temperature and pressure conditions. This work indicated that elevated temperatures increased flexibility in the molecular structure of squalane, leading to a more pronounced spatial dispersion, while higher pressures may lead to spatial homogeneity and enhanced capacity for carrying additional CO2 molecules. The examples and methodologies presented demonstrate the effectiveness of molecular simulations in comprehending absorption–based phenomena at an atomistic and molecular level and offer essential guidance in forecasting the potential for separation, storage, or catalytic.

Development of Generalized Correlations for Predicting Density and Specific Heat of Nanofluids for Enhanced Heat Transfer

Objective: Energy-generating devices such as automotive vehicles, power reactors, computing machines etc. require effective cooling for safe and efficient operation. Additionally, at the same time, heat losses must be minimized. In industry, pure fluids such as water, air etc. are usually used for these purposes. Nanofluids have recently been explored as an alternative to traditional coolants. Nanofluids have attracted attention due to their superior thermophysical properties as compared to conventional fluids. Nanofluids are nanosized particles of metallic, non-metallic, or organic origin suspended in base fluids. Some examples of these nanoparticles include silver, copper, metal oxides, metal nitrides, carbon materials (such as carbon nanotubes, metal carbides) etc. Several options for base fluids exist, such as ethylene glycol, water, transformer oil, etc. Methods: The thermophysical properties of nanofluids of interest include thermal conductivity, viscosity, density, and specific heat. Predicting these physical properties, which depend upon particle concentration, temperatures, particle sizes, etc., is a significant challenge. Researchers have developed correlations for predicting these properties based on available experimental data. However, a thorough literature review suggests that generalized correlations do not exist, especially for the density and specific heat. Most researchers have done work on thermal conductivity and viscosity. The present work has developed generalized correlations to predict nanofluids' thermophysical properties density, and specific heat. Experimental data was collected for the various operating and geometric parameters affecting nanofluids' density and specific heat. Results: By performing regression analysis, four dimensionless correlations are proposed for each of predicting two important thermophysical properties, i.e., heat capacity and density of nanofluids. The developed correlations were compared with available experimental data. Conclusion: It was found that the correlations generated were fitted the experimental data for density and specific heat with an accuracy of ±10% band of actual value.

PρT measurements of 3-aminopropan-1-ol and N-(2-hydroxyethyl)morpholine from (293.15 to 473.15) K and up to 40 MPa and modeling with modified Tait and PC-SAFT equations

New density data has been reported for 3-aminopropan-1-ol (AP) and N-(2-hydroxyethyl)morpholine (NHEM) at temperatures ranging from (293.15–473.15) K at 19 pressures ranging from (0.1–40) MPa. The experimental measurements were carried out using an Anton Paar high-pressure vibrating tube densimeter with a combined expanded uncertainty of 1 kg m−3 at a 95 % confidence level. Contributions considered in the uncertainty analysis included the impurities in the materials used and apparatus specification. In addition, the density and speed of sound at ambient pressure (81.5 kPa) and temperatures (293.15–343.15) K were measured. The experimental density data were correlated with the modified Tait equation. Values of thermal expansion coefficient (αP ) and isothermal compressibility (κT) were calculated. The work is completed with the modeling of the experimental data using the perturbed-chain statistical associating fluid theory equation of state (PC-SAFT EOS). The parameters of the PC-SAFT equation of state, for the pure compounds, were determined by fitting the equation to the liquid PρT experimental data. Thermodynamic properties such as thermal expansion coefficient (αP), isothermal compressibility (κT), isobaric heat capacity (CP), and speed of sound (u) were calculated with the obtain parameters. Good agreement between experimental data and derived properties represented the modeling accuracy with the obtained parameters.

A Theoretical and Experimental Approach to Ultrasonic Velocities, Densities, and Refractive Indices in Benzene and Aniline Mixture

The study investigates the theoretical velocities of binary liquid mixtures comprising Aniline and Benzene under 2MHz ultrasonic waves at temperatures of 303.15K, 308.15K, and 313.15K, examined in relation to mole fraction. Experimental data is compared with various theoretical models, including Nomoto theory (NOM), Ideal mixing relation (IMR), Impedance Relation (IR), Rao’s Specific Velocity Method (R), and Junjie’s relations (JR). The work reflects the changes in refractive index with varying liquid density across different mole fractions, explaining observed impacts on ultrasonic velocities. To assess the goodness of fit, Chi-square tests and average percentage errors are employed, allowing for an evaluation of the relative applicability of these theories within the studied systems. The study also explores how the thermos-acoustical characteristics of the systems evolve concerning the mole fraction of a common molecule, shedding light on molecular interactions. Furthermore, various parameters for the binary mixture, such as discrepancies in ultrasonic velocity, excess isentropic compressibility, surplus acoustic impedance, excess intermolecular free length, and molar refraction deviation, are computed using experimental data of density, refractive index, and ultrasonic velocities at different mole fractions of benzene in the aniline-benzene mixture. These calculations serve to reflect the intermolecular interactions present in the binary liquid mixture.

Systematic investigation on semi-empirical thermodynamic quantities of excited nuclei using canonical ensemble

Semi-empirical thermodynamic quantities (TQs) of 78 nuclei ranging from 43Sc to 243Pu have been systematically investigated in the temperature region below 1 MeV using the thermodynamic canonical ensemble. The latter is carried out by taking into account the experimental nuclear level density (NLD) data measured using the Oslo method for the low-excitation region below the neutron binding energy B n combining with the back-shifted Fermi gas NLD model for the excitation energy from B n to about 250 MeV. In particular, the uncertainty of the TQs propagating from the fluctuation of the experimental NLD data has been, for the first time, calculated. The results obtained indicate that the uncertainty of TQs due to the experimental NLD is incomparable with the changes caused by the nuclear structure effects. The free energy of even–even nuclei behaves differently from that of odd-A ones. The total energy in the low-temperature region below T E ≃ 0.4 − 0.6 MeV for medium-mass nuclei and T E ≃ 0.2 − 0.4 MeV for heavy-mass ones slowly varies. When temperature is from T E to 1 MeV, the total energy increases extremely faster than the increase of temperature, exhibiting the constant-temperature behavior. The entropy exhibits an abrupt change in their slope at T S ≃ 0.2 − 0.4 MeV in medium-mass nuclei and T S ≃ 0.5 − 0.6 MeV in heavy-mass ones. The existence of T E and T S has been interpreted due to the breaking of the first Cooper pair. Finally, the heat capacity shows a strongly pronounced S-shape in nuclei belonging to the rare-earth region. The temperatures defined at the center of the S − shaped heat capacities, which are known to closely relate to the critical temperature of the pairing phase transition T C, are quite close to those theoretically predicted, namely T C ≈ 0.5Δ − 0.6Δ with Δ = 12A −1/2 being the empirical pairing gap at zero temperature. The semi-empirical TQs obtained in the present work can be, therefore, a reliable data source to test and/or validate many nuclear thermodynamical models and to examine some nuclear structure properties such as pairing and deformation.

The water bimodal inherent structure and the liquid-liquid transition as proposed by the experimental density data.

The bulk water density data are studied in a very large temperature-pressure range, from stable liquid to glass in the frame of water polymorphism. Because this thermodynamic variable evidences a crossover T*, above which the hydrogen bond (HB) is unable to arrange tetrahedral networks, the T-dependence of their isobars was considered. Such an analysis also shows pressure, P*, around which their thermal behaviors are completely different: concave below P* (with maxima and minima) and convex above (without extremes). Having ρ's measured values of the bimodal structures of the liquid phase, HDL (ρHDL), made of not-bonded monomers (ρNHB) and partially bonded dimers plus trimers (ρNHB), and LDL tetramers (ρLDL) the isobars of the relative distributions [W(P, T)] of the three species (WLDL, WPHB, and WNHB) have been evaluated. The results were studied by means of a logistic function (LF) that details the evolutions of the relative polpulations of the water LDL and HDL phases by decreasing T (for the isobars, in the range of 0.1-400 MPa). The LFs analysis obtained by proposing a full connection between liquid water from its supercooled metastable phase to the stable up to the boiling temperature identifies the Widom line quite satisfactorily and fully supports the presence of the liquid-liquid critical point in the deep supercooled region, located at about 190K and in the range 200 > P > 180 MPa.

Densities and isobaric heat capacities at high pressures of aqueous solutions of 2-diethylaminoethanol (DEAE) or 2-ethylaminoethanol (EAE) for CO2 capture

Densities and isobaric heat capacities of DEAE + H2O and EAE + H2O systems are presented in this paper. Density measurements were carried out at high pressure (up to 100 MPa) and temperatures from (293.15 to 393.15) K, with amine mass fractions of 0.1; 0.2; 0.3 and 0.4. These data were gathered using a vibrating tube densimeter (Anton Paar DMA HPM) with a relative expanded uncertainty of ±0.1 % (k = 2). A non-adiabatic quasi-isothermal flow calorimeter was used for isobaric heat capacity measurements with a relative expanded uncertainty better than 1 % (k = 2). Measurements reached pressures up to 25 MPa, and temperatures from (293.15 to 353.15) K, with amine mass fractions of 0.1; 0.2; 0.3 and 0.4. Both amine DEAE + H2O and EAE + H2O systems show a density and isobaric heat capacity decrease with amine mass fraction increase. Density data as a function of temperature, pressure and molality were fitted using a modified Tammann-Tait empirical equation of state. Furthermore, isobaric heat capacity data were correlated using an empirical function of temperature and amine mass fraction, but not pressure due to its lack of sensitivity in the measured data. Both correlations are in good agreement with the uncertainties. Comparison with experimental density data available in literature showed lower deviations than the associated uncertainties. Our isobaric heat capacity experimental data agree well with the scarce literature.

Density, Speed of Sound and Derived Properties of Binary Mixtures Propiophenone + Butoxyethanol at T = (303.15, 308.15, 313.15 and 318.15) K

The current study reports the experimental density (ρ) and sound speed (u) values for binary mixes of liquids propiophenone + 2-butoxyethanol at atmospheric pressure (0.1 MPa) and T = (303.15, 308.15, 313.15 and 318.15) K for the full spectrum of composition. densities and sound speed measurements from experiments have been used to estimate excess isentropic compressibility (κsE), excess molar volume (VEm), excess molar isentropic compressibility (KEs,m), excess isobaric thermal expansivity (αEp) and excess sound speed (uE). The Redlich-Kister polynomials were used to correlate excess parameters. Excess partial molar volume quantities (VEm,1 and VEm,2) at infinite dilution and their limiting values (V0Em,1 and V0Em,2) have been analytically determined using Redlich-Kister polynomials from the experimental density data. The results have been analyzed in light of strength and interactions among molecular entities scope and extent prevalent in these mixtures.

Thermo-acoustic properties of monosaccharides D(−)-ribose and D(+)-xylose in aqueous diammonium hydrogen phosphate solutions at different temperatures

The volumetric and acoustic properties are used for investigating the interactions of polyhydroxy solutes D(−)-ribose and D(+)-xylose in different concentrations of diammonium hydrogen phosphate (DAP) solutions. Densities and speeds of sound of D(−)-ribose and D(+)-xylose in aqueous diammonium hydrogen phosphate (DAP) solutions have been measured over a temperature range of (298.15–318.15) K and at experimental pressure p = 0.1 MPa. Different parameters viz apparent molar volumes, Vϕ, partial molar volumes, apparent molar isentropic compression, partial molar isentropic compression, partial molar volume of transfer and molar isentropic compression of transfer are obtained using experimental density and ultrasonic speed data. The calculated parameters are discussed in rapports of solute–solvent interactions in solutions indicated the presence of ion-ion, ion-polar, hydrophilic-hydrophilic and hydrophobic–hydrophobic interactions in these ternary solutions, which was also confirmed from obtained positive values of apparent molar volume and negative values of apparent molar isentropic compressibility. Pair (VAB, KAB) and triplet (VABB, KABB) interaction coefficients determined by means of McMillan-Mayer theory are used to acquire valuable information about the dominance of pairwise interactions in the studied mixtures.

Viscosities and Densities of Binary and Ternary Mixtures of Aliphatic and Polyaromatic Hydrocarbons: Pyrene +1-Methylnaphthalene + Dodecane at T = (293.15 to 343.15) K. Experiment and Modeling.

This work presents new experimental viscosity and density data for aromatic and polyaromatic compounds in binary and ternary pyrene, 1-methylnaphthalene, and dodecane mixtures. The lack of experimental viscosity data for these mixtures requires the development of a new database, which is vital for understanding the behavior of mixtures in more complex systems, such as asphaltenes and fuels. The mixtures proposed in this work have been measured over a temperature range of (293.15 to 343.15) K at atmospheric pressure. Several mixture compositions have been studied at these conditions: 1.0, 2.5, 5.0, 7.5, 10.0, 12.5, and 15.0% pyrene mass fraction. The concentration of pyrene correlates with an increase in the viscosity and density values. At the lowest temperature in binary mixtures, the corresponding values reach 4.4217 mPa·s for viscosity and 1.0447 × 103 kg·m-3 for density, respectively. In ternary mixtures, the introduction of dodecane leads to the lowest maximum values of 3.5555 mPa·s for viscosity and 1.0112 × 103 kg·m-3 for density at the same temperature. The experimental data have been employed for the specific modification of viscosity models. These modifications could facilitate the prediction of the viscosity of mixtures that are more complex than those presented in this work. Various viscosity models have been employed, such as Linear, Ratcliff and Khan, modified UNIFAC-Visco, and Krieger-Dougherty. The settings in the models used reliably reproduce the experiment reliably. However, the Ratcliff model agrees excellently with the experiment, having a low standard deviation (2.0%) compared to other models. Furthermore, a model based on the equation of state of Guo is proposed to predict the viscosity values by modifying the specific parameters and adjusting them to the mixtures proposed in this work. The results from this study are compared to previous work, where pyrene, toluene, and heptane mixtures were analyzed. In this case, we find that the decrease of aggregation grade in the present systems is predicted by the model fixed in this work.

Combined thermodynamic and theoretical study on ether-functionalized ionic liquid mixture systems of [MOEmim][TFSI] with ACN/GBL

Ether-functionalized ionic liquids (ILs) have a higher fluidity and are widely used in a variety of applications due to the introduction of the ether group. In order to better understand the relationship between properties and internal interactions of ether-based ILs, we prepared two ether-functionalized ILs 1–2-methoxyethyl-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide ([MOEmim][TFSI]) with acetonitrile (ACN) or γ-butyrolactone (GBL) mixture systems, and investigated the changes of their thermodynamic properties and internal interaction behaviors over the entire concentration range. First, the thermodynamic properties such as dynamic viscosity, density and electrical conductivity of the two mixture systems were measured from 288.15 K to 343.15 K. The excess molar volume (VE), and viscosity deviation (Δη) were calculated by using the measured experimental density and dynamic viscosity data, which can provide microscopic information on the interactions. Further, the intermolecular interactions of the mixture systems were evaluated by density functional theory (DFT) calculations. The sigma–profile (σ–profile) provided insight into the hydrogen bonds (H-bonds) and molecular surfaces interactions. We also used molecular dynamics simulations (MD) to study ILs mixtures in many different solvent concentrations, thereby providing a microscopic and macroscopic characterization of fluid structure, molecular aggregation, and intermolecular forces.

The use of simple structural parameters of energetic metal-organic frameworks to assess their density

A new method is presented for accurately estimating the density (D) of energetic material-organic frameworks (EMOFs), which has vital role in determining their performance. The experimental density data for 124 EMOFs, which are composed of five or six-membered heterocyclic rings, has been used to develop and analyze the model. The model is constructed based on simple structural parameters and can be easily applied to EMOFs with complex compositions and structures. The performance of the new model in estimating density has been compared to the Dalirandeh et al. model. The values of statistical factors comprising mean absolute error (MAE), maximum absolute error (AEmax), root mean square error (RMSE), mean absolute percent error (MAPE), and coefficient of determination (R2) for Dalirandeh et al./new model are 0.09/0.07, 0.33/0.23, 0.12/0.10, 4.21/3.50, and 0.94/0.96, respectively. Statistical validations and applicability domain (AD) assessments have confirmed that the new model provides high accuracy, precision, reliability, and goodness-of-fit.

Thymoquinone-Micellar Interactions: A physico-chemical investigation at molecular level

Thymoquinone (TQ) is considered the most-active component of the well-known essential oil of the black cumin/seeds (Nigella sativa L.), also known for its wide-spectrum anticancer and other pharmacological potentials since ancient times. Apart from its thermo- and photo-sensitive nature, TQ has also been reported to demonstrate strong hydrophobicity and low bioavailability. These physico-chemicals, properties hinder the development of a successful oral dosage formulation. Interaction of the pharmacologically active molecule with biological membranes is crucial step to manifest health-related effects. However, further insight into the biophysical interactions of “active” natural chemotherapeutics with cellular membranes can play a vital role in designing and developing new anti-cancer regimens. In this context pseudo-membrane models comprising ionic and non-ionic micelles offer a useful way to explore in vitro drug-membrane interactions at the molecular level. The present study focuses on the physicochemical interactions of a thymoquinone (TQ) with micelles of ionic (dodecyl trimethylammonium bromide, DTAB; and sodium dodecyl sulfate, SDS) and non-ionic (tween-80 and TX-100) surfactants at the molecular level in aqueous medium. Volumetric and acoustic parameters (apparent molar volume (ɸV), isentropic compressibility (Ks), apparent molar isentropic compressibility (ɸk), specific acoustic impedance (Z), relative association (RA), intermolecular free length (Lf)) are calculated from experimental data of density and sound velocity and interpreted in terms of solute/solvent–solute/solvent interactions using the co-sphere overlap model and the electrostriction effect. Further, UV spectroscopy and conductivity studies are used to predict the locus of TQ in the micelles, binding constant (Kb), partition coefficient (Kc), and free energy changes of TQ-micelle systems in the presence of surfactants. The results show that the binding and partitioning of TQ is more significant with TX-100 as compared with other ionic and non-ionic surfactants used.

Dislocation phenomena described with free volume concept and Eyring's rate process theory.

Dislocation phenomena in solids under simple shear stress are theoretically addressed with the free volume concept and Eyring's rate process theory for obtaining a generic and unified description. The obtained equations do not have any restrictions to specific materials and are compared with various theories and empirical equations like the Hall-Petch and its inverse forms. Moreover, our equations are used to fit experimental data of mechanical properties and dislocation density against grain sizes available in the literature. A good agreement with observations is achieved, indicating that our theoretical framework is sound. Our findings provide a theoretical foundation for the very common dislocation phenomena observed among many solid materials including pure metals, metallic alloys, ceramics, and even geological scale entities, potentially clearing out many inconsistencies and puzzles in the literature.

Investigation of plasma parameters, distributions, and optical emission for the anti-microbial performance of non-woven fabric under direct current glow discharge

The distribution of electron temperature Te and density Ne for direct current glow plasma discharge was investigated, using a single Langmuir probe, inserted inside the plasma cell. The radial temperature distribution has the same values, except with a small increment variation at the cathode edge, and an axial decrement for the temperature Te distribution profiles from the cathode fall region, passing the abnormal glow region, up to the faraway axial region.The radial distribution of the electron density Ne has its highest value at the cathode, with very intense plasma at the cathode fall region, and more Ne decrement in the abnormal glow region, passing the abnormal glow region up to the faraway axial region. In the axial Ne distribution, an increase in Ne from the cathode fall region reaches maximum values in the abnormal glow region and decreases in the faraway axial region.The optimal plasma surface treatment of non-woven silk fabric (n-WSF) can be achieved by utilizing a high plasma density and low energy of electrons to inactivate viable cells attached to (n-WSF) at very short application times, leading to complete inactivation, where the bacterial inactivation rate increases in the abnormal glow region. Based on analyses of the experimental data of initial and final densities of viable cells using survival curves in the abnormal glow discharge region, a dramatic inhibitory effect of plasma discharge on the residual survival microbe ratio was observed.