Liquid densities of the hydrocarbons 1-hexene, 2,4-dimethylhexane, 2,2,4-trimethylpentane, and n-heptane were measured over a wide range of temperatures (293.15 K to 393.15 K) and pressures (up to 120 MPa), substantially extending the state range covered by previously available literature data. The density data were modeled using both an empirical correlation as well as a molecular-based equation of state (EOS). For each substance, an empirical Tammann–Tait correlation was developed that reproduces the new measurements with an average absolute deviation (AAD) of about 0.01
Densities, dynamic viscosities, and refractive indices were experimentally determined for the binary systems (2-chloropropane + diethyl ether, 2-chloropropane + diisopropyl ether, and 2-chloropropane + methyl tert-butyl ether) over the entire composition range, at five temperatures from 283.15 K to 303.15 K and atmospheric pressure. To the best of our knowledge, no thermophysical data have been previously reported for these three binary systems. From the experimental measurements, the excess molar volume ( V^E ), excess refractive index ( n_D^E ), and viscosity deviation ( Δη ) were derived and correlated as a function of composition using the Redlich–Kister equation, with the number of adjustable parameters selected according to Fisher’s test. For the three systems, V^E , n_D^E , and Δη were found to be negative over the whole composition and temperature range, indicating the existence of specific dipole–dipole and weak Cl ⋯ O halogen-bond-type interactions between 2-chloropropane and the ether molecules, together with an efficient molecular packing effect. In addition, the PC-SAFT equation of state was applied to model the density and excess molar volume of the three mixtures, using a predictive approach ( k_ij=0 ) and a fitted approach in which the binary interaction parameter was regressed against the experimental V^E data. The new experimental data and modeling results reported in this work provide a valuable contribution toward the thermophysical characterization of chloroalkane + ether systems, relevant for process design and simulation in the chemical and petrochemical industries
A Monte Carlo Ray Tracing (MCRT) homogenization is proposed to compute the spectral effective radiative and optical characteristics ( α _eff , σ _eff , g_eff , n_eff , k_eff ) of real heterogeneous semi-transparent media. Performed on statistically representative numerical microstructures, with the knowledge of the intrinsic indices of the constituents identified from normal-hemispherical reflectance and transmittance measurements, the method delivers all five characteristics in a single forward pass, with no further inversion: in particular, the asymmetry factor is read directly from the ray statistics, and the effective refractive index is obtained by a numerical time-of-flight method free of any external assumption. Because it operates on the microstructure itself, the approach assumes no particular object shape. It is demonstrated on two real aluminosilicate fibrous insulators, MAFTEC 96 and FOX. The practical relevance of the identified characteristics is illustrated by coupled conductive–radiative simulations compared against transient temperature measurements for both materials. The comparison shows that the identified characteristics capture the radiative contribution to heat transfer, and that a gray diffusion (Rosseland) approximation remains insufficient even for thick semi-transparent media, so that full spectral coupling is needed to reproduce the experimental response.
The Boyle curve is shown to be nearly a parabola on the density–temperature plane. This similarity follows from the van der Waals equation, analogously to some other ideal or characteristic lines like the Zeno line. The accuracy of the found similarity was estimated on the basis of the analysis of numerical and experimental data for the model systems (Mie potentials in 3D and 2D spaces) and real substances. For the model systems, the maximal errors can reach ∼ 5 ∼ 10
The solubility of carbon dioxide (CO2) in binary and ternary solvent mixtures composed of polyethylene glycol 400 (PEG 400), ethylene glycol (EG), and a thymol–camphor-based hydrophobic deep eutectic solvent (TC-HDES) was experimentally investigated at temperatures of 298.15 and 308.15 K and pressures up to 0.5 MPa. In addition, selected thermophysical properties, including density, were measured to support the analysis of gas–liquid equilibrium behavior. All solvent compositions studied for CO2 absorption were confirmed to remain in the homogeneous liquid phase under the investigated conditions. Henry’s law constants indicate that PEG 400 exhibits the highest CO2 solubility (4.53 MPa), followed by the TC-HDES (10.3 MPa), while EG shows significantly lower solubility (43.8 MPa). To gain insight into solute–solvent interactions at the molecular level, the preferential solvation model was applied to the experimental data. The results suggest that PEG 400 preferentially occupies the solvation shell of CO2 in both binary and ternary mixtures, dominating over EG and TC-HDES. This behavior is attributed to the multi-oxyethylene structure of PEG 400, which promotes favorable interactions with CO2. The combined experimental and modeling results provide useful insight into the design of mixed-solvent systems for CO2 capture, enabling improved performance through appropriate selection of solvent composition, while considering practical constraints such as viscosity and cost.
To optimize the photoacoustic measurement of metal and semiconductor solid samples acting as surface absorbers, we shorten the data acquisition time by 90
Under highly focused photon irradiation, the energy cascade induces a marked thermal non-equilibrium between optical phonons (OPs) and acoustic phonons (APs) in 2D material, which is critical in optothermal Raman-based thermal transport characterization. Previous optothermal Raman techniques ignored the thermal non-equilibrium effect between OPs and APs, introducing serious errors into the measurement of interfacial thermal resistance. Here, we combine Raman-based experiments, three-dimensional finite element thermal simulation, and rigorous optical interference consideration to simultaneously determine interfacial thermal resistance and the lumped energy coupling factor between OPs and APs. When the OPs–APs thermal non-equilibrium is considered, the interfacial thermal resistance for the nm-thick MoS2 supported by SiO2 is determined to be 1.1 to 11.2 × 10–7 m2·K·W−1, respectively. In comparison, R_tc^^'' is found to be overestimated by 374
The growing demand for efficient heat transfer and energy conversion systems require advanced working fluids with superior thermal transport properties. In this work, MgO, and Fe3O4 nanoparticles were synthesized by using chemical coprecipitation method. Then, 40:60
Chemical absorption using aqueous alkanolamine solutions remains the benchmark technology for post-combustion CO_2 capture, and diglycolamine (DGA) has emerged as an attractive solvent due to its high CO_2 loading capacity and favorable absorption kinetics. Accurate knowledge of surface tension is essential for the design of absorber–stripper units, yet the surface tension of DGA + water mixtures has, until now, only been reported in the literature at a single temperature (303.15 K), limiting the ability to model this system under other industrially conditions. In this work, the surface tension of DGA + water mixtures was experimentally measured over the entire composition range at four temperatures, T = 293.15 K to 323.15 K, at atmospheric pressure. To the best of our knowledge, this constitutes the first systematic multi-temperature data set for this binary system. Surface tension decreases with increasing temperature and increases with DGA content; the surface tension deviation is negative across all compositions and temperatures, indicating preferential accumulation of DGA at the liquid surface. The experimental surface tension data were modeled with Density Gradient Theory (DGT) + Peng–Robinson equation of state (PR EoS) model, with the binary interaction parameter k_ij regressed at each temperature, achieving an overall deviation of 0.67 % . Furthermore, it was found that the binary mixture is not azeotropic and DGA accumulates at the interface in certain mixture compositions. This experimental and modeling study provides a more complete thermophysical characterization of DGA + water, relevant to the design of CO_2 capture processes.
2,4,6-Trinitro-3-bromoanisole (TNBA) is a low-sensitivity melt-cast explosive carrier with higher energetic performance than TNT and has potential use as an alternative melt-cast component. The solid–liquid equilibrium solubility of TNBA in nine ethyl acetate + cyclohexane binary mixtures was measured by a laser dynamic method at 278.15 to 318.15 K under atmospheric pressure. At a fixed solvent composition, the mole fraction solubility increased with temperature; at a fixed temperature, it increased with the mole fraction of ethyl acetate. TNBA was only sparingly soluble in cyclohexane, suggesting that cyclohexane may be used as an antisolvent for TNBA crystallization. The experimental data were correlated with the modified Apelblat, Yaws, Buchowski–Książczak λh, and Jouyban–Acree models. The modified Apelblat and Yaws equations gave the most accurate correlations, with overall ARD values below 0.006 and RMSD values below 1.0 × 10–3. The Jouyban–Acree model also described the temperature–composition dependence well, with R2 = 0.9998 and RMSD = 0.4050 × 10–3. Thermodynamic analysis showed that TNBA dissolution is endothermic, with a favorable entropy contribution, while the enthalpic contribution is dominant (
2-Methylpyridine and 2-methylpyrazine form azeotropes with water, limiting the applicability of conventional distillation for their separation from aqueous mixtures. In addition, LLE data for acetophenone-containing systems remain scarce despite the broad industrial relevance of acetophenone. In this study, the LLE data were acquired for ternary systems of water + toluene + 2-methylpyridine, water + toluene + 2-methylpyrazine, and water + toluene + acetophenone at 298.15 and 313.15 K. Measured LLE data were successfully correlated by the NRTL model, and regressed binary interaction parameters were validated by topological analysis of the dimensionless molar Gibbs energy of mixing. The obtained LLE data were also utilized to evaluate the predictive capability of two classes of models: group-contribution methods (GCMs) and quantum-chemistry-based models. The studied GCMs included original UNIFAC, UNIFAC-LL, and modified UNIFAC (Dortmund), whereas the COSMO-based models comprised COSMO-SAC and COSMO-RS at the TZVP and TZVPD-FINE theory levels. Overall, all studied predictive models provided qualitatively acceptable predictions of the LLE behaviour. Among them, UNIFAC-LL showed the best overall predictive capability, whereas COSMO-SAC displayed the weakest performance. For COSMO-RS, the TZVPD-FINE level provided more accurate predictions of the experimental data than the TZVP level. UNIFAC performed better than modified UNIFAC (Dortmund) for the water + toluene + 2-methylpyridine system. In contrast, modified UNIFAC (Dortmund) yielded more accurate predictions than UNIFAC in the other two studied ternary systems.
Solar dryers are challenged to maintain a homogeneous drying air temperature because cloud cover and rapid fluctuations in solar radiation disrupt heat supply, reducing efficiency and process reliability. Integrating phase change materials (PCMs) provides thermal energy storage that reduces these variations and limits temperature drops during low solar radiation periods. In this work, a double pass solar air heater (DPSAH) drying system was developed and tested under real outdoor conditions to achieve more stable and effective drying of agricultural products. An eco-friendly eutectic PCM doped with hexagonal boron nitride (hBN) and graphene (GN) nanoparticles was incorporated into the DPSAH and connected to a drying cabinet to promote uniform drying. Field experiments were performed on Urfa pepper in Şanlıurfa, Türkiye, a hot climate region locally. Experiments were performed at inlet air velocities of 3 m·s−1, 6 m·s−1, and 9 m·s−1 using a two-step charging-discharging process. At each air velocity, four DPSAH dryers were compared against open sun drying. The results showed that GN-doped PCM significantly improved the drying performance. At an inlet air velocity of 6 m·s−1, the PCM-GN integrated DPSAH (DG) configuration delivered the highest performance, achieving a useful heat gain of 462.6 W and an average thermal efficiency of 83.4
Densities and viscosities of binary mixtures comprising 2-(dimethylamino)ethanol (DMAE) and a homologous series of 1-alkanols (1-pentanol to 1-decanol) were investigated to elucidate their molecular interactions and non-ideal thermophysical behavior. The derived properties, including excess molar volumes (VE) and viscosity deviations (Δη), exhibit positive and negative deviations from ideality, respectively. The magnitudes of both VE and Δη increase systematically with the elongation of the alkyl chain, indicating that the disruption of the alcohol’s self-associated hydrogen-bonded networks and steric hindrance dominate over specific cross-interactions. Furthermore, the Barker–Henderson (BH) perturbation theory was successfully applied to model the volumetric behavior of these complex mixtures. The BH framework demonstrated reasonable accuracy in predicting mixture densities, yielding average absolute deviations (AAD) ranging from 0.033
As the key heat storage and transfer medium in concentrated solar power (CSP) systems, molten salts’ thermophysical properties, such as thermal conductivity, specific heat capacity, and thermal stability, critically determine the systems energy conversion efficiency and economic viability. However, conventional molten salts suffer from low thermal conductivity and limited energy storage density, restricting their application in high-temperature thermal energy storage. Recent advances show that doping with nanoparticles, such as Al2O3, CuO, and SiO2, can significantly improve these properties. Nevertheless, systematic studies on quaternary molten salt systems remain scarce. In this work, we focus on the quaternary eutectic salt H15 (15 wt
There is robust industrial demand for thermodynamic and thermophysical property data for chemical substances and materials. Unresolved inconsistencies and unexplained anomalies in the data are frequently revealed by data users. Inconsistency appears when either multiple measurements significantly deviate from each other beyond reasonable uncertainties or different reported properties do not obey thermodynamic relations between them. Anomaly here means a reported value or behavior significantly deviating from expectation based on theory or correlation. To address such issues, we have launched the new Thermodynamics Research Center (TRC) Research Challenge Search website. The goals of this service are to encourage researchers to address these problems, identify the need for additional theoretical and experimental development, support the justification of related research proposals, and ultimately provide users with reliable data. This publication provides an overview of the service, presents the current collection of cases, and describes the procedures for user feedback and contribution.
The present research comprehensively explored the thermal performance of various roof retrofitting strategies, including insulation, solar reflectance, and their combination, to avoid high temperatures in the attic and thus improve indoor thermal conditions in the master bedroom in a typical terrace house in Malaysia’s hot and humid climate. In this study, 17 strategies were simulated in DesignBuilder to evaluate their effects on indoor temperature and heat flux in the master bedroom and the attic. The innovation lies in modeling a bio-based phase change material (Bio-PCM) panel as a roof component, both as a standalone strategy and in combination with other strategies. The heat-reflective paint strategy excelled at managing indoor temperatures by reflecting solar radiation, lowering temperatures by 1.3 °C and 2.0 °C in the master bedroom and the attic, respectively. However, the combined strategy of single-sided aluminum woven foil, heat-reflective paint, and Bio-PCM panel is the most effective in minimizing conductive and radiant heat transfer. The reduction in heat flux in the master bedroom by 67
Nanofluids with ultrasmall nanoparticles below 10 nm stabilized in organic liquids lack a deeper characterization with respect to the effective thermal conductivity λeff. This study investigates nanofluids consisting of cerium dioxide (CeO2) nanoparticles and cyclohexane. To elaborate the influence of particle size, surface modification, and particle volume fraction φp, nearly spherical nanoparticles with very small core sizes dcore from (3 to 6) nm covered by modifiers of varying chain length were examined at φp of up to 0.045. λeff was measured using a guarded parallel-plate instrument at temperatures from (283.15 to 313.15) K and at atmospheric pressure with an expanded uncertainty of 2.5
Deep eutectic solvents (DESs) are promising green CO2 absorbents due to their low vapor pressure, high designability, and environmental friendliness. In this work, diethylamine hydrochloride (DH) was used as the hydrogen bond acceptor (HBA), and ethylene glycol (EG) and diethylene glycol (DEG) as the hydrogen bond donors (HBDs). Six homogeneous, room-temperature-stable DESs were synthesized at HBA: HBD molar ratios from 1:4 to 1:6. Their densities and viscosities were measured at 303.15–333.15 K, and CO2 solubilities were determined at pressures of 0.206–2.310 MPa. A soft‑SAFT thermodynamic model was established to correlate the densities, and a temperature–dependent binary interaction parameter was introduced to correlate CO2 solubilities. The improved free volume theory (FVT) was coupled to achieve accurate viscosity calculation. The average absolute relative deviations for density, CO2 phase equilibrium, and viscosity were 0.028
Dilute-gas viscosity is a fundamental transport property governed by binary molecular collisions and is widely used as a reference term in dense-fluid viscosity models. In this work, a physics-constrained symbolic regression framework is developed for predicting dilute-gas viscosity through the conventional Chapman–Enskog framework and a new reduced Boyle-scaled collision integral. Instead of correlating viscosity directly, the viscosity data are transformed into a dimensionless collision integral using the Boyle temperature and Boyle length derived from the second virial coefficient. A comprehensive database containing 87 fluids and 11,263 dilute-gas viscosity data points was constructed by combining high-accuracy ab initio data with carefully screened and zero-density-extrapolated experimental data. The collision-integral model was formulated as a decomposed correlation consisting of a spherical reference term, a nonpolar correction term, and a polar correction term, with additional empirical extensions for quantum and associating fluids. Symbolic regression was used to identify the analytical expression of each term considering accuracy, numerical stability, and physical consistency. The resulting model gives an overall AARD of 2.00
Reliable thermal conductivity data for unconsolidated geological materials are essential for accurate geothermal resource assessment and subsurface thermal modeling, particularly when utilizing drilling cuttings for thermophysical characterization. However, conventional needle-probe methods are often impractical for high-throughput analysis due to lengthy measurement cycles and the uncertainty arising from random probe-sample contact variability. To address this limitation, we developed a novel quartz-cell-assisted protocol for the Thermal Conductivity Scanner (TCS), enabling rapid estimation of thermal conductivity in unconsolidated samples. Six calibration models were rigorously evaluated using paired measurements from 30 block reference materials; model selection was optimized via leave-one-out cross-validation (LOOCV) and subsequently validated using independent powder samples. The power-law function was identified as the most robust empirical conversion equation for this specific TCS configuration. Application of this function to 20 powder samples yielded calibrated values consistent with independent transient needle-probe measurements, demonstrating negligible bias (0.000569 W·m−1·K−1), low mean absolute error (MAE = 0.0326 W·m−1·K−1), and minimal root mean square error (RMSE = 0.0394 W·m−1·K−1), with a mean absolute percentage error (MAPE) of 8.74
