Explore the vast range of titles available.

The size of the drug particles is one of the essential factors for the proper absorption of the drug compared to the dose of the drug. When particle size is decreased, drug uptake into the body increases. Recent studies have revealed that the rapid expansion of supercritical solution with cosolvent plays a significant role in preparing micron and submicron particles. This paper examines the preparation of Erlotinib hydrochloride nanoparticles using a supercritical solution through the cosolvent method for the first time. An examination of the parameters of temperature (318–338 K), pressures (15–25 MPa) and nozzle diameter (300–700 μm) was investigated by Box-Behnken design, and their respective effects on particle size revealed that the nozzle diameter has a more significant impact on particle size than the other parameters. The smallest particles were produced at temperature 338 K, pressure 20 MPa, and nozzle diameter 700 μm. Besides, the ERL nanoparticles were characterized using SEM, DLS, XRD, FTIR, and DSC analyses. Finally, the results showed that the average size of the ERL particles decreased from 31.6 μm to 200–1100 nm.

Heat transfer rate and amount of pressure drop for highly stabled nanofluids loaded with polyvinyl alcohol-treated graphene oxide (PVA-GO) were experimentally investigated in a horizontal copper duct with the uniform heat flux on outer surface of test section. To meet those goals, we produced GO through a wet-based exfoliation method and followed by functionalization of GO with PVA. As a phase of study, some nanofluids including PVA-GO with different concentration were prepared and thermo-physical and rheological properties were experimentally obtained. The thermo-physical attributes such as thermal conductivity, viscosity and density of the synthesized samples with various PVA-GO concentrations (0.025, 0.05, and 0.1 mass%) were experimentally investigated at the first phase of this article. Possessing the thermo-physical properties open a precise gate to measure the heat transfer rate (h & Nu) and frication factor for water/PVA-GO nanofluids and finally compared with the working fluid (water). As the second phase of study, influence of parameters such as concentration of PVA-GO and the flow rate on heat transfer parameters such as Nu, friction factor, and performance index were investigated. Overall, processing heat transfer systems with highly conductive water/PVA-GO nanofluids even at low concentrations results in higher heat transfer rate and overall performance of system/cycles.

Activated carbons are used in industrial applications; their cost is a major barrier to their more widespread application. Regeneration of activated carbons is indispensable to minimize operational costs and product wastage. Supercritical carbon dioxide (SC-CO 2 ) as green technology was used to regenerate activated carbons. In this work, response surface methodology was employed to optimize the supercritical regeneration process and to evaluate the effect of the operational parameters including pressure (100–300 bar), temperature (313–333 K), flow rate (2–6 g/min), and dynamic time (30–150 min) on the regeneration yield. The maximum regeneration yield (93.71%) was achieved at 285 bar, 333 K, 4 g/min, and 147 min. Mathematical modeling was done using two one-parameter kinetics models, which agree well with the experimental data. The fitting parameter of the model was obtained by using a differential evolution algorithm. The chemical composition of the substances extracted from the activated carbon was identified by gas chromatography. The results showed that the regeneration of activated carbon by SC-CO 2 can be an alternative method to conventional methods.

Particle size reduction makes drugs more soluble and bioavailable in the body. Researchers are increasingly interested in supercritical fluid processes for the production of micro- and nanoparticles in pharmaceuticals. In this research, gas anti-solvent (GAS), polyvinyl pyrrolidone polymer (PVP), and dimethyl sulfoxide (DMSO) solvent processes were used for the first time to produce aripiprazole (antipsychotic drug) nanoparticles. This specific combination has not been previously reported for aripiprazole and represents the main novelty of the study. The effects of different operating conditions were evaluated using a Box-Behenken design, which also sought to highlight the optimal combinations of conditions to obtain the smallest particle size. The effects of temperature (308, 318, and 328 K), pressure (10, 13, and 16 MPa), and APZ/PVP ratio (1, 5, and 9 w/w) on particle size were investigated. The optimum values of temperature, pressure, and APZ/PVP ratio were 312 K, 16 MPa, and 1w/w, respectively, which resulted in the minimum particle size. FTIR, FESEM, DLS, XRD, DSC, and dissolution rate tests were used to investigate changes in physical - chemical properties. Good results were obtained by reducing the particle size from 104.6 ± 30.1 μm to 389.6 ± 24.2 nm at optimum condition.

The solubility of compounds in supercritical carbon dioxide (SC- CO 2 ) has found crucial significance in the fabrication of micro/nano-scaled drugs. In this research, the solubility of Aripiprazole was measured in SC- CO 2 at various temperatures (308–338 K) and pressures (12–30 MPa). Moreover, the experimental solubility results were correlated with several semi-empirical models (Chrastil, Bartle et al., Kumar & Johnston, Menden-Santiago & Teja, Sodeifian et al., and Jouyban et al.) as well as the modified Wilson model. The molar fraction of the drug in SC- CO 2 varied in the range of 1.830 × 10 - 6 to 1.036 × 10 - 5 . The solubility highly depended on the operating pressure and temperature. The Chrastil (0.994), Jouyban et al. (0.993) and Sodeifian et al. (0.992) models showed the highest consistency with the obtained values. Furthermore, self-consistency tests were performed on the solubility of Aripiprazole in SC- CO 2 . The approximate total enthalpy ( Δ H total ), vaporization enthalpy ( Δ H vap ), and solubility enthalpy ( Δ H sol ) were also calculated.

In this study, rapid expansion of a supercritical solution into a Liquid Solvent (RESOLV) was used for the first time to produce pharmaceutical nanoparticles of Prazosin hydrochloride (PRH). The Taguchi method (robust design) was utilized to design the experiments and ensure obtaining the optimal process conditions. The pressure (15–25 MPa), temperature (308–328 K) and nozzle diameter (300–700 μm) effects on the morphology and size distribution of the resulting particles were also examined. The size of the particles decreased from about 40 μm to the range of (252–418 nm). FTIR, DLS, FESEM, XRD, DSC were used to characterize the primary and processed PRH particles. According to DSC investigations, RESOLV-produced PRH showed lower crystallinity than original PRH.

Building insulators reducing the natural gas required for interior heating or heating load reduction, have a positive impact on energy saving. Paints containing nano-silica aerogel can be applied as façade coatings and building insulators. In this study, the heating load was assessed for a building in a Mediterranean climate. Acrylic paint containing nano-silica aerogel was used as façade coating. The purpose was obtaining the performance of nano-paint on the reduction of heating load for the building. A model was developed to evaluate the amount of building heating load with and without the nano-paint. Nano-coated façade showed reductions in heating load compared to that façade without nano-coating. In addition, a stable heating load requirement was obtained after applying nano-paint, despite changes in the climatic conditions. Thermal insulation and water repellent properties of the paint containing nano-silica aerogel were important to reduce heating load requirement. Therefore, nano-paint containing silica aerogel was a cost-effective modification for façade which introduced a promising passive method to reduce heating load requirement in the buildings.

Low salinity water (LSW) flooding alters rock surface wettability toward more water wetness, and consequently, oil recovery will be increased from a carbonate oil reservoir. Surfactant flooding and polymer flooding enhance oil recovery by oil–water interfacial tension (IFT) reduction and water–oil mobility ratio change, respectively. In this study, a combination of LSW and two non-ionic natural surfactants for enhanced oil recovery was evaluated. Four types of salts (CaCl 2 , MgCl 2 , Na 2 SO 4 , and MgSO 4 ) at different concentrations in distilled water were used to find optimal LSW based on contact angle (CA) reduction. Two non-ionic natural surfactants (a new natural surfactant from Gemini surfactants (GS) family and Tribulus terrestris surfactant) were applied to obtain their optimum concentration based on IFT reduction. The minimum IFT was achieved in 2000 ppm of GS (4.06 mN/m) and 3000 ppm of TTS (6.21 mN/m). Experimental results showed that the presence of GS in low salinity surfactant solution (1000 ppm of MgSO 4 and 2000 ppm GS) is capable to reduce IFT (to 1.02 mN/m) and CA (to 31.25°). Therefore, GS showed good results in IFT improvement and wettability alteration. Finally, the optimal LSS was combined with different concentrations of PHPA polymer and injected into cores. Core flooding results demonstrated 69.7% oil recovery for LSW injection, 82.2% for low salinity GS injection (an increase of 12.5%) and 87.9% for low salinity GS-polymer injection (an increase of 5.7%).

An experimental study was performed to evaluate the colloidal stability of water-based polyvinyl alcohol-functionalized few-layer graphene (water-based PVA–Gr) nanofluids and ethylene glycol-based polyvinyl alcohol-functionalized few-layer graphene (EG-based PVA–Gr) nanofluids. To this end, a liquid-phase exfoliation method was employed for mass production of graphene sheets (Gr). Then, a simple and novel method was introduced to do a direct functionalization of Gr with PVA. Surface functionality groups and morphology of PVA–Gr were analyzed by infrared spectroscopy, Raman spectroscopy and transmission electron microscopy. The results consistently confirmed the formation of PVA functionalities on Gr, while the structure of GNP has remained relatively intact. Then, UV–Vis was employed to investigate the stability of PVA–Gr in water and EG. The easily miscible PVA functionalities formed a great colloidal stability for Gr sheets. As a second criterion for having a promising coolant, thermophysical properties were measured experimentally. The thermal conductivity, density and viscosity of the nanofluids at concentrations of 0.025, 0.05 and 0.1 mass% were experimentally measured. As compared to the base fluid, the water-based PVA–Gr nanofluids show a significant enhancement at different conditions, like representing ~40% enhancement for 0.1 mass% at 40 °C. This simple and efficient procedure may play an important role for mass production of hydrophilic Gr, which be able to disperse in different solvents.