This article studies buoyancy-driven natural convection of a nanofluid affected by a magnetic field within a square enclosure with an individual conductive pin fin. The effects of electromagnetic forces, thermal conductivity, and inclination angle of pin fin were investigated using non-dimensional parameters. An extensive sensitivity analysis was conducted seeking an optimal heat transfer setting. The novelty of this work lies in including different contributing factors in heat transfer analysis, rigorous analysis of design parameters, and comprehensive mathematical analysis of solution domain for optimization. Results showed that magnetic strength diminished the heat transfer efficacy, while higher relative thermal conductivity of pin fin improved it. Based on the problem settings, we also obtained the relative conductivity value in which the heat transfer is optimal. Higher sensitivity of heat transfer was, though, noticed for both magnetic strength and fin thermal conductivity in comparison to fin inclination angle. Further studies, specifically with realistic geometrical configurations and heat transfer settings, are urged to translate current findings to industrial applications.
Russian Journal of Physical Chemistry A - A new simple and accurate functional form for an attractive parameter α is introduced for Peng–Robinson equation of state. The modified... 相似文献
Stretchable self‐healing urethane‐based biomaterials have always been crucial for biomedical applications; however, the strength is the main constraint of utilization of these healable materials. Here, a series of novel, healable, elastomeric, supramolecular polyester urethane nanocomposites of poly(1,8‐octanediol citrate) and hexamethylene diisocyanate reinforced with cellulose nanocrystals (CNCs) are introduced. Nanocomposites with various amounts of CNCs from 10 to 50 wt% are prepared using solvent casting technique followed by the evaluation of their microstructural features, mechanical properties, healability, and biocompatibility. The synthesized nanocomposites indicate significantly higher tensile modulus (approximately 36–500‐fold) in comparison to the supramolecular polymer alone. Upon exposure to heat, the materials can reheal, but nevertheless when the amount of CNC is greater than 10 wt%, the self‐healing ability of nanocomposites is deteriorated. These materials are capable of rebonding ruptured parts and fully restoring their mechanical properties. In vitro cytotoxicity test of the nanocomposites using human dermal fibroblasts confirms their good cytocompatibility. The optimized structure, self‐healing attributes, and noncytotoxicity make these nanocomposites highly promising for tissue engineering and other biomedical applications. 相似文献
Journal of Thermal Analysis and Calorimetry - High thermal conductivity in phase change materials (PCM) is preferred in thermal energy storage (TES) systems. Carbon additives are considered as... 相似文献
Density functional molecular dynamical calculations have been carried out to explore the effect of silicon impurities on thermodynamic properties of Ga(30). We have obtained 500 distinct low energy equilibrium geometries of Ga(27)Si(3) in order to obtain reliable ground state geometry. The specific heat has been calculated using multiple histogram techniques and compared with that of Ga(30). We demonstrate that silicon impurities have a dramatic effect on the thermodynamic properties of the host cluster. In contrast to Ga(30), the specific heat of Ga(27)Si(3) shows a clear melting peak at ≈500 K, changing the character of Ga(30) from a nonmelter to a melter. 相似文献
Release of heavy metals into water as a result of industrial activity may pose a serious threat to the environment. In this study, the potential of multi-walled carbon nano tubes (MWCNT) to remove Ni2+ cations from aqueous solutions was investigated in a batch reactor under different experimental conditions. The effects on the removal process of conditions such as initial concentration of Ni2+ ions, temperature, and adsorbent mass were investigated. Nickel uptake was quantitatively evaluated by use of the Langmuir, Freundlich, and Dubinin?CKaganer?CRadushkevich isotherm models. For 20?mg/L initial Ni2+ cation concentration, adsorption capacity increased from 8.12 to 11.75?mg/g when the temperature was increased from 25 to 65?°C, an indication of the endothermic nature of adsorption process. In addition, the adsorption equilibrium was well described by the Langmuir isotherm model; maximum adsorption capacity was 17.86?mg/g Ni2+ cations on HNO3-treated MWCNT (t-MWCNT). The results obtained in this study show that adsorption of Ni2+ on t-MWCNT is a spontaneous and endothermic process. By use of second-order kinetic constants and the Arrhenius equation, the activation energy of adsorption (Ea) was determined as 5.56?kJ?mol?1. 相似文献
Monodisperse FePt nanoparticles with average size of 2.4?nm were successfully synthesized via chemical co-reduction of iron acetylacetonate, Fe(acac)3, and platinum acetylacetonate, Pt(acac)2, by 1,2-hexadecanediol as a reducing agent and oleic acid and oleyl amine as surfactant. Then using the seed mediated growth process smaller sized FePt nanoparticles are used as seeds for the growth of larger sized FePt particles and there is no specific limitation to achieve upper size range by this method. In this work, we could synthesize FePt nanoparticles up to 4.0?nm. Monodispersity with relatively narrow size distribution and having the same elemental composition with the atomic percentage of FexPt100?x (x?=?63) are the main advantages of this method. As-made FePt nanoparticles have the chemical disordered face centered cubic structure with superparamagnetic behavior at room temperature. After annealing these particles become ferromagnetic with high magnetocrystalline anisotropy and their coercivity increases with increasing particle sizes and reaches a maximum value of 5,200?Oe for size of 46.5?nm 相似文献
Microfluidic droplet sorting enables the high‐throughput screening and selection of water‐in‐oil microreactors at speeds and volumes unparalleled by traditional well‐plate approaches. Most such systems sort using fluorescent reporters on modified substrates or reactions that are rarely industrially relevant. We describe a microfluidic system for high‐throughput sorting of nanoliter droplets based on direct detection using electrospray ionization mass spectrometry (ESI‐MS). Droplets are split, one portion is analyzed by ESI‐MS, and the second portion is sorted based on the MS result. Throughput of 0.7 samples s?1 is achieved with 98 % accuracy using a self‐correcting and adaptive sorting algorithm. We use the system to screen ≈15 000 samples in 6 h and demonstrate its utility by sorting 25 nL droplets containing transaminase expressed in vitro. Label‐free ESI‐MS droplet screening expands the toolbox for droplet detection and recovery, improving the applicability of droplet sorting to protein engineering, drug discovery, and diagnostic workflows. 相似文献