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We present a first-principles-based electron-temperature model that can be used in atomistic calculations. The electron–phonon coupling coefficient in the model is derived from the density of states as a function of electron temperature, and the thermal conductivity of tungsten from our model shows significant improvement over the baseline atomistic calculations in which only ion-thermal contribution to the thermal conductivity is available. The correction to the thermal conductivity also changes damage cascades as cascades cool down more rapidly within our model. The mobility of defects is consequently reduced, leaving more residual damage than the predictions without an electron-temperature model. [ABSTRACT FROM AUTHOR]

"Defect engineering", in which defects are intentionally introduced into metal–organic frameworks (MOFs) with the aim of functionalizing pores and modifying their size distributions, has recently attracted considerable interest. Unfortunately, the surface area of a MOF is inversely proportional to the number of defects, which is the main drawback associated with defect generation; consequently, amorphous MOFs are not very porous. Herein, we prepared Fe-BTC (BTC = 1,3,5-benzenetricarboxylic acid), a defect-rich, amorphous, but porous material, via the post-synthetic metal-ion metathesis (PSMM) of CuZn-HKUST-1 with Fe2+/Fe3+. Zn2+ is relatively weakly bound to BTC3− and is easily replaced by Fe2+/Fe3+, whereas Cu2+ forms stable bonds that maintain the overall MOF structure during the PSMM. Subsequent oxidation of all Fe states to Fe3+ creates significant defects and disorder at metal nodes. While the resulting amorphous Fe-BTC is of similar porosity to Cu-HKUST-1, defects at its metal sites accelerate reactions involving Lewis acid catalysis. [ABSTRACT FROM AUTHOR]

Metal–organic polyhedra (MOPs) are intrinsically porous cage‐like structures; however, they frequently display low porosity due to their agglomeration caused by solvent exchange and removal, which results in the blockage of pore windows. This study presents the unprecedented single‐crystal‐to‐single‐crystal transformation of a cuboctahedral MOP‐OH ([Cu24L24], H2L = 5‐hydroxybenzene‐1,3‐dicarboxylic acid) using a simple solvent exchange from coordinating N,N‐diethylformamide to weakly coordinating chloroform. Following the solvent exchange, the interaction between the cages in the resultant MOP self‐assembly is strengthened while the interaction between the cages and solvents is decreased. The N2 uptake and the surface areas of the MOPs are highly correlated with the cage arrangements: the tightly packed MOPs in chloroform are the most porous among the prepared samples, whereas the loosely packed MOPs are less porous. Scanning electron microscopy reveals that the tight packing of MOPs prevents the crystals from being deteriorating during solvent removal. [ABSTRACT FROM AUTHOR]

In this work, the effect of functional groups on I2 sorption kinetics is investigated using two different types of isostructural metal‐organic frameworks, UiO‐66‐X series (X = H, Br, NO2, NH2, (OH)2, and (COOH)2) and M2(m‐DOBDC) series, (M = Co2+, Mg2+, and Ni2+; m‐DOBDC4− = 4,6‐dioxo‐1,3‐benzenedicarboxylate). Among the UiO‐66‐X series, UiO‐66‐(COOH)2 exhibits the fastest sorption kinetics and the highest sorption capacity due to dipole‐induced dipole interactions between carboxylic acid groups and I2 molecules. In addition, faster I2 chemisorption is observed in M2(m‐DOBDC) because of electrophilic aromatic substitution of m‐DOBDC4− with I2. The I2 sorption mechanisms are further supported by fitting the I2 adsorption kinetics data to pseudo‐first‐order and pseudo‐second‐order kinetic models. [ABSTRACT FROM AUTHOR]

Local order of liquid Ti is studied by ab initio molecular dynamics to address the unique liquid structure factor in experiments reported recently. The present study reveals that the local order of liquid Ti is in the form of fragments of the distorted icosahedral short range order, where the distortion is induced by strong bond order effects. We show that the fragments in the short-bond rich region separated from the background liquid account for the pronounced feature in structure factor of liquid Ti. [ABSTRACT FROM AUTHOR]

The Transient Hot-Wire Method (THWM) was developed to measure the absolute thermal conductivity of gases, liquids, melts, and solids with low uncertainty. The majority of nanofluid researchers used THWM to measure the thermal conductivity of test fluids. Several reasons have been suggested for the discrepancies in these types of measurements, including nanofluid generation, nanofluid stability, and measurement challenges. The details of the transient hot-wire method such as the test cell size, the temperature coefficient of resistance (TCR) and the sampling number are further investigated to improve the accuracy and consistency of the measurements of different researchers. It was observed that smaller test apparatuses were better because they can delay the onset of natural convection. TCR values of a coated platinum wire were measured and statistically analyzed to reduce the uncertainty in thermal conductivity measurements. For validation, ethylene glycol (EG) and water thermal conductivity were measured and analyzed in the temperature range between 280 and 310 K. Furthermore, a detailed statistical analysis was conducted for such measurements, and the results confirmed the minimum number of samples required to achieve the desired resolution and precision of the measurements. It is further proposed that researchers fully report the information related to their measurements to validate the measurements and to avoid future inconsistent nanofluid data. [ABSTRACT FROM AUTHOR]