The alloy-design strategy of combining multiple elements in near-equimolar ratios has shown great potential for producing exceptional engineering materials, often known as 'high-entropy alloys'. Understanding the elemental distribution, and, thus, the evolution of the configurational entropy during solidification, is undertaken in the present study using the Al 1.3 CoCrCuFeNi model alloy. Here we show that, even when the material undergoes elemental segregation, precipitation, chemical ordering and spinodal decomposition, a significant amount of disorder remains, due to the distributions of multiple elements in the major phases. The results suggest that the high-entropy alloy-design strategy may be applied to a wide range of complex materials, and should not be limited to the goal of creating single-phase solid solutions.

2The spontaneous imbibition of water and other liquids into gas-filled 3 fractures in variably-saturated porous media is important in a variety of 4 engineering and geological contexts. However, surprisingly few studies have 5 investigated this phenomenon. We present a theoretical framework for 6 predicting the 1-dimensional movement of water into air-filled fractures 7 within a porous medium based on early-time capillary dynamics and 8 spreading over the rough surfaces of fracture faces. The theory permits 9 estimation of sorptivity values for the matrix and fracture zone, as well as a 10 dispersion parameter which quantifies the extent of spreading of the wetting 11 front. Quantitative data on spontaneous imbibition of water in unsaturated 12 Berea sandstone cores were acquired to evaluate the proposed model. The 13 cores with different permeability classes ranging from 50 to 500 mD and 14 were fractured using the Brazilian method. Spontaneous imbibition in the 15 fractured cores was measured by dynamic neutron radiography at the 16 Neutron Imaging Prototype Facility (beam line CG-1D, HFIR), Oak Ridge 17 National Laboratory. Water uptake into both the matrix and the fracture 18 zone exhibited square-root-of-time behavior. The matrix sorptivities ranged 19 from 2.9 to 4.6 mm s -0.5 , and increased linearly as the permeability class 20 increased. The sorptivities of the fracture zones ranged from 17.9 to 27.1 21 mm s -0.5 , and increased linearly with increasing fracture aperture width. The 22 dispersion coefficients ranged from 23.7 to 66.7 mm 2 s -1 and increased 23 linearly with increasing fracture aperture width and damage zone width. 24 Both theory and observations indicate that fractures can significantly 25 increase spontaneous imbibition in unsaturated sedimentary rock by 26 capillary action and surface spreading on rough fracture faces. Fractures 27 also inrease the dispersion of the wetting front. Further research is needed 28 7

We present a neutron-scattering study of the quantum dynamics of molecular hydrogen trapped inside solid C 60. The loading isotherm is shown to deviate significantly from a standard Langmuir response and follows instead an exponential form, increasing from 40% filling at 130 atm to 90% at 700 atm. Diffraction data confirm that the adsorbed molecules are randomly oriented and sit exclusively at the octahedral site. Inelastic neutron scattering clearly shows the ortho to para conversion of the interstitial hydrogen, which occurs via a transition from the Jϭ1 to Jϭ0 rotational levels. The level scheme shows relatively minor deviations ͑on the order of a few percent͒ from the free rotor model with the splitting in the excited level being the same, 0.7 meV, for both H 2 and D 2. In contrast the shift in the overall level, which is shown to depend critically upon zero-point motion is almost three times greater for H 2 than D 2. We also identify the translational modes of the trapped molecules which occur at a much higher energy than would be classically predicted and have an isotopic shift on the order of ͱ2.2. Quantum-mechanical model calculations within the self-consistent harmonic approximation indicate that zero-point motion of H 2 molecules in the ground state play the central role in understanding the experimental results, and in particular the high energy of the translational modes and the magnitude of their isotopic shift. ͓S0163-1829͑99͒03133-1͔