Highlights 1 • Reports a large 3D benchmark study of pore-scale modeling methods 2 • Codes and methods varied widely in complexity and computational 3 demand 4 • Both macroscopic and local measures of flow and solute transport were 5 evaluated 6 • Comparisons were generally favorable among the various methods 7 • Differences observed support method selection depending on problem 8 context 9 Abstract 21Multiple numerical approaches have been developed to simulate porous media fluid flow and solute transport at the pore scale. These include 1) methods that explicitly model the three-dimensional geometry of pore spaces and 2) methods that conceptualize the pore space as a topologically consistent set of stylized pore bodies and pore throats. In previous work we validated a model of the first type, using computational fluid dynamics (CFD) codes employing standard finite volume method (FVM), against magnetic resonance velocimetry (MRV) measurements of pore-scale velocities. Here we expand that validation to include additional models of the first type based on the lattice Boltzmann method (LBM) and smoothed particle hydrodynamics (SPH), as well as a model of the second type, a pore-network model (PNM).The PNM approach used in the current study was recently improved and demonstrated to accurately simulate solute transport in a two-dimensional experiment. While the PNM approach is computationally much less demanding than direct numerical simulation methods, the effect of conceptualizing complex three-dimensional pore geometries on solute transport in the manner of PNMs has not been fully determined. We apply all four approaches (FVM-based CFD, LBM, SPH and PNM) to simulate pore-scale velocity distributions and (for capable codes) nonreactive solute transport, and intercompare the model results. Comparisons are drawn both in terms of macroscopic variables (e.g., permeability, solute breakthrough curves) and microscopic variables (e.g., local velocities and concentrations). Generally good agreement was achieved among the various approaches, but some differences were observed depending on the model context. The intercomparison work was challenging because of variable capabilities of the codes, and inspired some code enhancements to allow consistent comparison of flow and transport simulations across the full suite of methods. This study provides support for confidence in a variety of pore-scale modeling methods, and motivates further development and application of pore-scale simulation methods.

A new large-scale stream temperature model has been developed within the Community Earth System Model (CESM) framework. The model is coupled with the Model for Scale Adaptive River Transport (MOSART) that represents river routing and a water management model (WM) that represents the effects of reservoir operations and water withdrawals on flow regulation. The coupled models allow the impacts of reservoir operations and withdrawals on stream temperature to be explicitly represented in a physically based and consistent way. The models have been applied to the Contiguous United States driven by observed meteorological forcing. Including water management in the models improves the agreement between the simulated and observed streamflow at a large number of stream gauge stations. It is then shown that the model is capable of reproducing stream temperature spatiotemporal variation satisfactorily by comparing against the observed data from over 320 USGS stations. Both climate and water management are found to have important influence on the spatiotemporal patterns of stream temperature. Furthermore, it is quantitatively estimated that reservoir operation could cool down stream temperature in the summer low-flow season (August-October) by as much as 128C due to enhanced low-flow conditions, which have important implications to aquatic ecosystems. Sensitivity of the simulated stream temperature to input data and reservoir operation rules used in the WM model motivates future directions to address some limitations in the current modeling framework.

Pistachio kernel oil (PKO) was prepared by cold‐pressing from raw (RPKO), conventional (CRPKO), and microwave (MRPKO) roasted kernels for Kerman pistachio. Physicochemical properties, bioactive compounds, antioxidant activities, and thermal behaviors of extracted oils were determined in this study. Volatile compounds were tentatively identified and semi‐quantified by headspace solid‐phase micro‐extraction combined with gas chromatography‐mass spectrometry technique. The results showed that there was no significant difference between oil samples for some physicochemical parameters and fatty acid profiles. Roasting treatments caused an increase in total phenolics and antioxidant capacity and a decrease in levels of total tocopherols and chlorophylls. The thermal transition temperatures of the RPKO were −47.15 and −19.85°C for crystallization, and −13.11 and 3.11°C for melting. Among the 43 volatile compounds identified, the major compounds were limonene, α‐pinene, β‐myrcene, hexanoic acid, and nonanal in RPKO. The levels of these compounds decreased after roasting. However, concentrations of pyrazines, furans, and pyrroles increased significantly as a result of roasting, especially for CRPKO. Using a PV of 15 meq/kg oil as a quality criterion, PKO stored in transparent glass bottles after exposed to fluorescent light (720 Lux) and room temperature conditions had an acceptable quality for only 30 days of storage. Practical applications: Pistachios are normally consumed as salted and roasted snacks or as an ingredient in bakery and confectionery products, desserts, and ice‐creams. With the increasing consumption and demand for novel edible oils, the market is expanding and creating space for the production of the pistachio kernel oil. After analyzing the physicochemical characteristics and volatile compounds, roasting treatments may provide additional volatile compounds in the pistachio kernel oil. The research results suggest that cold‐pressed pistachio kernel oil is highly susceptible to photo‐oxidative degradation, and must be stored in containers with light‐barrier properties together with the addition of some appropriate natural antioxidants. Physicochemical properties, volatile compounds, and oxidative stability of pistachio kernel oils obtained from different treated pistachio kernels (raw, conventional, and microwave roasting) by cold pressing method were analyzed. Results indicate that pistachio kernel oil can be produced by the cold pressing technique giving edible quality, which does not require chemical refining, and only a simple filtering or centrifugation to remove suspended plant materials may be needed. Conventional or microwave roasting treatments before pressing did not change the oil specifications significantly.

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