The geometric structure variation of the nonwetting phase (NWP) in porous media plays a critical role in numerous energy-related processes. This work conducted a series of gas/liquid displacements in three rock cores using high resolution x-ray microcomputed tomography (micro-CT), including two sandstones and a Berea core with different pore architectures. The morphological and topological characteristics of NWP were investigated at the pore scale in a full cycle of primary drainage (PD), main imbibition (MI), and main drainage (MD). It is found that roof and distal snap-off occurred during drainage, resulting in nonwetting (NW) singlets and ganglia. These NW bubbles occupied 10%–20% NWP volume. Both throat snap-off and pore snap-off were observed in MI, which generally occur at a single-pore scale. The effect of viscous force is significant even at a capillary dominant displacement. The trapped NWP during PD can be partially or totally displaced in MI through further snap-off events or viscous remobilization. Due to the temporal and spatial scale diversion in pore scale events, the amplitude of pressure drop fluctuations among PD, MI, and MD is different. The significant difference in NWP characteristics between PD and MD is connectivity, thus leading to hysteresis.

Chinese sweet lily (Lilium davidii var. unicolor), the only edible lily in the world, has high nutritional value. At present, the application of preservation technology is relatively backward, resulting in a large loss of lily. Therefore, the preservation has become one of the key factors limiting the development of the edible lily bulbs industry. This paper reviews the various application of pretreatment and storage technologies for the preservation of lily bulbs. It is considered that irradiation and proper preservative can be used for pretreatment. Vacuum packaging can be used for short-term storage and transportation. Phase temperature storage could be as a long-term storage mode of lily bulbs.

Gravity plays an important role in enhanced oil recovery and groundwater hydrology. A two-dimensional visual homogeneous micromodel was used in this study to describe the role of gravity in displacement processes. A theoretical analysis is proposed for three flow modes, i.e., vertical-upward, vertical-downward, and horizontal displacements, in which water and decane are used for the displacing and the displaced phases, respectively. A relatively compact displacement front was obtained at high flow rates in the three displacement modes, and the front gradually became unstable with a decrease in the flow rate. Compared with horizontal displacement, in vertical-upward displacements, gravity can hinder the evenness of the flow and aggravate the front finger formations at the inlet. This process forces the heavier displacing phase to expand horizontally at the midpoint and weakens the front's fingers. In the vertical-downward displacement process, two states occurred at the same low flow rate: stable flow and unstable flow. Unstable flows occurred more frequently with a decrease in the flow rate. To better understand the role of gravity in displacement, we proposed a theoretical prediction model for the flow state transition of the three displacement modes by combining the capillary force, viscous force, and gravity based on pore-filling events. Finally, to predict the final recovery factor for various displacement modes, four dimensionless formulations were produced using the capillary number, the gravity number, the bond number, and the viscosity ratio.