Nanoengineering-Enhanced Capillary Cooling Achieves Sustained Thermal Protection for Ultra-High Heat Flux and Temperature.

Extreme thermal conditions with heat flux densities exceeding 1 MW m or temperatures reaching up to 1000 °C are prevalent in various situations. However, thermal protection ability depends on specialized materials or is currently limited with existing cooling schemes. Herein, an innovative cooling scheme that relies on evaporation-driven capillary flow, enhanced by nanoengineering-designed porous structures with common materials, is proposed.

NMR Relaxation of Gas Adsorbed in Microporous Material.

NMR relaxometry has been widely applied to characterize fluid confined in porous media because of its versatility, chemical selectivity, and noninvasive nature. Here we extend its usage to gas adsorbed in microporous materials by establishing a new quantitative model based on the molecular level NMR relaxation mechanism revealed by the molecular simulation of a prototypical adsorption system, CH adsorbed in ZIF-8. The model enables new NMR relaxometry-based characterization methods for thermodynamic, dynamic, and structural properties of adsorption systems, as demonstrated and validated by the experiments where the adsorption capacity and self-diffusivity of H, CH, and small alcohols adsorbed in ZIF-8 are deduced from the NMR relaxation data.

Insights into mechanism and modelling of dynamic moisture sorption in dual-porous insulation materials with micro- and nano-scale pores.

Hypothesis: Understanding moisture sorption in porous insulation materials is challenging due to the influence of multiscale pore structures on phase behavior and transport properties. Dynamic moisture sorption in dual-porous materials is likely co-determined by interior micro- and nano-scale pores, and an accurate physical model for predicting moisture evolution can be developed by clarifying the sorption mechanisms.

Experiments: Moisture behavior during the dynamic sorption of dual-porous insulation material is measured by low-field nuclear magnetic resonance (NMR) experiments.

Role of trapped liquid in flow boiling inside micro-porous structures: pore-scale visualization and heat transfer enhancement.

Flow boiling is an important heat dissipation method for cooling high heat flux surfaces in many industrial applications. The heat transfer can be further enhanced by using porous media surfaces due to their high specific surface areas. However, although flow boiling in channels is well understood, the phase-change behavior with the additional capillary effect induced by the porous structures is not well understood, and the design of the porous structures is difficult to avoid dryout and over-temperature accidents.

Evaporation Enhancement of Microscale Droplet Impact on Micro/Nanostructured Surfaces.

The vicinity of the droplet three-phase contact line can be divided into four regions depending on the dominant forces and the liquid film thickness: the absorbed film region, the transition region, the intrinsic meniscus region, and the microconvection region, wherein the transition region has the largest evaporation rate for smaller thermal resistance and weaker intermolecular force between the liquid-vapor interface and the solid surface. On the basis of this perception, micro/nanostructured surfaces (ZnO nanowire surface (ZnO-NW) and copper inverse opal surface (CIO)) were fabricated to enhance the droplet evaporation rate. The precursor film, which can be regarded as the greatly enlarged transition region, was observed on the structured surfaces and promoted the droplet evaporation rate dramatically.

Transpiration cooling with bio-inspired structured surfaces.

Transpiration cooling is considered to be one of the most effective cooling methods for protecting components from ablation in extremely high temperature environments, so improving transpiration cooling efficiency is quite useful in practical applications. Living creatures always have the optimal properties for cooling after long-term evolution. This study proposes a novel transpiration cooling concept using a biomimetic non-smooth surface inspired by the earthworm's rough skin.

Pore-Scale Experimental Investigation of the Effect of Supercritical CO Injection Rate and Surface Wettability on Salt Precipitation.

Injectivity is one of the most important factors to evaluate the feasibility of CO geological storage. Salt precipitation due to the mass of dry CO injected into a saline reservoir may cause a significant decrease in injectivity. However, the coupling effect of injection parameters and reservoir conditions on salt precipitation is not clear.

Improved Method for Measuring the Permeability of Nanoporous Material and its Application to Shale Matrix with Ultra-Low Permeability.

Nanoporous materials have a wide range of applications in clean energy and environmental research. The permeability of nanoporous materials is low, which affects the fluid transport behavior inside the nanopores and thus also affects the performance of technologies based on such materials. For example, during the development of shale gas resources, the permeability of the shale matrix is normally lower than 10 mD and has an important influence on rock parameters.

A promising non-invasive index for predicting liver inflammation in chronic hepatitis B patients with alanine aminotransferase ≤2 upper limit of normal.

Inexpensive and simple non-invasive indexes for predicting liver inflammation are urgently required, but have been poorly studied in chronic hepatitis B (CHB) patients with alanine transaminase (ALT) ≤2 times the upper limit of normal (ULN). A total of 356 CHB patients with ALT ≤2 ULN who presented at Huashan Hospital (n=181) and the First Hospital of Quanzhou (n=175) were enrolled and randomly divided into an experimental assessment cohort (n=238) and validation cohort (n=118) at a ratio of 2:1. Histological analysis of liver tissue was performed to determine the pathological stage according to the Scheuer scoring system.

Exonuclease I and III improve the detection efficacy of hepatitis B virus covalently closed circular DNA.

Background: Hepatitis B virus covalently closed circular DNA (HBV cccDNA) is an important biomarker of hepatitis B virus infection. However, the current methods are not specific and sensitive. The present study aimed to develop a specific and sensitive assay method for the quantification of HBV cccDNA.

Experimental investigation of biomimetic self-pumping and self-adaptive transpiration cooling.

Transpiration cooling is an effective way to protect high heat flux walls. However, the pumps for the transpiration cooling system make the system more complex and increase the load, which is a huge challenge for practical applications. A biomimetic self-pumping transpiration cooling system was developed inspired by the process of trees transpiration that has no pumps.

Effect of Mineral Dissolution/Precipitation and CO Exsolution on CO transport in Geological Carbon Storage.

Geological carbon sequestration (GCS) in deep saline aquifers is an effective means for storing carbon dioxide to address global climate change. As the time after injection increases, the safety of storage increases as the CO transforms from a separate phase to CO(aq) and HCO by dissolution and then to carbonates by mineral dissolution. However, subsequent depressurization could lead to dissolved CO(aq) escaping from the formation water and creating a new separate phase which may reduce the GCS system safety.

Experimental Investigation on the Behavior of Supercritical CO during Reservoir Depressurization.

CO sequestration in saline aquifers is a promising way to address climate change. However, the pressure of the sequestration reservoir may decrease in practice, which induces CO exsolution and expansion in the reservoir. In this study, we conducted a core-scale experimental investigation on the depressurization of CO-containing sandstone using NMR equipment.

Pore-scale visualization on a depressurization-induced CO exsolution.

The pore-scale behavior of the exsolved CO phase during the depressurization process in CO geological storage was investigated. The reservoir pressure decreases when the injection stops or when a leaking event or fluid extraction occurs. The exsolution characteristics of CO affect the migration and fate of CO in the storage site significantly.

Water Droplet Spreading and Wicking on Nanostructured Surfaces.

Phase-change heat transfer on nanostructured surfaces is an efficient cooling method for high heat flux devices due to its superior wettability. Liquid droplet spreading and wicking effect then dominate the heat transfer. Therefore, this study investigates the flow behavior after a droplet touches a nanostructured surface focusing on the ZnO nanowire surface with three different nanowire sizes and two array types (regular and irregular).

Affinity regulation of the NH + HO system by ionic liquids with molecular interaction analysis.

This work proposed using an adequate ionic liquid (IL) to weaken the affinity between NH and HO as a potential solution to the issue of high-energy consumption involved in separating NH gas from liquid HO. Two quaternary phosphonium-based ILs were selected according to an optimized regulation strategy. The regulation effects of the ILs were evaluated by the vapor-liquid equilibrium property of the NH + HO + IL systems, and were compared with the regulation effects of traditional additives.

Numerical Investigation of the Flow Dynamics and Evaporative Cooling of Water Droplets Impinging onto Heated Surfaces: An Effective Approach To Identify Spray Cooling Mechanisms.

Numerical investigations of the dynamics and evaporative cooling of water droplets impinging onto heated surfaces can be used to identify spray cooling mechanisms. Droplet impingement dynamics and evaporation are simulated using the presented numerical model. Volume-of-fluid method is used in the model to track the free surface.

Dropwise Evaporative Cooling of Heated Surfaces with Various Wettability Characteristics Obtained by Nanostructure Modifications.

A numerical and experimental investigation was conducted to analyze dropwise evaporative cooling of heated surfaces with various wettability characteristics. The surface wettability was tuned by nanostructure modifications. Spray-cooling experiments on these surfaces show that surfaces with better wettability have better heat transfer rate and higher critical heat flux (CHF).

CO2 Exsolution from CO2 Saturated Water: Core-Scale Experiments and Focus on Impacts of Pressure Variations.

For CO2 sequestration and utilization in the shallow reservoirs, reservoir pressure changes are due to the injection rate changing, a leakage event, and brine withdrawal for reservoir pressure balance. The amounts of exsolved CO2 which are influenced by the pressure reduction and the subsequent secondary imbibition process have a significant effect on the stability and capacity of CO2 sequestration and utilization. In this study, exsolution behavior of the CO2 has been studied experimentally using a core flooding system in combination with NMR/MRI equipment.