Constraints on the location of the liquid–liquid critical point in water
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Solar-driven interfacial evaporation technologies for food, energy and water
Solar-driven interfacial evaporation technologies use solar energy to heat materials that drive water evaporation. These technologies are versatile and do not require electricity, which enables their potential application across the food, energy and water nexus. In this Review, we assess the potential of solar-driven interfacial evaporation technologies in food, energy and clean-water production, in wastewater treatment, and in resource recovery. Interfacial evaporation technologies can produce up to 5.3 l m–2 h−1 of drinking water using sunlight as the energy source. Systems designed for food production in coastal regions desalinate water to irrigate crops or wash contaminated soils. Technologies are being developed to simultaneously produce both clean energy and water through interfacial evaporation and have reached up to 204 W m–2 for electricity and 2.5 l m–2 h–1 for water in separate systems. Other solar evaporation approaches or combinations of approaches could potentially use the full solar spectrum to generate multiple products (such as water, food, electricity, heating or cooling, and/or fuels). In the future, solar evaporation technologies could aid in food, energy and water provision in low-resource or rural settings that lack reliable access to these essentials, but the systems must first undergo rigorous, scaled-up field testing to understand their performance, stability and competitiveness.
Impact of transboundary water flows on quality-induced water pressure in China
Quality-induced water pressure (P) is gaining increased attention. With the flows of transboundary water, P can be transferred among upstream and downstream regions. Here, we quantified the magnitude of pollutant transmission, and assessed its impact on individual provinces in China. On the annual basis, P was mitigated in 61% of provinces for Chemical Oxygen Demand, 87% for Ammonia Nitrogen, and 84% for Total Phosphorus, while it was intensified for 77% for Total Nitrogen in 2021. The aggregated P were mitigated in 68% of provinces, while intensified in 32% provinces. Furthermore, the monthly assessment has found that the impact of transboundary water on P varies seasonally, generally alleviating in winter and exacerbating in summer. This fluctuation was attributed to the comparatively higher quality of transboundary inflows during winter relative to local water quality. This study provides a scientific foundation for effective water management and quality control.
Brine management with zero and minimal liquid discharge
Zero liquid discharge (ZLD) and minimal liquid discharge (MLD) are brine management approaches that aim to reduce the environmental impacts of brine discharge and recover water for reuse. ZLD maximizes water recovery and avoids the needs for brine disposal, but is expensive and energy-intensive. MLD (which reduces the brine volume and recovers some water) has been proposed as a practical and cost-effective alternative to ZLD, but brine disposal is needed. In this Review, we examine the concepts, technologies and industrial applications of ZLD and MLD. These brine management strategies have current and potential applications in the desalination, energy, mining and semiconductor industries, all of which produce large volumes of brine. Brine concentration and crystallization in ZLD and MLD often rely on mechanical vapour compression and thermal crystallizers, which are effective but energy-intensive. Novel engineered systems for brine volume reduction and crystallization are under active development to achieve MLD and/or ZLD. These emerging systems, such as membrane distillation, electrodialytic crystallization and solvent extraction desalination, still face challenges to outcompete mechanical vapour compression and thermal crystallizers, underscoring the critical need to maximize the full potential of reverse osmosis to attain ultrahigh water recovery. Brine valorization has potential to partially offset the cost of ZLD and MLD, provided that resource recovery can be integrated into treatment trains economically and in accordance with regulations.
Constructing future behavior in the hippocampal formation through composition and replay
The hippocampus is critical for memory, imagination and constructive reasoning. Recent models have suggested that its neuronal responses can be well explained by state spaces that model the transitions between experiences. Here we use simulations and hippocampal recordings to reconcile these views. We show that if state spaces are constructed compositionally from existing building blocks, or primitives, hippocampal responses can be interpreted as compositional memories, binding these primitives together. Critically, this enables agents to behave optimally in new environments with no new learning, inferring behavior directly from the composition. We predict a role for hippocampal replay in building and consolidating these compositional memories. We test these predictions in two datasets by showing that replay events from newly discovered landmarks induce and strengthen new remote firing fields. When the landmark is moved, replay builds a new firing field at the same vector to the new location. Together, these findings provide a framework for reasoning about compositional memories and demonstrate that such memories are formed in hippocampal replay.
Reversibly thermosecreting and convertible lubricative oil-in-water mixtures using multiple hydrogen bonding interactions
Achieving homogeneous oil and water mixing requires thorough droplet dispersions of both liquids. An additional component, such as a surfactant, particle, solvent or ion is normally required to stabilize the small liquid droplets by providing sufficiently low interfacial tensions or strong repulsive forces. Here we show that very stable oil-in-water mixtures can be created even at very high oil volume fractions by building multiple, high-strength hydrogen bonding interactions between water and a biocompatible and biodegradable oil trimethylolpropane trioleate, which make the oil molecules at the contact interface behave as pseudo-surfactants with ultrahigh interfacial activity. The resultant oil microdroplets can be reversibly thermosecreted from the continuous aqueous phase and lead to controllable formation/dissociation and switchable lubrication of the binary liquid mixture owing to the inherent thermal responsiveness of the intermolecular hydrogen bonding. Interestingly, although water is uncovered to possess a relatively poor lubricity, the liquid mixture yields an optimized lubrication that is even exceedingly comparable to pure oil at a water volume fraction as high as 80%.
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