Search

Solar evaporation attracted lots of attention due to its environment-friendly and high efficiency, which is a potential approach to collecting fresh water. Many efforts have been made to improve the evaporation rate in the open space. While the actual water collection rate is far less than the evaporation rate, especially in passive water collection, limiting its practical and scalable applications. In this review, we focus on freshwater collection based on solar evaporation. Firstly, heat and mass transfer behaviors on the evaporation side were summarized to improve evaporation performance, including heat transfer processes in thermal radiation, convection, and conduction; mass transfer processes in water supply, evaporation enthalpy, and salt rejection. Sequentially, subcooling, wettability, and geometry of the condensation side were discussed to improve water collection performance, which should be designed collaboratively with the evaporation side in a confined space. Finally, thermal recovery and electricity generation beyond water collection were also introduced, and some challenges still need to improve in the further for scalable and practical applications, including passive water collection rate, integrated system, and long-term issues. [ABSTRACT FROM AUTHOR]

Despite evidence emphasizing women's responsibility for collecting water in sub-Saharan Africa, more needs to be known about the gender-specific consequences of this obligation, especially in rural Ghana, where water inaccessibility is a persistent issue. Employing a community-based case study, this research aimed to explore the gendered consequences of women's water collection responsibility, using a coupled systems framework. Data were gathered from surveys and focus groups and analysed statistically and thematically, respectively. Key findings highlighted intersecting influences in women's water access and collection difficulties, including distance to water sources, poverty, and health issues. Results revealed that over 50% of women experienced multiple consequences, including physical and psychological injuries (>80%), animal attacks (≤12%), spousal violence (>40%), nutritional challenges (>30%), hygiene problems (>40%), and socioeconomic issues (>50%). Over half faced three to seven intersecting water-related consequences, which intensified their difficulty in accessing and collecting water. Differences were observed across sub-communities. Interestingly, not all men had knowledge of these consequences, highlighting the crucial need to broaden their understanding as part of the solution to ease women's burdens. Addressing sociocultural norms and the various factors influencing access through effective and gendered water management and planning is imperative to alleviate women's burdens and improve equitable access. [ABSTRACT FROM AUTHOR]

This study uses a hybrid concept to propose an optimal textured surface morphology for enhancing water condensation. The natural phenomenon-inspired morphology, which combined different degrees of wettability presented on the surface, documented their advantage in water harvesting compared to untreated surfaces. These superiorities might be explained by the appropriate combination of nucleation and water-driven ability facilitated by the superhydrophobic surrounding area. The uniform condensed droplets are effectively agglomerated to achieve the critical size. The best combination was found on a superhydrophobic-hydrophilic hybrid sample that improved water collection efficiency by up to 50% compared to bare Al. Condensation performance also illustrated an interesting tendency that revealed the great contribution of wettability on hydrophilic dots and the water-driven ability of the high-hydrophobicity area. The results were supported by a theoretical model which predicts the critical volume of a single droplet before it has departed from the surface. The findings reveal a good level of agreement between theory and real-time measurement, demonstrating the potential of combinations of hybrid samples to induce water collection efficiency.

This study uses a hybrid concept to propose an optimal textured surface morphology for enhancing water condensation. The natural phenomenon-inspired morphology, which combined different degrees of wettability presented on the surface, documented their advantage in water harvesting compared to untreated surfaces. These superiorities might be explained by the appropriate combination of nucleation and water-driven ability facilitated by the superhydrophobic surrounding area. The uniform condensed droplets are effectively agglomerated to achieve the critical size. The best combination was found on a superhydrophobic-hydrophilic hybrid sample that improved water collection efficiency by up to 50% compared to bare Al. Condensation performance also illustrated an interesting tendency that revealed the great contribution of wettability on hydrophilic dots and the water-driven ability of the high-hydrophobicity area. The results were supported by a theoretical model which predicts the critical volume of a single droplet before it has departed from the surface. The findings reveal a good level of agreement between theory and real-time measurement, demonstrating the potential of combinations of hybrid samples to induce water collection efficiency. [ABSTRACT FROM AUTHOR]

Surfaces with macro‐scale hydrophilic/hydrophobic regions (conventional Janus mode) are often considered as prime candidates for fog harvesting. However, the water collection efficiency of such surfaces frequently fails to meet the requirements of practical applications due to the occurrence of surface flooding caused by water droplet pinning. Here, an in situ molecular confined modification strategy is proposed to construct upgraded Janus mode for achieving nanoscale drag reduction effect, thereby improving the fog collection efficiency. Specifically, nanoscale hydrophilic sites are designed to effectively reduce the critical volume size required for water droplets to slide off, thus avoiding the surface flooding. Fibers with upgraded Janus mode (PAN‐TO) realize a water collection rate of 4035 mg cm−2 h−1, markedly exceeding that of most materials with conventional Janus mode. Moreover, the high interface bonding strength between hydrophilic sites and the material surface can withstand the impact of water and sand flushing, ensuring the long‐term usability of the material. The applications of PAN‐TO fibers in irrigation and dyeing are demonstrated. This work shows a nanoscale surface engineering proposal for building a next‐generation fibrous fog harvesting device. [ABSTRACT FROM AUTHOR]

About 40% of the world's population suffer from lack of potable water. The paper attempts to fabricate and test a pyramid-shaped solar still having fins. The conventional solar still serves as the baseline, while the finned design incorporates enhanced heat transfer surfaces to improve productivity. Experiments were conducted during three days in the month of March, and the average results are presented. The higher absorber plate, glass plate and water temperatures were recorded between 12 noon and 1 p.m. in the pyramid solar still having fins. The pyramid-shaped solar still model embraces 3 liters of potable water during the day superior to the conventional still. [ABSTRACT FROM AUTHOR]

Solar water evaporation is an emerging technology for drinkable water generation, while it remains a challenge to develop materials and device for efficient water evaporation and collection. Herein, dual‐plasmonic Ti3C2Tx/CuSe two‐dimensional (2D)/2D hybrids are prepared for high‐efficiency solar water evaporation and a hydrophilic device is designed for efficient water collection. The Ti3C2Tx/CuSe hybrids, which monocrystalline CuSe ultrathin nanosheets are chemically bonded with Ti3C2Tx nanosheets, show efficient photothermal conversion owing to the plasmon‐coupling‐induced strong light absorption and fast charge transfer in the 2D/2D interface. By transferring the hybrids on a cotton piece, the Ti3C2Tx/CuSe membrane displays over 95% of solar light absorption, a stable evaporation rate of 1.893 kg m−2 h−1, and solar‐to‐vapor efficiency of 99.13% under one‐sun irradiation. The membrane can also treat water with more than 20 wt% salinity due to the rich microchannel for ion diffusion. Furthermore, a water evaporation device, which the cambered roof is painted with hydrophilic SiO2, is designed for efficient water collection. The treated roof can efficiently reduce the optical loss and transfer the vapor condensation, leading to a high average freshwater generation of 16.4 kg m−2 in a daily (10 h) natural light irradiation, much higher than other reported devices. [ABSTRACT FROM AUTHOR]

In arid areas, the scarcity of rainfall severely limits the growth of plants in the area. In arid sandy deserts, plants survive by deeply rooting to absorb groundwater. In arid gravel soil deserts (Gobi), the gravel in the soil layer limits the growth and water absorption of local plant roots. Therefore, the strategies adopted by local plants to obtain water to sustain life have become crucial. Oxytropis aciphylla Ledeb. is a perennial, strongly xerophytic, cushion-shaped semi-shrub plant widely distributed in arid gravel desert areas. Its plant height is relatively short, its crown width is not large, and its root system is also underdeveloped. There are small and curly pinnate compound leaves and dense hairy fibers on the surface of the leaves. In this study, we focused on the function of leaf surface trichomes by observing the leaf submicroscopic structure, conducting in situ water harvesting experiments, measuring reflectance spectra, and analyzing chloroplast genomes of O. aciphylla leaves. The experimental results indicate that the surface of the leaves of O. aciphylla is densely covered with hair-like fiber arrays, and these hair-like fiber surfaces have micro and nanoscale protrusions. These structures can quickly capture moisture in the air and filter out ultraviolet and infrared rays from the sun, without affecting the normal photosynthesis of the chloroplasts inside the leaves. The important findings of this study are the nanostructures on the surface of the hair-like fibers on the leaves of O. aciphylla, which not only have a water capture function but also reflect light. This has important theoretical significance for understanding how plant leaves in gravel deserts adapt to the environment. [ABSTRACT FROM AUTHOR]

Helical structure is ubiquitous in nature with high-order configuration, specific paths, large superficial areas, providing an approach to bioinspired wettability control. Owing to its special hydrophilic rough surfaces and periodic knot and joint structure, natural spider silk can catch tiny droplets in fog and transport them directionally, sparking scientific interest in bioinspired knotted microfibers to address the risk of water scarcity. To further enhance the water collection ability, a bioinspired helical-groove-modified spindle-knot (HSK) microfiber is continuously fabricated in this work by a simple coating method combined with crack regulation. The formation and morphology can be precisely manipulated by adjusting the drawing velocity and concentration of the coating solution. Compared with smooth spindle-knot microfibers, HSK exhibits greater performances of wetting speed, droplets growth rate, and hanging ability, which can be attributed to the unique helical paths that bring capillary force difference and offer extra three-phase contact line lengths for water collection behavior. The maximum droplet volume is almost 2114 times that of the microfiber knots, which is the highest compared with previous reports. Moreover, HSK microfibers are endowed with repairable wettability, long-term durability, excellent mechanical properties, and flexibility, showing great potential in the realm of applications for large-scale water collection. [ABSTRACT FROM AUTHOR]

Plants and animals that thrive in arid regions utilize the diurnal changes in environmental temperature and humidity to optimize their water budget by combining water-harvesting mechanisms and morphophysiological traits. The Athel tamarisk (Tamarix aphylla) is a halophytic desert shrub that survives in arid, hypersaline conditions by excreting concentrated solutions of ions as droplets on its surface that crystallize into salt crystals and fall off the branches. Here, we describe the crystallization on the surface of the plant and explore the effects of external conditions such as diurnal changes in humidity and temperature. The salt mixtures contain at least ten common minerals, with NaCl and CaSO4·2H2O being the major products, SiO2 and CaCO3 main sand contaminants, and Li2SO4, CaSO4, KCl, K2Ca(SO4)2·H2O, CaMg(CO3)2 and AlNaSi3O8 present in smaller amounts. In natural conditions, the hanging or sitting droplets remain firmly attached to the surface, with an average adhesion force of 275 ± 3.5 µN measured for pure water. Rather than using morphological features of the surface, the droplets adhere by chemical interactions, predominantly by hydrogen bonding. Increasing ion concentration slightly increases the contact angle on the hydrophobic cuticle, thereby lowering surface wettability. Small amounts of lithium sulfate and possibly other hygroscopic salts result in strong hygroscopicity and propensity for deliquescence of the salt mixture overnight. Within a broader context, this natural mechanism for humidity harvesting that uses environmentally benign salts as moisture adsorbents could provide a bioinspired approach that complements the currently available water collection or cloud-seeding technologies. [ABSTRACT FROM AUTHOR]

Simple Summary: Plants in arid areas have evolved narrow linear leaves or degenerated into cone-shaped spines to reduce solar radiation and excessive water loss. We have demonstrated for the first time the widely distributed sub-tree species of Elaeagnus angustifolia in arid areas. E. angustifolia has large- and medium-sized leaves, and the surface of the leaves is covered with umbrella-shaped ratchet trichomes that can capture moisture in the air and reflect solar radiation. This study reveals that the trichomes on the E. angustifolia leaf surface can collect water and reflect light, which provides a reference for bionic development and research in atmospheric water harvesting, seawater desalination, energy management, microfluidic control, and daytime radiative cooling. Leaves are essential for plants, enabling photosynthesis and transpiration. In arid regions, water availability limits plant growth. Some plants, like Elaeagnus angustifolia, a sandy sub-tree species widely distributed in arid and semi-arid regions, have unique leaf structures to reduce water loss and solar radiation. Here, we describe the leaves of Elaeagnus angustifolia L., with special functioning trichomes. Through leaf submicroscopic structure observation, in situ water collection experiments, photosynthesis measurements, and reflection spectrum analysis, we investigated E. angustifolia leaves, focusing on their functioning trichomes. These trichomes capture water vapor, reflect UV and NIR light, and possess a 3D interface structure composed of 1D and 2D structures. The 1D conical structure captures water droplets, which are then gathered by the radial conical structure and guided towards the stomata through wedge-shaped grooves on the 2D umbrella structure. The trichomes also reflect sunlight, with micropapillae reflecting UV light and the umbrella structure reflecting NIR light. These mechanisms reduce leaf temperature, respiration, and water transpiration, protecting against solar radiation damage. This study provides insights into water collection and light-reflection mechanisms, revealing adaptive strategies of plants with large leaves in arid regions. [ABSTRACT FROM AUTHOR]

In recent studies, Thermo-Electric Coolers (TEC) have been utilized for dehumidification purposes, which is mainly based on the extraction of moisture from humid atmospheric air. The reviewed literature showed that the rate of water collection from the TEC-based system can be affected by various parameters such as the module’s input voltage, the heat sink orientation, and tilt angles. In this research, the analysis of variance (ANOVA) was used to examine the significance of these factors and their interaction within the system on the TEC-based dehumidification system. Four levels were investigated for both, the Peltier’s input voltage and the rotation angle, and three levels for the tilt angle. This study indicated the significance of the studied factors and their interactions within the dehumidification system along with performing an overall numerical optimization. The experiments were conducted under the same working conditions in an enclosed environment to minimize errors. According to the overall numerical optimization, which was validated experimentally, the optimum system performance was predicted to be obtained at approximately 6.8V Peltier input volt, 65° rotation angle, and 90° tilt angles, with predicted optimum productivities of 0.32278 L/kWh and 13.03 mL/hr. For the same set of parameters, the variation between the experiment and the numerical optimization was less than 4%. The experiments show that when optimizing water collection rates for thermoelectric cooling heat sinks​ under high humidity conditions, the orientation of the heat sink should be considered.

Droplet impact affects water collection, which is the key to investigating the icing process on an aero-engine spinner. Different from a stationary spinner, droplet impact is affected by Coriolis acceleration and centrifugal acceleration on rotating aero-engine spinners, showing different impact dynamics. Based on the Eulerian method, using the rotating coordinate system we numerically investigated droplet impact characteristics on three different shapes of aero-engine spinners using ANSYS Fluent. The results indicate that the impact area covered all the windward surface on the conical spinner, and only covered the windward surface prior to the impingement limit of the elliptical spinner and the coniptical spinner. The sensitivity of water collection to inflow velocity declined in the order of coniptical the spinner, the elliptical spinner, and the conical spinner. In addition, the elliptical region could effectively improve aerodynamic performance, as shown in a lower total pressure loss through the spinner. This work is relevant to the anti-icing system of a rotating aero-engine spinner. [ABSTRACT FROM AUTHOR]

The COVID-19 pandemic showed us how fragile cities are when dealing with this phenomenon. The lack of green areas, high pollution levels, and human overpopulation contributed to the increase of the urban heat island effect and proved to be the perfect ingredients for the spread of the virus that changed, perhaps forever, our ways of living inhabiting. The consequences were even more dramatic for the inhabitants of informal neighbourhoods, as these exacerbated existing problems related to economic instability and low food and water security. This paper proposes using Nature-Based Solutions to mitigate and adapt to climate change and increase access to water in informal settlements. The research study focused on analysing two technologies, the Blue-Green roof and Rain Garden, developing a prototype for each one. Considering that the practice of self-building characterises spontaneous settlements, the modules were conceived to be built by the inhabitants using recycled materials. These low-tech strategies improve indoor thermal comfort, facilitate the storage of filtered rainwater for domestic use and provide access to affordable food through domestic scale cultivation. Implementing these solutions in marginalised neighbourhoods could also empower residents to face challenges related to Global Warming, such as runoffs generated by heavy precipitations, and improve hygienic conditions to prevent the spread of diseases.

[Display omitted] • Hydrophilic/hydrophobic dual metal–organic frameworks Janus network is prepared on bio-inspired leaf vein (LV) structure for fog harvesting. • The integrated strategy by mimicking cactus needles, Janus wettability and bionic LV network in fog collection can be regulated by the multi-cooperation theory. • The Janus LV devices yields a high fog collection efficiency and intelligent interfacial materials. The leaf vein (LV) structure is an evolutionarily optimized quasi-fractal network responsible for efficient capture and transport of water with minimum energy consumption. For the first time, a bio-inspired dual-metal organic framework (MOF) functionalized LV network was proposed for water collection. Two MOFs with distinct wettabilities and microstructures are in-situ grown on opposite side of a metallic LV network, yielding a Janus LV (J-LV) network. The integrated strategy by mimicking cactus needles, Janus structures and bionic LV network in water harvesting can be regulated by the multi-cooperation theory in the processes of droplet caption, transport and collection. As such, the fog collection efficiency of J-LV devices can reach 1.23 ± 0.07 g cm-2h−1, which is a 292.9 % increase compared to that of the bare LV. Moreover, the J-LV has excellent interfacial floatability, showing capability of not only carrying objects weighing 149.5 times its own weight while keeping afloat, but also attaching firmly to the air–water interface under harsh airflow. We demonstrate that such Janus quasi-fractal LVs networks by in-situ dual-MOF growth will inspire new insight for designing highly efficient fog water collectors and intelligent Janus interface materials. [ABSTRACT FROM AUTHOR]

In arid areas, the scarcity of rainfall severely limits the growth of plants in the area. In arid sandy deserts, plants survive by deeply rooting to absorb groundwater. In arid gravel soil deserts (Gobi), the gravel in the soil layer limits the growth and water absorption of local plant roots. Therefore, the strategies adopted by local plants to obtain water to sustain life have become crucial. Oxytropis aciphylla Ledeb. is a perennial, strongly xerophytic, cushion-shaped semi-shrub plant widely distributed in arid gravel desert areas. Its plant height is relatively short, its crown width is not large, and its root system is also underdeveloped. There are small and curly pinnate compound leaves and dense hairy fibers on the surface of the leaves. In this study, we focused on the function of leaf surface trichomes by observing the leaf submicroscopic structure, conducting in situ water harvesting experiments, measuring reflectance spectra, and analyzing chloroplast genomes of O. aciphylla leaves. The experimental results indicate that the surface of the leaves of O. aciphylla is densely covered with hair-like fiber arrays, and these hair-like fiber surfaces have micro and nanoscale protrusions. These structures can quickly capture moisture in the air and filter out ultraviolet and infrared rays from the sun, without affecting the normal photosynthesis of the chloroplasts inside the leaves. The important findings of this study are the nanostructures on the surface of the hair-like fibers on the leaves of O. aciphylla, which not only have a water capture function but also reflect light. This has important theoretical significance for understanding how plant leaves in gravel deserts adapt to the environment.

The Sacachún commune in Ecuador currently faces a lack of water for its agricultural development; this reduces its possibilities of socio-economic development and causes migration to urban areas. This research proposes a presa colinar (hill dam) design that uses ancestral knowledge and classic engineering techniques to promote water use during the dry season in semi-arid regions. The methodology consisted of: (i) a systematic compilation of the ancestral structures used for water planting and harvesting in Ibero-American; (ii) selecting an appropriate place to build the hill dam; (iii) the dam's body design; (iv) and creating a proposal for agricultural water use. The results helped define a good location for the hill dam implementation. In addition, a 10 m high and 40 m wide earthen dam was designed, with a storage capacity of 114,341 m3, extending agriculture to 7.5 ha through a polyculture system of six different plants. The embankment has a cofferdam located downstream, which provides stability in static and pseudo-static conditions. In addition, the dam slopes have a 2:1 ratio, and a spillway channel and filter drain were dimensioned to protect the dam. [ABSTRACT FROM AUTHOR]

Copyright of Iranian Journal of Agricultural Economics & Development Research (IJAEDR) is the property of University of Tehran and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Interfacial solar vapor generation is a promising technology for alleviating the current global water crisis, and the evaporation rate and efficiency have approached the theoretical limit. In a practical interfacial evaporation water purification system, the collection rate of purified water is typically lower than the evaporation rate. Passive collection devices based on gravity are susceptible to environmental influences and exhibit low collection efficiency, while active collection devices consuming external energy suffer from complex device systems and extra energy consumption. Given that both collection devices are nonselective and unable to distinguish contaminants mixed in the vapor, bionic membranes with autonomously passive and unidirectional water transfer capacity are developed through 3D printing for efficient water collection. More importantly, the bionic membranes are capable of high-speed water transportation without the need for external energy or gravity drive and liquid-selective transportation for separating oily pollutants from the collected products. The directional transport property facilitates the modular assembly of the bionic membrane, extending its application to practical large-scale solar-driven seawater desalination systems.

Leaves are essential for plants, enabling photosynthesis and transpiration. In arid regions, water availability limits plant growth. Some plants, like Elaeagnus angustifolia, a sandy sub-tree species widely distributed in arid and semi-arid regions, have unique leaf structures to reduce water loss and solar radiation. Here, we describe the leaves of Elaeagnus angustifolia L., with special functioning trichomes. Through leaf submicroscopic structure observation, in situ water collection experiments, photosynthesis measurements, and reflection spectrum analysis, we investigated E. angustifolia leaves, focusing on their functioning trichomes. These trichomes capture water vapor, reflect UV and NIR light, and possess a 3D interface structure composed of 1D and 2D structures. The 1D conical structure captures water droplets, which are then gathered by the radial conical structure and guided towards the stomata through wedge-shaped grooves on the 2D umbrella structure. The trichomes also reflect sunlight, with micropapillae reflecting UV light and the umbrella structure reflecting NIR light. These mechanisms reduce leaf temperature, respiration, and water transpiration, protecting against solar radiation damage. This study provides insights into water collection and light-reflection mechanisms, revealing adaptive strategies of plants with large leaves in arid regions.

Functionality and stimuli‐response of natural and artificial elastomeric materials depend significantly on the morphology of their surfaces. Structural transformability and tunable responsiveness of wrinkles on elastomeric materials can enable numerous applications in flexible electronics, optics, and adhesives. Currently existing fabrication techniques rely on sophisticated instrumentation, complex experimental setups, and expensive reagents. These methods are limited in terms of mechanical robustness of the wrinkles produced. Here, a simple, inexpensive, scalable, and reproducible strategy, making use of buckling instability for the creation of soft surface wrinkles on polydimethylsiloxane (PDMS), is presented. PDMS with lower elastic modulus is spin‐coated onto a mechanically stretched film of PDMS with a higher elastic modulus. Thermal curing followed by the release of prestrain resulted in the formation of wrinkles in the top layer of the PDMS. The hydrophobic soft surface wrinkles with compositional homogeneity exhibit efficient fog water collection and triboelectric charge generation useful for the preparation of triboelectric nanogenerator devices. Furthermore, the substrates show high mechanical stability and mechanoresponsive optical behaviors. The simplicity and general applicability of the method presented here is expected to establish a promising pathway toward the formation of soft wrinkles in other elastomeric systems also, facilitating important applications in various fields. [ABSTRACT FROM AUTHOR]

In this study, a needle–cylinder electrostatic precipitator with a water cooling system was designed to enhance the harvest of atmospheric water in wet flue gas. The effects of flow rate, temperature and particles on the collection of fog droplets were investigated. Meanwhile, the energy efficiency of water collection was analyzed at different voltages. The results show that the current decreases with the increase of air relative humidity under the same voltage, and the breakdown voltage increases obviously. Concurrently, by appropriately reducing the wet flue gas flow velocity, the residence time of fog droplets in the electric field can be increased, fully charging the droplets and improving the water collection efficiency. Moreover, experiments revealed that through decreasing the flue gas temperature, both the water collection rate and energy efficiency can be improved. In addition, the presence of particles in wet gas can improve the water collection rate by 5~8% at different discharge voltages. Finally, based on energy efficiency analysis, with the increase of voltage, although the water collection rate increased, the energy efficiency decreased. [ABSTRACT FROM AUTHOR]

Water collection from mist is a potential solution to water scarcity, which is a critical issue worldwide. In this paper, laser interference ablation assisted with stearic acid immersion has been used to achieve synergistic modulation of dynamic adhesion and static wettability for water collection on fluorine-free aluminum alloy surface. The research demonstrates that there is an optimal balance point between dynamic adhesion and static wettability for water collection. This optimal point shifts toward low dynamic adhesion at the high misting rate due to the flooding on metastable surfaces with high dynamic adhesion. In addition, wetting transition induced by tilting is observed on metastable surfaces. The good stability of the proposed fluorine-free surface has been demonstrated by the long-term water collection and long periods of immersion in water. This work can provide theoretical inspiration and a scalable preparation method for green and stable water collection strategies. [Display omitted] [ABSTRACT FROM AUTHOR]

Designing hybrid surfaces with superhydrophilic and superhydrophobic properties represents a promising approach for fog collection. Inspired by the adhesive properties of mussel proteins, a polydopamine (PDA) film was firmly attached to a brass surface through a combination of chemical etching and spontaneous dopamine polymerization. By harnessing the exceptional characteristics of PDA as a "double-sided adhesive," a hybrid surface with mixed wettability was created using a facile and cost-effective method involving SiO 2 and TiO 2 nanoparticles (NPs). The TiO 2 NPs served as the hydrophilic sites for water capture, while the SiO 2 NPs acted as the hydrophobic region to induce water droplet rolling. The resulting hybrid surface exhibited a significant improvement in water collection rate, measuring approximately 1.182 g/cm2/h, which was 1.84 times higher than that of the bare brass surface. This demonstrated a remarkable enhancement in fog collection capacity. Moreover, the hybrid surface demonstrated commendable corrosion resistance and remarkable durability, indicating its great potential for widespread application in practical scenarios. [Display omitted] [ABSTRACT FROM AUTHOR]

Copyright of Acta Materiae Compositae Sinica is the property of Acta Materiea Compositae Sinica Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The COVID-19 pandemic showed us how fragile cities are when dealing with this phenomenon. The lack of green areas, high pollution levels, and human overpopulation contributed to the increase of the urban heat island effect and proved to be the perfect ingredients for the spread of the virus that changed, perhaps forever, our ways of living inhabiting. The consequences were even more dramatic for the inhabitants of informal neighbourhoods, as these exacerbated existing problems related to economic instability and low food and water security. This paper proposes using Nature-Based Solutions to mitigate and adapt to climate change and increase access to water in informal settlements. The research study focused on analysing two technologies, the Blue-Green roof and Rain Garden, developing a prototype for each one. Considering that the practice of self-building characterises spontaneous settlements, the modules were conceived to be built by the inhabitants using recycled materials. These low-tech strategies improve indoor thermal comfort, facilitate the storage of filtered rainwater for domestic use and provide access to affordable food through domestic scale cultivation. Implementing these solutions in marginalised neighbourhoods could also empower residents to face challenges related to Global Warming, such as runoffs generated by heavy precipitations, and improve hygienic conditions to prevent the spread of diseases. [ABSTRACT FROM AUTHOR]

At present, the shortage of fresh water resources has become a serious problem that human beings have to face. Especially in some arid areas, water shortage has threatened human existence. The discovery that some organisms can survive in extremely arid areas by trapping water in fog has inspired research into bionic water harvesting materials. The emergence of such biomimetic materials offers a potential strategy for tackling the freshwater crisis. This paper reviews the mechanism of some organisms' water collecting function and special liquid handling ability and the research progress of biomimetic fog‐collecting materials. In addition, the bionic water collecting materials which creatively combine the advantages of various organisms are introduced in detail. It is hoped that these innovative combinations can bring inspiration to the design of fog collecting materials in the future. Finally, the research and development prospects of materials inspired by multiorganisms are prospected. [ABSTRACT FROM AUTHOR]

Many animals have been documented to collect and subsequently transport water for several purposes besides self‐hydration. However, there are few examples where this process involves the use of external body surfaces. Herein, we report on a long‐jawed spider from the Tetragnatha genus using its enlarged jaws (chelicerae) to collect water. Field observations revealed a long‐jawed spider descending on a silk line to the surface of a body of water and collecting a large droplet of water between its jaws, which was subsequently transported to a prey item wrapped in silk within its web. As spiders feed via extra‐oral digestion, we hypothesize that this water droplet was collected to replenish water lost during a previous feeding event or to rehydrate current prey to aid in nutrient extraction and consumption. While the enlarged jaws of spiders in this genus serve in feeding and mating, our observation suggests they can also be exploited for carrying liquids. This appears to be the first documented case of water foraging and subsequent external transport among spiders, revealing a novel behaviour in this group. [ABSTRACT FROM AUTHOR]

Common Portland cement was used as the main matrix material and cementations material, fly ash as admixture, 30 % wt hydrogen peroxide as foaming agent and other additives to prepare cement based condensate porous material. The optimum amount of foaming agent was determined by water absorption and release experiment, and the metal fiber was added to the material to enhance the water collecting performance. As the amount of foaming agent increased, water absorption increased, water release rate decreased, the optimum content of foaming agent was 2.73 %, the material had better water absorption and water release performance, and the addition of metal fiber could obviously improve the water collection performance of cement-based porous condensate material. [ABSTRACT FROM AUTHOR]

[Display omitted] • Nowadays, freshwater crisis seriously challenges human survival and development. • Solar desalination is promising in collecting clean water, but only feasible in regions with available surface water. • Atmospheric water harvesting is independent of surface water but requires high humidity and complex equipments. • In this study, efficient water harvesting from desert soil in very dry regions is achieved via interfacial solar heating under natural sunlight. • The portable and scalable water harvesting device, composed of merely a thin layer of activated carbon, a commercially available polyethylene film and a water container, could collect 1.13 kg of clean water per square meter of desert soil per day. Freshwater crisis seriously challenges human survival and development, especially in arid regions. Solar-driven interfacial evaporation has recently received tremendous interest for collecting clean water, yet is only feasible in regions with available surface water. Atmospheric water harvesting is independent of surface water but requires high RH, additional energy input and complex equipment. Here, we demonstrate efficient water harvesting from desert soil in very dry regions (air RH < 10%, soil moisture content < 3%) via interfacial solar heating under natural sunlight. The water harvesting device, composed of merely a thin layer of activated carbon (for interfacial solar heating on soil surface), a commercially available polyethylene film (for vapor condensation and water transport) and a water container, could collect 1.13 kg of clean water per square meter of desert soil per day (8 h), i.e., 0.53 kg of clean water per kilogram of activated carbon per hour, under a solar flux of 0.26–0.55 kW m−2. Besides, the soil water harvesting system is very portable, low-cost and scalable. This work opens up a new sustainable approach for solving the freshwater crisis in arid and impoverished regions. [ABSTRACT FROM AUTHOR]

Copyright of China Pulp & Paper is the property of China Pulp & Paper Magazines Publisher and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Droplet impact affects water collection, which is the key to investigating the icing process on an aero-engine spinner. Different from a stationary spinner, droplet impact is affected by Coriolis acceleration and centrifugal acceleration on rotating aero-engine spinners, showing different impact dynamics. Based on the Eulerian method, using the rotating coordinate system we numerically investigated droplet impact characteristics on three different shapes of aero-engine spinners using ANSYS Fluent. The results indicate that the impact area covered all the windward surface on the conical spinner, and only covered the windward surface prior to the impingement limit of the elliptical spinner and the coniptical spinner. The sensitivity of water collection to inflow velocity declined in the order of coniptical the spinner, the elliptical spinner, and the conical spinner. In addition, the elliptical region could effectively improve aerodynamic performance, as shown in a lower total pressure loss through the spinner. This work is relevant to the anti-icing system of a rotating aero-engine spinner.

Effective sweat management fabric for sportswear facilitates sweat removal from the skin and elevates the comfort for human. However, when the body is in a strong hot and humid environment or after strenuous exercise, the sweat management fabric will be totally wetted and saturated quickly. As a result, excess sweat cannot be absorbed effectively by the garment, which creates obvious stickiness and heaviness. In this paper, a directional water transport and collection multilayered knitted fabric (DWTCF) is prepared by plasma pretreatment technology and screen coating. The treelike water transport network inspired from nature is designed in order to drive the liquid flow along the channels. By surface modification, branched hydrophilic flow paths are fabricated, and other regions are hydrophobic. As a demonstration, DWTCF has been injected with water to observe the liquid transport behavior. During the experiment, 76.7% liquid is collected by DWTCF, but there is just 0.06% collected by an ordinary knitted fabric. The weight increase of the ordinary fabric is 555.4% larger than that of DWTCF. Specifically, DWTCF utilizes the wetting and pressure-gradient-induced interfacial tension as well as the gravitational effect to facilitate the fluid motion along the hydrophilic channel, in addition to the capillarity present in the fabric structure. This study provides a new idea to develop directional water transport and collection fabric to solve the moisture absorption saturation problem of the fabric, especially for conditions requiring intense sweating.

Vapor condensation and condensate collection play a crucial role in solar water desalination, which is a promising solution to the shortage of freshwater. However, the currently used condensers based on thermal conduction and/or convection cooling are limited in cooling power for vapor condensation, whilst their surface wettability requires appropriate modulation to facilitate condensate collection. In this work, we achieve efficient water collection via using a wettability and spectral selectivity engineered coating comprising hydrophobic SiO2 and hydrophilic TiO2 nanospheres at an optimized weight ratio. The tuning of surface wettability promotes a dropwise collection mode, leading to maximized droplet harvesting performance of 1047 mg·cm−2·h−1. Further, the coating can spontaneously cool itself by reflecting ~90% of the incident sunlight whilst emitting >95% of thermal infrared rays, leads to a daytime sub-ambient temperature drop of 7 °C. Hence, under an ultra-humid condition that mimics a solar water-purification system, the coating that integrates daytime radiative cooling with dropwise collection demonstrates an excellent water production rate, which is superior to those of the hydrophilic surface and the surface with restricted radiative cooling access to the sky. Moreover, the coating comprising TiO2 photocatalyst can recover its wettability through the photocatalytic degradation of adsorbed oily dirt pollutants.

In recent years, the ability of superhydrophilic/superhydrophobic bioinspired heterogeneous wettability (SSBHW) surfaces to collect freshwater has gained significant attention due to their potential to mitigate water scarcity. Inspired by nature's creatures, this paper presents an SSBHW surface that can efficiently collect freshwater resources from the atmosphere, drawing inspiration from cactus needles and spider silk spindles. The superhydrophobic (SHO) surface was prepared by wet etching and low surface energy modification on copper surface. Based on the SHO surface, the superhydrophilic (SHI) patterns consisting of spindle-shaped and wedge-shaped were constructed by laser ablation. The prepared SHI pattern was not only trapped airborne droplets but also enabled the directional transport of droplets. To enhance the efficiency of water collection, the smaller spindle-shaped pattern spacing in the SHO region was designed, which help to transport the condensed water quickly towards the SHI region because of the surface energy gradient force. The synergistic effect between the advantages offered by the SHO and SHI surfaces results in a significant improvement in water collection efficiency. The water collection efficiency of the SSBHW surface is 870 mg cm−2 h−1, which is 3.32 and 2.2 times higher than that of the SHI and SHO surfaces, respectively. In addition, the mechanism of enhancement of the moisture harvesting behavior of inhomogeneous wettable surfaces was analyzed. This work provides a new strategy for the study of catchment surfaces, making it an effective solution for obtaining fresh water resources in arid regions. [Display omitted] • The SSBHW surface were prepared based on cactus needles and spider silk spindle konts. • Superhydrophilic microchannels achieve rapid droplet transportation. • The smaller spindle spacing reduces the condensation time of the droplets on the superhydrophobic surface. • The combination of spindle-shaped and wedge-shaped surfaces effectively improves water collection efficiency. [ABSTRACT FROM AUTHOR]

In (semi-)arid regions, harvesting fog and dew can become a complementary solution to traditional water supply. In the Atacama region, a territory of key and water-dependent economic activities, both fog and dew are driven by the advection of marine moisture from the Pacific. Still, little is described regarding the dynamics and water potential of these events. In this study, we analyze the spatiotemporal variability of fog and dew in the Atacama Desert to assess the potential of non-rainfall atmospheric water harvesting. Our research strategy combines three methods to achieve a comprehensive understanding of these phenomena: a satellite-spatial analysis of fog and low cloud frequencies; a thermodynamic characterization of the fog cloud vertical structure; and an observational analysis of fog and dew water collection. Our findings reveal that fog is a regular phenomenon in the area, occurring from 3% to 20% of the year. We estimate that fog cloud reaches 50 km inland and up to ∼1100 m ASL, covering a vast territory where it can be harvested. Fog and dew represent 72% and 28% of the total collected atmospheric water (∼0.2 L m−2 day−1). Both fog and dew represent a complementary natural water source with multiple uses for local industries. • Fog and low clouds in the Atacama are related to the topography shape combined with marine boundary layer height. • Fog and dew represent 72% and 28% of the total collected atmospheric water. • Fog and dew represent a complementary natural water source with multiple uses for local industries. [ABSTRACT FROM AUTHOR]

Abstract Background Mental disorders, particularly depression and post-traumatic stress disorder, are common long-term psychological outcomes in emergency contexts arising from conflicts, natural disasters, and other challenging environmental conditions. In emergencies, people suffer not only from the lack of external resources such as drinking water and food but also from poor mental health. Mental disorders can substantially impair daily activities in vulnerable individuals. However, water, sanitation, and hygiene (WASH) behaviors are daily activities that require effort, time, and strong internal motivation. Therefore, questions arise: whether there is a relationship between mental health and safe water behaviors, and if so, whether the motivational drivers of these behaviors are affected by mental health. Methods Our cross-sectional study conducted face-to-face interviews with 638 households in rural Malawi. We used a quantitative questionnaire based on the risks, attitudes, norms, abilities, and self-regulation (RANAS) approach to measure motivational psychosocial factors. Mental health was assessed using the validated Chichewa version of the Self-Reporting Questionnaire (SRQ-20). Results. Almost a third of the respondents reported poor mental health. We found significant negative association between mental health and self-reported safe water collection (p = .01, r = −.104) but not between safe water transportation and storage behavior. The moderation analysis revealed significant interaction effects of mental health with some psychosocial factors and therefore on WASH behaviors. Poor mental health changed the influence of three psychosocial factors—perceived others’ behavior, commitment, and remembering—on safe drinking water collection behavior. The influence on water transportation and storage behavior of the perceived severity of contracting a disease, the belief that transporting and storing water requires substantial effort, and others’ approval depended on the mental health condition of the respondent. Conclusions These results imply that populations with a significant proportion of individuals with poor mental health will benefit from interventions to mitigate mental health before or parallel to behavioral change interventions for WASH. Specific population-level interventions have been shown to have a positive effect on mental well-being, and they have been successfully applied at scale. This research is especially relevant in emergency contexts, as it indicates that mental health measures before any WASH interventions will make them more effective.

In this study, a needle–cylinder electrostatic precipitator with a water cooling system was designed to enhance the harvest of atmospheric water in wet flue gas. The effects of flow rate, temperature and particles on the collection of fog droplets were investigated. Meanwhile, the energy efficiency of water collection was analyzed at different voltages. The results show that the current decreases with the increase of air relative humidity under the same voltage, and the breakdown voltage increases obviously. Concurrently, by appropriately reducing the wet flue gas flow velocity, the residence time of fog droplets in the electric field can be increased, fully charging the droplets and improving the water collection efficiency. Moreover, experiments revealed that through decreasing the flue gas temperature, both the water collection rate and energy efficiency can be improved. In addition, the presence of particles in wet gas can improve the water collection rate by 5~8% at different discharge voltages. Finally, based on energy efficiency analysis, with the increase of voltage, although the water collection rate increased, the energy efficiency decreased.

Abstract Water collection from fog has received much attention to meet the challenges of scarcity of clean drinking water in desert and arid regions. Currently, solar‐thermal technology is being used as an efficient, sustainable, and low‐cost method for water desalination to produce clean water. To collect the clean water, in recent years, most researchers have designed the structure of water collection surfaces. However, the heat released during the liquefaction process of droplets has an adverse effect on the condensation of droplets, and thus affecting the water collection efficiency. Here, in order to improve water collection efficiency, a radiative cooling layer is introduced on the back of the collection surface to dissipate the heat released during droplet liquefaction. The radiative cooling layer, consisting of poly(vinylidene fluoride‐co‐hexafluoropropene) embedded with SiO2 and CaMoO4 nanoparticles, can theoretically cool 18.1 °C below the ambient temperature in the daytime. With the addition of cooling coating on the back of the water collection surface, the water harvesting efficiency can be increased by 43–52%. The developed water harvesting device may provide a new pathway to the efficient collection of fresh water.

The corrosion protection performance of commercial organic coatings over Stainless Steel (304 L) was investigated in highly acidic media. Three coatings were applied by air spraying and subsequently evaluated for their performance against chemical corrosion by concentrated H2SO4, HNO3, and HCl in terms of % mass loss. Open current potential (OCP) and potentiodynamic polarization (PD) measurements were performed. The water condensation properties of the coatings were monitored for their evaluation as potential protective coatings in condensing economizer applications. ZN691 coating exhibited better protection than ANORZINC and TROPIS versus time in contact with 40% of H2SO4, HNO3 and 37% HCl. Electrochemical results confirmed the superior performance of ZN691 over ANORZINC and TROPIS with corrosion rates at 0.017, 0.098 and 0.097 mpy respectively. Condensation experiments for ZN691 showed a water collection rate of 1.487 ml m−2 h−1 at 40 °C and 100% RH. According to the results, the Zn rich epoxy-based coatings are promising for corrosion protection of condensing economizer elements.

The objective of this research was to investigate the current status of water-collection behaviours and their determinants, which are associated with the burden of collecting water. This research was focused on the remote hinterlands of Nepal, and little is known about the residents' livelihoods; therefore, particular attention was paid to the household burdens in terms of the time devoted to water-collection activities. A survey was conducted in households from mountainous regions of Nepal whose infrastructure is limited in terms of poor water supply and access to electricity. The results of the survey indicated that one or two members of a household were responsible for collecting water, and approximately 40% of households used multiple sites. Moreover, household members visited their collection location approximately 3–4 times per day. Based on the water-collection behaviours of each household member, an average of 148.6 min were used for water-collection activities each day. The factors associated with the total time devoted to water-collection activities include the number of household members, the sex of the household head, the number of years of education of the household members, and the share of children and women engaged in water collection. The estimation results also indicated that members of households with access to water storage spent less time collecting water. The results yield key information from villagers in remote mountainous regions, and substantial improvement is pivotal for achieving universal water access under sustainable development goals. [ABSTRACT FROM AUTHOR]

Development of porous materials with anti-fouling and remote controllability is highly desired for oil-water separation application yet still challenging. Herein, to address this challenge, a sponge with unusual superhydrophilicity/superoleophobicity and magnetic property was fabricated through a dip-coating process. To exploit its superhydrophilic/superoleophobic property, the obtained sponge was used as a reusable water sorbent scaffold to collect water from bulk oils without absorbing any oil. Owing to its magnetic property, the sponge was manipulated remotely by a magnet without touching it directly during the whole water collection process, which could potentially lower the cost of the water collection process. Apart from acting as a water-absorbing material, the sponge can also be used as affiliation material to separate water from oil-water mixture and oil in water emulsion selectively, when fixed into a cone funnel. This research provides a key addition to the field of oil-water separation materials. [ABSTRACT FROM AUTHOR]

Water collection from fog has received much attention to meet the challenges of scarcity of clean drinking water in desert and arid regions. Currently, solar‐thermal technology is being used as an efficient, sustainable, and low‐cost method for water desalination to produce clean water. To collect the clean water, in recent years, most researchers have designed the structure of water collection surfaces. However, the heat released during the liquefaction process of droplets has an adverse effect on the condensation of droplets, and thus affecting the water collection efficiency. Here, in order to improve water collection efficiency, a radiative cooling layer is introduced on the back of the collection surface to dissipate the heat released during droplet liquefaction. The radiative cooling layer, consisting of poly(vinylidene fluoride‐co‐hexafluoropropene) embedded with SiO2 and CaMoO4 nanoparticles, can theoretically cool 18.1 °C below the ambient temperature in the daytime. With the addition of cooling coating on the back of the water collection surface, the water harvesting efficiency can be increased by 43–52%. The developed water harvesting device may provide a new pathway to the efficient collection of fresh water. [ABSTRACT FROM AUTHOR]

To address water shortages worldwide, proactive measures are needed to supplement the water supply. In arid regions, many plants and animals use fog or the moisture in air as a source of water. An important consideration for efficient water collection is to transport collected water droplets as rapidly as possible to storage/use before they are evaporated. Triangular geometry has been used for faster transport of water droplets. In the case of a triangular geometry, if a droplet is placed at its apex, the droplet is driven across the triangular region by the Laplace pressure gradient. However, the magnitude of the gradient decreases along the triangle. In this study, nested triangles were designed to provide a higher pressure gradient. Water condensation and transport studies were carried out on the nested pattern at a temperature below the dew point in ambient air. It was found that the nested pattern increases the droplet travel speed. [ABSTRACT FROM AUTHOR]

In arid deserts, water supply is supplemented by water from fog and condensation. Once the droplets are collected, they are transported to a location where they are consumed or stored before they evaporate. Conical geometries or triangular patterns are known to create Laplace pressure gradient inside droplets which facilitates droplet transport. Water collection by fog on conical and triangular patterns have been studied. The research on the water collection by condensation exist only on flat triangular patterns. These flat surfaces have limitations for practical purposes, such as the Laplace pressure gradient does not act of droplets unless they touch the border. That is not the case in cones, which makes them superior for practical water collection. In this study, for the first time, water collection from condensation on cones have been studied. Cones of different tip angle, cone length, and surface area were used. Effect of inclination angle and array was also characterized. The results are compared to water collection by fog. [ABSTRACT FROM AUTHOR]

Copyright of Boletín Geológico y Minero is the property of Instituto Tecnologico Geominero De Espana and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)