Ambient‐pressure‐dried (APD) preparation of transition metal carbide/nitrides (MXene) aerogels is highly desirable yet remains highly challenging. Here, ultrathin, high‐strength‐to‐weight‐ratio, ...renewable cellulose nanofibers (CNFs) are efficiently utilized to assist in the APD preparation of ultralight yet robust, highly conductive, large‐area MXene‐based aerogels via a facile, energy‐efficient, eco‐friendly, and scalable freezing‐exchanging‐drying approach. The strong interactions of large‐aspect‐ratio CNF and MXene as well as the biomimetic nacre‐like microstructure induce high mechanical strength and stability to avoid the structure collapse of aerogels in the APD process. Abundant functional groups of CNFs facilitate the chemical crosslinking of MXene‐based aerogels, significantly improving the hydrophobicity, water resistance, and even oxidation stability. The ultrathin, 1D nature of the CNF renders the minimal MXenes’ interlayered gaps and numerous heterogeneous interfaces, yielding the excellent conductivity and electromagnetic interference (EMI) shielding performance of aerogels. The synergies of the MXene, CNF, and abundant pores efficiently improve the EMI shielding performance, photothermal conversion, and absorption of viscous crude oil. This work shows great promises of the APD, multifunctional MXene‐based aerogels in electromagnetic protection or compatibility, thermal therapy, and oil‐water separation applications.
Employing the renewable, ultrathin, large‐aspect‐ratio cellulose nanofiber (CNF) as a cross‐linker, the large‐area, ultralight yet robust MXene‐based aerogels with multifunctionality are prepared through the simple, energy‐efficient, and scalable ambient‐pressure‐dried approach. The synergies of the MXene, CNF, and abundant pores efficiently improve the EMI shielding performance, dye adsorption, photothermal conversion, and absorption of viscous crude oil.
Laminated multifunctional composites are highly desired in modern lightweight engineering structures. The purpose of this study is to develop a composite laminate with impact tolerance, delamination ...healing, strain sensing, Joule heating, deicing, and room temperature shape restoration functionalities. In this study, a novel self-healable and recyclable shape memory vitrimer was used as the matrix, unidirectional glass fabric was used as reinforcement, and tension programmed shape memory alloy (SMA) wires were used as z-pins. To provide multifunctionality, the programmed SMA wires were further twisted and formed into sinusoidal shape. Copper wire strands were hooked to the sinusoidal SMA z-pins to make them a closed circuit. Low velocity impact, compression after impact, damage self-healing, deicing, and room temperature shape restoration tests were conducted. The tests result show that the desired multifunctionality of the laminated composite was achieved. The hybrid laminate provides a promising design for lightweight load-carrying engineering structures.
•Most urban soil research is on supporting and regulating ecosystem services.•Soil biological activity, nutrient cycling and carbon storage are commonly quantified.•Food provision, cultural and ...water-related services are underexplored.•Urban soil multifunctionality is recommended as a direction for future research.•Work is needed on global studies, community integration and potential future drivers.
The expansion of urban areas worldwide is increasing the anthropogenic impact upon soil and highlights the important role of urban areas in supporting a sustainable future. As such, urban soils are becoming more important in the delivery of a broad range of ecosystem services (ESs), including carbon storage and climate regulation, biomass provision for food and water flow regulation, and recreational benefits. In this review, we aim to support the development of this emerging research area and, subsequently, support the improved treatment and management of urban soil and ES delivery. We present a systematic review of which ESs have been studied and examine trends in research using a co-occurrence analysis of key terms. We then provide a summary review of current knowledge on ESs and identify the gaps in knowledge. Our review highlights that this is a young, but growing, field of research, with a marked increase in publications since 2014. We found that supporting processes and regulating services were most commonly studied, with 88% and 71% of the papers relating to quantitative studies addressing these, respectively. Cultural, provisioning and water-related ESs were relatively understudied, suggesting key gaps for future research. However, this may be attributable to a disconnection between academic communities rather than a lack of knowledge. Fewer than 20% of quantitative studies addressed more than two ESs simultaneously, leading us to suggest that urban soil multifunctionality is a key area for future research, and highlighting the need to integrate understanding of urban soil ESs across disciplines and professions. In addition to this overarching suggestion, we propose six research gaps and opportunities: further research into biomass provision for food, water-related ESs and cultural ESs; greater geographical representation; further interconnection between research and practitioner communities; and a focus on the future drivers of soil change in urban environments.
Summary
Extensive research shows that more species‐rich assemblages are generally more productive and efficient in resource use than comparable assemblages with fewer species. But the question of how ...diversity simultaneously affects the wide variety of ecological functions that ecosystems perform remains relatively understudied. It presents several analytical and empirical challenges that remain unresolved. In particular, researchers have developed several disparate metrics to quantify multifunctionality, each characterizing different aspects of the concept and each with pros and cons.
We compare four approaches to characterizing multifunctionality and its dependence on biodiversity, quantifying (i) magnitudes of multiple individual functions separately, (ii) the extent to which different species promote different functions, (iii) the average level of a suite of functions and (iv) the number of functions that simultaneously exceeds a critical threshold.
We illustrate each approach using data from the pan‐European BIODEPTH experiment and the R multifunc package developed for this purpose, evaluate the strengths and weaknesses of each approach and implement several methodological improvements.
We conclude that an extension of the fourth approach that systematically explores all possible threshold values provides the most comprehensive description of multifunctionality to date. We outline this method and recommend its use in future research.
Many studies have investigated the effects of environmental context on biodiversity or multifunctionality in alpine regions, but it is uncertain how human pressure and climate may affect their ...relationships. Here, we combined the comparative map profile method with multivariate datasets to assess the spatial pattern of ecosystem multifunctionality and further identify the effects of human pressure and climate on the spatial distribution of biodiversity-multifunctionality relationships in alpine ecosystems of the Qinghai-Tibetan Plateau (QTP). Our results indicate that at least 93% of the areas in the study region show a positive correlation between biodiversity and ecosystem multifunctionality across the QTP. Biodiversity-multifunctionality relationships with increasing human pressure show a decreasing trend in the forest, alpine meadow, and alpine steppe ecosystems, while an opposite pattern was found in the alpine desert steppe ecosystem. More importantly, aridity significantly strengthened the synergistic relationship between biodiversity and ecosystem multifunctionality in forest and alpine meadow ecosystems. Taken together, our results provide insights into the importance of protecting and maintaining biodiversity and ecosystem multifunctionality in response to climate change and human pressure in the alpine region.
Trade-offs between soil functions hamper maximizing soil multifunctionality in agroecosystems.Taking soil microbial functional trade-offs into consideration in agricultural management is crucial for ...optimizing the impacts of changes in soil microbial communities on soil health in agroecosystems.Interactions within soil microbial communities influence functional trade-offs.Manipulating soil microbial diversity and interactions through soil health-improving management can alleviate functional trade-offs and improve soil health and agricultural sustainability.Better mechanistic understanding of the interdependencies between soil-induced functions is essential to improve soil health and agricultural sustainability.
Soil microbial communities play pivotal roles in maintaining soil health in agroecosystems. However, how the delivery of multiple microbial functions in agroecosystems is maintained remains poorly understood. This may put us at risk of incurring unexpected trade-offs between soil functions. We elucidate how interactions between soil microbes can lead to trade-offs in the functioning of agricultural soils. Interactions within soil microbial communities can result in not only positive but also neutral and negative relationships among soil functions. Altering soil conditions through soil health-improving agricultural management can alleviate these functional trade-offs by promoting the diversity and interrelationships of soil microbes, which can help to achieve more productive and sustainable agroecosystems.
Soil microbial communities play pivotal roles in maintaining soil health in agroecosystems. However, how the delivery of multiple microbial functions in agroecosystems is maintained remains poorly understood. This may put us at risk of incurring unexpected trade-offs between soil functions. We elucidate how interactions between soil microbes can lead to trade-offs in the functioning of agricultural soils. Interactions within soil microbial communities can result in not only positive but also neutral and negative relationships among soil functions. Altering soil conditions through soil health-improving agricultural management can alleviate these functional trade-offs by promoting the diversity and interrelationships of soil microbes, which can help to achieve more productive and sustainable agroecosystems.
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•Lanthanide upconversion nanoparticles show fascinating properties for the development of wide research areas.•Key strategies for synthesis and characterization of upconversion ...core/shell nanopartilces.•Exploiting the effect of constructing upconversion core/shell structure.•Future outlook of challenges and opportunities for core/shell upconversion nanoparticles are discussed.
Lanthanide-doped upconversion nanoparticles (UCNPs) are guest-host systems with lanthanide ions as guest dispersed in a dielectric material as the inorganic host. Over the past decades, much efforts have been devoted to UCNPs in a number of biological applications due to their low toxicity, high chemical stability and high signal-to-noise ratio. Lanthanide ions distributed in conventional UCNPs with only core structures easily lose their excitation and emission energy through energy migration to the surface quenchers, weakening the emission intensities. A hierarchically designed core/shell structure may address the challenges above by blocking the emitters from the surface and surrounding quenchers. Besides, it offers not only a flexible construction by employing active shells to endow the UCNPs with new features from enhanced light harvesting and multicolor tunability to therapeutic functions, but also largely preserves the optical integrity of UCNPs. In this review, we primarily focus on recent progress in the hierarchically designed core/shell UCNPs and discussing their challenges and opportunities. We summarize several strategies to synthesize and characterize the core/shell structure and particularly highlight the unprecedented properties through regulating the core/shell structure, including light harvesting, tuning of excitation wavelength, enhancement of emission efficiency, emission color tunability, lifetime tunability and multifunctionality. Finally, we frame the future outlook of challenges and opportunities for core/shell UCNPs.
Smart and novel materials require the replacement of conventional composites with superior ones, which requires an advanced class of composites with multi-functionality. Multi-scale composites are ...advanced composites that are reinforced with nanoscale materials along with macroscale fibers, and these materials have attracted the attention of researchers as well as various industries. Multi-scale composites have potential applications in almost every field due to their remarkable features like extraordinary mechanical, electrical, and optical properties; extremely high aspect ratios of the nanomaterial constituents; and the uniformity, flexibility, and stability of the fibers. To optimize the performance of these kinds of composites, it is crucial to understand the selection of appropriate reinforcements, processing, and utilization of these advanced materials. Most reviews in this area concentrate only on CNTs, while this review considers other nanomaterials too. Additionally, various methods to improve the dispersion of nanomaterials into the matrix are also discussed. Overall, this article focuses on the components of multi-scale composites, key challenges related to their processing, and the multi-functionality of designed multi-scale composites.
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•Multifunctionality is a crucial strategy for green spaces in compact cities.•Strategic planning and multifunctional site design need to complement each other.•Different functions and ...their interrelations need to be assessed systematically.•Delivering multifunctionality requires inter- and transdisciplinary collaboration.
Urban green infrastructure planning aims to develop green space networks on limited space in compact cities. Multifunctionality is considered key to achieving this goal as it supports planning practice that considers the ability of green spaces to provide multiple benefits concurrently. However, multifunctionality is an elusive concept and little information is available on how it is perceived and actioned by planners. Therefore, this paper will examine the application of the multifunctionality concept in urban planning based on a semi-quantitative study, including interviews with chief planners and analyses of planning documents, in 20 European cities as well as three qualitative good practice case studies. The semi-quantitative study revealed a broad awareness of the variety of social and ecological functions provided by green spaces in planning. Yet, the analysed strategic plans contained little information on how to enhance multifunctionality. Regardless of the lack of details, cities facing growth were more likely to consider promoting multifunctionality as a planning aim. The qualitative case studies in Germany (Berlin), the United Kingdom (Edinburgh) and Denmark (Aarhus) provided a detailed insight into how multifunctionality is handled on different spatial scales and revealed great differences from academic multifunctionality approaches that were developed in the context of ecosystem service assessments. The approaches applied in practice include audits based on indicators for multiple green space functions or the purposive design and management of multifunctional parks. Based on the findings, we arrive at five recommendations for promoting multifunctional urban green infrastructure in densifying urban areas: 1) undertake systematic spatial assessments of all urban green (and blue) spaces and their social, ecological and economic functions; 2) include standards and guidelines for multifunctionality in city-wide strategic planning; 3) encourage design and management for multifunctionality at the site-level while considering that not all sites must deliver the same set of functions. Further, spatial assessment, strategic planning and site design need to 4) consider synergies, trade-offs and the capacity of urban green spaces to provide functions as part of the wider green infrastructure network; and 5) largely benefit from cooperation between different sectors and public departments. These recommendations can also be instructive for research on ecosystem service assessments in order to develop approaches that more strongly correspond to the demands of planning practice.
•Three case studies of novel urban green infrastructure implementation are presented.•Effective multifunctional approaches to green infrastructure design demonstrated.•That biodiversity should be an ...intrinsic consideration in design is illustrated.•Local context and multi-stakeholder approach to design and management are integral.
If a ‘Renaturing of Cities’ strategy is to maximise the ecosystem service provision of urban green infrastructure (UGI), then detailed consideration of a habitat services, biodiversity-led approach and multifunctionality are necessary rather than relying on the assumed benefits of UGI per se. The paper presents preliminary data from three case studies, two in England and one in Germany, that explore how multifunctionality can be achieved, the stakeholders required, the usefulness of an experimental approach for demonstrating transformation, and how this can be fed back into policy. We argue that incorporating locally contextualised biodiversity-led UGI design into the planning and policy spheres contributes to the functioning and resilience of the city and provides the adaptability to respond to locally contextualised challenges, such as overheating, flooding, air pollution, health and wellbeing as well as biodiversity loss. Framing our research to encompass both the science of biodiversity-led UGI and co-developing methods for incorporating a strategic approach to implementation of biodiversity-led UGI by planners and developers addresses a gap in current knowledge and begins to address barriers to UGI implementation. By combining scientific with policy learning and defined urban environmental targets with community needs, our research to date has begun to demonstrate how nature-based solutions to building resilience and adaptive governance can be strategically incorporated within cities through UGI.
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