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The role of reservoir size in driving methane emissions in China
Get PDFReservoirs play a crucial role as sources of methane (CH₄) emissions, with emission rates and quantities varying widely depending on reservoir size due to factors such as surface area, water depth, usage, operational methods, and spatial distribution. Gaining insights into emission characteristics across different reservoir sizes can aid in designing and managing reservoirs to mitigate CH₄ emissions effectively. In this study, machine learning models were applied to estimate both diffusive and ebullitive CH₄ emissions across 97,435 reservoirs in China, spanning five categories of storage capacity. This comprehensive assessment covers nearly all reservoirs within the country, revealing total CH₄ emissions of approximately 5,414 Gg. Reservoirs > 0.01 km3 are responsible for about 90 % of these emissions, primarily due to high diffusive flux rates and extensive surface areas. Elevated CH₄ diffusion in reservoirs > 0.01 km3 is largely influenced by their thermal stratification and capacity for organic matter accumulation. Furthermore, these reservoirs are particularly vulnerable to climate warming, which could accelerate CH₄ emission rates more rapidly in larger reservoirs than in smaller ones (below 0.01 km³). Consequently, prioritising CH₄ management in reservoirs > 0.01 km3 is imperative. Nevertheless, the high ebullitive flux of CH₄ in reservoirs < 0.01 km3, linked to their shallow depth, highlighting the potential for significant CH₄ ebullition from smaller aquatic systems. Given large and small-ranged reservoirs' distinct spatial distribution patterns, targeted management strategies are recommended: project-level management for large reservoirs and basin-level approaches for smaller reservoirs
Roles of hormones in regulating root growth–water interactions
Get PDFWater stress presents a critical challenge affecting plant growth and agricultural productivity, with drought alone causing substantial yield losses. Roots serve as the primary site for water uptake, enabling plants to detect water stress by sensing changes in soil moisture levels. This initial perception prompts roots to initiate a spectrum of adaptive responses at morphological, anatomical, and biochemical levels. In addition to coping with severe water stress conditions such as drought, roots also respond to microscale variations in water availability within the rhizosphere as they navigate through soil, exhibiting responses such as hydrotropism, xerobranching, and hydropatterning. These adaptive responses are orchestrated by dynamic and sophisticated sensing and signalling mechanisms mediated by plant hormones at the cellular level. This review explores recent advances in our understanding of root responses to water stress, emphasizing the hormonal mechanisms underpinning these adaptations. Furthermore, it outlines future perspectives aimed at enhancing crop resilience to water stress through improved understanding and manipulation of root–water interactions
Use of a violence risk prediction tool (Oxford Mental Illness and Violence) in early intervention in psychosis services: mixed methods study of acceptability, feasibility and clinical role
Get PDFBackground Scalable assessment tools for precision psychiatry are of increasing clinical interest. One clinical risk assessment that might be improved by such approaches is assessment of violence perpetration risk. This is an important adverse outcome to reduce for some people presenting to services for first-episode psychosis. A prediction tool (Oxford Mental Illness and Violence (OxMIV)) has been externally validated in these services, but clinical acceptability and role need to be examined and developed. Aims This study aimed to understand clinical use of the OxMIV tool to support violence risk management in early intervention in psychosis services in terms of acceptability to clinicians, patients and carers, practical feasibility, perceived utility, impact and role. Method A mixed methods approach integrated quantitative data on utility and patterns of use of the OxMIV tool over 12 months in two services with qualitative data from interviews of 20 clinicians and 12 patients and carers. Results The OxMIV tool was used 141 times, mostly in new assessments. Required information was available, with only family history items scored unknown to any notable degree. The OxMIV tool was deemed helpful by clinicians in most cases, especially if there were previous risk concerns. It was acceptable practically, and broadly for the service, for which its concordance with clinical judgement was important. Patients and carers thought it could improve openness. There was some limited impact on plans for clinical support. Conclusions The OxMIV tool met an identified clinical need to support clinical assessment for violence risk. Linkage to intervention pathways is a research priority
Concatenated Thresholds: Rehabilitation of an 18th Century House for a Family of Musicians in Seville, Spain
Get PDFAccomplished in 2018, the refurbishment of an 18th-century house, which is located in the historic centre of Seville (Spain), constitutes a statement of heritage reactivation as a solid platform for keeping historic centres alive. Rehabilitated by Baum Lab under clear heritage intervention principles—analysis, diagnosis, depuration, consolidation and prothesis—this project aimed to preserve not only spatial and construction values but also their role in shaping contemporary urban life and social dynamics.The new additions, although built of contemporary materials, aim to create a symbiotic coexistence of old and new materials, avoiding a stark contrast. The existing values of the building were preserved not only by revealing and highlighting the original materials and exposing vernacular construction techniques but also by bringing back the hybrid spatial conditions typically provided by this typology to contemporary, domestic dynamics. The sequence of spaces traditionally encountered in Mediterranean patio houses facilitated the establishment of a promenade through buildings, with the patio serving as the central, social core area of these houses.The conceptual strategy for heritage in this rehabilitation was adopted from the design phase until the end of the construction phase. Traditional techniques were employed to consolidate arches, walls, vaults, and lintels—by recovering bricks, using lime mortars, or restoring timber pieces—while the new prostheses, fabricated with contemporary technology, were designed with easy-to-disassemble details. This approach, therefore, aimed to create a new chapter in the life of the building by adding a fresh, permeable, contemporary layer that enriches the historic narrative up to the present without overwriting previous strata.By embracing this nuanced methodology, the project addressed the potential of heritage interventions to contribute not only to preservation but also to the ongoing evolution of historic architecture in contemporary contexts
Influence of Magnetic Anisotropy on the Ground State of [CH3NH3]Fe(HCOO)3: Insights into the Improper Modulated Magnetic Structure
Get PDFT h e h y b r i d p e r o v s k i t e s [ C H 3 N H 3 ] -CoxNix−1(HCOO)3 with x = 0, 0.25, 0.5, 0.75, and 1.0 possess multiple phase transitions, including incommensurate structures. Notably, [CH3NH3]Ni(HCOO)3 features a proper magnetically incommensurate structure ground state. To explore similar behavior, we investigated the isomorphous [CH3NH3]Fe-(HCOO)3 (1). A combination of magnetometry measurements, single crystal and powder neutron diffraction, and density functional theory calculations have been used to accurately determine and understand the sequence of nuclear and magnetic phases present in compound 1. At room temperature, it crystallizes in the Pnma space group with a perovskite structure. Below 170 K,new satellite reflections indicate a transition to a modulated structure, refined in the Pnma(00γ)0s0 with q1 = 0.1662(2)c*. At 75 K, the satellite reflections become closer to the main reflections, indicating a second transition, which maintains the superspace group symmetry but decreases the modulation wave vector to q2 =0.1425(2)c*, i.e., with a longer modulation period. This modulation persists to 2 K, overlapping with the onset of 3D antiferromagnetic order at 17 K, offering a unique opportunity to study magneto-structural coupling. Our results point to animproper magnetic modulated structure where, interestingly, the spins are perpendicular to those of previously reported compounds
Design of a Combined Heat Store and Heat Exchanger for CAES Systems
Get PDFA combined heat store and heat exchanger unit (HSX) intended for compressed air energy storage (CAES) is presented. The unit is directly charged by the pressurised air emerging from the compression train, which removes the need for a secondary low-pressure air circuit. Salt is used as the thermal storage medium due to its good heat capacity, thermal conductivity, and its ability to accommodate the thermal expansion of the stainless-steel pipes. This paper uses a CAES system (15 MW, 12-h discharge) driven by an offshore wind turbine as a case study. There are not many commercial CAES systems in operation; however, the levelized cost of the heat storage subsystem of a CAES system (i.e. heat store, set of heat exchangers and ancillary low-pressure circuit) ranges between 45 and 48 £/MWh. Findings show that the most cost-effective design for a HSX has a capital cost of ∼£55k. This translates into a levelized cost of storage of ∼31.5 £/MWh. The roundtrip exergy efficiency of this design is 93.7 %. This accounts for heat-exergy and pressure-exergy losses; losses to ambient are not considered. A HSX unit can considerably reduce the overall cost of a CAES system
Photoelectron circular dichroism of aqueous-phase alanine
Get PDFAmino acids and other small chiral molecules play key roles in biochemistry. However, in order to understand how these molecules behave in vivo, it is necessary to study them under aqueous-phase conditions. Photoelectron circular dichroism (PECD) has emerged as an extremely sensitive probe of chiral molecules, but its suitability for application to aqueous solutions had not yet been proven. Here, we report on our PECD measurements of aqueous-phase alanine, the simplest chiral amino acid. We demonstrate that the PECD response of alanine in water is different for each of alanine's carbon atoms, and is sensitive to molecular structure changes (protonation states) related to the solution pH. For C 1s photoionization of alanine's carboxylic acid group, we report PECD of comparable magnitude to that observed in valence-band photoelectron spectroscopy of gas-phase alanine. We identify key differences between PECD experiments from liquids and gases, discuss how PECD may provide information regarding solution-specific phenomena — for example the nature and chirality of the solvation shell surrounding chiral molecules in water — and highlight liquid-phase PECD as a powerful new tool for the study of aqueous-phase chiral molecules of biological relevance
Pattern formation on an ice surface
No full textA linear stability model based on a phase-field method is established to study the formation of ripples on the ice surface. The pattern on horizontal ice surfaces, e.g. glaciers and frozen lakes, is found to be originating from a gravity-driven instability by studying ice–water–air flows with a range of water and ice thicknesses. Contrary to gravity, surface tension and viscosity act to suppress the instability. The results demonstrate that a larger value of either water thickness or ice thickness corresponds to a longer dominant wavelength of the pattern, and a favourable wavelength of 90 mm is predicted, in agreement with observations from nature. Furthermore, the profiles of the most unstable perturbations are found to be with two peaks at the ice–water and water–air interfaces whose ratio decreases exponentially with the water thickness and wavenumber
Gigawatt-hour to terawatt-hour salt cavern supercapacitors and supercapatteries
Get PDFThe advancement of energy technology has led to a notable increase in the contribution from renewable energy sources to the global energy supply and consumption landscape. Nevertheless, although inexhaustible and clean, the intermittency and instability of these energy sources present significant challenges to their wider deployment, necessitating the development of robust energy storage systems. Also, it is historical that the demand for power supply also varies significantly between day and night, and between different time zones, requesting large scale storage capacity for not only load levelling but also power supply security. In this article, salt caverns, which offer a sealable and unmatched large space and are currently employed for storage of compressed energy gases, are proposed for construction of giga- to tera-watt-hour scale supercapacitors and supercapatteries as an effective storage solution to renewable energy farms and national and international power grids. Following an introduction to salt caverns and their uses for storage of compressed air, natural gas, hydrogen and carbon dioxide, the potential is explored for construction of supercapacitors and supercapatteries in salt caverns. The discussion is specially focused on aqueous electrolytes that can be formed by utilising the salty water or brine from the construction of the salt cavern, and the respective electrode materials suitable for such aqueous electrolytes. Furthermore, calculations and analyses are given on the prospects of construction and application of giga- to tera-watt-hour supercapacitors and supercapatteries in salt caverns. Last, but not least, foreseeable challenges of such unprecedented ultra-large scale electrochemical energy storage devices are discussed with possible solutions
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