The sensitivity of fluvial sediment load to climate change and predictions of future sediment load in cold basins remain poorly investigated, although changes in river sediment transport have ...important geomorphological, ecological, and societal implications. Here, we adapt a sediment elasticity approach to examine the sensitivity of fluvial suspended sediment load to changes in air temperature and precipitation in the headwater of the Yangtze River (HYR) on the inner Tibetan Plateau. Results show that every 1 °C increase in air temperature can increase the suspended sediment load by 14–27 % by intensifying thermally-driven glacial and permafrost erosional processes, and every 10 % increase in precipitation can increase the suspended sediment load by 16–24 % through enhancing pluvial-driven erosional processes. We predict an increase of 60–85 % in the suspended sediment loads in HYR by 2050 relative to the present-day period under the Representative Concentration Pathway 4.5, as both air temperature and precipitation are projected to increase. Our analysis highlights that smaller upland rivers appear to respond to modern climate change more rapidly and intensively than larger downstream rivers due to the larger glacier and permafrost coverages, poorer vegetation, as well as steeper fluvial relief, and higher sediment connectivity. This study provides a framework and a data-driven sediment elasticity approach to predict climate change and cryosphere degradation-driven changes in future fluvial suspended sediment load in cold basins, highlights the importance of the spatial scale effects in modulating fluvial responses, and has implications for assessing the impacts of climate change on channel morphology and aquatic ecosystems.
•A sediment elasticity approach is introduced to estimate sediment load sensitivity to climate change in cold basins•One degree increase in temperature can increase sediment load by 14-27%, and every 10% increase in precipitation can lead to a 16-24% increase in sediment load in HYR•Sediment loads will increase in a warmer and wetter climate, with negative impacts on hydropower and aquatic ecosystems•Sediment loads tend to respond more rapidly and intensively to climate change in upland smaller basins than larger downstream basins
Abstract
Hematite has a great potential as a photoanode for photoelectrochemical (PEC) water splitting by converting solar energy into hydrogen fuels, but the solar-to-hydrogen conversion efficiency ...of state-of-the-art hematite photoelectrodes are still far below the values required for practical hydrogen production. Here, we report a core-shell formation of gradient tantalum-doped hematite homojunction nanorods by combination of hydrothermal regrowth strategy and hybrid microwave annealing, which enhances the photocurrent density and reduces the turn-on voltage simultaneously. The unusual bi-functional effects originate from the passivation of the surface states and intrinsic built-in electric field by the homojunction formation. The additional driving force provided by the field can effectively suppress charge–carrier recombination both in the bulk and on the surface of hematite, especially at lower potentials. Moreover, the synthesized homojunction shows a remarkable synergy with NiFe(OH)
x
cocatalyst with significant additional improvements of photocurrent density and cathodic shift of turn-on voltage. The work has nicely demonstrated multiple collaborative strategies of gradient doping, homojunction formation, and cocatalyst modification, and the concept could shed light on designing and constructing the efficient nanostructures of semiconductor photoelectrodes in the field of solar energy conversion.
Rivers originating in High Mountain Asia are crucial lifelines for one-third of the world’s population. These fragile headwaters are now experiencing amplified climate change, glacier melt, and ...permafrost thaw. Observational data from 28 headwater basins demonstrate substantial increases in both annual runoff and annual sediment fluxes across the past six decades. The increases are accelerating from the mid-1990s in response to a warmer and wetter climate. The total sediment flux from High Mountain Asia is projected to more than double by 2050 under an extreme climate change scenario. These findings have far-reaching implications for the region’s hydropower, food, and environmental security.
For realizing scalable solar hydrogen synthesis, the development of visible-light-absorbing photocatalysts capable of overall water splitting is essential. Metal sulfides can capture visible light ...efficiently; however, their utilization in water splitting has long been plagued by the poor resilience against hole oxidation. Herein, we report that the ZnIn2S4 monolayers with dual defects (Ag dopants and nanoholes) accessed via cation exchange display stoichiometric H2 and O2 evolution in pure water under visible light irradiation. In-depth characterization and modeling disclose that the dual-defect structure endows the ZnIn2S4 monolayers with optimized light absorption and carrier dynamics. More significantly, the dual defects cooperatively function as active sites for water oxidation (Ag dopants) and reduction (nanoholes), thus leading to steady performance in photocatalytic overall water splitting without the assistance of cocatalysts. This work demonstrates a feasible way for fulfilling “all-in-one” photocatalyst design and manifests its great potential in addressing the stability issues associated with sulfide-based photocatalysts.
This study was conducted to evaluate the effect of curcumin on laying performance, egg quality, biochemical indicators, hormone levels, and immune activity in hens under heat stress. Hy-Line brown ...hens (280-day-old) were fed with 0, 100, 150, and 200 mg/kg of curcumin during a 42-D experiment. Compared with the control treatment, supplementation with 150 mg/kg of curcumin improved laying performance and egg quality by significantly increasing egg production, eggshell thickness, eggshell strength (P < 0.01), and albumen height (P < 0.05) while decreasing the feed-to-egg ratio. Antioxidant activity was improved by significantly increasing the activity of superoxide dismutase and glutathione peroxidase but decreasing malondialdehyde levels in serum (P < 0.05) and significantly increasing the levels of follicle-stimulating hormone, luteinizing hormone, estradiol, IgG, IgA, and complement C3 activity in serum (P < 0.05). These results indicated that supplemental 150 mg/kg curcumin can improve productive performance, antioxidant enzyme activity, and immune function in laying hens under the heat stress conditions applied in the present study.
•We study effect of quench rate on corrosion behaviour in various over-aged alloys.•Corrosion resistance keeps increase with ageing time if slowly quenched.•Severe overageing will slightly reduce ...corrosion resistance if fast quenched.•Quenching has a much higher effect on intergranular corrosion than overageing step.•Copper content in precipitates is the most important factor for corrosion property.
The corrosion behaviour of AA7050 on different quench rates and ageing conditions has been studied using immersion tests and complementary techniques like SEM, TEM-EDS and Scanning Kelvin probe force microscopy. The results reveal that overageing temper can effectively reduce corrosion sensitivity caused by peak-ageing treatment. The comparison of corrosion resistance in the over-aged and severely over-aged alloys shows significant dependence of the changes in corrosion resistance with ageing time on quench rate. The results are discussed in terms of the changes in the composition and distribution of precipitates, width of precipitate-free zone and diffusivity of alloying elements.
To construct novel ion receptors and D-A self-assembly systems for materials with better functions, the annulation of a tetrathiafulvalene donor with a magnesium norphthalocyanine core via a flexible ...tetrathiacrown ether bridge afforded a new triad
. The structure of this product was characterized by 1H NMR and infrared spectroscopy, time-of-flight mass spectrometry, and elemental analysis. The optical and electrochemical properties were investigated using UV-vis spectroscopy and cyclic voltammetry. The complex of triad
and 2,3,5,6- tetrafluoro-7,7,8,8-tetracyanoquinodimethane produced electron transfer with a radical cationic character, as confirmed by UV-Vis and electron paramagnetic resonance analysis. Furthermore, the target compound presented evident intramolecular charge-transfer interactions in ground states, which were explained using density functional theory. Furthermore, norphthalocyanine
was able to coordinate Ag
through the peripheral ligating oxathiaether crown.
Abstract
Ferroelectrics are considered excellent photocatalytic candidates for solar fuel production because of the unidirectional charge separation and above-gap photovoltage. Nevertheless, the ...performance of ferroelectric photocatalysts is often moderate. A few studies showed that these types of photocatalysts could achieve overall water splitting. This paper proposes an approach to fabricating interfacial charge-collecting nanostructures on positive and negative domains of ferroelectric, enabling water splitting in ferroelectric photocatalysts. The present study observes efficient accumulations of photogenerated electrons and holes within their thermalization length (~50 nm) around Au nanoparticles located in the positive and negative domains of a BaTiO
3
single crystal. Photocatalytic overall water splitting is observed on a ferroelectric BaTiO
3
single crystal after assembling oxidation and reduction cocatalysts on the positively and negatively charged Au nanoparticles, respectively. The fabrication of bipolar charge-collecting structures on ferroelectrics to achieve overall water splitting offers a way to utilize the energetic photogenerated charges in solar energy conversion.
Vehicular sensor networks have been widely applied in intelligent traffic systems in recent years. Because of the specificity of vehicular sensor networks, they require an enhanced, secure and ...efficient authentication scheme. Existing authentication protocols are vulnerable to some problems, such as a high computational overhead with certificate distribution and revocation, strong reliance on tamper-proof devices, limited scalability when building many secure channels, and an inability to detect hardware tampering attacks. In this paper, an improved authentication scheme using certificateless public key cryptography is proposed to address these problems. A security analysis of our scheme shows that our protocol provides an enhanced secure anonymous authentication, which is resilient against major security threats. Furthermore, the proposed scheme reduces the incidence of node compromise and replication attacks. The scheme also provides a malicious-node detection and warning mechanism, which can quickly identify compromised static nodes and immediately alert the administrative department. With performance evaluations, the scheme can obtain better trade-offs between security and efficiency than the well-known available schemes.
The global coronavirus disease 2019 (COVID-19) pandemic has led to a health crisis. It remains unclear how anxiety affects blood pressure (BP) and cardiovascular risk among older patients with ...hypertension. In this study, we extracted longitudinal data on home BP monitored via a smartphone-based application in 3724 elderly patients with hypertension from a clinical trial (60-80 years; 240 in Wuhan and 3484 in non-Wuhan areas) to examine changes in morning BP during the COVID-19 outbreak in China. Anxiety was evaluated using Generalized Anxiety Disorder-7 item scores. Changes in morning systolic BP (SBP) were analyzed for five 30-day periods during the pandemic (October 21, 2019 to March 21, 2020), including the pre-epidemic, incubation, developing, outbreak, and plateau periods. Data on cardiovascular events were prospectively collected for one year. A total of 262 individuals (7.0%) reported an increased level of anxiety, and 3462 individuals (93.0%) did not. Patients with anxiety showed higher morning SBP than patients without anxiety, and the between-group differences in SBP change were +1.2 mmHg and +1.7 mmHg during the outbreak and plateau periods (P < 0.05), respectively. The seasonal BP variation in winter among patients with anxiety was suppressed during the pandemic. Anxious patients had higher rates of uncontrolled BP. During the 1-year follow-up period, patients with anxiety had an increased risk of cardiovascular events with a hazard ratio of 2.47 (95% confidence interval, 1.10-5.58; P = 0.03). In summary, COVID-19-related anxiety was associated with a short-term increase in morning SBP among older patients and led to a greater risk of cardiovascular events. (ClinicalTrials. gov number, NCT03015311).
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