Top Layer Research Articles

Fabrication of planar halfmetallic ferromagnetic Josephson junctions with long range coupling

Superconducting junctions with a ferromagnet as the weak link, where triplet correlations can transport supercurrents over a substantial distance, have been of long-standing interest. In this work, we study the triplet transport in planar La0.7Sr0.3MnO3 (LSMO) nanowire Josephson junctions with NbTi superconducting contacts. By meticulous ion etching with an artificial Pt hard mask, the NbTi/LSMO bilayer is structured to form an LSMO bridge without damaging its top layer. We observe superconducting (critical) currents of the order of 109 A/m2 in a junction with a length of 1.3 μm, and distinguishing superconducting quantum interference (SQI) patterns when sweeping a magnetic field perpendicular (B⊥) to the plane of the wire or parallel (B∥) to the plane and along the wire. The observed Gaussian-shaped SQI pattern is attributed to the diffusive transport of triplet pairs in the LSMO. Our work demonstrates that combinations of oxide magnets with conventional (s-wave) alloy superconductors can be a promising new route to realizing superconducting spintronics.

Indian Thyroid society expert consensus on salt Iodisation

ABSTRACT Iodine, an essential micronutrient, is crucial for the production of thyroid hormones - triiodothyronine(T3) and thyroxine(T4). Thyroid hormones regulate the optimum mental development, physical growth and development, regulation of body metabolism, heat generation, and maintenance of body temperaturein an individual. Geological processes like flooding, soil erosion, deforestation, and rivers changing course, deplete the surface soil of iodine, as it is present in the top layers of soil and easily soluble in water. As a result, the population residing in the area with iodinedeficient soil, becomes susceptible to a spectrum of functional and developmental abnormalities due to dietary deficiency of iodine. Universal Salt Iodization (USI) for prevention of IDDs in India is a public health success story. The adoption of the salt iodization strategy serves as a textbook example of the journey of an intervention through the iterative loop of research to policy to programme. Salt iodization has proved to be a safe, accessible, available, affordable, and cost-effective strategy to address the burden of IDDs in India. India has been at the forefront of the efforts to control IDDs globally. India is on its way to achieving the target of > 90 percent household coverage of adequately iodized salt. Revised Food Safety and Standards (Fortification of Foods) Regulations released in 2019 introduced an upper limit for iodine concentration in salt, the adequate iodine level required at the production and consumer level, including the distribution channel at 15 – 30 ppm. Universal Salt Iodisation (USI) is India's public health success story. There is a need to consolidate progress so far and focus on strategy to reach the “last mile”. Sustainable elimination of Iodine Deficiency Disorders (IDDs) with Universal Salt Iodisation (USI) being the primary strategy needs to also factor in harmonisation with salt reduction strategy for control of non-communicable diseases.

Design considerations for a long-wavelength InAsSb detector diode

Abstract InAsSb can absorb light across the entire long wavelength range (8-12 μm) and shares many of the other relevant basic materials properties of HgCdTe, the current incumbent detector technology for this band. We discuss here the device architectures in relation to the crystal growth technical aspects using molecular beam epitaxy and propose a simplified design consisting of an InAsSb absorber with a graded wider bandgap top layer of lattice matched AlInAsSb that exhibits a spontaneously formed p-n-junction. The 77 K device performance is predicted with a numerical model that indicates that quantum efficiencies of at least 75% should be achievable. 

Fluorescence‐Enabled Colored Bilayer Subambient Radiative Cooling Coatings

AbstractPassive daytime radiative cooling has emerged as a promising green technology for the thermal management of buildings, vehicles, textiles, and electronics. Typically, both high solar reflectance and high thermal emissivity are prerequisites to achieve sufficient daytime cooling. However, colored radiative cooling materials are facing the dilemma of introducing visible light absorption, leading to challenges in balancing cooling and aesthetic demands. Here, three colored bilayer radiative cooling coatings, each comprised of a white base layer and a colored top layer with fluorescence enhancement are fabricated. Three phosphors (Sr2Si5N8:Eu2+, Y3Al5O12:Ce3+, and (Ba,Sr)SiO4:Eu2+) are employed with respective photoluminescence quantum yields (PLQYs) of 81%, 95.8%, and 91.0% as the colored pigment in the top layer. To mitigate the contradiction between coloration and solar reflectance, SiO2 microspheres are introduced into the top layer and utilize their Mie‐resonance‐based multiple scattering to increase the photoluminescent (PL) properties of the phosphors, which jointly boosts the effective solar reflectance (ESR) of the top layer. As a result, the three bilayer coatings exhibit soft colors while achieving subambient cooling with temperature drops of up to 1.5 °C. This fluorescence‐enhancement strategy may pave the way for preparing highly efficient radiative cooling coatings with tunable colors.

Dolomitic lime and silicate in no‐till: Nutritional status, soil fertility, and soybean agronomic performance

AbstractLimestone is the most widely used agricultural input for soil acidity correction and calcium (Ca) and magnesium (Mg) fertilization. However, other materials have the potential to fulfill these purposes, such as steel slags, also known as silicates. Silicates have higher solubility than limestone, serving as agents for increase pH in no‐till, in addition to being a source of Ca, Mg, and silicon (Si). This study aimed to compare the effects of surface application of dolomitic lime and calcium magnesium silicate on soil chemical properties, soybean [Glycine max (L.) Merr.] nutritional status, and grain yield under no‐till. The experiment was installed in the northwest Paraná State, Brazil, on a Rhodic Eutrustox. Lime and silicate rates were applied by broadcasting before the sowing of soybean. Silicate treatment increases soil Ca2+, pH, and base saturation up to a depth of 0.10 m. By contrast, liming effects on soil chemistry were restricted to the 0.05 m top layer after 24 months of application. The acidity correction and Ca2+ supply to greater soil depths and the increased leaf Si as a beneficial element provided by silicate treatment contributed to increasing soybean yield in the 2018/2019 and 2019/2020 seasons. Lime application, regardless of the rate, did not improve soybean yield. Waste from the steel industry can be used as acidity correctives and source of Si, Ca, and Mg, improving the agronomic performance of soybean.

Preconditioning of mountain permafrost towards degradation detected by electrical resistivity

Warming permafrost has been detected worldwide and is projected to continue during the next century by many modelling studies. In mountain regions, this can lead to potentially hazardous impacts on short time-scales by an increased tendency for slope instabilities. However, time scales of permafrost thaw and the role of the ice content are less clear, especially in heterogeneous mountain terrain, where ice content can vary between zero and supersaturated conditions over small distances. Warming of permafrost near the freezing point shows therefore complex inter-annual behaviour due to latent heat effects during thawing and the influence of the snow-cover, which is governed by highly non-linear processes itself. Here, we demonstrate a preconditioning effect within near-surface layers in mountain permafrost that causes non-linear degradation and accelerates thaw. We hypothesise that a summer heat wave, as has occurred in the Central European summers 2003, 2015 and 2022, will enhance permafrost degradation if the active layer and the top of the permafrost layer are already preconditioned, i.e. have reduced latent heat content. This preconditioning can already be effectuated by a singular warm year, leading to exceptionally strong melting of the ground ice. On sloping terrain this ice-loss can be considered as irreversible, as large parts of the melted water will drain during the process, and an equivalent build-up of ice in cold years does not happen on similar time-scales as the melting. We propose a simple geophysical approach based on electrical resistivity tomography surveys that can assess the state of preconditioning in the absence of boreholes. In addition, we will show that resistivity data from a total of 124 permafrost sites in the Andes, Europe, and Antarctic adhere to a distinct power law behaviour between unfrozen and frozen states, which confirms the consistent electrical behaviour of permafrost and active layer materials over a wide range of landforms and material composition.

Quantitative analysis of asphalt concrete’s tension-compression asymmetry effects on pavement response through 3D numerical modeling with dual viscoelastic model

Asphalt concrete (AC) exhibits noticeable tension-compression (TC) asymmetry, but it is typically considered isotropic in pavement design. This study aims to quantitatively evaluate the effect of AC’s TC asymmetry on pavement response under loading through numerical modeling. To achieve this objective, a temperature-dependent dual viscoelastic constitutive model was applied to incorporate AC’s TC asymmetry into pavement modeling. Besides, three pavement structure models, including one with thick AC layers, one with thin AC layers, and one with a Portland cement concrete (PCC) base, were developed. The responses of the three pavement structures under traffic and environmental loading conditions were simulated. Modeling results showed that AC’s TC asymmetry can significantly increase the vertical strain in AC, leading to higher stress concentration and larger deformation in AC layers. Unlike the conventional understanding that tensile strain concentrates at the bottom of AC layers, high tensile strains were observed in the top AC layers, especially for the pavement with thick AC layers or a PCC base, which may lead to top-down cracking. High tensile strains were observed on the granular subbase for the pavement with thin AC layers, which may induce bottom-up cracking. Besides, AC’s TC asymmetry also significantly increases the shear strains, especially the horizontal shear strain in AC layers, which may result in debonding and shoving distresses in AC layers. It was also noticed that the pavement response highly depends on its temperature and vehicular speed. A higher temperature or lower vehicular speed leads to more significant AC’s TC asymmetry as well as its effects on asphalt pavement’s response. The outcomes of this study are expected to help enhance the design and maintenance of more durable asphalt pavement.

Control of spontaneous charging of sliding water drops by plasma-surface treatment

Slide electrification is the spontaneous separation of electric charges at the rear of water drops sliding over solid surfaces. This study delves into how surfaces treated with a low-pressure plasma impact water slide electrification. Ar, O2, and N2 plasma treatment reduced the drop charge and contact angles on glass, quartz, and SU-8 coated with 1H,1H,2H,2H-perfluoroctyltrichlorosilane (PFOTS), and polystyrene. Conversely, 64% higher drop charge was achieved using electrode-facing treatment in plasma chamber. Based on the zeta potential, Kelvin potential, and XPS measurements, the plasma effects were attributed to alterations of the topmost layer's chemistry, such as oxidation and etching, and superficially charge deposition. The surface top layer charges were less negative after electrode-facing and more negative after bulk plasma treatment. As a result, the zeta potential was less negative after electrode-facing and more negative after bulk plasma treatment. Although the fluorinated layer was applied after plasma activation, we observed a discernible impact of plasma-glass treatment on drop charging. Plasma surface modification offers a means to adjust drop charges: electrode-facing treatment of the fluorinated layer leads to an enhanced drop charge, while plasma treatment on the substrate prior to fluorination diminishes drop charges, all without affecting contact angles or surface roughness.

Shaking table tests on seismic performance of a five-story reinforced concrete frame structure with MoS2 sliding bearings and steel dampers

The seismic performance of friction isolated structure is greatly affected by the friction coefficient, and the combination of low friction material and limit device is an available option. Via the Motion State module simulating the friction conditions and the Bouc Wen model describing the restoring characteristic of the steel dampers, a single-degree-of-freedom model was established to investigate the influence of the friction coefficient and limit stiffness on the isolation effect. Then, for the evaluation of the seismic performance of the proposed isolation system with molybdenum disulfide (MoS2) sliding bearings and steel dampers, the shaking table tests of a 1/5 scaled five-story reinforced concrete frame structure model, subjected to three ground motions with different peak ground acceleration, were implemented to obtain the isolation layer drift, absolute acceleration, inter-story shear and damage energy of the structure under the testing conditions of free sliding, limited sliding, multi-dimensional seismic excitation, and top additional layer sliding. It is found that the ideal friction coefficient for sliding isolated structure is 0.03–0.07, and the corresponding reasonable elastic stiffness of steel dampers is (0.2–0.5) Ks that is the stiffness of the structural standard story, and the proposed MoS2 sliding bearing presents remarkable low-friction characteristic with a friction coefficient of 0.04–0.05. The appropriate steel dampers can reduce the isolation layer drift without obviously increasing the acceleration. The low-frequency components in the ground motion significantly increase the isolation layer drift, while the high-frequency components cause the superstructure acceleration to show a K-shaped distribution along the height. Moreover, the proposed isolated system can be effectively used for structural protection under multi-dimensional earthquakes, the sliding additional layer on the roof can be considered as the second defense line in the structural seismic design, and the seismic energy the superstructure bears can directly estimate the seismic isolation effect that is consistent with the analysis result of dynamic response.

Observation of interlayer plasmon polaron in graphene/WS2 heterostructures

Harnessing electronic excitations involving coherent coupling to bosonic modes is essential for the design and control of emergent phenomena in quantum materials. In situations where charge carriers induce a lattice distortion due to the electron-phonon interaction, the conducting states get “dressed", which leads to the formation of polaronic quasiparticles. The exploration of polaronic effects on low-energy excitations is in its infancy in two-dimensional materials. Here, we present the discovery of an interlayer plasmon polaron in heterostructures composed of graphene on top of single-layer WS2. By using micro-focused angle-resolved photoemission spectroscopy during in situ doping of the top graphene layer, we observe a strong quasiparticle peak accompanied by several carrier density-dependent shake-off replicas around the single-layer WS2 conduction band minimum. Our results are explained by an effective many-body model in terms of a coupling between single-layer WS2 conduction electrons and an interlayer plasmon mode. It is important to take into account the presence of such interlayer collective modes, as they have profound consequences for the electronic and optical properties of heterostructures that are routinely explored in many device architectures involving 2D transition metal dichalcogenides.

Conversion and Active Control between BIC and Absorber in Terahertz Metasurface

A multifunctional switchable metamaterial device based on graphene, a gold layer, polyimide, vanadiµm dioxide (VO2), and the sapphire substrate is designed in this paper. The top layer consists of a gold wire, graphene, and two split-ring resonators with the same parameters. By adjusting the Fermi level of graphene, the regulation of BIC and quasi-BIC is realized, and the conversion between BIC and absorber is realized by adjusting the conductivity of VO2. When the device is converted into a wave-absorbing device with single-band absorption characteristics, the Fermi level of graphene at this time is 0.001 eV, the absorption peak at 0.820 THz is higher than 99.5%, and when the Fermi level of regulated graphene is 1 eV, the absorption peak at 0.667 THz is also higher than 99.5%. The peak frequency of the device is 0.640 THz when it converts to quasi-BIC. To the best of our knowledge, this is the first time that the conversion and regulation of BIC and absorber have been achieved using these two phase change materials. Moreover, by adjusting the parameters of the metamaterial structure, the working efficiency and frequency of BIC and absorber can be dynamically adjusted. The electric field distribution and surface current of metamaterials are further studied, and the physical mechanism of effective absorption and BIC is discussed. These results show that the metamaterials proposed in this paper have many advantages, such as terahertz absorption, BIC, and active device control, and are of great significance for developing terahertz multifunctional devices.

Impact of a floating flexible plate on the stability of double-layered falling flow

The hydrodynamic stability behavior of a two-layer falling film is explored with a floating flexible plate on the top layer surface. The stress balance at the surface is modeled using a modified membrane equation. There is an insoluble surfactant at the liquid-liquid interface of the flow system. The linear instability of perturbation waves is captured by numerically solving the generalized Orr-Sommerfeld eigenvalue problem using the Chebyshev spectral collocation technique. Four different types of linear stability modes are identified: surface mode (SM), interface mode (IM), interface surfactant mode (ISM), and shear mode (SHM). The floating flexible plate has an inferior impact on all the existing modes in the longwave zone. However, a significant influence is noticed for the finite wave numbers. The surface and interface wave instabilities can be suppressed in the smaller wavenumber zone by imposing higher structural rigidity and uniform thickness of the flexible plate. The stabilizing nature of the surface mode becomes more powerful when the top layer viscosity is dominant. A new interfacial instability emerges when the top layer is less viscous than the lower one. At moderate Reynolds numbers, the behavior of interface mode is different in two different zones mr<1 and mr>1, where m and r denote the viscosity and density ratio, respectively. Further, the unstable shear modes induced by the top and bottom layers are detected under the low inclination angles with a strong inertia force. The occurrence of the shear modes requires the viscosity and density of the lower layer to be much higher than those of the upper layer. The influence of characteristic parameters of the flexible plate on the lower layer shear mode is not very sensitive. Finally, the competition between the different modes for dominance of stability boundaries is also discussed.

Overestimated Fog-Top Entrainment in WRF Simulation Leading to Unrealistic Dissipation of Sea Fog: A Case Study

Entrainment at the top of the planetary boundary layer (PBL) is of significant importance because it controls the upward growth of the PBL height. An option called ysu_topdown_pblmix, which provides a parameterization of fog-top entrainment, has been proposed for valley fog modeling and introduced into the YSU (Yonsei University) PBL scheme in the Weather Research and Forecasting (WRF) model. However, enabling this option in simulations of sea fog over the Yellow Sea typically results in unrealistic dissipation near the fog bottom and even within the entire fog layer. In this study, we theoretically examine the composition of the option ysu_topdown_pblmix, and then argue that one term in this option might be redundant for sea-fog modeling. The fog-top variables are employed in this term to determine the basic entrainment in the dry PBL, which is already parameterized by the surface variables in the original YSU PBL scheme. This term likely leads to an overestimation of the fog-top entrainment rate, so we refer to it as redundant. To explore the connection between the redundant term and unrealistic dissipation, a widespread sea-fog episode over the Yellow Sea is employed as a case study based on the WRF model. The simulation results clearly attribute the unrealistic dissipation to the extra entrainment rate that the redundant term induces. Fog-top entrainment is unexpectedly overestimated due to this extra entrainment rate, resulting in a significantly drier and warmer bias within the interior of sea fog. When sea fog develops and reaches a temperature lower than the sea surface, the sea surface functions as a warming source to heat the fog bottom jointly with the downward heat flux brought by the fog-top entrainment, leading the dissipation to initially occur near the fog bottom and then gradually expand upwards. We suggest a straightforward method to modify the option ysu_topdown_pblmix for sea-fog modeling that eliminates the redundant term. The improvement effect of this method was supported by the results of sensitivity tests. However, more sea-fog cases are required to validate the modification method.

Dual mode spin to charge conversion using inverse spin Hall effect in NiFe/FeMn/NiFe multilayer thin films

Microwave devices with more than one operating frequency and their ease of tunability are of great importance for high-frequency information processing. Magnetic thin films offer an unparalleled advantage of engineering different microwave bands that can be precisely tailored and reconfigured externally. Here, novel trilayer structures consisting of NiFe/FeMn/NiFe with varying antiferromagnetic FeMn layer thickness have been investigated by exploring their ferromagnetic resonance (FMR) properties and inverse spin Hall effect (ISHE) responses. Two-step magnetic hysteresis loops are observed for higher FeMn thickness (t ⩾ 12 nm), where the bottom NiFe layer shows a comparatively more significant shift due to the presence of strong interfacial exchange coupling. FMR study reveals two resonant modes associated with the two ferromagnetic layers, which are distinguishable for higher thicknesses of FeMn or at high excitation frequencies. The choice of FeMn thickness determines the operating frequencies, which can be finely tailored by optimizing the FeMn thickness. Gilbert damping parameter is found to be in the range of 0.009–0.012 where the presence of exchange bias adds to the the scattering mechanisms. Prominent ISHE responses are obtained from the bottom NiFe layer as compared to the top NiFe layer. Variation of FeMn thickness also shows a strong influence on the spin pumping ( Vsp ), and perpendicular anisotropic magnetoresistance ( VAMR⊥ ) components. The results are correlated with the efficiency of spin flow and spin-to-charge conversion of the FeMn layer. Our systems can be used as an emerging alternative for microwave detectors and microwave energy harvesters.

Efficient nitrogen removal from mainstream sewage in tidal flow constructed wetlands: Targeted migration and conducive spatial distribution for pollutants removal

The tidal flow constructed wetland (TFCW) effectively removes nitrogen from mainstream wastewater but encounters limitations in denitrification, resulting in the accumulation of nitrate and nitrite nitrogen (NOx--N). In this study, we investigated the spatial distribution characteristics of pollutants and migration-transformation processes within the TFCW using the stratified analysis theories proposed. The results indicated that during the influent stage, 82.60 % of ammonia nitrogen (NH4+-N) and 87.77 % of COD were adsorbed by the top and middle layers. In the drain stage's oxygen-rich environment, microorganisms and atmospheric oxygen oxidized NH4+-N to NOx--N, achieving in-situ regeneration of NH4+-N adsorption sites. Furthermore, 61.87 % of the NOx--N was washed into the bottom in the next influent stage, subsequently adsorbed by the biofilm, and finally reduced to gaseous nitrogen using carbon source as the electron donor at the drain stage. Consequently, inconsistent locations of carbon source and NOx--N were identified as limiting factors for denitrification in TFCW. Based on this, the study designed a two-way influent tide flow constructed wetland (TTFCW) by altering the influent pattern. It facilitated targeted carbon source addition for denitrification, resulting in a 3.30-fold improvement in actual carbon source utilization efficiency of TFCW. Ultimately, this approach resulted in a notable increase in NOx--N removal rate by 64.51 %, accompanied by a 28.32 % reduction in accumulation levels. This study fills the research gap in the internal distribution and migration-transformation of pollutants within TFCW, providing methods support for enhancing nitrogen removal in TFCW and ideas for denitrification in mainstream wastewater.

Investigation Of Coastalock Performance On A Breakwater With Porous Core

Hard stabilization methods have traditionally been employed to mitigate coastal erosion. Concrete armour is widely used due to its high level of dependence, robustness, ease of production and cost effectiveness (Cooke et al., 2020; Pikey and Cooper, 2012). It is inevitable that coastline ‘armouring’ will continue to rise because of the growing human population and urbanization, desire for and value of coastal property, opposed to predicted climate change (Chapman and Underwood, 2011). The environmental impact of such 'armouring' on coastal systems can be detrimental, resulting in a degradation or destruction of habitats and the loss of ecologically trivial species (Gittman et al., 2015). The CoastalockTM, a single-layer armour unit, aims to blend coastal protection with marine habitat creation. This armour unit is designed to mimic inter- and sub-tidal habitats, with chemical composition of substrate and micro and macro features that provide niches for various species. The key feature of CoastalockTM is the cavity that is integrated into the design, that caters to diverse marine life needs depending on its orientation (ECOncrete Tech Ltd., 2019). CoastalockTM's hydraulic performance is under research. Preliminary tests conducted in the Hydraulic Engineering Laboratory (HEL) of the Technical University of Delft (TUD) on a 2V:3H impermeable slope in deep water conditions highlighted that with tight placement of the units significant pressure gradients across the top layer led to damage. The introduction of spacings between units for enhanced permeability improved stability significantly (Gutiérrez et al., 2023). A redesign of the unit was proposed incorporating protrusions to enforce the spacings between the blocks (Molenkamp, 2022). This research focuses on evaluating the influence of a porous core on the hydraulic performance of a CoastalockTM armour layer, specifically assessing its stability, overtopping, and reflection on a 2V:3H breakwater slope in deep water conditions—from the toe to just below the crest. A pivotal aspect of this research is the investigation of the impact of protrusions on the hydraulic performance. Furthermore, the study explores the influence of different toe configurations, aiming to comprehend the vulnerability of the armour layer to sliding. Toe scour falls outside the scope of this study.

Fabrication of hydrophobic surface from zein-based nanostructure and rosin to functionalize cotton textiles

A double-layer hydrophobic coating based on zein nanoparticles (ZNPs) and rosin was successfully developed as a simple and non-toxic process for textile functionalization. The bottom layer of the coating was a highly rough surface formed by the accumulation of zein nanoparticles prepared with an antisolvent method. The top layer was made of rosin to reduce the surface energy. The fabric treated with ZNPs and rosin (ZNPs/R/cotton) exhibited good hydrophobic behavior with a water contact angle (WCA) of 131.5 ± 2.3° and the hydrophobicity was long-lasting. The micromorphology and chemical composition of hydrophobic cotton fabric surface were characterized by scanning electron microscopy (SEM) and infrared spectroscopy (FTIR), respectively. The results demonstrated that zein and rosin deposited on the surface of the fabric to form a rough micro/nano-scale structure. The functional ZNPs/R/cotton retained excellent mechanical properties, air permeability and water vapor permeability. The practical application tests indicated that the fabric displayed good stain resistance ability. Even after 10 soaking cycles and 50 rubbing cycles, the fabric still retained good hydrophobic property with WCAs of 124.7 ± 2.9° and 90.3 ± 3.5°. This work offered a potential method for the clean production of functionalized textiles.

Double-layered cellulosic interfacial evaporator via upcycling of waste cotton fabrics for efficient solar desalination

Constructing efficient solar-driven interfacial evaporators (SDIEs) derived from biomass or waste stream materials (e.g., cellulose) is still challenging due to their less elaborate porous structure. Herein, we showed waste cotton fabrics could be dissolved and regenerated into aerogels with tunable channels suitable for constructing a double-layered SDIE. The evaporator consists of a polypyrrol-coated top layer featuring vertical channels with larger pores and a hydrophilic bottom layer featuring smaller pores. With such design, the photothermal and pro-evaporative capabilities of the top layer was coupled with the strong capillary effect of the bottom layer to drive effective evaporation. A desirable evaporation rate of 3.20 kg m−2h−1, 80.0% solar-to-vapor conversion efficiency under 1 sun irradiation, and a reduced evaporation enthalpy of 962 J g−1 was achieved. The SDIE also exhibits high purification efficiency (exceeding 99%) during long-term operation of seawater desalination and shows great potential in treatment of waste streams of high salinity dyeing effluent. In summary, this work demonstrates a case of upcycling waste cotton fabrics for water desalination.

Sandwiched solar interfacial evaporation system: Integrating phase change material/hydrogel/NiCo2O4 nanoflower for superior desalination

Solar-driven interfacial evaporation is a kind of sustainable and eco-friendly method of water treatment to alleviate the global water crisis. Here we demonstrate a novel sandwiched solar interfacial evaporator integrating phase change material (PCM), sodium alginate hydrogel (SA), and NiCo2O4 nanoflower featuring superb evaporation and glorious thermal energy management to achieve efficient energy utilization and long-term evaporation stability. After being combined with filter paper, NiCo2O4 nanoflower composites are adopted as the light absorber on the top layer, which can achieve an absorption of about 96.5 % in the full spectral range. SA hydrogel has been used as an intermediate layer for rapid water supply to the evaporation interface and to prevent salt deposition. Under one sun irradiation (1 kW m−2), the evaporator exhibits a high evaporation rate (1.94 kg m-2h−1) and excellent endurance in the treatment of high salt-concentration water. In particular, benefiting from the rational combination of PCM, the water production reached up to 12.13 kg m−2, which is 2.23 kg m-2higher than that of the evaporator without PCM under natural solar irradiation for 9 h. This work presents a promising concept for maximally utilizing intermittent solar irradiation energy and prolonged salt-free deposition desalination.

Enhancing Bi2Te2.70Se0.30 Thermoelectric Module Performance through COMSOL Simulations

This research employs the COMSOL Multiphysics software (COMSOL 6.2) to conduct rigorous simulations and assess the performance of a thermoelectric module (TEM) meticulously crafted with alumina (Al2O3), copper (Cu), and Bi2Te2.70Se0.30 thermoelectric (TE) materials. The specific focus is on evaluating diverse aspects of the Bi2Te2.70Se0.30 thermoelectric generator (TEG). The TEM design incorporates Bi2Te2.70Se0.30 for TE legs of the p- and n-type positioned among the Cu layers, Cu as the electrical conductor, and Al2O3 serving as an electrical insulator between the top and bottom layers. A thorough investigation is conducted into critical parameters within the TEM, which include arc length, electric potential, normalized current density, temperature gradient, total heat source, and total net energy rate. The geometric configuration of the square-shaped Bi2Te2.70Se0.30 TEM, measuring 1 mm × 1 mm × 2.5 mm with a 0.25 mm Al2O3 thickness and a 0.125 mm Cu thickness, is scrutinized. This study delves into the transport phenomena of TE devices, exploring the impacts of the Seebeck coefficient (S), thermal conductivity (k), and electrical conductivity (σ) on the temperature differential across the leg geometry. Modeling studies underscore the substantial influence of S = ±2.41 × 10−3 V/K, revealing improved thermal conductivity and decreased electrical conductivity at lower temperatures. The findings highlight the Bi2Te2.70Se0.30 TEM’s high potential for TEG applications, offering valuable insights into design and performance considerations crucial for advancing TE technology.