Good Water Research Articles

Clustering-triggered emission mechanism of carboxymethyl β-cyclodextrin aqueous solution and efficient recognition of Fe3+ in mixed ions.

Most nonconventional luminogens enjoy good water solubility and biocompatibility, showing unique application prospects in fields like biological imaging. Although clustering-triggered emission (CTE) mechanisms have been proposed to explain such emissions, the have not been thoroughly elucidated, which limits their development and application. Here, the photoluminescence properties of carboxymethyl β-cyclodextrin (CM-β-CD) aqueous solution are utilized to further investigate the effects of changes in concentration, in order to elucidate the emission mechanism through cryo-transmission electron microscopy (cryo-TEM), small-angle X-ray scattering (SAXS), molecular interaction analysis, and theoretical calculation. The results showed that the size distribution, morphology, and distance between water aggregates were successfully correlated with the cluster emission centers. The emission mechanism of nonconventional luminogen solutions was more clearly and intuitively elucidated, which has a promoting effect on the emission and application of this field. It is interesting that temperature-dependent emission spectra show the blue-shift phenomenon of PL with increasing excitation wavelengths. Moreover, due to its strong static quenching effect for Fe3+, CM-β-CD can efficiently detect Fe3+ in mixed-ion aqueous solutions. It provides a strategy to clarify the CTE mechanism of nonconventional luminogen solutions more clearly and its application of mixed-ion detection.

Optimizing modified natural rubber in starch-based hydrogels: A cost-effective approach for high-performance sustainable slow-release fertilizer coatings

Effective compatibility between natural rubber (NR) and cassava starch (CSt) is crucial for enhancing the water swelling and retention properties of CSt/NR-based hydrogels. In this study, NR was modified by grafting glycidyl methacrylate (NR-g-GMA, NRG) at 3, 6, and 9 parts per hundred rubber (phr) for blending with CSt. Subsequently, CSt was grafted with acrylamide (AM), crosslinked with N,N′ − methylene-bis-acrylamide (MBA), and interpenetrated with NRG to produce CSt-g-PAM/NRG hydrogels. The resulting CSt-g-PAM/NRGx (x = phr of GMA) hydrogels were characterized using FTIR, XRD, TGA, tensile testing, and water swelling measurements. Results revealed that CSt-g-PAM/NRG3 exhibited the highest equilibrium water swelling at 3300 %, surpassing CSt-g-PAM/NR (1430 %) and demonstrated the highest mechanical strength (0.92 MPa), desirable biodegradability (69 % at 30 days), and good water retention. These properties are attributed to the superior compatibility and stronger interactions between NRG and the CSt-g-PAM networks. Additionally, the WUHNRG3 (urea coated with CSt-g-PAM/NRG3 and wax layers) fertilizer demonstrated good biosafety, an acceptable slow-release rate (50.26 % at 30 days), and effectively promoted the growth of chili plants at a reasonable cost. This study demonstrates that modifying NR with optimal GMA content provides an effective CSt-g-PAM/NRG coating membrane, suitable for sustainable slow-release fertilizers and green agricultural practices.

Exploring the strength and durability of hemp fiber reinforced moringa bioresin composites for skateboard applications

The study aimed to develop and analyze bio-based composites, incorporating moringa bioresin and hemp fibers as reinforcing elements. The composites were fabricated using four weight percentage combinations of epoxy, moringa bioresin, and hemp fiber. The fabricated composites were characterized by their mechanical, thermal, water absorption, biodegradability, and morphological properties. The study revealed that the composite with the highest proportion of moringa bioresin (30 wt. %) exhibited better mechanical properties. Moreover, the flexural strength and Shore D hardness were impacted by both the matrix and reinforcing materials’ weight percentages. Thermal analysis showed that the composites had good thermal stability, while water absorption analysis indicated that the composites had good water resistance. Biodegradability analysis showed that the composites had a high rate of biodegradation, making them environmentally friendly. The distribution of reinforcing fibers within the matrix material was found to be uniform through the use of scanning electron microscope based morphological analysis. The results indicate that moringa bioresin and hemp fiber composites have the potential to be used as sustainable alternatives to petroleum-based composites in various applications.

A Green Synthesis of Au-Ag Alloy Nanoparticles using Polydopamine Chemistry: Evaluation of their Anticancer Potency Towards Both MCF-7 Cells and their Cancer Stem Cells Subgroup.

Limited chemotherapy efficacy and cancer stem cells (CSCs)-induced therapeutic resistance are major difficulties for tumour treatment. Adopting more efficient therapies to eliminate bulk-sensitive cancer cells and resistant CSCs is urgently needed. Based on the potential and functional complementarity of gold and silver nanoparticles (AuNPs or AgNPs) on tumour treatment, bimetallic NPs (alloy) have been synthesized to obtain improved or even newly emerging bioactivity from a combination effect. This study reported a facile, green and economical preparation of Au-Ag alloy NPs using biocompatible polydopamine (PDA) as a reductant, capping, stabilizing and hydrophilic agent. These alloy NPs were quasi-spherical with rough surfaces and recorded in diameters of 80 nm. In addition, these alloy NPs showed good water dispersity, stability and photothermal effect. Compared with monometallic counterparts, these alloy NPs demonstrated a dramatically enhanced cytotoxic/pro-apoptotic/necrotic effect towards bulk-sensitive MCF-7 and MDA-MB-231 cells. The underlying mechanism regarding the apoptotic action was associated with a mitochondria-mediated pathway, as evidenced by Au3+/Ag+ mediated Mitochondria damage, ROS generation, DNA fragmentation and upregulation of certain apoptotic-related genes (Bax, P53 and Caspase 3). Attractively, these Au-Ag alloy NPs showed a remarkably improved inhibitory effect on the mammosphere formation capacity of MCF-7 CSCs. All the positive results were attributed to incorporated properties from Au, Ag and PDA, the combination effect of chemotherapy and photothermal therapy and the nano-scaled structure of Au-Ag alloy NPs. In addition, the high biocompatibility of Au-Ag alloy NPs supported them as a good candidate in cancer therapy.

MXene@polydopamine/oxidized sodium alginate modified collagen composite aerogel as sustainable bio-adsorbent for heavy metal ion adsorption and solar driven water evaporation

The design of an environmentally friendly bio-adsorbent for the removal of heavy metal ions from aqueous media is a sustainable strategy to ensure water safety. Herein, a three-dimensional macroscopic aerogel with photothermal conversion and heavy metal wastewater treatment capability was designed using leather collagen, MXene@polydopamine and oxidized sodium alginate as raw materials, named as MPAC composite aerogel. The applicability of the developed MPAC composite aerogel in water evaporation and heavy metal wastewater treatment was studied. MPAC composite aerogel had good Cr(VI) adsorption capacity. This article focused on the study of adsorption kinetics, isotherms and thermodynamics. The adsorption equilibrium time of MPAC composite aerogel was 60 min, and the equilibrium adsorption capacity of MPAC composite aerogel for Cr(VI) reached 80.73, 100.80 and 112.86 mg/g when the initial Cr(VI) concentration was 30, 70 and 100 mg/L, respectively. The adsorption process of Cr(VI) by MPAC composite aerogel conformed to the two-level dynamics model and the Freundlich adsorption isotherm model, and was a spontaneous endothermic reaction. Additionally, the composite aerogel had good solar-driven water evaporation ability and could enhance the water evaporation rate of Cr(VI) solution. Furthermore, the MPAC composite aerogel had high adsorption performance for Cr(VI) under solar illumination conditions. This new aerogel has the advantages of low cost, environmental friendliness, strong adsorption capacity and photothermal conversion performance and is a promising heavy metal ion adsorbent.

Mass transfer and round-trip efficiency evaluation of unitized regeneration proton exchange membrane fuel cell during bi-directional mode switching cycle

Bi-directional mode switching is a crucial operation in unitized regenerative proton exchange membrane fuel cells (UR-PEMFC). Mass transfer plays a direct role in influencing the performance of both the fuel cell (FC) mode and the electrolytic cell (EC) mode, consequently impacting the round-trip efficiency (RTE). This study enhanced the three-dimensional two-phase model of UR-PEMFC by incorporating the mass transfer dynamics of the flow field. The round-trip efficiency (RTE) was systematically assessed throughout the bidirectional mode switching cycle. The results indicate that UR-PEMFC with triple-serpentine flow fields (TSF) performed well in FC mode, which was attributed to its good oxygen distribution uniformity and liquid water detachment capacity, in EC mode, its poor effective mass transfer coefficient and higher mass transfer resistance led to higher electrolytic energy consumption. However, UR-PEMFCs with TSF and parallel flow field (PFF) had better dynamic response performance during the bidirectional mode switching, and their voltage undershoot (overshoot) and response time were improved, which were attributed to uniform flow field structures. The UR-PEMFC reached optimum RTE operating at 0.1 A/cm2 in FC mode and 1.1 A/cm2 in EC mode, and the RTEs of the UR-PEMFCs with PFF and TSF were more advantageous, their highest RTEs were 36.62% and 36.30%, respectively. This study proposes two switching strategies to enhance the stability of URFC mode switching, offering a viable new approach for optimizing the flow field and improving overall performance.

Sustainability and water quality management in Chaltia Beel: Addressing ecological and public health challenges

This study evaluates the water quality of Chaltia Beel, a significant wetland in Murshidabad, West Bengal, India. Chaltia Beel serves as a crucial habitat for a variety of aquatic species and supports local communities through its use in agriculture and fisheries. The primary objective of this research is to assess the microbiological and chemical characteristics of the beel's water to determine its suitability for ecological and human use. Water samples were collected from three different sites within the beel during the post-monsoon season of 2023. The parameters analyzed include pH, temperature, total dissolved solids (TDS), turbidity, dissolved oxygen (DO), nitrate (NO3), phosphate (PO4), ammoniacal nitrogen, total alkalinity, and total coliform bacteria. Standard methods prescribed by the American Public Health Association (APHA) and the Indian Standards Institution (ISI) were employed for the analyses. The results indicate that the pH values (7.74 to 7.77) are within the neutral range, which is favorable for most aquatic life. The temperature of the water (28.1°C to 28.2°C) is stable and conducive to the ecosystem. TDS levels (398 mg/l to 406 mg/l) are within acceptable limits, though continuous monitoring is recommended to detect any potential increases. Turbidity levels (1.1 NTU to 1.4 NTU) are low, indicating good water clarity. DO levels (6.3 mg/l to 6.6 mg/l) are adequate to support aerobic aquatic organisms. Nitrate levels were consistently below 0.5 mg/l, suggesting minimal agricultural runoff impact. However, phosphate levels (1.38 mg/l to 1.41 mg/l) are relatively high, indicating a risk of eutrophication. Ammoniacal nitrogen levels (0.56 mg/l to 0.61 mg/l) are within acceptable limits but need monitoring to prevent potential toxicity. Total alkalinity (277.4 mg/l to 285 mg/l) provides a good buffering capacity, maintaining pH stability. Microbiological analysis revealed significant contamination with total coliform bacteria ranging from 190 to 204 CFU/100ml, which highlights potential health risks if the water is used for drinking or recreational purposes. The study concludes that while some water quality parameters of Chaltia Beel are within acceptable limits, others require attention to prevent environmental and health issues. Regular monitoring, pollution control, public awareness, habitat restoration, and sustainable practices are recommended to improve and maintain the water quality of Chaltia Beel. These efforts are essential for preserving the ecological health of the wetland and ensuring its continued benefit to the local communities.

Long-term Effect of Sodic Water for Irrigation on Soil Quality and Wheat Yield in Rice-Wheat Cropping System

Increasing scarcity of good quality water in many arid and semi-arid regions necessitates the use of poor quality groundwater for irrigation. Soil degradation resulting from alkali water irrigation has become a serious threat to soil health. In the present study, we conducted an investigation (2021-22) on the physicochemical properties (soil organic carbon, available Na, and available K) of sandy loam soil under a semi-controlled lysimeter. Wheat was grown as an experimental crop, which was irrigated with synthetic alkali waters having similar salts (total electrolyte concentration, TEC = 30 me L−1) and sodium adsorption ratio (SARiw 10 mmol L−1) but varying in residual sodium carbonate (RSC) are being continuously applied since 2004 (20 years). Five types of irrigation water having different levels of residual sodium carbonate comprised. (T1) best available groundwater, (T2) residual sodium carbonate water 1 (RSC- 5 me L–1), (T3) RSC water 2 (RSC 10 me L–1), (T4) RSC water 3 [RSC 10 treated with gypsum (RSC 10 neutralized to RSC 5 me L–1 with gypsum)] and (T5) RSC water 4 [RSC 10 treated with sulphur (RSC 10 neutralized to RSC 5 me L–1 with sulphur)]. Soil samples were collected after harvesting two wheat varieties (KRL 210 and HD 3226). Long-term irrigations with alkali water increased the available Na and K in the soil. Furthermore, soil organic carbon (SOC) decreased significantly with increasing alkalinity of irrigation water. Continuous irrigation with alkali water reduced grain yield of wheat by 31.7% over BAW. Moreover, the addition of gypsum and sulphuric acid has shown some capacity to partially restore soil properties, although not to the level of BAW. The majority of soil parameters under both crop cultivars showed a similar trend. The study's findings led to the conclusion that continuous applications of alkali water drastically degrade soil physicochemical properties. Partial neutralization of alkali water did not allow for the sustained existence of soil physicochemical properties. Consequently, it is recommended that the rate at which amendments are added to alkali water be adjusted to restore the decline in soil physicochemical properties.

Identify the seasonal differences in water quality and pollution sources between river-connected and gate-controlled lakes in the Yangtze River basin

The river-connected Dongting Lake (DT) and Poyang Lake (PY), and the gate-controlled Taihu Lake (TH) and Chaohu Lake (CH) are the four important lakes in the Yangtze River Basin. The comprehensive Water Quality Index (WQI), the Eutrophication Integrated Index (TLI(Σ)), and the Positive Matrix Factorization (PMF) model were employed to evaluate water quality and the contribution of pollution sources for these lakes. The results show that WQI for all lakes indicated generally good water quality, with DT scoring 73.52–86.18, the highest among them. During the wet season, the eutrophication degree of river-connected lake was medium, and that of gate-controlled lakes was high. The surface runoff and agricultural non-point sources are the main pollution sources for both types of lakes, but their impact is more pronounced in gate-controlled lakes during the wet season. The study provides evidence support for scientific understanding of water quality problems and management strategies in these areas.

5-Amino-1,2,4-triazol-3-one Degradation by Indirect Photolysis: A Density Functional Theory Study.

Sunlight irradiation induces formation of reactive oxygen species (superoxide, hydroperoxyl radical, singlet oxygen, etc.), which readily take part in degradation of environmental pollutants. Being a primary ingredient in a suite of insensitive munition formulations, NTO (5-nitro-1,2,4-triazol-3-one) can be released onto training range soils and reduced to ATO (5-amino-1,2,4-triazol-3-one) by soil bacteria or iron-contained minerals. ATO can be dissolved in surface water and groundwater due to its good water solubility and then undergo further decomposition. A detailed investigation of possible mechanisms for ATO decomposition in water induced by superoxide, hydroperoxyl radical, and singlet oxygen as pathways for ATO environmental degradation was performed by computational study at the PCM(Pauling)/M06-2X/6-311++G(d,p) level. Hydrolysis and degradation of ATO induced by superoxide are unlikely to occur due to the high activation energy or endergonicity of the processes. The hydroperoxyl radical causes rapid and reversible hydrogen transfer from ATO, while an attachment of the hydroperoxyl radical to ATO can induce decomposition of ATO, leading to its mineralization. Singlet oxygen shows a higher reactivity toward ATO than the hydroperoxyl radical. Decomposition of ATO was found to be a multistep process that begins with singlet oxygen attachment to the carbon atom of the C═N double bond. The intermediate that is formed undergoes recyclization, cycle opening, and sequential elimination of nitrogen gas, ammonia, and carbon(IV) oxide. Isocyanic acid, which arises intermediately, hydrolyzes into ammonia and carbon(IV) oxide. Calculated activation energies and high exergonicity of the studied processes support the contribution of singlet oxygen and the hydroperoxyl radical to ATO degradation into low-weight inorganic compounds in the environment.

Isotope and morphometrical evidence reveals the technological package associated with agriculture adoption in western Europe

This study aimed to reconstruct the environmental conditions and the crop management practices and plant characteristics when agriculture appeared in western Europe. We analyzed oak charcoal and a large number of cereal caryopsides recovered from La Draga (Girona, Spain), an early (5300 to 4800 cal. BC) agricultural site from the Iberian Peninsula. The carbon isotope discrimination (Δ13C) values of oak, the dominant forest species in the region, indicates prevalence of a wet climate at the site. Further, we reconstructed crop management conditions, achievable yield, and crop characteristics through the analysis of Δ13C, nitrogen isotope composition (δ15N), nitrogen content, and the reconstructed weight of wheat and barley caryopsides, following protocols developed by our team [Araus et al., Nat. Commun. 5, 3953 (2014)] and comparison of these parameters with present-day organic agriculture in the region. In parallel, a regional perspective was achieved through the study of wheat and barley grains of seventeen Neolithic sites from the western Mediterranean. The results suggest that rather than small-garden cultivation, a more extensive agriculture was practiced under good water availability and moderate manuring. Moreover, results from La Draga evidence that grain weight and spike morphology were comparable to contemporary cereals. Growing conditions and the prevalence of improved crop traits indicate that agriculture was fairly consolidated at the time it reached the western edge of Europe.

Fabrication of superamphiphobic micro-reentrant structures by inverted electrochemical deposition

Due to excellent oil resistance and shortened liquid-solid contact time, superamphiphobic surfaces have promising application prospects in oil transportation, and petroleum pollution control. Although superamphiphobic surfaces have been constructed on various substrates, there is still a lack of high-efficient methods for fabricating micro-reentrant structures on engineering metal substrates. This paper proposes a new method combining laser processing and inverted electrochemical deposition techniques to achieve high-efficient and large-scale fabrication of superamphiphobic surfaces on copper substrates. Firstly, micropillar array structures are constructed by laser processing, and the structures exhibit excellent superhydrophobicity after low surface energy modification. Then, inverted electrochemical deposition is performed after polishing the top of the array, and local angle of the gas/liquid interface can be controlled by adjusting the distance between the top of the micropillar and the electrolyte level, thus regulating micro-morphology of the roof structure. The influences of electrochemical deposition parameters on characteristics of the micro-reentrant structures are systematically investigated. Finally, superamphiphobic micro-reentrant structures (roof diameter > 190 μm, micropillar spacing <250 μm) with water and oil contact angles exceeding 150° are prepared after lowering the surface energy of the deposited structures. After anti-fouling, blowing, ultrasonic vibration, and tape adhesion tests, the prepared superamphiphobic micro-reentrant structures maintained good water and oil repellency, showing excellent chemical stability and durability. The research may provide a simple, efficient, and low-cost method for high-efficient constructing superamphiphobic surfaces on engineering metal substrates, enriching the fabrication techniques of micro-reentrant structures and facilitating their practical applications.

A sustainable zein-based adhesive for various substrates with improved adhesion and stability

Biomass-based adhesives are gaining attention as environmentally friendly alternatives to toxic petroleum-based adhesives. However, biomass-based adhesives exhibit poor adhesive properties and are highly susceptible to failure in humid environments. In this study, a zein-based adhesive with high adhesive strength and good water resistance was prepared by optimizing the solvent composition and adding tannic acid. Adding 10 wt% acetic acid to an aqueous ethanol solvent increased the shear strength by 45.4 % to 3.09 MPa. Moreover, the addition of 6 wt% tannic acid improved the shear strength of the zein-based adhesive in humid environments from 0.63 to 1.58 MPa. The tannic acid-reinforced zein-based adhesive exhibited good adhesive strength in both humid and dry environments, which was maintained for 30 days on glass, and could be applied to a wide range of substrates. Moreover, the adhesive showed an antioxidant activity >94 %, excellent thermal stability, biocompatibility, and antibacterial effect. Therefore, this adhesive has great application prospects in medical, packaging, and other fields.

Tris-phenol phosphine oxide-based polyester loose nanofiltration membranes with a three-dimensional structure for efficient dye/salt separation

Loose nanofiltration (LNF) membranes prepared by hydroxyl monomers with good dye rejection and inorganic salt permeation properties have attracted significant attention for treating salt-containing textile wastewater. This study adopted interfacial polymerization (IP) method to fabricate a novel polyester LNF membrane, in which tris (4-hydroxyphenyl) phosphine oxide (THPPO) with a steric structure was employed as the solely aqueous monomer. To enhance the solubility and esterification reaction activity of THPPO, sodium hydroxide (NaOH) was specially adopted in aqueous phase, helping the development of the polyester selective layer. The findings demonstrated that the prepared ultrathin (30–38 nm) polyester selective layer exhibited a smooth surface with a negative charge. The optimal membrane LNF-0.05 exhibited a good water permeance of 20.8 L m−2h−1 bar−1, excellent rejection of anionic dyes (99.6 % for EBT, 99.3 % for CR, 98.8 % for DR 23, and 98.1 % for MB), and low rejection of monovalent salts (8.2 % for NaCl, 5.0 % for MgCl2), showing excellent EBT/NaCl mixture selectivity as high as 221. The performance stability of the membranes was partially testified by continuous filtration process. These results confirm the significant application potential of tris-phenol phosphine oxide-based polyester LNF membrane for treating saline textile wastewater.

Epsilon-poly-l-lysine inhibits biofilm formation and aids dispersion in Acinetobacter baumannii

Acinetobacter baumannii is a prominent hospital-associated bacterium whose eradication is increasingly challenging due to its remarkable ability to resist antibiotics. The most common illnesses caused by antibiotic-resistant A. baumannii are biofilm-associated. Therefore, novel methods to combat A. baumannii are urgently needed. Application of antimicrobial peptides (AMPs) is one of the avenues to be explored. Epsilon poly-l-lysine (ε-PL) is an antimicrobial peptide with low mammalian toxicity. It is commonly used as a food preservative and has advantages such as biodegradability, good water solubility, and thermal stability.Therefore, the antimicrobial activity of ε-PL against clinical isolates of A. baumannii was investigated. The effect of ε-PL on antimicrobial sensitivity was determined by broth dilution assay. The effect of ε-PL on biofilm formation and dispersion was studied using a crystal violet assay. The changes in the expression of quorum sensing related and virulence genes (abaI, csuE, pilT, bap, and luxI) were analyzed using qPCR by the Δ Δ CT method.All the A. baumannii clinical isolates (n = 28) tested, were resistant to multiple drugs. The treatment with ε-PL resulted in a significant (p < 0.05) reduction in the biofilm formation abilities of all the clinical isolates of A. baumannii. Also, ε-PL caused a significant (p < 0.05) decrease in the dispersion of preformed biofilms. The reduction in the biofilm formation could be attributed to the inhibition of autoinducer synthase (abaI) which is required for biofilm development in A. baumannii. Also, it could be due to altering of expression of biofilm-related genes like csuE, pilT, bap, and luxI. These results suggest that ε-PL could be effective in the elimination of A. baumannii biofilms and decreasing its virulence.

An innovative dual-organelle targeting NIR fluorescence probe for detecting hydroxyl radicals in biosystem and inflammation models

The hydroxyl radical (OH) is highly reactive and plays a significant role in a number of physiological and pathological processes within biosystems. Aberrant changes in the level of hydroxyl radical are associated with many disorders including tumor, inflammatory and cardiovascular diseases. Thus, detecting reactive oxygen species (ROS) in biological systems and imaging them is highly significant. In this work, a novel fluorescent probe (HR-DL) has been developed, targeting two organelles simultaneously. The probe is based on a coumarin-quinoline structure and exhibits high selectivity and sensitivity towards hydroxyl radicals (OH). When reacting with OH, the hydrogen abstraction process released its long-range π-conjugation and ICT processes, leading to a substantial red-shift in wavelength. This probe has the benefits of good water solubility (in its oxidative state), short response time (within 10 s), and unique dual lysosome/mitochondria targeting capabilities. It has been applied for sensing OH in biosystem and inflammation mice models.

Controllable morphology, excellent stability and non-equivalent doping-induced optical properties of Mn4+-activated K2NaScF6 red phosphor for high-quality warm WLED

Currently, Mn4+ activated fluoride red phosphor has been widely studied to improve the optical performance of white light-emitting diode (WLED) in the field of high-efficiency lighting and wide color gamut backlight display. In this paper, a series of red-emitting K2NaScF6:Mn4+ phosphors are synthesized by a simple co-precipitation method with a non-equivalent substitution of Mn4+ for Sc3+ at room temperature. The crystal structure, morphology and elemental composition of K2NaScF6:Mn4+ phosphors prepared using different reaction conditions are systematically investigated. Interestingly, the K2NaScF6:Mn4+ phosphors exhibit narrowband red emission with low correlated color temperature (CCT), high color purity and short fluorescence lifetime. Compared to equivalent doping, the mechanism of short fluorescence lifetime caused by non-equivalent doping has also been systematically discussed. The optimal doping concentration is determined by setting a series of Mn4+ doping concentrations and the concentration quenching mechanism is analyzed. The crystal field strength (Dq), Racah parameters (B and C) and nephelauxetic ratio (β1) are calculated in detail to evaluate the crystal field environment of Mn4+ in K2NaScF6. The good water resistance of the as-prepared sample K2NaScF6:Mn4+ is verified by comparing with the commercially available phosphor K2SiF6:Mn4+. Moreover, the thermal stability is also analyzed by calculating the activation energy (Ea), chromaticity shift (ΔE) and chromaticity coordinate variation (CCV). Importantly, the as-packaged warm WLED (InGaN chip + YAG:Ce3+ + K2NaScF6:Mn4+) has excellent optical properties (CCT = 4082 K, color rendering index (CRI, Ra = 91.2) and luminous efficiency (LE) = 78.86 lm/W), and it exhibits good output stability at high drive currents. In summary, our work demonstrates that K2NaScF6:Mn4+ red phosphors possess a great potential application in warm WLED for the indoor lighting.

Smart-Adhesive, Breathable and Waterproof Fibrous Electronic Skins.

For the need of direct contact with the skin, electronic skins (E-skins)should not only fulfill electric functions, but also ensure comfort during wearing, including permeability, waterproofness, and easy removal. Herein, the study has developed a self-adhesive, detach-on-demand, breathable, and waterproof E-skin (PDSC) for motion sensing and wearable comfort by electrospinning styrene-isoprene block copolymer rubber with carbon black nanosheets as the sensing layer and liner copolymers of N, N-dimethylacrylamide, n-octadecyl acrylate and lauryl methacrylate as the adhesive layer. The high elasticity and microfiber network structure endow the PDSC with good sensitivity and high linearity for strain sensing. The hydrophobic and crystallizable adhesive layer ensures robust, waterproof, and detaching-on-demand skin adhesion. Meanwhile, the fiber structure enables the PDSC good air and water permeability. The integration of electric and wearable functions endows the PDSC with great potential for motion sensing during human activities as both the sensing and wearable performances.

Preparation of good fluidity coal water paste based on the modified compartment stacking theory

ABSTRACT Coal water paste (CWP) is a mixture of pulverized coal and water with a mass concentration of more than 70 wt%. CWP has a higher coal concentration than traditional coal water slurry (~60 wt%), so it can significantly improve the efficiency of gasification and combustion. However, the preparation and rheology of paste is extremely complicated due to its high concentration and material complexity. In this paper, to obtain the preparation method of CWP which could meet the engineering demands, the effects of coal particle size distribution, grading ratio, and type and amount of dispersant on rheology of CWP are investigated. Based on the modified compartment stacking theory, the improved preparation method of CWP has been proposed, which introduces the influence of coarse particle shape. The particle size ratio of coarse and fine particles is about 12, the particle size ratio of fine and ultra-fine particles is about 5, the optimal three-peak grading ratio is 6:1:3. The preferred dispersant is pure naphthalene dry powder (PNDP), and its addition amount is 1.4 wt%. The flow grade of CWP (71 wt%) could reach A without any other modifications or treatments.

Carboxymethylcellulose and rare earth metal cation self-assembly: Tunable encapsulation of carbon dots in a multifunctional transparent film

Due to their unique properties, carbon dots have attracted significant interest across diverse fields. However, obstacles such as uneven size distribution in the course of synthesis and excessive aggregation lead to fluorescence quenching during solidification process. Moreover, conventional doping procedures frequently yield carbon dot films with constrained functionality, inferior durability, and harsh environments, thereby restricting their practical applications. To address these issues, this study fabricates N-doped carbon dots via a straightforward hydrothermal approach and incorporates them into CMC films by metathesis with CeCl3·7H2O, resulting in a unique carbon dot-encapsulated film. This film overcomes the problem of fluorescence quenching caused by excessive aggregation of carbon dots and allows for size control by adjusting the concentration of Ce(III). The resulting film achieves extreme transparency and superior performance compared to existing UV-blocking films. In addition, the film exhibits exceptional resistance to acids and bases, bleaching, excellent mechanical properties, and good thermal and water stability. Based on these properties, the film achieves size-controlled in-situ photoluminescence, full UV shielding, Cu2+ ion detection, anti-counterfeiting, and information encryption. The water-processable and water-adhesive characteristics of CMC enable its use in real-life situations, opening the door to wider use of solid-state carbon dots for multifunctional and intelligent applications.