Electrocatalytic water splitting offers a safe, trouble-free and high-purity alternative for hydrogen production, garnering considerable attention in recent times. However, the poor catalytic activity of currently used state-of-the-art catalysts due to sluggish reaction kinetics, combined with their reliance on costly and rare elements, prevents the widespread application of water-splitting technology. Thus, development of effective, inexpensive and durable electrocatalysts is of utmost importance and high priority for renewable energy systems. Herein, we demonstrate a combined approach of experimental and theoretical investigations of electrochemical water splitting using a novel trinuclear copper(ii) cluster [Cu3(L)(OAc)(Cl)2]& centerdot;3H2O (H3L = N,N '-bis[2-carboxybenzomethyl]-N,N '-bis[2-pyridylmethyl]-1,3-diaminopropan-2-ol; OAc = acetate) as an efficient bifunctional electrocatalyst for the hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). Construction of this cluster is achieved by the self-assembly approach upon incorporation of one & micro;:eta 1:eta 1-acetate and two & micro;:eta 2-benzoate functionalities through the [CuII(& micro;-O2CCH3)CuII] and [CuII(& micro;-O2CC6H5)CuII] units, respectively. The overall electronic environments of the Cu centers in this cluster are tuned and modulated by a synergistic combination of coordinated alkoxide, acetate, benzoate and chloride for expediting water-splitting reactions. Thorough electrochemical studies confirm enhanced bifunctional activity towards both the OER and HER with low overpotentials (eta) at 10 mA cm-2 (264 mV for the OER and 115 mV for the HER) and small Tafel slopes (65.01 mV dec-1 for the OER and 42.45 mV dec-1 for the HER). Detailed density functional theory (DFT) calculations indicate that the occurrence of adjacent active sites greatly supports facile formation of molecular O-O and H-H bonds, and their mechanistic aspects have been elucidated. Our experimental and theoretical findings clearly suggest that Cu-based efficient bifunctional water-splitting electrocatalysts can be developed by designing molecular systems with redox-flexibility and by locating water-activation sites close to each other, which lower the energy required to form molecular O-O and H-H bonds, making these processes more competent.
This study examines how public acceptance of an increase in water rate can be enhanced to support financially sustainable water services. Using survey data from 1665 individuals in Japan, we analyse how information provision and social capital affect willingness to pay (WTP) by focusing on use and non-use values. The results show that non-use values play a central role in shaping WTP. In particular, values related to financial sustainability, disaster preparedness, and reducing burdens on future generations significantly increase WTP, whereas altruistic concerns for low-income households do not. We also find that information provision alone does not increase WTP. Instead, prior knowledge of water services is associated with higher WTP, suggesting that information is effective only when it is already internalised. Moreover, certain types of information can reduce WTP, such as messages emphasising individual losses, decrease WTP among respondents with prior knowledge. Finally, social capital significantly influences WTP. Trust, reciprocity, and interactions with neighbours increase WTP, while participation in community activities negatively affects WTP. These findings highlight the importance of social and informational factors in designing policies to achieve socially acceptable water pricing.
Zinc secondary batteries are attractive energy storage systems because of their safety and material abundance. However, concentration inhomogeneity of zincate ions near the negative electrode often induces localized deposition and accelerates dendrite formation of zinc metal. Several methods for suppressing dendrite formation have been proposed and implemented, but separator structures have been shown to be effective in suppressing dendrite formation recently. In this study, ion distributions were estimated by using a two-dimensional diffusion-based simulation model to clarify the effect of separators alone in zinc secondary batteries. Separator structures with systematically varied pore sizes and pore spacing were examined in this model, and the temporal evolution of ion concentration fields during charge-discharge cycles was analyzed. The results show that not only the absolute values of pore size and pore spacing but also their relative spatial arrangement strongly affect the magnitude and persistence of concentration fluctuations near the electrode. In particular, even for non-uniform pore arrangements, structures with gradually varied pore sizes or spacing configurations that maintain an appropriate balance between adjacent regions effectively mitigate local concentration peaks and suppress concentration inhomogeneity. These results provide physically based design guidelines for separator structures aimed at reducing dendrite-induced degradation in zinc secondary batteries.
This study aimed to investigate the association between ambient humidity and intraocular pressure (IOP), including potential nonlinear relationships and delayed effects of humidity on IOP. A time-series analysis was conducted using outpatient data collected at Shimane University Hospital between 2018 and 2023. Meteorological data on the days of IOP measurements were obtained from the Japan Meteorological Agency using data from the nearest weather station in Izumo City. Nonlinear relationships between humidity and IOP were evaluated using generalized additive models (GAMs), and delayed cumulative effects of humidity on IOP were assessed using distributed lag nonlinear models (DLNMs). The dataset included 1,269 observation days and 33,979 IOP measurements, comprising 8,756 measurements over 921 days in the non-glaucoma group and 25,173 measurements over 1,182 days in the glaucoma group. In GAM, nonlinear associations between humidity and IOP were not significant in any group. In the glaucoma group, cumulative exposure to relative humidity of 61–69
This paper proposes a new configuration of single-layer dual-band dual-beam reflectarray antenna (RA) that can form two beams to two directions at two frequency bands, depending on the polarization of incident wave from primary horn antenna. To our best knowledge, such dual-beam RAs have not been realized at dual bands yet. To design the element geometries at two bands independently, the proposed RA consists of the two orthogonally arranged dipole elements for a lower band and the Jerusalem cross elements for a higher band. As an example, we present a single-layer dual-beam RA at 15/28-GHz bands, which is constructed by dipoles and Jerusalem cross elements designed to form two beams with a directional difference of 10 degrees at 15 GHz and 5 degrees at 28 GHz. The effectiveness of the proposed RA is proven through the comparison of radiation characteristics between EM-simulated and measured ones.
