•Fe-Mn oxide was prepared via a new method of redox–precipitation and aging.•Fe was doped in MnO2 lattice and resulted in structural distortion.•The morphology of MnO2 material was transformed from ...nanowires to nanoparticles.•The mechanism of morphological evolution of the material was proposed.•The Fe-Mn oxides showed high activity for o-xylene catalytic oxidation.
Fe-MnO2 nanocomposite was prepared via a redox–precipitation method combined with a subsequent aging treatment at low-temperature. Various characterizations showed that Fe was incorporated into MnO2 lattice that changed the relative intensity of MnO2 crystal planes. Thus, the structural defect was formed and the anisotropic growth of the MnO2 crystallite phase was suppressed. As a result, the morphology of MnO2 was transformed from nanowires to nanoparticles. In addition, the catalytic property of Fe-MnO2 was significantly enhanced than that of pristine MnO2 for the complete oxidation of o-xylene. This work provides a simple and effective strategy for regulating MnO2 texture and activity.
Studies of evolutionary correlations commonly use phylogenetic regression (i.e., independent contrasts and phylogenetic generalized least squares) to assess trait covariation in a phylogenetic ...context. However, while this approach is appropriate for evaluating trends in one or a few traits, it is incapable of assessing patterns in highly multivariate data, as the large number of variables relative to sample size prohibits parametric test statistics from being computed. This poses serious limitations for comparative biologists, who must either simplify how they quantify phenotypic traits, or alter the biological hypotheses they wish to examine. In this article, I propose a new statistical procedure for performing ANOVA and regression models in a phylogenetic context that can accommodate high-dimensional datasets. The approach is derived from the statistical equivalency between parametric methods using covariance matrices and methods based on distance matrices. Using simulations under Brownian motion, I show that the method displays appropriate Type I error rates and statistical power, whereas standard parametric procedures have decreasing power as data dimensionality increases. As such, the new procedure provides a useful means of assessing trait covariation across a set of taxa related by a phylogeny, enabling macroevolutionary biologists to test hypotheses of adaptation, and phenotypic change in high-dimensional datasets.
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Designing nanostructure based robust catalyst for the electrochemical water splitting is the great task in the energy conversion field to accomplish high electrical conductivity, low ...overpotential and long lasting activity. Herein, the electrochemical overall water splitting is reported by using the hydrothermally synthesized binder free cobalt iron phosphate thin films on low cost stainless steel substrates as a conducting backbone for the first time. The effect of composition ratio variation of cobalt and iron was studied on the structural, compositional, morphological, and surface electronic properties by conducting various characterizations which results in amorphous hydrous cobalt iron phosphate having mesoporosity. The as synthesized cobalt iron phosphate having composition ratio (50:50 of Co:Fe) exhibits excellent electrochemical OER and HER catalytic water splitting performance. Best performing electrode exhibits smallest overpotentials of 251.9 mV and 55.5 mV for OER and HER respectively at 10 mA/cm2 current density. To split water molecule into the H2 and O2 by overall water splitting in same alkaline medium, the potential of 1.75 V was required after long duration (100 h) catalysis. Overall analysis confirms the cobalt iron phosphate thin films are outstanding and robust for the hydrogen production as clean renewable energy source.
Thermally induced phase separation technique has been widely applied to produce various commercial high-density polyethylene (HDPE) membranes based on the HDPE/diluent system. In this work, the ...crystallization behavior and morphological evolution of HDPE/liquid paraffin (LP) blends were systematically investigated by differential scanning calorimetry (DSC), dynamic thermomechanical analysis (DMA), two-dimensional small-angle X-ray scattering (2D-SAXS) and scanning electron microscope (SEM). It is found that the chain mobility of HDPE is promoted and the entanglement density reduces with the introduction of diluent LP. When the LP content is lower than 40%, the liquid diluent distributes randomly in HDPE melt, while as the LP content exceeds 40%, the diluent saturates the inter-molecular space of HDPE, resulting in the full growth of lateral lamellar dimension of PE crystal. On the other hand, the morphologies of HDPE/LP films change considerably with the diluent content. (1) LP content <20%: diluent lives directly in the inter-lamellar region; (2) 20% ≤ LP content ≤40%: diluent will be excluded into the inter-cluster region and leads to the formation of separated LP domains between PE clusters. (3) LP content >40%: diluent will be aggregated between the stacked clusters to create numerous interconnected LP domains which act as the pathways for the gas or liquid permeation after the removal of LP. Accordingly, we provide a new guidance for the condensed structure controlling and the development of PE membranes with diverse functionalities.
Schematic diagram of topological structures of HDPE/LP melt and the morphologies of HDPE films with different LP content. Display omitted
•The introduction of diluent changes the crystallization and morphology of HDPE.•Diluent lives directly in the inter-lamellar region as its content <20%.•Diluent is excluded into the inter-cluster region when it ranges from 20% to 40%.•Diluent is aggregated between the stacked clusters as its content >40%.
•The increase of salt concentration weakens the double-layer force and reduces the pressure barrier.•The effect of salt concentration on droplet convergence morphology was obtained.•The effect of ...salt concentration on the oscillation attenuation process was studied.•The presence of salt and fiber reduces the production of secondary droplets.
Fiber coalescence is an economical and effective technology for the treatment of oily wastewater. In this paper, the microscopic coalescence process of salt droplets on the fiber is studied using a high-speed camera and PIV, and the effect of salt on hydrodynamics and morphological evolution is discussed. The results show that the increase of salt concentration leads to a decrease of double layer force, a larger liquid bridge expansion, and a higher capillary wave propagation velocity. When the salt concentration is too high, the capillary wave propagation velocity decreases. A catchment region with a high velocity is formed near the traveling region of the capillary wave, and the velocity can reach 0.03 m/s. The attenuation coefficient of the oscillation process increases with the increase of salt content. By combining fiber and salt, the rate of droplet coalescence can be increased, and the production of secondary droplets can be reduced.
Copper is uniquely active for the electrocatalytic reduction of carbon dioxide (CO2) to products beyond carbon monoxide, such as methane (CH4) and ethylene (C2H4). Therefore, understanding ...selectivity trends for CO2 electrocatalysis on copper surfaces is critical for developing more efficient catalysts for CO2 conversion to higher order products. Herein, we investigate the electrocatalytic activity of ultrathin (diameter ∼20 nm) 5-fold twinned copper nanowires (Cu NWs) for CO2 reduction. These Cu NW catalysts were found to exhibit high CH4 selectivity over other carbon products, reaching 55% Faradaic efficiency (FE) at −1.25 V versus reversible hydrogen electrode while other products were produced with less than 5% FE. This selectivity was found to be sensitive to morphological changes in the nanowire catalyst observed over the course of electrolysis. Wrapping the wires with graphene oxide was found to be a successful strategy for preserving both the morphology and reaction selectivity of the Cu NWs. These results suggest that product selectivity on Cu NWs is highly dependent on morphological features and that hydrocarbon selectivity can be manipulated by structural evolution or the prevention thereof.
•Synchronous full-array aeroelastic wind tunnel tests of vibration and force are conducted using the high-speed photography technology.•The characteristics of wind-induced vibration response and the ...evolution of wind-induced vibration form are analyzed.
Research on wind-induced vibration of large-span flexible photovoltaic(PV) array only give wind-induced response analysis and vibration reduction measures, but ignore morphological evolution laws among arrays. In this study, an aeroelastic model of 3-span 5-row suspension cable flexible PV array was designed with considerations to similarity ratio relationship of a strict wind tunnel test. Synchronous full-array aeroelastic wind tunnel tests of vibration under different wind direction angles and wind speed were carried out. The responsible characteristics of the structural system were analyzed systematically by using variation modal decomposition. Results demonstrated that strong vibrations were observed in the single row of PV when the wind speed was above a critical value. The support designed between PV array can restrain the strong wind-induced vibration. The wind-induced vibration degrees of each row of PV array are different, but the laws are basically consistent. The first row in the direction of the incoming flow vibrates at a low frequency. The wind-induced vibration of PV panel is mainly random buffeting, the farther away from the wind field, the more obvious the torsion. The vibration energy of vertical displacement of the PV array changes from low-order mode to high-order mode with the increase of row number. The energy dissipation phenomena of high-frequency intervals at the fifth downwind row are more obvious.
The importance of knowing the phenomenon of moisture sorption and the microstructural evolution in lactose anomers, lies in being able to establish its applicability. Thus, the moisture sorption ...phenomenon of four types of lactose anomers (C-βL, S-βL, F-αL and C-αL∙H2O) was studied, constructing adsorption isotherms at three storage temperatures (15, 25 and 35 °C), and fitting the experimental data with four mathematical models (BET, GAB, Peleg and Caurie). The analysis of the adsorption isotherm data, showed that: (i) β-lactose anomers adsorb less moisture than α-lactose anomers. (ii) In β-lactose anomers, purity influences stability, keeping a broad range of water activities. (iii) Increasing the storage temperature reduces the water activity range in which the anomers are stable. (iv) Based on the R2 parameter at 15 °C the best fit was achieved by employing the GAB model for the four lactose isomers, Specifically, the R2 values were as follows: C-βL = 0.993, S-βL = 0.996, F-αL = 0.905, and C-αL∙H2O = 0.98. The morphological evolution of lactose particles studied by scanning electron microscopy (SEM) showed particles of irregular morphology in the α-lactose anomers. Commercial β-lactose anomer presented particles with irregular morphology and few with curved morphology, suggesting the presence α-lactose as contamination. The synthesized β-lactose anomer presented mostly curved particles, indicating its high purity. In β-lactose anomers, mutarotation into α-lactose was observed with increasing storage temperature.
•During storage βL presents greater stability (aw = 0.7) than αL∙H2O. (aw = 0.5).•Commercial βL contains impurities that cause instability compared to a pure system.•SEM analysis allows characterizing the crystalline structures of βL and αL∙H2O.•Temperature and relative humidity promote mutarotation of βL to αL∙H2O.
Quantitative research regarding the effects and contribution rates of both natural processes and human interventions on the long-term evolution of the Yangtze Estuary is currently insufficient. To ...address this, we employ the Mann-Kendall (M-K) test to analyze hydrological changes and utilize bathymetric maps from 1958 to 2019 to quantify erosion and deposition patterns. Subsequently, combined with the empirical orthogonal function (EOF) to separately identify the top three control factors and elucidate spatiotemporal characteristics of the main factors controlling the Yangtze Estuary's morphological evolution. The results showed that sediment load and runoff consistently rank within the top three with respective mean contribution rates of 40.5% and 19.4%. Sediment load prevails as the first control factor across all regions except for the North Passage, which experienced a transition from natural dominance to human domination in 1998. Notably, extremely events like the 1998 flood occupied more eigenweighting in the short term and progressed in ranking due to the strong channel-forming capacity. Regarding escalating human interventions, estuarine engineering projects affect estuarine shoals following initial deposition and subsequent erosion patterns. However, their influence tends to wane post-completion, often surpassed by natural processes. Specifically, since 2010, continuous navigation channel dredging has governed the morphological evolution of the North Passage. Additionally, sand mining targeting the Ruifeng Shoal has driven the post-evolution dynamics of the South Channel as the second control factor. Overall, this study enhances our understanding of the coupling driving mechanisms involving both natural processes and human interventions, thereby enabling improved strategies for future sustainable management in estuarine environments.
•Disclosed the spatiotemporal characteristics of the main factors controlling the Yangtze Estuary's morphological evolution.•Sediment load and runoff consistently rank within the top three controlling factors, exhibiting mean contribution rates of 40.5% and 19.4%.•Provides new insights into the coupling driving mechanisms of both natural processes and human interventions in morphological evolution.
In this paper, the evolution of martensitic morphology and hardening mechanism of 30MnSi steel quenched at atmospheric and 3, 4 GPa pressure were investigated using EBSD, Mössbauer, HR-TEM. The ...experimental results show that an integrated martensite of lath and grain-preferred plate is induced after high-pressure quenching, instead of the almost entirely lath martensite that arises from normal quenching. The intricate substructures of martensite, which include tangled dislocations, 60.0° twin boundaries formed by twin-related K–S variants, and {112} -type twins with nanoscale ω-Fe (hexagonal), are characterized in 3, 4 GPa-samples. As the quenching pressure rises, the dislocation density, the percentage of twin boundaries and the amount of {112} -type twins all exhibit an increasing trend. In order to clarify the nature of transformation twins, the ω-lattice mechanism for high-pressure quenching martensite was discussed. Furthermore, the hardness of 30MnSi steel is considerably increased from 480 HV (normal quenching) to 766 HV (4 GPa-sample), and the relationship between microstructure and hardening was established. Based on our findings, high-pressure quenching has proved to have promising applications in the extensive control of martensitic transformation.
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