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Free radicals are increasingly recognized as active intermediate reactive species that can participate in various redox processes, significantly influencing the mechanistic pathways of reactions. Numerous researchers have investigated the generation of one or more distinct photogenerated radicals, proposing various hypotheses to explain the reaction mechanisms. Notably, recent research has demonstrated the emergence of photogenerated radicals in innovative processes, including organic chemical reactions and the photocatalytic dissolution of precious metals. To harness the potential of these free radicals more effectively, it is imperative to consolidate and analyze the processes and action modes of these photogenerated radicals. This conceptual paper delves into the latest advancements in understanding the mechanics of photogenerated radicals. [ABSTRACT FROM AUTHOR]

Peak spring streamflow is triggered in the Canadian prairies with complex generation mechanisms. The study characterizes the generation mechanisms of peak spring streamflow and models the basin response to changing hydro-climatic basin conditions. Key hydro-climatic basin descriptors were defined and used to set criteria for identifying different flood generation mechanisms, associated with the historical floods at 109 Canadian prairie basins. The temporal and spatial heterogeneity of these mechanisms were investigated, and a t-copula model was used to model the dependence structure between the basin descriptors and peak spring streamflow. The study: (1) suggests seven basin descriptors for characterizing the generation mechanism of peak spring streamflow; (2) discloses four levels of wetness conditions and nine flood generation mechanisms in the Canadian prairies; and (3) highlights the advantages and challenges of probabilistically assessing the basin response (peak spring streamflow) in relevance to historical and hypothetical basin conditions. We deem these results enhance the characterization of flood generation mechanisms in the Canadian prairies and advance the risk estimation of peak spring streamflow. [ABSTRACT FROM AUTHOR]

Power generation technologies based on water movement and evaporation use water, which covers more than 70% of the Earth's surface and can also generate power from moisture in the air. Studies are conducted to diversify materials to increase power generation performance and validate energy generation mechanisms. In this study, a water-based generator was fabricated by coating cellulose acetate with carbon black. To optimize the generator, Fourier-transform infrared spectroscopy, specific surface area, zeta potential, particle size, and electrical performance analyses were conducted. The developed generator is a cylindrical generator with a diameter of 7.5 mm and length of 20 mm, which can generate a voltage of 0.15 V and current of 82 μA. Additionally, we analyzed the power generation performance using three factors (physical properties, cation effect, and evaporation environment) and proposed an energy generation mechanism. Furthermore, we developed an eco-friendly and low-cost generator using natural fibers with a simple manufacturing process. The proposed generator can contribute to the identification of energy generation mechanisms and is expected to be used as an alternative energy source in the future. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Distance Education (1672-0008) is the property of Zhejiang Open University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Soochow University Philosophy & Social Sciences Edition is the property of Soochow University and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Power generation technologies based on water movement and evaporation use water, which covers more than 70% of the Earth’s surface and can also generate power from moisture in the air. Studies are conducted to diversify materials to increase power generation performance and validate energy generation mechanisms. In this study, a water-based generator was fabricated by coating cellulose acetate with carbon black. To optimize the generator, Fourier-transform infrared spectroscopy, specific surface area, zeta potential, particle size, and electrical performance analyses were conducted. The developed generator is a cylindrical generator with a diameter of 7.5 mm and length of 20 mm, which can generate a voltage of 0.15 V and current of 82 μA. Additionally, we analyzed the power generation performance using three factors (physical properties, cation effect, and evaporation environment) and proposed an energy generation mechanism. Furthermore, we developed an eco-friendly and low-cost generator using natural fibers with a simple manufacturing process. The proposed generator can contribute to the identification of energy generation mechanisms and is expected to be used as an alternative energy source in the future.

This article presents a general-purpose model that enables efficient and accurate calculation of third-order nonlinear signals in surface acoustic wave (SAW) devices. This model is based on piezoelectric constitutive equations combined with perturbation theory, which can be analyzed by full finite element method (FEM). For validation, third-order harmonic (H3) responses and intermodulation distortions (IMD3) in SAW resonators are simulated, and their calculation results fit well to experimental data in the literature. Then, the generation mechanisms of the third-order nonlinearity in SAW resonators are discussed. The dominant generation mechanisms for different nonlinear signals and the relation between electrode materials and H3 peak magnitude are revealed, which provides an important guideline for further nonlinear suppression. [ABSTRACT FROM AUTHOR]

This study presents an analysis of the quasi-16-day wave (Q16DW) at three stations in the middle latitudes by using a meteor radar chain in conjunction with Aura Microwave Limb Sounder temperature data and MERRA2 (Modern-Era Retrospective Analysis for Research and Applications, Version 2) reanalysis data from 2008 to 2017. The radar chain consists of three meteor radar stations located at Mohe (MH, 53.5°N, 122.3°E), Beijing (BJ, 40.3°N, 116.2°E), and Wuhan (WH, 30.5°N, 114.6°E). The Q16DW wave exhibits similar seasonal variation in the neutral wind and temperature, and the Q16DW amplitude is generally strong during winter and weak around summer. The Q16DW at BJ was found to have secondary enhancement around September in the zonal wind, which is rarely reported at similar latitudes. The latitudinal variations of the Q16DW in the neutral wind and temperature are quite different. The Q16DW at BJ is the most prominent in both neutral wind components among the three stations and the Q16DW amplitudes at MH and WH are comparable, whereas the wave amplitude in temperature decreases with decreasing latitude. The quasi-geostrophic refractive index squared at the three stations in the period from 2008 to 2017 was revealed. The results indicate that the Q16DW in the mesosphere and lower thermosphere (MLT) at MH has a limited contribution from the lower atmosphere. Around March and October, the Q16DW in the troposphere at BJ can propagate upward into the MLT region, whereas at WH, the contribution to the Q16DW in the MLT region is largely from the mesosphere.

This article presents a general-purpose model that enables efficient and accurate calculation of third-order nonlinear signals in surface acoustic wave (SAW) devices. This model is based on piezoelectric constitutive equations combined with perturbation theory, which can be analyzed by full finite element method (FEM). For validation, third-order harmonic (H3) responses and intermodulation distortions (IMD3) in SAW resonators are simulated, and their calculation results fit well to experimental data in the literature. Then, the generation mechanisms of the third-order nonlinearity in SAW resonators are discussed. The dominant generation mechanisms for different nonlinear signals and the relation between electrode materials and H3 peak magnitude are revealed, which provides an important guideline for further nonlinear suppression.

[Display omitted] • Changes in the key flavor substances were elucidated during broad bean fermentation. • The core microorganisms during the fermentation process were identified. • The pathways and mechanisms for forming the key flavor substances were established. Pixian Douban (PXDB) is a popular Chinese condiment for its distinctive flavor. Broad bean fermentation (Meju) is the most important process in the formation of flavor substances. Key flavors were analyzed qualitatively and quantitatively, and metagenomic technology was applied to study the microbial diversity during broad bean fermentation. In addition, the main metabolic pathways of key flavors were explored. Results indicated that Staphylococcus_gallinarum was the main microorganism in the microbial community, accounting for 39.13%, followed by Lactobacillus_agilis , accounting for 13.76%. Aspergillus_flavus was the fungus with the highest species abundance, accounting for 3.02%. The KEGG Pathway enrichment analysis showed that carbohydrate metabolism and amino acid metabolism were the main metabolic pathways. Glycoside hydrolase and glycosyltransferase genes were the most abundant, accounting for more than 70% of the total number of active enzyme genes. A total of 113 enzymes related to key flavors and 39 microorganisms corresponding to enzymes were annotated. And Staphylococcus_gallinarum, Lactobacillus_agilis, Weissella_confusa, Pediococcus_acidilactici, Staphylococcus_kloosii, Aspergillus_oryzae, and Aspergillus_flavus played a key role in the metabolic pathway. This study reveals the formation mechanism of key flavors in fermented broad bean, it is important for guiding the industrial production of PXDB and improving product quality. [ABSTRACT FROM AUTHOR]

Recently, inorganic nanomaterials have received considerable attention for use in biomedical applications owing to their unique physicochemical properties based on their shapes, sizes, and surface characteristics. Photodynamic therapy (PDT), sonodynamic therapy (SDT), and chemical dynamic therapy (CDT), which are cancer therapeutics mediated by reactive oxygen species (ROS), have the potential to significantly enhance the therapeutic precision and efficacy for cancer. To facilitate cancer therapeutics, numerous inorganic nanomaterials have been developed to generate ROS. This mini review provides an overview of the generation mechanisms of ROS by representative inorganic nanomaterials for cancer therapeutics, including the structures of engineered inorganic nanomaterials, ROS production conditions, ROS types, and the applications of the inorganic nanomaterials in cancer PDT, SDT, and CDT.

Abstract: Seasonal variability and generation mechanisms of large nonlinear internal waves are reported, based on an analysis of 9 years of continuous observational data collected at nodes of the Ocean Networks Canada coastal observatory in the Strait of Georgia, Canada. About one thousand large nonlinear internal wave packets were identified. The timing of these packets suggests a very strong correlation with daily tides and fortnightly cycles. More waves are seen during the stronger tides of the fortnightly cycle but overall waves are seen in less than 40% of all days. Other wave characteristics show seasonal variations. In winter, when the pycnocline is weaker, both the spatial and temporal scales of internal waves are several times larger than summertime waves and wave amplitudes can approach 30 m. These waves are large enough vertically but small enough horizontally that standard acoustic Doppler current profiler (ADCP) processing algorithms present a strongly distorted view of wave shape and features. A specialized reprocessing of the beam velocities is used to correctly measure the wave velocity field and to determine wave propagation speed and direction. In addition to the previously known northward‐propagating waves in the Strait, we also found waves propagating in other directions and a noticeable correlation with winds, which may be a proxy for spatial variations in density and/or velocity shear. By considering wave propagation direction, relationship with tidal phase, and relationship with wind, three generation mechanisms were found. Two particularly interesting generation mechanisms involve waves radiating from the Sand Heads area. [ABSTRACT FROM AUTHOR]

Objective In this study we aim to identify the key (patho)physiological mechanisms and biophysical factors which impact the observability and spectral features of High Frequency Oscillations (HFOs). Methods In order to accurately replicate HFOs we developed virtual-brain/virtual-electrode simulation environment combining novel neurophysiological models of neuronal populations with biophysical models for the source/sensor relationship. Both (patho)physiological mechanisms (synaptic transmission, depolarizing GABA A effect, hyperexcitability) and physical factors (geometry of extended cortical sources, size and position of electrodes) were taken into account. Simulated HFOs were compared to real HFOs extracted from intracerebral recordings of 2 patients. Results Our results revealed that HFO pathological activity is being generated by feed-forward activation of cortical interneurons that produce fast depolarizing GABAergic post-synaptic potentials (PSPs) onto pyramidal cells. Out of phase patterns of depolarizing GABAergic PSPs explained the shape, entropy and spatiotemporal features of real human HFOs. Conclusions The terminology “high-frequency oscillation” (HFO) might be misleading as the fast ripple component (200–600 Hz) is more likely a “high-frequency activity” (HFA), the origin of which is independent from any oscillatory process. Significance New insights regarding the origins and observability of HFOs along depth-EEG electrodes were gained in terms of spatial extent and 3D geometry of neuronal sources. [ABSTRACT FROM AUTHOR]

Simultaneously with the fact that vehicle industry has been able to lower the noise emission from driving vehicles, tire/pavement noise has become the most significant source of traffic noise. In order to reduce it, low noise surfaces are seen as a practical solution. One of these types of surfaces may be elaborated with bituminous mixtures with crumb tire rubber added to the binder in high content by a wet process. However, the generation mechanisms involved in the tire/pavement sound and the reasons of the noise attenuation achieved with these mixtures are not so clear. This study analyses the different generation mechanisms that take place in the tire/pavement sound generation in these crumb tire rubber pavements. The surface properties of the in-service pavement, which are most important in controlling the acoustic performance (texture, acoustic absorption and dynamic stiffness or mechanical impedance), have been measured for the characterization of a test track constructed with and without crumb tire rubber. After results correlation of these surface characteristics in a pavement with crumb tire rubber added by a wet process, it seems that the parameters of roughness and texture could have a relevant role in the global tire/pavement sound emission, whereas dynamic stiffness influence is relatively minor. [ABSTRACT FROM AUTHOR]

• We investigated microseisms induced by Kalmaegi with multi-instrument observations. • A novel frequency-domain beamforming method was proposed to track microseism source. • Kalmaegi generated microseisms with source trailing behind only while moving fast. • Microseisms observed at the ocean bottom seismometers were dominated by Kalmaegi. • Coastal generated microseisms cannot propagate effectively across the ocean basin. The typhoon-generated microseisms, originating from the complex energy coupling and transferring among the Atmosphere-Ocean-Solid Earth spheres, can be detected remotely by seismometers as the strongest ambient seismic noise. The lack of in situ observations during the passage of typhoons has hampered numerical modeling of wind fields and ocean waves, and limited our understanding of the generation mechanisms of microseisms associated with typhoons. Here we present a comprehensive investigation of microseisms generated by typhoon Kalmaegi (September 2014) based on multiple-instrument constraints from observations including terrestrial and ocean-bottom seismic stations as well as ocean buoys. To understand the generation mechanisms, we apply an improved frequency-domain beamforming method to seismic array data leading to successful location of double-frequency (DF) microseism source regions. For comparison, we calculate the typhoon-induced ocean waves and theoretical source regions of the DF microseisms using the coupled ocean–atmosphere–wave–sediment transport modeling system with validation by ocean buoy observations. Both observations and numerical modeling results reveal two different generation mechanisms for typhoon-induced DF microseisms during the lifespan of Kalmaegi. When over the Philippine Sea, the DF microseisms were generated mainly by opposing ocean waves from two distinct storms. After Kalmaegi entered the South China Sea, the DF microseisms were generated mainly by the fast-moving typhoon with source regions just trailing behind, with the minimum frequencies determined by the typhoon translation speed. DF microseisms generated in coastal source regions were not detected by ocean bottom seismometers, suggesting that DF microseisms might not effectively propagate across the ocean-basin seafloor covered by thick sediments, owing to severe seismic attenuation and spreading losses. This information is crucial for the use of DF microseisms for future tracking and monitoring of typhoons. [ABSTRACT FROM AUTHOR]

In the paper, we use the nonlinear multiscale approach of physical mesomechanics to demonstrate that the scales of local crystal structure curvature in solids play a fundamental role in the generation of strain-induced defects and cracks. It is shown that strain-induced defects arise at the interfaces of 2D planar and 3D crystal subsystems by the mechanism of 'laser pumping' and cracks nucleate as structural phase decay in the zones of crystal structure curvature where the nonequilibrium thermodynamic potential or so-called Gibbs energy is higher than zero. Nonlinear fracture mechanics eliminates the problem of singularity 1/ r in equations of crack growth but requires accounting for local lattice curvature at the crack tip. [ABSTRACT FROM AUTHOR]

The generation mechanisms of convective gravity waves in the stratosphere are investigated in a three-dimensional framework by conducting numerical simulations of four ideal storms under different environmental conditions: one un-sheared and three constant low-level sheared basic-state winds with the depth of the shear layer of 6 km and the surface wind speeds (U) of 8, 18, and 28 m s, using the Advanced Regional Prediction System (ARPS) model. The storms simulated under the un-sheared (U = 0 m s), weakly sheared (U = 8 and 18ms), and strongly sheared (U = 28ms) basicstate winds are classified into single-cell, multicell, and supercell storms, respectively. For each storm, the wave perturbations in a control simulation, including nonlinearity and microphysical processes, are compared with those in quasi-linear dry simulations forced by diabatic forcing and nonlinear forcing that are obtained from the control simulation. The gravity waves generated by the two forcing terms in the quasi-linear dry simulations are out of phase with each other for all of the storms. The gravity waves in the control simulation are represented by a linear sum of the wave perturbations generated by the nonlinear forcing and diabatic forcing. This result is consistent with the results of previous studies in a two-dimensional framework. This implies that both forcing mechanisms are important for generating the convective gravity waves in the three-dimensional framework as well. The characteristics of the three-dimensional gravity waves in the stratosphere were determined by the spectral combination of the forcing terms and the wave-filtering and resonance factor that is determined from the basic-state wind and stability as well as the vertical structure of the forcing. [ABSTRACT FROM AUTHOR]

• Magnitude of the 26 s and 28 s signals are like the Gutenberg-Richter relation. • Interval time distributions of the 26 s and 28 s signals conform to a Poisson process. • Swell transiently affects the 26 s signal; primary microseism modulates both signals. • Both signals are generated by resonance of underground fluid-filled conduits. • Reservoir networks compose of lots of tiny cracks without a characteristic scale. The earth is a dynamic planet with abundant vibrating processes. Besides the earthquakes, volcanoes and other activities, there is a special type of sources called persistent localized microseismic source (PL) with long-period almost harmonic signals and fixed location. The 26 s (0.038 Hz) and 28 s (0.036 Hz) tremors in the Gulf of Guinea are two typical PL sources in the world, but their generation mechanisms are still enigmatic. Moreover, understanding behaviors of these two sources helps to reduce their interference to ambient noise tomography. We implemented an algorithm to detect events in the PL signals for the past 30 years, and then performed statistical analysis of magnitude-cumulative number (M-N) and interval time-number (T-N). We found that the magnitude distribution is similar to the Gutenberg-Richter relation (G-R relation or power law) and the distribution of interval between events is consistent with a Poisson process. We propose that the two sources are probably related to underground complex crack networks featuring fractal characteristics, and are dominantly driven by temporally random dynamic processes. However, ocean swell might affect the 26 s source occasionally while the primary microseism seems to modulate the two PL sources. [ABSTRACT FROM AUTHOR]

A model has been developed to describe the turbulent structure of the surface layer which takes into account the differences in the scales of turbulent vortices generated by different mechanisms. We consider the shear of the drift current, nonlinear effects of surface waves, and their breaking as the main sources of turbulent energy. The power spectrum is divided into ranges with respect to the scales. The equation system for each range is solved numerically. The modeling results are compared with the experimental data and with other currently known models. The advantages of the suggested approach are demonstrated. [ABSTRACT FROM AUTHOR]

Abstract: A series of pristine block-and-ash flow deposits from the May–June 2006 eruption of Merapi represent an exceptional record of small-volume pyroclastic flows generated by gravitational lava-dome collapses over a period of about two months. The deposits form nine overlapping lobes reaching ~7 km from the summit in the Gendol River valley on the volcano''s southern flank, which were produced by successive flows generated during and after the major dome-collapse event on June 14. Both, single pulse (post-June 14 events) and multiple-pulse pyroclastic flows generated by sustained dome collapses on June 14 are recognised and three types of deposits, spread over an area of 4.7 km², are distinguished, totalling 13.3×106 m3: (1) valley-confined basal avalanche deposits (11.7×106 m3) in the Gendol River valley, (2) overbank pyroclastic-flow and associated surge deposits (1.4×106 m3), where parts of the basal avalanche spread laterally onto interfluves and were subsequently channeled into the surrounding river valleys and (3) dilute ash-cloud surge deposits (0.2×106 m3) along valley margins. Variations in the distribution, surface morphology and lithology of the deposits are related to the source materials involved in individual pyroclastic-flow-forming events and varying modes of transport and deposition of the different flows. Inferred flow velocities of the largest block-and-ash flows generated on June 14 vary from 43.8–13.5 m/s for the basal avalanche and from 62.6–24.2 m/s for the ash-cloud surge. The minimum temperatures range from 400 °C for the basal avalanche to 165 °C for the overlying ash cloud. Due to the potential of being re-channeled into adjacent river valleys and flowing laterally away from the main river channel, the overbank pyroclastic flows are considered the most hazardous part of the block-and-ash flow system. The conditions that lead to their development during flow transport and deposition must be taken into account when assessing future pyroclastic flow hazards at Merapi and similar volcanoes elsewhere. [Copyright &y& Elsevier]

Recently, inorganic nanomaterials have received considerable attention for use in biomedical applications owing to their unique physicochemical properties based on their shapes, sizes, and surface characteristics. Photodynamic therapy (PDT), sonodynamic therapy (SDT), and chemical dynamic therapy (CDT), which are cancer therapeutics mediated by reactive oxygen species (ROS), have the potential to significantly enhance the therapeutic precision and efficacy for cancer. To facilitate cancer therapeutics, numerous inorganic nanomaterials have been developed to generate ROS. This mini review provides an overview of the generation mechanisms of ROS by representative inorganic nanomaterials for cancer therapeutics, including the structures of engineered inorganic nanomaterials, ROS production conditions, ROS types, and the applications of the inorganic nanomaterials in cancer PDT, SDT, and CDT., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Zhang, Zhu, Huang, Ding, Ruan and Shen.)