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Abstract It is essential to understand the modification mechanism of hydrophobicity nano-CaCO3 to their potential application in different fields of chemistry. However, the water absorption of hydrophobicity nano-CaCO3 is seldom studied. In this study, Raman, BET and TGA experiments were performed on nano-CaCO3 samples to obtain surfactants contents and microstructure characteristics. SEM, TEM and DSL results showed that the nano-CaCO3 modified by stearic acid and sodium stearate had larger particle size and smaller nanoclusters. In the water vapor adsorption test, the order of saturation adsorption capacity was nano-CaCO3(PCC) > nano-CaCO3 modified by sodium stearate(PCC-Sa-Na) > nano-CaCO3 modified by stearic acid(PCC-Sa), and XPS results showed that PCC-Sa had more hydrophobic groups than PCC-Sa-Na, which also explained that the hydrophobicity of PCC modified by stearic acid and sodium stearate was improved by increasing the hydrophobic bond on the surface of CaCO3 and reducing the hydrophilic groups. Our analysis provides a path for the design and the prediction of hydrophobicity of nano-CaCO3, which is the main focus of our work.

Abstract We present the observations of field‐aligned currents and the equatorial electrojet during the 23 March 2023 magnetic storm, focusing on the effect of the drastic decrease of the solar wind dynamic pressure occurred during the main phase. Our observations show that the negative pressure pulse had significant impact to the magnetosphere‐ionosphere system. It weakened large‐scale field‐aligned currents and paused the progression of the storm main phase for ∼3 hr. Due to the sudden decrease of the plasma convection after the negative pressure pulse, the low‐latitude ionosphere was over‐shielded and experienced a brief period of westward penetration electric field, which reversed the direction of the equatorial electrojet. The counter electrojet was observed both in space and on the ground. A transient, localized enhancement of downward field‐aligned current was observed near dawn, consistent with the mechanism for transmitting MHD disturbances from magnetosphere to the ionosphere after the negative pressure pulse.

Abstract The Ring current–Atmosphere interactions Model (RAM) with Self‐Consistent magnetic (B) field (SCB) combines a large‐scale kinetic model of ring current plasma with a three‐dimensional (3‐D) force‐balanced model of the terrestrial magnetic field. RAM‐SCB simulates the evolution of major ion species (H+, O+, and He+ by default) and electrons as a function of azimuth, radial distance, energy, and pitch angle. Simulation outputs include the Dst index, and pressure and differential flux of the modeled species, thus providing benefit as a science code and to inform surface charging hazard within the model domain. Version 2.2 of this open‐source simulation code has now—as of 8 August 2023—been made available for Runs‐On‐Request via the Community Coordinated Modeling Center.

We share the story of how we made this paper, the first executable paper in Heliophysics, through cross-disciplinary collaboration to highlight the benefits of our process. Executable papers are interactive documents that put a publication’s text inline with the code used in the research in a containerized environment with the data and dependencies needed to run the code. This approach enables readers to reproduce every step taken to arrive at the publication’s conclusions and to easily build upon and extend the work—all important components of open science. Open science is, broadly speaking, transparent and accessible knowledge that is shared and developed through collaborative networks. In this work, we present an adaptable workflow to compare magnetosphere models to spacecraft observations. It is one example of many other workflows that can be developed through collaborations between software developers and scientists in a move towards open science. Most of the authors are members of the Python in Heliophysics Community (PyHC), an international, multi-organizational community that serves as a knowledge base for performing Heliophysics research in the Python programming language. PyHC promotes the executable paper format as a supplemental tool to improve the reproducibility of publications and support open science. A key takeaway is that our collaboration made such a complex task an easy feat in the end. Additionally, the executable version of our paper makes it trivial for others to reproduce our work, and it gives them a better launching point to extend it. These facts underscore the success of our approach. In highlighting this new open science approach, we hope to be an example to our field and encourage this way of doing science.

The aim of this study was to reveal potential relationship between the main flow field around a shortfin mako shark and the surface morphology of shark skin. Firstly, a numerical simulation using the large eddy simulation (LES) method was conducted to obtain the main flow field around a smooth shark model. Then, the surface morphology characteristics of a shark (Isurus oxyrinchus) at different positions were characterized by scanning electron microscope (SEM), which showed that the morphology, riblet size, and density of scales at different positions on the shark were significantly different. At positions where the surfaces face into the water flow direction (i.e., nose and leading edge of fins), the scales were flat and round, with a lower density, and the pressure or wall shear stress (WSS) was greater. Scales with three longitudinal riblets ending in three tips were found on the middle and trailing edges of the first dorsal fin and caudal fin, where water flow states progress from transitional to turbulent. The ranges of the ratio of riblet depth to spacing (RD/RS) in the anterior zone, middle zone and posterior zone of the shark were 0.05–0.17, 0.08–0.23, and 0.32–0.33, respectively. The riblet angle generally followed the flow direction, but it varied across different areas of the body. The turbulence intensity increased gradually across the first dorsal fin, pectoral fin, caudal fin, and the shark body overall. In summary, it was found that the microstructure riblets on the shark skin surface, generally thought to be drag reduction structures, were only located in transitional and turbulent regions at the middle and trailing edge of the shark body and fin surfaces, and there were almost no microstructural grooves in the laminar flow regions along the leading edge. These findings can provide design guidance for engineering applications of bionic riblet surfaces. Riblets placed in transitional and fully turbulent regions can be used to effectively reduce drag. The riblet direction should be consistent with the direction of flow.

Aiming at determining the characteristics of small volume and complex heat and mass transfer of micro-reactors, an online measurement system was designed and built. The temperature of the reactor surface was measured by infrared thermography. For reconstruction of the three-dimensional temperature field of the micro-fixed bed reactor, mathematical and physical models were established by finite difference of governing equations and boundary conditions, and the objective function was established based on the principle of least squares. Then, using the conjugate gradient algorithm, the three-dimensional temperature field was rebuilt in the fixed bed reactor. It was verified that the micro-reactor filled with resin particles had a porosity of 0.432 under an initial temperature of 20 °C and adiabatic conditions; distilled water of a constant temperature of 50 °C was introduced into the reactor at a flow rate of 3.2 ml/min, and the internal temperature field was deduced from the surface temperature of the reactor. The experiment also used micro-thermocouples to measure the internal temperature at multiple points to compare with the inverse temperature field. The temperature change trend was consistent, and the maximum error was 4.85% in a no reaction condition and 7.1% in catalytic reactions, which verified the accuracy of the inverse method.

The adhesion of water to the surfaces of unmanned aerial vehicles (UAVs) adversely affects the function. The proposed UAVs will have underwater as well as flight capability, and these aquatic UAVs must shed water to resume flight. The efficient separation of the adhering water from aquatic-UAV surfaces is a challenging problem; we investigated the application of hydrophobic surfaces as a potential solution. Using aquatic-UAV models, one with hydrophilic surfaces and the other with superhydrophobic anisotropic textured surfaces, the antiwetting mechanism of the hydrophobic surfaces was investigated using a simulated-precipitation system and instrumentation to measure the load of the water adhering to the aquatic UAV, and to measure the impact energies. When the model was stationary (passive antiwetting), no adhesion occurred on the superhydrophobic surfaces, while continuous asymmetric thick liquid films were observed on the hydrophilic surfaces. The superhydrophobic surfaces reduced the rain loading by 87.5%. The vibration and movement of the model (dynamic antiwetting, simulating flight motions) accelerated the separation process and reduced the contact time. The observed results were augmented by the use of computational fluid dynamics with lattice Boltzmann methods (LBM) to analyze the particle traces inside the droplets, the liquid phase velocity-field and pressure-field strengths, and the backward bouncing behavior of the derived droplet group induced by the moving surface. The synergy between the superhydrophobic surfaces and the kinetic energy of the droplets promotes the breakup of drops, which avoids the significant lateral unbalance observed with hydrophilic surfaces during simulated flight.

Variable thermal resistance (VTR) based on the Peltier and Seebeck effects can convert electric power to heat, thus promoting or hindering heat transfer. A method of using VTR is proposed in this project. VTR, a variable thermal boundary condition, is applied in temperature control systems owing to its fast response and high accuracy. An experiment was conducted to demonstrate the feasibility of using VTR in temperature control systems. Then, a thermal model was built using Simulink that can simulate the model under an ideal heat transfer condition. The experimental and simulation data indicate that the accuracy and anti-interference of a temperature control system can be strengthened by using VTR as the thermal boundary condition. The standard deviation of temperature signals decreases when using VTR control with basic on–off temperature control in the system.

Up to now, there's a limited number of studies on the relationship between PINK1/Park2 pathway and mitophagy in NAFLD. To investigate the effect of Park2-mediated mitophagy on nonalcoholic fatty liver disease (NAFLD). Oleic acid was used for the establishment of NAFLD model. Oil red-dyed lipid drops and mitochondrial alternations were observed by transmission electron microscopy. Enzymatic kit was used to test lipid content. The levels of IL-8 and TNF-α were determined by ELISA. Lenti-Park2 and Park2-siRNA were designed to upregulate and downregulate Park2 expression, respectively. The changing expression of PINK and Park2 was detected by RT-qPCR and Western blot. Immunofluorescence staining was applied to measure the amount of LC3. Successful NAFLD modeling was featured by enhanced lipid accumulation, as well as the elevated total cholesterol (TC), triglyceride (TG), TNF-α and IL-8 levels. Mitochondria in NAFLD model were morphologically and functionally damaged. Park2 expression was upregulated by lenti-Park2 and downregulated through Park2-siRNA. The PINK1 expression showed the same trend as Park2 expression. Immunofluorescence staining demonstrated that the when Park2 was overexpressed, more LC3 protein on mitochondrial autophagosome membrane was detected, whereas Park2 knockdown impeded LC3' locating on the membrane. The transmission electron microscopy image exhibited that the extent of damage to the mitochondrial in NAFLD model was revered by enhanced Park2 expression but further exacerbated by reduced Park2 expression. Park2-mediated mitophagy could relive NAFLD and may be a novel therapeutic target for NAFLD treatment. [ABSTRACT FROM AUTHOR]

This study incorporates quantitative color examination and measurement into the study of visual performance of traditional Chinese architecture. It provides an objective and scientific way for generating color-restoration drawings that either reflect the "original" or "current" state of the building by looking for the extreme chroma color and calculating the average color. This method reinforces people's understanding of the true appearance of historic buildings and makes it possible to compare the similarities and differences of color schemes between different cases on an open and standard ground. This paper is supported by the Chinese National Key Research and Development Program of China - Research and Demonstration of Key Technologies for Scientific Cognition and Ontology Protection of Ming and Qing Dynasty Imperial Building Construction Techniques, Project Approval No. 2020YFC1522401. [ABSTRACT FROM AUTHOR]

Purpose ‒ The purpose of this study was to evaluate the association of hearing loss with atherogenic index (AI) in the general population. Methods ‒ A multistage study using cluster random sampling method was conducted in the Zhejiang province from 2016 to 2018. Pure-tone air-conduction hearing thresh-olds were measured at frequencies of 0.125–8 kHz for each subject. After obtaining their consent, all participants were asked to provide their own plasma lipid data. Results ‒ A total of 3,414 eligible participants were included, 1,765 (51.7%) were men and 1,649 (48.3%) were women and 1,113 (32.6%) had hearing loss. Ridge regression showed increased AI in subjects with hearing loss. The subgroup with the highest quartile of AI, presenting the highest risk of hearing loss as compared to the lowest quartile, comprised young and middle-aged women. Further analysis revealed that the AI in people with different categories of hearing loss was higher than that in the normal population, except for those with (extremely) severe hearing loss. Moreover, the young and middle-aged women exhibited the most significant correlations between AI and hearing loss. Conclusion ‒ AI was positively associated with hearing loss in the general population, especially the young and middle-aged women. [ABSTRACT FROM AUTHOR]

A novel calorimetric biosensor is developed by recirculating flow injection analysis. The biosensor consists of a peristaltic pump, two switching valves, a thermostat, an injection valve, two twin cells (a reaction cell and a reference cell), a thermopile, a data acquisition module, and a personal computer (PC). This biosensor with an improved structure can respond to reaction heat timely by placing the thermopile between the reaction and reference cells. Enzymatic reaction will be continuous when an excessive substrate is introduced into the two cells and flows circularly through them. The calorimetric biosensor has been applied successfully in dichlorvos detection by a new test method. In this method, two parameters of constant response in the zero-order reaction phase and the transition moment from zero-order reaction to first-order reaction are obtained from the progress curve of the enzymatic reaction. Under a certain initial enzyme activity derived from the transition moment, dichlorvos can be determined by comparing the difference in constant response caused by the enzymatic reaction with inhibition in the reaction cell and without inhibition in the reference cell. The performance shows a linear range of 0.01–0.5 mg/L with a relative standard deviation (RSD) of 3–10% and a limit of detection (LOD) of 0.01 mg/L, as well as a detection duration of 20 min. The system is fast, can repeatedly and easily be used, and can improve automation and prevent possible input errors. It is suitable for the rapid detection of pesticides in the field. [ABSTRACT FROM AUTHOR]