Mechanism Of Energy Transformation Research Articles

A Review of an Investigation of the Ultrafast Laser Processing of Brittle and Hard Materials.

Ultrafast laser technology has moved from ultrafast to ultra-strong due to the development of chirped pulse amplification technology. Ultrafast laser technology, such as femtosecond lasers and picosecond lasers, has quickly become a flexible tool for processing brittle and hard materials and complex micro-components, which are widely used in and developed for medical, aerospace, semiconductor applications and so on. However, the mechanisms of the interaction between an ultrafast laser and brittle and hard materials are still unclear. Meanwhile, the ultrafast laser processing of these materials is still a challenge. Additionally, highly efficient and high-precision manufacturing using ultrafast lasers needs to be developed. This review is focused on the common challenges and current status of the ultrafast laser processing of brittle and hard materials, such as nickel-based superalloys, thermal barrier ceramics, diamond, silicon dioxide, and silicon carbide composites. Firstly, different materials are distinguished according to their bandgap width, thermal conductivity and other characteristics in order to reveal the absorption mechanism of the laser energy during the ultrafast laser processing of brittle and hard materials. Secondly, the mechanism of laser energy transfer and transformation is investigated by analyzing the interaction between the photons and the electrons and ions in laser-induced plasma, as well as the interaction with the continuum of the materials. Thirdly, the relationship between key parameters and ultrafast laser processing quality is discussed. Finally, the methods for achieving highly efficient and high-precision manufacturing of complex three-dimensional micro-components are explored in detail.

Does energy transformation improve green development efficiency? Evidence from Sichuan Province, China

Green sustainable development has become an important topic of concern to human society.Energy clean and low-carbon transformation is an important lever for promoting regional green development. Investigating the driving mechanisms of energy transformation is helpful to explore the effective path for accelerating the process of green development. Meanwhile, Sichuan Province is a demonstration province of clean energy and an important energy transportation hub in China, and it should play an exemplary role in the process of high-quality development. In this regard, this study uses the two-stage super-efficiency network SBM model to measure the green development efficiency based on the dual perspectives of green production and environmental governance. Based on historical data from 2006 to 2022, Technological innovation, industrial structure, and foreign direct investment are selected as transmission variables, and the fixed effects regression model is used to empirically analyse the direct and indirect impact effects of ET on GDE. The results show that the green development efficiency in Sichuan Province has gradually increased from 0.8303 in 2006–0.9270 in 2022, which is at a relatively high level. Energy transformation is helpful to improve the green development efficiency in Sichuan Province. However, due to insufficient complementary power sources and challenges in balancing energy supply and demand, the incentive level needs to be strengthened. Technological innovation, industrial structure, and foreign direct investment show indirect heterogeneous transmission effects in the process of influence.

Understanding energy transformation mechanism of rockbursts through experimental and theoretical methods

Understanding the energy transformation mechanism in rockbursts is essential for predicting and mitigating potentially catastrophic rock failures. In this study, Double Springs Release Tests (DSRTs) were proposed in a laboratory setting to investigate the energy transformation of rockbursts from inception to development. High-speed cameras and image processing algorithms were utilized to calculate different types of energy throughout the duration of the burst. Theoretical analyses, grounded in structural dynamics and stress wave equations, was conducted and cross-referenced with the experimental results. The study found that wave impedance ρE is a key indicator of burst intensity. The research demonstrated that the impact energy in DSRTs originates from both the impact medium and the surrounding medium, and explored how these two components contribute to the total impact energy of the impact medium.

Nd-doped CsPbBr3 borosilicate glass ceramics: Crystallization behavior and photoluminescence kinetics

Rare-earth (RE) doping is one of the valid approaches to optimize the optical performance of the CsPbBr3 perovskite quantum dot glass. Thus, the research on the crystallization behavior of RE ions doped CsPbBr3 borosilicate glass and the energy transformation mechanism between the RE ions and CsPbBr3 is significant for the development of advanced Ln-doped perovskite glass materials. In this work, CsPbBr3 borosilicate glass ceramics doped with different concentrations of Nd2O3 were successfully synthesized. It was found that Nd2O3 makes the glass network structure more compact and then inhibits the precipitation of CsPbBr3 nanocrystals. Additionally, there is energy transfer between Nd3+ and CsPbBr3, which quenches the photoluminescence of CsPbBr3 borosilicate glass. This work deepens the understanding of the structural and photophysical properties of Ln-doped CsPbBr3 borosilicate glass ceramics and provides a reference value for the related work of RE ions doped perovskite borosilicate glass.

NUMERICAL METHOD FOR ASSESSING EFFICIENCY OF WAVE ENERGY CONVERTOR INTEGRATED INTO COASTAL PROTECTION STRUCTURES

The use of wave energy by converting it into electricity depends on the efficiency of wave energy converters, which are negatively affected by marine factors. Many design flaws can be eliminated at the stage of design and testing of devices by using its numerical models based on the application of the hydrodynamic theory of propagation and interaction of waves with marine structures. The use of the modern computational methods of hydrodynamics to determine the influence of some design factors of wave energy converters incorporated into a submerged breakwater is considered in the paper. The results of numerical studies showed that if a submerged breakwater is located in the wave stream and with a transducer installed on its crest, there is a change in flow velocities and pressure in the transducer chamber, which affects the efficiency of energy extraction. Additional advantages arise as a result of the introduction of a complex structure with coastal protection and power supply functions. The obtained calculation results visualize the qualitative indicator of the influence of the design factors of the converter. Additional conclusions can be obtained by processing the numerical results. As a result of numerical experiments conducted with using REEF3D CFD computer system, the measures for selecting the parameters of the converters were proposed based on mathematical modeling of specific structures. The research related to the determination of the mechanisms of wave energy transformation when interacting with coastal protection elements focused on increasing the efficiency of the convertor by locating in deeper water, which includes detailed testing, investigations and improvement of various types of constructions, is carried out on the computing and laboratory base of Institute of Hydromechanics.

Mechanism of the glucono-δ-lactone induced soymilk gelation: Enthalpy and entropy transformation in the cross-linking of protein molecules

This study aimed to explore new techniques to regulate the quality of soy products. The glucono-δ-lactone (GDL) induced soymilk gelation process and the gel network structure characteristic were compared as a matter of temperature, and the role of reaction kinetics was discussed. Results showed that there were similarities in the development of Gʹ curves under different temperatures, whereas the gel network structures and the energy requirements of cross-linking reactions were different. In the high-temperature region (70 °C–95 °C), the exposure and binding of reactive groups were promoted. The activation enthalpy (ΔH*) required by protein aggregates decreased and the effect of entropy reduction (−TΔS*) was enhanced, which led to shorten the preaggregation time (tg) and increase the gelation rate (k), resulting in the formation of rough, porous gel network with high stiffness. By contrast, in the low-temperature region (40 °C–70 °C), high enthalpy contributions and low entropy changes were required, then a fine, soft, and tender gel network formed. Besides, a funnel-shaped model of the enthalpy–entropy energy transformation mechanism of soymilk gelation was proposed. The results of this study revealed that adjusting the enthalpy–entropy energy requirements of the protein cross-linking reaction could be utilized to the regulation of the network structure and quality of soymilk gels, which could enrich the reaction kinetics theory and provide innovative ideas for food quality control technology from the perspective of energy requirement and energy input.

Thermodynamic Behavior and Energy Transformation Mechanism of the Multi-Period Evolution of Cavitation Bubbles Collapsing near a Rigid Wall: A Numerical Study

The dynamic behavior and energy transformation mechanism of the multi-period evolution of bubbles collapsing near a wall have been essential considerations in bubble dynamics research. In this study, a compressible two-phase solver considering thermodynamics and phase transitions is developed on OpenFOAM (version v2112). This model is validated via comparison with analytical solutions and experimental results. The dynamics of the multi-period evolution of bubbles collapse process at different dimensionless stand-off distances (γ) were accurately reproduced. The results indicate that the shock wave emitted by the collapse of cavitation bubbles impacts the wall, causing the fluid temperature along the wall to increase. Moreover, the liquid jet has a dual effect on the wall temperature increase, depending on the initial stand-off distance between the bubble and the wall. When γ is small, the jet carries the low-temperature fluid to occupy the high-temperature region, and when γ is large, the jet carries the high-temperature fluid to occupy the low-temperature region. Compared with the mechanisms above of wall temperature increase, the collapse process of cavitation, when directly attached to the wall, increases the fluid temperature along the wall more significantly. Additionally, an energy transformation mechanism is proposed considering the internal bubble energy based on the analysis of the internal bubble energy and acoustic radiation energy with different γ values. Both the internal and acoustic radiation energy initially decreased and subsequently increased with increasing γ values. These findings provide deeper insights into the near-wall collapsing cavitation process mechanism.

Energy Action Mechanism of Reinforced Sandstone under Triaxial Cyclic Loading and Unloading

In underground engineering, reinforcement is a necessary means to ensure the stability of surrounding rock. Due to the stress redistribution caused by excavation disturbances, the reinforced rock mass is frequently subjected to loading and unloading, and its mechanical properties change accordingly. Based on the above engineering practice, using pasted circular CFRP, an approximate simulation of the rock reinforcement effect of bolt and shotcrete support was performed. Triaxial cyclic loading and unloading tests of reinforced sandstone were carried out, and the influence of different reinforcement schemes on the mechanical properties was compared and analyzed. Furthermore, the strengthening mechanism, damage evolution, and energy transformation mechanism of CFRP are discussed. The results showed that the peak strength increased about 14.2% and 23.8% with the two reinforced schemes, and the residual strength increased about 27.3% and 52.8% with the increase in the area reinforced by CFRP. Under the same confining pressure and strain conditions, the characteristic energy density and elastic energy ratio increased with an increase in the reinforcement area, but the damage variable decreased. It is proved that CFRP can improve energy absorption efficiency, enhance the energy storage limit, and reduce dissipation efficiency. By inhibiting the propagation of internal fissures and limiting the energy dissipation during fractures, the rock mass can be restrained and strengthened.

Study on Strategic Interaction between Government and Farmers in Rural Passive Energy Transformation.

In the implementation of public environmental policies, the deviation between the behavioral intention of farmers and the results of policy implementation is widespread. To reveal the universality, and break through existing research perspectives, this paper, starting from the interaction between the government and farmers, builds a rural passive energy transformation mechanism conceptual model. Using the policy of "coal to gas" in northern China area as a case, a comprehensive analysis of the influencing factors of peasant household behavior response is presented, using a structural equation to compute the interaction strength between the two agents. The results of the study show that: (1) the standardized path coefficients of household behavioral intention and government policy characteristics on household behavioral response are 0.458 and 0.554, respectively. The effect of government is stronger than that of households, which highlights the change effect of government on household behavioral responses and explains the reason for the deviation between behavioral intention and behavioral response; and (2) The standardized correlation coefficient between government policy characteristics and farmers' behavioral intention is 0.858, indicating that the interaction between government and farmers has a significant impact on policy results, and verifies the important role of research on the interactions between government and farmers. Therefore, in order to improve the effect of rural energy transformation, it is necessary to strengthen the interactions between the government and farmers, to smooth the channels of farmers' demands, and to form a pattern of air pollution control with government guidance and full participation.

An open call for contributions to a special issue of Biophysical Reviews highlighting the research themes of VII Congress of Russian Biophysicists 2023.

We announce a call for contributions to a Special Issue of Biophysical Reviews associated with the VII Congress of Russian Biophysicists (to be held in Krasnodar, Russia, 17-23 April 2023). The Congress is the main biophysical meeting held within Russia and is organized every four years. The Congress will focus on both the physical principles and mechanisms of biological processes occurring at different levels of structural organization, from molecular to cellular to organism and to population levels. The Special Issue will accept reviews on topics from molecular biophysics, structure and dynamics of biopolymers, biophysics of the cell, energy transformation mechanisms, biophotonics, ecological biophysics, and medical biophysics, following the sections of the Congress. The VII Congress of Russian Biophysicists is supported by International Union of Pure and Applied Biophysics (IUPAB). Here we describe main topics and sections of the coming event, the paper types for the journal issue, and the key deadline dates.

A novel solar-driven water and electricity cogeneration integrated system by multistage vaporization enthalpy recycling

Satisfied the long-term demand for electricity and freshwater shortage in off grid and resource constrained areas through clean energy is particularly important in the context of comprehensive clean and green development. In this paper, a novel solar-driven freshwater-electricity cogeneration system was proposed, which has high efficiency solar-thermal-electrical conversion capability and outstanding thermal management performance. First, a solar-thermal-electrical coupling numerical model of the system was established, the energy transmission and transformation mechanism were analyzed, and the structural parameters such as the air gap and distillation stages were optimized to further improve the performance of the system. Second, guided by theoretical modeling, the outdoor experiment verified the outstanding thermal management performance through evaporative cooling of seawater and the efficient solar-electricity-steam conversion ability of the system. A photovoltaic module temperature was reduced to about 8 °C, as compared to the same photovoltaic module working alone. And the reduced photovoltaic module temperature led to a 0.86 % increase in average solar-electricity conversion efficiency. Meanwhile, a large amount of freshwater was obtained by consuming the waste heat of photovoltaic modules. The average water production rate was about 2.06 kg·m−2·h−1 under the real outdoor environment. Finally, the system has a stable self-cleaning ability without solid salt crystallization and efficient seawater desalination performance in freshwater production. Hence, this novel system not only realizes passive high energy transfer efficiency to produce freshwater and electricity, but also provides a strategy to solve the crisis of energy and water resources in the future.

Energy transduction and the mind–mitochondria connection

The body and mind are fuelled by energy. But where does the energy come from? The sun beams energy through space as photons that are captured by plants, which store that energy in the improbable separation of carbon and oxygen. By reuniting carbon and oxygen in their mitochondria, breathing animals power their warm bodies, thoughts, feelings, minds and consciousness. Thus, the life-giving flow of energy proceeds from light, through chemistry, into life. Mapping the mechanisms of energy transformation among mind-imbued organisms is the challenge for the field of mitochondrial psychobiology. Emerging evidence positions energy as the substrate of the mind–body connection, linking the molecular processes in the organism and the subjective experiences in our mind. Building a bioenergetic psychobiology framework can stimulate the health sciences in three main ways: it provides an empirical foundation to examine the interconnectedness of people and their environment, highlights health as a dynamic process, and may eventually illuminate new approaches and strategies to optimize the energetic mind–body crosstalk that is the basis of human health.

Mechanism of Energy Storage and Transformation in the Mitochondria at the Water-Membrane Interface.

In this review, we discuss the mechanisms of generation of membrane-bound protons using different energy sources in model and natural systems. Analysis of these mechanisms revealed that all three types of reactions include the same principal stage, which is dissociation of electrically neutral Brønsted acids at the interface during transition from the hydrophobic phase to water with a low dielectric constant. Special attention is paid to the fact that in one of the analyzed model systems, membrane-bound protons provide energy for the reaction of ATP synthesis. Similar mechanism for the generation of membrane-bound protons has been found in natural membranes involved in oxidative phosphorylation, in particular, on the membranes of mitoplasts and mitochondria. The energy of oxidative reactions required for ATP synthesis, is stored at the intermediate stage not only in the form of transmembrane electrochemical potential of protons, but also and perhaps mostly, as protons attached to the inner mitochondrial membrane. The process of energy storage in mitochondria is linked to the transfer of protons that simultaneously perform two functions. Protons on the membrane surface carry free energy and, at the same time, act as substrates facilitating the movement of F1F0-ATP-synthase biological machine.

MITODYN: An Open Source Software for Quantitative Modeling of Mitochondrial and Cellular Energy Metabolic Flux Dynamics in Health and Disease.

Mitochondrial respiratory chain (RC) transforms the reductive power of NADH or FADH2 oxidation into a proton gradient between the matrix and cytosolic sides of the inner mitochondrial membrane, that ATP synthase uses to generate ATP. This process constitutes a bridge between carbohydrates' central metabolism and ATP-consuming cellular functions. Moreover, the RC is responsible for a large part of reactive oxygen species (ROS) generation that play signaling and oxidizing roles in cells. Mathematical methods and computational analysis are required to understand and predict the possible behavior of this metabolic system. Here we propose a software tool that helps to analyze individual steps of respiratory electron transport in their dynamics, thus deepening understanding of the mechanism of energy transformation and ROS generation in the RC. This software's core is a kinetic model of the RC represented by a system of ordinary differential equations (ODEs). This model enables the analysis of complex dynamic behavior of the RC, including multistationarity and oscillations. The proposed RC modeling method can be applied to study respiration and ROS generation in various organisms and naturally extended to explore carbohydrates' metabolism and linked metabolic processes.

On the Frequency Drift of Coronal Loop’s Fast Kink Oscillation: Effects of Quasi-static Evolution in Loop Density

Abstract Although the fast kink oscillation, as one of a few fundamental modes in coronal seismology, has received a lot of attention over the past two decades, observations of its frequency drift remain elusive. There is evidence that this phenomenon is related to the quasi-static evolution of loop density. We therefore consider analytically the effects of a quasi-static density evolution on the fast kink oscillation of coronal loops. From the analyses, we determine explicitly the analytic dependence of the oscillation period/frequency and amplitude on the evolving density of the oscillatory loop. The findings can well reconcile several key characters in some frequency drift observations, which are not understood. Models of fast kink oscillation in the thermal dynamic loop are also established to investigate the present effects in more detail. Our findings not only show us a possible explanation for the frequency drift of the coronal loop’s fast kink oscillation, but also a full new energy transformation mechanism where the internal energy and the kinetic energy of an oscillating coronal loop can be interchanged directly by the interaction of the loop’s oscillation and its density evolution, which we suggest may provide a new clue for the energy processes associated with a thermodynamic resonator in the space magnetic plasma.

ENERGY TRANSFORMATION MECHANISM OF A GAS BUBBLE COLLAPSE IN THE FREE-FIELD1)

Both the experiment method and numerical simulation method are applied in this paper to investigate the energy transformation mechanism of a gas bubble collapseing in the free field. The bubble radius, velocity and acceleration of the bubble evolution process are obtained according to the experimental results via the schlieren method. These parameters are substituted~into the bubble potential energy and kinetic energy equation to explain the energy changing. By using the CFD simulation method, a three-dimensional model with reformulated mass conservation equation and momentum equation considering the weakly compressibility, is introduced to discuss the bubble collapse process. The pressure and velocity distribution around the bubble are extracted from the simulation results in order to analyze the energy transformation mechanism. The results show that (i) the relation between the potential energy and bubble radius maintains the positive correlation, with the increasing of the potential energy, the kinetic energy decreases significantly. The value of potential energy is maximum at the end of the bubble expanding, and the kinetic energy of free field returns to zero at the same time. (ii) During the shrinking stage, a high-pressure area appears around the bubble, and gradients of velocity and pressure are higher than the other area in the free field. The high-pressure area is shrinking gradually when the bubble is collapsing. (iii) The potential energy transforms into kinetic energy during the whole process of the bubble evolution, and the kinetic energy is form of wave energy. A shock wave is captured when the bubble collapse, and the most of bubble energy transform into wave energy of the shock wave at this time.

Experimental Investigation on Deformation and Strength Behavior of Marble with the Complex Loading-Unloading Stress Path

The excavation of deep tunnel in rock mass undergoes complex loading and unloading stress paths, resulting in rib spalling, flaking, and even severe rockburst disasters. Based on the variation law of the stress path of the surrounding rock, laboratory tests of rock mechanics are designed, and the deformation and strength behavior of marble with different initial confining pressure and unloading rates are systematically studied. By introducing strain increment, the characteristic stress, and the dilatancy index, the rock’s dilatancy and brittleness under different unloading conditions are quantitatively analyzed. During unloading, the energy transformation mechanism of rock is described, and the law of deformation and failure is discussed based on characteristic energy. The rock failure strength fitting formula is given by applying the Mogi–Coulomb criterion and elastic strain energy criterion. The advantages of the elastic strain energy criterion are theoretically explained. This study shows that comprehensive consideration of the complex stress paths, confining pressure levels, and the loading-unloading rates of surrounding rock is an effective way to accurately study unloading rock characteristics. The results can provide theoretical basis for stability analysis of high-stress underground engineering.

Development of a Model to Predict Vibrations Induced by Blasting Excavation of Deep Rock Masses under High In Situ Stress

During the process of blasting excavation of deep rock masses under high in situ stress, energy produced by the explosive and the strain energy released by rock mass excavation constitute the energy source of vibration. However, in traditional Sadov’s empirical formula, the energy produced by explosive explosion is only considered which makes the error higher when it is used to predict the blasting-induced vibration peak under the condition of high in situ stress. In this study, energy transformation and distribution mechanisms caused by excavation of deep rock masses were analyzed at first. Then, a prediction model of vibration peak based on the principle of energy balance was established by dimension analysis. Finally, the proposed model was trained and tested with the vibration data monitored during the blasting excavation of deep buried tunnel in Jinping II hydropower station. The result shows that compared with the traditional prediction model, the proposed model has higher fitting correlation coefficient and lower root-mean-square error, which can be better applied to the prediction of vibration induced by blasting excavation of deep rock masses under high in situ stress.

Flow energy transformation and dissipation mechanisms of carbon dioxide, nitrogen, and water jets

Supercritical carbon dioxide (SC–CO2) shows many advantages in the exploitation of shale gas and geothermal energy. This condition is mainly because pressure synergizes with temperature in rock-breaking. A computational model was established on the basis of an experimental setup and validated with experimental data to study the energy transformation and dissipation mechanism. The jet fields of water, SC-CO2 and nitrogen were studied. Result shows that the jet center pressure and temperature difference are in the following descending order: SC-CO2 > nitrogen > water, indicating that SC-CO2 jet can produce the maximum broken volume. The SC-CO2 and nitrogen temperature drops are induced by endothermic expansion, and the water temperature increment is caused by viscous heating. The total pressure underestimates the energy of SC-CO2 and nitrogen flows, which is harmful to safety risk control. The dissipation rate of flow energy is in the following ascending order: SC-CO2 < nitrogen < water. This condition is because less large eddy energy transfer is produced in SC-CO2 and nitrogen jets than water jet, and shock wave leads to more energy loss of nitrogen than SC-CO2. The temperature drop in jets shows that SC-CO2 and nitrogen have the potential for enhanced heat transfer. The findings provide a deeper understanding of efficient control and the use of SC-CO2 flow energy.

Cryo-EM structures of the air-oxidized and dithionite-reduced photosynthetic alternative complex III from Roseiflexus castenholzii.

Alternative complex III (ACIII) is a multisubunit quinol:electron acceptor oxidoreductase that couples quinol oxidation with transmembrane proton translocation in both the respiratory and photosynthetic electron transport chains of bacteria. The coupling mechanism, however, is poorly understood. Here, we report the cryo-EM structures of air-oxidized and dithionite-reduced ACIII from the photosynthetic bacterium Roseiflexus castenholzii at 3.3- and 3.5-Å resolution, respectively. We identified a menaquinol binding pocket and an electron transfer wire comprising six hemes and four iron-sulfur clusters that is capable of transferring electrons to periplasmic acceptors. We detected a proton translocation passage in which three strictly conserved, mid-passage residues are likely essential for coupling the redox-driven proton translocation across the membrane. These results allow us to propose a previously unrecognized coupling mechanism that links the respiratory and photosynthetic functions of ACIII. This study provides a structural basis for further investigation of the energy transformation mechanisms in bacterial photosynthesis and respiration.