Propagation Speed Research Articles

Characteristics of Precipitation and Mesoscale Convective Systems Over the Peruvian Central Andes in Multi 5‐Year Convection‐Permitting Simulations

AbstractUsing the Weather Research and Forecasting model with two planetary boundary layer schemes, ACM2 and MYNN, convection‐permitting model (CPM) regional climate simulations were conducted for a 6‐year period, including a one‐year spin‐up period, at a 15‐km grid spacing covering entire South America and a nested convection‐permitting 3‐km grid spacing covering the Peruvian central Andes region. These two CPM simulations along with a 4‐km simulation covering South America produced by National Center for Atmospheric Research (NCAR), three gridded precipitation products, and rain gauge data in Peru and Brazil, are used to document the characteristics of precipitation and mesoscale convective systems (MCSs) in the Peruvian central Andes region. Results show that all km‐scale simulations generally capture the spatiotemporal patterns of precipitation and MCSs at both seasonal and diurnal scales, although biases exist in aspects such as precipitation intensity and MCS frequency, size, propagation speed, and associated precipitation intensity. The 3‐km simulation using MYNN scheme generally outperforms the other simulations in capturing seasonal and diurnal precipitation over the mountain, while both it and the 4‐km simulation demonstrate superior performance in the western Amazon Basin, based on the comparison to the gridded precipitation products and gauge data. Dynamic factors, primarily low‐level jet and terrain‐induced uplift, are the key drivers for precipitation and MCS genesis along the east slope of the Andes, while thermodynamic factors control the precipitation and MCS activity in the western Amazon Basin and over elevated mountainous regions. The study suggests model improvements and better model configurations for future regional climate projections.

Investigating the explosive characteristics of hydrogen/ n-butane blended fuel: Experimental and kinetic insights

Investigating the explosive characteristics of H2/n-C4H10 mixtures is crucial for the safe utilization of this blended fuel. Our study focused on varying equivalent ratios and hydrogen blending ratios within a closed 20-L spherical explosion vessel. Additionally, the microscopic kinetics of the reactions were analyzed through chemical reaction simulation. Our findings indicate that the most violent explosion occurred at an equivalent ratio of 1.2. Increasing hydrogen content intensified combustion reactions, reducing flame thickness and inducing cellular structures along the flame front. This escalation also increased explosion pressure, flame temperature, and flame propagation speed, elevating explosion risk. Moreover, the equilibrium molar fraction of O2 and CO2 decreased while that of H2O increased with higher hydrogen blending ratios. Correspondingly, the heat release rate and generation rates of H•, O•, and OH• radicals increased. Notably, the peak time of C2H4 and CH4 consumption rates preceded. Additionally, R5: O2 + H• = O• + OH• and R978: C4H10 + H• = SC4H9 + H2 represented crucial promoting and inhibiting steps, respectively. These insights deepen our understanding of the explosion mechanism of H2/n-C4H10 mixtures, providing a theoretical basis for designing safer protective measures and evaluating explosion risks in industrial production.

VELOCITY AND EVOLUTION OF SHOCK WAVES IN SAND WITH INCREASING WATER CONTENT

Interest in the problems of shock wave propagation in saturated porous media is associated with studying seismic exploration issues, modeling the hummer effect during hydraulic fracturing, studying the water-gas impact on formations for the purpose of efficient oil production, etc. Experimental work on waves in bulk media is usually carried out in shock tubes. Traditionally, shock tubes are used to study the characteristics of the propagation of shock waves in various media, to analyze the wave properties of these media based on the speed of the shock waves and the change in the shape of the pulse along the passage of the first – main pulse. In a shock tube equipped with a section of bulk media, the wave is repeatedly reflected from the surface of the porous medium under study and the upper end of the tube. Re-reflected waves can be used to study changes in the environment that occurred under the influence of a shock wave, i.e. as probing pulses. In this article, sounding is understood as identifying acoustic properties (changing the shape of shock pulse diagrams and their velocities). This paper presents the results of experimental studies of the propagation of shock waves of small amplitude in sand with a volumetric content of liquid in the pore space from 0 to 40 %, and illustrates the influence of the presence of liquid in the pores on the shape of the main and probing pulses. The research was carried out using the Shock Tube installation, in the Laboratory of Experimental Hydrodynamics of the Mavlyutov Institute of Mechanics of Ufa Branch RAS. An increase in the speed of wave propagation was established with increasing water saturation of sand in the range from 0 to 40 %. An increase in the amplitude of reflected waves when passing through sand, the formation of peaks and stretching of pulses were discovered. The research results can be used in processing geophysical data to interpret seismograms of sandy deposits saturated with gas-liquid systems.

The economophysical model of the propagation of innovation: the Ising model

The process of technical and economic justification of investment, analysis and evaluation of the effectiveness of innovation requires a tool for describing and modeling the process of distribution of technology in the industry. The work presents a model of propagation of innovation involving physical approaches, describing the market saturation point, i.e. the point at which the exponential growth of the innovation propagation speed is replaced by the logarithmic growth. The object of the study is the propagation of innovation, and the subject is the development of the market saturation point functional. The authors justified the implementation and described the approach to modeling of the process of saturation of the market with innovation by the physical Ising model. The value of the Ising model’s toolkit is presented by the Curie point in ferromagnets which characterizes the second order phase transition. The article presents the mathematical model of the compliance of physical parameters with economic ones: the amount of inter-company influence, barriers to implementation and breakthrough of innovation. The authors adduce the discussion of the limitations and applicability of this model as well as further potential directions of study of economophysical models. The tools developed by the authors can be used in all sectors of economics to improve their innovation activity level.

Responses of summer mesoscale convective systems to irrigation over the North China Plain based on convection-permitting model simulations

Extensive irrigation activities in the North China Plain (NCP) significantly influence regional weather and climate. However, previous studies focusing on the NCP were primarily based on coarse-resolution models, which are unable to explicitly resolve convection systems, causing large uncertainty in precipitation simulations. In this study, a convection-permitting model coupled with a dynamic irrigation scheme is utilized to investigate the impacts of irrigation on summertime mesoscale convective systems (MCSs) over the NCP. Sensitivity experiments with irrigation off and on are conducted for 5 summers and an MCS identification and tracking algorithm is applied to both satellite observations and model simulations. We find that incorporating irrigation in the model increases MCS precipitation, which agrees more with observations. The probability distributions of MCS lifetime, area, propagation speed, and intensity are all better simulated with irrigation. Irrigation increases the occurrence frequency of MCSs throughout the entire day. The nighttime increase is partly because of more frequent local initiation of MCS developed from isolated deep convection, while the daytime increase is mainly attributed to the changes in MCSs initiating elsewhere and then propagating to the NCP. On average, irrigation induces additional moisture that is more thermodynamically favorable for precipitation, but this effect is partially offset by the weakened ascending air motion primarily caused by irrigation surface cooling. Compared to weak MCS precipitation events, strong MCS precipitation events experience greater enhancement in precipitation intensity when including irrigation because the offset effect from the change in large-scale ascending air motion is insignificant. In addition, irrigation makes the variation of MCS precipitation intensity more correlated with the variation in ascending motion but less correlated with that in atmospheric moisture. Our results suggest the pronounced impacts of irrigation on MCSs over the NCP which should be included in numerical models to improve regional precipitation simulation and prediction.

Numerical simulation of dynamics behavior of pre-ionized pulsed-DC helium plasma jets at atmospheric pressure

A two-dimensional axisymmetric fluid model was established to investigate the dynamic behavior of pre-ionized pulsed-direct-current helium plasma jets at atmospheric pressure. Our simulation results show that, at a relatively low pre-ionization level, the electron number density is reduced and the streamer propagation is decelerated before the plasma jet is ejected from the tube, which is attributed to the inhibitory effect of a recombination process between the positive ions in the streamer and the seed electrons near the anode. As the pre-ionization reaches a relatively high level, the electron number density is larger than that without pre-ionization before the plasma jet is ejected from the tube, which originates from the promotion effect of decreased breakdown voltage. These two competing mechanisms jointly dominate the dynamic behavior of gas discharge in the presence of pre-ionization. After the plasma jet is ejected from the tube, the enhanced discharge power is responsible for the strengthened electric field in the streamer head, augmented total ionization rate, accelerated streamer propagation, and increased number density of electrons and active species, whatever the pre-ionization density is. With the increase in pre-ionization density, the plasma jet length, streamer propagation speed, discharge power, and discharge energy exhibit the initial increase and subsequent decrease variation trend. The optimal enhancement effect is obtained at the pre-ionization density of 6 × 1012 m−3, with the plasma jet lengthened by 28.4% and the energy deposition efficiency enhanced by 28.1%.

The Hydrogen Vehicle in the Context of the Sustainable Development of the Green Road Transport System

Abstract The scientific work presents concrete research carried out by the authors to implement some concepts of technical and managerial nature, so that those interested in this field can get acquainted with a certain way of exposing the problems concerning the hydrogen-powered vehicle, in the context of the sustainable development of the ecological road transport system. At the moment, the car whose energy for propulsion is generated by means of hydrogen or hydrogen fuel cells does not enjoy a high popularity among users, due to the very high purchase price (where we have high technology, we also have a price to match - a fuel cell is more expensive than an electric battery), the reluctance of the population to use this type of fuel, defined by the danger of explosions and fires generated by hydrogen, and the lack of hydrogen refueling stations in Romania and in some European countries. The use of alternative fuels in internal combustion piston engines has the advantage of significantly reducing pollution due to combustion products. With regard to the direct use of hydrogen as a fuel in internal combustion piston engines, we can say that it has proved its inefficiency, because the hydrogen injected or sucked directly into the engine cylinders is unstable, produces uncontrolled burns and detonations, and in the liquid state it is very difficult to store, it requires special transport methods, hydrogen tanks must be armored with Kevlar because hydrogen in the event of a car accident can explode. For example, if we use it as a fuel in a diesel engine, hydrogen may not ignite itself because the self-ignition temperature in the cylinders of compression-ignition engines is high (600°C). However, at a normal stoichiometric ratio, hydrogen has a high flame rate, much higher than gasoline. This creates a thermodynamic cycle of the thermal engine almost perfectly, but ideally, let us not forget that in poor mixtures of air-hydrogen the flame propagation speed is considerably reduced. The compression ratio of the engine is of utmost importance because it is finally defining the thermal efficiency of the engine. In the following, we present a technical and managerial study with engineering nuances, through which readers can look and understand the stage of development, place and role of the vehicle propelled by hydrogen fuel cells. Finally, the conclusions and further directions of research and development in the field addressed are presented.

A new experimental method to study the flame inhibition performance of low concentration halogenated gas

The minimum fire extinguishing concentration is a key index for the development of next generation chemical clean fire extinguishing gases, which is usually got by the cup-burner. The fire suppression performance of low concentration of chemical gas is hard to be understood by the available methods. In this work, the fundamental acknowledgement of steady flame surface attacking mechanism by halon functional group is newly discussed by conducting a series of bench scale tests with a cylindrical channel under a varied fluorinated gases. The characteristics of flame propagation under differentiated air atmosphere environmental conditions is obtained. The influence of fluorine-containing gas flow rate on flame propagation speed is clarified. A dimensionless relationship including atomic radius, bond length, polarization degree, molar mass and molar volume are proposed to describe the influence of low concentration of fluorine-containing gas on flame propagation speed. It provides an insight for the understanding of the flame inhibition performance of low concentration halogenated gas.

Application of optical fiber distributed acoustic sensing system in ultrasonic detection

Abstract The optical fiber distributed acoustic sensing system can continuously detect acoustic signals along the optical fiber, with the characteristics of wide response frequency band, large capacity, anti-electromagnetic interference and so on. An ultra-sensitive distributed optical fiber acoustic sensing system (uDAS) was produced with a high response frequency up to 100 kHz and thousands of sensing points. The arrayed ultrasonic detection can be realized by the distributed characteristics of the system. For verifying its ultrasonic detection ability, it is applied to ultrasonic nondestructive testing of structural defects. 20 optical fiber ultrasonic detection units were constructed. Each one is a fiber ring with a diameter of about 1.5 cm and a length of 2 meters. Two cubic cement structures with a side length of 30 cm were manufactured for experiment, one of which had an artificial internal defect. The optical fiber array was attached to the surface of the cement structure, and the ultrasonic signal with a frequency of 40 kHz was excited at a single point on the opposite side. The ultrasonic propagation speed changes on account of the defects such as holes and loose texture in the propagation path. The defects in the structure are identified and located by analyzing the difference of arrival time of waves. It is expected that such sensing system could found important applications in structure defect detection.

Analysis of the Double Head Streamer Discharge Simulation under Different Pressures

In this research, the dynamics of double-head streamer discharge initiation, propagation, interaction and breakdown in the air under different pressure values were presented. The double-head streamer discharge dynamics were analysed within a plane-to-plane electrode configuration. That was done through many aspects proposed, such as electron density, electric field, space charge density and streamer propagation speed. The simulation performed using ‘COMSOL Multiphysics’ is based on the finite element method and was carried out with the fluid model. The fluid model describes the movement of particle concentrations using partial differential equations (PDEs) together with Poisson’s equation; Poisson's equation and charge concentrations determine the electric field distribution in space. According to the results, as the pressure increased from (1, 2 and 3atm), the evolution time of the streamer increased from (0.563 to16.29ns) with the same breakdown voltage of 19kV. This means that the double-head streamer discharge developed faster with the decrease in pressure.

Impact of plate-deflected flame on thermal runaway propagation of lithium-ion battery

Ceiling jet fire is a common phenomena in thermal runaway (TR) accidents of electric vehicle and energy storage power station scenarios based on lithium-ion battery, which is a potential risk of inducing large-scale fire spread in battery modules, but it is not been known clearly. This work investigates the influence of ceiling jet fire on TR propagation of lithium nickel cobalt manganese oxide (NCM) battery module by arranging a ceiling-like obstacle directly above the tested module. A series of overheat-induced TR propagation tests under different height (H) of ceiling-like obstacle are conducted to gain better understanding of the heat transfer mechanism. The heat transfer and average heating power of ceiling jet fire to adjacent cells are determined for the first time. Results indicate the TR propagation speed of the module accelerates with the decrease of H, and the TR propagation speed inside the cell is not affected by ceiling jet fire. More importantly, the heat transferred from cell experiencing TR to adjacent cells through ceiling jet fire (Qfl) decreases from 11087.33 J to 7872.02 J, and the ratio of Qfl to the total heat released in TR (ΔEtot) declines from 4.02 % to 2.85 % as H increases from 5 to 15 cm. Finally, the change process of contact thermal resistance between adjacent cells and its relationship with heating power are revealed during TR propagation. This work provides a basic understanding of the influence mechanism of ceiling jet fire on TR propagation, which possess important guidance for the safety protection of lithium-ion battery system.

Propagation of sharp wave-ripple activity in the mouse hippocampal CA3 subfield in vitro.

Sharp wave-ripple complexes (SPW-Rs) are spontaneous oscillatory events that characterize hippocampal activity during resting periods and slow-wave sleep. SPW-Rs are related to memory consolidation - the process during which newly acquired memories are transformed into long-lasting memory traces. To test the involvement of SPW-Rs in this process, it is crucial to understand how SPW-Rs originate and propagate throughout the hippocampus. SPW-Rs can originate in CA3, and they typically spread from CA3 to CA1, but little is known about their formation within CA3. To investigate the generation and propagation of SPW-Rs in CA3, we recorded from mouse hippocampal slices using multi-electrode arrays and patch-clamp electrodes. We characterized extracellular and intracellular correlates of SPW-Rs and quantified their propagation along the pyramidal cell layer of CA3. We found that a hippocampal slice can be described by a speed and a direction of propagation of SPW-Rs. The preferred propagation direction was from CA3c (the subfield closer to the dentate gyrus) toward CA3a (the subfield at the boundary to CA2). In patch-clamp recordings from CA3 pyramidal neurons, propagation was estimated separately for excitatory and inhibitory currents associated with SPW-Rs. We found that propagation speed and direction of excitatory and inhibitory currents were correlated. The magnitude of the speed of propagation of SPW-Rs within CA3 was consistent with the speed of propagation of action potentials in axons of CA3 principal cells. KEY POINTS: Hippocampal sharp waves are considered important for memory consolidation; therefore, it is of interest to understand the mechanisms of their generation and propagation. Here, we used two different approaches to study the propagation of sharp waves in mouse CA3 in vitro: multi-electrode arrays and multiple single-cell recordings. We find a preferred direction of propagation of sharp waves from CA3c toward CA3a - both in the local field potential and in sharp wave-associated excitatory and inhibitory synaptic activity. The speed of sharp wave propagation is consistent with the speed of action potential propagation along the axons of CA3 pyramidal neurons. These new insights into the dynamics of sharp waves in the CA3 network will inform future experiments and theoretical models of sharp-wave generation mechanisms.

Social network influence based on SHIR and SLPR propagation models

The rapid progress of science and technology has revolutionized the dissemination of information, with the Internet playing a crucial role. While it has enhanced the ease of sharing information, it has also hastened the transmission of emotions on social media, sometimes resulting in unintended negative outcomes. This research seeks to tackle this issue by suggesting an innovative technique for analyzing social network influence using the Susceptible Hesitant Infected Removed (SHIR) and Susceptible Latent Propagative Removal (SLPR) propagation models. Through the development of an emotional communication model, we take into account the effects of news and public opinion on the rate of emotional communication among individuals. Furthermore, we investigate the impact of various network structures on user behavior. The findings from experiments demonstrate a notable relationship between changes in the density of emotion spreaders and hesitants and the influence of nodes in different network configurations. Specifically, the analysis reveals that the peaks of hesitators and disseminators were lower when the node influence was reduced. Additionally, we verified the precision and dependability of our model by examining data from the Baidu Index, a tool for big data analysis. The margin of error between the model and the actual data was minimal, underscoring the efficacy of our approach. In essence, the study highlights a direct correlation between the speed and extent of emotional propagation in social networks and the degree of nodes. The results showed that the density changes of emotion spreaders and hesitants were significantly correlated with the influence of nodes in different network settings. In the case of node influence of 0.86, the highest peaks of hesitator H and disseminator I were 0.101 and 0.109 lower than those of influence of 1.25. The data analysis of the Baidu Index showed that the maximum peak error of the model was only 0.04, which verified the accuracy and reliability of the model. This investigation carries significant implications for efficiently managing and steering the dissemination of emotions on social media, thereby promoting a healthier online environment.

Effects of partial fuel cracking on the forced ignition and spherical flame propagation in ammonia/air mixtures

As a zero-carbon fuel, ammonia has promising applications and thereby has received great attention recently. However, compared to traditional hydrocarbon fuels, ammonia has very low laminar flame speed and extremely high minimum ignition energy (MIE). A feasible method to promote ammonia combustion is partial fuel cracking, during which ammonia undergoes decomposition into hydrogen and nitrogen. This work reports a computational study on forced ignition and spherical flame propagation in partially cracked ammonia/air mixtures. The objective is to assess the effects of fuel cracking on the MIE and flame propagation. It is found that even a slight amount of ammonia cracking can significantly reduce the MIE and promote ignition. In addition, the influence of positive stretch rate on the spherical flame propagation speed, which is quantified by the Markstein length, is shown to be greatly affected by ammonia cracking. The mechanism of ignition promotion and change in spherical flame propagation by ammonia cracking is interpreted and discussed.

Experimental study on thermal runaway and flame eruption characteristics of NCM523 lithium-ion battery induced by the coupling stimulations of overcharge-penetration

The thermal runaway of lithium-ion batteries under extreme coupled abuse conditions has seriously hindered the sustainable development of lithium-ion new energy vehicles. To reveal the complex thermal runaway behavior mechanism of overcharged lithium-ion batteries induced and by nail penetration, In this paper, a coupled stimulated thermal runaway experimental platform was built, and experimental studies of overcharge-penetration coupled stimulated thermal runaway and flame eruption dynamics were carried out on 18650-type NCM523 lithium-ion batteries from macro and minutiae viewpoints, in which the states of charge (SOC) of the overcharged batteries were 100 %, 105 %, 110 %, 115 %, 120 %, 125 %, 130 %, 135 %, 140 %, 145 % and 150 %. The results showed that the maximum battery surface temperature during overcharging increased from 32.7°C at 100 % SOC to 66.1°C at 150 % SOC, an improvement of 102 %. The thermal runaway battery temperature increased from 529.0°C at 100 % SOC to 657.1°C at 150 % SOC, an increase of 24.2 %. The thermal runaway maximum flame temperature increases from 485.5°C at 100 % SOC to 983.9°C at 150 % SOC, an improvement of 102.6 %. The flame area of medium overcharged> high-level overcharged> low-level overcharged batteries and the flame area of thermal runaway increased by 22213.95 cm2 compared to the maximum of 100 % SOC, and the flame propagation speed of the batteries after thermal runaway showed that the greater the SOC, the stronger the intensity of the flame. The higher the degree of overcharging, the higher the danger of thermal runaway on the side of the battery and near the positive electrode, and the danger of thermal runaway in overcharged lithium-ion batteries increases with the increase of SOC.

“Gear-like” process between asymmetric dipole eddies from satellite altimetry

Mesoscale dipoles compose two counter-rotating mesoscale eddies. They are observed in oceans worldwide and significantly impact the biogeochemical cycle, marine ecosystems, and ocean water transport. This study investigates the evolution of asymmetric dipole eddies based on the satellite altimeter data for the period January 1993–December 2020. The coupling and decoupling of eddy dipoles impact various eddy properties. When the movement of eddies has a dipolar structure, a gentle convergence in parameters (rotational speed, amplitude, eddy kinetic energy, propagation speed, and advective nonlinearity) between the asymmetric dipole eddies is observed–this study refers to it as the “gear-like” process. Kinematic characteristics further indicate that the stronger dipole eddies generally drive the weaker ones to revolve during the “gear-like” process. The revolution direction remains consistent with the rotation direction of stronger dipole eddies. Additionally, eddy size remains relatively stable during the “gear-like” process. The composites of sea level anomaly (SLA) demonstrate that dipole eddies are compressed into a kidney-like shape along the line through their centers. This shape is confirmed by the composites of sea surface temperature anomalies, which closely correspond to the structure of SLA. These findings augment the knowledge regarding the evolution of asymmetric dipole eddies and provide a novel perspective for studying dipoles and eddy-eddy interactions.

Experimental study of NaHCO3/modified vermiculite composite powder for methane explosion suppression

Using a self-constructed experimental platform with 9.5 % methane as the explosive gas, the effects of various masses of NaHCO3, vermiculite, and NaHCO3/modified vermiculite composite powders on the explosion pressure, flame propagation shape, and flame propagation velocity of methane were investigated. The composite powders’ thermal stability and surface microstructure were examined, along with the mechanism of explosion suppression, using thermogravimetric analysis, XRD analysis, and particle size analysis. By comparing various data, 50 wt% NaHCO3/modified vermiculite composite powder with a mass of 360 mg showed the best detonation suppression effect, with Pmax and (dP/dt)max reduced by 53.3 % and 87.1 %, respectively, and Pmax arrival time extended by 142.9 %. The flame disappearance time reached 467 ms, which increased by 165.3 %, and the maximum flame propagation speed decreased by 40 %. Methane explosion suppression is achieved by adding NaHCO3/modified vermiculite composite powder, which prevents flame propagation and breaks the methane explosion chain reaction by chemical and physical suppression of methane explosion.

Kinematic Source Properties of the 2023 Mw 7.7 Türkiye Earthquake Inferred from Near-Fault Strong Ground Motions

Abstract The 2023 Mw 7.7 Türkiye earthquake provided densely observed near-fault ground-motion data, which enabled us to investigate their characteristics and generations. This study aimed to obtain an intuitive understanding of the characteristics of near-fault strong ground motions and their relationship with kinematic source properties using a simple source model. Synthetic ground motions were calculated using the discrete wave number method and compared with observed ground motions. The observed strong motions were used after a time correction based on the first P-wave arrival. Results showed that near-fault pulse-like velocities (0.02–0.6 Hz) were generally explained by the simple kinematic source model that assumed a continuous rupture propagation along the faults. Comparisons at individual sites indicate the various rupture properties of the fault segments. Near-fault ground motions along the Narli segment were explained by the fault plane along the surface trace and not by aftershock distribution. A supershear rupture propagation speed is necessary for a part of the Amanos segment. Rupture stops and restarts were implied near the stepover along the Amanos segment. Empirical site factors estimated by generalized inversion techniques did not show peaks around the frequency of observed large velocity pulses, indicating that the velocity pulses were mainly generated by the source. The model bias and uncertainties were also examined to supplement the simplified subsurface structure used in the simulation. Our results will help to associate the qualitative and quantitative aspects of the kinematic source process with near-fault strong ground motions.

Quantum Retarded Field Engine

Recent efforts to conceptually design a technologically meaningful electromagnetic retarded engine indicated that this can only be done using the immense charge and current densities which exist in the atomic scale. However, this scale cannot be described by Newtonian physics, and only a quantum description will suffice to describe the dynamics of an electron on this scale properly. Here we study the retarded field quantum engine and highlight the differences between the quantum and the classical retarded engines. It is emphasized that the constituents of the retarded engine studied in the current paper do not move in relativistic speeds, hence they are analyzed using un-relativistic classical mechanics and un-relativistic quantum mechanics (Schrödinger’s equations). The retardation effect is due to the finite propagation speed of the field and not the relativistic motion of the particles.

Energy release effect of micro-nano self-assembled aluminum powders and application in composite explosives

Nano aluminum powder effectively enhances reactivity, thereby improving energy-containing materials' performance. To investigate micro-nano self-assembled aluminum powders' energy output and their application in composite explosives, we tested the heat of combustion and ignition characteristics (ignition delay, ignition energy, flame propagation speed) using oxygen bomb calorimetry and Hartmann tube. Results showed that the combustion heat decreased with increasing nano aluminum powder content. The addition of nano aluminum powders substantially decreased ignition delay and energy, enhancing the combustion rate and reactivity of aluminum powder dust. The ranking of reactivity among the five aluminum powders was as follows: μ@n-Al-10 % > μ@n-Al-5% > μ/n-Al-10 % > μ/n-Al-5% > μAl. Assessing explosives containing various aluminum powders showed that the self-assembled 5 % content sample had the highest heat of detonation at 8490 kJ/kg. Mechanical sensitivity increased with higher nano aluminum powder content, with explosives containing 5 % nano content exhibiting the highest safety performance.