Flux Components Research Articles

On the contribution of cosmic-ray interactions in the circumgalactic gas to the observed high-energy neutrino flux

Cosmic rays escaping the Milky-Way disk interact with circumgalactic gas which fills the virial volume of our Galaxy. These interactions should produce guaranteed fluxes of energetic diffuse neutrinos and photons observable at the Earth. This neutrino flux would be a plausible contribution to the spectrum measured by the IceCube neutrino observatory: the energy emitted in this way is weakly constrained from cascade gamma rays, since the cascades have no time to develop, but the arrival directions of the neutrinos do not point to the Galactic disk, in agreement with observations. However, previous studies reported very different estimates of the corresponding neutrino flux, so it was unclear if this contribution to the observed spectrum is essential. Here we readdress the calculation of this diffuse neutrino flux component under various assumptions about the cosmic-ray spectrum and propagation in the circumgalactic medium. We find that even with these variations, this contribution to the observed neutrino flux remains subleading provided multimessenger constraints are satisfied.

PVA/UiO-66 mixed matrix membranes for n-butanol dehydration via pervaporation and effect of ethanol

In this work, pervaporative mixed matrix membranes (MMMs) composed of porous UiO-66 filler newly-synthesized and poly (vinyl alcohol) (PVA) have been investigated for dewatering n-butanol (BuOH) from BuOH/H2O and BuOH/ethanol/H2O solutions. The influences of the filler loading, feed concentration and feed temperature on the membrane dehydration performance are investigated in detail in terms of pervaporation flux/separation factor, pervaporation separation index and component permeance/selectivity. It is found that with the increase in feed water concentration or temperature, total permeation flux across the MMM substantially rises while the dehydration separation factor decreases considerably. With the increase in feed temperature, pronounced increase in the driving force is resulted, yielding the decline in the partial permeance and water/n-butanol selectivity but increase in the component flux. As the water content increases, the water permeance and water/n-butanol selectivity are reduced while both BuOH flux and permeance increase. Over the filler loading range considered here, the MMM with 15 wt% UiO-66 has reached the largest pervaporation separation index of 2560 kg/m2·h at 70 °C and 10 wt% water in the feed. In the case of using 10 wt% ethanol for BuOH in the feed, the dewatering separation performance has varied substantially as compared to the binary feed, leading to reduced separation factor and elevated permeation flux for the 15 wt% UiO-66 filled MMM. In the meantime, the MMM has maintained excellent separation performance over a testing duration of 240 h. Our results show that pervaporative UiO-66/PVA MMMs have demonstrated great potential in practical BuOH dehydration applications.

Probing the Variation of Reverberation Lags along with X-Ray Flux in the AGN Mrk 704

Understanding the variation of lags with respect to the X-ray flux is important to explore the geometry of the inner region of the accretion disk in AGNs. We performed frequency-lag, energy–lag and spectral studies for two sets of observations, in order to investigate the variations in lags with respect to X-ray flux in the AGN source Mrk 704 using the XMM-Newton observatory. We divided one of the light curves into two sections which were noticed to exhibit a flux variation. The frequency-lag spectra in different energy domains revealed that reverberation (soft) lags varied along with the flux. For the first time, we show that the blurred reflection model can consistently explain the soft excess observed in the X-ray spectra for this source. The fluxes of soft (i.e., reflection) and hard components were noted to vary by ∼18% and ∼9% respectively, across the sections. The soft lag amplitude was found to be larger at the high flux state than the amplitude at the low flux state. Most importantly, we found that both frequency-lag and energy–lag spectra do not display significant variation between two observational data sets despite a flux variation of 43%. This phenomenon cannot be explained by the reflection model because the soft lag amplitudes must be larger in the high flux state. The probable scenario is that, in the low flux state, the obscuring cloud delays the reflected soft photons which increases the soft lag amplitude.

What does a typical full disc around a post-AGB binary look like?

Context.Stable circumbinary discs around evolved post-asymptotic giant branch (post-AGB) binary systems composed of gas and dust show many similarities with protoplanetary discs around young stellar objects. These discs can provide constraints on both binary evolution and the formation of macrostructures within circumstellar discs. Here we focus on one post-AGB binary system: IRAS 08544-4431.Aims.We aim to refine the physical model of IRAS 08544-4431 with a radiative transfer treatment and continue the near-infrared and mid-infrared interferometric analysis covering theH,K,L, andNbands. Results from geometric modelling of these data in our previous study constrain the shape of the inner rim of the disc and its radial dust structure. We aim to capture the previously detected amount of over-resolved flux and the radial intensity profile at and beyond the inner dust disc rim to put constraints on the physical processes in the inner disc regions.Methods.We used a three-dimensional Monte Carlo radiative transfer code to investigate the physical structure of the disc by reproducing both the photometry and the multi-wavelength infrared interferometric dataset. We first performed a parametric study to explore the effect of the individual parameters and selected the most important parameters, which were then used in a thorough grid search to fit the structural characteristics. We developed a strategy to identify the models that were best able to reproduce our extensive multi-wavelength dataset.Results.We find a family of models that successfully fit the infrared photometric and interferometric data in all bands. These models show a flaring geometry with efficient settling. Larger grains are present in the inner disc as probed by our infrared interferometric observations. Some over-resolved flux component was recovered in all bands, but the optimised models still fall short in explaining all the over-resolved flux. This suggests that another dusty structure within the system that is not included in our models plays a role. The structure of this over-resolved component is unclear, but it has a colour temperature between 1400 and 3600 K.Conclusions.Multi-wavelength infrared interferometric observations of circumstellar discs allow the inner disc regions to be studied in unprecedented detail. The refined physical models can reproduce most of the investigated features, including the photometric characteristics, the radial extent, and the overall shape of the visibility curves. Our multi-wavelength interferometric observations combined with photometry show that the disc around IRAS 08544-4431 is similar to protoplanetary discs around young stars with similar dust masses and efficient dust growth. The resulting disc geometry is capable of reproducing part of the over-resolved flux, but to fully reproduce the over-resolved flux component, an additional component is needed. Multi-scale high-angular-resolution analysis combining VLTI, VLT/SPHERE, and ALMA data is needed to fully define the structure of the system.

Fluxes and Composition of Particulate Matter in the Water Column of South Baikal (between March 2015 and March 2016)

Abstract —The paper provides the results of experiments with sediment traps in the deep-water part of the South Basin of Lake Baikal (depth of 1366 m), installed from March 2015 to March 2016 in order to study recent sedimentation within the lake. We present new data on total fluxes of particulate matter and fluxes of biogenic components (SiO2biog, Сorg, and Ntot) at different depths of the water column both for the whole year and for individual periods of the year. Diatom analyses were carried out for all obtained samples. The total flux of sedimentary material averaged 94.9 g/m2/y; the average fluxes of SiO2biog, Сorg, and Ntot were 23.9, 11.6, and 0.94 g/m2/y, respectively. The molar C/N ratio varies from 11 to 21 and indicates a predominance of allochthonous material in almost all samples. Maximum fluxes of sedimentary matter were recorded from 20 June to 20 July 2015. This period corresponds to the bloom of diatoms of the species Synedra acus. This species amounts to >94% of the total diatom content in all samples taken during this year. The recent predominance of Synedra acus in the water column, as well as in the surface bottom sediments of South Baikal, is probably due to the climate warming.

Analytical model for the combined effects of rotation and collisionality on neoclassical impurity transport

The influence of rotation, collisionality and trapped particle fraction on the magnitude and direction of neoclassical impurity transport in tokamaks is analyzed using an extensive database of drift-kinetic simulations with the NEO code. It is shown that an operational window opens at sufficiently high Mach number and low collisionality, where the magnitude of the temperature screening of impurities increases with higher rotation. If the collisionality increases, this effect is quickly lost and the temperature gradient then drives an inward impurity flux when rotation is present. The boundary between these two regimes is calculated as a function of the trapped particle fraction, and it is shown that plasma parameters achieved in recent JET experiments allow them to access the new beneficial regime, in accordance with observations of reduced tungsten accumulation. Applications to ASDEX Upgrade experiments where these effects become relevant are also presented, and the implications for ITER are discussed. A method for extracting the physically distinct Pfirsch–Schlüter (PS) and banana-plateau (BP) neoclassical flux components from the NEO output is introduced and employed to construct a model that describes them analytically at arbitrary rotation and collisionality. The beneficial behavior of the screening with rotation is found to be a BP effect, in contrast to the known detrimental role of rotation in the PS component. The new analytical model is able to reproduce the results of NEO when modeling radial profiles of transport coefficients from experimental kinetic profiles, with the added feature of isolating the BP and PS components for additional physical analysis, while remaining well suited for fast applications.

Evidence to disfavour dual-core systems leading to double-peaked narrow emission lines

ABSTRACTIn this paper, an interesting method is proposed to test dual-core systems for double-peaked narrow emission lines through a precious dual-core system with double-peaked narrow Balmer lines in the main galaxy but with single-peaked narrow Balmer lines in the companion galaxy. Under a dual-core system, considering narrow Balmer (Hα and Hβ) emissions (fe,α and fe,β) from a companion galaxy that are covered by the SDSS fiber for the main galaxy and narrow Balmer emissions (fc,α and fc,β) from the companion galaxy covered by the SDSS fiber for the companion galaxy, the same flux ratios fe,α/fc,α = fe,β/fc,β can be expected, owing to the totally similar physical conditions of each narrow Balmer emission region. Next, the precious dual-core system in SDSS J2219–0938 is discussed. After subtracting the pPXF code determined stellar lights, double-peaked narrow Balmer emission lines are confirmed in the main galaxy with a confidence level higher than 5σ, but single-peaked narrow Balmer emission lines are confirmed in the companion galaxy. Through measured fluxes of the emission components, fe,α/fc,α is about 0.82, which is different from fe,β/fc,β ∼ 0.52, which disfavours a dual-core system for the double-peaked narrow Balmer emission lines in SDSS J2219–0938.

Spatial and seasonal variations in the particulate sinking flux in the Bay of Bengal

Sediment traps have been widely used to study particles sinking through the oceanic water column. As part of the SIBER-INDIA program, sediment traps were deployed at three depths − 430 m (shallow), 1020 m (middle), and 1555 m (deep) on a mooring line in the northern BoB (Bay of Bengal Sediment Trap, BoBST). We present here data on fluxes, concentrations, and isotopic composition of carbon and nitrogen, for the period 2011–2012 for all three traps, and the shallow (505 m) and middle (1035 m) traps for 2019–2020. The mooring site was largely influenced by riverine water in 2011–2012 and the increase in flux during the southwest monsoon was attributed to both autochthonous production and a high influx of river-supplied material. On the other hand, the contribution of the lithogenic matter was less in 2019–2020. The weak sea level anomaly (SLA) signal showed that the influence of cyclonic eddies at the mooring location was minimal during the deployment period in 2011, whereas a cyclonic eddy seems to have contributed to the higher flux seen in May-June 2019. To delineate the long-term changes in the component fluxes, data collected during 2011–2012 and 2019–2020 were compared with earlier available data from the Northern Bay of Bengal Traps (NBBT-N). The annual carbonate fluxes in the present study (9.3 and 7.1 g m−2 y-1 in 2011 and 2019, respectively in the ∼ 1000 m trap, and 7.7 g m−2 y-1 in the deep trap in 2011) were low compared to earlier (1987–1997) data of NBBT-N (10.9–14.7 g m−2 y-1; avg. 13.1 ± 1.4 g m−2 y-1 for ∼ 1000 m traps and 12.0–16.1 g m−2 y-1; avg. 13.3 ± 1.3 g m−2 y-1 for deep traps). On the other hand, the opal fluxes were higher in 2011 as compared to earlier (1987–1997) and 2019 data. This is also reflected in the abundance of silicifiers, which was much higher in 2011 mainly supported by significant dissolved silica in the river runoff and from the lithogenic material dissolved in the seawater. The present study highlights the seasonal and inter-annual variations in riverine suspended particulate material in the BoB and warrants the continuation of time-series studies to infer long-term changes in the component fluxes.

Modeling Solar Orbiter dust detection rates in the inner heliosphere as a Poisson process

Context.Solar Orbiter provides dust detection capability in the inner heliosphere, but estimating physical properties of detected dust from the collected data is far from straightforward.Aims.First, a physical model for dust collection considering a Poisson process is formulated. Second, it is shown that dust on hyperbolic orbits is responsible for the majority of dust detections with Solar Orbiter’s Radio and Plasma Waves (RPW). Third, the model for dust counts is fitted to Solar Orbiter RPW data and parameters of the dust are inferred, namely radial velocity, hyperbolic meteoroids predominance, and the solar radiation pressure to gravity ratio as well as the uncertainties of these.Methods.Nonparametric model fitting was used to get the difference between the inbound and outbound detection rate and dust radial velocity was thus estimated. A hierarchical Bayesian model was formulated and applied to available Solar Orbiter RPW data. The model uses the methodology of integrated nested Laplace approximation, estimating parameters of dust and their ncertainties.Results.Solar Orbiter RPW dust observations can be modeled as a Poisson process in a Bayesian framework and observations up to this date are consistent with the hyperbolic dust model with an additional background component. Analysis suggests a radial velocity of the hyperbolic component around (63 ± 7) km s−1with the predominance of hyperbolic dust being about (78 ± 4)%. The results are consistent with hyperbolic meteoroids originating between 0.02 AU and 0.1 AU and showing substantial deceleration, which implies effective solar radiation pressure to a gravity ratio ≳ 0.5. The flux of the hyperbolic component at 1 AU is found to be (1.1 ± 0.2) × 10−4m−2s−1and the flux of the background component at 1 AU is found to be (5.4 ± 1.5) × 10−5m−2s−1.

Modelling and optimal control of growth, energy, and resource dynamics of Hermetia illucens in mass production environment

Mass production of Hermetia illucens insect larvae is now being adopted in many countries and is taking an industrial production approach. Despite abundant literature on factors that affect larvae growth and the optimal static parameters identified in laboratory setup, for an industrial production process it is necessary to identify the trajectories such that the growth as well as the production process is optimal. To achieve this in this work, some of the important requirements and challenges involved thereof are identified and objectives of the automation process are formulated within a model based optimal control setup. Mechanistic models necessary for the optimization framework are derived as differential equations that describe the dynamic variation of resources (feed, water, O2 etc.), energy, and larval biomass. In addition, the elevated metabolic activity of larvae corresponding to the final instar development is identified and also modelled based on the observation from experiments. The mass and energy balance approach used in modelling enables the quantification and distinction of the mass and energy flux components in various levels (e.g. larvae body, growing medium, production environment, and external environment) while holding its applicability for both open and closed/reactor based production setups. Finally, the trajectories generated using the synthesized optimal controller are tested under different scenarios showcasing significant reduction in resource consumption compared to a constant set-point operation of the production setup. Results presented in this work not only showcase the potential of the mechanistic models and their application in identifying the relevant process parameters (e.g. reactor properties such as volume, thermal conductivity, actuator capacities), but most importantly in optimizing the process dynamically and tuning the process objectives as desired (e.g. maximize larvae mass, reduce energy).

Green tea extract and Piper retrofractum attenuate deoxycholic acid-induced damage and enhance the tight junction barrier: An analysis in a Caco-2 cell culture model and a DSS coinduced mouse model

This study investigated the effect of green tea extract (GTE) and green tea–Piper retrofractum complex (GPX), on tight junctions (TJs) in a cellular model of deoxycholic acid (DCA)-induced intestinal barrier disruption and a mouse DSS + DCA-induced colitis model. Green tea and P. retrofractum were extracted and coadministered to examine the bioavailability and effects of combined catechins and piperine on colonic TJ damage. The ability of GPX to alleviate TJ damage was determined by comparing the transepithelial electrical resistance (TEER), FITC-dextran flux, and mRNA expression of TJ-related components and target expression pathway in the GTE and GPX groups. Compared with the DCA-treated group, the GTE- and GPX-treated groups showed significantly enhanced TEER, FITC-dextran flux, and TJ-related mRNA expression (p < 0.05). Cell treatment also downregulated the mRNA encoding bile acid receptor and decreased ERK1/2 phosphorylation. Compared with the GTE-treated group, the GPX-treated group showed higher mRNA expression of zonula occludens-1, occludin, claudin-3, and claudin-4; greater restoration of TJs, as determined by immunofluorescence; and better modulation of ERK1/2 activation. In the in vivo model, GPX-pretreated mice showed an improved intestinal damage index and colon length compared with mice in the other colitis-induced groups. Both extracts recovered the distal colon mRNA expression of zonula occludens-1 and claudin-1. These results suggest that GTE improves intestinal health by protecting TJs from secondary bile acid damage and that P. retrofractum may potentiate the bioactivity of green tea catechins.

Estimating degree-day factors of snow based on energy flux components

Abstract. Meltwater from mountainous catchments dominated by snow and ice is a valuable source of fresh water in many regions. At mid-latitudes, seasonal snow cover and glaciers act like a natural reservoir by storing precipitation during winter and releasing it in spring and summer. Snowmelt is usually modelled either by energy balance or by temperature-index approaches. The energy balance approach is process-based and more sophisticated but requires extensive input data, while the temperature-index approach uses the degree-day factor (DDF) as a key parameter to estimate melt of snow and ice merely from air temperature. Despite its simplicity, the temperature-index approach has proved to be a powerful tool for simulating the melt process especially in large and data-scarce catchments. The present study attempts to quantify the effects of spatial, temporal, and climatic conditions on the DDF of snow in order to gain a better understanding of which influencing factors are decisive under which conditions. The analysis is based on the individual energy flux components; however, formulas for estimating the DDF are presented to account for situations where observed data are limited. A detailed comparison between field-derived and estimated DDF values yields a fair agreement with bias = 0.14 mm ∘C−1 d−1 and root mean square error (RMSE) = 1.12 mm ∘C−1 d−1. The analysis of the energy balance processes controlling snowmelt indicates that cloud cover and snow albedo under clear sky are the most decisive factors for estimating the DDF of snow. The results of this study further underline that the DDF changes as the melt season progresses and thus also with altitude, since melting conditions arrive later at higher elevations. A brief analysis of the DDF under the influence of climate change shows that the DDFs are expected to decrease when comparing periods of similar degree days, as melt will occur earlier in the year when solar radiation is lower, and albedo is then likely to be higher. Therefore, the DDF cannot be treated as a constant parameter especially when using temperature-index models for forecasting present or predicting future water availability.

Global net biome CO2 exchange predicted comparably well using parameter-environment relationships and plant functional types.

Accurate estimation and forecasts of net biome CO2 exchange (NBE) are vital for understanding the role of terrestrial ecosystems in a changing climate. Prior efforts to improve NBE predictions have predominantly focused on increasing models' structural realism (and thus complexity), but parametric error and uncertainty are also key determinants of model skill. Here, we investigate how different parameterization assumptions propagate into NBE prediction errors across the globe, pitting the traditional plant functional type (PFT)-based approach against a novel top-down, machine learning-based "environmental filtering" (EF) approach. To do so, we simulate these contrasting methods for parameter assignment within a flexible model-data fusion framework of the terrestrial carbon cycle (CARDAMOM) at a global scale. In the PFT-based approach, model parameters from a small number of select locations are applied uniformly within regions sharing similar land cover characteristics. In the EF-based approach, a pixel's parameters are predicted based on underlying relationships with climate, soil, and canopy properties. To isolate the role of parametric from structural uncertainty in our analysis, we benchmark the resulting PFT-based and EF-based NBE predictions with estimates from CARDAMOM's Bayesian optimization approach (whereby "true" parameters consistent with a suite of data constraints are retrieved on a pixel-by-pixel basis). When considering the mean absolute error of NBE predictions across time, we find that the EF-based approach matches or outperforms the PFT-based approach at 55% of pixels-a narrow majority. However, NBE estimates from the EF-based approach are susceptible to compensation between errors in component flux predictions and predicted parameters can align poorly with the assumed "true" values. Overall, though, the EF-based approach is comparable to conventional approaches and merits further investigation to better understand and resolve these limitations. This work provides insight into the relationship between terrestrial biosphere model performance and parametric uncertainty, informing efforts to improve model parameterization via PFT-free and trait-based approaches.

Numerical Simulation of Temporal Variability of Methane Emissions from Mozhaysk Reservoir

Estimates of methane emission from the Mozhaysk reservoir surface were carried out using the mathematical model LAKE2.3. The average emission value is 361 tC per year, the average flux = 37.7 mgC–CH4 m–2 day–1. Comparison of the obtained estimates with in situ measurements revealed, that the methane emission and specific flux according to the model are in good agreement with the observations data. The ebullition makes the largest contribution to the total emission. During the heating period, an increase of methane emission is observed with a maximum before the autumn mixing stage. In the course of numerical experiments with the model, it was found that the amplitude of methane fluxes into the atmosphere is associated with fluctuations in atmospheric pressure, and the most significant emissions peaks associated with water level drawdowns. Effective method for calibrating the diffusion component of the methane flux into the atmosphere is the potential rate of methane oxidation in the Michaelis-Menten reaction, and for ebullition it is the methane generation parameter in bottom sediments — q10. For the described numerical experiments, the article presents the values of the annual emissions of methane into the atmosphere.

Регистрация радиационного теплового потока в ударной трубе с помощью термоэлектрического детектора

The results of experimental studies on registration of the radiative component of the total heat flux by a thermoelectric detector in a reflected shock wave are presented. An increase in the contribution of radiation to the heat flux with an increase in the intensity of the shock wave is estimated. It is shown that the technique can be used in experiments in shock tubes to isolate the radiative component of the total heat flux, and the thermoelectric detector itself can be successfully used to record such parameters.

Design and Analysis of Novel Three-Phase PFC for IM Drives

Induction motor drives (IMDs) can achieve high performance levels comparable to dc motor drives. A major problem in getting high dynamic performance in an IMD is the coupling between the flux and torque producing components of stator current. This is successfully overcome in FOC (Field-Oriented Control) IM, making it to the industry standard control. The performance of an IMD with an improved power quality converter at the front end is presented in this study. In the IMD, boost converter is employed to reduce power quality difficulties at the utility interface. As the boost converter contains only one switch, it results in a low processing time and cost. To ensure sinusoidal supply currents with high PF (Power Factor) and minimal THD (Total Harmonic Distortion), a novel PFC (Power Factor Corrector) control technique is proposed. To enhance the performance of the converter and to lower distortions at the motor side, PI (Proportional Integral) controller is incorporated at the PFC side. Thus it controls the DC bus voltage. The proposed boost converter improves power quality by lowering overall harmonic distortion of AC mains current, improving power factor correction, and regulating dc-link voltage. It is designed, modelled, and simulated in the MATLAB/simulink platform. Using a DSP (Digital Signal Processor), the suggested system’s performance is experimentally validated. The system’s performance is evaluated for speed and load torque, and the power quality indices are determined to meet IEEE-519 standards under all operating conditions. From the obtained results, it is evident that the proposed system mitigates the power quality issues effectively.

A Passive Negative Magnetic Reluctance Structure-Based kHz Transformer for Improved DC Magnetic Bias Withstanding

How to effectively withstand the dc magnetic bias is one of the key aspects of transformer design. General approaches either require additional active power electronics devices or apply complicated control strategies, causing the increased cost or reduced reliability. In this article, a passive negative magnetic reluctance structure (NMRS) is proposed and installed in the air gap of the open-core transformer, which could achieve improved dc magnetic bias withstanding capability without extra active devices. The key criterion of the proposed design is to employ the NMRS with a frequency-variation magnetic reluctance property as a magnetic bandpass filter, which shows a negative equivalent magnetic reluctance for the fundamental component of flux. Nevertheless, it presents a high magnetic reluctance for the dc component. With the proposed design, the transformer provides a strong withstanding dc bias capability and a low magnetizing current as well as high efficiency. Accordingly, both the advantages of open-core and closed-core transformers could be obtained with the proposed design. For verification, a 500-W EE55-based core prototype is constructed and verified with sinusoidal and square wave excitation. Electromagnetic analysis and experimental results are provided to demonstrate the effectiveness of the proposed design.

Flux growth and phase diversity of the triple oxides of transition metals (Mn,Fe,Ga)2O3in multicomponent fluxes based on Bi2O3–MoO3–B2O3–Na2O

The influence of Bi2O3–MoO3–B2O3–Na2O flux components on the crystallization of the triple oxides (Mn,Fe,Ga)2O3is studied. 9 single crystal samples of bixbyite, spinel and orthorhombic phase are obtained and characterized.

A study of the problem of compositional analysis of ancient glassware based on grey models

In ancient times, glass was a valuable object of trade between China and the West, with potassium glass and lead-barium glass being common. In order to classify and identify ancient glass objects, this paper establishes a relevant classification model based on the chemical composition of glass, which is of some significance for the classification and analysis of glass. In this paper, the frequency distribution of each component is plotted as non-standard normal distribution, and then Spearman correlation coefficient is selected to describe its correlation, and it is found that SiO₂ has a more active relationship with other components, so it is chosen as the reference column for grey correlation analysis, and it is concluded that SiO₂ is closely related to the flux component of its glass type.

Welding arc energy characteristic regulation

When welding pipes, due to the concentration of magnetic field lines in a ferromagnetic pipe with high magnetic permeability, the welding current magnetic field increases, magnetic blow, under. by the action of electromagnetic force, the arc length increases up to a break, the current and voltage on the arc fluctuate significantly, the seam dimensions change from a point to a large width, the process stability is disturbed, the welds formation and the welded joints impact toughness is reduced. Based on the study of the arc energy characteristics, according to which the voltage on the arc increases with increasing arc length, it was found that the arc moves along the tape end at a speed of 3.3 m/s, the electrode shape affects the welding arc. energy and voltage characteristics. In this case, the sum of near-electrode voltage drops depends on the work function of electrons from the cathode surface of the flux components and does not depend on the electrode shape, which confirms the main role of field emission in the arc and the arc concentration below. pinch-effect. To increase the welded joints impact toughness, it is necessary to reduce energy, heat input, crystal lattice microdistortions, microstresses, dislocation density, welding stresses, reduce the weld width, heat-affected zone, the deposited metal amount and refine the microstructure. An effective way to reduce energy is to increase the welding speed, which reduces the heat input, and reduce the arc length, arc voltage, which leads to an increase in the arc rotation speed, pinch effect, arc concentration and energy, heat input efficiency, reduce welding stresses, increase the crystallization rate, the microstructure refinement, the interatomic distance reduction and interatomic bonds increase. A process for one-sided high-speed welding of pipes for gas and oil pipelines with a low-energy composite electrode, which, due to low arc voltage, arc concentration, stability, energy reduction, heat input, welding stresses, microstructure refinement, interatomic distance reduction and interatomic bonds increase, provides an increase in the welded joints impact toughness 2-2.5 times has been developed. Minimum energy – maximum welded joints impact toughness