•Functionalization of flamboyant pods with citric acid was used to remove Cd2+, Ni2+, Zn2+ and Cu2+.•Carboxylic and phenol functionalities played an important rolein heavy metal ...adsorption.•Endothermic adsorption of tested heavy metals was associated to physisorption.•Adsorption mechanism was analyzed via a physical model with two adsorption sites.
A heterogeneous physical model with two bindings sites (HPMTBS) was successfully used to explain the adsorption of Cd2+, Ni2+, Zn2+, and Cu2+ ions on flamboyant pods functionalized with citric acid. Experimental results and statistical physics modeling showed that carboxylic and phenolic functionalities of this adsorbent played a relevant role for the adsorption of Cd2+, Ni2+, Zn2+, and Cu2+ ions. Calculations performed with HPMTBS suggested that the removal of these cations was a multi-ionic adsorption process at tested operating conditions. This adsorbent was more effective to remove Cd2+, Ni2+, Zn2+ and Cu2+ ions at high solution temperatures thus indicating an endothermic process with adsorption energies ranging from 20.3 to 29.5 kJ/mol, which were associated to physisorption. The total adsorption capacities varied from 0.10 to 0.32, 0.28 to 0.39, 0.19 to 0.25 and 0.20 to 0.31 mmol/g for Cd2+, Ni2+, Zn2+ and Cu2+, respectively. This difference in adsorption capacities could be attributed to the ionic radius of tested adsorbates. This functionalized biomass can be considered as an alternative adsorbent for facing water pollution by heavy metal ions.
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•A magnetostriction model considering elastic potential energy is proposed.•A physics-informed neural network is used to solve the ill-posed physical model.•Magnetostriction is a highly ...stress-dependent phenomenon.•The proposed technique is advantageous for predicting the unknown samples.
The magnetostriction of grain-oriented electrical steels is important for evaluating the core vibrations of operational power transformers. However, magnetostriction is regarded as the square of magnetization in most studies, where influencing factors such as stress and magnetic saturation effects are disregarded. In this study, a two-step magnetostriction-prediction technique based on a physics-informed neural network (PINN) is proposed. First, the physical model of magnetostriction is deduced from the classical Jiles-Atherton model by introducing an elastic potential energy term. Second, a PINN-based model is used to obtain the resulting magnetostriction by adding the residual of the physical equation. The magnetic parameters and magnetostriction of the test specimens are measured experimentally under different excitation voltages and tensile stresses. Results show that magnetostriction is a highly stress-dependent phenomenon. As the tensile stress increases, the elastic potential energy gradually becomes the dominant factor affecting magnetostriction, thereby resulting in a significant amplitude shift in the frequency domain. The performance prediction of the PINN is significantly better than that of artificial neural networks, particularly for unknown samples with slight voltage variations.
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The 1999 Chi-Chi, Taiwan, earthquake (Mw 7.6) caused damage to 49 tunnels within 60 km of the epicenter, including the collapse of three mountain tunnels, ending the traditional perception that ...tunnels, and especially mountain tunnels, were earthquake-resistant. A series of studies that involved seismic damage investigation, physical model and numerical simulation experiments, numerical analyses and field monitoring have been carried out to investigate the damage mechanism, influencing factors and the seismic response of tunnels, and these are reviewed in this manuscript. The results of such studies over the last two decades demonstrate that tunnels suffer less seismic damage than surface structures. Most of seismic damage to tunnels involves failure of the adjacent ground or the movement of a fault that is crossed by the tunnel. Tunnel damage that is caused by ground motion occurs where the seismic effects are amplified, such as at the slope next to mined sections and portals, in shallow overburden tunnels, and at particular combinations of tunnel depth and geological conditions. Results of physical model-based tests using shaking tables and centrifuges reveal that tunnels exhibit rocking responses along with ovaling deformation or racking distortions under seismic excitation; also residual earth pressures remain on the tunnel side walls and internal forces of lining exist after shaking. The structural responses of a tunnel under non-uniform excitation are larger than that under uniform excitation. Beyond investigations of the damage mechanism and influencing factors, physical model-based tests provide experimental benchmarks for correcting numerical model settings and calibrating the characteristic parameters in numerical simulations, and validate the application of such models and simulations in the investigation of tunnel seismic responses. A fully dynamic analysis with complete descriptions of the topography and geological characteristics of a site, and the engineering characteristics of the tunnel and surrounding ground, is nowadays probably the most effective way for the seismic simulation of tunnels, and the design and evaluation of the same. An understanding of the state-of-the-art with respect to the seismic response of tunnels demonstrates the importance of three-dimensional geological models for tunnel seismic analysis; the evaluation of regional ground motion models that can capture the expected range of possible ground motions at tunnel site, and determinations of both the static and dynamic characteristics of geological conditions that are associated with site-scale vulnerabilities. Since residual earth pressures and internal forces remain on tunnel after an earthquake, the seismic damage to tunnels and loads and strain of the surrounding ground may accumulate. Methods for evaluating potential seismic damage to existing tunnels must be further developed, and more field monitoring of the seismic responses of tunnels is required.
•Seismic response of tunnels revealed in past two decades is extensively reviewed.•Ground motion-induced tunnel damage occurs where the seismic effects are amplified.•Seismic damage to tunnels and loads and strain of surrounding ground may accumulate.•3D geological models and more field monitoring are important for fully dynamic analyses.
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•An efficient tool wear monitoring method with multi-channel SCFC features is presented.•A tool breakage monitoring method with amplitude ratio features has been clarified.•The physical models of ...milling force and its induced spindle box vibration and motor torque are proposed.•The decoupling identification for cutter runout, tooth wear loss and respective SCFCs is revealed.•A spindle rotation mark technique with eddy current sensor is given.
Tool wear and breakage is one of the biggest obstacles for developing the unattended CNC machining. Especially when cutting the difficult-to-machining materials, the tool wear will be more rapid and the tool breakage becomes more frequent, which makes an effective tool wear and breakage monitoring very urgent. In the paper, a physical model-based tool wear and breakage monitoring method is proposed. Firstly, a physical model of milling force with the influence of cutter runout and tool wear is established. The spindle box vibration and cutting torque of spindle drive system induced by milling force have been clarified theoretically. Then, through the measurements of milling force, spindle box vibration and driving current, a tool wear monitoring method by extracting the comprehensive feature from the seven-channel specific cutting force coefficients (SCFCs) has been presented. In the method, a multi-parameter decoupling identification procedure for the cutter runout, tooth wear loss and respective SCFCs has been clarified. The force homogenization effect of multi-tooth with tool wear is found. Moreover, an efficient tool breakage monitoring method is further put forward, which incorporates the amplitude ratios of multi-channel data to form an indicator for judging the occurrence of tool damage. The generation mechanism of the sudden distortion on signal waveform resulting from tool breakage is also explained. Finally, long-time milling experiments with multiple groups of machining parameters have been carried out on the general and heavy-cutting machine tools to verify the validity of the proposed method. The verification results indicate that the tool wear and breakage monitoring method can well estimate the cutting status of cutter. The study can provide a useful research basis for the potential industrial application of tool wear and breakage monitoring technology.
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Topography complicates the illumination distribution over rugged terrains and hinders the applications of surface reflectance data over mountainous areas. Topographic correction is an essential ...process to remove the topographic effects in surface reflectance data. This study proposed a Physical model and image Simulation-based topographic Correction method (PSC) for atmospherically corrected surface reflectance images. In contrast with traditional methods, the proposed approach explicitly estimates the illumination distribution over rugged terrains based on image information and then corrects the topographic effects following physical laws. The proposed method was validated and compared with existing well-performed topographic correction methods, including path length correction (PLC), sun-canopy-sensor correction with c factor (SCSC), C correction (CC), and statistical empirical correction (SE). Simulated and satellite data obtained at different times and geolocations are used for evaluation and comparison. The results demonstrated that most existing methods face challenges in removing the biases induced by topography in surface reflectance images. The PLC method failed to obtain reasonable results for faint illumination conditions when the sun zenith angle is high. SE showed relatively poor performance in terms of physical consistency and outlier percentage. Besides, all the traditional methods failed in the correction of cast shadow regions. Comparably, our method consistently demonstrated superior performance in physical consistency, cast shadow correction, and outlier percentage across various regions, encompassing different sun zenith angles and illumination conditions. The proposed method offers an effective and physically consistent approach for the topographic correction of surface reflectance images, facilitating multi-temporal applications over mountainous areas.
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•Adsorption of potential toxic dyes (methylene blue and crystal violet) was studied.•A promising adsorbent was produced and tested during adsorption tests.•A physical model was applied on the entire ...adsorption data set.•Steric explanations supported a better understanding of the adsorption mechanism.•Two energies described the interactive effects of the adsorption systems.
This paper analyzes the adsorption of two potential toxic dyes, i.e. methylene blue (MB) and crystal violet (CV) onto Bauhinia forficata residual fruit powder (BFRFP) as a new promising adsorbent. The experiments aimed at retrievement of adsorption data are carried out at T = 298–328 K and are coupled with an adsorbent characterization to better highlight the MB and CV dyes adsorption mechanism. MB adsorption capacity at saturation (ACS) varies from 181.48 to 201 mg.g−1, while for CV dye, it ranges from 263.06 to 282.61 mg.g−1. This difference is not very significant but reflects that the BFRFP has a higher affinity to remove CV dye. Comparing with some alternative adsorbents, the BFRFP adsorbent shows to be a competitive material for the removal of MB and CV dyes from polluted water. A model assuming that MB and CV dyes are removed via a formation of two layers on BFRFP is chosen as the one that, from a physical point of view, better interpret their adsorption mechanisms. The prediction of the number of dyes adsorbed on BFRFP is approximately equal to 1 for both the dyes, testifying that they are removed without an aggregation process and with slanted position. The physical model generates two energies to describe the interactive effects between both dyes and BFRFP adsorbent (dye- BFRFP) and between dyes (dye-dye). Results show that physical interactions occur during the adsorption process.
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•Bedding plane produced an inevitable effect on the displacement of surrouding rock.•Temperature variations of surrounding rock can reflect the behavior change of surrounding rock.•The transfer path ...of stress during the excavation was achieved.•Driving footage influenced the displacement of tunnel during the excavation processes.
A physical modeling experiment was carried out to study deformation mechanism of tunnel excavated in the deep-buried soft rock strata. During the process of excavation, an infrared camera and a full-field strain measurement system were employed to obtain the thermal response and deformation of surrounding rock. Meanwhile, strain rosettes were used to measuring the strain of surrounding rocks, which were installed with a circular layout pattern in the surrounding rocks. Deformation failure mechanism of surrounding rocks was investigated by synthetic analysis of the infrared images, experimental pictures, and displacement field images. A numerical model was implemented to compare the displacement results of the physical model. The results showed that driving footage produced an effect on the deformation of surrounding rock, the bedding plane had an inevitable influence on the deformation of surrounding rock during the excavation processes and temperature variations of surrounding rock can reflect the behavior change of surrounding rock.
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In this paper, supercritical carbonation tests of concrete specimens with different water-to-cement ratios are carried out. In the test, the thickness of interfacial transition zone (ITZ) of the ...concrete is determined by the distribution of Ca/Si ratio across the interface between the coarse aggregate and cement paste. The microhardness distribution, microstructure and porosity of the ITZ before and after supercritical carbonation are analyzed. A geometrical and physical model considering the distribution of porosity, coarse aggregates, ITZ, and the supercritical carbonation of concrete is proposed, by which cracks, pores, calcium carbonates, and C-S-H gel at the interface of coarse aggregates and cement paste can be studied. The overall microstructures are relatively compacted after supercritical carbonation. The thickness of ITZ of concrete is reduced from 47-79 μm to 35–51 μm after supercritical carbonation. The average value and variance of carbonation depth of concrete increase with the increase of the thickness and porosity of ITZ. Comparing the carbonation results of concrete with different thicknesses and porosity of ITZ, it appears that porosity of ITZ has greater impact on the carbonation depth of concrete.
•Ca/Si ratio distribution can be used to accurately determine the thickness of ITZ.•A method for generating the ITZ between the aggregates and cement paste was proposed.•A geometrical and physical model was proposed for the supercritical carbonation of concrete.•The carbonation depth of concrete is more sensitive to porosity than thickness of ITZ.
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As traditional methods of oil shale production emitting high levels of pollutants, in-situ exploitation has aroused great concerns. In order to study the effect of in-situ pyrolysis products on the ...underground environment, an in-situ oil shale exploitation of underground environment impact laboratory simulation system was designed. Based on the hydrogeological condition of oil shale area in Nong'an City, a physical simulation test was conducted. It was found the temperature of surrounding layers continued to be perturbed after heating of the formation had stopped. The time during which the temperature was perturbed was about 4–5 times the heating period. During the simulation test, stray gas migration through fractures and faults was considered a mechanism for groundwater contamination. In the test, the maximum TOC content in aquifer was the value of 97.0 mg/L. The maximum total petroleum hydrocarbon (TPH) content of the simulated formation was 129 mg/kg after oil pyrolysis.
•A simulation system for in-situ exploitation of oil shale was developed.•The influence of in situ exploitation of oil shale on formation is revealed.•Oil shale exploitation effect on formation temperature field a last long time.•Gas from shale pyrolysis increased organic matter significantly in the upper formation.•An aquifer above the oil shale was significantly contaminated.
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Combined laser–mechanical rock breaking drilling is an emerging technology that uses laser-assisted mechanical rock breaking to efficiently drill wells. A physical model of rectangular and circular ...laser spot scanning rock breaking is developed using the energy conservation theorem and heat transfer related theories, and the reasonableness of the model is analyzed through a combination of experiments and simulations. The effect of two kinds of scanning spots on the strength and drillability of granite was also obtained experimentally, and the effect of two kinds of laser spot scanning on rock breaking was evaluated. The results show that the uniaxial compressive strength of the rock decreases by 24% and 15%, the tensile strength by 20% and 11%, and the drillability by 16% and 10%, respectively, after scanning the granite with rectangular and circular laser spots at the stated parameters, and that the rock breaking effect of the rectangular scanning spot is better than that of the circular scanning spot.
•The mathematical models of the intensity density of the rectangular laser spot and the temperature field of the moving rectangular laser spot following the Gaussian distribution are established.•The simulation and experimental study of rock breaking by rectangular and circular laser spot scanning are carried out, and the influence rules of the two kinds of laser spot scanning granite strength and drillability is analyzed.•The rock breaking effect of the two kinds of scanning light spots in a certain area is optimized through experiments.
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