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Inverting fault geometry and slip distribution simultaneously with geodetic observations based on Bayesian theory is becoming increasingly prevalent. A widely used approach, proposed by (Fukuda and Johnson, Geophys J Int 181:1441–1458, 2010) (F-J method), employs the least-squares method to solve the linear parameters of slip distribution after sampling the nonlinear parameters, including fault geometry, data weights and smoothing factor. Here, we present a modified version of the F-J method (MF-J method), which treats data weights and the smoothing factor as hyperparameters not directly linked to surface deformation. Additionally, we introduce the variance component estimation (VCE) method to resolve these hyperparameters. To validate the effectiveness of the MF-J method, we conducted inversion tests using both synthetic data and a real earthquake case. In our comparison of the MF-J and F-J methods using synthetic experiments, we found that the F-J method's inversion results for fault geometry were highly sensitive to the initial values and step sizes of hyperparameters, whereas the MF-J method exhibited greater robustness and stability. The MF-J method also exhibited a higher and more stable acceptance rate, enabling convergence to simulated values and ensuring greater accuracy of the parameter estimation. Furthermore, treating the fault length and width as unknown parameters and solving them simultaneously with other fault geometry parameters and hyperparameters using the MF-J method successfully resolved the issue of non-uniqueness in fault location solutions caused by the excessively large no-slip areas. In the 2017 Mw 7.3 Sarpol-e Zahab earthquake case study, the MF-J method produced a fault slip distribution with low uncertainty that accurately fit surface observation data, aligning with results from other research institutions. This validated the method's applicability and robustness in real-world scenarios. Additionally, we inferred that the second slip asperity was caused by early afterslip. [ABSTRACT FROM AUTHOR]

Due to geological complexities and observational gaps, it is challenging to identify the governing physical processes of geothermal field deformation including ground subsidence and earthquakes. In the west and east regions of the Heber Geothermal Field (HGF), decade-long subsidence was occurring despite injection of heat-depleted brines, along with transient reversals between uplift and subsidence. These observed phenomena contradict current knowledge that injection leads to surface uplift. Here we show that high-yield production wells at the HGF center siphon fluid from surrounding regions, which can cause subsidence at low-rate injection locations. Moreover, the thermal contraction effect by cooling increases with time and eventually overwhelms the pressure effects of pressure fluctuation and poroelastic responses, which keep relatively stable during geothermal operations. The observed subsidence anomalies result from the siphoning effect and thermal contraction. We further demonstrate that thermal contraction dominates long-term trends of surface displacement and seismicity growth, while pressure effects drive near-instantaneous changes. Thermal contraction effect increases with time dominates the long-term deformation trend of the Heber geothermal field, while pressure effects of pressure fluctuation and poroelastic responses keep relatively stable and drive short-term changes. [ABSTRACT FROM AUTHOR]

Compacted graphite iron (CGI) is considered to be an ideal diesel engine material with excellent physical and mechanical properties, which meet the requirements of energy conservation and emission reduction. However, knowledge of the microstructure evolution of CGI and its impact on flow stress remains limited. In this study, a new modeling approach for the stress–strain relationship is proposed by considering the strain hardening effect and stored energy caused by the microstructure evolution of CGI. The effects of strain, strain rate, and deformation temperature on the microstructure of CGI during compression deformation are examined, including the evolution of graphite morphology and the microstructure of the pearlite matrix. The roundness and fractal dimension of graphite particles under different deformation conditions are measured. Combined with finite element simulation models, the influence of graphite particles on the flow stress of CGI is determined. The distributions of grain boundary and geometrically necessary dislocations (GNDs) density in the pearlite matrix of CGI under different strains, strain rates, and deformation temperatures are analyzed by electron backscatter diffraction technology, and the stored energy under each deformation condition is calculated. Results show that the proportion and amount of low-angle grain boundaries and the average GNDs density increase with the increase of strain and strain rate and decreased first and then increased with an increase in deformation temperature. The increase in strain and strain rate and the decrease in deformation temperature contribute to the accumulation of stored energy, which show similar variation trends to those of GNDs density. The parameters in the stress–strain relationship model are solved according to the stored energy under different deformation conditions. The consistency between the predicted results from the proposed stress–strain relationship and the experimental results shows that the evolution of stored energy can accurately predict the stress–strain relationship of CGI. [ABSTRACT FROM AUTHOR]

It is essential to establish simple, sensitive and accurate quantitative approaches for microRNAs (miRNAs) identification due to its crucial roles in a variety of physiological and pathological processes. Herein, we propose a novel RCA-based colorimetric method for sensitive and reliable miRNA analysis. In this approach, cyclization of the padlock sequence by miRNA-21 initiates the RCA to produce numerous G-rich sequences. The generated G-rich sequences fold to G-quadruplex DNAzyme that is capable of catalyzing cysteine to cystine which could mediate the gold nanoparticle-based color reaction, outputting results that can be observed directly by naked eyes. Based on this, the approach exhibits a wide detection range with a low limit of detection of 4 fM. In addition, the dual target recognition endows the method a greatly improved selectivity. [ABSTRACT FROM AUTHOR]

One of the major concerns in the field of machinery manufacturing of Ni-based superalloys is machining-induced surface integrity, since the surface integrity is closely bound up with the service performance of machined components. In the current study, a range of orthogonal experiments are carried out to investigate the surface integrity characteristics, including surface morphology, surface roughness, residual stress, work hardening, and surface microstructure during high-speed milling of Inconel 690. The results show that both cutting speed and feed rate plays a constructive role in determining cutting force and surface integrity of Inconel 690. The cutting force displays a downtrend with the increase of cutting speed while presents an uptrend with the increase of feed rate as well as depth of cut. While, no clear tendency between the relative position of tool and workpiece and the cutting force could be found. The surface roughness decreases firstly and then increases slightly with the increase of cutting speed while increases with the increase of feed rate. The surface residual stress presents more tensile tendency as the cutting speed and feed rate increase. Similarly, the increased cutting speed and feed rate strengthen the degree of work hardening as well as depth of work hardening. It is worth mentioning that not only the depth of cut but also the relative position of tool and workpiece has little effect on surface integrity. Severe plastic deformation occurs in the microstructure of machined surface layer. No phase transformation is observed at all workpiece surface. This study provides a meaningful chance to achieve excellent machining-induced surface integrity via selecting suitable cutting parameters. [ABSTRACT FROM AUTHOR]

Twelve Sentinel-1 images are used to measure the surface displacements caused by the Zaduo earthquake on 17 October 2016 in Qinghai, China. Comprehensive analysis of the local geologic structure, focal mechanisms, relocated aftershocks, and fault geometrical parameters from nonlinear inversions of the InSAR data indicates that a NE-trending fault with a strike of ~ 61°, namely the Aduo fault, was responsible for this event. Further geodetic inversions for finite fault models show that the dip angle of this fault is 75° to the SE. The majority of the slip occurred at the depth from 5 km to 17 km, and the normal-slip component was comparable to the strike-slip component. The peak slip of ~ 31 cm occurred at a depth of ~ 10 km. The InSAR determined moment is 9.61 × 1017 N m with a rigidity of 30 GPa, equivalent to Mw 5.9. The geological map reveals that the Aduo fault was characterized by a left-lateral strike-slip component in the past, as evidenced by the offset of Paleogene sedimentary rocks. Our results for the Zaduo earthquake suggest that the Qiangtang block probably consists of two or more sub-blocks with different eastward extrusion velocities and that the deformation of the Qiangtang block is occurring not only along its boundaries but also in its interior. [ABSTRACT FROM AUTHOR]

Compacted graphite iron (CGI) is an ideal material for the cylinder block and cylinder head of diesel engine because of its excellent physical and mechanical properties. At present, the researches on CGI mainly focused on experimental study of machining CGI, there are few studies on the cutting simulation of CGI, especially the high-speed machining simulation of CGI, and the constitutive equation of CGI at high temperature and high strain rate has not been studied. In this paper, the stress-strain relationship under quasi-static condition was obtained by quasi-static tensile test, and the power law constitutive equation of CGI with a grade of GJV450 under the condition of large strain, high strain rate, and high temperature was built by orthogonal cutting experiments and finite element iteration. The established power law constitutive equation was applied to the finite element simulation of the cutting process of CGI, which improves the accuracy of finite element analysis. The chip morphology of CGI and the distribution of plastic strain and temperature in the cutting process were analyzed by finite element simulation. [ABSTRACT FROM AUTHOR]