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• Effect of dry-wet cycles on strength of cemented broken mudstone (CBM). • Prediction model of dynamic compression strength (DCS) based on ultrasonic detection. • Effect of dry-wet cycles on microstructure and hydration of CBM. • Influence mechanism of strain rate and dry-wet cycles on CBM. The secondary utilization of abandoned mine is usually accompanied by water erosion, cyclic impact, and induced earthquake, which induces a great engineering challenge for the mudstone stratum reconstruction. Consequently, this paper carried out ultrasonic detection, split Hopkinson pressure bar (SHPB) impact, thermogravimetry, and mercury intrusion porosimetry tests to investigate the dynamic performance and microstructure of reinforcing mudstone under water erosion. The results show that the dynamic compression strength (DCS) and strain-rate enhancement effect of cemented broken mudstone (CBM) firstly increase and then decrease with the increase of dry-wet cycles, the maximum growth is 15.38% for CBM in 3 dry-wet cycles while the maximum drop is 19.63% for that in 9 dry-wet cycles. The dry-wet cycles mainly affect the DCS by changing the elastic limit strength, and promote the carbonization of Ca(OH) 2 to produce up to 9.365% CaCO 3 during the cemented matrix's hydration. In the late dry-wet stage, the deterioration of internal mudstone particles induces pore cracks and causes up to 19.63% decrease in DCS. This study reveals the evolution law of dynamic mechanical properties of CBM under water erosion, and provides experimental reference for the reconstruction of abandoned mine. [ABSTRACT FROM AUTHOR]

Measuring 3-D mining-induced displacements is essential to understand mining deformation mechanisms and assess mining-related geohazards. In our previous work, we proposed a method for estimating 3-D mining-induced large displacements with the surface deformation along the radar line-of-sight (LOS) direction derived from a single amplitude pair (SAP) of synthetic aperture radar (SAR) using the offset tracking (OT) procedure (hereafter referred to as OT-SAP). The OT-SAP method effectively reduces the strict requirements on SAR data of the previous OT-based methods for 3-D mining-induced displacement retrieval. However, OT-SAP is not robust to errors in the LOS deformation, due to the lack of redundant observations. In this paper, we present an alternative approach (hereafter called AOT-SAP) to OT-SAP. The AOT-SAP method involves estimating the 3-D mining-induced large displacements with OT-derived 2-D deformation observations along the LOS and azimuth directions from an SAP of SAR, instead of just the LOS deformation in the OT-SAP method. Consequently, more redundant observations are incorporated in the AOT-SAP method compared with the previous OT-SAP method. The theoretical analysis and experiments based on both simulated and real data sets suggest that AOT-SAP can effectively improve the accuracies of the estimated 3-D displacements compared with the OT-SAP-estimated ones. [ABSTRACT FROM AUTHOR]

This paper presents a novel method for modeling and robustly estimating the time-series 3-D mining-induced large displacements from a single imaging geometry (SIG) synthetic aperture radar (SAR) amplitude data set using the offset-tracking (OT) technique (hereafter referred to as the OT-SIG). It first generates multitemporal observations of 3-D mining-induced displacements from the single-geometry SAR amplitude data set with the assistance of a prior model. Then, a functional relationship between mining-induced time-series 3-D displacements and the multitemporal 3-D deformation observations generated is constructed. Finally, the time-series 3-D displacements are robustly estimated based on the constructed function model using the M-estimator. The proposed OT-SIG provides a robust and cost-effective tool for retrieving time-series 3-D mining-induced large displacements, relaxing the basic requirement of the traditional method that at least two different viewing geometries’ SAR data are needed. Finally, we tested the proposed OT-SIG with descending TerraSAR-X SAR amplitude data set over the Daliuta coal mining area in China. The results show that the root-mean-square errors (RMSEs) of OT-SIG-estimated time-series displacements are about 0.22 and 0.11 m in the vertical and horizontal directions, respectively. These RMSEs are around 5.7% and 10.9% of the maximum in situ deformation measurements in the corresponding directions, which can meet the accuracy requirements of practical applications. [ABSTRACT FROM AUTHOR]

Underground extraction can be roughly classified into three types, i.e., subcritical, critical, and supercritical extraction, in accordance with the geological conditions in the overburden and the geometry of mined-out areas. In 2016, we proposed an approach based on the interferometric synthetic aperture radar (InSAR) technique and the probability integral method (PIM) for the cost-effective prediction of 3-D mining-induced displacements (abbreviated as InSAR-PIM). Due to the inherent assumption of critical extraction in the PIM, the InSAR-PIM method performs well in predicting the 3-D displacements caused by critical and/or supercritical extraction, but poorly for subcritical extraction. In this paper, we first propose a generalized PIM (GPIM) by modifying the traditional PIM with a simplified Boltzmann function. We then replace the PIM of the InSAR-PIM with the proposed GPIM to develop an extension of InSAR-PIM (referred as to InSAR-GPIM). The InSAR-GPIM was tested in the Qianyingzi coal mining area, China. The results show that the InSAR-GPIM-predicted horizontal and vertical displacements caused by subcritical, critical, and supercritical extraction agree well with the in situ observations, with average root-mean-square errors of about 0.032 and 0.050 m, respectively. These accuracies represent improvements of 60.9% and 59% when compared with the accuracies predicted by the InSAR-PIM in the horizontal and vertical directions. The results indicate that the InSAR-GPIM is capable of accurately predicting 3-D mining-induced displacements under different extraction conditions (i.e., subcritical, critical, and supercritical extraction), and it performs much better than the InSAR-PIM in the case of subcritical extraction. It is therefore believed that InSAR-GPIM will have a wider scope of applications than the previous InSAR-PIM. [ABSTRACT FROM PUBLISHER]

Abstract: Downscaling of copper interconnects is demanding more knowledge about the microstructure and grain growth mechanisms in sub 100nm dimensions. Large grains are needed to reduce the resistivity and to increase the reliability of narrow lines. Plating additives are used for a void free filling of the interconnecting vias and lines. Fractions of these additives are incorporated into the copper as impurities during electrochemical deposition. In the present paper the role of additive concentration on grain growth is investigated. Interconnect lines from 72nm to 1.9μm line width were completely filled with copper using different additive concentrations in the electrolyte. The impurity level was measured by time of flight secondary ion mass spectrometry. The samples were stored at room-temperature to achieve self-annealing or tempered at low and high temperatures. Self-annealing slows down with increasing additive concentration whereas bamboo-like grains are present after annealing all samples at high temperatures. Grain growth was studied as well as the average grain size, resistivity, and {111} texture. [Copyright &y& Elsevier]

Mining-related deformations are the direct cause for most of geohazards (e.g., landsides, building damage, and aquifer broken). Limited by available number of current space-borne SAR sensors and their near-polar flighting configuration, previous InSAR methods based on multi-track SAR datasets are hardly to performed to accurately retrieve mining-induced 3-D time-series displacements. This paper presents a method for retrieving mining-induced 3-D time-series displacements from single-track SAR datasets by fusing a mining-related prior deformation model. Compared with the previous multi-track SAR-based methods, the presented method has much less requirement on SAR data and can significantly improves the accuracy of estimated time-series deformations in the north direction. Finally, 13 ascending TerraSAR-X images over Yulin coal mining area, China, were selected to test the proposed method. [ABSTRACT FROM AUTHOR]