The investigation described here was conducted to clarify the corrosion behaviour of high level radioactive waste containers made of copper. The influences of oxygen, chloride ion and sulphate ion on copper crevice corrosion were studied in solutions simulating groundwater characteristic of northwest China. The results showed that oxygen, chloride ion and sulphate ion promote crevice corrosion. Chloride ion was found to play a significant role in the crevice corrosion mechanism in copper, but sulphate ion had no effect on the mechanism.

Crevice corrosion

10.1179/1743278215y.0000000026

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Effect of Compressed Gas on Deep Mine Long‐Distance Backfill Pipe Flushing: From Laboratory to Industrial Tests

Advances in Civil Engineering (2024)

Longjian Bai Hongjiang Wang Aixiang Wu Hao Li Shengkai Wang

The clean filling pipe can ensure sufficient overflow section, reduce paste transport resistance, and avoid slurry deposition. The introduction of compressed gas into the pipe flushing can improve the flushing effect and efficiency of the pipe and reduce water consumption. However, the dominant factors influencing water consumption water consumption are not well understood. The purpose of this study is to determine the effect of flow velocity, backfill gradient (4–7), gas void fraction (0–1), and gas pressure (0–0.7 MPa) on water consumption. Water consumption was obtained experimentally by modeling the gas–water flushing pipe. The criterion for the completion of pipeline cleaning is to reduce the water solid content of the flushing pipeline from the initial value to 1%. A model was established to predict water consumption, which was validated by industrial tests. The results show that the water consumption of the flushing pipe increased with the power law as the backfill gradient increased and decreased with the increase of gas void fraction, gas pressure, and flow velocity. The water consumption is 0.8–1.1 times the volume of the pipe in water flushing. However, the water consumption of gas–water flushing is 0.60–0.75 times the volume of the pipe. Gas–water flushing can reduce water consumption by up to 30%. The findings are conducive to design pipe flushing parameters to avoid excessive water consumption.

Flushing

Compressed air

10.1155/2024/6211202

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Deformation Characteristics and Energy Evolution Rules of Siltstone under Stepwise Cyclic Loading and Unloading

Buildings (2024)

Shengjun Miao Xiangfan Shang Hui Wang Mingchun Liang Pengjin Yang

Uniaxial step cyclic loading and unloading tests on siltstone were conducted to investigate the mechanisms and evolution characteristics of rock deformation, including elastic, viscoelastic, and plastic aspects. This study proposes a method for separating dissipated energy into damage energy, which is used for particle slippage and structural fractures, and plastic energy, which remains in cracks that do not open after unloading. Additionally, elastic energy is divided into particle elastic energy, released by particle rebound, and crack elastic energy, released by the reopening of compacted cracks. The results indicate that as the stress amplitude increases, the damage energy consumption, plastic energy consumption, particle elastic energy, and crack elastic energy increase. At peak stress, significant expansion and penetration of cracks within the rock sample occur, leading to a sharp increase in damage energy consumption and a dramatic decrease in the rock sample’s mechanical properties, with the particle elastic energy dropping quickly. Plastic energy dissipation relates solely to cracks that do not reopen during unloading, with minimal change after reaching peak stress. The calculated damage variables, based on damage energy consumption, align with the deformation and energy characteristics of the rock, providing a reasonable description of the damage development process of the rock under cyclic loading and unloading.

Siltstone

10.3390/buildings14061500

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Multiple recognition-powered abiotic bimetallic oxide nanozyme-based colorimetric platform for the selective detection of allergen β-lactoglobulin

Food Chemistry (2024)

C. Liu Linhui Liang Yang Yu Yang Hou Mao‐Sen Yuan

Bimetallic strip

10.1016/j.foodchem.2024.142400

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New Model and Finite Element Analysis of the Anti-Extrusion Strength of Backfill Drilling Pipelines

Minerals (2024)

Hao Li Hongjiang Wang C. Liu

Currently, in some domestic and foreign mines, the backfill drilling pipeline experiences a rupture phenomenon even when the wear degree is low. This results in a delay in production due to the filling becoming ‘sick’. This paper presents, for the first time, the damage mechanism from a mechanical perspective and re-derives the anti-extrusion strength model of the backfill drilling pipeline. We investigate the influence of the law on the anti-extrusion strength of pipelines from the perspective of strata and cement rings. We then verify the theoretical and simulation results through engineering examples. The results demonstrate that the Mises stress criterion is a suitable modification principle for the anti-extrusion strength model of the backfill drilling pipeline. The anti-extrusion strength of the pipeline is related to the elastic modulus and Poisson’s ratio of the stratum, and the thickness of the cement ring. It is negatively affected by the depth of the stratum. For hard strata, a cement ring with a smaller elastic modulus is suitable, while for soft stratum, a cement ring with a larger elastic modulus is recommended. When the missing angle of the cement ring is less than 60°, the stress concentration factor increases up to 2.2. The stress unloading capacity of the cement ring ranges from 32.7% to 37.8%, and optimal performance of the cement ring is achieved when it has high strength and low rigidity. The backfill filling pipeline of a copper mine abroad was destroyed due to external extrusion force exceeding its anti-extrusion strength value. The modified pipeline anti-extrusion strength model is 18.2% higher than the pipeline API strength value. This finding can inform the design of the backfill filling pipeline for China’s kilometer-deep wells in the future.

10.3390/min14040365

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