Results 61 to 70 of about 140,868 (311)

On the puzzling feature of the silence of precursory electromagnetic emissions [PDF]

, 2013
It has been suggested that fracture-induced MHz-kHz electromagnetic (EM) emissions, which emerge from a few days up to a few hours before the main seismic shock occurrence permit a real-time monitoring of the damage process during the last stages of ...
Chelidze, T., Eftaxias, K., Potirakis, S. M.   +2 more
core   +2 more sources

Using a high-pressure water jet-assisted tunnel boring machine to break rock

Advances in Mechanical Engineering, 2020
The concept of tunnel boring machine (TBM) disc cutter rock breaking coupled with high-pressure water jets has been proposed to overcome the difficulties that occur when TBMs encounter extremely hard rocks.
Jinliang Zhang, Yongchang Li, Yuansheng Zhang, Fengwei Yang, Chao Liang, Shunhui Tan   +5 more
doaj   +1 more source

Current challenges for preseismic electromagnetic emissions: shedding light from micro-scale plastic flow, granular packings, phase transitions and self-affinity notion of fracture process [PDF]

, 2013
Are there credible electromagnetic (EM) EQ precursors? This a question debated in the scientific community and there may be legitimate reasons for the critical views.
Eftaxias, K., Potirakis, S. M.
core   +2 more sources

Numerical Simulation Study on Characteristics of Tight Hard Sand Broken by Axe-shaped PDC Cutter

Shiyou jixie, 2021
The study on the specific rock breaking mechanism of axe-shaped PDC cutter in the existing literatures is relatively less, the rock breaking characteristic test data are mostly for field application data, and there is short of theoretical basis of tooth ...
Zhao Runqi, Chen Zhenliang, Shi Huaizhong, He Wenhao, Shi Xingxing, Chen Han   +5 more
doaj  

Heteroatom‐Engineering Promoted Co9S8 Bi‐functional Electrocatalyst for Hydrazine‐Assisted Hydrogen Production at Industrial Current Density

Advanced Functional Materials, EarlyView.
Fe and P co‐doped Co9S8 nanocorals (Fe, P‐Co9S8) are successfully synthesized by a heteroatom engineering strategy, which exhibit outstanding bifunctional electrocatalytic performance for both the hydrogen evolution reaction (HER) and hydrazine oxidation reaction (HzOR).
Yuying Meng, Chunyan Xiang, Wenbiao Zhang, Dahai Zeng, Bing Du, Bao Zhong, Yue Jiang, Damien Voiry, Qingsheng Gao   +8 more
wiley   +1 more source

Use of the energy of parametric oscillations to improve drilling indices [PDF]

, 2018
Purpose. Increase of the efficiency of using energy of parametric oscillations within the assembly of drilling string bottom by means of solving nonlinear-parametric equations of a “bit – drive motor – drilled-out rock” system to improve drilling indices.
Kovalchuk, Yu, Ohorodnikov, P, Svitlytskyi, V   +2 more
core   +2 more sources

Experimental Study on Rock Breaking Effect of Axe-Shaped and Triangular-Ridged Cutters Under Impact Load

Shiyou jixie
In drilling engineering， optimized cutter selection for specific formations is critical to enhance rock breaking efficiency. To this end， a Split Hopkinson Pressure Bar （SHPB） apparatus was used to conduct impact-induced rock breaking tests of triangular-
Li Yunzhu, Liu Ronghe, Du Jianhong, Liu Bin, Wang Wenwen, XI Yan, Zhang Tianze   +6 more
doaj   +1 more source

Theoretical and numerical studies of rock breaking mechanism by double disc cutters

International Journal of Mining Science and Technology, 2023
A plane mechanical model of rock breaking process by double disc cutter at the center of the cutterhead is established based on contact mechanics to analyze the stress evolution in the rock broken by cutters with different spacings.
Yiqiang Kang, Renshu Yang, Liyun Yang, Chengxiao Li, Jun Chen, Haonan Zhu, Ning Liu   +6 more
doaj   +1 more source

Universal Electronic‐Structure Relationship Governing Intrinsic Magnetic Properties in Permanent Magnets

Advanced Functional Materials, EarlyView.
Permanent magnets derive their extraordinary strength from deep, universal electronic‐structure principles that control magnetization, anisotropy, and intrinsic performance. This work uncovers those governing rules, examines modern modeling and AI‐driven discovery methods, identifies critical bottlenecks, and reveals electronic fingerprints shared ...
Prashant Singh
wiley   +1 more source

Aspects of energy requirements for rock drilling [PDF]

, 1974
Development of laboratory rock breakage techniques to relate energy and surface area produced by slow compression, drop hammer and stamp mill. A detailed study of laboratory rotary-percussive drilling in a wide range of rocks under different ...
Wootton, David
core