Research on Intelligent Monitoring and Protection Equipment of Vital Signs of Underground Personnel in Coal Mines: Review.

The coal industry is a high risk, high difficulty industry, and the annual global mine accident rate is high, so the safety of coal mine underground operations has been a concern. With the development of technology, the application of intelligent security technology in coal mine safety has broad prospects. In this paper, the research progress of vital signs monitoring and support equipment for underground personnel in coal mines is reviewed.

Noise-robust consistency regularization for semi-supervised semantic segmentation.

The essential of semi-supervised semantic segmentation (SSSS) is to learn more helpful information from unlabeled data, which can be achieved by assigning adequate quality pseudo-labels or managing noisy pseudo-labels during training. However, most relevant state-of-the-art (SOTA) methods are mainly devoted to improving one aspect. By revisiting the representative SSSS methods from a robust learning view, this paper discovers that the appropriate combination of multiple noise-robust methods contributes both to assigning sufficient quality pseudo labels and managing noisy labels.

Experimental and molecular dynamics study on combustion characteristics of non-stick coal.

To investigate the combustion characteristics of non-stick coal and the formation patterns of main combustion products and radicals, this study initially conducted a TG-DSC experiment of non-stick coal. Subsequently, non-stick coal was characterized and analyzed using XPS and C NMR experiments, and a molecular model with the formula CHONS was constructed. Subsequently, the ReaxFF MD method was employed to simulate the combustion molecular dynamics of the non-stick coal periodic mixing model under varying oxygen content and temperature conditions.

Influence of Tectonically Deformed Coal-Based Activated Carbon and Its Surface Modification on Methane Adsorption.

A series of coal-based activated carbons (CACs) were synthesized from mylonitized fat coal, a type of tectonically deformed coal (TDC) and symbiotic primary structural coal (PSC), followed by oxidative modification. The pore structure, surface oxygen-containing functional groups, and their influence on methane adsorption by CAC as the simplified coal model were investigated by using low-temperature nitrogen adsorption, Fourier transform infrared spectroscopy, Boehm titration, and X-ray photoelectron spectroscopy. The results showed that tectonic deformation fostered smaller pores, particularly ultramicropores in TDC, dominating methane adsorption.

Simulation Study of Coal Seam Gas Extraction Characteristics Based on Coal Permeability Evolution Model under Thermal Effect.

The permeability evolution law of high temperature and high stress coal seam is determined by the influence of multiphase coexistence and multifield coupling. In an environment greatly affected by disturbance and high temperature, the coal permeability model under the coupling of thermal and mechanical creep is not only a vital framework from which to examine gas migration law in multiphase and multifield coal seams but also an important theoretical foundation for gas control in coal seams. The influence of high-temperature environment on creep deformation and permeability is analyzed by several creep seepage tests under different temperature conditions.

Wearable Aerogels for Personal Thermal Management and Smart Devices.

Extreme climates have become frequent nowadays, causing increased heat stress in human daily life. Personal thermal management (PTM), a technology that controls the human body's microenvironment, has become a promising strategy to address heat stress. While effective in ordinary environments, traditional high-performance fibers, such as ultrafine, porous, highly thermally conductive, and phase change materials, fall short when dealing with harsh conditions or large temperature fluctuations.

The failure behavior of coal-rock combined body under compression-shear loading.

As shallow coal reserves continue to deplete rapidly, deep mining has become an unavoidable course of action. In the process of deep coal mining, affected by blasting, mining, and excavation, the coal-rock interface often encounters the action of compression-shear composite load. The interface crack directly affects the stability of the coal-rock structure.

Mechanical characteristics and energy evolution of rock with circular hole defects.

In this paper, the uniaxial compression damage characteristics of specimens are analyzed containing holes using PFC2D. In addition, the crack propagation, stress distribution and energy development characteristics of the specimens were systematically discussed. The findings indicate that the strength parameters of various specimens drop initially and then increase with increasing center point connecting angle, in comparison to intact rock.

A Multi-Target Localization and Vital Sign Detection Method Using Ultra-Wide Band Radar.

Life detection technology using ultra-wideband (UWB) radar is a non-contact, active detection technology, which can be used to search for survivors in disaster rescues. The existing multi-target detection method based on UWB radar echo signals has low accuracy and has difficulty extracting breathing and heartbeat information at the same time. Therefore, this paper proposes a new multi-target localization and vital sign detection method using ultra-wide band radar.

Research progress and visualization of underground coal fire detection methods.

Underground coal fires are a widespread disaster prevailing in major coal-producing countries globally, posing serious threats to the ecological environment and restricting the safe exploitation of coal mines. The accuracy of underground coal fire detection directly affects the effectiveness of fire control engineering. In this study, we searched 426 articles from the Web of Science database within 2002-2022 as the data foundation and visualized the research contents of the underground coal fire field using VOSviewer and CiteSpace.

Time-Frequency Characteristics and Evolution Law of Acoustic Emission Signals during the Deformation and Failure of Deformed Coal.

The research on the time-frequency characteristics and evolution law of acoustic emission (AE) signals during deformed coal failure is more conducive to understand the damage mechanism of coal. In this study, the experiments of AE monitoring during the intact and deformed coal failure were first conducted under loading axial stress and unloading confining stress conditions. Based on the evolution characteristics of volume strain and AE event rate, the damage process of coal was divided into three stages: nonfracture development stage, stable development stage of fracture, and unstable development stage of fracture.

Development of a biaxial apparatus for jamming profiles of photoelastic granular media.

We describe a two-dimensional biaxial apparatus that is used to conduct the experimental study of the jamming of granular media. The setup is designed based on the photoelastic imaging technique, which allows us to detect force-bearing contacts among particles, calculate the pressure on each particle according to the mean squared intensity gradient method, and compute contact forces on each particle [T. S.

A bankfull geometry dataset for major exorheic rivers on the Qinghai-Tibet Plateau.

Bankfull river discharge shapes river morphology. The bankfull river surface planform and river width can be used to quantify river size. Regional studies of stream ecology, hydrologic modelling, river carbon emissions and geomorphology from the perspective of fluvial processes are hindered by the lack of a highly accurate spatially distributed river network that considers bankfull river geometry.

Dynamic Effect of Shaped Charge Blasting and Its Application in Coal Seam Permeability Enhancement.

The dynamic effect of shaped charge blasting and its application in coal seam permeability enhancement have been investigated. Comparative experiments of shaped charge blasting and conventional blasting to fracture the concrete are carried out. Then, the propagation characteristics of explosion stress waves under shaped charge blasting and conventional blasting are analyzed by ANSYS/LS-DYNA.