Anti-interference and non-destructive identification of textile fabrics using front-face excitation-emission matrix fluorescence spectroscopy combined with multi-way chemometrics.

The identification of trace textile fabrics discovered at crime scenes plays a crucial role in the case of forensic investigations. Additionally, in practical situations, fabrics may be contaminated, making identification more challenging. To address the aforementioned issue and promote the application of fabrics identification in forensic analysis, front-face excitation-emission matrix (FF-EEM) fluorescence spectra coupled with multi-way chemometric methods were proposed for the interference-free and non-destructive identification of textile fabrics. Common commercial dyes in the same color range under different materials (cotton, acrylic, and polyester) that cannot be visually distinguished were investigated, and several binary classification models for the identification of dye were established using partial least squares discriminant analysis (PLS-DA). The identification of dyed fabrics in the presence of fluorescent interference was also taken into consideration. In each kind of pattern recognition model mentioned above, the classification accuracy (ACC) of the prediction set was 100%. The alternating trilinear decomposition (ATLD) algorithm was executed to separate mathematically and remove the interference, and the classification model based on the reconstructed spectra attained an accuracy of 100%. These findings indicate that FF-EEM technology combined with multi-way chemometric methods has broad prospects for forensic trace textile fabric identification, especially in the presence of interference.

Numerical simulation study of strip filling for water-preserved coal mining.

The Jurassic coalfield in northern Shaanxi, China is one of the seven largest coalfields in the world. It is located in an arid region of northwestern China, with poor water resources and fragile ecological environment. Due to coal mining, the rock layers on the coal seam will be slumped and fractured to produce fissures. The penetrated fissures will cause a mine water burst disaster and cause damage to groundwater and surface water. The strip filling method can control the expansion of the diversion fissure zone and protect the groundwater and surface water from the underground mining of coal. In this paper, the effects of different strip filling conditions on the diversion fissure zone are studied by discrete element numerical experiments. The study indicates that the upward-fissure and the downward-fissure penetrations are the direct causes of the instability of the water-blocking rock group. After the upward fissure extends to a certain extent, there will be a downward fissure. Under the condition of controlling the width of the filling strip and the compressive strength, the strip filling method can effectively prevent the upward and downward fissures of the water-blocking rock group from penetrating and can ensure that the surface water system is not affected by the underground coal mining activities.