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The mine ventilation system is an indispensable component to improve coal mining efficiency and ensure the safety of production. Only by clearly grasping the comprehensive evaluation quality of the ventilation system can effective countermeasures be formulated. This paper establishes an evaluation index system for mine ventilation systems by combining a qualitative survey with quantitative research. Specifically, the primary indicators are screened through R-type clustering and the coefficient of variation method. The weight of each index is determined by the entropy weight method. Moreover, the technique for order preference by similarity to ideal solution (TOPSIS) method is used to evaluate the quality of the mine ventilation system. Finally, this evaluation system is used to evaluate the ventilation renovation project in the production mining area of the Sihe mine. The evaluation results verify the effectiveness of the establishment of the mine ventilation evaluation index system and of the evaluation methods.

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Background. The efficacy of robotic-assisted gait training (RAGT) should be considered versatilely; among which, gait assessment is one of the most important measures; observational gait assessment is the most commonly used method in clinical practice, but it has certain limitations due to the deviation of subjectivity; instrumental assessments such as three-dimensional gait analysis (3DGA) and surface electromyography (sEMG) can be used to obtain gait data and muscle activation during walking in stroke patients with hemiplegia, so as to better evaluate the rehabilitation effect of RAGT. Objective. This single-blind randomized controlled trial is aimed at analyzing the impact of RAGT on the 3DGA parameters and muscle activation in patients with subacute stroke and evaluating the clinical effect of improving walking function of RAGT. Methods. This randomized controlled trial evaluated the improvement of 4-week RAGT on patients with subacute stroke by 3DGA and surface electromyography (sEMG), combined with clinical scales: experimental group ( n = 18 , 20 sessions of RAGT) or control group ( n = 16 , 20 sessions of conventional gait training). Gait performance was evaluated by the 3DGA, and clinical evaluations based on Fugl-Meyer assessment for lower extremity (FMA-LE), functional ambulation category (FAC), and 6-minute walk test (6MWT) were used. Of these patients, 30 patients underwent sEMG measurement synchronized with 3DGA; the cocontraction index in swing phase of the knee and ankle of the affected side was calculated. Results. After 4 weeks of intervention, intragroup comparison showed that walking speed, temporal symmetry, bilateral stride length, range of motion (ROM) of the bilateral hip, flexion angle of the affected knee, ROM of the affected ankle, FMA-LE, FAC, and 6MWT in the experimental group were significantly improved ( p < 0.05 ), and in the control group, significant improvements were observed in walking speed, temporal symmetry, stride length of the affected side, ROM of the affected hip, FMA-LE, FAC, and 6MWT ( p < 0.05 ). Intergroup comparison showed that the experimental group significantly outperformed the control group in walking speed, temporal symmetry of the spatiotemporal parameters, ROM of the affected hip and peak flexion of the knee in the kinematic parameters, and the FMA-LE and FAC in the clinical scale ( p < 0.05 ). In patients evaluated by sEMG, the experimental group showed a noticeable improvement in the cocontraction index of the knee ( p = 0.042 ), while no significant improvement was observed in the control group ( p = 0.196 ), and the experimental group was better than the control group ( p = 0.020 ). No noticeable changes were observed in the cocontraction index of the ankle in both groups ( p > 0.05 ). Conclusions. Compared with conventional gait training, RAGT successfully improved part of the spatiotemporal parameters of patients and optimized the motion of the affected lower limb joints and muscle activation patterns during walking, which is crucial for further rehabilitation of walking ability in patients with subacute stroke. This trial is registered with ChiCTR2200066402.

The air curtain dust control device (ACDCD) utilizes the air curtain formed by high-speed gas ejected from an injection cavity to separate the driver working area from the roadheader pollution area, so as to achieve the purpose of dust control. The existing ACDCDs are customized for various roadheaders and various production conditions, which are not flexible enough and are difficult to industrialize. Meanwhile, the existing ACDCD has drawbacks such as its costly maintenance, difficulty in replacement of the core parts, and costly iterative design of products. Due to the growing resource demand and sustainable development needs, the ACDCD should be designed considering the full life cycle technology of the product. In this paper, we proposed a modular method of the ACDCD based on improved spectral cluster module division and proposed an improved air curtain dust control device (IACDCD). Specifically, a similarity matrix construction method considering the functional and structural correlation matrix of components was proposed to strengthen the connection relationship of components. Two existing ACDCDs and the IACDCD were modularized using the improved spectral cluster module division method. The results showed that the improved spectral clustering module division method could effectively improve the clustering effect. The results of the module division of the three ACDCDs proved that the IACDCD could effectively increase the replaceability and maintenance of the injection cavity, and then reduce the maintenance cost and iterative design cost of the ACDCD.