Experimental study on dust removal optimization of shearer external spray in air velocity.

In order to clarify the influence of air velocity on the atomization effect of shearer external spray and optimize dust suppression performance, the dust removal experiment was carried out by utilizing the self-designed external spray experiment platform. The effect of three kinds of air velocity on the atomization effect of main spray parameters was investigated to clarify the influence of air velocity on the atomization effect of shearer external spray and optimize dust suppression performance. The results showed that the influence of air velocity on droplet size and distribution width of the droplet size was slightly less than the spray pressure. The average diameter of the droplet was 54.211 µm, and the particle size distribution of the droplet was more uniform and concentrated when air velocity was 2 m/s, the pressure was 5 MPa and nozzle diameter was 1.0 mm. When the air velocity was less than 2 m/s and the spray pressure was 3-5 MPa, the atomization effect was better by using 1.0 or 1.2 mm diameter nozzle. Through on-site applications and optimization, the leeward total dust removal efficiency of the shearer can reach 79.43%, and the maximum increase range can reach 18.51 percentage points. The respiratory dust removal efficiency of the shearer can reach 87.45%, and the maximum increase range can reach 11.87 percentage points.

Applicability of accident analysis methods to Chinese construction accidents.

INTRODUCTION: It is necessary to clearly understand construction accidents for preventing a rise in Chinese construction accidents and deaths. Better analysis methods are required for Chinese construction sector accidents. METHODS: Choosing and analyzing a typical construction accident based on four popular contemporary accident causation models: STAMP, AcciMap, HFACS, and the 2-4 Model. Then we evaluated the models' applicability to construction accidents, including their usability, reliability, and validity. RESULTS: STAMP addressed how complexity within the accident system influenced the accident development, and its output makes the responsibilities clearer for the accident. AcciMap described the entire system's failure, the entire accident's trajectory, and the relationship between them. AcciMap showed that the accident was a dynamic developing process, and this method has a high usability. The taxonomic nature of HFACS is an important feature that provides it with a high reliability. In the accident reviewed here, we found that poor management was a critical factor rather than the individual factor in the accident. The 2-4 Model provided detailed causes of the accident and established the relationship among the accident causes, the safety management system, and the safety culture. It also avoided capturing all of the complexity in the large sociotechnical system and revealed a dynamic analysis and developing process. We confirmed that it has a high usability and validity. Therefore, the 2-4Model is recommended for future Chinese construction accident analysis efforts. PRACTICAL APPLICATIONS: The study provides a useful, reliable, and effective analysis method for Chinese construction accidents.

The Safety Attitudes of Senior Managers in the Chinese Coal Industry.

Introduction: Senior managers' attitudes towards safety are very important regarding the safety practices in an organization. The study is to describe the current situation of senior managers' attitudes towards safety in the Chinese coal industry. Method: We evaluated the changing trends as well as the reasons for these changes in the Chinese coal industry in 2009 and in 2014 with 168 senior manager samples from large Chinese state-owned coal enterprises. Evaluations of 15 safety concepts were performed by means of a questionnaire. Results and Conclusions: Results indicate that, in 2014, three concepts were at a very high level (mean > 4.5), and six were at a relatively high level (4.5 > mean > 4.0). Analyses of changing trends revealed that nine concepts improved significantly, while four greatly declined in 2014 compared to those in 2009. The data reported here suggest that the reasons for the significant improvement with respect to the nine concepts include the improvement in social and legal environments, the improvement of the culture of social safety, workers' safety demands being met, and scientific and technical advances in the coal industry. The decline of the four concepts seemed to be caused by a poor awareness of managers in the coal industry that safety creates economic benefits, insufficient information on safety, inadequate attention to the development of a safety culture and safety management methods, and safety organizations and workers' unions not playing their role effectively. Practical Applications: We therefore recommend strengthening the evidence that safety creates economic benefits, providing incentives for employees to encourage their participation in safety management, and paying more attention to the prevention of accidents in coal mines via safety organizations and unions. These results can provide guidelines for workers, industrialists, and government regarding occupational safety in the whole coal industry.