Research on evaluation technology system of mid-deep underground coal gasification based on researchers from China.

Underground coal gasification is of great strategic significance to the effective and clean development of coal resources and scale up production of natural gas worldwide. Selection evaluation is the foundation of the exploration and development of underground coal gasification. In this paper, the differences between mid-deep (500-2200 m) and shallow layer (<500 m) underground coal gasification are analyzed, the key parameters affecting underground coal gasification are clearly identified, and the selection evaluation technology system is established. The results show that there are great differences between mid-deep and shallow layer underground coal gasification in terms of furnace construction site selection, engineering process, gasification efficiency and gasification products, the former is the main development direction in the future considering the resource potential, gasification efficiency, environmental protection and technological progress. The research of mid-deep underground coal gasification selecting should be carried out step by step with "favorable area-favorable zone-favorable zone ranking-favorable target" evaluation system. In the early stage of exploration, the product of thickness and volatiles can be used as a rapid evaluation index. Within the suitable range, the larger the index is, the more favorable it is, and when the index is greater than 3, it is defined as the favorable area. Further, ten key geological parameters of coal seam geological conditions, coal-rock and coal-quality characteristics and structural hydrologic conditions are selected and graded during zone evaluation according to different threshold ranges. At the same time, a favorable zone queuing method based on the two-factor evaluation method is established. Additionally, the final target site selection is established with more detailed evaluation parameters, such as process performance parameters, gasification characteristics parameters, technical recoverable indicators, economic recoverable indicators. The study provides the siting selection technology for the middle deep coal underground gasification, which is of great significant for the development of coal underground gasification industry.

An Efficient Improved Harris Hawks Optimizer and Its Application to Form Deviation-Zone Evaluation.

Evaluation of the deviation zone based on discrete measured points is crucial for quality control in manufacturing and metrology. However, deviation-zone evaluation is a highly nonlinear problem that is difficult to solve using traditional numerical optimization methods. Swarm intelligence has many advantages in solving this problem: it produces gradient-free, high-quality solutions and is characterized by its ease of implementation. Therefore, this study applies an improved Harris hawks algorithm (HHO) to tackle the problem. The average fitness is applied to replace the random operator in the exploration phase to solve the problem of conflicting exploration strategies due to randomness. In addition, the salp swarm algorithm (SSA) with a nonlinear inertia weight is embedded into the HHO, such that the superior explorative ability of SSA can fill the gap in the exploration of HHO. Finally, the optimal solution is greedily selected between SSA-based individuals and HHO-based individuals. The effectiveness of the proposed improved HHO optimizer is checked through a comparison with other swarm intelligence methods in typical benchmark problems. Moreover, the experimental results of form deviation-zone evaluation on primitive geometries show that the improved method can accurately solve various form deviations, providing an effective general solution for primitive geometries in the manufacturing and metrology fields.

An unusual case of a penetrating neck injury (PNI) illustrating the use of a "no zone" approach for the management of this injury and a review of the literature.

We present an unusual case of a young male with a penetrating neck injury (PNI) due to a work-related injury. A metallic foreign body traversed from entry at surgical Zone 2 to Zone 1 in the neck and resulted in a transection of the left thyrocervical trunk at the origin with the left subclavian artery. Computed Tomographic Angiography (CTA) of the aortic arch and major branch vessels demonstrated haemorrhage anterior to the left subclavian artery and left thyrocervical trunk. We describe some of the diagnostic and operative challenges which may occur in these rare and life-threatening injuries. We have also reviewed some of the recent key literature on this topic and have collated the recommendations of the review. In recent years, there has been a movement away from selective "zone-based" mandatory surgical exploration for Zone 2 injuries, as well as invasive and time-consuming investigations (such as digital subtraction angiography, contrast oesophageal swallow and bronchoscopy) for Zone 1 and 3 injuries due to the high number of negative surgical procedures and investigations. We demonstrate there is now an evidence-based algorithm which demonstrates that a "no zone" approach to the management of these patients is safe and effective. This requires an initial physical examination looking for the presence or absence of "hard", "soft" or "no" physical signs in these patients, and then deciding on subsequent management which would include immediate surgery, CTA of the aortic arch and branches (and subsequent surgical or other management) or observation only. Our aim in describing this case it to highlight that there is now good evidence-based guidance for the safe and effective management of patients with this infrequent but potentially fatal injury.