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In order to ensure the safe and rapid emission of high concentration gas when the mine opens the closed roadway, the gas emission method of the measure hole on the closed wall of the roadway and the extraction hole through the head of the roadway are studied. It solved the problems of difficult control of air volume, long gas emission time, easy overrun of return air flow gas concentration and large influence range in closed roadway gas emission. The practical results show that after the closed wall of -580 m track stone gate roadway is opened, the gas concentration in the airflow is 0.18 %, and the gas emission time is 2 min, which greatly shortens the gas emission time. There is no abnormal phenomenon in the segmented gas emission, and the safe gas emission is realized.

Hydrocarbon reservoirs with a large column height as well as tight gas rocks require a large range of capillary pressures to describe the saturation of fluids present in these formations. While mercury injection capillary pressure (MICP) can achieve high equivalent capillary pressures, the tests are destructive to the core plugs. Centrifuge techniques have gained in popularity since they are faster than the porous plate technique, but they are limited in the achievable pressure range. Here, we propose the use of fluorinated oils to extend the achievable capillary pressure of the air-brine centrifuge technique by a factor of two. We use Fluorinert FC-70 in an inverted bucket configuration which doubles the radius of rotation and keeps the density contrast comparable to an air-brine system. Furthermore, we show the application to NMR T2 cut-off determination as a function of capillary pressure. Since Fluorinert does not contain any hydrogen, there is no signal overlapping with the brine in the core plugs. Furthermore, in the inverted bucket configuration, the outlet face of the plug is not in contact with a drainage surface so that the Hassler-Brunner boundary condition of Pc = 0 is satisfied. Additionally, the method allows the storage under a liquid Fluorinert phase, which prevents evaporation and significantly extends the available time for NMR measurements at low water saturations.

GIS is prone to various defects and faults after putting into operation, and the failure rate is high. At present, the inspection methods of GIS in operation include traditional inspection mode, two-dimensional code inspection mode, radio frequency identification technology mode and robot inspection mode. However, the current inspection robot has the disadvantages of weak adaptability to complex environment, insufficient inspection scope, low efficiency and low intelligence. Therefore, this paper designs a GIS monitoring system based on the rail robot. By installing all kinds of sensors on the rail robot, with the help of binocular vision and mechanical arm, the omni-directional live detection of GIS in transit can be realized.

In a hot and dry climate, the design and construction of buildings involve the adoption of combination between shape of building envelope and construction materials. The objective of this work is to study the thermal behavior of a multilayer wall submitted to varying climatic conditions. We have proposed four configurations of an element of an outer wall. A numerical simulation was used to understand the phenomenon of thermal inertia, especially its influence on the resulting temperatures. The study is based on the modeling of heat transfer in a 2D unsteady-state using a computational fluid dynamics (CFD) code. The comparison of numerical results was affected with an available experimental data and shows a satisfactory agreement. In addition, this work highlights the importance of the study of the thermal inertia of the wall in order to ensure a comfortable indoor climate of building located in hot and dry climate.

The medium voltage direct hanging energy storage system has been widely used in high capacity applications, which gets rid of power frequency transformer and is of high conversion efficiency. This paper introduces the medium voltage direct hanging energy storage system topology scheme. In order to improve the battery life and capacity utilization, the in-phase and inter-phase battery equalization control strategies are studied. Finally, the simulation results on medium voltage direct hanging energy storage system prove the correctness and effectiveness of the equalization control strategy.

The structure and form of modern power grids are becoming more and more complex, and there are many indicators and factors that need to be considered to evaluate the development status of the power grid. In order to diagnose the development level of power grid, the index system is reconstructed, which includes seven dimensions: the coordination of power grid development speed, the coordination of power grid development scale, the coordination of power grid structure, the security and reliability of power grid, the level of equipment, the utilization efficiency of power grid and the development benefit of power grid, the construction principle and index selection basis are given. When dealing with contradictory problems in reality, methods combining quantitative and qualitative can be applied to study. The matter element analysis method is applied to power grid development diagnosis, and a model of power grid development diagnosis based on matter element analysis is established, the model can not only diagnose the development level of power grid, but also determine the key factors that affect the diagnosis results, and give suggestions for improvement. The practical example verifies the feasibility and rationality of the method, which has good evaluation accuracy and prediction effect.

A numerical study of heat and mass transfer characteristics of a two-inlet PV/T air collector is performed. The influence of thermal characteristics and efficiency is investigated as the area ratios of inlet and outlet of the single channel with two inlets are changed. The design of the two-inlet PV/T air collector can avoid the poor heat transfer conditions of the single inlet PV/T air collector and improve the total photo-thermal efficiency. When the inlet/outlet cross-sectional area ratio is reduced, the inlet air from the second inlet enhances the convection heat transfer in the second duct and the temperature distribution is more uniform. As the cross-sectional area of the second inlet increase, the maximum heat exchange amount of the two-inlet PV/T air collector occurs between the inlet and outlet cross-sectional area ratio L=0.645 and L=0.562.

Reservoir siting, permitting, construction and operation can, at times, face insurmountable challenges. Mosul Dam, a multipurpose dam located in Northern Iraq, is constructed on a dissolvable anhydrite, gypsum and limestone formation. To mitigate long-term impacts to the foundation, the dam designers opted for a structural solution. They incorporated into the design a grouting gallery for long-term maintenance grouting of the foundation cutoff grout curtain. In 2016, concerns with the risk posed by the deteriorating foundation resulted in the execution of the Mosul Dam emergency grouting and maintenance project. This paper illustrates how the international community proactively came together to prevent an incident of potential tragic proportions well before it could manifest itself. The emergency grouting work is an excellent example of Governments investing in preventing a disaster rather than investing in fixing a disaster. The paper presents the general approach adopted for the execution of the emergency project and discusses how the scope of work (SOW) evolved to address the myriad of requirements, including the training and transfer of information and equipment to the Iraqi Ministry of Water Resources that could not have been foreseen during the scoping of the work. Additionally, this paper illustrates the success that can be achieved when team members share a strong commitment to cooperation and a determination to succeed.