Microwave technology is a promising rock-breaking method because of its high efficiency and lack of secondary pollution (Wei et al., 2019; Zheng et al., 2016). This technology has been considered widely by scholars, and systematic research work has been conducted on the fracture weakening and fracture characteristics of typical hard rock in …

Rock mechanical properties normally refer to strength (uniaxial compressive strength, UCS), deformation (Young's modulus and Poisson's ratio, assuming that the rock mass is an isotropic linear ...

Microwave technology is a promising rock-breaking method because of its high efficiency and lack of secondary pollution (Wei et al., 2019; Zheng et al., 2016). …

The torque of the shield cutter head consists of the following nine parts [24,32, 33]: Due to the correlation between mud cake cleaning amount and time, after considering the time factor, the ...

This speaker is the best balance of great performance and affordability and is one of the best high-efficiency speakers for tube amps. 3. KLIPSCH RB-81 II. Speaker Size: 8 inches | Speaker weight: 27.6 pounds | Dimension: 19 x 9.23 x 12.3 | Frequency Response: 44Hz-24kHz | Speaker Type: Floor-standing, bookshelf.

This low, low priced speaker measures 11.8 inches high (299mm), and it has a 6.5-inch (165mm) polypropylene woofer that's a good deal larger than what you'll find in most budget speakers.

First, set the thermostat to call for heat. At the furnace, disconnect the power leads attached to the pressure switch terminals. Set the multimeter to ohms (resistance test), then place each multimeter lead …

PDF | High-efficiency rock breaking by hydraulic jetting is the key to radial horizontal drilling technology. In order to improve the drilling... | Find, read and cite all the …

The roughened rock surfaces and high velocity jet impact can promote the thermal shock effects of LN 2, therefore enhancing the rock breaking ability. The tensile stress induced by LN 2 cooling can reach tens of MPa, much higher than rock strength. LN 2 jet is an efficient way to break coal rock and high-temperature rock. It can realize the ...

A notable fact is that the energy efficiency of conventional milling is only about 1%, as mentioned in Sect. 1. An earlier experimental study indicated that about 80–90% of the energy input of a ball mill was used in heating the material (Schellinger 1951, 1952), and a recent study showed that over 75% of the electrical energy was used to …

(b) Low drilling efficiency in high-temperature hard rocks seriously restricts the project's economic feasibility and prolongs the construction period. For instance, the conventional rotary mechanical bit is severely worn out during high-temperature hard rock drilling, resulting in low rock crushing efficiency [[10], [11], [12]]. In addition ...

As the exploration and drilling of oil, natural gas and geothermal wells are expanding continuously, research into high-efficiency rock drilling technology is imperative. High-voltage electro pulse boring (EPB) has the advantages of high rock breaking efficiency and good wall quality, and is a new and efficient potential method of rock …

Various studies on the energy transfer efficiency and rock breaking mechanism of percussive drilling have been carried out. Wu et al. ... Compared with normal temperature, the rock at high temperature is more prone to tensile cracks under percussion. Download : Download high-res image (534KB) Download : Download full-size image; …

Abstract. High-efficiency rock breaking by hydraulic jetting is the key to radial horizontal drilling technology. In order to improve the drilling efficiency of hydraulic jet rock …

More prominently, the maximum fracture width of coal, sandstone, shale and granite were 89.17 µm, 1.29 µm, 0.028 µm and 2.12 µm when the temperature difference between LN2 and rock samples were 296 °C. LN2 is shown to exhibit superior fracturing efficiency on coal and granite, characterized by complex fracture networks with …

In order to achieve high efficiency of rock breaking and low wear of cutter buttons, the time of cutter buttons in contact with rocks should be 0.02–0.03 s, and correspondingly the linear velocity (V c) of side cutters should be controlled at 0.7–1.0 m/s.

Research shows that among many new rock-breaking methods, the most potentially efficient and easy-to-implement rock-breaking method is the high-pressure water jet rock-breaking technology, which has great potential for development and research value. 2 In recent decades, high-pressure water jet rock-breaking technology has …

Research on High-Efficiency Rock Fragmentation of TBM Cutter-Head Conference: 3rd International Conference on Civil Engineering, Architecture and Volume: …

Given the fact that the granite rock stove depicts a relatively high thermal efficiency (28.8%) and fuel use reduction (78.8%) (Table 4), there is a higher likelihood for it to operate under reduced cost, making it cheaper than the conventional stoves. 4. Conclusions

High-efficiency rock breaking by hydraulic jetting is the key to radial horizontal drilling technology. In order to improve the drilling efficiency of hydraulic jet rock breaking in radial horizontal wells, based on LS-Dyna display dynamics, a numerical simulation model of single-nozzle jet rock breaking was established to analyze the …

Hence, the denitrification efficiency is greater than 90%, when the molar ratio of O 3 to NO is 0.15. Further, the possible reaction pathway for the oxidative removal of NO is proposed. Besides, magnesium calcium carbonate and calcium fluorophosphate, the main components of phosphate rock, play a crucial role in the efficient removal of NO x.

However, high-temperature rock has different mechanical properties than room-temperature rock. Rock temperature may have influence on the percussive process of the axial-torsional coupled percussive drilling. In this section, the effects of rock temperature on the energy transfer efficiency and rock damage were analyzed.

It is an ideal safe and efficient rock breaking and steerable drilling technology. Taking the horizontal well as an example, the horizontal section is generally up to thousands of meters or even longer, so it is difficult to drill the whole horizontal section with only "one trip". ... High-efficiency PDC bit, steering BHA, drilling fluid ...

The results can provide reference value for dynamic issues such as high-efficiency rock breaking, prevention of rock burst, and surrounding rock support in deep rock masses. 1. Introduction. Bedding is the main manifestations of metamorphic rocks and sedimentary rocks [1 ...

High-efficiency rock breaking by hydraulic jetting is the key to radial horizontal drilling technology. In order to improve the drilling efficiency of hydraulic jet rock breaking in radial horizontal wells, based on LS-Dyna display dynamics, a numerical simulation model of single-nozzle jet rock breaking was established to analyze the influence ...

The Maxeon 6 panel has an efficiency rating of 22.8% and manages a below-average loss of efficiency to high temperatures and a low degradation rate—just 8% over 25 years and 11.75% over 40 years. With that being said, the National Renewable Energy Laboratory (NREL) has produced solar modules that, in laboratory conditions, …

Wharfedale Linton. The best of old hi-fi combined with the best of the new. If you want a new speaker that's built using modern methods and materials, but that takes an old-school approach to styling and sound, then you might well want the new version of the Linton, launched to celebrate Wharfedale's 80th anniversary.

YHC High Efficiency Gas Heat Unit March 2020 RT-PRC074E-EN. Table 3. Unit MCA & MOP electrical data (standard indoor fan motor) (cooling or gas (a) (a)For MCA/MOP of units with electric heat, refer to product catalog.) T/YHC Volts MCA MOP 036 208-230/1 28.3 45 036 208-230/3 21.0 30 036 460/3 12.0 15

High-power laser has been considered as a potential method of rock breakage through melting. However, high energy consumption and low efficiency are the main restrictions for applying laser technology in rock excavation and fragmentation. A new rock breakage method which combines pulsed laser and induced cavitation is described …