Structural failure process of schistosity rock under microwave radiation at high temperatures

The effects of high temperature induced by microwave radiation on the schistosity structural rock were investigated. A 1.45 kW commercial microwave system was employed to irradiate specimens to a designed temperature (300–800 °C) for 15 minutes. Cracking and local melting initially appeared in the biotite enrichment area at 500 °C. Macro-cracks in the dark area were parallel to the schistosity trend, owing to the weak connection in a direction perpendicular to the schistosity plane. The composition of the rock did not significantly change before and after microwave radiation. The diffraction peak intensity of the biotite decreased with temperature increase, owing to melting. The average peak stress decreased significantly with increasing temperature. It is concluded that the high temperature induced by microwave radiation promotes hard rock breakage and the schistosity structure of rock significantly affects the cracking pattern

The thermal damaging process of diorite under microwave irradiation

Laboratory tests have been conducted to investigate the effects of thermal damage on diorite under microwave irradiation. The sample rocks were heated to high temperature range of 300 to 800 ℃ in a single-mode microwave furnace. The experimental results show that the rocks started to crack at 500 ℃ and completely disintegrated at 700 ℃. The intensities of quartz diffraction peaks were almost unchanged while the diffraction peak intensity of hornblende gradually decreased with temperature increasing. In addition, the chlorite diffraction peak disappeared at 500 ℃. The compressive strength of the sample decreased to 40% at 600 ℃ and it approached zero at 700 ℃. In this paper, the possible reasons for the thermal effects on the fracture of diorite were discussed, which can be related to water evaporation, thermal cracks and mismatch thermal expansion, and phase transition on quartz. The result indicates that diorite can be effectively destroyed under microwave irradiation

Comparative study on the deterioration of granite under microwave irradiation and resistance-heating treatment

To investigate the deterioration of granite under microwave irradiation and heat transfer, granite specimens were heated up to 400-1000 °C and then kept for 15 min. Uniaxial compressive strength testing results demonstrate a similar variation in two groups in 400-900 °C, which is initial strengthening (less than 500 °C), subsequent weakening (500-600 °C) and final stabilizing (600-900 °C). Furthermore, the specimen irradiated by microwaves presented a second decline at 1000 °C. Compared to heat transfer, microwave irradiation can reduce the strengthening due to localized transition plasticity and further promotes the deterioration of rock structure in weakening stage. TG/DSC results indicate that the strengthening is related to the iron mineral transition. The formation of porous glass substance which is mainly composed of feldspar and biotite. Furthermore, temperature-controlled microwave irradiation induced the variation of feldspar crystallinities, which is consistent with the corresponding UCS data, especially the plagioclase. In practical application, microwaves can be used to irradiate the vulnerable positions (surface edge and cleavage) and kept the whole rock mass around 600 °C

A Study on Transportation Carbon Emissions Based on the IPCC Method: a Case Study of Chongqing City

The carbon emissions from transportation have an undeniable impact on global climate change. This article focuses on the central urban area of Chongqing City as the research area and uses IPCC's reference method to calculate the carbon emissions from transportation in Chongqing from 2016 to 2020. The study estimated the carbon emissions from transportation vehicles in terms of fossil fuels and electricity, and analyzed the relationship between the carbon emissions of transportation vehicles powered by fossil fuels and electricity respectively. The study found that the carbon emissions from transportation in Chongqing increased during the study period, with gasoline and diesel vehicles accounting for the majority of emissions. In addition, this article also analyzed the role of promoting electric vehicles and achieving electrified transportation in reducing carbon emissions from transportation vehicles, which was found to be an effective way. Therefore, this article suggests that efforts should be made to promote and develop electric vehicles, while encouraging and promoting the achievement of electrified transportation to achieve the goal of reducing carbon emissions from transportation vehicles

Structural evolution of kaolinite in muddy intercalation under microwave heating

The failure of muddy intercalation in the slope is mainly due to the clay minerals which mainly contains the kaolinite. This study investigates the structural evolution of kaolinite in muddy intercalation exposed to the microwave heating of 300 °C–800 °C by evaluating the uniaxial compressive strength, morphology, mineralogical composition, and water stability. Results show that the crystal structural evolution of kaolinite can be divided into four stages, which are 300 °C–400 °C, 400 °C–500 °C, 500 °C–700 °C, and 700 °C–800 °C. The kaolinite undertakes the thermal expansion, dehydroxylation-induced crack, kaolinite-metakaolinite transition, and two-step transition of metakaolinite - silica spinel ( γ -alumina) - mullite. The mechanical performance increasing consists of three stages. At 300 °C–400 °C, the uniaxial compressive strength increases about 38.7% due to thermal expansion. At 400 °C–700 °C, the uniaxial compressive strength is unchanged due to the balance between the positive side due to thermal expansion and semi-liquid metakaolinite and the negative side due to the dehydroxylation-induced crack propagation. At 700 °C–800 °C, the re-increase of 35.8% is mainly due to the two-step transition of metakaolinite-silica spinel ( γ -alumina)-mullite. Water leaching test shows that the kaolinite over 500 °C present well integrity