https://doi.org/10.1089/ast.2019.2103 Antarctic subglacial lakes are often considered suitable analogues to extraterrestrial subglacial aqueous environments. Recently, an environmentally friendly RECoverable Autonomous Sonde (RECAS) was designed at the Polar Research Center of Jilin University (JLU) to sample the water of subglacial lakes without contamination. In this regard, the development of a fast-penetration thermal head is the key issue for RECAS. Two different prototypes were designed and tested at the JLU ice-well to determine the optimal design and operation parameters of the thermal heads. Practical top and bottom thermal heads were then designed based on one of the prototypes, which can penetrate ice at an average rate of 1.88 m/h. The test results for the RECAS thermal heads show that the rate of penetration (ROP) can be 1.80 -1.95 m/h in -10°C ice, and the axial load on the thermal head only affects the ROP when it is lower than a specified threshold. The decrease of the ice temperature from -10°C to -30°C leads to a decrease of 17% in the ROP. The bottom thermal head can drill into dirty ice, and a simple collector positioned above the head can collect solid particles suspended in the melted ice. The top thermal head exhibited a long lifetime and stable heating performance after being powered in water for 2 weeks. In addition, the ice temperature near the borehole was monitored to evaluate the range of heat disturbance caused by the thermal head.

Li, Y., Wang, Y., Wang, J., Pan, Z., 2020. Variation in permeability during CO - CH displacement in coal seams: 2 4 Part 1 - Experimental insights. Fuel 263, 116666.

http://www.sciencedirect.com/science/article/pii/S0016236119320204 The injection of CO into deep coal seams can improve the recovery of CH and contribute to the geological 2 4 sequestration of CO . To reveal the controlling factors associated with CO displacing CH , experiments were 2 2 4 conducted to simulate the process under different confining pressures (8, 12, 16, and 20 MPa) and CO injection 2 pressures (1 - 6 MPa). The results show that coal can adsorb more CO than CH . However, the permeability of 2 4 CH is greater than that of CO under inlet gas pressures of 1 - 5 MPa. For CH saturated coals, the CH 4 2 4 4 desorption volume is higher under CO displacing conditions compared to pure CH desorption processes under 2 4 the same pressures. The coal adsorbed CO decreases under high pore and confining pressures, indicating the 2 displacement results may be better in shallow buried coals. The axial, radial, and bulk strains of coal show steady, sharp, and then slow declining trends with decreasing pore pressures, and the inflection points generally occur at 5.25 and 3.25 MPa. Meanwhile, the strain in three directions decreases exponentially with the increase of effective stress, and the radial strain is higher than the axial strain under each confining pressure. With the combined influences of effective stress, matrix swelling/shrinkage, and gas slippage, the permeability decreases first and then increases with the decrease of pore pressure. With the decrease of pore pressure and the increase of confining pressure, the combined influence of the three factors on coal permeability gradually weakens. The results would be beneficial for controlling the injection process and permeability variation predicting during CO sequestration and the replacement of CH in coals at different burial depths. 2 4

Li, Z., Huang, H., Zhang, S., 2020. The effect of biodegradation on bound biomarkers released from intermediate- temperature gold-tube pyrolysis of severely biodegraded Athabasca bitumen. Fuel 263, 116669.

http://www.sciencedirect.com/science/article/pii/S001623611932023X Two severely biodegraded Athabasca oil sand bitumens from a single bitumen column have been pyrolyzed in gold tube at 2 °C/h to 300 - 525 °C with a step of 25 °C and their pyrolysates are geochemically characterized by gas chromatography-mass spectrometry. Sample A situated at the top of bitumen column is less biodegraded than sample B, which is located at the bottom. While newly released biomarkers mixed with preexisted bio- resistant species in pyrolysates makes reaction mechanism elucidation difficult, adsorbed and occluded biomarkers are likely released at intermediate-temperature pyrolysis (<425 °C) but covalently bonded biomarkers are mainly released at high- temperature (≥425 °C). Biodegradation influence on bound biomarkers has been demonstrated for the first time by the absences of regular steranes and diasteranes in both samples and C - C homohopanes in sample B of intermediate-temperature pyrolysates. Unusual variation of C 17α(H), 33 35 30 21β(H) hopane (C H) involved ratios in sample B also suggests that bound C H moiety has been partially 30 30 biodegraded. Caution should be taken when bound biomarkers are applied to reconstruct original source input