Adsorption and desorption characteristics of coal seam gas under infrared radiation

Infrared radiation technology can enhance rock permeability and promote methane desorption in coalbed methane thermal recovery. In this study, an experimental system with infrared radiation is developed to investigate the adsorption/desorption behavior of coal under different water contents. The results demonstrate that higher power levels of infrared radiation lead to decreased adsorption capacity and increased desorption capacity in coal. Specifically, employing 50 W infrared radiation results in a 30.9% increase in desorption capacity. Higher moisture content intensifies the desorption hysteresis effect, while this adverse impact can be mitigated by infrared radiation with greater power levels, exhibiting a stronger ability to reduce desorption-induced hysteresis. Additionally, a critical pressure for infrared radiation is established. Before and after this pressure, the influence of infrared radiation power on pressure sensitivity differs significantly. Finally, an improved Langmuir adsorption model considering infrared radiation power and moisture content is proposed and validated using experimental data. Our research expands the application of infrared radiation technology for enhanced coalbed methane recovery during actual mining operations.Document Type: Original articleCited as: Tu, Y., Zhang, Y., Dong, Y., Ma, Y. Adsorption and desorption characteristics of coal seam gas under infrared radiation. Capillarity, 2023, 8(3): 53-64. https://doi.org/10.46690/capi.2023.09.0

Depth and ages of calcareous nannofossil events from ODP Leg 184 sites, South China Sea

Sites 1146 and 1148 of Ocean Drilling Program Leg 184, in the South China Sea (SCS), comprise long sediment sections with a time span from the early Oligocene to the Pleistocene. Calcareous nannofossils from these two sites were biostratigraphically studied. We recognized 53 early Oligocene to Pleistocene events that are commonly found in open sea areas and can therefore be correlated within a large geographic range. This study also revealed that a few conventionally used nannofossil events are not suitable for the SCS, and further evaluation is needed. The lower Oligocene to Pleistocene sequences recovered at Sites 1146 and 1148 were subdivided into the 4 Paleogene zones and 21 Neogene to Quaternary zones of Martini, in correlation with the Paleogene to Quaternary zones of Okada and Bukry. This provided a lower Oligocene through Pleistocene nannofossil biostratigraphic framework. A significant unconformity was recognized in the Oligocene-Miocene transition, in which the upper part of Oligocene Zone NP25 and lower part of Miocene Zone NN1 were missing. The time span of the unconformity was estimated to be ~1 m.y. Very high sedimentation rates were seen in the Oligocene, relative low values were seen in the Miocene, and the highest values were seen in the Pleistocene, which was believed to be the result of tectonic and sedimentation history of the SCS

Study on the High-performance Composite Wall Panel Envelop of Building and its Relevant Joint Construction

Aiming at the general problems of envelop wall panel about the existing building, such as large surface density, low strength, poor service performance and high maintenance cost, a kind of high-performance composite wall panel is proposed in this paper. This wall panel takes high toughness cement-based composite material as shell and inorganic light thermal insulation material as core part. Its surface density equals to or is less than 70 kg/m2, heat transfer coefficient equals to or is less than 1 W/ (m2·K ), and the minimum bending failure load equals to or is more than 8 times of wall panel weight. Combined with the characteristics of high-performance composite wall panel, the “removable connection system” and “beveled tongue and groove type” joint structure are proposed to realize the construction of high-performance composite wall panel without moisture, nondestructive free disassembly and green recycling

Relationship chains of subhealth physical examination indicators: a cross-sectional study using the PLS-SEM approach

Abstract Subhealth is a transitional state between health and disease, and it can be detected through routine physical check-ups. However, the complexity and diversity of physical examination items and the difficulty of quantifying subhealth manifestations are the main problems that hinder its treatment. The aim of this study was to systematically investigate the physical examination performance of the subhealthy population and further explore the deeper relationships between indicators. Indicators were obtained for 878 subjects, including basic information, Western medicine indicators, inquiries of traditional Chinese medicine and sublingual vein (SV) characteristics. Statistical differences were analysed using R software. To explore the distribution of symptoms and symptom clusters in subhealth, partial least squares-structural equation modelling (PLS-SEM) was applied to the subhealth physical examination index, and a structural model was developed to verify whether the relationship chain between the latent variables was reasonable. Finally, the reliability and validity of the PLS-SE model were assessed. The most common subclinical clinical symptoms were limb soreness (37.6%), fatigue (31.6%), shoulder and neck pain (30.5%) and dry eyes (29.2%). The redness of the SV in the subhealthy group was paler than that in the healthy group (p < 0.001). This study validates the establishment of the directed acyclic relationship chain in the subhealthy group: the path from routine blood tests to lipid metabolism (t = 7.878, p < 0.001), the path from lipid metabolism to obesity (t = 8.410, p < 0.001), the path from obesity to SV characteristics (t = 2.237, p = 0.025), and the path from liver function to SV characteristics (t = 2.215, p = 0.027). The innovative application of PLS-SEM to the study of subhealth has revealed the existence of a chain of relationships between physical examination indicators, which will provide a basis for further exploration of subhealth mechanisms and causal inference. This study has identified the typical symptoms of subhealth, and their early management will help to advance the treatment of diseases