Mineral Molecules Research Articles

Modelling the temporal trajectories of human milk components.

This paper demonstrates how available data can be explored and utilized to conclude generic patterns in the temporal changes in Human Milk (HM) composition. The temporal trajectories of selected human milk components (HMC-s) were described, in the first four months postpartum, by a primary model consisting of two phases: a short linear phase in the colostrum, triggered by the parturition; and a longer second phase, where the concentration of the component converges to a steady state. The model was fitted to data available in a recently published database of temporal HMC trajectories both at the levels of individual molecules (such as specific fatty acid, oligosaccharide, and mineral molecules) and molecule-groups (such as total protein, total fat). The properties of the trajectories suggest that experimental designs should follow non-equidistant sampling times, with increasingly longer time intervals after the first week postpartum. A selected parameter, the final stationary level, of the primary model was then studied as a function of geographical location (secondary modelling). We found that the total variation of the concentration of specific HMC-s is dominantly due to the inherent biological differences between individual mothers and to less extent to the geographical location.

Molecular Simulation Study on the Effect of Co-Associated Minerals on Methane Adsorption and Mechanical Properties of Coal

When rockbursts and coal and gas outbursts simultaneously occur in a coal mine, changes in gas adsorption (concentration of ambient methane) and displacement of coal and rock must occur. The co-associated minerals in coal reservoirs can affect the mechanical properties and methane adsorption capacity, which are commonly disregarded. It is important to construct compound molecular structure models of coal and rock and conduct molecular dynamic simulations to gain a microscopic understanding of underground disasters. In this work, the molecular structure models of anthracite and coking coal–rock compound models containing different contents of calcite and kaolinite were constructed, and the methane adsorption amount and mechanical properties considering temperature, pressure, and mineral contents were simulated and analysed. The results showed that the methane adsorption amount of the compound models increased rapidly, then increased moderately, and stabilized eventually with increasing adsorption pressure, and the Langmuir fitting findings were good. The saturation adsorption amount of methane in the coal models linearly decreased with increasing temperature, while the methane adsorption heat increased. The presence of minerals adsorbed a certain amount of methane, and the methane adsorption amount increased with increasing mineral contents. The mechanical properties of coal molecules changed when mineral molecules such as calcite and kaolinite were present, which had opposite contribution effects. The addition of kaolinite minerals to the coal molecular model always increased the bulk modulus and shear modulus, while the addition of calcite decreased the bulk modulus of the anthracite, causing an increase in the brittleness of the models. The results of the study further explain the adsorption behaviour and mechanical properties of methane in coal and minerals.

Characterizing Fracture Characteristics of Heterogeneous Oil and Gas Reservoir by Using Microscopic Infrared Spectroscopy Technique ——Taking Carbonate Reservoir of the Wumishan Formation of Jixian System in Renqiu Burried Hill as an Example

Oil and gas reservoir fracture is not only the important reservoir space, but also the main passage of the oil and gas migration. Therefore, the characterization of fracture is of great importance. However, reservoir rocks have strong heterogeneity, how to characterize heterogeneous reservoir fracture accurately is an urgent problem to be solved. Microscopic infrared spectroscopy imaging technique can be used to analyze spectral curve of the mineral molecules, different peak characteristics were got, and rock medium composition, the size of the rock fracture, and fracture filler properties and other characteristics were obtained accurately. In this work, carbonate heterogeneous reservoir of Renqiu buried hill was taken as an example, based on the microscopic infrared spectroscopy imaging technique, by the analysis of core sample infrared imaging spectrogram and spectral curves of different characteristic regions, the physicochemical characteristics of the target sample and spatial distribution of the rock medium were obtained, the regions where rock fracture maybe occurred were predicted and the effectiveness of the fractures was analyzed. The results show that the main medium of rock sample is dolomite. The rock fractures contain hydrocarbon organic and salt-water inclusion, which mainly exist in dolomite medium. The proportion of salt-water inclusion is 51.7%, and that of alkane organic matter is 26.0% in the fracture filler. The fracutres extend from the upper left region of core sample to the lower right region, which shows that the extended region of the core sample may be the passage of fluid migration. The salt-water inclusions can impede the migration of oil and gas, resulting in the decrease of fractures permeability. The experimental results show that the width of fractures is 1～1.5 mm, which belongs to large fracture, oil and gas can pass the fractures smoothly, therefore, the effectiveness of the fracture is good. The results showed that it is feasible to characterize the fracture of heterogeneous reservoir by means of microscopic infrared spectroscopy imaging technique, and it provides a new method for the accurate characterization of the fracture of heterogeneous reservoir.