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In the field of cement, if the formation cannot be given sufficient pressure to maintain stability during construction, pressure control failure may occur, leading to the leakage of liquids and gasses from the formation to the wellbore. In addition, irregular wellbore diameter and casing eccentricity are important factors that are easily overlooked and affect the prediction of ECD (Equivalent Circulation Density) calculation. This results in major accidents and ecological disasters, further impacting the global environment. This study focuses on a well in the eastern oilfields of China, and based on a rheological experiment of high temperature and high pressure, an irregular eccentric wellbore model is established according to the measured wellbore diameter and eccentricity data to calculate the ECD of the whole cementing process. Then, a data set is constructed and analyzed using the random forest method to quantitatively evaluate influencing factors such as displacement, rheology, density, and eccentricity on the bottomhole and wellbore ECD. Results find that the density of cement slurry and drilling fluid has the most significant impact on the maximum ECD, with the impact reaching 0.3142 and 0.2902, respectively, and the main factors that affect the minimum ECD are the density and rheological changes in the drilling fluid, reaching 0.7014 and 0.2846. These research findings will contribute to the precise control of wellbore pressure during cementing operations, further ensuring the safety of cementing operations, and laying a technical foundation for the automation and intelligentization of subsequent cementing operations. [ABSTRACT FROM AUTHOR]

The key step in preparing mesoporous silica is to remove the organic template agent, and the most common method used to achieve this goal is high-temperature calcination. However, this method has many disadvantages, one of which is that it reduces the silanol density on the surface of mesoporous silica, which affects its subsequent modification. Ionic liquids (ILs) are often used as extractants. In this work, the 1-butyl-3-methylimidazolium chloride ([C4mim]Cl) IL is considered, and the effects of its concentration, reaction temperature, and reaction time as well as HCl concentration on the extraction rate and silanol density were investigated using an IL extraction template agent (cetyl trimethyl ammonium bromide (CTAB)). The results show that an IL concentration of 10%, a reaction temperature of 120 °C, a reaction time of 12 h, and an HCl concentration of 1% are the best reaction parameters; with these parameters, the extraction rate and the silanol density were found to be 93.19% and 2.23%, respectively. The silanol density of mesoporous silica treated by calcination is only 0.81%. A higher silanol density provides more reaction sites, so that the modified mesoporous silica treated with the IL can be loaded with more Zn ions. [ABSTRACT FROM AUTHOR]

In order to study the chip shapes and the influence law of drilling parameters and vibration parameters on drilling forces (thrust force and torque) during low frequency vibration drilling of TC4 titanium alloy. Based on a self-developed low-frequency vibrating tool holder, low-frequency vibration drilling tests of titanium alloy were carried out by single factor method and orthogonal test method respectively. Chip shapes and drilling forces under different drilling conditions were analyzed. Empirical formulas of thrust force and torque were established. The influence factors of drilling forces were analyzed by visual analyses and variance analyses. Results show that when TC4 titanium alloy is drilled in low frequency vibration, the ratio of amplitude and feed is close to the critical chip breaking value of 0.81, the chip breaking is reliable, and the chip discharging is smooth. The instantaneous drilling force of low frequency vibration presents regular sine wave, and the dynamic component of drilling force is much larger than the ordinary drilling. The thrust force and torque mean may be reduced by 10%~15% and 15%~20% respectively than that of the ordinary drilling. The feed rate has the most significant influences on the drilling forces, the amplitude takes second place, the drilling speed has the least influence. The established vibration drilling experience model error is kept within 10%, which may accurately predict the drilling forces within the selected parameters of the test systems. [ABSTRACT FROM AUTHOR]

Background: An imbalance in energy metabolism serves as a causal factor for type 2 diabetes (T2D). Although metformin has been known to ameliorate the overall energy metabolism imbalance, but the direct correlation between metformin and central carbon metabolism (CCM) has not been thoroughly investigated. In this study, we employed a high-performance ion chromatography-tandem mass spectrometry (HPIC-MS/MS) technique to examine the alterations and significance of CCM both before and after metformin treatment for T2D., Methods: We recruited 29 participants, comprising 10 individuals recently diagnosed with T2D (T2D group). Among these, 10 patients underwent a 4-6-week treatment with metformin (MET group). Additionally, we included 9 healthy subjects (CON group). Employing HPIC-MS/MS, we quantitatively analyzed 56 metabolites across 18 biologically relevant metabolic pathways associated with CCM. Univariate and multivariate statistical analyses were utilized to identify differential metabolites. Subsequently, correlation analyses and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted on the identified differential metabolites., Results: We identified seven distinct metabolites in individuals with T2D ( p < 0.05). Notably, cyclic 3',5'-Adenosine MonoPhosphate (AMP), Glucose 6-phosphate, L-lactic acid, Maleic acid, and Malic acid exhibited a reversal to normal levels following metformin treatment. Furthermore, Malic acid demonstrated a positive correlation with L-lactic acid (r = 0.94, p < 0.05), as did succinic acid with malic acid (r = 0.81, p < 0.05), L-lactic acid with succinic acid (r = 0.78, p < 0.05), and L-lactic acid with glucose-6-phosphate (r = 0.72, p < 0.05). These metabolites were notably enriched in pyruvate metabolism ( p = 0.005), tricarboxylic acid cycle (TCA) ( p = 0.007), propanoate metabolism ( p = 0.007), and glycolysis or gluconeogenesis ( p = 0.009), respectively., Conclusions: We employed HPIC-MS/MS to uncover alterations in CCM among individuals recently diagnosed with T2D before and after metformin treatment. The findings suggest that metformin may ameliorate the energy metabolism imbalance in T2D by reducing intermediates within the CCM pathway.

In this work, a novel sustained released system (VCSB-Zn(II)) for zinc supplements was built by vanillin-chitosan Schiff base (VCSB) chelated with Zn 2+ to improve the zinc trace element utilization ratio. Samples were characterized by FT-IR, 1 H NMR, XRD, SEM, and TGA. The results showed that VCSB exhibited a more excellent chelation capacity of Zn 2+ than chitosan. The chelation capacity of VCSB was about 1.7 times more than that of chitosan, corresponding to 50.96 mg/g and 29.91 mg/g, respectively. Furthermore, VCSB-Zn(II) showed excellent sustained released performance at simulated gastric fluid because of the acid slow-dissolving ability. And the higher the CN content of VCSB, the higher the cumulative release rate (R i ) of Zn 2+ , the highest R i reached 77.81%. The sustained released curves were described by the first-order and Korsmeyer-Peppas equation, which described the Zn 2+ sustained released performance caused by the dissolution of VCSB-Zn(II) and Fick diffusion. This Zn 2+ sustained released system shows great potential in the application in the field of trace elements supplements for animals., (Copyright © 2021 Elsevier B.V. All rights reserved.)