ACS Omega最新文献

High-quality LiTbF₄ crystals were successfully grown for the first time using the Bridgman method with a platinum (Pt) crucible vacuum-sealed technique. Using the laser sealing technique, the raw materials were sealed directly in a Pt crucible under high-vacuum conditions to control the composition and purity of the melt. A single-crystal rod with dimensions of Φ12 mm × 80 mm was grown using this method, and several samples were prepared to characterize the optical properties. The as-grown crystal exhibited a narrow full width at half-maximum (fwhm) of 0.038° on the (112) plane, low absorption coefficients (<0.005 cm^–1 at 1064 nm), and high transmittance in the 400–1500 nm wavelength range. The results indicated that the Bridgman method with the Pt crucible laser-sealed technique is an effective way for growing high-quality LiTbF₄ crystals, and is expected to be applied for growing other fluoride crystals.

In response to the issues of abnormal bed temperature fluctuations and inefficient combustion that occur during the flexible operation of the circulating fluidized bed (CFB) boiler combustion system, which is characterized by strong coupling, nonlinearity, and large inertia, this paper presents a novel monitoring and optimization approach that integrates a deep learning model with a mechanism model. Specifically, the Informer algorithm is utilized to construct a bed temperature range prediction model, thus enabling the real-time monitoring of the intricate change trends of the in-furnace bed temperature. Considering the poor reliability of combustion optimization target values derived from data model predictions and the constraints on the optimization upper limit, this article further combines the mechanism model to comprehensively determine the combustion optimization target values from the design perspective. The results indicated that the Informer prediction model exhibited a root-mean-square error (RMSE) of 3.385 °C, a mean absolute error (MAE) of 2.45 °C, and a mean absolute percentage error (MAPE) of 0.268% on the rolling test data set, demonstrating high overall prediction accuracy. The steady-state operational data of the generating unit at 300 and 200 MW were selected to validate the mechanism model, with particular emphasis on comparing the distribution trends of pressure and temperature along the height of the furnace. The outcomes revealed good consistency, indicating the model’s high accuracy in performance simulation. By integrating the data model with the mechanism model, the target values for optimizing bed temperature performance under steady-state conditions were determined. In comparison to using the data model alone, during the 240 and 280 MW operating conditions, the average thermal efficiency of the boiler increased by 0.19 and 0.13%, respectively. Concurrently, the coal consumption rate for power generation decreased by 0.6707 and 0.4453 g/(kW·h), respectively, and the carbon emissions reduced per kilowatt-hour of electricity generated were 1.6738 and 1.1113 g, respectively.

This study focused on the design, synthesis, chemical characterization, and potential inhibitory study of thiazole-methylsulfonyl derivatives against carbonic anhydrase enzymes. The synthesized compounds, with the characteristics of both the thiazole ring and methyl sulfonyl group, were synthesized through a two-step scheme, and their structures were confirmed through NMR spectroscopy and HRMS. Additionally, the structure of compound 2b was elucidated by an X-ray study. An enzyme inhibition assay was performed to assess their biological activity against carbonic anhydrases, and the compounds showed promising results against carbonic anhydrases I and II, highlighting their potential for specificity and targeted therapy. The effects of these molecules on in vitro enzyme activities were investigated by spectrophotometric methods. For this purpose, the concentrations (IC₅₀ values) of compounds that inhibited the biological activities of carbonic anhydrase isoenzymes (hCA I and hCA II) by 50% were calculated. The IC₅₀ values were found between 39.38–198.04 μM (AAZ IC₅₀ = 18.11 μM) for hCA I and 39.16–86.64 μM (AAZ IC₅₀ = 20.65 μM). Molecular docking studies have shown that compounds 2a and 2h exhibit stable interaction networks with targeted enzymes. The combinations of both studies, enzyme inhibition assay and molecular docking studies, thus enlighten the significance of these compounds for further optimization for pharmacological profiling and for developing therapeutic agents against carbonic anhydrase. Moreover, the study provides insight for future research on the synthesis of heterocyclic compounds against carbonic anhydrase for therapeutic applications.

The injection of flue gas originating from coal-fired power plants into underground strata, wherein carbon dioxide (CO₂) is adsorbed by coal, achieves multiple effects: inhibiting coal spontaneous combustion, displacing gas, and sequestering CO₂. To study the chemisorption characteristics of CO₂ on coal surfaces at a microscopic level, models such as the Tashan lignite three-dimensional model and graphene-doped functional group coal model were constructed. The adsorption behavior of coal and CO₂ was simulated using methods such as Monte Carlo, molecular dynamics, and density functional theory. Results reveal that the average isosteric heat of adsorption is close to the critical threshold, with a maximum exceeding 13 kcal/mol, confirming chemical adsorption. Radial distribution functions indicate that CO₂ is most likely to undergo chemisorption near carboxyl groups. The density of states of the four oxygen-containing functional group-graphene coal models increased around −7 and −4 eV before and after CO₂ adsorption. Analysis of the partial density of states reveals resonance peaks in the P orbital between CO₂ and carboxyl groups, indicative of electron accumulation and bond formation. These findings provide theoretical support for flue gas injection into coal seams to achieve carbon-stable sequestration.

Delving into the intricate role of phytonutrients is paramount to effectively preventing and treating chronic diseases. Phytonutrients are “plant-based nutrients” that positively affect human health. Phytonutrients perform primary therapeutic functions in the management and treatment of various diseases. It is reported that different types of pathogenesis occur due to the excessive production of oxidants (reactive nitrogen species and reactive oxygen species). The literature shows that a higher intake of fruits, vegetables, and other plant-based food is inversely related to treating different chronic diseases. Due to many phytonutrients (antioxidants) in fruits, vegetables, and other medicinal plants, they are considered major therapeutic agents for various diseases. The main purpose of this review is to summarize the major phytonutrients involved in preventing and treating diseases. Fourteen major phytonutrients are discussed in this review, such as polyphenols, anthocyanin, resveratrol, phytosterol (stigmasterol), flavonoids, isoflavonoids, limonoids, terpenoids, carotenoids, lycopene, quercetin, phytoestrogens, glucosinolates, and probiotics, which are well-known for their beneficial effects on the human body and treatment of different pathological conditions. It is concluded that phytonutrients play a major role in the prevention and treatment of diabetes mellitus, obesity, hypertension, cardiovascular disorders, other types of cancers, neurological disorders, age-related diseases, and inflammatory disorders and are also involved in various biological activities.

In order to study the diffusion distribution laws of harmful gases in municipal heating underground pipe trenches under various influencing factors, a 1:1 scale model of the municipal heating underground pipe trench was established by using CFD simulation software. This study examined the impact of closed pipe trench conditions, natural ventilation, mechanical ventilation, and gas dispersing rates on the distribution of methane diffusion in the heating underground pipe trench and was verified through on-site experiments. The findings are as follows: (1) the gas in the heating pipe trench flows violently at the bottom of the pipe trench and the examination room and the top air flow rate is small, resulting in higher top temperature and lower bottom temperature; (2) under closed trench conditions, methane gas exhibits a vertical layered distribution near the release source, with higher concentrations in the upper part compared to the lower part. This layered effect diminishes with increasing distance; (3) natural ventilation effectively reduces methane gas content in the pipe trench. Ventilation in the same direction as methane release is not conducive to gas dispersion; (4) in the closed state and natural ventilation state, with the increase of escape source rate, the growth law of methane is linear and exponential distribution, respectively; and (5) mechanical ventilation rapidly and effectively reduces methane gas content. The research results contribute theoretical insights into confined space ventilation, alarm system installations, and personnel operation, ensuring staff safety in these environments.

During shallow hydrate reservoir drilling in deepwater, hydrates in the reservoir and drilling cuttings decompose under specific temperatures and pressures. This process impacts the temperature of the reservoir and wellbore as well as the concentration of cuttings, leading to intricate gas–liquid–solid multiphase dynamics in the wellbore. These dynamics can cause significant errors in the predicted wellbore pressure, which may lead to blowout accidents. This paper examines the effects of hydrate decomposition on the reservoir temperature field, considering the migration of cuttings and the decomposition of hydrate in both the cuttings and the reservoir. A multiphase flow model was developed for drilling in deepwater shallow hydrate formations, and its accuracy was validated using experimental data. The study also demonstrates the influence of the wellhead backpressure, drilling fluid density, drilling fluid inlet temperature, and rate of penetration (ROP) on the hydrate decomposition rate, void fraction, mud pit gain, and bottom-hole pressure. The simulation results indicate that applying wellhead pressure, increasing drilling fluid density, reducing the inlet temperature of drilling fluids, and lowering ROP can effectively inhibit hydrate decomposition, reduce void fraction, and help maintain bottom-hole pressure.

Lake Kivu, located on the border between the Democratic Republic of Congo (DRC) and Rwanda, contains vast amounts of dissolved methane and carbon dioxide, presenting a unique opportunity for power generation. The primary challenges are maintaining the lake’s stability, minimizing environmental impacts, and optimizing methane recovery to ensure economic viability. Environmental concerns associated with the current production system include the release of large amounts of CO₂ and the impact of H₂S on oxygen depletion, prompting the search for alternative methods. This study investigates the energy efficiency of a new proposed method of gas extraction from Lake Kivu using a process simulation. We conducted a comparative analysis of two biogas upgrading techniques, water and amine scrubbing, under various scenarios. While water scrubbing achieves an optimal energy efficiency of ∼1.2 kWhe/m³ of extracted water, amine scrubbing, when integrated with cogeneration, offers similar energy efficiency with the added benefit of reducing impacts on the lake’s biozone. However, amine scrubbing involves higher capital costs and higher on-shore facility requirements. Overall, the net energy efficiency of extraction ranges between 0.8 and 1 kWhe/m³ of extracted water. This study emphasizes that optimizing degassing pressure must account for lake stability and environmental considerations alongside energy efficiency. The proposed integrated workflow offers a balanced approach to sustainably harnessing Lake Kivu’s gas resources.

Two methanol production process options based on gas-to-methanol (GTM) technology according to the CO₂ feed location (option 1: CO₂ is fed to the methanol synthesis unit via a reformer; option 2: CO₂ is directly fed to the methanol synthesis unit) are proposed. In this study, we simulated these two methanol synthesis process options at a steam/natural gas (S/NG) ratio of 1.5 and evaluated the environmental impact of the two options by comparing the potential environment impact (PEI) according to the recycle ratio of unreacted syngas. We simulated the process using Aspen Plus and quantitated the PEI rates using the Waste Reduction (WAR) algorithm (version 1.0). The results show that in both cases PEI rates decrease with increasing recycle ratio of the unreacted syngas and thus become environmentally friendly. Also, it was demonstrated that option 1 is more environmentally friendly than option 2, and when the recycle ratio increases from 0 to 0.9, the total rate of PEI output decreases from 176.3 to 93.4 PEI/h by 53.0% and the PEI generation rate decreases from 149.9 to 67.0 PEI/h by 44.7%.