Rheological insights: A comparative analysis of viscosity determination techniques for liquid silicone rubber injection moulding simulation

Optimization of liquid droplet injection in steam turbine blades: Loss reduction, droplet size control, and performance enhancement

This study investigated wetting body migration and blind area distribution variations under different height differences (Δh) using indoor experiments and numerical simulations. Results show that the Δh of the injection hole shifts the wetting body intersection backward. Due to the increase in Δh, the vertical migration of the wetting peak at the No. 1 liquid injection hole accelerates, and the horizontal migration tends to be stable, which indicates that the Δh promotes the vertical seepage by changing the hydraulic gradient, which is beneficial to accelerate the leaching process. The migration of the wetting peak presents the characteristics of ‘fast first and then slow’, and it is easy to form a blind area in the later stage of leaching. When Δh is 0 and 3 cm, the blind area is concentrated between the two holes in the upper part of the ore heap. When Δh increases to 5 and 7 cm, the blind area expands to the top of the No. 1 hole. The simulation results show that although the increase in Δh can accelerate the recovery of water pressure in the near-end injection hole, it will increase the difference in leaching efficiency between ‘near-end’: when Δh is small, the wetting body diffuses symmetrically and the blind area is easy to eliminate; the increase in Δh leads to the asymmetric migration of the wetting body, and the remote area faces a significant risk of a blind area due to a low water pressure and low concentration.

Flow mixing and the oscillation of the stratified liquid layer forming below the free surface in the upper plenum of pool-type sodium fast reactors following a sudden decrease in reactor power or a scram could induce thermal stresses in the reactor core and support structure. Such an event has been investigated in the protected loss of power (PLOP) experiments performed at Purdue University using liquid gallium simulant. The present work performs computational fluid dynamics analyses to simulate liquid mixing and stratification in the upper plenum of the experiments for isothermal and colder liquid injection transients. In addition to investigating the formation of the liquid mixing eddies, the present analyses calculate the temperature and average velocity distributions in the plenum and compare the results for rigid and nonrigid liquid free surfaces. The performed analyses using the large eddy simulation turbulence model predict complex liquid mixing patterns that could not adequately be resolved using the unsteady Reynolds-averaged Navier-Stokes shear stress transport k-ω turbulence model. Results also show that the thickness of the hot liquid stratified layer near the free surface progressively decreases with increasing injection rate of the cooler liquid gallium into the plenum and the time of simulated transients. With a nonrigid gallium free surface, extensive formation of small turbulent mixing eddies occurs in the top plenum section and the thickness of the hot liquid stratified layer decreases faster with time than in the analysis with a rigid free surface. Simulation results of the axial distributions of the liquid temperature and the time-averaged flow velocity in the plenum are in good agreement with reported measurements in the Protected Loss of Power-40 (PLOP40) and Protected Loss of Power-60 (PLOP60) experiments with injection rates of cooler gallium into the upper plenum of 0.524 and 0.786 kg/s, respectively.

Well completion is a critical stage in the development of oil, gas, and gas-condensate wells, as it directly determines the efficiency of fluid flow from the reservoir into the wellbore. During drilling operations, the near-wellbore zone is often exposed to drilling and completion fluids, which can lead to formation damage, permeability reduction, and deterioration of reservoir properties. As a result, the primary objective of well completion is to remove drilling-induced damage, restore natural reservoir permeability, and create favorable conditions for sustainable production. This study examines the main methods used to initiate and enhance reservoir inflow during well completion operations. Common techniques include gradual replacement of high-density drilling fluids with lower-density fluids, lowering the fluid level in the wellbore, aeration methods involving simultaneous injection of gas and liquid, gas lift systems, and mechanical activation methods such as swabbing and piston operations. Particular attention is given to deep and high-pressure offshore gas and gas-condensate wells, where hydrostatic pressure reduction through controlled fluid displacement represents the most widely applied completion approach. The paper also analyzes the potential complications that may arise during completion and clean-up operations. These include formation damage due to fluid incompatibility, wellbore instability caused by rapid pressure drawdown, sand production in unconsolidated formations, incomplete displacement of drilling mud, loss of well control, equipment failure, hydrate formation, and corrosion issues. Such complications can significantly reduce well productivity, increase operational costs, and pose safety risks if not properly managed. To address these challenges, various mitigation strategies are discussed, emphasizing the importance of proper fluid design, gradual pressure management, real-time monitoring, and reservoir-specific completion planning. The application of compatible completion fluids, optimized drawdown rates, sand control techniques, and well-designed gas lift or aeration systems can effectively minimize operational risks and enhance well performance. The results highlight that a systematic and integrated approach to well completion, tailored to specific reservoir conditions, is essential for ensuring long-term well integrity, stable production, and operational safety. The findings of this study may be useful for petroleum engineers involved in the planning and execution of completion operations, particularly in complex offshore and high-pressure reservoir environments. Keywords: well completion, reservoir inflow, formation damage, hydrostatic pressure reduction, gas lift, wellbore stability, offshore gas wells.

Study of shock characteristics and losses in the transonic compressor with liquid injection

Gas–liquid swirl coaxial injectors are widely used in bipropellant liquid rocket engines due to their excellent atomization performance. However, under specific conditions, they may generate self-pulsation, which in turn can induce unstable combustion. Through cold-state atomization tests under continuous gas flow regulation, this study focuses on the initiation process of self-pulsation; systematically explores the evolution law of spray flow field characteristics with gas flow and reveals the initiation process and mechanism of self-pulsation. With the continuous increase in gas–liquid ratio, the spray of the non-recessed injector undergoes a continuous transition sequence of “steady state-transition state-self-pulsation.” However, for the injector with a large recess, an “intermittent” phenomenon occurs, characterized by a sequence of “self-pulsation-steady state-transition state-resumed self-pulsation.” The transition state mainly includes three stages: near-steady state, oscillation initiation, and oscillation intensification. In the transition stage, there exists low-intensity oscillation in the spray width, with alternating occurrences of steady spray and self-pulsation. Moreover, the conical liquid film inside the recess chamber squeezes the annular gas, leading to a reduction of the flow channel and an increase in the pressure outside the liquid film, which in turn pushes the liquid film toward the central axis. As the gas flow increases, the energy exchange between gas and liquid intensifies, eventually triggering self-pulsation. This study provides a theoretical reference for understanding the self-pulsation mechanism and optimizing the injectors of liquid rocket engines.

Development of an LC-ESI-MS/MS method for the determination of contaminants of emerging concern - towards extending quality surveillance of water resources.

This paper studies price and liquidity dynamics in the presence of costly short-selling when uninformed traders have limited willingness-to-pay to trade securities. In this setting, unraveling and Bayesian social learning interact to produce a novel mechanism, dynamic unraveling: Unraveling that generates signals that lead to future unraveling. Applying the theory, I show how dynamic unraveling explains low-volume crashes: falls in the prices of securities on low or declining trading volume. In this context, short-selling restrictions can make low-volume crashes more likely by intensifying dynamic unraveling, but liquidity injections have the opposite effect. This paper was accepted by Agostino Capponi, finance. Supplemental Material: The online appendix and data files are available at https://doi.org/10.1287/mnsc.2022.02412 .

ABSTRACT Traditional hydraulic fracturing technology suffers from low proppant efficiency and significant formation damage due to its reliance on high‐viscosity fluids. While phase‐change fracturing fluids overcome these issues by generating proppants in situ through liquid injection and formation‐triggered phase transformation, existing systems still face challenges such as inadequate proppant strength and poorly defined interfacial control mechanisms. This study aims to develop a novel phase‐change fracturing fluid system (MPCF) with enhanced strength, minimal reservoir damage, and high conductivity through molecular design and interfacial engineering. By introducing dicyclopentadiene (DCPD) into unsaturated polyester resin, a high‐strength functional monomer (PGC1) was synthesized, increasing its compressive strength from 42 to 95 MPa. The optimal MPCF formulation was established alongside an ideal interfacial tension range of 3.2–4.5 mN/m. Under these conditions, the resulting phase‐change proppant (MP) exhibits excellent comprehensive performance: sphericity of 0.9, breakage rate of only 1.5% at 60 MPa, and acid solubility as low as 0.18%. Flow capacity tests confirmed that MP outperforms conventional proppants across the 0–60 MPa closure pressure range. This work provides both a theoretical framework and a practical solution for improving proppant placement and fracture sustainability in unconventional reservoirs.

Controllable wetting of liquid on solid surface is meaningful for advanced science and engineering. Current researches about controllable liquid spreading are generally limited to unidirectional modes, while achieving multi-directional spreading on microstructured surfaces remains challenging. Herein, we propose a novel type of bulk-cusp microstructure, exhibiting 0 to 4-directional spreading of droplet without external energy input. This behavior occurs not only under single-drop deposition but also under continuous liquid injection. The bulk structure is assumed to have cross or square shape, implying relatively high and low coverage ratio of the precursor film, respectively. Owing to the drag effect of the precursor film, the cross-cusp microstructure facilitates controllable spreading of the main droplet, whereas the square-cusp microstructure just has guidance action on precursor film due to its low coverage ratio. Mechanism analysis reveals the capillary forces generated from the narrow gaps between adjacent cusps effectively separate the precursor film. The area coverage ratio of precursor film determined by the shape of the bulk influences the coupling or decoupling of the droplet body and precursor film. Such controllable multi-directional liquid spreading enables applications in lubrication enhancement and smart evaporation cooling.

Understanding the chemical processes that occur during the solvothermal synthesis of functional nanomaterials is essential for their rational design and optimization for specific applications. However, these processes remain poorly understood, primarily due to the limitations of conventional ex situ characterization techniques and the technical challenges associated with in situ studies, particularly the design and implementation of suitable reactors. Here, we present a versatile reactor suitable for in situ X-ray scattering, X-ray spectroscopy and infrared spectroscopy studies performed during solvothermal synthesis under autoclave-like, inert conditions. The reactor enables precise control of the temperature between -20°C and 200°C, pressure up to 8 bar, magnetic stirring, and injection of gas or liquids. The reactor's capabilities are demonstrated by comprehensively studying the solvothermal synthesis of magnetite nanoparticles from iron acetylacetonate in benzyl alcohol through in situ X-ray scattering and spectroscopy, and attenuated total reflection infrared (ATR-IR) spectroscopy.

Innovative Non-Inverted ILM Free Flap Covering Technique for Unclosed Macular Hole Repair.

Ammonia, a carbon-free compound, holds significant potential as a fuel in internal combustion engines. Recent research has revealed the limitations of gaseous ammonia use and highlighted the need to inject it in the liquid phase at higher pressures into the combustion environment to mitigate these shortcomings. This study focuses on investigating the flash-boiling effects of high-pressure liquid ammonia spray in a constant volume combustion chamber (CVCC) using a hollow-cone gasoline direct injection injector. Based on high-speed Schlieren and shadowgraph imaging data, the spray characteristics under varying ambient conditions are characterized. In particular, parameters such as the spray cone angle, penetration length, and plume ratios are studied to characterize the transformation of liquid ammonia spray into different spray regimes, characterized by flash-boiling phenomena. Furthermore, this work establishes a correlation between an increase in the ambient temperature of the CVCC and the transition into different regimes, as evidenced by the characteristics of the spray plume. Furthermore, the cooling effects of high fuel injection pressures at elevated CVCC ambient pressures are investigated to study the impact of pressure differentials on the drop in temperature caused by the injection of liquid ammonia. The findings of this study can serve as a foundation for the development of high-pressure liquid ammonia direct injection techniques, leveraging the rapid flash-boiling behavior of liquid ammonia.

This study analyzes the economic phenomenon known as the "Purbaya Effect" in the Indonesian capital market during the second half of 2025. This phenomenon is characterized by a significant surge in the Jakarta Composite Index (IHSG), which broke the All-Time High (ATH) record 21 times within four months following the appointment of Purbaya Yudhi Sadewa as Minister of Finance. Using a mixed-methods approach combining quantitative market data analysis and qualitative policy review, this research finds that the "Purbaya Effect" is driven by aggressive liquidity injection policies (Rp 200 trillion), institutional trust built during his tenure at LPS, and strong narrative economics. However, this study also identifies significant risks related to exchange rate volatility and potential economic overheating. The findings suggest that while the "Purbaya Effect" successfully restored short-term investor confidence, long-term sustainability depends on the balance between growth acceleration and macroeconomic stability.

Solid rocket motors (SRMs) play a pivotal role in space exploration owing to their reliability and high thrust-to-weight ratios. SRM propellant health monitoring is in critical demand owing to the complex operational scenarios throughout the entire life cycle of SRMs. To achieve in situ detection of three-dimensional stress, this study introduces a novel flexible three-dimensional stress sensor (FSS). First, a liquid metal pressure-sensing element with a variable cross-section was designed and numerically modeled. The performance of the FSS under different loading conditions was analyzed using finite element modeling. The sensing element prototype was fabricated using mold casting and liquid metal injection methods. The fabricated sensing-element prototype with an area ratio of 1:5 exhibited a sensitivity coefficient of 1.5%/kPa at a pressure of 300 kPa, a maximum hysteresis error of 3.98%, and a stability error of 0.17%. Finally, the FSS was developed by integrating multiple pressure-sensing elements and encapsulating the force-concentrating layers. The fabricated FSS prototype was characterized using simulated propellant experiments. Via comparison with the simulation results, the FSS was found to detect multiaxial stress differences when embedded within a propellant.

The presence of H<sub>2</sub>S in petroleum compromises the integrity of industrial equipment, affects the quality of by-products, and poses environmental and occupational challenges that increase costs and operational risks. A common solution to mitigate this contaminant is the continuous injection of liquid H<sub>2</sub>S scavengers into the production stream. Most technical publications focus on H<sub>2</sub>S scavengers for gaseous hydrocarbons and aqueous fluids at temperatures below 70°C, but there are few references regarding scavenger performance in liquid organic media at temperatures above 70°C. This article presents the results of a comparative study on the H<sub>2</sub>S scavenging capacity of various concentrated active compounds and commercial products used in the petroleum industry. The methodology involves subjecting oils with different densities to a constant flow of gas with a known H<sub>2</sub>S concentration at 33.1 kPa and 130°C. The H<sub>2</sub>S concentration is measured in the gas phase using gas chromatography and in the liquid phase by potentiometric titration throughout the test period, after passing through the reaction system and before and after the introduction of a known aliquot of the H<sub>2</sub>S scavenger. The methodologies employed allow for the evaluation and comparison of the H<sub>2</sub>S scavenging capacity of the products analyzed. This enables classification according to efficiency, using tests that simulate conditions closer to field applications, with a predominantly organic environment, similar to new oil wells where the water content is less than 1 %(v/v). Among the commercial H<sub>2</sub>S scavengers evaluated, the product based on ethoxylated compounds showed the best performance, while MEA-triazine and glyoxal-based scavengers exhibited lower performance, with glyoxal being slightly more effective than MEA-triazine. The zinc carboxylate-based scavenger demonstrated the lowest performance among the products tested. The study also showed that the mass of H<sub>2</sub>S reacted is proportional to the product dosage, within the tested range of 500 mL/L to 1000 mL/L for all products. The information generated enables informed decisions regarding the best product for oil production, aiming for greater efficiency and a lower volume of injected scavenger. This approach supports operational safety, regulatory compliance, and minimal impact on oil refining stages due to residual scavengers and reaction products present in the produced oil.

The exploration and production of oil in Brazil are increasingly focused on deeper reservoirs and water columns, significant technological challenges related to material selection and corrosion control. The presence of H<sub>2</sub>S in crude oil undermines the integrity of industrial equipment and the quality of derived products, contributing to environmental and occupational issues that lead to heightened costs and risks associated with the operation of these industrial units. One of the solutions is the continuous injection of liquid H<sub>2</sub>S scavengers to mitigate this contaminant in industrial fluids. Testing yields important information regarding the performance of these products; however, the multitude of variables present in these tests complicates the ability to draw conclusive and reproducible observations. Furthermore, the impact of new products on subsequent processes following the injection point complicates the execution of field tests, and the careful implementation of these tests directly disrupts the normal operational and production routine. This article aims to present a detailed methodology for comparing the performance of H<sub>2</sub>S scavengers composed of different active materials in a predominantly organic medium at temperatures reaching up to 130°C, conditions resembling those encountered at the onset of production from new oil-producing wells with water content of less than 1 %(v/v). Consequently, the methodologies described allow for the assessment, comparison, and differentiation of the H2S scavenging capacity of various commercial H<sub>2</sub>S scavengers used in the oil industry, enabling their classification according to efficiency. Additionally, it consolidates in single test conditions that are closer to field application and capable of evaluating mixtures of water and oil in proportions ranging from 0 to 100 %(v/v), aqueous solutions with salinity up to 200 g/L in NaCl, temperatures between 30°C and 250°C, and pressures from atmospheric pressure up to 1034 kPa. The methodology allowed for obtaining, in addition to information on H<sub>2</sub>S scavenging capacity, an indication of the reaction time and rate required to achieve the minimum H<sub>2</sub>S content in both gas and liquid phases, facilitating the optimization of treatment protocols in oil platforms, onshore and offshore, subsea and topside, terminals, tanks, and pipelines. Among the commercial H<sub>2</sub>S scavengers evaluated in this study, the one based on ethoxylated compounds (ETO-C) demonstrated superior performance compared to the MEA-triazine-based product (TRI-C) under the same experimental conditions.

High-intensity liquid injection is a key factor influencing the deformation and instability of slopes in ion-adsorbed rare earth ores. Current research on water migration in slopes primarily relies on point-to-point monitoring using sensors, which limits the ability to comprehensively monitor the ore body. To address this limitation, a test block from an ion-adsorbed rare earth ore was selected for the study. High-density resistivity methods, along with sensor monitoring technology, were employed to monitor the water content and apparent resistivity of the ore body. A correlation model was established between these two parameters. Based on this model, the distribution and migration patterns of water within the ore body were analyzed, demonstrating the effectiveness of high-density resistivity method in investigating water migration in ion-adsorbed rare earth ores. The field test results revealed a significant power function relationship between the water content and apparent resistivity of the ore body. During the solution injection process, the infiltration area evolved from a droplet shape to a peach shape and ultimately to a hat-shaped pattern. In the non-injection areas, the water content in the lower part of the ore body tended toward saturation, while the topsoil layer remained unaffected by the leaching agent. This created a potential slip zone in the lower part of the topsoil, posing a landslide risk. Additionally, the cohesion and internal friction angles reached their lowest values once the ore body was fully saturated. These findings highlight the importance of enhanced safety inspections during the middle and later stages of solution injection.

A custom scanning electrochemical cell microscopy (SECCM) platform is built to rapidly search for electrochemical reduction conditions of a hematite thin film, which is prepared by direct liquid injection chemical vapor deposition (DLI-CVD), for enhanced photoelectrochemical (PEC) water splitting. An array of hematite spots is created under various SECCM reduction potentials and time lengths, followed by subsequent screening with the same SECCM probe under PEC conditions to identify the optimum reduction conditions. For example, the SECCM study shows that 6.5% reduction of a 128 nm hematite film shows the optimal PEC performance. This reduction condition obtained with SECCM can be extended to a bulk film to resemble the enhanced PEC activities. A Machine Learning model is built based on the quality data obtained with SECCM to guide the experimental efforts of searching for an efficient photoelectrode for PEC water splitting.