Search Results (1,052)

Wax deposition occurs to varying degrees in most oil and gas wells. The basic data of existing wax precipitation prediction models are mainly single-component wax experimental data based on the melting process of wax crystals during heating, which is quite different from the cooling crystallization process of wax in oil and gas production. Moreover, the published solubility test data of binary n-alkanes are mainly concentrated in the range of nC10–nC36, leaving existing thermodynamic models without available data for predicting the behavior of high-carbon alkanes. Based on the idea of wax crystallization and precipitation during cooling, this study experimentally determined the solid–liquid equilibrium solubilities of high-carbon n-alkanes (nC38, nC40, nC44, nC48 and nC50) with different concentrations in n-heptane, n-nonane and n-dodecane, as well as the crystallization parameters of pure substances, by using a DSC instrument. This effectively fills the gap in the basic physical property data of long-chain alkanes (more than nC36) and the cooling process in existing studies. In addition, we measured the crystallization parameters of pure high-carbon n-alkanes (nC38, nC40, nC44, nC48 and nC50) during cooling, including crystallization temperature, transition temperature, crystallization enthalpy and transition enthalpy under cooling conditions. The experimental data are in good agreement with the solubility predicted by the ideal solution model for the cooling process, with an average absolute percentage error of less than 10% and average solubility deviation generally within 0.078 mol%. This indicates that the ideal solution model has good accuracy for predicting the precipitation of n-alkane wax and n-alkane solvents. This study provides basic data for the prediction theory of paraffin precipitation. Full article

The chemical agent injection modes and displacement characteristics of chemical compound flooding, consisting of a plugging agent, an oil displacement agent, and a viscosity reducer, were investigated by laboratory experiments for target heavy oil reservoirs after multiple cycles of huff-and-puff. The performances of the oil displacement agent, viscosity reducer and plugging agent were evaluated, and the formulation and concentration were optimized. The oil displacement effects and displacement characteristics of different injection modes were studied by sand-filled two-pipe models. The experiment results showed that alternating injections of the oil displacement agent and viscosity reducer yielded better results than their mixed injection, and small segments alternating injections achieved the highest recovery. The larger the dosage of the oil displacement agent, the larger the maximum liquid production ratio between the high- and low-permeability layers, but with the smaller the liquid production reverse duration. The larger the dosage of the viscosity reducer, the greater the water cut decrease but the smaller the maximum liquid production ratio. For chemical compound flooding in the Zhong’er block in the Gudao oilfield, the recommended injection mode was 0.1 PV plugging agent + 2000 mg/L of oil displacement agent + 0.5% viscosity reducer, with small segments of the oil displacement agent being followed by a viscosity reducer at an injection slug ratio of 6:4. However, the injection mode depends on the prices of oil and the chemical agent. When prices fluctuate, the chemical agent concentration should be adjusted accordingly. Full article

About 10% of plastic products are recycled worldwide, highlighting the need for technology improvements based on deeper material understanding. In packaging, which holds the highest market share in plastics demand, odor and potential hazards remain critical barriers to high-quality recycling. Conventional characterization relies on chromatography with extensive sample preparation. A gas chromatography system equipped with thermal desorption and dual flame ionization and mass spectrometric detection (ATD-GC/FID-MS) was established to analyze recyclates directly, thereby accelerating technology adaptation and guiding follow-up analyses. For calibration and validation, liquid standards were introduced into TenaxTA-filled tubes via a packed column injector and compared to a loading rig. The injector exhibited losses for higher-molar-mass compounds and solvent-dependent signal shifts. A storage study on compounded recycled polypropylene stored under various conditions showed that samples not frozen in sealed containers should be analyzed within 30 days. Experiments with varying sample geometries demonstrated that higher surface-to-volume ratios increase volatile release and variability in results, highlighting the need for uniform shapes. Applying the method to recycled yogurt cups enables the identification and quantification of contaminants, facilitating optimization of the washing process. Overall, ATD-GC/FID-MS provides a rapid screening tool for recyclate quality control and supports the improvement of recycling technologies. Full article

Hydroxyapatite (HAp) is a key bioceramic for biomedical applications, but conventional pressureless sintering (PS) requires high temperatures that can promote phase degradation. Here, we compare PS (1100 °C/180 min) and cold sintering process (CSP) (150 °C/450 MPa/30 min) for pure HAp and an HAp composite containing 4 wt.% niobium–phosphate bioglass (BG), using a 2 M H₃PO₄ transient liquid (10 wt.%). CSP increased relative density from 73.10% to 79.92% for HAp and from 68.43% to 83.54% for HAp/BG, representing up to a 22.1% gain compared with PS. One-way ANOVA confirmed a significant effect of processing route/composition on relative density (F(3,24) = 919.69, p < 0.05), and Tukey HSD indicated that all groups differed statistically. SEM revealed a markedly more consolidated and homogeneous microstructure for CSP, particularly for HAp/BG, consistent with enhanced dissolution–reprecipitation and pore filling. XRD showed that PS at 1100 °C led to partial HAp degradation with β-TCP formation, whereas CSP preserved the HAp phase with broader peaks, smaller crystallite size, and higher specific surface area. These results demonstrate CSP as an efficient low-temperature alternative for densifying HAp-based bioceramics, with BG addition further improving consolidation. Full article

To address the challenges of excessive local thinning, poor surface quality, and low production efficiency in traditional multi-pass deep-drawn aluminum alloy fairings, this study investigates the effects of process parameters—including liquid chamber pressure, holding force, and differentiated lubrication schemes—on the liquid-filled forming performance and wall thickness distribution of a 460 × 280 × 1.5 mm thin-walled 2A12 aluminum alloy fairing. Employing an integrated liquid-filled forming technique combining a flexible punch with a rigid die, the research combines numerical simulation with experimental validation. The study demonstrates good consistency between experimental results and numerical simulations. The optimal forming process parameters are liquid chamber pressure of 10 MPa, holding force of 1100 kN, and a lubrication scheme (friction coefficients of 0.01 for the flange and forming zones and 0.06 for the transition radius zone). Under these parameters, part wrinkling and cracking are effectively suppressed, achieving optimal wall thickness uniformity in the formed parts, with a maximum thinning rate of only 6.6%. The proposed liquid-assisted forming process and differentiated lubrication scheme provide a new technical pathway for high-precision manufacturing of thin-walled complex curved components made of 2A12 aluminum alloy. Compared to traditional multi-stage drawing processes, both forming efficiency and quality are significantly improved. Full article

This study investigates the acoustic pressure field in a 20 kHz sonoreactor filled with water. A modular sonoreactor and ultrasonic stack were developed at the Łukasiewicz-ITR laboratory. Modal, harmonic response, and harmonic acoustic analyses were performed using the ANSYS Workbench, considering two reactor heights (800 mm and 550 mm). Experimental tests using aluminium foils were conducted, and the results were compared with FEM simulations. The bulk viscosity of the liquid was found to have a significant impact on the numerical results. The novelty of this work lies in estimating an effective bulk viscosity that enables accurate representation of the pressure field distribution within the tank. This parameter is theoretical and, as defined in this study, accounts for the overall energy losses associated with cavitation rather than representing an intrinsic material property. The proposed simulation approach reduces computational time and cost while maintaining agreement between predicted and experimental pressure fields. Good consistency was achieved when the effective bulk viscosity was set to 1300 Pa·s. The presented methodology may support further development and optimization of sonoreactors. It enables rapid evaluation of various geometries, providing a foundation for prototype development or subsequent detailed analyses. Full article

Efficient ortho–para hydrogen conversion is essential to suppress spontaneous heat release and boil-off losses during cryogenic liquid hydrogen storage and pre-liquefaction processes. In this study, a novel catalyst-filled wavy plate-fin heat exchanger (CFHE) is proposed to simultaneously enhance heat transfer and ortho–para hydrogen conversion under cryogenic conditions. Compared with conventional straight-fin configurations, the wavy-fin structure introduces controlled flow perturbations and increased specific surface area, thereby intensifying transport processes. Three-dimensional computational fluid dynamics (CFD) simulations, using the SST k–ω turbulence model, coupled with an ortho–para hydrogen conversion kinetic model were performed to quantitatively investigate the effects of key geometric parameters and catalyst loading on hydrogen conversion, heat transfer, and pressure drop within a Reynolds number range of 941–1577 and a temperature range of 35–20 K. Within the same CFHE configuration, the para-hydrogen fraction remains nearly unchanged without catalyst but increases significantly with catalyst loading. However, the catalyst reduces the global average Colburn j-factor by about 25%. Despite higher friction losses, the outlet–inlet temperature difference decreases to about 0.866 times that of the non-catalyst case, indicating improved temperature uniformity. A comprehensive performance index e, integrating heat transfer enhancement, flow resistance, and conversion efficiency, was introduced and optimized using a genetic algorithm. The optimized CFHE achieves an outlet para-hydrogen fraction exceeding 95% of the thermodynamic equilibrium value while maintaining hydrogen entirely in the gaseous phase to avoid catalyst deactivation. Overall, the catalyst-packed wavy channel configuration demonstrates superior conversion efficiency, enhanced thermal uniformity, and improved overall performance compared with straight-fin structures, providing quantitative design guidance for high-performance heat exchangers in cryogenic hydrogen liquefaction systems. Full article

Hydrogen has huge potential for sustainable future industries, but the formation of hydrogen boil-off gas (BOG) is a main drawback of liquid hydrogen (LH2) applications as BOG venting raises safety issues and leads to significant hydrogen loss. A promising approach for BOG recovery is a system with exchangeable cartridges filled with metal hydride (MH). Previous studies focus on the macroscopic level of the interaction between the cartridges with the boil-off sources and the consumers. A detailed investigation of the cartridge design remains necessary to assess the potential of this novel BOG recovery system. This study elaborates design concepts for the individual cartridge. A thorough material selection for suitable MH alloys is conducted and requirements for the cartridge design are derived. The key design features of the cartridges are determined and summarized in a morphological box. Four explicit design concepts are elaborated and illustrated. These results provide the baseline for upcoming studies to explicitly design and manufacture an MH cartridge demonstrator for testing, assisting the transformation to an even more sustainable LH2 industry. Full article

Liquid is a fundamental requirement for life as we understand it, but whether that liquid has to be water is not known. We propose the hypothesis that ionic liquids (ILs) and deep eutectic solvents (DES) constitute a class of non-aqueous planetary liquids capable of persisting on a wide range of bodies where stable liquid water cannot exist. This hypothesis is motivated by key physical properties of ILs and DES. Many exhibit vapor pressures orders of magnitude lower than that of water and remain liquid across exceptionally wide temperature ranges, from cryogenic to well above terrestrial temperatures. These properties permit stable liquids to exist where liquid water would rapidly evaporate or freeze and outside of bulk phases as persistent microscale reservoirs—such as thin films and pore-filling droplets. In other words, ILs and DES can persist in environments without requiring oceans, thick atmospheres, or narrowly regulated climate conditions. We further hypothesize that ILs and DES could act as solvents for non-Earth-like life, based on their polar nature and the demonstrated stability and functionality of proteins and other biomolecules in ionic liquids. More speculatively, our hypothesis extends to the idea that ILs and DES could enable prebiotic chemistry by providing long-lived, protective liquid environments for complex organic molecules on bodies such as comets and asteroids, where liquid water is absent. Additionally, based on the occurrence of DES-like mixtures as protective intracellular liquids in desiccation-tolerant plants, we propose that ILs and DES might be solvents that life elsewhere purposefully evolves. We review protein and other biomolecule studies in ILs and DES and outline planetary environments in which ILs and DES might occur by discussing available anions and cations. We present strategies to advance the IL/DES solvent hypothesis using laboratory studies, computational chemistry, planetary missions, analysis of existing spectroscopic datasets, and modeling of liquid microniches and chemical survival on small bodies. Full article

In this paper, the regenerated NdFeB magnets were fabricated by Nd₈₅Al₁₅ alloy diffusion, and the influence of alloy content and diffusion temperature on the properties and microstructure was systematically studied. The recovery mechanism of magnetic properties was discussed based on the analyses using scanning electron microscope (SEM), energy dispersive spectrometer (EDS) and electron probe microanalysis (EPMA) observation. The results indicate that the coercivity (H_cj) increases significantly with both alloy addition and temperature, reaching the maximum value of 1087 kA/m (80.9% enhancement) compared with the non-diffused magnet (601 kA/m). The maximum remanence (B_r) and maximum energy product (BH_max) of the diffused magnet are 0.99 T and 184.7 kJ/m³, which are 8.8% and 5.9% lower than those (1.085 T and 196.3 kJ/m³) of the non-diffused magnet. The density and compressive strength of the diffused magnet are enhanced by 8.2% (7.25 g/cm³) and 67.47% (628 MPa), respectively. As the compensation of Nd₈₅Al₁₅ melt, the density, B_r and BH_max are improved via the liquid filling into pores. Simultaneously, the H_cj is enhanced through the repair of grain boundary defects and the formation of continuous Nd-rich phases. Full article

Tuned liquid dampers (TLDs) are widely used in structural vibration mitigation, but they are limited by their damping frequency to use as passive damping equipment. To enhance the damping performance of the conventional TLD, a unique layered tuned liquid damper (LTLD) filled with water and diesel is proposed. The interfacial wave coupling mechanism for broadband energy dissipation has not been previously explored in sloshing-type dampers. A series of frequency-sweeping tests were carried out in the laboratory to compare the vibration suppression performance of the proposed LTLD against conventional TLD. The dampers were installed on an elastic supporting structural platform (SSP) with a height of one meter, and the bottom was horizontally excited with different amplitudes and frequencies using a hexapod motion simulator. The results indicate that the LTLD showed a better damping performance than the TLD under small-amplitude excitation and achieved optimization at two peaks. The separation surface movement dissipated the liquid motion’s energy and enhanced the hydrodynamic force in the horizontal direction. However, the damping effect of the LTLD weakened when the two liquids were no longer immiscible under large-amplitude excitation. Therefore, we recommend utilizing the LTLD to improve structural damping performance when $d_{max}/L$< 0.04984. In addition, the LTLD reduced the maximum wall pressure by about 25% in the transient state under large-amplitude excitation. This study presents experimental evidence that a water–diesel LTLD achieves broadband damping through interfacial wave coupling. The stable interfacial waves enhance energy dissipation and excite new vibration mitigation frequencies, offering a novel approach to overcoming the narrow-band limitation of conventional TLD. Full article

Despite the rise in precision medicine, breast cancer management still lacks the non-invasive tools necessary to track tumor dynamics in real time. MicroRNAs (miRNAs) have emerged as strong candidates to fill this gap, particularly within the liquid biopsy framework. Their inherent stability in circulation and their ability to reflect specific molecular changes make them compelling biomarkers for clinical use. This review outlines the current state of miRNA research in breast cancer, specifically assessing their utility in early diagnosis and the prediction of patient outcomes. The focus is on a range of high-priority targets, such as miR-21, miR-155, and the miR-200 family, which have demonstrated consistent dysregulation across different molecular subtypes of breast cancer. These molecules offer a distinct advantage over traditional protein markers by providing a more precise look at tumor progression and therapeutic resistance. However, the transition from discovery to clinical practice remains blocked by technical inconsistencies. The lack of standardized protocols for RNA isolation and the difficulty in identifying reliable reference genes for normalization continue to affect reproducibility. While the potential for these biomarkers is well-documented, the field must now shift its focus toward establishing clinical reliability. Large-scale prospective validation studies are on the horizon to facilitate this implementation. All in all, international consortia and multi-center trials are required to test circulating miRNA biomarkers in real-world settings, ensuring they are feasible enough to guide routine oncological decision-making. Full article

The placement technique of resin composites may significantly influence marginal integrity, wear resistance, and operative efficiency. This in vitro study evaluated the influence of different placement techniques for a bulk-fill resin composite on marginal integrity, wear behavior, and application time. Standardized Class I cavities were prepared in extracted human molars and restored using the same bulk-fill composite (Filtek One Bulk Fill, 3M, USA) applied with four techniques: incremental placement, incremental placement with a modeling liquid (GC Modeling Liquid, GC Corp., Tokyo, Japan), bulk placement, and the stamp technique. Application time was recorded in seconds. All specimens underwent combined mechanical and thermal aging (SD Mechatronik, Germany). Marginal integrity was assessed three-dimensionally using micro-computed tomography, while surface wear was quantified through computer-based digital analysis with OraCheck software (Dentsply Sirona, Germany). Bulk placement exhibited significantly higher microleakage scores than the other techniques while demonstrating the shortest application time. Incremental placement, incremental placement with modeling liquid, and the stamp technique showed comparable microleakage results (p > 0.05). Although the use of modeling liquid did not increase microleakage, it resulted in significantly greater wear. Placement technique significantly influences marginal integrity, wear behavior, and application time of bulk-fill composite restorations. Full article

To support the integration of high shares of renewable energy and enhance the operational flexibility of thermal power systems, thermosyphon have been considered as promising high-efficiency heat transfer components for thermal energy storage applications. In this study, a water-based thermosyphon motivated by molten-salt thermal energy storage scenarios is investigated numerically to clarify its internal heat-transfer behavior under different operating conditions. A two-dimensional CFD model is established based on the Volume-of-Fluid (VOF) multiphase approach coupled with the Lee phase-change model. The effects of heating power (3.5–5.0 kW) and liquid filling ratio (25–40%) on wall temperature distribution and thermal resistance characteristics are systematically analyzed. The results indicate that increasing the filling ratio improves the uniformity of the evaporator wall temperature, and a filling ratio of 40% leads to a relatively favorable liquid distribution and the lowest total thermal resistance within the investigated range. The evaporator thermal resistance exhibits a “decrease–increase” trend with heating power and reaches a minimum value of 1.019 × 10⁻⁴ K/W at 4.5 kW, while the condenser thermal resistance decreases monotonically with in-creasing heating power. This study provides comparative numerical insights into the coupled effects of heating power and filling ratio on thermosyphon performance, offering a reference for the component-level design and parameter selection of heat pipe heat exchangers in molten-salt-related thermal energy storage systems. Full article

To investigate the improvement effect of sodium polyacrylate on the shear strength of silty clay, this study explores the curing treatment of silty clay using sodium polyacrylate. Liquid-plastic limit tests and triaxial shear tests were conducted to examine the impact of sodium polyacrylate on the liquid-plastic limits and shear strength of silty clay, as well as to determine the optimal dosage. Additionally, low-field nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) tests were performed to further reveal the micro-mechanism of sodium polyacrylate’s action. The results show that as the sodium polyacrylate content increases, the liquid-plastic limits of silty clay increase significantly. Compared to untreated samples, when the sodium polyacrylate content is 7%, the liquid limit and plastic limit increase by 132.7% and 167.3%, respectively. Meanwhile, the cohesion of the modified samples increases with the sodium polyacrylate content, while the internal friction angle first increases and then decreases. When the sodium polyacrylate content rises from 0% to 7%, the cohesion and internal friction angles of the modified samples increase by 522.9% and 70.6%, respectively. Through comprehensive analysis of the experimental results, it was determined that the optimal dosage of sodium polyacrylate is 5%. Microstructural analysis indicates that sodium polyacrylate interacts with soil particles through hydrogen bonding and ion bridging, filling the pores between particles and encapsulating their surfaces. This improves the pore structure of the soil and enhances the bonding strength between particles. This study provides a theoretical basis for the application of sodium polyacrylate in soft soil improvement. Full article