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In this work, we propose a linear machine learning force matching approach that can directly extract pair atomic interactions from ab initio calculations in amorphous structures. The local feature representation is specifically chosen to make the linear weights a force field as a force/potential function of the atom pair distance. Consequently, this set of functions is the closest representation of the ab initio forces, given the two-body approximation and finite scanning in the configurational space. We validate this approach in amorphous silica. Potentials in the new force field (consisting of tabulated Si–Si, Si–O, and O–O potentials) are significantly different than existing potentials that are commonly used for silica, even though all of them produce the tetrahedral network structure and roughly similar glass properties. This suggests that the commonly used classical force fields do not offer fundamentally accurate representations of the atomic interaction in silica. The new force field furthermore produces a lower glass transition temperature (Tg ∼ 1800 K) and a positive liquid thermal expansion coefficient, suggesting the extraordinarily high Tg and negative liquid thermal expansion of simulated silica could be artifacts of previously developed classical potentials. Overall, the proposed approach provides a fundamental yet intuitive way to evaluate two-body potentials against ab initio calculations, thereby offering an efficient way to guide the development of classical force fields. [ABSTRACT FROM AUTHOR]

The article explores the atomisation of a droplet levitated acoustically, detailing the intricate processes of deformation and breakup. Various instabilities like Faraday, Kelvin-Helmholtz, Rayleigh-Taylor, and Rayleigh-Plateau are observed during the breakup, supported by visual evidence. The study provides insights into droplet dynamics, stretching, thinning, primary and secondary atomisation, and the influence of factors like droplet size and acoustic frequency on the breakup process. The research delves into different modes of breakup such as umbrella, bag, bubble, and multi-stage breakup, shedding light on potential applications in large-scale atomizers utilizing acoustic fields. [Extracted from the article]

To investigate the crack propagation mechanisms in low-permeability coal seams induced by liquid CO2 phase change blasting under different blasting pressures, this research presents an experimental study conducted on a small liquid CO2 phase change blasting test system. The failure mode, crack morphology, and distribution characteristics of the coal rock model specimens under different liquid CO2 phase change blasting pressure were revealed, analyzing the crack shapes and expansion process. The results show that with increasing blasting pressure, both the number and complexity of cracks significantly increase under liquid CO2 phase change blasting, evolving from simple linear cracks to more complex multi-directional networks. Furthermore, the process of crack generation and expansion during liquid CO2 phase change blasting in coal and rock is controlled by the interaction of shock waves and quasi-static stress resulting from high-pressure CO2 phase transition in the borehole. Cracks form in distinct zones: the broken zone, where shock waves cause severe crushing near the borehole; the crack zone, where quasi-static tensile stress drives crack propagation. Higher confining and CO2 blasting pressures increase crack propagation. The research results offer valuable insights for optimizing blasting design in liquid CO2 phase change fracturing. [ABSTRACT FROM AUTHOR]

The article in the Journal of Fluid Mechanics explores predicting the initial microlayer thickness in nucleate boiling through the Landau-Levich theory. The model proposed in the study accurately estimates the microlayer thickness by treating it as a Landau-Levich film, aligning well with experimental data. The research sheds light on microlayer dynamics crucial for boiling heat transfer, addressing discrepancies in previous theories and experimental findings. By offering a straightforward and precise prediction of the initial microlayer thickness, the model presented in the text enhances understanding of microlayer formation during nucleate boiling and its impact on heat transfer processes. [Extracted from the article]

Bionic robots have great potential in healthcare, rescue, and surveillance. However, most soft actuators can only realize one or two deformation modes, which largely limit the application in complex environments. This study develops electric/Infrared (IR) light/magnetic multi‐field coupling soft actuators by combining liquid crystal elastomers (LCE), liquid metal (LM) and magnetic Ecoflex (Mecoflex). Originated from the synergistic effect of the differed thermal expansion and the liquid crystal phase transition, the actuator can realize outstanding large deformations (bending angle > 300°) at ultra‐low voltages (1.0 V). In addition, by designing the molecular orientation in the LCE layer and programming the magnetization in the Mecoflex layer, the bending or helical bending deformations can be controlled under electric/magnetic and IR light/magnetic coupling actuation. Based on the complex deformation capability, bionic climbing plants and two kinds of quadrupedal robots are developed. With the structural design of the quadrupedal robots, they can flexibly switch deformations to pass through complex environments by controlling the externally applied coupling fields, which demonstrates their broad potential in practical applications. [ABSTRACT FROM AUTHOR]

In this paper, the design and implementation of a temperature-controlled recirculating flat jet system for liquid crystals (LCs)-based experiments are presented. In these experiments, the target liquid is usually exposed to medium to high laser fluences, possibly resonant with specific excitation, thus resulting in a change of local temperature and sudden degradation. To overcome this problem, each laser pulse must interact with a new volume of liquid, preferably with flat surfaces, while avoiding the use of substrates. A well-established solution consists of impinging two identical laminar jets that force the liquid into a radial expansion perpendicular to the plane formed by the jets, resulting in a consecutive chain of flat sheets bound by thick rims. In this context, LCs pose several challenges considering their viscosity, non-Newtonian behavior, and mesophase nature. Here, a precise control of temperature, thus mesophase, and pressure is demonstrated enabling the use of LCs in an impinging jet system. In particular, the system presented here delivers stable fluid chains of different sizes and thicknesses. The viscosity and non-Newtonian behavior of the LCs have a significant impact on the thickness of the chains as a function of the nozzle inner diameter, impinging angle, and radial distance from the impinging point. The flow rate, on the other hand, primarily affects the width and length of the liquid sheet. [ABSTRACT FROM AUTHOR]

Cross-zero expansion coefficient Rayleigh–Bénard–Marangoni (CRBM) convection refers to the convective phenomenon where thermal convection with stratified positive and negative expansion coefficients in a liquid layer is coupled with the Marangoni convection. In the Bénard convection, fluids with a cross-zero expansion coefficient contain a neutral expansion layer where the expansion coefficient (α) is zero, and the local buoyancy-driven convection is coupled with the Marangoni convection, leading to unique flow instability phenomena. This paper uses linear stability theory to analyze the CRBM convection in a horizontal liquid layer under a vertical temperature gradient and performs numerical calculations for fluids under different Bond numbers (Bd) in both bottom-heated and bottom-cooled models, obtaining the critical destabilization conditions and modes. In the bottom-heated model, different combinations of buoyancy instability mechanism (BIM), tension instability mechanism, and coupled instability mechanism (CIM) appear depending on the dimensionless temperature for the neutral expansion layer ( T α 0 ) and the Bd. In the bottom-cooled model, two mechanisms occur according to the variation of T α 0 : BIM and CIM. [ABSTRACT FROM AUTHOR]

The 1773 K phase diagram of the TiO 2 –SiO 2 –CaO-10 wt%Al 2 O 3 -7.5 wt%MgO system was constructed experimentally using the quenching method, focusing on the composition range of high TiO 2 content. The obtained isothermal section contains four phase fields: the liquid phase field, the primary phase field of pseudo-brookite, the primary phase field of perovskite, and the liquid + perovskite + pseudo-brookite phase field. The pseudo-brookite particle precipitated in its primary phase field is more suitable for the efficient selective enrichment and separation of titanium resources. The increase of MgO from 5 % to 7.5 % in the TiO 2 –CaO–SiO 2 -10 wt%Al 2 O 3 –MgO system leads to a decrease of the liquidus temperature and an expansion of the liquid + pseudo-brookite + perovskite phase field. The increase of MgO promotes the enrichment of TiO 2 into the pseudo-brookite phase and reduces the TiO 2 level in the glass phase. [ABSTRACT FROM AUTHOR]

Simple Summary: Cancer presents a significant global health challenge, particularly in ageing populations, emphasising the importance of early detection to facilitate personalised care and optimised treatment to improve patient outcomes. Liquid biopsy offers a minimally invasive approach for isolating and profiling circulating tumour-derived components with potential for cancer diagnosis and monitoring. Tumour-derived extracellular vesicles are secreted from cancer cells and harbour cancer-specific cargo with enhanced stability within the blood, indicating their potential utility as a diagnostic biomarker. However, translating extracellular vesicle biomarkers into clinical practice faces significant hurdles. This critical review evaluates the current landscape, challenges, and future directions of tumour-derived extracellular vesicle biomarkers, proposing strategies to overcome translational barriers. The successful integration of a liquid biopsy-based assessment of tumour-derived extracellular vesicles could transform cancer diagnostics and management. Cancer continues to impose a substantial global health burden, particularly among the elderly, where the ongoing global demographic shift towards an ageing population underscores the growing need for early cancer detection. This is essential for enabling personalised cancer care and optimised treatment throughout the disease course to effectively mitigate the increasing societal impact of cancer. Liquid biopsy has emerged as a promising strategy for cancer diagnosis and treatment monitoring, offering a minimally invasive method for the isolation and molecular profiling of circulating tumour-derived components. The expansion of the liquid biopsy approach to include the detection of tumour-derived extracellular vesicles (tdEVs) holds significant therapeutic opportunity. Evidence suggests that tdEVs carry cargo reflecting the contents of their cell-of-origin and are abundant within the blood, exhibiting superior stability compared to non-encapsulated tumour-derived material, such as circulating tumour nucleic acids and proteins. However, despite theoretical promise, several obstacles hinder the translation of extracellular vesicle-based cancer biomarkers into clinical practice. This critical review assesses the current prospects and challenges facing the adoption of tdEV biomarkers in clinical practice, offering insights into future directions and proposing strategies to overcome translational barriers. By addressing these issues, EV-based liquid biopsy approaches could revolutionise cancer diagnostics and management. [ABSTRACT FROM AUTHOR]

In this study, a novel approach for enhancing the rapid spreading of free liquid film on lithium niobate (LiNbO3) substrate under megahertz (MHz) surface acoustic wave (SAW) excitation is presented by treating it with surfactants. Through the design of a specific interdigital transducer structure, it was discovered that exciting the SAW at a frequency of 32.3 MHz can achieve optimal spreading performance for water droplets on the surface of surfactant-treated LiNbO3 substrate. The maximum average velocity reaches 1.76 mm/s at position P2 = 1250 μm in the water film front, and the stable film spreading speed shows a 204.9% increase compared to the existing research. Simultaneously, through the investigation of the spreading experiment phenomenon of silicone oil and de-ionized water droplets at varying frequencies, we have discovered the dynamic mechanism of "reverse phase" propagation in liquid film for the first time. This entails that the advancing edge of the wetting film demonstrates a spreading motion law that is opposite to the traditional spreading phenomena, with the spreading velocity in the central exceeding that on both sides. Our research demonstrates that this microfluidic device developed by SAWs enhances the spreading efficiency of the free films, enabling rapid expansion of the target liquid to form a high-surface area film layer. This advancement holds promise for overcoming the limitations of low sensitivity and short response time in the field of rapid pathological diagnosis in contemporary medicine. [ABSTRACT FROM AUTHOR]

Due to the significant pollution caused by the current extraction technology for deep coalbed methane (CBM), we propose the application of anhydrous cracking technology—liquid nitrogen cyclic freeze–thaw technology—to crack deep coal seams to achieve the release and extraction of coal bed methane. The self-made system for applying confining pressure is employed to simulate the deep coal seam in coal sample testing. Subsequently, the effect of joint structure with different angles of coal surface and bedding on the liquid nitrogen cyclic freeze–thaw process is evaluated. The investigation study identifies the damage patterns of the coal sample against the sole factor and coupling effect of confining pressure and joint angle. The findings reveal a clear impact of the cyclic freeze–thaw of liquid nitrogen on the expansion of deep coal seams. The application of appropriate inclined joints, combined with confining pressure, significantly minimizes the crushing time of coal samples, with the maximum expansion rate occurring at joints with a bedding angle of 45°±5°. This study provides vital theoretical support for the green and efficient exploitation of deep CBM. Practical Applications: The results of this study indicate that the waterless hydraulic fracturing technology—liquid nitrogen cyclic freeze–thaw technology—is highly suitable for coalbed methane extraction in deep, low-permeability coal seams, leading to increased gas recovery. The deeper the coal seam, the more pronounced the effects. Moreover, this technology does not cause environmental pollution. It specifically targets the pores, fractures, and joint structures within the coal, preserving the overall framework of the coal and preventing tunnel instability, thereby enhancing coal mining safety. Additionally, under the influence of liquid nitrogen cyclic freeze–thaw, joints at different angles exhibit varying rates of expansion. Joints extending at a 45° angle to the coal's bedding planes show the most rapid expansion, indicating that this orientation stores the maximum amount of coalbed methane postliquid nitrogen freeze–thaw. This pattern can be scientifically applied in the actual engineering design of extraction wells. The experimental results can provide a theoretical basis for guiding the on-site application of deep coal seam permeability enhancement and green coalbed methane extraction technology, thereby reducing environmental pollution. [ABSTRACT FROM AUTHOR]

Convective heat transport in permeable media has been widely modeled using the local thermal non-equilibrium (LTNE) model. The majority of earlier LTNE-based models take temperature interactions between the fluid and solid phases into consideration. The present investigation delves into the intricate dynamics of Darcy–Rayleigh–Bènard (DRB) convection occurring within a liquid layer situated above a porous layer, wherein thermal gradients and heat generation play a pivotal role. This research examines the effects of many types of thermal gradients, including parabolic, step function (SF), linear, piecewise linear heated from below (PLHB), inverted parabolic, and piecewise linear cooled from above (PLCA). A fluid layer sits on top of a porous layer in the composite layer that makes up the system. The porous medium has achieved complete saturation with the identical fluid. The observed system demonstrates the manifestation of LTNE phenomena. Furthermore, the composite layer is constrained horizontally due to the presence of adiabatic stiff peripheries. The explanation to the aforementioned issue is obtained by employing the perturbation approach via analytical methodologies. The ongoing research is focused on exploring various physical parameters in order to examine the underlying physical implications that uphold the phenomenon of LTNE, employing the utilization of diagrammatic representation. A juxtaposition is drawn between the results derived from manipulating various constraints, including the temperature expansion ratio of the liquid phase, the corrected internal Rayleigh numbers, the thermal ratio, the diffusivity ratio of the liquid layer, and the permeable layer, within the framework of the LTNE configuration, and those obtained within the Local Thermal Equilibrium (LTE) regime. The depth ratio is a key factor in the onset of DRB convection, and higher depth ratio values which indicate porous layers that predominate in composite layered systems have a noticeable impact on all variables under investigation. [ABSTRACT FROM AUTHOR]

Text of abstract in source Calibri and size 10 pt. The abstract can be English, French or Spanish. This article aims to discuss the importance of water for the socioenvironmental resistance of peasants in the Cerrado of Goiás and the pressure represented by the formation of Liquid Territories in Goiás. For peasants and traditional communities, water is life and a guarantee of staying in the place, caused by a "symbiosis" with the environment. For agribusiness, water is just an available and abundant resource that should be used as a product. But the more the resource (product) runs out, the greater the occurrence of conflicts due to access to water. Based on the theoretical concept of Environmental Geography, the construction of a dialectical narrative is based, that the formation of liquid territories, arising from the extreme capitalization of the use of water, contrasts with the climatic conditions of the Cerrado and the maintenance of life in this territory. Thus, the article is divided into three fundamental topics: the depletion of water resources in the Cerrado; the formation of liquid territories with the expansion of central pivots and dams of Small Hydroelectric Plants and, finally, the need for water for the reproduction of cerradeiros peoples, as well as the importance of the latter for the conservation of the Cerrado. [ABSTRACT FROM AUTHOR]

Students often find it difficult to understand phenomena of everyday life that occur in the natural world, such as the phenomenon of expansion and contraction of liquids, in which there are many misinterpretations. To address this difficulty, this paper suggests another perspective on the didactic approach based on Mixed Reality, the attunement of the two worlds, the virtual and the real, and examines its effectiveness in teaching the phenomenon of fluid expansion. The main pillar of the educational process is teachers and the practices they use in the teaching process. For this reason, the sample of this survey consisted of 54 University students and prospective elementary education teachers. The mixed research approach was followed to collect the data. Through a Mixed Reality environment, using HoloLens 2, students followed a well-structured scenario and worksheets and observations to investigate the phenomenon of expansion/contraction of different fluids. The results demonstrate that through the interaction and direct feedback of the Mixed Reality environment, students gained a deeper understanding of the phenomenon. At the same time, the device was characterized as a particularly useful educational tool that should be accessible to all students for a better familiarization with complex scientific data. [ABSTRACT FROM AUTHOR]

We propose a simulation method for two‐dimensional (2D) crossed‐type exit pupil expansion based on polarization volume grating (PVG) applied in diffractive waveguide holographic display. The functions of turning and decoupling of the PVG are realized through two continuous Bragg regions, and the spatial director distribution of liquid crystal is combined with RCWA to model its diffractive characteristics and ray tracing simulation. [ABSTRACT FROM AUTHOR]

We analyze the field‐of‐view (FoV) limitations in a single‐layer, full‐color waveguide‐based augmented reality display, revealing key influences from the waveguide's refractive index, exit pupil expansion (EPE) scheme, and combiner's angular response. Based on these analyses, we propose an optimized butterfly EPE scheme with gradient‐pitch polarization volume gratings (PVGs), achieving a theoretical diagonal FoV of 54.06° with a 16:10 aspect ratio. [ABSTRACT FROM AUTHOR]

The structure and properties of materials are determined by a diverse range of chemical bond formation and breaking mechanisms, which greatly motivates the development of selectively controlling the chemical bonds in order to achieve materials with specific characteristics. Here, an orientational intervening bond‐breaking strategy is demonstrated for synthesizing ultrathin metal–organic framework (MOF) nanosheets through balancing the process of thermal decomposition and liquid nitrogen exfoliation. In such approach, proper thermal treatment can weaken the interlayer bond while maintaining the stability of the intralayer bond in the layered MOFs. And the following liquid nitrogen treatment results in significant deformation and stress in the layered MOFs' structure due to the instant temperature drop and drastic expansion of liquid N2, leading to the curling, detachment, and separation of the MOF layers. The produced MOF nanosheets with five cycles of treatment are primarily composed of nanosheets that are less than 10 nm in thickness. The MOF nanosheets exhibit enhanced catalytic performance in oxygen evolution reactions owing to the ultrathin thickness without capping agents which provide improved charge transfer efficiency and dense exposed active sites. This strategy underscores the significance of orientational intervention in chemical bonds to engineer innovative materials. [ABSTRACT FROM AUTHOR]

As a new type of proton conductor, metal–organic frameworks (MOFs) have attracted much attention because of their superior properties over conventional materials, such as the modifiability of framework, reversibility of coordination bond, high specific surface area, and porosity. It is predicted that the proton conductivities of MOFs can be improved by hole expansion and ionic liquid introduction. In this work, HKUST‐1 and LP‐HKUST‐1 were prepared, which were filled with different proportions of N‐methylimidazole triflate (MIM‐CF3SO3) to prepare composite materials MIM‐CF3SO3@HKUST‐1‐100% and MIM‐CF3SO3@LP‐HKUST‐1‐x (x = 25%, 50%, 75% and 100%). A total of seven kinds of materials were synthesized. The proton conductivities of all the materials at 75% RH were tested from 303 to 353 K. In this environment, MIM‐CF3SO3@LP‐HKUST‐1‐100% shows excellent proton conductivity (σ = 0.341 S·cm−1 at 353 K, 75% relatively humidity [RH]), being 7060 times that of HKUST‐1, and reaches the peak value of MOF family in recent years. Then, the conductivities of parts of the materials were tested in extreme environments, such as in high‐humidity environment (303–353 K, 100% RH), high‐temperature environment (373–423 K, N2 atmosphere), and low‐temperature environment (253–283 K, 75% RH). The results show that under all conditions above, the proton conductivity of MIM‐CF3SO3@LP‐HKUST‐1‐100% is the best, up to 0.341 S·cm−1 at 353 K and 75% RH, 0.179 S·cm−1 at 353 K and 100% RH, 1.31 × 10−3 S·cm−1 at 283 K and 75% RH, and 2.31 × 10−4 S·cm−1 at 423 K and N2 atmosphere, indicating that proton conductivity of HKUST‐1 is improved by hole expansion and ionic liquid introduction. Finally, the stability test showed that MIM‐CF3SO3@LP‐HKUST‐1‐100% was stable in all environments above. Moreover, the conductive mechanism of HKUST‐1 before and after introduction of ionic liquids was also discussed, providing a theoretical basis for the enhancement of proton conductivities of MOFs using ionic liquid introduction and hole expansion. [ABSTRACT FROM AUTHOR]

When microdroplets with quasi‐spherical contact angles coalesce together on a low‐adhesion substrate, the capillary‐inertial expansion of the liquid bridge induces a dramatic out‐of‐plane jumping event due to symmetry breaking. From the onset of merging, droplet jumping initiates after a capillary‐inertial time scale of tci∼1–100 ${t}_{\text{ci}}\sim 1\mbox{--}\,100$ μs with characteristic jumping speeds of order vj∼0.1 ${v}_{{\rm{j}}}\sim 0.1$ m/s. This coalescence‐induced jumping‐droplet effect is most commonly observed among a population of growing dew droplets on a superhydrophobic condenser, but can also occur by colliding deposited droplets together or during droplet sliding on fog harvesters. In this review, we cover the historical development of capillary‐inertial jumping droplets, summarize the decade‐long effort to rationalize the ultra‐low energy conversion efficiency and critical droplet size of the phenomenon, and then present 15 variations on a theme of jumping. Capillary‐inertial jumping droplets are not only a visceral illustration of the surprising power of surface tension at the microscale but they also have the potential to enhance phase‐change heat transfer, enable self‐cleaning surfaces, combat frost formation, harvest energy, and govern the rate of disease spread for wheat crops. [ABSTRACT FROM AUTHOR]

The relationships between materials processing and structure can vary between terrestrial and reduced gravity environments. As one case study, we compare the nonequilibrium melt processing of a rare-earth titanate, nominally 83TiO2-17Nd2O3, and the structure of its glassy and crystalline products. Density and thermal expansion for the liquid, supercooled liquid, and glass are measured over 300–1850 °C using the Electrostatic Levitation Furnace (ELF) in microgravity, and two replicate density measurements were reproducible to within 0.4%. Cooling rates in ELF are 40–110 °C s−1 lower than those in a terrestrial aerodynamic levitator due to the absence of forced convection. X-ray/neutron total scattering and Raman spectroscopy indicate that glasses processed on Earth and in microgravity exhibit similar atomic structures, with only subtle differences that are consistent with compositional variations of ~2 mol. % Nd2O3. The glass atomic network contains a mixture of corner- and edge-sharing Ti-O polyhedra, and the fraction of edge-sharing arrangements decreases with increasing Nd2O3 content. X-ray tomography and electron microscopy of crystalline products reveal substantial differences in microstructure, grain size, and crystalline phases, which arise from differences in the melt processes. [ABSTRACT FROM AUTHOR]

A negative DC high voltage is used to generate plasma at ambient condition. Self‐organized patterns (SOPs) are formed on the surfaces of the liquid anodes. With increased current or gap distance or reduced gas flow rate, the diameters of SOPs increase and SOPs become more complex, coinciding along with an increases of gas temperature and plasma radius and a decrease of electron density. Both plasma expansion and liquid evaporation in terms of gas temperature, lead to a drop of electron density and pattern formation. Our research elucidates the correlation between SOPs evolution and plasma properties and clarifies the physical process of SOPs formation based on the interaction between atmospheric pressure plasma and liquid anodes. [ABSTRACT FROM AUTHOR]

Expanding emulsions with liquid CO2 facilitates the creation of aerosols with an average droplet diameter in the low micrometer size range, which is challenging with conventional atomizers. The droplet formation process of the expansion of high‐pressure emulsions was investigated using a plain‐orifice atomizer and different swirl nozzles. The local droplet size and droplet velocities were measured and used to estimate the local Weber number and thus infer the droplet size reduction. Measurements of the local mass concentration in the aerosol showed that, for the swirl nozzle, the highest concentration was found outside of the central axis, indicating radial momentum generated by the swirl nozzle. Furthermore, it was shown that the type of expansion nozzle used has an influence on the resulting median droplet size in the aerosol. For a water mass load of 0.01, the median droplet diameter was reduced from 8 to 3 μm by increasing the swirl number from 0.01 to 0.1. [ABSTRACT FROM AUTHOR]

Cryogenic supercritical hydrogen storage technology is a high-density physical hydrogen storage method, which is a highly promising hydrogen storage approach. However, existing research has mainly focused on the development of storage devices for cryogenic supercritical hydrogen, with limited research on the cooling process of supercritical hydrogen. Therefore, a novel cooling process for cryogenic supercritical hydrogen production based on helium expansion cycle with liquid nitrogen (LN 2) pre-cooling is proposed in this paper. In this process, after being compressed and cooled in multiple stages, the feed hydrogen is pre-cooled by LN 2. Then, cryogenic supercritical hydrogen (10 MPa, −235.15 °C, 63.36 g/L) is obtained by helium multi-stage expansion refrigeration. The process is simulated by Aspen HYSYS and optimized by genetic algorithm (GA) to obtain lower specific energy consumption (SEC). Thermodynamic analyses are conducted to evaluate the process. And compared with the conventional hydrogen liquefaction process, the results show that the proposed process is reasonable and superior. The SEC 0 , figure of merit (FOM), and the total exergy loss of the system are 5.432 kWh/kg H2 , 43.88%, and 289.69 kW respectively. This study indicates that the proposed process has significant implications for the hydrogen industry and provides valuable information for cryogenic supercritical hydrogen storage systems. • A novel high-density cryogenic supercritical hydrogen storage system is proposed. • Twelve key variables in the process are optimized to reduce the energy consumption. • The process has higher exergy efficiency than conventional LH 2 plants. • The volume storage density of hydrogen can reach 63.36 kg/m3 in the system. [ABSTRACT FROM AUTHOR]

To investigate the infiltration mechanism of material liquid and the expansion and deformation characteristics of tobacco leaves in the casing process, a mathematical model of heat and mass transfer in the process of tobacco leaf casing based on the continuity theory and elastic theory of porous media is built. COMSOL software enables the realization of multi-physical field coupling in the process of casing. An analysis is made of the changes and the influences of temperature, material liquid infiltration rate as well as the expansion and deformation of tobacco leaves in the casing process. The results show: COMSOL software simulating the casing process of tobacco leaves, the peak temperature of leaves is 49.25 °C, the optimal casing environment temperature 65 °C, the final infiltration rate of material liquid 19. 85%, and the final leaf expansion rate 8.6%; the temperature change and material liquid infiltration of tobacco leaves mainly start when the material liquid are beaten onto the leaves; the moisture stress generated by the diffusion of the liquid inside the blade is significantly greater than the thermal stress generated by the temperature change, indicating that the diifusion of the liquid exerts a greater impact than the temperature on the expansion and deformation of the tobacco leaves; the maximum equivalent stress of tobacco leaves occurs at about 15 s after the casing begins, and in the part beaten by the liquid, revealing the expansion and deformation enlarge the tobacco leaf skeleton and the diifusion channel of liquid as well. The expansion and deformation during the tobacco leaf casing process positively affect the diifusion of material liquid, and the distribution of material liquid insiie tobacco leaves is the main factor which influences the uniform casing. This study optimizes the tobacco leaf casing process and provides a solid theoretical basis for digital production of cigarettes. [ABSTRACT FROM AUTHOR]

Cold clusters of molecular hydrogen were created using a pulsed nozzle. The thermodynamical states of the clusters were characterized by measuring the cluster beam velocity and the laser-induced fluorescence (LIF) spectra of embedded molecules. Two distinct velocity components were identified in the beam that originates from different clustering mechanisms. The fast velocity component corresponds to the expansion of H2 from the gas phase, while the slow velocity component corresponds to the expansion from the liquid phase. The velocity distribution of these two components showed no significant difference between the expansions of para and normal hydrogen. In this study, LIF spectroscopy of single Mg-phthalocyanine molecules embedded in the H2 clusters consisting of 105 H2 molecules was used to investigate the properties of the fast component. The observed peak frequencies of the LIF signals, compared to those observed in helium droplets, were used to infer the possible presence of the liquid phase in the fast component of the H2 clusters below 5 K. The shift, linewidth, and splitting in the spectra, which strongly depend on the ortho/para ratio, are attributed to the local configurations of hydrogen in the vicinity of the probe molecules. [ABSTRACT FROM AUTHOR]

The anisotropy of molecular polarizability in liquid crystals is linked to the birefringence in these substances. The classic methods to compute the polarizabilities of liquid crystals assume an average number density of molecules that is equal in all directions. In the present work, a new model is proposed for the anisotropic molar polarization based on a virtual anisotropy of the number density of molecules in the liquid-crystalline material. This new strategy hence allows for the computation of both the anisotropic polarizabilities and the anisotropic thermal-expansion coefficients of liquid crystals. The model is applied to the liquid crystals 4-n-pentyl-4′-cyanobiphenyl and N-(4-methoxybenzylidene)-4-butylaniline, yielding polarizabilities similar to those reported for these materials. For these nematic liquid crystals, the results imply the existence of a positive thermal-expansion coefficient in the direction perpendicular to the director vector throughout the entire nematic temperature range and a negative thermal-expansion coefficient parallel to the director vector near the temperature of the nematic–isotropic transition. At the isotropization temperature, there exists divergent and critical behavior of the anisotropic thermal-expansion coefficients, consistent with the typical discontinuity of volume in first-order transitions. [ABSTRACT FROM AUTHOR]

Hydrate risk management is critically important for an energy industry that continues to see increasing demand. Hydrate formation in production lines is a potential threat under low temperature and high-pressure conditions where water and light gas molecules are present. Here, we introduce a 1-inch OD single-pass flow loop and demonstrate the Joule-Thomson (JT) expansion of a methane-ethane mixture. Initially, dry gas flowed through the apparatus at a variable pressure-differential. Larger pressure differentials resulted in more cooling, as predicted by standard thermodynamic models. A systematic deviation noted at higher pressure differentials was partially rectified through corrections incorporating heat transfer, thermal mass and kinetic energy effects. A wet gas system was then investigated with varying degrees of water injection. At the lowest rate, hydrate plugging occurred close to the expansion point and faster than for higher injection rates. This immediate and severe hydrate plugging has important implications for the design of safety relief systems in particular. Furthermore, this rate of plugging could not be predicted by existing software tools, suggesting that the atomization of liquids over an expansion valve is a critical missing component that must be incorporated for accurate predictions of hydrate plug formation severity. [ABSTRACT FROM AUTHOR]

Background: Airtankers are able to drop volumes of liquid (suppressant or fire retardant) varying from less than 1 m3 to several tens of cubic metres directly on a fire or with the objective to form barriers of retardant to stop or reduce fire propagation. Aims: The objective of this work is to demonstrate that Computational Fluid Dynamics can be used to provide a deep understanding of liquid fragmentation and dispersion when liquid is dropped from an aircraft. Methods: A numerical investigation based on the Volume of Fluid method is used for the analysis of airtanker performance and applied here to the biggest airtankers used in Europe: the Canadair CL-415 and Dash-8. Key results: Numerical simulations are used to provide an accurate description of tank discharge as well as to study liquid ejection, fragmentation and atomisation in air. From the results, the vertical penetration and lateral expansion of the liquid are described using simple modelling. Conclusions: From the numerical simulation, the main characteristics of liquid atomisation and dispersion in air are described and modelled. Implications: Computational Fluid Dynamics is an efficient tool that may help to optimise airtanker performance. A numerical investigation of liquid (water and retardant) drop from Canadair CL-415 and Dash-8 airtankers is presented. Numerical simulations are reported for the tank discharge as well as for the description of the liquid cloud, characterised by vertical penetration of the liquid, its lateral expansion and the process of atomisation. [ABSTRACT FROM AUTHOR]

We presented a low-cost electronic speckle imaging method for quantifying and monitoring the moderate expansion and contraction of fluids. The system comprises the steps of recording a stack of electronic speckle patterns of the liquid under coherent light illumination, generating velocity vector fields of the temporal dynamic speckle sequence, calculating profile velocity at different temperatures of the liquid, evaluating the inertia moment (IM) of the temporal history of speckle patterns followed by the computation of the co-occurrence matrices. The results show that profile velocity at different temperatures may be used to determine the liquid's thermal state. The test evaluated speckle grain size as a potential criterion for monitoring the liquid's moderate thermal expansion and allowed for the measurement of thermal exchange between the system and its surroundings even at very low temperatures (4 °C). The experiment demonstrates the effectiveness of the laser speckle imaging technique at the macro- and micro-scale molecular dynamics levels. [ABSTRACT FROM AUTHOR]

A nonuniform temperature field can deteriorate the performance of sensors, especially those working in the field, such as an optical sensor for oil-tank ground settlement (GS) monitoring. In this case, the GS monitoring employs hydraulic-level-based sensors (HLBS), which are uniformly installed along with the oil-tank basement perimeter and are all connected by hydraulic tubes. Then, the cylinder structure of the oil tank itself can create a strong temperature difference between the sensors installed in the sunlit front and those in the shadow. Practically, this sunlight-dependent difference can be over 30 °C, by which the thermal expansion of the measuring liquid inside the connecting hydraulic tubes keeps on driving a movement and, thereby, leads to fluctuations in the final result of the oil-tank GS monitoring system. Now, this system can work well at night when the temperature difference becomes negligible. However, temperature uncertainty is generated in the GS sensors due to the large temperature difference between the sensors in the daytime. In this paper, we measured the temperature where the sensor was located. Then, we compared the results of the GS sensors with their corresponding temperatures and fitted them with two separate curves, respectively. After observing the similarity in the tendency of the two curves, we found that there was a qualitative correlative relationship between the change in temperature and the uncertainty in the sensor results. Then, a curve similarity analysis (CSA) principle based on the minimum mean square error (MMSE) criteria was employed to establish an algorithm, by which the temperature uncertainty in the GS sensors was reduced. A practical test proved that the standard deviation was improved by 73.4% by the algorithm. This work could be an example for reducing the temperature uncertainty from in-field sensors through the CSA method. [ABSTRACT FROM AUTHOR]

In single phase flows, benchmarks like the lid driven cavity have become recognized as fundamental tests for newly developed computational fluid dynamics, CFD, codes. For multiphase free surface flows with variable surface tension, the presently studied pool with isothermal sidewalls is suggested as it is the simplest domain where Marangoni effects can dominate. It was also chosen due to its strange sensitivity to the initial setup which is discussed at length from a chosen number of 'scenarios'. It was found that the fluid interface can reverse deformation by a change in the top boundary condition, the liquid equation of state, and the gravity level. For the top boundary condition, this reversal is due to vapor expansion within the closed volume, creating an additional convection mechanism. Not only does the interface reverse, but the peak height changes by more than an order of magnitude at the same Marangoni number. When including gravity, the peak velocity can increase significantly, but it can also cause a decrease when done in combination with a change in the top wall boundary condition. Finally, thermal expansion of the liquid phase causes the peak velocity to be reduced, with additional reductions from the gravity and top wall condition. The differences in each scenario could lead to significant errors in analyzing a practical application of Marangoni flows. Therefore, it is important to demonstrate that a new CFD code can not only resolve Marangoni convection, but also has the capability to resolve the scenario most relevant to the application at hand. [ABSTRACT FROM AUTHOR]

Ensuring that building occupants are safe from the myriad potential hazards in process facilities involves many challenges. Often, a facility siting plan is the result of several disparate studies, conducted years apart, and stitched together to try to form an overall plan. This makes it difficult to find a complete representation of potential impacts on a building, or gauge how changes to operations may impact nearby buildings. Understanding all potential impacts is critical when making investment decisions regarding mitigations of facility siting risks. Many of these challenges can be addressed by creating a single map of the site using a high‐resolution satellite image embedded into a CAD file. By utilizing layering capabilities, contours from individual scenarios can be drawn on individual layers and viewed individually or used together to create an overall map to enable siting of occupied facilities. By having each potential hazard type drawn on a single map, one can quickly evaluate the potential hazards that impact a particular area and see whether a particular potential hazard is dominant. This can help in deciding where to site buildings, whether or not a building occupancy can be increased, evaluation of efficacy of risk mitigation measures, and emergency response efforts. [ABSTRACT FROM AUTHOR]

The present study addresses the expansion of pressurized liquid R-290 through a 1.2 mm diameter capillary tube and its subsequent motion through a metastable condition entailing a change of phase through flashing phenomenon. The expansion of R-290 through a helical capillary tube is numerically simulated using a finite volume-based mixture model. For the simulation of the flashing phenomena, a homogeneous equilibrium approach is used. The Zwart–Gerber–Belamri model is deployed to represent mass transfer during flashing. ANSYS Fluent 2021 R2 software has been used for the numerical simulations. A series of UDF (user defined functions) are developed to read the recorded database of R-290 and perform the cavitation modeling. Bilinear interpolation is performed for determining the fluid properties at the corresponding pressure and temperature. The developed numerical model has been validated against the available numerical and experimental results. For the simulations, tubes with lengths of 1200 mm , 1500 mm , 1800 mm , 2100 mm , and 2400 mm have been considered, and the impacts of increasing length on the flow characteristics at the outlet have been determined. In this investigation, the R-290 refrigerant expands from three different condenser pressures of 16, 14, and 12 bar. Evaporator pressure is adjusted from 2 bar to 8 bar to investigate its influence on flow characteristics. The fall in evaporator pressure brings about a flow transition from subsonic to supersonic. The effects of tube length, condenser, and evaporator pressures on mass transfer rate, evaporator entry temperature, mixture quality at the evaporator entrance, and available refrigeration effects have been analyzed. [ABSTRACT FROM AUTHOR]

The industrial complexes that handle dangerous products with flammable characteristics have been the cause of great misfortunes when sudden explosions are generated, either due to mechanical failures or human negligence. The Monteverde Gas Complex (MGC), located in the province of Santa Elena in Ecuador, represents a potential risk by housing close to 105,000 m3 of precursor gases such as Propane (PPN), Butane (BTN), and LPG finished product. Therefore, an analysis of the potential threat to which the population is exposed in case of the explosion of one of the tanks with the different products they contain has been carried out, considering the closest communes to the MGC, which are Monteverde and Jambelí. Tools such as the Probit method proposed by TNO (The Netherlands Organization for Scientific Research), and the ALOHA software of the EPA (Environmental Protection Agency, USA) were used, whose combinations allowed estimating the radius of influence, which were divided into zones according to the degree of impact on the community. The results demonstrated that the community of Monteverde, despite being more than 1 km away from the CGM, is within the red zone or high influence radius that corresponds to 2000 meters for propane and butane tanks. Whitin this area, a person could have fatal third-degree burns. The calculations have been performed under ideal conditions, so it is recommended to review the attenuations generated by natural elevations of the terrain or the direction of the wind in further studies. [ABSTRACT FROM AUTHOR]

An integrated flow model was developed to simulate the fluidization hydrodynamics in a new bubble‐driven gas–liquid–solid fluidized bed using the computational fluid dynamic (CFD) method. The results showed that axial solids holdup is affected by grid size, bubble diameter, and the interphase drag models used in the simulation. Good agreements with experimental data could be obtained by adopting the following parameters: 5 mm grid, 1.2 mm bubble diameter, the Tomiyama gas–liquid model, the Schiller–Naumann liquid–solid model, and the Gidaspow gas–solid model. At full fluidization state, an internal circulation of particles flowing upward near the wall and downward in the centre is observed, which is in the opposite direction compared with the traditional core‐annular flow structure in a gas–solid fluidized bed. The simulated results are very sensitive to bubble diameters. Using smaller bubble diameters would lead to excessive liquid bed expansions and more solid accumulated at the bottom due to a bigger gas–liquid drag force, while bigger bubble diameters would result in a higher solid bed height caused by a smaller gas–solid drag force. Considering the actual bubble distribution, population balance model (PBM) is employed to characterize the coalescence and break up of bubbles. The calculated bubble diameters grow up from 2–4 mm at the bottom to 5–10 mm at the upper section of the bed, which are comparable to those observed in experiments. The simulation results could provide valuable information for the design and optimization of this new type of fluidized system. [ABSTRACT FROM AUTHOR]

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The mechanisms of picosecond pulse laser ablation in liquid are investigated in a series of large-scale atomistic simulations performed for FeNi targets irradiated in a liquid environment by picosecond laser pulses at a broad range of fluences. The simulations reveal the existence of three fluence regimes featuring different dominant mechanisms of material ejection and nanoparticle formation. These are (1) the low fluence regime, where atomic clusters and small nanoparticles form through the evaporation of metal atoms followed by condensation in a low-density region at the front of the ablation plume, (2) the medium fluence regime, where roughening and decomposition of a top part of a transient spongy structure of interconnected liquid regions leads to the formation of large nanoparticles, and (3) the high fluence regime, where the nanoparticles form primarily at the phase separation front propagating through the ablation plume cooled from the supercritical state by expansion against the liquid environment and mixing with the liquid. The generation of the largest nanoparticles is observed in the medium fluence regime, and both the maximum size of the nanoparticles and the energy efficiency of the material conversion into nanoparticles decrease upon transition to the high fluence regime. Some of the nanoparticles experience extreme quench rates and rapidly solidify under conditions of deep undercooling, yielding a population of defect-rich nanoparticles of interest for practical applications. The results of the simulations are mapped to the conditions realized within a laser spot irradiated by a beam with a Gaussian spatial profile, where different ablation regimes are activated simultaneously in different parts of the laser spot. The spatially and time-resolved maps of the transient nonequilibrium states predicted in the simulations provide a comprehensive picture of the ablation dynamics and a solid foundation for interpretation of the results of time-resolved experimental probing of the initial stage of the ablation process. [ABSTRACT FROM AUTHOR]

In horizontal-tube falling film evaporation (HFFE), the heat transfer processes inside and outside the tube interact with each other and collectively determine the overall heat transfer efficiency. To better understand this process, a three-dimensional model considering the condensation process inside the tube was built to simulate the process of HFFE. The Tanasawa model was used to calculate the evaporation flux. A novel model of non-uniform heat flux distribution was proposed for considering the coupling between heat transfer and phase transition process on the both sides of the tube. The dimensionless axial distance (L *) which represents the distance from the specific cross-section to the central axis of the liquid column is introduced to analyze of parameters distribution along the axial direction. The impact of steam quality (x), steam mass flow rate (G) inside the tube and apparent temperature difference for heat transfer (Δ T a) on film thickness (δ) and heat transfer coefficient outside the tube (h o) at L * = 0.0, 0.25 and 0.5 was investigated. The calculation parameters are as follows: 0.2 ≤ x ≤ 1.0, 2 ≤ G ≤ 6 kg/(m2·s) and 2.0 ≤ Δ T a ≤ 5.0 K. The simulation shows that δ and h outside the tube are distributed significantly inhomogeneously. As x increases from 0.2 to 1.0, the average heat transfer coefficient ( h ‾ o) at three L * increases by 9.85 %, 10.77 % and 17.95 %, which is mainly due to the expansion of liquid accumulation section and the increase in h of this section. As G increases, h ‾ o outside the tube for filmwise condensation section decreases whereas that for liquid accumulation increases. The value of h outside the tube at three L * increase with an increase in Δ T a. [ABSTRACT FROM AUTHOR]

Inspired by the unique environmental sensitivities of polysaccharides and proteins, nanocellulose (NC) and silk fibroin (SF) nanocomposite hydrogels with tailored network structures and mechanical properties were developed by varying induction methods and assembly sequences. In the optimal process, SF was first assembled along the NC template to create a unique nanobead-like structure under thermal induction, followed by crosslinking in an acetic acid coagulation bath to form a polysaccharide-protein nanocomposite hydrogel with high mechanical strength, with elastic modulus as of 62,330 G′ in Pa at only 0.25 wt% NC and 1.5 wt% SF. The introduction of carboxyl groups to NC via TEMPO-mediated oxidation and the formation of nanobead-like structures improved structure stability and significantly enhanced water retention. The NC-SF nanocomposite hydrogels exhibited excellent mechanical properties, while the derived xerogels offered outstanding liquid absorption (up to 2300 %) and retention with minimal volume expansion upon liquid binding (dissolution ratio below 5 %). These properties make them promising candidates for biodegradable, biocompatible materials in applications such as sanitary products, diapers, and hemostatic matrices. [Display omitted] [ABSTRACT FROM AUTHOR]

• The effect of jet parameters on liquid film flow behavior and heat transfer characteristics in inclined jet impingement is investigated. • The occurrence and disappearance of boiling cause the expansion and contraction of the liquid film. • The splashing rate ranges from 80 to 95 % in all conditions. • The propagation of wetting fronts exhibits anisotropy in inclined jet impingement. • A regression equation is proposed to predict the maximum Nusselt number. In this study, the flow behavior and heat transfer characteristics of the liquid film on the hot wall by inclined jet impingement are experimentally studied in detail. The effects of jet parameters, such as jet inclination angle, impingement distance, jet Reynolds number (Re j), and nozzle diameter are explored. The liquid film flow is visualized using a high-speed camera, and the surface temperature and heat flux are obtained by solving the inverse heat conduction problem. The results indicate that the liquid film shape is strongly affected by jet inclination angle but is almost unaffected by other parameters. As the inclination angle increases, the liquid film shape changes from elliptical to fusiform. In addition, the onset, enhancement, and disappearance of boiling cause the expansion and contraction of liquid film. The splashing rate is barely affected by jet parameters and remains within the range of 80–95 % under all conditions. The propagation of wetting fronts exhibits anisotropy. Except for the impingement distance, the position of wetting fronts along y -axis direction displays a high dependence on all parameters. The Re j and nozzle diameter have a significant effect on the heat flux at the impingement point and parallel flow zone, while the jet inclination angle and impingement distance only effect the impingement point. The visualization image proves that the droplet impingement pattern is the main reason for the increase in heat flux at higher impingement distances. Optimizing jet parameters can promote the wall to enter the rapid cooling stage in advance and increase maximum heat flux, thereby improving the maximum cooling capacity of the jet. Finally, an empirical equation is proposed to predict the maximum Nusselt number. [ABSTRACT FROM AUTHOR]

This study introduces a novel approach to integrating LNG cold energy into the dual mixed refrigerant (DMR) process, employing liquid air as a cold energy carrier. The DMR process is chosen for natural gas liquefaction due to its flexibility in adjusting mixed refrigerant compositions when external cold sources are utilized. Two configurations are investigated: the low-pressure liquid air (LPLA) process, which relies solely on heat exchange, and the high-pressure liquid air (HPLA) process, which involves the pressurization and expansion of liquid air. Additionally, two optimization strategies are explored: 'With Composition' (WC) optimization, which includes refrigerant composition as a variable, and 'Without Composition' (WOC) optimization, which does not. Utilizing liquid air reduces the load on the refrigeration cycle, leading to improved performance compared to the conventional DMR process. The air expansion generates additional power and cold energy, while WC optimization further reduces the flow rate of low-boiling point components, significantly lowering compression energy consumption. As a result, the DMR-HPLA-WC process achieves a 44.17 % reduction in energy consumption, an 8.7 % improvement in exergy efficiency, and a 37.63 % decrease in specific costs. • Cold energy is recovered from LNG regasification and utilized in NG liquefaction. • Air expansion generates additional power and cold energy. • Composition optimization decreases flow rates of low-boiling components. • The proposed process shows a 44.17 % reduction in energy and 37.63 % in economics. [ABSTRACT FROM AUTHOR]

Compressed air energy storage (CAES) is one of the important means to solve the instability of power generation in renewable energy systems. To further improve the output power of the CAES system and the stability of the double-chamber liquid piston expansion module (LPEM) a new CAES coupled with liquid piston energy storage and release (LPSR-CAES) is proposed. The coupled LPEM conducts suction stage B at the end of the expansion stage, ensuring stable exhaust pressure and temperature for the module. By establishing the thermodynamic and economic models of LPSR-CAES, the effect laws of key node parameters on the system performance are investigated. The results show that the heat transfer between liquid droplets and air dominates the heat transfer in LPEM. The proposed LPEM exhibits excellent isothermal performance and stability, with a maximum temperature difference of about 20 K during the cycle, and stable exhaust temperature changes within 10 K. Under the design conditions, the converted electrical efficiency, round-trip efficiency, exergy efficiency and net present value of the system are 68.31 %, 58.86 %, 66.99 % and 12.25 M$ respectively. The higher the solar supplement temperature, the more outstanding the thermal and economic performance of the system. The short-term energy storage system performance of the proposed system is more prominent. Based on the actual light data, the system can achieve 72.09 % and 69.41 % of converted electrical efficiency and exergy efficiency, respectively, at the 219th day. The results of this study provide theoretical support for the engineering application of the proposed system. • A LPSR-CAES system is proposed. • The designed LPEM has better isothermal performance and exhaust stability. • The pattern of change in system performance under actual light data is analyzed. • The design exergy efficiency and NPV of the system are 66.99 % and 12.25 M$. [ABSTRACT FROM AUTHOR]

Road tunnels constructed in complex rock strata may encounter unfavourable geological formations such as rock faults. Grouting into rock faults around road tunnels or installing flexible joints for tunnel structures have been widely used in engineering practice to improve the performance of fault-crossing road tunnels against static and seismic loads. However, flexible joints with low stiffness and likely low strength may be subjected to direct explosion loads and their performance in resisting blast loads has not been investigated. In this study, the resistance of a typical fault-crossing road tunnel to an internal Boiling Liquid Expansion Vapour Explosion (BLEVE) caused by the rupture of a 20 m3 Liquified Petroleum Gas (LPG) tank is numerically investigated. The response and residual load-bearing capacity of the fault-crossing road tunnel with and without the grouting and rubber joints under the internal BLEVE are calculated and compared. It is found that the combined measures greatly enhance the BLEVE resistance of the fault-crossing road tunnel due to the fact that grouting greatly improves the mechanical properties of the fault-affected rock mass, and the rubber joints significantly attenuate the BLEVE-induced stress wave propagation inside the tunnel lining. In addition, parametric analyses are conducted to investigate the effects of the grouting and rubber joint configurations on the BLEVE resistance of the fault-crossing road tunnel. Damage criteria considering the tunnel's residual load-bearing capacity (RLBC) are also established to evaluate the collapse risk and potential collapse zone of the fault-crossing road tunnel after being exposed to internal BLEVE. The results show that the potential collapse zones of the fault-crossing road tunnel along the longitudinal direction of the tunnel can be effectively reduced by increasing grouting thicknesses and installing narrower rubber joints. [ABSTRACT FROM AUTHOR]

Electromagnetic methods can be used to affect the solidification of metallic alloys. Combined alternating and static (DC) magnetic fields can induce pressure waves in liquid metals in a contactless manner, refining grain structure, preventing component segregation, and dispersing added particles. Here, the possibility of using a pulsed magnetic field in combination with a DC magnetic field to improve the solidification structure of metals is investigated. This enables achieving higher pressure amplitude and liquid movement within the whole crucible volume at the same power consumption. This can be a prospective way to achieve a fine-grained and a more homogeneous microstructure of metallic alloys as well as disperse added particles. In this work, analytical description of the phenomena and numerical modeling of the pressure amplitude and melt motion has been performed. A series of experiments have been carried out to demonstrate the effect of such interaction on the solidified metal microstructure. It is found that a combination of pulsed and DC magnetic fields creates strong compression and expansion of the liquid metal. Metals solidified under such interaction exhibit finer grain structure in Sn-Pb alloy and improved TiB2 particle distribution in 6061 aluminum alloy. [ABSTRACT FROM AUTHOR]

The main objective of this study is to investigate the effect of turbine inlet temperature on the transient phase of expansion cycle liquid propellant rocket engines during start. For this purpose, the non-linear differential mathematical model for 15 main components of the engine is derived, and the corresponding interaction between them is established. Afterward, the model is simulated using MATLAB Simulink, and 150 equations are solved with the Newton–Raphson method. The RL10 expansion cycle liquid propellant rocket engine is selected as a case study, and its dynamic behavior is simulated, and the results are compared with the experimental data. The simulation results showed that the present model for engine dynamic parameters, including thrust-chamber pressure, fuel, oxidizer mass flow rate, and turbo-pump speed, has less than 5% error compared to previous literatures. Using the prepared modeling software, the effect of turbine inlet temperature is studied on the engine start process. The obtained results demonstrated that inappropriate temperature profile during start transient might cause an engine malfunction while entering the nominal working regime. [ABSTRACT FROM AUTHOR]

This study is a short communication on progress made in the adaptation of conventional push-rod dilatometry for the measurement of volumetric expansion of liquid salts up to 1300 K. A new crucible design is offered as a practical solution for measurement of liquid salts by this method. Proof-of-concept measurements of the volumetric expansion of sodium chloride (NaCl) are compared to the available data in literature. Measurement of the coefficient of thermal expansion (CTE) of solid NaCl compared favorably to the available data in literature, confirming both magnitude and trend. The average CTE of NaCl (solid) was α ¯ NaCl Solid = 5.63 · 10 - 5 1 K . The volumetric expansion of liquid NaCl was measured as β NaCl Liquid ≈ 3.96 · 10 - 5 1 / K and is essentially constant from the melt point to 1300 K. The volumetric expansion produced by this method is in reasonable agreement with the available published data and previous measurements made by the authors by neutron radiographic technique. [ABSTRACT FROM AUTHOR]

This article considers a unit of a unique design created at the Joint Institute for High Temperatures of the Russian Academy of Sciences, which implements the method of a pycnometer of constant volume and variable mass. The data are obtained on the density of liquid potassium on the saturation line and on the 100 atm isobar in the temperature range 336–2030 K. The relationship between the results of the methodology implemented at the Joint Institute for High Temperatures, Russian Academy of Sciences (JIHT RAS) and measurements of the compressibility of water and steam carried out at the Moscow Power Engineering Institute (MPEI), starting with the work of V.A. Kirillina 1953, is noted. The reliability of the experimental data on the density of liquid potassium in 1976–1977 is analyzed in comparison with the results of the new, independent measurements in 1990. The position of the ideal, as in a rarefied gas, coefficient of thermal expansion of the liquid on the saturation line and on the potassium isobar is found. The experimental data on density, compressibility, and ideal thermal expansion coefficients are used to estimate the position of the unit compressibility factor line and the inversion line of the Joule–Thomson effect for dense potassium in the temperature range K and pressures up to kbar. The considered data on the thermodynamic surface of liquid potassium require new experimental and theoretical work and expansion of the list of analyzed properties. [ABSTRACT FROM AUTHOR]

A series of novel circularly polarized luminescence (CPL) active liquid crystal materials ( R -BIN-OC and R -BIN-NC) were prepared by covalent-linking of R -binaphthol and cyanostilbene (CS) via either an ester or an amide. The effects of covalent bond structure with liquid crystal property, optical behavior, and chiroptical response were systematically evaluated. The results revealed that R -BIN-OC and R -BIN-NC can be self-assembled to form the columnar liquid crystal, and their phase transition temperatures were remarkably increased with the increase of the conjugation effect, accompanied by the expansion of the liquid crystal range. Importantly, they presented higher fluorescence performance with Φ F values of 26 % and 34 % in the solid-state, respectively. Moreover, the chiral of R -binaphthyl was effectively transferred to the CS fluorophore through covalent bond assembly. Meanwhile, the molecule displayed a strong CPL signal in the solid film, and the g lum values were gradually enlarged from −7.15 × 10−3 to −1.08 × 10−2 with the extension of the conjugation effect. This work illuminated the connection of chiral AIE liquid crystal molecules between conjugated structure and CPL property, providing a new strategy for constructing liquid crystal systems with efficient CPL properties. [Display omitted] • The CPL-active LC molecules ( R -BIN-OC and R -BIN-NC) based on BINOL-CS derivatives were prepared. • They demonstrated columnar phase LC and excellent AIE properties. • They showed a successful transfer of chirality from BINOL to the achiral CS. • The g lum value displayed ranged from −7.15 × 10−3 to −1.08 × 10−2 in solid film. [ABSTRACT FROM AUTHOR]

An innovative open natural circulation system is proposed in this work, which utilizes the difference of the heat flux loaded on different parts of the pipe to form a self-circulation flow of working fluid. Via CFD simulation established by embedding self-programmed code into commercial software, the transient performance of a three-dimensional natural circulation loop is studied. The results indicate that: applying uniform heat flux on the wall of the loop, the fluid flow state successively experiences three stages, i.e., liquid expansion, partial circulation, and phase change, and finally a vapor plunger blocks the pipe, leading to local heat transfer deterioration and temperature increase; applying non-uniform heat flux, the fluid can be driven to form self-circulation flow, which can not only cool the structure via convection, but also prevent bubbles from accumulating, stabilizing the maximum temperature of the system around the boiling point; further for the loop with a more complex configuration, the self-circulation can be also started but with different start modes. Therefore, the new natural circulation system can achieve effective and adaptive cooling according to the external thermal environment, avoid fluctuation and vapor block phenomenon caused by violent phase change, and reduce the driving equipment and control unit. This work provides a reference for the design of the natural circulation system applied in a non-uniform heating environment. Through transient numerical simulation of the start-up stage, the fluid flow, phase change, and heat transfer characteristics in the natural circulation loop are studied, and the start mode and mechanism are analyzed. [ABSTRACT FROM AUTHOR]