Fluid Environment Research Articles

Hydrodynamic and kinematic characteristics of high-speed inclined water-exit process in wave environment

Aiming at the process of underwater vehicle crossing the water-air interface based on the computational fluid dynamics(CFD) method, integrating the volume of fluid(VOF) and dynamic fluid body interaction(DFBI) models, a numerical simulation method for the trans-media process in a wave environment was studied. The motion simulation method of underwater vehicle under the action of complex fluid environment was established. The simulation of the water-exit process of the underwater vehicle in a wave environment has been realized. The accuracy verification of the wave-making and trans-media processes has been completed. The hydrodynamic and kinematic characteristics of the vehicle during the water-exit process have been obtained. The influences of the wave phase and velocity on the force and motion characteristics of the underwater vehicle were obtained, which provides technical support for designing the unmanned vehicles.

Research advances on the mechanisms of reservoir formation and hydrocarbon accumulation and the oil and gas development methods of deep and ultra-deep marine carbonates

Based on the new data of drilling, seismic, logging, test and experiments, the key scientific problems in reservoir formation, hydrocarbon accumulation and efficient oil and gas development methods of deep and ultra-deep marine carbonate strata in the central and western superimposed basin in China have been continuously studied. (1) The fault-controlled carbonate reservoir and the ancient dolomite reservoir are two important types of reservoirs in the deep and ultra-deep marine carbonates. According to the formation origin, the large-scale fault-controlled reservoir can be further divided into three types: fracture-cavity reservoir formed by tectonic rupture, fault and fluid-controlled reservoir, and shoal and mound reservoir modified by fault and fluid. The Sinian microbial dolomites are developed in the aragonite-dolomite sea. The predominant mound-shoal facies, early dolomitization and dissolution, acidic fluid environment, anhydrite capping and overpressure are the key factors for the formation and preservation of high-quality dolomite reservoirs. (2) The organic-rich shale of the marine carbonate strata in the superimposed basins of central and western China are mainly developed in the sedimentary environments of deep-water shelf of passive continental margin and carbonate ramp. The tectonic-thermal system is the important factor controlling the hydrocarbon phase in deep and ultra-deep reservoirs, and the reformed dynamic field controls oil and gas accumulation and distribution in deep and ultra-deep marine carbonates. (3) During the development of high-sulfur gas fields such as Puguang, sulfur precipitation blocks the wellbore. The application of sulfur solvent combined with coiled tubing has a significant effect on removing sulfur blockage. The integrated technology of dual-medium modeling and numerical simulation based on sedimentary simulation can accurately characterize the spatial distribution and changes of the water invasion front. Afterward, water control strategies for the entire life cycle of gas wells are proposed, including flow rate management, water drainage and plugging. (4) In the development of ultra-deep fault-controlled fractured-cavity reservoirs, well production declines rapidly due to the permeability reduction, which is a consequence of reservoir stress-sensitivity. The rapid phase change in condensate gas reservoir and pressure decline significantly affect the recovery of condensate oil. Innovative development methods such as gravity drive through water and natural gas injection, and natural gas drive through top injection and bottom production for ultra-deep fault-controlled condensate gas reservoirs are proposed. By adopting the hierarchical geological modeling and the fluid-solid-thermal coupled numerical simulation, the accuracy of producing performance prediction in oil and gas reservoirs has been effectively improved.

Motor domain of condensin and step formation in extruding loop of DNA.

During the asymmetric loop extrusion of DNA by a condensin complex, one domain of the complex stably anchors to the DNA molecule, and another domain reels in the DNA strand into a loop. The DNA strand in the loop is fully relaxed, or there is no tension in the loop. Just outside of the loop, there is a tension that resists the extrusion of DNA. To maintain the extrusion of the DNA loop, the condensin complex must have a domain capable of generating a force to overcome the tension outside of the loop. This study proposes that the groove-shaped HEAT repeat domain Ycg1 plays the role of a molecular motor. A DNA molecule may bind to the groove electrostatically, and the weak binding force facilitates the random thermal motion of DNA molecules. A mechanical model that random collisions between DNA and the nonparallel inner surfaces of the groove may generate a directional force which is required for the loop extrusion to sustain. The hinge domain binds to the DNA molecule and acts as an anchor during asymmetric DNA loop extrusion. When the effects of ATP hydrolysis and the viscous drag of the fluid environment are considered, the motor-anchor model for the condensin complex and the mechanical model might explain the asymmetric loop extrusion, the formation of steps, the step size distribution in the loop extrusion, the tension-dependent extrusion speed, the interaction between coexisting loops on the DNA strand, and untying the knots during extrusion. This model can also explain the observed formation of the Z-loop.

Regulatory autonomy in digital trade agreements

Abstract Digital trade agreements have become integral fora for regulating cross-border digital commercial transactions, including data flows. Deeper commitments in the area of digital trade have however raised serious concerns over the erosion of countries’ regulatory autonomy, prompting the inclusion of an array of safeguards within these treaties. This article undertakes a comprehensive examination of these safeguard mechanisms, which include carve-outs, transition periods, the right to regulate, and exception clauses. By shedding light on the nuances of these safeguard provisions, as well as their complex interplay with commitments made, the article provides a deeper understanding of the evolving dynamics of digital trade governance and its implications for national regulatory autonomy. Based on existing jurisprudence and legal doctrine, the article also tests the scope of the provided policy space, the trade-offs between flexibility and legal certainty, and examines how future-proof the bounds of regulatory autonomy are, considering the highly fluid technological environment.

Predicting multiphase flow behavior of methane in shallow unconfined aquifers using conditional deep convolutional generative adversarial network

Numerical modeling is an essential tool for geoscience applications involving multiphase flow behavior. Performing numerical simulation is, however, computationally intensive due to multi-scale, non-linear, and multi-physics nature of mechanisms controlling multiphase flow dynamics. Additionally, the computational challenges associated with traditional numerical simulations limit their applicability for repetitive simulations required in inverse modeling, uncertainty analysis, and optimization tasks. To overcome these limitations, surrogate modeling has recently emerged as a viable solution. A surrogate model, which functions as a regression model, is trained using numerical simulation data. It approximates the input–output relationships within a dynamic fluid environment. We design surrogate models, based on conditional deep convolutional generative adversarial network (cDC-GAN), to map the cross-domain between input and output pairs in a multiphase multicomponent system, focusing on methane (CH4) migration in shallow unconfined aquifers. The cDC-GAN technique is selected due to its ability to generate high-fidelity surrogate models that effectively capture complex spatial distributions and heterogeneities. This technique excels in handling high-dimensional data, learning the intricate relationships between inputs and outputs, and producing realistic representations of subsurface phenomena. The trained cDC-GANs consider capillary entry pressure heterogeneity as input because this geologic attribute places first-order control on CH4 migration in subsurface. The outputs include CH4 saturation, water saturation, residual saturation of CH4, CH4 mole fraction, and CH4 molality. For each output, a separate cDC-GAN model is trained. Once trained, cDC-GANs can at any given time determine CH4 distribution in a shallow unconfined aquifer, both qualitatively and quantitatively. The cDC-GAN approach can be considered as a valuable complement to numerical simulations for predicting multiphase flow behavior in other geoscience-, energy-, and environmental applications such as contaminant transport, hydrocarbon production, and geological carbon dioxide and hydrogen storage.

Numerical study of MHD flow over stretching cylinder with variable Prandtl number and viscous dissipation in ternary hybrid nanofluids with velocity and thermal slip conditions

Industrial applications in domains such as warm rolling, crystal development, thermal extrusion and optical fiber illustration are seeing a significant increase. These applications specifically focus on addressing the challenge of a cylinder in motion inside a fluid environment. Elevated temperatures may affect the viscosity and thermal conductivity of fluids. Understanding the relationship between temperature and the properties of fluids is crucial. In light of these presumptions, the primary goal of this study is to examine, under transverse magnetic field, shape factor, velocity, thermal slip conditions and viscous dissipation, how temperature-dependent fluid properties could enhance the heat transfer efficiency and performance evolution of ternary hybrid nanofluid. In order to study flow fluctuations, the impact of nanoparticle addition and improvements in heat transfer, a variable Prandtl number is also included. The use of similarity variables converts the controlling flow model from partial differential equations (PDEs) to ordinary differential equations (ODEs). Mathematica’s shooting strategy solves ODEs using the fourth-order Runge–Kutta (RK-IV) method. Numerical calculations were done after setting parameters to acquire the desired results. Analytical data are provided in tables and graphs for convenient usage. The results showed that the velocity profile increases as the values of [Formula: see text], Pr, M, Re and S grow, and decreases when the values of [Formula: see text] decrease. Re, Pr and S lower the temperature profile, whereas [Formula: see text], [Formula: see text] and Ec raise it. The skin friction profile steepens as [Formula: see text], S, Re and M increase relative to the stretched cylinder, and flattens as [Formula: see text] and [Formula: see text] decrease. The Nusselt number profile rises as [Formula: see text], Pr, S and Re decrease with [Formula: see text], Ec and [Formula: see text]. When the Prandtl number goes from 3.0 to 6.2 in a ternary hybrid nanofluid with brick-shaped nanoparticles, the Nusselt number goes up by around 55.7%.

Regulated anthocyanin release through novel pH-responsive peptide hydrogels in simulated digestive environment

The instability of anthocyanins significantly reduces their bioavailability as food nutrients. This proof-of-concept study aimed to develop efficient carriers for anthocyanins to overcome this challenge. Characterization of the hydrogels via SEM (scanning electron microscope) and rheological analysis revealed the formation of typical gel structures. MTT (methyl thiazolyl tetrazolium) and hemolysis assays confirmed that their high biocompatibility. Encapsulation efficiency analysis and fluorescence microscopy images demonstrated successful and efficient encapsulation of anthocyanins by pH-responsive hydrogels. Stability studies further validated the effect of peptide hydrogels in helping anthocyanin molecules withstand factors such as gastric acid, high temperatures, and heavy metals. Subsequently, responsive studies in simulated gastric (intestinal) fluid demonstrated that the pH-responsive peptide hydrogels could protect anthocyanin molecules from gastric acid while achieving rapid and complete release in intestinal fluid environments. These results indicate that these peptide hydrogels could stabilize anthocyanins and facilitate their controlled release, potentially leading to personalized delivery systems.

Experimental Study On Bubble Pairs And Induced Flow Fields Using Tomographic Particle Image Velocimetry

Gas-liquid two-phase flows, such as bubbly flows, are widely used across various engineering and military applications due to their distinctive fluid dynamics. This study utilizes advanced imaging techniques, including shadowgraphy and laser-induced fluorescence tomographic particle image velocimetry (LIF-TPIV), to provide a quantitative analysis of bubble motions and the resulting flow fields. We systematically investigate the effects of orifice distances (s) set at 10, 15, 20, and 25 mm to assess the impact of spacing on bubble behavior and interactions. Our findings indicate that at orifice distances of 20 mm or less, the proximity of bubbles facilitates interactions, promoting dynamic bubble behaviors. In contrast, at distances greater than 25 mm, interactions become markedly weaker, leading to increased separation between bubbles during their free oscillation stages. This weak interaction directly influences the characteristics of bubble-induced flow fields. As orifice spacing increases, there is a noticeable decrease in the velocity of the flow field between bubbles, particularly noticeable at spacings of 20 mm and above. At these larger spacings, a low-velocity zone develops between the bubbles at higher heights, which, according to Bernoulli's principle, corresponds to a high-pressure area. This high pressure contributes to a reduction in bubble volume with increasing orifice spacing. Furthermore, the intensity of wake vortices between two bubbles is observed to be highest at the smallest spacing of 10 mm, closely resembling the flow structure characteristic of a single rising bubble. For spacings of 15 and 20 mm, the induced flow fields of the bubbles continue to interact significantly. However, at a spacing of 25 mm, the flow fields appear to function independently, suggesting a threshold beyond which bubble interactions stop to significantly affect their surrounding fluid environments. These findings are helpful for comprehending the two-phase flow dynamics, particularly in multi-orifices bubbly flow.

Probiotic characteristics and whole genome sequence analysis of Lactiplantibacillus plantarum ZFM518 isolated from infant feces

AbstractEmerging research has shown that lactic acid bacteria in the intestines of newborns play a beneficial role in the growth, immune function, and metabolism of infants after birth. In this study, four strains of Lactobacillus were isolated from fecal samples of newborns, and a safe Lactiplantibacillus plantarum ZFM518 (ZFM518) strain was obtained after the screening, which showed excellent antibacterial activity and adhesion potential. The strain exhibited excellent ability to survive in acidic environments, simulated gastric juice, and simulated intestinal environments, respectively. ZFM518 had a bacteriostatic zone of 31.12 ± 0.33 mm against Staphylococcus aureus, a hydrophobic rate of 76.97% ± 3.35%, and a survival activity of 96.54% ± 0.14% under a simulated intestinal fluid environment. Moreover, ZFM518 can produce up to 161.11 ± 9.67 ng/mL of folate. A genome‐wide investigation of ZFM518 revealed that the majority of its genes were involved in the metabolism of amino acids, carbohydrates, adhesion, immunological defense, and antibacterial activity. In addition, only one antibiotic resistance gene of the antimicrobial peptide was annotated. These results indicate that ZFM518 is a new strain with a strong comprehensive ability and probiotic potential. This study can provide practical support for screening potential probiotics from infant feces and provide a theoretical basis for developing probiotic resources.

A novel method of reclaiming high-value carbon fiber from waste epoxy composite via molten salt thermal treatment

Epoxy resin limits the recycling of high-value carbon fibers from waste epoxy composites: its inferior thermal conductivity requires the excessive pulverization of the polymers, reducing fibers length; its robust cross-linked structure hinders its removal, leading to fiber contamination. Here, we proposed a novel method by using molten salts as an effective medium to enhance heat transfer and thermal reaction. The length and structural integrity of fibers were preserved by minimizing the extent of pulverization and reducing the erosive impact of resin degradation products, respectively. At 375 °C, the resin removal ratio and fiber strength retention both exceeded 99%, with a temperature reduction of at least 100 °C. Molten salts exerted differential inert and active effects on fibers and resin. Fibers could retain 97% of strength retention within salts at 400 °C for 2 h. Conversely, molten salts significantly facilitated the disruption of the resin matrix’s cross-linked structure by catalyzing the cleavage of C-N bonds. The degradation products exhibited a lightweight tendency and could be easily separated from the fiber surface in the fluid environment provided by molten salts, thus protecting the fiber surface against oxidative erosion caused by phenols.

Numerical simulation of cone penetration test by using CFD–DEM coupled analysis

Precise stratigraphic characterization and assessment of soil parameters are essential for agricultural and geotechnical engineering. The cone penetration test (CPT) has become one of the most extensively used techniques for soil site assessment, because of its reproducibility, robustness, accuracy, and simplicity. The existing DEM (discrete element method) simulations on CPT are only applicable to dry soil, which cannot consider fluid phase (i.e., pore water) and its interaction with the soil particles. The combined DEM and CFD (computational fluid dynamics) approach is developed to model CPT testing on saturated soils in this study. Several sets of CPT simulations at various penetration rates have been performed by using CFD–DEM coupled analysis. The variation of penetration velocity leads to different magnitudes of fluid force, and the variation in fluid force, in turn, affects the CPT measurement of soil’s characteristics. Furthermore, the study extends beyond the properties of the soil itself to explore the complex interplay among soil particles, the surrounding fluid environment, and the penetrometer. The cumulative interactions among these elements highlight the intricate nature of CPT and underline the importance of comprehensive computational models in enhancing our understanding of these dynamics.

Accelerated degradation testing impacts the degradation processes in 3D printed amorphous PLLA.

Additive manufacturing and electrospinning are widely used to create degradable biomedical components. This work presents important new data showing that the temperature used in accelerated tests has a significant impact on the degradation process in amorphous 3D printed poly-l-lactic acid (PLLA) fibres. Samples (c. 100 m diameter) were degraded in a fluid environment at C, C and C over a period of 6months. Our findings suggest that across all three fluid temperatures, the fibres underwent bulk homogeneous degradation. A three-stage degradation process was identified by measuring changes in fluid pH, PLLA fibre mass, molecular weight and polydispersity index. At C, the fibres remained amorphous but, at elevated temperatures, the PLLA crystallised. A short-term hydration study revealed a reduction in glass transition (Tg), allowing the fibres to crystallise, even at temperatures below the dry Tg. The findings suggest that degradation testing of amorphous PLLA fibres at elevated temperatures changes the degradation pathway which, in turn, affects the sample crystallinity and microstructure. The implication is that, although higher temperatures might be suitable for testing bulk material, predictive testing of the degradation of amorphous PLLA fibres (such as those produced via 3D printing or electrospinning) should be conducted at C.

Exploring Wave–Vegetation Interaction at Stem Scale: Analysis of the Coupled Flow–Structure Interactions Using the SPH-Based DualSPHysics Code and the FEA Module of Chrono

Aquatic vegetation in the littoral zone plays a crucial role in attenuating wave energy and protecting coastal communities from hazardous events. This study contributes to the development of numerical models aimed at designing nature-based coastal defense systems. Specifically, a novel numerical application for simulating wave–vegetation interactions at the stem scale is presented. The numerical model employed, DualSPHysics, couples the meshfree Smoothed Particle Hydrodynamics (SPH) fluid solver with a structural solver to accurately capture the two-way interactions between waves and flexible vegetation. The proposed numerical model is validated against experimental data involving a submerged rubber cylinder representing an individual vegetation stem, subjected to regular waves. The results demonstrate excellent agreement in hydrodynamics, force transfer, and the swaying motion of the flexible cylinder. Importantly, the approach explicitly captures energy transfer between the fluid environment and the individual stem. The numerical results indicate persistent turbulent flow along the vegetation stem, even when its swaying speed matches that of the surrounding environment. This reveals the presence of vortex shedding and energy dissipation, which challenges the concept of passive swaying in flexible aquatic vegetation.

Nanofluidic Membrane-Assisted Organic Electrochemical Transistors for Bioinspired Gustatory Sensation Based on Selective Cation Transport.

Natural organisms have evolved precise sensing systems relying on unique ion channels, which can efficiently perceive various physical/chemical stimuli based on ionic signal transmission in biological fluid environments. However, it is still a huge challenge to achieve extensive applications of the artificial counterparts as an efficient wet sensing platform due to the fluidity of the working medium. Herein, nanofluidic membranes with selective cation transport properties and solid-state organic electrochemical transistors (OECTs) with amplified signals are integrated together to mimic human gustatory sensation, achieving ionic gustatory reagent recognition and a portable configuration. Cu-HHTP nanofluidic membranes with selective cation transport through their uniform micropores are constructed first, followed by assembly with OECTs to form the designed nanofluidic membrane-assisted OECTs (nanofluidic OECTs). As a result, they can distinguish typically ionic gustatory reagents, and even ionic liquids (ILs), demonstrating enhanced gustatory perception performance under a wide concentration range (10-7-10-1m) compared with those of conventional OECTs. The linear correlations between the response and the reagent concentration further indicate the promising potential for practical application as a next-generation sensing platform. It is suggested that nanofluidic membranes mediated intramembrane cation transport based on the steric hindrance effect, resulting in distinguishable and improved response to multiple ions.

FimH-mannose noncovalent bonds survive minutes to hours under force

The adhesin FimH is expressed by commensal Escherichia coli and is implicated in urinary tract infections, where it mediates adhesion to mannosylated glycoproteins on urinary and intestinal epithelial cells in the presence of a high-shear fluid environment. The FimH-mannose bond exhibits catch behavior in which bond lifetime increases with force, because tensile force induces a transition in FimH from a compact native to an elongated activated conformation with a higher affinity to mannose. However, the lifetime of the activated state of FimH has not been measured under force. Here we apply multiplexed magnetic tweezers to apply a preload force to activate FimH bonds with yeast mannan, then we measure the lifetime of these activated bonds under a wide range of forces above and below the preload force. A higher fraction of FimH-mannan bonds were activated above than below a critical preload force, confirming the FimH catch bond behavior. Once activated, FimH detached from mannose with multi-state kinetics, suggesting the existence of two bound states with a 20-fold difference in dissociation rates. The average lifetime of activated FimH-mannose bonds was 1000 to 10,000 s at forces of 30–70 pN. Structural explanations of the two bound states and the high force resistance provide insights into structural mechanisms for long-lived, force-resistant biomolecular interactions.

Hybrid isogeometric-based analysis and experimental investigation on the dynamic response characteristics of a clamped circular plate partially in contact with fluid

The aim of this study was to analyze the effect of fluid presence on the dynamic response characteristics of the thin circular plate and the distortions associated with the wet mode shapes. To this end, series of numerical calculations and experimental measurements were performed to investigate the free vibration characteristics of clamped circular plate under in-vacuo conditions and when it is partially in contact with fluid. In the experimental studies, the clamped boundary conditions are imposed on the circular end plate of the horizontal rigid cylindrical tank by closely-spaced bolts, and measurements were performed based on roving hammer impact technique. The proposed numerical approach was divided into two parts based on linear hydroelasticity theory. In the first stage, the thin circular plate is considered to be under in-vacuo conditions, and the mathematical model for this problem is developed based on the isogeometric finite element method (IGAFEM). The fluid environment is introduced in the second stage of the study in which the generalized in-vacuo modal displacements constitute the boundary conditions of the potential flow problem. The influence of fluid medium is incorporated in the system of equations in the form of fluid added mass, and the corresponding fluid forces are calculated by the isogeometric boundary element method (IGABEM). It is observed that the fluid presence has significant effects on the dynamic response characteristics of the test structure, and the specifically, the distortions of wet mode shapes were noticeable due to presence of free surface of the water. Overall, it is found that the natural frequencies and corresponding mode shapes obtained by conducted experiments and adapted numerical framework are in favorable agreement.

Growth mechanism of high‐voltage electric pulse rock breaking 3D plasma channel in drilling fluid environment

AbstractHigh‐voltage electric pulse rock breaking has excellent potential for exploiting deep geothermal resources. Numerous researchers have conducted experimental studies on this topic, particularly in rock mechanics, where the breakdown occurs. However, there has been limited scholarly research on drilling fluid. Therefore, the study focuses on the drilling fluid suitable for electric pulse drilling, considering the characteristics of electric pulse rock breaking, which differ from traditional rock breaking. The study focused on the impact of various drilling fluid parameters on the effectiveness of electric impulse rock breaking using red sandstone as the experimental material. This was investigated using the finite element method, and indoor electric rock‐breaking tests were conducted in a drilling fluid environment. The results indicate that the plasma channel mainly grows in the permeable layer of the drilling fluid, resulting in shallow rock breaking depth in the drilling fluid environment. The pore permeated by drilling fluid guides the growth of the plasma channel. The higher the conductivity of the drilling fluid, the closer the ion channel of rock breaking by electric pulse is to the rock surface. This results in a smaller crushing volume and shallower damage depth, which is more detrimental to rock breaking by an electric pulse. The viscosity of drilling fluid can impede the breakdown to some extent. In this paper, the influence of drilling fluid parameters on electro‐pulse rock‐breaking technology is preliminarily studied, which has significant reference value for the selection of actual drilling fluid.

Biomechanical evaluation of double-stranded knot configurations in high-strength sutures and tapes.

Recently, a new dynamic high-strength suture (DC) was introduced, also available in tape form (DT), featuring a salt-infused silicone core attracting water in a fluid environment to preserve tissue approximation. The aims of this study were to (1) assess the influence of securing throw number on knot security of two double-stranded knot configurations (Cow-hitch and Nice-knot) tied with either dynamic (DC and DT) or conventional (FW and ST) high-strength sutures and tapes, and (2) compare the ultimate force and knot slippage of the novel dynamic versus conventional sutures and tapes when used with their minimal number of needed securing throws. Seven specimens of each FW, ST, DC and DT were considered for tying with Cow-hitch or Nice-knots. The base of these Cow-hitch and Nice-knots was secured with surgeons` knots using 1-3 alternating throws. Tensile tests were conducted under physiologic conditions to evaluate knot slippage, ultimate force at rupture, and minimum number of throws ensuring 100% knot security. RESULTS: For both Cow-hitch and Nice-knots, 100% security was achieved with 2 securing throws for DC, DT, ST, and with 3 securing throws for FW. With these minimum numbers of securing throws, ultimate force was significantly higher for Nice-knots versus Cow-hitch tied with DT (p = 0.001) and slippage was significantly less with Nice-knots versus Cow-hitch tied with DC (p = 0.019). The minimum number of securing throws required to achieve 100% security was 2 with DC, DT and ST for both Cow-hitch and Nice-knots configurations, in contrast to FW where 3 securing throws were needed. With these minimum numbers of securing throws, Nice-knots were associated with significantly higher ultimate forces when using DT and lower slippage with DC versus Cow-hitch knots.

On the Photothermal Response of DNA–Au Core/Shell Nanotoroids as Potential Agents for Photothermal Therapies

Plasmonic nanoparticles play a pivotal role in various research areas due to their exceptional optical and thermo‐optical properties, like high spectral tunability and efficient light‐to‐heat conversion. Gold, with its biocompatibility, low cytotoxicity, and tunable resonances , makes gold nanoparticles ideal for photothermal therapies. Geometries, including spheres, core–shells, rods, disks, stars, nanocages, and nanotoroids, are extensively studied, with the gold nanodoughnut emerging as one of the most promising ones due to its ability to produce high temperatures and rotational stability. Nevertheless, the fabrication of metallic toroidal shapes remains a challenge. Recent advances in DNA‐based nanotechnology, especially DNA‐origami techniques, provide feasible route for the fabrication of this geometry through metallization reactions or attachment of metal nanoparticles. However, particles manufactured using this method possess a DNA core that influences their thermoplasmonic performance. In this work, a theoretical investigation is conducted on the thermoplasmonic response of DNA‐origami‐based core/shell toroids (CSTs) for photothermal applications. Key parameters that optimize the CST thermoplasmonic response are identified, and compared with their solid counterparts and discrete metallic coatings. Additionally, the CSTs tolerance to random rotations is assessed, providing insights into their behavior in fluidic environments and implications for its practical consideration.

Research on Erosion Mechanism and Protection Technology of Sand Bearing Fluid Pipeline

The purpose of this study is to explore the influencing factors of sand bearing fluid on pipeline erosion and evaluate the effects of different protection technologies. Through the construction of erosion testing equipment, the influence of sand particle size, concentration and flow rate on the erosion rate was systematically studied. The results show that the increase of sand particle size and concentration and the increase of flow rate will significantly increase the erosion rate. In addition, coating protection technology and alloying technology have been proved to be effective in reducing the erosion rate, and coating protection technology shows better protection effect. It provides theoretical basis and data support for pipeline design and protection in sand bearing fluid environment.