Fluid Conditions Research Articles

Enrichment of electrotrophic microorganisms from contrasting shallow-sea hydrothermal environments in bioelectrochemical reactors

IntroductionHydrothermal vents are inhabited by electrotrophic microorganisms, which are capable of oxidizing extracellular compounds, such as metals, to power their metabolisms. However, their diversity is poorly known, especially in shallow-sea hydrothermal vents where it has not been extensively studied. Bioelectrochemical reactors can be used to investigate such electrotrophic diversity by providing an electrode as an electron donor.MethodsHere, a total of 60 different reactors were set up and inoculated with either a microbial community coming from the shallow, acidic (ca. pH 5.5) and hot (ca. 120°C) hydrothermal system of Panarea, Aeolian islands, Italy, or the shallow, alkaline (pH 11) and mild (40°C) hydrothermal system of Prony Bay, New Caledonia.ResultsWith the alkaline sample, no electrical current increase was seen in any of the 15 reactors operated for 6 days under Prony hydrothermal conditions (pH 10, 30–75°C). By contrast, a 6-fold increase on average was observed in reactors operated under the Panarea hydrothermal fluid conditions (pH 4.5–7, 75°C). A Multi-Factor Analysis revealed that the overall bioelectrochemical performances of these reactors set them apart from all the other Panarea and Prony conditions, not only due to their higher current production but also archaeal abundances (measured through qPCR). Most reactors produced organic acids (up to 2.9 mM in 6 days). Still, coulombic efficiencies indicated that this might have been due to the (electro) fermentation of traces of yeast extract in the medium rather than CO2 fixation. Finally, microbial communities were described by 16S metabarcoding and ordination methods, and potential electrotrophic taxa were identified. In Panarea reactors, higher growth was correlated with a few bacterial genera, mainly Bacillus and Pseudoalteromonas, including, for the former, at higher temperatures (55°C and 75°C). In reactors reproducing the Prony Bay hydrothermal conditions, known facultative methylotrophs, such as Sphingomonas and Methylobacterium, were dominant and appeared to consume formate (provided as carbon source) but no electrons from the cathode.ConclusionThese results provide new insights into the distribution and diversity of electrotrophs in shallow-sea hydrothermal vents and allow the identification of potential novel biocatalysts for Microbial Electrosynthesis whereby electricity and carbon dioxide are converted into value-added products.

Catalytic transesterification of rapeseed oil under supercritical fluid conditions and physical properties of the reaction product

This research examines the transesterification reaction of rapeseed oil with ethanol in the presence of heterogeneous catalysts - Al2O3 and CaO/Al2O3 with 2% mass impregnation of CaO. The experiments were carried out at a molar ratio of ethanol: rapeseed oil of 18:1 (volume ratio ≈ 1:1) at temperatures of 608, 623 K, and a pressure of 20 MPa for up to 30 minutes in a flow-type unit. The state’s selected pressure and temperature parameters correspond to the supercritical fluid conditions. The results are presented for kinematic viscosity (T=313 K, P=0.1 MPa), density (T=288÷323 K, P=0.1 MPa), refractive index (T=298 K, P=0.1 MPa) of the transesterification reaction product. A quantitative assessment of the target product was carried out using chromatographic analysis. We have established the influence of temperature and duration of the reaction process on its efficiency. We present the strength characteristics of the catalysts used before and after the experiments. During attrition, the initial Al2O3 catalyst lost weight by 0.4 ± 0.1%. The mechanical crushing strength along the generatrix was 7.1 ± 0.3 N/mm. The strength of catalysts after carrying out the transesterification reaction under supercritical fluid conditions decreases, on average, by 24-28%. The use of heterogeneous catalysts Al2O3 and CaO/Al2O3 with 2%wt. impregnation of CaO showed an increase in the fatty acid ethyl esters concentration in the transesterification reaction product compared to the reaction carried out without the use of catalysts.

Erosion-Corrosion: An Up-To-Date Review of Origin, Impacts, Affecting Factors, Occurrence Areas, Experimental Measuring Devices, and Research Advances

Abstract: An up-to-date review of erosion-corrosion from various literary sources, covering its origin, impacts, affecting factors, occurrence areas, experimental measuring devices, and research advances, is reported. From the review, erosion-corrosion is a mechanically caused action by impinging fluid, usually liquid, slurry abrasion, suspended particles in fast-flowing fluids, bubbles, droplets, cavitations, etc., under complex synergistic effects of the natural electrochemical corrosion. It is affected by many factors that still need to be fully understood, so it is very challenging to accurately find its rates for controlling it. It is a very costly problem that is common in power plants, water, oil, gas, metallurgy, mining, and other industrial sectors that utilize mechanical equipment as well as structural components in hydraulic environments. Its effects are predominant in petroleum pipelines and heat exchange industries, as well as marine equipment or structures. Its rates, time scale, and capacity to degenerate material components to failure are much more alarming than most other corrosion types. This corrosion type is highly detestable, so much attention has been drawn to it, as attested by many research outputs on it to date, with a pressing need for ways, including emerging technologies, of minimizing its impacts. Forty-six of the research outputs have been recapitulated and presented, and they focus on developing and/or testing alternative material components, coatings, measuring devices, and application of artificial intelligence, for better erosion-corrosion resistances or rate measurements and control under various fluid conditions. The paper provides integrated, up-to-date information on erosion-corrosion for easy accessibility for the needful basic knowledge for research progress towards reducing its impacts.

Biocompatible Heterogeneous Packaging and Laser-Assisted Fluid Interface Control for In Situ Sensor in Organ-on-a-Chip.

The development of bionic organ-on-a-chip technology relies heavily on advancements in in situ sensors and biochip packaging. By integrating precise biological and fluid condition sensing with microfluidics and electronic components, long-term dynamic closed-loop culture systems can be achieved. This study aims to develop biocompatible heterogeneous packaging and laser surface modification techniques to enable the encapsulation of electronic components while minimizing their impact on fluid dynamics. Using a kidney-on-a-chip as a case study, a non-toxic packaging process and fluid interface control methods have been successfully developed. Experimentally, miniature pressure sensors and control circuit boards were encapsulated using parylene-C, a biocompatible material, to isolate biochemical fluids from electronic components. Ultraviolet laser processing was employed to fabricate structures on parylene-C. The results demonstrate that through precise control of processing parameters, the wettability of the material can be tuned freely within a contact angle range of 60° to 110°. Morphological observations and MTT assays confirmed that the material and the processing methods do not induce cytotoxicity. This technology will facilitate the packaging of various miniature electronic components and biochips in the future. Furthermore, laser processing enables rapid and precise control of interface conditions across different regions within the chip, demonstrating a high potential for customized mass production of biochips. The proposed innovations provide a solution for in situ sensing in organ-on-a-chip systems and advanced biochip packaging. We believe that the development of this technology is a critical step toward realizing the concept of "organ twin".

Identification of Hydroandradite in CM Carbonaceous Chondrites: A Product of Calc-Silicate Alteration on C-Complex Asteroids

A hydrous Ca-Fe-rich silicate identified as hydroandradite was observed in the ‘Mighei19 type’ carbonaceous (CM) chondrite falls, Shidian and Kolang. This is the first report of hydroandradite occurring within meteorites. Hydroandradite forms through aqueous calc-silicate alteration under specific fluid conditions. Its presence within Shidian and Kolang has implications for interpreting alteration processes within the C-complex asteroid parent bodies of the CM chondrites. To better understand its occurrence, the meteoritic hydroandradite was studied with scanning electron microscopy, electron probe microanalysis, transmission electron microscopy, and Raman spectroscopy. It occurs in four petrographic contexts: layered, perovskite-associated, sulphide-associated, and spheroidal. Kolang has all four morphologies, while only the sulphide-associated occurs in Shidian. In Kolang, hydroandradite was likely produced by replacement of kamacite, Ti-bearing clinopyroxene in calcium- and aluminium-rich inclusions, and secondary magnetite in three distinct alteration events. The formation temperature of meteoritic hydroandradite was estimated to be 100–245°C, based on the mineralogy of the lithologies within which it occurs as well as on its degree of hydration relative to synthetic and terrestrial hydroandradites. Because Kolang and Shidian are the only reported meteorites with hydroandradite to date, they may be from the same parent body.

Uniform stabilization in Besov spaces with arbitrary decay rates of the magnetohydrodynamic system by finite-dimensional interior localized static feedback controllers

We consider the d-dimensional MagnetoHydroDynamics (MHD) system defined on a sufficiently smooth bounded domain, d=2,3 with homogeneous boundary conditions, and subject to external sources assumed to cause instability. The initial conditions for both fluid and magnetic equations are taken of low regularity. We then seek to uniformly stabilize such MHD system in the vicinity of an unstable equilibrium pair, in the critical setting of correspondingly low regularity spaces, by means of explicitly constructed, static, feedback controls, which are localized on an arbitrarily small interior subdomain. In additional, they will be minimal in number. The resulting space of well-posedness and stabilization is a suitable product space B~q,p2-2/p(Ω)×B~q,p2-2/p(Ω),1<p<2q2q-1,q>d, d,$$\\end{document}]]> of tight Besov spaces for the fluid velocity component and the magnetic field component (each “close” to L3(Ω) for d=3). Showing maximal Lp-regularity up to T=∞ for the feedback stabilized linear system is critical for the analysis of well-posedness and stabilization of the feedback nonlinear problem.

Building a Digital Twin for a Ground Heat Exchanger

AbstractThis research investigates the development of a digital twin (DT) for ground heat exchangers (GHEs) and its potential to enhance the efficiency and sustainability of shallow geothermal energy systems. It introduces an innovative approach for building a GHE‐DT that connects the physical and digital systems to monitor key parameters, predict issues, and optimize energy efficiency. The process involves several phases including implicit knowledge codification, data‐driven analysis, model construction, and system design. The study emphasizes real‐time monitoring of the effective parameters: ground temperature and fluid conditions (flow rate, temperature, and pressure). The GHE‐DT's digital system mainly comprises three sections, namely, data storage, mathematical modeling, and data‐driven modeling. The role of the presented mathematical model is to simulate the GHE's behavior and assess its performance characteristics, such as the heat exchanger's effectiveness and efficiency. Additionally, the data‐driven model used in the proposed DT utilizes formal concept analysis and relation concept analysis to identify connections and associations among parameters for a better understanding of the GHE functioning. The GHE‐DT provides useful services including trend analysis, problem prediction, and correlation analysis. These services provide engineers and operators with the opportunity to increase dependability, save maintenance costs, and optimize GHE performance.

Тhermal history and fluid regime during the formation of Eldjurta massif of biotite granites (Greater Caucasus): reconstructions based on isotope (δ&lt;sup&gt;18&lt;/sup&gt;О, δD) and geochemical data

Based on the geochemical and isotopic (δ18О, δD) data the thermal and fluid conditions during the formation of the Eldjurta granite massif were reconstructed. Analysis of rocks collected from the core of the Tyrnyauz Superdeep Well (TSW) within the depth range of 1427–3923 m revealed their homogeneous isotopic parameters: the δ18О values of bulk samples, quartz, feldspars, and biotite in 12 samples of biotite granites are 8.50 ± 0.33, 9.55 ± 0.22, 8.40 ± 0.33 and 5.45 ± 0.40‰, respectively. The δD values in the biotite vary from −103.3 to −95.6‰. The closure temperatures of the oxygen isotope system of quartz are 440–980°C. The rock cooling history was reconstructed using a new approach based on the analysis of single quartz grains. This approach can be used for detailed reconstructions of thermal history during formation of intrusive bodies. The definite samples were used to demonstrate that Dodson’s equation is valid for description of the δ18О values of quartz in a granite system. The data obtained suggest that the studied part of the massif was formed in at least two almost simultaneous stages. The lower part of the massif was crystallized first, and the second injection of granite melt arrived immediately after the first portion has been crystallized, but had no yet had time to cool significantly. The Тс values in the lower part of the massif indicate the reopening of the oxygen isotope system of quartz, with subsequent long-term isotope re-equilibration between minerals. This leads to decrease of the observed Тс values and the calculated cooling rates, which is related to increasing volume of the intrusive body and cooling within already heated rocks. Estimates of the isotopic parameters of the water component indicate the absence of exotic water fluid (meteoric or buried waters) during cooling of the massif. The variations of the δ18О values in the minerals of the Eldjurta biotite granites can be described only in terms of a simple retrograde exchange at the cooling stage

Biodegradation and Thermomechanical Behavior of 3D-Printed PLA Scaffolds Under Static and Stirring Biomimetic Conditions.

3D-printed biomedical polylactic acid (PLA) scaffolds were developed, and their biodegradation, as well as their thermomechanical behavior, were studied in a relevant in vitro environment. The scaffold's biodegradability profile has been monitored after immersion in a cell culture medium that contains components of blood and body fluids. Two types of biodegradation experiments were performed-a standard static one and an adapted stirring one, mimicking the body fluids' flow, respectively-to achieve a comparative investigation. The biodegradation experiment's duration was one month. The measurements were performed between days 1 and 28. The scaffold microstructure was analyzed with scanning electron microscopy (SEM). The weight loss of the scaffolds has been monitored. Differential scanning calorimetry (DSC) has been used to evaluate the glass transition temperature (Tg) of the scaffolds and to draw useful conclusions about their thermal behavior. Finally, dynamic mechanical analysis (DMA) was applied to investigate the viscoelastic behavior of the samples. The SEM analysis demonstrated that the samples in a static experiment are more damaged, while those in the stirring experiment are more brittle. The maximum Tg value of the material measured by DSC is around 65 °C. This value is reached after 5 days of immersion in static conditions and after 14 days of immersion after stirring, indicating that some processes take place faster in the static experiment. The variation of the Tg vs. immersion time, as derived from DSC vs. DMA measurements, gives similar results for both static and fluid absorption conditions, demonstrating the reproducibility of the results.

Predictive Characterization of Fracture and Absorption Tests in Halite Formations: an integrated approach of numerical modeling and field data

This study introduces a predictive model based on field data from oil wells in the pre-salt region, focusing on the analysis of fractures in saline rocks and the simulation of leak-off tests through integration with the finite element method. The analysis utilized a variety of techniques, including the construction of a correlation matrix, statistical testing, linear adjustment methods, and numerical modeling. Utilizing specific field data from halite formations, the study identified overburden stress and sediment depth as the most critical variables for minimum stress. Three linear adjustment methods—least squares, genetic algorithms, and Bayesian methods—were employed. All methods demonstrated a strong correlation among the variables, with Bayesian methods exhibiting the lowest percentage error relative to experimental data. Residual analysis showed that the regression models provided accurate predictions, with most points closely matching the actual values. Numerical modeling further allowed for the assessment of rock behavior under different fluid conditions, indicating that the compositional fluid provides a more realistic simulation and adheres more closely to theoretical expectations and field data. The results affirm the efficacy of the proposed models, particularly highlighting the use of Bayesian methods and mathematical modeling integrated with the finite element method, in predicting the dynamics of fractures and fluid absorption in saline formations. This model significantly enhances the characterization of fractures and absorption pressures in oil wells, improving its utility in predicting behaviors in formations associated with pre-salt fields.

An Adaptive Ensemble Approach Using Online Global and Local Models for Pump Pressure Prediction in Well Cementing Operations

Summary In cementing operations, conventional methods for predicting wellhead pump pressure, which rely on empirical and numerical models, often fall short regarding real-time accuracy and adaptability to different geological blocks and cementing techniques. These shortcomings hinder precise control of the wellhead pressure range, impacting operational safety, efficiency, and on-site personnel guidance. Furthermore, traditional offline machine-learning models cannot handle concept drift due to changing downhole fluid conditions during cementing. This paper frames wellhead pump pressure prediction as an online regression forecasting problem that utilizes the strengths of incremental and online ensemble learning with the Hoeffding tree regressor to overcome these challenges. First, data features are partitioned into subsets to create base learners, and then global and local models are deployed to address concept drift. The dynamic integration of these models significantly improves adaptability and performance. Experimental results confirm the superiority of our method over existing approaches. Compared with the suboptimal online models, mean squared error (MSE) is reduced for pump pressure prediction in five cementing data sets by 74.65%, 75.09%, 59.27%, 65.21%, and 70.01%, respectively. Additionally, MSE is reduced by 52.46%, 51.18%, 42.93%, 57.12%, 56.23%, 64.83%, and 79.51%, respectively, in seven open data sets, which showcases the broad applicability of our method to other regression tasks.

OPTIMIZATION OF HYDRODYNAMIC PARAMETERS OF DRILLING FLUIDS FOR IMPROVED CUTTINGS TRANSPORT IN HORIZONTAL WELLS

In horizontal portions of small-bore well holes, improper cuttings transportation results in high torque and raises the possibility of the drill being stuck, shortening its service life and endangering safe operation. A transport approach utilizing pulsed drilling fluid based on a shunt relay mechanism is suggested since the traditional cuttings transport method is ineffective at removing the cuttings bed. The transport of cuttings in horizontal small-bore wells is modeled numerically using three layers. The cuttings transport is examined in terms of the cuttings concentration, cuttings velocity, and cuttings bed movement distance using both numerical models and tests. The best pulse parameters are identified by adjusting the pulsed drilling fluid velocity cycle, amplitude, and duty cycle at the annulus inlet and assessing the impact on cuttings transport. The findings demonstrate that pulsed drilling fluid can be used to improve wellbore cleaning, lower cuttings concentration, and increase the cuttings bed's transport distance and moving cutting velocity. A steady flow rate of drilling fluid is used in the traditional cuttings transportation method. Simulations using the three-layer numerical model show that the cuttings bed's movement distance is decreased to the point where the wellbore's cleaning effect falls short of its intended level when the cuttings bed's height in the annulus surpasses a critical value. A technique using pulsed drilling fluid has been suggested to enhance transportation. By altering the drilling fluid's flow rate, this continuously affects the cuttings. Because pulsed jet drilling technology can effectively boost drilling speed, downhole drilling instruments that use pulsed jets are outfitted with spiral pressure intensifiers and variable-frequency pulse jet generators. According to field tests, using pulsed drilling fluid improves cuttings transport efficiency and lessens the impact of chipping. The majority of cuttings transport research to date has been on how cuttings behave under typical drilling fluid flow conditions. Relatively few studies exist about the destruction of the cuttings bed or the transportation of cuttings under conditions of pulsed drilling fluid. This research establishes a three-layer numerical model under pulsed fluid circumstances based on a shunt relay mechanism. This research describes the transport of cuttings in horizontal well sections under pulsed drilling fluid circumstances in terms of factors, such as the cuttings concentration, the cuttings bed's distance traveled, and the moving cuttings velocity, using both numerical models and tests. Furthermore, the ideal pulse parameters are found, which serves as a crucial guide for designing cuttings transport using pulsed drilling fluid tools. A three-layer numerical simulation model of cuttings transport utilizing a pulsed drilling fluid in the horizontal section of a narrow-bore hole is constructed in the second section of the article, which is based on actual onsite working conditions. The experimental apparatus and procedures are presented in the third section, and the experimental data are used to study the behavior of cuttings transport by the pulse drilling fluid. The cuttings transport behavior for various values of th is examined in the fourth section using finite element software. Keywords: CFD model, cuttings bed, pulsed drilling fluid, and horizontal well drilling

3D printing of biomimetic hierarchical surface textures using L-PBF for improving tribological performance of Ti6Al4V alloy

Energy and material losses due to friction and wear during the use of materials bring about very serious costs in every sector. In order to minimize friction and wear losses of materials, different surface engineering applications are used, especially surface coatings, thermal, mechanical and thermochemical processes. On the other hand, it has been shown in recent years that the tribological properties of materials can be controlled by creating different types of biomimetic hierarchical patterns on the surface of materials. Therefore, this study investigates both the individual and the synergetic effects of both biomimetic surface textures and thermal oxidation process on the tribological performance of Ti6Al4 V alloy. For this purpose, hierarchical models were produced using the laser powder bed fusion (L-PBF) technique, which is one of the additive manufacturing methods. Snake skin, shark skin and tree frog models were used as biomimetic hierarchical models. Additionally, flat and random snake skin models were used to examine the effect of texture orientation. Moreover, thermal oxidation was carried out at 700 ⁰C for 2 h and 4 h and the wear tests were carried out using a reciprocation-type tribo-tester under dry and simulated body fluid (SBF) conditions. As the oxidation time increased, the hardness and surface roughness of the material increased. A significant improvement in the wear rate of biomimetic models was observed compared to the non-textured sample. Lower tribological performance was observed in the tree frog model (hexagonal geometry) compared to other biomimetic models due to the presence of sharp corners. In particular, the snakeskin model provided the best wear rate because it trapped wear residue and provided additional hydrodynamic pressure. The highest tribological performances for all samples were observed in the samples oxidized at 700 ⁰C for 4h.

Robust Control Strategy of Acoustic Micro Robots Based on Fuzzy System.

This study presents a robust control strategy for acoustic micro robots utilizing a novel interval type-three fuzzy system. Micro robots driven by acoustic forces face significant challenges in fluid environments due to complex nonlinearities, uncertainties, and disturbances. To address these issues, we propose a control framework that combines fuzzy logic and sliding mode control to enhance the stability and trajectory tracking performance of micro robots under varying fluid conditions. The interval type-3 fuzzy logic system provides increased robustness by better handling external disturbances and uncertainties compared to the robustness of the traditional methods. The experimental results from one-dimensional, two-dimensional, and three-dimensional fluid cavities demonstrate that the proposed control method significantly improves tracking accuracy, reducing the errors in complex environments. This control framework offers promising potential for the precise manipulation of micro robots in biomedical applications and other microfluidic systems. The minimum trajectory tracking control mean square error is 12.82 μm.

Abstract 4138348: Mechanical stress-mediated nuclear envelope damage promotes Aortic Valve Calcification through the ZBP1-RIPK3-NF-κB signaling axis

Methods and Results: We describe a comprehensive characterization of the AVICs nucleus landscape as determined by transmission electron microscopy (TEM) of samples obtained from CAVD patients. Turbulence led to nuclear envelope integrity lose in AVICs cultured in shear stress experiments, with three different fluid conditions [static (ST), laminar stress (LS), and oscillatory stress (OS)], indicated by Western blot and immunofluorescence (IF). Silencing lamin A/C (LMNA) through small interfering RNA (siRNA), accelerated nuclear envelope damage , as indicated by Western blot, qPCR, and immunofluorescence (IF). The formation of Z-DNA and its co-localization with Z-DNA binding protein (ZBP1) was observed due to the nuclear envelope damage by IF. Western blot, qPCR, IHC and IF confirmed Z-DNA-induced inflammation in AVICs through the ZBP1-RIPK3-NF-κB signaling pathway. ZBP1 and RIPK3 knockdown with siRNA markedly reduced the protein level of osteogenic markers alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2), and bone morphogenetic protein 2 (BMP2) in VICs. In vivo, aortic valve disease was constructed by direct wire injury (DWI), and we showed that overexpression of LMNA by adeno-associated virus significantly decelerated the progression of aortic valve lesion induced by DWI in mice. Conclusion: Excessive mechanical stress can induce damage to the nuclear envelope of AVICs by causing cytoskeletal remodeling, initiating the formation of Z-DNA, and hastening the calcification process in AVICs and CAVD.

Bactericidal effect of far ultraviolet-C irradiation at 222 nm against bacterial peritonitis.

Far ultraviolet-C irradiation at 222 nm has potent bactericidal effects against severe infections such as peritonitis, with minimal cytotoxicity. Bacterial peritonitis due to bowel perforation is a serious condition with high mortality despite current treatments. This study investigated the safety and efficacy of intraperitoneal far ultraviolet-C irradiation at 222 nm. In vitro experiments optimized the fluid conditions for bacterial or protein concentrations prior to in vivo evaluation. In vivo efficacy was assessed in a rat peritonitis model induced by Escherichia coli, measuring intra-abdominal bacterial concentration, blood cytokine levels, and mortality rates. Safety was evaluated by analyzing cyclobutane pyrimidine dimers as markers of DNA damage in five abdominal organs: stomach, small intestine, colon, liver, and spleen. Statistical analyses employed parametric methods for normally distributed data and non-parametric methods for data without normality. Optimal in vitro conditions included 106 CFU/mL bacteria, 0.5 mW/cm2 irradiation, and 10-3 mg/mL protein. In the rat model, far ultraviolet-C irradiation at 222 nm significantly decreased intra-abdominal bacteria, reduced blood cytokines (interleukin-1β and interleukin-6), and elevated survival rates from 20% to 60%, compared to lavage alone. The formation of cyclobutane pyrimidine dimers was significantly lower with 222 nm irradiation than with 254 nm, suggesting reduced DNA damage. These findings indicate that far ultraviolet-C irradiation at 222 nm, when combined with lavage, represents a promising therapeutic strategy for bacterial peritonitis, providing effective bacterial reduction and a favorable safety profile. Further research is needed to verify these findings and investigate long-term safety and potential clinical applications.

Evaluation of different electrolytic solution composition on the microstructure and corrosion study on AZ31 magnesium alloy using PEO method

Abstract Magnesium (Mg) and its alloys are widely used in orthopedic implants due to their mechanical compatibility with bone tissue. However, their susceptibility to corrosion can compromise mechanical strength over time. The present study aims to enhance the corrosion resistance of AZ31 Mg alloy through Plasma Electrolytic Oxidation (PEO) coatings incorporating Hydroxyapatite (HAP). The effects of 5g of HAP in different electrolytic solutions—Sodium Silicate (Na2SiO39H2O) + Potassium Hydroxide (KOH) and Sodium Phosphate (Na3PO4) + Triethanolamine (C6H15NO3)—on the microstructure and corrosion characteristics were evaluated. The phase composition was analyzed using x-ray Diffraction (XRD) and Energy Dispersive Spectroscopy (EDS), while the surface morphology and cross-section of the coatings were assessed using Field Emission Scanning Electron Microscopy (FESEM). Corrosion studies were performed using Potentiodynamic Polarization (PDP) and Electrochemical Impedance Spectroscopy (EIS) under Simulated Body Fluid (SBF) conditions. The results showed that the sample with the solution containing 5 g of HAP + Na3PO4 + C6H15NO3 (PS-2) exhibited superior anti-corrosion properties compared to the sample with 5 g of HAP + Na2SiO3·9H2O + KOH (PS-1). Notably, the cross-sectional analysis revealed significantly smaller pores in the PS-2 coatings. Among the two coated samples, the highest polarization resistance of 3.06 × 106 Ω·cm2 was observed for PS-1, while PS-2 showed a lower resistance of 2.9 × 106 Ω·cm2, correlating with their morphological characteristics. These findings suggest that sodium phosphate and triethanolamine improve biocompatibility when combined with pure AZ31 Mg alloy and HAP coatings.

Brittle Regime Slip Partitioned Damage and Deformation Mechanisms Along the Eastern Denali Fault Zone in Southwestern Yukon

AbstractRare bedrock exposures of the eastern Denali fault zone in southwestern Yukon allow for the measurement, sampling, and analyses of brittle regime fault slip data and deformation mechanisms to explore relations to far field, oblique plate motions. Host rock lithologies and associated slip surfaces show episodic damage zone‐related deformation and calcite ± hematite ± chlorite related hydrothermal fluid flow. This regional scale network of asymmetric fault damage is spatially and kinematically linked to a discrete and narrow fault core. Fault network observations, orientations, slip data, and strain inversions document a slip partitioned strike‐slip fault system with locally and mutually overprinting strike‐, oblique‐, and dip‐slip components. Microstructural analyses reveal crystal plastic and co‐seismic brittle deformation mechanisms active in a narrow range of upper crustal temperature, pressure, fluid, and chemical conditions. The net damage related slip is not exclusively formed by a single kinematic system, but rather a fully partitioned, time integrated system likely operative for much of the fault's brittle regime evolution temporally constrained by previously published thermochronometric data. Although the fault slip data was collected from outcrop‐scale exposures at sites tens of kilometers apart, results show remarkable correlation between fault kinematics and plate motions along the ∼580 km long eastern Denali fault segment. End member, subhorizontal, northeast directed reverse and north directed dextral strike slip fault strain axes closely reflect relative plate motion interactions over at least the last 30 m.y. and act as a proxy for far‐field stresses compatible with the kinematics of the damage zone network.

Application of FLAIR technology in evaluation of complex fluids—Taking M structure of Huizhou sag as an example

Abstract Due to the complexity of reservoir fluid types and the difficulty in identifying hydrocarbon abundance in M structure of the Huizhou sag, the conventional gas logging methods are affected by instrument accuracy, resulting in indistrument difference in gas logging response characteristics. Consequently, the traditional evaluation methoda are inadequate.To address these challenges, fluid logging &amp; analysis in real time technology(FLAIR) is applied. This technology quantifies various gas components by detecting the ion mass, offering advantages such as precise detection and wide measurement range.In this paper,the data of FLAIR technology was analyzed. Based on the differences in hydrocarbon components of various fluids, fluid identification charts were developed using the hydrocarbon component ratio, humidity ratio (WH) and equilibrium ratio (BH) parameters, which could effectively distinguish complex fluids such as gas, condensate, oil and volatile oil formations.The oil index and gas index were selected, and the gas-oil ratio index was formulated. A relationship model between this parameter and the gas-oil ratio data, measured through cable sampling and formation testing was established, enabling the prediction of gas-oil ratio data during drilling. By correcting gas data to reduce the influence of factors such as drilling time, displacement volume and bit size through gas data correction, the evaluation chart of oil and gas abundance, based on the anomaly ratio of gas measurement can adress the evaluation challenges of buried hill reservoir. The aforementioned method provides robust technical support for reservoir fluid identification and evaluation in M structure of Huizhou sag, and has significant application value in complex reservoirs and complex fluid conditions.

Dynamic Response of a Rotor Supported on Hybrid Bearings in Air, Water, and Liquid Nitrogen: Measurements and Comparisons to Predictions

Abstract Modern liquid rocket engine turbopumps implement hybrid bearings, which combine hydrostatic and hydrodynamic fluid film principles, in compact and lightweight units known for their superior reusability, durability, and reliability. This study aims to provide extensive and reliable test data for the purpose of anchoring and benchmarking predictive tools for these bearings. This paper provides comprehensive dynamic response measurements of a rotor weighing 10.40 kg and approximately 60 mm in diameter at the bearing locations. The test rotor is supported on two hybrid journal bearings with a bearing length to bearing diameter ratio of approximately 0.42 and a bearing radial clearance to rotor radius ratio of around 0.0017. The bearings are tested with air, water, and liquid nitrogen, serving as surrogate test fluids for common propellants in liquid rocket engines. Rotor run-up and speed coast-down tests are conducted to measure shaft motion responses. The results clearly demonstrate that the rotordynamic characteristics of the test rotor supported on the hybrid journal bearings largely rely on properties of the test fluids and their feeding conditions. Notably, when air is pressurized into the test bearings, the shaft motion responses differ markedly from those observed with water and liquid nitrogen, primarily due to significantly lower stiffness and damping coefficients. Furthermore, rotor speed coast-down tests for each test fluid exhibit notable differences in coast-down speed over time characteristics, depending on the test fluid properties. The predicted rotor imbalance responses exhibit excellent correlation with the measurement data. The steady increase of demand and growth of the fluid film bearing technology for reusable rocket engines require accurate bearing design tools, the extensive component testing, and the implementation of the technology. The validated and developed bearing predictive models from previous research demonstrate well the characteristics of bearings under various operating fluids conditions. The findings and database presented in this work contribute not only to comprehending the performance of hybrid bearings but also to understanding and enhancing the dynamic characteristics of rotor systems supported on hybrid bearings.