Stability Assessment Research Articles

Scenario‐Based Volcano Slope Stability Hazard Analysis: Case Study of Augustine Volcano, Alaska

AbstractVolcanoes worldwide have undergone cyclic destruction of their edifices, generating catastrophic volcanic debris avalanches. Augustine Volcano in Alaska, USA, has a history of debris avalanches, causing cyclic destruction of the edifice and cascading hazards. These collapses, together with eruption‐related changes in the edifice structure, change the slope stability hazard of the volcano over time. This study aims to develop a current view of the slope stability hazard at Augustine Volcano by (a) characterizing collapse‐prone source areas on the edifice under various scenarios typical of dynamic volcanic environments and (b) identifying the controlling factors that underlie the slope stability hazard. Scenario‐based slope stability assessment was conducted using a quasi‐3D limit equilibrium method to test for the effect of various factors that drive or resist failure, including topography, shallow edifice structure, strength of edifice‐forming materials, pore fluid pressure distribution, and local and regional seismicity. Results show that in all scenarios assessed, the slopes of Augustine Volcano are stable with a factor of safety (FOS) greater than 1. The FOS, however, decreases with decreasing strength of edifice‐forming materials, pore fluid pressurization, and earthquake loading. The location of the relatively less stable slope, changes to the southwestern flank when accounting for subsurface heterogeneities derived from geophysical observations. Subsurface heterogeneity is thus a key underlying factor, along with steep topography, in controlling where collapse‐prone source areas occur, and it should be accounted for in volcanic slope stability hazard assessments.

Application of limit equilibrium and shear strength reduction techniques for stability assessment of slope cuts- A case study of Khalid-Dijo dam project, Southern Ethiopia

Dam failure can occur due to foundation instability, downstream and upstream slopes instabilities. This study assesses the stability of upstream and downstream slope cuts at Khalid-Dijo irrigation dam project, which is located in Southern Ethiopia, 3km south of Werabe town. Limit equilibrium and finite element shear strength reduction methods are adopted. Validation of results and comparisons between those methods are carried out. The analysis considers anticipated site conditions, including static dry, static saturated, dynamic dry and dynamic saturated conditions. Slope material properties are measured from insitu, laboratory tests and used as input parameters for the analysis to obtain factor of safety and critical strength reduction factors. The properties considered in the analysis include unit weight, cohesion, angle of internal friction, poison’s ratio, dilation angle and Young’s modulus. The analysis indicates that the factor of safety values for limit equilibrium methods and the critical strength reduction factor for finite element method are very similar across the three slope cuts under all anticipated conditions. The lowest factor of safety and critical strength reduction factor is 1.56 and 2.07 respectively. Generally, the proposed dam project is safe against upstream and downstream slope failures. These studies suggest that maintained the average safety factor values of both methods during the design stage are crucial to avoid unnecessary risk.

Clinical correlates of lifetime and current comorbidity patterns in autoimmune and inflammatory diseases

BackgroundAutoimmune and inflammatory diseases (AIDs) are a heterogeneous group of disorders with diverse etiopathogenic mechanisms. This study explores the potential utility of family history, together with present and past comorbidities, in identifying distinct etiopathogenic subgroups. This approach may facilitate more accurate diagnosis, prognosis and personalized therapy. MethodsWe performed a multiple correspondence analysis on patients' comorbidities, followed by hierarchical principal component clustering of clinical data from 48 healthy volunteers and 327 patients with at least one of 19 selected AIDs included in the TRANSIMMUNOM cross-sectional study. ResultsWe identified three distinct clusters characterized by: 1) the absence of comorbidities, 2) polyautoimmunity, and 3) polyinflammation. These clusters were further distinguished by specific comorbidities and biological parameters. Autoantibodies, allergies, and viral infections characterized the polyautoimmunity cluster, while older age, BMI, depression, cancer, hypertension, periodontal disease, and dyslipidemia characterized the polyinflammation cluster. Rheumatoid arthritis patients were distributed across all three clusters. They had higher DAS28 and prevalence of extra-articular manifestations when belonging to the polyinflammation and polyautoimmunity clusters, and also lower ACPA and RF seropositivity and higher pain scores within the polyinflammation cluster. We developed a model allowing to classify AID patients into comorbidity clusters. ConclusionsIn this study, we have uncovered three distinct comorbidity profiles among AID patients. These profiles suggest the presence of distinct etiopathogenic mechanisms underlying these subgroups. Validation, longitudinal stability assessment, and exploration of their impact on therapy efficacy are needed for a comprehensive understanding of their potential role in personalized medicine.

Environmentally Benign High‐Performance Composites‐Based Hybrid Microcrystalline Cellulose/Graphene Oxide

ABSTRACTA novel silane functionalization prepared by a solution mixing approach of epoxy composites filled with eco‐friendly reinforcement filler, that is, graphene oxide (GO) and microcrystalline cellulose (MCC). The developed composites were subjected to comprehensive analysis using various characterization techniques, encompassing mechanical testing, water absorption analysis, thermal stability assessment, and scanning electron microscopy (SEM). The tensile strength and Young's Modulus of the epoxy composite filled with 1.0 wt.% of GO (EGO1.0) demonstrated the highest value viz. 29.83 MPa and 1991.71 MPa, respectively, when compared to neat epoxy composite (E0). Meanwhile, the thermal gravimetry analysis (TGA) studies, particularly char yield, highlight improvements in the thermal stability of the EGO2.5 composite, that is, 23.39% representing a 33.73% increment compared to the E0 composite. The synergistic effect of hybrid filler, achieved by a combination of micro and nanoparticle fillers within an epoxy matrix, was investigated as a virtuous alternative to the conventional epoxy nanocomposites. A uniform dispersion of GO on the MCC surface leads to significant improvements in the mechanical properties and thermal stability of the epoxy‐reinforced composite. The maximum tensile strength, Young's Modulus, and break strain of 39.77 MPa, 2591.27 MPa, and 2.90%, respectively, were observed for the modified EGO1.0MCC1.5 composite. The synergistic effect of hybrid eco‐friendly reinforcement fillers (GO/MCC) and a strong interfacial adhesion between the matrix and filler reduces the formation of defects, thereby resulting in good stress transfer from matrix to fillers.

Does the application of Jensen's integral inequality and LMIs confirm exponential stability in delayed systems with gapped gamma distribution through augmented Lyapunov function?

This study is dedicated to a comprehensive exploration aimed at advancing our understanding of stability within dynamic systems. The focus is particularly on the intricate domain of delayed systems characterized by gapped gamma distributions. The primary objective of this investigation revolves around evaluating the pragmatic application and efficacy of Jensen's integral inequality in combination with the powerful analytical tools provided by Linear Matrix Inequalities (LMIs). This evaluation is crucial for rigorously assessing exponential stability within these complex systems. Central to our investigative framework is the strategic deployment of augmented Lyapunov functions. These functions play a crucial role in unraveling the intricate stability properties of delayed systems featuring gapped gamma distributions, allowing for a nuanced examination of their inherent stability characteristics under various conditions. The mathematical formulation crafted in this exploration intricately captures the interplay between the distinctive attributes of the gapped gamma distribution and the complex dynamics of the loop traffic flow model within the overarching delayed system. This interconnection serves as the fundamental basis for the stability analysis, providing insights into the interdependence of these key elements. The noteworthy contribution of this study lies in the systematic construction of a robust analytical framework explicitly tailored for stability assessment. A comprehensive investigation is undertaken to elucidate critical aspects, including the convergence rate and the attainment of asymptotic stability within the considered delayed system. Additionally, a dedicated simulation section, focusing on Vehicle Active Suspension Control, has been incorporated to further validate and showcase the applicability of the proposed methodology.

Certification and Long-Term Stability Assessments of 5-Methyltetrahydrofolate in Spinach and Kimchi Cabbage Certified Reference Materials Using Tri-enzyme Method and Isotope Dilution Ultra-performance Liquid Chromatography/Tandem Mass Spectrometry

Certification and Long-Term Stability Assessments of 5-Methyltetrahydrofolate in Spinach and Kimchi Cabbage Certified Reference Materials Using Tri-enzyme Method and Isotope Dilution Ultra-performance Liquid Chromatography/Tandem Mass Spectrometry

CREDIT MANAGEMENT STRATEGY TO ENSURE THE FINANCIAL STABILITY OF PACKAGING INDUSTRY ENTERPRISES

The article examines the possibilities of increasing the efficiency of credit resource management to ensure the financial stability of enterprises in the packaging industry. It was found that in modern conditions, the study of the assessment of the financial stability of the enterprise was not of a comprehensive nature, but was based, mainly, on the use of the coefficient method, which took place on a static basis and did not take into account the specifics of the industry, did not make it possible to assess the ability of the enterprise to generate cash flows for the implementation of activities. It has been proven that the problem of ensuring financial stability and financial balance of packaging industry enterprises is now an important one, especially in the conditions of uncertainty and instability of the economic environment caused by the war. On the basis of the conducted research, the key factors on which an effective credit management strategy should be based have been determined. In this context, the special importance of a timely and objective assessment of the financial stability of enterprises in the packaging industry, regardless of the forms of their ownership, is emphasized, which should be aimed at finding ways and opportunities to increase profits by means of a timely analysis of the financial state of enterprises. Eleven factors are proposed that should be taken into account when choosing a financial credit institution. A systematic analysis of the financial condition of the enterprise, its solvency, liquidity and financial stability is also necessary because the profitability of any enterprise largely depends on its solvency. Based on the balance sheet plan of the necessary resources, we forecast the sources of their formation, taking into account the level of financial leverage and the funds saved as a result of this at the time of taxation. Choosing the most profitable parameters, the enterprise can immediately determine the directions of saving its own monetary and financial resources, as well as optimize the use of already received ones. It has been established that in modern conditions, the relevance of effective financial management as a system of timely methods and techniques capable of preventing a financial crisis and avoiding risks of loss of financial stability of the enterprise in the future is objectively increasing. The lack of a clear definition of financial stability as an economic category and a system of indicators for its assessment, which requires further theoretical development of the problem.

Thermal regime of peatlands in Western Siberia near the southern border of the permafrost

Relevance. The permafrost degradation under the effect of global warming. It determines the necessity for a predictive assessment of permafrost stability to minimize disturbances to engineering installations in the permafrost zone. Aim. To assess the stability of frozen peatlands in the southern part of the zone of insular distribution of permafrost. Objects. Soils of flat-mound and high-mound palsa mires, which preserve permafrost on the southern border of the insular permafrost zone. Methods. Measurements of the temperature of peat and mineral soil in geocryological boreholes from 0 to 10 m deep using the SAM-N automatic monitoring surveillance network; determination of surface temperature from thermal channels of MODIS satellite images from 2000 to 2022; analysis of meteorological indices and determination of air temperature trends for predictive assessment of permafrost stability; calculation of indicator values of permafrost state, such as freezing degree-days and thawing degree-days, frost index, freezing and thawing N-factors. Results. Numerous features of unstable permafrost have been observed. In particular, the mean annual temperature of the surface layer was positive in all studied boreholes (+0.8...+1.3°C), and the temperature at the depth of zero amplitudes (10 m) is close to the melting point (with the predominance of temperatures in the range of –0.2...–0.3°C). Besides, a layer of soil that does not freeze throughout the year (non-merging permafrost) was identified. The thawing degree-days and frost number values correspond to areas with unfrozen soils. Positive trends in air temperature, Earth's surface temperature, and snow depth were observed. For 2000–2022, surface air temperature increased by 0.76°C/10 years on average. The land surface temperature increased in summer by an average of 0.42°C/10 years. If the positive trend in surface air temperatures continues, frozen peatlands in the southern part of the permafrost zone will completely melt in 50–70 years.

Building a system of indicators of stability and sustainability of industrial enterprise production system functioning

Subject. The article deals with the development of a system of indicators of stability and sustainability of production system functioning at industrial enterprises. Objectives. The aim is to develop a methodological approach to the formation of a system of indicators for operational assessment of production system stability, and sustainability of its functioning. Methods. We employ methods of analyzing the existing approaches to assessment of stability and sustainability of enterprise production system, their generalization, and synthesis of a system of indicators characterizing the impact of the most critical production risks on the production system. Results. The paper offers a methodological approach to the formation of the said system of indicators, underpins the need to assess stability and sustainability of production system functioning, introduces an indicator of stability reserve of production system functioning that enables to assess the level of stability of production system operation. Conclusions. The proposed methodological approach makes it possible to develop management solutions aimed at restoring the stability of the functioning of an industrial enterprise.

Magnetostratigraphy of the upper Jurassic and Lower Cretaceous deposits of the Bolshekhetskaya structural terrace

Relevance. The confinement of hydrocarbon deposits to certain stratigraphic horizons, poor knowledge of the northeast of Western Siberia and adjacent territories, including the magnetostratigraphic method, with their oil and gas potential (over the past 10 years, four unique hydrocarbon deposits have been discovered here), the boreal nature of the deposits, and the need for remote magnetostratigraphic correlations. Aim. To create a magnetostratigraphic reference section of the northeast of Western Siberia. Objects. Sections of deep wells of the Pendomayakhskaya, Vostochno Suzunskaya, Vostochno Lodochnaya and Gorchinskaya areas of the Bolshekhetskaya structural terrace, which exposed the Lower Cretaceous and upper parts of the Upper Jurassic (Yanovstan Formation) deposits. Methods. Paleomagnetic studies were carried out according to standard methods and included sampling of core samples with an "up-down" orientation, sample preparation (kappametry, marking of samples, photographing, sawing), measurement of magnetic susceptibility, temporary cleaning (the samples were located along the field during a week, then a week-against the field with determination of residual magnetization), complete demagnetization by alternating magnetic field, plotting of complete demagnetization, mass cleaning, determination of components of natural residual magnetization, assessment of paleomagnetic stability, identification of forward and reverse polarity zones, construction of paleomagnetic sections. To construct the magnetostratigraphic sections given in this article, the paleomagnetic and biostratigraphic data are linked. For this purpose, magnetochrons were identified using biostratigraphic analysis. Results. The authors have compiled a composite magnetostratigraphic section of the boundary Jurassic-Cretaceous deposits of the Bolshekhetskaya structural terrace and identified four magnetozones with subzones of direct and reverse polarity, compared with the Berriasian ammonite scale. The high information content of the results of magnetostratigraphy research under boreal conditions was noted.

Assessment of housekeeping genes stability for gene transcription regulation analysis of Spodoptera littoralis (Lepidoptera: Noctuidae) under Spodoptera littoralis nucleopolyhedrovirus viral infection.

Normalization with respect to stable housekeeping genes is important to facilitate gene transcription regulation research and acquire more accurate quantitative polymerase chain reaction (qPCR) data. In the current study, five candidates housekeeping genes of the cotton leafworm, Spodoptera littoralis encoding for Actin (Actin), elongation factor 1-alpha (EF1α), ribosomal protein S3 (RPS3), ribosomal protein 49 (RP49), and Ubiquitin (Ubi), were evaluated as normalization housekeeping genes under Spodoptera littoralis nucleopolyhedrovirus (SpliNPV) viral infection. The qPCR results confirmed the expression of all five housekeeping genes in S. littoralis viral infected larvae. The expression profiles of the housekeeping genes showed that the EF1α, Actin, and RP49 had the minimum average Ct values of 18.41 ± 0.66, 18.84 ± 0.90 and 19.01 ± 0.87 in all infected samples, respectively. While RPS3 and Ubi showed the maximum average Ct of 21.61 ± 0.51 and 21.11 ± 0.82, respectively. According to the results of ΔCt and geNorm analysis, EF1α was ranked as the most stable housekeeping gene during infection time-course. While by using BestKeeper, geNorm and NormFinder, the Ubi, RP49, and RPS3 showed the most genes transcription stability. The obtained results were also validated using the Cytochrome c oxidase (COX) gene transcripts in response to SpliNPV infection. The results revealed that EF1α and Ubi were the most stable housekeeping genes to be used for normalizing S. littoralis gene transcription regulation under SpliNPV infection. These findings, provide a significant addition for gene transcription regulation studies of S. littoralis upon infection using SpliNPV as a bio-agent.

Comparative Analysis for Bejerman Versus Kinematic Methods for Slope Stability Assessment

In a previous study, the stability of eleven Haibat Sultan Road Crossing stations was assessed using Bejerman's Method. Amongst these 11 studied stations with the highest potential for slope failures, four stations (4, 5, 6, and 9) could be evaluated using kinematic analyses in another previous paper. This study focused on comparing the analysis results of these four stations using the Kinematic Method with those assessed by Bejerman’s Method. The outcome showed negative relations, whereby an inverse correlation between the Landslide Possibility Index and the Factor of Safety has been found. Such a comparison enables us to use extrapolations to analyze the missing data. Both sets of data from the two methods of analysis, which were obtained by the two methods, were collected, compared, and discussed.

Assessment of landslide Possibility Index and Rockfall Hazard Rating System for Slopes in Qaywan Mountain, Sulaimani Governorate, Northeastern Iraq

The current study includes assessing road risks using a system Landslide Possibility Index (LPI) and Rockfall Hazard Rating System (RHRS) analysis along the Qaywan Mountain (anticline) main road 20 km north of SulaimaniGovernorate. Slope stability assessments consisted of seventeen stations along the main road in the study area. Along the outcropped rock units represented by formations, Balambo, Sarmord, Kometan, and Shiranish, a thorough discontinuity assessment and a regional survey of slopes were carried out. Along the cut slopes, rockfall is the primary type of failure, in addition to possibility types of landslide failures in the studied area is plane sliding, wedge sliding, and toppling because cutting rocks to build roads, slope direction and slope angle, dip and dip direction of discontinuities. The (LPI) indicates all the slopes studied in 17 sites in the surveyed area along the road were classified as high hazard. According to the analysis results of the RHRS, the score ranges between 177 and 375. Site no. 5 (375) has the highest rating value indicating a moderate hazard that requires remedial measures to be taken with a moderate level of urgency and site no.8 has the lowest value noted (177). It is the only site that falls under this rating, which is classified as a low hazard and slopes do not require detailed studies.

ON THE CHAOTIC NATURE OF A CAPUTO FRACTIONAL MATHEMATICAL MODEL OF CANCER AND ITS CROSSOVER BEHAVIORS

In this paper, a three-dimensional mathematical model of cancer, incorporating tumor cells, host normal cells, and effector immune cells, is examined. The chaotic nature of this cancer model is explored within the framework of Caputo fractional calculus. The analysis employs local stability assessment using the Matignon criteria, Lyapunov exponents (LEs) for various fractional orders of derivatives, bifurcation plots reflecting changes in the fractional derivative order, simulation outcomes of a novel chaotic attractor, Kaplan–Yorke dimension, and sensitivity to initial conditions. The results demonstrate that the Caputo fractional cancer model exhibits chaotic behavior for selected parameters. Moreover, the fractional derivative orders significantly influence the extent of chaotic behavior. Specifically, as the fractional derivative order increases from zero to one, the intensity of chaos diminishes, evidenced by a decrease in both the LE and the Kaplan–Yorke dimension. A piecewise modeling approach is applied to the cancer model, incorporating deterministic, stochastic, and power-law behaviors. Three distinct scenarios are developed within this framework, revealing several novel crossover behaviors through simulation. Notably, it is observed that when cancer dynamics initially follow a power-law behavior and subsequently transition into a stochastic process, the disease dynamics can stabilize, suggesting a positive outlook for disease control. Conversely, if the cancer dynamics begin with a deterministic process and then shift to a stochastic process, the system may enter a chaotic state, complicating disease management efforts.

Using well log data to predict rock compressibility and elasticity in Zubair formation/ southern of Iraq

The mechanical characteristics of rocks such as elasticity (Young's modulus, Poisson's ratio, and unconfined compressive strength) play an essential in sand production analysis, well design, and borehole stability assessment. In this study, the mechanical characteristics of rocks were indirectly estimated using gamma ray, density, and acoustic (compressional and shear) log data from well RU-X in the Rumaila oil field, specifically for the Zubair Formation. These estimated properties were compared to direct measurements obtained from triaxial and uniaxial mechanical tests conducted on well RU-X. The results showed a significant similarity between the indirect estimates and the direct measurements, indicating their reliability for sand production analysis and their valuable contribution to constructing the geomechanical model. Moreover, the static profile of Poisson's ratio was validated using laboratory core test results, demonstrating reasonable agreement. The validation process involved comparing laboratory-derived measurements with actual field measurements in the Zubair Formation. The higher Poisson's ratio observed in the shale was attributed to the slower propagation of acoustic waves, resulting in a good matching with an R2 value of 0.77. On the other hand, the lower Young's modulus in the shaly formations indicated lower resistance to deformation, with a comparative ratio of R²=0.96. Static measurements, which consider various influencing factors, provide a more realistic representation of rock behavior under different conditions. Regarding unconfined compressive strength, the comparative ratio was R²=0.83.

Significant implications of diversity and stability for ecosystem sustainability necessitate differentiated management strategies: A case study of the urban agglomeration around Hangzhou Bay, China (JEMA-D-24-12476R1)

Ecosystems are crucial for providing essential services, supporting ecological conservation, and promoting sustainable development on both regional and global scales. However, robust methodologies and comprehensive frameworks for assessing ecosystem sustainability are still lacking. This study presents an integrated framework that incorporates both diversity and stability in evaluating ecosystem sustainability. Our methodology involves a multi-step process: first, we select and integrate landscape metrics to quantify ecosystem diversity; second, we establish an ecological network and apply a robustness model to assess ecosystem stability; finally, we delineate zones of ecosystem sustainability based on the combined assessments of diversity and stability. Our findings reveal that (1) from 1995 to 2020, ecosystem diversity significantly increased within the urban agglomeration around Hangzhou Bay (UAHB), with notable regional patterns, particularly in Huzhou, Jiaxing, and Ningbo. (2) The structure and connectivity of the ecological network have markedly improved, with network robustness in 2020 surpassing that of 1995, indicating enhanced ecosystem stability. (3) Five distinct ecological zones were identified—high sustainability protected areas, ecosystem stability improving areas, low sustainability fragile areas, ecosystem diversity improving areas, and moderate sustainability transition areas—each accompanied by specific management strategies. This research offers theoretical insights and practical guidance for ecological protection and restoration, advancing sustainable ecosystem development.

Two branches solutions for mixed convection flow of thermally Williamson nanofluid flow with heat transfer due to magnetized shrinking sheet

AbstractThe study of magnetohydrodynamics (MHD) and thermal radiation over‐stretching and shrinking sheets has significant applications in a wide range of fields, from chemical manufacturing to transport engine cooling systems, electronic chip cooling, plasma, the nuclear‐powered sector, saltwater, etc. The present study aims to numerically and theoretically analyze the movement of thermally magnetized Williamson nanofluid owing to an extended/contracting sheet. The regulating flow equations are converted to self‐similar equations through similarity transformation, and then numerically solved by bvp4c using MATLAB software. A comparison of the present numerical study with the published study is quite impressive. The investigation demonstrates that the self‐similar equations disclose the two branches for the limited shrinking factor range. For the stretching case, only one solution exists. As a result, the most fundamentally feasible solution has been determined by the linear assessment of temporal stability. For the aim of stability analysis, the lowest eigenvalue sign indicates the stability or instability of a solution. Through stability analysis, it is witnessed that the first solution (first branch) is stable. Due to the presence of the Lorentz force effect, it is perceived that the velocity curves decline in the whole channel. The point to be noted here is that the velocity of the lower branch compared to the upper branch is higher. The reduced Skin Friction is increased in the first branch and declines in the second branch for the two different values of magnetic factor.

Cerebellar tDCS combined with augmented reality treadmill for freezing of gait in Parkinson's disease: a randomized controlled trial.

Parkinson's disease (PD) is often accompanied by gait disorders and freezing of gait (FoG), disabling symptoms that are resistant to conventional dopamine treatments. Given the cerebellum's connectivity with the motor cortex and basal ganglia, and its implication in PD, combining transcranial direct current stimulation targeting the cerebellum (ctDCS) with physical exercise might improve gait and balance. This study aimed to evaluate the effectiveness of a novel rehabilitation approach that combines noninvasive cerebellar stimulation with motor-cognitive training via an augmented reality treadmill (C-Mill VR+) in individuals with PD and FoG. Seventeen individuals with PD exhibiting FoG were enrolled in a randomized controlled trial. The participants were randomly assigned to a group receiving motor-cognitive training on the C-Mill VR+ with either ctDCS or sham ctDCS. Assessments were conducted pre-intervention (T0), post-intervention (T1) after 10 sessions, and at 4-week follow-up (T2), using various clinical scales. Additionally, C-Mill assessments of postural stability and gait were conducted at T0 and T1. Although no significant time*group interactions were observed for any of the clinical variables measured, some were found in the C-Mill measures. Specifically, right lower limb sway in static conditions, both with eyes open (OAD) and eyes closed (OCD), significantly improved at T1 in the ctDCS group compared with the sham group. C-Mill outcomes indicate that the combined treatment may enhance motor control. Participants who received ctDCS along with augmented reality motor-cognitive training showed better postural stability.

Synthesis and characterization of nickel cobaltite–supported film for hexavalent chromium photocatalytic reduction

ABSTRACT Hexavalent chromium (Cr(VI)) is a prevalent and highly toxic pollutant, posing a serious threat to human health and ecosystems. This study addresses this issue by exploring the photocatalytic reduction of Cr(VI) using hydrothermally synthesized nickel cobaltite (NiCo2O4) spinel–supported films. The research fills the gap for efficient visible light photocatalytic materials for Cr(VI) reduction, with the aim to synthesize, characterize, and assess NiCo2O4-supported films’ photocatalytic activity. Synthesis was achieved via a hydrothermal method on fluorine-doped tin oxide (FTO) and titanium dioxide (TiO2) over FTO substrate. The films were characterized using several techniques and their photocatalytic activity was tested under UV-A and visible light, with Cr(VI) concentration monitored periodically up to 240 min. The NiCo2O4/TiO2 film demonstrated superior photoreduction performance under both UV and visible light radiation compared to TiO2 and NiCo2O4, achieving photoreduction of Cr(VI) by 76% under UV light with a rate constant of 5.79 × 10−3 min−1 and 60% under visible light with a rate constant of 4.74 × 10−3 min−1. In conclusion, hydrothermally synthesized NiCo2O4/TiO2 film shows promising photocatalytic performance for Cr(VI) reduction, marking a significant advancement in photocatalysis and water treatment technologies. Future research will focus on stability assessment, synthesis process optimization, and real-world water treatment application.

An AUV stability estimation method by considering rudder design parameters

Stability is a critical characteristic of Autonomous Underwater Vehicles (AUVs). During the initial design stage, selecting an appropriate rudder design is essential to ensure the overall stability performance of the AUV. This study introduces a method for predicting the stability of AUVs equipped with different rudder configurations. By parametric modeling based on the geometric characteristics of X-rudders, the rudder area, aspect ratio, and position parameters, which significantly impact AUV stability, were selected as the primary research objects. Formulas were derived to estimate the associated hydrodynamic forces and moments critical for assessing the stability index. Validation of this approach is conducted through comparison with Computational Fluid Dynamics (CFD) simulations. The results show that this method effectively predicts the hydrodynamic behavior of AUVs, facilitating stability assessments across various rudder designs.