Change Of Direction Research Articles

Development And Application Of A New Visualization Technique Using Photochromism For Transport Process Of Lubricating Oil Around The Engine Piston

A new visualization technique using photochromism for the movement of oil film was developed and applied to an optical gasoline engine. A photochromic dye was dissolved in the oil and an arbitrary position of the oil film was illuminated by UV laser light, which makes a marker in the oil film via a photochromic reaction. The lifetime of color change by photochromism is relatively long and therefore, by tracking the movement of a marker makes it possible to visualize the movement of oil film directly. The color density was quantified based on the absorbance calculated from images taken before and after coloring in two wavelengths. Through the experimental and theoretical considerations, it was confirmed that the calculated absorbance is effective in reducing a noise originated by the color, the shape of the piston surface, the temporal variation of oil film thickness and the illuminating light intensity distribution. Furthermore, the value of the absorbance is in a very good linear relationship with the oil film thickness. This technique was applied to an optical gasoline engine and confirmed the availability of this technique. In the top land of piston surface, the oil film between the piston and cylinder liner was separated and the majority of the oil is at the piston surface and moved with the piston motion. The oil film thickness on the cylinder liner was very thin. On the contrary, at the piston skirt region, a wider region of the oil film is connected between the linear and the piston skirt. However, there are regions where the oil film between the liner and the skirt is separated by cavitation and the majority of the oil film is on the piston skirt. The change of the flow direction by the operating condition, i.e., the throttle condition, was able to clearly visualize, though the movement of oil film on the piston surface was very slow in normal case. The relatively fast complexed flow for opposite direction was also able to visualize by this technique.

High-Performance 2D Ambipolar MoTe2 Lateral Memristors by Mild Oxidation.

2D transition metal dichalcogenides (TMDCs) have been intensively explored in memristors for brain-inspired computing. Oxidation, which is usually unavoidable and harmful in 2D TMDCs, could also be used to enhance their memristive performances. However, it is still unclear how oxidation affects the resistive switching behaviors of 2D ambipolar TMDCs. In this work, a mild oxidation strategy is developed to greatly enhance the resistive switching ratio of ambipolar 2H-MoTe2 lateral memristors by more than 10 times. Such an enhancement results from the amplified doping due to O2 and H2O adsorption and the optimization of effective gate voltage distribution by mild oxidation. Moreover, the ambipolarity of 2H-MoTe2 also enables a change of resistive switching direction, which is uncommon in 2D memristors. Consequently, as an artificial synapse, the MoTe2 device exhibits a large dynamic range (≈200) and a good linearity (1.01) in long-term potentiation and depression, as well as a high-accuracy handwritten digit recognition (>96%). This work not only provides a feasible and effective way to enhance the memristive performance of 2D ambipolar materials, but also deepens the understanding of hidden mechanisms for RS behaviors in oxidized 2D materials.

The effect of the Pisa syndrome on balance and gait in Parkinson’s disease: a comparative study

INTRODUCTION. Pisa syndrome is a postural deformity that can lead to impaired posture control and balance in patients with Parkinson’s disease (PD), which increases the risk of injury and reduces the quality of life. AIM. To study the effect of the Pisa syndrome on postural control, balance and gait of patients with Parkinson’s disease. HYPOTHESIS. It is assumed that patients with PD with the Pisa syndrome will have specific features of postural control and balance, which must be taken into account when developing rehabilitation technologies for correcting postural disorders. MATERIALS AND METHODS. As part of the comparative study, 30 people of both sexes were examined, all study participants received levodopa drugs in an individual dosage selected by a neurologist-parkinsonologist. The subjects were divided into 2 groups of 15 people each according to the principle of the presence of the Pisa syndrome and its absence. Criteria for inclusion in the groups: voluntary informed consent of persons with PD for the study; age from 45–80 years, stage 2–4 of Hoehn-Yahr Parkinson’s disease, absence of other diseases and gross cognitive impairment. The diagnosis was carried out using the COBS Physiomed stabilometry system and the EQ-5D-3L questionnaire, a diary of falls and a dynamic gait index (DGI). The reliability of the differences was determined by the Mann-Whitney U-test. Data processing was carried out using the Statistica 10 program. RESULTS. Significant differences were revealed in the parameter of the coordination index of the Standing Balance test for the right leg and on the EQ-5D-3L scale at a significance level of p 0.05, in the group of people with PD without the Pisa syndrome, the quality of life was significantly higher, the number of falls was significantly higher in the group of people suffering from PD with the Pisa syndrome towers. DISCUSSION. Walking with a change of direction and multitasking is the most significant problem for people with PD with the Pisa syndrome, the differences between the groups are significant at a significance level of p 0.01. CONCLUSION. Patients with PD and Pisa syndrome have altered gait associated with body tilt forward, instability and decreased balance control.

Light load jump squat and plyometric training enhance jumping, sprinting, change of direction, and balance performance of male soccer players (U-19): a randomized controlled trial.

In sports science, optimizing athletic performance is pursued through an emerging approach that combined light-loaded squat (LLS) training and plyometric jump training (PJT), targeting strength, power, and neuromuscular adaptations, particularly beneficial for the dynamic demands of youth soccer. The aim of this study was to examine the effect of a combined LLS training and PJT program on athletic performance and balance in youth soccer players. Thirty-two male players were randomly assigned to two groups: an experimental group (EG: N.=16; age: 18.56±0.51 years; body mass: 66.87±4.99 kg; height: 1.78±0.07 m) and a control group (CG: N.=16; age: 18.68±0.47 years; body mass: 67.93±4.58 kg; height: 1.77±0.07 m) from the same U19 team of a professional club voluntarily participated in the study. Squat jump (SJ), countermovement jump (CMJ), horizontal jump (HJ), drop jump (DJ), 30 m sprint (30 mS), change of direction ability (4×5 m sprint test [S 4×5 m]) and static balance (the stork balance) performance tests were carried out in the week before and the week after the 8 weeks with combined LLS and PJT period. The two-way analysis of variance (ANOVA) was used for all tests. The results of this study show that the EG had significantly greater improvements than the CG in all tests (all P<0.001). Also, EG experienced higher performance between preintervention and post intervention measures (all P<0.05). There was no significant difference between the two groups in the 4×5mS performance (P>0.05). We conclude that coaches may be advised to use the combined LLS and PJT since it is as effective as traditional methods and perfect for sports and activities requiring fast, explosive movements during the in-season period than regular training.

The effect of fresh and used ankle taping on lower limb biomechanics in sports specific movements

ObjectivesWe aimed to investigate the effects of ankle taping on lower extremity biomechanics related to injury development and how these effects change after sports-specific use. DesignRandomized, repeated measures design with three conditions: Barefoot, tape applied fresh, and tape after sports-specific use (between-subject factor: sex). MethodsTwenty-five healthy participants (ten female) performed sports-specific movements, including running, drop jumping, and 180° change of direction, under the three conditions. Kinetic and kinematic data were collected using 3D motion capturing and force platforms. ResultsTape applied fresh and tape after sports-specific use significantly reduced peak ankle inversion. Biomechanical risk factors for anterior cruciate ligament or running overuse injuries were either unchanged or decreased with tape applied fresh, except for the peak loading rate of the resultant ground reaction force, which increased between 4% and 18% between movement types. After 15 minutes of sports-specific use of the tape, the alterations induced by tape applied fresh remained for some biomechanical risk factors while they became closer to barefoot again for others, indicating a differential response to prolonged use of taping for different biomechanical variables. ConclusionsAnkle taping protects the ankle joint by reducing biomechanical risk factors associated with ankle sprains, and most biomechanical risk factors for anterior cruciate ligament or running overuse injuries are not increased. Further research is needed to explore the duration of protective effects, variations across sports, and its impact on patients with chronic ankle instability, contributing to a more comprehensive understanding of ankle taping's influence on lower extremity biomechanics.

Assessment of direction changes in waste electrical and electronic equipment management in Poland

A growing amount of waste electrical and electronic equipment (WEEE) indicates the need to verify the effectiveness of its management both nationally and globally. An analysis of the WEEE economy in Poland conducted over 5 years confirmed a 16.64% increase in the mass of collected equipment. The maximum annual mass of electrical and electronic equipment introduced to the market during this period was 607,240 Mg, with the average value exceeding 500,000 Mg. The WEEE category with the largest collected mass was waste code 20 01 36, which exceeded 235,000 Mg, whilst the highest waste weight accumulation rate of 45.98 kg per capita was recorded in one of the smallest voivodeships in Poland. This result showed the diversity of WEEE accumulation on a national scale. Overall, a noticeable increase in the WEEE accumulation rate has occurred as Poland’s gross domestic product has increased, despite a decreasing population. An analysis based on the waste accumulation indicators, including socioeconomic factors, confirmed the need to develop forms of WEEE recovery and recycling to transition to a circular economy and promote the synergy of activities amongst all players in WEEE management.

Study on the deposition characteristics of fine particles at local components in air conditioning ventilation ducts

Air conditioning ventilation ducts are widely used in contemporary buildings. The change of airflow direction in the ducts local components can easily lead to the deposition of particles, which can easily form a secondary source of indoor air pollution and have an adverse effect on human health. Based on this, this paper utilizes the existing experimental data to validate the numerical simulation. The Reynolds stress turbulence model combined with the method of enhanced wall function was used to investigate the deposition characteristics of fine particles in different local components. For the first time, local deposition rates and deposition hotspots were proposed to analyze the simulation results. The results show that the local deposition rate of the particles with a particle size of 1μm do not differ much on each wall surface, and the particles are deposited more uniformly on each wall at the local components, with a difference of less than 10 %, and the maximum local deposition rate is on the outer wall of the local components. When the particle size is larger than 10μm, the local deposition rate on the outer wall of the local component increases significantly, with a maximum increase of 23.3 % (compared to 5μm particles), and the maximum local deposition rate increases slowly with increasing air velocity, with a maximum increase of less than 8 %. The effect of increasing particle size on the maximum local deposition rate is much greater than the increase in air velocity. With the increase of air velocity and particle size, the deposition hotspots of both the 90° bend and the T-type tee duct migrate to the middle of the wall, and the deposition hotspots of the 4-way duct migrate to the inside of the wall.

Gaze and Arrows: Does the Gaze-Following Patch in the Posterior Temporal Cortex Differentiate Social and Symbolic Spatial Cues?

The gaze-following patch (GFP) is located in the posterior temporal cortex and has been described as a cortical module dedicated to processing other people's gaze-direction in a domain-specific manner. Thus, it appears to be the neural correlate of Baron-Cohen's eye direction detector (EDD) which is one of the core modules in his mindreading system-a neurocognitive model for the theory of mind concept. Inspired by Jerry Fodor's ideas on the modularity of the mind, Baron-Cohen proposed that, among other things, the individual modules are domain specific. In the case of the EDD, this means that it exclusively processes eye-like stimuli to extract gaze-direction and that other stimuli, which may carry directional information as well, are processed elsewhere. If the GFP is indeed EDD's neural correlate, it must meet this expectation. To test this, we compared the GFP's BOLD activity during gaze-direction following with the activity during arrow-direction following in the present human fMRI study. Contrary to the expectation based on the assumption of domain specificity, we did not find a differentiation between gaze- and arrow-direction following. In fact, we were not able to reproduce the GFP as presented in the previous studies. A possible explanation is that in the present study-unlike the previous work-the gaze stimuli did not contain an obvious change of direction that represented a visual motion. Hence, the critical stimulus component responsible for the identification of the GFP in the previous experiments might have been visual motion.

Foot health and physical fitness: investigating the interplay among flat feet, body balance, and performance in junior high school students

Background and Study Aim. Foot health and physical fitness in children are closely interconnected, playing a vital role in ensuring their overall well-being and performance. This study aims to determine the relationship between flat feet, body balance, and physical performance of junior high school students. Material and Methods. A total of 109 junior high school students from five schools in Surabaya, Indonesia, with ages ranging from 12 to 14 years, participated in this research. Data collection was through the wet footprint test, stork standing balance test, Bass test, Y-agility Test, and Illinois Change of Direction Test. The correlation of flat feet with static and dynamic balance and physical performance in the school environment was analyzed using the non-parametric Spearman Rank statistical test. Results. The results showed significant relationships between foot grade and static balance, dynamic balance, agility, and change of direction. These relationships were indicated by correlation coefficients that showed statistical significance at p &lt; 0.05. Additionally, static and dynamic balance exhibited a negative correlation, while agility and change of direction showed a positive correlation. This suggests that higher foot grades corresponded to longer durations in static and dynamic balance tests and shorter completion times in agility and change of direction tasks. Conclusions. The findings of this study highlight the importance of investigating the relationship between flat feet, body balance, and physical performance among junior high school students. Understanding these correlations is crucial for optimizing the overall well-being and performance of adolescents.

The Effects of High-Intensity Interval Training on Cognitive and Physical Skills in Basketball and Soccer Players.

As athletes pursue excellence, training techniques continue to advance, making structured physical activity an essential tool for enhancing performance. To optimize athletic performance in modern competitive sports, the balance of physical performance and mental clarity is required. This study seeks to examine the effects of High-Intensity Interval Training (HIIT) on cognitive and physical skills in basketball and soccer players. A 3-week HIIT protocol was incorporated based on the Wingate technique. This study included 10 soccer players and 10 basketball players with an average age of 22.79 ± 1.90 years. Participants performed pre- and post-intervention assessments. Physical proficiency was assessed using 20 m sprint, change-of-direction (COD) and dribbling tests, while cognitive skills were assessed using motion object tracking (MOT), working memory, perceptual load (PL), and attention window (AW) tests. The HIIT intervention significantly improved cognitive performance in particular; noteworthy observations were a 15% improvement in motion object tracking test scores and a 16% increase in working memory test scores for basketball players. The attention window test scores showed a 32% increase, and perceptual load test scores were 31% decreased for soccer players post-intervention. There were significant improvements in physical skills; for example, sprint times were decreased by 6%, and change-of-direction and dribbling times were reduced by 8% and 7%, respectively, indicating improved agility, speed, and ball control abilities. In conclusion, both groups performed significantly better on cognitive and physical skill tests post-HIIT intervention.

Talent Identification in Football: Different Effects of Maturation on Sprinting, Change of Direction and Jumping in 13-Year-Old Players

The aim of this cross-sectional study was to assess the influence of the maturity status on speed, explosive power and change of direction (COD) in 13-year-old football players. Ninety-eight male players (age: 13.1 ± 1.0 y) were divided into late, average and early-maturation groups. Physical fitness testing included the following variables: 10 and 30 m sprint time and maximum speed in the 20–30 m segment of the 30 m sprint test, the T-test time, countermovement jump height and horizontal distance in the triple jump. The data showed a significant effect of maturity status on performance in three parameters: at maximum speed in the 20–30 m section (p = 0.024), but the only significant differences were found between the early-maturation group and average-maturation group (p = 0.033); in the COD (p = 0.024), where significant differences were confirmed between the late-maturation group and the average-maturation group (p = 0.033); and in the unilateral triple jump distance of the dominant and non-dominant (p = 0.007 and p = 0.001, respectively) lower limb. For both limbs, significant differences between the late-maturation group and average-maturation group (p = 0.005 and p = 0.013, respectively) as well as the late-maturation group and early-maturation group (p = 0.007 and p = 0.045, respectively) were shown. These results indicate that maximal speed, COD speed and unilateral lower limb reactive strength are moderated by biological age in football players aged 13 years.

A three-arm randomized controlled trial of aerobic and resistance training in women with spinal cord injuries: Effects on physical fitness and pulmonary function

BackgroundThis study aimed to investigate the effects of different volumes of aerobic training (AT) and resistance training (RT) during a concurrent exercise training program on selected indicators of physical fitness and pulmonary function in women with spinal cord injury (SCI). MethodsTwenty-three inactive females with complete or incomplete SCI from T6 to L5 were divided into three groups: concurrent training with a focus on AT (CTAT; two weekly sessions of AT and one of RT), concurrent training with a focus on RT (CTRT; two weekly sessions of RT and one of AT), and control (CON). Tests were performed before and after an 8-week experimental period for indicators of pulmonary function, aerobic power, endurance performance, muscular strength and endurance, speed, and change of direction. ResultsMarkers of both aerobic and muscular fitness increased in the CTAT and CTRT groups, but not in CON. There were significant differences in aerobic power and endurance performance between the CTAT and CTRT groups, with greater changes in CTAT. Both CTAT and CTRT improved respiratory functions, with no differences between them (p > 0.05). ConclusionsCTAT and CTRT improved most of the indicators of physical fitness. However, CTAT should be used to achieve higher aerobic power and endurance without compromising muscle strength.

Effects of a strength program on physical performance in amateur female padel players

The aim of this study was to determine the effects of an explosive strength training program on the physical performance of amateur padel players. Eight females amateur padel players, aged between 25 and 40, were randomly split up in two groups: a control group (CG, n=4) and an experimental group (EG, n=4). The experimental group performed a 6-week explosive strength training program. Physical performance variables were measured before and after the intervention using several assessments: Change of direction was gauged using a modified padel-specific test (Test 505) with the "COD Timer" application. Bilateral and unilateral horizontal jumps, along with the countermovement jump (CMJ), were measured using the "Myjump" application. Upper extremity strength was evaluated through overhead medicine ball throwing. The experimental group showed significant improvements in all analyzed variables except for the bilateral horizontal jump, dis-playing an overall enhancement in their performance following the intervention. These findings contribute to shedding light on this sport, especially within the amateur domain, as most social clubs rely on it for sustenance despite the limited available information.

Physical performance in young female football athletes: a systematic review

The objective was to analyze the physical performance in female soccer players. A systematic review was performed by searching MedLine (PubMed), SPORTDiscus, Web of Science, ScienceDirect, Scopus, Lilacs (BVS) and SciELO databases for observational studies performed on female soccer players under 18 years of age, who underwent neuromuscular and/or cardiorespiratory physical testing. Of the 934 studies found, 19 were included. The sample size in the studies ranged from 11 to 499 players, with total of 1879 athletes, aged between 9 and 17 years. Neuromuscular tests were more used than cardiorespiratory ones. In conclusion, jumps, linear velocity and change of direction were more used in the context of soccer played by women to determine performance in young athletes. However, cardiorespiratory capacity tests were used to a lesser extent, with a predominance of the level 1 yo-yo intermittent recovery test (YYIR1).

Transforming performance: The impact of an 8-week complex training program on strength, power, and change of direction in female basketball athletes.

This study aimed to investigate the effect of complex training on the strength, power, and change of direction (COD) performance of college female basketball athletes. This design used experimental and randomized studies. A total of 32 female basketball players volunteered to participate in this study and were randomly allocated to a complex training group (CT group: n = 16) and a resistance training group (RT group: n = 16). The CT group performed CT and the RT group completed RT for 8 weeks. The CT and RT programs were developed based on the linear periodization theory, which required participants to train 2 times a week in the first 4 weeks and 3 times a week in the following 4 weeks. All participants were tested using the 5-0-5 COD test, Illinois agility test (IAT), one-repetition maximum back squat (1RM BS) test, and countermovement jump (CMJ) test before and after the 8-week training period. Two-way repeated measure ANOVA showed a significant group × time interaction for the 5-0-5 COD, IAT, 1RM BS, and CMJ results after the intervention compared with that before the intervention (P < .05) in the CT group (effect size = 0.86-4.04). CT compared with RT caused remarkably larger enhancements in the IAT (P < .001) and CMJ (P = .040) scores. Our findings indicate that the implementation of CT could be a promising and innovative intervention for enhancing the strength, power, and COD performance of female basketball players.

Hazard Perception in Visually Impaired Drivers Who Use Bioptic Telescopes.

Bioptic telescopic spectacles can allow individuals with central vision impairment to obtain or maintain driving privileges. The purpose of this study was to (1) compare hazard perception ability among bioptic drivers and traditionally licensed controls, (2) assess the impact of bioptic telescopic spectacles on hazard perception in drivers with vision impairment, and (3) analyze the relationships among vision and hazard detection in bioptic drivers. Visual acuity, contrast sensitivity, and visual field were measured for each participant. All drivers completed the Driving Habits Questionnaire. Hazard perception testing was conducted using commercially available first-person video driving clips. Subjects signaled when they could first identify a traffic hazard requiring a change of speed or direction. Bioptic drivers were tested with and without their bioptic telescopes in alternating blocks. Hazard detection times for each clip were converted to z-scores, converted back to seconds using the average response time across all videos, and then compared among conditions. Twenty-one bioptic drivers and 21 normally sighted controls participated in the study. The hazard response time of bioptic drivers was improved when able to use the telescope (5.4 ± 1.4 seconds vs 6.3 ± 1.8 seconds without telescope); however, it remained significantly longer than for controls (4.0 ± 1.4 seconds). Poorer visual acuity, contrast sensitivity, and superior visual field sensitivity loss were related to longer hazard response times. Drivers with central vision loss had improved hazard response times with the use of bioptic telescopic spectacles, although their responses were still slower than normally sighted control drivers. The use of a bioptic telescope by licensed, visually impaired drivers improves their hazard detection speed on a video-based task, lending support to their use on the road.

Training Interventions for Improved Deceleration Ability in Adult Team-Based Field Sports Athletes

Background: Deceleration is a fundamental component of multidirectional speed by which athletes reduce the velocity of their centre of mass to stop or execute changes of direction following acceleration or running at a constant velocity. Enhancing deceleration abilities is crucial for athletes as successfully executing horizontal deceleration has important implications for match outcomes in sports requiring rapid multidirectional movements. However, specific training interventions targeting deceleration are scarce. The purpose of this systematic review and meta-analysis was to examine the effects of training interventions on deceleration performance in adult team-based field and court sports athletes. Methods: A systematic literature search was conducted through electronic databases, SPORTdiscus, PubMed, and Web of Science from inception to February 2022, and re-run in May 2023. The search terms were related to different training interventions and kinetic, kinematic, and performance outcomes related to deceleration performance. Studies were included if they consisted of a randomised controlled trial which investigated the effects of training on deceleration-specific outcome measures in adult team-based field and court sports athletes. Risk of bias was assessed using the revised Cochrane risk-of-bias tool for randomised trials (RoB2). Post-intervention effect sizes (Hedge’s g) were calculated between the intervention and control groups and a meta-analysis was performed using a random effects model. Results: Twelve studies were included, with 29 deceleration-specific outcomes measured in a total of 381 participants. There was inconsistency in methodological designs, including control group types, length and type of interventions and in reported deceleration-specific outcome measures. Across all observations of deceleration performance measures there was a standardised mean difference of -0.04 (95% CI: -0.50, 0.42), favouring control groups, indicating little effect of training on deceleration performance. For secondary outcomes related to deceleration, for kinetics (SMD = -0.29, 95% CI = -0.83, 0.25, I2 = 55%, p &lt; 0.01), joint kinetics (SMD = -0.20, 95% CI = -1.01, 0.61, I2 = 68%, p &lt; 0.01) and muscle activation (SMD = -0.10, 95% CI = -0.44, 0.24, I2 = 19%, p = 0.28) had greater effects for control groups, whereas joint kinematics (SMD = 0.07, 95% CI = -0.11, 0.24, I2 = 0%, p = 0.77), favoured the intervention groups. Conclusion: For the deceleration-specific outcomes reported in the included studies, training was not likely to produce a performance improvement in participants compared to control groups. However, due to methodological inconsistencies between studies and observed high risk of bias, the results should be interpreted with caution. More rigorous research methods should be included in the future to address areas that may introduce potential biases. Future research should address the differences in the type, timing, frequency, and duration of the implemented training interventions for improving deceleration performance, and in the reported deceleration-specific outcome measures. Registration: This systematic review was registered on the Open Science Framework (https://osf.io/cmwbr) (https://doi.org/10.17605/OSF.IO/CMWBR)

Dynamical reconstruction of the upper-ocean state in the central Arctic during the winter period of the MOSAiC expedition

Abstract. This paper presents a methodological tool for dynamic reconstruction of the state of the ocean, based, as an example, on observations from the Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) experiment. The data used in this study were collected in the Amundsen Basin between October 2019 and January 2020. Analysing observational data to assess tracer field and upper-ocean dynamics is highly challenging when measurement platforms drift with the ice pack due to continuous drift speed and direction changes. We have equipped the new version of the coastal branch of the global Finite-volumE sea ice–Ocean Model (FESOM-C) with a nudging method. Model nudging was carried out assuming a quasi-steady state. Overall, the model can reproduce the lateral and vertical structure of the temperature, salinity, and density fields, which allows for projecting dynamically consistent features of these fields onto a regular grid. We identify two separate depth ranges of enhanced eddy kinetic energy located around two maxima in buoyancy frequency: the depth of the upper halocline and the depth of the warm (modified) Atlantic Water. Simulations reveal a notable decrease in surface layer salinity and density in the Amundsen Basin towards the north but no significant gradient from east to west. However, we find a mixed-layer deepening from east to west, with a 0.084 m km−1 gradient at 0.6 m km−1 standard deviation, compared to a weak deepening from south to north. The model resolves several stationary eddies in the warm Atlantic Water and provides insights into the associated dynamics. The model output can be used to further analyse the thermohaline structure and related dynamics associated with mesoscale and submesoscale processes in the central Arctic, such as estimates of heat fluxes or mass transport. The developed nudging method can be utilized to incorporate observational data from a diverse set of instruments and for further analysis of data from the MOSAiC expedition.

Research on the Law of Crack Propagation in Oil Well Fracturing Process

In the field of oilfield fracturing development, a profound understanding of the evolution and propagation of damage during the fracturing process is crucial for preventing well water coning and channeling. This study aimed to unravel the complexity of damage evolution during fracturing and elucidate the causes of well water flooding phenomena. To accurately describe the damage propagation laws, a damage constitutive model considering compaction and post-peak correction parameters was established in this research. The model, through parameter adjustment, enhances the precision of stress calculation during the rock compaction phase and accounts for the stress degradation pattern subsequent to damage. This model was applied to simulate the damage evolution under various conditions in oil layer profiles and wellbore cross-sections, including the impact of different perforation angles, natural fracture patterns, and the ratio of longitudinal to transverse boundary pressures. The research concludes that well water channeling and flooding are primarily caused by damage propagation and the connectivity with adjacent water-bearing formations. The proposed rock damage constitutive model demonstrated an accuracy improvement of more than 3% compared to previous studies. Additionally, the study discovered that when the angle between the perforation section and the formation exceeds 30°, the risk of fracture propagation into adjacent layers increases, leading to an elevated risk of post-fracturing water flooding. The presence of natural fractures in the oil layer provides a conduit for damage propagation, accelerating the process of damage in the oil layer. Furthermore, the perforation angle and the ratio of boundary pressure loads during the fracturing process were identified as the main factors influencing the direction change of fracture propagation. The conclusions drawn from this study provide a scientific basis for preventing post-fracturing water channeling and flooding issues and offer new perspectives for the development of well fracturing technology, aiding in the resolution of water flooding problems associated with well fracturing.

Nonvolatile ferroelectric control of both magnetic anisotropy and half-metallicity in multiferroic heterostructures GdI2/Al2Te3

Nonvolatile all-electric spin manipulation is optimal for low-power and compact spintronic devices. Herein, using first-principles density functional theory, we propose a bilayer van der Waals (vdW) multiferroic heterostructure (HS) GdI2/Al2Te3 constructed of ferromagnetic electride GdI2 and ferroelectric (FE) semiconductor Al2Te3 to possess robust magnetoelectric coupling near room temperature. By reversing the electrical polarization states in Al2Te3, the magnetoelectric coupling not only allows the reversible switch of GdI2 from semiconductor to half-metal but also promotes the reversible transition of magnetocrystalline anisotropy from in-plane to out-of-plane. More importantly, the high Curie temperature (TC) of GdI2 and the unspoiled semiconducting nature of Al2Te3 in the HS predict the practical feasibility of this spin manipulation. Additionally, GdI2 exhibits substantial valley polarization when its magnetization direction changes to out-of-plane. These findings pave the way for achieving robust and efficient spin manipulation through all-electric control and also provide implications for multiferroic memory devices with highly efficient data reading and writing based on the HS.