Changes In Position Research Articles

Effects of different hinge positions on tibial rotation in uniplanar medial opening wedge high tibial osteotomy with three-dimensional tibial models

BackgroundTo investigate the effects of different hinge positions in the sagittal and axial planes on distal tibial rotation (DTR) during medial opening wedge high tibial osteotomy (MOWHTO) with three-dimensional tibial models.MethodsPreoperative CT data from 30 knee joints in 30 patients who underwent surgery for varus malalignment of knee were included. 1 standard hinge position (0°), 6 axial planes (±5°, ±10°, ±15°), and 6 sagittal planes (±5°, ±10°, ±15°) hinge positions were defined and virtual uniplanar osteotomy was performed. The correction angle of each model was generated using Fujisawa's point. Participants’ baseline characteristics, radiologic parameters and DTR were measured. One-Way Repeated Measures ANOVA and single factor linear regression analysis were used to analyze the association between tibial rotation and hinge position in the sagittal and axial planes.ResultsWe found a clear linear correlation between changes in hinge position in the sagittal plane and DTR. The changes in DTR were the smallest when the hinge position was at 5°, where internal or external rotation of the DTR may occur. When the front aspect of hinge axis rotated distally, DTR tended towards internal. Meanwhile, when the front aspect of hinge axis rotated proximally, DTR tended towards external. There were no correlations with every hinge axis position in the axial plane.ConclusionsIt is sagittal but not axial hinge axis affects DTR in uniplanar MOWHTO with three-dimensional tibial models. In the sagittal plane, every change in hinge position was significantly linearly correlated with DTR. However, no linear correlations were observed between every hinge position change in the axial plane.

A Self-Compensating Non-Intrusive Ring-Type AC Voltage Sensor Based on Capacitive Coupling

In order to reduce the influence of coupling capacitance variations on cable voltage measurement, this paper proposes a self-compensating non-intrusive ring-type AC voltage sensor based on capacitive coupling. A theoretical model of the sensor was established, and the influence of parasitic capacitance changes on sensor output was analyzed. Furthermore, a theoretical analysis shows that the parasitic capacitance between the external cable and the sensing probe, as well as between the ground and the sensing probe, will significantly affect the sensitivity of the sensor and increases the measurement error. A ring-type inductive probe and a signal processing circuit were designed, incorporating a reference signal to compensate for the influence of coupling capacitance variations. Additionally, to minimize the impact of parasitic capacitance on sensor output, the length of the outer ring electrode was extended, and a PTFE housing was designed for protection. A prototype of the sensor was developed and tested. This prototype has a good linear response to AC voltage in the measurement range of 0–1000 V with a linearity of 0.86%. The effects of changes in cable diameter and cable position on the measurement were tested separately. The worst-case error of the sensor output is less than 6.44%, representing a reduction of 21.4% compared to the uncompensated case. Under external cable interference, the sensor exhibited an output error of less than 1.85%. The results show that the designed sensor can accurately measure cable voltage despite changes in cable diameter or installation position, and also demonstrates effective shielding against external interference.

Social ageing and higher-order interactions: social selectiveness can enhance older individuals' capacity to transmit knowledge.

In long-lived organisms, experience can accumulate with age, such that older individuals may act as repositories of ecological and social knowledge. Such knowledge is often beneficial and can spread via social transmission, leading to the expectation that ageing individuals will remain socially well-integrated. However, social ageing involves multiple processes that modulate the relationship between age and social connectivity in complex ways. We developed a generative model to explore how social ageing may drive changes in social network position and shape older individuals' capacity to transmit knowledge to others. We further employ novel hypernetwork analyses that capture higher-order interactions (i.e. involving ≥ 3 participants) to reveal potential relationships between age and sociality that conventional dyadic networks may overlook. We find that older individuals in our simulations effectively facilitate transmission across a range of scenarios, especially when transmission resembles a complex contagion or when social selectivity (i.e. prioritization of key relationships) rapidly emerges with age. These patterns result from the formation of tight-knit sets of older associates that co-occur in multiple groups, thereby reinforcing one another's capacity to transmit knowledge. Our findings suggest key avenues for future empirical work and illustrate the use of hypernetworks in advancing the study of social behaviour.This article is part of the discussion meeting issue 'Understanding age and society using natural populations'.

Hyperspectral Imaging Reveals Differential Carotenoid and Chlorophyll Temporal Dynamics and Spatial Patterns in Scots Pine Under Water Stress.

Drought-related die-off events have been observed throughout Europe in Scots pine (Pinus sylvestris L.). Such events are exacerbated by carbon starvation that is, an imbalance of photosynthetic productivity and resource usage. Recent evidence suggests that optically measurable photosynthetic pigments such as chlorophylls and carotenoids respond to water stress (WS). However, there is a lack of measurements using imaging spectroscopy, and the mechanisms linking xanthophyll-related changes in reflectance captured by the photochemical reflectance index (PRI) and chlorophyll changes in red edge position (REP) to WS are not understood. To probe this, we conducted a greenhouse experiment where 3-year-old Pinus sylvestris saplings were subjected to water limitation and followed using hyperspectral imaging (HSI) spectroscopy, water status and photosynthetic measurements. Carotenoids (e.g., xanthophyll cycle) and chlorophylls responded to WS, which was observed using the HSI-derived indices PRI and REP respectively. The spatial-temporal response in these two pigment-reflectance groupings differed. The spatial distribution of PRI represented the light intensity around the time of the measurement, whereas REP reflected the daily averaged light intensity over the experimental course. A further difference was noted upon rewatering, where the carotenoid-related PRI partially recovered but the chlorophyll-related REP did not.

Dysautonomia and Postural Orthostatic Tachycardia Syndrome: A Critical Analysis of Dysautonomia: How to Diagnose and Treat.

A significant number of physicians are unclear of the vast clinical manifestations of dysautonomia and imbalance of the autonomic nervous system, specifically the parasympathetic and sympathetic nervous systems. The major obstacle has been an inability to determine the mechanism of action as well as multisystem dysfunction and a lack of clear-cut testing. Dysautonomia, a pathophysiological malfunction of the sympathetic and parasympathetic nerves in our bodies, can present as altered clinical functions of heart rate (tachycardia/bradycardia), altered breathing patterns, blood pressure (hypertension/hypotension), sweating, digestion, syncope, etc. These symptoms have caused specialists to miss this diagnosis because of relative nonspecificity. Our current analysis of patients demonstrates significant delays in diagnosis, misdiagnosis, and the development of chronic syndromes because of the above. We demonstrate that monitoring of heart rate and blood pressure with changes in position and respiration can be easily and quickly performed without orthostatic stress and can demonstrate the entities of sympathetic withdrawal, cholinergic excessive aspects as well as tachycardia, blood pressure dips with posture, etc. This analysis takes less than an hour without the need for injections or medication, thus more quickly informing the cardiologist/neurologist of the correct diagnosis. We will attempt to demystify these issues so that clinicians and the scientific community will have a better understanding of this entity and consider a diagnosis of dysautonomia earlier in the differential diagnostic process and start treatment approaches sooner.

Resolving the Controversy Surrounding the Function of the Corrugator Supercilii Muscle.

The corrugator supercilii muscle (CSM) has traditionally been recognized as a primary depressor of the eyebrows, playing a key role in expressing negative emotions and contributing to the formation of glabellar lines. However, recent studies indicate that the CSM may exhibit movements contrary to those previously documented, suggesting a more complex functional role. This research re-evaluates the anatomical and functional roles of the CSM and discusses their implications for botulinum toxin treatments. A prospective, intrapersonal comparative, and split-face study was conducted over a five-year period, from January 6, 2019, to January 6, 2024, involving 298 patients who underwent botulinum toxin injections. The study divided participants into seven groups, each targeting specific anatomical areas of the CSM and associated muscles. Injection techniques were varied to assess their impact on brow dynamics, with outcomes measured by changes in eyebrow position and expression lines. The study demonstrated that targeting specific portions of the CSM and depressor supercilii muscle (DSM) leads to distinct outcomes in brow elevation and the reduction of expression lines. However, this approach was also frequently associated with the development of omega-shaped wrinkles. Split-face evaluations further validated that the modified injection techniques achieved superior eyebrow elevation compared to traditional methods. This study challenges the traditional view of the CSM as primarily a brow depressor, highlighting its role in medial brow elevation. These findings underscore the need for a nuanced approach in esthetic medicine, particularly in botulinum toxin injections, to achieve balanced and natural facial expressions. Understanding the full range of CSM functions is crucial for optimizing esthetic outcomes and enhancing patient satisfaction. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

Performance evaluation of an automatically controlled transcutaneous energy transfer system powering left ventricular assist device.

The survival rate of LVAD recipients may be improved by eliminating the infection failure mode at the percutaneous lead entry site. Wireless powering through a Transcutaneous Energy Transfer System (TETS) is a promising solution for achieving this. However, automatic controls need to be employed to compensate for the variations in efficiency and power transfer due to changes in load and coil-to-coil gaps. This article discusses the results of invitro and animal models performance evaluation of an automatically controlled TETS for powering a Left Ventricular Assist Device. It was found that power up to 20 W could be transferred at an axial gap of 30 mm. A 5% variation in speed and a 2% change in flow rate are observed with the change in tissue thickness, in porcine carcass model. The LVAD could be operated at the required RPM irrespective of the change in axial positions.

Dramatic changes in mitochondrial subcellular location and morphology accompany activation of the CO2 concentrating mechanism

Dynamic changes in intracellular ultrastructure can be critical for the ability of organisms to acclimate to environmental conditions. Microalgae, which are responsible for ~50% of global photosynthesis, compartmentalize their Ribulose 1,5 Bisphosphate Carboxylase/Oxygenase (Rubisco) into a specialized structure known as the pyrenoid when the cells experience limiting CO2 conditions; this compartmentalization is a component of the CO2 Concentrating Mechanism (CCM), which facilitates photosynthetic CO2 fixation as environmental levels of inorganic carbon (Ci) decline. Changes in the spatial distribution of mitochondria in green algae have also been observed under CO2 limitation, although a role for this reorganization in CCM function remains unclear. We used the green microalga Chlamydomonas reinhardtii to monitor changes in mitochondrial position and ultrastructure as cells transition between high CO2 and Low/Very Low CO2 (LC/VLC). Upon transferring cells to VLC, the mitochondria move from a central to a peripheral cell location and orient in parallel tubular arrays that extend along the cell's apico-basal axis. We show that these ultrastructural changes correlate with CCM induction and are regulated by the CCM master regulator CIA5. The apico-basal orientation of the mitochondrial membranes, but not the movement of the mitochondrion to the cell periphery, is dependent on microtubules and the MIRO1 protein, with the latter involved in membrane-microtubule interactions. Furthermore, blocking mitochondrial respiration in VLC-acclimated cells reduces the affinity of the cells for Ci. Overall, our results suggest that mitochondrial repositioning functions in integrating cellular architecture and energetics with CCM activities and invite further exploration of how intracellular architecture can impact fitness under dynamic environmental conditions.

California carbon allowance futures

Carbon pricing is an important tool to address climate challenge, while limited attention has been given to the U.S. carbon derivatives market, i.e., California carbon allowance (CCA) futures market. To deal with various data frequencies, we use a mixed frequency vector autoregressive model. We find that changes in trading positions of hedgers and speculators can affect the CCA futures returns. Like other commodity futures markets, commercials act as contrarians, while non-commercials behave like momentum traders. We find some evidence of a feedback relationship between the CCA futures market and California's economic condition. The interaction between the energy sector and the carbon futures market is evident. The CCA futures market is more sensitive to climate policy risk than abnormal temperature. Other ETSs’ carbon futures prices and inflation expectation could affect the CCA futures returns on some trading days.

Dynamic shunt flow alterations through patent foramen ovale during off-pump coronary artery bypass grafting induced by airway pressure changes: a case report.

Interatrial right-to-left shunt flow through a patent foramen ovale (PFO) can be caused by changes in heart position for anastomosis during off-pump coronary artery bypass (OPCAB). We herein present a case in which the direction of PFO shunt flow changed with heart position during OPCAB and the ventilation settings after sternal closure. A 66-year-old man with interstitial pneumonia underwent OPCAB. Preoperative transesophageal echocardiography revealed right-to-left shunt flow through a PFO induced by the Valsalva maneuver. During OPCAB, heart displacement resulted in right-to-left shunting and acute hypoxemia, which quickly improved with increase of inspired oxygen fraction. After chest closure, bidirectional shunt flow developed under increased airway pressure. Vigilant intraoperative monitoring with TEE and postoperative airway pressure management are important to address shunt flow and hypoxemia due to PFO.

Elasto-inertial focusing and rotating characteristics of ellipsoidal particles in a square channel flow of Oldroyd-B viscoelastic fluids

The elasto-inertial focusing and rotating characteristics of spheroids in a square channel flow of Oldroyd-B viscoelastic fluids are studied by the direct forcing/fictitious domain method. The rotational behaviours, changes in the equilibrium positions and travel distances are explored to analyse the mechanisms of spheroid migration in viscoelastic fluids. Within the present simulated parameters (1 ≤ Re ≤ 100, 0 ≤ Wi ≤ 2, 0.4 ≤ α ≤3), the results show that there are four kinds of equilibrium positions and six (five) kinds of rotational behaviours for the elasto-inertial migration of prolate (oblate) spheroids. We are the first to identify a new rotational mode for the migration of prolate spheroids. Only when the particles are initially located at a corner and wall bisector, some special initial orientations of the spheroids have an impact on the final equilibrium position and rotational mode. In other general initial positions, the initial orientation of the spheroid has a negligible effect. A higher Weissenberg number means the faster the particles migrate to the equilibrium position. The spheroid gradually changes from the corner (CO), channel centreline (CC), diagonal line (DL) and cross-section midline (CSM) equilibrium positions as the elastic number decreases, depending on the aspect ratio, initial orientation and rotational behaviour of the particles and the elastic number of the fluid. When the elastic number is less than the critical value, the types of rotational modes of the spheroids are reduced. By controlling the elastic number near the critical value, spheroids with different aspect ratios can be efficiently separated.

Changes in Diaphragm Intrusion and Thoracic Dimensions After Posterior Spinal Fusion in Patients With Neuromuscular Scoliosis.

Cerebral palsy (CP) can cause scoliosis with large thoracolumbar or lumbar curves. Such curves may impair pulmonary function by causing the abdomen and diaphragm to encroach on the thorax. Our purpose was to investigate changes in diaphragm position and other thoracic radiographic measurements at 2 years after posterior spinal fusion (PSF). Retrospective review of data from 56 pediatric patients (Gross Motor Function Classification System >3) who underwent PSF for CP-related (neuromuscular) scoliosis at one US academic hospital from 2010 to 2018. In this study, we used radiographs taken preoperatively and 2 years after PSF to measure lung volume, diaphragm intrusion index (DII), diaphragm vertebral level (DVL), space available for the lung (SAL), and T1-S1 height. Lung volume had increased by a mean 902cm3 (range, -735 to 2697cm3) at 2-year follow-up. DII improved from a mean (and SD) of 61%±12% to 71%±11% on the left side and 58%±14% to 68%±11% on the right (P<0.001). DVL increased caudally by a mean 1.2 vertebral levels bilaterally, with a mean postoperative position between T8 and T9. Lung space became more symmetrical as the SAL increased from 0.76 to 0.91 (P<0.001). T1-S1 height increased by a mean 7.5±4.3cm. These findings suggest a new way to understand changes in thoracic volume and redistribution of thoracic and lumbar balance when correcting the collapsing spinal deformity in CP. A more caudal postoperative diaphragm position with less diaphragm intrusion into the thorax may reflect an improved length-tension configuration, which could in turn produce greater diaphragmatic strength and endurance. Level III.

Island change framework defines dominant modes of atoll island dynamics in response to environmental change

Climatic change threatens the persistence of atoll islands and the cultural and ecosystem services they support. However, adaptation and ecosystem management are constrained by lack of knowledge of island-specific transformations. We present an empirically-based island change framework that characterises the physical trajectory of islands, based on high-resolution shoreline analysis on 509 atoll islands in the central Pacific over the past half-century. Using changes in island size and position we identify seven distinct styles of island transformation in the Pacific, including contraction (21.4%), stability (46.1%) and expansion (32.4%), and show that 40% of islands are currently mobile on reef surfaces. Results challenge the framing of islands as erosional, which misrepresents island behaviour and constrains understanding of island futures. The island change framework highlights a broader set of island-specific management considerations, and opportunities, that scale with the style and rate of island change, and provides an empirical basis to inform management.

Small changes in the transducer position cause a systematic change in cardiac output readings: implications for clinical practice.

To systematically evaluate the effect of small changes in transducer position on key hemodynamic variables including CO generated by 4th generation FloTrac software. After cardiac surgery, cardiac output, mean arterial pressure, systemic vascular resistance, and stroke volume variation were measured with 4 generation Flotrac software. The transducer position was randomly placed at the midaxillary plane, 4cm higher than the midaxillary plane or 4cm lower than the midaxillary plane. Averages of three measurements were used. Data was available from 20 patients. Cardiac output increased from 4.59L/min (± 0.92) to 4.78L/min (± 0.99) with the transducer position at the midaxillary plane to 4cm higher than the midaxillary plane, and cardiac output decreased to 4.43L/min (± 0.90) with the transducer 4cm lower than midaxillary plane (P < 0.001). On the relative scale, CO increased 4.1% (95% CI 3.1-5.0) when comparing the higher transducer level with the midaxillary plane position, and CO decreased 3.4% (95% CI 2.4-4.4) when comparing the midaxillary plane position with the lower transducer level, correspondiong to changes in CO of ≈ 1% per 1cm change in transducer position. Mean arterial pressure and systemic vascular resistance both changed significantly with transducer position (both P < 0.001), whereas no statistically or clinically significant effect was seen on stroke volume variation (P = 0.98). A four-centimeter change in vertical transducer position induced clinically significant changes in cardiac output measurements by 4th generation FloTrac software. Definitions of optimal cardiac output in goal-directed therapy algorithms require meticulous transducer adjustment and can only be used in the reference patient position.

Effects of Anthropic Structures on Morphodynamic Beach Evolution along the Gulf of Roses (Northwestern Mediterranean, Spain)

This study conducts a morphodynamic analysis of beaches located in the northern sector of the Gulf of Roses (NW Mediterranean, Spain). The primary objective is to investigate mid-short (2004–2020) term spatial and temporal variations in shoreline position and sedimentological behaviour. The study area covers the northern part of the gulf, spanning 9.86 km, and includes both natural beaches and heavily anthropized ones. The following GIS methodologies were employed to study the variations in the coastline: QGIS for areas and DSAS-ArcGIS for transects, quantifying coastal changes from 2004 to 2020. Sediment samples were collected from both the dry beach and swash areas for each profile. The results reveal minor discrepancies in shoreline evolution data, depending on the method used (transects or areas). Profile-based analysis shows an average annual rate of −0.11 m·y−1 (ranging between 0.53 and −0.55 m·y−1), while areal-based results (2004–2020) indicate a total loss of −20,810 m2 (−1300 m2·y−1). Sediment grain size decreases northward (from 745 to 264 µm in the swash zone). Changes in shoreline position and grain size illustrate the impact of various anthropogenic structures on morphodynamic behaviour. These structures preferentially deposit specific grain sizes and impede sediment transport, which will cause an advance in the position of the shoreline and sediment grain sizes upstream and a reverse process downstream. This study underscores the influence of coastal anthropization on beach morphology and sedimentology, generating distinct morphodynamic behaviour.

Structural Analysis Technique and Its Validation for Large Range Mirror Refocusing System for Spaceborne Deployable Telescopes

Large aperture deployable telescopes with numerous onboard instruments are popular in the space industry for astronomy. Scientific data in various wavelength bands, from 0.6µ to 28µ, is provided by these instruments and is crucial for deep space exploration. The deployment mechanisms handle the alignment and functionality at the telescope level only. At instrument level, there is always a need for a refocusing system which can cater individual need of instrument for focusing independent to other instruments nearby. In this paper, we present a structural analysis technique for such a type of large range mirror refocusing mechanism, similar to the Near Infrared Spectrograph (NIRSpec) payload of the James Webb Space Telescope (JWST). The method relies on geometric non-linearity for large deflection, in which the structure's stiffness matrix changes as a function of loading. We have designed, analyzed structurally, and tested a 4mm range slider crank based compliant mechanism. The outcomes of linear and non-linear static analysis, computed numerically, have been compared. There are noticeable significant variations in one direction between the two analyses' results. The results are validated using appropriately designed and realized test setups, like measurements of displacement, changes in focus and image position of the optical system.

Serological and molecular characterization of novel ABO variants including an interesting B(A) subgroup.

ABO grouping is the most important pretransfusion testing that is directly related to the safety of blood transfusion. A weak ABO subgroup is one of the important causes of an ABO grouping discrepancy. Here, we investigated the characterization of four novel ABO variants including a novel B(A) subgroup. RBCs were phenotyped by standard serology methods. The full coding regions of the ABO gene and the erythroid cell-specific regulatory elements in intron one were sequenced. The effect of the possible splice site variant was predicted by Alamut software. The 3D structural modeling of three relative B(A) enzymes (p.Met214Thr, p.Met214Val, and p.Met214Leu) were performed by PyMOL software. Four novel ABO alleles were identified with weak ABO expression in this study, in which two would lead to premature terminations, and two resulted in amino acid changes. In silico analysis revealed that the splice site variant c.155G>T had the potential to alter splice transcripts. 3D structural view shown that the variant amino acid position 214 was spatially adjacent to the donor recognition pocket residues (266Met and 268Ala) and just next to the 211DVD213 motif. The size of the side chain of Thr and Val is the smallest, Leu is medium, and Met is the largest, and the size changes in the critical position 214 may affect the donor recognition pocket. Four ABO subgroup alleles were newly linked to different kinds of ABO variants and the possible mechanism through which they produce weak ABO subgroups was analyzed in silico.

High accuracy of component positioning and restoration of lower limb alignment using robotic medial unicompartmental knee arthroplasty.

Unicondylar arthroplasty was performed using robotic medial unicompartmental knee arthroplasty (R-mUKA) and gap-balancing instrumentation. Our hypothesis was that robotic unicondylar knee arthroplasty accurately restores component positioning and lower limb alignment when compared to preoperative planning with actual implantation throughout the range of knee motion due to proper knee balancing. Data were collected prospectively and were analysed for patients undergoing RM-UKA. A cemented UKA was implanted using the MAKO® robotic system. Lower limb alignment at 0°, 30°, 45°, 60° and 90° of flexion was recorded of the native knee, with the trial components in place and finally after component implantation. A spacer according to the femorotibial gap was introduced and the alignment was measured. The position of the final component was planned based on three-dimensional computed tomography images before making the bone cuts. The positioning of the femoral and tibial components was analysed in all three planes. A total of 52 patients were included (mean age 66.3 ± 6.7 years; 34 males, 18 females). The difference in femoral component position after planning and final implantation was 0.04° ± 0.58° more valgus in the coronal plane (p = 0.326) and 0.6° ± 1.4° more flexion relative to the sagittal plane (p = 0.034). The tibial component was placed in the coronal plane in 0.3° ± 0.8° of more varus (p = 0.113) and in the sagittal plane in 0.6° ± 1.2° of more posterior tibial slope (p = 0.001). Lower limb alignment of the native knee in extension was 5.8° ± 2.6° of varus and changed to 3° ± 2.1° varus after UKA (p ≤ 0.01). R-mUKA helps to achieve the target of alignment and component position without any significant differences to the planning. Ligament balancing causes non-significant changes in component position. It allows optimal component position even for off-the-shelf implants respecting the patient's specific anatomy. II.

Laboratory and numerical investigations on land-sourced solute transport in coastal fractured aquifers

Land-based pollutants threaten coastal aquifers, highlighting the need to protect groundwater and nearshore marine ecosystems. While aquifer heterogeneity has been recognized as a significant factor affecting solute behavior, the impact of fractures on land-sourced solute transport in coastal aquifers remains unclear. This study attempted to address this issue through laboratory experiments and discrete fracture matrix (DFM) models. The impact of horizontal fractures on the temporal and spatial characteristics of solute transport, spreading, and discharge under seawater intrusion was analyzed based on variations in fracture position and length. The results show that fractures/low-velocity zones (LVZ) can accelerate/delay solutes, dividing them into different transport modes and enhancing/prolonging their spreading/discharge duration. Changes in fracture position and length also affect its transport acceleration and path deviation abilities, which ultimately determine when solute discharge occurs. The mixing zone and unsaturated zone, in addition to the LVZ, hinder solute transport, reducing the rate and delaying the end of solute discharge. Meanwhile, fractures facilitate solute transport into the saltwater wedge, expanding the solute discharge zone. However, if solutes are initially within the LVZ, their entry into the fracture rely on their distance from the fracture's near-land edge and the size of the fracture's convergence zone.

Simulating 2D Fluid Motion with the Smooth Particle Hydrodynamic Approach

Abstract Virtual two-dimensional (2D) fluid simulation is useful for directly simulating fluids in various situations, including geological simulations for landslides and fluid simulations for teaching. This research aims to simulate the behaviour of three different types of fluids (water, coconut oil, and glycerine) in a 2D container and analyse how these three types of fluids behave under various conditions, including interactions with boundaries. The research used Python programming to simulate fluids and the Wondershare Filmora X application to combine images. The Smooth Particle Hydrodynamics method simulated fluid in a 2D container with 10,000 particles by deriving the force density field directly from the Navier-Stokes equations. The Navier-Stokes equations were utilized to find the acceleration and velocity of fluid particles by considering external forces, internal forces, and gravity through this method. Acceleration and velocity were validated due to wall collisions, collisions with boundaries, and collisions between particles, which caused changes in particle position and velocity. During visualization, the fluid velocity decreased over time due to attenuation caused by interactions between neighbour particles, particles with boundaries, and particles with walls. From the simulation, it was observed that the fluid flowed from a higher place to a lower place, with fluid particles taking the shape of the container and the surface of the fluid forming waves. On the other hand, simulations with boundaries indicated that smaller gap sizes and higher viscosities led to increased difficulty in fluid penetration into the gap within the container.