Changes In Pressure Distribution Research Articles

Analysis of Nanofluid Flow Over a Heated Circular Cylinder using the Volume of Fluid (VOF) Approach

This study employs a two‐phase Volume of Fluid (VOF) model to investigate the flow and heat transfer characteristics of Al₂O₃-water nanofluid over a heated circular cylinder at a Reynolds number of 100. Nanoparticle volume fractions (Φ) ranging from 1% to 10% were analyzed. A comprehensive grid-independence study and code validation were conducted to ensure the accuracy of the results. Increasing (Φ) from 0% to 10% led to significant changes in flow parameters: the mean drag coefficient increased by 27.8% (from 1.33 to 1.7), the fluctuating lift coefficient rose by 56.5% (from 0.23 to 0.36), and the Strouhal number increased by 6.7% (from 0.164 to 0.175). Heat transfer enhancement was observed with increasing nanoparticle concentration, as evidenced by the local Nusselt number at the front stagnation point (θ = 0°) rising by approximately 40% over the same (Φ) range. The study revealed significant changes in pressure distribution around the cylinder, with higher (Φ) values smoothing the pressure gradient and altering the separation point. Time-averaged temperature contours demonstrated more uniform thermal distributions and reduced wake sizes at higher (Φ) values, indicating improved thermal diffusion and heat transfer efficiency. The (VOF) model successfully captured complex two-phase flow dynamics, revealing asymmetric nanoparticle distributions in the wake region at higher concentrations. These findings have important applications in thermal management systems, including electronic and energy systems, potentially leading to more efficient cooling systems and heat exchangers.

An observational study of lower limb muscle imbalance assessment and gait analysis of badminton players.

The imbalance of muscle strength indicators has a negative impact on players. Lower limb muscle imbalance can cause gait abnormalities and increase the risk of muscle injury or decreased performance in significantly asymmetrical situations. This study aims to assess the lower limb muscle imbalance and gait feature between the dominant and non-dominant sides of badminton players and the associations between the two variables. The study included 15 badminton players with years of training experience. Muscle strength and gait parameters were obtained from isokinetic muscle strength testing and plantar pressure analysis systems. The symmetry index was calculated based on formulas such as plantar pressure distribution and percentage of plantar contact area. In the isokinetic muscle strength test, significant differences were found in bilateral knee flexors' average power and total work at 60°/s angular speed. The hamstring to quadriceps ratio (H/Q) range of knee joints of the dominant and non-dominant sides is 0.63-0.74at low speed, while the H/Q range is 0.81-0.88at fast speed. The H/Q of bilateral knees increases with increasing angular velocity. As the angular velocity increases, the peak torque to body weight ratio (PT/BW) of the participants' bilateral knee flexors and extensors shows a decreasing trend. The asymmetry score of H/Q at 180°/s angular speed is positively related with step time and stance time. There are varying degrees of differences in gait staging parameters, plantar pressure in each area, plantar contact area, and symmetry index between the dominant and non-dominant sides of badminton players when walking. Badminton players have weaker flexors of the knee joint, imbalanced muscle strength in flexors and extensors, decreased lower limb stability, and a risk of knee joint injury on the non-dominant side. The bending and stretching strength of the knee joint on the dominant side of the players is greater than that on the non-dominant side. The pressure in the first metatarsal region of the dominant side is higher, while that in the midfoot and heel regions is higher on the non-dominant side. badminton players have better forward foot force and heel cushioning ability. Long term badminton sports result in specialized changes in plantar pressure distribution and reduced symmetry.

Effect of slope protection using concrete waste on slope stability during rainfall

Due to climate change, higher rainfall infiltration is expected in the future and it may cause a slope failure. Simultaneously, infrastructure construction and urban redevelopment are rapidly generating large amounts of construction and demolition waste that also contributes to global climate change. To ensure the stability of the slope, it is important to find cost-effective and environmentally sustainable alternatives. Waste material such as recycled concrete aggregate (RCA) can be utilized to protect the slope. The use of RCA for slope protection is that it can be used as a material for the capillary barrier system. The objective of this paper is to investigate the characteristics of pore-water pressure distribution and slope stability with the application of RCA protection during rainfall in comparison with the original slope through numerical modeling. The SWCC for the soil and RCA materials were measured using a high-suction polymer sensor (HSPS) and Tempe cell, respectively. The volume changes of the soil were measured using 3D scanner. SEEP/W was used to conduct the seepage analyses and obtain the change of pore-water pressure distribution due to rainfall infiltration. SLOPE/W was used to evaluate the stability of the slope with different climatic conditions. The use of recycled concrete aggregate (RCA) for slope protection from rainfall infiltration has been investigated in this paper. The results showed that the safety factor of the slope increased with the addition of RCA protection. Rainfall infiltration causes a reduction in soil suction and hence reduces soil shear strength, the safety factor will also decrease since the soil will become weaker.

Role of viscoelasticity in the adhesion of mushroom-shaped pillars

The contact behaviour of mushroom-shaped pillars has been extensively studied for their superior adhesive properties, often inspired by natural attachment systems observed in insects. Typically, pillars are modeled with linear elastic materials in the literature; in reality, the soft materials used for their fabrication exhibit a rate-dependent constitutive behaviour. Additionally, conventional models focus solely on the detachment phase of the pillar, overlooking the analysis of the attachment phase. As a result, they are unable to estimate the energy loss during a complete loading-unloading cycle.
This study investigates the role of viscoelasticity in the adhesion between a mushroom-shaped pillar and a rigid flat countersurface. Interactions at the interface are assumed to be governed by van der Waals forces, and the material is modeled using a standard linear solid model. Normal push and release contact cycles are simulated
at different approaching and retracting speeds.
Results reveal that, in the presence of an interfacial defect, a monotonically increasing trend in the pull-off force with pulling speed is observed. The corresponding change in the contact pressure distribution suggests a transition from short-range to long-range adhesion, corroborating recent experimental and theoretical investigations.
Moreover, the pull-off force remains invariant to the loading history due to our assumption of a flat-flat contact interface. Conversely, in the absence of defects and under the parameters used in this study, detachment occurs after reaching the theoretical contact strength, and the corresponding pull-off force is found to be rate
independent. Notably, the hysteretic loss exhibits a peak at intermediate detachment speeds, where viscous dissipation occurs, which holds true in both the presence and absence of a defect. However, the presence of a defect shifts the region where the majority of viscous dissipation takes place.

Study of correlation between arches of foot and lower back pain in Eastern India

Background: Low back pain is one of the most common disorders of the musculoskeletal system, leading to impaired function and decreased quality of life in many patients. Foot arch alterations may lead to structural changes and/or affect its load distribution. It should be noted that even slight elevations of the foot’s medial longitudinal arch above the norm may lead to changes in load and pressure distribution. Hence, it becomes important to find the relationship between low back pain and altered foot arch indices leading to improper body balance. Aims and Objectives: The aims and objectives of the study are to find any correlation between lower back pain and an altered foot arch index in the Eastern Indian population. Materials and Methods: A total of 60 subjects aged 20–40 years with varying degrees of low back pain were selected. Low back pain scores of the subjects were found using modified oswestry low back pain disability questionnaire. Footprints in standing position using ink were taken on graph paper and the foot arch indices were calculated. Results: 54.16% of the male and 36.11% of female participants had low arched feet, 20.83% of male and 52.78% of female participants had normal arched feet, and 25% of male and 11.11% of female participants had high arched feet with varying degrees of low back pain. 77.42% of the participants with minimal disability due to low back pain were having normal arched feet, 71.43% of the participants with moderate disability due to low back pain were having low arched feet, and 100% of the participants with severe disability due to low back pain were having either high or low arched feet. Conclusion: This study showed that people having either low or high arched feet are at an increased risk of developing acute or chronic low back pain at some stage in their lives. Knowledge of this risk factor might even help people to choose appropriate occupations in the future.

Study on the Diffusion Characteristics of Polymer Grouting Materials Applied for Crack Filling in Underground Mines Based on Numerical Simulation and Experimental Methods.

Polymer grouting materials are increasingly used in the filling of mine fissures. Unlike conventional inorganic grouting materials, the self-expansion of polymers adds complexity to their diffusion process within the crack. The objective of this research was to examine how polymer grouting material spreads in cracks at ambient temperatures and pressure. The investigation involved conducting grouting tests and performing numerical fluid simulation calculations using the finite-volume method in the computational fluid dynamics software, ANSYS FLUENT 2022 R1. The fluid volume approach was employed to determine the boundary between fluid and air and to ascertain the variation patterns of density in the slurry and the fracture system. This study applied the principles of fluid mechanics to investigate the patterns of variation in the physical characteristics of polymer grouting materials, including their density, pressure, flow velocity, and movement distance, during the diffusion process. The results indicated that the density of the polymer grouting material decreased exponentially over time throughout the diffusion process. With the increase in the grouting's volume, the grout's pressure and the permeable distance of the grout increased. The slurry's pressure near the grouting hole exceeded the other points' pressure. The physical parameters of the slurry were numerically simulated by ANSYS FLUENT 2022 R1 software, and the results were compared with the experimental data. After comparing the numerical simulation results with the test data, it was clear that the numerical simulation method was superior in accurately predicting the distribution pattern of each parameter of the polymer slurry during diffusion. The grouting volume, pressure distribution, and real-time change in the position of the flow of slurry could be efficiently determined through numerical calculation and simulated grouting tests. This work can offer valuable information for designing polymer grouting materials used in underground mine fissures.

Full-scale experimental and numerical study of smoke spread and temperature distribution in a room-corridor structure building

This paper aims to study the smoke spread and temperature distribution inside a full-scale room-corridor structure building. A series of experiments and simulations with different fuel properties and fuel configurations (crib and pool fires) were carried out. There was a barrier at the top of the left end of the corridor, and the end wall was on the right side. The fire source was located in the room. The evolution of the smoke spread process, pressure distribution, and temperature distribution in rooms and corridors were obtained and analyzed. The results indicate that the barrier and the end wall hinder the smoke spread and make it to accumulate below the corridor ceiling. This causes the smoke layer height of the corridor to be lower than the top of the door, which changes the pressure distribution inside and outside the room and also affects the temperature distribution. Based on the changes of pressure distribution, some correction formulas for the gas flow rate and mass flux at the opening are proposed. Under the effect of the barrier and the end wall, the smoke temperature in the room and the corridor increases. A smoke temperature decaying model along the corridor direction is proposed. Some methods are used and compared to calculate the smoke layer height based on the vertical temperature distribution. The smoke layer height determined by the buoyancy frequency method is most consistent with the experimental observation values.

An ex vivo sequential ligament transection model of flatfoot

BackgroundThe ligaments implicated in the earliest stages of developing a progressive collapsing foot deformity are poorly understood. Commonly employed cadaveric flatfoot models are created from simultaneous transection of multiple ligaments, making it difficult to assess early changes in pressure distribution from ligaments critical for maintaining load distribution. A serial transection of ligaments may provide insight into changes in pressure distribution under the foot to identify a potential combination of ligaments that may be involved in early deformities. MethodsSpecimens were loaded using a custom designed axial and tendon loading system. Plantar pressure data for the forefoot and hindfoot were recorded before and after six sequential ligament complex transections. FindingsSectioning the plantar fascia (first) and short/long plantar ligaments (second) failed to generate appreciable differences in load distribution. Dividing the spring ligament (third) led to changes in hindfoot load distribution with a shift towards the lateral column indicative of hindfoot valgus angulation. All subsequent conditions resulted in similar patterns in hindfoot plantar load distribution. An anterior shift in the center of pressure only occurred after transection of all six ligament complexes. InterpretationLoss of the plantar fascia and short/long plantar ligaments are not critical in maintaining plantar load distribution or contact area. However, the additional loss of the spring ligament caused notable changes in hindfoot load distribution, indicating the combination of these three ligament complexes is particularly critical for preventing peritalar subluxation. Minimal changes in load distribution occurred when performing additional transections to reach a complete flatfoot deformity.

A Preliminary Study on the Effects of 4-Week Training Program with Interactive Floor Support on Plantar Pressure Distribution in Sedentary Individuals

Objective: Our purpose was to investigate on the effects of foot exercises by using interactive floor support as a modality of rehabilitation technology on plantar pressure distribution in sedentary individuals. Methods: Participants who were aged between 18-35, who agreed to participate voluntarily and had no pathology developed in the lower extremities in the past 6 months were included in this study. In order to determine the plantar pressure distribution change of all participants, the first and last evaluation was measured with Emed® Pedobarography. Balance and proprioception exercises on both lower extremities for 12 sessions (for four weeks, three sessions per week, lasts 15 minutes each) were performed with an interactive floor device. Results: A total of 15 healthy and sedentary subjects (12 female, 3 male, with a mean of 20,27±0,961 years and 21,31 ± 3,027 kg/m2 BMI) completed the four-week training protocol. Maximum force of total and hindfoot in both feet significantly decreased after 4-week training (p.05). Conclusion: Based on our results, the present study revealed that the 4-week training programme with interactive floor support for ankle joint could decrease maximum force of total and hindfoot on the bottom of the dominant and non-dominant side feet in healthy and sedentary individuals. Future investigation should be conducted to clarify the effects of long-term training programs with interactive floor support on plantar pressure distribution in patients with foot deformities.

Numerical Analysis of Tennis Serve Performance based on Aerodynamic Characteristics

Using the method of computational fluid dynamics, the influence of the spin axis angle of the tennis ball on the pressure distribution, lift coefficient and drag coefficient of the flow field around the tennis ball under three different serving styles, namely, flat stroke, topspin and sidespin, is investigated in depth. The results show that the lift coefficient of the tennis ball is significantly affected by the side spin serve, while the change of the lift coefficient is not obvious in the flat and top spin serves. In addition, for the drag coefficient, both topspin and sidespin serves had a significant effect on it, while the effect of the flat stroke was relatively small. It is worth noting that the changes in the spin axis angle did not lead to significant changes in the static pressure distribution on the surface of the tennis ball and the surrounding flow field under the three different serving styles. This finding is of great academic value and practical guidance for further understanding the hydrodynamic phenomena in tennis and for improving the serve technique.

Biomechanical Effects of Hindfoot Alignment in Supination External Rotation Malleolar Fractures: A Human Cadaveric Model.

Pressure distribution in the ankle joint is known to be dependent on various factors, including hindfoot alignment. We seek to evaluate how hindfoot alignment affects contact pressures in the ankle joint in the setting of supination external rotation (SER) type ankle fractures. SER fractures were created in 10 human cadaver lower extremity specimens, simulating progressive stages of injury: without fracture (step 0), SER fracture and intact deltoid ligament (step 1), superficial deltoid ligament disruption (step 2), and deep deltoid ligament disruption (step 3). At each step, varus and valgus alignment was simulated by displacing the calcaneal tuberosity 7 mm medial or lateral. Each limb was axially loaded following each osteotomy at a static load of 350 N. The center of force (COF), contact area (CA), and peak contact pressure (PP) under load were measured, and radiographs of the ankle mortise were taken to analyze the medial clear space (MCS) and talar tilt (TT). The COF (5.3 mm, P = .030) and the CA (-188.4 mm2, P = .015) changed in step 3 in the valgus hindfoot alignment compared to baseline parameters, indicating the importance of deep deltoid ligament integrity in maintaining normal ankle joint contact stress in the valgus hindfoot. These changes were not seen in the setting of varus alignment (COF: 2.3 mm, P = .059; CA -121 mm2, P = .133). PP were found to not change significantly in either varus or valgus (varus: -4.9 N, P = .132; valgus: -4 N, P = .464).The MCS demonstrated widening in step 3 compared to step 2 (0.7 mm, P = .020) in both varus and valgus hindfoot. The TT increased significantly in step 3 in the valgus hindfoot (2.8 degrees, P = .020) compared to step 0. SER-IV fractures with valgus hindfoot alignment showed significant changes in pressure distribution and radiographic parameters when compared to SER-IV fractures with varus hindfoot alignment. Based on this cadaver modeling study, patients with SERIV fracture with varus hindfoot alignment and complete deltoid ligament lesion may not need fracture fixation, whereas those with valgus hindfoot alignment likely need fracture fixation.

Study on dynamic characteristics of cavitation in underwater explosion with large charge

Underwater explosions (UNDEX) generate shock waves that interact with the air–water interface and structures, leading to the occurrence of rarefaction waves and inducing cavitation phenomena. In deep-water explosions, complex coupling relationships exist between shock wave propagation, bubble motion, and cavitation evolution. The shock wave initiates the formation of cavitation, and their growth and collapse are influenced by the pressure field. The collapsing bubbles generate additional shock waves and fluid motion, affecting subsequent shock wave propagation and bubble behavior. This intricate interaction significantly impacts the hydrodynamic characteristics of deep-water explosions, including pressure distribution, density, and phase changes in the surrounding fluid. In this paper, we utilize a two-fluid phase transition model to capture the evolution of cavitation in deep-water explosions. Our numerical results demonstrate that the introduction of a two-phase vapor–liquid phase change model is necessary to accurately capture scenarios involving prominent evaporation or condensation phenomena. Furthermore, we find that the cavitation produced by the same charge under different explosion depths exhibits significant differences, as does the peak value of cavitation collapse pressure. Similarly, the cavitation produced by different charge quantities under the same explosion depth varies, and the relationship between cavitation volume and charge quantity is not a simple linear increase. The research methods and results presented in this paper provide an important reference for studying the dynamic characteristics of deep-water explosions.

Measurements of the Effective Stress Coefficient for Elastic Moduli of Sandstone in Quasi-Static Regime Using Semiconductor Strain Gauges.

Numerous experimental and theoretical studies undertaken to determine the effective stress coefficient for seismic velocities in rocks stem from the importance of this geomechanical parameter both for monitoring changes in rock saturation and pore pressure distribution in connection with reservoir production, and for overpressure prediction in reservoirs and formations from seismic data. The present work pursues a task to determine, in the framework of a low-frequency laboratory study, the dependence of the elastic moduli of n-decane-saturated sandstone on the relationship between pore and confining pressures. The study was conducted on a sandstone sample with high quartz and notable clay content in a quasi-static regime when a 100 mL tank filled with n-decane was directly connected to the pore space of the sample. The measurements were carried out at a seismic frequency of 2 Hz and strains, controlled by semiconductor strain gauges, not exceeding 10-6. The study was performed using a forced-oscillation laboratory apparatus utilizing the stress-strain relationship. The dynamic elastic moduli were measured in two sets of experiments: at constant pore pressures of 0, 1, and 5 MPa and differential pressure (defined as a difference between confining and pore pressures) that varied from 3 to 19 MPa; and at a constant confining pressure of 20 MPa and pore pressure that varied from 1 to 17 MP. It was shown that the elastic moduli obtained in the measurements were in good agreement with the Gassmann moduli calculated for the range of differential pressures used in our experiments, which corresponds to the effective stress coefficient equal to unity.

Effects of Thrust Manipulation for Thoracic Spine on Plantar Pressure Distribution at Trained Men and Women: Analysis Through Baropodometry

Background: Thoracic spine thrust (TST) manipulation has been investigated for its mechanical and neurophysiological effect. However, changes in plantar pressure distribution still does not directly relate to TST manipulation in scientific literature. Objective: To compare differences in plantar pressure distribution post Thoracic spine thrust (TST) manipulation between men and women practitioners of resistance exercise. Methods: Thirty participants were selected (15 men and 15 women) that complied with the eligibility criteria. All participants were practitioners of resistance exercise and underwent evaluations in the baropodometry platform pre- and post- TST manipulation. All tests were performed in a single session to assess the plantar pressure and surface area of both feet, maximum peak pressure, and mean pressure. Results: The plantar pressure distribution showed significant difference (p<.001) in plantar surface area (cm2) between men vs. women group pre- and post-TST manipulation. However, women showed significant increase and decrease in right forefoot (p<.01) and hindfoot (p<.03) post-manual therapy, respectively. Conclusion: These finding confirm that TST manipulation improved the plantar surface area and distribution of the plantar surface area in women. Thus, it appears that TST manipulation acutely assists in the stability of women.

Research on the nonuniform contact characteristics and thermal behavior of friction pairs involving the radial conical buckling deformation in hydro-viscous drive

An equivalent model and a finite element method was established and used for simulating the change of contact state and pressure distribution of friction pairs under the axial pressure to obtain the radial nonuniform contact characteristics and temperature field of conical friction pairs during the soft-start condition. A two-dimensional temperature field calculation model was established based on the results of contact characteristics and convective heat transfer conditions, and the transient temperature field of friction pairs during soft-start was calculated by the finite difference method. Finally, the effects of the soft-start time, deformation degree, and thickness of the steel disk were studied. The results show that the temperature and contact pressure distribution of conical deformation friction pairs exhibit local high-temperature and high-pressure areas during the soft-start process. In the early stage of soft-start, the conical friction element locally contacts in its radial central area. The contact area spreads from the center to both sides as the soft start time increases, and two contact pressure peak areas are formed near the inner and outer diameters with the increase in axial pressure. The degree of axial deformation of conical steel disk has a significant impact on contact pressure. The larger the axial deformation, the pressure distribution would be more uneven. The distribution of temperature field is significantly affected by the contact pressure. It spreads from the middle to both sides, forming high-temperature regions in the pressure peak areas. Meanwhile, the temperature on the outer side of the friction element is higher than that of the inner side due to the influence of convective heat transfer. The duration of soft start also has a significant impact on the maximum temperature and maximum temperature difference. The results could provide a theoretical basis for exploring the correlation between the thermal buckling deformation and torque instability.

Evaluation of therapeutic benefits of botulinum toxin for foot dystonia associated with Parkinson's disease

BackgroundFoot dystonia occurs in patients with Parkinson's disease (PD) and leads to pain, malformation, and difficulty with walking. Botulinum toxin injections may be effective for foot dystonia, but the extent of improvement and effects on motor function are unclear. MethodsIn this study, we performed botulinum toxin injections for foot dystonia in 25 patients with PD. At 3 weeks and 3 months post-infection, we assessed changes in plantar pressure distribution utilizing the Pressure Plate system; dystonia using the Modified Ashworth Spasm score; pain using the visual analog scale (VAS) score; and lower extremity function using the Calf-raise Senior (CRS) test, Timed Up and Go (TUG) test, and gait parameters (eg, stride length, step length). ResultsWe found improved Modified Ashworth Spasm score (p < 0.01) and VAS score (p < 0.01) post-injection. CRS test score (3 weeks, p = 0.006; 3 months, p = 0.068), stride length (3 weeks, p = 0.012; 3 months, p = 0.715), and step length (3 weeks, p = 0.011; 3 months, p = 0.803) also improved. Plantar pressure distribution improved after botulinum toxin injection (metatarsal 1, 3 weeks, p = 0.031; 3 months, p = 0.144; metatarsal 2, 3 weeks, p = 0.049; 3 months, p = 0.065; metatarsal 3, 3 weeks, p = 0.002; 3 months, p = 0.017; metatarsal 4, 3 weeks, p = 0.017; 3 months, p = 0.144; medial heel, 3 weeks, p = 0.01; 3 months, p = 0.395; lateral heel, 3 weeks, p = 0.035; 3 months, p = 0.109). ConclusionBotulinum toxin injection for foot dystonia in patients with PD can reduce spasms and pain and normalize plantar pressure distribution, which improves balance and lower extremity function.

Numerical study on cavitation reduction using PressurePores technology

The requirements in marine propeller design are rising in quantity and quality in recent decades. Besides hydrodynamic performance demand, the targets in reducing propeller cavitation and its side effects need to be considered such as underwater radiated noise and pressure pulses, to ensure comfort requirements and environmental regulations. Using numerical simulation, the present paper investigates the reduction of propeller tip vortex cavitation (TVC) as well as the effects on its performance by employing PressurePores technology. This study uses the Potsdam Propeller Test Case (PPTC) model with commercial code STAR CCM+. The CFD results are compared with the test results in the cavitation tunnel to validate the reliability of numerical simulation. In addition, cavitation mitigation of the propeller is estimated and an obtained average performance degradation is only 2% for different cases, in terms of pore diameters and drilling methods (cylindrical pore and conus pore). This research also provides the changes in pressure distribution, turbulent viscosity, and vorticity around the propeller to clarify the reason for cavitation reduction together with the hydrodynamic efficiency degradation of the propeller.

A basic study on presentation of improvement effect of sound environments by use of computational simulation

The purpose of this study is to propose a method of presenting information so that architectural designers who do not specialize in architectural acoustics can easily understand the problems of the sound environment. This paper focuses on presenting the effects of the sound absorbing material using the time domain finite element method (TDFEM) as a computational simulation method. First, the sound fields of different room shapes and sound absorption boundaries are analyzed using TDFEM, and the changes between the sound fields are confirmed by room acoustic parameters at each sound receiving point. Next, visualization and auralization of those sound fields are attempted. The visualization allowed for a detailed capture of changes in sound pressure distribution due to differences in room boundary conditions. As for auralization, subjective differences in sound fields with different boundary conditions were confirmed using the paired comparison method.

Effect of orthopedic insoles on spinal deformity and walking in adolescents with idiopathic scoliosis summary.

To observe the effects of scoliosis-specific exercise therapy combined with braces and orthopedic insoles on improved spinal deformity and walking ability in adolescents with idiopathic scoliosis (AIS). From September 2019 to September 2020, 60 outpatient AIS patients were distributed into brace group (n = 30) at random and brace combined orthopedic insole group (n = 30). Both groups underwent brace dryness, and the observation group used scoliosis-specific exercise therapy combined with brace therapy, and on this basis, orthopedic insole intervention was added for 8 h per day for 2 months. At the same time, 20 adolescents of the same age with normal spinal development were recruited as a healthy group. GaitScan instruments were used to collect gait and plantar pressure measurements from study subjects. First, the gait and plantar pressure data of AIS patients and healthy groups were compared horizontally to ascertain the abnormal indicators, and then the spinal deformity and the above abnormal indicators were compared between the brace group and the brace combined orthopedic insole group. The plantar pressure center drift index (CPEI) in the AIS group was higher than that in the healthy group (F = 3.120, P < 0.05), and there were significant differences in the ratio of medial and lateral heel pressure (M/l) and total foot pressure (P < 0.05) between the AIS group and the healthy group, and no noticeable variations were found in the support phase period, walking speed, and proportion of each phase (P > 0.05). After treatment, the Cobb angle was significantly reduced in both the brace group and the brace combined with orthopedic insole group (P < 0.05), and there was no significant difference between the groups (P > 0.05). There were no significant changes in the pressure ratio of CPEI, M/l and bilateral full foot in the brace group (P > 0.05). The CPEI decreased in the brace combined with orthopedic insole group (P < 0.05), and the pressure ratio of M/l and bilateral full foot tended to 1 (P < 0.05), and was better than that in the brace group (P < 0.05). Patients with AIS may have local and worldwide asymmetric changes in plantar pressure distribution. The addition of orthopedic insoles has limited effect on improving scoliosis deformity in patients with AIS, but it can effectively improve the abnormal biomechanics of patients with AIS, so that the patient's force tends to be balanced.

On the Possibility of Detecting Pore Pressure Changes in Marine Sediments Using Bottom Seismometer Data

This paper is devoted to the detection and analysis of overpressure zones in unconsolidated seafloor sediments using an ocean-bottom seismometer. The methodological aspects of creating a system of anomalous pore pressure zone detection in marine sediments are studied. The aim of this study is to establish the requirements for a pore pressure monitoring system necessary to successfully detect overpressure zones based on seismic response, and to analyze temporal changes in pore pressure distribution. Data from a certain offshore field are used as a basis from which to construct synthetic models of overpressure distribution in marine sediments. Synthetic models are constructed using specially developed rock physics models for unconsolidated saturated media. Seismic responses are calculated for these synthetic models to represent data that otherwise would be obtained from bottom seismometers placed on the seafloor. Resultant seismic responses are studied with respect to the detection of overpressure zones. Possibilities and limitations of bottom seismometer data are discussed. Requirements for the frequency bands of bottom seismometers are formulated based on the results that are obtained.