Sudden Changes In Direction Research Articles

Biophysics of ACL injuries

Anterior Cruciate Ligament (ACL) injuries rank among the most prevalent and severe types of injuries, significantly impacting both athletes and non-athletes alike. These injuries not only result in immediate physical impairment, such as intense pain, substantial swelling, and a marked loss of mobility, but also carry long-term health consequences that can alter a person’s quality of life. Chronic pain, persistent instability, and an increased risk of developing osteoarthritis are among the lasting effects that can follow an ACL injury. An in-depth understanding of the biophysics behind ACL injuries is paramount for devising effective prevention and treatment protocols. Biophysics, which combines principles from physics with biological systems, provides crucial insights into the mechanical and structural integrity of the ACL and its susceptibility to injury under various conditions. This systematic review aims to collate and synthesize the current knowledge surrounding the biophysical mechanisms that underlie ACL injuries. The review encompasses a range of factors, including the biomechanical forces that place stress on the ligament, anatomical structures that may predispose individuals to injury, and physiological conditions that affect ligament health and resilience. Each of these factors plays a crucial role in the incidence and severity of ACL injuries. Biomechanical forces, for example, can involve sudden changes in direction or impact during physical activity, leading to excessive stress on the ACL. Anatomical factors might include variations in bone structure or ligament alignment that inherently increase the risk of injury. Additionally, physiological conditions such as muscle strength, flexibility, and overall ligament health can influence the likelihood and extent of an ACL injury. The findings of this review underscore the necessity of adopting integrated approaches in both injury prevention and rehabilitation. Such approaches must consider the multifaceted nature of ACL injuries, involving not only mechanical and anatomical aspects but also physiological and possibly even genetic factors. By emphasizing a multi-faceted understanding, interventions can be more effectively tailored to address the complex interplay of elements that contribute to ACL injuries. This holistic approach can lead to better outcomes for those at risk of or recovering from ACL injuries, enhancing the efficacy of prevention strategies and rehabilitation protocols.

Optimization of three-dimensional Tesla valve-based passive micromixer for gradient functional materials mixing

With the rapid development of three-dimensional (3D) printing technology, the field of multi-material fabrication, particularly in the production of functionally graded materials, has achieved revolutionary advancements. However, the structures of micromixers, which are central to this technology, have not been sufficiently studied. This study introduces an optimized passive micromixer design based on a 3D Tesla valve, specifically engineered for the efficient mixing of Fe3O4 particles within an epoxy resin E51 matrix. The micromixer leverages the fluid dynamics of the Tesla valve, where sudden changes in flow direction generate secondary flows that enhance mixing performance by disrupting laminar flow and inducing chaotic advection, thereby increasing the interfacial area between different material components. This process significantly improves mixing efficiency in the fabrication of gradient materials. Through theoretical analysis and computational simulations, the study identifies optimal configurations for the Tesla valve system, emphasizing mixing dynamics that enhance material gradient formation. The findings reveal that optimal mixing efficiency is achieved with a configuration comprising three Tesla valves. This optimal setup includes a 0.5-mm opening width at the turning point, an immediate transition from the turning point to the straight pipe (0 mm length), a 0.25-mm structural height for the Tesla valve, and an outlet distance of 0.25 mm from the curved pipe. Hopefully, this study can provide a robust reference for the significant potential of future applications in the realm of multi-material 3D printing, thereby fostering its substantial growth prospects.

Acute Effects of Myofascial Release on Foot Mobility and Performance in Basketball Players with Hypomobile Feet—A Randomized Controlled Trial

Hypomobility in the foot structure causes functional limitations. These functional limitations affect sportive performance negatively, especially in basketball, where dynamic movements such as jumping and sudden changes in direction are very intense. In this context, reducing hypomobility is important in terms of eliminating performance disorders caused by hypomobility. The purpose of this study was to investigate the acute effects of myofascial release on foot mobility and sportive performance in basketball players with hypomobile feet. This study was designed as randomized controlled experimental research. Twenty-four male basketball players (23.46 ± 2.81 years) participated in this study. The athletes were first subjected to foot mobility, balance and vertical jump tests. Then, the participants were divided into two groups: myofascial release (MR) and placebo myofascial release (PMR). Myofascial release (Graston technique) was applied to the MR group, and placebo myofascial release was applied to the PMR group. After application, foot mobility and performance measurements were performed again, and the results were analyzed. It was observed that there was a significant difference in right foot mobility (d = 4), left foot mobility (d = 6), vertical jump (d = 1.13) and dynamic balance (d = 1.03) parameters after application in the MR group. It was also determined that the acute effects of the intervention on foot mobility lasted for at least two hours (p < 0.001). There was no change in any parameter after application in the PMR group (p > 0.05). The results of this study show that a single session of myofascial release applied to the plantar sole temporarily increased foot mobility and improved vertical jump and dynamic balance performance in basketball players with chronic hypomobility.

Effects of soccer instruction on the executive functions and agility of children in early childhood.

Studies have shown that in open-skill sports the executive function of high-performing players is significantly higher than that of the control group. However, whether participation in soccer effectively improves executive function is unclear because previous studies lacked baseline measurements of executive function. Furthermore, agility, mostly developed in early childhood, is the most demanding component of physical fitness in open-skill sports, requiring sudden changes in body direction while running at full speed. However, no studies have examined the improvement in agility of young children participating in open-skill sports through comparison with a control group. This study aimed to clarify whether instruction in soccer, an open-skill sport, can effectively improve the executive function and agility of kindergarteners compared to a control group. In April 2020, 31 five-year-old children enrolled in kindergarten K in H prefecture in Japan were targeted as the intervention group and received soccer instruction for 12 weeks. In April 2020, a control group was established, consisting of 39 five-year-old children enrolled at the same kindergarten. Participants in both groups were measured for agility, inhibition, and working memory before and after (pre-post) soccer instruction for the intervention group. For each item, a two-way ANOVA of the group (intervention group・control group) x measurement period (pre-post) was performed, showing no significant interactions for working memory and agility. Because only the inhibition effect was significant, simple main effects were tested. Regarding inhibition, although the intervention group (M = 0.18, SD = 0.01) and the control group (M = 0.17, SD = 0.01) did not differ significantly in performance pre-intervention, the intervention group (M = 0.23, SD = 0.01) showed significantly better performance post-intervention compared to the control group (M = 0.19, SD = 0.01) (p < .01). Thus, soccer instruction improved kindergarteners' inhibition, to a level significantly higher than that of the control group. Still, no differences were found between groups regarding working memory and agility.

The frequency of injuries of Iranian male professional soccer players: a cross-sectional study.

Soccer is known to be a sport that carries a high risk of injuries due to its physical nature, involving intense contact and rapid movements like acceleration, deceleration, jumping, and sudden changes in direction. Compared to other sports, soccer is considered a contact sport with a heightened injury risk. The primary objective of this study was to assess the prevalence of sports injuries among professional soccer players. In this cross-sectional study, 56 male professional footballers participated to assess their injuries. The Pre-Competition Medical Assessment (PCMA) was utilized as the standard protocol for evaluating the athletes. The study examined variables such as injury type, player position on the field, and body mass index (BMI) in accordance with the FIFA-recommended PCMA guidelines. Student t-test was used to compare demographic characteristics injured and healthy athlete. Chi square and fisher exact tests were used to assess the association between player position, injury type and BMI classification. In this study, the mean age of the soccer players was 19.38 ± 1.30 years, with a history of participating in 3 to 60 matches. The highest incidence of injuries was recorded in the knee (48.21%) and ankle (30.36%), respectively. A significant relationship was found between the players' positions on the field and knee pain, with strikers experiencing more knee pain compared to players in other positions (p less than 0.04). However, no significant association was observed between the players' BMI and the occurrence of sports injuries (p greater than 0.05). Given the widespread occurrence of knee injuries among footballers, particularly in attacking players, proper planning and appropriate training protocols would be useful to prevent knee injuries and reduce treatment costs.

Comparative analysis of tracking and behavioral patterns between wild-type and genetically modified fruit flies using computer vision and statistical methods

Collective animal behavior occurs in groups and swarms at almost every biological scale, from single-celled organisms to the largest animals on Earth. The intriguing mysteries behind these group behaviors have attracted many scholars, and while it is known that models can reproduce qualitative features of such complex behaviors, this requires data from real animals to demonstrate, and obtaining data on the exact features of these groups is tricky. In this paper, we propose the Hidden Markov Unscented Tracker (HMUT), which combines the state prediction capability of HMM and the high-precision nonlinear processing capability of UKF. This prediction-driven tracking mechanism enables HMUT to quickly adjust tracking strategies when facing sudden changes in target motion direction or rapid changes in speed, reducing the risk of tracking loss. Videos of fruit fly swarm movement in an enclosed environment are captured using stereo cameras. For the captured fruit fly images, the thresholded AKAZE algorithm is first used to detect the positions of individual fruit flies in the images, and the motion of the fruit flies is modeled using a multidimensional hidden Markov model (HMM). Tracking is then performed using the Unscented Kalman Filter algorithm to obtain the flight trajectories of the fruit flies in two camera views. Finally, 3D reconstruction of the trajectories in both views is achieved through polar coordinate constraints, resulting in 3D motion data of the fruit flies. Additionally, the efficiency and accuracy of the proposed algorithm are evaluated by simulating fruit fly swarm movement using the Boids algorithm. Finally, based on the tracked fruit fly flight data, behavioral characteristics of the fruit flies are analyzed from two perspectives. The first is a statistical analysis of the differences between the two behaviors. The second dimension involves clustering trajectory similarity using the DTW method based on fruit fly flight trajectories, further analyzing the similarity within clusters and differences between clusters.

Acute Knee Injury Detection with Magnetic Resonance Imaging (MRI)

The anterior cruciate ligament (ACL) is a major ligament in the knee that helps to stabilize the joint and prevent excessive forward movement of the shinbone. An ACL tear is a common injury, especially among athletes who participate in sports that involve pivoting and sudden changes in direction. This paper proposes an ensemble model, which includes three deep learning models (EfficientNet-B7, ResNet-152V2, and DenseNet-201) and a genetic algorithm, to detect and classify ACL tears using knee magnetic resonance imaging (MRI). The ensemble model was trained on the KneeMRI dataset, which comprises labeled MRI images. The deep learning models can learn to identify subtle changes in ligament structure and signal intensity that are associated with ACL tears and the genetic algorithm is used to find the optimal prediction. The proposed ensemble model was evaluated using the KneeMRI dataset. The dataset was preprocessed using data augmentation techniques. Then, the ensemble model was applied to the KneeMRI dataset, evaluated, and compared with previous models. The accuracy, recall, precision, specificity, and F1 score of our proposed ensemble model were 99.68%, 98.73%, 99.52%, 99.62%, and 98.94%, respectively. Thus, our ensemble model has an unrivaled perceptive outcome and could be used to accurately identify and classify ACL tears, improving patient outcome.

Anterior Cruciate Ligament Tear Detection Based on T-Distribution Slice Attention Framework with Penalty Weight Loss Optimisation.

Anterior cruciate ligament (ACL) plays an important role in stabilising the knee joint, prevents excessive anterior translation of the tibia, and provides rotational stability. ACL injuries commonly occur as a result of rapid deceleration, sudden change in direction, or direct impact to the knee during sports activities. Although several deep learning techniques have recently been applied in the detection of ACL tears, challenges such as effective slice filtering and the nuanced relationship between varying tear grades still remain underexplored. This study used an advanced deep learning model that integrated a T-distribution-based slice attention filtering mechanism with a penalty weight loss function to improve the performance for detection of ACL tears. A T-distribution slice attention module was effectively utilised to develop a robust slice filtering system of the deep learning model. By incorporating class relationships and substituting the conventional cross-entropy loss with a penalty weight loss function, the classification accuracy of our model is markedly increased. The combination of slice filtering and penalty weight loss shows significant improvements in diagnostic performance across six different backbone networks. In particular, the VGG-Slice-Weight model provided an area score of 0.9590 under the receiver operating characteristic curve (AUC). The deep learning framework used in this study offers an effective diagnostic tool that supports better ACL injury detection in clinical diagnosis practice.

Sports Injuries in Basketball Players: A Systematic Review.

(1) Background: The objective of this systematic review was to collect relevant data in the available contemporary studies about sports injuries of basketball players and explain differences in sports injuries relative to gender, location, sport, and position on the court; (2) Methods: The papers were searched digitally using PubMed, MEDLINE, ERIC, Google Scholar, and ScienceDirect databases, from 1990 to 2024; (3) Results: The most frequent severe injuries for both genders are knee and ankle injuries and the most frequent forms of injury are ankle sprain and ligament strain. The most frequent injuries occur during running and after contact with the ball. Shooting guards sustain the highest injury rate followed by centers and point guards, while guards have the highest rate of adductor muscle injury; and (4) Conclusions: Studies indicate that ankle and knee injuries are prevalent among basketball players, with ankle sprains being particularly prevalent. Knee injuries are more common in female basketball players, including ACL injuries. Various factors contribute to injuries, including the biomechanics of jumping, landing, sudden changes in direction, and the physical demands placed on the body during the game.

Work bout handling of a search dog reduces handgrip strength and increases firefighters' risk of falls.

Firefighters work with dogs as support for their search activities for victims. Firefighters who handle dogs supposedly have higher acute muscle pain, more stumbling, and fatigue. This study aimed to verify the influence of a mantrailing dog on the firefighter's psychophysiological and muscular responses and the number of imbalances in a simulated activity of searching for people. The sample consisted of 10 canine operators characterized by mass (92.57 ± 9.66 kg), height (1.78 ± 0.06 m), age (37.8 ± 2.1 yr), and length of service (9.5 ± 4.6 yr), who performed a search activity under 2 experimental conditions (dog condition and control condition). The simulated search activity consisted of a predefined hike of 2.5 km between the beginning of a search and the place where the sham victim was hidden. Cardiometabolic variables, pain level, and muscular performance were measured pre and postactivity (time factor). The number of imbalances suffered during hiking was also quantified. ANOVA data indicated interactions (condition × time) related to handgrip strength (P < 0.05). Handgrip strength was reduced in the postsearch activity with the dog, and it increased the control when compared to the preactivity (-12.3% versus +9.2%). Also, the level of pain and discomfort in the neck, trunk, and hip regions was higher with dogs (P < 0.05). Under the dog and control conditions, there were 25 and 05 imbalances, respectively, during the hike. There were no significant differences between the experimental conditions for vertical jump performance and cardiovascular responses either with dog or control. The findings of this study highlight that a mantrailing dog with the firefighter increased the number of slips, trips, sudden changes in direction, and loss of body balance, accompanied by a reduction in handgrip strength, and increased acute pain in the neck, trunk, and hip. These findings may contribute to support strategies for mitigating injuries and optimizing the performance of canine operators in the fire department and other units cinotechnic.

Data-driven wind turbine sensor health validation

This paper presents a data-driven approach for detecting anomalies in wind turbine sensors, specifically anemometers and wind vanes, and the development of a smart alerting system. The study focuses on utilizing SCADA and reanalysis (ERA5) data for accurate anomaly detection and reducing false alarms through smart change point detection algorithms. The methodology involves modeling normal behavior, detecting change points, and comparing power curves before and after these points. For anemometer anomaly detection, a three-year SCADA dataset from an offshore wind farm and a synthetic dataset is used, employing an XGBoost model and the PELT algorithm for change point detection. Wind vane anomalies are identified using a nine month dataset from seven turbines, with synthetic alterations to simulate misalignments. Results show successful detection of sudden changes in wind speed and direction, with smart alarms assisting operators in decision-making. This research enhances wind turbine condition monitoring, improving reliability and efficiency.

Rolling active load relief technology for launch vehicle bundled with common booster core in face

The aerodynamic interference forces and moments of different windward surfaces of a launch vehicle bundled with a common booster core in the face vary considerably. The servo mechanism is laid out to maximize the control capability of the rocket at a certain angle. The dominant surface of the rocket is determined by aerodynamic interference and control capability. For the problem of large interference and asymmetry during the flight of a nominal rocket, a rolling active load relief control law based on the optimization of the spatial interference vector is proposed. The direction with the largest spatial interference vector is obtained online by visual acceleration information. By adjusting the rolling program angle, the rocket will align the dominant face with the direction of the largest interference when flying through the windy area. And then, the rocket obtains a good control effect. The simulation results show that the control law proposed in this paper can effectively improve the adaptability of the rocket control in the case of sudden changes in wind direction. It achieves the purpose of reducing the static load of the rocket body structure during the flight.

Failure investigation of an elbow pipe used in sewage water treatment facility

AbstractIn this research work, a real case of failed ASTM A860 WPHY 65 long elbow pipe coated with inorganic zinc ethyl silicate primer is collected from a treatment facility to investigate the root causes of its failure, which was reported after approximately 28 months of use. The failure was investigated using visual observations, metallurgical analysis using optical emission spectroscopy, mechanical testing, X‐ray diffraction of corrosion product, chemical analysis of sewage and corrosion rate test of the elbow using a three‐electrode potential technique, fractographic analysis using scanning electron microscope along with computational analysis to confirm the results. Through the testing, it was observed that severe depletion in the strength can be attributed to erosion–corrosion caused by various impurities present in the sewage, leading to the generation of corrosion pits and turbulent eddies and stresses generated due to sudden changes in fluid flow direction along with gases present in sewage reacting with a base metal. Various failure mechanisms that have led to pipe failure are discussed in this paper, along with a listing of preventive measures to delay it.

Squid as a Model Organism - Part 3: Ocular Morphology and its Implications in Biomimicry for Human Ophthalmology

The distinctive feature of cephalopods is their lack of scales, possession of eight arms and two long tentacles, with considerable diversity in shape, size, and habitat. Giant and colossal squids represent some of the largest marine creatures. Giant squids, in particular, are exceptionally captivating beings with unique characteristics that allow them to thrive in the incredibly dark depths of the oceans. Despite their large size, these cephalopods are agile swimmers, capable of sudden changes in direction. Vision is the primary sense for cephalopods, enabling them to perform these rapid movements. The giant squid (Architeuthis) has the largest eyes among marine and terrestrial animals, constituting a significant percentage of its weight and volume. These large eyes have captured the attention of biologists, leading to investigations into the anatomy, physiology, and histology of the cephalopod eye. It is noteworthy that the highest concentration of neural cells in the brain is found in the optic lobes of the giant squid, emphasizing the importance of vision in its life in dark and formidable habitats. In this review, we delve into the evolution, histology, structure, and physiology of the giant squid’s vision, followed by a comparative analysis with human optics.

Thermodynamic bifurcation in anoxic heart: A far-from-equilibrium dissipative structure.

Thermodynamic consequences of a three-hour long anoxia were investigated on the isolated mammalian rat myocardium. The anoxic heart operated in a far-from-equilibrium manner as attested by the non-linearity between the thermodynamic force and the thermodynamic flow. When subjected to slight fluctuations due to anoxia, the open far-from-equilibrium cardiac system presented a thermodynamic bifurcation at ~ 60 minutes of anoxia. The bifurcation was characterized by a sudden change of direction in the bifurcation diagram of a one-dimensional nonlinear differential equation with one parameter and occurred at a non-hyperbolic fixed point at which moment the heart lost its thermodynamic stability. The parameter of the differential equation was the single force of the myosin molecular motor. These results helped to reflect a self-organized process and the occurrence of a dissipative structure. This offers valuable insights into our understanding of myocardial protection and could be of considerable interest, especially for heart transplants where the recipient must benefit from the donor's heart in the shortest possible time.

Pickleball- and Paddleball-Related Injuries in the Lower Extremity: Description, Treatment Options, and Return to Play.

Background Pickleball and paddleball are the fastest-growing sports in the United States. However, there are limited studies on the types of lower extremity injuries and treatment options in an outpatient clinic setting. Hypothesis/purpose This study reports the incidence rate, treatments, and return-to-play (RTP) outcomes for patients presenting to a single orthopedic outpatient center with pickleball- and paddleball-related lower extremity injuries. Study design This study is a retrospective case series, with level IV evidence. Methods A database search of our multispecialty electronic medical record (EMR) system from 2015 to 2023 identified 166 patients with outpatient pickleball- and paddleball-related lower extremity injuries. The retrospective data were reviewed for patient demographics, injury type, mechanism of injury,surgical or non-surgical treatment, and return-to-play recommendations. Results We observed that the majority of the patients with pickleball- and paddleball-related injuries in the lower extremities were over 60 years of age, with more males. Additionally, most injuries encountered were ankle sprain/strain from a twisting mechanism, which was treated non-surgically.Additionally, a significant number of patients suffered an Achilles tendon rupture (12.0%), which was treated surgically with an Achilles tendon repair (88.1%), accounting for the most common surgical treatment performed in this study. Of the 166 patients who were seen and treated, 68 (40.9%) returned to play, and 93 (56.3%) were lost to follow-up. Conclusion Most of these injuries were seen in the older population and caused by a sprain or strain due to sudden changes in direction, which were treated non-surgically. The most common surgical treatment was an Achilles tendon repair due to an Achilles tendon rupture. Although a relatively good number of patients were cleared to return to play, some patients were lost to follow-up. Meanwhile, some patients were advised to stop playing pickleball or paddleball due to the severity of their injuries. As this sport continues to rise in popularity and with the incidence rate of lower extremity injuries increasing over time, orthopedic surgeons should be aware of the types of injuries, treatment options, and outcomes, as well as ways to advise patients on prevention. Therefore, further research on the standard treatments and outcomes of pickleball- and paddleball-related injuries in the lower extremities is encouraged.

Simulation and experimental study on the aerodynamic characteristics of a high-speed elevator with three-sided arc fairings

To address the crucial issue of optimizing the design of fairings for drag and noise reduction, this study focuses on a high-speed elevator in operation as the research subject. The numerical and experimental analysis investigates the influence mechanism of a three-sided arc fairing on the surface pressure distribution, surrounding airflow velocity, and aerodynamic drag of elevator cars. The results indicate that the fairing is effective in reducing the high-pressure area on the top of the car. It also helps to prevent vibrations caused by early separation of the boundary layer and periodic vortex separation, and mitigates the impact of aerodynamic forces on the car when there is a sudden change in airflow direction. As the arc radius of the fairing increases, the airflow velocity between the car and the shaft decreases. This leads to a reduction in the tail vortex area at the bottom of the car, resulting in decreased aerodynamic drag. Among the four schemes, scheme D with the largest arc radius of the fairing demonstrates the best optimization performance. Compared to the case without fairing, the car surface pressure decreases by approximately 35%. The aerodynamic drag is reduced to 129.51 N, which corresponds to a 60.13% decrease. However, the fairing has little impact on the lateral lift. The airflow velocity variations in the numerical simulation and experimental tests exhibit the same trend. The average relative error is about 10%, verifying the effectiveness of the numerical calculation method.

Geodesic equations for guided wave helical path separation for a pipe bend

The sections of pipe bends are susceptible to wall thinning by flow-accelerated corrosion due to the sudden change in the fluid flow direction and velocity. Compared to existing screening approaches, Guided Wave Tomography (GWT) has been demonstrated to provide more accurate information about the defect. In GWT an inversion problem is solved, in which a forward model is used to predict a synthetic dataset for a given physical model. Two-dimensional (2D) forward models are preferred for the inversion scheme due to the feasibility of combining these with tomographic algorithms. Since 2D models resemble the GW propagation of a plate, they do not consider the cyclic nature of the pipe. To overcome this limitation, a robust helical path separation was introduced in Huthwaite and Seher (2015) for a straight pipe. However, it relies on time-reversing the measured wave field ϕ(t) as a function of the propagation distance xs,r from the source to the receiver. Although ray-tracing and grid-based methods are capable of computing the distance xs,r for complex geometries such as the pipe bend, they are complex and time-consuming. Hence, in this paper a straight forward approach is proposed to compute xs,r based on the pipe geometry and the geodesic equations of a torus. Then the computed distance xs,r is used for removing the helical path trajectories. Compared to the distance obtained by using the Hilbert envelope, the results show that the geodesic distances preserve the information of the wavefront of interest, including the focusing effect and the scattered wave field from a Hann-shaped defect. The technique is applied to experimental data and demonstrated to separate the wavefront of interest.

Doppler Sodar Measured Winds and Sea Breeze Intrusions over Gadanki (13.5° N, 79.2° E), India

Doppler sodar measurements were made at the tropical Indian station, i.e., Gadanki (13.5° N, 79. 2° E). According to wind climatologies, the wind pattern changes from month to month. In July and August, the predominant wind direction during the monsoon season was the southwest. In September, it was the northwest and south. While the winds in November came from the northeast, they came from the northwest and southwest in October. The winds in December were out of the southeast. The diurnal cycle of winds at 60-m above the ground was visible, with disturbed wind directions in September and October. This may be connected to the Indian subcontinent’s southeastern monsoon recession. To better understand the monsoon circulation on a monthly basis, the present work is innovative in that it uses high-resolution winds measured using the Doppler sodar at the atmospheric boundary layer. The convergence of a sea breeze and the background wind might result in a sudden change in wind direction, and forecasting such a chaotic atmospheric event is crucial in the aviation sector. As a result, the wind shear that is produced may pose a serious threat to airplanes that are landing. In the current study, we present a few cases of sea breeze intrusions. The physics underlying these intrusions may help modelers better understand these chaotic wind structures and use them as inputs in their models. Based on surface-based atmospheric characteristics, there have been two reports of deep sea breeze intrusions that we report in this research. The sea breeze days were marked by substantial (moderate) drops in temperature (dewpoint temperatures) and increased wind speed and relative humidity. The India Meteorological Department (IMD) rainfall data showed a rise in precipitation over this location on 23 July (4.8 mm) and 24 July (9.5 mm) when sea breeze intrusions over Gadanki were noticed. Sea breeze intrusions could have brought precipitation (intrusion-laden precipitation) to this area due to conducive meteorological conditions. A simple schematic model is proposed through a diagrammatic illustration that explains how a sea breeze triggers precipitation over adjacent locations to the seacoast. The skew-T log-P diagrams have been drawn using the balloon-borne radiosonde measured atmospheric data over Chennai (a nearby location to Gadanki) to examine the thermodynamic parameters to gain insights into the underlying mechanisms and meteorological conditions during sea breeze intrusion events. It is found that the convective available potential energy (CAPE), which is presented as a thermos diagram, was associated with large values on 23 July and 24 July (898 J/kg and 1250 J/kg), which could have triggered thunderstorms over Chennai.

Numerical and Machine-Aided Experimental Models for Simulating the 3D Compliance of a Toothbrush

One of the most discussed topics in toothbrush design is identifying the contact force exerted by the bristles on the teeth. Each bristle must generate a contact force to ensure tooth cleaning without damaging it. Numerical simulation is a very powerful tool for understanding the influence of design parameters (bristle shape and materials). This paper proposes a flexible multibody model to efficiently simulate the 3D compliance of a toothbrush. Each bristle is modeled using a discrete, flexible approach. The contact between the bristles and the target surface is established using the penalty contact method. An experimental test bench with a Universal Robot and a flat, transparent surface is set up. Validation is provided by comparing the reaction forces of the toothbrush with the reaction forces acquired by the load cells mounted on the end effector of the Robot. The results demonstrate the accuracy of estimating normal and tangential forces in various operating situations. The discrete flexible multibody technique has also demonstrated its viability in evaluating the displacement of the bristles when the toothbrush’s base body is put through a specified motion, even when it is exposed to a sudden change in direction. As a result, the model can be effectively utilized to assess how well various brush classes remove dental plaque. Therefore, the suggested model could provide guidance for holistic modeling and advancements in toothbrush design to boost their effectiveness for thorough cleaning.