Journal of Mechanical Engineering, Automation and Control Systems
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Evaluation and design of a bite force measuring load cell
Get PDFThe measurement of bite force can be essential for assessing oral health and the functioning of the stomatognathic system. However, its use in dental offices is limited due to operational complexities and costs. This study focused on evaluating the mechanical strength of the user-friendly and low manufacturing cost load cell under development within LABBIO – Bioengineering Laboratory at UFMG, the gnathodynamometer, tailored for children. 3D modeling in SolidWorks and Finite Element Method (FEM) structural analysis were employed to ensure its ability to withstand the desired 1000 N load. Initially, the device did not meet the desired load, resulting in iterations to modify its geometry. After iterations including the replacement of the initial material with a more suitable alternative, removal of edges, and other adjustments, a final prototype meeting mechanical strength and functionality requirements was developed
Exploring the impacts of daytime sleepiness on gait, physical balance, and the occurrence of orofacial trauma: a narrative review
Get PDFDaytime sleepiness (DS) often accompanies obstructive sleep apnea (OSA), exacerbating its effects. DS can impair cognitive function, attention, reaction time, and motor coordination, increasing the risk of accidents. This study aimed to explore the relationship between DS, changes in gait and balance, and the occurrence of orofacial fractures. A narrative review was conducted using PubMed, Scopus, and Web of Science publications. The analysis revealed the impact of DS and OSA on gait and balance control in older individuals, emphasizing the need for interventions to address these issues and identify associated pathologies. Continuous Positive Airway Pressure (CPAP) therapy was recognized as a potential treatment, although further research is needed to understand DS triggers and treatment options in older populations. The study underscores the importance of analyzing interactions between the central nervous system, medications, balance, and mobility to prevent falls and related injuries. While the literature highlights the vulnerability of elderly individuals and those with OSA to falls, no established link between DS, gait, balance, and orofacial trauma necessitating medical and dental intervention was found. Thus, further research is warranted to address this gap and promote better understanding and management of these conditions
Dynamic pupillometry system
Get PDFThe phenomena of miosis (constriction) and mydriasis (dilation) of the pupil are exhibited in response to varying levels of light intensity cast upon the eye. In general, the size and responsiveness of the human pupil are under the regulatory purview of the nervous system. Consequently, the study of the pupil offers a means to discern potential abnormalities in the human organism, as it permits an assessment of the nervous system’s behavior. However, the comprehension of pupillary dynamics remains incomplete in certain facets, and methodologies for enhancing diagnostic precision continue to evolve, primarily contingent upon current technological equipment advancements. Thus, the imperative lies in the advancement of technologies that meet these research needs, as the scrutiny of pupillary responses holds the capability to detect anomalies within the human body. Hence, the objective of this endeavor is to conduct preliminary trials of a dynamic pupillometry system, designed to both stimulate and capture images of human pupils, facilitating an investigation into their behavioral patterns. The findings elucidate various pupillary parameters and reveal significant alterations in pupillary conduct, thereby contributing to the advancement of research and technologies within the realm of pupillometry. Thus, this study undertakes an innovative exploration into pupillometry, particularly regarding stimuli of varying wavelengths, thereby providing improvements on the diagnostic, prognostic and preventive capacity with heightened reliability, given the pupil’s size and its reactions cannot be manipulated or falsified since they are involuntary
Prevalence of child malocclusion and its association with time of breastfeeding and/or deleterial habits in children from 2 to 6 years old at public schools in Bento Gonçalves, Rio Grande do Sul, Brazil – pilot project
Get PDFKnowing that the worldwide prevalence of malocclusion in early childhood is 54 %, we carried out a pilot project in the first half of 2022 at Public Schools in Bento Gonçalves RS, evaluating 1938 children between 2 and 6 years old. The prevalence of malocclusion found was 23 %. Anterior open bite, whether or not accompanied by posterior crossbite, was the most prevalent malocclusion. About 70 % of the children were not breastfed or breastfed for less than 6 months, presenting a non-nutritive sucking habit. Assessing 5 years old children alone, this prevalence rose to 54 %. The results reinforce the need of public health policies that promote and support prolonged breastfeeding, which expand the knowledge of parents or guardians and school staff about the adverse effects caused by the use of pacifiers and baby bottles, with the adoption of transdisciplinary measures for the prevention, interception and treatment of malocclusions in a timely manner
Editor’s Letter. Malocclusion treatment tools evolution – electromagnetic synergism. What is the current status of knowledge? Part I
Get PDF1D manipulator with vibration impact drive, based on which it is possible to create orthogonal manipulators and robots of any dimension
Get PDFManipulator of the investigated type may move according to a straight line. It has an advantage in the fact that by choosing geometrical parameters of the manipulator it is possible to achieve its effective operation. This is presented by using analytical and graphical methods. The performed research shows that manipulators with vibration impact drives have some positive qualities. In their structure it is not necessary to include the self-stopping mechanism. In the conservative case of the system static position of equilibrium of the impact pair can be with negative, zero or positive tightening. In the case of zero tightening eigenfrequency and period of the system does not depend on the quantity of motion of impact excitation. In the case of harmonic forced excitation resonant motions take place in the vicinity of the eigenfrequency of the conservative system with zero tightening. Analytical – numerical calculations contribute to the creation of manipulators and robots with vibration impact drives
Object localization of channel robot using laser triangulation
Get PDFTrajectory tracking and Object Localization in robots are developing rapidly, but the tasks are becoming increasingly complex and significantly increasing the range of tasks for robotic systems. Cognitive tasks in domestic, industrial or traffic conditions require not only the recognition of objects but also their evaluation by classifying them without direct recognition. One of such spheres are tunnels that are physically difficult for humans to reach and require diagnostics. In such an environment, it is difficult to globally define the direction and goal, so it is necessary to interpret the locally obtained information. To solve such a problem, sensor fusion is widely applied, but sensors of different physical natures do not allow to obtain the necessary information directly, so there is a great need to use AI to interpret and control the received information and generate the robot's trajectory [1]. Local navigation systems require a wide range of sensors [4]. Various cameras and time-of-flight LiDAR lasers are widely used. For the aforementioned reasons, an economical local trajectory generation and tracking system is being developed, one of the most important components for object recognition is the laser triangulation method. The essence of this method is that the camera reacts to the projection of the laser light in front of it and interprets the obstacle depending on its distortion. In this way, the camera's resources are more concentrated, and at the same time, a simple RGB camera is enough for this method. Also, this method is perfect in the dark, when the laser light is more pronounced. In this paper, the laser triangulation method will be reviewed in detail, evaluating its advantages and disadvantages
Processing piano audio: research on an automatic transcription model for sound signals
Get PDFAutomatic transcription of sound signals can convert audio to musical notes, which has significant research value. This paper extracted dual-channel constant Q transform (CQT) spectra from piano audio as features. In the design of the automatic transcription model, a CNN was employed to extract local features and then combined with a Transformer model to obtain global features. A CNN-Transformer automatic transcription model was established using a two-layer CNN and three-layer Transformers. Experiments were conducted on the MAPS and MAESTRO datasets. The results showed that dual-channel CQT outperformed short-time Fourier transform (STFT) and mono CQT in auto-transcription. Dual-channel CQT achieved the best results on frame-level transcription for the MAPS dataset, with a P value of 0.9115, an R value of 0.8055, and an F1 value of 0.8551. A sliding window with seven frames yielded the best transcription results. Compared with the deep neural network and CNN models, the CNN-Transformer model demonstrated superior performance, achieving an F1 value of 0.8551 and 0.9042 at the frame level for MAPS and MAESTRO datasets, respectively. These findings confirm the designed model's reliability for automatic piano audio transcription and highlight its practical applicability
Design of treatment scheme and identification method of treatment effect for soft soil subgrade
Get PDFAccording to the characteristics of the soft soil subgrade in the Haiou Island section of Nansha Bridge, a comprehensive geological survey and soil analysis were conducted. Based on the analysis results, a corresponding design scheme for the soft soil subgrade was formulated to ensure bridge safety and stability. Furthermore, various reinforcement measures such as compaction, drainage, and lightweight soil were implemented to mitigate the impact of soft soil filling on the bridge structure. To evaluate the effectiveness of our treatment method, post-construction effect testing was performed using both static pressure and vibration acceleration methods. The static pressure method provided crucial parameters related to bearing capacity and compressibility of the soft soil subgrade while vibration acceleration analysis reflected response characteristics under dynamic load conditions. By comparing and analyzing results obtained from these two methods comprehensively evaluated feasibility of our treatment approach. Finally, based on experimental study findings and data analysis outcomes, it is recommended that post-construction effect testing for Haiou Island section's soft soil subgrade should employ both static pressure method and vibration acceleration method along with targeted reinforcement measures selected specifically to minimize adverse impacts on bridge structure
Analysis and optimization of vibrating screen structure based on modal simulation
Get PDFIn order to enhance the stability and reliability of the vibrating screen, modal and harmonic response characteristics were simulated and analyzed using the finite element method. The final assembly model was established in Creo, serving as an intermediate format for material definition and mesh accuracy verification. The analysis of natural frequency and mode revealed that the overall structural stiffness was basically satisfactory. However, harmonic response analysis indicated issues related to excessive stress and stress concentration within the structure. Subsequent optimization of the frame structure confirmed nearly unchanged low-order natural frequencies, while maximum stress was reduced by 22.15 %, holding significant implications for process cost control