Static Position Research Articles

Analisis Faktor Risiko Ergonomi Pada Pekerja Pembuat Jaja Sengait Di Desa Sading Mengwi Badung

The home industry that is developing in Sading village is the sengait jaja industry. This is due to the large number of requests and relatively cheap prices. Ergonomics analysis is needed to create safe, comfortable, healthy working conditions, so as to create effective work activities and can increase productivity. The method used in this research is descriptive with observation, interview, and documentation methods. The results of this study were analyzed descriptively with an ergonomic approach. The results of this study are the occurrence of repetitive movements, bad working posture, static working positions, extreme temperatures and work stress in workers who make jaja sengait. From the results of this analysis it can be suggested by (a) redesigning the work station; (b) adapting work facilities to anthropometry and types of work, so that work attitudes can be more ergonomic; (c) work environment and carrying out exercise actions in between breaks to reduce musculoskeletal disorders, fatigue and can reduce boredom at work so that productivity increases.

Predicting stability of synchronous nonlinear vibration in vertical rotating shaft system with journal bearing

Journal bearings (JBs) play a vital role in rotating machines across various fields. In vertical rotating shaft systems with JB, synchronous vibration experiences stages of destabilization and stabilization as rotational speed increases due to self-excited vibration. The onset speed of instability (OSI1) can be predicted via conventional eigenvalue analysis around static equilibrium positions. However, conventional analysis cannot determine the stabilizing and destabilizing speeds (OSS and OSI2) at which self-excited vibration disappears and reappears; numerical and experimental methods suffice. No other theory adequately explains these phenomena. This paper proposes an analytical method based on linearizing JB force and generalized eigenvalue analysis to efficiently predict synchronous vibration stability in vertical rotating shaft systems. The extended eigenvalue analysis directly determines synchronous orbit stability. Demonstrating accuracy and efficiency, a characteristic curve representing stability changes within an unbalance range is calculated, compared with numerical results. Our method serves as an input to rotor dynamic software, calculating rotating shaft-bearing stability thresholds.

ANALISIS INDIKASI RESIKO POSTUR PENGGUNA DESAIN MEJA BELAJAR PORTABEL

Study portable desks can help people easily move from one another place. Using a study portable desk would make users fix the position once a few moments so that they risk experiencing bodily discomfort. Analysis indications of posture risk can be done by selecting launch rapid upper limb assessment (RULA) analysis from the ergonomic tools toolbar in CATIA software. This research aims to identify movements that occur when using a portable study desk and to analyze user posture risks that can be experienced when using a portable study desk. Based on the research results, it is known that the body posture of portable study desk users for group A on the upper arms is in the range of 20-45°, and the lower arms are in the range of 60-100°. The wrist enters the neutral position range. The rotation of the wrist can be seen that the hand is pointing inward. It has a degree of freedom of 90° with a maximum flexion angle of 160° and a minimum extension angle of 0°. Group B body posture for the stem body has a degree of freedom of 0°. The legs experience a slight downward movement with a degree of freedom of 6.061° and a maximum flexion angle of 135°. Posture analysis results for body parts. Details of the upper arm, forearm, wrist, and wrist twist have a score of 1, which means no posture needs to be corrected and the posture is acceptable. Details of body parts, namely neck, trunk, and legs, are indicated in green, which means no posture needs to be corrected and the posture is acceptable. The score results for body parts with the static posture option get an assessment score of 2 with a green color indication, so it can be concluded that the risk indication for this posture is acceptable.

Postural education program for socially vulnerable adolescents protected by institutional care: case series

AbstractIntroduction: Institutionalized young people may exhibit impaired development due to lack of support, correct guidance regarding their physiological changes, and knowledge about postural changes. Methods: This is a longitudinal observational case series study. Adolescents residing in shelters who could understand the entire protocol were invited to participate in the study. Ten meetings were held, once a week, with 8 theoretical-practical interventions and 2 pre and post-PEP evaluations. The evaluations were: static posture, dynamic balance, handgrip strength, self-esteem, quality of life, and a theoretical questionnaire on general knowledge.Results: From 18 adolescents, 11 (7 boys and 4 girls), with an average age of 14.8 (±1.3) years concluded the study. After the PEP intervention, a significant improvement was found in the knee angles (3.56º vs. 2.28º) and hip (-12.03º vs. -4.18º) in its plane lateral. The scores of the theoretical questionnaire were 4.75 vs. 11.63 and the handgrip strength was 22.91 vs. 28.54 kgf and 21.55 vs. 26.82 kgf for the right and left limbs. In the quality of life and self-esteem questionnaires, no statistically significant differences were obtained. Conclusion: PEP imparts benefits to socially vulnerable adolescents for postural angles, handgrip strength and theoretical knowledge. Self-esteem and quality of life did not change, probably due to their high vulnerability.

Research on Indoor Fusion Positioning Based on EKF for Uwb_Imu

The study aims to improve the accuracy and stability of indoor positioning by integrating information from two types of sensors: UWB (Ultra-Wideband) and IMU (Inertial Measurement Unit) calibrated to eliminate system errors. The fusion algorithm utilizes Extended Kalman Filter (EKF) to combine UWB data and IMU measurements. First, the IMU undergoes self-calibration to correct system errors. Then, UWB ranging technology is used to estimate the target's position, and the information from the IMU's gyroscope and accelerometer is used to update the kinematic model. Finally, the EKF filters and predicts measurement errors and system noise to obtain accurate target position estimation. Experimental results demonstrate that this fusion method can enhance the precision and robustness of indoor static target positioning. The research findings are highly applicable in areas such as indoor positioning and intelligent surveillance.

Profil Atlet Tolak Peluru Cabang Olahraga Atletik

This study aims to determine the anatomical structure of the body of a shot put athlete. The research method used in this study is a quantitative approach. The sampling technique uses (purposive) or based on the purpose of not having overlapping data when conducting data analysis. The results of the research conducted showed that the condition of the shot put athlete who took part in the 2021 POPNAS selection in Central Java was said to be moderate with a BMI of 28.08 so it was said to be obese and with the results of a speed of 5.2 seconds, running 30 meters was said to be moderate, flexibility 16 cm, agility 12 seconds, up and down 59 times. . With the psychological level of athletes in the good category of shot put with an average value of 72.8%, for muscle explosive power of 3.95 it is said to be moderate. The conclusion is not only body posture but physical condition is very taken into account in this study, the physical condition of the shot put athletes who took part in the 2021 POPNAS selection in Central Java can be said to be with moderate criteria. Physical condition is very important especially for an athletic athlete in the shot put number because it is to balance a large body posture.

Approach–Avoidance Responses to Affective Facial Expressions and Bodily Posture1,2

AbstractHuman beings perceive the emotions of others through various cues, such as facial expressions, voice, and bodily posture. These social signals have been acquired evolutionarily, and reports suggest that emotions are recognized to some extent in a culturally universal pattern. It has also been suggested that an observer's approach or avoidance responses toward the expressor occur at the initial stage of emotion perception. However, such approach–avoidance reactions have hitherto been examined mainly in response to facial expressions and not bodily postures. Therefore, this study examined approach–avoidance responses to anger and fear as visualized through facial expressions and bodily postures. The study sample comprised 58 university students. The results showed that, as in a previous study, approach responses to fear and avoidance responses to anger were dominant in both facial expression and bodily posture conditions. This suggests that bodily posture and facial expression are social signals that can elicit an approach–avoidance response from the observer.

Linguistic modality acts in existential semiotics: the epistemological turn from “being-in-the-world” awareness to “lived-through-world” experience

Abstract Against the background of deliberations about the conception of worldhood as developed in existential semiotics on the basis of linguistic modality acts, this paper proposes merging mundane and transcendentalist phenomenology with epistemology as a theory of knowledge, in general, that alludes to pragmatic sources of human knowledge about the world, in particular. From the epistemological perspective, the reality of the human “life-world” is considered not only as a static position of the individual subject’s being-in-the-world, but also as his/her/its experience of living-the-world or things-of-the-world. Against the background of epistemology, defined in terms of ontological and gnoseological assessments pertaining to the knowledge of how things exist and how they are cognitively accessible, and epistemology as an activity of acquiring knowledge about an object of cognition, the author puts forward a hypothetical deductive scaffold of the linguistically and phenomenologically rooted documentary epistemology of practice, which refers to the practicing researchers’ knowledge as a set of texts created for the purposes of communicating in the first person about the awareness of lived word-ness and lived sign-ness of the transmedial and multimodal means and ways of how the world is perceived.

A novel isolation system with enhanced QZS properties for supporting multiple loads

Various quasi-zero stiffness (QZS) isolators with high-static and low-dynamic stiffness (HSLDS) play an important role in effectively attenuating vibrations within the low-frequency range. Most existing QZS isolators can effectively achieve low-frequency vibration isolation under a certain load capacity, but cannot achieve excellent isolation performance for other load capacities. Hence, in this study, a novel isolation system composed of n series-arranged rhombic QZS elements for different supporting loads is proposed to explore its benefits in achieving ultra-low frequency vibration isolation. The novelty of the present design lies in the ability to support multi-load levels while maintaining multiple enhanced QZS properties by conveniently connecting QZS rhombic elements in series. The piecewise static stiffness responses are theoretically analyzed for multiple enhanced QZS characteristics. Nonlinear restoring forces are simulated by ADAMS to verify the theoretical results, which demonstrates that the static behavior of the proposed isolation system has multiple enhanced QZS behaviors. By employing the harmonic balance method (HBM), the nonlinear dynamic equation is formulated and subsequently solved to determine the vibration transmissibility. The vibration transmissibility of the novel isolation system with multiple QZS properties under different key parameters including the supporting load or static equilibrium position, base excitation amplitude, and damping coefficient are calculated. Numerical results demonstrate that the proposed isolation system can achieve superb ultra-low frequency and even full-band vibration isolation performance with a guaranteed stable equilibrium for different loads. The presented design provides new insights into ultra-low frequency passive vibration isolation required in various engineering fields.

An MRI-based articulatory analysis of the Kannada dental-retroflex contrast

AbstractThis paper investigates the production of dental and retroflex stops, fricatives, nasals, and laterals in the Dravidian language Kannada. This is done using articulatory contours extracted from an extensive midsagittal MRI corpus of two female Kannada speakers’ static vocal tract postures intended to capture key aspects of phonemic articulations. Articulatory modelling was used to determine a set of components responsible for the implementation of place and manner contrasts (/t̪ s̪ n̪ l̪/ vs. /ʈ ʂ ɳ ɭ/). These components included both lingual and non-lingual articulatory parameters. Constriction location and length were also determined based on articulatory contours. The results showed that the two speakers produced non-fricative retroflexes with a retracted tongue tip making a constriction behind the alveolar ridge and a characteristic convex tongue shape, yet without a retraction of the posterior portion of the tongue. Apart from the lingual parameters, place differences were also manifested by the vertical position of the larynx (lower for retroflexes). The realisation of the place contrast in sibilant fricatives was different, as /ʂ/ appeared to be produced by both speakers with a laminal alveolopalatal constriction. Manner differences were captured by various non-lingual parameters, yet being also manifested in constriction locations (more anterior for stops). These findings are discussed in the context of previous descriptive and articulatory accounts of dental-retroflex contrasts.

Fronto-parietal theta high-definition transcranial alternating current stimulation may modulate working memory under postural control conditions in young healthy adults.

This study aimed to investigate the immediate effects of fronto-parietal θ HD-tACS on a dual task of working memory-postural control. In this within-subject cross-over pilot study, we assessed the effects of 20 min of 6 Hz-tACS targeting both the left dorsolateral prefrontal cortex (lDLPFC) and posterior parietal cortex (PPC) in 20 healthy adults (age: 21.6 ± 1.3 years). During each session, single- and dual-task behavioral tests (working memory single-task, static tandem standing, and a dual-task of working memory-postural control) and closed-eye resting-state EEG were assessed before and immediately after stimulation. Within the tACS group, we found a 5.3% significant decrease in working memory response time under the dual-task following tACS (t = -3.157, p = 0.005, Cohen's d = 0.742); phase synchronization analysis revealed a significant increase in the phase locking value (PLV) of θ band between F3 and P3 after tACS (p = 0.010, Cohen's d = 0.637). Correlation analyses revealed a significant correlation between increased rs-EEG θ power in the F3 and P3 channels and faster reaction time (r = -0.515, p = 0.02; r = -0.483, p = 0.031, respectively) in the dual-task working memory task after tACS. However, no differences were observed on either upright postural control performance or rs-EEG results (p-values <0.05). Fronto-parietal θ HD-tACS has the potential of being a neuromodulatory tool for improving working memory performance in dual-task situations, but its effect on the modulation of concurrently performed postural control tasks requires further investigation.

EXERGAMES AND CARDIOVASCULAR AND MOTOR ADAPTATIONS IN FEMALE ADOLESCENTES: AN INTERVENTION STUDY

Objective: to analyze the contribution of a physical conditioning program with exergames on postural control and to compare cardiovascular autonomic function among female adolescents.&#x0D; Methods: longitudinal study with overweight and non-overweight female adolescents, aged between 10 and 16 years, submitted to two assessments, when heart rate variability (HRV) and postural control were investigated during participation in the conditioning program with exergames&#x0D; Results: HRV indices for the time domain (RMSS and SDNN), showed significant differences between the pre and post moments of the program with exergames (14.67 [5.86; 22.72]; 12.38 [4, 82; 20.88]), respectively. In postural conditions BPA/AO open base with parallel feet and open eyes (0.19 [0.05; 0.32]), BTD/AO (semi-tandem base with straight forward foot and open eyes) (-0.17 [-0.32; -0.01]), BTD/OF (semi-tandem base with straight forward feet and eyes closed) (-0.21 [-0.38; -0.04]) and BTE/OF (semi-tandem base with left foot forward and eyes closed) (-0.2 [-0.38; -0.02]) differences were found between the pre and post moments of the muscle activation values of the flexor and extensor muscles of the ankle. The same adjustments were not identified for the overweight group. The total displacement of the pressure center in the BTD/AO postures (0.19 [0.02; 0.36]) in the eutrophic group (with adequate weight), and in the BTE/OF (0.77 [0.18; 1.41]) in the overweight group, in pre and post comparisons, statistically significant differences were found.&#x0D; Conclusion: exergames can contribute to physiological adaptations to cardiovascular and motor levels in adolescents.&#x0D;

Evaluating the ergonomic deficiencies in computer workstations and investigating their correlation with reported musculoskeletal disorders and visual symptoms among computer users in Bangladeshi university

BackgroundNowadays, computer users are facing musculoskeletal disorders (MSDs) and visual symptoms. Prolonged sitting in inappropriate, awkward, and static postures on the computer workstation may cause musculoskeletal disorders (MSDs). Similarly, inappropriate placement of monitors, illumination, and other factors such as prolonged usage of computers are related to visual symptoms. Objective: This study aims to evaluate the ergonomic deficiencies of computer workstations and their correlation with MSDs and visual symptoms. Methods: This study involved 271 university employees from a Bangladeshi engineering university. Ergonomic deficiencies were evaluated through direct observations and Occupational Safety and Health Administration checklists. In addition, the Nordic Musculoskeletal Questionnaire was used to assess the prevalence of MSDs and visual discomforts. Binary Logistic Regression (BLR) analysis was also used to examine the correlation between musculoskeletal symptoms and ergonomic deficiencies. Results: Results showed serious deficiencies in workstation setup, seating arrangement, monitor orientations, keyboard orientations, other input device orientations, and accessory setup. Employees reported that the MSDs in different body regions during the last 12 months including lower back (62 %), upper back (53 %), shoulders (47 %), and neck (25 %). Moreover, itchy eyes (69 %), tired eyes (83 %), and unclear vision (56.83 %) were the most common visual discomforts or visual symptoms among the participants. Results also revealed that monitor ergonomics and its orientation deficits were significantly associated with visual discomforts. Gender, job type, age, BMI, work experience, duration of computer work, and beak taking after 2 h were the independent variables reliably predicting the MSDs and visual symptoms. Conclusion: It is evident that MSDs and visual symptoms were associated with computer workstation deficiencies and other work-related factors.

Azure Kinect performance evaluation for human motion and upper limb biomechanical analysis

Human motion tracking is a valuable task for many medical applications. Marker-based optoelectronic systems are considered the gold standard in human motion tracking. However, their use is not always feasible in clinics and industrial environments. On the other hand, marker-less sensors became valuable tools, as they are inexpensive, noninvasive and easy to use. However, their accuracy can depend on many factors including sensor positioning, light conditions and body occlusions. In this study, following previous works on the feasibility of marker-less systems for human motion monitoring, we investigate the performance of the Microsoft Azure Kinect sensor in computing kinematic and dynamic measurements of static postures and dynamic movements. According to our knowledge, it is the first time that this sensor is compared with a Vicon marker-based system to assess the best camera positioning while observing the upper body part movements of people performing several tasks. Twenty-five healthy volunteers were monitored to evaluate the effects of the several testing conditions, including the Azure Kinect positions, the light conditions, and lower limbs occlusions, on the tracking accuracy of kinematic, dynamic, and motor control parameters. From the statistical analysis of the performed measurements, the camera in the frontal position was the most reliable, the lighting conditions had almost no effects on the tracking accuracy, while the lower limbs occlusion worsened the accuracy of the upper limbs. The assessment of human static postures and dynamic movements based on experimental data proves the feasibility of applying the Azure Kinect to the biomechanical monitoring of human motion in several fields.

Neck Health Metrics and Quality of Life: A Comparative Study in Bike Drivers with and without Neck Pain.

Neck pain is a prevalent musculoskeletal issue among bike drivers, often resulting from extended static postures, repetitive head movements, and exposure to vibrations. This study aims to assess the connection between cervical ROM, neck proprioception, CVA, and QOL in bike drivers with neck pain compared to those without neck pain so that the targeted interventions can be developed to enhance their well-being. A cross-sectional study involving 100 bike drivers aged 20-50 years was conducted, split into two groups: those with neck pain (n=50) and those without neck pain (n=50). Cervical ROM was measured using a smartphone, neck proprioception was assessed through a head repositioning test, and CVA was determined using lateral-view photographs with a plumb line. The Short Form-36 (SF-36) questionnaire was employed to evaluate QOL. Data analysis was conducted using independent t-tests and Pearson's correlation coefficient. Bike drivers with neck pain exhibited significantly reduced cervical ROM (p-value=<0.001), impaired neck proprioception (p-value=<0.001), and decreased CVA (p-value=<0.001) compared to their counterparts without neck pain. A strong negative correlation was found between neck pain and QOL, with lower scores in all eight domains of the SF-36. Cervical ROM, neck proprioception, and CVA showed moderate correlations with various QOL domains (p-value=<0.05). Neck pain in bike drivers is linked to decrease cervical ROM, compromised neck proprioception, and reduced CVA. These factors correlate with a lower quality of life, both physical and mental domains. Interventions addressing these aspects may enhance the quality of life for bike drivers experiencing neck pain.

Stand up to better pay attention, sit down to better subtract: a new perspective on the advantage of cognitive-motor interactions.

The Stroop task and subtraction rely on the different cognitive processes and cerebral regions, but both these cognitive functions interact with posture. The study of cognitive-motor interactions falls under the concept of sharing resources, implying that resources for processing are limited. Researchers try to understand this interaction by constructing dual task (DT) paradigms. None have investigated the Stroop and subtraction tasks in three inherently simple postures in two groups of young adults. This study aimed to test whether a given posture benefits a given cognitive function when cognitive and postural tasks are not overly demanding and are underpinned by common cerebral structures. This study presents the results of 60 healthy young adults performing a subtraction task in three postures (sitting, standing, and walking) and 57 healthy young adults performing the Stroop task in the same three postures. Our results showed that performance at the Stroop task, in terms of number of correct answers and interference, are better while standing or even walking compared to sitting while subtraction is better sitting compared to standing and walking. Moreover, static postural parameters did not vary when in DT compared to single task. This means that there was no additional cost on posture when achieving the cognitive activity simultaneously. The absence of impact of the DT on postural parameters in static postures and the changes in the gait pace when walking suggest that cognitive tasks can be achieved in various postures, without being too costly on posture.

A prototype smartphone jaw tracking application to quantitatively model tooth contact

ABSTRACT This study utilised a prototype system which consisted of a person-specific 3D printed jaw tracking harness interfacing with the maxillary and mandibular teeth and custom jaw tracking software implemented on a smartphone. The prototype achieved acceptable results. The prototype demonstrated a static position accuracy of less than 1 mm and 5°. It successfully tracked 30 cycles of a protrusive excursion, left lateral excursion, and 40 mm of jaw opening on a semi-adjustable articulator. The standard error of the tracking accuracy was reported as 0.1377 mm, 0.0449 mm, and 0.9196 mm, with corresponding values of 0.98, 1.00, and 1.00, respectively. Finally, occlusal contacts of left, right, and protrusive excursions were tracked with the prototype system and their trajectories were used to demonstrate kinematic modelling (no occlusal forces) with a biomechanical simulation tool.

Discovering individual-specific gait signatures from data-driven models of neuromechanical dynamics.

Locomotion results from the interactions of highly nonlinear neural and biomechanical dynamics. Accordingly, understanding gait dynamics across behavioral conditions and individuals based on detailed modeling of the underlying neuromechanical system has proven difficult. Here, we develop a data-driven and generative modeling approach that recapitulates the dynamical features of gait behaviors to enable more holistic and interpretable characterizations and comparisons of gait dynamics. Specifically, gait dynamics of multiple individuals are predicted by a dynamical model that defines a common, low-dimensional, latent space to compare group and individual differences. We find that highly individualized dynamics-i.e., gait signatures-for healthy older adults and stroke survivors during treadmill walking are conserved across gait speed. Gait signatures further reveal individual differences in gait dynamics, even in individuals with similar functional deficits. Moreover, components of gait signatures can be biomechanically interpreted and manipulated to reveal their relationships to observed spatiotemporal joint coordination patterns. Lastly, the gait dynamics model can predict the time evolution of joint coordination based on an initial static posture. Our gait signatures framework thus provides a generalizable, holistic method for characterizing and predicting cyclic, dynamical motor behavior that may generalize across species, pathologies, and gait perturbations.

Quantitative Electroencephalography: Cortical Responses under Different Postural Conditions

In this study, the alpha and beta spectral frequency bands and amplitudes of EEG signals recorded from 10 healthy volunteers using an experimental cap with neoprene jacketed electrodes were analysed. Background: One of the main limitations in the analysis of EEG signals during movement is the presence of artefacts due to cranial muscle contraction; the objectives of this study therefore focused on two main aspects: (1) validating a tool capable of decreasing movement artefacts, while developing a reliable method for the quantitative analysis of EEG data; (2) using this method to analyse the EEG signal recorded during a particular motor activity (bi- and monopodalic postural control). Methods: The EEG sampling frequency was 512 Hz; the signal was acquired on 16 channels with monopolar montage and the reference on Cz. The recorded signals were processed using a specifically written Matlab script and also by exploiting open-source software (Eeglab). Results: The procedure used showed excellent reliability, allowing for a significant decrease in movement artefacts even during motor tasks performed both with eyes open and with eyes closed. Conclusions: This preliminary study lays the foundation for correctly recording EEG signals as an additional source of information in the study of human movement.

How *CO spill-over affects C–C coupling on amorphous Cu for converting CO2 to multi-carbon products

Cu-based catalysts, especially oxide-derived Cu, exhibit high multi-carbon product selectivity, thus showing excellent industrialization prospects. Although the mechanism for the superiority is debatable, both experimental and calculation results indicate that the more disordered crystal structure is better for C–C coupling. Herein, we build an amorphous Cu model by making oxygen doping and disordered morphology to approach the actual condition. The oxygen atoms in the subsurface would diffuse to the surface, creating a vacancy that would break the C–C bond. Besides, only limited sites on the amorphous surface with low coordination number and stepped morphology are conducive to the occurrence of CO–CO coupling. Furthermore, we find that the spill-over effect on the amorphous Cu surface could promote the coupling of two *CO intermediates by reducing the reaction energy barrier rather than 50 % of the C–C coupling process on stationary positions. This beneficial strategy encourages the synthesis of C2+ products.