Test Subjects Research Articles

Development Of Smart App Creator 3 (SAC) Learning Media In Learning History To Increase Students' Interest In Learning At Senior High School 3 Magelang

This research has: 1) the purpose of developing history learning media using the Smart App Creator 3 (SAC) application; and 2) to determine the feasibility of learning media using the Smart App Creator 3 (SAC) application. This research uses the Research and Development (R&D) method using the Analyze, Design, Development, Implementation, and Evaluate (ADDIE) model. This research was conducted at SMA Negeri 3 Magelang. The small group test subjects were 34 students, while the large group test subjects were 108 students. Data analysis used qualitative data (observation and interview) and quantitative data (questionnaire). The results of product development have produced history learning media based on the Smart App Creator 3 (SAC) application. The product was assessed by material experts and media experts with a score of 94 and 103 included in the criteria of good/worthy of use and the results of the large group trial scored 86 in high criteria so that the media is suitable for use in learning History at SMA Negeri 3 Magelang.

Appropriate Nitrogen Application for Alleviation of Soil Moisture-Driven Growth Inhibition of Okra (Abelmoschus esculentus L. (Moench))

Uneven rainfall, in the context of global warming, can cause soil moisture fluctuations (SMFs) that harm crop growth, and it is not yet known whether nitrogen (N) can mitigate the harm caused by a strong SMF. This paper uses okra as a test subject and sets three SMFs of 45–55% FC (W1), 35–65% FC (W2), and 25–75% FC (W3) and three N applications of 0 kg hm−2 (N0), 110 kg hm−2 (N1), and 330 kg hm−2 (N2) to investigate the effects of SMF and N application on the physiological and biochemical aspects of okra. The results demonstrated that okra exhibited the highest values in stem diameter, number of leaves, photosynthesis characteristics, antioxidant enzyme activity, and yield under the N1 treatment. The average yield in the N1 treatment was 149.8 g, significantly surpassing the average yields of the N0 (129.8 g) and N3 (84.0 g) treatments. Stomatal density, antioxidant enzyme activity, malondialdehyde content, and proline content in okra leaves were highest in the W3 treatment, indicating that plants experienced stress in the W3 treatment. However, the agronomic traits and yields of okra in the N1 treatment were higher than those in the N0 and N1 treatments, indicating that the crop damage caused by W3 could be mitigated by an appropriate amount of N application. The N1W1 treatment emerged as the most suitable combination for okra growth in this study, exhibiting the highest stem diameter, leaf count, photosynthetic characteristics, and yield (201.3 g). Notably, this yield was 67.8% higher than the lowest treatment (N2W3), signifying a significant improvement.

Co-ordinate-based positional embedding that captures resolution to enhance transformer’s performance in medical image analysis

Vision transformers (ViTs) have revolutionized computer vision by employing self-attention instead of convolutional neural networks and demonstrated success due to their ability to capture global dependencies and remove spatial biases of locality. In medical imaging, where input data may differ in size and resolution, existing architectures require resampling or resizing during pre-processing, leading to potential spatial resolution loss and information degradation. This study proposes a co-ordinate-based embedding that encodes the geometry of medical images, capturing physical co-ordinate and resolution information without the need for resampling or resizing. The effectiveness of the proposed embedding is demonstrated through experiments with UNETR and SwinUNETR models for infarct segmentation on MRI dataset with AxTrace and AxADC contrasts. The dataset consists of 1142 training, 133 validation and 143 test subjects. Both models with the addition of co-ordinate based positional embedding achieved substantial improvements in mean Dice score by 6.5% and 7.6%. The proposed embedding showcased a statistically significant advantage p-value< 0.0001 over alternative approaches. In conclusion, the proposed co-ordinate-based pixel-wise positional embedding method offers a promising solution for Transformer-based models in medical image analysis. It effectively leverages physical co-ordinate information to enhance performance without compromising spatial resolution and provides a foundation for future advancements in positional embedding techniques for medical applications.

Mikale Instant Porridge's Formulation and Acceptability As a Complementary Breast Milk

Background: The quality of human resources can be impacted by nutritional status. A condition known as lack of protein energy occurs when a person consumes insufficient amounts of nutrient-rich food to meet their needs. Supplementary food for breast milk that is high in energy and protein is one way to ensure that children receive a healthy diet, especially those aged 6 to 24 months.Research Purposes: This research aims to determine the formulation, acceptability, and analysis of the dietary fiber and macronutrient content (protein and carbohydrates) in MiKaLe instant porridge. Research Methods: This research method is an experimental study using a completely randomized design (CRD) that is non-factorial, with 35 panelists who are organoleptic test subjects and three formulations. Research Result: The results of the organoleptic test indicated that the chosen MiKaLe instant porridge, made with 15 grams of yellow millet flour, 25 grams of catfish flour, and 20 grams of soybean flour, was formula 1 (F1). Based on the Comstock acceptability test results, 90% of children left less than 50% of the product, and 10% left more than 75%. The product's nutritional facts state that every 100 grams has 397.99 kcal of energy, 18.52% protein, 14.55% fat, 48.24% carbs, and 16.60% dietary fiber. According to the Friedman test, there is a correlation between color, aroma, flavor, and texture. Conclusion: The results of this research indicate that instant MiKaLe porridge is suitable for breast milk substitutes for infants between the ages of six and eleven months.

Development of the P5 Module (Adipura Module) with The Entrepreneurship Theme for Elementary School Students as An Effort to Strengthen the Values of The Pancasila Student Profile

This research aims to develop the P5 Adipura Module with the theme of entrepreneurship for elementary school students as an effort to strengthen the values of the Pancasila student profile (P3). The research method used was research and development adopting Sugiyono's development model with 7 stages including potential and problems, data collection, product design, design validation, design revision, product testing, and product revision. The test subjects were students in class 4 phase B elementary school. The trial was carried out in small groups. The data collection process was in the form of interviews, observations, and distributing questionnaires. Data analysis uses quantitative and qualitative descriptives. The result of this research was a product in the form of the P5 Adipura Module on the use of family medicinal plants (TOGA) on the theme of entrepreneurship. The average result of material expert validation was 3.29 with valid criteria. Likewise, the average media expert validation result was 3.20 with valid criteria, suitable for use in the project learning process by educators and students. Experiments in small groups to show the practicality of the module can be seen from the score interval obtained from the practicality sheet instrument by users (teachers and students) of 3.86 with very practical criteria. The Adipura P5 module is suitable for use, making it easier for educators and students in the learning process.

Метод викликаних потенціалів як перспективний напрямок дослідження ноцицепції у наркотизованих тварин

The sensation of pain is a pathogenetic link in a wide range of diseases, and the study of nociception as its component is an important area of physiology and medicine. However, modern requirements for research conducted using laboratory animals require the search for new approaches to studying nociception and analgesia with minimizing the suffering of subjects in ethological testing and maximizing the transition to instrumental testing. We proposed the use of a standard formalin model of pain in combination with the recording of changes in somatosensory cortex potentials caused by electrical stimulation of efferents at the level of the forelimb. It was found that after subcutaneous injection of 0.30 ml of 4% formalin, the amplitude of evoked potentials increased. Under the conditions of the proposed testing design, both dosedependent and time-dependent effects of the formalin model of pain were observed in an anesthetized animal. The peculiarity of the obtained results was that the fixed somatosensory potentials of the brain in the S1 forelimb region showed sensitivity to the administration of a nociceptive agent in those areas of the body that topographically did not belong to the cortical representation of the forelimbs. This probably indicates the potential universality of this test approach. Thus, it was shown that evoked potentials in the forelimb representation of the primary somatosensory cortex demonstrate a clearly fixed response to painful stimulation in the formalin model of pain and can be used in studies of nociceptive and analgesic effects as a partial alternative to standard ethological testing.

Effects of different treatments on pain, functional disability, position sense and range of motion in elite bodybuilders with chronic low back pain

Back pain is one of the major global challenges and is one of the most prevalent musculoskeletal disorders occurring in 80% of people at least once in their lifetime. Therefore, the need to find appropriate treatment methods for this issue is very important. The objective is to examine the short-term and acute effects of a treatment session with dry needling, massage therapy, stretching exercises and Kinesio tape on pain, functional disability, position sense and range of motion in elite bodybuilders with non-specific chronic low back pain. The sample of this quasi-experimental study consisted of 48 bodybuilders with non-specific chronic low back pain (all male, mean age = 25.96 ± 2.18 years; mean weight = 74.45 ± 4.51 kg; mean height = 173.88 ± 3.74 cm; mean BMI = 24.60 ± 0.74 kg/m2) who randomly were placed in 4 dry needling, massage therapy, stretching exercises and Kinesio tape groups. The duration of each intervention was 30 min. The dependent variables in this study included the massage range of motion, position sense tests and visual pain scale that were taken separately from each subject in pretest, posttest (acute effect) and follow-up test (72 h after posttest; short-term effect). The results of a 4 (groups) × 3 (time) the mixed ANOVAs showed that pain in the short-term phase was significantly lower in the dry needling group than in the stretching and massage groups (P < 0.05). Also in the acute effect phase, the flexion range of motion was significantly lower in the dry needling group than in the massage group (P < 0.05). Furthermore, the two groups of stretching and massage exercises showed significantly greater range of motion (P < 0.05). Other comparisons were not significant (P > 0.05). The findings of the study showed that both massage and stretching treatment have higher acute effects, while dry needling treatment was more effective in follow up. On the other hand, these findings show that these treatment methods can have immediate and lasting positive effects in improving the performance in elite bodybuilders with non-specific chronic low back pain.

Метод викликаних потенціалів як перспективний напрямок дослідження ноцицепції у наркотизованих тварин

The sensation of pain is a pathogenetic link in a wide range of diseases, and the study of nociception as its component is an important area of physiology and medicine. However, modern requirements for research conducted using laboratory animals require the search for new approaches to studying nociception and analgesia with minimizing the suffering of subjects in ethological testing and maximizing the transition to instrumental testing. We proposed the use of a standard formalin model of pain in combination with the recording of changes in somatosensory cortex potentials caused by electrical stimulation of efferents at the level of the forelimb. It was found that after subcutaneous injection of 0.30 ml of 4% formalin, the amplitude of evoked potentials increased. Under the conditions of the proposed testing design, both dosedependent and time-dependent effects of the formalin model of pain were observed in an anesthetized animal. The peculiarity of the obtained results was that the fixed somatosensory potentials of the brain in the S1 forelimb region showed sensitivity to the administration of a nociceptive agent in those areas of the body that topographically did not belong to the cortical representation of the forelimbs. This probably indicates the potential universality of this test approach. Thus, it was shown that evoked potentials in the forelimb representation of the primary somatosensory cortex demonstrate a clearly fixed response to painful stimulation in the formalin model of pain and can be used in studies of nociceptive and analgesic effects as a partial alternative to standard ethological testing.

Transforming Bodies, Transforming Genres: A Biocapitalistic Representation of Aging in Old (2021)

M. Night Shyamalan’s Old (2021) narrates the story of a group of people who realize that the isolated beach they are taken to by the holiday resort they are staying at causes alarmingly rapid aging. The film is based on the graphic novel, Sandcastle (2010) by Pierre Oscar Lévy and Frederik Peeters. Although Sandcastle offers no explanation but several hypotheses for the accelerated aging, Old introduces a clinical trial of a pharmaceutical company, testing medicines for chronic illnesses and clarifies that the peculiarity of the beach is used to test medicines within hours instead of a lifetime. The characters, hence, are test subjects chosen because of their illnesses. This study displays how Old, through hyper-accelerated aging, transforms what is conventionally categorised as supernatural horror into body horror scrutinising the theme of aging in terms of the generic qualities of body horror. This paper is an explicit attempt to inspect, in terms of Foucauldian biopolitics, how human health is converted into commodified data; together with the relationship between capitalism and biotechnology/ medicine.

Pengembangan Multimedia Mendongeng pada Anak Usia Dini

The use of multimedia learning media can be an effective means of improving the storytelling abilities of young children. By utilizing multimedia, children are not only actively involved in the learning process, but also develop creativity, imagination and speaking skills. Focusing on the needs and characteristics of children in the early stages of development is key in the process of developing learning media. This research aims to create interactive multimedia storytelling, specifically designed to improve storytelling skills in early childhood. This research uses the Research and Development (R&amp;D) research method by applying the ADDIE (Analysis, Design, Development, Implementation, and Evaluation) model to ensure success. development process. This multimedia storytelling is not only designed to provide an interesting and interactive learning experience, but also involves young children as test subjects. The research results show that there is success in developing multimedia storytelling in Sultan Fatah Demak Kindergarten class B aged 5-6 years through the CapCut application as an effective tool in facilitating multimedia learning. Product validation by media experts confirms a high level of validity. Meanwhile, field trials at the Sultan Fatah Demak Kindergarten obtained very good results with

Correlation of Thyroid Stimulating hormone and Liver function test in Hypothyroid and Euthyroid subjects

Correlation of Thyroid Stimulating hormone and Liver function test in Hypothyroid and Euthyroid subjects

ECG signal quality in intermittent long-term dry electrode recordings with controlled motion artifacts.

Wearable long-term monitoring applications are becoming more and more popular in both the consumer and the medical market. In wearable ECG monitoring, the data quality depends on the properties of the electrodes and on how they interface with the skin. Dry electrodes do not require any action from the user. They usually do not irritate the skin, and they provide sufficiently high-quality data for ECG monitoring purposes during low-intensity user activity. We investigated prospective motion artifact-resistant dry electrode materials for wearable ECG monitoring. The tested materials were (1) porous: conductive polymer, conductive silver fabric; and (2) solid: stainless steel, silver, and platinum. ECG was acquired from test subjects in a 10-min continuous settling test and in a 48-h intermittent long-term test. In the settling test, the electrodes were stationary, whereas both stationary and controlled motion artifact tests were included in the long-term test. The signal-to-noise ratio (SNR) was used as the figure of merit to quantify the results. Skin-electrode interface impedance was measured to quantify its effect on the ECG, as well as to leverage the dry electrode ECG amplifier design. The SNR of all electrode types increased during the settling test. In the long-term test, the SNR was generally elevated further. The introduction of electrode movement reduced the SNR markedly. Solid electrodes had a higher SNR and lower skin-electrode impedance than porous electrodes. In the stationary testing, stainless steel showed the highest SNR, followed by platinum, silver, conductive polymer, and conductive fabric. In the movement testing, the order was platinum, stainless steel, silver, conductive polymer, and conductive fabric.

Enhanced control of periodontitis by an artificial intelligence-enabled multimodal-sensing toothbrush and targeted mHealth micromessages: A randomized trial.

Treatment of periodontitis, a chronic inflammatory disease driven by biofilm dysbiosis, remains challenging due to patients' poor performance and adherence to the necessary oral hygiene procedures. Novel, artificial intelligence-enabled multimodal-sensing toothbrushes (AI-MST) can guide patients' oral hygiene practices in real-time and transmit valuable data to clinicians, thus enabling effective remote monitoring and guidance. The aim of this trial was to assess the effect of such a system as an adjunct to clinical practice guideline-conform treatment. This was a single-centre, double-blind, standard-of-care controlled, randomized, parallel-group, superiority trial. Male and female adults with generalized Stage II/III periodontitis were recruited at the Shanghai Ninth People's Hospital, China. Subjects received a standard-of-care oral hygiene regimen or a technology-enabled, theory-based digital intervention consisting of an AI-MST and targeted doctor's guidance by remote micromessaging. Additionally, both groups received guideline-conform periodontal treatment. The primary outcome was the resolution of inflamed periodontal pockets (≥4 mm with bleeding on probing) at 6 months. The intention-to-treat (ITT) analysis included all subjects who received the allocated treatment and at least one follow-up. One hundred patients were randomized and treated (50 tests/controls) between 1 February and 30 November 2022. Forty-eight tests (19 females) and 47 controls (16 females) were analysed in the ITT population. At 6 months, the proportion of inflamed periodontal pockets decreased from 80.7% (95% confidence interval [CI] 76.5-84.8) to 52.3% (47.7-57.0) in the control group, and from 81.4% (77.1-85.6) to 44.4% (39.9-48.9) in the test group. The inter-group difference was 7.9% (1.6-14.6, p < .05). Test subjects achieved better levels of oral hygiene (p < .001). No significant adverse events were observed. The tested digital health intervention significantly improved the outcome of periodontal therapy by enhancing the adherence and performance of self-performed oral hygiene. The model breaks the traditional model of oral health care and has the potential to improve efficiency and reduce costs (NCT05137392).

Every "Body" Gets a Say: An Augmented Optimization Metric to Preserve Body Pose during Avatar Adaptation in Mixed/Augmented Reality.

User-Avatar interaction within augmented reality applications is rapidly increasing in frequency. Applications routinely place users in rooms with other, remote users embodied by photorealistic avatars, or require users to work with an avatar of a remote user to complete a task. During these types of interactions, it is often required to modify or redirect the posture of an avatar to achieve goals such as contact with or pointing at an object or maintaining eye gaze with the local user. A key limitation of modern redirection techniques is successfully preserving body posture, a critical component of nonverbal communication. This paper presents a new pose-preserving objective function to be used in the multi-objective optimization of an avatar's kinematic configuration. This objective function not only mimics the correct placement of body joints, but also preserves their orientation in space. We have tested this approach against several commonly used and current state-of-the-art redirection techniques and have found that our new approach achieves a significant reduction in targeted redirection error while simultaneously reducing body posture error. Additionally, human subject testing has shown that our new technique provides both a significantly more natural looking redirection and a significantly more realistic and believable overall body posture.

Experimental Evaluation of Pedestrian-Induced Multiaxial Gait Loads on Footbridges: Effects of the Structure-to-Human Interaction by Lateral Vibrating Platforms.

The introduction of resistant and lightweight materials in the construction industry has led to civil structures being vulnerable to excessive vibrations, particularly in footbridges exposed to human-induced gait loads. This interaction, known as Human-Structure Interaction (HSI), involves a complex interplay between structural vibrations and gait loads. Despite extensive research on HSI, the simultaneous effects of lateral structural vibrations with fundamental frequencies close to human gait frequency (around 1.0 Hz) and wide amplitudes (over 30.0 mm) remain inadequately understood, posing a contemporary structural challenge highlighted by incidents in iconic bridges like the Millennium Bridge in London, Solferino Bridge in Paris, and Premier Bridge in Cali, Colombia. This paper focuses on the experimental exploration of Structure-to-Human Interaction (S2HI) effects using the Human-Structure Interaction Multi-Axial Test Framework (HSI-MTF). The framework enables the simultaneous measurement of vertical and lateral loads induced by human gait on surfaces with diverse frequency ranges and wide-amplitude lateral harmonic motions. The study involved seven test subjects, evaluating gait loads on rigid and harmonic lateral surfaces with displacements ranging from 5.0 to 50.0 mm and frequency content from 0.70 to 1.30 Hz. A low-cost vision-based motion capture system with smartphones analyzed the support (Tsu) and swing (Tsw) periods of human gait. Results indicated substantial differences in Tsu and Tsw on lateral harmonic protocols, reaching up to 96.53% and 58.15%, respectively, compared to rigid surfaces. Normalized lateral loads (LL) relative to the subject's weight (W0) exhibited a linear growth proportional to lateral excitation frequency, with increased proportionality constants linked to higher vibration amplitudes. Linear regressions yielded an average R2 of 0.815. Regarding normalized vertical load (LV) with respect to W0, a consistent behavior was observed for amplitudes up to 30.0 mm, beyond which a linear increase, directly proportional to frequency, resulted in a 28.3% increment compared to rigid surfaces. Correlation analyses using Pearson linear coefficients determined relationships between structural surface vibration and pedestrian lateral motion, providing valuable insights into Structure-to-Human Interaction dynamics.

DEVELOPMENT OF AN INTEGRATED E-BOOKLET I-SETS (ISLAMIC, SCIENCE, ENVIRONMENT, TECHNOLOGY, AND SOCIETY) ENVIRONMENTAL CHANGE MATERIAL FOR CLASS X SMA/MA STUDENTS

The use of integrated I-SETS (Islamic, Science, Environment, Technology, and Society) learning media on environmental change aims to train students' creativity. This research aims to analyze the feasibility, student responses and teacher responses to the product being developed, namely the I-SETS integrated e-booklet on environmental change. The research carried out is research and development (R&amp;D), using the ADDIE development model. Data collection techniques used were interviews and questionnaires (validation, teacher and student responses). The test subjects were carried out on one teacher and 11 class XI students of SMA Negeri 1 Kotagajah. Data analysis in this research used qualitative and quantitative data. The research results indicate that the media developed has met the following criteria: (1) material expert validation of 74% with "feasible" criteria; (2) media expert validation of 86% with the criteria "very feasible"; (3) the results of the biology teacher response trial with a percentage of 96% showed that the media developed was "very suitable" for use; and (4) assessment of 11 students' response test to the product developed with a percentage of 88% with the criteria being very suitable for use as a learning resource for class environmental changes to train students' creativity.

DEVELOPMENT OF WEB-BASED INTERACTIVE LEARNING MEDIA ON THE TOPIC OF LIVING ORGANISM ADAPTATION USING THE TUTORIAL METHOD

Web-based interactive learning media is a computer-based learning media, which was developed to provide feedback on user activities. The aim of this research is to develop appropriate web-based interactive learning media, on material on the adaptation of living things, using the tutorial method. The type of research used is Research and Development with the ADDIE development model, which has stages of analysis, design, development, implementation and evaluation. The test subjects were sixth grade students at SDN Sungai Miai 11 Banjarmasin. Data collection techniques were carried out using questionnaire techniques and test techniques. The data analysis techniques used are descriptive statistics and n-gain. The result of this research is web-based interactive learning media on the adaptation of living things using the tutorial method, which was developed using HTML, CSS, Bootstrap, Javascript, JSON, Firebase, Canva and Netlify technology. The results of the analysis show that the learning media material content is valid, in the very high category, while the media validity value is in the high category. The results of the practicality test show that the media is declared practical, with student responses on average agreeing. The media is also declared effective, with an n-gain value for medium qualifications and average student learning outcomes above the KKM. Therefore, web-based interactive learning media, on the adaptation of living things, using the tutorial method is declared suitable for use as supporting media in science learning in sixth grade.

Bioelectrical activity in temporalis and masseter muscles across different gnathic types

Relevance. Discrepancies in the bioelectrical activity of the masseter muscle were observed through surface electromyography analysis. Despite the availability of scientific literature on the morphological and anatomical variances in the mastication muscles and subcutaneous adipose tissue across different gnathic types, these differences are often overlooked in the interpretation of surface electromyography absolute values.Materials and methods. A clinical evaluation, including the measurement of craniofacial parameters and an electromyography study of the right and left temporalis (RTA and LTA) and masseter muscles (RM and LM), was conducted on 73 individuals aged 21 to 24. Subjects were categorized based on upper and lower face gnathic type indices into three groups of 10: Group 1 (brachyfacial type), Group 2 (mesofacial type), and Group 3 (dolichofacial type). The study compared the surface electromyography-derived IMPACT index and average amplitude values of the muscles across groups, alongside analyzing the correlation between electromyographic values and gnathic type indices (GPDu.f./t-t and GPDl.f./ko-ko), with statistically significant differences noted at p ≤ 0.017.Results. Differences in RM and LM parameters, and the IMPACT index during the "Maximal Voluntary Gnathic Clenching of the Jaws" (MVC) test were statistically significant among the groups. An increase in both the IMPACT index and average masseter muscle values was noted in dolichofacial subjects. Significant variations in LM values during the MVC test were observed between dolichofacial and mesofacial subjects. In the MVC test, groups 1 and 3 demonstrated a moderately strong positive correlation between the IMPACT index and GPDu.f./t-t and GPDl.f./ko-ko, while a strong positive correlation was identified between the RM parameter and GPDu.f./t-t and GPDl.f./ko-ko.Conclusion. In the MVC test, the RM and LM parameters, as well as the average IMPACT index, were notably higher in dolichofacial subjects compared to other groups. A direct correlation between the mean right masseter bioelectrical activity and the average IMPACT index with the upper and lower facial gnathic indices was observed in brachyfacial and dolichofacial subjects in the MVC test.

Using Social Media and Artificial Intelligence to Find Your Purpose.

These days, the distractions of the digital world often obscure the journey to discover one's purpose. Yet these distractions hold clues to that very purpose. This article explores social media and artificial intelligence (AI) as tools to assist individuals in uncovering and expressing their purpose. As a test subject, my social media data were analyzed by AI to identify my purpose, using accounts from LinkedIn, Facebook, Instagram, and WhatsApp. This led to my creating an AI bot named Purpose GPT, which is customized to facilitate the exploration of purpose across personal growth, professional development, thought leadership, and legacy-building dimensions. Purpose GPT employs ChatGPT 4 and the Educated Change Digital Twin technology to provide a nuanced approach to understanding and discovering one's multi-dimensional purpose in this world.

METHODOLOGY FOR EXPERIMENTAL RESEARCH OF THE FIRE HAZARD OF POWER LITHIUM-ION BATTERIES OF ELECTRIC VEHICLES UNDER THE INFLUENCE OF A HEATING PANEL

Even though lithium-ion batteries (LIBs) are the subject of various tests and research at the production stage, there are no isolated cases of electric vehicle fires, and the development dynamics are unpredictable. The particular danger of such fires lies in the oxygen release during an irreversible exothermic reaction in LIBs, which creates new challenges for fire and rescue services when extinguishing such fires. The study aims to develop the main provisions of the methodology for experimental studies of electric vehicle power batteries in terms of fire hazards using an electric heating panel. The ultimate goal of the study is to determine the temperatures at which an irreversible exothermic reaction, the opening of ventilation holes, and the combustion (explosion) of electric vehicle power batteries begin, as well as the time parameters at which such processes occur. Taking into account the peculiarities of the occurrence and course of the irreversible exothermic reaction, we have developed a methodology, the essence of which is to determine the temperatures of the onset of the irreversible exothermic reaction of the electric vehicle power battery, the opening of ventilation holes, and the combustion (explosion) of electric vehicle power batteries, the combustion temperatures of ventilation gases, as well as the time parameters at which these processes occur, which may change during battery operation and not correspond to the declared parameters of the manufacturer. For this purpose, we exposed LIBs to thermal energy from an electric heating panel and recorded the temperature and time during which an irreversible exothermic reaction occurs from the moment of an internal short circuit to a fire or explosion. The use of the proposed methodology of experimental studies of the elements of power batteries of electric vehicles regarding the fire hazard of an electric heating panel will make it possible to determine the temperature limits of the occurrence of irreversible exothermic reactions in LIBs, as well as the time parameters under which these processes occur. Keywords: electric vehicle fire, irreversible exothermic reaction, lithium-ion battery.