Acoustic quality assessment in a classroom through simulations and measurements

The acoustic quality in a classroom directly impacts the educational relationship between the student and the teacher, reducing speech intelligibility. In addition, inadequate acoustic comfort burdens the vocal health of teachers. This study evaluated a classroom at the Federal University of Paraná, Campus Centro Politécnico, to verify its acoustic quality. The measurements of the acoustics descriptors: Reverberation Time (RT), Definition (D50), Central Time (Ts), Early Decay Time (EDT) were performed according to the ISO 3382-2 standard, concerning Noise Curves (NC) and Background Noise (BGN) these were evaluated by the NBR 10152 and S12.2 standards. The Speech Transmission Index (STI) was measured according to IEC 60268-16 and evaluated according to ISO 9921. The useful-detrimental ratio (U50) and the other descriptors were simulated in the ODEON software version 11. Thus, the results showed that the evaluated room did not meet the minimum requirements in terms of acoustic quality, for the descriptors RT, STI, Ts, D50, RF, and NC. Simultaneously, the RT and STI were also outside the limits established by the German and Finnish standards. Therefore, it is concluded that the evaluated classroom did not reach the minimum acoustic quality requirements.

Subjective perceptions of students and teachers to environmental noise in public schools

Formal education takes place in the classroom, where learning involves intensive verbal communication between teachers and students. Therefore, classrooms must offer the necessary conditions for good teaching and learning activities, especially teacher-student communication. It is in this context that the importance of classroom acoustics is highlighted. Therefore, this work aimed to evaluate the acoustic quality in two classrooms. To this end, the perception of teachers and students about the noise inside and outside the classroom was investigated through questionnaires. Then, the background noise levels and the reverberation time values ​​inside the classrooms were evaluated in situ. These results were compared with the assessment of the subjective perception of the questionnaires. The levels of background noise found in classrooms were above what NBR 10152 recommends. The subjective assessment showed that students and teachers perceive the noise in classrooms and consider them bothersome. According to the teachers, noise is a factor that negatively affects teaching. In conclusion, the results obtained in this work show the lack of acoustic comfort in classrooms and highlight the need for interventions.

Environmental Acoustic Comfort in the Built Environment

The acoustic quality of classrooms has a strong influence on the teaching and learning process. This interference assessed using the impulsive technique to measure the rate of speech transmission (STI), reverberation time (RT) and sound definition (D50). These are the most relevant acoustic descriptors in the assessment of classrooms, where verbal exposure is the means of communication between teachers and students. The evaluation took place in two buildings of the Federal University of Paraná (UFPR), built in the 1960s and another in 2016. The measured values ​​of STI, provided in the classrooms' actual acoustic conditions, were used as an adjustment parameter for simulations made with the software ODEON. After carrying out the measurements and simulations, the dimensioning of improvements was possible. The acoustic simulations presented suggestions to qualify the quality of the classrooms' acoustic comfort, ensuring that teaching and learning to do not suffer losses due to the physical structure of the classrooms. The measured values ​​of STI, RT and D50 show that, in the old building, except for a single classroom that preserves the original ceiling that had a high sound absorption coefficient, it has reasonable values, below the ideal for classrooms, according to the IEC 60268-16 (2011) standard. The investigation showed that the rooms with a roof replaced by a PVC covering had a sharp drop in acoustic quality. The newest building has classrooms with proper acoustic comfort conditions.

A Review on Indoor Environment Quality of Indian School Classrooms

The progress of Indoor Environmental Quality (IEQ) research in school buildings has increased profusely in the last two decades and the interest in this area is still growing worldwide. IEQ in classrooms impacts the comfort, health, and productivity of students as well as teachers. This article systematically discusses IEQ parameters related to studies conducted in Indian school classrooms during the last fifteen years. Real-time research studies conducted on Indoor Air Quality (IAQ), Thermal Comfort (TC), Acoustic Comfort (AcC), and Visual Comfort (VC) in Indian school classrooms from July 2006 to March 2021 are considered to gain insight into the existing research methodologies. This review article indicates that IEQ parameter studies in Indian school buildings are tortuous, strewn, inadequate, and unorganized. There is no literature review available on studies conducted on IEQ parameters in Indian school classrooms. The results infer that in India, there is no well-established method to assess the indoor environmental condition of classrooms in school buildings to date. Indian school classrooms are bleak and in dire need of energy-efficient modifications that maintain good IEQ for better teaching and learning outcomes. The prevailing COVID-19 Pandemic, Artificial Intelligence (AI), National Education Policy (NEP), Sick Building Syndrome (SBS), Internet of Things (IoT), and Green Schools (GS) are also discussed to effectively link existing conditions with the future of IEQ research in Indian school classrooms.

NOISE LEVELS EMITTED BY AGRICULTURAL TRACTORS WITH AND WITHOUT IMPLEMENTS ACTIVATION

Níveis de ruído emitidos por tratores agrícolas com e sem acionamento de implementos Os níveis de ruído emitidos pelas máquinas agrícolas podem ser prejudiciais à saúde do trabalhador e, por vezes, negligenciados no meio rural. Este trabalho teve como objetivo mensurar os níveis de ruído emitidos por três tratores agrícolas de diferentes potências acionando dois tipos de implementos para avaliar se havia riscos à saúde dos operadores e trabalhadores de apoio ao redor da operação. Os dados de ruído foram coletados por decibelímetro em dez pontos de cada lado da máquina (frente, trás, esquerda e direita) para um total de 40 pontos ao redor de cada trator. Três tratores diferentes foram avaliados em diferentes cenários: sem implemento, acoplando e acionando uma esparramadora de corretivo e acoplando e acionando uma enxada giratória. O trator foi estacionado no centro da mistura com uma rotação do motor que garantiu 540 rotações por minuto (RPM). para a tomada de potência (TDP) durante toda a coleta de dados. Os dados foram analisados ​​por meio de gráficos, regressão linear e análise de agrupamento hierárquico. Os resultados indicaram que os níveis de pressão sonora em todas as situações estudadas ultrapassam os limites da norma regulamentadora (NR) 15, tornando os protetores auditivos indispensáveis ​​durante a jornada de trabalho. Palavras-chave: ergonomia; conforto acústico; mecanização agrícola; nível de pressão sonora. ABSTRACT: The noise levels emitted by agricultural machines can be harmful to the worker's health, and it is sometimes neglected in rural areas. This work aimed to measure the noise level emitted by three agricultural tractors of different power activating two types of implements to assess whether there were risks to operators' health and the supporter workers around the tractor. The noise level data were collected using a decibel meter in ten points on each machine side (forward, rear, left, and right) for a total of 40 points around each tractor. Three different tractors were evaluated in different scenarios: without any implement, coupling and activating a spreader, and coupling and activating a rotary hoe. The tractor was parked at the centre of the mash with an engine speed that ensured 540 rotation per minute (RPM). to the power take-off (PTO) during the entire data collection. The data were analyzed by charts, linear regression, and hierarchical clustering analysis. The results indicated that the sound pressure levels in all of the studied situation exceed the standard's limits regulatory standard 15, making hearing protectors essential during the working day. Keywords: ergonomics; acoustic comfort; agricultural mechanization; sound pressure level.

The Effectiveness of Facial Expression Recognition in Detecting Emotional Responses to Sound Interventions in Older Adults With Dementia

This research uses facial expression recognition software (FaceReader) to explore the influence of different sound interventions on the emotions of older people with dementia. The field experiment was carried out in the public activity space of an older adult care facility. Three intervention sound sources were used, namely, music, stream, and birdsong. Data collected through the Self-Assessment Manikin Scale (SAM) were compared with facial expression recognition (FER) data. FaceReader identified differences in the emotional responses of older people with dementia to different sound interventions and revealed changes in facial expressions over time. The facial expression of the participants had significantly higher valence for all three sound interventions than in the intervention without sound (p < 0.01). The indices of sadness, fear, and disgust differed significantly between the different sound interventions. For example, before the start of the birdsong intervention, the disgust index initially increased by 0.06 from 0 s to about 20 s, followed by a linear downward trend, with an average reduction of 0.03 per 20 s. In addition, valence and arousal were significantly lower when the sound intervention began before, rather than concurrently with, the start of the activity (p < 0.01). Moreover, in the birdsong and stream interventions, there were significant differences between intervention days (p < 0.05 or p < 0.01). Furthermore, facial expression valence significantly differed by age and gender. Finally, a comparison of the SAM and FER results showed that, in the music intervention, the valence in the first 80 s helps to predict dominance (r = 0.600) and acoustic comfort (r = 0.545); in the stream sound intervention, the first 40 s helps to predict pleasure (r = 0.770) and acoustic comfort (r = 0.766); for the birdsong intervention, the first 20 s helps to predict dominance (r = 0.824) and arousal (r = 0.891).