Comfort Limits Research Articles

The vestibular implant: effects of stimulation parameters on the electrically-evoked vestibulo-ocular reflex.

The vestibular implant is a neuroprosthesis which offers a potential treatment approach for patients suffering from vestibulopathy. Investigating the influence of electrical stimulation parameters is essential to improve the vestibular implant response. Optimization of the response focuses on the electrically evoked vestibulo-ocular reflex. It aims to facilitate high peak eye velocities and adequate alignment of the eye movement responses. In this study, the basic stimulation parameters of the vestibular implant were tested for their effect on the electrically evoked vestibulo-ocular reflex. Four stimulation parameters, including the stimulation amplitude, phase duration, stimulus rate and speed of change of stimulation, were systematically tested in a cohort of nine subjects with a vestibulo-cochlear implant. These parameters were tested to evaluate their effect on fitting settings (i.e., threshold of activation, upper comfortable limit and dynamic range) as well as on the electrically evoked vestibulo-ocular reflex (peak eye velocity and alignment). It was confirmed that, in addition to current amplitude, the peak eye velocity of the response can be increased by increasing the phase duration and pulse rate. Both parameters have little effect on the alignment of the eye response. However, a longer phase duration decreased the range between the threshold of activation and the upper comfortable limit of the electrical stimulation (i.e., dynamic range). Furthermore, these results show that next to the amplitude of the stimulation, the speed of change in stimulation has a determinative positive effect on the peak eye velocity. The observations in this study imply that the vestibular implant response, in terms of peak eye velocity, can be optimized with a higher pulse rate and longer phase duration. However, this comes at a trade-off between the dynamic range and power consumption. This study provides essential insights for fitting strategies in future vestibular implant care.

PRELIMINARY DATA ON COAT COVERAGE AND GROOMING INTERFERING WITH THE THERMAL COMFORT OF LHASA APSO AND SHIH TZU DOGS

The objective of this report was to investigate the effects of grooming on thermal comfort in Lhasa Apso and Shih Tzu dogs exposed to different ambient temperatures. A randomized block design in a 3 x 2 factorial scheme was used, with 3 different temperatures associated with whether the animal was groomed or not. Six adult dogs, consisting of two Lhasa Apsos and four Shih Tzus, were used. The dogs were exposed to temperatures of 17°C, 25°C, and 33°C both before and after grooming. Physiological parameters (blood pressure, heart rate, respiratory rate, rectal temperature, ambient temperature, ITU, and body surface temperature) were measured using infrared thermography with a portable IRT camera. The images were analyzed using FLIR Tools™ software with an emissivity of 0.97. Variance analysis was performed to evaluate the isolated effects and interactions between the factors of coat coverage and ambient temperature at the 5% significance level. No interaction was found between the treatments, nor were there isolated effects of the factors on the physiological parameters evaluated. A temperature of 33°C was associated with a higher rectal temperature (p<0.05) in the animals. Ungroomed dogs exposed to temperatures of 25°C and 33°C had ITU values above the thermal comfort limit. In terms of body temperature, there was a significant interaction effect between coat coverage and the environment under different climatic conditions (p<0.05). The surveyed grooming dogs exhibited greater body temperatures at all temperatures tested, namely, 17°C, 25°C, and 33°C. Grooming did not reduce the effects of thermal stress caused by different climatic conditions, indicating that grooming is not advisable for these animals

Thermal environment analysis and parameters optimization of a novel hot-air phase change heating bed

Maintaining indoor heating consumes significant energy; personalized heating can reduce this consumption. Existing bed-based heating devices have drawbacks in terms of temperature distribution and susceptibility to weather influences. In this paper, a hot-air phase change heating bed (HAPCHB) is proposed, which can heat the indoor thermal environment during the day and the bedding thermal environment at night. The theoretical analysis and simulation model of the new heating bed is established, and the experimental platform for analyzing the thermal environment building effect is built, which verifies the accuracy of the numerical simulation results. The experimental and simulation results show that the thermal inertia of the envelope has a great influence on the room temperature, but has little influence on the bed board temperature under the experimental conditions. Both indoor and bed board temperatures can keep the lower limit of thermal comfort for 12 h continuously. With the increase of phase change material (PCM), the thermal performance of the system is enhanced and attenuated, and the thermal performance of PCM-1.4 scheme is better. The rate of indoor temperature drop is similar under three heating times, but the performance of room temperature and bed board temperature is better at 6 h and 8 h respectively. The research results provide basis and guidance for improving indoor heating effect by HAPCHB.

Perceptibility and Pain Thresholds in Low- and High-Frequency Alternating Current Stimulation: Implications for tACS and tTIS

AbstractTranscranial electrical stimulation (tES) has emerged as a promising tool for neuromodulation, but its application is often limited by the discomfort associated with higher stimulation intensities. Newer variants like transcranial temporal interference stimulation (tTIS) utilize high-frequency alternating currents (≥ 500 Hz) to penetrate deeper brain regions while mitigating perceptual discomfort. This study sought to examine sensation and pain thresholds across various stimulation frequencies of alternating currents, aiming to explore the boundaries of comfortable intensities. Additionally, we sought to evaluate the efficacy of an anesthetizing topical cream in increasing participant comfort and potentially extending the range of tolerable stimulation levels. We recruited 37 participants and applied alternating current stimulation to the head at various frequencies (10 Hz, 20 Hz, 500 Hz, 1000 Hz, and 2000 Hz) to determine intensity-dependent perception and pain thresholds. Additionally, thresholds were determined under the influence of a topical anesthetic. Our findings confirm that as stimulation frequency increases, perceptibility decreases, with higher frequencies allowing a manyfold increase in stimulation intensity before becoming perceptible or causing pain. Additionally, the anesthetizing cream was efficacious in further reducing perceptibility and pain sensations across all frequencies. This study lays the groundwork for future research by establishing comfortable limits for stimulation intensities, particularly in the context of high-frequency stimulation. The reduced perceptibility of high-frequency stimulation, coupled with the effectiveness of anesthetizing creams, enables the administration of higher stimulation intensities for more potent neuromodulatory interventions without causing discomfort.

Ride comfort and impact factor of a seven-span continuous cable-stayed bridge

This study was conducted to investigate the vibration serviceability and impact coefficient of a seven-span continuous cable-stayed bridge planned for an expressway extension using a three-dimensional vehicle–bridge coupled vibration analysis. For the bridge design, deflection under the designed live load of the continuous cable-stayed bridge did not meet the deflection limit specified in “Japanese Design Specifications for Highway Bridges.” The excessive deflection indicates the possibility of poor vibration serviceability. To clarify the bridge vibration serviceability, the dynamic responses of the bridge and passing vehicles were examined using the three-dimensional vehicle–bridge coupled vibration analysis. The three-dimensional analysis was validated by comparing the vibration response of a single-span steel cable-stayed bridge in service subjected to vehicle running tests with those numerical responses from the three-dimensional analysis. The ride comfort of vehicles on the bridge was assessed in terms of vibration serviceability according to the ISO 2613-1 international standard for evaluating whole-body vibration exposure. The observation from the simulation-based investigation demonstrated that the vehicle response does not exceed the ride comfort limit irrespective of vehicle, road, and running conditions. In other words, the findings confirmed a negligible effect of large deflections on driving safety. The impact factors were found to be less than 1.05 for the main girder, less than 1.03 for the main tower base, and less than 1.04 for the cable. The impact factor was greatest when several vehicles were running at resonant headway.

Subjective evaluation of thermal comfort of tropically acclimatized subjects in air conditioned, naturally ventilated and radiant cooling environments

The thermal sensation of people is subjective. It depends on the external climatic condition and thermal history of a person. Thermal comfort standards suggest a narrow temperature range to assert an environment as comfortable or otherwise. It is important to evaluate people’s thermal perception in different climatic regions and set comfort limits based on their thermal perception. This study evaluates the thermal perception of subjects in hot and humid climatic regions at higher indoor temperatures and air velocities. Three different thermal environments chosen for the study are air conditioned (AC), naturally ventilated (NV), and radiant cooling (RC) thermal environments. The study shows that more than 80% of subjects voted as comfortable in AC and RC thermal environments for the measured Top and va range of 25.3 – 28.4℃/0.1 – 0.3m/s and 25.9 – 29.1℃/0.1 – 0.9m/s respectively. The findings gathered from the study in NV environment indicate that 68% of subjects opt for the use of table fans over ceiling fans. The subjects' free control of air movement improves their thermal sensation over no control of air movement, indicating that they prefer table fans and free control of air movement. In AC, NV, and RC thermal environments, humidity and air quality remain uncontrolled. In AC and RC thermal environments, less than 20% of subjects voted unacceptable for the humidity sensation and Perceived air quality (PAQ) scales in nearly all the studied experimental conditions. In NV thermal environment, the percentage of subjects voting dissatisfied on the humidity sensation scale and PAQ scale is 30-52% and 26-37%, respectively. This outcome shows that a thermally comfortable environment with air movement improves subjects' humidity sensation and PAQ even when humidity and air quality are unaltered. The study points out that air velocity played a vital role in influencing the thermal sensation, humidity sensation and perceived air quality of subjects in the three studied thermal environments. Further the study shows that with free control of air movement will significantly aid in rising the comfort temperature band of tropically acclimatized subjects. Practical application The study shows the variation in limits of thermal comfort indices such as operative temperature and air velocity for tropically acclimatized subjects in three thermal environments. The same group of subjects participated in the subject study conducted in air conditioned, naturally ventilated and radiant cooling thermal environments. The outcomes indicate that subjects are comfortable at higher indoor temperature and air velocity. Further the outcomes showed that the humidity and air quality sensation of subjects is influenced by the subjects’ thermal sensation and air velocity.

Human–structure interaction effects on lightweight footbridges with tuned mass dampers

The aim of the work is to explore how the interaction between pedestrians and a bridge deck could affect the effectiveness of tuned mass dampers (TMD) in suppressing the vibrations of lightweight footbridges. To this end, a human–structure interaction (HSI) model is built in a modal dynamic analysis framework, and it is applied to a lightweight footbridge subject to a large number of pedestrian arrangements with near-resonant walking frequencies. Compared with the response ignoring HSI, the results show that the interaction between the dynamic response of the pedestrians and the structure can reduce the vibrations in the deck, but they exceed comfort limits based on peak and root mean square (RMS) acceleration criteria. In order to reduce the oscillations to a comfortable level, a TMD located at midspan has been designed following classical optimisation methods that neglect HSI. The efficiency of the damper in resonant conditions is demonstrated in the time and frequency domains, even under a large number of synchronised pedestrians interacting with the structure, suggesting that crowds do not introduce important detuning effects in the TMD.

Impact of Energy-Consuming Air Conditioning Systems on People's Thermal Comfort and Preferences: Comparative Study of Iraq and Gulf Cooperation Council Countries

This study investigates the impact of the intense usage of air-conditioning systems on the thermal comfort requirements of building occupants. It compares the thermal comfort requirements of building occupants in Iraq and Gulf Cooperation Council (GCC) countries. Iraqis have limited usage of air-conditioning units, whilst people in GCC countries intensely operate these systems. Research work underpinning this article involved undertaking a year-long thermal comfort survey in Iraq, and an intensive analysis of thermal comfort studies conducted in GCC countries. Results show that, in Iraq, people experience a 2–50 °C annual indoor temperature range, and their annual comfort range is 14–35 °C. In GCC countries, due to the intense usage of air-conditioning systems, the widest recorded annual indoor temperature range is 17.2–31.0 °C, and the widest annual comfort range is 20.0–27.8 °C. These results demonstrate the significant impact of air-conditioning systems on narrowing the thermal comfort limits of building occupants leading to high energy consumption. This study presents a novel comparison between two cases highlighting the impact of air-conditioning systems on the thermal comfort requirements of building occupants. The results of this study can be used to inform the development of thermal comfort standards that better consider people’s adaptation capabilities to help reduce energy consumption for heating and cooling purposes.

Evaluasi Kenyamanan Termal Masjid Baitul Musyahadah Kota Banda Aceh

Many mosques in the city of Banda Aceh have used artificial ventilation systems to achieve thermal comfort conditions in the interior of the mosque. Meanwhile, the Baitul Musyahadah Mosque, which is classified as a large mosque in Banda Aceh City, currently still maintains an open mosque building design and utilizes a natural ventilation system. In this community service activity, field research was carried out with the aim of evaluating thermal comfort in the interior of the Baitul Musyahadah Mosque. The research method uses a quantitative descriptive approach by collecting data through field observations and measurements, according to variables that influence thermal comfort including air temperature, air humidity and wind speed. The results obtained regarding the thermal comfort conditions of the space in the Baitul Musyahadah Mosque are (a) the average value of the effective temperature in the building falls within the limits of a warm comfortable sensation; (b) the average value of air humidity in the building is within comfortable limits; (c) the wind speed value in the room is very weak. Furthermore, based on the results of the analysis and simulation of thermal comfort in the mosque, improvements to the opening aspects which influence increasing wind speed in the mosque are recommended to support passive thermal comfort.

GLABELLAR FLAP RECONSTRUCTION FOR DEFECTS BELOW MEDIAL CANTHUS

Background: Glabellar plastic is a method used for reconstructing the medial defects that use the available surrounding tissue, and in particular, that of the glabellar region. Most authors are of the opinion that this plastic is suitable for defects that reach the medial canthal area and do not pass down to the lower eyelid. Aim: To present the glabellar flap technique as an option for the reconstruction of defects that extend below the medial canthus, which is an application outside the recommended indications of this technique. Results: The postoperative outcome was good in all patients. Positional anomalies are within the limits of functional comfort. None of the patients requested postoperative cosmetic correction of the surgical defect. Conclusion: We demonstrated the possibility of using this technique below the level of the medial canthus. It carries risks for the appearance of positional abnormalities of the eyelids after surgery, but if the influence of laxity, skin texture and shape of the operative defect is properly taken into account, this technique provides a good alternative to combined surgery.

Thermal comfort in school children: Testing the validity of the Fanger method for a Mediterranean climate

Thermal comfort is an essential factor when designing or refurbishing schools because it helps to improve wellbeing and academic performance. However, little attention has been paid to assessing the thermal comfort level of children. Previous studies on thermal comfort have mainly focused on adults' perceptions, extrapolating their results to all ages without cross-checking them for relevance. The aim of this research was to determine whether children perceive temperature in a similar way to adults and if their thermal comfort limits are the same. A school in south-eastern Spain was selected as the case study. Thermal comfort surveys of children were conducted and compared with analytical calculations obtained using the Fanger method. The results showed that the Fanger method was not valid for the estimation of children's thermal comfort, especially in girls and younger children. The novelty of this research demonstrates that children have specific thermal comfort requirements that are not covered by current standards and calculation methods, such as the Fanger method. Analysis also determined the correction coefficients necessary for adapting Fanger's analytical method to children according to age and gender in BShs climate.

The effect of climate index on growth values from birth to breeding in Akkaraman sheep.

Under specific agroclimatic conditions, growth is an adaptability parameter resulting in reduced performance with decreasing animal comfort of a sheep breed. In this study, a total of 1011 lambs' live weights (LW) and average daily weight gains (ADG) in 16 different farms between 2018 and 2020 (birth to 18 months) were determined in Akkaraman herds raised in Çankırı Province of Turkey. Comprehensive Climate Index (CCI) was examined to determine the effect of climate. Thermal comfort limits in CCI values were classified as CCI-1.cold (≤ 5 ℃), CCI-2.comfort (5-25 ℃), and CCI-3.warm (≥ 25 ℃). The climatic values that all lambs examined were exposed to according to index value groups in periods from birth to 18 months of age were prepared daily. The lambs were exposed to comfort environment in the majority of the days in the MP0-3 (77.7%) and MP12-18 (50.1%) periods. The lambs mostly in the MP3-6 period (72.2%) were above the warm stress threshold, but in the MP6-12 period, 54.7% were above the cold stress threshold. Overall mean LW of lambs at birth, at 3, 6, 12, and 18 months were 4.29 kg, 35.1 kg, 39.1 kg, 45.4 kg, and 52.6 kg, while the ADG values between birth-3 months, 3-6 months, 6-12 months, and 12-18 months were 341.8 g, 54.5 g, 42.9 g, and 56.8 g respectively. Periodically, CCI values were realized as 10-15, 25-30, and 18-22 in the growth periods of 0-3, 3-6, and 12-18 months, respectively, and ADG values of the lambs were found to be similar within their own periods. However, when the CCI values of the lambs increase to 5 and above in the 06-12-month period, there is a decrease in their live weight. As a result, climatic index values did not have a negative effect on the growth and development values of lambs in cold conditions in general, but warm conditions affected the animals negatively.

Relative comparison of the benefits of wall envelope insulation materials in the South African energy zones, subject to the new national building energy efficiency standards

Introduction: South Africa is ranked among the 20 highest greenhouse gas (GHG) emitters worldwide, mainly due to its heavy reliance on coal for energy. The residential building industry can play a significant role towards the minimization of both GHG emissions and energy consumption. This research assesses the beneficial impacts of utilizing wall envelope insulation measures using five insulation materials, for a detached residential building, within the seven energy zones of South Africa in accordance with the South African National code for Building energy efficiency (SANS10400-XA).Methods: Lifecycle analysis (for 50 years), regression methods and sequential search techniques of building energy modelling were used to determine both the energy saving implications of adopting the insulation materials (at various levels of thickness), and their corresponding energy payback periods. The study area consisted of eight selected locations representing all the seven energy zones in South Africa (Welkom, Witbank, Thohoyandou, Cape Town, Pretoria, Ixopo, Sutherland, and Fraserburg).Results: Sutherland (zone 6), Cape Town (zone 4) and Fraserburg (zone 7) benefitted most from energy savings due to application of insulation measures. Witbank (Zone 2), Thohoyandou (zone 3) and Pretoria (zone 5) never benefitted from application of wall envelope insulation (in terms of energy savings). Cellulose and straw yielded the lowest payback periods. Generally, polyurethane yielded the highest net energy savings at lower insulation thickness levels, while cellulose was preferable at higher insulation thickness levels in Welkom (zone1) Cape Town (zone 4), Ixopo (zone 5H), Sutherland (zone 6) and Fraserburg (zone 7).Discussion: Lower optimal wall envelope insulation thicknesses (that maximized energy savings) appeared to correspond to locations with higher annual temperature ranges. Higher temperature ranges (hence, higher degree days) would ensure that more energy is saved in order to keep the indoor temperatures within the acceptable comfort limits, due to application of insulation. However, the selection of insulation material is also influenced by other factors such as resistance to insect and mould attack (which easily affect bio-insulation materials), fire retardancy, durability (which affects cellulose), sound proofing, structural strength, and resistance to water vapour.

Toward Sustainable Indoor Environments: Assessing the Impact of Thermal Insulation Measures on Air Quality in Buildings—A Case Study in Temuco, Chile

In Chile, an Atmospheric Decontamination Plan (PDA) has been developed to reduce concentrations of fine particulate matter (PM 2.5) in cities deemed “saturated” with these particles. The plan includes various measures, such as the thermal insulation of homes and the replacement of heaters. This study presents an analysis of the indices of four indoor air quality variables (temperature, humidity, carbon dioxide, and PM 2.5) in different types of homes with varying levels of PDA implementation in the city of Temuco, Chile. Regarding the temperature variable, only one type of home was found to be within comfort limits, with an average of 20.6 °C and a variation of ±3.52 °C (SD). Concerning humidity, independently owned homes with complete and moderate ADP implementation had average humidity levels between 64.82% ± 7.19% and 55.6% ± 6.11%, respectively. For CO2, only homes with moderate implementation showed averages slightly below (average 991 ppm) the maximum allowed (1000 ppm). As for PM 2.5, all homes exceeded the standard, ranging from 44.4 µg/m3 to 130 µg/m3, with very high variations. This demonstrates that PM 2.5 concentrations consistently exceeded the limits established by the World Health Organization (15 µg/m3).

Robust MPC with Support Vector Clustering-based Parametric Uncertainty Set for Building Thermal Control

Control systems are essential to support the use of building structures as short-term thermal energy storage (TES). Due to modeling and forecast imperfections, the controller must be able to deal with uncertainties. This paper proposes a robust model predictive controller (MPC) with a new uncertainty set construction technique to regulate the heat supply in a building envelope. We extend the Support Vector Clustering-based set construction technique to estimate modeling and forecast uncertainty sets. Subsequently, we integrate the sets into a Min-Max MPC framework to ensure robust feasibility by tightening the constraints. The resulting controller successfully deals with modeling and forecast uncertainties. The quality of the presented framework is compared with a nominal MPC and a robust MPC with different uncertainty set estimates. On the basis of a numerical simulation, we demonstrate that the proposed controller successfully maintains the room temperature within the comfort limits. The result also shows that our MPC is less conservative than the controller designed using a box-shaped non-falsifed parametric uncertainty set.

Resistance of Kalmyk cattle breed to high ambient temperatures of the highlands of the North Caucasus

The purpose of the research is to establish indicators of heat resistance and study the growth of Kalmyk cattle youth in different natural, climatic, organizational and technological conditions in the highlands of the Kabardino-Balkarian Republic. The investigations were carried out in LLC «Dargan» (Chereksky district, in village Gerpegezh) and LLC «Malka» (Zolsky district, in village Malka) of the Kabardino-Balkarian Republic of the Kalmyk breed bulls during the period of grazing (from 7 to 12 months). The highest values of the heat resistance index and tolerance coefficient were recorded at the beginning of the grazing period in species of both farms, when the ambient temperature during the day was within comfortable limits for the species as a whole. Subsequently, the heat resistance indicators were decreased by the middle of the analyzed period of detention, which is explained by the temperature stress for the body of the experimental animals. However, temperature conditions and resistance were restored to their original values for them by the end of the experiment. Inter-farm divergences in growth intensity in age period of 7-9 months were 31 g (P<0.95), 9-12 months - 65 g (P<0.999) and for the entire period - 52 g (P<0.99). The largest absolute increase in live weight over the analyzed period was distinguished by bulls from LLC «Malka», which were under other conditions, recorded the lowest feed costs per 1 kg of live weight gain. Thus, the differences in the cost of energy feed units in comparison with individuals from «Dargan» LLC were 0.18, digestible protein was 11 g.

Transport distance influenced the proportion of skin lesions in finishing pigs and negatively affected animal welfare

Transport is a relevant process during pigs’ lives because of its impact on animal welfare. Considering commercial conditions, several factors vary between journeys; therefore, it is important to establish the influence of transport distance on skin lesion scores in finishing pigs, considering weather and vibration conditions. Skin lesion score was assessed in 649 finishing pigs at the farms before loading, with a five-point scale (0= none to 4 = ≥ 16 superficial lesions or > 10 deep lesions), and at the slaughterhouse after unloading. Three transport distances were evaluated (short, intermediate and long), in which microclimatic and vibration conditions were monitored from the vehicle’s compartments. Intermediate distances showed higher proportions of worst score (4) at the front part, whereas long distances presented worst score at the middle and hind quarters. Short distances displayed higher proportions of worst score at ears. Temperatures inside the vehicle were above the thermal comfort limit for pigs, providing a heat stress condition. Vibrations were higher sideways than in the vertical and longitudinal directions. Transport under tropical conditions negatively affected the skin injuries score, indicating a higher incidence of skin wounds at the slaughterhouse than in the farms. Body parts can be affected differently by distance, considering skin lesion scores.

Spatial and temporal variations of microclimate and outdoor thermal comfort in informal settlements of warm humid Dar es Salaam, Tanzania

In developing countries, urbanization is dominated by the growth of informal settlements which represents 40–80% of major cities. The challenges brought up by the growth of informal settlements spans from social-economic to environmental. Previously, upgrading of the informal settlements focused on social-economic aspects such as provision of necessary services for the residents, whereas the quality of the outdoor thermal environment has not received much attention. This paper entails to investigate the potential of upgrading the outdoor thermal environment in informal settlements in the warm humid city of Dar es Salaam, Tanzania through examining the influence of addition of trees with different Leaf Area Index (LAI) and incremental increase of buildings heights. The study uses simulation as a method for analysis of the warm season and calculates the Physiological Equivalent Temperature (PET) as a thermal index. Results show substantial improvement of both microclimate and outdoor thermal comfort. Incremental increase of buildings heights in a street canyon to 12, 18, and 24 m leads to the reduction of PET by 2.5, 2.8, and 3.8 °C respectively at 2:00 p.m. Similarly, applying LAI's of 2, 4, and 6 m2/m2 leads to reduction of the mean radiant temperature by 7.9, 10.1, and 12.2 °C; while PET was reduced by 3.9, 4.7, and 5.6 °C respectively at 2:00 p.m. Nonetheless, upgrading of informal settlements shows marginal influence on the reduction of air temperature. Despite the noted thermal improvement in the studied area, the thermal comfort limits of the warm season were difficult to reach. The findings suggest that addition of vegetation is the economically most effective way for upgrading thermal conditions in informal urban fabric areas.

Thermal perception and satisfaction of Italian students in distance (home) learning vs face-to-face learning environments during the heating season

During the 2020-2021 COVID-19 pandemic situation, millions of high school students in Italy had to adapt a room in their home for partial distance learning. This paper investigates the thermal perception and satisfaction with the thermal conditions expressed by 45 teenage students alternating between Distance Learning (DL) and Face-to-face learning (FL) during that period. Students completed questionnaires about their perception and satisfaction with the thermal environment while air temperature and humidity were monitored for 14 weeks. The thermal conditions in the classrooms, where students attended classes every other day, were also monitored during this time. The results show that students at home experienced a high percentage of time with conditions outside recommended comfort limits. Nevertheless, most of the students expressed a TSV equal to 0. In addition, the proposed long-term thermal discomfort indicators, such as running mean of the indoor air temperature, correlated rather poorly with subjective votes. This may indicate that different indices should be considered when analyzing mid-term subjective thermal comfort evaluations.

A Wearable Monitoring Device for COVID-19 Biometric Symptoms Detection

BackgroundMonitoring COVID-19 symptoms has become a critical task in controlling the spread of the virus and preventing hospitalizations. Aiming to contribute to efficient monitoring solutions, this article presents the development and testing of a wearable device capable of continuous monitoring biometric signals associated with the presence of COVID-19, such as the heart rate, the blood oxygen saturation, and the body temperature. MethodsTo ensure continuous monitoring the device is designed to be worn in the ear. Here, the temperature is measured through a non-contact infrared temperature sensor placed inside the ear canal while the heart rate and the pulse oximetry signals are monitored through a photoplethysmography reflective sensor positioned at the earlobe.The proposed device's performance was evaluated by comparing it against a medical certified station. Usability and ergonomics were assessed through users' questionnaires. Additionally, experiments were performed to evaluate the hearing loss when the proposed device is in use. Data was acquired from 30 individuals of different sex, aged between 20 and 43 years old. In relation to usability and ergonomics the variation in ear dimensions was accessed and related to the device's comfort limitations. ResultsThe temperature measurement produced a moderate correlation (R=0.42), despite a higher standard deviation was found in the proposed solution. This is due to the limited variability in temperature data, creating a short measuring range, as only healthy people were tested. The heart rate measurement also showed good correlation (R=0.96), with the proposed solution showing good repeatability with a standard deviation of 6.06 BPM, however, the SpO2 measurement was suboptimal (R=0.14).The ergonomic evaluation revealed that most participants found the device shape comfortable, but some found the dimensions not adequate.Additionally, the device was found to be user-friendly, with most participants reporting that they found it to be intuitive, and none reported a major loss in hearing in a normal conversation, however, there's a negligible loss of approximately 0.56 dB. ConclusionsDuring this study, it was possible to develop and evaluate a wearable device that was suggested for monitoring biometric signals. The device demonstrated great reliability in temperature and heart rate measurement but showed limitations in the accuracy of pulse oximetry. The main contribution of this work is the evaluation of a continuous non-invasive monitoring concept for COVID-19 related biometric signals, which indicates good applicability in the case study.