RESUMO
In this work, the external and internal airflow analysis in an urban bus is carried out through computational fluid dynamics. The research addresses the study of the internal flow to estimate the air change rate caused by the opening of windows. Two cases are considered: fully opening and partially opening the windows, and three bus speeds of 20, 40, and 60 km/h are assessed. The quantification of the air flow rate through the windows clearly displays that air enters through the rear windows and exits the bus through the front windows. This effect is explained by the pressure distribution in the outer of the bus, which causes the suction of the indoor air. At low bus speeds, the incoming air flow rate increases linearly with the speed, but the improvement is lower for high speeds. The theoretical air change time at 20 km/h is around 25.7 s, which is 9 times lower than expected by using HVAC systems. On the other hand, the estimation of the real air renewal time by solving a concentration shows that 40 s are needed to exchange 85% of the internal air of the bus. The research also assesses the effect of different levels of occupation inside the bus. Results are conclusive to recommend the circulation with full or partial window opening configurations in order to reduce the risk of airborne disease transmission.
Assuntos
Movimentos do Ar , Poluição do Ar , Veículos Automotores , Poluição do Ar/análiseRESUMO
This study presents the first local measurements of metals in snow from the Argentine Central Andes. Cu, Pb and Zn were selected as specific tracers of anthropogenic local emission sources in the study area. Snow samples were collected during winter (2014, 2015 and 2016) at two sites with different characteristics: Punta de Vacas and Vallecitos. The samples were analyzed by ICP-MS, and the average concentrations found were 1.4 µg L-1 (Cu), 2.2 µg L-1 (Pb) and 14.2 µg L-1 (Zn) in the snow samples from Vallecitos, and 5.3 µg L-1 (Cu), 2.6 µg L-1 (Pb) and 24.0 µg L-1 (Zn) in the snow samples from Punta de Vacas. These data and the snowfall amount in each sampling site were statistically analyzed. Results suggested that the levels of metals in the snow are influenced not only by the atmospheric concentrations, but also by the amount of precipitated snow. Additionally, an atmospheric dispersion model, CALPUFF, was applied in the study area to determine the origin of the studied metals and to understand the spatial distribution pattern of the concentrations found. Results showed that the metal atmospheric loads in the study area originated from local sources, especially vehicular traffic and mining. This work represents an important contribution to the knowledge and preservation of the local Andean cryosphere, and it could be used as an input to develop protection policies in the area through the combination of different and complementary tools for the evaluation of air quality.
Assuntos
Poluição do Ar , Metais Pesados , Neve , Oligoelementos , Movimentos do Ar , Monitoramento Ambiental , Metais , Modelos TeóricosRESUMO
I was evaluated the effect of seven different combinations of temperature, air velocity, and relative air humidity on the frequency and duration of eating, drinking, resting, cannibalism, dust bathing, scratching, ground pecking, shivering, and stretching behaviors of turkeys at three different ages. The combinations tested of temperature, relative air humidity, and air velocity were, respectively: 1 (22 °C, 50%, 1 m/s); 2 (26.2 °C, 73.2%, 0.45 m/s); 3 (26.6 °C, 71.2%, 1 m/s); 4 (28.9 °C, 72%, 1.4 m/s); 5 (31.1 °C, 85%, 0.45 m/s); 6 (34.1 °C, 82.1%, 1 m/s); and 7 (34.4 °C, 82.1%, 1.4 m/s) for three ages of birds (61, 96, and 131 days of age). Seven birds were housed per pen, at a density of 3 males/m2, totaling 147 birds in the entire experiment. Each combination was applied for 5 days. The data were analyzed considering the number of times the bird performed the behavior and the time it performed (in seconds). Each pen was considered a repetition. A comparison of the medians was used to compare the treatments by each age. The results showed that young birds were more likely to suffer from the combination of low temperature and high air velocity, reducing their frequency of normal behaviors. Increased humidity at a low temperature raised the frequency of scratching, shivering, and cannibalism behaviors leading to poorer bird welfare. It is recommended that the temperature, relative air humidity, and air velocity combination of 26.6 °C; 71.2%; and 1 m/s, respectively, for young birds, and 22 °C; 50%; and 1 m/s, respectively, for older birds should be used.
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Movimentos do Ar , Comportamento Animal , Umidade , Temperatura , Perus/fisiologia , Criação de Animais Domésticos , Animais , MasculinoRESUMO
Fungi disperse spores to move across landscapes and spore liberation takes different patterns. Many species release spores intermittently; others release spores at specific times of day. Despite intriguing evidence of periodicity, why (and if) the timing of spore release would matter to a fungus remains an open question. Here we use state-of-the-art numerical simulations of atmospheric transport and meteorological data to follow the trajectory of many spores in the atmosphere at different times of day, seasons, and locations across North America. While individual spores follow unpredictable trajectories due to turbulence, in the aggregate patterns emerge: Statistically, spores released during the day fly for several days, whereas spores released at night return to ground within a few hours. Differences are caused by intense turbulence during the day and weak turbulence at night. The pattern is widespread but its reliability varies; for example, day/night patterns are stronger in southern regions. Results provide testable hypotheses explaining both intermittent and regular patterns of spore release as strategies to maximize spore survival in the air. Species with short-lived spores reproducing where there is strong turbulence during the day, for example in Mexico, maximize survival by releasing spores at night. Where cycles are weak, for example in Canada during fall, there is no benefit to releasing spores at the same time every day. Our data challenge the perception of fungal dispersal as risky, wasteful, and beyond control of individuals; our data suggest the timing of spore liberation may be finely tuned to maximize fitness during atmospheric transport.
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Microbiologia do Ar , Movimentos do Ar , Estações do Ano , Esporos Fúngicos/fisiologia , Atmosfera , Canadá , MéxicoRESUMO
The objective of this study was to evaluate the effects of different environment conditions on productive performance and surface temperatures of Japanese quail (Coturnix coturnix japonica) during the initial stage of laying. In environmental controlled chambers, the birds were subjected to different temperatures and air velocities at the feeder. A total of 216 Japanese quails were distributed randomly in 2 galvanized wire cages, with 3 partitions each and 27 birds/cage. The experimental design consisted of randomized blocks with 2 treatments (air velocity at the feeder: 0, 1, 2, and 3 m/s and air temperature: 17, 23, 29, and 35°C) and 6 replicates. The productive performance was analyzed statistically (Sigma Plot 12.0) by 2-way ANOVA, with treatment means separated by the Tukey test (P < 0.05). To evaluate the main effects and interactions of the factors, the Holm-Sidak multiple comparisons test was performed using a mild condition as the control group (0 m/s). Feed intake did not differ (P > 0.05) among birds reared at temperatures of 23, 29, and 35°C, but higher feed intake was noted at 17°C. The mean values of egg production increased significantly (P < 0.05) with increased air velocity levels. It was observed that there was an increase in egg production and feed intake with the intensification of air velocity at the feeder, regardless of ambient temperature. Egg weight and feed conversion were not affected by air velocity treatments (P > 0.05). There was a significant positive correlation between air temperature and mean surface temperature and head surface temperature. In contrast, a significant negative correlation was observed between air velocity and mean surface temperature and head surface temperature. Productive performance was affected by temperature and air velocity, except for egg weight and feed conversion, which was not influenced by air velocity. Air velocity is important in removing heat from the surface of birds.
Assuntos
Movimentos do Ar , Coturnix/fisiologia , Resposta ao Choque Térmico/fisiologia , Criação de Animais Domésticos/métodos , Animais , Ovos/análise , Feminino , Oviposição/fisiologia , Distribuição Aleatória , Temperatura Cutânea/fisiologia , TemperaturaRESUMO
Pesticides aerial application may results in the drift to neighboring areas if some application technology is not well executed. This phenomenon should be minimized to reduce environmental risks and agricultural production costs. This work aimed to investigate the interaction of environmental conditions, surrounding distance, and application conditions influencing spray drift in aerial applications. Sampling data from aerial sprays were collected during three agricultural years (from 2012 to 2014) in fields cultivated with sorghum, millet, soybean, corn, and cotton. The following variables were evaluated: application swath width, application rate, distance from the applied field, wind speed, relative humidity, and temperature. The estimated Pearson's correlations and path analysis identified that application rate and distance from the applied field and application were the variables that most influenced drift. Equations relating spray drift in function of distance from the applied field and application rate were adjusted in function of the variable, and a response surface model was constructed to estimate drift. The major pesticide class sprayed with aircraft in the Brazilian Cerrado was insecticide, followed by fungicide. This scenario shows the potential hazard risk of spray drift over the environment. The concentration of the drift deposits decreased as surrounding distance and application rate were increased. A mathematical equation of drift prediction was established, where the variables that contributed most to drift deposits were surrounding distance and wind speed. Thus, it is very important to monitor and respect the wind speed limits during the aerial spraying, mainly when there is any risk potential associated with pesticide exposure over the downwind direction.
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Monitoramento Ambiental/métodos , Praguicidas/análise , Agricultura , Movimentos do Ar , Aeronaves , Algoritmos , Brasil , Umidade , Rodaminas/química , TemperaturaRESUMO
Phonotraumatic vocal hyperfunction (PVH) is associated with chronic misuse and/or abuse of voice that can result in lesions such as vocal fold nodules. The clinical aerodynamic assessment of vocal function has been recently shown to differentiate between patients with PVH and healthy controls to provide meaningful insight into pathophysiological mechanisms associated with these disorders. However, all current clinical assessment of PVH is incomplete because of its inability to objectively identify the type and extent of detrimental phonatory function that is associated with PVH during daily voice use. The current study sought to address this issue by incorporating, for the first time in a comprehensive ambulatory assessment, glottal airflow parameters estimated from a neck-mounted accelerometer and recorded to a smartphone-based voice monitor. We tested this approach on 48 patients with vocal fold nodules and 48 matched healthy-control subjects who each wore the voice monitor for a week. Seven glottal airflow features were estimated every 50 ms using an impedance-based inverse filtering scheme, and seven high-order summary statistics of each feature were computed every 5 minutes over voiced segments. Based on a univariate hypothesis testing, eight glottal airflow summary statistics were found to be statistically different between patient and healthy-control groups. L1-regularized logistic regression for a supervised classification task yielded a mean (standard deviation) area under the ROC curve of 0.82 (0.25) and an accuracy of 0.83 (0.14). These results outperform the state-of-the-art classification for the same classification task and provide a new avenue to improve the assessment and treatment of hyperfunctional voice disorders.
Assuntos
Glote/fisiopatologia , Testes Imediatos , Distúrbios da Voz/diagnóstico , Distúrbios da Voz/fisiopatologia , Acelerometria , Adulto , Movimentos do Ar , Diagnóstico por Computador , Feminino , Humanos , Pessoa de Meia-Idade , Smartphone , Prega Vocal/fisiopatologia , Voz , Distúrbios da Voz/etiologia , Adulto JovemRESUMO
A two-week-long intervention study was performed in two classrooms in an elementary school in Costa Rica. Split-cooling air-conditioning (AC) units were installed in both classrooms. During the first week, the air temperature was reduced in one classroom while in the other (placebo) classroom the fans were operated but no cooling was provided. During the second week, the conditions were exchanged to create a 2 × 2 crossover design in which each pupil was their own control. A total of 37 children performed tasks similar to school work and completed questionnaires reporting their thermal sensation and perceptions. Operating the AC units reduced classroom temperature by about 5 K, from about 30 to 25°C. Thermal sensations changed from hot to neutral and slightly cold, and the percentage of children rating the thermal conditions as acceptable increased significantly. Neutral temperature was estimated to be about 27°C. The 11-year-old children performed the language and logical-thinking tasks significantly better in terms of speed at the lower temperature, while the less able pupils performed better on all tasks at the lower temperature. There were no significant effects on accuracy. These results confirm published findings from moderate climates and extend their validity to the tropics. They indicate that acclimatization can increase the optimal temperature for learning.
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Desempenho Acadêmico , Ar Condicionado , Instituições Acadêmicas , Clima Tropical , Movimentos do Ar , Criança , Costa Rica , Estudos Cross-Over , Humanos , TemperaturaRESUMO
Long-range atmospheric transport is one of the most important ways in which persistent organic pollutants can be transported from their source to remote and pristine regions. Here, we report the results of the first Argentinian measurements of organochlorine pesticides in the Antarctic region. During a 9665-km track onboard OV ARA Puerto Deseado, within the framework of Argentinian Antarctic Expeditions, air samples were taken using high-volume samplers and analyzed using GC-µECD. HCB, HCHs, and endosulfans were the major organic pollutants found, and a north-south gradient in their concentrations was evident by comparing data from the Argentinian offshore zone to the South Scotia Sea.
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Movimentos do Ar , Poluentes Atmosféricos/análise , Atmosfera/química , Monitoramento Ambiental/métodos , Hidrocarbonetos Clorados/análise , Praguicidas/análise , Regiões Antárticas , Argentina , Oceanos e MaresRESUMO
Based on Global Network Isotopes in Precipitation (GNIP) isotopic data set, a review of the spatial and temporal variability of δ18O and δ2H in precipitation was conducted throughout central and eastern Brazil, indicating that dynamic interactions between Intertropical and South Atlantic Convergence Zones, Amazon rainforest, and Atlantic Ocean determine the variations on the isotopic composition of precipitation over this area. Despite the seasonality and latitude effects observed, a fair correlation with precipitation amount was found. In addition, Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT) air mass back trajectories were used to quantify the factors controlling daily variability in stable isotopes in precipitation. Through a linear multiple regression analysis, it was observed that temporal variations were consistent with the meteorological parameters derived from HYSPLIT, particularly precipitation amount along the trajectory and mix depth, but are not dependent on vapour residence time in the atmosphere. These findings also indicate the importance of convective systems to control the isotopic composition of precipitation in tropical and subtropical regions.