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Scientific Reports Apr 2022It is significant to evaluate the air quality scientifically for the management of air pollution. As an air quality comprehensive evaluation problem, its uncertainty can...
It is significant to evaluate the air quality scientifically for the management of air pollution. As an air quality comprehensive evaluation problem, its uncertainty can be effectively addressed by the Dempster-Shafer (D-S) evidence theory. However, there is not enough research on air quality comprehensive assessment using D-S theory. Aiming at the counterintuitive fusion results of the D-S combination rule in the field of comprehensive decision, an improved evidence theory with evidence weight and evidence decision credibility (here namely DCre-Weight method) is proposed, and it is used to comprehensively evaluate air quality. First, this method determines the weights of evidence by the entropy weight method and introduces the decision credibility by calculating the dispersion of different evidence decisions. An algorithm case shows that the credibility of fusion results is improved and the uncertainty is well expressed. It can make reasonable fusion results and solve the problems of D-S. Then, the air quality evaluation model based on improved evidence theory (here namely the DCreWeight model) is proposed. Finally, according to the hourly air pollution data in Xi'an from June 1, 2014, to May 1, 2016, comparisons are made with the D-S, other improved methods of evidence theory, and a recent fuzzy synthetic evaluation method to validate the effectiveness of the model. Under the national AQCI standard, the MAE and RMSE of the DCreWeight model are 1.02 and 1.17. Under the national AQI standard, the DCreWeight model has the minimal MAE, RMSE, and maximal index of agreement, which validated the superiority of the DCreWeight model. Therefore, the DCreWeight model can comprehensively evaluate air quality. It can provide a scientific basis for relevant departments to prevent and control air pollution.
Topics: Air; Air Pollutants; Air Pollution; Entropy; Uncertainty
PubMed: 35388022
DOI: 10.1038/s41598-022-09344-0 -
Biomedizinische Technik. Biomedical... Feb 2023The effect of the presence of an air bubble, inside an infusion line, on the time (Tnew) needed for a new medication to reach the patient after a syringe exchange was...
The effect of the presence of an air bubble, inside an infusion line, on the time (Tnew) needed for a new medication to reach the patient after a syringe exchange was studied in this paper. If an air bubble escapes through an air filter, then a sudden drop in pressure occurs, causing a relaxation of the compressible part of the syringe, followed by a gradual restoration of the flow rate in the line. We modeled this phenomenon mathematically and measured it experimentally . In an example with a pump flow rate of 5 mL/h and an air bubble of 1 cm length inside an infusion line (diameter 1 mm) with an air filter, both theory and experiment yield an additional increase of at least 600% in delay time if a naive estimate (based on the size of the bubble alone) is replaced by a more realistic estimate incorporating compressibility. Furthermore, we show that an air bubble in a line without air filter may increase Tnew by a factor 2, depending on the initial position of the air bubble. We conclude that an air bubble in an infusion line causes delays that may not be expected by health care professionals.
Topics: Humans; Air Filters; Medication Errors; Infusion Pumps; Equipment Failure; Air
PubMed: 36524405
DOI: 10.1515/bmt-2022-0056 -
Environmental Monitoring and Assessment Mar 2022Most governmental initiatives in India, to leash down urban air pollution, have yielded little results till date, largely due to purely technocratic vision, which is... (Meta-Analysis)
Meta-Analysis Review
Most governmental initiatives in India, to leash down urban air pollution, have yielded little results till date, largely due to purely technocratic vision, which is shrouded by technological, economic, social, institutional, and political hardships. We present this reflective article on urban greenery, as a proposition to urban authorities (e.g., pollution regulators, environmental systems' managers, urban landscape planners, environmental policy makers), shift from purely technocratic way of thinking to thinking with nature, by strategic greening of urban spaces, for long-term air pollution prevention and control measures. To that end, we offer a meta-analysis of recent (post 2005) global literature using four-stage PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) approach. We open the narrative by briefing about main pollutant filtration mechanisms by trees, followed by cognitive aspects of species selection (e.g., deciduous vs. evergreen, air pollution tolerance index, environmental stressors). Till date, most Indian studies on urban greenery mostly but focused on physiological aspects of trees. Here, we draw attention of urban authorities to an equally compelling, but yet less explored, aspect: design criteria, with reference to two most common urban configurations, namely, street canyon and open road. With pictorial depictions, we enumerate various categories of street canyons and discuss aspect ratio (building height to street width) and various wind flow regimes (isolated roughness, wake interface, and skimming), that the urban authorities should be cognizant about to maximize pollutant removal efficiency. For open road, we discuss vegetation barriers, with special emphasis on canopy porosity/density functions. In the final sections, we reflect on a potential systems' thinking approach for on-ground implementation, comprising of revamping of urban forestry programs, research and development, community mobilization and stakeholder engagement, and strategic outreach. In addition, we emphasize on means to harness co-benefits of urban greenery, beyond mere pollutant removal, to garner support from urban residents' communities. Last but not the least, we also caution the urban authorities about the undesirable outcomes of urban greenery that will require more process-level research.
Topics: Air Pollutants; Air Pollution; Cities; Environmental Monitoring; Models, Theoretical; Vehicle Emissions; Wind
PubMed: 35233683
DOI: 10.1007/s10661-022-09808-w -
PloS One 2015Conventional wisdom among cave divers is that submerged caves in aquifers, such as in Florida or the Yucatan, are unstable due to their ever-growing size from limestone...
Conventional wisdom among cave divers is that submerged caves in aquifers, such as in Florida or the Yucatan, are unstable due to their ever-growing size from limestone dissolution in water. Cave divers occasionally noted partial cave collapses occurring while they were in the cave, attributing this to their unintentional (and frowned upon) physical contact with the cave walls or the aforementioned "natural" instability of the cave. Here, we suggest that these cave collapses do not necessarily result from cave instability or contacts with walls, but rather from divers bubbles rising to the ceiling and reducing the buoyancy acting on isolated ceiling rocks. Using familiar theories for the strength of flat and arched (un-cracked) beams, we first show that the flat ceiling of a submerged limestone cave can have a horizontal expanse of 63 meters. This is much broader than that of most submerged Florida caves (~ 10 m). Similarly, we show that an arched cave roof can have a still larger expanse of 240 meters, again implying that Florida caves are structurally stable. Using familiar bubble dynamics, fluid dynamics of bubble-induced flows, and accustomed diving practices, we show that a group of 1-3 divers submerged below a loosely connected ceiling rock will quickly trigger it to fall causing a "collapse". We then present a set of qualitative laboratory experiments illustrating such a collapse in a circular laboratory cave (i.e., a cave with a circular cross section), with concave and convex ceilings. In these experiments, a metal ball represented the rock (attached to the cave ceiling with a magnet), and the bubbles were produced using a syringe located at the cave floor.
Topics: Air; Calcium Carbonate; Caves; Groundwater; Mechanical Phenomena
PubMed: 25849088
DOI: 10.1371/journal.pone.0122349 -
Journal of Oleo Science 2015According to the conventional Gibbs adsorption model, which is a common assumption about the molecular concentration at surfaces, the adsorbed film of soluble... (Review)
Review
According to the conventional Gibbs adsorption model, which is a common assumption about the molecular concentration at surfaces, the adsorbed film of soluble amphiphiles is located at the air/solution interface just like Langmuir monolayer which is illustrated in many physical chemistry text books on "Colloid and Interface Science". According to many proofs of the experimental results here, the newer idea for the surface adsorption is confirmed and explained, which is quite different from the conventional Gibbs surface excess model at the air/solution interface.
Topics: Adsorption; Air; Ethylene Glycol; Models, Theoretical; Pyrenes; Solubility; Solutions; Spectrometry, Fluorescence; Surface Properties; Surface-Active Agents; Thermogravimetry; Unilamellar Liposomes; Volatilization; Water
PubMed: 25742921
DOI: 10.5650/jos.ess14213 -
International Journal of Biometeorology Sep 2021The paper analyses the temporal and spatial variability of the Universal Thermal Climate Index (UTCI) in Poland in summer. Summer is the season with the highest...
The paper analyses the temporal and spatial variability of the Universal Thermal Climate Index (UTCI) in Poland in summer. Summer is the season with the highest intensity of tourism traffic that is why it is important to determine biometeorological conditions, especially in popular tourist destinations such as coastal, mountain and urban areas, in the times of climate changes. The analysis was based on data from 18 stations of IMGW-PIB (Institute of Meteorology and Water Management-National Research Institute), distributed evenly in the territory of the country, and representing all eight bioclimatic regions. The data include air temperature, relative humidity, wind velocity and cloudiness at 12 UTC from summer months: June, July and August from the years 2001-2018. Thermoneutral zone was the most frequently occurring UTCI class in Poland. It was recorded during 56-75% of summer days (with the exception of mountain stations, where it occurred on 30-35% of days). Moderate heat stress is the second most frequently occurring category with a frequency from 18 to 29% with the exception of mountain and coastal areas. Extreme and very strong cold stress occurred particularly in high mountain stations, and was sporadically observed at the coast of the Baltic Sea; however, the occurrence of such conditions decreases, which if favourable for beach tourism. No cases of extreme heat stress were recorded in any of the stations. The most unfavourable bioclimatic conditions were characteristic of the Upland Region (IV), represented by Kraków and Sandomierz, where very strong heat stress occurred with a 10% frequency. This is a limitation for urban tourism in those regions. The highest UTCI values were recorded in Kraków on 17 July 2007 and 29 July 2005. The highest number of cases with strong and very strong heat stress was recorded in 2015 as a consequence of the heat wave observed in Poland in the first half of August. In the majority of the analysed stations, in the second half of the analysed period (2010-2018), an increase in the number of days with strong and very strong heat stress was observed in comparison with the first half of period (2001-2009). The highest frequency of such days was observed in July. Based on the data, there are 4 potential periods of occurrence of such days, with two most intense being 26. July-13 August and 14-22 July.
Topics: Heat Stress Disorders; Humans; Meteorology; Poland; Seasons; Wind
PubMed: 32681383
DOI: 10.1007/s00484-020-01965-2 -
Journal of Infection and Public Health 2019Control of airborne microbial contamination is important in operating rooms (ORs). To keep airborne contamination low, guidelines should highlight the importance of air...
BACKGROUND
Control of airborne microbial contamination is important in operating rooms (ORs). To keep airborne contamination low, guidelines should highlight the importance of air turnover. The aims of the study were: (1) to verify the association between air turnover and airborne contamination in ORs; and (2) to identify a statistical relationship between air turnover and airborne microbial contamination.
METHODS
A cross sectional study was carried out from November 2014 to July 2017 in the teaching Hospital of Siena. Nineteen ORs (14 with turbulent and 5 with laminar flow ventilation) were surveyed a total of 59 times under operating conditions. Air samples were collected with an air sampler. Petri dishes, incubated at 36 °C for 48 h, were used to quantify colony forming units in the samples (CFU). The data was transformed to evaluate several statistically significant nonlinear associations between air turnover, quantified as air changes per hour (ACH) and CFU per cubic meter of air (p < 0.05).
RESULTS
A log-linear regression model provided the best fit between ACH and CFU for laminar (p = 0.013; R = 0.3911) and turbulent flow systems (p = 0.002; R = 0.3443). The corresponding model was: ln(CFU) = (a - b*ACH), where the regression parameters were estimated at a = 4.02 and b = 0.037 for laminar flow and a = 5.24 and b = 0.067 for turbulent flow.
CONCLUSIONS
Italian guidelines indicate microbial load limits of 20 and 180 CFU/m for operating rooms with laminar and turbulent flow ventilation, respectively. The model allowed us to evaluate the minimum number of ACHs to keep CFU within these limits. Ad hoc measurements in other environments can be used to calibrate the relationship between ACH and CFU.
Topics: Air Microbiology; Air Movements; Colony Count, Microbial; Cross-Sectional Studies; Hospitals, Teaching; Italy; Operating Rooms; Ventilation
PubMed: 31155407
DOI: 10.1016/j.jiph.2019.05.010 -
Biomedical Engineering Online Jun 2018Air ions are molecules of air that have become ionized-that is, they have either lost or gained an electrical charge. Past speculation has suggested that exposure to... (Review)
Review
BACKGROUND
Air ions are molecules of air that have become ionized-that is, they have either lost or gained an electrical charge. Past speculation has suggested that exposure to positive air ions may be harmful to one's health, while exposure to negative air ions may be associated with beneficial health effects. Air ions arise from natural sources as well as direct-current transmission lines and commercial ionizers. Several recent clinical studies have suggested therapeutic effects of air ions on various types of depression at exposure levels 10- to 1000-fold higher than most previous human studies. The aim of this study was to assess the evidence from studies of laboratory animals for beneficial or adverse effects of air ions on health.
METHODS
Sixty-two studies (1935-2015) in nine topics areas were evaluated for quality and potential systematic bias by ARRIVE guidelines. Standardized mean differences or proportional differences between exposed and control groups were computed for 44 studies to quantitatively assess the strength of the evidence for exposure-related effects.
RESULTS
Many of the studies were conducted before 1990 and exhibited various reporting and methodological deficiencies, including small sample size, failure to control for the influence of potential confounding variables, lack of randomized assignment to treatment groups and blinded analyses, and statistical errors relating to treating group-exposed animals as individuals. The highest quality studies consistently reported no effects of exposure on any of the endpoints examined. There were no evident dose-response relationships within or across studies.
CONCLUSIONS
Experimental studies of laboratory animals exposed to positive and negative air ions for minutes to years over a five-log unit range of intensities did not suggest any consistent or reliable effects on measures of behavior, learning and memory, neurotransmitters, tracheal function, respiratory infection, cardiovascular function, reproduction and growth, carcinogenesis, or other health endpoints. These data do not provide evidence of adverse or beneficial effects of air ion exposure on health, and did not suggest any biological mechanism of interaction, except perhaps for mechanosensory stimulation of body surfaces by static electric fields at high air ion concentrations.
Topics: Air; Animals; Animals, Laboratory; Behavior, Animal; Physiological Phenomena
PubMed: 29866122
DOI: 10.1186/s12938-018-0499-z -
Sensors (Basel, Switzerland) Sep 2022The air-door is an important device for adjusting the air flow in a mine. It opens and closes within a short time owing to transportation and other factors. Although the...
The air-door is an important device for adjusting the air flow in a mine. It opens and closes within a short time owing to transportation and other factors. Although the switching sensor alone can identify the air-door opening and closing, it cannot relate it to abnormal fluctuations in the wind speed. Large fluctuations in the wind-velocity sensor data during this time can lead to false alarms. To overcome this problem, we propose a method for identifying air-door opening and closing using a single wind-velocity sensor. A multi-scale sliding window (MSSW) is employed to divide the samples. Then, the data global features and fluctuation features are extracted using statistics and the discrete wavelet transform (DWT). In addition, a machine learning model is adopted to classify each sample. Further, the identification results are selected by merging the classification results using the non-maximum suppression method. Finally, considering the safety accidents caused by the air-door opening and closing in an actual production mine, a large number of experiments were carried out to verify the effect of the algorithm using a simulated tunnel model. The results show that the proposed algorithm exhibits superior performance when the gradient boosting decision tree (GBDT) is selected for classification. In the data set composed of air-door opening and closing experimental data, the accuracy, precision, and recall rates of the air-door opening and closing identification are 91.89%, 93.07%, and 91.07%, respectively. In the data set composed of air-door opening and closing and other mine production activity experimental data, the accuracy, precision, and recall rates of the air-door opening and closing identification are 89.61%, 90.31%, and 88.39%, respectively.
Topics: Algorithms; Machine Learning; Wavelet Analysis; Wind
PubMed: 36146187
DOI: 10.3390/s22186837 -
Langmuir : the ACS Journal of Surfaces... Jan 2022The behavior of Langmuir monolayers of saturated and unsaturated C18 triglycerides (TAGs) was studied as two-dimensional (2D) models for paint systems at the air-water...
The behavior of Langmuir monolayers of saturated and unsaturated C18 triglycerides (TAGs) was studied as two-dimensional (2D) models for paint systems at the air-water interface or transferred onto solid films. The organization of saturated tristearin (C18:0) monolayer was probed thanks to grazing incidence X-ray diffraction: one observes a hexagonal packing of the chains perpendicular to the air-water interface, in contrast to what is described in the literature. Conversely, the mono- and polyunsaturated TAGs (triolein C18:1, trilinolein C18:2, and trilinolenin C18:3) monolayers do not present any organization at the air-water interface but do exhibit peculiar reactivity regarding the air atmosphere. The obtained results derived from the evolution of surface pressure-molecular area isotherms and monolayer compressibility under different atmospheres over time, combined with ultrahigh-vacuum infrared (UHV-FTIR) spectroscopy, showed the adsorption of O molecules in the monolayer together with chemical reactions with hydrocarbon chains. The kinetic effect of lead ions, known to be efficient siccative agents in oil paints, was also assessed: the addition of Pb in the subphase induces an increase of the O adsorption.
Topics: Adsorption; Air; Ions; Surface Properties; Triolein; Water
PubMed: 34985293
DOI: 10.1021/acs.langmuir.1c02613