An experiment was conducted to determine the effects of pressure loss, combined spacing, and. coefficients of uniformity on the dynamic fluidic sprinkler. Spline interpolation was used to convert the radial water volume into grid-type data and various pressure conditions were used to simulate the three-dimensional water distribution under square and triangular combinations of sprinklers. For each of the combinations of the sprinklers, experiments were performed at operating pressures of 0.15, 0.2, 0.25, and 0.3 MPa, respectively. To find the optimum spatial distribution of sprinklers, three different sprinkler intervals, 1R, 1.2R, and 1.4R, were performed for the square and triangular combinations. The droplet size distributions were also measured along a radial transect from the sprinkler for each operational pressure using the Thies Clima Laser Precipitation Monitor. The results demonstrated that the average values of the inclination angles of the water droplet trajectory curves were 60.78° and 68.85° as the pressure rose from 0.15 MPa to 0.3 MPa. When the pressure exceeds 0.2 MPa, the square combination\'s distribution uniformity coefficients of 25% low and high values were higher than those of the triangle combination. Triangular combination coefficients of uniformity (CU) values initially decreased and then increased as sprinkler spacing increased, with the CU value under 1.4R spacing reaching 73.85%. At a 1.2R interval, the CU value of a triangular combination was 8.49% lower than that of a square combination, which is a significant difference. Peak irrigation values for the square combination, when the pressure was changed from 0.1 to 0.3 MPa, were 29.97, 22.9, 19.8, 19.91, and 19.21 mm h-1, respectively. The CU values at 0.2, 0.25, and 0.3 MPa decreased at rates of 0.07%, 1.36%, and 0.8%, respectively, when the pressure was reduced by 10%.

Background Infections can spread within the dental clinic through many routes. Interrupting this transmission of infection within the dental office is an important part of the dental practice. This study aimed to assess the knowledge, attitude, and practice regarding precautions against droplet and airborne infections among dental students in South India. Methodology A cross-sectional, questionnaire-based survey was conducted among 236 undergraduate dental students in Chennai. The questionnaire consisted of 11 questions in three categories of knowledge, attitude, and practice regarding airborne and droplet isolation precautions. The collected data were compiled and analyzed using SPSS version 13 software (SPSS Inc., Chicago, IL, USA). Results The frequency scores of knowledge, attitude, and practice regarding droplet and airborne isolation precautions showed that dental students were very much aware of the precautions and the guidelines. The mean scores for knowledge, attitude, and practice were 7.70 ± 2.48, 37.22 ± 6.98, and 7.1 ± 1.64, respectively. There were no significant differences among subgroups (third-year students, fourth-year students, and interns) regarding knowledge, attitude, and practice. A positive linear correlation was observed between knowledge and attitude, knowledge and practice, and attitude and practice (p < 0.05). Conclusions According to the results of this study, dental students had adequate knowledge, positive attitudes, and compliance. Training programs on isolation precautions are needed to sustain and update the knowledge according to the changing trends in infectious diseases.

Nano-fluid flooding is a new method capable of improving oil recovery; however, nanoparticles (NPs) significantly affect electric dehydration, which has rarely been investigated. The effect of silica (SiO2) NPs on the droplet-interface coalescence was investigated using a high-speed digital camera under an electric field. The droplet experienced a fall, coalescence, and secondary droplet formation. The results revealed that the oil-water interfacial tension and water conductivity changed because of the SiO2 NPs. The decrease of interfacial tension facilitated droplet deformation during the falling process. However, with the increase of particle concentration, the formed particle film inhibited the droplet deformation degree. Droplet and interface are connected by a liquid bridge during coalescence, and the NP concentration also resulted in the shape of this liquid bridge changing. The increase of NP concentration inhibited the horizontal contraction of the liquid bridge while promoting vertical collapse. As a result, it did not facilitate secondary droplet formation. Moreover, the droplet falling velocity decreased, while the rising velocity of the secondary droplet increased. Additionally, the inverse calculation of the force balance equation showed that the charge of the secondary droplet also increased. This is attributed to nanoparticle accumulation, which resulted in charge accumulation on the top of the droplet.

BACKGROUND: The purpose of this study was to determine the extent of air and surface contamination of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) in four health care facilities with hospitalized coronavirus disease 2019 (COVID-19) patients.
METHODS: We investigated air and environmental contamination in the rooms of eight COVID-19 patients in four hospitals. Some patients were in negative-pressure rooms, and others were not. None had undergone aerosol-generating procedures. On days 0, 3, 5, and 7 of hospitalization, the surfaces in the rooms and anterooms were swabbed, and air samples were collected 2 m from the patient and from the anterooms.
RESULTS: All 52 air samples were negative for SARS-CoV-2 RNA. Widespread surface contamination of SARS-CoV-2 RNA was observed. In total, 89 of 320 (27%) environmental surface samples were positive for SARS-CoV-2 RNA. Surface contamination of SARS-CoV-2 RNA was common in rooms without surface disinfection and in rooms sprayed with disinfectant twice a day. However, SARS-CoV-2 RNA was not detected in a room cleaned with disinfectant wipes on a regular basis.
CONCLUSIONS: Our data suggest that remote (> 2 m) airborne transmission of SARS-CoV-2 from hospitalized COVID-19 patients is uncommon when aerosol-generating procedures have not been performed. Surface contamination was widespread, except in a room routinely cleaned with disinfectant wipes.

For P-OLED display fabrication, it is important to control the final film shape, arising from drying of volatile droplets containing polymer. Due to peripheral pinning and subsequent outward capillary flow, a coffee-ring typically develops. This is inconvenient since a spatially uniform height, above the substrate, is required to ensure uniform current across the device. Typically the droplets are deposited inside a trough-like structure on the substrate. We present a thin-film lubrication model that tracks the drying dynamics through to the final film shape. The governing equations are derived and solved numerically. We investigate the effect of the trough\'s depth and the slope of the walls. Increasing the depth or the wall\'s gradient increases coffee-ring formation. This is due to an increase in horizontal velocity, caused by the substrate\'s shape as well as delayed gelation of the polymer. The latter allows the outward capillary flow to act for a longer time, before the height becomes fixed.

BACKGROUND: In this study, an electroscrubber was designed and experimented for evaluation of integrating particle and droplet charging effects separately and jointly on collection efficiency of a spray tower and also to discover the optimal condition.
METHODS: A homogenous concentration of relatively fine particles was introduced to influent air stream and electroscrubber efficiency in purifying them was determined through the measurement of input and output particles concentration. The effect of various conditions such as particles and droplets charging alone and together (bipolar) for several applied voltages has been studied.
RESULTS: In all of experiments, the applied charging voltage has a key role in promotion of electroscrubber efficiency. Maximum collection efficiency has achieved for 15 Kilovolt (Kv). The effectiveness of bipolar charging of particles and droplets with 15 Kv was higher than that of no-charging and singly charging. In other words, efficiency can be increased from 84.43% to 93.22 for total particles and from 50.8% to 75.16% for submicron particles. The maximum improvement of collection efficiency (42.2%) relates to bipolar charging of the initial size group with diameter smaller than 0.3 micrometer (µm) and the minimum (0.5%) to sizing group of 11 with diameter 4-5 µm.
CONCLUSIONS: This approach can be an appropriate option for the purpose of purifying submicron particles in spray tower scrubbers.