Role of nanostructured polymers on the improvement of electrical response-based relative humidity sensors

Nowadays, an infectious disease outbreak is considered one of the most destructive effects in the sustainable development process. The outbreak of new coronavirus (COVID-19) as an infectious disease showed that it has undesirable social, environmental, and economic impacts, and leads to serious challenges and threats. Additionally, investigating the prioritization parameters is of vital importance to reducing the negative impacts of this global crisis. Hence, the main aim of this study is to prioritize and analyze the role of certain environmental parameters. For this purpose, four cities in Italy were selected as a case study and some notable climate parameters—such as daily average temperature, relative humidity, wind speed—and an urban parameter, population density, were considered as input data set, with confirmed cases of COVID-19 being the output dataset. In this paper, two artificial intelligence techniques, including an artificial neural network (ANN) based on particle swarm optimization (PSO) algorithm and differential evolution (DE) algorithm, were used for prioritizing climate and urban parameters. The analysis is based on the feature selection process and then the obtained results from the proposed models compared to select the best one. Finally, the difference in cost function was about 0.0001 between the performances of the two models, hence, the two methods were not different in cost function, however, ANN-PSO was found to be better, because it reached to the desired precision level in lesser iterations than ANN-DE. In addition, the priority of two variables, urban parameter, and relative humidity, were the highest to predict the confirmed cases of COVID-19.

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Influence of the ambient humidity on the concentration of natural deposition-mode ice-nucleating particles

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-927-2016 ◽

2016 ◽

Vol 16 (2) ◽

pp. 927-932 ◽

Cited By ~ 3

Author(s):

M. L. López ◽

E. E. Ávila

Keyword(s):

Relative Humidity ◽

Linear Trend ◽

Ground Level ◽

Ambient Air ◽

Air Masses ◽

Ambient Relative Humidity ◽

Thermodynamic Conditions ◽

Rainy Days ◽

Deposition Mode

Abstract. This study reports measurements of deposition-mode ice-nucleating particle (INP) concentrations at ground level during the period July–December 2014 in Córdoba, Argentina. Ambient air was sampled into a cloud chamber where the INP concentration was measured at a temperature of −25 °C and a 15 % supersaturation over ice. Measurements were performed on days with different thermodynamic conditions, including rainy days. The effect of the relative humidity at ground level (RHamb) on the INP concentration was analyzed. The number of INPs activated varied from 1 L−1 at RHamb of 25 % to 30 L−1 at RHamb of 90 %. In general, a linear trend between the INP concentration and the RHamb was found, suggesting that this variability must be related to the effectiveness of the aerosols acting as INPs. From the backward trajectories analysis, it was found that the link between INP concentration and RHamb is independent of the origin of the air masses. The role of biological INPs and nucleation occurring in pores and cavities was discussed as a possible mechanism to explain the increase of the INP concentration during high ambient relative humidity events. This work provides valuable measurements of deposition-mode INP concentrations from the Southern Hemisphere where INP data are sparse so far.

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Limiting the Oxidation of WS2 Nanostructures by Oleylamine Surface Passivation for Room Temperature NH3 Sensing

10.20944/preprints202008.0150.v1 ◽

2020 ◽

Author(s):

Siziwe Gqoba ◽

Rafael Rodrigues ◽

Sharon Lerato Mphahlele ◽

Zakhele Ndala ◽

Mildred Airo ◽

...

Keyword(s):

Relative Humidity ◽

Room Temperature ◽

Surface Passivation ◽

Electrical Response ◽

Prolonged Incubation ◽

P Type ◽

2D Nanosheets ◽

Type Response ◽

And Diffusion ◽

Hierarchical Morphology

Oleylamine capped WS2 nanostructures were successfully formed at 320 °C via a relatively simple colloidal route. SEM and TEM analyses showed that the 3D nanoflowers that were initially formed disintegrated into 2D nanosheets after prolonged incubation. XPS and XRD analyses confirmed oxidation of WS2 into WO3. Sensors based on these oleylamine capped WS2 nanoflowers and nanosheets still showed a change in electrical response towards various concentrations of NH3 vapour at room temperature in a 25% relative humidity background despite the oxidation. The nanoflowers exhibited n-type response while the nanosheets displayed a p-type response towards NH3 exposure. The nanoflower based sensors showed better response to NH3 vapour exposure than the nanosheets. The sensors showed a good selectivity towards NH3 relative to acetone, ethanol, chloroform and toluene. Meanwhile, a strong interference of humidity to the NH3 response was displayed at high relative humidity levels. The results demonstrated that oleylamine limited the extent of oxidation of WS2 nanostructures. The superior sensing performance of the nanoflowers can be attributed to their hierarchical morphology which enhances the surface area and diffusion of the analyte.

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Recent changes of relative humidity: regional connection with land and ocean processes

10.5194/esd-2017-43 ◽

2017 ◽

Cited By ~ 3

Author(s):

Sergio M. Vicente-Serrano ◽

Raquel Nieto ◽

Luis Gimeno ◽

Cesar Azorin-Molina ◽

Anita Drumond ◽

...

Keyword(s):

Relative Humidity ◽

Interannual Variability ◽

Air Temperature ◽

Spatial Scales ◽

Global Scale ◽

Sea Surface ◽

Positive Trend ◽

Source Regions ◽

Strong Agreement

Abstract. We analyzed changes in surface relative humidity (RH) at the global scale from 1979 to 2014 using both observations and ERA-Interim dataset. We compared the variability and trends of RH with those of land evapotranspiration and ocean evaporation in moisture source areas across a range of selected regions worldwide. The sources of moisture for each particular region were identified by integrating different observational data and model outputs into a lagrangian approach. The aim was to account for the possible role of changes in air temperature over land, in comparison to sea surface temperature (SST), on RH variability. Results demonstrate a strong agreement between the interannual variability of RH and the interannual variability of precipitation and land evapotranspiration in regions with continentally-originated humidity. In contrast, albeit with the dominant positive trend of air temperature/SST ratio in the majority of the analyzed regions, the interannual variability of RH in the target regions did not show any significant correlation with this ratio over the source regions. Also, we did not find any significant association between the interannual variability of oceanic evaporation in the oceanic humidity source regions and RH in the target regions. Our findings stress the need for further investigation of the role of both dynamic and radiative factors in the evolution of RH over continental regions at different spatial scales.

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