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This work presents a study for assessing the technology acceptance of a contact tracing app, also proposed by us, which is a hybrid crowdsensing application (opportunistic and participatory). The goal of the app is that users are notified if they were in contact with others infected. It also allows creating a heat map identifying streets, squares, and commercial locations to which contaminated users were, allowing more assertive hygiene actions and eliminating infectious disease outbreaks. Our methodology aimed on finding whether people would be willing to share their location, as well as their health issues related to COVID-19. It is composed by a survey for verifying the interest of the proposed application; the prototype of the application; and the use of Technology Acceptance Model (TAM). We can see that the vast majority of respondents to the first survey were interested in using a contact tracking application, even though they need to share their location and report when they become infected. In addition, the proposed RISCOVID application proved to be accepted for use by participants in the second survey.

This article reports the results of experiments to synthesize a family of copolymers based on polyacrylamide (PAAM), poly(ethylene oxide) (PEO), and poly(propylene oxide) (PPO) to obtain PAAM-g-PEO and PAAM-g-PPO copolymers with varied grafted chain lengths and contents. The influence of the chemical structure, composition, and molecular architecture on the dragreduction properties was evaluated. The PAAM-g-PEO systems were prepared by solution polymerization using hydrogen peroxide as initiator, whereas the PAAM-g-PPO systems were obtained by micellar polymerization using potassium persulfate as initiator and sodium dodecyl sulfate as surfactant agent. The synthesized polymers were characterized by carbon-13 nuclear magnetic resonance (13 C-NMR) and size-exclusion chromatography. The dragreduction tests were carried out in a capillary viscosimeter in bench scale, and the performance was expressed in terms of drag-reduction percentage (%DR). The results suggest that, a determined chemical structure for each copolymer family evaluated probably promotes the ideal conformation of the chains under flow, favoring each polymer's drag-reduction action.

A large number of processes are used to treat the oily water (oil emulsions in water) produced in the petroleum industry. The treatment strategy depends not only on the strictness of the environmental requirements in the jurisdiction where the water is discharged, but also on the relative treatment cost. The present study reports tests to assess the effectiveness of removing oil from oily water by adsorption in polymer nanocomposites. These composites were prepared from ionenes (cationic polyelectrolytes) and sodium bentonite or organophilic bentonite. They were characterized by infrared spectrometry, thermogravimetry, X-ray fluorescence, and X-ray diffraction. The oil-removal effectiveness was evaluated by mixing nanocomposites and oily water in a shaker bath (batch test). In the tests conducted only with treated sodium bentonite and organophilic bentonite, the oil removal was $ 70%, whereas the use of polymer nanocomposites raised the adsorption of oil to $ 90%. These values depended on the mass of material, concentration of oil in the contaminated water, and the contact time.