No abstract

Quinoa starch nanocrystals (QSNCs), obtained by acid hydrolysis, were used as a reinforcing filler in cassava starch films. The influence of QSNC concentrations (0, 2.5, 5.0, 7.5 and 10%, w/w) on the film’s physical and surface properties was investigated. QSNCs exhibited conical and parallelepiped shapes. An increase of the QSNC concentration, from 0 to 5%, improved the film’s tensile strength from 6.5 to 16.5 MPa, but at 7.5%, it decreased to 11.85 MPa. Adequate exfoliation of QSNCs in the starch matrix also decreased the water vapor permeability (~17%) up to a 5% concentration. At 5.0% and 7.5% concentrations, the films increased in roughness, water contact angle, and opacity, whereas the brightness decreased. Furthermore, at these concentrations, the film’s hydrophilic nature changed (water contact angle values of >65°). The SNC addition increased the film opacity without causing major changes in color. Other film properties, such as thickness, moisture content and solubility, were not affected by the QSNC concentration. The DSC (differential scanning calorimetry) results indicated that greater QSNC concentrations increased the second glass transition temperature (related to the biopolymer-rich phase) and the melting enthalpy. However, the film’s thermal stability was not altered by the QSNC addition. These findings contribute to overcoming the starch-based films’ limitations through the development of nanocomposite materials for future food packaging applications.

In this paper, we describe a modular data acquisition system developed as the foundation of a cosmic ray detector network. Each detector setup (henceforth referred as a station) is composed of an independent hardware device that can be controlled and read-out through the Internet. This device is designed to acquire and process the signal of up to eight different detector planes. Each of these detector planes uses plastic scintillator slabs that are optically coupled to silicon photomultipliers (SiPM). Within a single station, different geometries and plane orientations are possible using the same baseline design. The main readout is based on a programmable system-on-a-chip (PSoC), a flexible and re-configurable commodity hardware that is used to implement the trigger and timing logic. A Time to Digital Converter (TDC) is used to determine the precise timing of the event relative to a GPS timing signal and to estimate the signal amplitude through the Time-over-Threshold (ToT) method. An auxiliary set of sensors provide environmental information and station detector planes orientation that, together with other operation data, are periodically sent to a server using the MQTT protocol. Data is cached using an in-memory database for online monitoring and further persisted into a SQL database for offline analysis. The server framework is based in software application containers allowing easy replication of the server infrastructure.