Supervisory Control and Data Acquisition Approach in Node-RED: Application and Discussions

The Internet of Things (IoT) represents the binder of two worlds, specifically the real one and the digital one: tangible objects become recognizable in the virtual world, having digital matches, thus creating a network that enables the connection in-between the components. With the contemporary evolution of this domain, interconnectivity has become a primary fraction of new research and development directions. The Industrial Internet of Things (IIoT) is a concept that covers the more industrial level of the physical and digital connection and stays behind the Industry 4.0 concept. Supervisory control and data acquisition (SCADA) applications are important in the industry, their core being very present as complex products of big companies, at high prices. The Node-RED environment quickly evolved as one of the most important perspectives in IIoT, able to replace, up to a certain level, classic SCADA applications, bringing benefits to the industry. In this paper, the main focus is to evidence this aspect and to develop an application that will demonstrate the functionality of the concept, making use of protocols such as Modbus TCP (Transmission Control Protocol) for interacting with industrial devices and Message Queuing Telemetry Transport (MQTT) to interact with higher-levels, which provides a publish-subscribe structuring and a low band-width usage. The application uses logging and archiving modules based on InfluxDB database and is conceived to achieve the visual supervisory structure as close as possible to well-known SCADA solutions. The presented work results prove the efficiency of the solution.

Gas and aerosol carbon in California: comparison of measurements and model predictions in Pasadena and Bakersfield

Co-located measurements of fine particulate matter (PM2.5) organic carbon (OC), elemental carbon, radiocarbon (14C), speciated volatile organic compounds (VOCs), and OH radicals during the CalNex field campaign provide a unique opportunity to evaluate the Community Multiscale Air Quality (CMAQ) model's representation of organic species from VOCs to particles. Episode average daily 23 h average 14C analysis indicates PM2.5 carbon at Pasadena and Bakersfield during the CalNex field campaign was evenly split between contemporary and fossil origins. CMAQ predicts a higher contemporary carbon fraction than indicated by the 14C analysis at both locations. The model underestimates measured PM2.5 organic carbon at both sites with very little (7% in Pasadena) of the modeled mass represented by secondary production, which contrasts with the ambient-based SOC / OC fraction of 63% at Pasadena. Measurements and predictions of gas-phase anthropogenic species, such as toluene and xylenes, are generally within a factor of 2, but the corresponding SOC tracer (2,3-dihydroxy-4-oxo-pentanoic acid) is systematically underpredicted by more than a factor of 2. Monoterpene VOCs and SOCs are underestimated at both sites. Isoprene is underestimated at Pasadena and overpredicted at Bakersfield and isoprene SOC mass is underestimated at both sites. Systematic model underestimates in SOC mass coupled with reasonable skill (typically within a factor of 2) in predicting hydroxyl radical and VOC gas-phase precursors suggest error(s) in the parameterization of semivolatile gases to form SOC. Yield values (α) applied to semivolatile partitioning species were increased by a factor of 4 in CMAQ for a sensitivity simulation, taking into account recent findings of underestimated yields in chamber experiments due to gas wall losses. This sensitivity resulted in improved model performance for PM2.5 organic carbon at both field study locations and at routine monitor network sites in California. Modeled percent secondary contribution (22% at Pasadena) becomes closer to ambient-based estimates but still contains a higher primary fraction than observed.

Optimizing treatment for reduction of disinfection by-product (DBP) formation

Recent studies in communities in greater Cairo, Egypt have identified trihalomethanes (THMs) and haloacetic acids (HAAs) at levels that exceed regulatory limits depending upon the season. The objective of this study was to better understand the formation of DBPs in Nile River source water with a view toward optimizing conventional treatment, focusing on enhanced coagulation, to achieve reduction in DBP formation potential (FP) in a cost-effective scheme. To this end, characterisation of natural organic matter (NOM) in Nile raw water and after treatment by fractionating according to hydrophobic-hydrophilic properties was included in the analysis. Seasonal variations in raw water quality were found to be important for achieving optimum reduction of turbidity and DBP formation. In summer, alkalinity is lower; therefore, enhanced coagulation with 30 mg/L alum can be done at pH 6 without excessive additions of acid, and satisfactory reductions in turbidity and DBPs attained. During the remainder of the year, high alkalinity results in enhanced coagulation at about pH 6.5 and notably lower reduction of NOM, THMFP, and HAAs versus summer conditions. Supplementing enhanced coagulation with 10 mg/L PAC is highly recommended for these conditions as it improves removal of all DBP indicators. The transphilic fraction was the main contributor to DBP formation and the primary fraction removed by enhanced coagulation for achieving gains in THMFP reduction.