The Indoor Environmental Quality (IEQ) combines thermal, visual, acoustic, and air-quality conditions in indoor environments and affects occupants’ health, well-being, and comfort. Performing continuous monitoring to assess IEQ is increasingly proving to be important, also due to the large amount of time that people spend in closed spaces. In the present study, the design, development, and metrological characterization of a low-cost multi-sensor device is presented. The device is part of a wider system, hereafter referred to as PROMET&O (PROactive Monitoring for indoor EnvironmenTal quality & cOmfort), that also includes a questionnaire for the collection of occupants’ feedback on comfort perception and a dashboard to show end users all monitored data. The PROMET&O multi-sensor monitors the quality conditions of indoor environments thanks to a set of low-cost sensors that measure air temperature, relative humidity, illuminance, sound pressure level, carbon monoxide, carbon dioxide, nitrogen dioxide, particulate matter, volatile organic compounds, and formaldehyde. The device architecture is described, and the design criteria related to measurement requirements are highlighted. Particular attention is paid to the calibration of the device to ensure the metrological traceability of the measurements. Calibration procedures, based on the comparison to reference standards and following commonly employed or ad hoc developed technical procedures, were defined and applied to the bare sensors of air temperature and relative humidity, carbon dioxide, illuminance, sound pressure level, particulate matter, and formaldehyde. The next calibration phase in the laboratory will be aimed at analyzing the mutual influences of the assembled multi-sensor hardware components and refining the calibration functions.

The performance of horizontal axis Wind Turbines (WTs) is strongly affected by the wind speed entering in their rotor. Generally, this quantity is not available, because the wind speed is measured on the nacelle behind the turbine rotor, providing a lower value. Therefore, two correction methods are usually employed, requiring two input quantities: the wind speed on the back of the turbine nacelle and the wind speed measured by a meteorological mast close to the turbines under analysis. However, the presence of this station in wind farms is rare and the number of WTs in the wind farm is high. This paper proposes an innovative correction, named “Statistical Method” (SM), that evaluates the efficiency of WTs by estimating the wind speed entering in the WTs rotor. This method relies on the manufacturer power curve and the data measured by the WT anemometer only, thus having the possibility to be also applied in wind farms without a meteorological station. The effectiveness of such a method is discussed by comparing the results obtained by the standard methods implemented on two turbines (rated power = 1.5 MW and 2.5 MW) of a wind power plant (nominal power = 80 MW) in Southern Italy.

The results of more than seven years (October 2010-December 2017) of continuous monitoring are presented in this paper. Eight outdoor photovoltaic (PV) plants were monitored. The monitored plants use different technologies: mono-crystalline silicon (m-Si), poli-crystalline silicon (p-Si), string ribbon silicon, copper indium gallium selenide (CIGS), thin film, and cadmium telluride (CdTe) thin film. The thin-film and m-Si modules are used both in fixed installations and on x-y tracking systems. The results are expressed in terms of the degradation rate of the efficiency of each PV plant, which is estimated using the measurements provided by a multi-channel data acquisition system that senses both electrical and environmental quantities. A comparison with the electrical characterization of each plant obtained by means of the transient charge of a capacitive load is also made. In addition, three of the monitored plants are characterized at module level, and the estimated degradation rates are compared to the values obtained with the monitoring system. The main outcome of this work can be summarized as the higher degradation rate of thin-film based PV modules with respect to silicon-based PV modules.

This paper describes a software tool that is able to remotely exercise the calibration procedure of a measurement device. Such a tool, which is based on a client-server application over the Internet, requires that the Unit Under Test (UUT) and the reference standard are programmable instruments that are connected to the PC where the client application runs. This allows the calibration of the UUT to be performed without move it, thus drastically reducing the out-of-service time. Furthermore, the presence of a skilled technician is not required at the UUT site, so that the overall calibration cost is reduced. Particular attention is payed towards the 'security' problems related to the exchange of information over the Internet and a solution is proposed in order to give an high confidence in data integrity and system inaccessibility. In the paper, the authors describe a specific application of the calibration software, which has been specialized for the remote calibration of data acquisition boards. A travelling standard, which has been specifically designed for this application, is also described

This work deals with a measuring system that is specifically designed for monitoring temperature-sensitive goods during their distribution, with the aim to conform to the cold-chain assurance requirements. The measurement problems and the constraints that are met in this application are initially highlighted, then an architecture is proposed that takes such problems into account. The proposed architecture is based on measuring nodes that are integrated into the goods, in order to identify their behavior in real operating conditions, e.g. during a typical distribution path. The measuring nodes communicates through a wireless channel with a base station, that plays the role of data concentrator and processing unit. Preliminary experimental results have been obtained that have shown the feasibility of the proposed solution and that have provided useful information for the design of the whole system.

This work estimates the uncertainty contributions of speech level parameters measured with a contact-sensor-based device and a headworn microphone. Four contributions are considered: (1) instrumental uncertainty, related to device calibration; (2) method repeatability and (3) reproducibility, estimated through repeated measurements without and with device repositioning, respectively; (4) source reproducibility, due to the variability of human speech. To ascertain changes in speech production, differences between measures should be at least higher than the expanded uncertainty. In the case of device repositioning, the expanded uncertainty combines contributions (1), (3), and (4). When the device is not repositioned, it combines contributions (2) and (4).