Cross-Talk Effects in the Uncertainty Estimation of Multiplexed Data Acquisition Systems

This paper deals with the analysis of multi-channel data-acquisition systems with the aim of identifying and combining the main uncertainty contributions according to the GUM framework. Particular attention has been paid towards cross-talk effect, which could be an important uncertainty contribution in multiplexed data-acquisition systems. The uncertainty analysis is described for three commercial data acquisition devices highlighting that cross-talk specifications are often not suitable for a reliable uncertainty estimation in operating conditions. For this reason, an experimental set-up has been arranged to fully characterize the inter-channel effects of the investigated devices. The obtained results have highlighted that a proper characterization of a data-acquisition system is effective in estimating the actual performance at the frequency of interest and in the operating conditions for the source resistance and the input-channel configuration. Eventually, a customized procedure has been proposed that is effective in correcting the cross-talk effects also in very severe conditions of inter-channel disturbance

A Fiber Optical Sensor For Non–Contact Vibration Measurements

This paper describes an intensity based optical sensor for the evaluation of accelerations from non-contact displacement measurements. Plastic optical fibers are used to collect the reflected light from several points on the vibrating surface, allowing the reconstruction of the vibration distribution. Two compensation techniques to reduce systematic effects due to the target reflectivity are also described and compared: one is based on the spectral analysis of the received optical signal and the other takes advantage of a reference displacement sensor. Experimental results in real conditions during vibration tests have demonstrated the capability to measure sub-micrometer vibration amplitudes up to about 40 kHz

Fibre probe for tumour laser thermotherapy with integrated temperature measuring capabilities

The development and preliminary characterisation of a novel fibre probe for laser thermotherapy of solid tumours are presented. The probe introduces two innovative features: the tailoring of the laser irradiation pattern to adapt it also for larger tumour applications, and the all-optical real time evaluation of the induced temperature increase. These features are simultaneously obtained by integrating in a single capillary tube a laser delivery fibre with properly micro-structured tip surface together with some fibre Bragg gratings. Preliminary validation examples in human liver phantoms have demonstrated the viability of the proposed approach for the development of a whole set of new probes for laser ablation in medical applications

Long-term monitoring of photovoltaic plants

Peer Reviewe

In-field monitoring of eight photovoltaic plants: Degradation rate over seven years of continuous operation

The results of more than seven years (October 2010-December 2017) of continuous monitoring are presented in this paper that refer to eight outdoors PhotoVoltaic (PV) plants. The monitored plants are based on 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. Thin-film and m-Si modules are used both in fixed installation and on x-y tracking systems. The results are expressed in terms of degradation rate of the efficiency of each PV plant, which is estimated from 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 proposed. In addition, three of the monitored plants have been characterized at module level and the estimated degradation rates have been compared to the values obtained with the monitoring system. The main outcome of this work can be summarized in a higher degradation rate of thin-film based PV modules with respect to silicon-based PV modules

Monitoring of the primary drying of a lyophilization process in vials

An innovative and modular system (LyoMonitor) for monitoring the primary drying of a lyophilization process in vials is illustrated: it integrates some commercial devices (pressure gauges, moisture sensor and mass spectrometer), an innovative balance and a manometric temperature measurement system based on an improved algorithm (DPE) to estimate sublimating interface temperature and position, product temperature profile, heat and mass transfer coefficients. A soft-sensor using a multipoint wireless thermometer can also estimate the previous parameters in a large number of vials. The performances of the previous devices for the determination of the end of the primary drying are compared. Finally, all these sensors can be used for control purposes and for the optimization of the process recipe; the use of DPE in a control loop will be shown as an exampl

Long-Term Monitoring of Photovoltaic Plants

This paper deals with a data-acquisition system that has been specifically developed for a long-term monitoring of ten different photovoltaic plants. The main goals of the system consist in estimating the drift of the plant components, mainly photovoltaic modules and power inverters, and comparing the performance of the ten plants, which are based on different technologies and architectures. Owing to these goals, the traceabilityassurance of the obtained measurements is mandatory, hence the data-acquisition system has been designed to be easily calibrated and, if necessary, adjusted to compensate for measuring-chain drifts. In addition, the measurement uncertainty, which has to be suitable to distinguish the behaviour of the different PV plants, has to be stated for each of the estimated parameters. A brief description of the data-acquisition system is provided and its measurement capabilities are highlighted in terms of measured quantities and expected uncertainty. Results that refer to a period of thirty months are also reported

Comparison of correction methods of wind speed for performance evaluation of wind turbines

The performance of horizontal axis wind turbines strongly depends on the speed of the wind that enters in the rotor of the turbine. Unfortunately, this quantity is rarely available since the wind speed is measured on the back of the turbine, where a lower value is present. For this reason, two correction methods are usually employed that require two input quantities: the wind speed on the back of the turbine nacelle and the wind speed detected by a meteorological station close to the investigated turbine. Since an anemometric station is not always available, a third method is here proposed that does not require this input quantity. The proposed method relies on the wind speed on the back of the turbine and the manufacturer power curve. The effectiveness of such a method is shown by comparison to the results obtained with the standard methods implemented on a wind power plant in Southern Italy

Linearly chirped fiber Bragg grating response to thermal gradient: from bench tests to the real-time assessment during in vivo laser ablations of biological tissue

The response of a fiber optic sensor [linearly chirped fiber Bragg grating (LCFBG)] to a linear thermal gradient applied on its sensing length (i.e., 1.5 cm) has been investigated. After these bench tests, we assessed their feasibility for temperature monitoring during thermal tumor treatment. In particular, we performed experi- ments during ex vivo laser ablation (LA) in pig liver and in vivo thermal ablation in animal models (pigs). We investigated the following: (i) the relationship between the full width at half maximum of the LCFBG spectrum and the temperature difference among the extremities of the LCFBG and (ii) the relationship between the mean spectrum wavelength and the mean temperature acting on the LCFBG sensing area. These relationships showed a linear trend during both bench tests and LA in animal models. Thermal sensitivity was significant although different values were found with regards to bench tests and animal experiments. The linear trend and significant sensitivity allow hypothesizing a future use of this kind of sensor to monitor both temperature gradient and mean temperature within a tissue undergoing thermal treatment

Species Review of Amphibian Extinction Risks in Madagascar: Conclusions from the Global Amphibian Assessment

We assessed the extinction risks of Malagasy amphibians by evaluating their distribution, occurrence in protected areas, population trends, habitat quality, and prevalence in commercial trade. We estimated and mapped the distribution of each of the 220 described Malagasy species and applied, for the first time, the IUCN Red List categories and criteria to all species described at the time of the assessment. Nine species were categorized as critically endangered, 21 as endangered, and 25 as vulnerable. The most threatened species occur on the High Plateau and/or have been subjected to overcollection for the pet trade, but restricted extent of occurrence and ongoing habitat destruction were identified as the most important factors influencing extinction threats. The two areas with the majority of threatened species were the northern Tsaratanana-Marojejy-Masoala highlands and the southeastern Anosy Mountains. The current system of protected areas includes 82% of the threatened amphibian species. Of the critically endangered species, 6 did not occur in any protected area. For conservation of these species we recommend the creation of a reserve for the species of the Mantella aurantiaca group, the inclusion of two Scaphiophryne species in the Convention on the International Trade in Endangered Species Appendix II, and the suspension of commercial collecting for Mantella cowani . Field surveys during the last 15 years reveal no pervasive extinction of Malagasy amphibians resulting from disease or other agents, as has been reported in some other areas of the world.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75394/1/j.1523-1739.2005.00249.x.pd